"os/exec"
"path/filepath"
"runtime"
+ "sort"
"strings"
"sync"
DynStr loader.Sym
unreachableMethod loader.Sym
+
+ // Symbol containing a list of all the inittasks that need
+ // to be run at startup.
+ mainInittasks loader.Sym
}
// mkArchSym is a helper for setArchSyms, to set up a special symbol.
ctxt.loader.SetAttrReachable(*ls, true)
}
-// mkArchVecSym is similar to setArchSyms, but operates on elements within
+// mkArchSymVec is similar to setArchSyms, but operates on elements within
// a slice, where each element corresponds to some symbol version.
func (ctxt *Link) mkArchSymVec(name string, ver int, ls []loader.Sym) {
ls[ver] = ctxt.loader.LookupOrCreateSym(name, ver)
// We leave some room for extra stuff like PLT stubs.
TrampLimit uint64
- Androiddynld string
- Linuxdynld string
- LinuxdynldMusl string
- Freebsddynld string
- Netbsddynld string
- Openbsddynld string
- Dragonflydynld string
- Solarisdynld string
-
// Empty spaces between codeblocks will be padded with this value.
// For example an architecture might want to pad with a trap instruction to
// catch wayward programs. Architectures that do not define a padding value
// is the contents of the to-be-relocated data item (from sym.P). Return
// value is the appropriately relocated value (to be written back to the
// same spot in sym.P), number of external _host_ relocations needed (i.e.
- // ELF/Mach-O/etc. relocations, not Go relocations, this must match Elfreloc1,
+ // ELF/Mach-O/etc. relocations, not Go relocations, this must match ELF.Reloc1,
// etc.), and a boolean indicating success/failure (a failing value indicates
// a fatal error).
Archreloc func(*Target, *loader.Loader, *ArchSyms, loader.Reloc, loader.Sym,
// needed.
Extreloc func(*Target, *loader.Loader, loader.Reloc, loader.Sym) (loader.ExtReloc, bool)
- Elfreloc1 func(*Link, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int, int64) bool
- ElfrelocSize uint32 // size of an ELF relocation record, must match Elfreloc1.
- Elfsetupplt func(ctxt *Link, plt, gotplt *loader.SymbolBuilder, dynamic loader.Sym)
Gentext func(*Link, *loader.Loader) // Generate text before addressing has been performed.
Machoreloc1 func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool
MachorelocSize uint32 // size of an Mach-O relocation record, must match Machoreloc1.
// optional override for assignAddress
AssignAddress func(ldr *loader.Loader, sect *sym.Section, n int, s loader.Sym, va uint64, isTramp bool) (*sym.Section, int, uint64)
+
+ // ELF specific information.
+ ELF ELFArch
}
var (
Segrelrodata sym.Segment
Segdata sym.Segment
Segdwarf sym.Segment
+ Segpdata sym.Segment // windows-only
+ Segxdata sym.Segment // windows-only
- Segments = []*sym.Segment{&Segtext, &Segrodata, &Segrelrodata, &Segdata, &Segdwarf}
+ Segments = []*sym.Segment{&Segtext, &Segrodata, &Segrelrodata, &Segdata, &Segdwarf, &Segpdata, &Segxdata}
)
const pkgdef = "__.PKGDEF"
// any of these objects, we must link externally. Issue 52863.
dynimportfail []string
+ // preferlinkext is a list of packages for which the Go command
+ // noticed use of peculiar C flags. If we see any of these,
+ // default to linking externally unless overridden by the
+ // user. See issues #58619, #58620, and #58848.
+ preferlinkext []string
+
// unknownObjFormat is set to true if we see an object whose
// format we don't recognize.
unknownObjFormat = false
default:
log.Fatalf("invalid -strictdups flag value %d", *FlagStrictDups)
}
- elfsetstring1 := func(str string, off int) { elfsetstring(ctxt, 0, str, off) }
- ctxt.loader = loader.NewLoader(flags, elfsetstring1, &ctxt.ErrorReporter.ErrorReporter)
+ ctxt.loader = loader.NewLoader(flags, &ctxt.ErrorReporter.ErrorReporter)
ctxt.ErrorReporter.SymName = func(s loader.Sym) string {
return ctxt.loader.SymName(s)
}
if *flagLibGCC != "none" {
hostArchive(ctxt, *flagLibGCC)
}
+ // For glibc systems, the linker setup used by GCC
+ // looks like
+ //
+ // GROUP ( /lib/x86_64-linux-gnu/libc.so.6
+ // /usr/lib/x86_64-linux-gnu/libc_nonshared.a
+ // AS_NEEDED ( /lib64/ld-linux-x86-64.so.2 ) )
+ //
+ // where libc_nonshared.a contains a small set of
+ // symbols including "__stack_chk_fail_local" and a
+ // few others. Thus if we are doing internal linking
+ // and "__stack_chk_fail_local" is unresolved (most
+ // likely due to the use of -fstack-protector), try
+ // loading libc_nonshared.a to resolve it.
+ //
+ // On Alpine Linux (musl-based), the library providing
+ // this symbol is called libssp_nonshared.a.
+ isunresolved := symbolsAreUnresolved(ctxt, []string{"__stack_chk_fail_local"})
+ if isunresolved[0] {
+ if p := ctxt.findLibPath("libc_nonshared.a"); p != "none" {
+ hostArchive(ctxt, p)
+ }
+ if p := ctxt.findLibPath("libssp_nonshared.a"); p != "none" {
+ hostArchive(ctxt, p)
+ }
+ }
}
}
// We've loaded all the code now.
ctxt.Loaded = true
- importcycles()
-
strictDupMsgCount = ctxt.loader.NStrictDupMsgs()
}
ctxt.loader.SetAttrSpecial(sb.Sym(), true)
}
}
+
+ // Fix up references to DLL import symbols now that we're done
+ // pulling in new objects.
+ if err := loadpe.PostProcessImports(); err != nil {
+ Errorf(nil, "%v", err)
+ }
+
// TODO: maybe do something similar to peimporteddlls to collect
// all lib names and try link them all to final exe just like
// libmingwex.a and libmingw32.a:
// Leave type:runtime. symbols alone, because other parts of
// the linker manipulates them.
func typeSymbolMangle(name string) string {
- if !strings.HasPrefix(name, "type:") {
+ isType := strings.HasPrefix(name, "type:")
+ if !isType && !strings.Contains(name, "@") {
+ // Issue 58800: instantiated symbols may include a type name, which may contain "@"
return name
}
if strings.HasPrefix(name, "type:runtime.") {
return name
}
+ if strings.HasPrefix(name, "go:string.") {
+ // String symbols will be grouped to a single go:string.* symbol.
+ // No need to mangle individual symbol names.
+ return name
+ }
if len(name) <= 14 && !strings.Contains(name, "@") { // Issue 19529
return name
}
- hash := notsha256.Sum256([]byte(name))
- prefix := "type:"
- if name[5] == '.' {
- prefix = "type:."
+ if isType {
+ hash := notsha256.Sum256([]byte(name[5:]))
+ prefix := "type:"
+ if name[5] == '.' {
+ prefix = "type:."
+ }
+ return prefix + base64.StdEncoding.EncodeToString(hash[:6])
+ }
+ // instantiated symbol, replace type name in []
+ i := strings.IndexByte(name, '[')
+ j := strings.LastIndexByte(name, ']')
+ if j == -1 || j <= i {
+ j = len(name)
}
- return prefix + base64.StdEncoding.EncodeToString(hash[:6])
+ hash := notsha256.Sum256([]byte(name[i+1 : j]))
+ return name[:i+1] + base64.StdEncoding.EncodeToString(hash[:6]) + name[j:]
}
/*
if arhdr.name == "dynimportfail" {
dynimportfail = append(dynimportfail, lib.Pkg)
}
+ if arhdr.name == "preferlinkext" {
+ // Ignore this directive if -linkmode has been
+ // set explicitly.
+ if ctxt.LinkMode == LinkAuto {
+ preferlinkext = append(preferlinkext, lib.Pkg)
+ }
+ }
// Skip other special (non-object-file) sections that
// build tools may have added. Such sections must have
// hostobjCopy creates a copy of the object files in hostobj in a
// temporary directory.
-func hostobjCopy() (paths []string) {
+func (ctxt *Link) hostobjCopy() (paths []string) {
var wg sync.WaitGroup
sema := make(chan struct{}, runtime.NumCPU()) // limit open file descriptors
for i, h := range hostobj {
h := h
dst := filepath.Join(*flagTmpdir, fmt.Sprintf("%06d.o", i))
paths = append(paths, dst)
+ if ctxt.Debugvlog != 0 {
+ ctxt.Logf("host obj copy: %s from pkg %s -> %s\n", h.pn, h.pkg, dst)
+ }
wg.Add(1)
go func() {
}
argv = append(argv, *flagOutfile)
argv = append(argv, filepath.Join(*flagTmpdir, "go.o"))
- argv = append(argv, hostobjCopy()...)
+ argv = append(argv, ctxt.hostobjCopy()...)
if ctxt.Debugvlog != 0 {
ctxt.Logf("archive: %s\n", strings.Join(argv, " "))
if ctxt.HeadType == objabi.Hdarwin {
// Recent versions of macOS print
// ld: warning: option -s is obsolete and being ignored
- // so do not pass any arguments.
+ // so do not pass any arguments (but we strip symbols below).
} else {
argv = append(argv, "-s")
}
// On darwin, whether to combine DWARF into executable.
// Only macOS supports unmapped segments such as our __DWARF segment.
- combineDwarf := ctxt.IsDarwin() && !*FlagS && !*FlagW && !debug_s && machoPlatform == PLATFORM_MACOS
+ combineDwarf := ctxt.IsDarwin() && !*FlagW && machoPlatform == PLATFORM_MACOS
switch ctxt.HeadType {
case objabi.Hdarwin:
}
if !combineDwarf {
argv = append(argv, "-Wl,-S") // suppress STAB (symbolic debugging) symbols
+ if debug_s {
+ // We are generating a binary with symbol table suppressed.
+ // Suppress local symbols. We need to keep dynamically exported
+ // and referenced symbols so the dynamic linker can resolve them.
+ argv = append(argv, "-Wl,-x")
+ }
}
case objabi.Hopenbsd:
argv = append(argv, "-Wl,-nopie")
argv = append(argv, "-pthread")
+ if ctxt.Arch.InFamily(sys.ARM64) {
+ // Disable execute-only on openbsd/arm64 - the Go arm64 assembler
+ // currently stores constants in the text section rather than in rodata.
+ // See issue #59615.
+ argv = append(argv, "-Wl,--no-execute-only")
+ }
case objabi.Hwindows:
if windowsgui {
argv = append(argv, "-mwindows")
argv = append(argv, "-Wl,-bbigtoc")
}
+ // On PPC64, verify the external toolchain supports Power10. This is needed when
+ // PC relative relocations might be generated by Go. Only targets compiling ELF
+ // binaries might generate these relocations.
+ if ctxt.IsPPC64() && ctxt.IsElf() && buildcfg.GOPPC64 >= 10 {
+ if !linkerFlagSupported(ctxt.Arch, argv[0], "", "-mcpu=power10") {
+ Exitf("The external toolchain does not support -mcpu=power10. " +
+ " This is required to externally link GOPPC64 >= power10")
+ }
+ }
+
// Enable/disable ASLR on Windows.
addASLRargs := func(argv []string, val bool) []string {
// Old/ancient versions of GCC support "--dynamicbase" and
altLinker = "lld"
}
- if ctxt.Arch.InFamily(sys.ARM, sys.ARM64) && buildcfg.GOOS == "linux" {
- // On ARM, the GNU linker will generate COPY relocations
- // even with -znocopyreloc set.
+ if ctxt.Arch.InFamily(sys.ARM64) && buildcfg.GOOS == "linux" {
+ // On ARM64, the GNU linker will fail with
+ // -znocopyreloc if it thinks a COPY relocation is
+ // required. Switch to gold.
// https://sourceware.org/bugzilla/show_bug.cgi?id=19962
- //
- // On ARM64, the GNU linker will fail instead of
- // generating COPY relocations.
- //
- // In both cases, switch to gold.
+ // https://go.dev/issue/22040
altLinker = "gold"
// If gold is not installed, gcc will silently switch
cmd := exec.Command(name, args...)
if out, err := cmd.CombinedOutput(); err == nil {
if !bytes.Contains(out, []byte("GNU gold")) {
- log.Fatalf("ARM external linker must be gold (issue #15696), but is not: %s", out)
+ log.Fatalf("ARM64 external linker must be gold (issue #15696, 22040), but is not: %s", out)
}
}
}
// Force global symbols to be exported for dlopen, etc.
if ctxt.IsELF {
- argv = append(argv, "-rdynamic")
+ if ctxt.DynlinkingGo() || ctxt.BuildMode == BuildModeCShared || !linkerFlagSupported(ctxt.Arch, argv[0], altLinker, "-Wl,--export-dynamic-symbol=main") {
+ argv = append(argv, "-rdynamic")
+ } else {
+ var exports []string
+ ctxt.loader.ForAllCgoExportDynamic(func(s loader.Sym) {
+ exports = append(exports, "-Wl,--export-dynamic-symbol="+ctxt.loader.SymExtname(s))
+ })
+ sort.Strings(exports)
+ argv = append(argv, exports...)
+ }
}
if ctxt.HeadType == objabi.Haix {
fileName := xcoffCreateExportFile(ctxt)
argv = append(argv, unusedArguments)
}
+ if ctxt.IsWindows() {
+ // Suppress generation of the PE file header timestamp,
+ // so as to avoid spurious build ID differences between
+ // linked binaries that are otherwise identical other than
+ // the date/time they were linked.
+ const noTimeStamp = "-Wl,--no-insert-timestamp"
+ if linkerFlagSupported(ctxt.Arch, argv[0], altLinker, noTimeStamp) {
+ argv = append(argv, noTimeStamp)
+ }
+ }
+
const compressDWARF = "-Wl,--compress-debug-sections=zlib"
if ctxt.compressDWARF && linkerFlagSupported(ctxt.Arch, argv[0], altLinker, compressDWARF) {
argv = append(argv, compressDWARF)
}
argv = append(argv, filepath.Join(*flagTmpdir, "go.o"))
- argv = append(argv, hostobjCopy()...)
+ argv = append(argv, ctxt.hostobjCopy()...)
if ctxt.HeadType == objabi.Haix {
// We want to have C files after Go files to remove
// trampolines csects made by ld.
// case used has specified "-fuse-ld=...".
extld := ctxt.extld()
name, args := extld[0], extld[1:]
- args = append(args, flagExtldflags...)
+ args = append(args, trimLinkerArgv(flagExtldflags)...)
args = append(args, "-Wl,--version")
cmd := exec.Command(name, args...)
usingLLD := false
argv = append(argv, peimporteddlls()...)
}
+ argv = ctxt.passLongArgsInResponseFile(argv, altLinker)
+
if ctxt.Debugvlog != 0 {
ctxt.Logf("host link:")
for _, v := range argv {
out = append(out[:i], out[i+len(noPieWarning):]...)
}
}
+ if ctxt.IsDarwin() {
+ const bindAtLoadWarning = "ld: warning: -bind_at_load is deprecated on macOS\n"
+ if i := bytes.Index(out, []byte(bindAtLoadWarning)); i >= 0 {
+ // -bind_at_load is deprecated with ld-prime, but needed for
+ // correctness with older versions of ld64. Swallow the warning.
+ // TODO: maybe pass -bind_at_load conditionally based on C
+ // linker version.
+ out = append(out[:i], out[i+len(bindAtLoadWarning):]...)
+ }
+ }
ctxt.Logf("%s", out)
}
stripCmd := strings.TrimSuffix(string(out), "\n")
dsym := filepath.Join(*flagTmpdir, "go.dwarf")
- if out, err := exec.Command(dsymutilCmd, "-f", *flagOutfile, "-o", dsym).CombinedOutput(); err != nil {
+ cmd := exec.Command(dsymutilCmd, "-f", *flagOutfile, "-o", dsym)
+ // dsymutil may not clean up its temp directory at exit.
+ // Set DSYMUTIL_REPRODUCER_PATH to work around. see issue 59026.
+ cmd.Env = append(os.Environ(), "DSYMUTIL_REPRODUCER_PATH="+*flagTmpdir)
+ if ctxt.Debugvlog != 0 {
+ ctxt.Logf("host link dsymutil:")
+ for _, v := range cmd.Args {
+ ctxt.Logf(" %q", v)
+ }
+ ctxt.Logf("\n")
+ }
+ if out, err := cmd.CombinedOutput(); err != nil {
Exitf("%s: running dsymutil failed: %v\n%s", os.Args[0], err, out)
}
// Remove STAB (symbolic debugging) symbols after we are done with them (by dsymutil).
// They contain temporary file paths and make the build not reproducible.
- if out, err := exec.Command(stripCmd, "-S", *flagOutfile).CombinedOutput(); err != nil {
+ var stripArgs = []string{"-S"}
+ if debug_s {
+ // We are generating a binary with symbol table suppressed.
+ // Suppress local symbols. We need to keep dynamically exported
+ // and referenced symbols so the dynamic linker can resolve them.
+ stripArgs = append(stripArgs, "-x")
+ }
+ stripArgs = append(stripArgs, *flagOutfile)
+ if ctxt.Debugvlog != 0 {
+ ctxt.Logf("host link strip: %q", stripCmd)
+ for _, v := range stripArgs {
+ ctxt.Logf(" %q", v)
+ }
+ ctxt.Logf("\n")
+ }
+ if out, err := exec.Command(stripCmd, stripArgs...).CombinedOutput(); err != nil {
Exitf("%s: running strip failed: %v\n%s", os.Args[0], err, out)
}
// Skip combining if `dsymutil` didn't generate a file. See #11994.
}
}
+// passLongArgsInResponseFile writes the arguments into a file if they
+// are very long.
+func (ctxt *Link) passLongArgsInResponseFile(argv []string, altLinker string) []string {
+ c := 0
+ for _, arg := range argv {
+ c += len(arg)
+ }
+
+ if c < sys.ExecArgLengthLimit {
+ return argv
+ }
+
+ // Only use response files if they are supported.
+ response := filepath.Join(*flagTmpdir, "response")
+ if err := os.WriteFile(response, nil, 0644); err != nil {
+ log.Fatalf("failed while testing response file: %v", err)
+ }
+ if !linkerFlagSupported(ctxt.Arch, argv[0], altLinker, "@"+response) {
+ if ctxt.Debugvlog != 0 {
+ ctxt.Logf("not using response file because linker does not support one")
+ }
+ return argv
+ }
+
+ var buf bytes.Buffer
+ for _, arg := range argv[1:] {
+ // The external linker response file supports quoted strings.
+ fmt.Fprintf(&buf, "%q\n", arg)
+ }
+ if err := os.WriteFile(response, buf.Bytes(), 0644); err != nil {
+ log.Fatalf("failed while writing response file: %v", err)
+ }
+ if ctxt.Debugvlog != 0 {
+ ctxt.Logf("response file %s contents:\n%s", response, buf.Bytes())
+ }
+ return []string{
+ argv[0],
+ "@" + response,
+ }
+}
+
var createTrivialCOnce sync.Once
func linkerFlagSupported(arch *sys.Arch, linker, altLinker, flag string) bool {
}
})
+ flags := hostlinkArchArgs(arch)
+
+ moreFlags := trimLinkerArgv(append(flagExtldflags, ldflag...))
+ flags = append(flags, moreFlags...)
+
+ if altLinker != "" {
+ flags = append(flags, "-fuse-ld="+altLinker)
+ }
+ trivialPath := filepath.Join(*flagTmpdir, "trivial.c")
+ outPath := filepath.Join(*flagTmpdir, "a.out")
+ flags = append(flags, "-o", outPath, flag, trivialPath)
+
+ cmd := exec.Command(linker, flags...)
+ cmd.Env = append([]string{"LC_ALL=C"}, os.Environ()...)
+ out, err := cmd.CombinedOutput()
+ // GCC says "unrecognized command line option ‘-no-pie’"
+ // clang says "unknown argument: '-no-pie'"
+ return err == nil && !bytes.Contains(out, []byte("unrecognized")) && !bytes.Contains(out, []byte("unknown"))
+}
+
+// trimLinkerArgv returns a new copy of argv that does not include flags
+// that are not relevant for testing whether some linker option works.
+func trimLinkerArgv(argv []string) []string {
flagsWithNextArgSkip := []string{
"-F",
"-l",
"-target",
}
- flags := hostlinkArchArgs(arch)
+ var flags []string
keep := false
skip := false
- for _, f := range append(flagExtldflags, ldflag...) {
+ for _, f := range argv {
if keep {
flags = append(flags, f)
keep = false
}
}
}
-
- if altLinker != "" {
- flags = append(flags, "-fuse-ld="+altLinker)
- }
- flags = append(flags, flag, "trivial.c")
-
- cmd := exec.Command(linker, flags...)
- cmd.Dir = *flagTmpdir
- cmd.Env = append([]string{"LC_ALL=C"}, os.Environ()...)
- out, err := cmd.CombinedOutput()
- // GCC says "unrecognized command line option ‘-no-pie’"
- // clang says "unknown argument: '-no-pie'"
- return err == nil && !bytes.Contains(out, []byte("unrecognized")) && !bytes.Contains(out, []byte("unknown"))
+ return flags
}
// hostlinkArchArgs returns arguments to pass to the external linker
0xc401, // arm
0x64aa: // arm64
ldpe := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
- textp, rsrc, err := loadpe.Load(ctxt.loader, ctxt.Arch, ctxt.IncVersion(), f, pkg, length, pn)
+ ls, err := loadpe.Load(ctxt.loader, ctxt.Arch, ctxt.IncVersion(), f, pkg, length, pn)
if err != nil {
Errorf(nil, "%v", err)
return
}
- if len(rsrc) != 0 {
- setpersrc(ctxt, rsrc)
+ if len(ls.Resources) != 0 {
+ setpersrc(ctxt, ls.Resources)
}
- ctxt.Textp = append(ctxt.Textp, textp...)
+ if ls.PData != 0 {
+ sehp.pdata = append(sehp.pdata, ls.PData)
+ }
+ if ls.XData != 0 {
+ sehp.xdata = append(sehp.xdata, ls.XData)
+ }
+ ctxt.Textp = append(ctxt.Textp, ls.Textp...)
}
return ldhostobj(ldpe, ctxt.HeadType, f, pkg, length, pn, file)
}