Source file src/cmd/compile/internal/ssagen/ssa.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ssagen
     6  
     7  import (
     8  	"bufio"
     9  	"bytes"
    10  	"fmt"
    11  	"go/constant"
    12  	"html"
    13  	"internal/buildcfg"
    14  	"os"
    15  	"path/filepath"
    16  	"sort"
    17  	"strings"
    18  
    19  	"cmd/compile/internal/abi"
    20  	"cmd/compile/internal/base"
    21  	"cmd/compile/internal/ir"
    22  	"cmd/compile/internal/liveness"
    23  	"cmd/compile/internal/objw"
    24  	"cmd/compile/internal/reflectdata"
    25  	"cmd/compile/internal/ssa"
    26  	"cmd/compile/internal/staticdata"
    27  	"cmd/compile/internal/typecheck"
    28  	"cmd/compile/internal/types"
    29  	"cmd/internal/obj"
    30  	"cmd/internal/objabi"
    31  	"cmd/internal/src"
    32  	"cmd/internal/sys"
    33  
    34  	rtabi "internal/abi"
    35  )
    36  
    37  var ssaConfig *ssa.Config
    38  var ssaCaches []ssa.Cache
    39  
    40  var ssaDump string     // early copy of $GOSSAFUNC; the func name to dump output for
    41  var ssaDir string      // optional destination for ssa dump file
    42  var ssaDumpStdout bool // whether to dump to stdout
    43  var ssaDumpCFG string  // generate CFGs for these phases
    44  const ssaDumpFile = "ssa.html"
    45  
    46  // ssaDumpInlined holds all inlined functions when ssaDump contains a function name.
    47  var ssaDumpInlined []*ir.Func
    48  
    49  func DumpInline(fn *ir.Func) {
    50  	if ssaDump != "" && ssaDump == ir.FuncName(fn) {
    51  		ssaDumpInlined = append(ssaDumpInlined, fn)
    52  	}
    53  }
    54  
    55  func InitEnv() {
    56  	ssaDump = os.Getenv("GOSSAFUNC")
    57  	ssaDir = os.Getenv("GOSSADIR")
    58  	if ssaDump != "" {
    59  		if strings.HasSuffix(ssaDump, "+") {
    60  			ssaDump = ssaDump[:len(ssaDump)-1]
    61  			ssaDumpStdout = true
    62  		}
    63  		spl := strings.Split(ssaDump, ":")
    64  		if len(spl) > 1 {
    65  			ssaDump = spl[0]
    66  			ssaDumpCFG = spl[1]
    67  		}
    68  	}
    69  }
    70  
    71  func InitConfig() {
    72  	types_ := ssa.NewTypes()
    73  
    74  	if Arch.SoftFloat {
    75  		softfloatInit()
    76  	}
    77  
    78  	// Generate a few pointer types that are uncommon in the frontend but common in the backend.
    79  	// Caching is disabled in the backend, so generating these here avoids allocations.
    80  	_ = types.NewPtr(types.Types[types.TINTER])                             // *interface{}
    81  	_ = types.NewPtr(types.NewPtr(types.Types[types.TSTRING]))              // **string
    82  	_ = types.NewPtr(types.NewSlice(types.Types[types.TINTER]))             // *[]interface{}
    83  	_ = types.NewPtr(types.NewPtr(types.ByteType))                          // **byte
    84  	_ = types.NewPtr(types.NewSlice(types.ByteType))                        // *[]byte
    85  	_ = types.NewPtr(types.NewSlice(types.Types[types.TSTRING]))            // *[]string
    86  	_ = types.NewPtr(types.NewPtr(types.NewPtr(types.Types[types.TUINT8]))) // ***uint8
    87  	_ = types.NewPtr(types.Types[types.TINT16])                             // *int16
    88  	_ = types.NewPtr(types.Types[types.TINT64])                             // *int64
    89  	_ = types.NewPtr(types.ErrorType)                                       // *error
    90  	_ = types.NewPtr(reflectdata.MapType())                                 // *runtime.hmap
    91  	_ = types.NewPtr(deferstruct())                                         // *runtime._defer
    92  	types.NewPtrCacheEnabled = false
    93  	ssaConfig = ssa.NewConfig(base.Ctxt.Arch.Name, *types_, base.Ctxt, base.Flag.N == 0, Arch.SoftFloat)
    94  	ssaConfig.Race = base.Flag.Race
    95  	ssaCaches = make([]ssa.Cache, base.Flag.LowerC)
    96  
    97  	// Set up some runtime functions we'll need to call.
    98  	ir.Syms.AssertE2I = typecheck.LookupRuntimeFunc("assertE2I")
    99  	ir.Syms.AssertE2I2 = typecheck.LookupRuntimeFunc("assertE2I2")
   100  	ir.Syms.AssertI2I = typecheck.LookupRuntimeFunc("assertI2I")
   101  	ir.Syms.AssertI2I2 = typecheck.LookupRuntimeFunc("assertI2I2")
   102  	ir.Syms.CgoCheckMemmove = typecheck.LookupRuntimeFunc("cgoCheckMemmove")
   103  	ir.Syms.CgoCheckPtrWrite = typecheck.LookupRuntimeFunc("cgoCheckPtrWrite")
   104  	ir.Syms.CheckPtrAlignment = typecheck.LookupRuntimeFunc("checkptrAlignment")
   105  	ir.Syms.Deferproc = typecheck.LookupRuntimeFunc("deferproc")
   106  	ir.Syms.Deferprocat = typecheck.LookupRuntimeFunc("deferprocat")
   107  	ir.Syms.DeferprocStack = typecheck.LookupRuntimeFunc("deferprocStack")
   108  	ir.Syms.Deferreturn = typecheck.LookupRuntimeFunc("deferreturn")
   109  	ir.Syms.Duffcopy = typecheck.LookupRuntimeFunc("duffcopy")
   110  	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
   111  	ir.Syms.GCWriteBarrier[0] = typecheck.LookupRuntimeFunc("gcWriteBarrier1")
   112  	ir.Syms.GCWriteBarrier[1] = typecheck.LookupRuntimeFunc("gcWriteBarrier2")
   113  	ir.Syms.GCWriteBarrier[2] = typecheck.LookupRuntimeFunc("gcWriteBarrier3")
   114  	ir.Syms.GCWriteBarrier[3] = typecheck.LookupRuntimeFunc("gcWriteBarrier4")
   115  	ir.Syms.GCWriteBarrier[4] = typecheck.LookupRuntimeFunc("gcWriteBarrier5")
   116  	ir.Syms.GCWriteBarrier[5] = typecheck.LookupRuntimeFunc("gcWriteBarrier6")
   117  	ir.Syms.GCWriteBarrier[6] = typecheck.LookupRuntimeFunc("gcWriteBarrier7")
   118  	ir.Syms.GCWriteBarrier[7] = typecheck.LookupRuntimeFunc("gcWriteBarrier8")
   119  	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
   120  	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
   121  	ir.Syms.InterfaceSwitch = typecheck.LookupRuntimeFunc("interfaceSwitch")
   122  	ir.Syms.Memmove = typecheck.LookupRuntimeFunc("memmove")
   123  	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
   124  	ir.Syms.Msanwrite = typecheck.LookupRuntimeFunc("msanwrite")
   125  	ir.Syms.Msanmove = typecheck.LookupRuntimeFunc("msanmove")
   126  	ir.Syms.Asanread = typecheck.LookupRuntimeFunc("asanread")
   127  	ir.Syms.Asanwrite = typecheck.LookupRuntimeFunc("asanwrite")
   128  	ir.Syms.Newobject = typecheck.LookupRuntimeFunc("newobject")
   129  	ir.Syms.Newproc = typecheck.LookupRuntimeFunc("newproc")
   130  	ir.Syms.Panicdivide = typecheck.LookupRuntimeFunc("panicdivide")
   131  	ir.Syms.PanicdottypeE = typecheck.LookupRuntimeFunc("panicdottypeE")
   132  	ir.Syms.PanicdottypeI = typecheck.LookupRuntimeFunc("panicdottypeI")
   133  	ir.Syms.Panicnildottype = typecheck.LookupRuntimeFunc("panicnildottype")
   134  	ir.Syms.Panicoverflow = typecheck.LookupRuntimeFunc("panicoverflow")
   135  	ir.Syms.Panicshift = typecheck.LookupRuntimeFunc("panicshift")
   136  	ir.Syms.Racefuncenter = typecheck.LookupRuntimeFunc("racefuncenter")
   137  	ir.Syms.Racefuncexit = typecheck.LookupRuntimeFunc("racefuncexit")
   138  	ir.Syms.Raceread = typecheck.LookupRuntimeFunc("raceread")
   139  	ir.Syms.Racereadrange = typecheck.LookupRuntimeFunc("racereadrange")
   140  	ir.Syms.Racewrite = typecheck.LookupRuntimeFunc("racewrite")
   141  	ir.Syms.Racewriterange = typecheck.LookupRuntimeFunc("racewriterange")
   142  	ir.Syms.TypeAssert = typecheck.LookupRuntimeFunc("typeAssert")
   143  	ir.Syms.WBZero = typecheck.LookupRuntimeFunc("wbZero")
   144  	ir.Syms.WBMove = typecheck.LookupRuntimeFunc("wbMove")
   145  	ir.Syms.X86HasPOPCNT = typecheck.LookupRuntimeVar("x86HasPOPCNT")       // bool
   146  	ir.Syms.X86HasSSE41 = typecheck.LookupRuntimeVar("x86HasSSE41")         // bool
   147  	ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA")             // bool
   148  	ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4")         // bool
   149  	ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS") // bool
   150  	ir.Syms.Staticuint64s = typecheck.LookupRuntimeVar("staticuint64s")
   151  	ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
   152  	ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv")                 // asm func with special ABI
   153  	ir.Syms.WriteBarrier = typecheck.LookupRuntimeVar("writeBarrier") // struct { bool; ... }
   154  	ir.Syms.Zerobase = typecheck.LookupRuntimeVar("zerobase")
   155  
   156  	if Arch.LinkArch.Family == sys.Wasm {
   157  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("goPanicIndex")
   158  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("goPanicIndexU")
   159  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("goPanicSliceAlen")
   160  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("goPanicSliceAlenU")
   161  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("goPanicSliceAcap")
   162  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("goPanicSliceAcapU")
   163  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("goPanicSliceB")
   164  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("goPanicSliceBU")
   165  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("goPanicSlice3Alen")
   166  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("goPanicSlice3AlenU")
   167  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("goPanicSlice3Acap")
   168  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("goPanicSlice3AcapU")
   169  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("goPanicSlice3B")
   170  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
   171  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
   172  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
   173  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("goPanicSliceConvert")
   174  	} else {
   175  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("panicIndex")
   176  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("panicIndexU")
   177  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("panicSliceAlen")
   178  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("panicSliceAlenU")
   179  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("panicSliceAcap")
   180  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("panicSliceAcapU")
   181  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("panicSliceB")
   182  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("panicSliceBU")
   183  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("panicSlice3Alen")
   184  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("panicSlice3AlenU")
   185  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("panicSlice3Acap")
   186  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("panicSlice3AcapU")
   187  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("panicSlice3B")
   188  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("panicSlice3BU")
   189  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("panicSlice3C")
   190  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("panicSlice3CU")
   191  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("panicSliceConvert")
   192  	}
   193  	if Arch.LinkArch.PtrSize == 4 {
   194  		ExtendCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeVar("panicExtendIndex")
   195  		ExtendCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeVar("panicExtendIndexU")
   196  		ExtendCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeVar("panicExtendSliceAlen")
   197  		ExtendCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeVar("panicExtendSliceAlenU")
   198  		ExtendCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeVar("panicExtendSliceAcap")
   199  		ExtendCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeVar("panicExtendSliceAcapU")
   200  		ExtendCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeVar("panicExtendSliceB")
   201  		ExtendCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeVar("panicExtendSliceBU")
   202  		ExtendCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeVar("panicExtendSlice3Alen")
   203  		ExtendCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeVar("panicExtendSlice3AlenU")
   204  		ExtendCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeVar("panicExtendSlice3Acap")
   205  		ExtendCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeVar("panicExtendSlice3AcapU")
   206  		ExtendCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeVar("panicExtendSlice3B")
   207  		ExtendCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeVar("panicExtendSlice3BU")
   208  		ExtendCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeVar("panicExtendSlice3C")
   209  		ExtendCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeVar("panicExtendSlice3CU")
   210  	}
   211  
   212  	// Wasm (all asm funcs with special ABIs)
   213  	ir.Syms.WasmDiv = typecheck.LookupRuntimeVar("wasmDiv")
   214  	ir.Syms.WasmTruncS = typecheck.LookupRuntimeVar("wasmTruncS")
   215  	ir.Syms.WasmTruncU = typecheck.LookupRuntimeVar("wasmTruncU")
   216  	ir.Syms.SigPanic = typecheck.LookupRuntimeFunc("sigpanic")
   217  }
   218  
   219  // AbiForBodylessFuncStackMap returns the ABI for a bodyless function's stack map.
   220  // This is not necessarily the ABI used to call it.
   221  // Currently (1.17 dev) such a stack map is always ABI0;
   222  // any ABI wrapper that is present is nosplit, hence a precise
   223  // stack map is not needed there (the parameters survive only long
   224  // enough to call the wrapped assembly function).
   225  // This always returns a freshly copied ABI.
   226  func AbiForBodylessFuncStackMap(fn *ir.Func) *abi.ABIConfig {
   227  	return ssaConfig.ABI0.Copy() // No idea what races will result, be safe
   228  }
   229  
   230  // abiForFunc implements ABI policy for a function, but does not return a copy of the ABI.
   231  // Passing a nil function returns the default ABI based on experiment configuration.
   232  func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
   233  	if buildcfg.Experiment.RegabiArgs {
   234  		// Select the ABI based on the function's defining ABI.
   235  		if fn == nil {
   236  			return abi1
   237  		}
   238  		switch fn.ABI {
   239  		case obj.ABI0:
   240  			return abi0
   241  		case obj.ABIInternal:
   242  			// TODO(austin): Clean up the nomenclature here.
   243  			// It's not clear that "abi1" is ABIInternal.
   244  			return abi1
   245  		}
   246  		base.Fatalf("function %v has unknown ABI %v", fn, fn.ABI)
   247  		panic("not reachable")
   248  	}
   249  
   250  	a := abi0
   251  	if fn != nil {
   252  		if fn.Pragma&ir.RegisterParams != 0 { // TODO(register args) remove after register abi is working
   253  			a = abi1
   254  		}
   255  	}
   256  	return a
   257  }
   258  
   259  // emitOpenDeferInfo emits FUNCDATA information about the defers in a function
   260  // that is using open-coded defers.  This funcdata is used to determine the active
   261  // defers in a function and execute those defers during panic processing.
   262  //
   263  // The funcdata is all encoded in varints (since values will almost always be less than
   264  // 128, but stack offsets could potentially be up to 2Gbyte). All "locations" (offsets)
   265  // for stack variables are specified as the number of bytes below varp (pointer to the
   266  // top of the local variables) for their starting address. The format is:
   267  //
   268  //   - Offset of the deferBits variable
   269  //   - Offset of the first closure slot (the rest are laid out consecutively).
   270  func (s *state) emitOpenDeferInfo() {
   271  	firstOffset := s.openDefers[0].closureNode.FrameOffset()
   272  
   273  	// Verify that cmpstackvarlt laid out the slots in order.
   274  	for i, r := range s.openDefers {
   275  		have := r.closureNode.FrameOffset()
   276  		want := firstOffset + int64(i)*int64(types.PtrSize)
   277  		if have != want {
   278  			base.FatalfAt(s.curfn.Pos(), "unexpected frame offset for open-coded defer slot #%v: have %v, want %v", i, have, want)
   279  		}
   280  	}
   281  
   282  	x := base.Ctxt.Lookup(s.curfn.LSym.Name + ".opendefer")
   283  	x.Set(obj.AttrContentAddressable, true)
   284  	s.curfn.LSym.Func().OpenCodedDeferInfo = x
   285  
   286  	off := 0
   287  	off = objw.Uvarint(x, off, uint64(-s.deferBitsTemp.FrameOffset()))
   288  	off = objw.Uvarint(x, off, uint64(-firstOffset))
   289  }
   290  
   291  // buildssa builds an SSA function for fn.
   292  // worker indicates which of the backend workers is doing the processing.
   293  func buildssa(fn *ir.Func, worker int) *ssa.Func {
   294  	name := ir.FuncName(fn)
   295  
   296  	abiSelf := abiForFunc(fn, ssaConfig.ABI0, ssaConfig.ABI1)
   297  
   298  	printssa := false
   299  	// match either a simple name e.g. "(*Reader).Reset", package.name e.g. "compress/gzip.(*Reader).Reset", or subpackage name "gzip.(*Reader).Reset"
   300  	// optionally allows an ABI suffix specification in the GOSSAHASH, e.g. "(*Reader).Reset<0>" etc
   301  	if strings.Contains(ssaDump, name) { // in all the cases the function name is entirely contained within the GOSSAFUNC string.
   302  		nameOptABI := name
   303  		if strings.Contains(ssaDump, ",") { // ABI specification
   304  			nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   305  		} else if strings.HasSuffix(ssaDump, ">") { // if they use the linker syntax instead....
   306  			l := len(ssaDump)
   307  			if l >= 3 && ssaDump[l-3] == '<' {
   308  				nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   309  				ssaDump = ssaDump[:l-3] + "," + ssaDump[l-2:l-1]
   310  			}
   311  		}
   312  		pkgDotName := base.Ctxt.Pkgpath + "." + nameOptABI
   313  		printssa = nameOptABI == ssaDump || // "(*Reader).Reset"
   314  			pkgDotName == ssaDump || // "compress/gzip.(*Reader).Reset"
   315  			strings.HasSuffix(pkgDotName, ssaDump) && strings.HasSuffix(pkgDotName, "/"+ssaDump) // "gzip.(*Reader).Reset"
   316  	}
   317  
   318  	var astBuf *bytes.Buffer
   319  	if printssa {
   320  		astBuf = &bytes.Buffer{}
   321  		ir.FDumpList(astBuf, "buildssa-body", fn.Body)
   322  		if ssaDumpStdout {
   323  			fmt.Println("generating SSA for", name)
   324  			fmt.Print(astBuf.String())
   325  		}
   326  	}
   327  
   328  	var s state
   329  	s.pushLine(fn.Pos())
   330  	defer s.popLine()
   331  
   332  	s.hasdefer = fn.HasDefer()
   333  	if fn.Pragma&ir.CgoUnsafeArgs != 0 {
   334  		s.cgoUnsafeArgs = true
   335  	}
   336  	s.checkPtrEnabled = ir.ShouldCheckPtr(fn, 1)
   337  
   338  	if base.Flag.Cfg.Instrumenting && fn.Pragma&ir.Norace == 0 && !fn.Linksym().ABIWrapper() {
   339  		if !base.Flag.Race || !objabi.LookupPkgSpecial(fn.Sym().Pkg.Path).NoRaceFunc {
   340  			s.instrumentMemory = true
   341  		}
   342  		if base.Flag.Race {
   343  			s.instrumentEnterExit = true
   344  		}
   345  	}
   346  
   347  	fe := ssafn{
   348  		curfn: fn,
   349  		log:   printssa && ssaDumpStdout,
   350  	}
   351  	s.curfn = fn
   352  
   353  	cache := &ssaCaches[worker]
   354  	cache.Reset()
   355  
   356  	s.f = ssaConfig.NewFunc(&fe, cache)
   357  	s.config = ssaConfig
   358  	s.f.Type = fn.Type()
   359  	s.f.Name = name
   360  	s.f.PrintOrHtmlSSA = printssa
   361  	if fn.Pragma&ir.Nosplit != 0 {
   362  		s.f.NoSplit = true
   363  	}
   364  	s.f.ABI0 = ssaConfig.ABI0
   365  	s.f.ABI1 = ssaConfig.ABI1
   366  	s.f.ABIDefault = abiForFunc(nil, ssaConfig.ABI0, ssaConfig.ABI1)
   367  	s.f.ABISelf = abiSelf
   368  
   369  	s.panics = map[funcLine]*ssa.Block{}
   370  	s.softFloat = s.config.SoftFloat
   371  
   372  	// Allocate starting block
   373  	s.f.Entry = s.f.NewBlock(ssa.BlockPlain)
   374  	s.f.Entry.Pos = fn.Pos()
   375  
   376  	if printssa {
   377  		ssaDF := ssaDumpFile
   378  		if ssaDir != "" {
   379  			ssaDF = filepath.Join(ssaDir, base.Ctxt.Pkgpath+"."+s.f.NameABI()+".html")
   380  			ssaD := filepath.Dir(ssaDF)
   381  			os.MkdirAll(ssaD, 0755)
   382  		}
   383  		s.f.HTMLWriter = ssa.NewHTMLWriter(ssaDF, s.f, ssaDumpCFG)
   384  		// TODO: generate and print a mapping from nodes to values and blocks
   385  		dumpSourcesColumn(s.f.HTMLWriter, fn)
   386  		s.f.HTMLWriter.WriteAST("AST", astBuf)
   387  	}
   388  
   389  	// Allocate starting values
   390  	s.labels = map[string]*ssaLabel{}
   391  	s.fwdVars = map[ir.Node]*ssa.Value{}
   392  	s.startmem = s.entryNewValue0(ssa.OpInitMem, types.TypeMem)
   393  
   394  	s.hasOpenDefers = base.Flag.N == 0 && s.hasdefer && !s.curfn.OpenCodedDeferDisallowed()
   395  	switch {
   396  	case base.Debug.NoOpenDefer != 0:
   397  		s.hasOpenDefers = false
   398  	case s.hasOpenDefers && (base.Ctxt.Flag_shared || base.Ctxt.Flag_dynlink) && base.Ctxt.Arch.Name == "386":
   399  		// Don't support open-coded defers for 386 ONLY when using shared
   400  		// libraries, because there is extra code (added by rewriteToUseGot())
   401  		// preceding the deferreturn/ret code that we don't track correctly.
   402  		s.hasOpenDefers = false
   403  	}
   404  	if s.hasOpenDefers && s.instrumentEnterExit {
   405  		// Skip doing open defers if we need to instrument function
   406  		// returns for the race detector, since we will not generate that
   407  		// code in the case of the extra deferreturn/ret segment.
   408  		s.hasOpenDefers = false
   409  	}
   410  	if s.hasOpenDefers {
   411  		// Similarly, skip if there are any heap-allocated result
   412  		// parameters that need to be copied back to their stack slots.
   413  		for _, f := range s.curfn.Type().Results() {
   414  			if !f.Nname.(*ir.Name).OnStack() {
   415  				s.hasOpenDefers = false
   416  				break
   417  			}
   418  		}
   419  	}
   420  	if s.hasOpenDefers &&
   421  		s.curfn.NumReturns*s.curfn.NumDefers > 15 {
   422  		// Since we are generating defer calls at every exit for
   423  		// open-coded defers, skip doing open-coded defers if there are
   424  		// too many returns (especially if there are multiple defers).
   425  		// Open-coded defers are most important for improving performance
   426  		// for smaller functions (which don't have many returns).
   427  		s.hasOpenDefers = false
   428  	}
   429  
   430  	s.sp = s.entryNewValue0(ssa.OpSP, types.Types[types.TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
   431  	s.sb = s.entryNewValue0(ssa.OpSB, types.Types[types.TUINTPTR])
   432  
   433  	s.startBlock(s.f.Entry)
   434  	s.vars[memVar] = s.startmem
   435  	if s.hasOpenDefers {
   436  		// Create the deferBits variable and stack slot.  deferBits is a
   437  		// bitmask showing which of the open-coded defers in this function
   438  		// have been activated.
   439  		deferBitsTemp := typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
   440  		deferBitsTemp.SetAddrtaken(true)
   441  		s.deferBitsTemp = deferBitsTemp
   442  		// For this value, AuxInt is initialized to zero by default
   443  		startDeferBits := s.entryNewValue0(ssa.OpConst8, types.Types[types.TUINT8])
   444  		s.vars[deferBitsVar] = startDeferBits
   445  		s.deferBitsAddr = s.addr(deferBitsTemp)
   446  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, startDeferBits)
   447  		// Make sure that the deferBits stack slot is kept alive (for use
   448  		// by panics) and stores to deferBits are not eliminated, even if
   449  		// all checking code on deferBits in the function exit can be
   450  		// eliminated, because the defer statements were all
   451  		// unconditional.
   452  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, deferBitsTemp, s.mem(), false)
   453  	}
   454  
   455  	var params *abi.ABIParamResultInfo
   456  	params = s.f.ABISelf.ABIAnalyze(fn.Type(), true)
   457  
   458  	// The backend's stackframe pass prunes away entries from the fn's
   459  	// Dcl list, including PARAMOUT nodes that correspond to output
   460  	// params passed in registers. Walk the Dcl list and capture these
   461  	// nodes to a side list, so that we'll have them available during
   462  	// DWARF-gen later on. See issue 48573 for more details.
   463  	var debugInfo ssa.FuncDebug
   464  	for _, n := range fn.Dcl {
   465  		if n.Class == ir.PPARAMOUT && n.IsOutputParamInRegisters() {
   466  			debugInfo.RegOutputParams = append(debugInfo.RegOutputParams, n)
   467  		}
   468  	}
   469  	fn.DebugInfo = &debugInfo
   470  
   471  	// Generate addresses of local declarations
   472  	s.decladdrs = map[*ir.Name]*ssa.Value{}
   473  	for _, n := range fn.Dcl {
   474  		switch n.Class {
   475  		case ir.PPARAM:
   476  			// Be aware that blank and unnamed input parameters will not appear here, but do appear in the type
   477  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   478  		case ir.PPARAMOUT:
   479  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   480  		case ir.PAUTO:
   481  			// processed at each use, to prevent Addr coming
   482  			// before the decl.
   483  		default:
   484  			s.Fatalf("local variable with class %v unimplemented", n.Class)
   485  		}
   486  	}
   487  
   488  	s.f.OwnAux = ssa.OwnAuxCall(fn.LSym, params)
   489  
   490  	// Populate SSAable arguments.
   491  	for _, n := range fn.Dcl {
   492  		if n.Class == ir.PPARAM {
   493  			if s.canSSA(n) {
   494  				v := s.newValue0A(ssa.OpArg, n.Type(), n)
   495  				s.vars[n] = v
   496  				s.addNamedValue(n, v) // This helps with debugging information, not needed for compilation itself.
   497  			} else { // address was taken AND/OR too large for SSA
   498  				paramAssignment := ssa.ParamAssignmentForArgName(s.f, n)
   499  				if len(paramAssignment.Registers) > 0 {
   500  					if ssa.CanSSA(n.Type()) { // SSA-able type, so address was taken -- receive value in OpArg, DO NOT bind to var, store immediately to memory.
   501  						v := s.newValue0A(ssa.OpArg, n.Type(), n)
   502  						s.store(n.Type(), s.decladdrs[n], v)
   503  					} else { // Too big for SSA.
   504  						// Brute force, and early, do a bunch of stores from registers
   505  						// Note that expand calls knows about this and doesn't trouble itself with larger-than-SSA-able Args in registers.
   506  						s.storeParameterRegsToStack(s.f.ABISelf, paramAssignment, n, s.decladdrs[n], false)
   507  					}
   508  				}
   509  			}
   510  		}
   511  	}
   512  
   513  	// Populate closure variables.
   514  	if fn.Needctxt() {
   515  		clo := s.entryNewValue0(ssa.OpGetClosurePtr, s.f.Config.Types.BytePtr)
   516  		offset := int64(types.PtrSize) // PtrSize to skip past function entry PC field
   517  		for _, n := range fn.ClosureVars {
   518  			typ := n.Type()
   519  			if !n.Byval() {
   520  				typ = types.NewPtr(typ)
   521  			}
   522  
   523  			offset = types.RoundUp(offset, typ.Alignment())
   524  			ptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(typ), offset, clo)
   525  			offset += typ.Size()
   526  
   527  			// If n is a small variable captured by value, promote
   528  			// it to PAUTO so it can be converted to SSA.
   529  			//
   530  			// Note: While we never capture a variable by value if
   531  			// the user took its address, we may have generated
   532  			// runtime calls that did (#43701). Since we don't
   533  			// convert Addrtaken variables to SSA anyway, no point
   534  			// in promoting them either.
   535  			if n.Byval() && !n.Addrtaken() && ssa.CanSSA(n.Type()) {
   536  				n.Class = ir.PAUTO
   537  				fn.Dcl = append(fn.Dcl, n)
   538  				s.assign(n, s.load(n.Type(), ptr), false, 0)
   539  				continue
   540  			}
   541  
   542  			if !n.Byval() {
   543  				ptr = s.load(typ, ptr)
   544  			}
   545  			s.setHeapaddr(fn.Pos(), n, ptr)
   546  		}
   547  	}
   548  
   549  	// Convert the AST-based IR to the SSA-based IR
   550  	if s.instrumentEnterExit {
   551  		s.rtcall(ir.Syms.Racefuncenter, true, nil, s.newValue0(ssa.OpGetCallerPC, types.Types[types.TUINTPTR]))
   552  	}
   553  	s.zeroResults()
   554  	s.paramsToHeap()
   555  	s.stmtList(fn.Body)
   556  
   557  	// fallthrough to exit
   558  	if s.curBlock != nil {
   559  		s.pushLine(fn.Endlineno)
   560  		s.exit()
   561  		s.popLine()
   562  	}
   563  
   564  	for _, b := range s.f.Blocks {
   565  		if b.Pos != src.NoXPos {
   566  			s.updateUnsetPredPos(b)
   567  		}
   568  	}
   569  
   570  	s.f.HTMLWriter.WritePhase("before insert phis", "before insert phis")
   571  
   572  	s.insertPhis()
   573  
   574  	// Main call to ssa package to compile function
   575  	ssa.Compile(s.f)
   576  
   577  	fe.AllocFrame(s.f)
   578  
   579  	if len(s.openDefers) != 0 {
   580  		s.emitOpenDeferInfo()
   581  	}
   582  
   583  	// Record incoming parameter spill information for morestack calls emitted in the assembler.
   584  	// This is done here, using all the parameters (used, partially used, and unused) because
   585  	// it mimics the behavior of the former ABI (everything stored) and because it's not 100%
   586  	// clear if naming conventions are respected in autogenerated code.
   587  	// TODO figure out exactly what's unused, don't spill it. Make liveness fine-grained, also.
   588  	for _, p := range params.InParams() {
   589  		typs, offs := p.RegisterTypesAndOffsets()
   590  		for i, t := range typs {
   591  			o := offs[i]                // offset within parameter
   592  			fo := p.FrameOffset(params) // offset of parameter in frame
   593  			reg := ssa.ObjRegForAbiReg(p.Registers[i], s.f.Config)
   594  			s.f.RegArgs = append(s.f.RegArgs, ssa.Spill{Reg: reg, Offset: fo + o, Type: t})
   595  		}
   596  	}
   597  
   598  	return s.f
   599  }
   600  
   601  func (s *state) storeParameterRegsToStack(abi *abi.ABIConfig, paramAssignment *abi.ABIParamAssignment, n *ir.Name, addr *ssa.Value, pointersOnly bool) {
   602  	typs, offs := paramAssignment.RegisterTypesAndOffsets()
   603  	for i, t := range typs {
   604  		if pointersOnly && !t.IsPtrShaped() {
   605  			continue
   606  		}
   607  		r := paramAssignment.Registers[i]
   608  		o := offs[i]
   609  		op, reg := ssa.ArgOpAndRegisterFor(r, abi)
   610  		aux := &ssa.AuxNameOffset{Name: n, Offset: o}
   611  		v := s.newValue0I(op, t, reg)
   612  		v.Aux = aux
   613  		p := s.newValue1I(ssa.OpOffPtr, types.NewPtr(t), o, addr)
   614  		s.store(t, p, v)
   615  	}
   616  }
   617  
   618  // zeroResults zeros the return values at the start of the function.
   619  // We need to do this very early in the function.  Defer might stop a
   620  // panic and show the return values as they exist at the time of
   621  // panic.  For precise stacks, the garbage collector assumes results
   622  // are always live, so we need to zero them before any allocations,
   623  // even allocations to move params/results to the heap.
   624  func (s *state) zeroResults() {
   625  	for _, f := range s.curfn.Type().Results() {
   626  		n := f.Nname.(*ir.Name)
   627  		if !n.OnStack() {
   628  			// The local which points to the return value is the
   629  			// thing that needs zeroing. This is already handled
   630  			// by a Needzero annotation in plive.go:(*liveness).epilogue.
   631  			continue
   632  		}
   633  		// Zero the stack location containing f.
   634  		if typ := n.Type(); ssa.CanSSA(typ) {
   635  			s.assign(n, s.zeroVal(typ), false, 0)
   636  		} else {
   637  			if typ.HasPointers() {
   638  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
   639  			}
   640  			s.zero(n.Type(), s.decladdrs[n])
   641  		}
   642  	}
   643  }
   644  
   645  // paramsToHeap produces code to allocate memory for heap-escaped parameters
   646  // and to copy non-result parameters' values from the stack.
   647  func (s *state) paramsToHeap() {
   648  	do := func(params []*types.Field) {
   649  		for _, f := range params {
   650  			if f.Nname == nil {
   651  				continue // anonymous or blank parameter
   652  			}
   653  			n := f.Nname.(*ir.Name)
   654  			if ir.IsBlank(n) || n.OnStack() {
   655  				continue
   656  			}
   657  			s.newHeapaddr(n)
   658  			if n.Class == ir.PPARAM {
   659  				s.move(n.Type(), s.expr(n.Heapaddr), s.decladdrs[n])
   660  			}
   661  		}
   662  	}
   663  
   664  	typ := s.curfn.Type()
   665  	do(typ.Recvs())
   666  	do(typ.Params())
   667  	do(typ.Results())
   668  }
   669  
   670  // newHeapaddr allocates heap memory for n and sets its heap address.
   671  func (s *state) newHeapaddr(n *ir.Name) {
   672  	s.setHeapaddr(n.Pos(), n, s.newObject(n.Type(), nil))
   673  }
   674  
   675  // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
   676  // and then sets it as n's heap address.
   677  func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
   678  	if !ptr.Type.IsPtr() || !types.Identical(n.Type(), ptr.Type.Elem()) {
   679  		base.FatalfAt(n.Pos(), "setHeapaddr %L with type %v", n, ptr.Type)
   680  	}
   681  
   682  	// Declare variable to hold address.
   683  	sym := &types.Sym{Name: "&" + n.Sym().Name, Pkg: types.LocalPkg}
   684  	addr := s.curfn.NewLocal(pos, sym, types.NewPtr(n.Type()))
   685  	addr.SetUsed(true)
   686  	types.CalcSize(addr.Type())
   687  
   688  	if n.Class == ir.PPARAMOUT {
   689  		addr.SetIsOutputParamHeapAddr(true)
   690  	}
   691  
   692  	n.Heapaddr = addr
   693  	s.assign(addr, ptr, false, 0)
   694  }
   695  
   696  // newObject returns an SSA value denoting new(typ).
   697  func (s *state) newObject(typ *types.Type, rtype *ssa.Value) *ssa.Value {
   698  	if typ.Size() == 0 {
   699  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   700  	}
   701  	if rtype == nil {
   702  		rtype = s.reflectType(typ)
   703  	}
   704  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   705  }
   706  
   707  func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value) {
   708  	if !n.Type().IsPtr() {
   709  		s.Fatalf("expected pointer type: %v", n.Type())
   710  	}
   711  	elem, rtypeExpr := n.Type().Elem(), n.ElemRType
   712  	if count != nil {
   713  		if !elem.IsArray() {
   714  			s.Fatalf("expected array type: %v", elem)
   715  		}
   716  		elem, rtypeExpr = elem.Elem(), n.ElemElemRType
   717  	}
   718  	size := elem.Size()
   719  	// Casting from larger type to smaller one is ok, so for smallest type, do nothing.
   720  	if elem.Alignment() == 1 && (size == 0 || size == 1 || count == nil) {
   721  		return
   722  	}
   723  	if count == nil {
   724  		count = s.constInt(types.Types[types.TUINTPTR], 1)
   725  	}
   726  	if count.Type.Size() != s.config.PtrSize {
   727  		s.Fatalf("expected count fit to a uintptr size, have: %d, want: %d", count.Type.Size(), s.config.PtrSize)
   728  	}
   729  	var rtype *ssa.Value
   730  	if rtypeExpr != nil {
   731  		rtype = s.expr(rtypeExpr)
   732  	} else {
   733  		rtype = s.reflectType(elem)
   734  	}
   735  	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, rtype, count)
   736  }
   737  
   738  // reflectType returns an SSA value representing a pointer to typ's
   739  // reflection type descriptor.
   740  func (s *state) reflectType(typ *types.Type) *ssa.Value {
   741  	// TODO(mdempsky): Make this Fatalf under Unified IR; frontend needs
   742  	// to supply RType expressions.
   743  	lsym := reflectdata.TypeLinksym(typ)
   744  	return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(types.Types[types.TUINT8]), lsym, s.sb)
   745  }
   746  
   747  func dumpSourcesColumn(writer *ssa.HTMLWriter, fn *ir.Func) {
   748  	// Read sources of target function fn.
   749  	fname := base.Ctxt.PosTable.Pos(fn.Pos()).Filename()
   750  	targetFn, err := readFuncLines(fname, fn.Pos().Line(), fn.Endlineno.Line())
   751  	if err != nil {
   752  		writer.Logf("cannot read sources for function %v: %v", fn, err)
   753  	}
   754  
   755  	// Read sources of inlined functions.
   756  	var inlFns []*ssa.FuncLines
   757  	for _, fi := range ssaDumpInlined {
   758  		elno := fi.Endlineno
   759  		fname := base.Ctxt.PosTable.Pos(fi.Pos()).Filename()
   760  		fnLines, err := readFuncLines(fname, fi.Pos().Line(), elno.Line())
   761  		if err != nil {
   762  			writer.Logf("cannot read sources for inlined function %v: %v", fi, err)
   763  			continue
   764  		}
   765  		inlFns = append(inlFns, fnLines)
   766  	}
   767  
   768  	sort.Sort(ssa.ByTopo(inlFns))
   769  	if targetFn != nil {
   770  		inlFns = append([]*ssa.FuncLines{targetFn}, inlFns...)
   771  	}
   772  
   773  	writer.WriteSources("sources", inlFns)
   774  }
   775  
   776  func readFuncLines(file string, start, end uint) (*ssa.FuncLines, error) {
   777  	f, err := os.Open(os.ExpandEnv(file))
   778  	if err != nil {
   779  		return nil, err
   780  	}
   781  	defer f.Close()
   782  	var lines []string
   783  	ln := uint(1)
   784  	scanner := bufio.NewScanner(f)
   785  	for scanner.Scan() && ln <= end {
   786  		if ln >= start {
   787  			lines = append(lines, scanner.Text())
   788  		}
   789  		ln++
   790  	}
   791  	return &ssa.FuncLines{Filename: file, StartLineno: start, Lines: lines}, nil
   792  }
   793  
   794  // updateUnsetPredPos propagates the earliest-value position information for b
   795  // towards all of b's predecessors that need a position, and recurs on that
   796  // predecessor if its position is updated. B should have a non-empty position.
   797  func (s *state) updateUnsetPredPos(b *ssa.Block) {
   798  	if b.Pos == src.NoXPos {
   799  		s.Fatalf("Block %s should have a position", b)
   800  	}
   801  	bestPos := src.NoXPos
   802  	for _, e := range b.Preds {
   803  		p := e.Block()
   804  		if !p.LackingPos() {
   805  			continue
   806  		}
   807  		if bestPos == src.NoXPos {
   808  			bestPos = b.Pos
   809  			for _, v := range b.Values {
   810  				if v.LackingPos() {
   811  					continue
   812  				}
   813  				if v.Pos != src.NoXPos {
   814  					// Assume values are still in roughly textual order;
   815  					// TODO: could also seek minimum position?
   816  					bestPos = v.Pos
   817  					break
   818  				}
   819  			}
   820  		}
   821  		p.Pos = bestPos
   822  		s.updateUnsetPredPos(p) // We do not expect long chains of these, thus recursion is okay.
   823  	}
   824  }
   825  
   826  // Information about each open-coded defer.
   827  type openDeferInfo struct {
   828  	// The node representing the call of the defer
   829  	n *ir.CallExpr
   830  	// If defer call is closure call, the address of the argtmp where the
   831  	// closure is stored.
   832  	closure *ssa.Value
   833  	// The node representing the argtmp where the closure is stored - used for
   834  	// function, method, or interface call, to store a closure that panic
   835  	// processing can use for this defer.
   836  	closureNode *ir.Name
   837  }
   838  
   839  type state struct {
   840  	// configuration (arch) information
   841  	config *ssa.Config
   842  
   843  	// function we're building
   844  	f *ssa.Func
   845  
   846  	// Node for function
   847  	curfn *ir.Func
   848  
   849  	// labels in f
   850  	labels map[string]*ssaLabel
   851  
   852  	// unlabeled break and continue statement tracking
   853  	breakTo    *ssa.Block // current target for plain break statement
   854  	continueTo *ssa.Block // current target for plain continue statement
   855  
   856  	// current location where we're interpreting the AST
   857  	curBlock *ssa.Block
   858  
   859  	// variable assignments in the current block (map from variable symbol to ssa value)
   860  	// *Node is the unique identifier (an ONAME Node) for the variable.
   861  	// TODO: keep a single varnum map, then make all of these maps slices instead?
   862  	vars map[ir.Node]*ssa.Value
   863  
   864  	// fwdVars are variables that are used before they are defined in the current block.
   865  	// This map exists just to coalesce multiple references into a single FwdRef op.
   866  	// *Node is the unique identifier (an ONAME Node) for the variable.
   867  	fwdVars map[ir.Node]*ssa.Value
   868  
   869  	// all defined variables at the end of each block. Indexed by block ID.
   870  	defvars []map[ir.Node]*ssa.Value
   871  
   872  	// addresses of PPARAM and PPARAMOUT variables on the stack.
   873  	decladdrs map[*ir.Name]*ssa.Value
   874  
   875  	// starting values. Memory, stack pointer, and globals pointer
   876  	startmem *ssa.Value
   877  	sp       *ssa.Value
   878  	sb       *ssa.Value
   879  	// value representing address of where deferBits autotmp is stored
   880  	deferBitsAddr *ssa.Value
   881  	deferBitsTemp *ir.Name
   882  
   883  	// line number stack. The current line number is top of stack
   884  	line []src.XPos
   885  	// the last line number processed; it may have been popped
   886  	lastPos src.XPos
   887  
   888  	// list of panic calls by function name and line number.
   889  	// Used to deduplicate panic calls.
   890  	panics map[funcLine]*ssa.Block
   891  
   892  	cgoUnsafeArgs       bool
   893  	hasdefer            bool // whether the function contains a defer statement
   894  	softFloat           bool
   895  	hasOpenDefers       bool // whether we are doing open-coded defers
   896  	checkPtrEnabled     bool // whether to insert checkptr instrumentation
   897  	instrumentEnterExit bool // whether to instrument function enter/exit
   898  	instrumentMemory    bool // whether to instrument memory operations
   899  
   900  	// If doing open-coded defers, list of info about the defer calls in
   901  	// scanning order. Hence, at exit we should run these defers in reverse
   902  	// order of this list
   903  	openDefers []*openDeferInfo
   904  	// For open-coded defers, this is the beginning and end blocks of the last
   905  	// defer exit code that we have generated so far. We use these to share
   906  	// code between exits if the shareDeferExits option (disabled by default)
   907  	// is on.
   908  	lastDeferExit       *ssa.Block // Entry block of last defer exit code we generated
   909  	lastDeferFinalBlock *ssa.Block // Final block of last defer exit code we generated
   910  	lastDeferCount      int        // Number of defers encountered at that point
   911  
   912  	prevCall *ssa.Value // the previous call; use this to tie results to the call op.
   913  }
   914  
   915  type funcLine struct {
   916  	f    *obj.LSym
   917  	base *src.PosBase
   918  	line uint
   919  }
   920  
   921  type ssaLabel struct {
   922  	target         *ssa.Block // block identified by this label
   923  	breakTarget    *ssa.Block // block to break to in control flow node identified by this label
   924  	continueTarget *ssa.Block // block to continue to in control flow node identified by this label
   925  }
   926  
   927  // label returns the label associated with sym, creating it if necessary.
   928  func (s *state) label(sym *types.Sym) *ssaLabel {
   929  	lab := s.labels[sym.Name]
   930  	if lab == nil {
   931  		lab = new(ssaLabel)
   932  		s.labels[sym.Name] = lab
   933  	}
   934  	return lab
   935  }
   936  
   937  func (s *state) Logf(msg string, args ...interface{}) { s.f.Logf(msg, args...) }
   938  func (s *state) Log() bool                            { return s.f.Log() }
   939  func (s *state) Fatalf(msg string, args ...interface{}) {
   940  	s.f.Frontend().Fatalf(s.peekPos(), msg, args...)
   941  }
   942  func (s *state) Warnl(pos src.XPos, msg string, args ...interface{}) { s.f.Warnl(pos, msg, args...) }
   943  func (s *state) Debug_checknil() bool                                { return s.f.Frontend().Debug_checknil() }
   944  
   945  func ssaMarker(name string) *ir.Name {
   946  	return ir.NewNameAt(base.Pos, &types.Sym{Name: name}, nil)
   947  }
   948  
   949  var (
   950  	// marker node for the memory variable
   951  	memVar = ssaMarker("mem")
   952  
   953  	// marker nodes for temporary variables
   954  	ptrVar       = ssaMarker("ptr")
   955  	lenVar       = ssaMarker("len")
   956  	capVar       = ssaMarker("cap")
   957  	typVar       = ssaMarker("typ")
   958  	okVar        = ssaMarker("ok")
   959  	deferBitsVar = ssaMarker("deferBits")
   960  	hashVar      = ssaMarker("hash")
   961  )
   962  
   963  // startBlock sets the current block we're generating code in to b.
   964  func (s *state) startBlock(b *ssa.Block) {
   965  	if s.curBlock != nil {
   966  		s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
   967  	}
   968  	s.curBlock = b
   969  	s.vars = map[ir.Node]*ssa.Value{}
   970  	for n := range s.fwdVars {
   971  		delete(s.fwdVars, n)
   972  	}
   973  }
   974  
   975  // endBlock marks the end of generating code for the current block.
   976  // Returns the (former) current block. Returns nil if there is no current
   977  // block, i.e. if no code flows to the current execution point.
   978  func (s *state) endBlock() *ssa.Block {
   979  	b := s.curBlock
   980  	if b == nil {
   981  		return nil
   982  	}
   983  	for len(s.defvars) <= int(b.ID) {
   984  		s.defvars = append(s.defvars, nil)
   985  	}
   986  	s.defvars[b.ID] = s.vars
   987  	s.curBlock = nil
   988  	s.vars = nil
   989  	if b.LackingPos() {
   990  		// Empty plain blocks get the line of their successor (handled after all blocks created),
   991  		// except for increment blocks in For statements (handled in ssa conversion of OFOR),
   992  		// and for blocks ending in GOTO/BREAK/CONTINUE.
   993  		b.Pos = src.NoXPos
   994  	} else {
   995  		b.Pos = s.lastPos
   996  	}
   997  	return b
   998  }
   999  
  1000  // pushLine pushes a line number on the line number stack.
  1001  func (s *state) pushLine(line src.XPos) {
  1002  	if !line.IsKnown() {
  1003  		// the frontend may emit node with line number missing,
  1004  		// use the parent line number in this case.
  1005  		line = s.peekPos()
  1006  		if base.Flag.K != 0 {
  1007  			base.Warn("buildssa: unknown position (line 0)")
  1008  		}
  1009  	} else {
  1010  		s.lastPos = line
  1011  	}
  1012  
  1013  	s.line = append(s.line, line)
  1014  }
  1015  
  1016  // popLine pops the top of the line number stack.
  1017  func (s *state) popLine() {
  1018  	s.line = s.line[:len(s.line)-1]
  1019  }
  1020  
  1021  // peekPos peeks the top of the line number stack.
  1022  func (s *state) peekPos() src.XPos {
  1023  	return s.line[len(s.line)-1]
  1024  }
  1025  
  1026  // newValue0 adds a new value with no arguments to the current block.
  1027  func (s *state) newValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1028  	return s.curBlock.NewValue0(s.peekPos(), op, t)
  1029  }
  1030  
  1031  // newValue0A adds a new value with no arguments and an aux value to the current block.
  1032  func (s *state) newValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1033  	return s.curBlock.NewValue0A(s.peekPos(), op, t, aux)
  1034  }
  1035  
  1036  // newValue0I adds a new value with no arguments and an auxint value to the current block.
  1037  func (s *state) newValue0I(op ssa.Op, t *types.Type, auxint int64) *ssa.Value {
  1038  	return s.curBlock.NewValue0I(s.peekPos(), op, t, auxint)
  1039  }
  1040  
  1041  // newValue1 adds a new value with one argument to the current block.
  1042  func (s *state) newValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1043  	return s.curBlock.NewValue1(s.peekPos(), op, t, arg)
  1044  }
  1045  
  1046  // newValue1A adds a new value with one argument and an aux value to the current block.
  1047  func (s *state) newValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1048  	return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1049  }
  1050  
  1051  // newValue1Apos adds a new value with one argument and an aux value to the current block.
  1052  // isStmt determines whether the created values may be a statement or not
  1053  // (i.e., false means never, yes means maybe).
  1054  func (s *state) newValue1Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value, isStmt bool) *ssa.Value {
  1055  	if isStmt {
  1056  		return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1057  	}
  1058  	return s.curBlock.NewValue1A(s.peekPos().WithNotStmt(), op, t, aux, arg)
  1059  }
  1060  
  1061  // newValue1I adds a new value with one argument and an auxint value to the current block.
  1062  func (s *state) newValue1I(op ssa.Op, t *types.Type, aux int64, arg *ssa.Value) *ssa.Value {
  1063  	return s.curBlock.NewValue1I(s.peekPos(), op, t, aux, arg)
  1064  }
  1065  
  1066  // newValue2 adds a new value with two arguments to the current block.
  1067  func (s *state) newValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1068  	return s.curBlock.NewValue2(s.peekPos(), op, t, arg0, arg1)
  1069  }
  1070  
  1071  // newValue2A adds a new value with two arguments and an aux value to the current block.
  1072  func (s *state) newValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1073  	return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1074  }
  1075  
  1076  // newValue2Apos adds a new value with two arguments and an aux value to the current block.
  1077  // isStmt determines whether the created values may be a statement or not
  1078  // (i.e., false means never, yes means maybe).
  1079  func (s *state) newValue2Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value, isStmt bool) *ssa.Value {
  1080  	if isStmt {
  1081  		return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1082  	}
  1083  	return s.curBlock.NewValue2A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1)
  1084  }
  1085  
  1086  // newValue2I adds a new value with two arguments and an auxint value to the current block.
  1087  func (s *state) newValue2I(op ssa.Op, t *types.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
  1088  	return s.curBlock.NewValue2I(s.peekPos(), op, t, aux, arg0, arg1)
  1089  }
  1090  
  1091  // newValue3 adds a new value with three arguments to the current block.
  1092  func (s *state) newValue3(op ssa.Op, t *types.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1093  	return s.curBlock.NewValue3(s.peekPos(), op, t, arg0, arg1, arg2)
  1094  }
  1095  
  1096  // newValue3I adds a new value with three arguments and an auxint value to the current block.
  1097  func (s *state) newValue3I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1098  	return s.curBlock.NewValue3I(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1099  }
  1100  
  1101  // newValue3A adds a new value with three arguments and an aux value to the current block.
  1102  func (s *state) newValue3A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1103  	return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1104  }
  1105  
  1106  // newValue3Apos adds a new value with three arguments and an aux value to the current block.
  1107  // isStmt determines whether the created values may be a statement or not
  1108  // (i.e., false means never, yes means maybe).
  1109  func (s *state) newValue3Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value, isStmt bool) *ssa.Value {
  1110  	if isStmt {
  1111  		return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1112  	}
  1113  	return s.curBlock.NewValue3A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1, arg2)
  1114  }
  1115  
  1116  // newValue4 adds a new value with four arguments to the current block.
  1117  func (s *state) newValue4(op ssa.Op, t *types.Type, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1118  	return s.curBlock.NewValue4(s.peekPos(), op, t, arg0, arg1, arg2, arg3)
  1119  }
  1120  
  1121  // newValue4I adds a new value with four arguments and an auxint value to the current block.
  1122  func (s *state) newValue4I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1123  	return s.curBlock.NewValue4I(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1124  }
  1125  
  1126  func (s *state) entryBlock() *ssa.Block {
  1127  	b := s.f.Entry
  1128  	if base.Flag.N > 0 && s.curBlock != nil {
  1129  		// If optimizations are off, allocate in current block instead. Since with -N
  1130  		// we're not doing the CSE or tighten passes, putting lots of stuff in the
  1131  		// entry block leads to O(n^2) entries in the live value map during regalloc.
  1132  		// See issue 45897.
  1133  		b = s.curBlock
  1134  	}
  1135  	return b
  1136  }
  1137  
  1138  // entryNewValue0 adds a new value with no arguments to the entry block.
  1139  func (s *state) entryNewValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1140  	return s.entryBlock().NewValue0(src.NoXPos, op, t)
  1141  }
  1142  
  1143  // entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
  1144  func (s *state) entryNewValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1145  	return s.entryBlock().NewValue0A(src.NoXPos, op, t, aux)
  1146  }
  1147  
  1148  // entryNewValue1 adds a new value with one argument to the entry block.
  1149  func (s *state) entryNewValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1150  	return s.entryBlock().NewValue1(src.NoXPos, op, t, arg)
  1151  }
  1152  
  1153  // entryNewValue1I adds a new value with one argument and an auxint value to the entry block.
  1154  func (s *state) entryNewValue1I(op ssa.Op, t *types.Type, auxint int64, arg *ssa.Value) *ssa.Value {
  1155  	return s.entryBlock().NewValue1I(src.NoXPos, op, t, auxint, arg)
  1156  }
  1157  
  1158  // entryNewValue1A adds a new value with one argument and an aux value to the entry block.
  1159  func (s *state) entryNewValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1160  	return s.entryBlock().NewValue1A(src.NoXPos, op, t, aux, arg)
  1161  }
  1162  
  1163  // entryNewValue2 adds a new value with two arguments to the entry block.
  1164  func (s *state) entryNewValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1165  	return s.entryBlock().NewValue2(src.NoXPos, op, t, arg0, arg1)
  1166  }
  1167  
  1168  // entryNewValue2A adds a new value with two arguments and an aux value to the entry block.
  1169  func (s *state) entryNewValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1170  	return s.entryBlock().NewValue2A(src.NoXPos, op, t, aux, arg0, arg1)
  1171  }
  1172  
  1173  // const* routines add a new const value to the entry block.
  1174  func (s *state) constSlice(t *types.Type) *ssa.Value {
  1175  	return s.f.ConstSlice(t)
  1176  }
  1177  func (s *state) constInterface(t *types.Type) *ssa.Value {
  1178  	return s.f.ConstInterface(t)
  1179  }
  1180  func (s *state) constNil(t *types.Type) *ssa.Value { return s.f.ConstNil(t) }
  1181  func (s *state) constEmptyString(t *types.Type) *ssa.Value {
  1182  	return s.f.ConstEmptyString(t)
  1183  }
  1184  func (s *state) constBool(c bool) *ssa.Value {
  1185  	return s.f.ConstBool(types.Types[types.TBOOL], c)
  1186  }
  1187  func (s *state) constInt8(t *types.Type, c int8) *ssa.Value {
  1188  	return s.f.ConstInt8(t, c)
  1189  }
  1190  func (s *state) constInt16(t *types.Type, c int16) *ssa.Value {
  1191  	return s.f.ConstInt16(t, c)
  1192  }
  1193  func (s *state) constInt32(t *types.Type, c int32) *ssa.Value {
  1194  	return s.f.ConstInt32(t, c)
  1195  }
  1196  func (s *state) constInt64(t *types.Type, c int64) *ssa.Value {
  1197  	return s.f.ConstInt64(t, c)
  1198  }
  1199  func (s *state) constFloat32(t *types.Type, c float64) *ssa.Value {
  1200  	return s.f.ConstFloat32(t, c)
  1201  }
  1202  func (s *state) constFloat64(t *types.Type, c float64) *ssa.Value {
  1203  	return s.f.ConstFloat64(t, c)
  1204  }
  1205  func (s *state) constInt(t *types.Type, c int64) *ssa.Value {
  1206  	if s.config.PtrSize == 8 {
  1207  		return s.constInt64(t, c)
  1208  	}
  1209  	if int64(int32(c)) != c {
  1210  		s.Fatalf("integer constant too big %d", c)
  1211  	}
  1212  	return s.constInt32(t, int32(c))
  1213  }
  1214  func (s *state) constOffPtrSP(t *types.Type, c int64) *ssa.Value {
  1215  	return s.f.ConstOffPtrSP(t, c, s.sp)
  1216  }
  1217  
  1218  // newValueOrSfCall* are wrappers around newValue*, which may create a call to a
  1219  // soft-float runtime function instead (when emitting soft-float code).
  1220  func (s *state) newValueOrSfCall1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1221  	if s.softFloat {
  1222  		if c, ok := s.sfcall(op, arg); ok {
  1223  			return c
  1224  		}
  1225  	}
  1226  	return s.newValue1(op, t, arg)
  1227  }
  1228  func (s *state) newValueOrSfCall2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1229  	if s.softFloat {
  1230  		if c, ok := s.sfcall(op, arg0, arg1); ok {
  1231  			return c
  1232  		}
  1233  	}
  1234  	return s.newValue2(op, t, arg0, arg1)
  1235  }
  1236  
  1237  type instrumentKind uint8
  1238  
  1239  const (
  1240  	instrumentRead = iota
  1241  	instrumentWrite
  1242  	instrumentMove
  1243  )
  1244  
  1245  func (s *state) instrument(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1246  	s.instrument2(t, addr, nil, kind)
  1247  }
  1248  
  1249  // instrumentFields instruments a read/write operation on addr.
  1250  // If it is instrumenting for MSAN or ASAN and t is a struct type, it instruments
  1251  // operation for each field, instead of for the whole struct.
  1252  func (s *state) instrumentFields(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1253  	if !(base.Flag.MSan || base.Flag.ASan) || !t.IsStruct() {
  1254  		s.instrument(t, addr, kind)
  1255  		return
  1256  	}
  1257  	for _, f := range t.Fields() {
  1258  		if f.Sym.IsBlank() {
  1259  			continue
  1260  		}
  1261  		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), f.Offset, addr)
  1262  		s.instrumentFields(f.Type, offptr, kind)
  1263  	}
  1264  }
  1265  
  1266  func (s *state) instrumentMove(t *types.Type, dst, src *ssa.Value) {
  1267  	if base.Flag.MSan {
  1268  		s.instrument2(t, dst, src, instrumentMove)
  1269  	} else {
  1270  		s.instrument(t, src, instrumentRead)
  1271  		s.instrument(t, dst, instrumentWrite)
  1272  	}
  1273  }
  1274  
  1275  func (s *state) instrument2(t *types.Type, addr, addr2 *ssa.Value, kind instrumentKind) {
  1276  	if !s.instrumentMemory {
  1277  		return
  1278  	}
  1279  
  1280  	w := t.Size()
  1281  	if w == 0 {
  1282  		return // can't race on zero-sized things
  1283  	}
  1284  
  1285  	if ssa.IsSanitizerSafeAddr(addr) {
  1286  		return
  1287  	}
  1288  
  1289  	var fn *obj.LSym
  1290  	needWidth := false
  1291  
  1292  	if addr2 != nil && kind != instrumentMove {
  1293  		panic("instrument2: non-nil addr2 for non-move instrumentation")
  1294  	}
  1295  
  1296  	if base.Flag.MSan {
  1297  		switch kind {
  1298  		case instrumentRead:
  1299  			fn = ir.Syms.Msanread
  1300  		case instrumentWrite:
  1301  			fn = ir.Syms.Msanwrite
  1302  		case instrumentMove:
  1303  			fn = ir.Syms.Msanmove
  1304  		default:
  1305  			panic("unreachable")
  1306  		}
  1307  		needWidth = true
  1308  	} else if base.Flag.Race && t.NumComponents(types.CountBlankFields) > 1 {
  1309  		// for composite objects we have to write every address
  1310  		// because a write might happen to any subobject.
  1311  		// composites with only one element don't have subobjects, though.
  1312  		switch kind {
  1313  		case instrumentRead:
  1314  			fn = ir.Syms.Racereadrange
  1315  		case instrumentWrite:
  1316  			fn = ir.Syms.Racewriterange
  1317  		default:
  1318  			panic("unreachable")
  1319  		}
  1320  		needWidth = true
  1321  	} else if base.Flag.Race {
  1322  		// for non-composite objects we can write just the start
  1323  		// address, as any write must write the first byte.
  1324  		switch kind {
  1325  		case instrumentRead:
  1326  			fn = ir.Syms.Raceread
  1327  		case instrumentWrite:
  1328  			fn = ir.Syms.Racewrite
  1329  		default:
  1330  			panic("unreachable")
  1331  		}
  1332  	} else if base.Flag.ASan {
  1333  		switch kind {
  1334  		case instrumentRead:
  1335  			fn = ir.Syms.Asanread
  1336  		case instrumentWrite:
  1337  			fn = ir.Syms.Asanwrite
  1338  		default:
  1339  			panic("unreachable")
  1340  		}
  1341  		needWidth = true
  1342  	} else {
  1343  		panic("unreachable")
  1344  	}
  1345  
  1346  	args := []*ssa.Value{addr}
  1347  	if addr2 != nil {
  1348  		args = append(args, addr2)
  1349  	}
  1350  	if needWidth {
  1351  		args = append(args, s.constInt(types.Types[types.TUINTPTR], w))
  1352  	}
  1353  	s.rtcall(fn, true, nil, args...)
  1354  }
  1355  
  1356  func (s *state) load(t *types.Type, src *ssa.Value) *ssa.Value {
  1357  	s.instrumentFields(t, src, instrumentRead)
  1358  	return s.rawLoad(t, src)
  1359  }
  1360  
  1361  func (s *state) rawLoad(t *types.Type, src *ssa.Value) *ssa.Value {
  1362  	return s.newValue2(ssa.OpLoad, t, src, s.mem())
  1363  }
  1364  
  1365  func (s *state) store(t *types.Type, dst, val *ssa.Value) {
  1366  	s.vars[memVar] = s.newValue3A(ssa.OpStore, types.TypeMem, t, dst, val, s.mem())
  1367  }
  1368  
  1369  func (s *state) zero(t *types.Type, dst *ssa.Value) {
  1370  	s.instrument(t, dst, instrumentWrite)
  1371  	store := s.newValue2I(ssa.OpZero, types.TypeMem, t.Size(), dst, s.mem())
  1372  	store.Aux = t
  1373  	s.vars[memVar] = store
  1374  }
  1375  
  1376  func (s *state) move(t *types.Type, dst, src *ssa.Value) {
  1377  	s.moveWhichMayOverlap(t, dst, src, false)
  1378  }
  1379  func (s *state) moveWhichMayOverlap(t *types.Type, dst, src *ssa.Value, mayOverlap bool) {
  1380  	s.instrumentMove(t, dst, src)
  1381  	if mayOverlap && t.IsArray() && t.NumElem() > 1 && !ssa.IsInlinableMemmove(dst, src, t.Size(), s.f.Config) {
  1382  		// Normally, when moving Go values of type T from one location to another,
  1383  		// we don't need to worry about partial overlaps. The two Ts must either be
  1384  		// in disjoint (nonoverlapping) memory or in exactly the same location.
  1385  		// There are 2 cases where this isn't true:
  1386  		//  1) Using unsafe you can arrange partial overlaps.
  1387  		//  2) Since Go 1.17, you can use a cast from a slice to a ptr-to-array.
  1388  		//     https://go.dev/ref/spec#Conversions_from_slice_to_array_pointer
  1389  		//     This feature can be used to construct partial overlaps of array types.
  1390  		//       var a [3]int
  1391  		//       p := (*[2]int)(a[:])
  1392  		//       q := (*[2]int)(a[1:])
  1393  		//       *p = *q
  1394  		// We don't care about solving 1. Or at least, we haven't historically
  1395  		// and no one has complained.
  1396  		// For 2, we need to ensure that if there might be partial overlap,
  1397  		// then we can't use OpMove; we must use memmove instead.
  1398  		// (memmove handles partial overlap by copying in the correct
  1399  		// direction. OpMove does not.)
  1400  		//
  1401  		// Note that we have to be careful here not to introduce a call when
  1402  		// we're marshaling arguments to a call or unmarshaling results from a call.
  1403  		// Cases where this is happening must pass mayOverlap to false.
  1404  		// (Currently this only happens when unmarshaling results of a call.)
  1405  		if t.HasPointers() {
  1406  			s.rtcall(ir.Syms.Typedmemmove, true, nil, s.reflectType(t), dst, src)
  1407  			// We would have otherwise implemented this move with straightline code,
  1408  			// including a write barrier. Pretend we issue a write barrier here,
  1409  			// so that the write barrier tests work. (Otherwise they'd need to know
  1410  			// the details of IsInlineableMemmove.)
  1411  			s.curfn.SetWBPos(s.peekPos())
  1412  		} else {
  1413  			s.rtcall(ir.Syms.Memmove, true, nil, dst, src, s.constInt(types.Types[types.TUINTPTR], t.Size()))
  1414  		}
  1415  		ssa.LogLargeCopy(s.f.Name, s.peekPos(), t.Size())
  1416  		return
  1417  	}
  1418  	store := s.newValue3I(ssa.OpMove, types.TypeMem, t.Size(), dst, src, s.mem())
  1419  	store.Aux = t
  1420  	s.vars[memVar] = store
  1421  }
  1422  
  1423  // stmtList converts the statement list n to SSA and adds it to s.
  1424  func (s *state) stmtList(l ir.Nodes) {
  1425  	for _, n := range l {
  1426  		s.stmt(n)
  1427  	}
  1428  }
  1429  
  1430  // stmt converts the statement n to SSA and adds it to s.
  1431  func (s *state) stmt(n ir.Node) {
  1432  	s.pushLine(n.Pos())
  1433  	defer s.popLine()
  1434  
  1435  	// If s.curBlock is nil, and n isn't a label (which might have an associated goto somewhere),
  1436  	// then this code is dead. Stop here.
  1437  	if s.curBlock == nil && n.Op() != ir.OLABEL {
  1438  		return
  1439  	}
  1440  
  1441  	s.stmtList(n.Init())
  1442  	switch n.Op() {
  1443  
  1444  	case ir.OBLOCK:
  1445  		n := n.(*ir.BlockStmt)
  1446  		s.stmtList(n.List)
  1447  
  1448  	case ir.OFALL: // no-op
  1449  
  1450  	// Expression statements
  1451  	case ir.OCALLFUNC:
  1452  		n := n.(*ir.CallExpr)
  1453  		if ir.IsIntrinsicCall(n) {
  1454  			s.intrinsicCall(n)
  1455  			return
  1456  		}
  1457  		fallthrough
  1458  
  1459  	case ir.OCALLINTER:
  1460  		n := n.(*ir.CallExpr)
  1461  		s.callResult(n, callNormal)
  1462  		if n.Op() == ir.OCALLFUNC && n.Fun.Op() == ir.ONAME && n.Fun.(*ir.Name).Class == ir.PFUNC {
  1463  			if fn := n.Fun.Sym().Name; base.Flag.CompilingRuntime && fn == "throw" ||
  1464  				n.Fun.Sym().Pkg == ir.Pkgs.Runtime && (fn == "throwinit" || fn == "gopanic" || fn == "panicwrap" || fn == "block" || fn == "panicmakeslicelen" || fn == "panicmakeslicecap" || fn == "panicunsafeslicelen" || fn == "panicunsafeslicenilptr" || fn == "panicunsafestringlen" || fn == "panicunsafestringnilptr") {
  1465  				m := s.mem()
  1466  				b := s.endBlock()
  1467  				b.Kind = ssa.BlockExit
  1468  				b.SetControl(m)
  1469  				// TODO: never rewrite OPANIC to OCALLFUNC in the
  1470  				// first place. Need to wait until all backends
  1471  				// go through SSA.
  1472  			}
  1473  		}
  1474  	case ir.ODEFER:
  1475  		n := n.(*ir.GoDeferStmt)
  1476  		if base.Debug.Defer > 0 {
  1477  			var defertype string
  1478  			if s.hasOpenDefers {
  1479  				defertype = "open-coded"
  1480  			} else if n.Esc() == ir.EscNever {
  1481  				defertype = "stack-allocated"
  1482  			} else {
  1483  				defertype = "heap-allocated"
  1484  			}
  1485  			base.WarnfAt(n.Pos(), "%s defer", defertype)
  1486  		}
  1487  		if s.hasOpenDefers {
  1488  			s.openDeferRecord(n.Call.(*ir.CallExpr))
  1489  		} else {
  1490  			d := callDefer
  1491  			if n.Esc() == ir.EscNever && n.DeferAt == nil {
  1492  				d = callDeferStack
  1493  			}
  1494  			s.call(n.Call.(*ir.CallExpr), d, false, n.DeferAt)
  1495  		}
  1496  	case ir.OGO:
  1497  		n := n.(*ir.GoDeferStmt)
  1498  		s.callResult(n.Call.(*ir.CallExpr), callGo)
  1499  
  1500  	case ir.OAS2DOTTYPE:
  1501  		n := n.(*ir.AssignListStmt)
  1502  		var res, resok *ssa.Value
  1503  		if n.Rhs[0].Op() == ir.ODOTTYPE2 {
  1504  			res, resok = s.dottype(n.Rhs[0].(*ir.TypeAssertExpr), true)
  1505  		} else {
  1506  			res, resok = s.dynamicDottype(n.Rhs[0].(*ir.DynamicTypeAssertExpr), true)
  1507  		}
  1508  		deref := false
  1509  		if !ssa.CanSSA(n.Rhs[0].Type()) {
  1510  			if res.Op != ssa.OpLoad {
  1511  				s.Fatalf("dottype of non-load")
  1512  			}
  1513  			mem := s.mem()
  1514  			if res.Args[1] != mem {
  1515  				s.Fatalf("memory no longer live from 2-result dottype load")
  1516  			}
  1517  			deref = true
  1518  			res = res.Args[0]
  1519  		}
  1520  		s.assign(n.Lhs[0], res, deref, 0)
  1521  		s.assign(n.Lhs[1], resok, false, 0)
  1522  		return
  1523  
  1524  	case ir.OAS2FUNC:
  1525  		// We come here only when it is an intrinsic call returning two values.
  1526  		n := n.(*ir.AssignListStmt)
  1527  		call := n.Rhs[0].(*ir.CallExpr)
  1528  		if !ir.IsIntrinsicCall(call) {
  1529  			s.Fatalf("non-intrinsic AS2FUNC not expanded %v", call)
  1530  		}
  1531  		v := s.intrinsicCall(call)
  1532  		v1 := s.newValue1(ssa.OpSelect0, n.Lhs[0].Type(), v)
  1533  		v2 := s.newValue1(ssa.OpSelect1, n.Lhs[1].Type(), v)
  1534  		s.assign(n.Lhs[0], v1, false, 0)
  1535  		s.assign(n.Lhs[1], v2, false, 0)
  1536  		return
  1537  
  1538  	case ir.ODCL:
  1539  		n := n.(*ir.Decl)
  1540  		if v := n.X; v.Esc() == ir.EscHeap {
  1541  			s.newHeapaddr(v)
  1542  		}
  1543  
  1544  	case ir.OLABEL:
  1545  		n := n.(*ir.LabelStmt)
  1546  		sym := n.Label
  1547  		if sym.IsBlank() {
  1548  			// Nothing to do because the label isn't targetable. See issue 52278.
  1549  			break
  1550  		}
  1551  		lab := s.label(sym)
  1552  
  1553  		// The label might already have a target block via a goto.
  1554  		if lab.target == nil {
  1555  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1556  		}
  1557  
  1558  		// Go to that label.
  1559  		// (We pretend "label:" is preceded by "goto label", unless the predecessor is unreachable.)
  1560  		if s.curBlock != nil {
  1561  			b := s.endBlock()
  1562  			b.AddEdgeTo(lab.target)
  1563  		}
  1564  		s.startBlock(lab.target)
  1565  
  1566  	case ir.OGOTO:
  1567  		n := n.(*ir.BranchStmt)
  1568  		sym := n.Label
  1569  
  1570  		lab := s.label(sym)
  1571  		if lab.target == nil {
  1572  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1573  		}
  1574  
  1575  		b := s.endBlock()
  1576  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1577  		b.AddEdgeTo(lab.target)
  1578  
  1579  	case ir.OAS:
  1580  		n := n.(*ir.AssignStmt)
  1581  		if n.X == n.Y && n.X.Op() == ir.ONAME {
  1582  			// An x=x assignment. No point in doing anything
  1583  			// here. In addition, skipping this assignment
  1584  			// prevents generating:
  1585  			//   VARDEF x
  1586  			//   COPY x -> x
  1587  			// which is bad because x is incorrectly considered
  1588  			// dead before the vardef. See issue #14904.
  1589  			return
  1590  		}
  1591  
  1592  		// mayOverlap keeps track of whether the LHS and RHS might
  1593  		// refer to partially overlapping memory. Partial overlapping can
  1594  		// only happen for arrays, see the comment in moveWhichMayOverlap.
  1595  		//
  1596  		// If both sides of the assignment are not dereferences, then partial
  1597  		// overlap can't happen. Partial overlap can only occur only when the
  1598  		// arrays referenced are strictly smaller parts of the same base array.
  1599  		// If one side of the assignment is a full array, then partial overlap
  1600  		// can't happen. (The arrays are either disjoint or identical.)
  1601  		mayOverlap := n.X.Op() == ir.ODEREF && (n.Y != nil && n.Y.Op() == ir.ODEREF)
  1602  		if n.Y != nil && n.Y.Op() == ir.ODEREF {
  1603  			p := n.Y.(*ir.StarExpr).X
  1604  			for p.Op() == ir.OCONVNOP {
  1605  				p = p.(*ir.ConvExpr).X
  1606  			}
  1607  			if p.Op() == ir.OSPTR && p.(*ir.UnaryExpr).X.Type().IsString() {
  1608  				// Pointer fields of strings point to unmodifiable memory.
  1609  				// That memory can't overlap with the memory being written.
  1610  				mayOverlap = false
  1611  			}
  1612  		}
  1613  
  1614  		// Evaluate RHS.
  1615  		rhs := n.Y
  1616  		if rhs != nil {
  1617  			switch rhs.Op() {
  1618  			case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
  1619  				// All literals with nonzero fields have already been
  1620  				// rewritten during walk. Any that remain are just T{}
  1621  				// or equivalents. Use the zero value.
  1622  				if !ir.IsZero(rhs) {
  1623  					s.Fatalf("literal with nonzero value in SSA: %v", rhs)
  1624  				}
  1625  				rhs = nil
  1626  			case ir.OAPPEND:
  1627  				rhs := rhs.(*ir.CallExpr)
  1628  				// Check whether we're writing the result of an append back to the same slice.
  1629  				// If so, we handle it specially to avoid write barriers on the fast
  1630  				// (non-growth) path.
  1631  				if !ir.SameSafeExpr(n.X, rhs.Args[0]) || base.Flag.N != 0 {
  1632  					break
  1633  				}
  1634  				// If the slice can be SSA'd, it'll be on the stack,
  1635  				// so there will be no write barriers,
  1636  				// so there's no need to attempt to prevent them.
  1637  				if s.canSSA(n.X) {
  1638  					if base.Debug.Append > 0 { // replicating old diagnostic message
  1639  						base.WarnfAt(n.Pos(), "append: len-only update (in local slice)")
  1640  					}
  1641  					break
  1642  				}
  1643  				if base.Debug.Append > 0 {
  1644  					base.WarnfAt(n.Pos(), "append: len-only update")
  1645  				}
  1646  				s.append(rhs, true)
  1647  				return
  1648  			}
  1649  		}
  1650  
  1651  		if ir.IsBlank(n.X) {
  1652  			// _ = rhs
  1653  			// Just evaluate rhs for side-effects.
  1654  			if rhs != nil {
  1655  				s.expr(rhs)
  1656  			}
  1657  			return
  1658  		}
  1659  
  1660  		var t *types.Type
  1661  		if n.Y != nil {
  1662  			t = n.Y.Type()
  1663  		} else {
  1664  			t = n.X.Type()
  1665  		}
  1666  
  1667  		var r *ssa.Value
  1668  		deref := !ssa.CanSSA(t)
  1669  		if deref {
  1670  			if rhs == nil {
  1671  				r = nil // Signal assign to use OpZero.
  1672  			} else {
  1673  				r = s.addr(rhs)
  1674  			}
  1675  		} else {
  1676  			if rhs == nil {
  1677  				r = s.zeroVal(t)
  1678  			} else {
  1679  				r = s.expr(rhs)
  1680  			}
  1681  		}
  1682  
  1683  		var skip skipMask
  1684  		if rhs != nil && (rhs.Op() == ir.OSLICE || rhs.Op() == ir.OSLICE3 || rhs.Op() == ir.OSLICESTR) && ir.SameSafeExpr(rhs.(*ir.SliceExpr).X, n.X) {
  1685  			// We're assigning a slicing operation back to its source.
  1686  			// Don't write back fields we aren't changing. See issue #14855.
  1687  			rhs := rhs.(*ir.SliceExpr)
  1688  			i, j, k := rhs.Low, rhs.High, rhs.Max
  1689  			if i != nil && (i.Op() == ir.OLITERAL && i.Val().Kind() == constant.Int && ir.Int64Val(i) == 0) {
  1690  				// [0:...] is the same as [:...]
  1691  				i = nil
  1692  			}
  1693  			// TODO: detect defaults for len/cap also.
  1694  			// Currently doesn't really work because (*p)[:len(*p)] appears here as:
  1695  			//    tmp = len(*p)
  1696  			//    (*p)[:tmp]
  1697  			// if j != nil && (j.Op == OLEN && SameSafeExpr(j.Left, n.Left)) {
  1698  			//      j = nil
  1699  			// }
  1700  			// if k != nil && (k.Op == OCAP && SameSafeExpr(k.Left, n.Left)) {
  1701  			//      k = nil
  1702  			// }
  1703  			if i == nil {
  1704  				skip |= skipPtr
  1705  				if j == nil {
  1706  					skip |= skipLen
  1707  				}
  1708  				if k == nil {
  1709  					skip |= skipCap
  1710  				}
  1711  			}
  1712  		}
  1713  
  1714  		s.assignWhichMayOverlap(n.X, r, deref, skip, mayOverlap)
  1715  
  1716  	case ir.OIF:
  1717  		n := n.(*ir.IfStmt)
  1718  		if ir.IsConst(n.Cond, constant.Bool) {
  1719  			s.stmtList(n.Cond.Init())
  1720  			if ir.BoolVal(n.Cond) {
  1721  				s.stmtList(n.Body)
  1722  			} else {
  1723  				s.stmtList(n.Else)
  1724  			}
  1725  			break
  1726  		}
  1727  
  1728  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1729  		var likely int8
  1730  		if n.Likely {
  1731  			likely = 1
  1732  		}
  1733  		var bThen *ssa.Block
  1734  		if len(n.Body) != 0 {
  1735  			bThen = s.f.NewBlock(ssa.BlockPlain)
  1736  		} else {
  1737  			bThen = bEnd
  1738  		}
  1739  		var bElse *ssa.Block
  1740  		if len(n.Else) != 0 {
  1741  			bElse = s.f.NewBlock(ssa.BlockPlain)
  1742  		} else {
  1743  			bElse = bEnd
  1744  		}
  1745  		s.condBranch(n.Cond, bThen, bElse, likely)
  1746  
  1747  		if len(n.Body) != 0 {
  1748  			s.startBlock(bThen)
  1749  			s.stmtList(n.Body)
  1750  			if b := s.endBlock(); b != nil {
  1751  				b.AddEdgeTo(bEnd)
  1752  			}
  1753  		}
  1754  		if len(n.Else) != 0 {
  1755  			s.startBlock(bElse)
  1756  			s.stmtList(n.Else)
  1757  			if b := s.endBlock(); b != nil {
  1758  				b.AddEdgeTo(bEnd)
  1759  			}
  1760  		}
  1761  		s.startBlock(bEnd)
  1762  
  1763  	case ir.ORETURN:
  1764  		n := n.(*ir.ReturnStmt)
  1765  		s.stmtList(n.Results)
  1766  		b := s.exit()
  1767  		b.Pos = s.lastPos.WithIsStmt()
  1768  
  1769  	case ir.OTAILCALL:
  1770  		n := n.(*ir.TailCallStmt)
  1771  		s.callResult(n.Call, callTail)
  1772  		call := s.mem()
  1773  		b := s.endBlock()
  1774  		b.Kind = ssa.BlockRetJmp // could use BlockExit. BlockRetJmp is mostly for clarity.
  1775  		b.SetControl(call)
  1776  
  1777  	case ir.OCONTINUE, ir.OBREAK:
  1778  		n := n.(*ir.BranchStmt)
  1779  		var to *ssa.Block
  1780  		if n.Label == nil {
  1781  			// plain break/continue
  1782  			switch n.Op() {
  1783  			case ir.OCONTINUE:
  1784  				to = s.continueTo
  1785  			case ir.OBREAK:
  1786  				to = s.breakTo
  1787  			}
  1788  		} else {
  1789  			// labeled break/continue; look up the target
  1790  			sym := n.Label
  1791  			lab := s.label(sym)
  1792  			switch n.Op() {
  1793  			case ir.OCONTINUE:
  1794  				to = lab.continueTarget
  1795  			case ir.OBREAK:
  1796  				to = lab.breakTarget
  1797  			}
  1798  		}
  1799  
  1800  		b := s.endBlock()
  1801  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1802  		b.AddEdgeTo(to)
  1803  
  1804  	case ir.OFOR:
  1805  		// OFOR: for Ninit; Left; Right { Nbody }
  1806  		// cond (Left); body (Nbody); incr (Right)
  1807  		n := n.(*ir.ForStmt)
  1808  		base.Assert(!n.DistinctVars) // Should all be rewritten before escape analysis
  1809  		bCond := s.f.NewBlock(ssa.BlockPlain)
  1810  		bBody := s.f.NewBlock(ssa.BlockPlain)
  1811  		bIncr := s.f.NewBlock(ssa.BlockPlain)
  1812  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1813  
  1814  		// ensure empty for loops have correct position; issue #30167
  1815  		bBody.Pos = n.Pos()
  1816  
  1817  		// first, jump to condition test
  1818  		b := s.endBlock()
  1819  		b.AddEdgeTo(bCond)
  1820  
  1821  		// generate code to test condition
  1822  		s.startBlock(bCond)
  1823  		if n.Cond != nil {
  1824  			s.condBranch(n.Cond, bBody, bEnd, 1)
  1825  		} else {
  1826  			b := s.endBlock()
  1827  			b.Kind = ssa.BlockPlain
  1828  			b.AddEdgeTo(bBody)
  1829  		}
  1830  
  1831  		// set up for continue/break in body
  1832  		prevContinue := s.continueTo
  1833  		prevBreak := s.breakTo
  1834  		s.continueTo = bIncr
  1835  		s.breakTo = bEnd
  1836  		var lab *ssaLabel
  1837  		if sym := n.Label; sym != nil {
  1838  			// labeled for loop
  1839  			lab = s.label(sym)
  1840  			lab.continueTarget = bIncr
  1841  			lab.breakTarget = bEnd
  1842  		}
  1843  
  1844  		// generate body
  1845  		s.startBlock(bBody)
  1846  		s.stmtList(n.Body)
  1847  
  1848  		// tear down continue/break
  1849  		s.continueTo = prevContinue
  1850  		s.breakTo = prevBreak
  1851  		if lab != nil {
  1852  			lab.continueTarget = nil
  1853  			lab.breakTarget = nil
  1854  		}
  1855  
  1856  		// done with body, goto incr
  1857  		if b := s.endBlock(); b != nil {
  1858  			b.AddEdgeTo(bIncr)
  1859  		}
  1860  
  1861  		// generate incr
  1862  		s.startBlock(bIncr)
  1863  		if n.Post != nil {
  1864  			s.stmt(n.Post)
  1865  		}
  1866  		if b := s.endBlock(); b != nil {
  1867  			b.AddEdgeTo(bCond)
  1868  			// It can happen that bIncr ends in a block containing only VARKILL,
  1869  			// and that muddles the debugging experience.
  1870  			if b.Pos == src.NoXPos {
  1871  				b.Pos = bCond.Pos
  1872  			}
  1873  		}
  1874  
  1875  		s.startBlock(bEnd)
  1876  
  1877  	case ir.OSWITCH, ir.OSELECT:
  1878  		// These have been mostly rewritten by the front end into their Nbody fields.
  1879  		// Our main task is to correctly hook up any break statements.
  1880  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1881  
  1882  		prevBreak := s.breakTo
  1883  		s.breakTo = bEnd
  1884  		var sym *types.Sym
  1885  		var body ir.Nodes
  1886  		if n.Op() == ir.OSWITCH {
  1887  			n := n.(*ir.SwitchStmt)
  1888  			sym = n.Label
  1889  			body = n.Compiled
  1890  		} else {
  1891  			n := n.(*ir.SelectStmt)
  1892  			sym = n.Label
  1893  			body = n.Compiled
  1894  		}
  1895  
  1896  		var lab *ssaLabel
  1897  		if sym != nil {
  1898  			// labeled
  1899  			lab = s.label(sym)
  1900  			lab.breakTarget = bEnd
  1901  		}
  1902  
  1903  		// generate body code
  1904  		s.stmtList(body)
  1905  
  1906  		s.breakTo = prevBreak
  1907  		if lab != nil {
  1908  			lab.breakTarget = nil
  1909  		}
  1910  
  1911  		// walk adds explicit OBREAK nodes to the end of all reachable code paths.
  1912  		// If we still have a current block here, then mark it unreachable.
  1913  		if s.curBlock != nil {
  1914  			m := s.mem()
  1915  			b := s.endBlock()
  1916  			b.Kind = ssa.BlockExit
  1917  			b.SetControl(m)
  1918  		}
  1919  		s.startBlock(bEnd)
  1920  
  1921  	case ir.OJUMPTABLE:
  1922  		n := n.(*ir.JumpTableStmt)
  1923  
  1924  		// Make blocks we'll need.
  1925  		jt := s.f.NewBlock(ssa.BlockJumpTable)
  1926  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1927  
  1928  		// The only thing that needs evaluating is the index we're looking up.
  1929  		idx := s.expr(n.Idx)
  1930  		unsigned := idx.Type.IsUnsigned()
  1931  
  1932  		// Extend so we can do everything in uintptr arithmetic.
  1933  		t := types.Types[types.TUINTPTR]
  1934  		idx = s.conv(nil, idx, idx.Type, t)
  1935  
  1936  		// The ending condition for the current block decides whether we'll use
  1937  		// the jump table at all.
  1938  		// We check that min <= idx <= max and jump around the jump table
  1939  		// if that test fails.
  1940  		// We implement min <= idx <= max with 0 <= idx-min <= max-min, because
  1941  		// we'll need idx-min anyway as the control value for the jump table.
  1942  		var min, max uint64
  1943  		if unsigned {
  1944  			min, _ = constant.Uint64Val(n.Cases[0])
  1945  			max, _ = constant.Uint64Val(n.Cases[len(n.Cases)-1])
  1946  		} else {
  1947  			mn, _ := constant.Int64Val(n.Cases[0])
  1948  			mx, _ := constant.Int64Val(n.Cases[len(n.Cases)-1])
  1949  			min = uint64(mn)
  1950  			max = uint64(mx)
  1951  		}
  1952  		// Compare idx-min with max-min, to see if we can use the jump table.
  1953  		idx = s.newValue2(s.ssaOp(ir.OSUB, t), t, idx, s.uintptrConstant(min))
  1954  		width := s.uintptrConstant(max - min)
  1955  		cmp := s.newValue2(s.ssaOp(ir.OLE, t), types.Types[types.TBOOL], idx, width)
  1956  		b := s.endBlock()
  1957  		b.Kind = ssa.BlockIf
  1958  		b.SetControl(cmp)
  1959  		b.AddEdgeTo(jt)             // in range - use jump table
  1960  		b.AddEdgeTo(bEnd)           // out of range - no case in the jump table will trigger
  1961  		b.Likely = ssa.BranchLikely // TODO: assumes missing the table entirely is unlikely. True?
  1962  
  1963  		// Build jump table block.
  1964  		s.startBlock(jt)
  1965  		jt.Pos = n.Pos()
  1966  		if base.Flag.Cfg.SpectreIndex {
  1967  			idx = s.newValue2(ssa.OpSpectreSliceIndex, t, idx, width)
  1968  		}
  1969  		jt.SetControl(idx)
  1970  
  1971  		// Figure out where we should go for each index in the table.
  1972  		table := make([]*ssa.Block, max-min+1)
  1973  		for i := range table {
  1974  			table[i] = bEnd // default target
  1975  		}
  1976  		for i := range n.Targets {
  1977  			c := n.Cases[i]
  1978  			lab := s.label(n.Targets[i])
  1979  			if lab.target == nil {
  1980  				lab.target = s.f.NewBlock(ssa.BlockPlain)
  1981  			}
  1982  			var val uint64
  1983  			if unsigned {
  1984  				val, _ = constant.Uint64Val(c)
  1985  			} else {
  1986  				vl, _ := constant.Int64Val(c)
  1987  				val = uint64(vl)
  1988  			}
  1989  			// Overwrite the default target.
  1990  			table[val-min] = lab.target
  1991  		}
  1992  		for _, t := range table {
  1993  			jt.AddEdgeTo(t)
  1994  		}
  1995  		s.endBlock()
  1996  
  1997  		s.startBlock(bEnd)
  1998  
  1999  	case ir.OINTERFACESWITCH:
  2000  		n := n.(*ir.InterfaceSwitchStmt)
  2001  		typs := s.f.Config.Types
  2002  
  2003  		t := s.expr(n.RuntimeType)
  2004  		h := s.expr(n.Hash)
  2005  		d := s.newValue1A(ssa.OpAddr, typs.BytePtr, n.Descriptor, s.sb)
  2006  
  2007  		// Check the cache first.
  2008  		var merge *ssa.Block
  2009  		if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Name) {
  2010  			// Note: we can only use the cache if we have the right atomic load instruction.
  2011  			// Double-check that here.
  2012  			if _, ok := intrinsics[intrinsicKey{Arch.LinkArch.Arch, "runtime/internal/atomic", "Loadp"}]; !ok {
  2013  				s.Fatalf("atomic load not available")
  2014  			}
  2015  			merge = s.f.NewBlock(ssa.BlockPlain)
  2016  			cacheHit := s.f.NewBlock(ssa.BlockPlain)
  2017  			cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  2018  			loopHead := s.f.NewBlock(ssa.BlockPlain)
  2019  			loopBody := s.f.NewBlock(ssa.BlockPlain)
  2020  
  2021  			// Pick right size ops.
  2022  			var mul, and, add, zext ssa.Op
  2023  			if s.config.PtrSize == 4 {
  2024  				mul = ssa.OpMul32
  2025  				and = ssa.OpAnd32
  2026  				add = ssa.OpAdd32
  2027  				zext = ssa.OpCopy
  2028  			} else {
  2029  				mul = ssa.OpMul64
  2030  				and = ssa.OpAnd64
  2031  				add = ssa.OpAdd64
  2032  				zext = ssa.OpZeroExt32to64
  2033  			}
  2034  
  2035  			// Load cache pointer out of descriptor, with an atomic load so
  2036  			// we ensure that we see a fully written cache.
  2037  			atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  2038  			cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  2039  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  2040  
  2041  			// Initialize hash variable.
  2042  			s.vars[hashVar] = s.newValue1(zext, typs.Uintptr, h)
  2043  
  2044  			// Load mask from cache.
  2045  			mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  2046  			// Jump to loop head.
  2047  			b := s.endBlock()
  2048  			b.AddEdgeTo(loopHead)
  2049  
  2050  			// At loop head, get pointer to the cache entry.
  2051  			//   e := &cache.Entries[hash&mask]
  2052  			s.startBlock(loopHead)
  2053  			entries := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, s.uintptrConstant(uint64(s.config.PtrSize)))
  2054  			idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  2055  			idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(3*s.config.PtrSize)))
  2056  			e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, entries, idx)
  2057  			//   hash++
  2058  			s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  2059  
  2060  			// Look for a cache hit.
  2061  			//   if e.Typ == t { goto hit }
  2062  			eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  2063  			cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, t, eTyp)
  2064  			b = s.endBlock()
  2065  			b.Kind = ssa.BlockIf
  2066  			b.SetControl(cmp1)
  2067  			b.AddEdgeTo(cacheHit)
  2068  			b.AddEdgeTo(loopBody)
  2069  
  2070  			// Look for an empty entry, the tombstone for this hash table.
  2071  			//   if e.Typ == nil { goto miss }
  2072  			s.startBlock(loopBody)
  2073  			cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  2074  			b = s.endBlock()
  2075  			b.Kind = ssa.BlockIf
  2076  			b.SetControl(cmp2)
  2077  			b.AddEdgeTo(cacheMiss)
  2078  			b.AddEdgeTo(loopHead)
  2079  
  2080  			// On a hit, load the data fields of the cache entry.
  2081  			//   Case = e.Case
  2082  			//   Itab = e.Itab
  2083  			s.startBlock(cacheHit)
  2084  			eCase := s.newValue2(ssa.OpLoad, typs.Int, s.newValue1I(ssa.OpOffPtr, typs.IntPtr, s.config.PtrSize, e), s.mem())
  2085  			eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, 2*s.config.PtrSize, e), s.mem())
  2086  			s.assign(n.Case, eCase, false, 0)
  2087  			s.assign(n.Itab, eItab, false, 0)
  2088  			b = s.endBlock()
  2089  			b.AddEdgeTo(merge)
  2090  
  2091  			// On a miss, call into the runtime to get the answer.
  2092  			s.startBlock(cacheMiss)
  2093  		}
  2094  
  2095  		r := s.rtcall(ir.Syms.InterfaceSwitch, true, []*types.Type{typs.Int, typs.BytePtr}, d, t)
  2096  		s.assign(n.Case, r[0], false, 0)
  2097  		s.assign(n.Itab, r[1], false, 0)
  2098  
  2099  		if merge != nil {
  2100  			// Cache hits merge in here.
  2101  			b := s.endBlock()
  2102  			b.Kind = ssa.BlockPlain
  2103  			b.AddEdgeTo(merge)
  2104  			s.startBlock(merge)
  2105  		}
  2106  
  2107  	case ir.OCHECKNIL:
  2108  		n := n.(*ir.UnaryExpr)
  2109  		p := s.expr(n.X)
  2110  		_ = s.nilCheck(p)
  2111  		// TODO: check that throwing away the nilcheck result is ok.
  2112  
  2113  	case ir.OINLMARK:
  2114  		n := n.(*ir.InlineMarkStmt)
  2115  		s.newValue1I(ssa.OpInlMark, types.TypeVoid, n.Index, s.mem())
  2116  
  2117  	default:
  2118  		s.Fatalf("unhandled stmt %v", n.Op())
  2119  	}
  2120  }
  2121  
  2122  // If true, share as many open-coded defer exits as possible (with the downside of
  2123  // worse line-number information)
  2124  const shareDeferExits = false
  2125  
  2126  // exit processes any code that needs to be generated just before returning.
  2127  // It returns a BlockRet block that ends the control flow. Its control value
  2128  // will be set to the final memory state.
  2129  func (s *state) exit() *ssa.Block {
  2130  	if s.hasdefer {
  2131  		if s.hasOpenDefers {
  2132  			if shareDeferExits && s.lastDeferExit != nil && len(s.openDefers) == s.lastDeferCount {
  2133  				if s.curBlock.Kind != ssa.BlockPlain {
  2134  					panic("Block for an exit should be BlockPlain")
  2135  				}
  2136  				s.curBlock.AddEdgeTo(s.lastDeferExit)
  2137  				s.endBlock()
  2138  				return s.lastDeferFinalBlock
  2139  			}
  2140  			s.openDeferExit()
  2141  		} else {
  2142  			s.rtcall(ir.Syms.Deferreturn, true, nil)
  2143  		}
  2144  	}
  2145  
  2146  	// Do actual return.
  2147  	// These currently turn into self-copies (in many cases).
  2148  	resultFields := s.curfn.Type().Results()
  2149  	results := make([]*ssa.Value, len(resultFields)+1, len(resultFields)+1)
  2150  	// Store SSAable and heap-escaped PPARAMOUT variables back to stack locations.
  2151  	for i, f := range resultFields {
  2152  		n := f.Nname.(*ir.Name)
  2153  		if s.canSSA(n) { // result is in some SSA variable
  2154  			if !n.IsOutputParamInRegisters() && n.Type().HasPointers() {
  2155  				// We are about to store to the result slot.
  2156  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2157  			}
  2158  			results[i] = s.variable(n, n.Type())
  2159  		} else if !n.OnStack() { // result is actually heap allocated
  2160  			// We are about to copy the in-heap result to the result slot.
  2161  			if n.Type().HasPointers() {
  2162  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2163  			}
  2164  			ha := s.expr(n.Heapaddr)
  2165  			s.instrumentFields(n.Type(), ha, instrumentRead)
  2166  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), ha, s.mem())
  2167  		} else { // result is not SSA-able; not escaped, so not on heap, but too large for SSA.
  2168  			// Before register ABI this ought to be a self-move, home=dest,
  2169  			// With register ABI, it's still a self-move if parameter is on stack (i.e., too big or overflowed)
  2170  			// No VarDef, as the result slot is already holding live value.
  2171  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), s.addr(n), s.mem())
  2172  		}
  2173  	}
  2174  
  2175  	// In -race mode, we need to call racefuncexit.
  2176  	// Note: This has to happen after we load any heap-allocated results,
  2177  	// otherwise races will be attributed to the caller instead.
  2178  	if s.instrumentEnterExit {
  2179  		s.rtcall(ir.Syms.Racefuncexit, true, nil)
  2180  	}
  2181  
  2182  	results[len(results)-1] = s.mem()
  2183  	m := s.newValue0(ssa.OpMakeResult, s.f.OwnAux.LateExpansionResultType())
  2184  	m.AddArgs(results...)
  2185  
  2186  	b := s.endBlock()
  2187  	b.Kind = ssa.BlockRet
  2188  	b.SetControl(m)
  2189  	if s.hasdefer && s.hasOpenDefers {
  2190  		s.lastDeferFinalBlock = b
  2191  	}
  2192  	return b
  2193  }
  2194  
  2195  type opAndType struct {
  2196  	op    ir.Op
  2197  	etype types.Kind
  2198  }
  2199  
  2200  var opToSSA = map[opAndType]ssa.Op{
  2201  	{ir.OADD, types.TINT8}:    ssa.OpAdd8,
  2202  	{ir.OADD, types.TUINT8}:   ssa.OpAdd8,
  2203  	{ir.OADD, types.TINT16}:   ssa.OpAdd16,
  2204  	{ir.OADD, types.TUINT16}:  ssa.OpAdd16,
  2205  	{ir.OADD, types.TINT32}:   ssa.OpAdd32,
  2206  	{ir.OADD, types.TUINT32}:  ssa.OpAdd32,
  2207  	{ir.OADD, types.TINT64}:   ssa.OpAdd64,
  2208  	{ir.OADD, types.TUINT64}:  ssa.OpAdd64,
  2209  	{ir.OADD, types.TFLOAT32}: ssa.OpAdd32F,
  2210  	{ir.OADD, types.TFLOAT64}: ssa.OpAdd64F,
  2211  
  2212  	{ir.OSUB, types.TINT8}:    ssa.OpSub8,
  2213  	{ir.OSUB, types.TUINT8}:   ssa.OpSub8,
  2214  	{ir.OSUB, types.TINT16}:   ssa.OpSub16,
  2215  	{ir.OSUB, types.TUINT16}:  ssa.OpSub16,
  2216  	{ir.OSUB, types.TINT32}:   ssa.OpSub32,
  2217  	{ir.OSUB, types.TUINT32}:  ssa.OpSub32,
  2218  	{ir.OSUB, types.TINT64}:   ssa.OpSub64,
  2219  	{ir.OSUB, types.TUINT64}:  ssa.OpSub64,
  2220  	{ir.OSUB, types.TFLOAT32}: ssa.OpSub32F,
  2221  	{ir.OSUB, types.TFLOAT64}: ssa.OpSub64F,
  2222  
  2223  	{ir.ONOT, types.TBOOL}: ssa.OpNot,
  2224  
  2225  	{ir.ONEG, types.TINT8}:    ssa.OpNeg8,
  2226  	{ir.ONEG, types.TUINT8}:   ssa.OpNeg8,
  2227  	{ir.ONEG, types.TINT16}:   ssa.OpNeg16,
  2228  	{ir.ONEG, types.TUINT16}:  ssa.OpNeg16,
  2229  	{ir.ONEG, types.TINT32}:   ssa.OpNeg32,
  2230  	{ir.ONEG, types.TUINT32}:  ssa.OpNeg32,
  2231  	{ir.ONEG, types.TINT64}:   ssa.OpNeg64,
  2232  	{ir.ONEG, types.TUINT64}:  ssa.OpNeg64,
  2233  	{ir.ONEG, types.TFLOAT32}: ssa.OpNeg32F,
  2234  	{ir.ONEG, types.TFLOAT64}: ssa.OpNeg64F,
  2235  
  2236  	{ir.OBITNOT, types.TINT8}:   ssa.OpCom8,
  2237  	{ir.OBITNOT, types.TUINT8}:  ssa.OpCom8,
  2238  	{ir.OBITNOT, types.TINT16}:  ssa.OpCom16,
  2239  	{ir.OBITNOT, types.TUINT16}: ssa.OpCom16,
  2240  	{ir.OBITNOT, types.TINT32}:  ssa.OpCom32,
  2241  	{ir.OBITNOT, types.TUINT32}: ssa.OpCom32,
  2242  	{ir.OBITNOT, types.TINT64}:  ssa.OpCom64,
  2243  	{ir.OBITNOT, types.TUINT64}: ssa.OpCom64,
  2244  
  2245  	{ir.OIMAG, types.TCOMPLEX64}:  ssa.OpComplexImag,
  2246  	{ir.OIMAG, types.TCOMPLEX128}: ssa.OpComplexImag,
  2247  	{ir.OREAL, types.TCOMPLEX64}:  ssa.OpComplexReal,
  2248  	{ir.OREAL, types.TCOMPLEX128}: ssa.OpComplexReal,
  2249  
  2250  	{ir.OMUL, types.TINT8}:    ssa.OpMul8,
  2251  	{ir.OMUL, types.TUINT8}:   ssa.OpMul8,
  2252  	{ir.OMUL, types.TINT16}:   ssa.OpMul16,
  2253  	{ir.OMUL, types.TUINT16}:  ssa.OpMul16,
  2254  	{ir.OMUL, types.TINT32}:   ssa.OpMul32,
  2255  	{ir.OMUL, types.TUINT32}:  ssa.OpMul32,
  2256  	{ir.OMUL, types.TINT64}:   ssa.OpMul64,
  2257  	{ir.OMUL, types.TUINT64}:  ssa.OpMul64,
  2258  	{ir.OMUL, types.TFLOAT32}: ssa.OpMul32F,
  2259  	{ir.OMUL, types.TFLOAT64}: ssa.OpMul64F,
  2260  
  2261  	{ir.ODIV, types.TFLOAT32}: ssa.OpDiv32F,
  2262  	{ir.ODIV, types.TFLOAT64}: ssa.OpDiv64F,
  2263  
  2264  	{ir.ODIV, types.TINT8}:   ssa.OpDiv8,
  2265  	{ir.ODIV, types.TUINT8}:  ssa.OpDiv8u,
  2266  	{ir.ODIV, types.TINT16}:  ssa.OpDiv16,
  2267  	{ir.ODIV, types.TUINT16}: ssa.OpDiv16u,
  2268  	{ir.ODIV, types.TINT32}:  ssa.OpDiv32,
  2269  	{ir.ODIV, types.TUINT32}: ssa.OpDiv32u,
  2270  	{ir.ODIV, types.TINT64}:  ssa.OpDiv64,
  2271  	{ir.ODIV, types.TUINT64}: ssa.OpDiv64u,
  2272  
  2273  	{ir.OMOD, types.TINT8}:   ssa.OpMod8,
  2274  	{ir.OMOD, types.TUINT8}:  ssa.OpMod8u,
  2275  	{ir.OMOD, types.TINT16}:  ssa.OpMod16,
  2276  	{ir.OMOD, types.TUINT16}: ssa.OpMod16u,
  2277  	{ir.OMOD, types.TINT32}:  ssa.OpMod32,
  2278  	{ir.OMOD, types.TUINT32}: ssa.OpMod32u,
  2279  	{ir.OMOD, types.TINT64}:  ssa.OpMod64,
  2280  	{ir.OMOD, types.TUINT64}: ssa.OpMod64u,
  2281  
  2282  	{ir.OAND, types.TINT8}:   ssa.OpAnd8,
  2283  	{ir.OAND, types.TUINT8}:  ssa.OpAnd8,
  2284  	{ir.OAND, types.TINT16}:  ssa.OpAnd16,
  2285  	{ir.OAND, types.TUINT16}: ssa.OpAnd16,
  2286  	{ir.OAND, types.TINT32}:  ssa.OpAnd32,
  2287  	{ir.OAND, types.TUINT32}: ssa.OpAnd32,
  2288  	{ir.OAND, types.TINT64}:  ssa.OpAnd64,
  2289  	{ir.OAND, types.TUINT64}: ssa.OpAnd64,
  2290  
  2291  	{ir.OOR, types.TINT8}:   ssa.OpOr8,
  2292  	{ir.OOR, types.TUINT8}:  ssa.OpOr8,
  2293  	{ir.OOR, types.TINT16}:  ssa.OpOr16,
  2294  	{ir.OOR, types.TUINT16}: ssa.OpOr16,
  2295  	{ir.OOR, types.TINT32}:  ssa.OpOr32,
  2296  	{ir.OOR, types.TUINT32}: ssa.OpOr32,
  2297  	{ir.OOR, types.TINT64}:  ssa.OpOr64,
  2298  	{ir.OOR, types.TUINT64}: ssa.OpOr64,
  2299  
  2300  	{ir.OXOR, types.TINT8}:   ssa.OpXor8,
  2301  	{ir.OXOR, types.TUINT8}:  ssa.OpXor8,
  2302  	{ir.OXOR, types.TINT16}:  ssa.OpXor16,
  2303  	{ir.OXOR, types.TUINT16}: ssa.OpXor16,
  2304  	{ir.OXOR, types.TINT32}:  ssa.OpXor32,
  2305  	{ir.OXOR, types.TUINT32}: ssa.OpXor32,
  2306  	{ir.OXOR, types.TINT64}:  ssa.OpXor64,
  2307  	{ir.OXOR, types.TUINT64}: ssa.OpXor64,
  2308  
  2309  	{ir.OEQ, types.TBOOL}:      ssa.OpEqB,
  2310  	{ir.OEQ, types.TINT8}:      ssa.OpEq8,
  2311  	{ir.OEQ, types.TUINT8}:     ssa.OpEq8,
  2312  	{ir.OEQ, types.TINT16}:     ssa.OpEq16,
  2313  	{ir.OEQ, types.TUINT16}:    ssa.OpEq16,
  2314  	{ir.OEQ, types.TINT32}:     ssa.OpEq32,
  2315  	{ir.OEQ, types.TUINT32}:    ssa.OpEq32,
  2316  	{ir.OEQ, types.TINT64}:     ssa.OpEq64,
  2317  	{ir.OEQ, types.TUINT64}:    ssa.OpEq64,
  2318  	{ir.OEQ, types.TINTER}:     ssa.OpEqInter,
  2319  	{ir.OEQ, types.TSLICE}:     ssa.OpEqSlice,
  2320  	{ir.OEQ, types.TFUNC}:      ssa.OpEqPtr,
  2321  	{ir.OEQ, types.TMAP}:       ssa.OpEqPtr,
  2322  	{ir.OEQ, types.TCHAN}:      ssa.OpEqPtr,
  2323  	{ir.OEQ, types.TPTR}:       ssa.OpEqPtr,
  2324  	{ir.OEQ, types.TUINTPTR}:   ssa.OpEqPtr,
  2325  	{ir.OEQ, types.TUNSAFEPTR}: ssa.OpEqPtr,
  2326  	{ir.OEQ, types.TFLOAT64}:   ssa.OpEq64F,
  2327  	{ir.OEQ, types.TFLOAT32}:   ssa.OpEq32F,
  2328  
  2329  	{ir.ONE, types.TBOOL}:      ssa.OpNeqB,
  2330  	{ir.ONE, types.TINT8}:      ssa.OpNeq8,
  2331  	{ir.ONE, types.TUINT8}:     ssa.OpNeq8,
  2332  	{ir.ONE, types.TINT16}:     ssa.OpNeq16,
  2333  	{ir.ONE, types.TUINT16}:    ssa.OpNeq16,
  2334  	{ir.ONE, types.TINT32}:     ssa.OpNeq32,
  2335  	{ir.ONE, types.TUINT32}:    ssa.OpNeq32,
  2336  	{ir.ONE, types.TINT64}:     ssa.OpNeq64,
  2337  	{ir.ONE, types.TUINT64}:    ssa.OpNeq64,
  2338  	{ir.ONE, types.TINTER}:     ssa.OpNeqInter,
  2339  	{ir.ONE, types.TSLICE}:     ssa.OpNeqSlice,
  2340  	{ir.ONE, types.TFUNC}:      ssa.OpNeqPtr,
  2341  	{ir.ONE, types.TMAP}:       ssa.OpNeqPtr,
  2342  	{ir.ONE, types.TCHAN}:      ssa.OpNeqPtr,
  2343  	{ir.ONE, types.TPTR}:       ssa.OpNeqPtr,
  2344  	{ir.ONE, types.TUINTPTR}:   ssa.OpNeqPtr,
  2345  	{ir.ONE, types.TUNSAFEPTR}: ssa.OpNeqPtr,
  2346  	{ir.ONE, types.TFLOAT64}:   ssa.OpNeq64F,
  2347  	{ir.ONE, types.TFLOAT32}:   ssa.OpNeq32F,
  2348  
  2349  	{ir.OLT, types.TINT8}:    ssa.OpLess8,
  2350  	{ir.OLT, types.TUINT8}:   ssa.OpLess8U,
  2351  	{ir.OLT, types.TINT16}:   ssa.OpLess16,
  2352  	{ir.OLT, types.TUINT16}:  ssa.OpLess16U,
  2353  	{ir.OLT, types.TINT32}:   ssa.OpLess32,
  2354  	{ir.OLT, types.TUINT32}:  ssa.OpLess32U,
  2355  	{ir.OLT, types.TINT64}:   ssa.OpLess64,
  2356  	{ir.OLT, types.TUINT64}:  ssa.OpLess64U,
  2357  	{ir.OLT, types.TFLOAT64}: ssa.OpLess64F,
  2358  	{ir.OLT, types.TFLOAT32}: ssa.OpLess32F,
  2359  
  2360  	{ir.OLE, types.TINT8}:    ssa.OpLeq8,
  2361  	{ir.OLE, types.TUINT8}:   ssa.OpLeq8U,
  2362  	{ir.OLE, types.TINT16}:   ssa.OpLeq16,
  2363  	{ir.OLE, types.TUINT16}:  ssa.OpLeq16U,
  2364  	{ir.OLE, types.TINT32}:   ssa.OpLeq32,
  2365  	{ir.OLE, types.TUINT32}:  ssa.OpLeq32U,
  2366  	{ir.OLE, types.TINT64}:   ssa.OpLeq64,
  2367  	{ir.OLE, types.TUINT64}:  ssa.OpLeq64U,
  2368  	{ir.OLE, types.TFLOAT64}: ssa.OpLeq64F,
  2369  	{ir.OLE, types.TFLOAT32}: ssa.OpLeq32F,
  2370  }
  2371  
  2372  func (s *state) concreteEtype(t *types.Type) types.Kind {
  2373  	e := t.Kind()
  2374  	switch e {
  2375  	default:
  2376  		return e
  2377  	case types.TINT:
  2378  		if s.config.PtrSize == 8 {
  2379  			return types.TINT64
  2380  		}
  2381  		return types.TINT32
  2382  	case types.TUINT:
  2383  		if s.config.PtrSize == 8 {
  2384  			return types.TUINT64
  2385  		}
  2386  		return types.TUINT32
  2387  	case types.TUINTPTR:
  2388  		if s.config.PtrSize == 8 {
  2389  			return types.TUINT64
  2390  		}
  2391  		return types.TUINT32
  2392  	}
  2393  }
  2394  
  2395  func (s *state) ssaOp(op ir.Op, t *types.Type) ssa.Op {
  2396  	etype := s.concreteEtype(t)
  2397  	x, ok := opToSSA[opAndType{op, etype}]
  2398  	if !ok {
  2399  		s.Fatalf("unhandled binary op %v %s", op, etype)
  2400  	}
  2401  	return x
  2402  }
  2403  
  2404  type opAndTwoTypes struct {
  2405  	op     ir.Op
  2406  	etype1 types.Kind
  2407  	etype2 types.Kind
  2408  }
  2409  
  2410  type twoTypes struct {
  2411  	etype1 types.Kind
  2412  	etype2 types.Kind
  2413  }
  2414  
  2415  type twoOpsAndType struct {
  2416  	op1              ssa.Op
  2417  	op2              ssa.Op
  2418  	intermediateType types.Kind
  2419  }
  2420  
  2421  var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2422  
  2423  	{types.TINT8, types.TFLOAT32}:  {ssa.OpSignExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2424  	{types.TINT16, types.TFLOAT32}: {ssa.OpSignExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2425  	{types.TINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32to32F, types.TINT32},
  2426  	{types.TINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64to32F, types.TINT64},
  2427  
  2428  	{types.TINT8, types.TFLOAT64}:  {ssa.OpSignExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2429  	{types.TINT16, types.TFLOAT64}: {ssa.OpSignExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2430  	{types.TINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32to64F, types.TINT32},
  2431  	{types.TINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64to64F, types.TINT64},
  2432  
  2433  	{types.TFLOAT32, types.TINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2434  	{types.TFLOAT32, types.TINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2435  	{types.TFLOAT32, types.TINT32}: {ssa.OpCvt32Fto32, ssa.OpCopy, types.TINT32},
  2436  	{types.TFLOAT32, types.TINT64}: {ssa.OpCvt32Fto64, ssa.OpCopy, types.TINT64},
  2437  
  2438  	{types.TFLOAT64, types.TINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2439  	{types.TFLOAT64, types.TINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2440  	{types.TFLOAT64, types.TINT32}: {ssa.OpCvt64Fto32, ssa.OpCopy, types.TINT32},
  2441  	{types.TFLOAT64, types.TINT64}: {ssa.OpCvt64Fto64, ssa.OpCopy, types.TINT64},
  2442  	// unsigned
  2443  	{types.TUINT8, types.TFLOAT32}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2444  	{types.TUINT16, types.TFLOAT32}: {ssa.OpZeroExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2445  	{types.TUINT32, types.TFLOAT32}: {ssa.OpZeroExt32to64, ssa.OpCvt64to32F, types.TINT64}, // go wide to dodge unsigned
  2446  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto32F, branchy code expansion instead
  2447  
  2448  	{types.TUINT8, types.TFLOAT64}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2449  	{types.TUINT16, types.TFLOAT64}: {ssa.OpZeroExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2450  	{types.TUINT32, types.TFLOAT64}: {ssa.OpZeroExt32to64, ssa.OpCvt64to64F, types.TINT64}, // go wide to dodge unsigned
  2451  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto64F, branchy code expansion instead
  2452  
  2453  	{types.TFLOAT32, types.TUINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2454  	{types.TFLOAT32, types.TUINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2455  	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
  2456  	{types.TFLOAT32, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt32Fto64U, branchy code expansion instead
  2457  
  2458  	{types.TFLOAT64, types.TUINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2459  	{types.TFLOAT64, types.TUINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2460  	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
  2461  	{types.TFLOAT64, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt64Fto64U, branchy code expansion instead
  2462  
  2463  	// float
  2464  	{types.TFLOAT64, types.TFLOAT32}: {ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
  2465  	{types.TFLOAT64, types.TFLOAT64}: {ssa.OpRound64F, ssa.OpCopy, types.TFLOAT64},
  2466  	{types.TFLOAT32, types.TFLOAT32}: {ssa.OpRound32F, ssa.OpCopy, types.TFLOAT32},
  2467  	{types.TFLOAT32, types.TFLOAT64}: {ssa.OpCvt32Fto64F, ssa.OpCopy, types.TFLOAT64},
  2468  }
  2469  
  2470  // this map is used only for 32-bit arch, and only includes the difference
  2471  // on 32-bit arch, don't use int64<->float conversion for uint32
  2472  var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
  2473  	{types.TUINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32Uto32F, types.TUINT32},
  2474  	{types.TUINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32Uto64F, types.TUINT32},
  2475  	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto32U, ssa.OpCopy, types.TUINT32},
  2476  	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto32U, ssa.OpCopy, types.TUINT32},
  2477  }
  2478  
  2479  // uint64<->float conversions, only on machines that have instructions for that
  2480  var uint64fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2481  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64Uto32F, types.TUINT64},
  2482  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64Uto64F, types.TUINT64},
  2483  	{types.TFLOAT32, types.TUINT64}: {ssa.OpCvt32Fto64U, ssa.OpCopy, types.TUINT64},
  2484  	{types.TFLOAT64, types.TUINT64}: {ssa.OpCvt64Fto64U, ssa.OpCopy, types.TUINT64},
  2485  }
  2486  
  2487  var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
  2488  	{ir.OLSH, types.TINT8, types.TUINT8}:   ssa.OpLsh8x8,
  2489  	{ir.OLSH, types.TUINT8, types.TUINT8}:  ssa.OpLsh8x8,
  2490  	{ir.OLSH, types.TINT8, types.TUINT16}:  ssa.OpLsh8x16,
  2491  	{ir.OLSH, types.TUINT8, types.TUINT16}: ssa.OpLsh8x16,
  2492  	{ir.OLSH, types.TINT8, types.TUINT32}:  ssa.OpLsh8x32,
  2493  	{ir.OLSH, types.TUINT8, types.TUINT32}: ssa.OpLsh8x32,
  2494  	{ir.OLSH, types.TINT8, types.TUINT64}:  ssa.OpLsh8x64,
  2495  	{ir.OLSH, types.TUINT8, types.TUINT64}: ssa.OpLsh8x64,
  2496  
  2497  	{ir.OLSH, types.TINT16, types.TUINT8}:   ssa.OpLsh16x8,
  2498  	{ir.OLSH, types.TUINT16, types.TUINT8}:  ssa.OpLsh16x8,
  2499  	{ir.OLSH, types.TINT16, types.TUINT16}:  ssa.OpLsh16x16,
  2500  	{ir.OLSH, types.TUINT16, types.TUINT16}: ssa.OpLsh16x16,
  2501  	{ir.OLSH, types.TINT16, types.TUINT32}:  ssa.OpLsh16x32,
  2502  	{ir.OLSH, types.TUINT16, types.TUINT32}: ssa.OpLsh16x32,
  2503  	{ir.OLSH, types.TINT16, types.TUINT64}:  ssa.OpLsh16x64,
  2504  	{ir.OLSH, types.TUINT16, types.TUINT64}: ssa.OpLsh16x64,
  2505  
  2506  	{ir.OLSH, types.TINT32, types.TUINT8}:   ssa.OpLsh32x8,
  2507  	{ir.OLSH, types.TUINT32, types.TUINT8}:  ssa.OpLsh32x8,
  2508  	{ir.OLSH, types.TINT32, types.TUINT16}:  ssa.OpLsh32x16,
  2509  	{ir.OLSH, types.TUINT32, types.TUINT16}: ssa.OpLsh32x16,
  2510  	{ir.OLSH, types.TINT32, types.TUINT32}:  ssa.OpLsh32x32,
  2511  	{ir.OLSH, types.TUINT32, types.TUINT32}: ssa.OpLsh32x32,
  2512  	{ir.OLSH, types.TINT32, types.TUINT64}:  ssa.OpLsh32x64,
  2513  	{ir.OLSH, types.TUINT32, types.TUINT64}: ssa.OpLsh32x64,
  2514  
  2515  	{ir.OLSH, types.TINT64, types.TUINT8}:   ssa.OpLsh64x8,
  2516  	{ir.OLSH, types.TUINT64, types.TUINT8}:  ssa.OpLsh64x8,
  2517  	{ir.OLSH, types.TINT64, types.TUINT16}:  ssa.OpLsh64x16,
  2518  	{ir.OLSH, types.TUINT64, types.TUINT16}: ssa.OpLsh64x16,
  2519  	{ir.OLSH, types.TINT64, types.TUINT32}:  ssa.OpLsh64x32,
  2520  	{ir.OLSH, types.TUINT64, types.TUINT32}: ssa.OpLsh64x32,
  2521  	{ir.OLSH, types.TINT64, types.TUINT64}:  ssa.OpLsh64x64,
  2522  	{ir.OLSH, types.TUINT64, types.TUINT64}: ssa.OpLsh64x64,
  2523  
  2524  	{ir.ORSH, types.TINT8, types.TUINT8}:   ssa.OpRsh8x8,
  2525  	{ir.ORSH, types.TUINT8, types.TUINT8}:  ssa.OpRsh8Ux8,
  2526  	{ir.ORSH, types.TINT8, types.TUINT16}:  ssa.OpRsh8x16,
  2527  	{ir.ORSH, types.TUINT8, types.TUINT16}: ssa.OpRsh8Ux16,
  2528  	{ir.ORSH, types.TINT8, types.TUINT32}:  ssa.OpRsh8x32,
  2529  	{ir.ORSH, types.TUINT8, types.TUINT32}: ssa.OpRsh8Ux32,
  2530  	{ir.ORSH, types.TINT8, types.TUINT64}:  ssa.OpRsh8x64,
  2531  	{ir.ORSH, types.TUINT8, types.TUINT64}: ssa.OpRsh8Ux64,
  2532  
  2533  	{ir.ORSH, types.TINT16, types.TUINT8}:   ssa.OpRsh16x8,
  2534  	{ir.ORSH, types.TUINT16, types.TUINT8}:  ssa.OpRsh16Ux8,
  2535  	{ir.ORSH, types.TINT16, types.TUINT16}:  ssa.OpRsh16x16,
  2536  	{ir.ORSH, types.TUINT16, types.TUINT16}: ssa.OpRsh16Ux16,
  2537  	{ir.ORSH, types.TINT16, types.TUINT32}:  ssa.OpRsh16x32,
  2538  	{ir.ORSH, types.TUINT16, types.TUINT32}: ssa.OpRsh16Ux32,
  2539  	{ir.ORSH, types.TINT16, types.TUINT64}:  ssa.OpRsh16x64,
  2540  	{ir.ORSH, types.TUINT16, types.TUINT64}: ssa.OpRsh16Ux64,
  2541  
  2542  	{ir.ORSH, types.TINT32, types.TUINT8}:   ssa.OpRsh32x8,
  2543  	{ir.ORSH, types.TUINT32, types.TUINT8}:  ssa.OpRsh32Ux8,
  2544  	{ir.ORSH, types.TINT32, types.TUINT16}:  ssa.OpRsh32x16,
  2545  	{ir.ORSH, types.TUINT32, types.TUINT16}: ssa.OpRsh32Ux16,
  2546  	{ir.ORSH, types.TINT32, types.TUINT32}:  ssa.OpRsh32x32,
  2547  	{ir.ORSH, types.TUINT32, types.TUINT32}: ssa.OpRsh32Ux32,
  2548  	{ir.ORSH, types.TINT32, types.TUINT64}:  ssa.OpRsh32x64,
  2549  	{ir.ORSH, types.TUINT32, types.TUINT64}: ssa.OpRsh32Ux64,
  2550  
  2551  	{ir.ORSH, types.TINT64, types.TUINT8}:   ssa.OpRsh64x8,
  2552  	{ir.ORSH, types.TUINT64, types.TUINT8}:  ssa.OpRsh64Ux8,
  2553  	{ir.ORSH, types.TINT64, types.TUINT16}:  ssa.OpRsh64x16,
  2554  	{ir.ORSH, types.TUINT64, types.TUINT16}: ssa.OpRsh64Ux16,
  2555  	{ir.ORSH, types.TINT64, types.TUINT32}:  ssa.OpRsh64x32,
  2556  	{ir.ORSH, types.TUINT64, types.TUINT32}: ssa.OpRsh64Ux32,
  2557  	{ir.ORSH, types.TINT64, types.TUINT64}:  ssa.OpRsh64x64,
  2558  	{ir.ORSH, types.TUINT64, types.TUINT64}: ssa.OpRsh64Ux64,
  2559  }
  2560  
  2561  func (s *state) ssaShiftOp(op ir.Op, t *types.Type, u *types.Type) ssa.Op {
  2562  	etype1 := s.concreteEtype(t)
  2563  	etype2 := s.concreteEtype(u)
  2564  	x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
  2565  	if !ok {
  2566  		s.Fatalf("unhandled shift op %v etype=%s/%s", op, etype1, etype2)
  2567  	}
  2568  	return x
  2569  }
  2570  
  2571  func (s *state) uintptrConstant(v uint64) *ssa.Value {
  2572  	if s.config.PtrSize == 4 {
  2573  		return s.newValue0I(ssa.OpConst32, types.Types[types.TUINTPTR], int64(v))
  2574  	}
  2575  	return s.newValue0I(ssa.OpConst64, types.Types[types.TUINTPTR], int64(v))
  2576  }
  2577  
  2578  func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
  2579  	if ft.IsBoolean() && tt.IsKind(types.TUINT8) {
  2580  		// Bool -> uint8 is generated internally when indexing into runtime.staticbyte.
  2581  		return s.newValue1(ssa.OpCvtBoolToUint8, tt, v)
  2582  	}
  2583  	if ft.IsInteger() && tt.IsInteger() {
  2584  		var op ssa.Op
  2585  		if tt.Size() == ft.Size() {
  2586  			op = ssa.OpCopy
  2587  		} else if tt.Size() < ft.Size() {
  2588  			// truncation
  2589  			switch 10*ft.Size() + tt.Size() {
  2590  			case 21:
  2591  				op = ssa.OpTrunc16to8
  2592  			case 41:
  2593  				op = ssa.OpTrunc32to8
  2594  			case 42:
  2595  				op = ssa.OpTrunc32to16
  2596  			case 81:
  2597  				op = ssa.OpTrunc64to8
  2598  			case 82:
  2599  				op = ssa.OpTrunc64to16
  2600  			case 84:
  2601  				op = ssa.OpTrunc64to32
  2602  			default:
  2603  				s.Fatalf("weird integer truncation %v -> %v", ft, tt)
  2604  			}
  2605  		} else if ft.IsSigned() {
  2606  			// sign extension
  2607  			switch 10*ft.Size() + tt.Size() {
  2608  			case 12:
  2609  				op = ssa.OpSignExt8to16
  2610  			case 14:
  2611  				op = ssa.OpSignExt8to32
  2612  			case 18:
  2613  				op = ssa.OpSignExt8to64
  2614  			case 24:
  2615  				op = ssa.OpSignExt16to32
  2616  			case 28:
  2617  				op = ssa.OpSignExt16to64
  2618  			case 48:
  2619  				op = ssa.OpSignExt32to64
  2620  			default:
  2621  				s.Fatalf("bad integer sign extension %v -> %v", ft, tt)
  2622  			}
  2623  		} else {
  2624  			// zero extension
  2625  			switch 10*ft.Size() + tt.Size() {
  2626  			case 12:
  2627  				op = ssa.OpZeroExt8to16
  2628  			case 14:
  2629  				op = ssa.OpZeroExt8to32
  2630  			case 18:
  2631  				op = ssa.OpZeroExt8to64
  2632  			case 24:
  2633  				op = ssa.OpZeroExt16to32
  2634  			case 28:
  2635  				op = ssa.OpZeroExt16to64
  2636  			case 48:
  2637  				op = ssa.OpZeroExt32to64
  2638  			default:
  2639  				s.Fatalf("weird integer sign extension %v -> %v", ft, tt)
  2640  			}
  2641  		}
  2642  		return s.newValue1(op, tt, v)
  2643  	}
  2644  
  2645  	if ft.IsComplex() && tt.IsComplex() {
  2646  		var op ssa.Op
  2647  		if ft.Size() == tt.Size() {
  2648  			switch ft.Size() {
  2649  			case 8:
  2650  				op = ssa.OpRound32F
  2651  			case 16:
  2652  				op = ssa.OpRound64F
  2653  			default:
  2654  				s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2655  			}
  2656  		} else if ft.Size() == 8 && tt.Size() == 16 {
  2657  			op = ssa.OpCvt32Fto64F
  2658  		} else if ft.Size() == 16 && tt.Size() == 8 {
  2659  			op = ssa.OpCvt64Fto32F
  2660  		} else {
  2661  			s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2662  		}
  2663  		ftp := types.FloatForComplex(ft)
  2664  		ttp := types.FloatForComplex(tt)
  2665  		return s.newValue2(ssa.OpComplexMake, tt,
  2666  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, v)),
  2667  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, v)))
  2668  	}
  2669  
  2670  	if tt.IsComplex() { // and ft is not complex
  2671  		// Needed for generics support - can't happen in normal Go code.
  2672  		et := types.FloatForComplex(tt)
  2673  		v = s.conv(n, v, ft, et)
  2674  		return s.newValue2(ssa.OpComplexMake, tt, v, s.zeroVal(et))
  2675  	}
  2676  
  2677  	if ft.IsFloat() || tt.IsFloat() {
  2678  		conv, ok := fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]
  2679  		if s.config.RegSize == 4 && Arch.LinkArch.Family != sys.MIPS && !s.softFloat {
  2680  			if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2681  				conv = conv1
  2682  			}
  2683  		}
  2684  		if Arch.LinkArch.Family == sys.ARM64 || Arch.LinkArch.Family == sys.Wasm || Arch.LinkArch.Family == sys.S390X || s.softFloat {
  2685  			if conv1, ok1 := uint64fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2686  				conv = conv1
  2687  			}
  2688  		}
  2689  
  2690  		if Arch.LinkArch.Family == sys.MIPS && !s.softFloat {
  2691  			if ft.Size() == 4 && ft.IsInteger() && !ft.IsSigned() {
  2692  				// tt is float32 or float64, and ft is also unsigned
  2693  				if tt.Size() == 4 {
  2694  					return s.uint32Tofloat32(n, v, ft, tt)
  2695  				}
  2696  				if tt.Size() == 8 {
  2697  					return s.uint32Tofloat64(n, v, ft, tt)
  2698  				}
  2699  			} else if tt.Size() == 4 && tt.IsInteger() && !tt.IsSigned() {
  2700  				// ft is float32 or float64, and tt is unsigned integer
  2701  				if ft.Size() == 4 {
  2702  					return s.float32ToUint32(n, v, ft, tt)
  2703  				}
  2704  				if ft.Size() == 8 {
  2705  					return s.float64ToUint32(n, v, ft, tt)
  2706  				}
  2707  			}
  2708  		}
  2709  
  2710  		if !ok {
  2711  			s.Fatalf("weird float conversion %v -> %v", ft, tt)
  2712  		}
  2713  		op1, op2, it := conv.op1, conv.op2, conv.intermediateType
  2714  
  2715  		if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
  2716  			// normal case, not tripping over unsigned 64
  2717  			if op1 == ssa.OpCopy {
  2718  				if op2 == ssa.OpCopy {
  2719  					return v
  2720  				}
  2721  				return s.newValueOrSfCall1(op2, tt, v)
  2722  			}
  2723  			if op2 == ssa.OpCopy {
  2724  				return s.newValueOrSfCall1(op1, tt, v)
  2725  			}
  2726  			return s.newValueOrSfCall1(op2, tt, s.newValueOrSfCall1(op1, types.Types[it], v))
  2727  		}
  2728  		// Tricky 64-bit unsigned cases.
  2729  		if ft.IsInteger() {
  2730  			// tt is float32 or float64, and ft is also unsigned
  2731  			if tt.Size() == 4 {
  2732  				return s.uint64Tofloat32(n, v, ft, tt)
  2733  			}
  2734  			if tt.Size() == 8 {
  2735  				return s.uint64Tofloat64(n, v, ft, tt)
  2736  			}
  2737  			s.Fatalf("weird unsigned integer to float conversion %v -> %v", ft, tt)
  2738  		}
  2739  		// ft is float32 or float64, and tt is unsigned integer
  2740  		if ft.Size() == 4 {
  2741  			return s.float32ToUint64(n, v, ft, tt)
  2742  		}
  2743  		if ft.Size() == 8 {
  2744  			return s.float64ToUint64(n, v, ft, tt)
  2745  		}
  2746  		s.Fatalf("weird float to unsigned integer conversion %v -> %v", ft, tt)
  2747  		return nil
  2748  	}
  2749  
  2750  	s.Fatalf("unhandled OCONV %s -> %s", ft.Kind(), tt.Kind())
  2751  	return nil
  2752  }
  2753  
  2754  // expr converts the expression n to ssa, adds it to s and returns the ssa result.
  2755  func (s *state) expr(n ir.Node) *ssa.Value {
  2756  	return s.exprCheckPtr(n, true)
  2757  }
  2758  
  2759  func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {
  2760  	if ir.HasUniquePos(n) {
  2761  		// ONAMEs and named OLITERALs have the line number
  2762  		// of the decl, not the use. See issue 14742.
  2763  		s.pushLine(n.Pos())
  2764  		defer s.popLine()
  2765  	}
  2766  
  2767  	s.stmtList(n.Init())
  2768  	switch n.Op() {
  2769  	case ir.OBYTES2STRTMP:
  2770  		n := n.(*ir.ConvExpr)
  2771  		slice := s.expr(n.X)
  2772  		ptr := s.newValue1(ssa.OpSlicePtr, s.f.Config.Types.BytePtr, slice)
  2773  		len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  2774  		return s.newValue2(ssa.OpStringMake, n.Type(), ptr, len)
  2775  	case ir.OSTR2BYTESTMP:
  2776  		n := n.(*ir.ConvExpr)
  2777  		str := s.expr(n.X)
  2778  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, str)
  2779  		if !n.NonNil() {
  2780  			// We need to ensure []byte("") evaluates to []byte{}, and not []byte(nil).
  2781  			//
  2782  			// TODO(mdempsky): Investigate using "len != 0" instead of "ptr != nil".
  2783  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], ptr, s.constNil(ptr.Type))
  2784  			zerobase := s.newValue1A(ssa.OpAddr, ptr.Type, ir.Syms.Zerobase, s.sb)
  2785  			ptr = s.ternary(cond, ptr, zerobase)
  2786  		}
  2787  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], str)
  2788  		return s.newValue3(ssa.OpSliceMake, n.Type(), ptr, len, len)
  2789  	case ir.OCFUNC:
  2790  		n := n.(*ir.UnaryExpr)
  2791  		aux := n.X.(*ir.Name).Linksym()
  2792  		// OCFUNC is used to build function values, which must
  2793  		// always reference ABIInternal entry points.
  2794  		if aux.ABI() != obj.ABIInternal {
  2795  			s.Fatalf("expected ABIInternal: %v", aux.ABI())
  2796  		}
  2797  		return s.entryNewValue1A(ssa.OpAddr, n.Type(), aux, s.sb)
  2798  	case ir.ONAME:
  2799  		n := n.(*ir.Name)
  2800  		if n.Class == ir.PFUNC {
  2801  			// "value" of a function is the address of the function's closure
  2802  			sym := staticdata.FuncLinksym(n)
  2803  			return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(n.Type()), sym, s.sb)
  2804  		}
  2805  		if s.canSSA(n) {
  2806  			return s.variable(n, n.Type())
  2807  		}
  2808  		return s.load(n.Type(), s.addr(n))
  2809  	case ir.OLINKSYMOFFSET:
  2810  		n := n.(*ir.LinksymOffsetExpr)
  2811  		return s.load(n.Type(), s.addr(n))
  2812  	case ir.ONIL:
  2813  		n := n.(*ir.NilExpr)
  2814  		t := n.Type()
  2815  		switch {
  2816  		case t.IsSlice():
  2817  			return s.constSlice(t)
  2818  		case t.IsInterface():
  2819  			return s.constInterface(t)
  2820  		default:
  2821  			return s.constNil(t)
  2822  		}
  2823  	case ir.OLITERAL:
  2824  		switch u := n.Val(); u.Kind() {
  2825  		case constant.Int:
  2826  			i := ir.IntVal(n.Type(), u)
  2827  			switch n.Type().Size() {
  2828  			case 1:
  2829  				return s.constInt8(n.Type(), int8(i))
  2830  			case 2:
  2831  				return s.constInt16(n.Type(), int16(i))
  2832  			case 4:
  2833  				return s.constInt32(n.Type(), int32(i))
  2834  			case 8:
  2835  				return s.constInt64(n.Type(), i)
  2836  			default:
  2837  				s.Fatalf("bad integer size %d", n.Type().Size())
  2838  				return nil
  2839  			}
  2840  		case constant.String:
  2841  			i := constant.StringVal(u)
  2842  			if i == "" {
  2843  				return s.constEmptyString(n.Type())
  2844  			}
  2845  			return s.entryNewValue0A(ssa.OpConstString, n.Type(), ssa.StringToAux(i))
  2846  		case constant.Bool:
  2847  			return s.constBool(constant.BoolVal(u))
  2848  		case constant.Float:
  2849  			f, _ := constant.Float64Val(u)
  2850  			switch n.Type().Size() {
  2851  			case 4:
  2852  				return s.constFloat32(n.Type(), f)
  2853  			case 8:
  2854  				return s.constFloat64(n.Type(), f)
  2855  			default:
  2856  				s.Fatalf("bad float size %d", n.Type().Size())
  2857  				return nil
  2858  			}
  2859  		case constant.Complex:
  2860  			re, _ := constant.Float64Val(constant.Real(u))
  2861  			im, _ := constant.Float64Val(constant.Imag(u))
  2862  			switch n.Type().Size() {
  2863  			case 8:
  2864  				pt := types.Types[types.TFLOAT32]
  2865  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  2866  					s.constFloat32(pt, re),
  2867  					s.constFloat32(pt, im))
  2868  			case 16:
  2869  				pt := types.Types[types.TFLOAT64]
  2870  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  2871  					s.constFloat64(pt, re),
  2872  					s.constFloat64(pt, im))
  2873  			default:
  2874  				s.Fatalf("bad complex size %d", n.Type().Size())
  2875  				return nil
  2876  			}
  2877  		default:
  2878  			s.Fatalf("unhandled OLITERAL %v", u.Kind())
  2879  			return nil
  2880  		}
  2881  	case ir.OCONVNOP:
  2882  		n := n.(*ir.ConvExpr)
  2883  		to := n.Type()
  2884  		from := n.X.Type()
  2885  
  2886  		// Assume everything will work out, so set up our return value.
  2887  		// Anything interesting that happens from here is a fatal.
  2888  		x := s.expr(n.X)
  2889  		if to == from {
  2890  			return x
  2891  		}
  2892  
  2893  		// Special case for not confusing GC and liveness.
  2894  		// We don't want pointers accidentally classified
  2895  		// as not-pointers or vice-versa because of copy
  2896  		// elision.
  2897  		if to.IsPtrShaped() != from.IsPtrShaped() {
  2898  			return s.newValue2(ssa.OpConvert, to, x, s.mem())
  2899  		}
  2900  
  2901  		v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
  2902  
  2903  		// CONVNOP closure
  2904  		if to.Kind() == types.TFUNC && from.IsPtrShaped() {
  2905  			return v
  2906  		}
  2907  
  2908  		// named <--> unnamed type or typed <--> untyped const
  2909  		if from.Kind() == to.Kind() {
  2910  			return v
  2911  		}
  2912  
  2913  		// unsafe.Pointer <--> *T
  2914  		if to.IsUnsafePtr() && from.IsPtrShaped() || from.IsUnsafePtr() && to.IsPtrShaped() {
  2915  			if s.checkPtrEnabled && checkPtrOK && to.IsPtr() && from.IsUnsafePtr() {
  2916  				s.checkPtrAlignment(n, v, nil)
  2917  			}
  2918  			return v
  2919  		}
  2920  
  2921  		// map <--> *hmap
  2922  		if to.Kind() == types.TMAP && from == types.NewPtr(reflectdata.MapType()) {
  2923  			return v
  2924  		}
  2925  
  2926  		types.CalcSize(from)
  2927  		types.CalcSize(to)
  2928  		if from.Size() != to.Size() {
  2929  			s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Size(), to, to.Size())
  2930  			return nil
  2931  		}
  2932  		if etypesign(from.Kind()) != etypesign(to.Kind()) {
  2933  			s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Kind(), to, to.Kind())
  2934  			return nil
  2935  		}
  2936  
  2937  		if base.Flag.Cfg.Instrumenting {
  2938  			// These appear to be fine, but they fail the
  2939  			// integer constraint below, so okay them here.
  2940  			// Sample non-integer conversion: map[string]string -> *uint8
  2941  			return v
  2942  		}
  2943  
  2944  		if etypesign(from.Kind()) == 0 {
  2945  			s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
  2946  			return nil
  2947  		}
  2948  
  2949  		// integer, same width, same sign
  2950  		return v
  2951  
  2952  	case ir.OCONV:
  2953  		n := n.(*ir.ConvExpr)
  2954  		x := s.expr(n.X)
  2955  		return s.conv(n, x, n.X.Type(), n.Type())
  2956  
  2957  	case ir.ODOTTYPE:
  2958  		n := n.(*ir.TypeAssertExpr)
  2959  		res, _ := s.dottype(n, false)
  2960  		return res
  2961  
  2962  	case ir.ODYNAMICDOTTYPE:
  2963  		n := n.(*ir.DynamicTypeAssertExpr)
  2964  		res, _ := s.dynamicDottype(n, false)
  2965  		return res
  2966  
  2967  	// binary ops
  2968  	case ir.OLT, ir.OEQ, ir.ONE, ir.OLE, ir.OGE, ir.OGT:
  2969  		n := n.(*ir.BinaryExpr)
  2970  		a := s.expr(n.X)
  2971  		b := s.expr(n.Y)
  2972  		if n.X.Type().IsComplex() {
  2973  			pt := types.FloatForComplex(n.X.Type())
  2974  			op := s.ssaOp(ir.OEQ, pt)
  2975  			r := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
  2976  			i := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
  2977  			c := s.newValue2(ssa.OpAndB, types.Types[types.TBOOL], r, i)
  2978  			switch n.Op() {
  2979  			case ir.OEQ:
  2980  				return c
  2981  			case ir.ONE:
  2982  				return s.newValue1(ssa.OpNot, types.Types[types.TBOOL], c)
  2983  			default:
  2984  				s.Fatalf("ordered complex compare %v", n.Op())
  2985  			}
  2986  		}
  2987  
  2988  		// Convert OGE and OGT into OLE and OLT.
  2989  		op := n.Op()
  2990  		switch op {
  2991  		case ir.OGE:
  2992  			op, a, b = ir.OLE, b, a
  2993  		case ir.OGT:
  2994  			op, a, b = ir.OLT, b, a
  2995  		}
  2996  		if n.X.Type().IsFloat() {
  2997  			// float comparison
  2998  			return s.newValueOrSfCall2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  2999  		}
  3000  		// integer comparison
  3001  		return s.newValue2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3002  	case ir.OMUL:
  3003  		n := n.(*ir.BinaryExpr)
  3004  		a := s.expr(n.X)
  3005  		b := s.expr(n.Y)
  3006  		if n.Type().IsComplex() {
  3007  			mulop := ssa.OpMul64F
  3008  			addop := ssa.OpAdd64F
  3009  			subop := ssa.OpSub64F
  3010  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3011  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3012  
  3013  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3014  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3015  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3016  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3017  
  3018  			if pt != wt { // Widen for calculation
  3019  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3020  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3021  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3022  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3023  			}
  3024  
  3025  			xreal := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3026  			ximag := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, bimag), s.newValueOrSfCall2(mulop, wt, aimag, breal))
  3027  
  3028  			if pt != wt { // Narrow to store back
  3029  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3030  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3031  			}
  3032  
  3033  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3034  		}
  3035  
  3036  		if n.Type().IsFloat() {
  3037  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3038  		}
  3039  
  3040  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3041  
  3042  	case ir.ODIV:
  3043  		n := n.(*ir.BinaryExpr)
  3044  		a := s.expr(n.X)
  3045  		b := s.expr(n.Y)
  3046  		if n.Type().IsComplex() {
  3047  			// TODO this is not executed because the front-end substitutes a runtime call.
  3048  			// That probably ought to change; with modest optimization the widen/narrow
  3049  			// conversions could all be elided in larger expression trees.
  3050  			mulop := ssa.OpMul64F
  3051  			addop := ssa.OpAdd64F
  3052  			subop := ssa.OpSub64F
  3053  			divop := ssa.OpDiv64F
  3054  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3055  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3056  
  3057  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3058  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3059  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3060  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3061  
  3062  			if pt != wt { // Widen for calculation
  3063  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3064  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3065  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3066  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3067  			}
  3068  
  3069  			denom := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, breal, breal), s.newValueOrSfCall2(mulop, wt, bimag, bimag))
  3070  			xreal := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3071  			ximag := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, aimag, breal), s.newValueOrSfCall2(mulop, wt, areal, bimag))
  3072  
  3073  			// TODO not sure if this is best done in wide precision or narrow
  3074  			// Double-rounding might be an issue.
  3075  			// Note that the pre-SSA implementation does the entire calculation
  3076  			// in wide format, so wide is compatible.
  3077  			xreal = s.newValueOrSfCall2(divop, wt, xreal, denom)
  3078  			ximag = s.newValueOrSfCall2(divop, wt, ximag, denom)
  3079  
  3080  			if pt != wt { // Narrow to store back
  3081  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3082  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3083  			}
  3084  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3085  		}
  3086  		if n.Type().IsFloat() {
  3087  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3088  		}
  3089  		return s.intDivide(n, a, b)
  3090  	case ir.OMOD:
  3091  		n := n.(*ir.BinaryExpr)
  3092  		a := s.expr(n.X)
  3093  		b := s.expr(n.Y)
  3094  		return s.intDivide(n, a, b)
  3095  	case ir.OADD, ir.OSUB:
  3096  		n := n.(*ir.BinaryExpr)
  3097  		a := s.expr(n.X)
  3098  		b := s.expr(n.Y)
  3099  		if n.Type().IsComplex() {
  3100  			pt := types.FloatForComplex(n.Type())
  3101  			op := s.ssaOp(n.Op(), pt)
  3102  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3103  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
  3104  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
  3105  		}
  3106  		if n.Type().IsFloat() {
  3107  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3108  		}
  3109  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3110  	case ir.OAND, ir.OOR, ir.OXOR:
  3111  		n := n.(*ir.BinaryExpr)
  3112  		a := s.expr(n.X)
  3113  		b := s.expr(n.Y)
  3114  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3115  	case ir.OANDNOT:
  3116  		n := n.(*ir.BinaryExpr)
  3117  		a := s.expr(n.X)
  3118  		b := s.expr(n.Y)
  3119  		b = s.newValue1(s.ssaOp(ir.OBITNOT, b.Type), b.Type, b)
  3120  		return s.newValue2(s.ssaOp(ir.OAND, n.Type()), a.Type, a, b)
  3121  	case ir.OLSH, ir.ORSH:
  3122  		n := n.(*ir.BinaryExpr)
  3123  		a := s.expr(n.X)
  3124  		b := s.expr(n.Y)
  3125  		bt := b.Type
  3126  		if bt.IsSigned() {
  3127  			cmp := s.newValue2(s.ssaOp(ir.OLE, bt), types.Types[types.TBOOL], s.zeroVal(bt), b)
  3128  			s.check(cmp, ir.Syms.Panicshift)
  3129  			bt = bt.ToUnsigned()
  3130  		}
  3131  		return s.newValue2(s.ssaShiftOp(n.Op(), n.Type(), bt), a.Type, a, b)
  3132  	case ir.OANDAND, ir.OOROR:
  3133  		// To implement OANDAND (and OOROR), we introduce a
  3134  		// new temporary variable to hold the result. The
  3135  		// variable is associated with the OANDAND node in the
  3136  		// s.vars table (normally variables are only
  3137  		// associated with ONAME nodes). We convert
  3138  		//     A && B
  3139  		// to
  3140  		//     var = A
  3141  		//     if var {
  3142  		//         var = B
  3143  		//     }
  3144  		// Using var in the subsequent block introduces the
  3145  		// necessary phi variable.
  3146  		n := n.(*ir.LogicalExpr)
  3147  		el := s.expr(n.X)
  3148  		s.vars[n] = el
  3149  
  3150  		b := s.endBlock()
  3151  		b.Kind = ssa.BlockIf
  3152  		b.SetControl(el)
  3153  		// In theory, we should set b.Likely here based on context.
  3154  		// However, gc only gives us likeliness hints
  3155  		// in a single place, for plain OIF statements,
  3156  		// and passing around context is finnicky, so don't bother for now.
  3157  
  3158  		bRight := s.f.NewBlock(ssa.BlockPlain)
  3159  		bResult := s.f.NewBlock(ssa.BlockPlain)
  3160  		if n.Op() == ir.OANDAND {
  3161  			b.AddEdgeTo(bRight)
  3162  			b.AddEdgeTo(bResult)
  3163  		} else if n.Op() == ir.OOROR {
  3164  			b.AddEdgeTo(bResult)
  3165  			b.AddEdgeTo(bRight)
  3166  		}
  3167  
  3168  		s.startBlock(bRight)
  3169  		er := s.expr(n.Y)
  3170  		s.vars[n] = er
  3171  
  3172  		b = s.endBlock()
  3173  		b.AddEdgeTo(bResult)
  3174  
  3175  		s.startBlock(bResult)
  3176  		return s.variable(n, types.Types[types.TBOOL])
  3177  	case ir.OCOMPLEX:
  3178  		n := n.(*ir.BinaryExpr)
  3179  		r := s.expr(n.X)
  3180  		i := s.expr(n.Y)
  3181  		return s.newValue2(ssa.OpComplexMake, n.Type(), r, i)
  3182  
  3183  	// unary ops
  3184  	case ir.ONEG:
  3185  		n := n.(*ir.UnaryExpr)
  3186  		a := s.expr(n.X)
  3187  		if n.Type().IsComplex() {
  3188  			tp := types.FloatForComplex(n.Type())
  3189  			negop := s.ssaOp(n.Op(), tp)
  3190  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3191  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
  3192  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
  3193  		}
  3194  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3195  	case ir.ONOT, ir.OBITNOT:
  3196  		n := n.(*ir.UnaryExpr)
  3197  		a := s.expr(n.X)
  3198  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3199  	case ir.OIMAG, ir.OREAL:
  3200  		n := n.(*ir.UnaryExpr)
  3201  		a := s.expr(n.X)
  3202  		return s.newValue1(s.ssaOp(n.Op(), n.X.Type()), n.Type(), a)
  3203  	case ir.OPLUS:
  3204  		n := n.(*ir.UnaryExpr)
  3205  		return s.expr(n.X)
  3206  
  3207  	case ir.OADDR:
  3208  		n := n.(*ir.AddrExpr)
  3209  		return s.addr(n.X)
  3210  
  3211  	case ir.ORESULT:
  3212  		n := n.(*ir.ResultExpr)
  3213  		if s.prevCall == nil || s.prevCall.Op != ssa.OpStaticLECall && s.prevCall.Op != ssa.OpInterLECall && s.prevCall.Op != ssa.OpClosureLECall {
  3214  			panic("Expected to see a previous call")
  3215  		}
  3216  		which := n.Index
  3217  		if which == -1 {
  3218  			panic(fmt.Errorf("ORESULT %v does not match call %s", n, s.prevCall))
  3219  		}
  3220  		return s.resultOfCall(s.prevCall, which, n.Type())
  3221  
  3222  	case ir.ODEREF:
  3223  		n := n.(*ir.StarExpr)
  3224  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3225  		return s.load(n.Type(), p)
  3226  
  3227  	case ir.ODOT:
  3228  		n := n.(*ir.SelectorExpr)
  3229  		if n.X.Op() == ir.OSTRUCTLIT {
  3230  			// All literals with nonzero fields have already been
  3231  			// rewritten during walk. Any that remain are just T{}
  3232  			// or equivalents. Use the zero value.
  3233  			if !ir.IsZero(n.X) {
  3234  				s.Fatalf("literal with nonzero value in SSA: %v", n.X)
  3235  			}
  3236  			return s.zeroVal(n.Type())
  3237  		}
  3238  		// If n is addressable and can't be represented in
  3239  		// SSA, then load just the selected field. This
  3240  		// prevents false memory dependencies in race/msan/asan
  3241  		// instrumentation.
  3242  		if ir.IsAddressable(n) && !s.canSSA(n) {
  3243  			p := s.addr(n)
  3244  			return s.load(n.Type(), p)
  3245  		}
  3246  		v := s.expr(n.X)
  3247  		return s.newValue1I(ssa.OpStructSelect, n.Type(), int64(fieldIdx(n)), v)
  3248  
  3249  	case ir.ODOTPTR:
  3250  		n := n.(*ir.SelectorExpr)
  3251  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3252  		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset(), p)
  3253  		return s.load(n.Type(), p)
  3254  
  3255  	case ir.OINDEX:
  3256  		n := n.(*ir.IndexExpr)
  3257  		switch {
  3258  		case n.X.Type().IsString():
  3259  			if n.Bounded() && ir.IsConst(n.X, constant.String) && ir.IsConst(n.Index, constant.Int) {
  3260  				// Replace "abc"[1] with 'b'.
  3261  				// Delayed until now because "abc"[1] is not an ideal constant.
  3262  				// See test/fixedbugs/issue11370.go.
  3263  				return s.newValue0I(ssa.OpConst8, types.Types[types.TUINT8], int64(int8(ir.StringVal(n.X)[ir.Int64Val(n.Index)])))
  3264  			}
  3265  			a := s.expr(n.X)
  3266  			i := s.expr(n.Index)
  3267  			len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3268  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  3269  			ptrtyp := s.f.Config.Types.BytePtr
  3270  			ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
  3271  			if ir.IsConst(n.Index, constant.Int) {
  3272  				ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, ir.Int64Val(n.Index), ptr)
  3273  			} else {
  3274  				ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
  3275  			}
  3276  			return s.load(types.Types[types.TUINT8], ptr)
  3277  		case n.X.Type().IsSlice():
  3278  			p := s.addr(n)
  3279  			return s.load(n.X.Type().Elem(), p)
  3280  		case n.X.Type().IsArray():
  3281  			if ssa.CanSSA(n.X.Type()) {
  3282  				// SSA can handle arrays of length at most 1.
  3283  				bound := n.X.Type().NumElem()
  3284  				a := s.expr(n.X)
  3285  				i := s.expr(n.Index)
  3286  				if bound == 0 {
  3287  					// Bounds check will never succeed.  Might as well
  3288  					// use constants for the bounds check.
  3289  					z := s.constInt(types.Types[types.TINT], 0)
  3290  					s.boundsCheck(z, z, ssa.BoundsIndex, false)
  3291  					// The return value won't be live, return junk.
  3292  					// But not quite junk, in case bounds checks are turned off. See issue 48092.
  3293  					return s.zeroVal(n.Type())
  3294  				}
  3295  				len := s.constInt(types.Types[types.TINT], bound)
  3296  				s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded()) // checks i == 0
  3297  				return s.newValue1I(ssa.OpArraySelect, n.Type(), 0, a)
  3298  			}
  3299  			p := s.addr(n)
  3300  			return s.load(n.X.Type().Elem(), p)
  3301  		default:
  3302  			s.Fatalf("bad type for index %v", n.X.Type())
  3303  			return nil
  3304  		}
  3305  
  3306  	case ir.OLEN, ir.OCAP:
  3307  		n := n.(*ir.UnaryExpr)
  3308  		switch {
  3309  		case n.X.Type().IsSlice():
  3310  			op := ssa.OpSliceLen
  3311  			if n.Op() == ir.OCAP {
  3312  				op = ssa.OpSliceCap
  3313  			}
  3314  			return s.newValue1(op, types.Types[types.TINT], s.expr(n.X))
  3315  		case n.X.Type().IsString(): // string; not reachable for OCAP
  3316  			return s.newValue1(ssa.OpStringLen, types.Types[types.TINT], s.expr(n.X))
  3317  		case n.X.Type().IsMap(), n.X.Type().IsChan():
  3318  			return s.referenceTypeBuiltin(n, s.expr(n.X))
  3319  		default: // array
  3320  			return s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  3321  		}
  3322  
  3323  	case ir.OSPTR:
  3324  		n := n.(*ir.UnaryExpr)
  3325  		a := s.expr(n.X)
  3326  		if n.X.Type().IsSlice() {
  3327  			if n.Bounded() {
  3328  				return s.newValue1(ssa.OpSlicePtr, n.Type(), a)
  3329  			}
  3330  			return s.newValue1(ssa.OpSlicePtrUnchecked, n.Type(), a)
  3331  		} else {
  3332  			return s.newValue1(ssa.OpStringPtr, n.Type(), a)
  3333  		}
  3334  
  3335  	case ir.OITAB:
  3336  		n := n.(*ir.UnaryExpr)
  3337  		a := s.expr(n.X)
  3338  		return s.newValue1(ssa.OpITab, n.Type(), a)
  3339  
  3340  	case ir.OIDATA:
  3341  		n := n.(*ir.UnaryExpr)
  3342  		a := s.expr(n.X)
  3343  		return s.newValue1(ssa.OpIData, n.Type(), a)
  3344  
  3345  	case ir.OMAKEFACE:
  3346  		n := n.(*ir.BinaryExpr)
  3347  		tab := s.expr(n.X)
  3348  		data := s.expr(n.Y)
  3349  		return s.newValue2(ssa.OpIMake, n.Type(), tab, data)
  3350  
  3351  	case ir.OSLICEHEADER:
  3352  		n := n.(*ir.SliceHeaderExpr)
  3353  		p := s.expr(n.Ptr)
  3354  		l := s.expr(n.Len)
  3355  		c := s.expr(n.Cap)
  3356  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3357  
  3358  	case ir.OSTRINGHEADER:
  3359  		n := n.(*ir.StringHeaderExpr)
  3360  		p := s.expr(n.Ptr)
  3361  		l := s.expr(n.Len)
  3362  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3363  
  3364  	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR:
  3365  		n := n.(*ir.SliceExpr)
  3366  		check := s.checkPtrEnabled && n.Op() == ir.OSLICE3ARR && n.X.Op() == ir.OCONVNOP && n.X.(*ir.ConvExpr).X.Type().IsUnsafePtr()
  3367  		v := s.exprCheckPtr(n.X, !check)
  3368  		var i, j, k *ssa.Value
  3369  		if n.Low != nil {
  3370  			i = s.expr(n.Low)
  3371  		}
  3372  		if n.High != nil {
  3373  			j = s.expr(n.High)
  3374  		}
  3375  		if n.Max != nil {
  3376  			k = s.expr(n.Max)
  3377  		}
  3378  		p, l, c := s.slice(v, i, j, k, n.Bounded())
  3379  		if check {
  3380  			// Emit checkptr instrumentation after bound check to prevent false positive, see #46938.
  3381  			s.checkPtrAlignment(n.X.(*ir.ConvExpr), v, s.conv(n.Max, k, k.Type, types.Types[types.TUINTPTR]))
  3382  		}
  3383  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3384  
  3385  	case ir.OSLICESTR:
  3386  		n := n.(*ir.SliceExpr)
  3387  		v := s.expr(n.X)
  3388  		var i, j *ssa.Value
  3389  		if n.Low != nil {
  3390  			i = s.expr(n.Low)
  3391  		}
  3392  		if n.High != nil {
  3393  			j = s.expr(n.High)
  3394  		}
  3395  		p, l, _ := s.slice(v, i, j, nil, n.Bounded())
  3396  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3397  
  3398  	case ir.OSLICE2ARRPTR:
  3399  		// if arrlen > slice.len {
  3400  		//   panic(...)
  3401  		// }
  3402  		// slice.ptr
  3403  		n := n.(*ir.ConvExpr)
  3404  		v := s.expr(n.X)
  3405  		nelem := n.Type().Elem().NumElem()
  3406  		arrlen := s.constInt(types.Types[types.TINT], nelem)
  3407  		cap := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  3408  		s.boundsCheck(arrlen, cap, ssa.BoundsConvert, false)
  3409  		op := ssa.OpSlicePtr
  3410  		if nelem == 0 {
  3411  			op = ssa.OpSlicePtrUnchecked
  3412  		}
  3413  		return s.newValue1(op, n.Type(), v)
  3414  
  3415  	case ir.OCALLFUNC:
  3416  		n := n.(*ir.CallExpr)
  3417  		if ir.IsIntrinsicCall(n) {
  3418  			return s.intrinsicCall(n)
  3419  		}
  3420  		fallthrough
  3421  
  3422  	case ir.OCALLINTER:
  3423  		n := n.(*ir.CallExpr)
  3424  		return s.callResult(n, callNormal)
  3425  
  3426  	case ir.OGETG:
  3427  		n := n.(*ir.CallExpr)
  3428  		return s.newValue1(ssa.OpGetG, n.Type(), s.mem())
  3429  
  3430  	case ir.OGETCALLERPC:
  3431  		n := n.(*ir.CallExpr)
  3432  		return s.newValue0(ssa.OpGetCallerPC, n.Type())
  3433  
  3434  	case ir.OGETCALLERSP:
  3435  		n := n.(*ir.CallExpr)
  3436  		return s.newValue1(ssa.OpGetCallerSP, n.Type(), s.mem())
  3437  
  3438  	case ir.OAPPEND:
  3439  		return s.append(n.(*ir.CallExpr), false)
  3440  
  3441  	case ir.OMIN, ir.OMAX:
  3442  		return s.minMax(n.(*ir.CallExpr))
  3443  
  3444  	case ir.OSTRUCTLIT, ir.OARRAYLIT:
  3445  		// All literals with nonzero fields have already been
  3446  		// rewritten during walk. Any that remain are just T{}
  3447  		// or equivalents. Use the zero value.
  3448  		n := n.(*ir.CompLitExpr)
  3449  		if !ir.IsZero(n) {
  3450  			s.Fatalf("literal with nonzero value in SSA: %v", n)
  3451  		}
  3452  		return s.zeroVal(n.Type())
  3453  
  3454  	case ir.ONEW:
  3455  		n := n.(*ir.UnaryExpr)
  3456  		var rtype *ssa.Value
  3457  		if x, ok := n.X.(*ir.DynamicType); ok && x.Op() == ir.ODYNAMICTYPE {
  3458  			rtype = s.expr(x.RType)
  3459  		}
  3460  		return s.newObject(n.Type().Elem(), rtype)
  3461  
  3462  	case ir.OUNSAFEADD:
  3463  		n := n.(*ir.BinaryExpr)
  3464  		ptr := s.expr(n.X)
  3465  		len := s.expr(n.Y)
  3466  
  3467  		// Force len to uintptr to prevent misuse of garbage bits in the
  3468  		// upper part of the register (#48536).
  3469  		len = s.conv(n, len, len.Type, types.Types[types.TUINTPTR])
  3470  
  3471  		return s.newValue2(ssa.OpAddPtr, n.Type(), ptr, len)
  3472  
  3473  	default:
  3474  		s.Fatalf("unhandled expr %v", n.Op())
  3475  		return nil
  3476  	}
  3477  }
  3478  
  3479  func (s *state) resultOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3480  	aux := c.Aux.(*ssa.AuxCall)
  3481  	pa := aux.ParamAssignmentForResult(which)
  3482  	// TODO(register args) determine if in-memory TypeOK is better loaded early from SelectNAddr or later when SelectN is expanded.
  3483  	// SelectN is better for pattern-matching and possible call-aware analysis we might want to do in the future.
  3484  	if len(pa.Registers) == 0 && !ssa.CanSSA(t) {
  3485  		addr := s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3486  		return s.rawLoad(t, addr)
  3487  	}
  3488  	return s.newValue1I(ssa.OpSelectN, t, which, c)
  3489  }
  3490  
  3491  func (s *state) resultAddrOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3492  	aux := c.Aux.(*ssa.AuxCall)
  3493  	pa := aux.ParamAssignmentForResult(which)
  3494  	if len(pa.Registers) == 0 {
  3495  		return s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3496  	}
  3497  	_, addr := s.temp(c.Pos, t)
  3498  	rval := s.newValue1I(ssa.OpSelectN, t, which, c)
  3499  	s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, addr, rval, s.mem(), false)
  3500  	return addr
  3501  }
  3502  
  3503  // append converts an OAPPEND node to SSA.
  3504  // If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
  3505  // adds it to s, and returns the Value.
  3506  // If inplace is true, it writes the result of the OAPPEND expression n
  3507  // back to the slice being appended to, and returns nil.
  3508  // inplace MUST be set to false if the slice can be SSA'd.
  3509  // Note: this code only handles fixed-count appends. Dotdotdot appends
  3510  // have already been rewritten at this point (by walk).
  3511  func (s *state) append(n *ir.CallExpr, inplace bool) *ssa.Value {
  3512  	// If inplace is false, process as expression "append(s, e1, e2, e3)":
  3513  	//
  3514  	// ptr, len, cap := s
  3515  	// len += 3
  3516  	// if uint(len) > uint(cap) {
  3517  	//     ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3518  	//     Note that len is unmodified by growslice.
  3519  	// }
  3520  	// // with write barriers, if needed:
  3521  	// *(ptr+(len-3)) = e1
  3522  	// *(ptr+(len-2)) = e2
  3523  	// *(ptr+(len-1)) = e3
  3524  	// return makeslice(ptr, len, cap)
  3525  	//
  3526  	//
  3527  	// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
  3528  	//
  3529  	// a := &s
  3530  	// ptr, len, cap := s
  3531  	// len += 3
  3532  	// if uint(len) > uint(cap) {
  3533  	//    ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3534  	//    vardef(a)    // if necessary, advise liveness we are writing a new a
  3535  	//    *a.cap = cap // write before ptr to avoid a spill
  3536  	//    *a.ptr = ptr // with write barrier
  3537  	// }
  3538  	// *a.len = len
  3539  	// // with write barriers, if needed:
  3540  	// *(ptr+(len-3)) = e1
  3541  	// *(ptr+(len-2)) = e2
  3542  	// *(ptr+(len-1)) = e3
  3543  
  3544  	et := n.Type().Elem()
  3545  	pt := types.NewPtr(et)
  3546  
  3547  	// Evaluate slice
  3548  	sn := n.Args[0] // the slice node is the first in the list
  3549  	var slice, addr *ssa.Value
  3550  	if inplace {
  3551  		addr = s.addr(sn)
  3552  		slice = s.load(n.Type(), addr)
  3553  	} else {
  3554  		slice = s.expr(sn)
  3555  	}
  3556  
  3557  	// Allocate new blocks
  3558  	grow := s.f.NewBlock(ssa.BlockPlain)
  3559  	assign := s.f.NewBlock(ssa.BlockPlain)
  3560  
  3561  	// Decomposse input slice.
  3562  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  3563  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3564  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  3565  
  3566  	// Add number of new elements to length.
  3567  	nargs := s.constInt(types.Types[types.TINT], int64(len(n.Args)-1))
  3568  	l = s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  3569  
  3570  	// Decide if we need to grow
  3571  	cmp := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT]), types.Types[types.TBOOL], c, l)
  3572  
  3573  	// Record values of ptr/len/cap before branch.
  3574  	s.vars[ptrVar] = p
  3575  	s.vars[lenVar] = l
  3576  	if !inplace {
  3577  		s.vars[capVar] = c
  3578  	}
  3579  
  3580  	b := s.endBlock()
  3581  	b.Kind = ssa.BlockIf
  3582  	b.Likely = ssa.BranchUnlikely
  3583  	b.SetControl(cmp)
  3584  	b.AddEdgeTo(grow)
  3585  	b.AddEdgeTo(assign)
  3586  
  3587  	// Call growslice
  3588  	s.startBlock(grow)
  3589  	taddr := s.expr(n.Fun)
  3590  	r := s.rtcall(ir.Syms.Growslice, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr)
  3591  
  3592  	// Decompose output slice
  3593  	p = s.newValue1(ssa.OpSlicePtr, pt, r[0])
  3594  	l = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], r[0])
  3595  	c = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], r[0])
  3596  
  3597  	s.vars[ptrVar] = p
  3598  	s.vars[lenVar] = l
  3599  	s.vars[capVar] = c
  3600  	if inplace {
  3601  		if sn.Op() == ir.ONAME {
  3602  			sn := sn.(*ir.Name)
  3603  			if sn.Class != ir.PEXTERN {
  3604  				// Tell liveness we're about to build a new slice
  3605  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, sn, s.mem())
  3606  			}
  3607  		}
  3608  		capaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceCapOffset, addr)
  3609  		s.store(types.Types[types.TINT], capaddr, c)
  3610  		s.store(pt, addr, p)
  3611  	}
  3612  
  3613  	b = s.endBlock()
  3614  	b.AddEdgeTo(assign)
  3615  
  3616  	// assign new elements to slots
  3617  	s.startBlock(assign)
  3618  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  3619  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  3620  	if !inplace {
  3621  		c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  3622  	}
  3623  
  3624  	if inplace {
  3625  		// Update length in place.
  3626  		// We have to wait until here to make sure growslice succeeded.
  3627  		lenaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceLenOffset, addr)
  3628  		s.store(types.Types[types.TINT], lenaddr, l)
  3629  	}
  3630  
  3631  	// Evaluate args
  3632  	type argRec struct {
  3633  		// if store is true, we're appending the value v.  If false, we're appending the
  3634  		// value at *v.
  3635  		v     *ssa.Value
  3636  		store bool
  3637  	}
  3638  	args := make([]argRec, 0, len(n.Args[1:]))
  3639  	for _, n := range n.Args[1:] {
  3640  		if ssa.CanSSA(n.Type()) {
  3641  			args = append(args, argRec{v: s.expr(n), store: true})
  3642  		} else {
  3643  			v := s.addr(n)
  3644  			args = append(args, argRec{v: v})
  3645  		}
  3646  	}
  3647  
  3648  	// Write args into slice.
  3649  	oldLen := s.newValue2(s.ssaOp(ir.OSUB, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  3650  	p2 := s.newValue2(ssa.OpPtrIndex, pt, p, oldLen)
  3651  	for i, arg := range args {
  3652  		addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(types.Types[types.TINT], int64(i)))
  3653  		if arg.store {
  3654  			s.storeType(et, addr, arg.v, 0, true)
  3655  		} else {
  3656  			s.move(et, addr, arg.v)
  3657  		}
  3658  	}
  3659  
  3660  	// The following deletions have no practical effect at this time
  3661  	// because state.vars has been reset by the preceding state.startBlock.
  3662  	// They only enforce the fact that these variables are no longer need in
  3663  	// the current scope.
  3664  	delete(s.vars, ptrVar)
  3665  	delete(s.vars, lenVar)
  3666  	if !inplace {
  3667  		delete(s.vars, capVar)
  3668  	}
  3669  
  3670  	// make result
  3671  	if inplace {
  3672  		return nil
  3673  	}
  3674  	return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3675  }
  3676  
  3677  // minMax converts an OMIN/OMAX builtin call into SSA.
  3678  func (s *state) minMax(n *ir.CallExpr) *ssa.Value {
  3679  	// The OMIN/OMAX builtin is variadic, but its semantics are
  3680  	// equivalent to left-folding a binary min/max operation across the
  3681  	// arguments list.
  3682  	fold := func(op func(x, a *ssa.Value) *ssa.Value) *ssa.Value {
  3683  		x := s.expr(n.Args[0])
  3684  		for _, arg := range n.Args[1:] {
  3685  			x = op(x, s.expr(arg))
  3686  		}
  3687  		return x
  3688  	}
  3689  
  3690  	typ := n.Type()
  3691  
  3692  	if typ.IsFloat() || typ.IsString() {
  3693  		// min/max semantics for floats are tricky because of NaNs and
  3694  		// negative zero. Some architectures have instructions which
  3695  		// we can use to generate the right result. For others we must
  3696  		// call into the runtime instead.
  3697  		//
  3698  		// Strings are conceptually simpler, but we currently desugar
  3699  		// string comparisons during walk, not ssagen.
  3700  
  3701  		if typ.IsFloat() {
  3702  			switch Arch.LinkArch.Family {
  3703  			case sys.AMD64, sys.ARM64:
  3704  				var op ssa.Op
  3705  				switch {
  3706  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMIN:
  3707  					op = ssa.OpMin64F
  3708  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMAX:
  3709  					op = ssa.OpMax64F
  3710  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMIN:
  3711  					op = ssa.OpMin32F
  3712  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMAX:
  3713  					op = ssa.OpMax32F
  3714  				}
  3715  				return fold(func(x, a *ssa.Value) *ssa.Value {
  3716  					return s.newValue2(op, typ, x, a)
  3717  				})
  3718  			}
  3719  		}
  3720  		var name string
  3721  		switch typ.Kind() {
  3722  		case types.TFLOAT32:
  3723  			switch n.Op() {
  3724  			case ir.OMIN:
  3725  				name = "fmin32"
  3726  			case ir.OMAX:
  3727  				name = "fmax32"
  3728  			}
  3729  		case types.TFLOAT64:
  3730  			switch n.Op() {
  3731  			case ir.OMIN:
  3732  				name = "fmin64"
  3733  			case ir.OMAX:
  3734  				name = "fmax64"
  3735  			}
  3736  		case types.TSTRING:
  3737  			switch n.Op() {
  3738  			case ir.OMIN:
  3739  				name = "strmin"
  3740  			case ir.OMAX:
  3741  				name = "strmax"
  3742  			}
  3743  		}
  3744  		fn := typecheck.LookupRuntimeFunc(name)
  3745  
  3746  		return fold(func(x, a *ssa.Value) *ssa.Value {
  3747  			return s.rtcall(fn, true, []*types.Type{typ}, x, a)[0]
  3748  		})
  3749  	}
  3750  
  3751  	lt := s.ssaOp(ir.OLT, typ)
  3752  
  3753  	return fold(func(x, a *ssa.Value) *ssa.Value {
  3754  		switch n.Op() {
  3755  		case ir.OMIN:
  3756  			// a < x ? a : x
  3757  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], a, x), a, x)
  3758  		case ir.OMAX:
  3759  			// x < a ? a : x
  3760  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], x, a), a, x)
  3761  		}
  3762  		panic("unreachable")
  3763  	})
  3764  }
  3765  
  3766  // ternary emits code to evaluate cond ? x : y.
  3767  func (s *state) ternary(cond, x, y *ssa.Value) *ssa.Value {
  3768  	// Note that we need a new ternaryVar each time (unlike okVar where we can
  3769  	// reuse the variable) because it might have a different type every time.
  3770  	ternaryVar := ssaMarker("ternary")
  3771  
  3772  	bThen := s.f.NewBlock(ssa.BlockPlain)
  3773  	bElse := s.f.NewBlock(ssa.BlockPlain)
  3774  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  3775  
  3776  	b := s.endBlock()
  3777  	b.Kind = ssa.BlockIf
  3778  	b.SetControl(cond)
  3779  	b.AddEdgeTo(bThen)
  3780  	b.AddEdgeTo(bElse)
  3781  
  3782  	s.startBlock(bThen)
  3783  	s.vars[ternaryVar] = x
  3784  	s.endBlock().AddEdgeTo(bEnd)
  3785  
  3786  	s.startBlock(bElse)
  3787  	s.vars[ternaryVar] = y
  3788  	s.endBlock().AddEdgeTo(bEnd)
  3789  
  3790  	s.startBlock(bEnd)
  3791  	r := s.variable(ternaryVar, x.Type)
  3792  	delete(s.vars, ternaryVar)
  3793  	return r
  3794  }
  3795  
  3796  // condBranch evaluates the boolean expression cond and branches to yes
  3797  // if cond is true and no if cond is false.
  3798  // This function is intended to handle && and || better than just calling
  3799  // s.expr(cond) and branching on the result.
  3800  func (s *state) condBranch(cond ir.Node, yes, no *ssa.Block, likely int8) {
  3801  	switch cond.Op() {
  3802  	case ir.OANDAND:
  3803  		cond := cond.(*ir.LogicalExpr)
  3804  		mid := s.f.NewBlock(ssa.BlockPlain)
  3805  		s.stmtList(cond.Init())
  3806  		s.condBranch(cond.X, mid, no, max8(likely, 0))
  3807  		s.startBlock(mid)
  3808  		s.condBranch(cond.Y, yes, no, likely)
  3809  		return
  3810  		// Note: if likely==1, then both recursive calls pass 1.
  3811  		// If likely==-1, then we don't have enough information to decide
  3812  		// whether the first branch is likely or not. So we pass 0 for
  3813  		// the likeliness of the first branch.
  3814  		// TODO: have the frontend give us branch prediction hints for
  3815  		// OANDAND and OOROR nodes (if it ever has such info).
  3816  	case ir.OOROR:
  3817  		cond := cond.(*ir.LogicalExpr)
  3818  		mid := s.f.NewBlock(ssa.BlockPlain)
  3819  		s.stmtList(cond.Init())
  3820  		s.condBranch(cond.X, yes, mid, min8(likely, 0))
  3821  		s.startBlock(mid)
  3822  		s.condBranch(cond.Y, yes, no, likely)
  3823  		return
  3824  		// Note: if likely==-1, then both recursive calls pass -1.
  3825  		// If likely==1, then we don't have enough info to decide
  3826  		// the likelihood of the first branch.
  3827  	case ir.ONOT:
  3828  		cond := cond.(*ir.UnaryExpr)
  3829  		s.stmtList(cond.Init())
  3830  		s.condBranch(cond.X, no, yes, -likely)
  3831  		return
  3832  	case ir.OCONVNOP:
  3833  		cond := cond.(*ir.ConvExpr)
  3834  		s.stmtList(cond.Init())
  3835  		s.condBranch(cond.X, yes, no, likely)
  3836  		return
  3837  	}
  3838  	c := s.expr(cond)
  3839  	b := s.endBlock()
  3840  	b.Kind = ssa.BlockIf
  3841  	b.SetControl(c)
  3842  	b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
  3843  	b.AddEdgeTo(yes)
  3844  	b.AddEdgeTo(no)
  3845  }
  3846  
  3847  type skipMask uint8
  3848  
  3849  const (
  3850  	skipPtr skipMask = 1 << iota
  3851  	skipLen
  3852  	skipCap
  3853  )
  3854  
  3855  // assign does left = right.
  3856  // Right has already been evaluated to ssa, left has not.
  3857  // If deref is true, then we do left = *right instead (and right has already been nil-checked).
  3858  // If deref is true and right == nil, just do left = 0.
  3859  // skip indicates assignments (at the top level) that can be avoided.
  3860  // mayOverlap indicates whether left&right might partially overlap in memory. Default is false.
  3861  func (s *state) assign(left ir.Node, right *ssa.Value, deref bool, skip skipMask) {
  3862  	s.assignWhichMayOverlap(left, right, deref, skip, false)
  3863  }
  3864  func (s *state) assignWhichMayOverlap(left ir.Node, right *ssa.Value, deref bool, skip skipMask, mayOverlap bool) {
  3865  	if left.Op() == ir.ONAME && ir.IsBlank(left) {
  3866  		return
  3867  	}
  3868  	t := left.Type()
  3869  	types.CalcSize(t)
  3870  	if s.canSSA(left) {
  3871  		if deref {
  3872  			s.Fatalf("can SSA LHS %v but not RHS %s", left, right)
  3873  		}
  3874  		if left.Op() == ir.ODOT {
  3875  			// We're assigning to a field of an ssa-able value.
  3876  			// We need to build a new structure with the new value for the
  3877  			// field we're assigning and the old values for the other fields.
  3878  			// For instance:
  3879  			//   type T struct {a, b, c int}
  3880  			//   var T x
  3881  			//   x.b = 5
  3882  			// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
  3883  
  3884  			// Grab information about the structure type.
  3885  			left := left.(*ir.SelectorExpr)
  3886  			t := left.X.Type()
  3887  			nf := t.NumFields()
  3888  			idx := fieldIdx(left)
  3889  
  3890  			// Grab old value of structure.
  3891  			old := s.expr(left.X)
  3892  
  3893  			// Make new structure.
  3894  			new := s.newValue0(ssa.StructMakeOp(t.NumFields()), t)
  3895  
  3896  			// Add fields as args.
  3897  			for i := 0; i < nf; i++ {
  3898  				if i == idx {
  3899  					new.AddArg(right)
  3900  				} else {
  3901  					new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
  3902  				}
  3903  			}
  3904  
  3905  			// Recursively assign the new value we've made to the base of the dot op.
  3906  			s.assign(left.X, new, false, 0)
  3907  			// TODO: do we need to update named values here?
  3908  			return
  3909  		}
  3910  		if left.Op() == ir.OINDEX && left.(*ir.IndexExpr).X.Type().IsArray() {
  3911  			left := left.(*ir.IndexExpr)
  3912  			s.pushLine(left.Pos())
  3913  			defer s.popLine()
  3914  			// We're assigning to an element of an ssa-able array.
  3915  			// a[i] = v
  3916  			t := left.X.Type()
  3917  			n := t.NumElem()
  3918  
  3919  			i := s.expr(left.Index) // index
  3920  			if n == 0 {
  3921  				// The bounds check must fail.  Might as well
  3922  				// ignore the actual index and just use zeros.
  3923  				z := s.constInt(types.Types[types.TINT], 0)
  3924  				s.boundsCheck(z, z, ssa.BoundsIndex, false)
  3925  				return
  3926  			}
  3927  			if n != 1 {
  3928  				s.Fatalf("assigning to non-1-length array")
  3929  			}
  3930  			// Rewrite to a = [1]{v}
  3931  			len := s.constInt(types.Types[types.TINT], 1)
  3932  			s.boundsCheck(i, len, ssa.BoundsIndex, false) // checks i == 0
  3933  			v := s.newValue1(ssa.OpArrayMake1, t, right)
  3934  			s.assign(left.X, v, false, 0)
  3935  			return
  3936  		}
  3937  		left := left.(*ir.Name)
  3938  		// Update variable assignment.
  3939  		s.vars[left] = right
  3940  		s.addNamedValue(left, right)
  3941  		return
  3942  	}
  3943  
  3944  	// If this assignment clobbers an entire local variable, then emit
  3945  	// OpVarDef so liveness analysis knows the variable is redefined.
  3946  	if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 && t.HasPointers() {
  3947  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base))
  3948  	}
  3949  
  3950  	// Left is not ssa-able. Compute its address.
  3951  	addr := s.addr(left)
  3952  	if ir.IsReflectHeaderDataField(left) {
  3953  		// Package unsafe's documentation says storing pointers into
  3954  		// reflect.SliceHeader and reflect.StringHeader's Data fields
  3955  		// is valid, even though they have type uintptr (#19168).
  3956  		// Mark it pointer type to signal the writebarrier pass to
  3957  		// insert a write barrier.
  3958  		t = types.Types[types.TUNSAFEPTR]
  3959  	}
  3960  	if deref {
  3961  		// Treat as a mem->mem move.
  3962  		if right == nil {
  3963  			s.zero(t, addr)
  3964  		} else {
  3965  			s.moveWhichMayOverlap(t, addr, right, mayOverlap)
  3966  		}
  3967  		return
  3968  	}
  3969  	// Treat as a store.
  3970  	s.storeType(t, addr, right, skip, !ir.IsAutoTmp(left))
  3971  }
  3972  
  3973  // zeroVal returns the zero value for type t.
  3974  func (s *state) zeroVal(t *types.Type) *ssa.Value {
  3975  	switch {
  3976  	case t.IsInteger():
  3977  		switch t.Size() {
  3978  		case 1:
  3979  			return s.constInt8(t, 0)
  3980  		case 2:
  3981  			return s.constInt16(t, 0)
  3982  		case 4:
  3983  			return s.constInt32(t, 0)
  3984  		case 8:
  3985  			return s.constInt64(t, 0)
  3986  		default:
  3987  			s.Fatalf("bad sized integer type %v", t)
  3988  		}
  3989  	case t.IsFloat():
  3990  		switch t.Size() {
  3991  		case 4:
  3992  			return s.constFloat32(t, 0)
  3993  		case 8:
  3994  			return s.constFloat64(t, 0)
  3995  		default:
  3996  			s.Fatalf("bad sized float type %v", t)
  3997  		}
  3998  	case t.IsComplex():
  3999  		switch t.Size() {
  4000  		case 8:
  4001  			z := s.constFloat32(types.Types[types.TFLOAT32], 0)
  4002  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4003  		case 16:
  4004  			z := s.constFloat64(types.Types[types.TFLOAT64], 0)
  4005  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4006  		default:
  4007  			s.Fatalf("bad sized complex type %v", t)
  4008  		}
  4009  
  4010  	case t.IsString():
  4011  		return s.constEmptyString(t)
  4012  	case t.IsPtrShaped():
  4013  		return s.constNil(t)
  4014  	case t.IsBoolean():
  4015  		return s.constBool(false)
  4016  	case t.IsInterface():
  4017  		return s.constInterface(t)
  4018  	case t.IsSlice():
  4019  		return s.constSlice(t)
  4020  	case t.IsStruct():
  4021  		n := t.NumFields()
  4022  		v := s.entryNewValue0(ssa.StructMakeOp(t.NumFields()), t)
  4023  		for i := 0; i < n; i++ {
  4024  			v.AddArg(s.zeroVal(t.FieldType(i)))
  4025  		}
  4026  		return v
  4027  	case t.IsArray():
  4028  		switch t.NumElem() {
  4029  		case 0:
  4030  			return s.entryNewValue0(ssa.OpArrayMake0, t)
  4031  		case 1:
  4032  			return s.entryNewValue1(ssa.OpArrayMake1, t, s.zeroVal(t.Elem()))
  4033  		}
  4034  	}
  4035  	s.Fatalf("zero for type %v not implemented", t)
  4036  	return nil
  4037  }
  4038  
  4039  type callKind int8
  4040  
  4041  const (
  4042  	callNormal callKind = iota
  4043  	callDefer
  4044  	callDeferStack
  4045  	callGo
  4046  	callTail
  4047  )
  4048  
  4049  type sfRtCallDef struct {
  4050  	rtfn  *obj.LSym
  4051  	rtype types.Kind
  4052  }
  4053  
  4054  var softFloatOps map[ssa.Op]sfRtCallDef
  4055  
  4056  func softfloatInit() {
  4057  	// Some of these operations get transformed by sfcall.
  4058  	softFloatOps = map[ssa.Op]sfRtCallDef{
  4059  		ssa.OpAdd32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4060  		ssa.OpAdd64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4061  		ssa.OpSub32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4062  		ssa.OpSub64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4063  		ssa.OpMul32F: {typecheck.LookupRuntimeFunc("fmul32"), types.TFLOAT32},
  4064  		ssa.OpMul64F: {typecheck.LookupRuntimeFunc("fmul64"), types.TFLOAT64},
  4065  		ssa.OpDiv32F: {typecheck.LookupRuntimeFunc("fdiv32"), types.TFLOAT32},
  4066  		ssa.OpDiv64F: {typecheck.LookupRuntimeFunc("fdiv64"), types.TFLOAT64},
  4067  
  4068  		ssa.OpEq64F:   {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4069  		ssa.OpEq32F:   {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4070  		ssa.OpNeq64F:  {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4071  		ssa.OpNeq32F:  {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4072  		ssa.OpLess64F: {typecheck.LookupRuntimeFunc("fgt64"), types.TBOOL},
  4073  		ssa.OpLess32F: {typecheck.LookupRuntimeFunc("fgt32"), types.TBOOL},
  4074  		ssa.OpLeq64F:  {typecheck.LookupRuntimeFunc("fge64"), types.TBOOL},
  4075  		ssa.OpLeq32F:  {typecheck.LookupRuntimeFunc("fge32"), types.TBOOL},
  4076  
  4077  		ssa.OpCvt32to32F:  {typecheck.LookupRuntimeFunc("fint32to32"), types.TFLOAT32},
  4078  		ssa.OpCvt32Fto32:  {typecheck.LookupRuntimeFunc("f32toint32"), types.TINT32},
  4079  		ssa.OpCvt64to32F:  {typecheck.LookupRuntimeFunc("fint64to32"), types.TFLOAT32},
  4080  		ssa.OpCvt32Fto64:  {typecheck.LookupRuntimeFunc("f32toint64"), types.TINT64},
  4081  		ssa.OpCvt64Uto32F: {typecheck.LookupRuntimeFunc("fuint64to32"), types.TFLOAT32},
  4082  		ssa.OpCvt32Fto64U: {typecheck.LookupRuntimeFunc("f32touint64"), types.TUINT64},
  4083  		ssa.OpCvt32to64F:  {typecheck.LookupRuntimeFunc("fint32to64"), types.TFLOAT64},
  4084  		ssa.OpCvt64Fto32:  {typecheck.LookupRuntimeFunc("f64toint32"), types.TINT32},
  4085  		ssa.OpCvt64to64F:  {typecheck.LookupRuntimeFunc("fint64to64"), types.TFLOAT64},
  4086  		ssa.OpCvt64Fto64:  {typecheck.LookupRuntimeFunc("f64toint64"), types.TINT64},
  4087  		ssa.OpCvt64Uto64F: {typecheck.LookupRuntimeFunc("fuint64to64"), types.TFLOAT64},
  4088  		ssa.OpCvt64Fto64U: {typecheck.LookupRuntimeFunc("f64touint64"), types.TUINT64},
  4089  		ssa.OpCvt32Fto64F: {typecheck.LookupRuntimeFunc("f32to64"), types.TFLOAT64},
  4090  		ssa.OpCvt64Fto32F: {typecheck.LookupRuntimeFunc("f64to32"), types.TFLOAT32},
  4091  	}
  4092  }
  4093  
  4094  // TODO: do not emit sfcall if operation can be optimized to constant in later
  4095  // opt phase
  4096  func (s *state) sfcall(op ssa.Op, args ...*ssa.Value) (*ssa.Value, bool) {
  4097  	f2i := func(t *types.Type) *types.Type {
  4098  		switch t.Kind() {
  4099  		case types.TFLOAT32:
  4100  			return types.Types[types.TUINT32]
  4101  		case types.TFLOAT64:
  4102  			return types.Types[types.TUINT64]
  4103  		}
  4104  		return t
  4105  	}
  4106  
  4107  	if callDef, ok := softFloatOps[op]; ok {
  4108  		switch op {
  4109  		case ssa.OpLess32F,
  4110  			ssa.OpLess64F,
  4111  			ssa.OpLeq32F,
  4112  			ssa.OpLeq64F:
  4113  			args[0], args[1] = args[1], args[0]
  4114  		case ssa.OpSub32F,
  4115  			ssa.OpSub64F:
  4116  			args[1] = s.newValue1(s.ssaOp(ir.ONEG, types.Types[callDef.rtype]), args[1].Type, args[1])
  4117  		}
  4118  
  4119  		// runtime functions take uints for floats and returns uints.
  4120  		// Convert to uints so we use the right calling convention.
  4121  		for i, a := range args {
  4122  			if a.Type.IsFloat() {
  4123  				args[i] = s.newValue1(ssa.OpCopy, f2i(a.Type), a)
  4124  			}
  4125  		}
  4126  
  4127  		rt := types.Types[callDef.rtype]
  4128  		result := s.rtcall(callDef.rtfn, true, []*types.Type{f2i(rt)}, args...)[0]
  4129  		if rt.IsFloat() {
  4130  			result = s.newValue1(ssa.OpCopy, rt, result)
  4131  		}
  4132  		if op == ssa.OpNeq32F || op == ssa.OpNeq64F {
  4133  			result = s.newValue1(ssa.OpNot, result.Type, result)
  4134  		}
  4135  		return result, true
  4136  	}
  4137  	return nil, false
  4138  }
  4139  
  4140  var intrinsics map[intrinsicKey]intrinsicBuilder
  4141  
  4142  // An intrinsicBuilder converts a call node n into an ssa value that
  4143  // implements that call as an intrinsic. args is a list of arguments to the func.
  4144  type intrinsicBuilder func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value
  4145  
  4146  type intrinsicKey struct {
  4147  	arch *sys.Arch
  4148  	pkg  string
  4149  	fn   string
  4150  }
  4151  
  4152  func InitTables() {
  4153  	intrinsics = map[intrinsicKey]intrinsicBuilder{}
  4154  
  4155  	var all []*sys.Arch
  4156  	var p4 []*sys.Arch
  4157  	var p8 []*sys.Arch
  4158  	var lwatomics []*sys.Arch
  4159  	for _, a := range &sys.Archs {
  4160  		all = append(all, a)
  4161  		if a.PtrSize == 4 {
  4162  			p4 = append(p4, a)
  4163  		} else {
  4164  			p8 = append(p8, a)
  4165  		}
  4166  		if a.Family != sys.PPC64 {
  4167  			lwatomics = append(lwatomics, a)
  4168  		}
  4169  	}
  4170  
  4171  	// add adds the intrinsic b for pkg.fn for the given list of architectures.
  4172  	add := func(pkg, fn string, b intrinsicBuilder, archs ...*sys.Arch) {
  4173  		for _, a := range archs {
  4174  			intrinsics[intrinsicKey{a, pkg, fn}] = b
  4175  		}
  4176  	}
  4177  	// addF does the same as add but operates on architecture families.
  4178  	addF := func(pkg, fn string, b intrinsicBuilder, archFamilies ...sys.ArchFamily) {
  4179  		m := 0
  4180  		for _, f := range archFamilies {
  4181  			if f >= 32 {
  4182  				panic("too many architecture families")
  4183  			}
  4184  			m |= 1 << uint(f)
  4185  		}
  4186  		for _, a := range all {
  4187  			if m>>uint(a.Family)&1 != 0 {
  4188  				intrinsics[intrinsicKey{a, pkg, fn}] = b
  4189  			}
  4190  		}
  4191  	}
  4192  	// alias defines pkg.fn = pkg2.fn2 for all architectures in archs for which pkg2.fn2 exists.
  4193  	alias := func(pkg, fn, pkg2, fn2 string, archs ...*sys.Arch) {
  4194  		aliased := false
  4195  		for _, a := range archs {
  4196  			if b, ok := intrinsics[intrinsicKey{a, pkg2, fn2}]; ok {
  4197  				intrinsics[intrinsicKey{a, pkg, fn}] = b
  4198  				aliased = true
  4199  			}
  4200  		}
  4201  		if !aliased {
  4202  			panic(fmt.Sprintf("attempted to alias undefined intrinsic: %s.%s", pkg, fn))
  4203  		}
  4204  	}
  4205  
  4206  	/******** runtime ********/
  4207  	if !base.Flag.Cfg.Instrumenting {
  4208  		add("runtime", "slicebytetostringtmp",
  4209  			func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4210  				// Compiler frontend optimizations emit OBYTES2STRTMP nodes
  4211  				// for the backend instead of slicebytetostringtmp calls
  4212  				// when not instrumenting.
  4213  				return s.newValue2(ssa.OpStringMake, n.Type(), args[0], args[1])
  4214  			},
  4215  			all...)
  4216  	}
  4217  	addF("runtime/internal/math", "MulUintptr",
  4218  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4219  			if s.config.PtrSize == 4 {
  4220  				return s.newValue2(ssa.OpMul32uover, types.NewTuple(types.Types[types.TUINT], types.Types[types.TUINT]), args[0], args[1])
  4221  			}
  4222  			return s.newValue2(ssa.OpMul64uover, types.NewTuple(types.Types[types.TUINT], types.Types[types.TUINT]), args[0], args[1])
  4223  		},
  4224  		sys.AMD64, sys.I386, sys.Loong64, sys.MIPS64, sys.RISCV64, sys.ARM64)
  4225  	add("runtime", "KeepAlive",
  4226  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4227  			data := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, args[0])
  4228  			s.vars[memVar] = s.newValue2(ssa.OpKeepAlive, types.TypeMem, data, s.mem())
  4229  			return nil
  4230  		},
  4231  		all...)
  4232  	add("runtime", "getclosureptr",
  4233  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4234  			return s.newValue0(ssa.OpGetClosurePtr, s.f.Config.Types.Uintptr)
  4235  		},
  4236  		all...)
  4237  
  4238  	add("runtime", "getcallerpc",
  4239  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4240  			return s.newValue0(ssa.OpGetCallerPC, s.f.Config.Types.Uintptr)
  4241  		},
  4242  		all...)
  4243  
  4244  	add("runtime", "getcallersp",
  4245  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4246  			return s.newValue1(ssa.OpGetCallerSP, s.f.Config.Types.Uintptr, s.mem())
  4247  		},
  4248  		all...)
  4249  
  4250  	addF("runtime", "publicationBarrier",
  4251  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4252  			s.vars[memVar] = s.newValue1(ssa.OpPubBarrier, types.TypeMem, s.mem())
  4253  			return nil
  4254  		},
  4255  		sys.ARM64, sys.PPC64, sys.RISCV64)
  4256  
  4257  	brev_arch := []sys.ArchFamily{sys.AMD64, sys.I386, sys.ARM64, sys.ARM, sys.S390X}
  4258  	if buildcfg.GOPPC64 >= 10 {
  4259  		// Use only on Power10 as the new byte reverse instructions that Power10 provide
  4260  		// make it worthwhile as an intrinsic
  4261  		brev_arch = append(brev_arch, sys.PPC64)
  4262  	}
  4263  	/******** runtime/internal/sys ********/
  4264  	addF("runtime/internal/sys", "Bswap32",
  4265  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4266  			return s.newValue1(ssa.OpBswap32, types.Types[types.TUINT32], args[0])
  4267  		},
  4268  		brev_arch...)
  4269  	addF("runtime/internal/sys", "Bswap64",
  4270  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4271  			return s.newValue1(ssa.OpBswap64, types.Types[types.TUINT64], args[0])
  4272  		},
  4273  		brev_arch...)
  4274  
  4275  	/****** Prefetch ******/
  4276  	makePrefetchFunc := func(op ssa.Op) func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4277  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4278  			s.vars[memVar] = s.newValue2(op, types.TypeMem, args[0], s.mem())
  4279  			return nil
  4280  		}
  4281  	}
  4282  
  4283  	// Make Prefetch intrinsics for supported platforms
  4284  	// On the unsupported platforms stub function will be eliminated
  4285  	addF("runtime/internal/sys", "Prefetch", makePrefetchFunc(ssa.OpPrefetchCache),
  4286  		sys.AMD64, sys.ARM64, sys.PPC64)
  4287  	addF("runtime/internal/sys", "PrefetchStreamed", makePrefetchFunc(ssa.OpPrefetchCacheStreamed),
  4288  		sys.AMD64, sys.ARM64, sys.PPC64)
  4289  
  4290  	/******** runtime/internal/atomic ********/
  4291  	addF("runtime/internal/atomic", "Load",
  4292  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4293  			v := s.newValue2(ssa.OpAtomicLoad32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], s.mem())
  4294  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4295  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  4296  		},
  4297  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4298  	addF("runtime/internal/atomic", "Load8",
  4299  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4300  			v := s.newValue2(ssa.OpAtomicLoad8, types.NewTuple(types.Types[types.TUINT8], types.TypeMem), args[0], s.mem())
  4301  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4302  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT8], v)
  4303  		},
  4304  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4305  	addF("runtime/internal/atomic", "Load64",
  4306  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4307  			v := s.newValue2(ssa.OpAtomicLoad64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], s.mem())
  4308  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4309  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  4310  		},
  4311  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4312  	addF("runtime/internal/atomic", "LoadAcq",
  4313  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4314  			v := s.newValue2(ssa.OpAtomicLoadAcq32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], s.mem())
  4315  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4316  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  4317  		},
  4318  		sys.PPC64, sys.S390X)
  4319  	addF("runtime/internal/atomic", "LoadAcq64",
  4320  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4321  			v := s.newValue2(ssa.OpAtomicLoadAcq64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], s.mem())
  4322  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4323  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  4324  		},
  4325  		sys.PPC64)
  4326  	addF("runtime/internal/atomic", "Loadp",
  4327  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4328  			v := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(s.f.Config.Types.BytePtr, types.TypeMem), args[0], s.mem())
  4329  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4330  			return s.newValue1(ssa.OpSelect0, s.f.Config.Types.BytePtr, v)
  4331  		},
  4332  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4333  
  4334  	addF("runtime/internal/atomic", "Store",
  4335  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4336  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStore32, types.TypeMem, args[0], args[1], s.mem())
  4337  			return nil
  4338  		},
  4339  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4340  	addF("runtime/internal/atomic", "Store8",
  4341  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4342  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStore8, types.TypeMem, args[0], args[1], s.mem())
  4343  			return nil
  4344  		},
  4345  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4346  	addF("runtime/internal/atomic", "Store64",
  4347  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4348  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStore64, types.TypeMem, args[0], args[1], s.mem())
  4349  			return nil
  4350  		},
  4351  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4352  	addF("runtime/internal/atomic", "StorepNoWB",
  4353  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4354  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStorePtrNoWB, types.TypeMem, args[0], args[1], s.mem())
  4355  			return nil
  4356  		},
  4357  		sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.RISCV64, sys.S390X)
  4358  	addF("runtime/internal/atomic", "StoreRel",
  4359  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4360  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStoreRel32, types.TypeMem, args[0], args[1], s.mem())
  4361  			return nil
  4362  		},
  4363  		sys.PPC64, sys.S390X)
  4364  	addF("runtime/internal/atomic", "StoreRel64",
  4365  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4366  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStoreRel64, types.TypeMem, args[0], args[1], s.mem())
  4367  			return nil
  4368  		},
  4369  		sys.PPC64)
  4370  
  4371  	addF("runtime/internal/atomic", "Xchg",
  4372  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4373  			v := s.newValue3(ssa.OpAtomicExchange32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], args[1], s.mem())
  4374  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4375  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  4376  		},
  4377  		sys.AMD64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4378  	addF("runtime/internal/atomic", "Xchg64",
  4379  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4380  			v := s.newValue3(ssa.OpAtomicExchange64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], args[1], s.mem())
  4381  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4382  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  4383  		},
  4384  		sys.AMD64, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4385  
  4386  	type atomicOpEmitter func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind)
  4387  
  4388  	makeAtomicGuardedIntrinsicARM64 := func(op0, op1 ssa.Op, typ, rtyp types.Kind, emit atomicOpEmitter) intrinsicBuilder {
  4389  
  4390  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4391  			// Target Atomic feature is identified by dynamic detection
  4392  			addr := s.entryNewValue1A(ssa.OpAddr, types.Types[types.TBOOL].PtrTo(), ir.Syms.ARM64HasATOMICS, s.sb)
  4393  			v := s.load(types.Types[types.TBOOL], addr)
  4394  			b := s.endBlock()
  4395  			b.Kind = ssa.BlockIf
  4396  			b.SetControl(v)
  4397  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4398  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4399  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4400  			b.AddEdgeTo(bTrue)
  4401  			b.AddEdgeTo(bFalse)
  4402  			b.Likely = ssa.BranchLikely
  4403  
  4404  			// We have atomic instructions - use it directly.
  4405  			s.startBlock(bTrue)
  4406  			emit(s, n, args, op1, typ)
  4407  			s.endBlock().AddEdgeTo(bEnd)
  4408  
  4409  			// Use original instruction sequence.
  4410  			s.startBlock(bFalse)
  4411  			emit(s, n, args, op0, typ)
  4412  			s.endBlock().AddEdgeTo(bEnd)
  4413  
  4414  			// Merge results.
  4415  			s.startBlock(bEnd)
  4416  			if rtyp == types.TNIL {
  4417  				return nil
  4418  			} else {
  4419  				return s.variable(n, types.Types[rtyp])
  4420  			}
  4421  		}
  4422  	}
  4423  
  4424  	atomicXchgXaddEmitterARM64 := func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind) {
  4425  		v := s.newValue3(op, types.NewTuple(types.Types[typ], types.TypeMem), args[0], args[1], s.mem())
  4426  		s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4427  		s.vars[n] = s.newValue1(ssa.OpSelect0, types.Types[typ], v)
  4428  	}
  4429  	addF("runtime/internal/atomic", "Xchg",
  4430  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicExchange32, ssa.OpAtomicExchange32Variant, types.TUINT32, types.TUINT32, atomicXchgXaddEmitterARM64),
  4431  		sys.ARM64)
  4432  	addF("runtime/internal/atomic", "Xchg64",
  4433  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicExchange64, ssa.OpAtomicExchange64Variant, types.TUINT64, types.TUINT64, atomicXchgXaddEmitterARM64),
  4434  		sys.ARM64)
  4435  
  4436  	addF("runtime/internal/atomic", "Xadd",
  4437  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4438  			v := s.newValue3(ssa.OpAtomicAdd32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], args[1], s.mem())
  4439  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4440  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  4441  		},
  4442  		sys.AMD64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4443  	addF("runtime/internal/atomic", "Xadd64",
  4444  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4445  			v := s.newValue3(ssa.OpAtomicAdd64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], args[1], s.mem())
  4446  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4447  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  4448  		},
  4449  		sys.AMD64, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4450  
  4451  	addF("runtime/internal/atomic", "Xadd",
  4452  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAdd32, ssa.OpAtomicAdd32Variant, types.TUINT32, types.TUINT32, atomicXchgXaddEmitterARM64),
  4453  		sys.ARM64)
  4454  	addF("runtime/internal/atomic", "Xadd64",
  4455  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAdd64, ssa.OpAtomicAdd64Variant, types.TUINT64, types.TUINT64, atomicXchgXaddEmitterARM64),
  4456  		sys.ARM64)
  4457  
  4458  	addF("runtime/internal/atomic", "Cas",
  4459  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4460  			v := s.newValue4(ssa.OpAtomicCompareAndSwap32, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4461  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4462  			return s.newValue1(ssa.OpSelect0, types.Types[types.TBOOL], v)
  4463  		},
  4464  		sys.AMD64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4465  	addF("runtime/internal/atomic", "Cas64",
  4466  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4467  			v := s.newValue4(ssa.OpAtomicCompareAndSwap64, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4468  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4469  			return s.newValue1(ssa.OpSelect0, types.Types[types.TBOOL], v)
  4470  		},
  4471  		sys.AMD64, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4472  	addF("runtime/internal/atomic", "CasRel",
  4473  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4474  			v := s.newValue4(ssa.OpAtomicCompareAndSwap32, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4475  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4476  			return s.newValue1(ssa.OpSelect0, types.Types[types.TBOOL], v)
  4477  		},
  4478  		sys.PPC64)
  4479  
  4480  	atomicCasEmitterARM64 := func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind) {
  4481  		v := s.newValue4(op, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4482  		s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4483  		s.vars[n] = s.newValue1(ssa.OpSelect0, types.Types[typ], v)
  4484  	}
  4485  
  4486  	addF("runtime/internal/atomic", "Cas",
  4487  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicCompareAndSwap32, ssa.OpAtomicCompareAndSwap32Variant, types.TUINT32, types.TBOOL, atomicCasEmitterARM64),
  4488  		sys.ARM64)
  4489  	addF("runtime/internal/atomic", "Cas64",
  4490  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicCompareAndSwap64, ssa.OpAtomicCompareAndSwap64Variant, types.TUINT64, types.TBOOL, atomicCasEmitterARM64),
  4491  		sys.ARM64)
  4492  
  4493  	addF("runtime/internal/atomic", "And8",
  4494  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4495  			s.vars[memVar] = s.newValue3(ssa.OpAtomicAnd8, types.TypeMem, args[0], args[1], s.mem())
  4496  			return nil
  4497  		},
  4498  		sys.AMD64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4499  	addF("runtime/internal/atomic", "And",
  4500  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4501  			s.vars[memVar] = s.newValue3(ssa.OpAtomicAnd32, types.TypeMem, args[0], args[1], s.mem())
  4502  			return nil
  4503  		},
  4504  		sys.AMD64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4505  	addF("runtime/internal/atomic", "Or8",
  4506  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4507  			s.vars[memVar] = s.newValue3(ssa.OpAtomicOr8, types.TypeMem, args[0], args[1], s.mem())
  4508  			return nil
  4509  		},
  4510  		sys.AMD64, sys.ARM64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4511  	addF("runtime/internal/atomic", "Or",
  4512  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4513  			s.vars[memVar] = s.newValue3(ssa.OpAtomicOr32, types.TypeMem, args[0], args[1], s.mem())
  4514  			return nil
  4515  		},
  4516  		sys.AMD64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4517  
  4518  	atomicAndOrEmitterARM64 := func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind) {
  4519  		s.vars[memVar] = s.newValue3(op, types.TypeMem, args[0], args[1], s.mem())
  4520  	}
  4521  
  4522  	addF("runtime/internal/atomic", "And8",
  4523  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAnd8, ssa.OpAtomicAnd8Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4524  		sys.ARM64)
  4525  	addF("runtime/internal/atomic", "And",
  4526  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAnd32, ssa.OpAtomicAnd32Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4527  		sys.ARM64)
  4528  	addF("runtime/internal/atomic", "Or8",
  4529  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicOr8, ssa.OpAtomicOr8Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4530  		sys.ARM64)
  4531  	addF("runtime/internal/atomic", "Or",
  4532  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicOr32, ssa.OpAtomicOr32Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4533  		sys.ARM64)
  4534  
  4535  	// Aliases for atomic load operations
  4536  	alias("runtime/internal/atomic", "Loadint32", "runtime/internal/atomic", "Load", all...)
  4537  	alias("runtime/internal/atomic", "Loadint64", "runtime/internal/atomic", "Load64", all...)
  4538  	alias("runtime/internal/atomic", "Loaduintptr", "runtime/internal/atomic", "Load", p4...)
  4539  	alias("runtime/internal/atomic", "Loaduintptr", "runtime/internal/atomic", "Load64", p8...)
  4540  	alias("runtime/internal/atomic", "Loaduint", "runtime/internal/atomic", "Load", p4...)
  4541  	alias("runtime/internal/atomic", "Loaduint", "runtime/internal/atomic", "Load64", p8...)
  4542  	alias("runtime/internal/atomic", "LoadAcq", "runtime/internal/atomic", "Load", lwatomics...)
  4543  	alias("runtime/internal/atomic", "LoadAcq64", "runtime/internal/atomic", "Load64", lwatomics...)
  4544  	alias("runtime/internal/atomic", "LoadAcquintptr", "runtime/internal/atomic", "LoadAcq", p4...)
  4545  	alias("sync", "runtime_LoadAcquintptr", "runtime/internal/atomic", "LoadAcq", p4...) // linknamed
  4546  	alias("runtime/internal/atomic", "LoadAcquintptr", "runtime/internal/atomic", "LoadAcq64", p8...)
  4547  	alias("sync", "runtime_LoadAcquintptr", "runtime/internal/atomic", "LoadAcq64", p8...) // linknamed
  4548  
  4549  	// Aliases for atomic store operations
  4550  	alias("runtime/internal/atomic", "Storeint32", "runtime/internal/atomic", "Store", all...)
  4551  	alias("runtime/internal/atomic", "Storeint64", "runtime/internal/atomic", "Store64", all...)
  4552  	alias("runtime/internal/atomic", "Storeuintptr", "runtime/internal/atomic", "Store", p4...)
  4553  	alias("runtime/internal/atomic", "Storeuintptr", "runtime/internal/atomic", "Store64", p8...)
  4554  	alias("runtime/internal/atomic", "StoreRel", "runtime/internal/atomic", "Store", lwatomics...)
  4555  	alias("runtime/internal/atomic", "StoreRel64", "runtime/internal/atomic", "Store64", lwatomics...)
  4556  	alias("runtime/internal/atomic", "StoreReluintptr", "runtime/internal/atomic", "StoreRel", p4...)
  4557  	alias("sync", "runtime_StoreReluintptr", "runtime/internal/atomic", "StoreRel", p4...) // linknamed
  4558  	alias("runtime/internal/atomic", "StoreReluintptr", "runtime/internal/atomic", "StoreRel64", p8...)
  4559  	alias("sync", "runtime_StoreReluintptr", "runtime/internal/atomic", "StoreRel64", p8...) // linknamed
  4560  
  4561  	// Aliases for atomic swap operations
  4562  	alias("runtime/internal/atomic", "Xchgint32", "runtime/internal/atomic", "Xchg", all...)
  4563  	alias("runtime/internal/atomic", "Xchgint64", "runtime/internal/atomic", "Xchg64", all...)
  4564  	alias("runtime/internal/atomic", "Xchguintptr", "runtime/internal/atomic", "Xchg", p4...)
  4565  	alias("runtime/internal/atomic", "Xchguintptr", "runtime/internal/atomic", "Xchg64", p8...)
  4566  
  4567  	// Aliases for atomic add operations
  4568  	alias("runtime/internal/atomic", "Xaddint32", "runtime/internal/atomic", "Xadd", all...)
  4569  	alias("runtime/internal/atomic", "Xaddint64", "runtime/internal/atomic", "Xadd64", all...)
  4570  	alias("runtime/internal/atomic", "Xadduintptr", "runtime/internal/atomic", "Xadd", p4...)
  4571  	alias("runtime/internal/atomic", "Xadduintptr", "runtime/internal/atomic", "Xadd64", p8...)
  4572  
  4573  	// Aliases for atomic CAS operations
  4574  	alias("runtime/internal/atomic", "Casint32", "runtime/internal/atomic", "Cas", all...)
  4575  	alias("runtime/internal/atomic", "Casint64", "runtime/internal/atomic", "Cas64", all...)
  4576  	alias("runtime/internal/atomic", "Casuintptr", "runtime/internal/atomic", "Cas", p4...)
  4577  	alias("runtime/internal/atomic", "Casuintptr", "runtime/internal/atomic", "Cas64", p8...)
  4578  	alias("runtime/internal/atomic", "Casp1", "runtime/internal/atomic", "Cas", p4...)
  4579  	alias("runtime/internal/atomic", "Casp1", "runtime/internal/atomic", "Cas64", p8...)
  4580  	alias("runtime/internal/atomic", "CasRel", "runtime/internal/atomic", "Cas", lwatomics...)
  4581  
  4582  	/******** math ********/
  4583  	addF("math", "sqrt",
  4584  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4585  			return s.newValue1(ssa.OpSqrt, types.Types[types.TFLOAT64], args[0])
  4586  		},
  4587  		sys.I386, sys.AMD64, sys.ARM, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm)
  4588  	addF("math", "Trunc",
  4589  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4590  			return s.newValue1(ssa.OpTrunc, types.Types[types.TFLOAT64], args[0])
  4591  		},
  4592  		sys.ARM64, sys.PPC64, sys.S390X, sys.Wasm)
  4593  	addF("math", "Ceil",
  4594  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4595  			return s.newValue1(ssa.OpCeil, types.Types[types.TFLOAT64], args[0])
  4596  		},
  4597  		sys.ARM64, sys.PPC64, sys.S390X, sys.Wasm)
  4598  	addF("math", "Floor",
  4599  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4600  			return s.newValue1(ssa.OpFloor, types.Types[types.TFLOAT64], args[0])
  4601  		},
  4602  		sys.ARM64, sys.PPC64, sys.S390X, sys.Wasm)
  4603  	addF("math", "Round",
  4604  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4605  			return s.newValue1(ssa.OpRound, types.Types[types.TFLOAT64], args[0])
  4606  		},
  4607  		sys.ARM64, sys.PPC64, sys.S390X)
  4608  	addF("math", "RoundToEven",
  4609  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4610  			return s.newValue1(ssa.OpRoundToEven, types.Types[types.TFLOAT64], args[0])
  4611  		},
  4612  		sys.ARM64, sys.S390X, sys.Wasm)
  4613  	addF("math", "Abs",
  4614  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4615  			return s.newValue1(ssa.OpAbs, types.Types[types.TFLOAT64], args[0])
  4616  		},
  4617  		sys.ARM64, sys.ARM, sys.PPC64, sys.RISCV64, sys.Wasm, sys.MIPS, sys.MIPS64)
  4618  	addF("math", "Copysign",
  4619  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4620  			return s.newValue2(ssa.OpCopysign, types.Types[types.TFLOAT64], args[0], args[1])
  4621  		},
  4622  		sys.PPC64, sys.RISCV64, sys.Wasm)
  4623  	addF("math", "FMA",
  4624  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4625  			return s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4626  		},
  4627  		sys.ARM64, sys.PPC64, sys.RISCV64, sys.S390X)
  4628  	addF("math", "FMA",
  4629  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4630  			if !s.config.UseFMA {
  4631  				s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4632  				return s.variable(n, types.Types[types.TFLOAT64])
  4633  			}
  4634  
  4635  			if buildcfg.GOAMD64 >= 3 {
  4636  				return s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4637  			}
  4638  
  4639  			v := s.entryNewValue0A(ssa.OpHasCPUFeature, types.Types[types.TBOOL], ir.Syms.X86HasFMA)
  4640  			b := s.endBlock()
  4641  			b.Kind = ssa.BlockIf
  4642  			b.SetControl(v)
  4643  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4644  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4645  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4646  			b.AddEdgeTo(bTrue)
  4647  			b.AddEdgeTo(bFalse)
  4648  			b.Likely = ssa.BranchLikely // >= haswell cpus are common
  4649  
  4650  			// We have the intrinsic - use it directly.
  4651  			s.startBlock(bTrue)
  4652  			s.vars[n] = s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4653  			s.endBlock().AddEdgeTo(bEnd)
  4654  
  4655  			// Call the pure Go version.
  4656  			s.startBlock(bFalse)
  4657  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4658  			s.endBlock().AddEdgeTo(bEnd)
  4659  
  4660  			// Merge results.
  4661  			s.startBlock(bEnd)
  4662  			return s.variable(n, types.Types[types.TFLOAT64])
  4663  		},
  4664  		sys.AMD64)
  4665  	addF("math", "FMA",
  4666  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4667  			if !s.config.UseFMA {
  4668  				s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4669  				return s.variable(n, types.Types[types.TFLOAT64])
  4670  			}
  4671  			addr := s.entryNewValue1A(ssa.OpAddr, types.Types[types.TBOOL].PtrTo(), ir.Syms.ARMHasVFPv4, s.sb)
  4672  			v := s.load(types.Types[types.TBOOL], addr)
  4673  			b := s.endBlock()
  4674  			b.Kind = ssa.BlockIf
  4675  			b.SetControl(v)
  4676  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4677  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4678  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4679  			b.AddEdgeTo(bTrue)
  4680  			b.AddEdgeTo(bFalse)
  4681  			b.Likely = ssa.BranchLikely
  4682  
  4683  			// We have the intrinsic - use it directly.
  4684  			s.startBlock(bTrue)
  4685  			s.vars[n] = s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4686  			s.endBlock().AddEdgeTo(bEnd)
  4687  
  4688  			// Call the pure Go version.
  4689  			s.startBlock(bFalse)
  4690  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4691  			s.endBlock().AddEdgeTo(bEnd)
  4692  
  4693  			// Merge results.
  4694  			s.startBlock(bEnd)
  4695  			return s.variable(n, types.Types[types.TFLOAT64])
  4696  		},
  4697  		sys.ARM)
  4698  
  4699  	makeRoundAMD64 := func(op ssa.Op) func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4700  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4701  			if buildcfg.GOAMD64 >= 2 {
  4702  				return s.newValue1(op, types.Types[types.TFLOAT64], args[0])
  4703  			}
  4704  
  4705  			v := s.entryNewValue0A(ssa.OpHasCPUFeature, types.Types[types.TBOOL], ir.Syms.X86HasSSE41)
  4706  			b := s.endBlock()
  4707  			b.Kind = ssa.BlockIf
  4708  			b.SetControl(v)
  4709  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4710  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4711  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4712  			b.AddEdgeTo(bTrue)
  4713  			b.AddEdgeTo(bFalse)
  4714  			b.Likely = ssa.BranchLikely // most machines have sse4.1 nowadays
  4715  
  4716  			// We have the intrinsic - use it directly.
  4717  			s.startBlock(bTrue)
  4718  			s.vars[n] = s.newValue1(op, types.Types[types.TFLOAT64], args[0])
  4719  			s.endBlock().AddEdgeTo(bEnd)
  4720  
  4721  			// Call the pure Go version.
  4722  			s.startBlock(bFalse)
  4723  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4724  			s.endBlock().AddEdgeTo(bEnd)
  4725  
  4726  			// Merge results.
  4727  			s.startBlock(bEnd)
  4728  			return s.variable(n, types.Types[types.TFLOAT64])
  4729  		}
  4730  	}
  4731  	addF("math", "RoundToEven",
  4732  		makeRoundAMD64(ssa.OpRoundToEven),
  4733  		sys.AMD64)
  4734  	addF("math", "Floor",
  4735  		makeRoundAMD64(ssa.OpFloor),
  4736  		sys.AMD64)
  4737  	addF("math", "Ceil",
  4738  		makeRoundAMD64(ssa.OpCeil),
  4739  		sys.AMD64)
  4740  	addF("math", "Trunc",
  4741  		makeRoundAMD64(ssa.OpTrunc),
  4742  		sys.AMD64)
  4743  
  4744  	/******** math/bits ********/
  4745  	addF("math/bits", "TrailingZeros64",
  4746  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4747  			return s.newValue1(ssa.OpCtz64, types.Types[types.TINT], args[0])
  4748  		},
  4749  		sys.AMD64, sys.I386, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4750  	addF("math/bits", "TrailingZeros32",
  4751  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4752  			return s.newValue1(ssa.OpCtz32, types.Types[types.TINT], args[0])
  4753  		},
  4754  		sys.AMD64, sys.I386, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4755  	addF("math/bits", "TrailingZeros16",
  4756  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4757  			x := s.newValue1(ssa.OpZeroExt16to32, types.Types[types.TUINT32], args[0])
  4758  			c := s.constInt32(types.Types[types.TUINT32], 1<<16)
  4759  			y := s.newValue2(ssa.OpOr32, types.Types[types.TUINT32], x, c)
  4760  			return s.newValue1(ssa.OpCtz32, types.Types[types.TINT], y)
  4761  		},
  4762  		sys.MIPS)
  4763  	addF("math/bits", "TrailingZeros16",
  4764  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4765  			return s.newValue1(ssa.OpCtz16, types.Types[types.TINT], args[0])
  4766  		},
  4767  		sys.AMD64, sys.I386, sys.ARM, sys.ARM64, sys.Wasm)
  4768  	addF("math/bits", "TrailingZeros16",
  4769  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4770  			x := s.newValue1(ssa.OpZeroExt16to64, types.Types[types.TUINT64], args[0])
  4771  			c := s.constInt64(types.Types[types.TUINT64], 1<<16)
  4772  			y := s.newValue2(ssa.OpOr64, types.Types[types.TUINT64], x, c)
  4773  			return s.newValue1(ssa.OpCtz64, types.Types[types.TINT], y)
  4774  		},
  4775  		sys.S390X, sys.PPC64)
  4776  	addF("math/bits", "TrailingZeros8",
  4777  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4778  			x := s.newValue1(ssa.OpZeroExt8to32, types.Types[types.TUINT32], args[0])
  4779  			c := s.constInt32(types.Types[types.TUINT32], 1<<8)
  4780  			y := s.newValue2(ssa.OpOr32, types.Types[types.TUINT32], x, c)
  4781  			return s.newValue1(ssa.OpCtz32, types.Types[types.TINT], y)
  4782  		},
  4783  		sys.MIPS)
  4784  	addF("math/bits", "TrailingZeros8",
  4785  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4786  			return s.newValue1(ssa.OpCtz8, types.Types[types.TINT], args[0])
  4787  		},
  4788  		sys.AMD64, sys.I386, sys.ARM, sys.ARM64, sys.Wasm)
  4789  	addF("math/bits", "TrailingZeros8",
  4790  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4791  			x := s.newValue1(ssa.OpZeroExt8to64, types.Types[types.TUINT64], args[0])
  4792  			c := s.constInt64(types.Types[types.TUINT64], 1<<8)
  4793  			y := s.newValue2(ssa.OpOr64, types.Types[types.TUINT64], x, c)
  4794  			return s.newValue1(ssa.OpCtz64, types.Types[types.TINT], y)
  4795  		},
  4796  		sys.S390X)
  4797  	alias("math/bits", "ReverseBytes64", "runtime/internal/sys", "Bswap64", all...)
  4798  	alias("math/bits", "ReverseBytes32", "runtime/internal/sys", "Bswap32", all...)
  4799  	// ReverseBytes inlines correctly, no need to intrinsify it.
  4800  	// Nothing special is needed for targets where ReverseBytes16 lowers to a rotate
  4801  	// On Power10, 16-bit rotate is not available so use BRH instruction
  4802  	if buildcfg.GOPPC64 >= 10 {
  4803  		addF("math/bits", "ReverseBytes16",
  4804  			func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4805  				return s.newValue1(ssa.OpBswap16, types.Types[types.TUINT], args[0])
  4806  			},
  4807  			sys.PPC64)
  4808  	}
  4809  
  4810  	addF("math/bits", "Len64",
  4811  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4812  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], args[0])
  4813  		},
  4814  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4815  	addF("math/bits", "Len32",
  4816  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4817  			return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], args[0])
  4818  		},
  4819  		sys.AMD64, sys.ARM64, sys.PPC64)
  4820  	addF("math/bits", "Len32",
  4821  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4822  			if s.config.PtrSize == 4 {
  4823  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], args[0])
  4824  			}
  4825  			x := s.newValue1(ssa.OpZeroExt32to64, types.Types[types.TUINT64], args[0])
  4826  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], x)
  4827  		},
  4828  		sys.ARM, sys.S390X, sys.MIPS, sys.Wasm)
  4829  	addF("math/bits", "Len16",
  4830  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4831  			if s.config.PtrSize == 4 {
  4832  				x := s.newValue1(ssa.OpZeroExt16to32, types.Types[types.TUINT32], args[0])
  4833  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], x)
  4834  			}
  4835  			x := s.newValue1(ssa.OpZeroExt16to64, types.Types[types.TUINT64], args[0])
  4836  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], x)
  4837  		},
  4838  		sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4839  	addF("math/bits", "Len16",
  4840  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4841  			return s.newValue1(ssa.OpBitLen16, types.Types[types.TINT], args[0])
  4842  		},
  4843  		sys.AMD64)
  4844  	addF("math/bits", "Len8",
  4845  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4846  			if s.config.PtrSize == 4 {
  4847  				x := s.newValue1(ssa.OpZeroExt8to32, types.Types[types.TUINT32], args[0])
  4848  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], x)
  4849  			}
  4850  			x := s.newValue1(ssa.OpZeroExt8to64, types.Types[types.TUINT64], args[0])
  4851  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], x)
  4852  		},
  4853  		sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4854  	addF("math/bits", "Len8",
  4855  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4856  			return s.newValue1(ssa.OpBitLen8, types.Types[types.TINT], args[0])
  4857  		},
  4858  		sys.AMD64)
  4859  	addF("math/bits", "Len",
  4860  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4861  			if s.config.PtrSize == 4 {
  4862  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], args[0])
  4863  			}
  4864  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], args[0])
  4865  		},
  4866  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4867  	// LeadingZeros is handled because it trivially calls Len.
  4868  	addF("math/bits", "Reverse64",
  4869  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4870  			return s.newValue1(ssa.OpBitRev64, types.Types[types.TINT], args[0])
  4871  		},
  4872  		sys.ARM64)
  4873  	addF("math/bits", "Reverse32",
  4874  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4875  			return s.newValue1(ssa.OpBitRev32, types.Types[types.TINT], args[0])
  4876  		},
  4877  		sys.ARM64)
  4878  	addF("math/bits", "Reverse16",
  4879  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4880  			return s.newValue1(ssa.OpBitRev16, types.Types[types.TINT], args[0])
  4881  		},
  4882  		sys.ARM64)
  4883  	addF("math/bits", "Reverse8",
  4884  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4885  			return s.newValue1(ssa.OpBitRev8, types.Types[types.TINT], args[0])
  4886  		},
  4887  		sys.ARM64)
  4888  	addF("math/bits", "Reverse",
  4889  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4890  			return s.newValue1(ssa.OpBitRev64, types.Types[types.TINT], args[0])
  4891  		},
  4892  		sys.ARM64)
  4893  	addF("math/bits", "RotateLeft8",
  4894  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4895  			return s.newValue2(ssa.OpRotateLeft8, types.Types[types.TUINT8], args[0], args[1])
  4896  		},
  4897  		sys.AMD64)
  4898  	addF("math/bits", "RotateLeft16",
  4899  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4900  			return s.newValue2(ssa.OpRotateLeft16, types.Types[types.TUINT16], args[0], args[1])
  4901  		},
  4902  		sys.AMD64)
  4903  	addF("math/bits", "RotateLeft32",
  4904  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4905  			return s.newValue2(ssa.OpRotateLeft32, types.Types[types.TUINT32], args[0], args[1])
  4906  		},
  4907  		sys.AMD64, sys.ARM, sys.ARM64, sys.S390X, sys.PPC64, sys.Wasm, sys.Loong64)
  4908  	addF("math/bits", "RotateLeft64",
  4909  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4910  			return s.newValue2(ssa.OpRotateLeft64, types.Types[types.TUINT64], args[0], args[1])
  4911  		},
  4912  		sys.AMD64, sys.ARM64, sys.S390X, sys.PPC64, sys.Wasm, sys.Loong64)
  4913  	alias("math/bits", "RotateLeft", "math/bits", "RotateLeft64", p8...)
  4914  
  4915  	makeOnesCountAMD64 := func(op ssa.Op) func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4916  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4917  			if buildcfg.GOAMD64 >= 2 {
  4918  				return s.newValue1(op, types.Types[types.TINT], args[0])
  4919  			}
  4920  
  4921  			v := s.entryNewValue0A(ssa.OpHasCPUFeature, types.Types[types.TBOOL], ir.Syms.X86HasPOPCNT)
  4922  			b := s.endBlock()
  4923  			b.Kind = ssa.BlockIf
  4924  			b.SetControl(v)
  4925  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4926  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4927  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4928  			b.AddEdgeTo(bTrue)
  4929  			b.AddEdgeTo(bFalse)
  4930  			b.Likely = ssa.BranchLikely // most machines have popcnt nowadays
  4931  
  4932  			// We have the intrinsic - use it directly.
  4933  			s.startBlock(bTrue)
  4934  			s.vars[n] = s.newValue1(op, types.Types[types.TINT], args[0])
  4935  			s.endBlock().AddEdgeTo(bEnd)
  4936  
  4937  			// Call the pure Go version.
  4938  			s.startBlock(bFalse)
  4939  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TINT]
  4940  			s.endBlock().AddEdgeTo(bEnd)
  4941  
  4942  			// Merge results.
  4943  			s.startBlock(bEnd)
  4944  			return s.variable(n, types.Types[types.TINT])
  4945  		}
  4946  	}
  4947  	addF("math/bits", "OnesCount64",
  4948  		makeOnesCountAMD64(ssa.OpPopCount64),
  4949  		sys.AMD64)
  4950  	addF("math/bits", "OnesCount64",
  4951  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4952  			return s.newValue1(ssa.OpPopCount64, types.Types[types.TINT], args[0])
  4953  		},
  4954  		sys.PPC64, sys.ARM64, sys.S390X, sys.Wasm)
  4955  	addF("math/bits", "OnesCount32",
  4956  		makeOnesCountAMD64(ssa.OpPopCount32),
  4957  		sys.AMD64)
  4958  	addF("math/bits", "OnesCount32",
  4959  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4960  			return s.newValue1(ssa.OpPopCount32, types.Types[types.TINT], args[0])
  4961  		},
  4962  		sys.PPC64, sys.ARM64, sys.S390X, sys.Wasm)
  4963  	addF("math/bits", "OnesCount16",
  4964  		makeOnesCountAMD64(ssa.OpPopCount16),
  4965  		sys.AMD64)
  4966  	addF("math/bits", "OnesCount16",
  4967  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4968  			return s.newValue1(ssa.OpPopCount16, types.Types[types.TINT], args[0])
  4969  		},
  4970  		sys.ARM64, sys.S390X, sys.PPC64, sys.Wasm)
  4971  	addF("math/bits", "OnesCount8",
  4972  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4973  			return s.newValue1(ssa.OpPopCount8, types.Types[types.TINT], args[0])
  4974  		},
  4975  		sys.S390X, sys.PPC64, sys.Wasm)
  4976  	addF("math/bits", "OnesCount",
  4977  		makeOnesCountAMD64(ssa.OpPopCount64),
  4978  		sys.AMD64)
  4979  	addF("math/bits", "Mul64",
  4980  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4981  			return s.newValue2(ssa.OpMul64uhilo, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1])
  4982  		},
  4983  		sys.AMD64, sys.ARM64, sys.PPC64, sys.S390X, sys.MIPS64, sys.RISCV64, sys.Loong64)
  4984  	alias("math/bits", "Mul", "math/bits", "Mul64", p8...)
  4985  	alias("runtime/internal/math", "Mul64", "math/bits", "Mul64", p8...)
  4986  	addF("math/bits", "Add64",
  4987  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4988  			return s.newValue3(ssa.OpAdd64carry, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1], args[2])
  4989  		},
  4990  		sys.AMD64, sys.ARM64, sys.PPC64, sys.S390X, sys.RISCV64, sys.Loong64, sys.MIPS64)
  4991  	alias("math/bits", "Add", "math/bits", "Add64", p8...)
  4992  	alias("runtime/internal/math", "Add64", "math/bits", "Add64", all...)
  4993  	addF("math/bits", "Sub64",
  4994  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4995  			return s.newValue3(ssa.OpSub64borrow, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1], args[2])
  4996  		},
  4997  		sys.AMD64, sys.ARM64, sys.PPC64, sys.S390X, sys.RISCV64, sys.Loong64, sys.MIPS64)
  4998  	alias("math/bits", "Sub", "math/bits", "Sub64", p8...)
  4999  	addF("math/bits", "Div64",
  5000  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  5001  			// check for divide-by-zero/overflow and panic with appropriate message
  5002  			cmpZero := s.newValue2(s.ssaOp(ir.ONE, types.Types[types.TUINT64]), types.Types[types.TBOOL], args[2], s.zeroVal(types.Types[types.TUINT64]))
  5003  			s.check(cmpZero, ir.Syms.Panicdivide)
  5004  			cmpOverflow := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT64]), types.Types[types.TBOOL], args[0], args[2])
  5005  			s.check(cmpOverflow, ir.Syms.Panicoverflow)
  5006  			return s.newValue3(ssa.OpDiv128u, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1], args[2])
  5007  		},
  5008  		sys.AMD64)
  5009  	alias("math/bits", "Div", "math/bits", "Div64", sys.ArchAMD64)
  5010  
  5011  	alias("runtime/internal/sys", "TrailingZeros8", "math/bits", "TrailingZeros8", all...)
  5012  	alias("runtime/internal/sys", "TrailingZeros32", "math/bits", "TrailingZeros32", all...)
  5013  	alias("runtime/internal/sys", "TrailingZeros64", "math/bits", "TrailingZeros64", all...)
  5014  	alias("runtime/internal/sys", "Len8", "math/bits", "Len8", all...)
  5015  	alias("runtime/internal/sys", "Len64", "math/bits", "Len64", all...)
  5016  	alias("runtime/internal/sys", "OnesCount64", "math/bits", "OnesCount64", all...)
  5017  
  5018  	/******** sync/atomic ********/
  5019  
  5020  	// Note: these are disabled by flag_race in findIntrinsic below.
  5021  	alias("sync/atomic", "LoadInt32", "runtime/internal/atomic", "Load", all...)
  5022  	alias("sync/atomic", "LoadInt64", "runtime/internal/atomic", "Load64", all...)
  5023  	alias("sync/atomic", "LoadPointer", "runtime/internal/atomic", "Loadp", all...)
  5024  	alias("sync/atomic", "LoadUint32", "runtime/internal/atomic", "Load", all...)
  5025  	alias("sync/atomic", "LoadUint64", "runtime/internal/atomic", "Load64", all...)
  5026  	alias("sync/atomic", "LoadUintptr", "runtime/internal/atomic", "Load", p4...)
  5027  	alias("sync/atomic", "LoadUintptr", "runtime/internal/atomic", "Load64", p8...)
  5028  
  5029  	alias("sync/atomic", "StoreInt32", "runtime/internal/atomic", "Store", all...)
  5030  	alias("sync/atomic", "StoreInt64", "runtime/internal/atomic", "Store64", all...)
  5031  	// Note: not StorePointer, that needs a write barrier.  Same below for {CompareAnd}Swap.
  5032  	alias("sync/atomic", "StoreUint32", "runtime/internal/atomic", "Store", all...)
  5033  	alias("sync/atomic", "StoreUint64", "runtime/internal/atomic", "Store64", all...)
  5034  	alias("sync/atomic", "StoreUintptr", "runtime/internal/atomic", "Store", p4...)
  5035  	alias("sync/atomic", "StoreUintptr", "runtime/internal/atomic", "Store64", p8...)
  5036  
  5037  	alias("sync/atomic", "SwapInt32", "runtime/internal/atomic", "Xchg", all...)
  5038  	alias("sync/atomic", "SwapInt64", "runtime/internal/atomic", "Xchg64", all...)
  5039  	alias("sync/atomic", "SwapUint32", "runtime/internal/atomic", "Xchg", all...)
  5040  	alias("sync/atomic", "SwapUint64", "runtime/internal/atomic", "Xchg64", all...)
  5041  	alias("sync/atomic", "SwapUintptr", "runtime/internal/atomic", "Xchg", p4...)
  5042  	alias("sync/atomic", "SwapUintptr", "runtime/internal/atomic", "Xchg64", p8...)
  5043  
  5044  	alias("sync/atomic", "CompareAndSwapInt32", "runtime/internal/atomic", "Cas", all...)
  5045  	alias("sync/atomic", "CompareAndSwapInt64", "runtime/internal/atomic", "Cas64", all...)
  5046  	alias("sync/atomic", "CompareAndSwapUint32", "runtime/internal/atomic", "Cas", all...)
  5047  	alias("sync/atomic", "CompareAndSwapUint64", "runtime/internal/atomic", "Cas64", all...)
  5048  	alias("sync/atomic", "CompareAndSwapUintptr", "runtime/internal/atomic", "Cas", p4...)
  5049  	alias("sync/atomic", "CompareAndSwapUintptr", "runtime/internal/atomic", "Cas64", p8...)
  5050  
  5051  	alias("sync/atomic", "AddInt32", "runtime/internal/atomic", "Xadd", all...)
  5052  	alias("sync/atomic", "AddInt64", "runtime/internal/atomic", "Xadd64", all...)
  5053  	alias("sync/atomic", "AddUint32", "runtime/internal/atomic", "Xadd", all...)
  5054  	alias("sync/atomic", "AddUint64", "runtime/internal/atomic", "Xadd64", all...)
  5055  	alias("sync/atomic", "AddUintptr", "runtime/internal/atomic", "Xadd", p4...)
  5056  	alias("sync/atomic", "AddUintptr", "runtime/internal/atomic", "Xadd64", p8...)
  5057  
  5058  	/******** math/big ********/
  5059  	alias("math/big", "mulWW", "math/bits", "Mul64", p8...)
  5060  }
  5061  
  5062  // findIntrinsic returns a function which builds the SSA equivalent of the
  5063  // function identified by the symbol sym.  If sym is not an intrinsic call, returns nil.
  5064  func findIntrinsic(sym *types.Sym) intrinsicBuilder {
  5065  	if sym == nil || sym.Pkg == nil {
  5066  		return nil
  5067  	}
  5068  	pkg := sym.Pkg.Path
  5069  	if sym.Pkg == ir.Pkgs.Runtime {
  5070  		pkg = "runtime"
  5071  	}
  5072  	if base.Flag.Race && pkg == "sync/atomic" {
  5073  		// The race detector needs to be able to intercept these calls.
  5074  		// We can't intrinsify them.
  5075  		return nil
  5076  	}
  5077  	// Skip intrinsifying math functions (which may contain hard-float
  5078  	// instructions) when soft-float
  5079  	if Arch.SoftFloat && pkg == "math" {
  5080  		return nil
  5081  	}
  5082  
  5083  	fn := sym.Name
  5084  	if ssa.IntrinsicsDisable {
  5085  		if pkg == "runtime" && (fn == "getcallerpc" || fn == "getcallersp" || fn == "getclosureptr") {
  5086  			// These runtime functions don't have definitions, must be intrinsics.
  5087  		} else {
  5088  			return nil
  5089  		}
  5090  	}
  5091  	return intrinsics[intrinsicKey{Arch.LinkArch.Arch, pkg, fn}]
  5092  }
  5093  
  5094  func IsIntrinsicCall(n *ir.CallExpr) bool {
  5095  	if n == nil {
  5096  		return false
  5097  	}
  5098  	name, ok := n.Fun.(*ir.Name)
  5099  	if !ok {
  5100  		return false
  5101  	}
  5102  	return findIntrinsic(name.Sym()) != nil
  5103  }
  5104  
  5105  // intrinsicCall converts a call to a recognized intrinsic function into the intrinsic SSA operation.
  5106  func (s *state) intrinsicCall(n *ir.CallExpr) *ssa.Value {
  5107  	v := findIntrinsic(n.Fun.Sym())(s, n, s.intrinsicArgs(n))
  5108  	if ssa.IntrinsicsDebug > 0 {
  5109  		x := v
  5110  		if x == nil {
  5111  			x = s.mem()
  5112  		}
  5113  		if x.Op == ssa.OpSelect0 || x.Op == ssa.OpSelect1 {
  5114  			x = x.Args[0]
  5115  		}
  5116  		base.WarnfAt(n.Pos(), "intrinsic substitution for %v with %s", n.Fun.Sym().Name, x.LongString())
  5117  	}
  5118  	return v
  5119  }
  5120  
  5121  // intrinsicArgs extracts args from n, evaluates them to SSA values, and returns them.
  5122  func (s *state) intrinsicArgs(n *ir.CallExpr) []*ssa.Value {
  5123  	args := make([]*ssa.Value, len(n.Args))
  5124  	for i, n := range n.Args {
  5125  		args[i] = s.expr(n)
  5126  	}
  5127  	return args
  5128  }
  5129  
  5130  // openDeferRecord adds code to evaluate and store the function for an open-code defer
  5131  // call, and records info about the defer, so we can generate proper code on the
  5132  // exit paths. n is the sub-node of the defer node that is the actual function
  5133  // call. We will also record funcdata information on where the function is stored
  5134  // (as well as the deferBits variable), and this will enable us to run the proper
  5135  // defer calls during panics.
  5136  func (s *state) openDeferRecord(n *ir.CallExpr) {
  5137  	if len(n.Args) != 0 || n.Op() != ir.OCALLFUNC || n.Fun.Type().NumResults() != 0 {
  5138  		s.Fatalf("defer call with arguments or results: %v", n)
  5139  	}
  5140  
  5141  	opendefer := &openDeferInfo{
  5142  		n: n,
  5143  	}
  5144  	fn := n.Fun
  5145  	// We must always store the function value in a stack slot for the
  5146  	// runtime panic code to use. But in the defer exit code, we will
  5147  	// call the function directly if it is a static function.
  5148  	closureVal := s.expr(fn)
  5149  	closure := s.openDeferSave(fn.Type(), closureVal)
  5150  	opendefer.closureNode = closure.Aux.(*ir.Name)
  5151  	if !(fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC) {
  5152  		opendefer.closure = closure
  5153  	}
  5154  	index := len(s.openDefers)
  5155  	s.openDefers = append(s.openDefers, opendefer)
  5156  
  5157  	// Update deferBits only after evaluation and storage to stack of
  5158  	// the function is successful.
  5159  	bitvalue := s.constInt8(types.Types[types.TUINT8], 1<<uint(index))
  5160  	newDeferBits := s.newValue2(ssa.OpOr8, types.Types[types.TUINT8], s.variable(deferBitsVar, types.Types[types.TUINT8]), bitvalue)
  5161  	s.vars[deferBitsVar] = newDeferBits
  5162  	s.store(types.Types[types.TUINT8], s.deferBitsAddr, newDeferBits)
  5163  }
  5164  
  5165  // openDeferSave generates SSA nodes to store a value (with type t) for an
  5166  // open-coded defer at an explicit autotmp location on the stack, so it can be
  5167  // reloaded and used for the appropriate call on exit. Type t must be a function type
  5168  // (therefore SSAable). val is the value to be stored. The function returns an SSA
  5169  // value representing a pointer to the autotmp location.
  5170  func (s *state) openDeferSave(t *types.Type, val *ssa.Value) *ssa.Value {
  5171  	if !ssa.CanSSA(t) {
  5172  		s.Fatalf("openDeferSave of non-SSA-able type %v val=%v", t, val)
  5173  	}
  5174  	if !t.HasPointers() {
  5175  		s.Fatalf("openDeferSave of pointerless type %v val=%v", t, val)
  5176  	}
  5177  	pos := val.Pos
  5178  	temp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
  5179  	temp.SetOpenDeferSlot(true)
  5180  	temp.SetFrameOffset(int64(len(s.openDefers))) // so cmpstackvarlt can order them
  5181  	var addrTemp *ssa.Value
  5182  	// Use OpVarLive to make sure stack slot for the closure is not removed by
  5183  	// dead-store elimination
  5184  	if s.curBlock.ID != s.f.Entry.ID {
  5185  		// Force the tmp storing this defer function to be declared in the entry
  5186  		// block, so that it will be live for the defer exit code (which will
  5187  		// actually access it only if the associated defer call has been activated).
  5188  		if t.HasPointers() {
  5189  			s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  5190  		}
  5191  		s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  5192  		addrTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.defvars[s.f.Entry.ID][memVar])
  5193  	} else {
  5194  		// Special case if we're still in the entry block. We can't use
  5195  		// the above code, since s.defvars[s.f.Entry.ID] isn't defined
  5196  		// until we end the entry block with s.endBlock().
  5197  		if t.HasPointers() {
  5198  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, temp, s.mem(), false)
  5199  		}
  5200  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, temp, s.mem(), false)
  5201  		addrTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.mem(), false)
  5202  	}
  5203  	// Since we may use this temp during exit depending on the
  5204  	// deferBits, we must define it unconditionally on entry.
  5205  	// Therefore, we must make sure it is zeroed out in the entry
  5206  	// block if it contains pointers, else GC may wrongly follow an
  5207  	// uninitialized pointer value.
  5208  	temp.SetNeedzero(true)
  5209  	// We are storing to the stack, hence we can avoid the full checks in
  5210  	// storeType() (no write barrier) and do a simple store().
  5211  	s.store(t, addrTemp, val)
  5212  	return addrTemp
  5213  }
  5214  
  5215  // openDeferExit generates SSA for processing all the open coded defers at exit.
  5216  // The code involves loading deferBits, and checking each of the bits to see if
  5217  // the corresponding defer statement was executed. For each bit that is turned
  5218  // on, the associated defer call is made.
  5219  func (s *state) openDeferExit() {
  5220  	deferExit := s.f.NewBlock(ssa.BlockPlain)
  5221  	s.endBlock().AddEdgeTo(deferExit)
  5222  	s.startBlock(deferExit)
  5223  	s.lastDeferExit = deferExit
  5224  	s.lastDeferCount = len(s.openDefers)
  5225  	zeroval := s.constInt8(types.Types[types.TUINT8], 0)
  5226  	// Test for and run defers in reverse order
  5227  	for i := len(s.openDefers) - 1; i >= 0; i-- {
  5228  		r := s.openDefers[i]
  5229  		bCond := s.f.NewBlock(ssa.BlockPlain)
  5230  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  5231  
  5232  		deferBits := s.variable(deferBitsVar, types.Types[types.TUINT8])
  5233  		// Generate code to check if the bit associated with the current
  5234  		// defer is set.
  5235  		bitval := s.constInt8(types.Types[types.TUINT8], 1<<uint(i))
  5236  		andval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, bitval)
  5237  		eqVal := s.newValue2(ssa.OpEq8, types.Types[types.TBOOL], andval, zeroval)
  5238  		b := s.endBlock()
  5239  		b.Kind = ssa.BlockIf
  5240  		b.SetControl(eqVal)
  5241  		b.AddEdgeTo(bEnd)
  5242  		b.AddEdgeTo(bCond)
  5243  		bCond.AddEdgeTo(bEnd)
  5244  		s.startBlock(bCond)
  5245  
  5246  		// Clear this bit in deferBits and force store back to stack, so
  5247  		// we will not try to re-run this defer call if this defer call panics.
  5248  		nbitval := s.newValue1(ssa.OpCom8, types.Types[types.TUINT8], bitval)
  5249  		maskedval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, nbitval)
  5250  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, maskedval)
  5251  		// Use this value for following tests, so we keep previous
  5252  		// bits cleared.
  5253  		s.vars[deferBitsVar] = maskedval
  5254  
  5255  		// Generate code to call the function call of the defer, using the
  5256  		// closure that were stored in argtmps at the point of the defer
  5257  		// statement.
  5258  		fn := r.n.Fun
  5259  		stksize := fn.Type().ArgWidth()
  5260  		var callArgs []*ssa.Value
  5261  		var call *ssa.Value
  5262  		if r.closure != nil {
  5263  			v := s.load(r.closure.Type.Elem(), r.closure)
  5264  			s.maybeNilCheckClosure(v, callDefer)
  5265  			codeptr := s.rawLoad(types.Types[types.TUINTPTR], v)
  5266  			aux := ssa.ClosureAuxCall(s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  5267  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, v)
  5268  		} else {
  5269  			aux := ssa.StaticAuxCall(fn.(*ir.Name).Linksym(), s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  5270  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5271  		}
  5272  		callArgs = append(callArgs, s.mem())
  5273  		call.AddArgs(callArgs...)
  5274  		call.AuxInt = stksize
  5275  		s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, 0, call)
  5276  		// Make sure that the stack slots with pointers are kept live
  5277  		// through the call (which is a pre-emption point). Also, we will
  5278  		// use the first call of the last defer exit to compute liveness
  5279  		// for the deferreturn, so we want all stack slots to be live.
  5280  		if r.closureNode != nil {
  5281  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.closureNode, s.mem(), false)
  5282  		}
  5283  
  5284  		s.endBlock()
  5285  		s.startBlock(bEnd)
  5286  	}
  5287  }
  5288  
  5289  func (s *state) callResult(n *ir.CallExpr, k callKind) *ssa.Value {
  5290  	return s.call(n, k, false, nil)
  5291  }
  5292  
  5293  func (s *state) callAddr(n *ir.CallExpr, k callKind) *ssa.Value {
  5294  	return s.call(n, k, true, nil)
  5295  }
  5296  
  5297  // Calls the function n using the specified call type.
  5298  // Returns the address of the return value (or nil if none).
  5299  func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool, deferExtra ir.Expr) *ssa.Value {
  5300  	s.prevCall = nil
  5301  	var calleeLSym *obj.LSym // target function (if static)
  5302  	var closure *ssa.Value   // ptr to closure to run (if dynamic)
  5303  	var codeptr *ssa.Value   // ptr to target code (if dynamic)
  5304  	var dextra *ssa.Value    // defer extra arg
  5305  	var rcvr *ssa.Value      // receiver to set
  5306  	fn := n.Fun
  5307  	var ACArgs []*types.Type    // AuxCall args
  5308  	var ACResults []*types.Type // AuxCall results
  5309  	var callArgs []*ssa.Value   // For late-expansion, the args themselves (not stored, args to the call instead).
  5310  
  5311  	callABI := s.f.ABIDefault
  5312  
  5313  	if k != callNormal && k != callTail && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.Fun.Type().NumResults() != 0) {
  5314  		s.Fatalf("go/defer call with arguments: %v", n)
  5315  	}
  5316  
  5317  	switch n.Op() {
  5318  	case ir.OCALLFUNC:
  5319  		if (k == callNormal || k == callTail) && fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC {
  5320  			fn := fn.(*ir.Name)
  5321  			calleeLSym = callTargetLSym(fn)
  5322  			if buildcfg.Experiment.RegabiArgs {
  5323  				// This is a static call, so it may be
  5324  				// a direct call to a non-ABIInternal
  5325  				// function. fn.Func may be nil for
  5326  				// some compiler-generated functions,
  5327  				// but those are all ABIInternal.
  5328  				if fn.Func != nil {
  5329  					callABI = abiForFunc(fn.Func, s.f.ABI0, s.f.ABI1)
  5330  				}
  5331  			} else {
  5332  				// TODO(register args) remove after register abi is working
  5333  				inRegistersImported := fn.Pragma()&ir.RegisterParams != 0
  5334  				inRegistersSamePackage := fn.Func != nil && fn.Func.Pragma&ir.RegisterParams != 0
  5335  				if inRegistersImported || inRegistersSamePackage {
  5336  					callABI = s.f.ABI1
  5337  				}
  5338  			}
  5339  			break
  5340  		}
  5341  		closure = s.expr(fn)
  5342  		if k != callDefer && k != callDeferStack {
  5343  			// Deferred nil function needs to panic when the function is invoked,
  5344  			// not the point of defer statement.
  5345  			s.maybeNilCheckClosure(closure, k)
  5346  		}
  5347  	case ir.OCALLINTER:
  5348  		if fn.Op() != ir.ODOTINTER {
  5349  			s.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
  5350  		}
  5351  		fn := fn.(*ir.SelectorExpr)
  5352  		var iclosure *ssa.Value
  5353  		iclosure, rcvr = s.getClosureAndRcvr(fn)
  5354  		if k == callNormal {
  5355  			codeptr = s.load(types.Types[types.TUINTPTR], iclosure)
  5356  		} else {
  5357  			closure = iclosure
  5358  		}
  5359  	}
  5360  	if deferExtra != nil {
  5361  		dextra = s.expr(deferExtra)
  5362  	}
  5363  
  5364  	params := callABI.ABIAnalyze(n.Fun.Type(), false /* Do not set (register) nNames from caller side -- can cause races. */)
  5365  	types.CalcSize(fn.Type())
  5366  	stksize := params.ArgWidth() // includes receiver, args, and results
  5367  
  5368  	res := n.Fun.Type().Results()
  5369  	if k == callNormal || k == callTail {
  5370  		for _, p := range params.OutParams() {
  5371  			ACResults = append(ACResults, p.Type)
  5372  		}
  5373  	}
  5374  
  5375  	var call *ssa.Value
  5376  	if k == callDeferStack {
  5377  		if stksize != 0 {
  5378  			s.Fatalf("deferprocStack with non-zero stack size %d: %v", stksize, n)
  5379  		}
  5380  		// Make a defer struct on the stack.
  5381  		t := deferstruct()
  5382  		_, addr := s.temp(n.Pos(), t)
  5383  		s.store(closure.Type,
  5384  			s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(deferStructFnField), addr),
  5385  			closure)
  5386  
  5387  		// Call runtime.deferprocStack with pointer to _defer record.
  5388  		ACArgs = append(ACArgs, types.Types[types.TUINTPTR])
  5389  		aux := ssa.StaticAuxCall(ir.Syms.DeferprocStack, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5390  		callArgs = append(callArgs, addr, s.mem())
  5391  		call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5392  		call.AddArgs(callArgs...)
  5393  		call.AuxInt = int64(types.PtrSize) // deferprocStack takes a *_defer arg
  5394  	} else {
  5395  		// Store arguments to stack, including defer/go arguments and receiver for method calls.
  5396  		// These are written in SP-offset order.
  5397  		argStart := base.Ctxt.Arch.FixedFrameSize
  5398  		// Defer/go args.
  5399  		if k != callNormal && k != callTail {
  5400  			// Write closure (arg to newproc/deferproc).
  5401  			ACArgs = append(ACArgs, types.Types[types.TUINTPTR]) // not argExtra
  5402  			callArgs = append(callArgs, closure)
  5403  			stksize += int64(types.PtrSize)
  5404  			argStart += int64(types.PtrSize)
  5405  			if dextra != nil {
  5406  				// Extra token of type any for deferproc
  5407  				ACArgs = append(ACArgs, types.Types[types.TINTER])
  5408  				callArgs = append(callArgs, dextra)
  5409  				stksize += 2 * int64(types.PtrSize)
  5410  				argStart += 2 * int64(types.PtrSize)
  5411  			}
  5412  		}
  5413  
  5414  		// Set receiver (for interface calls).
  5415  		if rcvr != nil {
  5416  			callArgs = append(callArgs, rcvr)
  5417  		}
  5418  
  5419  		// Write args.
  5420  		t := n.Fun.Type()
  5421  		args := n.Args
  5422  
  5423  		for _, p := range params.InParams() { // includes receiver for interface calls
  5424  			ACArgs = append(ACArgs, p.Type)
  5425  		}
  5426  
  5427  		// Split the entry block if there are open defers, because later calls to
  5428  		// openDeferSave may cause a mismatch between the mem for an OpDereference
  5429  		// and the call site which uses it. See #49282.
  5430  		if s.curBlock.ID == s.f.Entry.ID && s.hasOpenDefers {
  5431  			b := s.endBlock()
  5432  			b.Kind = ssa.BlockPlain
  5433  			curb := s.f.NewBlock(ssa.BlockPlain)
  5434  			b.AddEdgeTo(curb)
  5435  			s.startBlock(curb)
  5436  		}
  5437  
  5438  		for i, n := range args {
  5439  			callArgs = append(callArgs, s.putArg(n, t.Param(i).Type))
  5440  		}
  5441  
  5442  		callArgs = append(callArgs, s.mem())
  5443  
  5444  		// call target
  5445  		switch {
  5446  		case k == callDefer:
  5447  			sym := ir.Syms.Deferproc
  5448  			if dextra != nil {
  5449  				sym = ir.Syms.Deferprocat
  5450  			}
  5451  			aux := ssa.StaticAuxCall(sym, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults)) // TODO paramResultInfo for Deferproc(at)
  5452  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5453  		case k == callGo:
  5454  			aux := ssa.StaticAuxCall(ir.Syms.Newproc, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5455  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux) // TODO paramResultInfo for Newproc
  5456  		case closure != nil:
  5457  			// rawLoad because loading the code pointer from a
  5458  			// closure is always safe, but IsSanitizerSafeAddr
  5459  			// can't always figure that out currently, and it's
  5460  			// critical that we not clobber any arguments already
  5461  			// stored onto the stack.
  5462  			codeptr = s.rawLoad(types.Types[types.TUINTPTR], closure)
  5463  			aux := ssa.ClosureAuxCall(callABI.ABIAnalyzeTypes(ACArgs, ACResults))
  5464  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, closure)
  5465  		case codeptr != nil:
  5466  			// Note that the "receiver" parameter is nil because the actual receiver is the first input parameter.
  5467  			aux := ssa.InterfaceAuxCall(params)
  5468  			call = s.newValue1A(ssa.OpInterLECall, aux.LateExpansionResultType(), aux, codeptr)
  5469  		case calleeLSym != nil:
  5470  			aux := ssa.StaticAuxCall(calleeLSym, params)
  5471  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5472  			if k == callTail {
  5473  				call.Op = ssa.OpTailLECall
  5474  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5475  			}
  5476  		default:
  5477  			s.Fatalf("bad call type %v %v", n.Op(), n)
  5478  		}
  5479  		call.AddArgs(callArgs...)
  5480  		call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
  5481  	}
  5482  	s.prevCall = call
  5483  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(ACResults)), call)
  5484  	// Insert VarLive opcodes.
  5485  	for _, v := range n.KeepAlive {
  5486  		if !v.Addrtaken() {
  5487  			s.Fatalf("KeepAlive variable %v must have Addrtaken set", v)
  5488  		}
  5489  		switch v.Class {
  5490  		case ir.PAUTO, ir.PPARAM, ir.PPARAMOUT:
  5491  		default:
  5492  			s.Fatalf("KeepAlive variable %v must be Auto or Arg", v)
  5493  		}
  5494  		s.vars[memVar] = s.newValue1A(ssa.OpVarLive, types.TypeMem, v, s.mem())
  5495  	}
  5496  
  5497  	// Finish block for defers
  5498  	if k == callDefer || k == callDeferStack {
  5499  		b := s.endBlock()
  5500  		b.Kind = ssa.BlockDefer
  5501  		b.SetControl(call)
  5502  		bNext := s.f.NewBlock(ssa.BlockPlain)
  5503  		b.AddEdgeTo(bNext)
  5504  		// Add recover edge to exit code.
  5505  		r := s.f.NewBlock(ssa.BlockPlain)
  5506  		s.startBlock(r)
  5507  		s.exit()
  5508  		b.AddEdgeTo(r)
  5509  		b.Likely = ssa.BranchLikely
  5510  		s.startBlock(bNext)
  5511  	}
  5512  
  5513  	if len(res) == 0 || k != callNormal {
  5514  		// call has no return value. Continue with the next statement.
  5515  		return nil
  5516  	}
  5517  	fp := res[0]
  5518  	if returnResultAddr {
  5519  		return s.resultAddrOfCall(call, 0, fp.Type)
  5520  	}
  5521  	return s.newValue1I(ssa.OpSelectN, fp.Type, 0, call)
  5522  }
  5523  
  5524  // maybeNilCheckClosure checks if a nil check of a closure is needed in some
  5525  // architecture-dependent situations and, if so, emits the nil check.
  5526  func (s *state) maybeNilCheckClosure(closure *ssa.Value, k callKind) {
  5527  	if Arch.LinkArch.Family == sys.Wasm || buildcfg.GOOS == "aix" && k != callGo {
  5528  		// On AIX, the closure needs to be verified as fn can be nil, except if it's a call go. This needs to be handled by the runtime to have the "go of nil func value" error.
  5529  		// TODO(neelance): On other architectures this should be eliminated by the optimization steps
  5530  		s.nilCheck(closure)
  5531  	}
  5532  }
  5533  
  5534  // getClosureAndRcvr returns values for the appropriate closure and receiver of an
  5535  // interface call
  5536  func (s *state) getClosureAndRcvr(fn *ir.SelectorExpr) (*ssa.Value, *ssa.Value) {
  5537  	i := s.expr(fn.X)
  5538  	itab := s.newValue1(ssa.OpITab, types.Types[types.TUINTPTR], i)
  5539  	s.nilCheck(itab)
  5540  	itabidx := fn.Offset() + 2*int64(types.PtrSize) + 8 // offset of fun field in runtime.itab
  5541  	closure := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.UintptrPtr, itabidx, itab)
  5542  	rcvr := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, i)
  5543  	return closure, rcvr
  5544  }
  5545  
  5546  // etypesign returns the signed-ness of e, for integer/pointer etypes.
  5547  // -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
  5548  func etypesign(e types.Kind) int8 {
  5549  	switch e {
  5550  	case types.TINT8, types.TINT16, types.TINT32, types.TINT64, types.TINT:
  5551  		return -1
  5552  	case types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64, types.TUINT, types.TUINTPTR, types.TUNSAFEPTR:
  5553  		return +1
  5554  	}
  5555  	return 0
  5556  }
  5557  
  5558  // addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
  5559  // The value that the returned Value represents is guaranteed to be non-nil.
  5560  func (s *state) addr(n ir.Node) *ssa.Value {
  5561  	if n.Op() != ir.ONAME {
  5562  		s.pushLine(n.Pos())
  5563  		defer s.popLine()
  5564  	}
  5565  
  5566  	if s.canSSA(n) {
  5567  		s.Fatalf("addr of canSSA expression: %+v", n)
  5568  	}
  5569  
  5570  	t := types.NewPtr(n.Type())
  5571  	linksymOffset := func(lsym *obj.LSym, offset int64) *ssa.Value {
  5572  		v := s.entryNewValue1A(ssa.OpAddr, t, lsym, s.sb)
  5573  		// TODO: Make OpAddr use AuxInt as well as Aux.
  5574  		if offset != 0 {
  5575  			v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
  5576  		}
  5577  		return v
  5578  	}
  5579  	switch n.Op() {
  5580  	case ir.OLINKSYMOFFSET:
  5581  		no := n.(*ir.LinksymOffsetExpr)
  5582  		return linksymOffset(no.Linksym, no.Offset_)
  5583  	case ir.ONAME:
  5584  		n := n.(*ir.Name)
  5585  		if n.Heapaddr != nil {
  5586  			return s.expr(n.Heapaddr)
  5587  		}
  5588  		switch n.Class {
  5589  		case ir.PEXTERN:
  5590  			// global variable
  5591  			return linksymOffset(n.Linksym(), 0)
  5592  		case ir.PPARAM:
  5593  			// parameter slot
  5594  			v := s.decladdrs[n]
  5595  			if v != nil {
  5596  				return v
  5597  			}
  5598  			s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
  5599  			return nil
  5600  		case ir.PAUTO:
  5601  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), !ir.IsAutoTmp(n))
  5602  
  5603  		case ir.PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
  5604  			// ensure that we reuse symbols for out parameters so
  5605  			// that cse works on their addresses
  5606  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), true)
  5607  		default:
  5608  			s.Fatalf("variable address class %v not implemented", n.Class)
  5609  			return nil
  5610  		}
  5611  	case ir.ORESULT:
  5612  		// load return from callee
  5613  		n := n.(*ir.ResultExpr)
  5614  		return s.resultAddrOfCall(s.prevCall, n.Index, n.Type())
  5615  	case ir.OINDEX:
  5616  		n := n.(*ir.IndexExpr)
  5617  		if n.X.Type().IsSlice() {
  5618  			a := s.expr(n.X)
  5619  			i := s.expr(n.Index)
  5620  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], a)
  5621  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5622  			p := s.newValue1(ssa.OpSlicePtr, t, a)
  5623  			return s.newValue2(ssa.OpPtrIndex, t, p, i)
  5624  		} else { // array
  5625  			a := s.addr(n.X)
  5626  			i := s.expr(n.Index)
  5627  			len := s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  5628  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5629  			return s.newValue2(ssa.OpPtrIndex, types.NewPtr(n.X.Type().Elem()), a, i)
  5630  		}
  5631  	case ir.ODEREF:
  5632  		n := n.(*ir.StarExpr)
  5633  		return s.exprPtr(n.X, n.Bounded(), n.Pos())
  5634  	case ir.ODOT:
  5635  		n := n.(*ir.SelectorExpr)
  5636  		p := s.addr(n.X)
  5637  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5638  	case ir.ODOTPTR:
  5639  		n := n.(*ir.SelectorExpr)
  5640  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  5641  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5642  	case ir.OCONVNOP:
  5643  		n := n.(*ir.ConvExpr)
  5644  		if n.Type() == n.X.Type() {
  5645  			return s.addr(n.X)
  5646  		}
  5647  		addr := s.addr(n.X)
  5648  		return s.newValue1(ssa.OpCopy, t, addr) // ensure that addr has the right type
  5649  	case ir.OCALLFUNC, ir.OCALLINTER:
  5650  		n := n.(*ir.CallExpr)
  5651  		return s.callAddr(n, callNormal)
  5652  	case ir.ODOTTYPE, ir.ODYNAMICDOTTYPE:
  5653  		var v *ssa.Value
  5654  		if n.Op() == ir.ODOTTYPE {
  5655  			v, _ = s.dottype(n.(*ir.TypeAssertExpr), false)
  5656  		} else {
  5657  			v, _ = s.dynamicDottype(n.(*ir.DynamicTypeAssertExpr), false)
  5658  		}
  5659  		if v.Op != ssa.OpLoad {
  5660  			s.Fatalf("dottype of non-load")
  5661  		}
  5662  		if v.Args[1] != s.mem() {
  5663  			s.Fatalf("memory no longer live from dottype load")
  5664  		}
  5665  		return v.Args[0]
  5666  	default:
  5667  		s.Fatalf("unhandled addr %v", n.Op())
  5668  		return nil
  5669  	}
  5670  }
  5671  
  5672  // canSSA reports whether n is SSA-able.
  5673  // n must be an ONAME (or an ODOT sequence with an ONAME base).
  5674  func (s *state) canSSA(n ir.Node) bool {
  5675  	if base.Flag.N != 0 {
  5676  		return false
  5677  	}
  5678  	for {
  5679  		nn := n
  5680  		if nn.Op() == ir.ODOT {
  5681  			nn := nn.(*ir.SelectorExpr)
  5682  			n = nn.X
  5683  			continue
  5684  		}
  5685  		if nn.Op() == ir.OINDEX {
  5686  			nn := nn.(*ir.IndexExpr)
  5687  			if nn.X.Type().IsArray() {
  5688  				n = nn.X
  5689  				continue
  5690  			}
  5691  		}
  5692  		break
  5693  	}
  5694  	if n.Op() != ir.ONAME {
  5695  		return false
  5696  	}
  5697  	return s.canSSAName(n.(*ir.Name)) && ssa.CanSSA(n.Type())
  5698  }
  5699  
  5700  func (s *state) canSSAName(name *ir.Name) bool {
  5701  	if name.Addrtaken() || !name.OnStack() {
  5702  		return false
  5703  	}
  5704  	switch name.Class {
  5705  	case ir.PPARAMOUT:
  5706  		if s.hasdefer {
  5707  			// TODO: handle this case? Named return values must be
  5708  			// in memory so that the deferred function can see them.
  5709  			// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
  5710  			// Or maybe not, see issue 18860.  Even unnamed return values
  5711  			// must be written back so if a defer recovers, the caller can see them.
  5712  			return false
  5713  		}
  5714  		if s.cgoUnsafeArgs {
  5715  			// Cgo effectively takes the address of all result args,
  5716  			// but the compiler can't see that.
  5717  			return false
  5718  		}
  5719  	}
  5720  	return true
  5721  	// TODO: try to make more variables SSAable?
  5722  }
  5723  
  5724  // exprPtr evaluates n to a pointer and nil-checks it.
  5725  func (s *state) exprPtr(n ir.Node, bounded bool, lineno src.XPos) *ssa.Value {
  5726  	p := s.expr(n)
  5727  	if bounded || n.NonNil() {
  5728  		if s.f.Frontend().Debug_checknil() && lineno.Line() > 1 {
  5729  			s.f.Warnl(lineno, "removed nil check")
  5730  		}
  5731  		return p
  5732  	}
  5733  	p = s.nilCheck(p)
  5734  	return p
  5735  }
  5736  
  5737  // nilCheck generates nil pointer checking code.
  5738  // Used only for automatically inserted nil checks,
  5739  // not for user code like 'x != nil'.
  5740  // Returns a "definitely not nil" copy of x to ensure proper ordering
  5741  // of the uses of the post-nilcheck pointer.
  5742  func (s *state) nilCheck(ptr *ssa.Value) *ssa.Value {
  5743  	if base.Debug.DisableNil != 0 || s.curfn.NilCheckDisabled() {
  5744  		return ptr
  5745  	}
  5746  	return s.newValue2(ssa.OpNilCheck, ptr.Type, ptr, s.mem())
  5747  }
  5748  
  5749  // boundsCheck generates bounds checking code. Checks if 0 <= idx <[=] len, branches to exit if not.
  5750  // Starts a new block on return.
  5751  // On input, len must be converted to full int width and be nonnegative.
  5752  // Returns idx converted to full int width.
  5753  // If bounded is true then caller guarantees the index is not out of bounds
  5754  // (but boundsCheck will still extend the index to full int width).
  5755  func (s *state) boundsCheck(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  5756  	idx = s.extendIndex(idx, len, kind, bounded)
  5757  
  5758  	if bounded || base.Flag.B != 0 {
  5759  		// If bounded or bounds checking is flag-disabled, then no check necessary,
  5760  		// just return the extended index.
  5761  		//
  5762  		// Here, bounded == true if the compiler generated the index itself,
  5763  		// such as in the expansion of a slice initializer. These indexes are
  5764  		// compiler-generated, not Go program variables, so they cannot be
  5765  		// attacker-controlled, so we can omit Spectre masking as well.
  5766  		//
  5767  		// Note that we do not want to omit Spectre masking in code like:
  5768  		//
  5769  		//	if 0 <= i && i < len(x) {
  5770  		//		use(x[i])
  5771  		//	}
  5772  		//
  5773  		// Lucky for us, bounded==false for that code.
  5774  		// In that case (handled below), we emit a bound check (and Spectre mask)
  5775  		// and then the prove pass will remove the bounds check.
  5776  		// In theory the prove pass could potentially remove certain
  5777  		// Spectre masks, but it's very delicate and probably better
  5778  		// to be conservative and leave them all in.
  5779  		return idx
  5780  	}
  5781  
  5782  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5783  	bPanic := s.f.NewBlock(ssa.BlockExit)
  5784  
  5785  	if !idx.Type.IsSigned() {
  5786  		switch kind {
  5787  		case ssa.BoundsIndex:
  5788  			kind = ssa.BoundsIndexU
  5789  		case ssa.BoundsSliceAlen:
  5790  			kind = ssa.BoundsSliceAlenU
  5791  		case ssa.BoundsSliceAcap:
  5792  			kind = ssa.BoundsSliceAcapU
  5793  		case ssa.BoundsSliceB:
  5794  			kind = ssa.BoundsSliceBU
  5795  		case ssa.BoundsSlice3Alen:
  5796  			kind = ssa.BoundsSlice3AlenU
  5797  		case ssa.BoundsSlice3Acap:
  5798  			kind = ssa.BoundsSlice3AcapU
  5799  		case ssa.BoundsSlice3B:
  5800  			kind = ssa.BoundsSlice3BU
  5801  		case ssa.BoundsSlice3C:
  5802  			kind = ssa.BoundsSlice3CU
  5803  		}
  5804  	}
  5805  
  5806  	var cmp *ssa.Value
  5807  	if kind == ssa.BoundsIndex || kind == ssa.BoundsIndexU {
  5808  		cmp = s.newValue2(ssa.OpIsInBounds, types.Types[types.TBOOL], idx, len)
  5809  	} else {
  5810  		cmp = s.newValue2(ssa.OpIsSliceInBounds, types.Types[types.TBOOL], idx, len)
  5811  	}
  5812  	b := s.endBlock()
  5813  	b.Kind = ssa.BlockIf
  5814  	b.SetControl(cmp)
  5815  	b.Likely = ssa.BranchLikely
  5816  	b.AddEdgeTo(bNext)
  5817  	b.AddEdgeTo(bPanic)
  5818  
  5819  	s.startBlock(bPanic)
  5820  	if Arch.LinkArch.Family == sys.Wasm {
  5821  		// TODO(khr): figure out how to do "register" based calling convention for bounds checks.
  5822  		// Should be similar to gcWriteBarrier, but I can't make it work.
  5823  		s.rtcall(BoundsCheckFunc[kind], false, nil, idx, len)
  5824  	} else {
  5825  		mem := s.newValue3I(ssa.OpPanicBounds, types.TypeMem, int64(kind), idx, len, s.mem())
  5826  		s.endBlock().SetControl(mem)
  5827  	}
  5828  	s.startBlock(bNext)
  5829  
  5830  	// In Spectre index mode, apply an appropriate mask to avoid speculative out-of-bounds accesses.
  5831  	if base.Flag.Cfg.SpectreIndex {
  5832  		op := ssa.OpSpectreIndex
  5833  		if kind != ssa.BoundsIndex && kind != ssa.BoundsIndexU {
  5834  			op = ssa.OpSpectreSliceIndex
  5835  		}
  5836  		idx = s.newValue2(op, types.Types[types.TINT], idx, len)
  5837  	}
  5838  
  5839  	return idx
  5840  }
  5841  
  5842  // If cmp (a bool) is false, panic using the given function.
  5843  func (s *state) check(cmp *ssa.Value, fn *obj.LSym) {
  5844  	b := s.endBlock()
  5845  	b.Kind = ssa.BlockIf
  5846  	b.SetControl(cmp)
  5847  	b.Likely = ssa.BranchLikely
  5848  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5849  	line := s.peekPos()
  5850  	pos := base.Ctxt.PosTable.Pos(line)
  5851  	fl := funcLine{f: fn, base: pos.Base(), line: pos.Line()}
  5852  	bPanic := s.panics[fl]
  5853  	if bPanic == nil {
  5854  		bPanic = s.f.NewBlock(ssa.BlockPlain)
  5855  		s.panics[fl] = bPanic
  5856  		s.startBlock(bPanic)
  5857  		// The panic call takes/returns memory to ensure that the right
  5858  		// memory state is observed if the panic happens.
  5859  		s.rtcall(fn, false, nil)
  5860  	}
  5861  	b.AddEdgeTo(bNext)
  5862  	b.AddEdgeTo(bPanic)
  5863  	s.startBlock(bNext)
  5864  }
  5865  
  5866  func (s *state) intDivide(n ir.Node, a, b *ssa.Value) *ssa.Value {
  5867  	needcheck := true
  5868  	switch b.Op {
  5869  	case ssa.OpConst8, ssa.OpConst16, ssa.OpConst32, ssa.OpConst64:
  5870  		if b.AuxInt != 0 {
  5871  			needcheck = false
  5872  		}
  5873  	}
  5874  	if needcheck {
  5875  		// do a size-appropriate check for zero
  5876  		cmp := s.newValue2(s.ssaOp(ir.ONE, n.Type()), types.Types[types.TBOOL], b, s.zeroVal(n.Type()))
  5877  		s.check(cmp, ir.Syms.Panicdivide)
  5878  	}
  5879  	return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  5880  }
  5881  
  5882  // rtcall issues a call to the given runtime function fn with the listed args.
  5883  // Returns a slice of results of the given result types.
  5884  // The call is added to the end of the current block.
  5885  // If returns is false, the block is marked as an exit block.
  5886  func (s *state) rtcall(fn *obj.LSym, returns bool, results []*types.Type, args ...*ssa.Value) []*ssa.Value {
  5887  	s.prevCall = nil
  5888  	// Write args to the stack
  5889  	off := base.Ctxt.Arch.FixedFrameSize
  5890  	var callArgs []*ssa.Value
  5891  	var callArgTypes []*types.Type
  5892  
  5893  	for _, arg := range args {
  5894  		t := arg.Type
  5895  		off = types.RoundUp(off, t.Alignment())
  5896  		size := t.Size()
  5897  		callArgs = append(callArgs, arg)
  5898  		callArgTypes = append(callArgTypes, t)
  5899  		off += size
  5900  	}
  5901  	off = types.RoundUp(off, int64(types.RegSize))
  5902  
  5903  	// Issue call
  5904  	var call *ssa.Value
  5905  	aux := ssa.StaticAuxCall(fn, s.f.ABIDefault.ABIAnalyzeTypes(callArgTypes, results))
  5906  	callArgs = append(callArgs, s.mem())
  5907  	call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5908  	call.AddArgs(callArgs...)
  5909  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(results)), call)
  5910  
  5911  	if !returns {
  5912  		// Finish block
  5913  		b := s.endBlock()
  5914  		b.Kind = ssa.BlockExit
  5915  		b.SetControl(call)
  5916  		call.AuxInt = off - base.Ctxt.Arch.FixedFrameSize
  5917  		if len(results) > 0 {
  5918  			s.Fatalf("panic call can't have results")
  5919  		}
  5920  		return nil
  5921  	}
  5922  
  5923  	// Load results
  5924  	res := make([]*ssa.Value, len(results))
  5925  	for i, t := range results {
  5926  		off = types.RoundUp(off, t.Alignment())
  5927  		res[i] = s.resultOfCall(call, int64(i), t)
  5928  		off += t.Size()
  5929  	}
  5930  	off = types.RoundUp(off, int64(types.PtrSize))
  5931  
  5932  	// Remember how much callee stack space we needed.
  5933  	call.AuxInt = off
  5934  
  5935  	return res
  5936  }
  5937  
  5938  // do *left = right for type t.
  5939  func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask, leftIsStmt bool) {
  5940  	s.instrument(t, left, instrumentWrite)
  5941  
  5942  	if skip == 0 && (!t.HasPointers() || ssa.IsStackAddr(left)) {
  5943  		// Known to not have write barrier. Store the whole type.
  5944  		s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, left, right, s.mem(), leftIsStmt)
  5945  		return
  5946  	}
  5947  
  5948  	// store scalar fields first, so write barrier stores for
  5949  	// pointer fields can be grouped together, and scalar values
  5950  	// don't need to be live across the write barrier call.
  5951  	// TODO: if the writebarrier pass knows how to reorder stores,
  5952  	// we can do a single store here as long as skip==0.
  5953  	s.storeTypeScalars(t, left, right, skip)
  5954  	if skip&skipPtr == 0 && t.HasPointers() {
  5955  		s.storeTypePtrs(t, left, right)
  5956  	}
  5957  }
  5958  
  5959  // do *left = right for all scalar (non-pointer) parts of t.
  5960  func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip skipMask) {
  5961  	switch {
  5962  	case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex():
  5963  		s.store(t, left, right)
  5964  	case t.IsPtrShaped():
  5965  		if t.IsPtr() && t.Elem().NotInHeap() {
  5966  			s.store(t, left, right) // see issue 42032
  5967  		}
  5968  		// otherwise, no scalar fields.
  5969  	case t.IsString():
  5970  		if skip&skipLen != 0 {
  5971  			return
  5972  		}
  5973  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], right)
  5974  		lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5975  		s.store(types.Types[types.TINT], lenAddr, len)
  5976  	case t.IsSlice():
  5977  		if skip&skipLen == 0 {
  5978  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], right)
  5979  			lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5980  			s.store(types.Types[types.TINT], lenAddr, len)
  5981  		}
  5982  		if skip&skipCap == 0 {
  5983  			cap := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], right)
  5984  			capAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, 2*s.config.PtrSize, left)
  5985  			s.store(types.Types[types.TINT], capAddr, cap)
  5986  		}
  5987  	case t.IsInterface():
  5988  		// itab field doesn't need a write barrier (even though it is a pointer).
  5989  		itab := s.newValue1(ssa.OpITab, s.f.Config.Types.BytePtr, right)
  5990  		s.store(types.Types[types.TUINTPTR], left, itab)
  5991  	case t.IsStruct():
  5992  		n := t.NumFields()
  5993  		for i := 0; i < n; i++ {
  5994  			ft := t.FieldType(i)
  5995  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5996  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5997  			s.storeTypeScalars(ft, addr, val, 0)
  5998  		}
  5999  	case t.IsArray() && t.NumElem() == 0:
  6000  		// nothing
  6001  	case t.IsArray() && t.NumElem() == 1:
  6002  		s.storeTypeScalars(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right), 0)
  6003  	default:
  6004  		s.Fatalf("bad write barrier type %v", t)
  6005  	}
  6006  }
  6007  
  6008  // do *left = right for all pointer parts of t.
  6009  func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) {
  6010  	switch {
  6011  	case t.IsPtrShaped():
  6012  		if t.IsPtr() && t.Elem().NotInHeap() {
  6013  			break // see issue 42032
  6014  		}
  6015  		s.store(t, left, right)
  6016  	case t.IsString():
  6017  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, right)
  6018  		s.store(s.f.Config.Types.BytePtr, left, ptr)
  6019  	case t.IsSlice():
  6020  		elType := types.NewPtr(t.Elem())
  6021  		ptr := s.newValue1(ssa.OpSlicePtr, elType, right)
  6022  		s.store(elType, left, ptr)
  6023  	case t.IsInterface():
  6024  		// itab field is treated as a scalar.
  6025  		idata := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, right)
  6026  		idataAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.BytePtrPtr, s.config.PtrSize, left)
  6027  		s.store(s.f.Config.Types.BytePtr, idataAddr, idata)
  6028  	case t.IsStruct():
  6029  		n := t.NumFields()
  6030  		for i := 0; i < n; i++ {
  6031  			ft := t.FieldType(i)
  6032  			if !ft.HasPointers() {
  6033  				continue
  6034  			}
  6035  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  6036  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  6037  			s.storeTypePtrs(ft, addr, val)
  6038  		}
  6039  	case t.IsArray() && t.NumElem() == 0:
  6040  		// nothing
  6041  	case t.IsArray() && t.NumElem() == 1:
  6042  		s.storeTypePtrs(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right))
  6043  	default:
  6044  		s.Fatalf("bad write barrier type %v", t)
  6045  	}
  6046  }
  6047  
  6048  // putArg evaluates n for the purpose of passing it as an argument to a function and returns the value for the call.
  6049  func (s *state) putArg(n ir.Node, t *types.Type) *ssa.Value {
  6050  	var a *ssa.Value
  6051  	if !ssa.CanSSA(t) {
  6052  		a = s.newValue2(ssa.OpDereference, t, s.addr(n), s.mem())
  6053  	} else {
  6054  		a = s.expr(n)
  6055  	}
  6056  	return a
  6057  }
  6058  
  6059  func (s *state) storeArgWithBase(n ir.Node, t *types.Type, base *ssa.Value, off int64) {
  6060  	pt := types.NewPtr(t)
  6061  	var addr *ssa.Value
  6062  	if base == s.sp {
  6063  		// Use special routine that avoids allocation on duplicate offsets.
  6064  		addr = s.constOffPtrSP(pt, off)
  6065  	} else {
  6066  		addr = s.newValue1I(ssa.OpOffPtr, pt, off, base)
  6067  	}
  6068  
  6069  	if !ssa.CanSSA(t) {
  6070  		a := s.addr(n)
  6071  		s.move(t, addr, a)
  6072  		return
  6073  	}
  6074  
  6075  	a := s.expr(n)
  6076  	s.storeType(t, addr, a, 0, false)
  6077  }
  6078  
  6079  // slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
  6080  // i,j,k may be nil, in which case they are set to their default value.
  6081  // v may be a slice, string or pointer to an array.
  6082  func (s *state) slice(v, i, j, k *ssa.Value, bounded bool) (p, l, c *ssa.Value) {
  6083  	t := v.Type
  6084  	var ptr, len, cap *ssa.Value
  6085  	switch {
  6086  	case t.IsSlice():
  6087  		ptr = s.newValue1(ssa.OpSlicePtr, types.NewPtr(t.Elem()), v)
  6088  		len = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  6089  		cap = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], v)
  6090  	case t.IsString():
  6091  		ptr = s.newValue1(ssa.OpStringPtr, types.NewPtr(types.Types[types.TUINT8]), v)
  6092  		len = s.newValue1(ssa.OpStringLen, types.Types[types.TINT], v)
  6093  		cap = len
  6094  	case t.IsPtr():
  6095  		if !t.Elem().IsArray() {
  6096  			s.Fatalf("bad ptr to array in slice %v\n", t)
  6097  		}
  6098  		nv := s.nilCheck(v)
  6099  		ptr = s.newValue1(ssa.OpCopy, types.NewPtr(t.Elem().Elem()), nv)
  6100  		len = s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  6101  		cap = len
  6102  	default:
  6103  		s.Fatalf("bad type in slice %v\n", t)
  6104  	}
  6105  
  6106  	// Set default values
  6107  	if i == nil {
  6108  		i = s.constInt(types.Types[types.TINT], 0)
  6109  	}
  6110  	if j == nil {
  6111  		j = len
  6112  	}
  6113  	three := true
  6114  	if k == nil {
  6115  		three = false
  6116  		k = cap
  6117  	}
  6118  
  6119  	// Panic if slice indices are not in bounds.
  6120  	// Make sure we check these in reverse order so that we're always
  6121  	// comparing against a value known to be nonnegative. See issue 28797.
  6122  	if three {
  6123  		if k != cap {
  6124  			kind := ssa.BoundsSlice3Alen
  6125  			if t.IsSlice() {
  6126  				kind = ssa.BoundsSlice3Acap
  6127  			}
  6128  			k = s.boundsCheck(k, cap, kind, bounded)
  6129  		}
  6130  		if j != k {
  6131  			j = s.boundsCheck(j, k, ssa.BoundsSlice3B, bounded)
  6132  		}
  6133  		i = s.boundsCheck(i, j, ssa.BoundsSlice3C, bounded)
  6134  	} else {
  6135  		if j != k {
  6136  			kind := ssa.BoundsSliceAlen
  6137  			if t.IsSlice() {
  6138  				kind = ssa.BoundsSliceAcap
  6139  			}
  6140  			j = s.boundsCheck(j, k, kind, bounded)
  6141  		}
  6142  		i = s.boundsCheck(i, j, ssa.BoundsSliceB, bounded)
  6143  	}
  6144  
  6145  	// Word-sized integer operations.
  6146  	subOp := s.ssaOp(ir.OSUB, types.Types[types.TINT])
  6147  	mulOp := s.ssaOp(ir.OMUL, types.Types[types.TINT])
  6148  	andOp := s.ssaOp(ir.OAND, types.Types[types.TINT])
  6149  
  6150  	// Calculate the length (rlen) and capacity (rcap) of the new slice.
  6151  	// For strings the capacity of the result is unimportant. However,
  6152  	// we use rcap to test if we've generated a zero-length slice.
  6153  	// Use length of strings for that.
  6154  	rlen := s.newValue2(subOp, types.Types[types.TINT], j, i)
  6155  	rcap := rlen
  6156  	if j != k && !t.IsString() {
  6157  		rcap = s.newValue2(subOp, types.Types[types.TINT], k, i)
  6158  	}
  6159  
  6160  	if (i.Op == ssa.OpConst64 || i.Op == ssa.OpConst32) && i.AuxInt == 0 {
  6161  		// No pointer arithmetic necessary.
  6162  		return ptr, rlen, rcap
  6163  	}
  6164  
  6165  	// Calculate the base pointer (rptr) for the new slice.
  6166  	//
  6167  	// Generate the following code assuming that indexes are in bounds.
  6168  	// The masking is to make sure that we don't generate a slice
  6169  	// that points to the next object in memory. We cannot just set
  6170  	// the pointer to nil because then we would create a nil slice or
  6171  	// string.
  6172  	//
  6173  	//     rcap = k - i
  6174  	//     rlen = j - i
  6175  	//     rptr = ptr + (mask(rcap) & (i * stride))
  6176  	//
  6177  	// Where mask(x) is 0 if x==0 and -1 if x>0 and stride is the width
  6178  	// of the element type.
  6179  	stride := s.constInt(types.Types[types.TINT], ptr.Type.Elem().Size())
  6180  
  6181  	// The delta is the number of bytes to offset ptr by.
  6182  	delta := s.newValue2(mulOp, types.Types[types.TINT], i, stride)
  6183  
  6184  	// If we're slicing to the point where the capacity is zero,
  6185  	// zero out the delta.
  6186  	mask := s.newValue1(ssa.OpSlicemask, types.Types[types.TINT], rcap)
  6187  	delta = s.newValue2(andOp, types.Types[types.TINT], delta, mask)
  6188  
  6189  	// Compute rptr = ptr + delta.
  6190  	rptr := s.newValue2(ssa.OpAddPtr, ptr.Type, ptr, delta)
  6191  
  6192  	return rptr, rlen, rcap
  6193  }
  6194  
  6195  type u642fcvtTab struct {
  6196  	leq, cvt2F, and, rsh, or, add ssa.Op
  6197  	one                           func(*state, *types.Type, int64) *ssa.Value
  6198  }
  6199  
  6200  var u64_f64 = u642fcvtTab{
  6201  	leq:   ssa.OpLeq64,
  6202  	cvt2F: ssa.OpCvt64to64F,
  6203  	and:   ssa.OpAnd64,
  6204  	rsh:   ssa.OpRsh64Ux64,
  6205  	or:    ssa.OpOr64,
  6206  	add:   ssa.OpAdd64F,
  6207  	one:   (*state).constInt64,
  6208  }
  6209  
  6210  var u64_f32 = u642fcvtTab{
  6211  	leq:   ssa.OpLeq64,
  6212  	cvt2F: ssa.OpCvt64to32F,
  6213  	and:   ssa.OpAnd64,
  6214  	rsh:   ssa.OpRsh64Ux64,
  6215  	or:    ssa.OpOr64,
  6216  	add:   ssa.OpAdd32F,
  6217  	one:   (*state).constInt64,
  6218  }
  6219  
  6220  func (s *state) uint64Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6221  	return s.uint64Tofloat(&u64_f64, n, x, ft, tt)
  6222  }
  6223  
  6224  func (s *state) uint64Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6225  	return s.uint64Tofloat(&u64_f32, n, x, ft, tt)
  6226  }
  6227  
  6228  func (s *state) uint64Tofloat(cvttab *u642fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6229  	// if x >= 0 {
  6230  	//    result = (floatY) x
  6231  	// } else {
  6232  	// 	  y = uintX(x) ; y = x & 1
  6233  	// 	  z = uintX(x) ; z = z >> 1
  6234  	// 	  z = z | y
  6235  	// 	  result = floatY(z)
  6236  	// 	  result = result + result
  6237  	// }
  6238  	//
  6239  	// Code borrowed from old code generator.
  6240  	// What's going on: large 64-bit "unsigned" looks like
  6241  	// negative number to hardware's integer-to-float
  6242  	// conversion. However, because the mantissa is only
  6243  	// 63 bits, we don't need the LSB, so instead we do an
  6244  	// unsigned right shift (divide by two), convert, and
  6245  	// double. However, before we do that, we need to be
  6246  	// sure that we do not lose a "1" if that made the
  6247  	// difference in the resulting rounding. Therefore, we
  6248  	// preserve it, and OR (not ADD) it back in. The case
  6249  	// that matters is when the eleven discarded bits are
  6250  	// equal to 10000000001; that rounds up, and the 1 cannot
  6251  	// be lost else it would round down if the LSB of the
  6252  	// candidate mantissa is 0.
  6253  	cmp := s.newValue2(cvttab.leq, types.Types[types.TBOOL], s.zeroVal(ft), x)
  6254  	b := s.endBlock()
  6255  	b.Kind = ssa.BlockIf
  6256  	b.SetControl(cmp)
  6257  	b.Likely = ssa.BranchLikely
  6258  
  6259  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6260  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6261  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6262  
  6263  	b.AddEdgeTo(bThen)
  6264  	s.startBlock(bThen)
  6265  	a0 := s.newValue1(cvttab.cvt2F, tt, x)
  6266  	s.vars[n] = a0
  6267  	s.endBlock()
  6268  	bThen.AddEdgeTo(bAfter)
  6269  
  6270  	b.AddEdgeTo(bElse)
  6271  	s.startBlock(bElse)
  6272  	one := cvttab.one(s, ft, 1)
  6273  	y := s.newValue2(cvttab.and, ft, x, one)
  6274  	z := s.newValue2(cvttab.rsh, ft, x, one)
  6275  	z = s.newValue2(cvttab.or, ft, z, y)
  6276  	a := s.newValue1(cvttab.cvt2F, tt, z)
  6277  	a1 := s.newValue2(cvttab.add, tt, a, a)
  6278  	s.vars[n] = a1
  6279  	s.endBlock()
  6280  	bElse.AddEdgeTo(bAfter)
  6281  
  6282  	s.startBlock(bAfter)
  6283  	return s.variable(n, n.Type())
  6284  }
  6285  
  6286  type u322fcvtTab struct {
  6287  	cvtI2F, cvtF2F ssa.Op
  6288  }
  6289  
  6290  var u32_f64 = u322fcvtTab{
  6291  	cvtI2F: ssa.OpCvt32to64F,
  6292  	cvtF2F: ssa.OpCopy,
  6293  }
  6294  
  6295  var u32_f32 = u322fcvtTab{
  6296  	cvtI2F: ssa.OpCvt32to32F,
  6297  	cvtF2F: ssa.OpCvt64Fto32F,
  6298  }
  6299  
  6300  func (s *state) uint32Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6301  	return s.uint32Tofloat(&u32_f64, n, x, ft, tt)
  6302  }
  6303  
  6304  func (s *state) uint32Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6305  	return s.uint32Tofloat(&u32_f32, n, x, ft, tt)
  6306  }
  6307  
  6308  func (s *state) uint32Tofloat(cvttab *u322fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6309  	// if x >= 0 {
  6310  	// 	result = floatY(x)
  6311  	// } else {
  6312  	// 	result = floatY(float64(x) + (1<<32))
  6313  	// }
  6314  	cmp := s.newValue2(ssa.OpLeq32, types.Types[types.TBOOL], s.zeroVal(ft), x)
  6315  	b := s.endBlock()
  6316  	b.Kind = ssa.BlockIf
  6317  	b.SetControl(cmp)
  6318  	b.Likely = ssa.BranchLikely
  6319  
  6320  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6321  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6322  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6323  
  6324  	b.AddEdgeTo(bThen)
  6325  	s.startBlock(bThen)
  6326  	a0 := s.newValue1(cvttab.cvtI2F, tt, x)
  6327  	s.vars[n] = a0
  6328  	s.endBlock()
  6329  	bThen.AddEdgeTo(bAfter)
  6330  
  6331  	b.AddEdgeTo(bElse)
  6332  	s.startBlock(bElse)
  6333  	a1 := s.newValue1(ssa.OpCvt32to64F, types.Types[types.TFLOAT64], x)
  6334  	twoToThe32 := s.constFloat64(types.Types[types.TFLOAT64], float64(1<<32))
  6335  	a2 := s.newValue2(ssa.OpAdd64F, types.Types[types.TFLOAT64], a1, twoToThe32)
  6336  	a3 := s.newValue1(cvttab.cvtF2F, tt, a2)
  6337  
  6338  	s.vars[n] = a3
  6339  	s.endBlock()
  6340  	bElse.AddEdgeTo(bAfter)
  6341  
  6342  	s.startBlock(bAfter)
  6343  	return s.variable(n, n.Type())
  6344  }
  6345  
  6346  // referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
  6347  func (s *state) referenceTypeBuiltin(n *ir.UnaryExpr, x *ssa.Value) *ssa.Value {
  6348  	if !n.X.Type().IsMap() && !n.X.Type().IsChan() {
  6349  		s.Fatalf("node must be a map or a channel")
  6350  	}
  6351  	// if n == nil {
  6352  	//   return 0
  6353  	// } else {
  6354  	//   // len
  6355  	//   return *((*int)n)
  6356  	//   // cap
  6357  	//   return *(((*int)n)+1)
  6358  	// }
  6359  	lenType := n.Type()
  6360  	nilValue := s.constNil(types.Types[types.TUINTPTR])
  6361  	cmp := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], x, nilValue)
  6362  	b := s.endBlock()
  6363  	b.Kind = ssa.BlockIf
  6364  	b.SetControl(cmp)
  6365  	b.Likely = ssa.BranchUnlikely
  6366  
  6367  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6368  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6369  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6370  
  6371  	// length/capacity of a nil map/chan is zero
  6372  	b.AddEdgeTo(bThen)
  6373  	s.startBlock(bThen)
  6374  	s.vars[n] = s.zeroVal(lenType)
  6375  	s.endBlock()
  6376  	bThen.AddEdgeTo(bAfter)
  6377  
  6378  	b.AddEdgeTo(bElse)
  6379  	s.startBlock(bElse)
  6380  	switch n.Op() {
  6381  	case ir.OLEN:
  6382  		// length is stored in the first word for map/chan
  6383  		s.vars[n] = s.load(lenType, x)
  6384  	case ir.OCAP:
  6385  		// capacity is stored in the second word for chan
  6386  		sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Size(), x)
  6387  		s.vars[n] = s.load(lenType, sw)
  6388  	default:
  6389  		s.Fatalf("op must be OLEN or OCAP")
  6390  	}
  6391  	s.endBlock()
  6392  	bElse.AddEdgeTo(bAfter)
  6393  
  6394  	s.startBlock(bAfter)
  6395  	return s.variable(n, lenType)
  6396  }
  6397  
  6398  type f2uCvtTab struct {
  6399  	ltf, cvt2U, subf, or ssa.Op
  6400  	floatValue           func(*state, *types.Type, float64) *ssa.Value
  6401  	intValue             func(*state, *types.Type, int64) *ssa.Value
  6402  	cutoff               uint64
  6403  }
  6404  
  6405  var f32_u64 = f2uCvtTab{
  6406  	ltf:        ssa.OpLess32F,
  6407  	cvt2U:      ssa.OpCvt32Fto64,
  6408  	subf:       ssa.OpSub32F,
  6409  	or:         ssa.OpOr64,
  6410  	floatValue: (*state).constFloat32,
  6411  	intValue:   (*state).constInt64,
  6412  	cutoff:     1 << 63,
  6413  }
  6414  
  6415  var f64_u64 = f2uCvtTab{
  6416  	ltf:        ssa.OpLess64F,
  6417  	cvt2U:      ssa.OpCvt64Fto64,
  6418  	subf:       ssa.OpSub64F,
  6419  	or:         ssa.OpOr64,
  6420  	floatValue: (*state).constFloat64,
  6421  	intValue:   (*state).constInt64,
  6422  	cutoff:     1 << 63,
  6423  }
  6424  
  6425  var f32_u32 = f2uCvtTab{
  6426  	ltf:        ssa.OpLess32F,
  6427  	cvt2U:      ssa.OpCvt32Fto32,
  6428  	subf:       ssa.OpSub32F,
  6429  	or:         ssa.OpOr32,
  6430  	floatValue: (*state).constFloat32,
  6431  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6432  	cutoff:     1 << 31,
  6433  }
  6434  
  6435  var f64_u32 = f2uCvtTab{
  6436  	ltf:        ssa.OpLess64F,
  6437  	cvt2U:      ssa.OpCvt64Fto32,
  6438  	subf:       ssa.OpSub64F,
  6439  	or:         ssa.OpOr32,
  6440  	floatValue: (*state).constFloat64,
  6441  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6442  	cutoff:     1 << 31,
  6443  }
  6444  
  6445  func (s *state) float32ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6446  	return s.floatToUint(&f32_u64, n, x, ft, tt)
  6447  }
  6448  func (s *state) float64ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6449  	return s.floatToUint(&f64_u64, n, x, ft, tt)
  6450  }
  6451  
  6452  func (s *state) float32ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6453  	return s.floatToUint(&f32_u32, n, x, ft, tt)
  6454  }
  6455  
  6456  func (s *state) float64ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6457  	return s.floatToUint(&f64_u32, n, x, ft, tt)
  6458  }
  6459  
  6460  func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6461  	// cutoff:=1<<(intY_Size-1)
  6462  	// if x < floatX(cutoff) {
  6463  	// 	result = uintY(x)
  6464  	// } else {
  6465  	// 	y = x - floatX(cutoff)
  6466  	// 	z = uintY(y)
  6467  	// 	result = z | -(cutoff)
  6468  	// }
  6469  	cutoff := cvttab.floatValue(s, ft, float64(cvttab.cutoff))
  6470  	cmp := s.newValue2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
  6471  	b := s.endBlock()
  6472  	b.Kind = ssa.BlockIf
  6473  	b.SetControl(cmp)
  6474  	b.Likely = ssa.BranchLikely
  6475  
  6476  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6477  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6478  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6479  
  6480  	b.AddEdgeTo(bThen)
  6481  	s.startBlock(bThen)
  6482  	a0 := s.newValue1(cvttab.cvt2U, tt, x)
  6483  	s.vars[n] = a0
  6484  	s.endBlock()
  6485  	bThen.AddEdgeTo(bAfter)
  6486  
  6487  	b.AddEdgeTo(bElse)
  6488  	s.startBlock(bElse)
  6489  	y := s.newValue2(cvttab.subf, ft, x, cutoff)
  6490  	y = s.newValue1(cvttab.cvt2U, tt, y)
  6491  	z := cvttab.intValue(s, tt, int64(-cvttab.cutoff))
  6492  	a1 := s.newValue2(cvttab.or, tt, y, z)
  6493  	s.vars[n] = a1
  6494  	s.endBlock()
  6495  	bElse.AddEdgeTo(bAfter)
  6496  
  6497  	s.startBlock(bAfter)
  6498  	return s.variable(n, n.Type())
  6499  }
  6500  
  6501  // dottype generates SSA for a type assertion node.
  6502  // commaok indicates whether to panic or return a bool.
  6503  // If commaok is false, resok will be nil.
  6504  func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6505  	iface := s.expr(n.X)              // input interface
  6506  	target := s.reflectType(n.Type()) // target type
  6507  	var targetItab *ssa.Value
  6508  	if n.ITab != nil {
  6509  		targetItab = s.expr(n.ITab)
  6510  	}
  6511  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, nil, target, targetItab, commaok, n.Descriptor)
  6512  }
  6513  
  6514  func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6515  	iface := s.expr(n.X)
  6516  	var source, target, targetItab *ssa.Value
  6517  	if n.SrcRType != nil {
  6518  		source = s.expr(n.SrcRType)
  6519  	}
  6520  	if !n.X.Type().IsEmptyInterface() && !n.Type().IsInterface() {
  6521  		byteptr := s.f.Config.Types.BytePtr
  6522  		targetItab = s.expr(n.ITab)
  6523  		// TODO(mdempsky): Investigate whether compiling n.RType could be
  6524  		// better than loading itab.typ.
  6525  		target = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, int64(types.PtrSize), targetItab)) // itab.typ
  6526  	} else {
  6527  		target = s.expr(n.RType)
  6528  	}
  6529  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, source, target, targetItab, commaok, nil)
  6530  }
  6531  
  6532  // dottype1 implements a x.(T) operation. iface is the argument (x), dst is the type we're asserting to (T)
  6533  // and src is the type we're asserting from.
  6534  // source is the *runtime._type of src
  6535  // target is the *runtime._type of dst.
  6536  // If src is a nonempty interface and dst is not an interface, targetItab is an itab representing (dst, src). Otherwise it is nil.
  6537  // commaok is true if the caller wants a boolean success value. Otherwise, the generated code panics if the conversion fails.
  6538  // descriptor is a compiler-allocated internal/abi.TypeAssert whose address is passed to runtime.typeAssert when
  6539  // the target type is a compile-time-known non-empty interface. It may be nil.
  6540  func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, source, target, targetItab *ssa.Value, commaok bool, descriptor *obj.LSym) (res, resok *ssa.Value) {
  6541  	typs := s.f.Config.Types
  6542  	byteptr := typs.BytePtr
  6543  	if dst.IsInterface() {
  6544  		if dst.IsEmptyInterface() {
  6545  			// Converting to an empty interface.
  6546  			// Input could be an empty or nonempty interface.
  6547  			if base.Debug.TypeAssert > 0 {
  6548  				base.WarnfAt(pos, "type assertion inlined")
  6549  			}
  6550  
  6551  			// Get itab/type field from input.
  6552  			itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6553  			// Conversion succeeds iff that field is not nil.
  6554  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6555  
  6556  			if src.IsEmptyInterface() && commaok {
  6557  				// Converting empty interface to empty interface with ,ok is just a nil check.
  6558  				return iface, cond
  6559  			}
  6560  
  6561  			// Branch on nilness.
  6562  			b := s.endBlock()
  6563  			b.Kind = ssa.BlockIf
  6564  			b.SetControl(cond)
  6565  			b.Likely = ssa.BranchLikely
  6566  			bOk := s.f.NewBlock(ssa.BlockPlain)
  6567  			bFail := s.f.NewBlock(ssa.BlockPlain)
  6568  			b.AddEdgeTo(bOk)
  6569  			b.AddEdgeTo(bFail)
  6570  
  6571  			if !commaok {
  6572  				// On failure, panic by calling panicnildottype.
  6573  				s.startBlock(bFail)
  6574  				s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6575  
  6576  				// On success, return (perhaps modified) input interface.
  6577  				s.startBlock(bOk)
  6578  				if src.IsEmptyInterface() {
  6579  					res = iface // Use input interface unchanged.
  6580  					return
  6581  				}
  6582  				// Load type out of itab, build interface with existing idata.
  6583  				off := s.newValue1I(ssa.OpOffPtr, byteptr, int64(types.PtrSize), itab)
  6584  				typ := s.load(byteptr, off)
  6585  				idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6586  				res = s.newValue2(ssa.OpIMake, dst, typ, idata)
  6587  				return
  6588  			}
  6589  
  6590  			s.startBlock(bOk)
  6591  			// nonempty -> empty
  6592  			// Need to load type from itab
  6593  			off := s.newValue1I(ssa.OpOffPtr, byteptr, int64(types.PtrSize), itab)
  6594  			s.vars[typVar] = s.load(byteptr, off)
  6595  			s.endBlock()
  6596  
  6597  			// itab is nil, might as well use that as the nil result.
  6598  			s.startBlock(bFail)
  6599  			s.vars[typVar] = itab
  6600  			s.endBlock()
  6601  
  6602  			// Merge point.
  6603  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  6604  			bOk.AddEdgeTo(bEnd)
  6605  			bFail.AddEdgeTo(bEnd)
  6606  			s.startBlock(bEnd)
  6607  			idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6608  			res = s.newValue2(ssa.OpIMake, dst, s.variable(typVar, byteptr), idata)
  6609  			resok = cond
  6610  			delete(s.vars, typVar) // no practical effect, just to indicate typVar is no longer live.
  6611  			return
  6612  		}
  6613  		// converting to a nonempty interface needs a runtime call.
  6614  		if base.Debug.TypeAssert > 0 {
  6615  			base.WarnfAt(pos, "type assertion not inlined")
  6616  		}
  6617  
  6618  		itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6619  		data := s.newValue1(ssa.OpIData, types.Types[types.TUNSAFEPTR], iface)
  6620  
  6621  		// First, check for nil.
  6622  		bNil := s.f.NewBlock(ssa.BlockPlain)
  6623  		bNonNil := s.f.NewBlock(ssa.BlockPlain)
  6624  		bMerge := s.f.NewBlock(ssa.BlockPlain)
  6625  		cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6626  		b := s.endBlock()
  6627  		b.Kind = ssa.BlockIf
  6628  		b.SetControl(cond)
  6629  		b.Likely = ssa.BranchLikely
  6630  		b.AddEdgeTo(bNonNil)
  6631  		b.AddEdgeTo(bNil)
  6632  
  6633  		s.startBlock(bNil)
  6634  		if commaok {
  6635  			s.vars[typVar] = itab // which will be nil
  6636  			b := s.endBlock()
  6637  			b.AddEdgeTo(bMerge)
  6638  		} else {
  6639  			// Panic if input is nil.
  6640  			s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6641  		}
  6642  
  6643  		// Get typ, possibly by loading out of itab.
  6644  		s.startBlock(bNonNil)
  6645  		typ := itab
  6646  		if !src.IsEmptyInterface() {
  6647  			typ = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, int64(types.PtrSize), itab))
  6648  		}
  6649  
  6650  		// Check the cache first.
  6651  		var d *ssa.Value
  6652  		if descriptor != nil {
  6653  			d = s.newValue1A(ssa.OpAddr, byteptr, descriptor, s.sb)
  6654  			if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Name) {
  6655  				// Note: we can only use the cache if we have the right atomic load instruction.
  6656  				// Double-check that here.
  6657  				if _, ok := intrinsics[intrinsicKey{Arch.LinkArch.Arch, "runtime/internal/atomic", "Loadp"}]; !ok {
  6658  					s.Fatalf("atomic load not available")
  6659  				}
  6660  				// Pick right size ops.
  6661  				var mul, and, add, zext ssa.Op
  6662  				if s.config.PtrSize == 4 {
  6663  					mul = ssa.OpMul32
  6664  					and = ssa.OpAnd32
  6665  					add = ssa.OpAdd32
  6666  					zext = ssa.OpCopy
  6667  				} else {
  6668  					mul = ssa.OpMul64
  6669  					and = ssa.OpAnd64
  6670  					add = ssa.OpAdd64
  6671  					zext = ssa.OpZeroExt32to64
  6672  				}
  6673  
  6674  				loopHead := s.f.NewBlock(ssa.BlockPlain)
  6675  				loopBody := s.f.NewBlock(ssa.BlockPlain)
  6676  				cacheHit := s.f.NewBlock(ssa.BlockPlain)
  6677  				cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  6678  
  6679  				// Load cache pointer out of descriptor, with an atomic load so
  6680  				// we ensure that we see a fully written cache.
  6681  				atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  6682  				cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  6683  				s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  6684  
  6685  				// Load hash from type or itab.
  6686  				var hash *ssa.Value
  6687  				if src.IsEmptyInterface() {
  6688  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, 2*s.config.PtrSize, typ), s.mem())
  6689  				} else {
  6690  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, 2*s.config.PtrSize, itab), s.mem())
  6691  				}
  6692  				hash = s.newValue1(zext, typs.Uintptr, hash)
  6693  				s.vars[hashVar] = hash
  6694  				// Load mask from cache.
  6695  				mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  6696  				// Jump to loop head.
  6697  				b := s.endBlock()
  6698  				b.AddEdgeTo(loopHead)
  6699  
  6700  				// At loop head, get pointer to the cache entry.
  6701  				//   e := &cache.Entries[hash&mask]
  6702  				s.startBlock(loopHead)
  6703  				idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  6704  				idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(2*s.config.PtrSize)))
  6705  				idx = s.newValue2(add, typs.Uintptr, idx, s.uintptrConstant(uint64(s.config.PtrSize)))
  6706  				e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, idx)
  6707  				//   hash++
  6708  				s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  6709  
  6710  				// Look for a cache hit.
  6711  				//   if e.Typ == typ { goto hit }
  6712  				eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  6713  				cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, typ, eTyp)
  6714  				b = s.endBlock()
  6715  				b.Kind = ssa.BlockIf
  6716  				b.SetControl(cmp1)
  6717  				b.AddEdgeTo(cacheHit)
  6718  				b.AddEdgeTo(loopBody)
  6719  
  6720  				// Look for an empty entry, the tombstone for this hash table.
  6721  				//   if e.Typ == nil { goto miss }
  6722  				s.startBlock(loopBody)
  6723  				cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  6724  				b = s.endBlock()
  6725  				b.Kind = ssa.BlockIf
  6726  				b.SetControl(cmp2)
  6727  				b.AddEdgeTo(cacheMiss)
  6728  				b.AddEdgeTo(loopHead)
  6729  
  6730  				// On a hit, load the data fields of the cache entry.
  6731  				//   Itab = e.Itab
  6732  				s.startBlock(cacheHit)
  6733  				eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, s.config.PtrSize, e), s.mem())
  6734  				s.vars[typVar] = eItab
  6735  				b = s.endBlock()
  6736  				b.AddEdgeTo(bMerge)
  6737  
  6738  				// On a miss, call into the runtime to get the answer.
  6739  				s.startBlock(cacheMiss)
  6740  			}
  6741  		}
  6742  
  6743  		// Call into runtime to get itab for result.
  6744  		if descriptor != nil {
  6745  			itab = s.rtcall(ir.Syms.TypeAssert, true, []*types.Type{byteptr}, d, typ)[0]
  6746  		} else {
  6747  			var fn *obj.LSym
  6748  			if commaok {
  6749  				fn = ir.Syms.AssertE2I2
  6750  			} else {
  6751  				fn = ir.Syms.AssertE2I
  6752  			}
  6753  			itab = s.rtcall(fn, true, []*types.Type{byteptr}, target, typ)[0]
  6754  		}
  6755  		s.vars[typVar] = itab
  6756  		b = s.endBlock()
  6757  		b.AddEdgeTo(bMerge)
  6758  
  6759  		// Build resulting interface.
  6760  		s.startBlock(bMerge)
  6761  		itab = s.variable(typVar, byteptr)
  6762  		var ok *ssa.Value
  6763  		if commaok {
  6764  			ok = s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6765  		}
  6766  		return s.newValue2(ssa.OpIMake, dst, itab, data), ok
  6767  	}
  6768  
  6769  	if base.Debug.TypeAssert > 0 {
  6770  		base.WarnfAt(pos, "type assertion inlined")
  6771  	}
  6772  
  6773  	// Converting to a concrete type.
  6774  	direct := types.IsDirectIface(dst)
  6775  	itab := s.newValue1(ssa.OpITab, byteptr, iface) // type word of interface
  6776  	if base.Debug.TypeAssert > 0 {
  6777  		base.WarnfAt(pos, "type assertion inlined")
  6778  	}
  6779  	var wantedFirstWord *ssa.Value
  6780  	if src.IsEmptyInterface() {
  6781  		// Looking for pointer to target type.
  6782  		wantedFirstWord = target
  6783  	} else {
  6784  		// Looking for pointer to itab for target type and source interface.
  6785  		wantedFirstWord = targetItab
  6786  	}
  6787  
  6788  	var tmp ir.Node     // temporary for use with large types
  6789  	var addr *ssa.Value // address of tmp
  6790  	if commaok && !ssa.CanSSA(dst) {
  6791  		// unSSAable type, use temporary.
  6792  		// TODO: get rid of some of these temporaries.
  6793  		tmp, addr = s.temp(pos, dst)
  6794  	}
  6795  
  6796  	cond := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], itab, wantedFirstWord)
  6797  	b := s.endBlock()
  6798  	b.Kind = ssa.BlockIf
  6799  	b.SetControl(cond)
  6800  	b.Likely = ssa.BranchLikely
  6801  
  6802  	bOk := s.f.NewBlock(ssa.BlockPlain)
  6803  	bFail := s.f.NewBlock(ssa.BlockPlain)
  6804  	b.AddEdgeTo(bOk)
  6805  	b.AddEdgeTo(bFail)
  6806  
  6807  	if !commaok {
  6808  		// on failure, panic by calling panicdottype
  6809  		s.startBlock(bFail)
  6810  		taddr := source
  6811  		if taddr == nil {
  6812  			taddr = s.reflectType(src)
  6813  		}
  6814  		if src.IsEmptyInterface() {
  6815  			s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
  6816  		} else {
  6817  			s.rtcall(ir.Syms.PanicdottypeI, false, nil, itab, target, taddr)
  6818  		}
  6819  
  6820  		// on success, return data from interface
  6821  		s.startBlock(bOk)
  6822  		if direct {
  6823  			return s.newValue1(ssa.OpIData, dst, iface), nil
  6824  		}
  6825  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6826  		return s.load(dst, p), nil
  6827  	}
  6828  
  6829  	// commaok is the more complicated case because we have
  6830  	// a control flow merge point.
  6831  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  6832  	// Note that we need a new valVar each time (unlike okVar where we can
  6833  	// reuse the variable) because it might have a different type every time.
  6834  	valVar := ssaMarker("val")
  6835  
  6836  	// type assertion succeeded
  6837  	s.startBlock(bOk)
  6838  	if tmp == nil {
  6839  		if direct {
  6840  			s.vars[valVar] = s.newValue1(ssa.OpIData, dst, iface)
  6841  		} else {
  6842  			p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6843  			s.vars[valVar] = s.load(dst, p)
  6844  		}
  6845  	} else {
  6846  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6847  		s.move(dst, addr, p)
  6848  	}
  6849  	s.vars[okVar] = s.constBool(true)
  6850  	s.endBlock()
  6851  	bOk.AddEdgeTo(bEnd)
  6852  
  6853  	// type assertion failed
  6854  	s.startBlock(bFail)
  6855  	if tmp == nil {
  6856  		s.vars[valVar] = s.zeroVal(dst)
  6857  	} else {
  6858  		s.zero(dst, addr)
  6859  	}
  6860  	s.vars[okVar] = s.constBool(false)
  6861  	s.endBlock()
  6862  	bFail.AddEdgeTo(bEnd)
  6863  
  6864  	// merge point
  6865  	s.startBlock(bEnd)
  6866  	if tmp == nil {
  6867  		res = s.variable(valVar, dst)
  6868  		delete(s.vars, valVar) // no practical effect, just to indicate typVar is no longer live.
  6869  	} else {
  6870  		res = s.load(dst, addr)
  6871  	}
  6872  	resok = s.variable(okVar, types.Types[types.TBOOL])
  6873  	delete(s.vars, okVar) // ditto
  6874  	return res, resok
  6875  }
  6876  
  6877  // temp allocates a temp of type t at position pos
  6878  func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) {
  6879  	tmp := typecheck.TempAt(pos, s.curfn, t)
  6880  	if t.HasPointers() {
  6881  		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem())
  6882  	}
  6883  	addr := s.addr(tmp)
  6884  	return tmp, addr
  6885  }
  6886  
  6887  // variable returns the value of a variable at the current location.
  6888  func (s *state) variable(n ir.Node, t *types.Type) *ssa.Value {
  6889  	v := s.vars[n]
  6890  	if v != nil {
  6891  		return v
  6892  	}
  6893  	v = s.fwdVars[n]
  6894  	if v != nil {
  6895  		return v
  6896  	}
  6897  
  6898  	if s.curBlock == s.f.Entry {
  6899  		// No variable should be live at entry.
  6900  		s.f.Fatalf("value %v (%v) incorrectly live at entry", n, v)
  6901  	}
  6902  	// Make a FwdRef, which records a value that's live on block input.
  6903  	// We'll find the matching definition as part of insertPhis.
  6904  	v = s.newValue0A(ssa.OpFwdRef, t, fwdRefAux{N: n})
  6905  	s.fwdVars[n] = v
  6906  	if n.Op() == ir.ONAME {
  6907  		s.addNamedValue(n.(*ir.Name), v)
  6908  	}
  6909  	return v
  6910  }
  6911  
  6912  func (s *state) mem() *ssa.Value {
  6913  	return s.variable(memVar, types.TypeMem)
  6914  }
  6915  
  6916  func (s *state) addNamedValue(n *ir.Name, v *ssa.Value) {
  6917  	if n.Class == ir.Pxxx {
  6918  		// Don't track our marker nodes (memVar etc.).
  6919  		return
  6920  	}
  6921  	if ir.IsAutoTmp(n) {
  6922  		// Don't track temporary variables.
  6923  		return
  6924  	}
  6925  	if n.Class == ir.PPARAMOUT {
  6926  		// Don't track named output values.  This prevents return values
  6927  		// from being assigned too early. See #14591 and #14762. TODO: allow this.
  6928  		return
  6929  	}
  6930  	loc := ssa.LocalSlot{N: n, Type: n.Type(), Off: 0}
  6931  	values, ok := s.f.NamedValues[loc]
  6932  	if !ok {
  6933  		s.f.Names = append(s.f.Names, &loc)
  6934  		s.f.CanonicalLocalSlots[loc] = &loc
  6935  	}
  6936  	s.f.NamedValues[loc] = append(values, v)
  6937  }
  6938  
  6939  // Branch is an unresolved branch.
  6940  type Branch struct {
  6941  	P *obj.Prog  // branch instruction
  6942  	B *ssa.Block // target
  6943  }
  6944  
  6945  // State contains state needed during Prog generation.
  6946  type State struct {
  6947  	ABI obj.ABI
  6948  
  6949  	pp *objw.Progs
  6950  
  6951  	// Branches remembers all the branch instructions we've seen
  6952  	// and where they would like to go.
  6953  	Branches []Branch
  6954  
  6955  	// JumpTables remembers all the jump tables we've seen.
  6956  	JumpTables []*ssa.Block
  6957  
  6958  	// bstart remembers where each block starts (indexed by block ID)
  6959  	bstart []*obj.Prog
  6960  
  6961  	maxarg int64 // largest frame size for arguments to calls made by the function
  6962  
  6963  	// Map from GC safe points to liveness index, generated by
  6964  	// liveness analysis.
  6965  	livenessMap liveness.Map
  6966  
  6967  	// partLiveArgs includes arguments that may be partially live, for which we
  6968  	// need to generate instructions that spill the argument registers.
  6969  	partLiveArgs map[*ir.Name]bool
  6970  
  6971  	// lineRunStart records the beginning of the current run of instructions
  6972  	// within a single block sharing the same line number
  6973  	// Used to move statement marks to the beginning of such runs.
  6974  	lineRunStart *obj.Prog
  6975  
  6976  	// wasm: The number of values on the WebAssembly stack. This is only used as a safeguard.
  6977  	OnWasmStackSkipped int
  6978  }
  6979  
  6980  func (s *State) FuncInfo() *obj.FuncInfo {
  6981  	return s.pp.CurFunc.LSym.Func()
  6982  }
  6983  
  6984  // Prog appends a new Prog.
  6985  func (s *State) Prog(as obj.As) *obj.Prog {
  6986  	p := s.pp.Prog(as)
  6987  	if objw.LosesStmtMark(as) {
  6988  		return p
  6989  	}
  6990  	// Float a statement start to the beginning of any same-line run.
  6991  	// lineRunStart is reset at block boundaries, which appears to work well.
  6992  	if s.lineRunStart == nil || s.lineRunStart.Pos.Line() != p.Pos.Line() {
  6993  		s.lineRunStart = p
  6994  	} else if p.Pos.IsStmt() == src.PosIsStmt {
  6995  		s.lineRunStart.Pos = s.lineRunStart.Pos.WithIsStmt()
  6996  		p.Pos = p.Pos.WithNotStmt()
  6997  	}
  6998  	return p
  6999  }
  7000  
  7001  // Pc returns the current Prog.
  7002  func (s *State) Pc() *obj.Prog {
  7003  	return s.pp.Next
  7004  }
  7005  
  7006  // SetPos sets the current source position.
  7007  func (s *State) SetPos(pos src.XPos) {
  7008  	s.pp.Pos = pos
  7009  }
  7010  
  7011  // Br emits a single branch instruction and returns the instruction.
  7012  // Not all architectures need the returned instruction, but otherwise
  7013  // the boilerplate is common to all.
  7014  func (s *State) Br(op obj.As, target *ssa.Block) *obj.Prog {
  7015  	p := s.Prog(op)
  7016  	p.To.Type = obj.TYPE_BRANCH
  7017  	s.Branches = append(s.Branches, Branch{P: p, B: target})
  7018  	return p
  7019  }
  7020  
  7021  // DebugFriendlySetPosFrom adjusts Pos.IsStmt subject to heuristics
  7022  // that reduce "jumpy" line number churn when debugging.
  7023  // Spill/fill/copy instructions from the register allocator,
  7024  // phi functions, and instructions with a no-pos position
  7025  // are examples of instructions that can cause churn.
  7026  func (s *State) DebugFriendlySetPosFrom(v *ssa.Value) {
  7027  	switch v.Op {
  7028  	case ssa.OpPhi, ssa.OpCopy, ssa.OpLoadReg, ssa.OpStoreReg:
  7029  		// These are not statements
  7030  		s.SetPos(v.Pos.WithNotStmt())
  7031  	default:
  7032  		p := v.Pos
  7033  		if p != src.NoXPos {
  7034  			// If the position is defined, update the position.
  7035  			// Also convert default IsStmt to NotStmt; only
  7036  			// explicit statement boundaries should appear
  7037  			// in the generated code.
  7038  			if p.IsStmt() != src.PosIsStmt {
  7039  				if s.pp.Pos.IsStmt() == src.PosIsStmt && s.pp.Pos.SameFileAndLine(p) {
  7040  					// If s.pp.Pos already has a statement mark, then it was set here (below) for
  7041  					// the previous value.  If an actual instruction had been emitted for that
  7042  					// value, then the statement mark would have been reset.  Since the statement
  7043  					// mark of s.pp.Pos was not reset, this position (file/line) still needs a
  7044  					// statement mark on an instruction.  If file and line for this value are
  7045  					// the same as the previous value, then the first instruction for this
  7046  					// value will work to take the statement mark.  Return early to avoid
  7047  					// resetting the statement mark.
  7048  					//
  7049  					// The reset of s.pp.Pos occurs in (*Progs).Prog() -- if it emits
  7050  					// an instruction, and the instruction's statement mark was set,
  7051  					// and it is not one of the LosesStmtMark instructions,
  7052  					// then Prog() resets the statement mark on the (*Progs).Pos.
  7053  					return
  7054  				}
  7055  				p = p.WithNotStmt()
  7056  				// Calls use the pos attached to v, but copy the statement mark from State
  7057  			}
  7058  			s.SetPos(p)
  7059  		} else {
  7060  			s.SetPos(s.pp.Pos.WithNotStmt())
  7061  		}
  7062  	}
  7063  }
  7064  
  7065  // emit argument info (locations on stack) for traceback.
  7066  func emitArgInfo(e *ssafn, f *ssa.Func, pp *objw.Progs) {
  7067  	ft := e.curfn.Type()
  7068  	if ft.NumRecvs() == 0 && ft.NumParams() == 0 {
  7069  		return
  7070  	}
  7071  
  7072  	x := EmitArgInfo(e.curfn, f.OwnAux.ABIInfo())
  7073  	x.Set(obj.AttrContentAddressable, true)
  7074  	e.curfn.LSym.Func().ArgInfo = x
  7075  
  7076  	// Emit a funcdata pointing at the arg info data.
  7077  	p := pp.Prog(obj.AFUNCDATA)
  7078  	p.From.SetConst(rtabi.FUNCDATA_ArgInfo)
  7079  	p.To.Type = obj.TYPE_MEM
  7080  	p.To.Name = obj.NAME_EXTERN
  7081  	p.To.Sym = x
  7082  }
  7083  
  7084  // emit argument info (locations on stack) of f for traceback.
  7085  func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
  7086  	x := base.Ctxt.Lookup(fmt.Sprintf("%s.arginfo%d", f.LSym.Name, f.ABI))
  7087  	// NOTE: do not set ContentAddressable here. This may be referenced from
  7088  	// assembly code by name (in this case f is a declaration).
  7089  	// Instead, set it in emitArgInfo above.
  7090  
  7091  	PtrSize := int64(types.PtrSize)
  7092  	uintptrTyp := types.Types[types.TUINTPTR]
  7093  
  7094  	isAggregate := func(t *types.Type) bool {
  7095  		return t.IsStruct() || t.IsArray() || t.IsComplex() || t.IsInterface() || t.IsString() || t.IsSlice()
  7096  	}
  7097  
  7098  	// Populate the data.
  7099  	// The data is a stream of bytes, which contains the offsets and sizes of the
  7100  	// non-aggregate arguments or non-aggregate fields/elements of aggregate-typed
  7101  	// arguments, along with special "operators". Specifically,
  7102  	// - for each non-aggrgate arg/field/element, its offset from FP (1 byte) and
  7103  	//   size (1 byte)
  7104  	// - special operators:
  7105  	//   - 0xff - end of sequence
  7106  	//   - 0xfe - print { (at the start of an aggregate-typed argument)
  7107  	//   - 0xfd - print } (at the end of an aggregate-typed argument)
  7108  	//   - 0xfc - print ... (more args/fields/elements)
  7109  	//   - 0xfb - print _ (offset too large)
  7110  	// These constants need to be in sync with runtime.traceback.go:printArgs.
  7111  	const (
  7112  		_endSeq         = 0xff
  7113  		_startAgg       = 0xfe
  7114  		_endAgg         = 0xfd
  7115  		_dotdotdot      = 0xfc
  7116  		_offsetTooLarge = 0xfb
  7117  		_special        = 0xf0 // above this are operators, below this are ordinary offsets
  7118  	)
  7119  
  7120  	const (
  7121  		limit    = 10 // print no more than 10 args/components
  7122  		maxDepth = 5  // no more than 5 layers of nesting
  7123  
  7124  		// maxLen is a (conservative) upper bound of the byte stream length. For
  7125  		// each arg/component, it has no more than 2 bytes of data (size, offset),
  7126  		// and no more than one {, }, ... at each level (it cannot have both the
  7127  		// data and ... unless it is the last one, just be conservative). Plus 1
  7128  		// for _endSeq.
  7129  		maxLen = (maxDepth*3+2)*limit + 1
  7130  	)
  7131  
  7132  	wOff := 0
  7133  	n := 0
  7134  	writebyte := func(o uint8) { wOff = objw.Uint8(x, wOff, o) }
  7135  
  7136  	// Write one non-aggregate arg/field/element.
  7137  	write1 := func(sz, offset int64) {
  7138  		if offset >= _special {
  7139  			writebyte(_offsetTooLarge)
  7140  		} else {
  7141  			writebyte(uint8(offset))
  7142  			writebyte(uint8(sz))
  7143  		}
  7144  		n++
  7145  	}
  7146  
  7147  	// Visit t recursively and write it out.
  7148  	// Returns whether to continue visiting.
  7149  	var visitType func(baseOffset int64, t *types.Type, depth int) bool
  7150  	visitType = func(baseOffset int64, t *types.Type, depth int) bool {
  7151  		if n >= limit {
  7152  			writebyte(_dotdotdot)
  7153  			return false
  7154  		}
  7155  		if !isAggregate(t) {
  7156  			write1(t.Size(), baseOffset)
  7157  			return true
  7158  		}
  7159  		writebyte(_startAgg)
  7160  		depth++
  7161  		if depth >= maxDepth {
  7162  			writebyte(_dotdotdot)
  7163  			writebyte(_endAgg)
  7164  			n++
  7165  			return true
  7166  		}
  7167  		switch {
  7168  		case t.IsInterface(), t.IsString():
  7169  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  7170  				visitType(baseOffset+PtrSize, uintptrTyp, depth)
  7171  		case t.IsSlice():
  7172  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  7173  				visitType(baseOffset+PtrSize, uintptrTyp, depth) &&
  7174  				visitType(baseOffset+PtrSize*2, uintptrTyp, depth)
  7175  		case t.IsComplex():
  7176  			_ = visitType(baseOffset, types.FloatForComplex(t), depth) &&
  7177  				visitType(baseOffset+t.Size()/2, types.FloatForComplex(t), depth)
  7178  		case t.IsArray():
  7179  			if t.NumElem() == 0 {
  7180  				n++ // {} counts as a component
  7181  				break
  7182  			}
  7183  			for i := int64(0); i < t.NumElem(); i++ {
  7184  				if !visitType(baseOffset, t.Elem(), depth) {
  7185  					break
  7186  				}
  7187  				baseOffset += t.Elem().Size()
  7188  			}
  7189  		case t.IsStruct():
  7190  			if t.NumFields() == 0 {
  7191  				n++ // {} counts as a component
  7192  				break
  7193  			}
  7194  			for _, field := range t.Fields() {
  7195  				if !visitType(baseOffset+field.Offset, field.Type, depth) {
  7196  					break
  7197  				}
  7198  			}
  7199  		}
  7200  		writebyte(_endAgg)
  7201  		return true
  7202  	}
  7203  
  7204  	start := 0
  7205  	if strings.Contains(f.LSym.Name, "[") {
  7206  		// Skip the dictionary argument - it is implicit and the user doesn't need to see it.
  7207  		start = 1
  7208  	}
  7209  
  7210  	for _, a := range abiInfo.InParams()[start:] {
  7211  		if !visitType(a.FrameOffset(abiInfo), a.Type, 0) {
  7212  			break
  7213  		}
  7214  	}
  7215  	writebyte(_endSeq)
  7216  	if wOff > maxLen {
  7217  		base.Fatalf("ArgInfo too large")
  7218  	}
  7219  
  7220  	return x
  7221  }
  7222  
  7223  // for wrapper, emit info of wrapped function.
  7224  func emitWrappedFuncInfo(e *ssafn, pp *objw.Progs) {
  7225  	if base.Ctxt.Flag_linkshared {
  7226  		// Relative reference (SymPtrOff) to another shared object doesn't work.
  7227  		// Unfortunate.
  7228  		return
  7229  	}
  7230  
  7231  	wfn := e.curfn.WrappedFunc
  7232  	if wfn == nil {
  7233  		return
  7234  	}
  7235  
  7236  	wsym := wfn.Linksym()
  7237  	x := base.Ctxt.LookupInit(fmt.Sprintf("%s.wrapinfo", wsym.Name), func(x *obj.LSym) {
  7238  		objw.SymPtrOff(x, 0, wsym)
  7239  		x.Set(obj.AttrContentAddressable, true)
  7240  	})
  7241  	e.curfn.LSym.Func().WrapInfo = x
  7242  
  7243  	// Emit a funcdata pointing at the wrap info data.
  7244  	p := pp.Prog(obj.AFUNCDATA)
  7245  	p.From.SetConst(rtabi.FUNCDATA_WrapInfo)
  7246  	p.To.Type = obj.TYPE_MEM
  7247  	p.To.Name = obj.NAME_EXTERN
  7248  	p.To.Sym = x
  7249  }
  7250  
  7251  // genssa appends entries to pp for each instruction in f.
  7252  func genssa(f *ssa.Func, pp *objw.Progs) {
  7253  	var s State
  7254  	s.ABI = f.OwnAux.Fn.ABI()
  7255  
  7256  	e := f.Frontend().(*ssafn)
  7257  
  7258  	s.livenessMap, s.partLiveArgs = liveness.Compute(e.curfn, f, e.stkptrsize, pp)
  7259  	emitArgInfo(e, f, pp)
  7260  	argLiveBlockMap, argLiveValueMap := liveness.ArgLiveness(e.curfn, f, pp)
  7261  
  7262  	openDeferInfo := e.curfn.LSym.Func().OpenCodedDeferInfo
  7263  	if openDeferInfo != nil {
  7264  		// This function uses open-coded defers -- write out the funcdata
  7265  		// info that we computed at the end of genssa.
  7266  		p := pp.Prog(obj.AFUNCDATA)
  7267  		p.From.SetConst(rtabi.FUNCDATA_OpenCodedDeferInfo)
  7268  		p.To.Type = obj.TYPE_MEM
  7269  		p.To.Name = obj.NAME_EXTERN
  7270  		p.To.Sym = openDeferInfo
  7271  	}
  7272  
  7273  	emitWrappedFuncInfo(e, pp)
  7274  
  7275  	// Remember where each block starts.
  7276  	s.bstart = make([]*obj.Prog, f.NumBlocks())
  7277  	s.pp = pp
  7278  	var progToValue map[*obj.Prog]*ssa.Value
  7279  	var progToBlock map[*obj.Prog]*ssa.Block
  7280  	var valueToProgAfter []*obj.Prog // The first Prog following computation of a value v; v is visible at this point.
  7281  	gatherPrintInfo := f.PrintOrHtmlSSA || ssa.GenssaDump[f.Name]
  7282  	if gatherPrintInfo {
  7283  		progToValue = make(map[*obj.Prog]*ssa.Value, f.NumValues())
  7284  		progToBlock = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
  7285  		f.Logf("genssa %s\n", f.Name)
  7286  		progToBlock[s.pp.Next] = f.Blocks[0]
  7287  	}
  7288  
  7289  	if base.Ctxt.Flag_locationlists {
  7290  		if cap(f.Cache.ValueToProgAfter) < f.NumValues() {
  7291  			f.Cache.ValueToProgAfter = make([]*obj.Prog, f.NumValues())
  7292  		}
  7293  		valueToProgAfter = f.Cache.ValueToProgAfter[:f.NumValues()]
  7294  		for i := range valueToProgAfter {
  7295  			valueToProgAfter[i] = nil
  7296  		}
  7297  	}
  7298  
  7299  	// If the very first instruction is not tagged as a statement,
  7300  	// debuggers may attribute it to previous function in program.
  7301  	firstPos := src.NoXPos
  7302  	for _, v := range f.Entry.Values {
  7303  		if v.Pos.IsStmt() == src.PosIsStmt && v.Op != ssa.OpArg && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  7304  			firstPos = v.Pos
  7305  			v.Pos = firstPos.WithDefaultStmt()
  7306  			break
  7307  		}
  7308  	}
  7309  
  7310  	// inlMarks has an entry for each Prog that implements an inline mark.
  7311  	// It maps from that Prog to the global inlining id of the inlined body
  7312  	// which should unwind to this Prog's location.
  7313  	var inlMarks map[*obj.Prog]int32
  7314  	var inlMarkList []*obj.Prog
  7315  
  7316  	// inlMarksByPos maps from a (column 1) source position to the set of
  7317  	// Progs that are in the set above and have that source position.
  7318  	var inlMarksByPos map[src.XPos][]*obj.Prog
  7319  
  7320  	var argLiveIdx int = -1 // argument liveness info index
  7321  
  7322  	// Emit basic blocks
  7323  	for i, b := range f.Blocks {
  7324  		s.bstart[b.ID] = s.pp.Next
  7325  		s.lineRunStart = nil
  7326  		s.SetPos(s.pp.Pos.WithNotStmt()) // It needs a non-empty Pos, but cannot be a statement boundary (yet).
  7327  
  7328  		if idx, ok := argLiveBlockMap[b.ID]; ok && idx != argLiveIdx {
  7329  			argLiveIdx = idx
  7330  			p := s.pp.Prog(obj.APCDATA)
  7331  			p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7332  			p.To.SetConst(int64(idx))
  7333  		}
  7334  
  7335  		// Emit values in block
  7336  		Arch.SSAMarkMoves(&s, b)
  7337  		for _, v := range b.Values {
  7338  			x := s.pp.Next
  7339  			s.DebugFriendlySetPosFrom(v)
  7340  
  7341  			if v.Op.ResultInArg0() && v.ResultReg() != v.Args[0].Reg() {
  7342  				v.Fatalf("input[0] and output not in same register %s", v.LongString())
  7343  			}
  7344  
  7345  			switch v.Op {
  7346  			case ssa.OpInitMem:
  7347  				// memory arg needs no code
  7348  			case ssa.OpArg:
  7349  				// input args need no code
  7350  			case ssa.OpSP, ssa.OpSB:
  7351  				// nothing to do
  7352  			case ssa.OpSelect0, ssa.OpSelect1, ssa.OpSelectN, ssa.OpMakeResult:
  7353  				// nothing to do
  7354  			case ssa.OpGetG:
  7355  				// nothing to do when there's a g register,
  7356  				// and checkLower complains if there's not
  7357  			case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive, ssa.OpWBend:
  7358  				// nothing to do; already used by liveness
  7359  			case ssa.OpPhi:
  7360  				CheckLoweredPhi(v)
  7361  			case ssa.OpConvert:
  7362  				// nothing to do; no-op conversion for liveness
  7363  				if v.Args[0].Reg() != v.Reg() {
  7364  					v.Fatalf("OpConvert should be a no-op: %s; %s", v.Args[0].LongString(), v.LongString())
  7365  				}
  7366  			case ssa.OpInlMark:
  7367  				p := Arch.Ginsnop(s.pp)
  7368  				if inlMarks == nil {
  7369  					inlMarks = map[*obj.Prog]int32{}
  7370  					inlMarksByPos = map[src.XPos][]*obj.Prog{}
  7371  				}
  7372  				inlMarks[p] = v.AuxInt32()
  7373  				inlMarkList = append(inlMarkList, p)
  7374  				pos := v.Pos.AtColumn1()
  7375  				inlMarksByPos[pos] = append(inlMarksByPos[pos], p)
  7376  				firstPos = src.NoXPos
  7377  
  7378  			default:
  7379  				// Special case for first line in function; move it to the start (which cannot be a register-valued instruction)
  7380  				if firstPos != src.NoXPos && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  7381  					s.SetPos(firstPos)
  7382  					firstPos = src.NoXPos
  7383  				}
  7384  				// Attach this safe point to the next
  7385  				// instruction.
  7386  				s.pp.NextLive = s.livenessMap.Get(v)
  7387  				s.pp.NextUnsafe = s.livenessMap.GetUnsafe(v)
  7388  
  7389  				// let the backend handle it
  7390  				Arch.SSAGenValue(&s, v)
  7391  			}
  7392  
  7393  			if idx, ok := argLiveValueMap[v.ID]; ok && idx != argLiveIdx {
  7394  				argLiveIdx = idx
  7395  				p := s.pp.Prog(obj.APCDATA)
  7396  				p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7397  				p.To.SetConst(int64(idx))
  7398  			}
  7399  
  7400  			if base.Ctxt.Flag_locationlists {
  7401  				valueToProgAfter[v.ID] = s.pp.Next
  7402  			}
  7403  
  7404  			if gatherPrintInfo {
  7405  				for ; x != s.pp.Next; x = x.Link {
  7406  					progToValue[x] = v
  7407  				}
  7408  			}
  7409  		}
  7410  		// If this is an empty infinite loop, stick a hardware NOP in there so that debuggers are less confused.
  7411  		if s.bstart[b.ID] == s.pp.Next && len(b.Succs) == 1 && b.Succs[0].Block() == b {
  7412  			p := Arch.Ginsnop(s.pp)
  7413  			p.Pos = p.Pos.WithIsStmt()
  7414  			if b.Pos == src.NoXPos {
  7415  				b.Pos = p.Pos // It needs a file, otherwise a no-file non-zero line causes confusion.  See #35652.
  7416  				if b.Pos == src.NoXPos {
  7417  					b.Pos = pp.Text.Pos // Sometimes p.Pos is empty.  See #35695.
  7418  				}
  7419  			}
  7420  			b.Pos = b.Pos.WithBogusLine() // Debuggers are not good about infinite loops, force a change in line number
  7421  		}
  7422  
  7423  		// Set unsafe mark for any end-of-block generated instructions
  7424  		// (normally, conditional or unconditional branches).
  7425  		// This is particularly important for empty blocks, as there
  7426  		// are no values to inherit the unsafe mark from.
  7427  		s.pp.NextUnsafe = s.livenessMap.GetUnsafeBlock(b)
  7428  
  7429  		// Emit control flow instructions for block
  7430  		var next *ssa.Block
  7431  		if i < len(f.Blocks)-1 && base.Flag.N == 0 {
  7432  			// If -N, leave next==nil so every block with successors
  7433  			// ends in a JMP (except call blocks - plive doesn't like
  7434  			// select{send,recv} followed by a JMP call).  Helps keep
  7435  			// line numbers for otherwise empty blocks.
  7436  			next = f.Blocks[i+1]
  7437  		}
  7438  		x := s.pp.Next
  7439  		s.SetPos(b.Pos)
  7440  		Arch.SSAGenBlock(&s, b, next)
  7441  		if gatherPrintInfo {
  7442  			for ; x != s.pp.Next; x = x.Link {
  7443  				progToBlock[x] = b
  7444  			}
  7445  		}
  7446  	}
  7447  	if f.Blocks[len(f.Blocks)-1].Kind == ssa.BlockExit {
  7448  		// We need the return address of a panic call to
  7449  		// still be inside the function in question. So if
  7450  		// it ends in a call which doesn't return, add a
  7451  		// nop (which will never execute) after the call.
  7452  		Arch.Ginsnop(pp)
  7453  	}
  7454  	if openDeferInfo != nil {
  7455  		// When doing open-coded defers, generate a disconnected call to
  7456  		// deferreturn and a return. This will be used to during panic
  7457  		// recovery to unwind the stack and return back to the runtime.
  7458  		s.pp.NextLive = s.livenessMap.DeferReturn
  7459  		p := pp.Prog(obj.ACALL)
  7460  		p.To.Type = obj.TYPE_MEM
  7461  		p.To.Name = obj.NAME_EXTERN
  7462  		p.To.Sym = ir.Syms.Deferreturn
  7463  
  7464  		// Load results into registers. So when a deferred function
  7465  		// recovers a panic, it will return to caller with right results.
  7466  		// The results are already in memory, because they are not SSA'd
  7467  		// when the function has defers (see canSSAName).
  7468  		for _, o := range f.OwnAux.ABIInfo().OutParams() {
  7469  			n := o.Name
  7470  			rts, offs := o.RegisterTypesAndOffsets()
  7471  			for i := range o.Registers {
  7472  				Arch.LoadRegResult(&s, f, rts[i], ssa.ObjRegForAbiReg(o.Registers[i], f.Config), n, offs[i])
  7473  			}
  7474  		}
  7475  
  7476  		pp.Prog(obj.ARET)
  7477  	}
  7478  
  7479  	if inlMarks != nil {
  7480  		hasCall := false
  7481  
  7482  		// We have some inline marks. Try to find other instructions we're
  7483  		// going to emit anyway, and use those instructions instead of the
  7484  		// inline marks.
  7485  		for p := pp.Text; p != nil; p = p.Link {
  7486  			if p.As == obj.ANOP || p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT || p.As == obj.APCALIGN || Arch.LinkArch.Family == sys.Wasm {
  7487  				// Don't use 0-sized instructions as inline marks, because we need
  7488  				// to identify inline mark instructions by pc offset.
  7489  				// (Some of these instructions are sometimes zero-sized, sometimes not.
  7490  				// We must not use anything that even might be zero-sized.)
  7491  				// TODO: are there others?
  7492  				continue
  7493  			}
  7494  			if _, ok := inlMarks[p]; ok {
  7495  				// Don't use inline marks themselves. We don't know
  7496  				// whether they will be zero-sized or not yet.
  7497  				continue
  7498  			}
  7499  			if p.As == obj.ACALL || p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
  7500  				hasCall = true
  7501  			}
  7502  			pos := p.Pos.AtColumn1()
  7503  			s := inlMarksByPos[pos]
  7504  			if len(s) == 0 {
  7505  				continue
  7506  			}
  7507  			for _, m := range s {
  7508  				// We found an instruction with the same source position as
  7509  				// some of the inline marks.
  7510  				// Use this instruction instead.
  7511  				p.Pos = p.Pos.WithIsStmt() // promote position to a statement
  7512  				pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[m])
  7513  				// Make the inline mark a real nop, so it doesn't generate any code.
  7514  				m.As = obj.ANOP
  7515  				m.Pos = src.NoXPos
  7516  				m.From = obj.Addr{}
  7517  				m.To = obj.Addr{}
  7518  			}
  7519  			delete(inlMarksByPos, pos)
  7520  		}
  7521  		// Any unmatched inline marks now need to be added to the inlining tree (and will generate a nop instruction).
  7522  		for _, p := range inlMarkList {
  7523  			if p.As != obj.ANOP {
  7524  				pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[p])
  7525  			}
  7526  		}
  7527  
  7528  		if e.stksize == 0 && !hasCall {
  7529  			// Frameless leaf function. It doesn't need any preamble,
  7530  			// so make sure its first instruction isn't from an inlined callee.
  7531  			// If it is, add a nop at the start of the function with a position
  7532  			// equal to the start of the function.
  7533  			// This ensures that runtime.FuncForPC(uintptr(reflect.ValueOf(fn).Pointer())).Name()
  7534  			// returns the right answer. See issue 58300.
  7535  			for p := pp.Text; p != nil; p = p.Link {
  7536  				if p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT || p.As == obj.ANOP {
  7537  					continue
  7538  				}
  7539  				if base.Ctxt.PosTable.Pos(p.Pos).Base().InliningIndex() >= 0 {
  7540  					// Make a real (not 0-sized) nop.
  7541  					nop := Arch.Ginsnop(pp)
  7542  					nop.Pos = e.curfn.Pos().WithIsStmt()
  7543  
  7544  					// Unfortunately, Ginsnop puts the instruction at the
  7545  					// end of the list. Move it up to just before p.
  7546  
  7547  					// Unlink from the current list.
  7548  					for x := pp.Text; x != nil; x = x.Link {
  7549  						if x.Link == nop {
  7550  							x.Link = nop.Link
  7551  							break
  7552  						}
  7553  					}
  7554  					// Splice in right before p.
  7555  					for x := pp.Text; x != nil; x = x.Link {
  7556  						if x.Link == p {
  7557  							nop.Link = p
  7558  							x.Link = nop
  7559  							break
  7560  						}
  7561  					}
  7562  				}
  7563  				break
  7564  			}
  7565  		}
  7566  	}
  7567  
  7568  	if base.Ctxt.Flag_locationlists {
  7569  		var debugInfo *ssa.FuncDebug
  7570  		debugInfo = e.curfn.DebugInfo.(*ssa.FuncDebug)
  7571  		if e.curfn.ABI == obj.ABIInternal && base.Flag.N != 0 {
  7572  			ssa.BuildFuncDebugNoOptimized(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
  7573  		} else {
  7574  			ssa.BuildFuncDebug(base.Ctxt, f, base.Debug.LocationLists, StackOffset, debugInfo)
  7575  		}
  7576  		bstart := s.bstart
  7577  		idToIdx := make([]int, f.NumBlocks())
  7578  		for i, b := range f.Blocks {
  7579  			idToIdx[b.ID] = i
  7580  		}
  7581  		// Register a callback that will be used later to fill in PCs into location
  7582  		// lists. At the moment, Prog.Pc is a sequence number; it's not a real PC
  7583  		// until after assembly, so the translation needs to be deferred.
  7584  		debugInfo.GetPC = func(b, v ssa.ID) int64 {
  7585  			switch v {
  7586  			case ssa.BlockStart.ID:
  7587  				if b == f.Entry.ID {
  7588  					return 0 // Start at the very beginning, at the assembler-generated prologue.
  7589  					// this should only happen for function args (ssa.OpArg)
  7590  				}
  7591  				return bstart[b].Pc
  7592  			case ssa.BlockEnd.ID:
  7593  				blk := f.Blocks[idToIdx[b]]
  7594  				nv := len(blk.Values)
  7595  				return valueToProgAfter[blk.Values[nv-1].ID].Pc
  7596  			case ssa.FuncEnd.ID:
  7597  				return e.curfn.LSym.Size
  7598  			default:
  7599  				return valueToProgAfter[v].Pc
  7600  			}
  7601  		}
  7602  	}
  7603  
  7604  	// Resolve branches, and relax DefaultStmt into NotStmt
  7605  	for _, br := range s.Branches {
  7606  		br.P.To.SetTarget(s.bstart[br.B.ID])
  7607  		if br.P.Pos.IsStmt() != src.PosIsStmt {
  7608  			br.P.Pos = br.P.Pos.WithNotStmt()
  7609  		} else if v0 := br.B.FirstPossibleStmtValue(); v0 != nil && v0.Pos.Line() == br.P.Pos.Line() && v0.Pos.IsStmt() == src.PosIsStmt {
  7610  			br.P.Pos = br.P.Pos.WithNotStmt()
  7611  		}
  7612  
  7613  	}
  7614  
  7615  	// Resolve jump table destinations.
  7616  	for _, jt := range s.JumpTables {
  7617  		// Convert from *Block targets to *Prog targets.
  7618  		targets := make([]*obj.Prog, len(jt.Succs))
  7619  		for i, e := range jt.Succs {
  7620  			targets[i] = s.bstart[e.Block().ID]
  7621  		}
  7622  		// Add to list of jump tables to be resolved at assembly time.
  7623  		// The assembler converts from *Prog entries to absolute addresses
  7624  		// once it knows instruction byte offsets.
  7625  		fi := pp.CurFunc.LSym.Func()
  7626  		fi.JumpTables = append(fi.JumpTables, obj.JumpTable{Sym: jt.Aux.(*obj.LSym), Targets: targets})
  7627  	}
  7628  
  7629  	if e.log { // spew to stdout
  7630  		filename := ""
  7631  		for p := pp.Text; p != nil; p = p.Link {
  7632  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7633  				filename = p.InnermostFilename()
  7634  				f.Logf("# %s\n", filename)
  7635  			}
  7636  
  7637  			var s string
  7638  			if v, ok := progToValue[p]; ok {
  7639  				s = v.String()
  7640  			} else if b, ok := progToBlock[p]; ok {
  7641  				s = b.String()
  7642  			} else {
  7643  				s = "   " // most value and branch strings are 2-3 characters long
  7644  			}
  7645  			f.Logf(" %-6s\t%.5d (%s)\t%s\n", s, p.Pc, p.InnermostLineNumber(), p.InstructionString())
  7646  		}
  7647  	}
  7648  	if f.HTMLWriter != nil { // spew to ssa.html
  7649  		var buf strings.Builder
  7650  		buf.WriteString("<code>")
  7651  		buf.WriteString("<dl class=\"ssa-gen\">")
  7652  		filename := ""
  7653  		for p := pp.Text; p != nil; p = p.Link {
  7654  			// Don't spam every line with the file name, which is often huge.
  7655  			// Only print changes, and "unknown" is not a change.
  7656  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7657  				filename = p.InnermostFilename()
  7658  				buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7659  				buf.WriteString(html.EscapeString("# " + filename))
  7660  				buf.WriteString("</dd>")
  7661  			}
  7662  
  7663  			buf.WriteString("<dt class=\"ssa-prog-src\">")
  7664  			if v, ok := progToValue[p]; ok {
  7665  				buf.WriteString(v.HTML())
  7666  			} else if b, ok := progToBlock[p]; ok {
  7667  				buf.WriteString("<b>" + b.HTML() + "</b>")
  7668  			}
  7669  			buf.WriteString("</dt>")
  7670  			buf.WriteString("<dd class=\"ssa-prog\">")
  7671  			fmt.Fprintf(&buf, "%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString()))
  7672  			buf.WriteString("</dd>")
  7673  		}
  7674  		buf.WriteString("</dl>")
  7675  		buf.WriteString("</code>")
  7676  		f.HTMLWriter.WriteColumn("genssa", "genssa", "ssa-prog", buf.String())
  7677  	}
  7678  	if ssa.GenssaDump[f.Name] {
  7679  		fi := f.DumpFileForPhase("genssa")
  7680  		if fi != nil {
  7681  
  7682  			// inliningDiffers if any filename changes or if any line number except the innermost (last index) changes.
  7683  			inliningDiffers := func(a, b []src.Pos) bool {
  7684  				if len(a) != len(b) {
  7685  					return true
  7686  				}
  7687  				for i := range a {
  7688  					if a[i].Filename() != b[i].Filename() {
  7689  						return true
  7690  					}
  7691  					if i != len(a)-1 && a[i].Line() != b[i].Line() {
  7692  						return true
  7693  					}
  7694  				}
  7695  				return false
  7696  			}
  7697  
  7698  			var allPosOld []src.Pos
  7699  			var allPos []src.Pos
  7700  
  7701  			for p := pp.Text; p != nil; p = p.Link {
  7702  				if p.Pos.IsKnown() {
  7703  					allPos = allPos[:0]
  7704  					p.Ctxt.AllPos(p.Pos, func(pos src.Pos) { allPos = append(allPos, pos) })
  7705  					if inliningDiffers(allPos, allPosOld) {
  7706  						for _, pos := range allPos {
  7707  							fmt.Fprintf(fi, "# %s:%d\n", pos.Filename(), pos.Line())
  7708  						}
  7709  						allPos, allPosOld = allPosOld, allPos // swap, not copy, so that they do not share slice storage.
  7710  					}
  7711  				}
  7712  
  7713  				var s string
  7714  				if v, ok := progToValue[p]; ok {
  7715  					s = v.String()
  7716  				} else if b, ok := progToBlock[p]; ok {
  7717  					s = b.String()
  7718  				} else {
  7719  					s = "   " // most value and branch strings are 2-3 characters long
  7720  				}
  7721  				fmt.Fprintf(fi, " %-6s\t%.5d %s\t%s\n", s, p.Pc, ssa.StmtString(p.Pos), p.InstructionString())
  7722  			}
  7723  			fi.Close()
  7724  		}
  7725  	}
  7726  
  7727  	defframe(&s, e, f)
  7728  
  7729  	f.HTMLWriter.Close()
  7730  	f.HTMLWriter = nil
  7731  }
  7732  
  7733  func defframe(s *State, e *ssafn, f *ssa.Func) {
  7734  	pp := s.pp
  7735  
  7736  	s.maxarg = types.RoundUp(s.maxarg, e.stkalign)
  7737  	frame := s.maxarg + e.stksize
  7738  	if Arch.PadFrame != nil {
  7739  		frame = Arch.PadFrame(frame)
  7740  	}
  7741  
  7742  	// Fill in argument and frame size.
  7743  	pp.Text.To.Type = obj.TYPE_TEXTSIZE
  7744  	pp.Text.To.Val = int32(types.RoundUp(f.OwnAux.ArgWidth(), int64(types.RegSize)))
  7745  	pp.Text.To.Offset = frame
  7746  
  7747  	p := pp.Text
  7748  
  7749  	// Insert code to spill argument registers if the named slot may be partially
  7750  	// live. That is, the named slot is considered live by liveness analysis,
  7751  	// (because a part of it is live), but we may not spill all parts into the
  7752  	// slot. This can only happen with aggregate-typed arguments that are SSA-able
  7753  	// and not address-taken (for non-SSA-able or address-taken arguments we always
  7754  	// spill upfront).
  7755  	// Note: spilling is unnecessary in the -N/no-optimize case, since all values
  7756  	// will be considered non-SSAable and spilled up front.
  7757  	// TODO(register args) Make liveness more fine-grained to that partial spilling is okay.
  7758  	if f.OwnAux.ABIInfo().InRegistersUsed() != 0 && base.Flag.N == 0 {
  7759  		// First, see if it is already spilled before it may be live. Look for a spill
  7760  		// in the entry block up to the first safepoint.
  7761  		type nameOff struct {
  7762  			n   *ir.Name
  7763  			off int64
  7764  		}
  7765  		partLiveArgsSpilled := make(map[nameOff]bool)
  7766  		for _, v := range f.Entry.Values {
  7767  			if v.Op.IsCall() {
  7768  				break
  7769  			}
  7770  			if v.Op != ssa.OpStoreReg || v.Args[0].Op != ssa.OpArgIntReg {
  7771  				continue
  7772  			}
  7773  			n, off := ssa.AutoVar(v)
  7774  			if n.Class != ir.PPARAM || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] {
  7775  				continue
  7776  			}
  7777  			partLiveArgsSpilled[nameOff{n, off}] = true
  7778  		}
  7779  
  7780  		// Then, insert code to spill registers if not already.
  7781  		for _, a := range f.OwnAux.ABIInfo().InParams() {
  7782  			n := a.Name
  7783  			if n == nil || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] || len(a.Registers) <= 1 {
  7784  				continue
  7785  			}
  7786  			rts, offs := a.RegisterTypesAndOffsets()
  7787  			for i := range a.Registers {
  7788  				if !rts[i].HasPointers() {
  7789  					continue
  7790  				}
  7791  				if partLiveArgsSpilled[nameOff{n, offs[i]}] {
  7792  					continue // already spilled
  7793  				}
  7794  				reg := ssa.ObjRegForAbiReg(a.Registers[i], f.Config)
  7795  				p = Arch.SpillArgReg(pp, p, f, rts[i], reg, n, offs[i])
  7796  			}
  7797  		}
  7798  	}
  7799  
  7800  	// Insert code to zero ambiguously live variables so that the
  7801  	// garbage collector only sees initialized values when it
  7802  	// looks for pointers.
  7803  	var lo, hi int64
  7804  
  7805  	// Opaque state for backend to use. Current backends use it to
  7806  	// keep track of which helper registers have been zeroed.
  7807  	var state uint32
  7808  
  7809  	// Iterate through declarations. Autos are sorted in decreasing
  7810  	// frame offset order.
  7811  	for _, n := range e.curfn.Dcl {
  7812  		if !n.Needzero() {
  7813  			continue
  7814  		}
  7815  		if n.Class != ir.PAUTO {
  7816  			e.Fatalf(n.Pos(), "needzero class %d", n.Class)
  7817  		}
  7818  		if n.Type().Size()%int64(types.PtrSize) != 0 || n.FrameOffset()%int64(types.PtrSize) != 0 || n.Type().Size() == 0 {
  7819  			e.Fatalf(n.Pos(), "var %L has size %d offset %d", n, n.Type().Size(), n.Offset_)
  7820  		}
  7821  
  7822  		if lo != hi && n.FrameOffset()+n.Type().Size() >= lo-int64(2*types.RegSize) {
  7823  			// Merge with range we already have.
  7824  			lo = n.FrameOffset()
  7825  			continue
  7826  		}
  7827  
  7828  		// Zero old range
  7829  		p = Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7830  
  7831  		// Set new range.
  7832  		lo = n.FrameOffset()
  7833  		hi = lo + n.Type().Size()
  7834  	}
  7835  
  7836  	// Zero final range.
  7837  	Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7838  }
  7839  
  7840  // For generating consecutive jump instructions to model a specific branching
  7841  type IndexJump struct {
  7842  	Jump  obj.As
  7843  	Index int
  7844  }
  7845  
  7846  func (s *State) oneJump(b *ssa.Block, jump *IndexJump) {
  7847  	p := s.Br(jump.Jump, b.Succs[jump.Index].Block())
  7848  	p.Pos = b.Pos
  7849  }
  7850  
  7851  // CombJump generates combinational instructions (2 at present) for a block jump,
  7852  // thereby the behaviour of non-standard condition codes could be simulated
  7853  func (s *State) CombJump(b, next *ssa.Block, jumps *[2][2]IndexJump) {
  7854  	switch next {
  7855  	case b.Succs[0].Block():
  7856  		s.oneJump(b, &jumps[0][0])
  7857  		s.oneJump(b, &jumps[0][1])
  7858  	case b.Succs[1].Block():
  7859  		s.oneJump(b, &jumps[1][0])
  7860  		s.oneJump(b, &jumps[1][1])
  7861  	default:
  7862  		var q *obj.Prog
  7863  		if b.Likely != ssa.BranchUnlikely {
  7864  			s.oneJump(b, &jumps[1][0])
  7865  			s.oneJump(b, &jumps[1][1])
  7866  			q = s.Br(obj.AJMP, b.Succs[1].Block())
  7867  		} else {
  7868  			s.oneJump(b, &jumps[0][0])
  7869  			s.oneJump(b, &jumps[0][1])
  7870  			q = s.Br(obj.AJMP, b.Succs[0].Block())
  7871  		}
  7872  		q.Pos = b.Pos
  7873  	}
  7874  }
  7875  
  7876  // AddAux adds the offset in the aux fields (AuxInt and Aux) of v to a.
  7877  func AddAux(a *obj.Addr, v *ssa.Value) {
  7878  	AddAux2(a, v, v.AuxInt)
  7879  }
  7880  func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
  7881  	if a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR {
  7882  		v.Fatalf("bad AddAux addr %v", a)
  7883  	}
  7884  	// add integer offset
  7885  	a.Offset += offset
  7886  
  7887  	// If no additional symbol offset, we're done.
  7888  	if v.Aux == nil {
  7889  		return
  7890  	}
  7891  	// Add symbol's offset from its base register.
  7892  	switch n := v.Aux.(type) {
  7893  	case *ssa.AuxCall:
  7894  		a.Name = obj.NAME_EXTERN
  7895  		a.Sym = n.Fn
  7896  	case *obj.LSym:
  7897  		a.Name = obj.NAME_EXTERN
  7898  		a.Sym = n
  7899  	case *ir.Name:
  7900  		if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7901  			a.Name = obj.NAME_PARAM
  7902  		} else {
  7903  			a.Name = obj.NAME_AUTO
  7904  		}
  7905  		a.Sym = n.Linksym()
  7906  		a.Offset += n.FrameOffset()
  7907  	default:
  7908  		v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
  7909  	}
  7910  }
  7911  
  7912  // extendIndex extends v to a full int width.
  7913  // panic with the given kind if v does not fit in an int (only on 32-bit archs).
  7914  func (s *state) extendIndex(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  7915  	size := idx.Type.Size()
  7916  	if size == s.config.PtrSize {
  7917  		return idx
  7918  	}
  7919  	if size > s.config.PtrSize {
  7920  		// truncate 64-bit indexes on 32-bit pointer archs. Test the
  7921  		// high word and branch to out-of-bounds failure if it is not 0.
  7922  		var lo *ssa.Value
  7923  		if idx.Type.IsSigned() {
  7924  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TINT], idx)
  7925  		} else {
  7926  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TUINT], idx)
  7927  		}
  7928  		if bounded || base.Flag.B != 0 {
  7929  			return lo
  7930  		}
  7931  		bNext := s.f.NewBlock(ssa.BlockPlain)
  7932  		bPanic := s.f.NewBlock(ssa.BlockExit)
  7933  		hi := s.newValue1(ssa.OpInt64Hi, types.Types[types.TUINT32], idx)
  7934  		cmp := s.newValue2(ssa.OpEq32, types.Types[types.TBOOL], hi, s.constInt32(types.Types[types.TUINT32], 0))
  7935  		if !idx.Type.IsSigned() {
  7936  			switch kind {
  7937  			case ssa.BoundsIndex:
  7938  				kind = ssa.BoundsIndexU
  7939  			case ssa.BoundsSliceAlen:
  7940  				kind = ssa.BoundsSliceAlenU
  7941  			case ssa.BoundsSliceAcap:
  7942  				kind = ssa.BoundsSliceAcapU
  7943  			case ssa.BoundsSliceB:
  7944  				kind = ssa.BoundsSliceBU
  7945  			case ssa.BoundsSlice3Alen:
  7946  				kind = ssa.BoundsSlice3AlenU
  7947  			case ssa.BoundsSlice3Acap:
  7948  				kind = ssa.BoundsSlice3AcapU
  7949  			case ssa.BoundsSlice3B:
  7950  				kind = ssa.BoundsSlice3BU
  7951  			case ssa.BoundsSlice3C:
  7952  				kind = ssa.BoundsSlice3CU
  7953  			}
  7954  		}
  7955  		b := s.endBlock()
  7956  		b.Kind = ssa.BlockIf
  7957  		b.SetControl(cmp)
  7958  		b.Likely = ssa.BranchLikely
  7959  		b.AddEdgeTo(bNext)
  7960  		b.AddEdgeTo(bPanic)
  7961  
  7962  		s.startBlock(bPanic)
  7963  		mem := s.newValue4I(ssa.OpPanicExtend, types.TypeMem, int64(kind), hi, lo, len, s.mem())
  7964  		s.endBlock().SetControl(mem)
  7965  		s.startBlock(bNext)
  7966  
  7967  		return lo
  7968  	}
  7969  
  7970  	// Extend value to the required size
  7971  	var op ssa.Op
  7972  	if idx.Type.IsSigned() {
  7973  		switch 10*size + s.config.PtrSize {
  7974  		case 14:
  7975  			op = ssa.OpSignExt8to32
  7976  		case 18:
  7977  			op = ssa.OpSignExt8to64
  7978  		case 24:
  7979  			op = ssa.OpSignExt16to32
  7980  		case 28:
  7981  			op = ssa.OpSignExt16to64
  7982  		case 48:
  7983  			op = ssa.OpSignExt32to64
  7984  		default:
  7985  			s.Fatalf("bad signed index extension %s", idx.Type)
  7986  		}
  7987  	} else {
  7988  		switch 10*size + s.config.PtrSize {
  7989  		case 14:
  7990  			op = ssa.OpZeroExt8to32
  7991  		case 18:
  7992  			op = ssa.OpZeroExt8to64
  7993  		case 24:
  7994  			op = ssa.OpZeroExt16to32
  7995  		case 28:
  7996  			op = ssa.OpZeroExt16to64
  7997  		case 48:
  7998  			op = ssa.OpZeroExt32to64
  7999  		default:
  8000  			s.Fatalf("bad unsigned index extension %s", idx.Type)
  8001  		}
  8002  	}
  8003  	return s.newValue1(op, types.Types[types.TINT], idx)
  8004  }
  8005  
  8006  // CheckLoweredPhi checks that regalloc and stackalloc correctly handled phi values.
  8007  // Called during ssaGenValue.
  8008  func CheckLoweredPhi(v *ssa.Value) {
  8009  	if v.Op != ssa.OpPhi {
  8010  		v.Fatalf("CheckLoweredPhi called with non-phi value: %v", v.LongString())
  8011  	}
  8012  	if v.Type.IsMemory() {
  8013  		return
  8014  	}
  8015  	f := v.Block.Func
  8016  	loc := f.RegAlloc[v.ID]
  8017  	for _, a := range v.Args {
  8018  		if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
  8019  			v.Fatalf("phi arg at different location than phi: %v @ %s, but arg %v @ %s\n%s\n", v, loc, a, aloc, v.Block.Func)
  8020  		}
  8021  	}
  8022  }
  8023  
  8024  // CheckLoweredGetClosurePtr checks that v is the first instruction in the function's entry block,
  8025  // except for incoming in-register arguments.
  8026  // The output of LoweredGetClosurePtr is generally hardwired to the correct register.
  8027  // That register contains the closure pointer on closure entry.
  8028  func CheckLoweredGetClosurePtr(v *ssa.Value) {
  8029  	entry := v.Block.Func.Entry
  8030  	if entry != v.Block {
  8031  		base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  8032  	}
  8033  	for _, w := range entry.Values {
  8034  		if w == v {
  8035  			break
  8036  		}
  8037  		switch w.Op {
  8038  		case ssa.OpArgIntReg, ssa.OpArgFloatReg:
  8039  			// okay
  8040  		default:
  8041  			base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  8042  		}
  8043  	}
  8044  }
  8045  
  8046  // CheckArgReg ensures that v is in the function's entry block.
  8047  func CheckArgReg(v *ssa.Value) {
  8048  	entry := v.Block.Func.Entry
  8049  	if entry != v.Block {
  8050  		base.Fatalf("in %s, badly placed ArgIReg or ArgFReg: %v %v", v.Block.Func.Name, v.Block, v)
  8051  	}
  8052  }
  8053  
  8054  func AddrAuto(a *obj.Addr, v *ssa.Value) {
  8055  	n, off := ssa.AutoVar(v)
  8056  	a.Type = obj.TYPE_MEM
  8057  	a.Sym = n.Linksym()
  8058  	a.Reg = int16(Arch.REGSP)
  8059  	a.Offset = n.FrameOffset() + off
  8060  	if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  8061  		a.Name = obj.NAME_PARAM
  8062  	} else {
  8063  		a.Name = obj.NAME_AUTO
  8064  	}
  8065  }
  8066  
  8067  // Call returns a new CALL instruction for the SSA value v.
  8068  // It uses PrepareCall to prepare the call.
  8069  func (s *State) Call(v *ssa.Value) *obj.Prog {
  8070  	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness fo the call comes from ssaGenState
  8071  	s.PrepareCall(v)
  8072  
  8073  	p := s.Prog(obj.ACALL)
  8074  	if pPosIsStmt == src.PosIsStmt {
  8075  		p.Pos = v.Pos.WithIsStmt()
  8076  	} else {
  8077  		p.Pos = v.Pos.WithNotStmt()
  8078  	}
  8079  	if sym, ok := v.Aux.(*ssa.AuxCall); ok && sym.Fn != nil {
  8080  		p.To.Type = obj.TYPE_MEM
  8081  		p.To.Name = obj.NAME_EXTERN
  8082  		p.To.Sym = sym.Fn
  8083  	} else {
  8084  		// TODO(mdempsky): Can these differences be eliminated?
  8085  		switch Arch.LinkArch.Family {
  8086  		case sys.AMD64, sys.I386, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm:
  8087  			p.To.Type = obj.TYPE_REG
  8088  		case sys.ARM, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64:
  8089  			p.To.Type = obj.TYPE_MEM
  8090  		default:
  8091  			base.Fatalf("unknown indirect call family")
  8092  		}
  8093  		p.To.Reg = v.Args[0].Reg()
  8094  	}
  8095  	return p
  8096  }
  8097  
  8098  // TailCall returns a new tail call instruction for the SSA value v.
  8099  // It is like Call, but for a tail call.
  8100  func (s *State) TailCall(v *ssa.Value) *obj.Prog {
  8101  	p := s.Call(v)
  8102  	p.As = obj.ARET
  8103  	return p
  8104  }
  8105  
  8106  // PrepareCall prepares to emit a CALL instruction for v and does call-related bookkeeping.
  8107  // It must be called immediately before emitting the actual CALL instruction,
  8108  // since it emits PCDATA for the stack map at the call (calls are safe points).
  8109  func (s *State) PrepareCall(v *ssa.Value) {
  8110  	idx := s.livenessMap.Get(v)
  8111  	if !idx.StackMapValid() {
  8112  		// See Liveness.hasStackMap.
  8113  		if sym, ok := v.Aux.(*ssa.AuxCall); !ok || !(sym.Fn == ir.Syms.WBZero || sym.Fn == ir.Syms.WBMove) {
  8114  			base.Fatalf("missing stack map index for %v", v.LongString())
  8115  		}
  8116  	}
  8117  
  8118  	call, ok := v.Aux.(*ssa.AuxCall)
  8119  
  8120  	if ok {
  8121  		// Record call graph information for nowritebarrierrec
  8122  		// analysis.
  8123  		if nowritebarrierrecCheck != nil {
  8124  			nowritebarrierrecCheck.recordCall(s.pp.CurFunc, call.Fn, v.Pos)
  8125  		}
  8126  	}
  8127  
  8128  	if s.maxarg < v.AuxInt {
  8129  		s.maxarg = v.AuxInt
  8130  	}
  8131  }
  8132  
  8133  // UseArgs records the fact that an instruction needs a certain amount of
  8134  // callee args space for its use.
  8135  func (s *State) UseArgs(n int64) {
  8136  	if s.maxarg < n {
  8137  		s.maxarg = n
  8138  	}
  8139  }
  8140  
  8141  // fieldIdx finds the index of the field referred to by the ODOT node n.
  8142  func fieldIdx(n *ir.SelectorExpr) int {
  8143  	t := n.X.Type()
  8144  	if !t.IsStruct() {
  8145  		panic("ODOT's LHS is not a struct")
  8146  	}
  8147  
  8148  	for i, f := range t.Fields() {
  8149  		if f.Sym == n.Sel {
  8150  			if f.Offset != n.Offset() {
  8151  				panic("field offset doesn't match")
  8152  			}
  8153  			return i
  8154  		}
  8155  	}
  8156  	panic(fmt.Sprintf("can't find field in expr %v\n", n))
  8157  
  8158  	// TODO: keep the result of this function somewhere in the ODOT Node
  8159  	// so we don't have to recompute it each time we need it.
  8160  }
  8161  
  8162  // ssafn holds frontend information about a function that the backend is processing.
  8163  // It also exports a bunch of compiler services for the ssa backend.
  8164  type ssafn struct {
  8165  	curfn      *ir.Func
  8166  	strings    map[string]*obj.LSym // map from constant string to data symbols
  8167  	stksize    int64                // stack size for current frame
  8168  	stkptrsize int64                // prefix of stack containing pointers
  8169  
  8170  	// alignment for current frame.
  8171  	// NOTE: when stkalign > PtrSize, currently this only ensures the offsets of
  8172  	// objects in the stack frame are aligned. The stack pointer is still aligned
  8173  	// only PtrSize.
  8174  	stkalign int64
  8175  
  8176  	log bool // print ssa debug to the stdout
  8177  }
  8178  
  8179  // StringData returns a symbol which
  8180  // is the data component of a global string constant containing s.
  8181  func (e *ssafn) StringData(s string) *obj.LSym {
  8182  	if aux, ok := e.strings[s]; ok {
  8183  		return aux
  8184  	}
  8185  	if e.strings == nil {
  8186  		e.strings = make(map[string]*obj.LSym)
  8187  	}
  8188  	data := staticdata.StringSym(e.curfn.Pos(), s)
  8189  	e.strings[s] = data
  8190  	return data
  8191  }
  8192  
  8193  // SplitSlot returns a slot representing the data of parent starting at offset.
  8194  func (e *ssafn) SplitSlot(parent *ssa.LocalSlot, suffix string, offset int64, t *types.Type) ssa.LocalSlot {
  8195  	node := parent.N
  8196  
  8197  	if node.Class != ir.PAUTO || node.Addrtaken() {
  8198  		// addressed things and non-autos retain their parents (i.e., cannot truly be split)
  8199  		return ssa.LocalSlot{N: node, Type: t, Off: parent.Off + offset}
  8200  	}
  8201  
  8202  	sym := &types.Sym{Name: node.Sym().Name + suffix, Pkg: types.LocalPkg}
  8203  	n := e.curfn.NewLocal(parent.N.Pos(), sym, t)
  8204  	n.SetUsed(true)
  8205  	n.SetEsc(ir.EscNever)
  8206  	types.CalcSize(t)
  8207  	return ssa.LocalSlot{N: n, Type: t, Off: 0, SplitOf: parent, SplitOffset: offset}
  8208  }
  8209  
  8210  // Logf logs a message from the compiler.
  8211  func (e *ssafn) Logf(msg string, args ...interface{}) {
  8212  	if e.log {
  8213  		fmt.Printf(msg, args...)
  8214  	}
  8215  }
  8216  
  8217  func (e *ssafn) Log() bool {
  8218  	return e.log
  8219  }
  8220  
  8221  // Fatalf reports a compiler error and exits.
  8222  func (e *ssafn) Fatalf(pos src.XPos, msg string, args ...interface{}) {
  8223  	base.Pos = pos
  8224  	nargs := append([]interface{}{ir.FuncName(e.curfn)}, args...)
  8225  	base.Fatalf("'%s': "+msg, nargs...)
  8226  }
  8227  
  8228  // Warnl reports a "warning", which is usually flag-triggered
  8229  // logging output for the benefit of tests.
  8230  func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...interface{}) {
  8231  	base.WarnfAt(pos, fmt_, args...)
  8232  }
  8233  
  8234  func (e *ssafn) Debug_checknil() bool {
  8235  	return base.Debug.Nil != 0
  8236  }
  8237  
  8238  func (e *ssafn) UseWriteBarrier() bool {
  8239  	return base.Flag.WB
  8240  }
  8241  
  8242  func (e *ssafn) Syslook(name string) *obj.LSym {
  8243  	switch name {
  8244  	case "goschedguarded":
  8245  		return ir.Syms.Goschedguarded
  8246  	case "writeBarrier":
  8247  		return ir.Syms.WriteBarrier
  8248  	case "wbZero":
  8249  		return ir.Syms.WBZero
  8250  	case "wbMove":
  8251  		return ir.Syms.WBMove
  8252  	case "cgoCheckMemmove":
  8253  		return ir.Syms.CgoCheckMemmove
  8254  	case "cgoCheckPtrWrite":
  8255  		return ir.Syms.CgoCheckPtrWrite
  8256  	}
  8257  	e.Fatalf(src.NoXPos, "unknown Syslook func %v", name)
  8258  	return nil
  8259  }
  8260  
  8261  func (e *ssafn) Func() *ir.Func {
  8262  	return e.curfn
  8263  }
  8264  
  8265  func clobberBase(n ir.Node) ir.Node {
  8266  	if n.Op() == ir.ODOT {
  8267  		n := n.(*ir.SelectorExpr)
  8268  		if n.X.Type().NumFields() == 1 {
  8269  			return clobberBase(n.X)
  8270  		}
  8271  	}
  8272  	if n.Op() == ir.OINDEX {
  8273  		n := n.(*ir.IndexExpr)
  8274  		if n.X.Type().IsArray() && n.X.Type().NumElem() == 1 {
  8275  			return clobberBase(n.X)
  8276  		}
  8277  	}
  8278  	return n
  8279  }
  8280  
  8281  // callTargetLSym returns the correct LSym to call 'callee' using its ABI.
  8282  func callTargetLSym(callee *ir.Name) *obj.LSym {
  8283  	if callee.Func == nil {
  8284  		// TODO(austin): This happens in case of interface method I.M from imported package.
  8285  		// It's ABIInternal, and would be better if callee.Func was never nil and we didn't
  8286  		// need this case.
  8287  		return callee.Linksym()
  8288  	}
  8289  
  8290  	return callee.LinksymABI(callee.Func.ABI)
  8291  }
  8292  
  8293  func min8(a, b int8) int8 {
  8294  	if a < b {
  8295  		return a
  8296  	}
  8297  	return b
  8298  }
  8299  
  8300  func max8(a, b int8) int8 {
  8301  	if a > b {
  8302  		return a
  8303  	}
  8304  	return b
  8305  }
  8306  
  8307  // deferStructFnField is the field index of _defer.fn.
  8308  const deferStructFnField = 4
  8309  
  8310  var deferType *types.Type
  8311  
  8312  // deferstruct returns a type interchangeable with runtime._defer.
  8313  // Make sure this stays in sync with runtime/runtime2.go:_defer.
  8314  func deferstruct() *types.Type {
  8315  	if deferType != nil {
  8316  		return deferType
  8317  	}
  8318  
  8319  	makefield := func(name string, t *types.Type) *types.Field {
  8320  		sym := (*types.Pkg)(nil).Lookup(name)
  8321  		return types.NewField(src.NoXPos, sym, t)
  8322  	}
  8323  
  8324  	fields := []*types.Field{
  8325  		makefield("heap", types.Types[types.TBOOL]),
  8326  		makefield("rangefunc", types.Types[types.TBOOL]),
  8327  		makefield("sp", types.Types[types.TUINTPTR]),
  8328  		makefield("pc", types.Types[types.TUINTPTR]),
  8329  		// Note: the types here don't really matter. Defer structures
  8330  		// are always scanned explicitly during stack copying and GC,
  8331  		// so we make them uintptr type even though they are real pointers.
  8332  		makefield("fn", types.Types[types.TUINTPTR]),
  8333  		makefield("link", types.Types[types.TUINTPTR]),
  8334  		makefield("head", types.Types[types.TUINTPTR]),
  8335  	}
  8336  	if name := fields[deferStructFnField].Sym.Name; name != "fn" {
  8337  		base.Fatalf("deferStructFnField is %q, not fn", name)
  8338  	}
  8339  
  8340  	n := ir.NewDeclNameAt(src.NoXPos, ir.OTYPE, ir.Pkgs.Runtime.Lookup("_defer"))
  8341  	typ := types.NewNamed(n)
  8342  	n.SetType(typ)
  8343  	n.SetTypecheck(1)
  8344  
  8345  	// build struct holding the above fields
  8346  	typ.SetUnderlying(types.NewStruct(fields))
  8347  	types.CalcStructSize(typ)
  8348  
  8349  	deferType = typ
  8350  	return typ
  8351  }
  8352  
  8353  // SpillSlotAddr uses LocalSlot information to initialize an obj.Addr
  8354  // The resulting addr is used in a non-standard context -- in the prologue
  8355  // of a function, before the frame has been constructed, so the standard
  8356  // addressing for the parameters will be wrong.
  8357  func SpillSlotAddr(spill ssa.Spill, baseReg int16, extraOffset int64) obj.Addr {
  8358  	return obj.Addr{
  8359  		Name:   obj.NAME_NONE,
  8360  		Type:   obj.TYPE_MEM,
  8361  		Reg:    baseReg,
  8362  		Offset: spill.Offset + extraOffset,
  8363  	}
  8364  }
  8365  
  8366  var (
  8367  	BoundsCheckFunc [ssa.BoundsKindCount]*obj.LSym
  8368  	ExtendCheckFunc [ssa.BoundsKindCount]*obj.LSym
  8369  )
  8370