package ld import ( "bytes" "cmd/internal/obj" "encoding/binary" "fmt" "log" "sort" "strings" ) /* Derived from Plan 9 from User Space's src/libmach/elf.h, elf.c http://code.swtch.com/plan9port/src/tip/src/libmach/ Copyright © 2004 Russ Cox. Portions Copyright © 2008-2010 Google Inc. Portions Copyright © 2010 The Go Authors. 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. */ const ( ElfClassNone = 0 ElfClass32 = 1 ElfClass64 = 2 ) const ( ElfDataNone = 0 ElfDataLsb = 1 ElfDataMsb = 2 ) const ( ElfTypeNone = 0 ElfTypeRelocatable = 1 ElfTypeExecutable = 2 ElfTypeSharedObject = 3 ElfTypeCore = 4 ) const ( ElfMachNone = 0 ElfMach32100 = 1 ElfMachSparc = 2 ElfMach386 = 3 ElfMach68000 = 4 ElfMach88000 = 5 ElfMach486 = 6 ElfMach860 = 7 ElfMachMips = 8 ElfMachS370 = 9 ElfMachMipsLe = 10 ElfMachParisc = 15 ElfMachVpp500 = 17 ElfMachSparc32Plus = 18 ElfMach960 = 19 ElfMachPower = 20 ElfMachPower64 = 21 ElfMachS390 = 22 ElfMachV800 = 36 ElfMachFr20 = 37 ElfMachRh32 = 38 ElfMachRce = 39 ElfMachArm = 40 ElfMachAlpha = 41 ElfMachSH = 42 ElfMachSparc9 = 43 ElfMachAmd64 = 62 ElfMachArm64 = 183 ) const ( ElfAbiNone = 0 ElfAbiSystemV = 0 ElfAbiHPUX = 1 ElfAbiNetBSD = 2 ElfAbiLinux = 3 ElfAbiSolaris = 6 ElfAbiAix = 7 ElfAbiIrix = 8 ElfAbiFreeBSD = 9 ElfAbiTru64 = 10 ElfAbiModesto = 11 ElfAbiOpenBSD = 12 ElfAbiARM = 97 ElfAbiEmbedded = 255 ) const ( ElfSectNone = 0 ElfSectProgbits = 1 ElfSectSymtab = 2 ElfSectStrtab = 3 ElfSectRela = 4 ElfSectHash = 5 ElfSectDynamic = 6 ElfSectNote = 7 ElfSectNobits = 8 ElfSectRel = 9 ElfSectShlib = 10 ElfSectDynsym = 11 ElfSectFlagWrite = 0x1 ElfSectFlagAlloc = 0x2 ElfSectFlagExec = 0x4 ) const ( ElfSymBindLocal = 0 ElfSymBindGlobal = 1 ElfSymBindWeak = 2 ) const ( ElfSymTypeNone = 0 ElfSymTypeObject = 1 ElfSymTypeFunc = 2 ElfSymTypeSection = 3 ElfSymTypeFile = 4 ) const ( ElfSymShnNone = 0 ElfSymShnAbs = 0xFFF1 ElfSymShnCommon = 0xFFF2 ) const ( ElfProgNone = 0 ElfProgLoad = 1 ElfProgDynamic = 2 ElfProgInterp = 3 ElfProgNote = 4 ElfProgShlib = 5 ElfProgPhdr = 6 ElfProgFlagExec = 0x1 ElfProgFlagWrite = 0x2 ElfProgFlagRead = 0x4 ) const ( ElfNotePrStatus = 1 ElfNotePrFpreg = 2 ElfNotePrPsinfo = 3 ElfNotePrTaskstruct = 4 ElfNotePrAuxv = 6 ElfNotePrXfpreg = 0x46e62b7f ) type ElfHdrBytes struct { Ident [16]uint8 Type [2]uint8 Machine [2]uint8 Version [4]uint8 Entry [4]uint8 Phoff [4]uint8 Shoff [4]uint8 Flags [4]uint8 Ehsize [2]uint8 Phentsize [2]uint8 Phnum [2]uint8 Shentsize [2]uint8 Shnum [2]uint8 Shstrndx [2]uint8 } type ElfSectBytes struct { Name [4]uint8 Type [4]uint8 Flags [4]uint8 Addr [4]uint8 Off [4]uint8 Size [4]uint8 Link [4]uint8 Info [4]uint8 Align [4]uint8 Entsize [4]uint8 } type ElfProgBytes struct { } type ElfSymBytes struct { Name [4]uint8 Value [4]uint8 Size [4]uint8 Info uint8 Other uint8 Shndx [2]uint8 } type ElfHdrBytes64 struct { Ident [16]uint8 Type [2]uint8 Machine [2]uint8 Version [4]uint8 Entry [8]uint8 Phoff [8]uint8 Shoff [8]uint8 Flags [4]uint8 Ehsize [2]uint8 Phentsize [2]uint8 Phnum [2]uint8 Shentsize [2]uint8 Shnum [2]uint8 Shstrndx [2]uint8 } type ElfSectBytes64 struct { Name [4]uint8 Type [4]uint8 Flags [8]uint8 Addr [8]uint8 Off [8]uint8 Size [8]uint8 Link [4]uint8 Info [4]uint8 Align [8]uint8 Entsize [8]uint8 } type ElfProgBytes64 struct { } type ElfSymBytes64 struct { Name [4]uint8 Info uint8 Other uint8 Shndx [2]uint8 Value [8]uint8 Size [8]uint8 } type ElfSect struct { name string nameoff uint32 type_ uint32 flags uint64 addr uint64 off uint64 size uint64 link uint32 info uint32 align uint64 entsize uint64 base []byte sym *LSym } type ElfObj struct { f *obj.Biobuf base int64 // offset in f where ELF begins length int64 // length of ELF is64 int name string e binary.ByteOrder sect []ElfSect nsect uint shstrtab string nsymtab int symtab *ElfSect symstr *ElfSect type_ uint32 machine uint32 version uint32 entry uint64 phoff uint64 shoff uint64 flags uint32 ehsize uint32 phentsize uint32 phnum uint32 shentsize uint32 shnum uint32 shstrndx uint32 } type ElfSym struct { name string value uint64 size uint64 bind uint8 type_ uint8 other uint8 shndx uint16 sym *LSym } var ElfMagic = [4]uint8{0x7F, 'E', 'L', 'F'} func valuecmp(a *LSym, b *LSym) int { if a.Value < b.Value { return -1 } if a.Value > b.Value { return +1 } return 0 } func ldelf(f *obj.Biobuf, pkg string, length int64, pn string) { if Debug['v'] != 0 { fmt.Fprintf(&Bso, "%5.2f ldelf %s\n", obj.Cputime(), pn) } Ctxt.Version++ base := int32(obj.Boffset(f)) var add uint64 var e binary.ByteOrder var elfobj *ElfObj var err error var flag int var hdr *ElfHdrBytes var hdrbuf [64]uint8 var info uint64 var is64 int var j int var n int var name string var p []byte var r []Reloc var rela int var rp *Reloc var rsect *ElfSect var s *LSym var sect *ElfSect var sym ElfSym var symbols []*LSym if obj.Bread(f, hdrbuf[:]) != len(hdrbuf) { goto bad } hdr = new(ElfHdrBytes) binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter if string(hdr.Ident[:4]) != "\x7FELF" { goto bad } switch hdr.Ident[5] { case ElfDataLsb: e = binary.LittleEndian case ElfDataMsb: e = binary.BigEndian default: goto bad } // read header elfobj = new(ElfObj) elfobj.e = e elfobj.f = f elfobj.base = int64(base) elfobj.length = length elfobj.name = pn is64 = 0 if hdr.Ident[4] == ElfClass64 { is64 = 1 hdr := new(ElfHdrBytes64) binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter elfobj.type_ = uint32(e.Uint16(hdr.Type[:])) elfobj.machine = uint32(e.Uint16(hdr.Machine[:])) elfobj.version = e.Uint32(hdr.Version[:]) elfobj.phoff = e.Uint64(hdr.Phoff[:]) elfobj.shoff = e.Uint64(hdr.Shoff[:]) elfobj.flags = e.Uint32(hdr.Flags[:]) elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:])) elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:])) elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:])) elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:])) elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:])) elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:])) } else { elfobj.type_ = uint32(e.Uint16(hdr.Type[:])) elfobj.machine = uint32(e.Uint16(hdr.Machine[:])) elfobj.version = e.Uint32(hdr.Version[:]) elfobj.entry = uint64(e.Uint32(hdr.Entry[:])) elfobj.phoff = uint64(e.Uint32(hdr.Phoff[:])) elfobj.shoff = uint64(e.Uint32(hdr.Shoff[:])) elfobj.flags = e.Uint32(hdr.Flags[:]) elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:])) elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:])) elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:])) elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:])) elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:])) elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:])) } elfobj.is64 = is64 if uint32(hdr.Ident[6]) != elfobj.version { goto bad } if e.Uint16(hdr.Type[:]) != ElfTypeRelocatable { Diag("%s: elf but not elf relocatable object", pn) return } switch Thearch.Thechar { default: Diag("%s: elf %s unimplemented", pn, Thestring) return case '5': if e != binary.LittleEndian || elfobj.machine != ElfMachArm || hdr.Ident[4] != ElfClass32 { Diag("%s: elf object but not arm", pn) return } case '6': if e != binary.LittleEndian || elfobj.machine != ElfMachAmd64 || hdr.Ident[4] != ElfClass64 { Diag("%s: elf object but not amd64", pn) return } case '7': if e != binary.LittleEndian || elfobj.machine != ElfMachArm64 || hdr.Ident[4] != ElfClass64 { Diag("%s: elf object but not arm64", pn) return } case '8': if e != binary.LittleEndian || elfobj.machine != ElfMach386 || hdr.Ident[4] != ElfClass32 { Diag("%s: elf object but not 386", pn) return } case '9': if elfobj.machine != ElfMachPower64 || hdr.Ident[4] != ElfClass64 { Diag("%s: elf object but not ppc64", pn) return } } // load section list into memory. elfobj.sect = make([]ElfSect, elfobj.shnum) elfobj.nsect = uint(elfobj.shnum) for i := 0; uint(i) < elfobj.nsect; i++ { if obj.Bseek(f, int64(uint64(base)+elfobj.shoff+uint64(int64(i)*int64(elfobj.shentsize))), 0) < 0 { goto bad } sect = &elfobj.sect[i] if is64 != 0 { var b ElfSectBytes64 if err = binary.Read(f, e, &b); err != nil { goto bad } sect.nameoff = uint32(e.Uint32(b.Name[:])) sect.type_ = e.Uint32(b.Type[:]) sect.flags = e.Uint64(b.Flags[:]) sect.addr = e.Uint64(b.Addr[:]) sect.off = e.Uint64(b.Off[:]) sect.size = e.Uint64(b.Size[:]) sect.link = e.Uint32(b.Link[:]) sect.info = e.Uint32(b.Info[:]) sect.align = e.Uint64(b.Align[:]) sect.entsize = e.Uint64(b.Entsize[:]) } else { var b ElfSectBytes if err = binary.Read(f, e, &b); err != nil { goto bad } sect.nameoff = uint32(e.Uint32(b.Name[:])) sect.type_ = e.Uint32(b.Type[:]) sect.flags = uint64(e.Uint32(b.Flags[:])) sect.addr = uint64(e.Uint32(b.Addr[:])) sect.off = uint64(e.Uint32(b.Off[:])) sect.size = uint64(e.Uint32(b.Size[:])) sect.link = e.Uint32(b.Link[:]) sect.info = e.Uint32(b.Info[:]) sect.align = uint64(e.Uint32(b.Align[:])) sect.entsize = uint64(e.Uint32(b.Entsize[:])) } } // read section string table and translate names if elfobj.shstrndx >= uint32(elfobj.nsect) { err = fmt.Errorf("shstrndx out of range %d >= %d", elfobj.shstrndx, elfobj.nsect) goto bad } sect = &elfobj.sect[elfobj.shstrndx] if err = elfmap(elfobj, sect); err != nil { goto bad } for i := 0; uint(i) < elfobj.nsect; i++ { if elfobj.sect[i].nameoff != 0 { elfobj.sect[i].name = cstring(sect.base[elfobj.sect[i].nameoff:]) } } // load string table for symbols into memory. elfobj.symtab = section(elfobj, ".symtab") if elfobj.symtab == nil { // our work is done here - no symbols means nothing can refer to this file return } if elfobj.symtab.link <= 0 || elfobj.symtab.link >= uint32(elfobj.nsect) { Diag("%s: elf object has symbol table with invalid string table link", pn) return } elfobj.symstr = &elfobj.sect[elfobj.symtab.link] if is64 != 0 { elfobj.nsymtab = int(elfobj.symtab.size / ELF64SYMSIZE) } else { elfobj.nsymtab = int(elfobj.symtab.size / ELF32SYMSIZE) } if err = elfmap(elfobj, elfobj.symtab); err != nil { goto bad } if err = elfmap(elfobj, elfobj.symstr); err != nil { goto bad } // load text and data segments into memory. // they are not as small as the section lists, but we'll need // the memory anyway for the symbol images, so we might // as well use one large chunk. // create symbols for elfmapped sections for i := 0; uint(i) < elfobj.nsect; i++ { sect = &elfobj.sect[i] if (sect.type_ != ElfSectProgbits && sect.type_ != ElfSectNobits) || sect.flags&ElfSectFlagAlloc == 0 { continue } if sect.type_ != ElfSectNobits { if err = elfmap(elfobj, sect); err != nil { goto bad } } name = fmt.Sprintf("%s(%s)", pkg, sect.name) s = Linklookup(Ctxt, name, Ctxt.Version) switch int(sect.flags) & (ElfSectFlagAlloc | ElfSectFlagWrite | ElfSectFlagExec) { default: err = fmt.Errorf("unexpected flags for ELF section %s", sect.name) goto bad case ElfSectFlagAlloc: s.Type = obj.SRODATA case ElfSectFlagAlloc + ElfSectFlagWrite: if sect.type_ == ElfSectNobits { s.Type = obj.SNOPTRBSS } else { s.Type = obj.SNOPTRDATA } case ElfSectFlagAlloc + ElfSectFlagExec: s.Type = obj.STEXT } if sect.name == ".got" || sect.name == ".toc" { s.Type = obj.SELFGOT } if sect.type_ == ElfSectProgbits { s.P = sect.base s.P = s.P[:sect.size] } s.Size = int64(sect.size) s.Align = int32(sect.align) sect.sym = s } // enter sub-symbols into symbol table. // symbol 0 is the null symbol. symbols = make([]*LSym, elfobj.nsymtab) for i := 1; i < elfobj.nsymtab; i++ { if err = readelfsym(elfobj, i, &sym, 1); err != nil { goto bad } symbols[i] = sym.sym if sym.type_ != ElfSymTypeFunc && sym.type_ != ElfSymTypeObject && sym.type_ != ElfSymTypeNone { continue } if sym.shndx == ElfSymShnCommon { s = sym.sym if uint64(s.Size) < sym.size { s.Size = int64(sym.size) } if s.Type == 0 || s.Type == obj.SXREF { s.Type = obj.SNOPTRBSS } continue } if uint(sym.shndx) >= elfobj.nsect || sym.shndx == 0 { continue } // even when we pass needSym == 1 to readelfsym, it might still return nil to skip some unwanted symbols if sym.sym == nil { continue } sect = &elfobj.sect[sym.shndx:][0] if sect.sym == nil { if strings.HasPrefix(sym.name, ".Linfo_string") { // clang does this continue } Diag("%s: sym#%d: ignoring %s in section %d (type %d)", pn, i, sym.name, sym.shndx, sym.type_) continue } s = sym.sym if s.Outer != nil { if s.Dupok != 0 { continue } Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name) } s.Sub = sect.sym.Sub sect.sym.Sub = s s.Type = sect.sym.Type | s.Type&^obj.SMASK | obj.SSUB if s.Cgoexport&CgoExportDynamic == 0 { s.Dynimplib = "" // satisfy dynimport } s.Value = int64(sym.value) s.Size = int64(sym.size) s.Outer = sect.sym if sect.sym.Type == obj.STEXT { if s.External != 0 && s.Dupok == 0 { Diag("%s: duplicate definition of %s", pn, s.Name) } s.External = 1 } if elfobj.machine == ElfMachPower64 { flag = int(sym.other) >> 5 if 2 <= flag && flag <= 6 { s.Localentry = 1 << uint(flag-2) } else if flag == 7 { Diag("%s: invalid sym.other 0x%x for %s", pn, sym.other, s.Name) } } } // Sort outer lists by address, adding to textp. // This keeps textp in increasing address order. for i := 0; uint(i) < elfobj.nsect; i++ { s = elfobj.sect[i].sym if s == nil { continue } if s.Sub != nil { s.Sub = listsort(s.Sub, valuecmp, listsubp) } if s.Type == obj.STEXT { if s.Onlist != 0 { log.Fatalf("symbol %s listed multiple times", s.Name) } s.Onlist = 1 if Ctxt.Etextp != nil { Ctxt.Etextp.Next = s } else { Ctxt.Textp = s } Ctxt.Etextp = s for s = s.Sub; s != nil; s = s.Sub { if s.Onlist != 0 { log.Fatalf("symbol %s listed multiple times", s.Name) } s.Onlist = 1 Ctxt.Etextp.Next = s Ctxt.Etextp = s } } } // load relocations for i := 0; uint(i) < elfobj.nsect; i++ { rsect = &elfobj.sect[i] if rsect.type_ != ElfSectRela && rsect.type_ != ElfSectRel { continue } if rsect.info >= uint32(elfobj.nsect) || elfobj.sect[rsect.info].base == nil { continue } sect = &elfobj.sect[rsect.info] if err = elfmap(elfobj, rsect); err != nil { goto bad } rela = 0 if rsect.type_ == ElfSectRela { rela = 1 } n = int(rsect.size / uint64(4+4*is64) / uint64(2+rela)) r = make([]Reloc, n) p = rsect.base for j = 0; j < n; j++ { add = 0 rp = &r[j] if is64 != 0 { // 64-bit rel/rela rp.Off = int32(e.Uint64(p)) p = p[8:] info = e.Uint64(p) p = p[8:] if rela != 0 { add = e.Uint64(p) p = p[8:] } } else { // 32-bit rel/rela rp.Off = int32(e.Uint32(p)) p = p[4:] info = uint64(e.Uint32(p)) info = info>>8<<32 | info&0xff // convert to 64-bit info p = p[4:] if rela != 0 { add = uint64(e.Uint32(p)) p = p[4:] } } if info&0xffffffff == 0 { // skip R_*_NONE relocation j-- n-- continue } if info>>32 == 0 { // absolute relocation, don't bother reading the null symbol rp.Sym = nil } else { if err = readelfsym(elfobj, int(info>>32), &sym, 0); err != nil { goto bad } sym.sym = symbols[info>>32] if sym.sym == nil { err = fmt.Errorf("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", sect.sym.Name, j, int(info>>32), sym.name, sym.shndx, sym.type_) goto bad } rp.Sym = sym.sym } rp.Type = int32(reltype(pn, int(uint32(info)), &rp.Siz)) if rela != 0 { rp.Add = int64(add) } else { // load addend from image if rp.Siz == 4 { rp.Add = int64(e.Uint32(sect.base[rp.Off:])) } else if rp.Siz == 8 { rp.Add = int64(e.Uint64(sect.base[rp.Off:])) } else { Diag("invalid rela size %d", rp.Siz) } } if rp.Siz == 2 { rp.Add = int64(int16(rp.Add)) } if rp.Siz == 4 { rp.Add = int64(int32(rp.Add)) } } //print("rel %s %d %d %s %#llx\n", sect->sym->name, rp->type, rp->siz, rp->sym->name, rp->add); sort.Sort(rbyoff(r[:n])) // just in case s = sect.sym s.R = r s.R = s.R[:n] } return bad: Diag("%s: malformed elf file: %v", pn, err) } func section(elfobj *ElfObj, name string) *ElfSect { for i := 0; uint(i) < elfobj.nsect; i++ { if elfobj.sect[i].name != "" && name != "" && elfobj.sect[i].name == name { return &elfobj.sect[i] } } return nil } func elfmap(elfobj *ElfObj, sect *ElfSect) (err error) { if sect.base != nil { return nil } if sect.off+sect.size > uint64(elfobj.length) { err = fmt.Errorf("elf section past end of file") return err } sect.base = make([]byte, sect.size) err = fmt.Errorf("short read") if obj.Bseek(elfobj.f, int64(uint64(elfobj.base)+sect.off), 0) < 0 || obj.Bread(elfobj.f, sect.base) != len(sect.base) { return err } return nil } func readelfsym(elfobj *ElfObj, i int, sym *ElfSym, needSym int) (err error) { if i >= elfobj.nsymtab || i < 0 { err = fmt.Errorf("invalid elf symbol index") return err } if i == 0 { Diag("readym: read null symbol!") } if elfobj.is64 != 0 { b := new(ElfSymBytes64) binary.Read(bytes.NewReader(elfobj.symtab.base[i*ELF64SYMSIZE:(i+1)*ELF64SYMSIZE]), elfobj.e, b) sym.name = cstring(elfobj.symstr.base[elfobj.e.Uint32(b.Name[:]):]) sym.value = elfobj.e.Uint64(b.Value[:]) sym.size = elfobj.e.Uint64(b.Size[:]) sym.shndx = elfobj.e.Uint16(b.Shndx[:]) sym.bind = b.Info >> 4 sym.type_ = b.Info & 0xf sym.other = b.Other } else { b := new(ElfSymBytes) binary.Read(bytes.NewReader(elfobj.symtab.base[i*ELF32SYMSIZE:(i+1)*ELF32SYMSIZE]), elfobj.e, b) sym.name = cstring(elfobj.symstr.base[elfobj.e.Uint32(b.Name[:]):]) sym.value = uint64(elfobj.e.Uint32(b.Value[:])) sym.size = uint64(elfobj.e.Uint32(b.Size[:])) sym.shndx = elfobj.e.Uint16(b.Shndx[:]) sym.bind = b.Info >> 4 sym.type_ = b.Info & 0xf sym.other = b.Other } var s *LSym if sym.name == "_GLOBAL_OFFSET_TABLE_" { sym.name = ".got" } if sym.name == ".TOC." { // Magic symbol on ppc64. Will be set to this object // file's .got+0x8000. sym.bind = ElfSymBindLocal } switch sym.type_ { case ElfSymTypeSection: s = elfobj.sect[sym.shndx].sym case ElfSymTypeObject, ElfSymTypeFunc, ElfSymTypeNone: switch sym.bind { case ElfSymBindGlobal: if needSym != 0 { s = Linklookup(Ctxt, sym.name, 0) // for global scoped hidden symbols we should insert it into // symbol hash table, but mark them as hidden. // __i686.get_pc_thunk.bx is allowed to be duplicated, to // workaround that we set dupok. // TODO(minux): correctly handle __i686.get_pc_thunk.bx without // set dupok generally. See http://codereview.appspot.com/5823055/ // comment #5 for details. if s != nil && sym.other == 2 { s.Type |= obj.SHIDDEN s.Dupok = 1 } } case ElfSymBindLocal: if Thearch.Thechar == '5' && (strings.HasPrefix(sym.name, "$a") || strings.HasPrefix(sym.name, "$d")) { // binutils for arm generate these mapping // symbols, ignore these break } if sym.name == ".TOC." { // We need to be able to look this up, // so put it in the hash table. if needSym != 0 { s = Linklookup(Ctxt, sym.name, Ctxt.Version) s.Type |= obj.SHIDDEN } break } if needSym != 0 { // local names and hidden visiblity global names are unique // and should only reference by its index, not name, so we // don't bother to add them into hash table s = linknewsym(Ctxt, sym.name, Ctxt.Version) s.Type |= obj.SHIDDEN } case ElfSymBindWeak: if needSym != 0 { s = linknewsym(Ctxt, sym.name, 0) if sym.other == 2 { s.Type |= obj.SHIDDEN } } default: err = fmt.Errorf("%s: invalid symbol binding %d", sym.name, sym.bind) return err } } if s != nil && s.Type == 0 && sym.type_ != ElfSymTypeSection { s.Type = obj.SXREF } sym.sym = s return nil } type rbyoff []Reloc func (x rbyoff) Len() int { return len(x) } func (x rbyoff) Swap(i, j int) { x[i], x[j] = x[j], x[i] } func (x rbyoff) Less(i, j int) bool { a := &x[i] b := &x[j] if a.Off < b.Off { return true } if a.Off > b.Off { return false } return false } func reltype(pn string, elftype int, siz *uint8) int { switch uint32(Thearch.Thechar) | uint32(elftype)<<24 { default: Diag("%s: unknown relocation type %d; compiled without -fpic?", pn, elftype) fallthrough case '9' | R_PPC64_TOC16<<24, '9' | R_PPC64_TOC16_LO<<24, '9' | R_PPC64_TOC16_HI<<24, '9' | R_PPC64_TOC16_HA<<24, '9' | R_PPC64_TOC16_DS<<24, '9' | R_PPC64_TOC16_LO_DS<<24, '9' | R_PPC64_REL16_LO<<24, '9' | R_PPC64_REL16_HI<<24, '9' | R_PPC64_REL16_HA<<24: *siz = 2 case '5' | R_ARM_ABS32<<24, '5' | R_ARM_GOT32<<24, '5' | R_ARM_PLT32<<24, '5' | R_ARM_GOTOFF<<24, '5' | R_ARM_GOTPC<<24, '5' | R_ARM_THM_PC22<<24, '5' | R_ARM_REL32<<24, '5' | R_ARM_CALL<<24, '5' | R_ARM_V4BX<<24, '5' | R_ARM_GOT_PREL<<24, '5' | R_ARM_PC24<<24, '5' | R_ARM_JUMP24<<24, '6' | R_X86_64_PC32<<24, '6' | R_X86_64_PLT32<<24, '6' | R_X86_64_GOTPCREL<<24, '8' | R_386_32<<24, '8' | R_386_PC32<<24, '8' | R_386_GOT32<<24, '8' | R_386_PLT32<<24, '8' | R_386_GOTOFF<<24, '8' | R_386_GOTPC<<24, '9' | R_PPC64_REL24<<24: *siz = 4 case '6' | R_X86_64_64<<24, '9' | R_PPC64_ADDR64<<24: *siz = 8 } return 256 + elftype }