| // Derived from Inferno utils/6l/obj.c and utils/6l/span.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/obj.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/span.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 obj |
| |
| import ( |
| "cmd/internal/goobj" |
| "cmd/internal/objabi" |
| "crypto/md5" |
| "fmt" |
| "internal/buildcfg" |
| "log" |
| "math" |
| "sort" |
| ) |
| |
| func Linknew(arch *LinkArch) *Link { |
| ctxt := new(Link) |
| ctxt.hash = make(map[string]*LSym) |
| ctxt.funchash = make(map[string]*LSym) |
| ctxt.statichash = make(map[string]*LSym) |
| ctxt.Arch = arch |
| ctxt.Pathname = objabi.WorkingDir() |
| |
| if err := ctxt.Headtype.Set(buildcfg.GOOS); err != nil { |
| log.Fatalf("unknown goos %s", buildcfg.GOOS) |
| } |
| |
| ctxt.Flag_optimize = true |
| return ctxt |
| } |
| |
| // LookupDerived looks up or creates the symbol with name derived from symbol s. |
| // The resulting symbol will be static iff s is. |
| func (ctxt *Link) LookupDerived(s *LSym, name string) *LSym { |
| if s.Static() { |
| return ctxt.LookupStatic(name) |
| } |
| return ctxt.Lookup(name) |
| } |
| |
| // LookupStatic looks up the static symbol with name name. |
| // If it does not exist, it creates it. |
| func (ctxt *Link) LookupStatic(name string) *LSym { |
| s := ctxt.statichash[name] |
| if s == nil { |
| s = &LSym{Name: name, Attribute: AttrStatic} |
| ctxt.statichash[name] = s |
| } |
| return s |
| } |
| |
| // LookupABI looks up a symbol with the given ABI. |
| // If it does not exist, it creates it. |
| func (ctxt *Link) LookupABI(name string, abi ABI) *LSym { |
| return ctxt.LookupABIInit(name, abi, nil) |
| } |
| |
| // LookupABI looks up a symbol with the given ABI. |
| // If it does not exist, it creates it and |
| // passes it to init for one-time initialization. |
| func (ctxt *Link) LookupABIInit(name string, abi ABI, init func(s *LSym)) *LSym { |
| var hash map[string]*LSym |
| switch abi { |
| case ABI0: |
| hash = ctxt.hash |
| case ABIInternal: |
| hash = ctxt.funchash |
| default: |
| panic("unknown ABI") |
| } |
| |
| ctxt.hashmu.Lock() |
| s := hash[name] |
| if s == nil { |
| s = &LSym{Name: name} |
| s.SetABI(abi) |
| hash[name] = s |
| if init != nil { |
| init(s) |
| } |
| } |
| ctxt.hashmu.Unlock() |
| return s |
| } |
| |
| // Lookup looks up the symbol with name name. |
| // If it does not exist, it creates it. |
| func (ctxt *Link) Lookup(name string) *LSym { |
| return ctxt.LookupInit(name, nil) |
| } |
| |
| // LookupInit looks up the symbol with name name. |
| // If it does not exist, it creates it and |
| // passes it to init for one-time initialization. |
| func (ctxt *Link) LookupInit(name string, init func(s *LSym)) *LSym { |
| ctxt.hashmu.Lock() |
| s := ctxt.hash[name] |
| if s == nil { |
| s = &LSym{Name: name} |
| ctxt.hash[name] = s |
| if init != nil { |
| init(s) |
| } |
| } |
| ctxt.hashmu.Unlock() |
| return s |
| } |
| |
| func (ctxt *Link) Float32Sym(f float32) *LSym { |
| i := math.Float32bits(f) |
| name := fmt.Sprintf("$f32.%08x", i) |
| return ctxt.LookupInit(name, func(s *LSym) { |
| s.Size = 4 |
| s.WriteFloat32(ctxt, 0, f) |
| s.Type = objabi.SRODATA |
| s.Set(AttrLocal, true) |
| s.Set(AttrContentAddressable, true) |
| ctxt.constSyms = append(ctxt.constSyms, s) |
| }) |
| } |
| |
| func (ctxt *Link) Float64Sym(f float64) *LSym { |
| i := math.Float64bits(f) |
| name := fmt.Sprintf("$f64.%016x", i) |
| return ctxt.LookupInit(name, func(s *LSym) { |
| s.Size = 8 |
| s.WriteFloat64(ctxt, 0, f) |
| s.Type = objabi.SRODATA |
| s.Set(AttrLocal, true) |
| s.Set(AttrContentAddressable, true) |
| ctxt.constSyms = append(ctxt.constSyms, s) |
| }) |
| } |
| |
| func (ctxt *Link) Int64Sym(i int64) *LSym { |
| name := fmt.Sprintf("$i64.%016x", uint64(i)) |
| return ctxt.LookupInit(name, func(s *LSym) { |
| s.Size = 8 |
| s.WriteInt(ctxt, 0, 8, i) |
| s.Type = objabi.SRODATA |
| s.Set(AttrLocal, true) |
| s.Set(AttrContentAddressable, true) |
| ctxt.constSyms = append(ctxt.constSyms, s) |
| }) |
| } |
| |
| // GCLocalsSym generates a content-addressable sym containing data. |
| func (ctxt *Link) GCLocalsSym(data []byte) *LSym { |
| return ctxt.LookupInit(fmt.Sprintf("gclocals·%x", md5.Sum(data)), func(lsym *LSym) { |
| lsym.P = data |
| lsym.Set(AttrContentAddressable, true) |
| }) |
| } |
| |
| // Assign index to symbols. |
| // asm is set to true if this is called by the assembler (i.e. not the compiler), |
| // in which case all the symbols are non-package (for now). |
| func (ctxt *Link) NumberSyms() { |
| if ctxt.Headtype == objabi.Haix { |
| // Data must be sorted to keep a constant order in TOC symbols. |
| // As they are created during Progedit, two symbols can be switched between |
| // two different compilations. Therefore, BuildID will be different. |
| // TODO: find a better place and optimize to only sort TOC symbols |
| sort.Slice(ctxt.Data, func(i, j int) bool { |
| return ctxt.Data[i].Name < ctxt.Data[j].Name |
| }) |
| } |
| |
| // Constant symbols are created late in the concurrent phase. Sort them |
| // to ensure a deterministic order. |
| sort.Slice(ctxt.constSyms, func(i, j int) bool { |
| return ctxt.constSyms[i].Name < ctxt.constSyms[j].Name |
| }) |
| ctxt.Data = append(ctxt.Data, ctxt.constSyms...) |
| ctxt.constSyms = nil |
| |
| ctxt.pkgIdx = make(map[string]int32) |
| ctxt.defs = []*LSym{} |
| ctxt.hashed64defs = []*LSym{} |
| ctxt.hasheddefs = []*LSym{} |
| ctxt.nonpkgdefs = []*LSym{} |
| |
| var idx, hashedidx, hashed64idx, nonpkgidx int32 |
| ctxt.traverseSyms(traverseDefs|traversePcdata, func(s *LSym) { |
| // if Pkgpath is unknown, cannot hash symbols with relocations, as it |
| // may reference named symbols whose names are not fully expanded. |
| if s.ContentAddressable() && (ctxt.Pkgpath != "" || len(s.R) == 0) { |
| if s.Size <= 8 && len(s.R) == 0 && contentHashSection(s) == 0 { |
| // We can use short hash only for symbols without relocations. |
| // Don't use short hash for symbols that belong in a particular section |
| // or require special handling (such as type symbols). |
| s.PkgIdx = goobj.PkgIdxHashed64 |
| s.SymIdx = hashed64idx |
| if hashed64idx != int32(len(ctxt.hashed64defs)) { |
| panic("bad index") |
| } |
| ctxt.hashed64defs = append(ctxt.hashed64defs, s) |
| hashed64idx++ |
| } else { |
| s.PkgIdx = goobj.PkgIdxHashed |
| s.SymIdx = hashedidx |
| if hashedidx != int32(len(ctxt.hasheddefs)) { |
| panic("bad index") |
| } |
| ctxt.hasheddefs = append(ctxt.hasheddefs, s) |
| hashedidx++ |
| } |
| } else if isNonPkgSym(ctxt, s) { |
| s.PkgIdx = goobj.PkgIdxNone |
| s.SymIdx = nonpkgidx |
| if nonpkgidx != int32(len(ctxt.nonpkgdefs)) { |
| panic("bad index") |
| } |
| ctxt.nonpkgdefs = append(ctxt.nonpkgdefs, s) |
| nonpkgidx++ |
| } else { |
| s.PkgIdx = goobj.PkgIdxSelf |
| s.SymIdx = idx |
| if idx != int32(len(ctxt.defs)) { |
| panic("bad index") |
| } |
| ctxt.defs = append(ctxt.defs, s) |
| idx++ |
| } |
| s.Set(AttrIndexed, true) |
| }) |
| |
| ipkg := int32(1) // 0 is invalid index |
| nonpkgdef := nonpkgidx |
| ctxt.traverseSyms(traverseRefs|traverseAux, func(rs *LSym) { |
| if rs.PkgIdx != goobj.PkgIdxInvalid { |
| return |
| } |
| if !ctxt.Flag_linkshared { |
| // Assign special index for builtin symbols. |
| // Don't do it when linking against shared libraries, as the runtime |
| // may be in a different library. |
| if i := goobj.BuiltinIdx(rs.Name, int(rs.ABI())); i != -1 { |
| rs.PkgIdx = goobj.PkgIdxBuiltin |
| rs.SymIdx = int32(i) |
| rs.Set(AttrIndexed, true) |
| return |
| } |
| } |
| pkg := rs.Pkg |
| if rs.ContentAddressable() { |
| // for now, only support content-addressable symbols that are always locally defined. |
| panic("hashed refs unsupported for now") |
| } |
| if pkg == "" || pkg == "\"\"" || pkg == "_" || !rs.Indexed() { |
| rs.PkgIdx = goobj.PkgIdxNone |
| rs.SymIdx = nonpkgidx |
| rs.Set(AttrIndexed, true) |
| if nonpkgidx != nonpkgdef+int32(len(ctxt.nonpkgrefs)) { |
| panic("bad index") |
| } |
| ctxt.nonpkgrefs = append(ctxt.nonpkgrefs, rs) |
| nonpkgidx++ |
| return |
| } |
| if k, ok := ctxt.pkgIdx[pkg]; ok { |
| rs.PkgIdx = k |
| return |
| } |
| rs.PkgIdx = ipkg |
| ctxt.pkgIdx[pkg] = ipkg |
| ipkg++ |
| }) |
| } |
| |
| // Returns whether s is a non-package symbol, which needs to be referenced |
| // by name instead of by index. |
| func isNonPkgSym(ctxt *Link, s *LSym) bool { |
| if ctxt.IsAsm && !s.Static() { |
| // asm symbols are referenced by name only, except static symbols |
| // which are file-local and can be referenced by index. |
| return true |
| } |
| if ctxt.Flag_linkshared { |
| // The referenced symbol may be in a different shared library so |
| // the linker cannot see its index. |
| return true |
| } |
| if s.Pkg == "_" { |
| // The frontend uses package "_" to mark symbols that should not |
| // be referenced by index, e.g. linkname'd symbols. |
| return true |
| } |
| if s.DuplicateOK() { |
| // Dupok symbol needs to be dedup'd by name. |
| return true |
| } |
| return false |
| } |
| |
| // StaticNamePref is the prefix the front end applies to static temporary |
| // variables. When turned into LSyms, these can be tagged as static so |
| // as to avoid inserting them into the linker's name lookup tables. |
| const StaticNamePref = ".stmp_" |
| |
| type traverseFlag uint32 |
| |
| const ( |
| traverseDefs traverseFlag = 1 << iota |
| traverseRefs |
| traverseAux |
| traversePcdata |
| |
| traverseAll = traverseDefs | traverseRefs | traverseAux | traversePcdata |
| ) |
| |
| // Traverse symbols based on flag, call fn for each symbol. |
| func (ctxt *Link) traverseSyms(flag traverseFlag, fn func(*LSym)) { |
| fnNoNil := func(s *LSym) { |
| if s != nil { |
| fn(s) |
| } |
| } |
| lists := [][]*LSym{ctxt.Text, ctxt.Data} |
| for _, list := range lists { |
| for _, s := range list { |
| if flag&traverseDefs != 0 { |
| fn(s) |
| } |
| if flag&traverseRefs != 0 { |
| for _, r := range s.R { |
| fnNoNil(r.Sym) |
| } |
| } |
| if flag&traverseAux != 0 { |
| fnNoNil(s.Gotype) |
| if s.Type == objabi.STEXT { |
| f := func(parent *LSym, aux *LSym) { |
| fn(aux) |
| } |
| ctxt.traverseFuncAux(flag, s, f) |
| } |
| } |
| if flag&traversePcdata != 0 && s.Type == objabi.STEXT { |
| fi := s.Func().Pcln |
| fnNoNil(fi.Pcsp) |
| fnNoNil(fi.Pcfile) |
| fnNoNil(fi.Pcline) |
| fnNoNil(fi.Pcinline) |
| for _, d := range fi.Pcdata { |
| fnNoNil(d) |
| } |
| } |
| } |
| } |
| } |
| |
| func (ctxt *Link) traverseFuncAux(flag traverseFlag, fsym *LSym, fn func(parent *LSym, aux *LSym)) { |
| fninfo := fsym.Func() |
| pc := &fninfo.Pcln |
| if flag&traverseAux == 0 { |
| // NB: should it become necessary to walk aux sym reloc references |
| // without walking the aux syms themselves, this can be changed. |
| panic("should not be here") |
| } |
| for _, d := range pc.Funcdata { |
| if d != nil { |
| fn(fsym, d) |
| } |
| } |
| files := ctxt.PosTable.FileTable() |
| usedFiles := make([]goobj.CUFileIndex, 0, len(pc.UsedFiles)) |
| for f := range pc.UsedFiles { |
| usedFiles = append(usedFiles, f) |
| } |
| sort.Slice(usedFiles, func(i, j int) bool { return usedFiles[i] < usedFiles[j] }) |
| for _, f := range usedFiles { |
| if filesym := ctxt.Lookup(files[f]); filesym != nil { |
| fn(fsym, filesym) |
| } |
| } |
| for _, call := range pc.InlTree.nodes { |
| if call.Func != nil { |
| fn(fsym, call.Func) |
| } |
| f, _ := linkgetlineFromPos(ctxt, call.Pos) |
| if filesym := ctxt.Lookup(f); filesym != nil { |
| fn(fsym, filesym) |
| } |
| } |
| |
| dwsyms := []*LSym{fninfo.dwarfRangesSym, fninfo.dwarfLocSym, fninfo.dwarfDebugLinesSym, fninfo.dwarfInfoSym} |
| for _, dws := range dwsyms { |
| if dws == nil || dws.Size == 0 { |
| continue |
| } |
| fn(fsym, dws) |
| if flag&traverseRefs != 0 { |
| for _, r := range dws.R { |
| if r.Sym != nil { |
| fn(dws, r.Sym) |
| } |
| } |
| } |
| } |
| } |
| |
| // Traverse aux symbols, calling fn for each sym/aux pair. |
| func (ctxt *Link) traverseAuxSyms(flag traverseFlag, fn func(parent *LSym, aux *LSym)) { |
| lists := [][]*LSym{ctxt.Text, ctxt.Data} |
| for _, list := range lists { |
| for _, s := range list { |
| if s.Gotype != nil { |
| if flag&traverseDefs != 0 { |
| fn(s, s.Gotype) |
| } |
| } |
| if s.Type != objabi.STEXT { |
| continue |
| } |
| ctxt.traverseFuncAux(flag, s, fn) |
| } |
| } |
| } |
