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// Inferno utils/6l/obj.c
// https://bitbucket.org/inferno-os/inferno-os/src/master/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/goobj"
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/benchmark"
"flag"
"internal/buildcfg"
"log"
"os"
"runtime"
"runtime/pprof"
"strings"
)
var (
pkglistfornote []byte
windowsgui bool // writes a "GUI binary" instead of a "console binary"
ownTmpDir bool // set to true if tmp dir created by linker (e.g. no -tmpdir)
)
func init() {
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")
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")
flagAslr = flag.Bool("aslr", true, "enable ASLR for buildmode=c-shared on windows")
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, "no-op (deprecated)")
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")
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")
FlagDebugTextSize = flag.Int("debugtextsize", 0, "debug text section max size")
FlagStrictDups = flag.Int("strictdups", 0, "sanity check duplicate symbol contents during object file reading (1=warn 2=err).")
FlagRound = flag.Int("R", -1, "set address rounding `quantum`")
FlagTextAddr = flag.Int64("T", -1, "set text 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`")
benchmarkFlag = flag.String("benchmark", "", "set to 'mem' or 'cpu' to enable phase benchmarking")
benchmarkFileFlag = flag.String("benchmarkprofile", "", "emit phase profiles to `base`_phase.{cpu,mem}prof")
)
// Main is the main entry point for the linker code.
func Main(arch *sys.Arch, theArch Arch) {
thearch = theArch
ctxt := linknew(arch)
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)
}
}
final := gorootFinal()
addstrdata1(ctxt, "runtime.defaultGOROOT="+final)
addstrdata1(ctxt, "internal/buildcfg.defaultGOROOT="+final)
buildVersion := buildcfg.Version
if goexperiment := buildcfg.GOEXPERIMENT(); goexperiment != "" {
buildVersion += " X:" + goexperiment
}
addstrdata1(ctxt, "runtime.buildVersion="+buildVersion)
// TODO(matloob): define these above and then check flag values here
if ctxt.Arch.Family == sys.AMD64 && buildcfg.GOOS == "plan9" {
flag.BoolVar(&flag8, "8", false, "use 64-bit addresses in symbol table")
}
flagHeadType := flag.String("H", "", "set header `type`")
flag.BoolVar(&ctxt.linkShared, "linkshared", false, "link against installed Go shared libraries")
flag.Var(&ctxt.LinkMode, "linkmode", "set link `mode`")
flag.Var(&ctxt.BuildMode, "buildmode", "set build `mode`")
flag.BoolVar(&ctxt.compressDWARF, "compressdwarf", true, "compress DWARF if possible")
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.AddVersionFlag() // -V
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)
if ctxt.Debugvlog > 0 {
// dump symbol info on crash
defer func() { ctxt.loader.Dump() }()
}
switch *flagHeadType {
case "":
case "windowsgui":
ctxt.HeadType = objabi.Hwindows
windowsgui = true
default:
if err := ctxt.HeadType.Set(*flagHeadType); err != nil {
Errorf(nil, "%v", err)
usage()
}
}
if ctxt.HeadType == objabi.Hunknown {
ctxt.HeadType.Set(buildcfg.GOOS)
}
if !*flagAslr && ctxt.BuildMode != BuildModeCShared {
Errorf(nil, "-aslr=false is only allowed for -buildmode=c-shared")
usage()
}
checkStrictDups = *FlagStrictDups
startProfile()
if ctxt.BuildMode == BuildModeUnset {
ctxt.BuildMode.Set("exe")
}
if ctxt.BuildMode != BuildModeShared && flag.NArg() != 1 {
usage()
}
if *flagOutfile == "" {
*flagOutfile = "a.out"
if ctxt.HeadType == objabi.Hwindows {
*flagOutfile += ".exe"
}
}
interpreter = *flagInterpreter
if *flagBuildid == "" && ctxt.Target.IsOpenbsd() {
// TODO(jsing): Remove once direct syscalls are no longer in use.
// OpenBSD 6.7 onwards will not permit direct syscalls from a
// dynamically linked binary unless it identifies the binary
// contains a .note.go.buildid ELF note. See issue #36435.
*flagBuildid = "go-openbsd"
}
// enable benchmarking
var bench *benchmark.Metrics
if len(*benchmarkFlag) != 0 {
if *benchmarkFlag == "mem" {
bench = benchmark.New(benchmark.GC, *benchmarkFileFlag)
} else if *benchmarkFlag == "cpu" {
bench = benchmark.New(benchmark.NoGC, *benchmarkFileFlag)
} else {
Errorf(nil, "unknown benchmark flag: %q", *benchmarkFlag)
usage()
}
}
bench.Start("libinit")
libinit(ctxt) // creates outfile
bench.Start("computeTLSOffset")
ctxt.computeTLSOffset()
bench.Start("Archinit")
thearch.Archinit(ctxt)
if ctxt.linkShared && !ctxt.IsELF {
Exitf("-linkshared can only be used on elf systems")
}
if ctxt.Debugvlog != 0 {
ctxt.Logf("HEADER = -H%d -T0x%x -R0x%x\n", ctxt.HeadType, uint64(*FlagTextAddr), uint32(*FlagRound))
}
zerofp := goobj.FingerprintType{}
switch ctxt.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, "", zerofp)
}
case BuildModePlugin:
addlibpath(ctxt, "command line", "command line", flag.Arg(0), *flagPluginPath, "", zerofp)
default:
addlibpath(ctxt, "command line", "command line", flag.Arg(0), "main", "", zerofp)
}
bench.Start("loadlib")
ctxt.loadlib()
bench.Start("deadcode")
deadcode(ctxt)
bench.Start("linksetup")
ctxt.linksetup()
bench.Start("dostrdata")
ctxt.dostrdata()
if buildcfg.Experiment.FieldTrack {
bench.Start("fieldtrack")
fieldtrack(ctxt.Arch, ctxt.loader)
}
bench.Start("dwarfGenerateDebugInfo")
dwarfGenerateDebugInfo(ctxt)
bench.Start("callgraph")
ctxt.callgraph()
bench.Start("dostkcheck")
ctxt.dostkcheck()
bench.Start("mangleTypeSym")
ctxt.mangleTypeSym()
if ctxt.IsELF {
bench.Start("doelf")
ctxt.doelf()
}
if ctxt.IsDarwin() {
bench.Start("domacho")
ctxt.domacho()
}
if ctxt.IsWindows() {
bench.Start("dope")
ctxt.dope()
bench.Start("windynrelocsyms")
ctxt.windynrelocsyms()
}
if ctxt.IsAIX() {
bench.Start("doxcoff")
ctxt.doxcoff()
}
bench.Start("textbuildid")
ctxt.textbuildid()
bench.Start("addexport")
ctxt.setArchSyms()
ctxt.addexport()
bench.Start("Gentext")
thearch.Gentext(ctxt, ctxt.loader) // trampolines, call stubs, etc.
bench.Start("textaddress")
ctxt.textaddress()
bench.Start("typelink")
ctxt.typelink()
bench.Start("buildinfo")
ctxt.buildinfo()
bench.Start("pclntab")
containers := ctxt.findContainerSyms()
pclnState := ctxt.pclntab(containers)
bench.Start("findfunctab")
ctxt.findfunctab(pclnState, containers)
bench.Start("dwarfGenerateDebugSyms")
dwarfGenerateDebugSyms(ctxt)
bench.Start("symtab")
symGroupType := ctxt.symtab(pclnState)
bench.Start("dodata")
ctxt.dodata(symGroupType)
bench.Start("address")
order := ctxt.address()
bench.Start("dwarfcompress")
dwarfcompress(ctxt)
bench.Start("layout")
filesize := ctxt.layout(order)
// Write out the output file.
// It is split into two parts (Asmb and Asmb2). The first
// part writes most of the content (sections and segments),
// for which we have computed the size and offset, in a
// mmap'd region. The second part writes more content, for
// which we don't know the size.
if ctxt.Arch.Family != sys.Wasm {
// Don't mmap if we're building for Wasm. Wasm file
// layout is very different so filesize is meaningless.
if err := ctxt.Out.Mmap(filesize); err != nil {
Exitf("mapping output file failed: %v", err)
}
}
// asmb will redirect symbols to the output file mmap, and relocations
// will be applied directly there.
bench.Start("Asmb")
asmb(ctxt)
exitIfErrors()
// Generate additional symbols for the native symbol table just prior
// to code generation.
bench.Start("GenSymsLate")
if thearch.GenSymsLate != nil {
thearch.GenSymsLate(ctxt, ctxt.loader)
}
bench.Start("Asmb2")
asmb2(ctxt)
bench.Start("Munmap")
ctxt.Out.Close() // Close handles Munmapping if necessary.
bench.Start("hostlink")
ctxt.hostlink()
if ctxt.Debugvlog != 0 {
ctxt.Logf("%s", ctxt.loader.Stat())
ctxt.Logf("%d liveness data\n", liveness)
}
bench.Start("Flush")
ctxt.Bso.Flush()
bench.Start("archive")
ctxt.archive()
bench.Report(os.Stdout)
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() {
// Profile all outstanding allocations.
runtime.GC()
// compilebench parses the memory profile to extract memstats,
// which are only written in the legacy pprof format.
// See golang.org/issue/18641 and runtime/pprof/pprof.go:writeHeap.
const writeLegacyFormat = 1
if err := pprof.Lookup("heap").WriteTo(f, writeLegacyFormat); err != nil {
log.Fatalf("%v", err)
}
})
}
}
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