| // Inferno utils/8l/asm.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/master/utils/8l/asm.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 ( |
| "bytes" |
| "cmd/internal/bio" |
| "cmd/internal/goobj" |
| "cmd/internal/obj" |
| "cmd/internal/objabi" |
| "cmd/internal/sys" |
| "cmd/link/internal/loadelf" |
| "cmd/link/internal/loader" |
| "cmd/link/internal/loadmacho" |
| "cmd/link/internal/loadpe" |
| "cmd/link/internal/loadxcoff" |
| "cmd/link/internal/sym" |
| "crypto/sha1" |
| "debug/elf" |
| "debug/macho" |
| "encoding/base64" |
| "encoding/binary" |
| "fmt" |
| "internal/buildcfg" |
| exec "internal/execabs" |
| "io" |
| "io/ioutil" |
| "log" |
| "os" |
| "path/filepath" |
| "runtime" |
| "strings" |
| "sync" |
| ) |
| |
| // Data layout and relocation. |
| |
| // Derived from Inferno utils/6l/l.h |
| // https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h |
| // |
| // 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. |
| |
| // ArchSyms holds a number of architecture specific symbols used during |
| // relocation. Rather than allowing them universal access to all symbols, |
| // we keep a subset for relocation application. |
| type ArchSyms struct { |
| Rel loader.Sym |
| Rela loader.Sym |
| RelPLT loader.Sym |
| RelaPLT loader.Sym |
| |
| LinkEditGOT loader.Sym |
| LinkEditPLT loader.Sym |
| |
| TOC loader.Sym |
| DotTOC []loader.Sym // for each version |
| |
| GOT loader.Sym |
| PLT loader.Sym |
| GOTPLT loader.Sym |
| |
| Tlsg loader.Sym |
| Tlsoffset int |
| |
| Dynamic loader.Sym |
| DynSym loader.Sym |
| DynStr loader.Sym |
| |
| unreachableMethod loader.Sym |
| } |
| |
| // mkArchSym is a helper for setArchSyms, to set up a special symbol. |
| func (ctxt *Link) mkArchSym(name string, ver int, ls *loader.Sym) { |
| *ls = ctxt.loader.LookupOrCreateSym(name, ver) |
| ctxt.loader.SetAttrReachable(*ls, true) |
| } |
| |
| // mkArchVecSym 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) |
| ctxt.loader.SetAttrReachable(ls[ver], true) |
| } |
| |
| // setArchSyms sets up the ArchSyms structure, and must be called before |
| // relocations are applied. |
| func (ctxt *Link) setArchSyms() { |
| ctxt.mkArchSym(".got", 0, &ctxt.GOT) |
| ctxt.mkArchSym(".plt", 0, &ctxt.PLT) |
| ctxt.mkArchSym(".got.plt", 0, &ctxt.GOTPLT) |
| ctxt.mkArchSym(".dynamic", 0, &ctxt.Dynamic) |
| ctxt.mkArchSym(".dynsym", 0, &ctxt.DynSym) |
| ctxt.mkArchSym(".dynstr", 0, &ctxt.DynStr) |
| ctxt.mkArchSym("runtime.unreachableMethod", abiInternalVer, &ctxt.unreachableMethod) |
| |
| if ctxt.IsPPC64() { |
| ctxt.mkArchSym("TOC", 0, &ctxt.TOC) |
| |
| ctxt.DotTOC = make([]loader.Sym, ctxt.MaxVersion()+1) |
| for i := 0; i <= ctxt.MaxVersion(); i++ { |
| if i >= sym.SymVerABICount && i < sym.SymVerStatic { // these versions are not used currently |
| continue |
| } |
| ctxt.mkArchSymVec(".TOC.", i, ctxt.DotTOC) |
| } |
| } |
| if ctxt.IsElf() { |
| ctxt.mkArchSym(".rel", 0, &ctxt.Rel) |
| ctxt.mkArchSym(".rela", 0, &ctxt.Rela) |
| ctxt.mkArchSym(".rel.plt", 0, &ctxt.RelPLT) |
| ctxt.mkArchSym(".rela.plt", 0, &ctxt.RelaPLT) |
| } |
| if ctxt.IsDarwin() { |
| ctxt.mkArchSym(".linkedit.got", 0, &ctxt.LinkEditGOT) |
| ctxt.mkArchSym(".linkedit.plt", 0, &ctxt.LinkEditPLT) |
| } |
| } |
| |
| type Arch struct { |
| Funcalign int |
| Maxalign int |
| Minalign int |
| Dwarfregsp int |
| Dwarfreglr int |
| |
| // Threshold of total text size, used for trampoline insertion. If the total |
| // text size is smaller than TrampLimit, we won't need to insert trampolines. |
| // It is pretty close to the offset range of a direct CALL machine instruction. |
| // We leave some room for extra stuff like PLT stubs. |
| TrampLimit uint64 |
| |
| Androiddynld string |
| Linuxdynld 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 |
| // are padded with zeros. |
| CodePad []byte |
| |
| // Plan 9 variables. |
| Plan9Magic uint32 |
| Plan9_64Bit bool |
| |
| Adddynrel func(*Target, *loader.Loader, *ArchSyms, loader.Sym, loader.Reloc, int) bool |
| Archinit func(*Link) |
| // Archreloc is an arch-specific hook that assists in relocation processing |
| // (invoked by 'relocsym'); it handles target-specific relocation tasks. |
| // Here "rel" is the current relocation being examined, "sym" is the symbol |
| // containing the chunk of data to which the relocation applies, and "off" |
| // 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, |
| // etc.), and a boolean indicating success/failure (a failing value indicates |
| // a fatal error). |
| Archreloc func(*Target, *loader.Loader, *ArchSyms, loader.Reloc, loader.Sym, |
| int64) (relocatedOffset int64, nExtReloc int, ok bool) |
| // Archrelocvariant is a second arch-specific hook used for |
| // relocation processing; it handles relocations where r.Type is |
| // insufficient to describe the relocation (r.Variant != |
| // sym.RV_NONE). Here "rel" is the relocation being applied, "sym" |
| // is the symbol containing the chunk of data to which the |
| // relocation applies, and "off" is the contents of the |
| // to-be-relocated data item (from sym.P). Return is an updated |
| // offset value. |
| Archrelocvariant func(target *Target, ldr *loader.Loader, rel loader.Reloc, |
| rv sym.RelocVariant, sym loader.Sym, offset int64, data []byte) (relocatedOffset int64) |
| |
| // Generate a trampoline for a call from s to rs if necessary. ri is |
| // index of the relocation. |
| Trampoline func(ctxt *Link, ldr *loader.Loader, ri int, rs, s loader.Sym) |
| |
| // Assembling the binary breaks into two phases, writing the code/data/ |
| // dwarf information (which is rather generic), and some more architecture |
| // specific work like setting up the elf headers/dynamic relocations, etc. |
| // The phases are called "Asmb" and "Asmb2". Asmb2 needs to be defined for |
| // every architecture, but only if architecture has an Asmb function will |
| // it be used for assembly. Otherwise a generic assembly Asmb function is |
| // used. |
| Asmb func(*Link, *loader.Loader) |
| Asmb2 func(*Link, *loader.Loader) |
| |
| // Extreloc is an arch-specific hook that converts a Go relocation to an |
| // external relocation. Return the external relocation and whether it is |
| // 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. |
| PEreloc1 func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool |
| Xcoffreloc1 func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool |
| |
| // Generate additional symbols for the native symbol table just prior to |
| // code generation. |
| GenSymsLate func(*Link, *loader.Loader) |
| |
| // TLSIEtoLE converts a TLS Initial Executable relocation to |
| // a TLS Local Executable relocation. |
| // |
| // This is possible when a TLS IE relocation refers to a local |
| // symbol in an executable, which is typical when internally |
| // linking PIE binaries. |
| TLSIEtoLE func(P []byte, off, size int) |
| |
| // 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) |
| } |
| |
| var ( |
| thearch Arch |
| lcSize int32 |
| rpath Rpath |
| spSize int32 |
| symSize int32 |
| ) |
| |
| const ( |
| MINFUNC = 16 // minimum size for a function |
| ) |
| |
| // Symbol version of ABIInternal symbols. It is sym.SymVerABIInternal if ABI wrappers |
| // are used, 0 otherwise. |
| var abiInternalVer = sym.SymVerABIInternal |
| |
| // DynlinkingGo reports whether we are producing Go code that can live |
| // in separate shared libraries linked together at runtime. |
| func (ctxt *Link) DynlinkingGo() bool { |
| if !ctxt.Loaded { |
| panic("DynlinkingGo called before all symbols loaded") |
| } |
| return ctxt.BuildMode == BuildModeShared || ctxt.linkShared || ctxt.BuildMode == BuildModePlugin || ctxt.canUsePlugins |
| } |
| |
| // CanUsePlugins reports whether a plugins can be used |
| func (ctxt *Link) CanUsePlugins() bool { |
| if !ctxt.Loaded { |
| panic("CanUsePlugins called before all symbols loaded") |
| } |
| return ctxt.canUsePlugins |
| } |
| |
| // NeedCodeSign reports whether we need to code-sign the output binary. |
| func (ctxt *Link) NeedCodeSign() bool { |
| return ctxt.IsDarwin() && ctxt.IsARM64() |
| } |
| |
| var ( |
| dynlib []string |
| ldflag []string |
| havedynamic int |
| Funcalign int |
| iscgo bool |
| elfglobalsymndx int |
| interpreter string |
| |
| debug_s bool // backup old value of debug['s'] |
| HEADR int32 |
| |
| nerrors int |
| liveness int64 // size of liveness data (funcdata), printed if -v |
| |
| // See -strictdups command line flag. |
| checkStrictDups int // 0=off 1=warning 2=error |
| strictDupMsgCount int |
| ) |
| |
| var ( |
| Segtext sym.Segment |
| Segrodata sym.Segment |
| Segrelrodata sym.Segment |
| Segdata sym.Segment |
| Segdwarf sym.Segment |
| |
| Segments = []*sym.Segment{&Segtext, &Segrodata, &Segrelrodata, &Segdata, &Segdwarf} |
| ) |
| |
| const pkgdef = "__.PKGDEF" |
| |
| var ( |
| // externalobj is set to true if we see an object compiled by |
| // the host compiler that is not from a package that is known |
| // to support internal linking mode. |
| externalobj = false |
| |
| // unknownObjFormat is set to true if we see an object whose |
| // format we don't recognize. |
| unknownObjFormat = false |
| |
| theline string |
| ) |
| |
| func Lflag(ctxt *Link, arg string) { |
| ctxt.Libdir = append(ctxt.Libdir, arg) |
| } |
| |
| /* |
| * Unix doesn't like it when we write to a running (or, sometimes, |
| * recently run) binary, so remove the output file before writing it. |
| * On Windows 7, remove() can force a subsequent create() to fail. |
| * S_ISREG() does not exist on Plan 9. |
| */ |
| func mayberemoveoutfile() { |
| if fi, err := os.Lstat(*flagOutfile); err == nil && !fi.Mode().IsRegular() { |
| return |
| } |
| os.Remove(*flagOutfile) |
| } |
| |
| func libinit(ctxt *Link) { |
| Funcalign = thearch.Funcalign |
| |
| // add goroot to the end of the libdir list. |
| suffix := "" |
| |
| suffixsep := "" |
| if *flagInstallSuffix != "" { |
| suffixsep = "_" |
| suffix = *flagInstallSuffix |
| } else if *flagRace { |
| suffixsep = "_" |
| suffix = "race" |
| } else if *flagMsan { |
| suffixsep = "_" |
| suffix = "msan" |
| } else if *flagAsan { |
| suffixsep = "_" |
| suffix = "asan" |
| } |
| |
| Lflag(ctxt, filepath.Join(buildcfg.GOROOT, "pkg", fmt.Sprintf("%s_%s%s%s", buildcfg.GOOS, buildcfg.GOARCH, suffixsep, suffix))) |
| |
| mayberemoveoutfile() |
| |
| if err := ctxt.Out.Open(*flagOutfile); err != nil { |
| Exitf("cannot create %s: %v", *flagOutfile, err) |
| } |
| |
| if *flagEntrySymbol == "" { |
| switch ctxt.BuildMode { |
| case BuildModeCShared, BuildModeCArchive: |
| *flagEntrySymbol = fmt.Sprintf("_rt0_%s_%s_lib", buildcfg.GOARCH, buildcfg.GOOS) |
| case BuildModeExe, BuildModePIE: |
| *flagEntrySymbol = fmt.Sprintf("_rt0_%s_%s", buildcfg.GOARCH, buildcfg.GOOS) |
| case BuildModeShared, BuildModePlugin: |
| // No *flagEntrySymbol for -buildmode=shared and plugin |
| default: |
| Errorf(nil, "unknown *flagEntrySymbol for buildmode %v", ctxt.BuildMode) |
| } |
| } |
| } |
| |
| func exitIfErrors() { |
| if nerrors != 0 || checkStrictDups > 1 && strictDupMsgCount > 0 { |
| mayberemoveoutfile() |
| Exit(2) |
| } |
| |
| } |
| |
| func errorexit() { |
| exitIfErrors() |
| Exit(0) |
| } |
| |
| func loadinternal(ctxt *Link, name string) *sym.Library { |
| zerofp := goobj.FingerprintType{} |
| if ctxt.linkShared && ctxt.PackageShlib != nil { |
| if shlib := ctxt.PackageShlib[name]; shlib != "" { |
| return addlibpath(ctxt, "internal", "internal", "", name, shlib, zerofp) |
| } |
| } |
| if ctxt.PackageFile != nil { |
| if pname := ctxt.PackageFile[name]; pname != "" { |
| return addlibpath(ctxt, "internal", "internal", pname, name, "", zerofp) |
| } |
| ctxt.Logf("loadinternal: cannot find %s\n", name) |
| return nil |
| } |
| |
| for _, libdir := range ctxt.Libdir { |
| if ctxt.linkShared { |
| shlibname := filepath.Join(libdir, name+".shlibname") |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("searching for %s.a in %s\n", name, shlibname) |
| } |
| if _, err := os.Stat(shlibname); err == nil { |
| return addlibpath(ctxt, "internal", "internal", "", name, shlibname, zerofp) |
| } |
| } |
| pname := filepath.Join(libdir, name+".a") |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("searching for %s.a in %s\n", name, pname) |
| } |
| if _, err := os.Stat(pname); err == nil { |
| return addlibpath(ctxt, "internal", "internal", pname, name, "", zerofp) |
| } |
| } |
| |
| ctxt.Logf("warning: unable to find %s.a\n", name) |
| return nil |
| } |
| |
| // extld returns the current external linker. |
| func (ctxt *Link) extld() []string { |
| if len(flagExtld) == 0 { |
| flagExtld = []string{"gcc"} |
| } |
| return flagExtld |
| } |
| |
| // findLibPathCmd uses cmd command to find gcc library libname. |
| // It returns library full path if found, or "none" if not found. |
| func (ctxt *Link) findLibPathCmd(cmd, libname string) string { |
| extld := ctxt.extld() |
| name, args := extld[0], extld[1:] |
| args = append(args, hostlinkArchArgs(ctxt.Arch)...) |
| args = append(args, cmd) |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%s %v\n", extld, args) |
| } |
| out, err := exec.Command(name, args...).Output() |
| if err != nil { |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("not using a %s file because compiler failed\n%v\n%s\n", libname, err, out) |
| } |
| return "none" |
| } |
| return strings.TrimSpace(string(out)) |
| } |
| |
| // findLibPath searches for library libname. |
| // It returns library full path if found, or "none" if not found. |
| func (ctxt *Link) findLibPath(libname string) string { |
| return ctxt.findLibPathCmd("--print-file-name="+libname, libname) |
| } |
| |
| func (ctxt *Link) loadlib() { |
| var flags uint32 |
| switch *FlagStrictDups { |
| case 0: |
| // nothing to do |
| case 1, 2: |
| flags |= loader.FlagStrictDups |
| 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.ErrorReporter.SymName = func(s loader.Sym) string { |
| return ctxt.loader.SymName(s) |
| } |
| |
| // ctxt.Library grows during the loop, so not a range loop. |
| i := 0 |
| for ; i < len(ctxt.Library); i++ { |
| lib := ctxt.Library[i] |
| if lib.Shlib == "" { |
| if ctxt.Debugvlog > 1 { |
| ctxt.Logf("autolib: %s (from %s)\n", lib.File, lib.Objref) |
| } |
| loadobjfile(ctxt, lib) |
| } |
| } |
| |
| // load internal packages, if not already |
| if *flagRace { |
| loadinternal(ctxt, "runtime/race") |
| } |
| if *flagMsan { |
| loadinternal(ctxt, "runtime/msan") |
| } |
| if *flagAsan { |
| loadinternal(ctxt, "runtime/asan") |
| } |
| loadinternal(ctxt, "runtime") |
| for ; i < len(ctxt.Library); i++ { |
| lib := ctxt.Library[i] |
| if lib.Shlib == "" { |
| loadobjfile(ctxt, lib) |
| } |
| } |
| // At this point, the Go objects are "preloaded". Not all the symbols are |
| // added to the symbol table (only defined package symbols are). Looking |
| // up symbol by name may not get expected result. |
| |
| iscgo = ctxt.LibraryByPkg["runtime/cgo"] != nil |
| |
| // Plugins a require cgo support to function. Similarly, plugins may require additional |
| // internal linker support on some platforms which may not be implemented. |
| ctxt.canUsePlugins = ctxt.LibraryByPkg["plugin"] != nil && iscgo |
| |
| // We now have enough information to determine the link mode. |
| determineLinkMode(ctxt) |
| |
| if ctxt.LinkMode == LinkExternal && !iscgo && !(buildcfg.GOOS == "darwin" && ctxt.BuildMode != BuildModePlugin && ctxt.Arch.Family == sys.AMD64) { |
| // This indicates a user requested -linkmode=external. |
| // The startup code uses an import of runtime/cgo to decide |
| // whether to initialize the TLS. So give it one. This could |
| // be handled differently but it's an unusual case. |
| if lib := loadinternal(ctxt, "runtime/cgo"); lib != nil && lib.Shlib == "" { |
| if ctxt.BuildMode == BuildModeShared || ctxt.linkShared { |
| Exitf("cannot implicitly include runtime/cgo in a shared library") |
| } |
| for ; i < len(ctxt.Library); i++ { |
| lib := ctxt.Library[i] |
| if lib.Shlib == "" { |
| loadobjfile(ctxt, lib) |
| } |
| } |
| } |
| } |
| |
| // Add non-package symbols and references of externally defined symbols. |
| ctxt.loader.LoadSyms(ctxt.Arch) |
| |
| // Load symbols from shared libraries, after all Go object symbols are loaded. |
| for _, lib := range ctxt.Library { |
| if lib.Shlib != "" { |
| if ctxt.Debugvlog > 1 { |
| ctxt.Logf("autolib: %s (from %s)\n", lib.Shlib, lib.Objref) |
| } |
| ldshlibsyms(ctxt, lib.Shlib) |
| } |
| } |
| |
| // Process cgo directives (has to be done before host object loading). |
| ctxt.loadcgodirectives() |
| |
| // Conditionally load host objects, or setup for external linking. |
| hostobjs(ctxt) |
| hostlinksetup(ctxt) |
| |
| if ctxt.LinkMode == LinkInternal && len(hostobj) != 0 { |
| // If we have any undefined symbols in external |
| // objects, try to read them from the libgcc file. |
| any := false |
| undefs := ctxt.loader.UndefinedRelocTargets(1) |
| if len(undefs) > 0 { |
| any = true |
| } |
| if any { |
| if *flagLibGCC == "" { |
| *flagLibGCC = ctxt.findLibPathCmd("--print-libgcc-file-name", "libgcc") |
| } |
| if runtime.GOOS == "openbsd" && *flagLibGCC == "libgcc.a" { |
| // On OpenBSD `clang --print-libgcc-file-name` returns "libgcc.a". |
| // In this case we fail to load libgcc.a and can encounter link |
| // errors - see if we can find libcompiler_rt.a instead. |
| *flagLibGCC = ctxt.findLibPathCmd("--print-file-name=libcompiler_rt.a", "libcompiler_rt") |
| } |
| if ctxt.HeadType == objabi.Hwindows { |
| if p := ctxt.findLibPath("libmingwex.a"); p != "none" { |
| hostArchive(ctxt, p) |
| } |
| if p := ctxt.findLibPath("libmingw32.a"); p != "none" { |
| hostArchive(ctxt, p) |
| } |
| // Link libmsvcrt.a to resolve '__acrt_iob_func' symbol |
| // (see https://golang.org/issue/23649 for details). |
| if p := ctxt.findLibPath("libmsvcrt.a"); p != "none" { |
| hostArchive(ctxt, p) |
| } |
| // 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: |
| /* |
| for: |
| #cgo windows LDFLAGS: -lmsvcrt -lm |
| import: |
| libmsvcrt.a libm.a |
| */ |
| } |
| if *flagLibGCC != "none" { |
| hostArchive(ctxt, *flagLibGCC) |
| } |
| } |
| } |
| |
| // We've loaded all the code now. |
| ctxt.Loaded = true |
| |
| importcycles() |
| |
| strictDupMsgCount = ctxt.loader.NStrictDupMsgs() |
| } |
| |
| // loadcgodirectives reads the previously discovered cgo directives, creating |
| // symbols in preparation for host object loading or use later in the link. |
| func (ctxt *Link) loadcgodirectives() { |
| l := ctxt.loader |
| hostObjSyms := make(map[loader.Sym]struct{}) |
| for _, d := range ctxt.cgodata { |
| setCgoAttr(ctxt, d.file, d.pkg, d.directives, hostObjSyms) |
| } |
| ctxt.cgodata = nil |
| |
| if ctxt.LinkMode == LinkInternal { |
| // Drop all the cgo_import_static declarations. |
| // Turns out we won't be needing them. |
| for symIdx := range hostObjSyms { |
| if l.SymType(symIdx) == sym.SHOSTOBJ { |
| // If a symbol was marked both |
| // cgo_import_static and cgo_import_dynamic, |
| // then we want to make it cgo_import_dynamic |
| // now. |
| su := l.MakeSymbolUpdater(symIdx) |
| if l.SymExtname(symIdx) != "" && l.SymDynimplib(symIdx) != "" && !(l.AttrCgoExportStatic(symIdx) || l.AttrCgoExportDynamic(symIdx)) { |
| su.SetType(sym.SDYNIMPORT) |
| } else { |
| su.SetType(0) |
| } |
| } |
| } |
| } |
| } |
| |
| // Set up flags and special symbols depending on the platform build mode. |
| // This version works with loader.Loader. |
| func (ctxt *Link) linksetup() { |
| switch ctxt.BuildMode { |
| case BuildModeCShared, BuildModePlugin: |
| symIdx := ctxt.loader.LookupOrCreateSym("runtime.islibrary", 0) |
| sb := ctxt.loader.MakeSymbolUpdater(symIdx) |
| sb.SetType(sym.SNOPTRDATA) |
| sb.AddUint8(1) |
| case BuildModeCArchive: |
| symIdx := ctxt.loader.LookupOrCreateSym("runtime.isarchive", 0) |
| sb := ctxt.loader.MakeSymbolUpdater(symIdx) |
| sb.SetType(sym.SNOPTRDATA) |
| sb.AddUint8(1) |
| } |
| |
| // Recalculate pe parameters now that we have ctxt.LinkMode set. |
| if ctxt.HeadType == objabi.Hwindows { |
| Peinit(ctxt) |
| } |
| |
| if ctxt.LinkMode == LinkExternal { |
| // When external linking, we are creating an object file. The |
| // absolute address is irrelevant. |
| *FlagTextAddr = 0 |
| } |
| |
| // If there are no dynamic libraries needed, gcc disables dynamic linking. |
| // Because of this, glibc's dynamic ELF loader occasionally (like in version 2.13) |
| // assumes that a dynamic binary always refers to at least one dynamic library. |
| // Rather than be a source of test cases for glibc, disable dynamic linking |
| // the same way that gcc would. |
| // |
| // Exception: on OS X, programs such as Shark only work with dynamic |
| // binaries, so leave it enabled on OS X (Mach-O) binaries. |
| // Also leave it enabled on Solaris which doesn't support |
| // statically linked binaries. |
| if ctxt.BuildMode == BuildModeExe { |
| if havedynamic == 0 && ctxt.HeadType != objabi.Hdarwin && ctxt.HeadType != objabi.Hsolaris { |
| *FlagD = true |
| } |
| } |
| |
| if ctxt.LinkMode == LinkExternal && ctxt.Arch.Family == sys.PPC64 && buildcfg.GOOS != "aix" { |
| toc := ctxt.loader.LookupOrCreateSym(".TOC.", 0) |
| sb := ctxt.loader.MakeSymbolUpdater(toc) |
| sb.SetType(sym.SDYNIMPORT) |
| } |
| |
| // The Android Q linker started to complain about underalignment of the our TLS |
| // section. We don't actually use the section on android, so don't |
| // generate it. |
| if buildcfg.GOOS != "android" { |
| tlsg := ctxt.loader.LookupOrCreateSym("runtime.tlsg", 0) |
| sb := ctxt.loader.MakeSymbolUpdater(tlsg) |
| |
| // runtime.tlsg is used for external linking on platforms that do not define |
| // a variable to hold g in assembly (currently only intel). |
| if sb.Type() == 0 { |
| sb.SetType(sym.STLSBSS) |
| sb.SetSize(int64(ctxt.Arch.PtrSize)) |
| } else if sb.Type() != sym.SDYNIMPORT { |
| Errorf(nil, "runtime declared tlsg variable %v", sb.Type()) |
| } |
| ctxt.loader.SetAttrReachable(tlsg, true) |
| ctxt.Tlsg = tlsg |
| } |
| |
| var moduledata loader.Sym |
| var mdsb *loader.SymbolBuilder |
| if ctxt.BuildMode == BuildModePlugin { |
| moduledata = ctxt.loader.LookupOrCreateSym("local.pluginmoduledata", 0) |
| mdsb = ctxt.loader.MakeSymbolUpdater(moduledata) |
| ctxt.loader.SetAttrLocal(moduledata, true) |
| } else { |
| moduledata = ctxt.loader.LookupOrCreateSym("runtime.firstmoduledata", 0) |
| mdsb = ctxt.loader.MakeSymbolUpdater(moduledata) |
| } |
| if mdsb.Type() != 0 && mdsb.Type() != sym.SDYNIMPORT { |
| // If the module (toolchain-speak for "executable or shared |
| // library") we are linking contains the runtime package, it |
| // will define the runtime.firstmoduledata symbol and we |
| // truncate it back to 0 bytes so we can define its entire |
| // contents in symtab.go:symtab(). |
| mdsb.SetSize(0) |
| |
| // In addition, on ARM, the runtime depends on the linker |
| // recording the value of GOARM. |
| if ctxt.Arch.Family == sys.ARM { |
| goarm := ctxt.loader.LookupOrCreateSym("runtime.goarm", 0) |
| sb := ctxt.loader.MakeSymbolUpdater(goarm) |
| sb.SetType(sym.SDATA) |
| sb.SetSize(0) |
| sb.AddUint8(uint8(buildcfg.GOARM)) |
| } |
| |
| // Set runtime.disableMemoryProfiling bool if |
| // runtime.MemProfile is not retained in the binary after |
| // deadcode (and we're not dynamically linking). |
| memProfile := ctxt.loader.Lookup("runtime.MemProfile", abiInternalVer) |
| if memProfile != 0 && !ctxt.loader.AttrReachable(memProfile) && !ctxt.DynlinkingGo() { |
| memProfSym := ctxt.loader.LookupOrCreateSym("runtime.disableMemoryProfiling", 0) |
| sb := ctxt.loader.MakeSymbolUpdater(memProfSym) |
| sb.SetType(sym.SDATA) |
| sb.SetSize(0) |
| sb.AddUint8(1) // true bool |
| } |
| } else { |
| // If OTOH the module does not contain the runtime package, |
| // create a local symbol for the moduledata. |
| moduledata = ctxt.loader.LookupOrCreateSym("local.moduledata", 0) |
| mdsb = ctxt.loader.MakeSymbolUpdater(moduledata) |
| ctxt.loader.SetAttrLocal(moduledata, true) |
| } |
| // In all cases way we mark the moduledata as noptrdata to hide it from |
| // the GC. |
| mdsb.SetType(sym.SNOPTRDATA) |
| ctxt.loader.SetAttrReachable(moduledata, true) |
| ctxt.Moduledata = moduledata |
| |
| if ctxt.Arch == sys.Arch386 && ctxt.HeadType != objabi.Hwindows { |
| if (ctxt.BuildMode == BuildModeCArchive && ctxt.IsELF) || ctxt.BuildMode == BuildModeCShared || ctxt.BuildMode == BuildModePIE || ctxt.DynlinkingGo() { |
| got := ctxt.loader.LookupOrCreateSym("_GLOBAL_OFFSET_TABLE_", 0) |
| sb := ctxt.loader.MakeSymbolUpdater(got) |
| sb.SetType(sym.SDYNIMPORT) |
| ctxt.loader.SetAttrReachable(got, true) |
| } |
| } |
| |
| // DWARF-gen and other phases require that the unit Textp slices |
| // be populated, so that it can walk the functions in each unit. |
| // Call into the loader to do this (requires that we collect the |
| // set of internal libraries first). NB: might be simpler if we |
| // moved isRuntimeDepPkg to cmd/internal and then did the test in |
| // loader.AssignTextSymbolOrder. |
| ctxt.Library = postorder(ctxt.Library) |
| intlibs := []bool{} |
| for _, lib := range ctxt.Library { |
| intlibs = append(intlibs, isRuntimeDepPkg(lib.Pkg)) |
| } |
| ctxt.Textp = ctxt.loader.AssignTextSymbolOrder(ctxt.Library, intlibs, ctxt.Textp) |
| } |
| |
| // mangleTypeSym shortens the names of symbols that represent Go types |
| // if they are visible in the symbol table. |
| // |
| // As the names of these symbols are derived from the string of |
| // the type, they can run to many kilobytes long. So we shorten |
| // them using a SHA-1 when the name appears in the final binary. |
| // This also removes characters that upset external linkers. |
| // |
| // These are the symbols that begin with the prefix 'type.' and |
| // contain run-time type information used by the runtime and reflect |
| // packages. All Go binaries contain these symbols, but only |
| // those programs loaded dynamically in multiple parts need these |
| // symbols to have entries in the symbol table. |
| func (ctxt *Link) mangleTypeSym() { |
| if ctxt.BuildMode != BuildModeShared && !ctxt.linkShared && ctxt.BuildMode != BuildModePlugin && !ctxt.CanUsePlugins() { |
| return |
| } |
| |
| ldr := ctxt.loader |
| for s := loader.Sym(1); s < loader.Sym(ldr.NSym()); s++ { |
| if !ldr.AttrReachable(s) && !ctxt.linkShared { |
| // If -linkshared, the GCProg generation code may need to reach |
| // out to the shared library for the type descriptor's data, even |
| // the type descriptor itself is not actually needed at run time |
| // (therefore not reachable). We still need to mangle its name, |
| // so it is consistent with the one stored in the shared library. |
| continue |
| } |
| name := ldr.SymName(s) |
| newName := typeSymbolMangle(name) |
| if newName != name { |
| ldr.SetSymExtname(s, newName) |
| |
| // When linking against a shared library, the Go object file may |
| // have reference to the original symbol name whereas the shared |
| // library provides a symbol with the mangled name. We need to |
| // copy the payload of mangled to original. |
| // XXX maybe there is a better way to do this. |
| dup := ldr.Lookup(newName, ldr.SymVersion(s)) |
| if dup != 0 { |
| st := ldr.SymType(s) |
| dt := ldr.SymType(dup) |
| if st == sym.Sxxx && dt != sym.Sxxx { |
| ldr.CopySym(dup, s) |
| } |
| } |
| } |
| } |
| } |
| |
| // typeSymbolMangle mangles the given symbol name into something shorter. |
| // |
| // Keep the type.. prefix, which parts of the linker (like the |
| // DWARF generator) know means the symbol is not decodable. |
| // Leave type.runtime. symbols alone, because other parts of |
| // the linker manipulates them. |
| func typeSymbolMangle(name string) string { |
| if !strings.HasPrefix(name, "type.") { |
| return name |
| } |
| if strings.HasPrefix(name, "type.runtime.") { |
| return name |
| } |
| if len(name) <= 14 && !strings.Contains(name, "@") { // Issue 19529 |
| return name |
| } |
| hash := sha1.Sum([]byte(name)) |
| prefix := "type." |
| if name[5] == '.' { |
| prefix = "type.." |
| } |
| return prefix + base64.StdEncoding.EncodeToString(hash[:6]) |
| } |
| |
| /* |
| * look for the next file in an archive. |
| * adapted from libmach. |
| */ |
| func nextar(bp *bio.Reader, off int64, a *ArHdr) int64 { |
| if off&1 != 0 { |
| off++ |
| } |
| bp.MustSeek(off, 0) |
| var buf [SAR_HDR]byte |
| if n, err := io.ReadFull(bp, buf[:]); err != nil { |
| if n == 0 && err != io.EOF { |
| return -1 |
| } |
| return 0 |
| } |
| |
| a.name = artrim(buf[0:16]) |
| a.date = artrim(buf[16:28]) |
| a.uid = artrim(buf[28:34]) |
| a.gid = artrim(buf[34:40]) |
| a.mode = artrim(buf[40:48]) |
| a.size = artrim(buf[48:58]) |
| a.fmag = artrim(buf[58:60]) |
| |
| arsize := atolwhex(a.size) |
| if arsize&1 != 0 { |
| arsize++ |
| } |
| return arsize + SAR_HDR |
| } |
| |
| func loadobjfile(ctxt *Link, lib *sym.Library) { |
| pkg := objabi.PathToPrefix(lib.Pkg) |
| |
| if ctxt.Debugvlog > 1 { |
| ctxt.Logf("ldobj: %s (%s)\n", lib.File, pkg) |
| } |
| f, err := bio.Open(lib.File) |
| if err != nil { |
| Exitf("cannot open file %s: %v", lib.File, err) |
| } |
| defer f.Close() |
| defer func() { |
| if pkg == "main" && !lib.Main { |
| Exitf("%s: not package main", lib.File) |
| } |
| }() |
| |
| for i := 0; i < len(ARMAG); i++ { |
| if c, err := f.ReadByte(); err == nil && c == ARMAG[i] { |
| continue |
| } |
| |
| /* load it as a regular file */ |
| l := f.MustSeek(0, 2) |
| f.MustSeek(0, 0) |
| ldobj(ctxt, f, lib, l, lib.File, lib.File) |
| return |
| } |
| |
| /* |
| * load all the object files from the archive now. |
| * this gives us sequential file access and keeps us |
| * from needing to come back later to pick up more |
| * objects. it breaks the usual C archive model, but |
| * this is Go, not C. the common case in Go is that |
| * we need to load all the objects, and then we throw away |
| * the individual symbols that are unused. |
| * |
| * loading every object will also make it possible to |
| * load foreign objects not referenced by __.PKGDEF. |
| */ |
| var arhdr ArHdr |
| off := f.Offset() |
| for { |
| l := nextar(f, off, &arhdr) |
| if l == 0 { |
| break |
| } |
| if l < 0 { |
| Exitf("%s: malformed archive", lib.File) |
| } |
| off += l |
| |
| // __.PKGDEF isn't a real Go object file, and it's |
| // absent in -linkobj builds anyway. Skipping it |
| // ensures consistency between -linkobj and normal |
| // build modes. |
| if arhdr.name == pkgdef { |
| continue |
| } |
| |
| // Skip other special (non-object-file) sections that |
| // build tools may have added. Such sections must have |
| // short names so that the suffix is not truncated. |
| if len(arhdr.name) < 16 { |
| if ext := filepath.Ext(arhdr.name); ext != ".o" && ext != ".syso" { |
| continue |
| } |
| } |
| |
| pname := fmt.Sprintf("%s(%s)", lib.File, arhdr.name) |
| l = atolwhex(arhdr.size) |
| ldobj(ctxt, f, lib, l, pname, lib.File) |
| } |
| } |
| |
| type Hostobj struct { |
| ld func(*Link, *bio.Reader, string, int64, string) |
| pkg string |
| pn string |
| file string |
| off int64 |
| length int64 |
| } |
| |
| var hostobj []Hostobj |
| |
| // These packages can use internal linking mode. |
| // Others trigger external mode. |
| var internalpkg = []string{ |
| "crypto/x509", |
| "net", |
| "os/user", |
| "runtime/cgo", |
| "runtime/race", |
| "runtime/msan", |
| "runtime/asan", |
| } |
| |
| func ldhostobj(ld func(*Link, *bio.Reader, string, int64, string), headType objabi.HeadType, f *bio.Reader, pkg string, length int64, pn string, file string) *Hostobj { |
| isinternal := false |
| for _, intpkg := range internalpkg { |
| if pkg == intpkg { |
| isinternal = true |
| break |
| } |
| } |
| |
| // DragonFly declares errno with __thread, which results in a symbol |
| // type of R_386_TLS_GD or R_X86_64_TLSGD. The Go linker does not |
| // currently know how to handle TLS relocations, hence we have to |
| // force external linking for any libraries that link in code that |
| // uses errno. This can be removed if the Go linker ever supports |
| // these relocation types. |
| if headType == objabi.Hdragonfly { |
| if pkg == "net" || pkg == "os/user" { |
| isinternal = false |
| } |
| } |
| |
| if !isinternal { |
| externalobj = true |
| } |
| |
| hostobj = append(hostobj, Hostobj{}) |
| h := &hostobj[len(hostobj)-1] |
| h.ld = ld |
| h.pkg = pkg |
| h.pn = pn |
| h.file = file |
| h.off = f.Offset() |
| h.length = length |
| return h |
| } |
| |
| func hostobjs(ctxt *Link) { |
| if ctxt.LinkMode != LinkInternal { |
| return |
| } |
| var h *Hostobj |
| |
| for i := 0; i < len(hostobj); i++ { |
| h = &hostobj[i] |
| f, err := bio.Open(h.file) |
| if err != nil { |
| Exitf("cannot reopen %s: %v", h.pn, err) |
| } |
| |
| f.MustSeek(h.off, 0) |
| if h.ld == nil { |
| Errorf(nil, "%s: unrecognized object file format", h.pn) |
| continue |
| } |
| h.ld(ctxt, f, h.pkg, h.length, h.pn) |
| f.Close() |
| } |
| } |
| |
| func hostlinksetup(ctxt *Link) { |
| if ctxt.LinkMode != LinkExternal { |
| return |
| } |
| |
| // For external link, record that we need to tell the external linker -s, |
| // and turn off -s internally: the external linker needs the symbol |
| // information for its final link. |
| debug_s = *FlagS |
| *FlagS = false |
| |
| // create temporary directory and arrange cleanup |
| if *flagTmpdir == "" { |
| dir, err := ioutil.TempDir("", "go-link-") |
| if err != nil { |
| log.Fatal(err) |
| } |
| *flagTmpdir = dir |
| ownTmpDir = true |
| AtExit(func() { |
| os.RemoveAll(*flagTmpdir) |
| }) |
| } |
| |
| // change our output to temporary object file |
| if err := ctxt.Out.Close(); err != nil { |
| Exitf("error closing output file") |
| } |
| mayberemoveoutfile() |
| |
| p := filepath.Join(*flagTmpdir, "go.o") |
| if err := ctxt.Out.Open(p); err != nil { |
| Exitf("cannot create %s: %v", p, err) |
| } |
| } |
| |
| // hostobjCopy creates a copy of the object files in hostobj in a |
| // temporary directory. |
| func 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) |
| |
| wg.Add(1) |
| go func() { |
| sema <- struct{}{} |
| defer func() { |
| <-sema |
| wg.Done() |
| }() |
| f, err := os.Open(h.file) |
| if err != nil { |
| Exitf("cannot reopen %s: %v", h.pn, err) |
| } |
| defer f.Close() |
| if _, err := f.Seek(h.off, 0); err != nil { |
| Exitf("cannot seek %s: %v", h.pn, err) |
| } |
| |
| w, err := os.Create(dst) |
| if err != nil { |
| Exitf("cannot create %s: %v", dst, err) |
| } |
| if _, err := io.CopyN(w, f, h.length); err != nil { |
| Exitf("cannot write %s: %v", dst, err) |
| } |
| if err := w.Close(); err != nil { |
| Exitf("cannot close %s: %v", dst, err) |
| } |
| }() |
| } |
| wg.Wait() |
| return paths |
| } |
| |
| // writeGDBLinkerScript creates gcc linker script file in temp |
| // directory. writeGDBLinkerScript returns created file path. |
| // The script is used to work around gcc bug |
| // (see https://golang.org/issue/20183 for details). |
| func writeGDBLinkerScript() string { |
| name := "fix_debug_gdb_scripts.ld" |
| path := filepath.Join(*flagTmpdir, name) |
| src := `SECTIONS |
| { |
| .debug_gdb_scripts BLOCK(__section_alignment__) (NOLOAD) : |
| { |
| *(.debug_gdb_scripts) |
| } |
| } |
| INSERT AFTER .debug_types; |
| ` |
| err := ioutil.WriteFile(path, []byte(src), 0666) |
| if err != nil { |
| Errorf(nil, "WriteFile %s failed: %v", name, err) |
| } |
| return path |
| } |
| |
| // archive builds a .a archive from the hostobj object files. |
| func (ctxt *Link) archive() { |
| if ctxt.BuildMode != BuildModeCArchive { |
| return |
| } |
| |
| exitIfErrors() |
| |
| if *flagExtar == "" { |
| *flagExtar = "ar" |
| } |
| |
| mayberemoveoutfile() |
| |
| // Force the buffer to flush here so that external |
| // tools will see a complete file. |
| if err := ctxt.Out.Close(); err != nil { |
| Exitf("error closing %v", *flagOutfile) |
| } |
| |
| argv := []string{*flagExtar, "-q", "-c", "-s"} |
| if ctxt.HeadType == objabi.Haix { |
| argv = append(argv, "-X64") |
| } |
| argv = append(argv, *flagOutfile) |
| argv = append(argv, filepath.Join(*flagTmpdir, "go.o")) |
| argv = append(argv, hostobjCopy()...) |
| |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("archive: %s\n", strings.Join(argv, " ")) |
| } |
| |
| // If supported, use syscall.Exec() to invoke the archive command, |
| // which should be the final remaining step needed for the link. |
| // This will reduce peak RSS for the link (and speed up linking of |
| // large applications), since when the archive command runs we |
| // won't be holding onto all of the linker's live memory. |
| if syscallExecSupported && !ownTmpDir { |
| runAtExitFuncs() |
| ctxt.execArchive(argv) |
| panic("should not get here") |
| } |
| |
| // Otherwise invoke 'ar' in the usual way (fork + exec). |
| if out, err := exec.Command(argv[0], argv[1:]...).CombinedOutput(); err != nil { |
| Exitf("running %s failed: %v\n%s", argv[0], err, out) |
| } |
| } |
| |
| func (ctxt *Link) hostlink() { |
| if ctxt.LinkMode != LinkExternal || nerrors > 0 { |
| return |
| } |
| if ctxt.BuildMode == BuildModeCArchive { |
| return |
| } |
| |
| var argv []string |
| argv = append(argv, ctxt.extld()...) |
| argv = append(argv, hostlinkArchArgs(ctxt.Arch)...) |
| |
| if *FlagS || debug_s { |
| 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. |
| } 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 |
| |
| switch ctxt.HeadType { |
| case objabi.Hdarwin: |
| if combineDwarf { |
| // Leave room for DWARF combining. |
| // -headerpad is incompatible with -fembed-bitcode. |
| argv = append(argv, "-Wl,-headerpad,1144") |
| } |
| if ctxt.DynlinkingGo() && buildcfg.GOOS != "ios" { |
| // -flat_namespace is deprecated on iOS. |
| // It is useful for supporting plugins. We don't support plugins on iOS. |
| argv = append(argv, "-Wl,-flat_namespace") |
| } |
| if !combineDwarf { |
| argv = append(argv, "-Wl,-S") // suppress STAB (symbolic debugging) symbols |
| } |
| case objabi.Hopenbsd: |
| argv = append(argv, "-Wl,-nopie") |
| argv = append(argv, "-pthread") |
| case objabi.Hwindows: |
| if windowsgui { |
| argv = append(argv, "-mwindows") |
| } else { |
| argv = append(argv, "-mconsole") |
| } |
| // Mark as having awareness of terminal services, to avoid |
| // ancient compatibility hacks. |
| argv = append(argv, "-Wl,--tsaware") |
| |
| // Enable DEP |
| argv = append(argv, "-Wl,--nxcompat") |
| |
| argv = append(argv, fmt.Sprintf("-Wl,--major-os-version=%d", PeMinimumTargetMajorVersion)) |
| argv = append(argv, fmt.Sprintf("-Wl,--minor-os-version=%d", PeMinimumTargetMinorVersion)) |
| argv = append(argv, fmt.Sprintf("-Wl,--major-subsystem-version=%d", PeMinimumTargetMajorVersion)) |
| argv = append(argv, fmt.Sprintf("-Wl,--minor-subsystem-version=%d", PeMinimumTargetMinorVersion)) |
| case objabi.Haix: |
| argv = append(argv, "-pthread") |
| // prevent ld to reorder .text functions to keep the same |
| // first/last functions for moduledata. |
| argv = append(argv, "-Wl,-bnoobjreorder") |
| // mcmodel=large is needed for every gcc generated files, but |
| // ld still need -bbigtoc in order to allow larger TOC. |
| argv = append(argv, "-mcmodel=large") |
| argv = append(argv, "-Wl,-bbigtoc") |
| } |
| |
| // Enable ASLR on Windows. |
| addASLRargs := func(argv []string) []string { |
| // Enable ASLR. |
| argv = append(argv, "-Wl,--dynamicbase") |
| // enable high-entropy ASLR on 64-bit. |
| if ctxt.Arch.PtrSize >= 8 { |
| argv = append(argv, "-Wl,--high-entropy-va") |
| } |
| return argv |
| } |
| |
| switch ctxt.BuildMode { |
| case BuildModeExe: |
| if ctxt.HeadType == objabi.Hdarwin { |
| if machoPlatform == PLATFORM_MACOS && ctxt.IsAMD64() { |
| argv = append(argv, "-Wl,-no_pie") |
| argv = append(argv, "-Wl,-pagezero_size,4000000") |
| } |
| } |
| case BuildModePIE: |
| switch ctxt.HeadType { |
| case objabi.Hdarwin, objabi.Haix: |
| case objabi.Hwindows: |
| argv = addASLRargs(argv) |
| default: |
| // ELF. |
| if ctxt.UseRelro() { |
| argv = append(argv, "-Wl,-z,relro") |
| } |
| argv = append(argv, "-pie") |
| } |
| case BuildModeCShared: |
| if ctxt.HeadType == objabi.Hdarwin { |
| argv = append(argv, "-dynamiclib") |
| } else { |
| if ctxt.UseRelro() { |
| argv = append(argv, "-Wl,-z,relro") |
| } |
| argv = append(argv, "-shared") |
| if ctxt.HeadType == objabi.Hwindows { |
| if *flagAslr { |
| argv = addASLRargs(argv) |
| } |
| } else { |
| // Pass -z nodelete to mark the shared library as |
| // non-closeable: a dlclose will do nothing. |
| argv = append(argv, "-Wl,-z,nodelete") |
| // Only pass Bsymbolic on non-Windows. |
| argv = append(argv, "-Wl,-Bsymbolic") |
| } |
| } |
| case BuildModeShared: |
| if ctxt.UseRelro() { |
| argv = append(argv, "-Wl,-z,relro") |
| } |
| argv = append(argv, "-shared") |
| case BuildModePlugin: |
| if ctxt.HeadType == objabi.Hdarwin { |
| argv = append(argv, "-dynamiclib") |
| } else { |
| if ctxt.UseRelro() { |
| argv = append(argv, "-Wl,-z,relro") |
| } |
| argv = append(argv, "-shared") |
| } |
| } |
| |
| var altLinker string |
| if ctxt.IsELF && ctxt.DynlinkingGo() { |
| // We force all symbol resolution to be done at program startup |
| // because lazy PLT resolution can use large amounts of stack at |
| // times we cannot allow it to do so. |
| argv = append(argv, "-Wl,-znow") |
| |
| // Do not let the host linker generate COPY relocations. These |
| // can move symbols out of sections that rely on stable offsets |
| // from the beginning of the section (like sym.STYPE). |
| argv = append(argv, "-Wl,-znocopyreloc") |
| |
| if buildcfg.GOOS == "android" { |
| // Use lld to avoid errors from default linker (issue #38838) |
| 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. |
| // 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. |
| altLinker = "gold" |
| |
| // If gold is not installed, gcc will silently switch |
| // back to ld.bfd. So we parse the version information |
| // and provide a useful error if gold is missing. |
| name, args := flagExtld[0], flagExtld[1:] |
| args = append(args, "-fuse-ld=gold", "-Wl,--version") |
| 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) |
| } |
| } |
| } |
| } |
| if ctxt.Arch.Family == sys.ARM64 && buildcfg.GOOS == "freebsd" { |
| // Switch to ld.bfd on freebsd/arm64. |
| altLinker = "bfd" |
| |
| // Provide a useful error if ld.bfd is missing. |
| name, args := flagExtld[0], flagExtld[1:] |
| args = append(args, "-fuse-ld=bfd", "-Wl,--version") |
| cmd := exec.Command(name, args...) |
| if out, err := cmd.CombinedOutput(); err == nil { |
| if !bytes.Contains(out, []byte("GNU ld")) { |
| log.Fatalf("ARM64 external linker must be ld.bfd (issue #35197), please install devel/binutils") |
| } |
| } |
| } |
| if altLinker != "" { |
| argv = append(argv, "-fuse-ld="+altLinker) |
| } |
| |
| if ctxt.IsELF && len(buildinfo) > 0 { |
| argv = append(argv, fmt.Sprintf("-Wl,--build-id=0x%x", buildinfo)) |
| } |
| |
| // On Windows, given -o foo, GCC will append ".exe" to produce |
| // "foo.exe". We have decided that we want to honor the -o |
| // option. To make this work, we append a '.' so that GCC |
| // will decide that the file already has an extension. We |
| // only want to do this when producing a Windows output file |
| // on a Windows host. |
| outopt := *flagOutfile |
| if buildcfg.GOOS == "windows" && runtime.GOOS == "windows" && filepath.Ext(outopt) == "" { |
| outopt += "." |
| } |
| argv = append(argv, "-o") |
| argv = append(argv, outopt) |
| |
| if rpath.val != "" { |
| argv = append(argv, fmt.Sprintf("-Wl,-rpath,%s", rpath.val)) |
| } |
| |
| if *flagInterpreter != "" { |
| // Many linkers support both -I and the --dynamic-linker flags |
| // to set the ELF interpreter, but lld only supports |
| // --dynamic-linker so prefer that (ld on very old Solaris only |
| // supports -I but that seems less important). |
| argv = append(argv, fmt.Sprintf("-Wl,--dynamic-linker,%s", *flagInterpreter)) |
| } |
| |
| // Force global symbols to be exported for dlopen, etc. |
| if ctxt.IsELF { |
| argv = append(argv, "-rdynamic") |
| } |
| if ctxt.HeadType == objabi.Haix { |
| fileName := xcoffCreateExportFile(ctxt) |
| argv = append(argv, "-Wl,-bE:"+fileName) |
| } |
| |
| const unusedArguments = "-Qunused-arguments" |
| if linkerFlagSupported(ctxt.Arch, argv[0], altLinker, unusedArguments) { |
| argv = append(argv, unusedArguments) |
| } |
| |
| const compressDWARF = "-Wl,--compress-debug-sections=zlib-gnu" |
| 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()...) |
| if ctxt.HeadType == objabi.Haix { |
| // We want to have C files after Go files to remove |
| // trampolines csects made by ld. |
| argv = append(argv, "-nostartfiles") |
| argv = append(argv, "/lib/crt0_64.o") |
| |
| extld := ctxt.extld() |
| name, args := extld[0], extld[1:] |
| // Get starting files. |
| getPathFile := func(file string) string { |
| args := append(args, "-maix64", "--print-file-name="+file) |
| out, err := exec.Command(name, args...).CombinedOutput() |
| if err != nil { |
| log.Fatalf("running %s failed: %v\n%s", extld, err, out) |
| } |
| return strings.Trim(string(out), "\n") |
| } |
| // Since GCC version 11, the 64-bit version of GCC starting files |
| // are now suffixed by "_64". Even under "-maix64" multilib directory |
| // "crtcxa.o" is 32-bit. |
| crtcxa := getPathFile("crtcxa_64.o") |
| if !filepath.IsAbs(crtcxa) { |
| crtcxa = getPathFile("crtcxa.o") |
| } |
| crtdbase := getPathFile("crtdbase_64.o") |
| if !filepath.IsAbs(crtdbase) { |
| crtdbase = getPathFile("crtdbase.o") |
| } |
| argv = append(argv, crtcxa) |
| argv = append(argv, crtdbase) |
| } |
| |
| if ctxt.linkShared { |
| seenDirs := make(map[string]bool) |
| seenLibs := make(map[string]bool) |
| addshlib := func(path string) { |
| dir, base := filepath.Split(path) |
| if !seenDirs[dir] { |
| argv = append(argv, "-L"+dir) |
| if !rpath.set { |
| argv = append(argv, "-Wl,-rpath="+dir) |
| } |
| seenDirs[dir] = true |
| } |
| base = strings.TrimSuffix(base, ".so") |
| base = strings.TrimPrefix(base, "lib") |
| if !seenLibs[base] { |
| argv = append(argv, "-l"+base) |
| seenLibs[base] = true |
| } |
| } |
| for _, shlib := range ctxt.Shlibs { |
| addshlib(shlib.Path) |
| for _, dep := range shlib.Deps { |
| if dep == "" { |
| continue |
| } |
| libpath := findshlib(ctxt, dep) |
| if libpath != "" { |
| addshlib(libpath) |
| } |
| } |
| } |
| } |
| |
| // clang, unlike GCC, passes -rdynamic to the linker |
| // even when linking with -static, causing a linker |
| // error when using GNU ld. So take out -rdynamic if |
| // we added it. We do it in this order, rather than |
| // only adding -rdynamic later, so that -extldflags |
| // can override -rdynamic without using -static. |
| // Similarly for -Wl,--dynamic-linker. |
| checkStatic := func(arg string) { |
| if ctxt.IsELF && arg == "-static" { |
| for i := range argv { |
| if argv[i] == "-rdynamic" || strings.HasPrefix(argv[i], "-Wl,--dynamic-linker,") { |
| argv[i] = "-static" |
| } |
| } |
| } |
| } |
| |
| for _, p := range ldflag { |
| argv = append(argv, p) |
| checkStatic(p) |
| } |
| |
| // When building a program with the default -buildmode=exe the |
| // gc compiler generates code requires DT_TEXTREL in a |
| // position independent executable (PIE). On systems where the |
| // toolchain creates PIEs by default, and where DT_TEXTREL |
| // does not work, the resulting programs will not run. See |
| // issue #17847. To avoid this problem pass -no-pie to the |
| // toolchain if it is supported. |
| if ctxt.BuildMode == BuildModeExe && !ctxt.linkShared && !(ctxt.IsDarwin() && ctxt.IsARM64()) { |
| // GCC uses -no-pie, clang uses -nopie. |
| for _, nopie := range []string{"-no-pie", "-nopie"} { |
| if linkerFlagSupported(ctxt.Arch, argv[0], altLinker, nopie) { |
| argv = append(argv, nopie) |
| break |
| } |
| } |
| } |
| |
| for _, p := range flagExtldflags { |
| argv = append(argv, p) |
| checkStatic(p) |
| } |
| if ctxt.HeadType == objabi.Hwindows { |
| // Determine which linker we're using. Add in the extldflags in |
| // case used has specified "-fuse-ld=...". |
| extld := ctxt.extld() |
| name, args := extld[0], extld[1:] |
| args = append(args, flagExtldflags...) |
| args = append(args, "-Wl,--version") |
| cmd := exec.Command(name, args...) |
| usingLLD := false |
| if out, err := cmd.CombinedOutput(); err == nil { |
| if bytes.Contains(out, []byte("LLD ")) { |
| usingLLD = true |
| } |
| } |
| |
| // use gcc linker script to work around gcc bug |
| // (see https://golang.org/issue/20183 for details). |
| if !usingLLD { |
| p := writeGDBLinkerScript() |
| argv = append(argv, "-Wl,-T,"+p) |
| } |
| // libmingw32 and libmingwex have some inter-dependencies, |
| // so must use linker groups. |
| argv = append(argv, "-Wl,--start-group", "-lmingwex", "-lmingw32", "-Wl,--end-group") |
| argv = append(argv, peimporteddlls()...) |
| } |
| |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("host link:") |
| for _, v := range argv { |
| ctxt.Logf(" %q", v) |
| } |
| ctxt.Logf("\n") |
| } |
| |
| out, err := exec.Command(argv[0], argv[1:]...).CombinedOutput() |
| if err != nil { |
| Exitf("running %s failed: %v\n%s", argv[0], err, out) |
| } |
| |
| // Filter out useless linker warnings caused by bugs outside Go. |
| // See also cmd/go/internal/work/exec.go's gccld method. |
| var save [][]byte |
| var skipLines int |
| for _, line := range bytes.SplitAfter(out, []byte("\n")) { |
| // golang.org/issue/26073 - Apple Xcode bug |
| if bytes.Contains(line, []byte("ld: warning: text-based stub file")) { |
| continue |
| } |
| |
| if skipLines > 0 { |
| skipLines-- |
| continue |
| } |
| |
| // Remove TOC overflow warning on AIX. |
| if bytes.Contains(line, []byte("ld: 0711-783")) { |
| skipLines = 2 |
| continue |
| } |
| |
| save = append(save, line) |
| } |
| out = bytes.Join(save, nil) |
| |
| if len(out) > 0 { |
| // always print external output even if the command is successful, so that we don't |
| // swallow linker warnings (see https://golang.org/issue/17935). |
| ctxt.Logf("%s", out) |
| } |
| |
| if combineDwarf { |
| // Find "dsymutils" and "strip" tools using CC --print-prog-name. |
| var cc []string |
| cc = append(cc, ctxt.extld()...) |
| cc = append(cc, hostlinkArchArgs(ctxt.Arch)...) |
| cc = append(cc, "--print-prog-name", "dsymutil") |
| out, err := exec.Command(cc[0], cc[1:]...).CombinedOutput() |
| if err != nil { |
| Exitf("%s: finding dsymutil failed: %v\n%s", os.Args[0], err, out) |
| } |
| dsymutilCmd := strings.TrimSuffix(string(out), "\n") |
| |
| cc[len(cc)-1] = "strip" |
| out, err = exec.Command(cc[0], cc[1:]...).CombinedOutput() |
| if err != nil { |
| Exitf("%s: finding strip failed: %v\n%s", os.Args[0], err, 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 { |
| 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 { |
| Exitf("%s: running strip failed: %v\n%s", os.Args[0], err, out) |
| } |
| // Skip combining if `dsymutil` didn't generate a file. See #11994. |
| if _, err := os.Stat(dsym); os.IsNotExist(err) { |
| return |
| } |
| // For os.Rename to work reliably, must be in same directory as outfile. |
| combinedOutput := *flagOutfile + "~" |
| exef, err := os.Open(*flagOutfile) |
| if err != nil { |
| Exitf("%s: combining dwarf failed: %v", os.Args[0], err) |
| } |
| defer exef.Close() |
| exem, err := macho.NewFile(exef) |
| if err != nil { |
| Exitf("%s: parsing Mach-O header failed: %v", os.Args[0], err) |
| } |
| if err := machoCombineDwarf(ctxt, exef, exem, dsym, combinedOutput); err != nil { |
| Exitf("%s: combining dwarf failed: %v", os.Args[0], err) |
| } |
| os.Remove(*flagOutfile) |
| if err := os.Rename(combinedOutput, *flagOutfile); err != nil { |
| Exitf("%s: %v", os.Args[0], err) |
| } |
| } |
| if ctxt.NeedCodeSign() { |
| err := machoCodeSign(ctxt, *flagOutfile) |
| if err != nil { |
| Exitf("%s: code signing failed: %v", os.Args[0], err) |
| } |
| } |
| } |
| |
| var createTrivialCOnce sync.Once |
| |
| func linkerFlagSupported(arch *sys.Arch, linker, altLinker, flag string) bool { |
| createTrivialCOnce.Do(func() { |
| src := filepath.Join(*flagTmpdir, "trivial.c") |
| if err := ioutil.WriteFile(src, []byte("int main() { return 0; }"), 0666); err != nil { |
| Errorf(nil, "WriteFile trivial.c failed: %v", err) |
| } |
| }) |
| |
| flagsWithNextArgSkip := []string{ |
| "-F", |
| "-l", |
| "-L", |
| "-framework", |
| "-Wl,-framework", |
| "-Wl,-rpath", |
| "-Wl,-undefined", |
| } |
| flagsWithNextArgKeep := []string{ |
| "-arch", |
| "-isysroot", |
| "--sysroot", |
| "-target", |
| } |
| prefixesToKeep := []string{ |
| "-f", |
| "-m", |
| "-p", |
| "-Wl,", |
| "-arch", |
| "-isysroot", |
| "--sysroot", |
| "-target", |
| } |
| |
| flags := hostlinkArchArgs(arch) |
| keep := false |
| skip := false |
| for _, f := range append(flagExtldflags, ldflag...) { |
| if keep { |
| flags = append(flags, f) |
| keep = false |
| } else if skip { |
| skip = false |
| } else if f == "" || f[0] != '-' { |
| } else if contains(flagsWithNextArgSkip, f) { |
| skip = true |
| } else if contains(flagsWithNextArgKeep, f) { |
| flags = append(flags, f) |
| keep = true |
| } else { |
| for _, p := range prefixesToKeep { |
| if strings.HasPrefix(f, p) { |
| flags = append(flags, f) |
| break |
| } |
| } |
| } |
| } |
| |
| 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")) |
| } |
| |
| // hostlinkArchArgs returns arguments to pass to the external linker |
| // based on the architecture. |
| func hostlinkArchArgs(arch *sys.Arch) []string { |
| switch arch.Family { |
| case sys.I386: |
| return []string{"-m32"} |
| case sys.AMD64: |
| if buildcfg.GOOS == "darwin" { |
| return []string{"-arch", "x86_64", "-m64"} |
| } |
| return []string{"-m64"} |
| case sys.S390X: |
| return []string{"-m64"} |
| case sys.ARM: |
| return []string{"-marm"} |
| case sys.ARM64: |
| if buildcfg.GOOS == "darwin" { |
| return []string{"-arch", "arm64"} |
| } |
| case sys.MIPS64: |
| return []string{"-mabi=64"} |
| case sys.MIPS: |
| return []string{"-mabi=32"} |
| case sys.PPC64: |
| if buildcfg.GOOS == "aix" { |
| return []string{"-maix64"} |
| } else { |
| return []string{"-m64"} |
| } |
| |
| } |
| return nil |
| } |
| |
| var wantHdr = objabi.HeaderString() |
| |
| // ldobj loads an input object. If it is a host object (an object |
| // compiled by a non-Go compiler) it returns the Hostobj pointer. If |
| // it is a Go object, it returns nil. |
| func ldobj(ctxt *Link, f *bio.Reader, lib *sym.Library, length int64, pn string, file string) *Hostobj { |
| pkg := objabi.PathToPrefix(lib.Pkg) |
| |
| eof := f.Offset() + length |
| start := f.Offset() |
| c1 := bgetc(f) |
| c2 := bgetc(f) |
| c3 := bgetc(f) |
| c4 := bgetc(f) |
| f.MustSeek(start, 0) |
| |
| unit := &sym.CompilationUnit{Lib: lib} |
| lib.Units = append(lib.Units, unit) |
| |
| magic := uint32(c1)<<24 | uint32(c2)<<16 | uint32(c3)<<8 | uint32(c4) |
| if magic == 0x7f454c46 { // \x7F E L F |
| ldelf := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) { |
| textp, flags, err := loadelf.Load(ctxt.loader, ctxt.Arch, ctxt.IncVersion(), f, pkg, length, pn, ehdr.Flags) |
| if err != nil { |
| Errorf(nil, "%v", err) |
| return |
| } |
| ehdr.Flags = flags |
| ctxt.Textp = append(ctxt.Textp, textp...) |
| } |
| return ldhostobj(ldelf, ctxt.HeadType, f, pkg, length, pn, file) |
| } |
| |
| if magic&^1 == 0xfeedface || magic&^0x01000000 == 0xcefaedfe { |
| ldmacho := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) { |
| textp, err := loadmacho.Load(ctxt.loader, ctxt.Arch, ctxt.IncVersion(), f, pkg, length, pn) |
| if err != nil { |
| Errorf(nil, "%v", err) |
| return |
| } |
| ctxt.Textp = append(ctxt.Textp, textp...) |
| } |
| return ldhostobj(ldmacho, ctxt.HeadType, f, pkg, length, pn, file) |
| } |
| |
| switch c1<<8 | c2 { |
| case 0x4c01, // 386 |
| 0x6486, // amd64 |
| 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) |
| if err != nil { |
| Errorf(nil, "%v", err) |
| return |
| } |
| if len(rsrc) != 0 { |
| setpersrc(ctxt, rsrc) |
| } |
| ctxt.Textp = append(ctxt.Textp, textp...) |
| } |
| return ldhostobj(ldpe, ctxt.HeadType, f, pkg, length, pn, file) |
| } |
| |
| if c1 == 0x01 && (c2 == 0xD7 || c2 == 0xF7) { |
| ldxcoff := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) { |
| textp, err := loadxcoff.Load(ctxt.loader, ctxt.Arch, ctxt.IncVersion(), f, pkg, length, pn) |
| if err != nil { |
| Errorf(nil, "%v", err) |
| return |
| } |
| ctxt.Textp = append(ctxt.Textp, textp...) |
| } |
| return ldhostobj(ldxcoff, ctxt.HeadType, f, pkg, length, pn, file) |
| } |
| |
| if c1 != 'g' || c2 != 'o' || c3 != ' ' || c4 != 'o' { |
| // An unrecognized object is just passed to the external linker. |
| // If we try to read symbols from this object, we will |
| // report an error at that time. |
| unknownObjFormat = true |
| return ldhostobj(nil, ctxt.HeadType, f, pkg, length, pn, file) |
| } |
| |
| /* check the header */ |
| line, err := f.ReadString('\n') |
| if err != nil { |
| Errorf(nil, "truncated object file: %s: %v", pn, err) |
| return nil |
| } |
| |
| if !strings.HasPrefix(line, "go object ") { |
| if strings.HasSuffix(pn, ".go") { |
| Exitf("%s: uncompiled .go source file", pn) |
| return nil |
| } |
| |
| if line == ctxt.Arch.Name { |
| // old header format: just $GOOS |
| Errorf(nil, "%s: stale object file", pn) |
| return nil |
| } |
| |
| Errorf(nil, "%s: not an object file: @%d %q", pn, start, line) |
| return nil |
| } |
| |
| // First, check that the basic GOOS, GOARCH, and Version match. |
| if line != wantHdr { |
| Errorf(nil, "%s: linked object header mismatch:\nhave %q\nwant %q\n", pn, line, wantHdr) |
| } |
| |
| // Skip over exports and other info -- ends with \n!\n. |
| // |
| // Note: It's possible for "\n!\n" to appear within the binary |
| // package export data format. To avoid truncating the package |
| // definition prematurely (issue 21703), we keep track of |
| // how many "$$" delimiters we've seen. |
| |
| import0 := f.Offset() |
| |
| c1 = '\n' // the last line ended in \n |
| c2 = bgetc(f) |
| c3 = bgetc(f) |
| markers := 0 |
| for { |
| if c1 == '\n' { |
| if markers%2 == 0 && c2 == '!' && c3 == '\n' { |
| break |
| } |
| if c2 == '$' && c3 == '$' { |
| markers++ |
| } |
| } |
| |
| c1 = c2 |
| c2 = c3 |
| c3 = bgetc(f) |
| if c3 == -1 { |
| Errorf(nil, "truncated object file: %s", pn) |
| return nil |
| } |
| } |
| |
| import1 := f.Offset() |
| |
| f.MustSeek(import0, 0) |
| ldpkg(ctxt, f, lib, import1-import0-2, pn) // -2 for !\n |
| f.MustSeek(import1, 0) |
| |
| fingerprint := ctxt.loader.Preload(ctxt.IncVersion(), f, lib, unit, eof-f.Offset()) |
| if !fingerprint.IsZero() { // Assembly objects don't have fingerprints. Ignore them. |
| // Check fingerprint, to ensure the importing and imported packages |
| // have consistent view of symbol indices. |
| // Normally the go command should ensure this. But in case something |
| // goes wrong, it could lead to obscure bugs like run-time crash. |
| // Check it here to be sure. |
| if lib.Fingerprint.IsZero() { // Not yet imported. Update its fingerprint. |
| lib.Fingerprint = fingerprint |
| } |
| checkFingerprint(lib, fingerprint, lib.Srcref, lib.Fingerprint) |
| } |
| |
| addImports(ctxt, lib, pn) |
| return nil |
| } |
| |
| func checkFingerprint(lib *sym.Library, libfp goobj.FingerprintType, src string, srcfp goobj.FingerprintType) { |
| if libfp != srcfp { |
| Exitf("fingerprint mismatch: %s has %x, import from %s expecting %x", lib, libfp, src, srcfp) |
| } |
| } |
| |
| func readelfsymboldata(ctxt *Link, f *elf.File, sym *elf.Symbol) []byte { |
| data := make([]byte, sym.Size) |
| sect := f.Sections[sym.Section] |
| if sect.Type != elf.SHT_PROGBITS && sect.Type != elf.SHT_NOTE { |
| Errorf(nil, "reading %s from non-data section", sym.Name) |
| } |
| n, err := sect.ReadAt(data, int64(sym.Value-sect.Addr)) |
| if uint64(n) != sym.Size { |
| Errorf(nil, "reading contents of %s: %v", sym.Name, err) |
| } |
| return data |
| } |
| |
| func readwithpad(r io.Reader, sz int32) ([]byte, error) { |
| data := make([]byte, Rnd(int64(sz), 4)) |
| _, err := io.ReadFull(r, data) |
| if err != nil { |
| return nil, err |
| } |
| data = data[:sz] |
| return data, nil |
| } |
| |
| func readnote(f *elf.File, name []byte, typ int32) ([]byte, error) { |
| for _, sect := range f.Sections { |
| if sect.Type != elf.SHT_NOTE { |
| continue |
| } |
| r := sect.Open() |
| for { |
| var namesize, descsize, noteType int32 |
| err := binary.Read(r, f.ByteOrder, &namesize) |
| if err != nil { |
| if err == io.EOF { |
| break |
| } |
| return nil, fmt.Errorf("read namesize failed: %v", err) |
| } |
| err = binary.Read(r, f.ByteOrder, &descsize) |
| if err != nil { |
| return nil, fmt.Errorf("read descsize failed: %v", err) |
| } |
| err = binary.Read(r, f.ByteOrder, ¬eType) |
| if err != nil { |
| return nil, fmt.Errorf("read type failed: %v", err) |
| } |
| noteName, err := readwithpad(r, namesize) |
| if err != nil { |
| return nil, fmt.Errorf("read name failed: %v", err) |
| } |
| desc, err := readwithpad(r, descsize) |
| if err != nil { |
| return nil, fmt.Errorf("read desc failed: %v", err) |
| } |
| if string(name) == string(noteName) && typ == noteType { |
| return desc, nil |
| } |
| } |
| } |
| return nil, nil |
| } |
| |
| func findshlib(ctxt *Link, shlib string) string { |
| if filepath.IsAbs(shlib) { |
| return shlib |
| } |
| for _, libdir := range ctxt.Libdir { |
| libpath := filepath.Join(libdir, shlib) |
| if _, err := os.Stat(libpath); err == nil { |
| return libpath |
| } |
| } |
| Errorf(nil, "cannot find shared library: %s", shlib) |
| return "" |
| } |
| |
| func ldshlibsyms(ctxt *Link, shlib string) { |
| var libpath string |
| if filepath.IsAbs(shlib) { |
| libpath = shlib |
| shlib = filepath.Base(shlib) |
| } else { |
| libpath = findshlib(ctxt, shlib) |
| if libpath == "" { |
| return |
| } |
| } |
| for _, processedlib := range ctxt.Shlibs { |
| if processedlib.Path == libpath { |
| return |
| } |
| } |
| if ctxt.Debugvlog > 1 { |
| ctxt.Logf("ldshlibsyms: found library with name %s at %s\n", shlib, libpath) |
| } |
| |
| f, err := elf.Open(libpath) |
| if err != nil { |
| Errorf(nil, "cannot open shared library: %s", libpath) |
| return |
| } |
| // Keep the file open as decodetypeGcprog needs to read from it. |
| // TODO: fix. Maybe mmap the file. |
| //defer f.Close() |
| |
| hash, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GOABIHASH_TAG) |
| if err != nil { |
| Errorf(nil, "cannot read ABI hash from shared library %s: %v", libpath, err) |
| return |
| } |
| |
| depsbytes, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GODEPS_TAG) |
| if err != nil { |
| Errorf(nil, "cannot read dep list from shared library %s: %v", libpath, err) |
| return |
| } |
| var deps []string |
| for _, dep := range strings.Split(string(depsbytes), "\n") { |
| if dep == "" { |
| continue |
| } |
| if !filepath.IsAbs(dep) { |
| // If the dep can be interpreted as a path relative to the shlib |
| // in which it was found, do that. Otherwise, we will leave it |
| // to be resolved by libdir lookup. |
| abs := filepath.Join(filepath.Dir(libpath), dep) |
| if _, err := os.Stat(abs); err == nil { |
| dep = abs |
| } |
| } |
| deps = append(deps, dep) |
| } |
| |
| syms, err := f.DynamicSymbols() |
| if err != nil { |
| Errorf(nil, "cannot read symbols from shared library: %s", libpath) |
| return |
| } |
| |
| for _, elfsym := range syms { |
| if elf.ST_TYPE(elfsym.Info) == elf.STT_NOTYPE || elf.ST_TYPE(elfsym.Info) == elf.STT_SECTION { |
| continue |
| } |
| |
| // Symbols whose names start with "type." are compiler |
| // generated, so make functions with that prefix internal. |
| ver := 0 |
| symname := elfsym.Name // (unmangled) symbol name |
| if elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC && strings.HasPrefix(elfsym.Name, "type.") { |
| ver = abiInternalVer |
| } else if buildcfg.Experiment.RegabiWrappers && elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC { |
| // Demangle the ABI name. Keep in sync with symtab.go:mangleABIName. |
| if strings.HasSuffix(elfsym.Name, ".abiinternal") { |
| ver = sym.SymVerABIInternal |
| symname = strings.TrimSuffix(elfsym.Name, ".abiinternal") |
| } else if strings.HasSuffix(elfsym.Name, ".abi0") { |
| ver = 0 |
| symname = strings.TrimSuffix(elfsym.Name, ".abi0") |
| } |
| } |
| |
| l := ctxt.loader |
| s := l.LookupOrCreateSym(symname, ver) |
| |
| // Because loadlib above loads all .a files before loading |
| // any shared libraries, any non-dynimport symbols we find |
| // that duplicate symbols already loaded should be ignored |
| // (the symbols from the .a files "win"). |
| if l.SymType(s) != 0 && l.SymType(s) != sym.SDYNIMPORT { |
| continue |
| } |
| su := l.MakeSymbolUpdater(s) |
| su.SetType(sym.SDYNIMPORT) |
| l.SetSymElfType(s, elf.ST_TYPE(elfsym.Info)) |
| su.SetSize(int64(elfsym.Size)) |
| if elfsym.Section != elf.SHN_UNDEF { |
| // Set .File for the library that actually defines the symbol. |
| l.SetSymPkg(s, libpath) |
| |
| // The decodetype_* functions in decodetype.go need access to |
| // the type data. |
| sname := l.SymName(s) |
| if strings.HasPrefix(sname, "type.") && !strings.HasPrefix(sname, "type..") { |
| su.SetData(readelfsymboldata(ctxt, f, &elfsym)) |
| } |
| } |
| |
| if symname != elfsym.Name { |
| l.SetSymExtname(s, elfsym.Name) |
| } |
| } |
| ctxt.Shlibs = append(ctxt.Shlibs, Shlib{Path: libpath, Hash: hash, Deps: deps, File: f}) |
| } |
| |
| func addsection(ldr *loader.Loader, arch *sys.Arch, seg *sym.Segment, name string, rwx int) *sym.Section { |
| sect := ldr.NewSection() |
| sect.Rwx = uint8(rwx) |
| sect.Name = name |
| sect.Seg = seg |
| sect.Align = int32(arch.PtrSize) // everything is at least pointer-aligned |
| seg.Sections = append(seg.Sections, sect) |
| return sect |
| } |
| |
| type chain struct { |
| sym loader.Sym |
| up *chain |
| limit int // limit on entry to sym |
| } |
| |
| func haslinkregister(ctxt *Link) bool { |
| return ctxt.FixedFrameSize() != 0 |
| } |
| |
| func callsize(ctxt *Link) int { |
| if haslinkregister(ctxt) { |
| return 0 |
| } |
| return ctxt.Arch.RegSize |
| } |
| |
| type stkChk struct { |
| ldr *loader.Loader |
| ctxt *Link |
| morestack loader.Sym |
| done loader.Bitmap |
| } |
| |
| // Walk the call tree and check that there is always enough stack space |
| // for the call frames, especially for a chain of nosplit functions. |
| func (ctxt *Link) dostkcheck() { |
| ldr := ctxt.loader |
| sc := stkChk{ |
| ldr: ldr, |
| ctxt: ctxt, |
| morestack: ldr.Lookup("runtime.morestack", 0), |
| done: loader.MakeBitmap(ldr.NSym()), |
| } |
| |
| // Every splitting function ensures that there are at least StackLimit |
| // bytes available below SP when the splitting prologue finishes. |
| // If the splitting function calls F, then F begins execution with |
| // at least StackLimit - callsize() bytes available. |
| // Check that every function behaves correctly with this amount |
| // of stack, following direct calls in order to piece together chains |
| // of non-splitting functions. |
| var ch chain |
| ch.limit = objabi.StackLimit - callsize(ctxt) |
| if buildcfg.GOARCH == "arm64" { |
| // need extra 8 bytes below SP to save FP |
| ch.limit -= 8 |
| } |
| |
| // Check every function, but do the nosplit functions in a first pass, |
| // to make the printed failure chains as short as possible. |
| for _, s := range ctxt.Textp { |
| if ldr.IsNoSplit(s) { |
| ch.sym = s |
| sc.check(&ch, 0) |
| } |
| } |
| |
| for _, s := range ctxt.Textp { |
| if !ldr.IsNoSplit(s) { |
| ch.sym = s |
| sc.check(&ch, 0) |
| } |
| } |
| } |
| |
| func (sc *stkChk) check(up *chain, depth int) int { |
| limit := up.limit |
| s := up.sym |
| ldr := sc.ldr |
| ctxt := sc.ctxt |
| |
| // Don't duplicate work: only need to consider each |
| // function at top of safe zone once. |
| top := limit == objabi.StackLimit-callsize(ctxt) |
| if top { |
| if sc.done.Has(s) { |
| return 0 |
| } |
| sc.done.Set(s) |
| } |
| |
| if depth > 500 { |
| sc.ctxt.Errorf(s, "nosplit stack check too deep") |
| sc.broke(up, 0) |
| return -1 |
| } |
| |
| if ldr.AttrExternal(s) { |
| // external function. |
| // should never be called directly. |
| // onlyctxt.Diagnose the direct caller. |
| // TODO(mwhudson): actually think about this. |
| // TODO(khr): disabled for now. Calls to external functions can only happen on the g0 stack. |
| // See the trampolines in src/runtime/sys_darwin_$ARCH.go. |
| //if depth == 1 && ldr.SymType(s) != sym.SXREF && !ctxt.DynlinkingGo() && |
| // ctxt.BuildMode != BuildModeCArchive && ctxt.BuildMode != BuildModePIE && ctxt.BuildMode != BuildModeCShared && ctxt.BuildMode != BuildModePlugin { |
| // Errorf(s, "call to external function") |
| //} |
| return -1 |
| } |
| info := ldr.FuncInfo(s) |
| if !info.Valid() { // external function. see above. |
| return -1 |
| } |
| |
| if limit < 0 { |
| sc.broke(up, limit) |
| return -1 |
| } |
| |
| // morestack looks like it calls functions, |
| // but it switches the stack pointer first. |
| if s == sc.morestack { |
| return 0 |
| } |
| |
| var ch chain |
| ch.up = up |
| |
| if !ldr.IsNoSplit(s) { |
| // Ensure we have enough stack to call morestack. |
| ch.limit = limit - callsize(ctxt) |
| ch.sym = sc.morestack |
| if sc.check(&ch, depth+1) < 0 { |
| return -1 |
| } |
| if !top { |
| return 0 |
| } |
| // Raise limit to allow frame. |
| locals := info.Locals() |
| limit = objabi.StackLimit + int(locals) + int(ctxt.FixedFrameSize()) |
| } |
| |
| // Walk through sp adjustments in function, consuming relocs. |
| relocs := ldr.Relocs(s) |
| var ch1 chain |
| pcsp := obj.NewPCIter(uint32(ctxt.Arch.MinLC)) |
| ri := 0 |
| for pcsp.Init(ldr.Data(ldr.Pcsp(s))); !pcsp.Done; pcsp.Next() { |
| // pcsp.value is in effect for [pcsp.pc, pcsp.nextpc). |
| |
| // Check stack size in effect for this span. |
| if int32(limit)-pcsp.Value < 0 { |
| sc.broke(up, int(int32(limit)-pcsp.Value)) |
| return -1 |
| } |
| |
| // Process calls in this span. |
| for ; ri < relocs.Count(); ri++ { |
| r := relocs.At(ri) |
| if uint32(r.Off()) >= pcsp.NextPC { |
| break |
| } |
| t := r.Type() |
| switch { |
| case t.IsDirectCall(): |
| ch.limit = int(int32(limit) - pcsp.Value - int32(callsize(ctxt))) |
| ch.sym = r.Sym() |
| if sc.check(&ch, depth+1) < 0 { |
| return -1 |
| } |
| |
| // Indirect call. Assume it is a call to a splitting function, |
| // so we have to make sure it can call morestack. |
| // Arrange the data structures to report both calls, so that |
| // if there is an error, stkprint shows all the steps involved. |
| case t == objabi.R_CALLIND: |
| ch.limit = int(int32(limit) - pcsp.Value - int32(callsize(ctxt))) |
| ch.sym = 0 |
| ch1.limit = ch.limit - callsize(ctxt) // for morestack in called prologue |
| ch1.up = &ch |
| ch1.sym = sc.morestack |
| if sc.check(&ch1, depth+2) < 0 { |
| return -1 |
| } |
| } |
| } |
| } |
| |
| return 0 |
| } |
| |
| func (sc *stkChk) broke(ch *chain, limit int) { |
| sc.ctxt.Errorf(ch.sym, "nosplit stack overflow") |
| sc.print(ch, limit) |
| } |
| |
| func (sc *stkChk) print(ch *chain, limit int) { |
| ldr := sc.ldr |
| ctxt := sc.ctxt |
| var name string |
| if ch.sym != 0 { |
| name = fmt.Sprintf("%s<%d>", ldr.SymName(ch.sym), ldr.SymVersion(ch.sym)) |
| if ldr.IsNoSplit(ch.sym) { |
| name += " (nosplit)" |
| } |
| } else { |
| name = "function pointer" |
| } |
| |
| if ch.up == nil { |
| // top of chain. ch.sym != 0. |
| if ldr.IsNoSplit(ch.sym) { |
| fmt.Printf("\t%d\tassumed on entry to %s\n", ch.limit, name) |
| } else { |
| fmt.Printf("\t%d\tguaranteed after split check in %s\n", ch.limit, name) |
| } |
| } else { |
| sc.print(ch.up, ch.limit+callsize(ctxt)) |
| if !haslinkregister(ctxt) { |
| fmt.Printf("\t%d\ton entry to %s\n", ch.limit, name) |
| } |
| } |
| |
| if ch.limit != limit { |
| fmt.Printf("\t%d\tafter %s uses %d\n", limit, name, ch.limit-limit) |
| } |
| } |
| |
| func usage() { |
| fmt.Fprintf(os.Stderr, "usage: link [options] main.o\n") |
| objabi.Flagprint(os.Stderr) |
| Exit(2) |
| } |
| |
| type SymbolType int8 // TODO: after genasmsym is gone, maybe rename to plan9typeChar or something |
| |
| const ( |
| // see also https://9p.io/magic/man2html/1/nm |
| TextSym SymbolType = 'T' |
| DataSym SymbolType = 'D' |
| BSSSym SymbolType = 'B' |
| UndefinedSym SymbolType = 'U' |
| TLSSym SymbolType = 't' |
| FrameSym SymbolType = 'm' |
| ParamSym SymbolType = 'p' |
| AutoSym SymbolType = 'a' |
| |
| // Deleted auto (not a real sym, just placeholder for type) |
| DeletedAutoSym = 'x' |
| ) |
| |
| // defineInternal defines a symbol used internally by the go runtime. |
| func (ctxt *Link) defineInternal(p string, t sym.SymKind) loader.Sym { |
| s := ctxt.loader.CreateSymForUpdate(p, 0) |
| s.SetType(t) |
| s.SetSpecial(true) |
| s.SetLocal(true) |
| return s.Sym() |
| } |
| |
| func (ctxt *Link) xdefine(p string, t sym.SymKind, v int64) loader.Sym { |
| s := ctxt.defineInternal(p, t) |
| ctxt.loader.SetSymValue(s, v) |
| return s |
| } |
| |
| func datoff(ldr *loader.Loader, s loader.Sym, addr int64) int64 { |
| if uint64(addr) >= Segdata.Vaddr { |
| return int64(uint64(addr) - Segdata.Vaddr + Segdata.Fileoff) |
| } |
| if uint64(addr) >= Segtext.Vaddr { |
| return int64(uint64(addr) - Segtext.Vaddr + Segtext.Fileoff) |
| } |
| ldr.Errorf(s, "invalid datoff %#x", addr) |
| return 0 |
| } |
| |
| func Entryvalue(ctxt *Link) int64 { |
| a := *flagEntrySymbol |
| if a[0] >= '0' && a[0] <= '9' { |
| return atolwhex(a) |
| } |
| ldr := ctxt.loader |
| s := ldr.Lookup(a, 0) |
| st := ldr.SymType(s) |
| if st == 0 { |
| return *FlagTextAddr |
| } |
| if !ctxt.IsAIX() && st != sym.STEXT { |
| ldr.Errorf(s, "entry not text") |
| } |
| return ldr.SymValue(s) |
| } |
| |
| func (ctxt *Link) callgraph() { |
| if !*FlagC { |
| return |
| } |
| |
| ldr := ctxt.loader |
| for _, s := range ctxt.Textp { |
| relocs := ldr.Relocs(s) |
| for i := 0; i < relocs.Count(); i++ { |
| r := relocs.At(i) |
| rs := r.Sym() |
| if rs == 0 { |
| continue |
| } |
| if r.Type().IsDirectCall() && ldr.SymType(rs) == sym.STEXT { |
| ctxt.Logf("%s calls %s\n", ldr.SymName(s), ldr.SymName(rs)) |
| } |
| } |
| } |
| } |
| |
| func Rnd(v int64, r int64) int64 { |
| if r <= 0 { |
| return v |
| } |
| v += r - 1 |
| c := v % r |
| if c < 0 { |
| c += r |
| } |
| v -= c |
| return v |
| } |
| |
| func bgetc(r *bio.Reader) int { |
| c, err := r.ReadByte() |
| if err != nil { |
| if err != io.EOF { |
| log.Fatalf("reading input: %v", err) |
| } |
| return -1 |
| } |
| return int(c) |
| } |
| |
| type markKind uint8 // for postorder traversal |
| const ( |
| _ markKind = iota |
| visiting |
| visited |
| ) |
| |
| func postorder(libs []*sym.Library) []*sym.Library { |
| order := make([]*sym.Library, 0, len(libs)) // hold the result |
| mark := make(map[*sym.Library]markKind, len(libs)) |
| for _, lib := range libs { |
| dfs(lib, mark, &order) |
| } |
| return order |
| } |
| |
| func dfs(lib *sym.Library, mark map[*sym.Library]markKind, order *[]*sym.Library) { |
| if mark[lib] == visited { |
| return |
| } |
| if mark[lib] == visiting { |
| panic("found import cycle while visiting " + lib.Pkg) |
| } |
| mark[lib] = visiting |
| for _, i := range lib.Imports { |
| dfs(i, mark, order) |
| } |
| mark[lib] = visited |
| *order = append(*order, lib) |
| } |
| |
| func ElfSymForReloc(ctxt *Link, s loader.Sym) int32 { |
| // If putelfsym created a local version of this symbol, use that in all |
| // relocations. |
| les := ctxt.loader.SymLocalElfSym(s) |
| if les != 0 { |
| return les |
| } else { |
| return ctxt.loader.SymElfSym(s) |
| } |
| } |
| |
| func AddGotSym(target *Target, ldr *loader.Loader, syms *ArchSyms, s loader.Sym, elfRelocTyp uint32) { |
| if ldr.SymGot(s) >= 0 { |
| return |
| } |
| |
| Adddynsym(ldr, target, syms, s) |
| got := ldr.MakeSymbolUpdater(syms.GOT) |
| ldr.SetGot(s, int32(got.Size())) |
| got.AddUint(target.Arch, 0) |
| |
| if target.IsElf() { |
| if target.Arch.PtrSize == 8 { |
| rela := ldr.MakeSymbolUpdater(syms.Rela) |
| rela.AddAddrPlus(target.Arch, got.Sym(), int64(ldr.SymGot(s))) |
| rela.AddUint64(target.Arch, elf.R_INFO(uint32(ldr.SymDynid(s)), elfRelocTyp)) |
| rela.AddUint64(target.Arch, 0) |
| } else { |
| rel := ldr.MakeSymbolUpdater(syms.Rel) |
| rel.AddAddrPlus(target.Arch, got.Sym(), int64(ldr.SymGot(s))) |
| rel.AddUint32(target.Arch, elf.R_INFO32(uint32(ldr.SymDynid(s)), elfRelocTyp)) |
| } |
| } else if target.IsDarwin() { |
| leg := ldr.MakeSymbolUpdater(syms.LinkEditGOT) |
| leg.AddUint32(target.Arch, uint32(ldr.SymDynid(s))) |
| if target.IsPIE() && target.IsInternal() { |
| // Mach-O relocations are a royal pain to lay out. |
| // They use a compact stateful bytecode representation. |
| // Here we record what are needed and encode them later. |
| MachoAddBind(int64(ldr.SymGot(s)), s) |
| } |
| } else { |
| ldr.Errorf(s, "addgotsym: unsupported binary format") |
| } |
| } |
