| // Derived from Inferno utils/6l/obj.c and utils/6l/span.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/obj.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/default/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 ld |
| |
| import ( |
| "cmd/internal/gcprog" |
| "cmd/internal/objabi" |
| "cmd/internal/sys" |
| "fmt" |
| "log" |
| "os" |
| "sort" |
| "strconv" |
| "strings" |
| "sync" |
| ) |
| |
| func Symgrow(s *Symbol, siz int64) { |
| if int64(int(siz)) != siz { |
| log.Fatalf("symgrow size %d too long", siz) |
| } |
| if int64(len(s.P)) >= siz { |
| return |
| } |
| if cap(s.P) < int(siz) { |
| p := make([]byte, 2*(siz+1)) |
| s.P = append(p[:0], s.P...) |
| } |
| s.P = s.P[:siz] |
| } |
| |
| func Addrel(s *Symbol) *Reloc { |
| s.R = append(s.R, Reloc{}) |
| return &s.R[len(s.R)-1] |
| } |
| |
| func setuintxx(ctxt *Link, s *Symbol, off int64, v uint64, wid int64) int64 { |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| if s.Size < off+wid { |
| s.Size = off + wid |
| Symgrow(s, s.Size) |
| } |
| |
| switch wid { |
| case 1: |
| s.P[off] = uint8(v) |
| case 2: |
| ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(v)) |
| case 4: |
| ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(v)) |
| case 8: |
| ctxt.Arch.ByteOrder.PutUint64(s.P[off:], v) |
| } |
| |
| return off + wid |
| } |
| |
| func Addbytes(s *Symbol, bytes []byte) int64 { |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| s.P = append(s.P, bytes...) |
| s.Size = int64(len(s.P)) |
| |
| return s.Size |
| } |
| |
| func adduintxx(ctxt *Link, s *Symbol, v uint64, wid int) int64 { |
| off := s.Size |
| setuintxx(ctxt, s, off, v, int64(wid)) |
| return off |
| } |
| |
| func Adduint8(ctxt *Link, s *Symbol, v uint8) int64 { |
| off := s.Size |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| s.Size++ |
| s.P = append(s.P, v) |
| |
| return off |
| } |
| |
| func Adduint16(ctxt *Link, s *Symbol, v uint16) int64 { |
| return adduintxx(ctxt, s, uint64(v), 2) |
| } |
| |
| func Adduint32(ctxt *Link, s *Symbol, v uint32) int64 { |
| return adduintxx(ctxt, s, uint64(v), 4) |
| } |
| |
| func Adduint64(ctxt *Link, s *Symbol, v uint64) int64 { |
| return adduintxx(ctxt, s, v, 8) |
| } |
| |
| func adduint(ctxt *Link, s *Symbol, v uint64) int64 { |
| return adduintxx(ctxt, s, v, SysArch.PtrSize) |
| } |
| |
| func setuint8(ctxt *Link, s *Symbol, r int64, v uint8) int64 { |
| return setuintxx(ctxt, s, r, uint64(v), 1) |
| } |
| |
| func setuint32(ctxt *Link, s *Symbol, r int64, v uint32) int64 { |
| return setuintxx(ctxt, s, r, uint64(v), 4) |
| } |
| |
| func setuint(ctxt *Link, s *Symbol, r int64, v uint64) int64 { |
| return setuintxx(ctxt, s, r, v, int64(SysArch.PtrSize)) |
| } |
| |
| func Addaddrplus(ctxt *Link, s *Symbol, t *Symbol, add int64) int64 { |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| i := s.Size |
| s.Size += int64(ctxt.Arch.PtrSize) |
| Symgrow(s, s.Size) |
| r := Addrel(s) |
| r.Sym = t |
| r.Off = int32(i) |
| r.Siz = uint8(ctxt.Arch.PtrSize) |
| r.Type = objabi.R_ADDR |
| r.Add = add |
| return i + int64(r.Siz) |
| } |
| |
| func Addpcrelplus(ctxt *Link, s *Symbol, t *Symbol, add int64) int64 { |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| i := s.Size |
| s.Size += 4 |
| Symgrow(s, s.Size) |
| r := Addrel(s) |
| r.Sym = t |
| r.Off = int32(i) |
| r.Add = add |
| r.Type = objabi.R_PCREL |
| r.Siz = 4 |
| if SysArch.Family == sys.S390X { |
| r.Variant = RV_390_DBL |
| } |
| return i + int64(r.Siz) |
| } |
| |
| func Addaddr(ctxt *Link, s *Symbol, t *Symbol) int64 { |
| return Addaddrplus(ctxt, s, t, 0) |
| } |
| |
| func setaddrplus(ctxt *Link, s *Symbol, off int64, t *Symbol, add int64) int64 { |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| if off+int64(ctxt.Arch.PtrSize) > s.Size { |
| s.Size = off + int64(ctxt.Arch.PtrSize) |
| Symgrow(s, s.Size) |
| } |
| |
| r := Addrel(s) |
| r.Sym = t |
| r.Off = int32(off) |
| r.Siz = uint8(ctxt.Arch.PtrSize) |
| r.Type = objabi.R_ADDR |
| r.Add = add |
| return off + int64(r.Siz) |
| } |
| |
| func setaddr(ctxt *Link, s *Symbol, off int64, t *Symbol) int64 { |
| return setaddrplus(ctxt, s, off, t, 0) |
| } |
| |
| func addsize(ctxt *Link, s *Symbol, t *Symbol) int64 { |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| i := s.Size |
| s.Size += int64(ctxt.Arch.PtrSize) |
| Symgrow(s, s.Size) |
| r := Addrel(s) |
| r.Sym = t |
| r.Off = int32(i) |
| r.Siz = uint8(ctxt.Arch.PtrSize) |
| r.Type = objabi.R_SIZE |
| return i + int64(r.Siz) |
| } |
| |
| func addaddrplus4(ctxt *Link, s *Symbol, t *Symbol, add int64) int64 { |
| if s.Type == 0 { |
| s.Type = SDATA |
| } |
| s.Attr |= AttrReachable |
| i := s.Size |
| s.Size += 4 |
| Symgrow(s, s.Size) |
| r := Addrel(s) |
| r.Sym = t |
| r.Off = int32(i) |
| r.Siz = 4 |
| r.Type = objabi.R_ADDR |
| r.Add = add |
| return i + int64(r.Siz) |
| } |
| |
| /* |
| * divide-and-conquer list-link (by Sub) sort of Symbol* by Value. |
| * Used for sub-symbols when loading host objects (see e.g. ldelf.go). |
| */ |
| |
| func listsort(l *Symbol) *Symbol { |
| if l == nil || l.Sub == nil { |
| return l |
| } |
| |
| l1 := l |
| l2 := l |
| for { |
| l2 = l2.Sub |
| if l2 == nil { |
| break |
| } |
| l2 = l2.Sub |
| if l2 == nil { |
| break |
| } |
| l1 = l1.Sub |
| } |
| |
| l2 = l1.Sub |
| l1.Sub = nil |
| l1 = listsort(l) |
| l2 = listsort(l2) |
| |
| /* set up lead element */ |
| if l1.Value < l2.Value { |
| l = l1 |
| l1 = l1.Sub |
| } else { |
| l = l2 |
| l2 = l2.Sub |
| } |
| |
| le := l |
| |
| for { |
| if l1 == nil { |
| for l2 != nil { |
| le.Sub = l2 |
| le = l2 |
| l2 = l2.Sub |
| } |
| |
| le.Sub = nil |
| break |
| } |
| |
| if l2 == nil { |
| for l1 != nil { |
| le.Sub = l1 |
| le = l1 |
| l1 = l1.Sub |
| } |
| |
| break |
| } |
| |
| if l1.Value < l2.Value { |
| le.Sub = l1 |
| le = l1 |
| l1 = l1.Sub |
| } else { |
| le.Sub = l2 |
| le = l2 |
| l2 = l2.Sub |
| } |
| } |
| |
| le.Sub = nil |
| return l |
| } |
| |
| // isRuntimeDepPkg returns whether pkg is the runtime package or its dependency |
| func isRuntimeDepPkg(pkg string) bool { |
| switch pkg { |
| case "runtime", |
| "sync/atomic": // runtime may call to sync/atomic, due to go:linkname |
| return true |
| } |
| return strings.HasPrefix(pkg, "runtime/internal/") && !strings.HasSuffix(pkg, "_test") |
| } |
| |
| // Estimate the max size needed to hold any new trampolines created for this function. This |
| // is used to determine when the section can be split if it becomes too large, to ensure that |
| // the trampolines are in the same section as the function that uses them. |
| func maxSizeTrampolinesPPC64(s *Symbol, isTramp bool) uint64 { |
| // If Thearch.Trampoline is nil, then trampoline support is not available on this arch. |
| // A trampoline does not need any dependent trampolines. |
| if Thearch.Trampoline == nil || isTramp { |
| return 0 |
| } |
| |
| n := uint64(0) |
| for ri := range s.R { |
| r := &s.R[ri] |
| if r.Type.IsDirectJump() { |
| n++ |
| } |
| } |
| // Trampolines in ppc64 are 4 instructions. |
| return n * 16 |
| } |
| |
| // detect too-far jumps in function s, and add trampolines if necessary |
| // ARM, PPC64 & PPC64LE support trampoline insertion for internal and external linking |
| // On PPC64 & PPC64LE the text sections might be split but will still insert trampolines |
| // where necessary. |
| func trampoline(ctxt *Link, s *Symbol) { |
| if Thearch.Trampoline == nil { |
| return // no need or no support of trampolines on this arch |
| } |
| |
| for ri := range s.R { |
| r := &s.R[ri] |
| if !r.Type.IsDirectJump() { |
| continue |
| } |
| if Symaddr(r.Sym) == 0 && r.Sym.Type != SDYNIMPORT { |
| if r.Sym.File != s.File { |
| if !isRuntimeDepPkg(s.File) || !isRuntimeDepPkg(r.Sym.File) { |
| Errorf(s, "unresolved inter-package jump to %s(%s)", r.Sym, r.Sym.File) |
| } |
| // runtime and its dependent packages may call to each other. |
| // they are fine, as they will be laid down together. |
| } |
| continue |
| } |
| |
| Thearch.Trampoline(ctxt, r, s) |
| } |
| |
| } |
| |
| // resolve relocations in s. |
| func relocsym(ctxt *Link, s *Symbol) { |
| var r *Reloc |
| var rs *Symbol |
| var i16 int16 |
| var off int32 |
| var siz int32 |
| var fl int32 |
| var o int64 |
| |
| for ri := int32(0); ri < int32(len(s.R)); ri++ { |
| r = &s.R[ri] |
| |
| r.Done = 1 |
| off = r.Off |
| siz = int32(r.Siz) |
| if off < 0 || off+siz > int32(len(s.P)) { |
| rname := "" |
| if r.Sym != nil { |
| rname = r.Sym.Name |
| } |
| Errorf(s, "invalid relocation %s: %d+%d not in [%d,%d)", rname, off, siz, 0, len(s.P)) |
| continue |
| } |
| |
| if r.Sym != nil && (r.Sym.Type&(SMASK|SHIDDEN) == 0 || r.Sym.Type&SMASK == SXREF) { |
| // When putting the runtime but not main into a shared library |
| // these symbols are undefined and that's OK. |
| if Buildmode == BuildmodeShared { |
| if r.Sym.Name == "main.main" || r.Sym.Name == "main.init" { |
| r.Sym.Type = SDYNIMPORT |
| } else if strings.HasPrefix(r.Sym.Name, "go.info.") { |
| // Skip go.info symbols. They are only needed to communicate |
| // DWARF info between the compiler and linker. |
| continue |
| } |
| } else { |
| Errorf(s, "relocation target %s not defined", r.Sym.Name) |
| continue |
| } |
| } |
| |
| if r.Type >= 256 { |
| continue |
| } |
| if r.Siz == 0 { // informational relocation - no work to do |
| continue |
| } |
| |
| // We need to be able to reference dynimport symbols when linking against |
| // shared libraries, and Solaris needs it always |
| if Headtype != objabi.Hsolaris && r.Sym != nil && r.Sym.Type == SDYNIMPORT && !ctxt.DynlinkingGo() { |
| if !(SysArch.Family == sys.PPC64 && Linkmode == LinkExternal && r.Sym.Name == ".TOC.") { |
| Errorf(s, "unhandled relocation for %s (type %d rtype %d)", r.Sym.Name, r.Sym.Type, r.Type) |
| } |
| } |
| if r.Sym != nil && r.Sym.Type != STLSBSS && r.Type != objabi.R_WEAKADDROFF && !r.Sym.Attr.Reachable() { |
| Errorf(s, "unreachable sym in relocation: %s", r.Sym.Name) |
| } |
| |
| // TODO(mundaym): remove this special case - see issue 14218. |
| if SysArch.Family == sys.S390X { |
| switch r.Type { |
| case objabi.R_PCRELDBL: |
| r.Type = objabi.R_PCREL |
| r.Variant = RV_390_DBL |
| case objabi.R_CALL: |
| r.Variant = RV_390_DBL |
| } |
| } |
| |
| switch r.Type { |
| default: |
| switch siz { |
| default: |
| Errorf(s, "bad reloc size %#x for %s", uint32(siz), r.Sym.Name) |
| case 1: |
| o = int64(s.P[off]) |
| case 2: |
| o = int64(ctxt.Arch.ByteOrder.Uint16(s.P[off:])) |
| case 4: |
| o = int64(ctxt.Arch.ByteOrder.Uint32(s.P[off:])) |
| case 8: |
| o = int64(ctxt.Arch.ByteOrder.Uint64(s.P[off:])) |
| } |
| if Thearch.Archreloc(ctxt, r, s, &o) < 0 { |
| Errorf(s, "unknown reloc to %v: %v", r.Sym.Name, r.Type) |
| } |
| |
| case objabi.R_TLS_LE: |
| isAndroidX86 := objabi.GOOS == "android" && (SysArch.InFamily(sys.AMD64, sys.I386)) |
| |
| if Linkmode == LinkExternal && Iself && !isAndroidX86 { |
| r.Done = 0 |
| if r.Sym == nil { |
| r.Sym = ctxt.Tlsg |
| } |
| r.Xsym = r.Sym |
| r.Xadd = r.Add |
| o = 0 |
| if SysArch.Family != sys.AMD64 { |
| o = r.Add |
| } |
| break |
| } |
| |
| if Iself && SysArch.Family == sys.ARM { |
| // On ELF ARM, the thread pointer is 8 bytes before |
| // the start of the thread-local data block, so add 8 |
| // to the actual TLS offset (r->sym->value). |
| // This 8 seems to be a fundamental constant of |
| // ELF on ARM (or maybe Glibc on ARM); it is not |
| // related to the fact that our own TLS storage happens |
| // to take up 8 bytes. |
| o = 8 + r.Sym.Value |
| } else if Iself || Headtype == objabi.Hplan9 || Headtype == objabi.Hdarwin || isAndroidX86 { |
| o = int64(ctxt.Tlsoffset) + r.Add |
| } else if Headtype == objabi.Hwindows { |
| o = r.Add |
| } else { |
| log.Fatalf("unexpected R_TLS_LE relocation for %v", Headtype) |
| } |
| |
| case objabi.R_TLS_IE: |
| isAndroidX86 := objabi.GOOS == "android" && (SysArch.InFamily(sys.AMD64, sys.I386)) |
| |
| if Linkmode == LinkExternal && Iself && !isAndroidX86 { |
| r.Done = 0 |
| if r.Sym == nil { |
| r.Sym = ctxt.Tlsg |
| } |
| r.Xsym = r.Sym |
| r.Xadd = r.Add |
| o = 0 |
| if SysArch.Family != sys.AMD64 { |
| o = r.Add |
| } |
| break |
| } |
| if Buildmode == BuildmodePIE && Iself { |
| // We are linking the final executable, so we |
| // can optimize any TLS IE relocation to LE. |
| if Thearch.TLSIEtoLE == nil { |
| log.Fatalf("internal linking of TLS IE not supported on %v", SysArch.Family) |
| } |
| Thearch.TLSIEtoLE(s, int(off), int(r.Siz)) |
| o = int64(ctxt.Tlsoffset) |
| // TODO: o += r.Add when SysArch.Family != sys.AMD64? |
| // Why do we treat r.Add differently on AMD64? |
| // Is the external linker using Xadd at all? |
| } else { |
| log.Fatalf("cannot handle R_TLS_IE (sym %s) when linking internally", s.Name) |
| } |
| |
| case objabi.R_ADDR: |
| if Linkmode == LinkExternal && r.Sym.Type != SCONST { |
| r.Done = 0 |
| |
| // set up addend for eventual relocation via outer symbol. |
| rs = r.Sym |
| |
| r.Xadd = r.Add |
| for rs.Outer != nil { |
| r.Xadd += Symaddr(rs) - Symaddr(rs.Outer) |
| rs = rs.Outer |
| } |
| |
| if rs.Type != SHOSTOBJ && rs.Type != SDYNIMPORT && rs.Sect == nil { |
| Errorf(s, "missing section for relocation target %s", rs.Name) |
| } |
| r.Xsym = rs |
| |
| o = r.Xadd |
| if Iself { |
| if SysArch.Family == sys.AMD64 { |
| o = 0 |
| } |
| } else if Headtype == objabi.Hdarwin { |
| // ld64 for arm64 has a bug where if the address pointed to by o exists in the |
| // symbol table (dynid >= 0), or is inside a symbol that exists in the symbol |
| // table, then it will add o twice into the relocated value. |
| // The workaround is that on arm64 don't ever add symaddr to o and always use |
| // extern relocation by requiring rs->dynid >= 0. |
| if rs.Type != SHOSTOBJ { |
| if SysArch.Family == sys.ARM64 && rs.Dynid < 0 { |
| Errorf(s, "R_ADDR reloc to %s+%d is not supported on darwin/arm64", rs.Name, o) |
| } |
| if SysArch.Family != sys.ARM64 { |
| o += Symaddr(rs) |
| } |
| } |
| } else if Headtype == objabi.Hwindows { |
| // nothing to do |
| } else { |
| Errorf(s, "unhandled pcrel relocation to %s on %v", rs.Name, Headtype) |
| } |
| |
| break |
| } |
| |
| o = Symaddr(r.Sym) + r.Add |
| |
| // On amd64, 4-byte offsets will be sign-extended, so it is impossible to |
| // access more than 2GB of static data; fail at link time is better than |
| // fail at runtime. See https://golang.org/issue/7980. |
| // Instead of special casing only amd64, we treat this as an error on all |
| // 64-bit architectures so as to be future-proof. |
| if int32(o) < 0 && SysArch.PtrSize > 4 && siz == 4 { |
| Errorf(s, "non-pc-relative relocation address for %s is too big: %#x (%#x + %#x)", r.Sym.Name, uint64(o), Symaddr(r.Sym), r.Add) |
| errorexit() |
| } |
| |
| case objabi.R_DWARFREF: |
| var sectName string |
| var vaddr int64 |
| switch { |
| case r.Sym.Sect != nil: |
| sectName = r.Sym.Sect.Name |
| vaddr = int64(r.Sym.Sect.Vaddr) |
| case r.Sym.Type == SDWARFRANGE: |
| sectName = ".debug_ranges" |
| default: |
| Errorf(s, "missing DWARF section for relocation target %s", r.Sym.Name) |
| } |
| |
| if Linkmode == LinkExternal { |
| r.Done = 0 |
| // PE code emits IMAGE_REL_I386_SECREL and IMAGE_REL_AMD64_SECREL |
| // for R_DWARFREF relocations, while R_ADDR is replaced with |
| // IMAGE_REL_I386_DIR32, IMAGE_REL_AMD64_ADDR64 and IMAGE_REL_AMD64_ADDR32. |
| // Do not replace R_DWARFREF with R_ADDR for windows - |
| // let PE code emit correct relocations. |
| if Headtype != objabi.Hwindows { |
| r.Type = objabi.R_ADDR |
| } |
| |
| r.Xsym = ctxt.Syms.ROLookup(sectName, 0) |
| r.Xadd = r.Add + Symaddr(r.Sym) - vaddr |
| |
| o = r.Xadd |
| rs = r.Xsym |
| if Iself && SysArch.Family == sys.AMD64 { |
| o = 0 |
| } |
| break |
| } |
| o = Symaddr(r.Sym) + r.Add - vaddr |
| |
| case objabi.R_WEAKADDROFF: |
| if !r.Sym.Attr.Reachable() { |
| continue |
| } |
| fallthrough |
| case objabi.R_ADDROFF: |
| // The method offset tables using this relocation expect the offset to be relative |
| // to the start of the first text section, even if there are multiple. |
| |
| if r.Sym.Sect.Name == ".text" { |
| o = Symaddr(r.Sym) - int64(Segtext.Sections[0].Vaddr) + r.Add |
| } else { |
| o = Symaddr(r.Sym) - int64(r.Sym.Sect.Vaddr) + r.Add |
| } |
| |
| // r->sym can be null when CALL $(constant) is transformed from absolute PC to relative PC call. |
| case objabi.R_GOTPCREL: |
| if ctxt.DynlinkingGo() && Headtype == objabi.Hdarwin && r.Sym != nil && r.Sym.Type != SCONST { |
| r.Done = 0 |
| r.Xadd = r.Add |
| r.Xadd -= int64(r.Siz) // relative to address after the relocated chunk |
| r.Xsym = r.Sym |
| |
| o = r.Xadd |
| o += int64(r.Siz) |
| break |
| } |
| fallthrough |
| case objabi.R_CALL, objabi.R_PCREL: |
| if Linkmode == LinkExternal && r.Sym != nil && r.Sym.Type != SCONST && (r.Sym.Sect != s.Sect || r.Type == objabi.R_GOTPCREL) { |
| r.Done = 0 |
| |
| // set up addend for eventual relocation via outer symbol. |
| rs = r.Sym |
| |
| r.Xadd = r.Add |
| for rs.Outer != nil { |
| r.Xadd += Symaddr(rs) - Symaddr(rs.Outer) |
| rs = rs.Outer |
| } |
| |
| r.Xadd -= int64(r.Siz) // relative to address after the relocated chunk |
| if rs.Type != SHOSTOBJ && rs.Type != SDYNIMPORT && rs.Sect == nil { |
| Errorf(s, "missing section for relocation target %s", rs.Name) |
| } |
| r.Xsym = rs |
| |
| o = r.Xadd |
| if Iself { |
| if SysArch.Family == sys.AMD64 { |
| o = 0 |
| } |
| } else if Headtype == objabi.Hdarwin { |
| if r.Type == objabi.R_CALL { |
| if rs.Type != SHOSTOBJ { |
| o += int64(uint64(Symaddr(rs)) - rs.Sect.Vaddr) |
| } |
| o -= int64(r.Off) // relative to section offset, not symbol |
| } else if SysArch.Family == sys.ARM { |
| // see ../arm/asm.go:/machoreloc1 |
| o += Symaddr(rs) - int64(s.Value) - int64(r.Off) |
| } else { |
| o += int64(r.Siz) |
| } |
| } else if Headtype == objabi.Hwindows && SysArch.Family == sys.AMD64 { // only amd64 needs PCREL |
| // PE/COFF's PC32 relocation uses the address after the relocated |
| // bytes as the base. Compensate by skewing the addend. |
| o += int64(r.Siz) |
| } else { |
| Errorf(s, "unhandled pcrel relocation to %s on %v", rs.Name, Headtype) |
| } |
| |
| break |
| } |
| |
| o = 0 |
| if r.Sym != nil { |
| o += Symaddr(r.Sym) |
| } |
| |
| o += r.Add - (s.Value + int64(r.Off) + int64(r.Siz)) |
| |
| case objabi.R_SIZE: |
| o = r.Sym.Size + r.Add |
| } |
| |
| if r.Variant != RV_NONE { |
| o = Thearch.Archrelocvariant(ctxt, r, s, o) |
| } |
| |
| if false { |
| nam := "<nil>" |
| if r.Sym != nil { |
| nam = r.Sym.Name |
| } |
| fmt.Printf("relocate %s %#x (%#x+%#x, size %d) => %s %#x +%#x [type %d/%d, %x]\n", s.Name, s.Value+int64(off), s.Value, r.Off, r.Siz, nam, Symaddr(r.Sym), r.Add, r.Type, r.Variant, o) |
| } |
| switch siz { |
| default: |
| Errorf(s, "bad reloc size %#x for %s", uint32(siz), r.Sym.Name) |
| fallthrough |
| |
| // TODO(rsc): Remove. |
| case 1: |
| s.P[off] = byte(int8(o)) |
| |
| case 2: |
| if o != int64(int16(o)) { |
| Errorf(s, "relocation address for %s is too big: %#x", r.Sym.Name, o) |
| } |
| i16 = int16(o) |
| ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(i16)) |
| |
| case 4: |
| if r.Type == objabi.R_PCREL || r.Type == objabi.R_CALL { |
| if o != int64(int32(o)) { |
| Errorf(s, "pc-relative relocation address for %s is too big: %#x", r.Sym.Name, o) |
| } |
| } else { |
| if o != int64(int32(o)) && o != int64(uint32(o)) { |
| Errorf(s, "non-pc-relative relocation address for %s is too big: %#x", r.Sym.Name, uint64(o)) |
| } |
| } |
| |
| fl = int32(o) |
| ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(fl)) |
| |
| case 8: |
| ctxt.Arch.ByteOrder.PutUint64(s.P[off:], uint64(o)) |
| } |
| } |
| } |
| |
| func (ctxt *Link) reloc() { |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f reloc\n", Cputime()) |
| } |
| |
| for _, s := range ctxt.Textp { |
| relocsym(ctxt, s) |
| } |
| for _, sym := range datap { |
| relocsym(ctxt, sym) |
| } |
| for _, s := range dwarfp { |
| relocsym(ctxt, s) |
| } |
| } |
| |
| func dynrelocsym(ctxt *Link, s *Symbol) { |
| if Headtype == objabi.Hwindows && Linkmode != LinkExternal { |
| rel := ctxt.Syms.Lookup(".rel", 0) |
| if s == rel { |
| return |
| } |
| for ri := 0; ri < len(s.R); ri++ { |
| r := &s.R[ri] |
| targ := r.Sym |
| if targ == nil { |
| continue |
| } |
| if !targ.Attr.Reachable() { |
| if r.Type == objabi.R_WEAKADDROFF { |
| continue |
| } |
| Errorf(s, "dynamic relocation to unreachable symbol %s", targ.Name) |
| } |
| if r.Sym.Plt == -2 && r.Sym.Got != -2 { // make dynimport JMP table for PE object files. |
| targ.Plt = int32(rel.Size) |
| r.Sym = rel |
| r.Add = int64(targ.Plt) |
| |
| // jmp *addr |
| if SysArch.Family == sys.I386 { |
| Adduint8(ctxt, rel, 0xff) |
| Adduint8(ctxt, rel, 0x25) |
| Addaddr(ctxt, rel, targ) |
| Adduint8(ctxt, rel, 0x90) |
| Adduint8(ctxt, rel, 0x90) |
| } else { |
| Adduint8(ctxt, rel, 0xff) |
| Adduint8(ctxt, rel, 0x24) |
| Adduint8(ctxt, rel, 0x25) |
| addaddrplus4(ctxt, rel, targ, 0) |
| Adduint8(ctxt, rel, 0x90) |
| } |
| } else if r.Sym.Plt >= 0 { |
| r.Sym = rel |
| r.Add = int64(targ.Plt) |
| } |
| } |
| |
| return |
| } |
| |
| for ri := 0; ri < len(s.R); ri++ { |
| r := &s.R[ri] |
| if Buildmode == BuildmodePIE && Linkmode == LinkInternal { |
| // It's expected that some relocations will be done |
| // later by relocsym (R_TLS_LE, R_ADDROFF), so |
| // don't worry if Adddynrel returns false. |
| Thearch.Adddynrel(ctxt, s, r) |
| continue |
| } |
| if r.Sym != nil && r.Sym.Type == SDYNIMPORT || r.Type >= 256 { |
| if r.Sym != nil && !r.Sym.Attr.Reachable() { |
| Errorf(s, "dynamic relocation to unreachable symbol %s", r.Sym.Name) |
| } |
| if !Thearch.Adddynrel(ctxt, s, r) { |
| Errorf(s, "unsupported dynamic relocation for symbol %s (type=%d stype=%d)", r.Sym.Name, r.Type, r.Sym.Type) |
| } |
| } |
| } |
| } |
| |
| func dynreloc(ctxt *Link, data *[SXREF][]*Symbol) { |
| // -d suppresses dynamic loader format, so we may as well not |
| // compute these sections or mark their symbols as reachable. |
| if *FlagD && Headtype != objabi.Hwindows { |
| return |
| } |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f reloc\n", Cputime()) |
| } |
| |
| for _, s := range ctxt.Textp { |
| dynrelocsym(ctxt, s) |
| } |
| for _, syms := range data { |
| for _, sym := range syms { |
| dynrelocsym(ctxt, sym) |
| } |
| } |
| if Iself { |
| elfdynhash(ctxt) |
| } |
| } |
| |
| func Codeblk(ctxt *Link, addr int64, size int64) { |
| CodeblkPad(ctxt, addr, size, zeros[:]) |
| } |
| func CodeblkPad(ctxt *Link, addr int64, size int64, pad []byte) { |
| if *flagA { |
| ctxt.Logf("codeblk [%#x,%#x) at offset %#x\n", addr, addr+size, coutbuf.Offset()) |
| } |
| |
| blk(ctxt, ctxt.Textp, addr, size, pad) |
| |
| /* again for printing */ |
| if !*flagA { |
| return |
| } |
| |
| syms := ctxt.Textp |
| for i, sym := range syms { |
| if !sym.Attr.Reachable() { |
| continue |
| } |
| if sym.Value >= addr { |
| syms = syms[i:] |
| break |
| } |
| } |
| |
| eaddr := addr + size |
| var q []byte |
| for _, sym := range syms { |
| if !sym.Attr.Reachable() { |
| continue |
| } |
| if sym.Value >= eaddr { |
| break |
| } |
| |
| if addr < sym.Value { |
| ctxt.Logf("%-20s %.8x|", "_", uint64(addr)) |
| for ; addr < sym.Value; addr++ { |
| ctxt.Logf(" %.2x", 0) |
| } |
| ctxt.Logf("\n") |
| } |
| |
| ctxt.Logf("%.6x\t%-20s\n", uint64(addr), sym.Name) |
| q = sym.P |
| |
| for len(q) >= 16 { |
| ctxt.Logf("%.6x\t% x\n", uint64(addr), q[:16]) |
| addr += 16 |
| q = q[16:] |
| } |
| |
| if len(q) > 0 { |
| ctxt.Logf("%.6x\t% x\n", uint64(addr), q) |
| addr += int64(len(q)) |
| } |
| } |
| |
| if addr < eaddr { |
| ctxt.Logf("%-20s %.8x|", "_", uint64(addr)) |
| for ; addr < eaddr; addr++ { |
| ctxt.Logf(" %.2x", 0) |
| } |
| } |
| } |
| |
| func blk(ctxt *Link, syms []*Symbol, addr, size int64, pad []byte) { |
| for i, s := range syms { |
| if s.Type&SSUB == 0 && s.Value >= addr { |
| syms = syms[i:] |
| break |
| } |
| } |
| |
| eaddr := addr + size |
| for _, s := range syms { |
| if s.Type&SSUB != 0 { |
| continue |
| } |
| if s.Value >= eaddr { |
| break |
| } |
| if s.Value < addr { |
| Errorf(s, "phase error: addr=%#x but sym=%#x type=%d", addr, s.Value, s.Type) |
| errorexit() |
| } |
| if addr < s.Value { |
| strnputPad("", int(s.Value-addr), pad) |
| addr = s.Value |
| } |
| Cwrite(s.P) |
| addr += int64(len(s.P)) |
| if addr < s.Value+s.Size { |
| strnputPad("", int(s.Value+s.Size-addr), pad) |
| addr = s.Value + s.Size |
| } |
| if addr != s.Value+s.Size { |
| Errorf(s, "phase error: addr=%#x value+size=%#x", addr, s.Value+s.Size) |
| errorexit() |
| } |
| if s.Value+s.Size >= eaddr { |
| break |
| } |
| } |
| |
| if addr < eaddr { |
| strnputPad("", int(eaddr-addr), pad) |
| } |
| Cflush() |
| } |
| |
| func Datblk(ctxt *Link, addr int64, size int64) { |
| if *flagA { |
| ctxt.Logf("datblk [%#x,%#x) at offset %#x\n", addr, addr+size, coutbuf.Offset()) |
| } |
| |
| blk(ctxt, datap, addr, size, zeros[:]) |
| |
| /* again for printing */ |
| if !*flagA { |
| return |
| } |
| |
| syms := datap |
| for i, sym := range syms { |
| if sym.Value >= addr { |
| syms = syms[i:] |
| break |
| } |
| } |
| |
| eaddr := addr + size |
| for _, sym := range syms { |
| if sym.Value >= eaddr { |
| break |
| } |
| if addr < sym.Value { |
| ctxt.Logf("\t%.8x| 00 ...\n", uint64(addr)) |
| addr = sym.Value |
| } |
| |
| ctxt.Logf("%s\n\t%.8x|", sym.Name, uint64(addr)) |
| for i, b := range sym.P { |
| if i > 0 && i%16 == 0 { |
| ctxt.Logf("\n\t%.8x|", uint64(addr)+uint64(i)) |
| } |
| ctxt.Logf(" %.2x", b) |
| } |
| |
| addr += int64(len(sym.P)) |
| for ; addr < sym.Value+sym.Size; addr++ { |
| ctxt.Logf(" %.2x", 0) |
| } |
| ctxt.Logf("\n") |
| |
| if Linkmode != LinkExternal { |
| continue |
| } |
| for _, r := range sym.R { |
| rsname := "" |
| if r.Sym != nil { |
| rsname = r.Sym.Name |
| } |
| typ := "?" |
| switch r.Type { |
| case objabi.R_ADDR: |
| typ = "addr" |
| case objabi.R_PCREL: |
| typ = "pcrel" |
| case objabi.R_CALL: |
| typ = "call" |
| } |
| ctxt.Logf("\treloc %.8x/%d %s %s+%#x [%#x]\n", uint(sym.Value+int64(r.Off)), r.Siz, typ, rsname, r.Add, r.Sym.Value+r.Add) |
| } |
| } |
| |
| if addr < eaddr { |
| ctxt.Logf("\t%.8x| 00 ...\n", uint(addr)) |
| } |
| ctxt.Logf("\t%.8x|\n", uint(eaddr)) |
| } |
| |
| func Dwarfblk(ctxt *Link, addr int64, size int64) { |
| if *flagA { |
| ctxt.Logf("dwarfblk [%#x,%#x) at offset %#x\n", addr, addr+size, coutbuf.Offset()) |
| } |
| |
| blk(ctxt, dwarfp, addr, size, zeros[:]) |
| } |
| |
| var zeros [512]byte |
| |
| // strnput writes the first n bytes of s. |
| // If n is larger than len(s), |
| // it is padded with NUL bytes. |
| func strnput(s string, n int) { |
| strnputPad(s, n, zeros[:]) |
| } |
| |
| // strnput writes the first n bytes of s. |
| // If n is larger than len(s), |
| // it is padded with the bytes in pad (repeated as needed). |
| func strnputPad(s string, n int, pad []byte) { |
| if len(s) >= n { |
| Cwritestring(s[:n]) |
| } else { |
| Cwritestring(s) |
| n -= len(s) |
| for n > len(pad) { |
| Cwrite(pad) |
| n -= len(pad) |
| |
| } |
| Cwrite(pad[:n]) |
| } |
| } |
| |
| var strdata []*Symbol |
| |
| func addstrdata1(ctxt *Link, arg string) { |
| eq := strings.Index(arg, "=") |
| dot := strings.LastIndex(arg[:eq+1], ".") |
| if eq < 0 || dot < 0 { |
| Exitf("-X flag requires argument of the form importpath.name=value") |
| } |
| addstrdata(ctxt, objabi.PathToPrefix(arg[:dot])+arg[dot:eq], arg[eq+1:]) |
| } |
| |
| func addstrdata(ctxt *Link, name string, value string) { |
| p := fmt.Sprintf("%s.str", name) |
| sp := ctxt.Syms.Lookup(p, 0) |
| |
| Addstring(sp, value) |
| sp.Type = SRODATA |
| |
| s := ctxt.Syms.Lookup(name, 0) |
| s.Size = 0 |
| s.Attr |= AttrDuplicateOK |
| reachable := s.Attr.Reachable() |
| Addaddr(ctxt, s, sp) |
| adduintxx(ctxt, s, uint64(len(value)), SysArch.PtrSize) |
| |
| // addstring, addaddr, etc., mark the symbols as reachable. |
| // In this case that is not necessarily true, so stick to what |
| // we know before entering this function. |
| s.Attr.Set(AttrReachable, reachable) |
| |
| strdata = append(strdata, s) |
| |
| sp.Attr.Set(AttrReachable, reachable) |
| } |
| |
| func (ctxt *Link) checkstrdata() { |
| for _, s := range strdata { |
| if s.Type == STEXT { |
| Errorf(s, "cannot use -X with text symbol") |
| } else if s.Gotype != nil && s.Gotype.Name != "type.string" { |
| Errorf(s, "cannot use -X with non-string symbol") |
| } |
| } |
| } |
| |
| func Addstring(s *Symbol, str string) int64 { |
| if s.Type == 0 { |
| s.Type = SNOPTRDATA |
| } |
| s.Attr |= AttrReachable |
| r := s.Size |
| if s.Name == ".shstrtab" { |
| elfsetstring(s, str, int(r)) |
| } |
| s.P = append(s.P, str...) |
| s.P = append(s.P, 0) |
| s.Size = int64(len(s.P)) |
| return r |
| } |
| |
| // addgostring adds str, as a Go string value, to s. symname is the name of the |
| // symbol used to define the string data and must be unique per linked object. |
| func addgostring(ctxt *Link, s *Symbol, symname, str string) { |
| sym := ctxt.Syms.Lookup(symname, 0) |
| if sym.Type != Sxxx { |
| Errorf(s, "duplicate symname in addgostring: %s", symname) |
| } |
| sym.Attr |= AttrReachable |
| sym.Attr |= AttrLocal |
| sym.Type = SRODATA |
| sym.Size = int64(len(str)) |
| sym.P = []byte(str) |
| Addaddr(ctxt, s, sym) |
| adduint(ctxt, s, uint64(len(str))) |
| } |
| |
| func addinitarrdata(ctxt *Link, s *Symbol) { |
| p := s.Name + ".ptr" |
| sp := ctxt.Syms.Lookup(p, 0) |
| sp.Type = SINITARR |
| sp.Size = 0 |
| sp.Attr |= AttrDuplicateOK |
| Addaddr(ctxt, sp, s) |
| } |
| |
| func dosymtype(ctxt *Link) { |
| switch Buildmode { |
| case BuildmodeCArchive, BuildmodeCShared: |
| for _, s := range ctxt.Syms.Allsym { |
| // Create a new entry in the .init_array section that points to the |
| // library initializer function. |
| switch Buildmode { |
| case BuildmodeCArchive, BuildmodeCShared: |
| if s.Name == *flagEntrySymbol { |
| addinitarrdata(ctxt, s) |
| } |
| } |
| } |
| } |
| } |
| |
| // symalign returns the required alignment for the given symbol s. |
| func symalign(s *Symbol) int32 { |
| min := int32(Thearch.Minalign) |
| if s.Align >= min { |
| return s.Align |
| } else if s.Align != 0 { |
| return min |
| } |
| if strings.HasPrefix(s.Name, "go.string.") || strings.HasPrefix(s.Name, "type..namedata.") { |
| // String data is just bytes. |
| // If we align it, we waste a lot of space to padding. |
| return min |
| } |
| align := int32(Thearch.Maxalign) |
| for int64(align) > s.Size && align > min { |
| align >>= 1 |
| } |
| return align |
| } |
| |
| func aligndatsize(datsize int64, s *Symbol) int64 { |
| return Rnd(datsize, int64(symalign(s))) |
| } |
| |
| const debugGCProg = false |
| |
| type GCProg struct { |
| ctxt *Link |
| sym *Symbol |
| w gcprog.Writer |
| } |
| |
| func (p *GCProg) Init(ctxt *Link, name string) { |
| p.ctxt = ctxt |
| p.sym = ctxt.Syms.Lookup(name, 0) |
| p.w.Init(p.writeByte(ctxt)) |
| if debugGCProg { |
| fmt.Fprintf(os.Stderr, "ld: start GCProg %s\n", name) |
| p.w.Debug(os.Stderr) |
| } |
| } |
| |
| func (p *GCProg) writeByte(ctxt *Link) func(x byte) { |
| return func(x byte) { |
| Adduint8(ctxt, p.sym, x) |
| } |
| } |
| |
| func (p *GCProg) End(size int64) { |
| p.w.ZeroUntil(size / int64(SysArch.PtrSize)) |
| p.w.End() |
| if debugGCProg { |
| fmt.Fprintf(os.Stderr, "ld: end GCProg\n") |
| } |
| } |
| |
| func (p *GCProg) AddSym(s *Symbol) { |
| typ := s.Gotype |
| // Things without pointers should be in SNOPTRDATA or SNOPTRBSS; |
| // everything we see should have pointers and should therefore have a type. |
| if typ == nil { |
| switch s.Name { |
| case "runtime.data", "runtime.edata", "runtime.bss", "runtime.ebss": |
| // Ignore special symbols that are sometimes laid out |
| // as real symbols. See comment about dyld on darwin in |
| // the address function. |
| return |
| } |
| Errorf(s, "missing Go type information for global symbol: size %d", s.Size) |
| return |
| } |
| |
| ptrsize := int64(SysArch.PtrSize) |
| nptr := decodetypePtrdata(p.ctxt.Arch, typ) / ptrsize |
| |
| if debugGCProg { |
| fmt.Fprintf(os.Stderr, "gcprog sym: %s at %d (ptr=%d+%d)\n", s.Name, s.Value, s.Value/ptrsize, nptr) |
| } |
| |
| if decodetypeUsegcprog(typ) == 0 { |
| // Copy pointers from mask into program. |
| mask := decodetypeGcmask(p.ctxt, typ) |
| for i := int64(0); i < nptr; i++ { |
| if (mask[i/8]>>uint(i%8))&1 != 0 { |
| p.w.Ptr(s.Value/ptrsize + i) |
| } |
| } |
| return |
| } |
| |
| // Copy program. |
| prog := decodetypeGcprog(p.ctxt, typ) |
| p.w.ZeroUntil(s.Value / ptrsize) |
| p.w.Append(prog[4:], nptr) |
| } |
| |
| // dataSortKey is used to sort a slice of data symbol *Symbol pointers. |
| // The sort keys are kept inline to improve cache behavior while sorting. |
| type dataSortKey struct { |
| size int64 |
| name string |
| sym *Symbol |
| } |
| |
| type bySizeAndName []dataSortKey |
| |
| func (d bySizeAndName) Len() int { return len(d) } |
| func (d bySizeAndName) Swap(i, j int) { d[i], d[j] = d[j], d[i] } |
| func (d bySizeAndName) Less(i, j int) bool { |
| s1, s2 := d[i], d[j] |
| if s1.size != s2.size { |
| return s1.size < s2.size |
| } |
| return s1.name < s2.name |
| } |
| |
| const cutoff int64 = 2e9 // 2 GB (or so; looks better in errors than 2^31) |
| |
| func checkdatsize(ctxt *Link, datsize int64, symn SymKind) { |
| if datsize > cutoff { |
| Errorf(nil, "too much data in section %v (over %d bytes)", symn, cutoff) |
| } |
| } |
| |
| // datap is a collection of reachable data symbols in address order. |
| // Generated by dodata. |
| var datap []*Symbol |
| |
| func (ctxt *Link) dodata() { |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f dodata\n", Cputime()) |
| } |
| |
| if ctxt.DynlinkingGo() && Headtype == objabi.Hdarwin { |
| // The values in moduledata are filled out by relocations |
| // pointing to the addresses of these special symbols. |
| // Typically these symbols have no size and are not laid |
| // out with their matching section. |
| // |
| // However on darwin, dyld will find the special symbol |
| // in the first loaded module, even though it is local. |
| // |
| // (An hypothesis, formed without looking in the dyld sources: |
| // these special symbols have no size, so their address |
| // matches a real symbol. The dynamic linker assumes we |
| // want the normal symbol with the same address and finds |
| // it in the other module.) |
| // |
| // To work around this we lay out the symbls whose |
| // addresses are vital for multi-module programs to work |
| // as normal symbols, and give them a little size. |
| bss := ctxt.Syms.Lookup("runtime.bss", 0) |
| bss.Size = 8 |
| bss.Attr.Set(AttrSpecial, false) |
| |
| ctxt.Syms.Lookup("runtime.ebss", 0).Attr.Set(AttrSpecial, false) |
| |
| data := ctxt.Syms.Lookup("runtime.data", 0) |
| data.Size = 8 |
| data.Attr.Set(AttrSpecial, false) |
| |
| ctxt.Syms.Lookup("runtime.edata", 0).Attr.Set(AttrSpecial, false) |
| |
| types := ctxt.Syms.Lookup("runtime.types", 0) |
| types.Type = STYPE |
| types.Size = 8 |
| types.Attr.Set(AttrSpecial, false) |
| |
| etypes := ctxt.Syms.Lookup("runtime.etypes", 0) |
| etypes.Type = SFUNCTAB |
| etypes.Attr.Set(AttrSpecial, false) |
| } |
| |
| // Collect data symbols by type into data. |
| var data [SXREF][]*Symbol |
| for _, s := range ctxt.Syms.Allsym { |
| if !s.Attr.Reachable() || s.Attr.Special() { |
| continue |
| } |
| if s.Type <= STEXT || s.Type >= SXREF { |
| continue |
| } |
| data[s.Type] = append(data[s.Type], s) |
| } |
| |
| // Now that we have the data symbols, but before we start |
| // to assign addresses, record all the necessary |
| // dynamic relocations. These will grow the relocation |
| // symbol, which is itself data. |
| // |
| // On darwin, we need the symbol table numbers for dynreloc. |
| if Headtype == objabi.Hdarwin { |
| machosymorder(ctxt) |
| } |
| dynreloc(ctxt, &data) |
| |
| if UseRelro() { |
| // "read only" data with relocations needs to go in its own section |
| // when building a shared library. We do this by boosting objects of |
| // type SXXX with relocations to type SXXXRELRO. |
| for _, symnro := range readOnly { |
| symnrelro := relROMap[symnro] |
| |
| ro := []*Symbol{} |
| relro := data[symnrelro] |
| |
| for _, s := range data[symnro] { |
| isRelro := len(s.R) > 0 |
| switch s.Type { |
| case STYPE, STYPERELRO, SGOFUNCRELRO: |
| // Symbols are not sorted yet, so it is possible |
| // that an Outer symbol has been changed to a |
| // relro Type before it reaches here. |
| isRelro = true |
| } |
| if isRelro { |
| s.Type = symnrelro |
| if s.Outer != nil { |
| s.Outer.Type = s.Type |
| } |
| relro = append(relro, s) |
| } else { |
| ro = append(ro, s) |
| } |
| } |
| |
| // Check that we haven't made two symbols with the same .Outer into |
| // different types (because references two symbols with non-nil Outer |
| // become references to the outer symbol + offset it's vital that the |
| // symbol and the outer end up in the same section). |
| for _, s := range relro { |
| if s.Outer != nil && s.Outer.Type != s.Type { |
| Errorf(s, "inconsistent types for symbol and its Outer %s (%v != %v)", |
| s.Outer.Name, s.Type, s.Outer.Type) |
| } |
| } |
| |
| data[symnro] = ro |
| data[symnrelro] = relro |
| } |
| } |
| |
| // Sort symbols. |
| var dataMaxAlign [SXREF]int32 |
| var wg sync.WaitGroup |
| for symn := range data { |
| symn := SymKind(symn) |
| wg.Add(1) |
| go func() { |
| data[symn], dataMaxAlign[symn] = dodataSect(ctxt, symn, data[symn]) |
| wg.Done() |
| }() |
| } |
| wg.Wait() |
| |
| // Allocate sections. |
| // Data is processed before segtext, because we need |
| // to see all symbols in the .data and .bss sections in order |
| // to generate garbage collection information. |
| datsize := int64(0) |
| |
| // Writable data sections that do not need any specialized handling. |
| writable := []SymKind{ |
| SELFSECT, |
| SMACHO, |
| SMACHOGOT, |
| SWINDOWS, |
| } |
| for _, symn := range writable { |
| for _, s := range data[symn] { |
| sect := addsection(&Segdata, s.Name, 06) |
| sect.Align = symalign(s) |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| s.Sect = sect |
| s.Type = SDATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| sect.Length = uint64(datsize) - sect.Vaddr |
| } |
| checkdatsize(ctxt, datsize, symn) |
| } |
| |
| // .got (and .toc on ppc64) |
| if len(data[SELFGOT]) > 0 { |
| sect := addsection(&Segdata, ".got", 06) |
| sect.Align = dataMaxAlign[SELFGOT] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| var toc *Symbol |
| for _, s := range data[SELFGOT] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Type = SDATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| |
| // Resolve .TOC. symbol for this object file (ppc64) |
| toc = ctxt.Syms.ROLookup(".TOC.", int(s.Version)) |
| if toc != nil { |
| toc.Sect = sect |
| toc.Outer = s |
| toc.Sub = s.Sub |
| s.Sub = toc |
| |
| toc.Value = 0x8000 |
| } |
| |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, SELFGOT) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| } |
| |
| /* pointer-free data */ |
| sect := addsection(&Segdata, ".noptrdata", 06) |
| sect.Align = dataMaxAlign[SNOPTRDATA] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| ctxt.Syms.Lookup("runtime.noptrdata", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.enoptrdata", 0).Sect = sect |
| for _, s := range data[SNOPTRDATA] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Type = SDATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, SNOPTRDATA) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| |
| hasinitarr := *FlagLinkshared |
| |
| /* shared library initializer */ |
| switch Buildmode { |
| case BuildmodeCArchive, BuildmodeCShared, BuildmodeShared, BuildmodePlugin: |
| hasinitarr = true |
| } |
| if hasinitarr { |
| sect := addsection(&Segdata, ".init_array", 06) |
| sect.Align = dataMaxAlign[SINITARR] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| for _, s := range data[SINITARR] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| sect.Length = uint64(datsize) - sect.Vaddr |
| checkdatsize(ctxt, datsize, SINITARR) |
| } |
| |
| /* data */ |
| sect = addsection(&Segdata, ".data", 06) |
| sect.Align = dataMaxAlign[SDATA] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| ctxt.Syms.Lookup("runtime.data", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.edata", 0).Sect = sect |
| var gc GCProg |
| gc.Init(ctxt, "runtime.gcdata") |
| for _, s := range data[SDATA] { |
| s.Sect = sect |
| s.Type = SDATA |
| datsize = aligndatsize(datsize, s) |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| gc.AddSym(s) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, SDATA) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| gc.End(int64(sect.Length)) |
| |
| /* bss */ |
| sect = addsection(&Segdata, ".bss", 06) |
| sect.Align = dataMaxAlign[SBSS] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| ctxt.Syms.Lookup("runtime.bss", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.ebss", 0).Sect = sect |
| gc = GCProg{} |
| gc.Init(ctxt, "runtime.gcbss") |
| for _, s := range data[SBSS] { |
| s.Sect = sect |
| datsize = aligndatsize(datsize, s) |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| gc.AddSym(s) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, SBSS) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| gc.End(int64(sect.Length)) |
| |
| /* pointer-free bss */ |
| sect = addsection(&Segdata, ".noptrbss", 06) |
| sect.Align = dataMaxAlign[SNOPTRBSS] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| ctxt.Syms.Lookup("runtime.noptrbss", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.enoptrbss", 0).Sect = sect |
| for _, s := range data[SNOPTRBSS] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| |
| sect.Length = uint64(datsize) - sect.Vaddr |
| ctxt.Syms.Lookup("runtime.end", 0).Sect = sect |
| checkdatsize(ctxt, datsize, SNOPTRBSS) |
| |
| if len(data[STLSBSS]) > 0 { |
| var sect *Section |
| if Iself && (Linkmode == LinkExternal || !*FlagD) { |
| sect = addsection(&Segdata, ".tbss", 06) |
| sect.Align = int32(SysArch.PtrSize) |
| sect.Vaddr = 0 |
| } |
| datsize = 0 |
| |
| for _, s := range data[STLSBSS] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Value = datsize |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, STLSBSS) |
| |
| if sect != nil { |
| sect.Length = uint64(datsize) |
| } |
| } |
| |
| /* |
| * We finished data, begin read-only data. |
| * Not all systems support a separate read-only non-executable data section. |
| * ELF systems do. |
| * OS X and Plan 9 do not. |
| * Windows PE may, but if so we have not implemented it. |
| * And if we're using external linking mode, the point is moot, |
| * since it's not our decision; that code expects the sections in |
| * segtext. |
| */ |
| var segro *Segment |
| if Iself && Linkmode == LinkInternal { |
| segro = &Segrodata |
| } else { |
| segro = &Segtext |
| } |
| |
| datsize = 0 |
| |
| /* read-only executable ELF, Mach-O sections */ |
| if len(data[STEXT]) != 0 { |
| Errorf(nil, "dodata found an STEXT symbol: %s", data[STEXT][0].Name) |
| } |
| for _, s := range data[SELFRXSECT] { |
| sect := addsection(&Segtext, s.Name, 04) |
| sect.Align = symalign(s) |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| sect.Length = uint64(datsize) - sect.Vaddr |
| checkdatsize(ctxt, datsize, SELFRXSECT) |
| } |
| |
| /* read-only data */ |
| sect = addsection(segro, ".rodata", 04) |
| |
| sect.Vaddr = 0 |
| ctxt.Syms.Lookup("runtime.rodata", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.erodata", 0).Sect = sect |
| if !UseRelro() { |
| ctxt.Syms.Lookup("runtime.types", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.etypes", 0).Sect = sect |
| } |
| for _, symn := range readOnly { |
| align := dataMaxAlign[symn] |
| if sect.Align < align { |
| sect.Align = align |
| } |
| } |
| datsize = Rnd(datsize, int64(sect.Align)) |
| for _, symn := range readOnly { |
| for _, s := range data[symn] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, symn) |
| } |
| sect.Length = uint64(datsize) - sect.Vaddr |
| |
| /* read-only ELF, Mach-O sections */ |
| for _, s := range data[SELFROSECT] { |
| sect = addsection(segro, s.Name, 04) |
| sect.Align = symalign(s) |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| sect.Length = uint64(datsize) - sect.Vaddr |
| } |
| checkdatsize(ctxt, datsize, SELFROSECT) |
| |
| for _, s := range data[SMACHOPLT] { |
| sect = addsection(segro, s.Name, 04) |
| sect.Align = symalign(s) |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| sect.Length = uint64(datsize) - sect.Vaddr |
| } |
| checkdatsize(ctxt, datsize, SMACHOPLT) |
| |
| // There is some data that are conceptually read-only but are written to by |
| // relocations. On GNU systems, we can arrange for the dynamic linker to |
| // mprotect sections after relocations are applied by giving them write |
| // permissions in the object file and calling them ".data.rel.ro.FOO". We |
| // divide the .rodata section between actual .rodata and .data.rel.ro.rodata, |
| // but for the other sections that this applies to, we just write a read-only |
| // .FOO section or a read-write .data.rel.ro.FOO section depending on the |
| // situation. |
| // TODO(mwhudson): It would make sense to do this more widely, but it makes |
| // the system linker segfault on darwin. |
| addrelrosection := func(suffix string) *Section { |
| return addsection(segro, suffix, 04) |
| } |
| |
| if UseRelro() { |
| addrelrosection = func(suffix string) *Section { |
| seg := &Segrelrodata |
| if Linkmode == LinkExternal { |
| // Using a separate segment with an external |
| // linker results in some programs moving |
| // their data sections unexpectedly, which |
| // corrupts the moduledata. So we use the |
| // rodata segment and let the external linker |
| // sort out a rel.ro segment. |
| seg = &Segrodata |
| } |
| return addsection(seg, ".data.rel.ro"+suffix, 06) |
| } |
| /* data only written by relocations */ |
| sect = addrelrosection("") |
| |
| sect.Vaddr = 0 |
| ctxt.Syms.Lookup("runtime.types", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.etypes", 0).Sect = sect |
| for _, symnro := range readOnly { |
| symn := relROMap[symnro] |
| align := dataMaxAlign[symn] |
| if sect.Align < align { |
| sect.Align = align |
| } |
| } |
| datsize = Rnd(datsize, int64(sect.Align)) |
| for _, symnro := range readOnly { |
| symn := relROMap[symnro] |
| for _, s := range data[symn] { |
| datsize = aligndatsize(datsize, s) |
| if s.Outer != nil && s.Outer.Sect != nil && s.Outer.Sect != sect { |
| Errorf(s, "s.Outer (%s) in different section from s, %s != %s", s.Outer.Name, s.Outer.Sect.Name, sect.Name) |
| } |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, symn) |
| } |
| |
| sect.Length = uint64(datsize) - sect.Vaddr |
| } |
| |
| /* typelink */ |
| sect = addrelrosection(".typelink") |
| sect.Align = dataMaxAlign[STYPELINK] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| typelink := ctxt.Syms.Lookup("runtime.typelink", 0) |
| typelink.Sect = sect |
| typelink.Type = SRODATA |
| datsize += typelink.Size |
| checkdatsize(ctxt, datsize, STYPELINK) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| |
| /* itablink */ |
| sect = addrelrosection(".itablink") |
| sect.Align = dataMaxAlign[SITABLINK] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| ctxt.Syms.Lookup("runtime.itablink", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.eitablink", 0).Sect = sect |
| for _, s := range data[SITABLINK] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, SITABLINK) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| |
| /* gosymtab */ |
| sect = addrelrosection(".gosymtab") |
| sect.Align = dataMaxAlign[SSYMTAB] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| ctxt.Syms.Lookup("runtime.symtab", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.esymtab", 0).Sect = sect |
| for _, s := range data[SSYMTAB] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, SSYMTAB) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| |
| /* gopclntab */ |
| sect = addrelrosection(".gopclntab") |
| sect.Align = dataMaxAlign[SPCLNTAB] |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| ctxt.Syms.Lookup("runtime.pclntab", 0).Sect = sect |
| ctxt.Syms.Lookup("runtime.epclntab", 0).Sect = sect |
| for _, s := range data[SPCLNTAB] { |
| datsize = aligndatsize(datsize, s) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| } |
| checkdatsize(ctxt, datsize, SRODATA) |
| sect.Length = uint64(datsize) - sect.Vaddr |
| |
| // 6g uses 4-byte relocation offsets, so the entire segment must fit in 32 bits. |
| if datsize != int64(uint32(datsize)) { |
| Errorf(nil, "read-only data segment too large: %d", datsize) |
| } |
| |
| for symn := SELFRXSECT; symn < SXREF; symn++ { |
| datap = append(datap, data[symn]...) |
| } |
| |
| dwarfgeneratedebugsyms(ctxt) |
| |
| var s *Symbol |
| var i int |
| for i, s = range dwarfp { |
| if s.Type != SDWARFSECT { |
| break |
| } |
| |
| sect = addsection(&Segdwarf, s.Name, 04) |
| sect.Align = 1 |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| datsize += s.Size |
| sect.Length = uint64(datsize) - sect.Vaddr |
| } |
| checkdatsize(ctxt, datsize, SDWARFSECT) |
| |
| if i < len(dwarfp) { |
| sect = addsection(&Segdwarf, ".debug_info", 04) |
| sect.Align = 1 |
| datsize = Rnd(datsize, int64(sect.Align)) |
| sect.Vaddr = uint64(datsize) |
| for _, s := range dwarfp[i:] { |
| if s.Type != SDWARFINFO { |
| break |
| } |
| s.Sect = sect |
| s.Type = SRODATA |
| s.Value = int64(uint64(datsize) - sect.Vaddr) |
| s.Attr |= AttrLocal |
| datsize += s.Size |
| } |
| sect.Length = uint64(datsize) - sect.Vaddr |
| checkdatsize(ctxt, datsize, SDWARFINFO) |
| } |
| |
| /* number the sections */ |
| n := int32(1) |
| |
| for _, sect := range Segtext.Sections { |
| sect.Extnum = int16(n) |
| n++ |
| } |
| for _, sect := range Segrodata.Sections { |
| sect.Extnum = int16(n) |
| n++ |
| } |
| for _, sect := range Segrelrodata.Sections { |
| sect.Extnum = int16(n) |
| n++ |
| } |
| for _, sect := range Segdata.Sections { |
| sect.Extnum = int16(n) |
| n++ |
| } |
| for _, sect := range Segdwarf.Sections { |
| sect.Extnum = int16(n) |
| n++ |
| } |
| } |
| |
| func dodataSect(ctxt *Link, symn SymKind, syms []*Symbol) (result []*Symbol, maxAlign int32) { |
| if Headtype == objabi.Hdarwin { |
| // Some symbols may no longer belong in syms |
| // due to movement in machosymorder. |
| newSyms := make([]*Symbol, 0, len(syms)) |
| for _, s := range syms { |
| if s.Type == symn { |
| newSyms = append(newSyms, s) |
| } |
| } |
| syms = newSyms |
| } |
| |
| var head, tail *Symbol |
| symsSort := make([]dataSortKey, 0, len(syms)) |
| for _, s := range syms { |
| if s.Attr.OnList() { |
| log.Fatalf("symbol %s listed multiple times", s.Name) |
| } |
| s.Attr |= AttrOnList |
| switch { |
| case s.Size < int64(len(s.P)): |
| Errorf(s, "initialize bounds (%d < %d)", s.Size, len(s.P)) |
| case s.Size < 0: |
| Errorf(s, "negative size (%d bytes)", s.Size) |
| case s.Size > cutoff: |
| Errorf(s, "symbol too large (%d bytes)", s.Size) |
| } |
| |
| // If the usually-special section-marker symbols are being laid |
| // out as regular symbols, put them either at the beginning or |
| // end of their section. |
| if ctxt.DynlinkingGo() && Headtype == objabi.Hdarwin { |
| switch s.Name { |
| case "runtime.text", "runtime.bss", "runtime.data", "runtime.types": |
| head = s |
| continue |
| case "runtime.etext", "runtime.ebss", "runtime.edata", "runtime.etypes": |
| tail = s |
| continue |
| } |
| } |
| |
| key := dataSortKey{ |
| size: s.Size, |
| name: s.Name, |
| sym: s, |
| } |
| |
| switch s.Type { |
| case SELFGOT: |
| // For ppc64, we want to interleave the .got and .toc sections |
| // from input files. Both are type SELFGOT, so in that case |
| // we skip size comparison and fall through to the name |
| // comparison (conveniently, .got sorts before .toc). |
| key.size = 0 |
| } |
| |
| symsSort = append(symsSort, key) |
| } |
| |
| sort.Sort(bySizeAndName(symsSort)) |
| |
| off := 0 |
| if head != nil { |
| syms[0] = head |
| off++ |
| } |
| for i, symSort := range symsSort { |
| syms[i+off] = symSort.sym |
| align := symalign(symSort.sym) |
| if maxAlign < align { |
| maxAlign = align |
| } |
| } |
| if tail != nil { |
| syms[len(syms)-1] = tail |
| } |
| |
| if Iself && symn == SELFROSECT { |
| // Make .rela and .rela.plt contiguous, the ELF ABI requires this |
| // and Solaris actually cares. |
| reli, plti := -1, -1 |
| for i, s := range syms { |
| switch s.Name { |
| case ".rel.plt", ".rela.plt": |
| plti = i |
| case ".rel", ".rela": |
| reli = i |
| } |
| } |
| if reli >= 0 && plti >= 0 && plti != reli+1 { |
| var first, second int |
| if plti > reli { |
| first, second = reli, plti |
| } else { |
| first, second = plti, reli |
| } |
| rel, plt := syms[reli], syms[plti] |
| copy(syms[first+2:], syms[first+1:second]) |
| syms[first+0] = rel |
| syms[first+1] = plt |
| |
| // Make sure alignment doesn't introduce a gap. |
| // Setting the alignment explicitly prevents |
| // symalign from basing it on the size and |
| // getting it wrong. |
| rel.Align = int32(SysArch.RegSize) |
| plt.Align = int32(SysArch.RegSize) |
| } |
| } |
| |
| return syms, maxAlign |
| } |
| |
| // Add buildid to beginning of text segment, on non-ELF systems. |
| // Non-ELF binary formats are not always flexible enough to |
| // give us a place to put the Go build ID. On those systems, we put it |
| // at the very beginning of the text segment. |
| // This ``header'' is read by cmd/go. |
| func (ctxt *Link) textbuildid() { |
| if Iself || Buildmode == BuildmodePlugin || *flagBuildid == "" { |
| return |
| } |
| |
| sym := ctxt.Syms.Lookup("go.buildid", 0) |
| sym.Attr |= AttrReachable |
| // The \xff is invalid UTF-8, meant to make it less likely |
| // to find one of these accidentally. |
| data := "\xff Go build ID: " + strconv.Quote(*flagBuildid) + "\n \xff" |
| sym.Type = STEXT |
| sym.P = []byte(data) |
| sym.Size = int64(len(sym.P)) |
| |
| ctxt.Textp = append(ctxt.Textp, nil) |
| copy(ctxt.Textp[1:], ctxt.Textp) |
| ctxt.Textp[0] = sym |
| } |
| |
| // assign addresses to text |
| func (ctxt *Link) textaddress() { |
| addsection(&Segtext, ".text", 05) |
| |
| // Assign PCs in text segment. |
| // Could parallelize, by assigning to text |
| // and then letting threads copy down, but probably not worth it. |
| sect := Segtext.Sections[0] |
| |
| sect.Align = int32(Funcalign) |
| |
| text := ctxt.Syms.Lookup("runtime.text", 0) |
| text.Sect = sect |
| |
| if ctxt.DynlinkingGo() && Headtype == objabi.Hdarwin { |
| etext := ctxt.Syms.Lookup("runtime.etext", 0) |
| etext.Sect = sect |
| |
| ctxt.Textp = append(ctxt.Textp, etext, nil) |
| copy(ctxt.Textp[1:], ctxt.Textp) |
| ctxt.Textp[0] = text |
| } |
| |
| va := uint64(*FlagTextAddr) |
| n := 1 |
| sect.Vaddr = va |
| ntramps := 0 |
| for _, sym := range ctxt.Textp { |
| sect, n, va = assignAddress(ctxt, sect, n, sym, va, false) |
| |
| trampoline(ctxt, sym) // resolve jumps, may add trampolines if jump too far |
| |
| // lay down trampolines after each function |
| for ; ntramps < len(ctxt.tramps); ntramps++ { |
| tramp := ctxt.tramps[ntramps] |
| sect, n, va = assignAddress(ctxt, sect, n, tramp, va, true) |
| } |
| } |
| |
| sect.Length = va - sect.Vaddr |
| ctxt.Syms.Lookup("runtime.etext", 0).Sect = sect |
| |
| // merge tramps into Textp, keeping Textp in address order |
| if ntramps != 0 { |
| newtextp := make([]*Symbol, 0, len(ctxt.Textp)+ntramps) |
| i := 0 |
| for _, sym := range ctxt.Textp { |
| for ; i < ntramps && ctxt.tramps[i].Value < sym.Value; i++ { |
| newtextp = append(newtextp, ctxt.tramps[i]) |
| } |
| newtextp = append(newtextp, sym) |
| } |
| newtextp = append(newtextp, ctxt.tramps[i:ntramps]...) |
| |
| ctxt.Textp = newtextp |
| } |
| } |
| |
| // assigns address for a text symbol, returns (possibly new) section, its number, and the address |
| // Note: once we have trampoline insertion support for external linking, this function |
| // will not need to create new text sections, and so no need to return sect and n. |
| func assignAddress(ctxt *Link, sect *Section, n int, sym *Symbol, va uint64, isTramp bool) (*Section, int, uint64) { |
| sym.Sect = sect |
| if sym.Type&SSUB != 0 { |
| return sect, n, va |
| } |
| if sym.Align != 0 { |
| va = uint64(Rnd(int64(va), int64(sym.Align))) |
| } else { |
| va = uint64(Rnd(int64(va), int64(Funcalign))) |
| } |
| sym.Value = 0 |
| for sub := sym; sub != nil; sub = sub.Sub { |
| sub.Value += int64(va) |
| } |
| |
| funcsize := uint64(MINFUNC) // spacing required for findfunctab |
| if sym.Size > MINFUNC { |
| funcsize = uint64(sym.Size) |
| } |
| |
| // On ppc64x a text section should not be larger than 2^26 bytes due to the size of |
| // call target offset field in the bl instruction. Splitting into smaller text |
| // sections smaller than this limit allows the GNU linker to modify the long calls |
| // appropriately. The limit allows for the space needed for tables inserted by the linker. |
| |
| // If this function doesn't fit in the current text section, then create a new one. |
| |
| // Only break at outermost syms. |
| |
| if SysArch.InFamily(sys.PPC64) && sym.Outer == nil && Iself && Linkmode == LinkExternal && va-sect.Vaddr+funcsize+maxSizeTrampolinesPPC64(sym, isTramp) > 0x1c00000 { |
| |
| // Set the length for the previous text section |
| sect.Length = va - sect.Vaddr |
| |
| // Create new section, set the starting Vaddr |
| sect = addsection(&Segtext, ".text", 05) |
| sect.Vaddr = va |
| sym.Sect = sect |
| |
| // Create a symbol for the start of the secondary text sections |
| ctxt.Syms.Lookup(fmt.Sprintf("runtime.text.%d", n), 0).Sect = sect |
| n++ |
| } |
| va += funcsize |
| |
| return sect, n, va |
| } |
| |
| // assign addresses |
| func (ctxt *Link) address() { |
| va := uint64(*FlagTextAddr) |
| Segtext.Rwx = 05 |
| Segtext.Vaddr = va |
| Segtext.Fileoff = uint64(HEADR) |
| for _, s := range Segtext.Sections { |
| va = uint64(Rnd(int64(va), int64(s.Align))) |
| s.Vaddr = va |
| va += s.Length |
| } |
| |
| Segtext.Length = va - uint64(*FlagTextAddr) |
| Segtext.Filelen = Segtext.Length |
| if Headtype == objabi.Hnacl { |
| va += 32 // room for the "halt sled" |
| } |
| |
| if len(Segrodata.Sections) > 0 { |
| // align to page boundary so as not to mix |
| // rodata and executable text. |
| // |
| // Note: gold or GNU ld will reduce the size of the executable |
| // file by arranging for the relro segment to end at a page |
| // boundary, and overlap the end of the text segment with the |
| // start of the relro segment in the file. The PT_LOAD segments |
| // will be such that the last page of the text segment will be |
| // mapped twice, once r-x and once starting out rw- and, after |
| // relocation processing, changed to r--. |
| // |
| // Ideally the last page of the text segment would not be |
| // writable even for this short period. |
| va = uint64(Rnd(int64(va), int64(*FlagRound))) |
| |
| Segrodata.Rwx = 04 |
| Segrodata.Vaddr = va |
| Segrodata.Fileoff = va - Segtext.Vaddr + Segtext.Fileoff |
| Segrodata.Filelen = 0 |
| for _, s := range Segrodata.Sections { |
| va = uint64(Rnd(int64(va), int64(s.Align))) |
| s.Vaddr = va |
| va += s.Length |
| } |
| |
| Segrodata.Length = va - Segrodata.Vaddr |
| Segrodata.Filelen = Segrodata.Length |
| } |
| if len(Segrelrodata.Sections) > 0 { |
| // align to page boundary so as not to mix |
| // rodata, rel-ro data, and executable text. |
| va = uint64(Rnd(int64(va), int64(*FlagRound))) |
| |
| Segrelrodata.Rwx = 06 |
| Segrelrodata.Vaddr = va |
| Segrelrodata.Fileoff = va - Segrodata.Vaddr + Segrodata.Fileoff |
| Segrelrodata.Filelen = 0 |
| for _, s := range Segrelrodata.Sections { |
| va = uint64(Rnd(int64(va), int64(s.Align))) |
| s.Vaddr = va |
| va += s.Length |
| } |
| |
| Segrelrodata.Length = va - Segrelrodata.Vaddr |
| Segrelrodata.Filelen = Segrelrodata.Length |
| } |
| |
| va = uint64(Rnd(int64(va), int64(*FlagRound))) |
| Segdata.Rwx = 06 |
| Segdata.Vaddr = va |
| Segdata.Fileoff = va - Segtext.Vaddr + Segtext.Fileoff |
| Segdata.Filelen = 0 |
| if Headtype == objabi.Hwindows { |
| Segdata.Fileoff = Segtext.Fileoff + uint64(Rnd(int64(Segtext.Length), PEFILEALIGN)) |
| } |
| if Headtype == objabi.Hplan9 { |
| Segdata.Fileoff = Segtext.Fileoff + Segtext.Filelen |
| } |
| var data *Section |
| var noptr *Section |
| var bss *Section |
| var noptrbss *Section |
| var vlen int64 |
| for i, s := range Segdata.Sections { |
| if Iself && s.Name == ".tbss" { |
| continue |
| } |
| vlen = int64(s.Length) |
| if i+1 < len(Segdata.Sections) && !(Iself && Segdata.Sections[i+1].Name == ".tbss") { |
| vlen = int64(Segdata.Sections[i+1].Vaddr - s.Vaddr) |
| } |
| s.Vaddr = va |
| va += uint64(vlen) |
| Segdata.Length = va - Segdata.Vaddr |
| if s.Name == ".data" { |
| data = s |
| } |
| if s.Name == ".noptrdata" { |
| noptr = s |
| } |
| if s.Name == ".bss" { |
| bss = s |
| } |
| if s.Name == ".noptrbss" { |
| noptrbss = s |
| } |
| } |
| |
| Segdata.Filelen = bss.Vaddr - Segdata.Vaddr |
| |
| va = uint64(Rnd(int64(va), int64(*FlagRound))) |
| Segdwarf.Rwx = 06 |
| Segdwarf.Vaddr = va |
| Segdwarf.Fileoff = Segdata.Fileoff + uint64(Rnd(int64(Segdata.Filelen), int64(*FlagRound))) |
| Segdwarf.Filelen = 0 |
| if Headtype == objabi.Hwindows { |
| Segdwarf.Fileoff = Segdata.Fileoff + uint64(Rnd(int64(Segdata.Filelen), int64(PEFILEALIGN))) |
| } |
| for i, s := range Segdwarf.Sections { |
| vlen = int64(s.Length) |
| if i+1 < len(Segdwarf.Sections) { |
| vlen = int64(Segdwarf.Sections[i+1].Vaddr - s.Vaddr) |
| } |
| s.Vaddr = va |
| va += uint64(vlen) |
| if Headtype == objabi.Hwindows { |
| va = uint64(Rnd(int64(va), PEFILEALIGN)) |
| } |
| Segdwarf.Length = va - Segdwarf.Vaddr |
| } |
| |
| Segdwarf.Filelen = va - Segdwarf.Vaddr |
| |
| var ( |
| text = Segtext.Sections[0] |
| rodata = ctxt.Syms.Lookup("runtime.rodata", 0).Sect |
| itablink = ctxt.Syms.Lookup("runtime.itablink", 0).Sect |
| symtab = ctxt.Syms.Lookup("runtime.symtab", 0).Sect |
| pclntab = ctxt.Syms.Lookup("runtime.pclntab", 0).Sect |
| types = ctxt.Syms.Lookup("runtime.types", 0).Sect |
| ) |
| lasttext := text |
| // Could be multiple .text sections |
| for _, sect := range Segtext.Sections { |
| if sect.Name == ".text" { |
| lasttext = sect |
| } |
| } |
| |
| for _, s := range datap { |
| if s.Sect != nil { |
| s.Value += int64(s.Sect.Vaddr) |
| } |
| for sub := s.Sub; sub != nil; sub = sub.Sub { |
| sub.Value += s.Value |
| } |
| } |
| |
| for _, sym := range dwarfp { |
| if sym.Sect != nil { |
| sym.Value += int64(sym.Sect.Vaddr) |
| } |
| for sub := sym.Sub; sub != nil; sub = sub.Sub { |
| sub.Value += sym.Value |
| } |
| } |
| |
| if Buildmode == BuildmodeShared { |
| s := ctxt.Syms.Lookup("go.link.abihashbytes", 0) |
| sectSym := ctxt.Syms.Lookup(".note.go.abihash", 0) |
| s.Sect = sectSym.Sect |
| s.Value = int64(sectSym.Sect.Vaddr + 16) |
| } |
| |
| ctxt.xdefine("runtime.text", STEXT, int64(text.Vaddr)) |
| ctxt.xdefine("runtime.etext", STEXT, int64(lasttext.Vaddr+lasttext.Length)) |
| |
| // If there are multiple text sections, create runtime.text.n for |
| // their section Vaddr, using n for index |
| n := 1 |
| for _, sect := range Segtext.Sections[1:] { |
| if sect.Name == ".text" { |
| symname := fmt.Sprintf("runtime.text.%d", n) |
| ctxt.xdefine(symname, STEXT, int64(sect.Vaddr)) |
| n++ |
| } else { |
| break |
| } |
| } |
| |
| ctxt.xdefine("runtime.rodata", SRODATA, int64(rodata.Vaddr)) |
| ctxt.xdefine("runtime.erodata", SRODATA, int64(rodata.Vaddr+rodata.Length)) |
| ctxt.xdefine("runtime.types", SRODATA, int64(types.Vaddr)) |
| ctxt.xdefine("runtime.etypes", SRODATA, int64(types.Vaddr+types.Length)) |
| ctxt.xdefine("runtime.itablink", SRODATA, int64(itablink.Vaddr)) |
| ctxt.xdefine("runtime.eitablink", SRODATA, int64(itablink.Vaddr+itablink.Length)) |
| |
| sym := ctxt.Syms.Lookup("runtime.gcdata", 0) |
| sym.Attr |= AttrLocal |
| ctxt.xdefine("runtime.egcdata", SRODATA, Symaddr(sym)+sym.Size) |
| ctxt.Syms.Lookup("runtime.egcdata", 0).Sect = sym.Sect |
| |
| sym = ctxt.Syms.Lookup("runtime.gcbss", 0) |
| sym.Attr |= AttrLocal |
| ctxt.xdefine("runtime.egcbss", SRODATA, Symaddr(sym)+sym.Size) |
| ctxt.Syms.Lookup("runtime.egcbss", 0).Sect = sym.Sect |
| |
| ctxt.xdefine("runtime.symtab", SRODATA, int64(symtab.Vaddr)) |
| ctxt.xdefine("runtime.esymtab", SRODATA, int64(symtab.Vaddr+symtab.Length)) |
| ctxt.xdefine("runtime.pclntab", SRODATA, int64(pclntab.Vaddr)) |
| ctxt.xdefine("runtime.epclntab", SRODATA, int64(pclntab.Vaddr+pclntab.Length)) |
| ctxt.xdefine("runtime.noptrdata", SNOPTRDATA, int64(noptr.Vaddr)) |
| ctxt.xdefine("runtime.enoptrdata", SNOPTRDATA, int64(noptr.Vaddr+noptr.Length)) |
| ctxt.xdefine("runtime.bss", SBSS, int64(bss.Vaddr)) |
| ctxt.xdefine("runtime.ebss", SBSS, int64(bss.Vaddr+bss.Length)) |
| ctxt.xdefine("runtime.data", SDATA, int64(data.Vaddr)) |
| ctxt.xdefine("runtime.edata", SDATA, int64(data.Vaddr+data.Length)) |
| ctxt.xdefine("runtime.noptrbss", SNOPTRBSS, int64(noptrbss.Vaddr)) |
| ctxt.xdefine("runtime.enoptrbss", SNOPTRBSS, int64(noptrbss.Vaddr+noptrbss.Length)) |
| ctxt.xdefine("runtime.end", SBSS, int64(Segdata.Vaddr+Segdata.Length)) |
| } |
| |
| // add a trampoline with symbol s (to be laid down after the current function) |
| func (ctxt *Link) AddTramp(s *Symbol) { |
| s.Type = STEXT |
| s.Attr |= AttrReachable |
| s.Attr |= AttrOnList |
| ctxt.tramps = append(ctxt.tramps, s) |
| if *FlagDebugTramp > 0 && ctxt.Debugvlog > 0 { |
| ctxt.Logf("trampoline %s inserted\n", s) |
| } |
| } |
