// Copyright 2015 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package ssa import ( "cmd/compile/internal/ir" "cmd/internal/obj/s390x" "math" "math/bits" ) // checkFunc checks invariants of f. func checkFunc(f *Func) { blockMark := make([]bool, f.NumBlocks()) valueMark := make([]bool, f.NumValues()) for _, b := range f.Blocks { if blockMark[b.ID] { f.Fatalf("block %s appears twice in %s!", b, f.Name) } blockMark[b.ID] = true if b.Func != f { f.Fatalf("%s.Func=%s, want %s", b, b.Func.Name, f.Name) } for i, e := range b.Preds { if se := e.b.Succs[e.i]; se.b != b || se.i != i { f.Fatalf("block pred/succ not crosslinked correctly %d:%s %d:%s", i, b, se.i, se.b) } } for i, e := range b.Succs { if pe := e.b.Preds[e.i]; pe.b != b || pe.i != i { f.Fatalf("block succ/pred not crosslinked correctly %d:%s %d:%s", i, b, pe.i, pe.b) } } switch b.Kind { case BlockExit: if len(b.Succs) != 0 { f.Fatalf("exit block %s has successors", b) } if b.NumControls() != 1 { f.Fatalf("exit block %s has no control value", b) } if !b.Controls[0].Type.IsMemory() { f.Fatalf("exit block %s has non-memory control value %s", b, b.Controls[0].LongString()) } case BlockRet: if len(b.Succs) != 0 { f.Fatalf("ret block %s has successors", b) } if b.NumControls() != 1 { f.Fatalf("ret block %s has nil control", b) } if !b.Controls[0].Type.IsMemory() { f.Fatalf("ret block %s has non-memory control value %s", b, b.Controls[0].LongString()) } case BlockRetJmp: if len(b.Succs) != 0 { f.Fatalf("retjmp block %s len(Succs)==%d, want 0", b, len(b.Succs)) } if b.NumControls() != 1 { f.Fatalf("retjmp block %s has nil control", b) } if !b.Controls[0].Type.IsMemory() { f.Fatalf("retjmp block %s has non-memory control value %s", b, b.Controls[0].LongString()) } case BlockPlain: if len(b.Succs) != 1 { f.Fatalf("plain block %s len(Succs)==%d, want 1", b, len(b.Succs)) } if b.NumControls() != 0 { f.Fatalf("plain block %s has non-nil control %s", b, b.Controls[0].LongString()) } case BlockIf: if len(b.Succs) != 2 { f.Fatalf("if block %s len(Succs)==%d, want 2", b, len(b.Succs)) } if b.NumControls() != 1 { f.Fatalf("if block %s has no control value", b) } if !b.Controls[0].Type.IsBoolean() { f.Fatalf("if block %s has non-bool control value %s", b, b.Controls[0].LongString()) } case BlockDefer: if len(b.Succs) != 2 { f.Fatalf("defer block %s len(Succs)==%d, want 2", b, len(b.Succs)) } if b.NumControls() != 1 { f.Fatalf("defer block %s has no control value", b) } if !b.Controls[0].Type.IsMemory() { f.Fatalf("defer block %s has non-memory control value %s", b, b.Controls[0].LongString()) } case BlockFirst: if len(b.Succs) != 2 { f.Fatalf("plain/dead block %s len(Succs)==%d, want 2", b, len(b.Succs)) } if b.NumControls() != 0 { f.Fatalf("plain/dead block %s has a control value", b) } case BlockJumpTable: if b.NumControls() != 1 { f.Fatalf("jumpTable block %s has no control value", b) } } if len(b.Succs) != 2 && b.Likely != BranchUnknown { f.Fatalf("likeliness prediction %d for block %s with %d successors", b.Likely, b, len(b.Succs)) } for _, v := range b.Values { // Check to make sure argument count makes sense (argLen of -1 indicates // variable length args) nArgs := opcodeTable[v.Op].argLen if nArgs != -1 && int32(len(v.Args)) != nArgs { f.Fatalf("value %s has %d args, expected %d", v.LongString(), len(v.Args), nArgs) } // Check to make sure aux values make sense. canHaveAux := false canHaveAuxInt := false // TODO: enforce types of Aux in this switch (like auxString does below) switch opcodeTable[v.Op].auxType { case auxNone: case auxBool: if v.AuxInt < 0 || v.AuxInt > 1 { f.Fatalf("bad bool AuxInt value for %v", v) } canHaveAuxInt = true case auxInt8: if v.AuxInt != int64(int8(v.AuxInt)) { f.Fatalf("bad int8 AuxInt value for %v", v) } canHaveAuxInt = true case auxInt16: if v.AuxInt != int64(int16(v.AuxInt)) { f.Fatalf("bad int16 AuxInt value for %v", v) } canHaveAuxInt = true case auxInt32: if v.AuxInt != int64(int32(v.AuxInt)) { f.Fatalf("bad int32 AuxInt value for %v", v) } canHaveAuxInt = true case auxInt64, auxARM64BitField: canHaveAuxInt = true case auxInt128: // AuxInt must be zero, so leave canHaveAuxInt set to false. case auxUInt8: if v.AuxInt != int64(uint8(v.AuxInt)) { f.Fatalf("bad uint8 AuxInt value for %v", v) } canHaveAuxInt = true case auxFloat32: canHaveAuxInt = true if math.IsNaN(v.AuxFloat()) { f.Fatalf("value %v has an AuxInt that encodes a NaN", v) } if !isExactFloat32(v.AuxFloat()) { f.Fatalf("value %v has an AuxInt value that is not an exact float32", v) } case auxFloat64: canHaveAuxInt = true if math.IsNaN(v.AuxFloat()) { f.Fatalf("value %v has an AuxInt that encodes a NaN", v) } case auxString: if _, ok := v.Aux.(stringAux); !ok { f.Fatalf("value %v has Aux type %T, want string", v, v.Aux) } canHaveAux = true case auxCallOff: canHaveAuxInt = true fallthrough case auxCall: if ac, ok := v.Aux.(*AuxCall); ok { if v.Op == OpStaticCall && ac.Fn == nil { f.Fatalf("value %v has *AuxCall with nil Fn", v) } } else { f.Fatalf("value %v has Aux type %T, want *AuxCall", v, v.Aux) } canHaveAux = true case auxNameOffsetInt8: if _, ok := v.Aux.(*AuxNameOffset); !ok { f.Fatalf("value %v has Aux type %T, want *AuxNameOffset", v, v.Aux) } canHaveAux = true canHaveAuxInt = true case auxSym, auxTyp: canHaveAux = true case auxSymOff, auxSymValAndOff, auxTypSize: canHaveAuxInt = true canHaveAux = true case auxCCop: if opcodeTable[Op(v.AuxInt)].name == "OpInvalid" { f.Fatalf("value %v has an AuxInt value that is a valid opcode", v) } canHaveAuxInt = true case auxS390XCCMask: if _, ok := v.Aux.(s390x.CCMask); !ok { f.Fatalf("bad type %T for S390XCCMask in %v", v.Aux, v) } canHaveAux = true case auxS390XRotateParams: if _, ok := v.Aux.(s390x.RotateParams); !ok { f.Fatalf("bad type %T for S390XRotateParams in %v", v.Aux, v) } canHaveAux = true case auxFlagConstant: if v.AuxInt < 0 || v.AuxInt > 15 { f.Fatalf("bad FlagConstant AuxInt value for %v", v) } canHaveAuxInt = true default: f.Fatalf("unknown aux type for %s", v.Op) } if !canHaveAux && v.Aux != nil { f.Fatalf("value %s has an Aux value %v but shouldn't", v.LongString(), v.Aux) } if !canHaveAuxInt && v.AuxInt != 0 { f.Fatalf("value %s has an AuxInt value %d but shouldn't", v.LongString(), v.AuxInt) } for i, arg := range v.Args { if arg == nil { f.Fatalf("value %s has nil arg", v.LongString()) } if v.Op != OpPhi { // For non-Phi ops, memory args must be last, if present if arg.Type.IsMemory() && i != len(v.Args)-1 { f.Fatalf("value %s has non-final memory arg (%d < %d)", v.LongString(), i, len(v.Args)-1) } } } if valueMark[v.ID] { f.Fatalf("value %s appears twice!", v.LongString()) } valueMark[v.ID] = true if v.Block != b { f.Fatalf("%s.block != %s", v, b) } if v.Op == OpPhi && len(v.Args) != len(b.Preds) { f.Fatalf("phi length %s does not match pred length %d for block %s", v.LongString(), len(b.Preds), b) } if v.Op == OpAddr { if len(v.Args) == 0 { f.Fatalf("no args for OpAddr %s", v.LongString()) } if v.Args[0].Op != OpSB { f.Fatalf("bad arg to OpAddr %v", v) } } if v.Op == OpLocalAddr { if len(v.Args) != 2 { f.Fatalf("wrong # of args for OpLocalAddr %s", v.LongString()) } if v.Args[0].Op != OpSP { f.Fatalf("bad arg 0 to OpLocalAddr %v", v) } if !v.Args[1].Type.IsMemory() { f.Fatalf("bad arg 1 to OpLocalAddr %v", v) } } if f.RegAlloc != nil && f.Config.SoftFloat && v.Type.IsFloat() { f.Fatalf("unexpected floating-point type %v", v.LongString()) } // Check types. // TODO: more type checks? switch c := f.Config; v.Op { case OpSP, OpSB: if v.Type != c.Types.Uintptr { f.Fatalf("bad %s type: want uintptr, have %s", v.Op, v.Type.String()) } case OpStringLen: if v.Type != c.Types.Int { f.Fatalf("bad %s type: want int, have %s", v.Op, v.Type.String()) } case OpLoad: if !v.Args[1].Type.IsMemory() { f.Fatalf("bad arg 1 type to %s: want mem, have %s", v.Op, v.Args[1].Type.String()) } case OpStore: if !v.Type.IsMemory() { f.Fatalf("bad %s type: want mem, have %s", v.Op, v.Type.String()) } if !v.Args[2].Type.IsMemory() { f.Fatalf("bad arg 2 type to %s: want mem, have %s", v.Op, v.Args[2].Type.String()) } case OpCondSelect: if !v.Args[2].Type.IsBoolean() { f.Fatalf("bad arg 2 type to %s: want boolean, have %s", v.Op, v.Args[2].Type.String()) } case OpAddPtr: if !v.Args[0].Type.IsPtrShaped() && v.Args[0].Type != c.Types.Uintptr { f.Fatalf("bad arg 0 type to %s: want ptr, have %s", v.Op, v.Args[0].LongString()) } if !v.Args[1].Type.IsInteger() { f.Fatalf("bad arg 1 type to %s: want integer, have %s", v.Op, v.Args[1].LongString()) } case OpVarDef: if !v.Aux.(*ir.Name).Type().HasPointers() { f.Fatalf("vardef must have pointer type %s", v.Aux.(*ir.Name).Type().String()) } case OpNilCheck: // nil checks have pointer type before scheduling, and // void type after scheduling. if f.scheduled { if v.Uses != 0 { f.Fatalf("nilcheck must have 0 uses %s", v.Uses) } if !v.Type.IsVoid() { f.Fatalf("nilcheck must have void type %s", v.Type.String()) } } else { if !v.Type.IsPtrShaped() && !v.Type.IsUintptr() { f.Fatalf("nilcheck must have pointer type %s", v.Type.String()) } } if !v.Args[0].Type.IsPtrShaped() && !v.Args[0].Type.IsUintptr() { f.Fatalf("nilcheck must have argument of pointer type %s", v.Args[0].Type.String()) } if !v.Args[1].Type.IsMemory() { f.Fatalf("bad arg 1 type to %s: want mem, have %s", v.Op, v.Args[1].Type.String()) } } // TODO: check for cycles in values } } // Check to make sure all Blocks referenced are in the function. if !blockMark[f.Entry.ID] { f.Fatalf("entry block %v is missing", f.Entry) } for _, b := range f.Blocks { for _, c := range b.Preds { if !blockMark[c.b.ID] { f.Fatalf("predecessor block %v for %v is missing", c, b) } } for _, c := range b.Succs { if !blockMark[c.b.ID] { f.Fatalf("successor block %v for %v is missing", c, b) } } } if len(f.Entry.Preds) > 0 { f.Fatalf("entry block %s of %s has predecessor(s) %v", f.Entry, f.Name, f.Entry.Preds) } // Check to make sure all Values referenced are in the function. for _, b := range f.Blocks { for _, v := range b.Values { for i, a := range v.Args { if !valueMark[a.ID] { f.Fatalf("%v, arg %d of %s, is missing", a, i, v.LongString()) } } } for _, c := range b.ControlValues() { if !valueMark[c.ID] { f.Fatalf("control value for %s is missing: %v", b, c) } } } for b := f.freeBlocks; b != nil; b = b.succstorage[0].b { if blockMark[b.ID] { f.Fatalf("used block b%d in free list", b.ID) } } for v := f.freeValues; v != nil; v = v.argstorage[0] { if valueMark[v.ID] { f.Fatalf("used value v%d in free list", v.ID) } } // Check to make sure all args dominate uses. if f.RegAlloc == nil { // Note: regalloc introduces non-dominating args. // See TODO in regalloc.go. sdom := f.Sdom() for _, b := range f.Blocks { for _, v := range b.Values { for i, arg := range v.Args { x := arg.Block y := b if v.Op == OpPhi { y = b.Preds[i].b } if !domCheck(f, sdom, x, y) { f.Fatalf("arg %d of value %s does not dominate, arg=%s", i, v.LongString(), arg.LongString()) } } } for _, c := range b.ControlValues() { if !domCheck(f, sdom, c.Block, b) { f.Fatalf("control value %s for %s doesn't dominate", c, b) } } } } // Check loop construction if f.RegAlloc == nil && f.pass != nil { // non-nil pass allows better-targeted debug printing ln := f.loopnest() if !ln.hasIrreducible { po := f.postorder() // use po to avoid unreachable blocks. for _, b := range po { for _, s := range b.Succs { bb := s.Block() if ln.b2l[b.ID] == nil && ln.b2l[bb.ID] != nil && bb != ln.b2l[bb.ID].header { f.Fatalf("block %s not in loop branches to non-header block %s in loop", b.String(), bb.String()) } if ln.b2l[b.ID] != nil && ln.b2l[bb.ID] != nil && bb != ln.b2l[bb.ID].header && !ln.b2l[b.ID].isWithinOrEq(ln.b2l[bb.ID]) { f.Fatalf("block %s in loop branches to non-header block %s in non-containing loop", b.String(), bb.String()) } } } } } // Check use counts uses := make([]int32, f.NumValues()) for _, b := range f.Blocks { for _, v := range b.Values { for _, a := range v.Args { uses[a.ID]++ } } for _, c := range b.ControlValues() { uses[c.ID]++ } } for _, b := range f.Blocks { for _, v := range b.Values { if v.Uses != uses[v.ID] { f.Fatalf("%s has %d uses, but has Uses=%d", v, uses[v.ID], v.Uses) } } } memCheck(f) } func memCheck(f *Func) { // Check that if a tuple has a memory type, it is second. for _, b := range f.Blocks { for _, v := range b.Values { if v.Type.IsTuple() && v.Type.FieldType(0).IsMemory() { f.Fatalf("memory is first in a tuple: %s\n", v.LongString()) } } } // Single live memory checks. // These checks only work if there are no memory copies. // (Memory copies introduce ambiguity about which mem value is really live. // probably fixable, but it's easier to avoid the problem.) // For the same reason, disable this check if some memory ops are unused. for _, b := range f.Blocks { for _, v := range b.Values { if (v.Op == OpCopy || v.Uses == 0) && v.Type.IsMemory() { return } } if b != f.Entry && len(b.Preds) == 0 { return } } // Compute live memory at the end of each block. lastmem := make([]*Value, f.NumBlocks()) ss := newSparseSet(f.NumValues()) for _, b := range f.Blocks { // Mark overwritten memory values. Those are args of other // ops that generate memory values. ss.clear() for _, v := range b.Values { if v.Op == OpPhi || !v.Type.IsMemory() { continue } if m := v.MemoryArg(); m != nil { ss.add(m.ID) } } // There should be at most one remaining unoverwritten memory value. for _, v := range b.Values { if !v.Type.IsMemory() { continue } if ss.contains(v.ID) { continue } if lastmem[b.ID] != nil { f.Fatalf("two live memory values in %s: %s and %s", b, lastmem[b.ID], v) } lastmem[b.ID] = v } // If there is no remaining memory value, that means there was no memory update. // Take any memory arg. if lastmem[b.ID] == nil { for _, v := range b.Values { if v.Op == OpPhi { continue } m := v.MemoryArg() if m == nil { continue } if lastmem[b.ID] != nil && lastmem[b.ID] != m { f.Fatalf("two live memory values in %s: %s and %s", b, lastmem[b.ID], m) } lastmem[b.ID] = m } } } // Propagate last live memory through storeless blocks. for { changed := false for _, b := range f.Blocks { if lastmem[b.ID] != nil { continue } for _, e := range b.Preds { p := e.b if lastmem[p.ID] != nil { lastmem[b.ID] = lastmem[p.ID] changed = true break } } } if !changed { break } } // Check merge points. for _, b := range f.Blocks { for _, v := range b.Values { if v.Op == OpPhi && v.Type.IsMemory() { for i, a := range v.Args { if a != lastmem[b.Preds[i].b.ID] { f.Fatalf("inconsistent memory phi %s %d %s %s", v.LongString(), i, a, lastmem[b.Preds[i].b.ID]) } } } } } // Check that only one memory is live at any point. if f.scheduled { for _, b := range f.Blocks { var mem *Value // the current live memory in the block for _, v := range b.Values { if v.Op == OpPhi { if v.Type.IsMemory() { mem = v } continue } if mem == nil && len(b.Preds) > 0 { // If no mem phi, take mem of any predecessor. mem = lastmem[b.Preds[0].b.ID] } for _, a := range v.Args { if a.Type.IsMemory() && a != mem { f.Fatalf("two live mems @ %s: %s and %s", v, mem, a) } } if v.Type.IsMemory() { mem = v } } } } // Check that after scheduling, phis are always first in the block. if f.scheduled { for _, b := range f.Blocks { seenNonPhi := false for _, v := range b.Values { switch v.Op { case OpPhi: if seenNonPhi { f.Fatalf("phi after non-phi @ %s: %s", b, v) } default: seenNonPhi = true } } } } } // domCheck reports whether x dominates y (including x==y). func domCheck(f *Func, sdom SparseTree, x, y *Block) bool { if !sdom.IsAncestorEq(f.Entry, y) { // unreachable - ignore return true } return sdom.IsAncestorEq(x, y) } // isExactFloat32 reports whether x can be exactly represented as a float32. func isExactFloat32(x float64) bool { // Check the mantissa is in range. if bits.TrailingZeros64(math.Float64bits(x)) < 52-23 { return false } // Check the exponent is in range. The mantissa check above is sufficient for NaN values. return math.IsNaN(x) || x == float64(float32(x)) }