...
Run Format

Source file src/cmd/link/internal/ld/main.go

Documentation: cmd/link/internal/ld

  // Inferno utils/6l/obj.c
  // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/obj.c
  //
  //	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
  //	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
  //	Portions Copyright © 1997-1999 Vita Nuova Limited
  //	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
  //	Portions Copyright © 2004,2006 Bruce Ellis
  //	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
  //	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
  //	Portions Copyright © 2009 The Go Authors. All rights reserved.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  package ld
  
  import (
  	"bufio"
  	"cmd/internal/objabi"
  	"cmd/internal/sys"
  	"flag"
  	"log"
  	"os"
  	"runtime"
  	"runtime/pprof"
  	"strings"
  )
  
  var (
  	pkglistfornote []byte
  	windowsgui     bool // writes a "GUI binary" instead of a "console binary"
  )
  
  func init() {
  	flag.Var(&Linkmode, "linkmode", "set link `mode`")
  	flag.Var(&Buildmode, "buildmode", "set build `mode`")
  	flag.Var(&rpath, "r", "set the ELF dynamic linker search `path` to dir1:dir2:...")
  }
  
  // Flags used by the linker. The exported flags are used by the architecture-specific packages.
  var (
  	flagBuildid = flag.String("buildid", "", "record `id` as Go toolchain build id")
  
  	flagOutfile    = flag.String("o", "", "write output to `file`")
  	flagPluginPath = flag.String("pluginpath", "", "full path name for plugin")
  	FlagLinkshared = flag.Bool("linkshared", false, "link against installed Go shared libraries")
  
  	flagInstallSuffix = flag.String("installsuffix", "", "set package directory `suffix`")
  	flagDumpDep       = flag.Bool("dumpdep", false, "dump symbol dependency graph")
  	flagRace          = flag.Bool("race", false, "enable race detector")
  	flagMsan          = flag.Bool("msan", false, "enable MSan interface")
  
  	flagFieldTrack = flag.String("k", "", "set field tracking `symbol`")
  	flagLibGCC     = flag.String("libgcc", "", "compiler support lib for internal linking; use \"none\" to disable")
  	flagTmpdir     = flag.String("tmpdir", "", "use `directory` for temporary files")
  
  	flagExtld      = flag.String("extld", "", "use `linker` when linking in external mode")
  	flagExtldflags = flag.String("extldflags", "", "pass `flags` to external linker")
  	flagExtar      = flag.String("extar", "", "archive program for buildmode=c-archive")
  
  	flagA           = flag.Bool("a", false, "disassemble output")
  	FlagC           = flag.Bool("c", false, "dump call graph")
  	FlagD           = flag.Bool("d", false, "disable dynamic executable")
  	flagF           = flag.Bool("f", false, "ignore version mismatch")
  	flagG           = flag.Bool("g", false, "disable go package data checks")
  	flagH           = flag.Bool("h", false, "halt on error")
  	flagN           = flag.Bool("n", false, "dump symbol table")
  	FlagS           = flag.Bool("s", false, "disable symbol table")
  	flagU           = flag.Bool("u", false, "reject unsafe packages")
  	FlagW           = flag.Bool("w", false, "disable DWARF generation")
  	Flag8           bool // use 64-bit addresses in symbol table
  	flagInterpreter = flag.String("I", "", "use `linker` as ELF dynamic linker")
  	FlagDebugTramp  = flag.Int("debugtramp", 0, "debug trampolines")
  
  	flagHeadtype    = flag.String("H", "", "set header `type`")
  	FlagRound       = flag.Int("R", -1, "set address rounding `quantum`")
  	FlagTextAddr    = flag.Int64("T", -1, "set text segment `address`")
  	FlagDataAddr    = flag.Int64("D", -1, "set data segment `address`")
  	flagEntrySymbol = flag.String("E", "", "set `entry` symbol name")
  
  	cpuprofile     = flag.String("cpuprofile", "", "write cpu profile to `file`")
  	memprofile     = flag.String("memprofile", "", "write memory profile to `file`")
  	memprofilerate = flag.Int64("memprofilerate", 0, "set runtime.MemProfileRate to `rate`")
  )
  
  // Main is the main entry point for the linker code.
  func Main() {
  	ctxt := linknew(SysArch)
  	ctxt.Bso = bufio.NewWriter(os.Stdout)
  
  	// For testing behavior of go command when tools crash silently.
  	// Undocumented, not in standard flag parser to avoid
  	// exposing in usage message.
  	for _, arg := range os.Args {
  		if arg == "-crash_for_testing" {
  			os.Exit(2)
  		}
  	}
  
  	// TODO(matloob): define these above and then check flag values here
  	if SysArch.Family == sys.AMD64 && objabi.GOOS == "plan9" {
  		flag.BoolVar(&Flag8, "8", false, "use 64-bit addresses in symbol table")
  	}
  	objabi.Flagfn1("B", "add an ELF NT_GNU_BUILD_ID `note` when using ELF", addbuildinfo)
  	objabi.Flagfn1("L", "add specified `directory` to library path", func(a string) { Lflag(ctxt, a) })
  	objabi.Flagfn0("V", "print version and exit", doversion)
  	objabi.Flagfn1("X", "add string value `definition` of the form importpath.name=value", func(s string) { addstrdata1(ctxt, s) })
  	objabi.Flagcount("v", "print link trace", &ctxt.Debugvlog)
  	objabi.Flagfn1("importcfg", "read import configuration from `file`", ctxt.readImportCfg)
  
  	objabi.Flagparse(usage)
  
  	switch *flagHeadtype {
  	case "":
  	case "windowsgui":
  		Headtype = objabi.Hwindows
  		windowsgui = true
  	default:
  		if err := Headtype.Set(*flagHeadtype); err != nil {
  			Errorf(nil, "%v", err)
  			usage()
  		}
  	}
  
  	startProfile()
  	if Buildmode == BuildmodeUnset {
  		Buildmode = BuildmodeExe
  	}
  
  	if Buildmode != BuildmodeShared && flag.NArg() != 1 {
  		usage()
  	}
  
  	if *flagOutfile == "" {
  		*flagOutfile = "a.out"
  		if Headtype == objabi.Hwindows {
  			*flagOutfile += ".exe"
  		}
  	}
  
  	interpreter = *flagInterpreter
  
  	libinit(ctxt) // creates outfile
  
  	if Headtype == objabi.Hunknown {
  		Headtype.Set(objabi.GOOS)
  	}
  
  	ctxt.computeTLSOffset()
  	Thearch.Archinit(ctxt)
  
  	if *FlagLinkshared && !Iself {
  		Exitf("-linkshared can only be used on elf systems")
  	}
  
  	if ctxt.Debugvlog != 0 {
  		ctxt.Logf("HEADER = -H%d -T0x%x -D0x%x -R0x%x\n", Headtype, uint64(*FlagTextAddr), uint64(*FlagDataAddr), uint32(*FlagRound))
  	}
  
  	switch Buildmode {
  	case BuildmodeShared:
  		for i := 0; i < flag.NArg(); i++ {
  			arg := flag.Arg(i)
  			parts := strings.SplitN(arg, "=", 2)
  			var pkgpath, file string
  			if len(parts) == 1 {
  				pkgpath, file = "main", arg
  			} else {
  				pkgpath, file = parts[0], parts[1]
  			}
  			pkglistfornote = append(pkglistfornote, pkgpath...)
  			pkglistfornote = append(pkglistfornote, '\n')
  			addlibpath(ctxt, "command line", "command line", file, pkgpath, "")
  		}
  	case BuildmodePlugin:
  		addlibpath(ctxt, "command line", "command line", flag.Arg(0), *flagPluginPath, "")
  	default:
  		addlibpath(ctxt, "command line", "command line", flag.Arg(0), "main", "")
  	}
  	ctxt.loadlib()
  
  	ctxt.checkstrdata()
  	deadcode(ctxt)
  	fieldtrack(ctxt)
  	ctxt.callgraph()
  
  	ctxt.doelf()
  	if Headtype == objabi.Hdarwin {
  		ctxt.domacho()
  	}
  	ctxt.dostkcheck()
  	if Headtype == objabi.Hwindows {
  		ctxt.dope()
  	}
  	ctxt.addexport()
  	Thearch.Gentext(ctxt) // trampolines, call stubs, etc.
  	ctxt.textbuildid()
  	ctxt.textaddress()
  	ctxt.pclntab()
  	ctxt.findfunctab()
  	ctxt.typelink()
  	ctxt.symtab()
  	ctxt.dodata()
  	ctxt.address()
  	ctxt.reloc()
  	Thearch.Asmb(ctxt)
  	ctxt.undef()
  	ctxt.hostlink()
  	ctxt.archive()
  	if ctxt.Debugvlog != 0 {
  		ctxt.Logf("%5.2f cpu time\n", Cputime())
  		ctxt.Logf("%d symbols\n", len(ctxt.Syms.Allsym))
  		ctxt.Logf("%d liveness data\n", liveness)
  	}
  
  	ctxt.Bso.Flush()
  
  	errorexit()
  }
  
  type Rpath struct {
  	set bool
  	val string
  }
  
  func (r *Rpath) Set(val string) error {
  	r.set = true
  	r.val = val
  	return nil
  }
  
  func (r *Rpath) String() string {
  	return r.val
  }
  
  func startProfile() {
  	if *cpuprofile != "" {
  		f, err := os.Create(*cpuprofile)
  		if err != nil {
  			log.Fatalf("%v", err)
  		}
  		if err := pprof.StartCPUProfile(f); err != nil {
  			log.Fatalf("%v", err)
  		}
  		AtExit(pprof.StopCPUProfile)
  	}
  	if *memprofile != "" {
  		if *memprofilerate != 0 {
  			runtime.MemProfileRate = int(*memprofilerate)
  		}
  		f, err := os.Create(*memprofile)
  		if err != nil {
  			log.Fatalf("%v", err)
  		}
  		AtExit(func() {
  			runtime.GC() // profile all outstanding allocations
  			if err := pprof.WriteHeapProfile(f); err != nil {
  				log.Fatalf("%v", err)
  			}
  		})
  	}
  }
  

View as plain text