Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 861 insertions, 0 deletions

diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go
new file mode 100644
index 0000000..bb58b4f
--- /dev/null
+++ b/src/cmd/internal/obj/objfile.go
@@ -0,0 +1,861 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Writing Go object files.
+
+package obj
+
+import (
+	"bytes"
+	"cmd/internal/bio"
+	"cmd/internal/goobj"
+	"cmd/internal/objabi"
+	"cmd/internal/sys"
+	"crypto/sha1"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+// Entry point of writing new object file.
+func WriteObjFile(ctxt *Link, b *bio.Writer) {
+
+	debugAsmEmit(ctxt)
+
+	genFuncInfoSyms(ctxt)
+
+	w := writer{
+		Writer:  goobj.NewWriter(b),
+		ctxt:    ctxt,
+		pkgpath: objabi.PathToPrefix(ctxt.Pkgpath),
+	}
+
+	start := b.Offset()
+	w.init()
+
+	// Header
+	// We just reserve the space. We'll fill in the offsets later.
+	flags := uint32(0)
+	if ctxt.Flag_shared {
+		flags |= goobj.ObjFlagShared
+	}
+	if w.pkgpath == "" {
+		flags |= goobj.ObjFlagNeedNameExpansion
+	}
+	if ctxt.IsAsm {
+		flags |= goobj.ObjFlagFromAssembly
+	}
+	h := goobj.Header{
+		Magic:       goobj.Magic,
+		Fingerprint: ctxt.Fingerprint,
+		Flags:       flags,
+	}
+	h.Write(w.Writer)
+
+	// String table
+	w.StringTable()
+
+	// Autolib
+	h.Offsets[goobj.BlkAutolib] = w.Offset()
+	for i := range ctxt.Imports {
+		ctxt.Imports[i].Write(w.Writer)
+	}
+
+	// Package references
+	h.Offsets[goobj.BlkPkgIdx] = w.Offset()
+	for _, pkg := range w.pkglist {
+		w.StringRef(pkg)
+	}
+
+	// File table (for DWARF and pcln generation).
+	h.Offsets[goobj.BlkFile] = w.Offset()
+	for _, f := range ctxt.PosTable.FileTable() {
+		w.StringRef(filepath.ToSlash(f))
+	}
+
+	// Symbol definitions
+	h.Offsets[goobj.BlkSymdef] = w.Offset()
+	for _, s := range ctxt.defs {
+		w.Sym(s)
+	}
+
+	// Short hashed symbol definitions
+	h.Offsets[goobj.BlkHashed64def] = w.Offset()
+	for _, s := range ctxt.hashed64defs {
+		w.Sym(s)
+	}
+
+	// Hashed symbol definitions
+	h.Offsets[goobj.BlkHasheddef] = w.Offset()
+	for _, s := range ctxt.hasheddefs {
+		w.Sym(s)
+	}
+
+	// Non-pkg symbol definitions
+	h.Offsets[goobj.BlkNonpkgdef] = w.Offset()
+	for _, s := range ctxt.nonpkgdefs {
+		w.Sym(s)
+	}
+
+	// Non-pkg symbol references
+	h.Offsets[goobj.BlkNonpkgref] = w.Offset()
+	for _, s := range ctxt.nonpkgrefs {
+		w.Sym(s)
+	}
+
+	// Referenced package symbol flags
+	h.Offsets[goobj.BlkRefFlags] = w.Offset()
+	w.refFlags()
+
+	// Hashes
+	h.Offsets[goobj.BlkHash64] = w.Offset()
+	for _, s := range ctxt.hashed64defs {
+		w.Hash64(s)
+	}
+	h.Offsets[goobj.BlkHash] = w.Offset()
+	for _, s := range ctxt.hasheddefs {
+		w.Hash(s)
+	}
+	// TODO: hashedrefs unused/unsupported for now
+
+	// Reloc indexes
+	h.Offsets[goobj.BlkRelocIdx] = w.Offset()
+	nreloc := uint32(0)
+	lists := [][]*LSym{ctxt.defs, ctxt.hashed64defs, ctxt.hasheddefs, ctxt.nonpkgdefs}
+	for _, list := range lists {
+		for _, s := range list {
+			w.Uint32(nreloc)
+			nreloc += uint32(len(s.R))
+		}
+	}
+	w.Uint32(nreloc)
+
+	// Symbol Info indexes
+	h.Offsets[goobj.BlkAuxIdx] = w.Offset()
+	naux := uint32(0)
+	for _, list := range lists {
+		for _, s := range list {
+			w.Uint32(naux)
+			naux += uint32(nAuxSym(s))
+		}
+	}
+	w.Uint32(naux)
+
+	// Data indexes
+	h.Offsets[goobj.BlkDataIdx] = w.Offset()
+	dataOff := int64(0)
+	for _, list := range lists {
+		for _, s := range list {
+			w.Uint32(uint32(dataOff))
+			dataOff += int64(len(s.P))
+			if file := s.File(); file != nil {
+				dataOff += int64(file.Size)
+			}
+		}
+	}
+	if int64(uint32(dataOff)) != dataOff {
+		log.Fatalf("data too large")
+	}
+	w.Uint32(uint32(dataOff))
+
+	// Relocs
+	h.Offsets[goobj.BlkReloc] = w.Offset()
+	for _, list := range lists {
+		for _, s := range list {
+			for i := range s.R {
+				w.Reloc(&s.R[i])
+			}
+		}
+	}
+
+	// Aux symbol info
+	h.Offsets[goobj.BlkAux] = w.Offset()
+	for _, list := range lists {
+		for _, s := range list {
+			w.Aux(s)
+		}
+	}
+
+	// Data
+	h.Offsets[goobj.BlkData] = w.Offset()
+	for _, list := range lists {
+		for _, s := range list {
+			w.Bytes(s.P)
+			if file := s.File(); file != nil {
+				w.writeFile(ctxt, file)
+			}
+		}
+	}
+
+	// Pcdata
+	h.Offsets[goobj.BlkPcdata] = w.Offset()
+	for _, s := range ctxt.Text { // iteration order must match genFuncInfoSyms
+		// Because of the phase order, it's possible that we try to write an invalid
+		// object file, and the Pcln variables haven't been filled in. As such, we
+		// need to check that Pcsp exists, and assume the other pcln variables exist
+		// as well. Tests like test/fixedbugs/issue22200.go demonstrate this issue.
+		if fn := s.Func(); fn != nil && fn.Pcln.Pcsp != nil {
+			pc := &fn.Pcln
+			w.Bytes(pc.Pcsp.P)
+			w.Bytes(pc.Pcfile.P)
+			w.Bytes(pc.Pcline.P)
+			w.Bytes(pc.Pcinline.P)
+			for i := range pc.Pcdata {
+				w.Bytes(pc.Pcdata[i].P)
+			}
+		}
+	}
+
+	// Blocks used only by tools (objdump, nm).
+
+	// Referenced symbol names from other packages
+	h.Offsets[goobj.BlkRefName] = w.Offset()
+	w.refNames()
+
+	h.Offsets[goobj.BlkEnd] = w.Offset()
+
+	// Fix up block offsets in the header
+	end := start + int64(w.Offset())
+	b.MustSeek(start, 0)
+	h.Write(w.Writer)
+	b.MustSeek(end, 0)
+}
+
+type writer struct {
+	*goobj.Writer
+	filebuf []byte
+	ctxt    *Link
+	pkgpath string   // the package import path (escaped), "" if unknown
+	pkglist []string // list of packages referenced, indexed by ctxt.pkgIdx
+}
+
+// prepare package index list
+func (w *writer) init() {
+	w.pkglist = make([]string, len(w.ctxt.pkgIdx)+1)
+	w.pkglist[0] = "" // dummy invalid package for index 0
+	for pkg, i := range w.ctxt.pkgIdx {
+		w.pkglist[i] = pkg
+	}
+}
+
+func (w *writer) writeFile(ctxt *Link, file *FileInfo) {
+	f, err := os.Open(file.Name)
+	if err != nil {
+		ctxt.Diag("%v", err)
+		return
+	}
+	defer f.Close()
+	if w.filebuf == nil {
+		w.filebuf = make([]byte, 1024)
+	}
+	buf := w.filebuf
+	written := int64(0)
+	for {
+		n, err := f.Read(buf)
+		w.Bytes(buf[:n])
+		written += int64(n)
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			ctxt.Diag("%v", err)
+			return
+		}
+	}
+	if written != file.Size {
+		ctxt.Diag("copy %s: unexpected length %d != %d", file.Name, written, file.Size)
+	}
+}
+
+func (w *writer) StringTable() {
+	w.AddString("")
+	for _, p := range w.ctxt.Imports {
+		w.AddString(p.Pkg)
+	}
+	for _, pkg := range w.pkglist {
+		w.AddString(pkg)
+	}
+	w.ctxt.traverseSyms(traverseAll, func(s *LSym) {
+		// TODO: this includes references of indexed symbols from other packages,
+		// for which the linker doesn't need the name. Consider moving them to
+		// a separate block (for tools only).
+		if w.pkgpath != "" {
+			s.Name = strings.Replace(s.Name, "\"\".", w.pkgpath+".", -1)
+		}
+		// Don't put names of builtins into the string table (to save
+		// space).
+		if s.PkgIdx == goobj.PkgIdxBuiltin {
+			return
+		}
+		w.AddString(s.Name)
+	})
+
+	// All filenames are in the postable.
+	for _, f := range w.ctxt.PosTable.FileTable() {
+		w.AddString(filepath.ToSlash(f))
+	}
+}
+
+// cutoff is the maximum data section size permitted by the linker
+// (see issue #9862).
+const cutoff = int64(2e9) // 2 GB (or so; looks better in errors than 2^31)
+
+func (w *writer) Sym(s *LSym) {
+	abi := uint16(s.ABI())
+	if s.Static() {
+		abi = goobj.SymABIstatic
+	}
+	flag := uint8(0)
+	if s.DuplicateOK() {
+		flag |= goobj.SymFlagDupok
+	}
+	if s.Local() {
+		flag |= goobj.SymFlagLocal
+	}
+	if s.MakeTypelink() {
+		flag |= goobj.SymFlagTypelink
+	}
+	if s.Leaf() {
+		flag |= goobj.SymFlagLeaf
+	}
+	if s.NoSplit() {
+		flag |= goobj.SymFlagNoSplit
+	}
+	if s.ReflectMethod() {
+		flag |= goobj.SymFlagReflectMethod
+	}
+	if s.TopFrame() {
+		flag |= goobj.SymFlagTopFrame
+	}
+	if strings.HasPrefix(s.Name, "type.") && s.Name[5] != '.' && s.Type == objabi.SRODATA {
+		flag |= goobj.SymFlagGoType
+	}
+	flag2 := uint8(0)
+	if s.UsedInIface() {
+		flag2 |= goobj.SymFlagUsedInIface
+	}
+	if strings.HasPrefix(s.Name, "go.itab.") && s.Type == objabi.SRODATA {
+		flag2 |= goobj.SymFlagItab
+	}
+	name := s.Name
+	if strings.HasPrefix(name, "gofile..") {
+		name = filepath.ToSlash(name)
+	}
+	var align uint32
+	if fn := s.Func(); fn != nil {
+		align = uint32(fn.Align)
+	}
+	if s.ContentAddressable() {
+		// We generally assume data symbols are natually aligned,
+		// except for strings. If we dedup a string symbol and a
+		// non-string symbol with the same content, we should keep
+		// the largest alignment.
+		// TODO: maybe the compiler could set the alignment for all
+		// data symbols more carefully.
+		if s.Size != 0 && !strings.HasPrefix(s.Name, "go.string.") {
+			switch {
+			case w.ctxt.Arch.PtrSize == 8 && s.Size%8 == 0:
+				align = 8
+			case s.Size%4 == 0:
+				align = 4
+			case s.Size%2 == 0:
+				align = 2
+			}
+			// don't bother setting align to 1.
+		}
+	}
+	if s.Size > cutoff {
+		w.ctxt.Diag("%s: symbol too large (%d bytes > %d bytes)", s.Name, s.Size, cutoff)
+	}
+	var o goobj.Sym
+	o.SetName(name, w.Writer)
+	o.SetABI(abi)
+	o.SetType(uint8(s.Type))
+	o.SetFlag(flag)
+	o.SetFlag2(flag2)
+	o.SetSiz(uint32(s.Size))
+	o.SetAlign(align)
+	o.Write(w.Writer)
+}
+
+func (w *writer) Hash64(s *LSym) {
+	if !s.ContentAddressable() || len(s.R) != 0 {
+		panic("Hash of non-content-addresable symbol")
+	}
+	b := contentHash64(s)
+	w.Bytes(b[:])
+}
+
+func (w *writer) Hash(s *LSym) {
+	if !s.ContentAddressable() {
+		panic("Hash of non-content-addresable symbol")
+	}
+	b := w.contentHash(s)
+	w.Bytes(b[:])
+}
+
+func contentHash64(s *LSym) goobj.Hash64Type {
+	var b goobj.Hash64Type
+	copy(b[:], s.P)
+	return b
+}
+
+// Compute the content hash for a content-addressable symbol.
+// We build a content hash based on its content and relocations.
+// Depending on the category of the referenced symbol, we choose
+// different hash algorithms such that the hash is globally
+// consistent.
+// - For referenced content-addressable symbol, its content hash
+//   is globally consistent.
+// - For package symbol and builtin symbol, its local index is
+//   globally consistent.
+// - For non-package symbol, its fully-expanded name is globally
+//   consistent. For now, we require we know the current package
+//   path so we can always expand symbol names. (Otherwise,
+//   symbols with relocations are not considered hashable.)
+//
+// For now, we assume there is no circular dependencies among
+// hashed symbols.
+func (w *writer) contentHash(s *LSym) goobj.HashType {
+	h := sha1.New()
+	var tmp [14]byte
+
+	// Include the size of the symbol in the hash.
+	// This preserves the length of symbols, preventing the following two symbols
+	// from hashing the same:
+	//
+	//    [2]int{1,2} ≠ [10]int{1,2,0,0,0...}
+	//
+	// In this case, if the smaller symbol is alive, the larger is not kept unless
+	// needed.
+	binary.LittleEndian.PutUint64(tmp[:8], uint64(s.Size))
+	h.Write(tmp[:8])
+
+	// Don't dedup type symbols with others, as they are in a different
+	// section.
+	if strings.HasPrefix(s.Name, "type.") {
+		h.Write([]byte{'T'})
+	} else {
+		h.Write([]byte{0})
+	}
+	// The compiler trims trailing zeros _sometimes_. We just do
+	// it always.
+	h.Write(bytes.TrimRight(s.P, "\x00"))
+	for i := range s.R {
+		r := &s.R[i]
+		binary.LittleEndian.PutUint32(tmp[:4], uint32(r.Off))
+		tmp[4] = r.Siz
+		tmp[5] = uint8(r.Type)
+		binary.LittleEndian.PutUint64(tmp[6:14], uint64(r.Add))
+		h.Write(tmp[:])
+		rs := r.Sym
+		switch rs.PkgIdx {
+		case goobj.PkgIdxHashed64:
+			h.Write([]byte{0})
+			t := contentHash64(rs)
+			h.Write(t[:])
+		case goobj.PkgIdxHashed:
+			h.Write([]byte{1})
+			t := w.contentHash(rs)
+			h.Write(t[:])
+		case goobj.PkgIdxNone:
+			h.Write([]byte{2})
+			io.WriteString(h, rs.Name) // name is already expanded at this point
+		case goobj.PkgIdxBuiltin:
+			h.Write([]byte{3})
+			binary.LittleEndian.PutUint32(tmp[:4], uint32(rs.SymIdx))
+			h.Write(tmp[:4])
+		case goobj.PkgIdxSelf:
+			io.WriteString(h, w.pkgpath)
+			binary.LittleEndian.PutUint32(tmp[:4], uint32(rs.SymIdx))
+			h.Write(tmp[:4])
+		default:
+			io.WriteString(h, rs.Pkg)
+			binary.LittleEndian.PutUint32(tmp[:4], uint32(rs.SymIdx))
+			h.Write(tmp[:4])
+		}
+	}
+	var b goobj.HashType
+	copy(b[:], h.Sum(nil))
+	return b
+}
+
+func makeSymRef(s *LSym) goobj.SymRef {
+	if s == nil {
+		return goobj.SymRef{}
+	}
+	if s.PkgIdx == 0 || !s.Indexed() {
+		fmt.Printf("unindexed symbol reference: %v\n", s)
+		panic("unindexed symbol reference")
+	}
+	return goobj.SymRef{PkgIdx: uint32(s.PkgIdx), SymIdx: uint32(s.SymIdx)}
+}
+
+func (w *writer) Reloc(r *Reloc) {
+	var o goobj.Reloc
+	o.SetOff(r.Off)
+	o.SetSiz(r.Siz)
+	o.SetType(uint8(r.Type))
+	o.SetAdd(r.Add)
+	o.SetSym(makeSymRef(r.Sym))
+	o.Write(w.Writer)
+}
+
+func (w *writer) aux1(typ uint8, rs *LSym) {
+	var o goobj.Aux
+	o.SetType(typ)
+	o.SetSym(makeSymRef(rs))
+	o.Write(w.Writer)
+}
+
+func (w *writer) Aux(s *LSym) {
+	if s.Gotype != nil {
+		w.aux1(goobj.AuxGotype, s.Gotype)
+	}
+	if fn := s.Func(); fn != nil {
+		w.aux1(goobj.AuxFuncInfo, fn.FuncInfoSym)
+
+		for _, d := range fn.Pcln.Funcdata {
+			w.aux1(goobj.AuxFuncdata, d)
+		}
+
+		if fn.dwarfInfoSym != nil && fn.dwarfInfoSym.Size != 0 {
+			w.aux1(goobj.AuxDwarfInfo, fn.dwarfInfoSym)
+		}
+		if fn.dwarfLocSym != nil && fn.dwarfLocSym.Size != 0 {
+			w.aux1(goobj.AuxDwarfLoc, fn.dwarfLocSym)
+		}
+		if fn.dwarfRangesSym != nil && fn.dwarfRangesSym.Size != 0 {
+			w.aux1(goobj.AuxDwarfRanges, fn.dwarfRangesSym)
+		}
+		if fn.dwarfDebugLinesSym != nil && fn.dwarfDebugLinesSym.Size != 0 {
+			w.aux1(goobj.AuxDwarfLines, fn.dwarfDebugLinesSym)
+		}
+		if fn.Pcln.Pcsp != nil && fn.Pcln.Pcsp.Size != 0 {
+			w.aux1(goobj.AuxPcsp, fn.Pcln.Pcsp)
+		}
+		if fn.Pcln.Pcfile != nil && fn.Pcln.Pcfile.Size != 0 {
+			w.aux1(goobj.AuxPcfile, fn.Pcln.Pcfile)
+		}
+		if fn.Pcln.Pcline != nil && fn.Pcln.Pcline.Size != 0 {
+			w.aux1(goobj.AuxPcline, fn.Pcln.Pcline)
+		}
+		if fn.Pcln.Pcinline != nil && fn.Pcln.Pcinline.Size != 0 {
+			w.aux1(goobj.AuxPcinline, fn.Pcln.Pcinline)
+		}
+		for _, pcSym := range fn.Pcln.Pcdata {
+			w.aux1(goobj.AuxPcdata, pcSym)
+		}
+
+	}
+}
+
+// Emits flags of referenced indexed symbols.
+func (w *writer) refFlags() {
+	seen := make(map[*LSym]bool)
+	w.ctxt.traverseSyms(traverseRefs, func(rs *LSym) { // only traverse refs, not auxs, as tools don't need auxs
+		switch rs.PkgIdx {
+		case goobj.PkgIdxNone, goobj.PkgIdxHashed64, goobj.PkgIdxHashed, goobj.PkgIdxBuiltin, goobj.PkgIdxSelf: // not an external indexed reference
+			return
+		case goobj.PkgIdxInvalid:
+			panic("unindexed symbol reference")
+		}
+		if seen[rs] {
+			return
+		}
+		seen[rs] = true
+		symref := makeSymRef(rs)
+		flag2 := uint8(0)
+		if rs.UsedInIface() {
+			flag2 |= goobj.SymFlagUsedInIface
+		}
+		if flag2 == 0 {
+			return // no need to write zero flags
+		}
+		var o goobj.RefFlags
+		o.SetSym(symref)
+		o.SetFlag2(flag2)
+		o.Write(w.Writer)
+	})
+}
+
+// Emits names of referenced indexed symbols, used by tools (objdump, nm)
+// only.
+func (w *writer) refNames() {
+	seen := make(map[*LSym]bool)
+	w.ctxt.traverseSyms(traverseRefs, func(rs *LSym) { // only traverse refs, not auxs, as tools don't need auxs
+		switch rs.PkgIdx {
+		case goobj.PkgIdxNone, goobj.PkgIdxHashed64, goobj.PkgIdxHashed, goobj.PkgIdxBuiltin, goobj.PkgIdxSelf: // not an external indexed reference
+			return
+		case goobj.PkgIdxInvalid:
+			panic("unindexed symbol reference")
+		}
+		if seen[rs] {
+			return
+		}
+		seen[rs] = true
+		symref := makeSymRef(rs)
+		var o goobj.RefName
+		o.SetSym(symref)
+		o.SetName(rs.Name, w.Writer)
+		o.Write(w.Writer)
+	})
+	// TODO: output in sorted order?
+	// Currently tools (cmd/internal/goobj package) doesn't use mmap,
+	// and it just read it into a map in memory upfront. If it uses
+	// mmap, if the output is sorted, it probably could avoid reading
+	// into memory and just do lookups in the mmap'd object file.
+}
+
+// return the number of aux symbols s have.
+func nAuxSym(s *LSym) int {
+	n := 0
+	if s.Gotype != nil {
+		n++
+	}
+	if fn := s.Func(); fn != nil {
+		// FuncInfo is an aux symbol, each Funcdata is an aux symbol
+		n += 1 + len(fn.Pcln.Funcdata)
+		if fn.dwarfInfoSym != nil && fn.dwarfInfoSym.Size != 0 {
+			n++
+		}
+		if fn.dwarfLocSym != nil && fn.dwarfLocSym.Size != 0 {
+			n++
+		}
+		if fn.dwarfRangesSym != nil && fn.dwarfRangesSym.Size != 0 {
+			n++
+		}
+		if fn.dwarfDebugLinesSym != nil && fn.dwarfDebugLinesSym.Size != 0 {
+			n++
+		}
+		if fn.Pcln.Pcsp != nil && fn.Pcln.Pcsp.Size != 0 {
+			n++
+		}
+		if fn.Pcln.Pcfile != nil && fn.Pcln.Pcfile.Size != 0 {
+			n++
+		}
+		if fn.Pcln.Pcline != nil && fn.Pcln.Pcline.Size != 0 {
+			n++
+		}
+		if fn.Pcln.Pcinline != nil && fn.Pcln.Pcinline.Size != 0 {
+			n++
+		}
+		n += len(fn.Pcln.Pcdata)
+	}
+	return n
+}
+
+// generate symbols for FuncInfo.
+func genFuncInfoSyms(ctxt *Link) {
+	infosyms := make([]*LSym, 0, len(ctxt.Text))
+	hashedsyms := make([]*LSym, 0, 4*len(ctxt.Text))
+	preparePcSym := func(s *LSym) *LSym {
+		if s == nil {
+			return s
+		}
+		s.PkgIdx = goobj.PkgIdxHashed
+		s.SymIdx = int32(len(hashedsyms) + len(ctxt.hasheddefs))
+		s.Set(AttrIndexed, true)
+		hashedsyms = append(hashedsyms, s)
+		return s
+	}
+	var b bytes.Buffer
+	symidx := int32(len(ctxt.defs))
+	for _, s := range ctxt.Text {
+		fn := s.Func()
+		if fn == nil {
+			continue
+		}
+		o := goobj.FuncInfo{
+			Args:   uint32(fn.Args),
+			Locals: uint32(fn.Locals),
+			FuncID: objabi.FuncID(fn.FuncID),
+		}
+		pc := &fn.Pcln
+		o.Pcsp = makeSymRef(preparePcSym(pc.Pcsp))
+		o.Pcfile = makeSymRef(preparePcSym(pc.Pcfile))
+		o.Pcline = makeSymRef(preparePcSym(pc.Pcline))
+		o.Pcinline = makeSymRef(preparePcSym(pc.Pcinline))
+		o.Pcdata = make([]goobj.SymRef, len(pc.Pcdata))
+		for i, pcSym := range pc.Pcdata {
+			o.Pcdata[i] = makeSymRef(preparePcSym(pcSym))
+		}
+		o.Funcdataoff = make([]uint32, len(pc.Funcdataoff))
+		for i, x := range pc.Funcdataoff {
+			o.Funcdataoff[i] = uint32(x)
+		}
+		i := 0
+		o.File = make([]goobj.CUFileIndex, len(pc.UsedFiles))
+		for f := range pc.UsedFiles {
+			o.File[i] = f
+			i++
+		}
+		sort.Slice(o.File, func(i, j int) bool { return o.File[i] < o.File[j] })
+		o.InlTree = make([]goobj.InlTreeNode, len(pc.InlTree.nodes))
+		for i, inl := range pc.InlTree.nodes {
+			f, l := getFileIndexAndLine(ctxt, inl.Pos)
+			o.InlTree[i] = goobj.InlTreeNode{
+				Parent:   int32(inl.Parent),
+				File:     goobj.CUFileIndex(f),
+				Line:     l,
+				Func:     makeSymRef(inl.Func),
+				ParentPC: inl.ParentPC,
+			}
+		}
+
+		o.Write(&b)
+		isym := &LSym{
+			Type:   objabi.SDATA, // for now, I don't think it matters
+			PkgIdx: goobj.PkgIdxSelf,
+			SymIdx: symidx,
+			P:      append([]byte(nil), b.Bytes()...),
+		}
+		isym.Set(AttrIndexed, true)
+		symidx++
+		infosyms = append(infosyms, isym)
+		fn.FuncInfoSym = isym
+		b.Reset()
+
+		dwsyms := []*LSym{fn.dwarfRangesSym, fn.dwarfLocSym, fn.dwarfDebugLinesSym, fn.dwarfInfoSym}
+		for _, s := range dwsyms {
+			if s == nil || s.Size == 0 {
+				continue
+			}
+			s.PkgIdx = goobj.PkgIdxSelf
+			s.SymIdx = symidx
+			s.Set(AttrIndexed, true)
+			symidx++
+			infosyms = append(infosyms, s)
+		}
+	}
+	ctxt.defs = append(ctxt.defs, infosyms...)
+	ctxt.hasheddefs = append(ctxt.hasheddefs, hashedsyms...)
+}
+
+func writeAuxSymDebug(ctxt *Link, par *LSym, aux *LSym) {
+	// Most aux symbols (ex: funcdata) are not interesting--
+	// pick out just the DWARF ones for now.
+	if aux.Type != objabi.SDWARFLOC &&
+		aux.Type != objabi.SDWARFFCN &&
+		aux.Type != objabi.SDWARFABSFCN &&
+		aux.Type != objabi.SDWARFLINES &&
+		aux.Type != objabi.SDWARFRANGE {
+		return
+	}
+	ctxt.writeSymDebugNamed(aux, "aux for "+par.Name)
+}
+
+func debugAsmEmit(ctxt *Link) {
+	if ctxt.Debugasm > 0 {
+		ctxt.traverseSyms(traverseDefs, ctxt.writeSymDebug)
+		if ctxt.Debugasm > 1 {
+			fn := func(par *LSym, aux *LSym) {
+				writeAuxSymDebug(ctxt, par, aux)
+			}
+			ctxt.traverseAuxSyms(traverseAux, fn)
+		}
+	}
+}
+
+func (ctxt *Link) writeSymDebug(s *LSym) {
+	ctxt.writeSymDebugNamed(s, s.Name)
+}
+
+func (ctxt *Link) writeSymDebugNamed(s *LSym, name string) {
+	ver := ""
+	if ctxt.Debugasm > 1 {
+		ver = fmt.Sprintf("<%d>", s.ABI())
+	}
+	fmt.Fprintf(ctxt.Bso, "%s%s ", name, ver)
+	if s.Type != 0 {
+		fmt.Fprintf(ctxt.Bso, "%v ", s.Type)
+	}
+	if s.Static() {
+		fmt.Fprint(ctxt.Bso, "static ")
+	}
+	if s.DuplicateOK() {
+		fmt.Fprintf(ctxt.Bso, "dupok ")
+	}
+	if s.CFunc() {
+		fmt.Fprintf(ctxt.Bso, "cfunc ")
+	}
+	if s.NoSplit() {
+		fmt.Fprintf(ctxt.Bso, "nosplit ")
+	}
+	if s.TopFrame() {
+		fmt.Fprintf(ctxt.Bso, "topframe ")
+	}
+	fmt.Fprintf(ctxt.Bso, "size=%d", s.Size)
+	if s.Type == objabi.STEXT {
+		fn := s.Func()
+		fmt.Fprintf(ctxt.Bso, " args=%#x locals=%#x funcid=%#x", uint64(fn.Args), uint64(fn.Locals), uint64(fn.FuncID))
+		if s.Leaf() {
+			fmt.Fprintf(ctxt.Bso, " leaf")
+		}
+	}
+	fmt.Fprintf(ctxt.Bso, "\n")
+	if s.Type == objabi.STEXT {
+		for p := s.Func().Text; p != nil; p = p.Link {
+			fmt.Fprintf(ctxt.Bso, "\t%#04x ", uint(int(p.Pc)))
+			if ctxt.Debugasm > 1 {
+				io.WriteString(ctxt.Bso, p.String())
+			} else {
+				p.InnermostString(ctxt.Bso)
+			}
+			fmt.Fprintln(ctxt.Bso)
+		}
+	}
+	for i := 0; i < len(s.P); i += 16 {
+		fmt.Fprintf(ctxt.Bso, "\t%#04x", uint(i))
+		j := i
+		for ; j < i+16 && j < len(s.P); j++ {
+			fmt.Fprintf(ctxt.Bso, " %02x", s.P[j])
+		}
+		for ; j < i+16; j++ {
+			fmt.Fprintf(ctxt.Bso, "   ")
+		}
+		fmt.Fprintf(ctxt.Bso, "  ")
+		for j = i; j < i+16 && j < len(s.P); j++ {
+			c := int(s.P[j])
+			b := byte('.')
+			if ' ' <= c && c <= 0x7e {
+				b = byte(c)
+			}
+			ctxt.Bso.WriteByte(b)
+		}
+
+		fmt.Fprintf(ctxt.Bso, "\n")
+	}
+
+	sort.Sort(relocByOff(s.R)) // generate stable output
+	for _, r := range s.R {
+		name := ""
+		ver := ""
+		if r.Sym != nil {
+			name = r.Sym.Name
+			if ctxt.Debugasm > 1 {
+				ver = fmt.Sprintf("<%d>", r.Sym.ABI())
+			}
+		} else if r.Type == objabi.R_TLS_LE {
+			name = "TLS"
+		}
+		if ctxt.Arch.InFamily(sys.ARM, sys.PPC64) {
+			fmt.Fprintf(ctxt.Bso, "\trel %d+%d t=%d %s%s+%x\n", int(r.Off), r.Siz, r.Type, name, ver, uint64(r.Add))
+		} else {
+			fmt.Fprintf(ctxt.Bso, "\trel %d+%d t=%d %s%s+%d\n", int(r.Off), r.Siz, r.Type, name, ver, r.Add)
+		}
+	}
+}
+
+// relocByOff sorts relocations by their offsets.
+type relocByOff []Reloc
+
+func (x relocByOff) Len() int           { return len(x) }
+func (x relocByOff) Less(i, j int) bool { return x[i].Off < x[j].Off }
+func (x relocByOff) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }