| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package gc |
| |
| import ( |
| "cmd/compile/internal/types" |
| "cmd/internal/bio" |
| "cmd/internal/obj" |
| "cmd/internal/objabi" |
| "cmd/internal/src" |
| "crypto/sha256" |
| "encoding/json" |
| "fmt" |
| "io" |
| "sort" |
| "strconv" |
| ) |
| |
| // architecture-independent object file output |
| const ArhdrSize = 60 |
| |
| func formathdr(arhdr []byte, name string, size int64) { |
| copy(arhdr[:], fmt.Sprintf("%-16s%-12d%-6d%-6d%-8o%-10d`\n", name, 0, 0, 0, 0644, size)) |
| } |
| |
| // These modes say which kind of object file to generate. |
| // The default use of the toolchain is to set both bits, |
| // generating a combined compiler+linker object, one that |
| // serves to describe the package to both the compiler and the linker. |
| // In fact the compiler and linker read nearly disjoint sections of |
| // that file, though, so in a distributed build setting it can be more |
| // efficient to split the output into two files, supplying the compiler |
| // object only to future compilations and the linker object only to |
| // future links. |
| // |
| // By default a combined object is written, but if -linkobj is specified |
| // on the command line then the default -o output is a compiler object |
| // and the -linkobj output is a linker object. |
| const ( |
| modeCompilerObj = 1 << iota |
| modeLinkerObj |
| ) |
| |
| func dumpobj() { |
| if linkobj == "" { |
| dumpobj1(outfile, modeCompilerObj|modeLinkerObj) |
| return |
| } |
| dumpobj1(outfile, modeCompilerObj) |
| dumpobj1(linkobj, modeLinkerObj) |
| } |
| |
| func dumpobj1(outfile string, mode int) { |
| bout, err := bio.Create(outfile) |
| if err != nil { |
| flusherrors() |
| fmt.Printf("can't create %s: %v\n", outfile, err) |
| errorexit() |
| } |
| defer bout.Close() |
| bout.WriteString("!<arch>\n") |
| |
| if mode&modeCompilerObj != 0 { |
| start := startArchiveEntry(bout) |
| dumpCompilerObj(bout) |
| finishArchiveEntry(bout, start, "__.PKGDEF") |
| } |
| if mode&modeLinkerObj != 0 { |
| start := startArchiveEntry(bout) |
| dumpLinkerObj(bout) |
| finishArchiveEntry(bout, start, "_go_.o") |
| } |
| } |
| |
| func printObjHeader(bout *bio.Writer) { |
| fmt.Fprintf(bout, "go object %s %s %s %s\n", objabi.GOOS, objabi.GOARCH, objabi.Version, objabi.Expstring()) |
| if buildid != "" { |
| fmt.Fprintf(bout, "build id %q\n", buildid) |
| } |
| if localpkg.Name == "main" { |
| fmt.Fprintf(bout, "main\n") |
| } |
| fmt.Fprintf(bout, "\n") // header ends with blank line |
| } |
| |
| func startArchiveEntry(bout *bio.Writer) int64 { |
| var arhdr [ArhdrSize]byte |
| bout.Write(arhdr[:]) |
| return bout.Offset() |
| } |
| |
| func finishArchiveEntry(bout *bio.Writer, start int64, name string) { |
| bout.Flush() |
| size := bout.Offset() - start |
| if size&1 != 0 { |
| bout.WriteByte(0) |
| } |
| bout.MustSeek(start-ArhdrSize, 0) |
| |
| var arhdr [ArhdrSize]byte |
| formathdr(arhdr[:], name, size) |
| bout.Write(arhdr[:]) |
| bout.Flush() |
| bout.MustSeek(start+size+(size&1), 0) |
| } |
| |
| func dumpCompilerObj(bout *bio.Writer) { |
| printObjHeader(bout) |
| dumpexport(bout) |
| } |
| |
| func dumpdata() { |
| externs := len(externdcl) |
| xtops := len(xtop) |
| |
| dumpglobls() |
| addptabs() |
| exportlistLen := len(exportlist) |
| addsignats(externdcl) |
| dumpsignats() |
| dumptabs() |
| ptabsLen := len(ptabs) |
| itabsLen := len(itabs) |
| dumpimportstrings() |
| dumpbasictypes() |
| |
| // Calls to dumpsignats can generate functions, |
| // like method wrappers and hash and equality routines. |
| // Compile any generated functions, process any new resulting types, repeat. |
| // This can't loop forever, because there is no way to generate an infinite |
| // number of types in a finite amount of code. |
| // In the typical case, we loop 0 or 1 times. |
| // It was not until issue 24761 that we found any code that required a loop at all. |
| for { |
| for i := xtops; i < len(xtop); i++ { |
| n := xtop[i] |
| if n.Op == ODCLFUNC { |
| funccompile(n) |
| } |
| } |
| xtops = len(xtop) |
| compileFunctions() |
| dumpsignats() |
| if xtops == len(xtop) { |
| break |
| } |
| } |
| |
| // Dump extra globals. |
| tmp := externdcl |
| |
| if externdcl != nil { |
| externdcl = externdcl[externs:] |
| } |
| dumpglobls() |
| externdcl = tmp |
| |
| if zerosize > 0 { |
| zero := mappkg.Lookup("zero") |
| ggloblsym(zero.Linksym(), int32(zerosize), obj.DUPOK|obj.RODATA) |
| } |
| |
| addGCLocals() |
| |
| if exportlistLen != len(exportlist) { |
| Fatalf("exportlist changed after compile functions loop") |
| } |
| if ptabsLen != len(ptabs) { |
| Fatalf("ptabs changed after compile functions loop") |
| } |
| if itabsLen != len(itabs) { |
| Fatalf("itabs changed after compile functions loop") |
| } |
| } |
| |
| func dumpLinkerObj(bout *bio.Writer) { |
| printObjHeader(bout) |
| |
| if len(pragcgobuf) != 0 { |
| // write empty export section; must be before cgo section |
| fmt.Fprintf(bout, "\n$$\n\n$$\n\n") |
| fmt.Fprintf(bout, "\n$$ // cgo\n") |
| if err := json.NewEncoder(bout).Encode(pragcgobuf); err != nil { |
| Fatalf("serializing pragcgobuf: %v", err) |
| } |
| fmt.Fprintf(bout, "\n$$\n\n") |
| } |
| |
| fmt.Fprintf(bout, "\n!\n") |
| |
| obj.WriteObjFile(Ctxt, bout) |
| } |
| |
| func addptabs() { |
| if !Ctxt.Flag_dynlink || localpkg.Name != "main" { |
| return |
| } |
| for _, exportn := range exportlist { |
| s := exportn.Sym |
| n := asNode(s.Def) |
| if n == nil { |
| continue |
| } |
| if n.Op != ONAME { |
| continue |
| } |
| if !types.IsExported(s.Name) { |
| continue |
| } |
| if s.Pkg.Name != "main" { |
| continue |
| } |
| if n.Type.Etype == TFUNC && n.Class() == PFUNC { |
| // function |
| ptabs = append(ptabs, ptabEntry{s: s, t: asNode(s.Def).Type}) |
| } else { |
| // variable |
| ptabs = append(ptabs, ptabEntry{s: s, t: types.NewPtr(asNode(s.Def).Type)}) |
| } |
| } |
| } |
| |
| func dumpGlobal(n *Node) { |
| if n.Type == nil { |
| Fatalf("external %v nil type\n", n) |
| } |
| if n.Class() == PFUNC { |
| return |
| } |
| if n.Sym.Pkg != localpkg { |
| return |
| } |
| dowidth(n.Type) |
| ggloblnod(n) |
| } |
| |
| func dumpGlobalConst(n *Node) { |
| // only export typed constants |
| t := n.Type |
| if t == nil { |
| return |
| } |
| if n.Sym.Pkg != localpkg { |
| return |
| } |
| // only export integer constants for now |
| switch t.Etype { |
| case TINT8: |
| case TINT16: |
| case TINT32: |
| case TINT64: |
| case TINT: |
| case TUINT8: |
| case TUINT16: |
| case TUINT32: |
| case TUINT64: |
| case TUINT: |
| case TUINTPTR: |
| // ok |
| case TIDEAL: |
| if !Isconst(n, CTINT) { |
| return |
| } |
| x := n.Val().U.(*Mpint) |
| if x.Cmp(minintval[TINT]) < 0 || x.Cmp(maxintval[TINT]) > 0 { |
| return |
| } |
| // Ideal integers we export as int (if they fit). |
| t = types.Types[TINT] |
| default: |
| return |
| } |
| Ctxt.DwarfIntConst(myimportpath, n.Sym.Name, typesymname(t), n.Int64()) |
| } |
| |
| func dumpglobls() { |
| // add globals |
| for _, n := range externdcl { |
| switch n.Op { |
| case ONAME: |
| dumpGlobal(n) |
| case OLITERAL: |
| dumpGlobalConst(n) |
| } |
| } |
| |
| sort.Slice(funcsyms, func(i, j int) bool { |
| return funcsyms[i].LinksymName() < funcsyms[j].LinksymName() |
| }) |
| for _, s := range funcsyms { |
| sf := s.Pkg.Lookup(funcsymname(s)).Linksym() |
| dsymptr(sf, 0, s.Linksym(), 0) |
| ggloblsym(sf, int32(Widthptr), obj.DUPOK|obj.RODATA) |
| } |
| |
| // Do not reprocess funcsyms on next dumpglobls call. |
| funcsyms = nil |
| } |
| |
| // addGCLocals adds gcargs, gclocals, gcregs, and stack object symbols to Ctxt.Data. |
| // |
| // This is done during the sequential phase after compilation, since |
| // global symbols can't be declared during parallel compilation. |
| func addGCLocals() { |
| for _, s := range Ctxt.Text { |
| if s.Func == nil { |
| continue |
| } |
| for _, gcsym := range []*obj.LSym{s.Func.GCArgs, s.Func.GCLocals, s.Func.GCRegs} { |
| if gcsym != nil && !gcsym.OnList() { |
| ggloblsym(gcsym, int32(len(gcsym.P)), obj.RODATA|obj.DUPOK) |
| } |
| } |
| if x := s.Func.StackObjects; x != nil { |
| attr := int16(obj.RODATA) |
| ggloblsym(x, int32(len(x.P)), attr) |
| x.Set(obj.AttrStatic, true) |
| } |
| if x := s.Func.OpenCodedDeferInfo; x != nil { |
| ggloblsym(x, int32(len(x.P)), obj.RODATA|obj.DUPOK) |
| } |
| } |
| } |
| |
| func duintxx(s *obj.LSym, off int, v uint64, wid int) int { |
| if off&(wid-1) != 0 { |
| Fatalf("duintxxLSym: misaligned: v=%d wid=%d off=%d", v, wid, off) |
| } |
| s.WriteInt(Ctxt, int64(off), wid, int64(v)) |
| return off + wid |
| } |
| |
| func duint8(s *obj.LSym, off int, v uint8) int { |
| return duintxx(s, off, uint64(v), 1) |
| } |
| |
| func duint16(s *obj.LSym, off int, v uint16) int { |
| return duintxx(s, off, uint64(v), 2) |
| } |
| |
| func duint32(s *obj.LSym, off int, v uint32) int { |
| return duintxx(s, off, uint64(v), 4) |
| } |
| |
| func duintptr(s *obj.LSym, off int, v uint64) int { |
| return duintxx(s, off, v, Widthptr) |
| } |
| |
| func dbvec(s *obj.LSym, off int, bv bvec) int { |
| // Runtime reads the bitmaps as byte arrays. Oblige. |
| for j := 0; int32(j) < bv.n; j += 8 { |
| word := bv.b[j/32] |
| off = duint8(s, off, uint8(word>>(uint(j)%32))) |
| } |
| return off |
| } |
| |
| func stringsym(pos src.XPos, s string) (data *obj.LSym) { |
| var symname string |
| if len(s) > 100 { |
| // Huge strings are hashed to avoid long names in object files. |
| // Indulge in some paranoia by writing the length of s, too, |
| // as protection against length extension attacks. |
| h := sha256.New() |
| io.WriteString(h, s) |
| symname = fmt.Sprintf(".gostring.%d.%x", len(s), h.Sum(nil)) |
| } else { |
| // Small strings get named directly by their contents. |
| symname = strconv.Quote(s) |
| } |
| |
| const prefix = "go.string." |
| symdataname := prefix + symname |
| |
| symdata := Ctxt.Lookup(symdataname) |
| |
| if !symdata.OnList() { |
| // string data |
| off := dsname(symdata, 0, s, pos, "string") |
| ggloblsym(symdata, int32(off), obj.DUPOK|obj.RODATA|obj.LOCAL) |
| symdata.Set(obj.AttrContentAddressable, true) |
| } |
| |
| return symdata |
| } |
| |
| var slicebytes_gen int |
| |
| func slicebytes(nam *Node, s string) { |
| slicebytes_gen++ |
| symname := fmt.Sprintf(".gobytes.%d", slicebytes_gen) |
| sym := localpkg.Lookup(symname) |
| symnode := newname(sym) |
| sym.Def = asTypesNode(symnode) |
| |
| lsym := sym.Linksym() |
| off := dsname(lsym, 0, s, nam.Pos, "slice") |
| ggloblsym(lsym, int32(off), obj.NOPTR|obj.LOCAL) |
| |
| if nam.Op != ONAME { |
| Fatalf("slicebytes %v", nam) |
| } |
| slicesym(nam, symnode, int64(len(s))) |
| } |
| |
| func dsname(s *obj.LSym, off int, t string, pos src.XPos, what string) int { |
| // Objects that are too large will cause the data section to overflow right away, |
| // causing a cryptic error message by the linker. Check for oversize objects here |
| // and provide a useful error message instead. |
| if int64(len(t)) > 2e9 { |
| yyerrorl(pos, "%v with length %v is too big", what, len(t)) |
| return 0 |
| } |
| |
| s.WriteString(Ctxt, int64(off), len(t), t) |
| return off + len(t) |
| } |
| |
| func dsymptr(s *obj.LSym, off int, x *obj.LSym, xoff int) int { |
| off = int(Rnd(int64(off), int64(Widthptr))) |
| s.WriteAddr(Ctxt, int64(off), Widthptr, x, int64(xoff)) |
| off += Widthptr |
| return off |
| } |
| |
| func dsymptrOff(s *obj.LSym, off int, x *obj.LSym) int { |
| s.WriteOff(Ctxt, int64(off), x, 0) |
| off += 4 |
| return off |
| } |
| |
| func dsymptrWeakOff(s *obj.LSym, off int, x *obj.LSym) int { |
| s.WriteWeakOff(Ctxt, int64(off), x, 0) |
| off += 4 |
| return off |
| } |
| |
| // slicesym writes a static slice symbol {&arr, lencap, lencap} to n. |
| // arr must be an ONAME. slicesym does not modify n. |
| func slicesym(n, arr *Node, lencap int64) { |
| s := n.Sym.Linksym() |
| base := n.Xoffset |
| if arr.Op != ONAME { |
| Fatalf("slicesym non-name arr %v", arr) |
| } |
| s.WriteAddr(Ctxt, base, Widthptr, arr.Sym.Linksym(), arr.Xoffset) |
| s.WriteInt(Ctxt, base+sliceLenOffset, Widthptr, lencap) |
| s.WriteInt(Ctxt, base+sliceCapOffset, Widthptr, lencap) |
| } |
| |
| // addrsym writes the static address of a to n. a must be an ONAME. |
| // Neither n nor a is modified. |
| func addrsym(n, a *Node) { |
| if n.Op != ONAME { |
| Fatalf("addrsym n op %v", n.Op) |
| } |
| if n.Sym == nil { |
| Fatalf("addrsym nil n sym") |
| } |
| if a.Op != ONAME { |
| Fatalf("addrsym a op %v", a.Op) |
| } |
| s := n.Sym.Linksym() |
| s.WriteAddr(Ctxt, n.Xoffset, Widthptr, a.Sym.Linksym(), a.Xoffset) |
| } |
| |
| // pfuncsym writes the static address of f to n. f must be a global function. |
| // Neither n nor f is modified. |
| func pfuncsym(n, f *Node) { |
| if n.Op != ONAME { |
| Fatalf("pfuncsym n op %v", n.Op) |
| } |
| if n.Sym == nil { |
| Fatalf("pfuncsym nil n sym") |
| } |
| if f.Class() != PFUNC { |
| Fatalf("pfuncsym class not PFUNC %d", f.Class()) |
| } |
| s := n.Sym.Linksym() |
| s.WriteAddr(Ctxt, n.Xoffset, Widthptr, funcsym(f.Sym).Linksym(), f.Xoffset) |
| } |
| |
| // litsym writes the static literal c to n. |
| // Neither n nor c is modified. |
| func litsym(n, c *Node, wid int) { |
| if n.Op != ONAME { |
| Fatalf("litsym n op %v", n.Op) |
| } |
| if c.Op != OLITERAL { |
| Fatalf("litsym c op %v", c.Op) |
| } |
| if n.Sym == nil { |
| Fatalf("litsym nil n sym") |
| } |
| s := n.Sym.Linksym() |
| switch u := c.Val().U.(type) { |
| case bool: |
| i := int64(obj.Bool2int(u)) |
| s.WriteInt(Ctxt, n.Xoffset, wid, i) |
| |
| case *Mpint: |
| s.WriteInt(Ctxt, n.Xoffset, wid, u.Int64()) |
| |
| case *Mpflt: |
| f := u.Float64() |
| switch n.Type.Etype { |
| case TFLOAT32: |
| s.WriteFloat32(Ctxt, n.Xoffset, float32(f)) |
| case TFLOAT64: |
| s.WriteFloat64(Ctxt, n.Xoffset, f) |
| } |
| |
| case *Mpcplx: |
| r := u.Real.Float64() |
| i := u.Imag.Float64() |
| switch n.Type.Etype { |
| case TCOMPLEX64: |
| s.WriteFloat32(Ctxt, n.Xoffset, float32(r)) |
| s.WriteFloat32(Ctxt, n.Xoffset+4, float32(i)) |
| case TCOMPLEX128: |
| s.WriteFloat64(Ctxt, n.Xoffset, r) |
| s.WriteFloat64(Ctxt, n.Xoffset+8, i) |
| } |
| |
| case string: |
| symdata := stringsym(n.Pos, u) |
| s.WriteAddr(Ctxt, n.Xoffset, Widthptr, symdata, 0) |
| s.WriteInt(Ctxt, n.Xoffset+int64(Widthptr), Widthptr, int64(len(u))) |
| |
| default: |
| Fatalf("litsym unhandled OLITERAL %v", c) |
| } |
| } |
