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data.go
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data.go
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// 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"
"cmd/link/internal/sym"
"fmt"
"log"
"os"
"sort"
"strconv"
"strings"
"sync"
)
// 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 *sym.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 *sym.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 != sym.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 *sym.Symbol) {
for ri := int32(0); ri < int32(len(s.R)); ri++ {
r := &s.R[ri]
if r.Done {
// Relocation already processed by an earlier phase.
continue
}
r.Done = true
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 == 0 && !r.Sym.Attr.VisibilityHidden()) || r.Sym.Type == sym.SXREF) {
// When putting the runtime but not main into a shared library
// these symbols are undefined and that's OK.
if ctxt.BuildMode == BuildModeShared {
if r.Sym.Name == "main.main" || r.Sym.Name == "main.init" {
r.Sym.Type = sym.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
}
if r.Type == objabi.R_DWARFFILEREF {
// These should have been processed previously during
// line table writing.
Errorf(s, "orphan R_DWARFFILEREF reloc to %v", r.Sym.Name)
continue
}
// We need to be able to reference dynimport symbols when linking against
// shared libraries, and Solaris needs it always
if ctxt.HeadType != objabi.Hsolaris && r.Sym != nil && r.Sym.Type == sym.SDYNIMPORT && !ctxt.DynlinkingGo() && !r.Sym.Attr.SubSymbol() {
if !(ctxt.Arch.Family == sys.PPC64 && ctxt.LinkMode == LinkExternal && r.Sym.Name == ".TOC.") {
Errorf(s, "unhandled relocation for %s (type %d (%s) rtype %d (%s))", r.Sym.Name, r.Sym.Type, r.Sym.Type, r.Type, sym.RelocName(ctxt.Arch, r.Type))
}
}
if r.Sym != nil && r.Sym.Type != sym.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 ctxt.Arch.Family == sys.S390X {
switch r.Type {
case objabi.R_PCRELDBL:
r.Type = objabi.R_PCREL
r.Variant = sym.RV_390_DBL
case objabi.R_CALL:
r.Variant = sym.RV_390_DBL
}
}
var o int64
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) {
Errorf(s, "unknown reloc to %v: %d (%s)", r.Sym.Name, r.Type, sym.RelocName(ctxt.Arch, r.Type))
}
case objabi.R_TLS_LE:
isAndroidX86 := objabi.GOOS == "android" && (ctxt.Arch.InFamily(sys.AMD64, sys.I386))
if ctxt.LinkMode == LinkExternal && ctxt.IsELF && !isAndroidX86 {
r.Done = false
if r.Sym == nil {
r.Sym = ctxt.Tlsg
}
r.Xsym = r.Sym
r.Xadd = r.Add
o = 0
if ctxt.Arch.Family != sys.AMD64 {
o = r.Add
}
break
}
if ctxt.IsELF && ctxt.Arch.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 ctxt.IsELF || ctxt.HeadType == objabi.Hplan9 || ctxt.HeadType == objabi.Hdarwin || isAndroidX86 {
o = int64(ctxt.Tlsoffset) + r.Add
} else if ctxt.HeadType == objabi.Hwindows {
o = r.Add
} else {
log.Fatalf("unexpected R_TLS_LE relocation for %v", ctxt.HeadType)
}
case objabi.R_TLS_IE:
isAndroidX86 := objabi.GOOS == "android" && (ctxt.Arch.InFamily(sys.AMD64, sys.I386))
if ctxt.LinkMode == LinkExternal && ctxt.IsELF && !isAndroidX86 {
r.Done = false
if r.Sym == nil {
r.Sym = ctxt.Tlsg
}
r.Xsym = r.Sym
r.Xadd = r.Add
o = 0
if ctxt.Arch.Family != sys.AMD64 {
o = r.Add
}
break
}
if ctxt.BuildMode == BuildModePIE && ctxt.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", ctxt.Arch.Family)
}
Thearch.TLSIEtoLE(s, int(off), int(r.Siz))
o = int64(ctxt.Tlsoffset)
// TODO: o += r.Add when ctxt.Arch.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 ctxt.LinkMode == LinkExternal && r.Sym.Type != sym.SCONST {
r.Done = false
// 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 != sym.SHOSTOBJ && rs.Type != sym.SDYNIMPORT && rs.Sect == nil {
Errorf(s, "missing section for relocation target %s", rs.Name)
}
r.Xsym = rs
o = r.Xadd
if ctxt.IsELF {
if ctxt.Arch.Family == sys.AMD64 {
o = 0
}
} else if ctxt.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 != sym.SHOSTOBJ {
if ctxt.Arch.Family == sys.ARM64 && rs.Dynid < 0 {
Errorf(s, "R_ADDR reloc to %s+%d is not supported on darwin/arm64", rs.Name, o)
}
if ctxt.Arch.Family != sys.ARM64 {
o += Symaddr(rs)
}
}
} else if ctxt.HeadType == objabi.Hwindows {
// nothing to do
} else {
Errorf(s, "unhandled pcrel relocation to %s on %v", rs.Name, ctxt.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 && ctxt.Arch.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_DWARFSECREF:
if r.Sym.Sect == nil {
Errorf(s, "missing DWARF section for relocation target %s", r.Sym.Name)
}
if ctxt.LinkMode == LinkExternal {
r.Done = false
// On most platforms, the external linker needs to adjust DWARF references
// as it combines DWARF sections. However, on Darwin, dsymutil does the
// DWARF linking, and it understands how to follow section offsets.
// Leaving in the relocation records confuses it (see
// https://golang.org/issue/22068) so drop them for Darwin.
if ctxt.HeadType == objabi.Hdarwin {
r.Done = true
}
// PE code emits IMAGE_REL_I386_SECREL and IMAGE_REL_AMD64_SECREL
// for R_DWARFSECREF relocations, while R_ADDR is replaced with
// IMAGE_REL_I386_DIR32, IMAGE_REL_AMD64_ADDR64 and IMAGE_REL_AMD64_ADDR32.
// Do not replace R_DWARFSECREF with R_ADDR for windows -
// let PE code emit correct relocations.
if ctxt.HeadType != objabi.Hwindows {
r.Type = objabi.R_ADDR
}
r.Xsym = ctxt.Syms.ROLookup(r.Sym.Sect.Name, 0)
r.Xadd = r.Add + Symaddr(r.Sym) - int64(r.Sym.Sect.Vaddr)
o = r.Xadd
if ctxt.IsELF && ctxt.Arch.Family == sys.AMD64 {
o = 0
}
break
}
o = Symaddr(r.Sym) + r.Add - int64(r.Sym.Sect.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
}
case objabi.R_ADDRCUOFF:
// debug_range and debug_loc elements use this relocation type to get an
// offset from the start of the compile unit.
o = Symaddr(r.Sym) + r.Add - Symaddr(r.Sym.Lib.Textp[0])
// r->sym can be null when CALL $(constant) is transformed from absolute PC to relative PC call.
case objabi.R_GOTPCREL:
if ctxt.DynlinkingGo() && ctxt.HeadType == objabi.Hdarwin && r.Sym != nil && r.Sym.Type != sym.SCONST {
r.Done = false
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 ctxt.LinkMode == LinkExternal && r.Sym != nil && r.Sym.Type != sym.SCONST && (r.Sym.Sect != s.Sect || r.Type == objabi.R_GOTPCREL) {
r.Done = false
// 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 != sym.SHOSTOBJ && rs.Type != sym.SDYNIMPORT && rs.Sect == nil {
Errorf(s, "missing section for relocation target %s", rs.Name)
}
r.Xsym = rs
o = r.Xadd
if ctxt.IsELF {
if ctxt.Arch.Family == sys.AMD64 {
o = 0
}
} else if ctxt.HeadType == objabi.Hdarwin {
if r.Type == objabi.R_CALL {
if rs.Type != sym.SHOSTOBJ {
o += int64(uint64(Symaddr(rs)) - rs.Sect.Vaddr)
}
o -= int64(r.Off) // relative to section offset, not symbol
} else if ctxt.Arch.Family == sys.ARM {
// see ../arm/asm.go:/machoreloc1
o += Symaddr(rs) - int64(s.Value) - int64(r.Off)
} else {
o += int64(r.Siz)
}
} else if ctxt.HeadType == objabi.Hwindows && ctxt.Arch.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, ctxt.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 != sym.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 (%s)/%d, %x]\n", s.Name, s.Value+int64(off), s.Value, r.Off, r.Siz, nam, Symaddr(r.Sym), r.Add, r.Type, sym.RelocName(ctxt.Arch, 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 _, s := range datap {
relocsym(ctxt, s)
}
for _, s := range dwarfp {
relocsym(ctxt, s)
}
}
func windynrelocsym(ctxt *Link, s *sym.Symbol) {
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 ctxt.Arch.Family == sys.I386 {
rel.AddUint8(0xff)
rel.AddUint8(0x25)
rel.AddAddr(ctxt.Arch, targ)
rel.AddUint8(0x90)
rel.AddUint8(0x90)
} else {
rel.AddUint8(0xff)
rel.AddUint8(0x24)
rel.AddUint8(0x25)
rel.AddAddrPlus4(targ, 0)
rel.AddUint8(0x90)
}
} else if r.Sym.Plt >= 0 {
r.Sym = rel
r.Add = int64(targ.Plt)
}
}
}
func dynrelocsym(ctxt *Link, s *sym.Symbol) {
if ctxt.HeadType == objabi.Hwindows {
if ctxt.LinkMode == LinkInternal {
windynrelocsym(ctxt, s)
}
return
}
for ri := 0; ri < len(s.R); ri++ {
r := &s.R[ri]
if ctxt.BuildMode == BuildModePIE && ctxt.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 == sym.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 (%s) stype=%d (%s))", r.Sym.Name, r.Type, sym.RelocName(ctxt.Arch, r.Type), r.Sym.Type, r.Sym.Type)
}
}
}
}
func dynreloc(ctxt *Link, data *[sym.SXREF][]*sym.Symbol) {
// -d suppresses dynamic loader format, so we may as well not
// compute these sections or mark their symbols as reachable.
if *FlagD && ctxt.HeadType != objabi.Hwindows {
return
}
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f dynreloc\n", Cputime())
}
for _, s := range ctxt.Textp {
dynrelocsym(ctxt, s)
}
for _, syms := range data {
for _, s := range syms {
dynrelocsym(ctxt, s)
}
}
if ctxt.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, ctxt.Out.Offset())
}
blk(ctxt, ctxt.Textp, addr, size, pad)
/* again for printing */
if !*flagA {
return
}
syms := ctxt.Textp
for i, s := range syms {
if !s.Attr.Reachable() {
continue
}
if s.Value >= addr {
syms = syms[i:]
break
}
}
eaddr := addr + size
var q []byte
for _, s := range syms {
if !s.Attr.Reachable() {
continue
}
if s.Value >= eaddr {
break
}
if addr < s.Value {
ctxt.Logf("%-20s %.8x|", "_", uint64(addr))
for ; addr < s.Value; addr++ {
ctxt.Logf(" %.2x", 0)
}
ctxt.Logf("\n")
}
ctxt.Logf("%.6x\t%-20s\n", uint64(addr), s.Name)
q = s.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 []*sym.Symbol, addr, size int64, pad []byte) {
for i, s := range syms {
if !s.Attr.SubSymbol() && s.Value >= addr {
syms = syms[i:]
break
}
}
eaddr := addr + size
for _, s := range syms {
if s.Attr.SubSymbol() {
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 {
ctxt.Out.WriteStringPad("", int(s.Value-addr), pad)
addr = s.Value
}
ctxt.Out.Write(s.P)
addr += int64(len(s.P))
if addr < s.Value+s.Size {
ctxt.Out.WriteStringPad("", 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 {
ctxt.Out.WriteStringPad("", int(eaddr-addr), pad)
}
ctxt.Out.Flush()
}
func Datblk(ctxt *Link, addr int64, size int64) {
if *flagA {
ctxt.Logf("datblk [%#x,%#x) at offset %#x\n", addr, addr+size, ctxt.Out.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 ctxt.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, ctxt.Out.Offset())
}
blk(ctxt, dwarfp, addr, size, zeros[:])
}
var zeros [512]byte
var strdata []*sym.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")
}
pkg := arg[:dot]
if ctxt.BuildMode == BuildModePlugin && pkg == "main" {
pkg = *flagPluginPath
}
pkg = objabi.PathToPrefix(pkg)
addstrdata(ctxt, pkg+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 = sym.SRODATA
s := ctxt.Syms.Lookup(name, 0)
s.Size = 0
s.Attr |= sym.AttrDuplicateOK
reachable := s.Attr.Reachable()
s.AddAddr(ctxt.Arch, sp)
s.AddUint(ctxt.Arch, uint64(len(value)))
// 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(sym.AttrReachable, reachable)
strdata = append(strdata, s)
sp.Attr.Set(sym.AttrReachable, reachable)
}
func (ctxt *Link) checkstrdata() {
for _, s := range strdata {
if s.Type == sym.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 *sym.Symbol, str string) int64 {
if s.Type == 0 {
s.Type = sym.SNOPTRDATA
}
s.Attr |= sym.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 *sym.Symbol, symname, str string) {
sdata := ctxt.Syms.Lookup(symname, 0)
if sdata.Type != sym.Sxxx {
Errorf(s, "duplicate symname in addgostring: %s", symname)
}
sdata.Attr |= sym.AttrReachable
sdata.Attr |= sym.AttrLocal
sdata.Type = sym.SRODATA
sdata.Size = int64(len(str))
sdata.P = []byte(str)
s.AddAddr(ctxt.Arch, sdata)
s.AddUint(ctxt.Arch, uint64(len(str)))
}
func addinitarrdata(ctxt *Link, s *sym.Symbol) {
p := s.Name + ".ptr"
sp := ctxt.Syms.Lookup(p, 0)
sp.Type = sym.SINITARR
sp.Size = 0
sp.Attr |= sym.AttrDuplicateOK
sp.AddAddr(ctxt.Arch, s)
}
func dosymtype(ctxt *Link) {
switch ctxt.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.
if s.Name == *flagEntrySymbol {
addinitarrdata(ctxt, s)
}
}
}
}
// symalign returns the required alignment for the given symbol s.
func symalign(s *sym.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 *sym.Symbol) int64 {
return Rnd(datsize, int64(symalign(s)))
}
const debugGCProg = false
type GCProg struct {
ctxt *Link
sym *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) {
p.sym.AddUint8(x)
}
}
func (p *GCProg) End(size int64) {
p.w.ZeroUntil(size / int64(p.ctxt.Arch.PtrSize))
p.w.End()
if debugGCProg {
fmt.Fprintf(os.Stderr, "ld: end GCProg\n")
}
}
func (p *GCProg) AddSym(s *sym.Symbol) {
typ := s.Gotype
// Things without pointers should be in sym.SNOPTRDATA or sym.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(p.ctxt.Arch.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(p.ctxt.Arch, 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 *sym.Symbol pointers.
// The sort keys are kept inline to improve cache behavior while sorting.
type dataSortKey struct {
size int64
name string
sym *sym.Symbol
}
type bySizeAndName []dataSortKey