Adding upstream version 1.20.14.upstream/1.20.14upstream

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

8 files changed, 1770 insertions, 0 deletions

diff --git a/src/cmd/internal/objfile/disasm.go b/src/cmd/internal/objfile/disasm.go
new file mode 100644
index 0000000..c298d7e
--- /dev/null
+++ b/src/cmd/internal/objfile/disasm.go
@@ -0,0 +1,409 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package objfile
+
+import (
+	"bufio"
+	"bytes"
+	"container/list"
+	"debug/gosym"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+	"text/tabwriter"
+
+	"cmd/internal/src"
+
+	"golang.org/x/arch/arm/armasm"
+	"golang.org/x/arch/arm64/arm64asm"
+	"golang.org/x/arch/ppc64/ppc64asm"
+	"golang.org/x/arch/x86/x86asm"
+)
+
+// Disasm is a disassembler for a given File.
+type Disasm struct {
+	syms      []Sym            //symbols in file, sorted by address
+	pcln      Liner            // pcln table
+	text      []byte           // bytes of text segment (actual instructions)
+	textStart uint64           // start PC of text
+	textEnd   uint64           // end PC of text
+	goarch    string           // GOARCH string
+	disasm    disasmFunc       // disassembler function for goarch
+	byteOrder binary.ByteOrder // byte order for goarch
+}
+
+// Disasm returns a disassembler for the file f.
+func (e *Entry) Disasm() (*Disasm, error) {
+	syms, err := e.Symbols()
+	if err != nil {
+		return nil, err
+	}
+
+	pcln, err := e.PCLineTable()
+	if err != nil {
+		return nil, err
+	}
+
+	textStart, textBytes, err := e.Text()
+	if err != nil {
+		return nil, err
+	}
+
+	goarch := e.GOARCH()
+	disasm := disasms[goarch]
+	byteOrder := byteOrders[goarch]
+	if disasm == nil || byteOrder == nil {
+		return nil, fmt.Errorf("unsupported architecture")
+	}
+
+	// Filter out section symbols, overwriting syms in place.
+	keep := syms[:0]
+	for _, sym := range syms {
+		switch sym.Name {
+		case "runtime.text", "text", "_text", "runtime.etext", "etext", "_etext":
+			// drop
+		default:
+			keep = append(keep, sym)
+		}
+	}
+	syms = keep
+	d := &Disasm{
+		syms:      syms,
+		pcln:      pcln,
+		text:      textBytes,
+		textStart: textStart,
+		textEnd:   textStart + uint64(len(textBytes)),
+		goarch:    goarch,
+		disasm:    disasm,
+		byteOrder: byteOrder,
+	}
+
+	return d, nil
+}
+
+// lookup finds the symbol name containing addr.
+func (d *Disasm) lookup(addr uint64) (name string, base uint64) {
+	i := sort.Search(len(d.syms), func(i int) bool { return addr < d.syms[i].Addr })
+	if i > 0 {
+		s := d.syms[i-1]
+		if s.Addr != 0 && s.Addr <= addr && addr < s.Addr+uint64(s.Size) {
+			return s.Name, s.Addr
+		}
+	}
+	return "", 0
+}
+
+// base returns the final element in the path.
+// It works on both Windows and Unix paths,
+// regardless of host operating system.
+func base(path string) string {
+	path = path[strings.LastIndex(path, "/")+1:]
+	path = path[strings.LastIndex(path, `\`)+1:]
+	return path
+}
+
+// CachedFile contains the content of a file split into lines.
+type CachedFile struct {
+	FileName string
+	Lines    [][]byte
+}
+
+// FileCache is a simple LRU cache of file contents.
+type FileCache struct {
+	files  *list.List
+	maxLen int
+}
+
+// NewFileCache returns a FileCache which can contain up to maxLen cached file contents.
+func NewFileCache(maxLen int) *FileCache {
+	return &FileCache{
+		files:  list.New(),
+		maxLen: maxLen,
+	}
+}
+
+// Line returns the source code line for the given file and line number.
+// If the file is not already cached, reads it, inserts it into the cache,
+// and removes the least recently used file if necessary.
+// If the file is in cache, it is moved to the front of the list.
+func (fc *FileCache) Line(filename string, line int) ([]byte, error) {
+	if filepath.Ext(filename) != ".go" {
+		return nil, nil
+	}
+
+	// Clean filenames returned by src.Pos.SymFilename()
+	// or src.PosBase.SymFilename() removing
+	// the leading src.FileSymPrefix.
+	filename = strings.TrimPrefix(filename, src.FileSymPrefix)
+
+	// Expand literal "$GOROOT" rewritten by obj.AbsFile()
+	filename = filepath.Clean(os.ExpandEnv(filename))
+
+	var cf *CachedFile
+	var e *list.Element
+
+	for e = fc.files.Front(); e != nil; e = e.Next() {
+		cf = e.Value.(*CachedFile)
+		if cf.FileName == filename {
+			break
+		}
+	}
+
+	if e == nil {
+		content, err := os.ReadFile(filename)
+		if err != nil {
+			return nil, err
+		}
+
+		cf = &CachedFile{
+			FileName: filename,
+			Lines:    bytes.Split(content, []byte{'\n'}),
+		}
+		fc.files.PushFront(cf)
+
+		if fc.files.Len() >= fc.maxLen {
+			fc.files.Remove(fc.files.Back())
+		}
+	} else {
+		fc.files.MoveToFront(e)
+	}
+
+	// because //line directives can be out-of-range. (#36683)
+	if line-1 >= len(cf.Lines) || line-1 < 0 {
+		return nil, nil
+	}
+
+	return cf.Lines[line-1], nil
+}
+
+// Print prints a disassembly of the file to w.
+// If filter is non-nil, the disassembly only includes functions with names matching filter.
+// If printCode is true, the disassembly includs corresponding source lines.
+// The disassembly only includes functions that overlap the range [start, end).
+func (d *Disasm) Print(w io.Writer, filter *regexp.Regexp, start, end uint64, printCode bool, gnuAsm bool) {
+	if start < d.textStart {
+		start = d.textStart
+	}
+	if end > d.textEnd {
+		end = d.textEnd
+	}
+	printed := false
+	bw := bufio.NewWriter(w)
+
+	var fc *FileCache
+	if printCode {
+		fc = NewFileCache(8)
+	}
+
+	tw := tabwriter.NewWriter(bw, 18, 8, 1, '\t', tabwriter.StripEscape)
+	for _, sym := range d.syms {
+		symStart := sym.Addr
+		symEnd := sym.Addr + uint64(sym.Size)
+		relocs := sym.Relocs
+		if sym.Code != 'T' && sym.Code != 't' ||
+			symStart < d.textStart ||
+			symEnd <= start || end <= symStart ||
+			filter != nil && !filter.MatchString(sym.Name) {
+			continue
+		}
+		if printed {
+			fmt.Fprintf(bw, "\n")
+		}
+		printed = true
+
+		file, _, _ := d.pcln.PCToLine(sym.Addr)
+		fmt.Fprintf(bw, "TEXT %s(SB) %s\n", sym.Name, file)
+
+		if symEnd > end {
+			symEnd = end
+		}
+		code := d.text[:end-d.textStart]
+
+		var lastFile string
+		var lastLine int
+
+		d.Decode(symStart, symEnd, relocs, gnuAsm, func(pc, size uint64, file string, line int, text string) {
+			i := pc - d.textStart
+
+			if printCode {
+				if file != lastFile || line != lastLine {
+					if srcLine, err := fc.Line(file, line); err == nil {
+						fmt.Fprintf(tw, "%s%s%s\n", []byte{tabwriter.Escape}, srcLine, []byte{tabwriter.Escape})
+					}
+
+					lastFile, lastLine = file, line
+				}
+
+				fmt.Fprintf(tw, "  %#x\t", pc)
+			} else {
+				fmt.Fprintf(tw, "  %s:%d\t%#x\t", base(file), line, pc)
+			}
+
+			if size%4 != 0 || d.goarch == "386" || d.goarch == "amd64" {
+				// Print instruction as bytes.
+				fmt.Fprintf(tw, "%x", code[i:i+size])
+			} else {
+				// Print instruction as 32-bit words.
+				for j := uint64(0); j < size; j += 4 {
+					if j > 0 {
+						fmt.Fprintf(tw, " ")
+					}
+					fmt.Fprintf(tw, "%08x", d.byteOrder.Uint32(code[i+j:]))
+				}
+			}
+			fmt.Fprintf(tw, "\t%s\t\n", text)
+		})
+		tw.Flush()
+	}
+	bw.Flush()
+}
+
+// Decode disassembles the text segment range [start, end), calling f for each instruction.
+func (d *Disasm) Decode(start, end uint64, relocs []Reloc, gnuAsm bool, f func(pc, size uint64, file string, line int, text string)) {
+	if start < d.textStart {
+		start = d.textStart
+	}
+	if end > d.textEnd {
+		end = d.textEnd
+	}
+	code := d.text[:end-d.textStart]
+	lookup := d.lookup
+	for pc := start; pc < end; {
+		i := pc - d.textStart
+		text, size := d.disasm(code[i:], pc, lookup, d.byteOrder, gnuAsm)
+		file, line, _ := d.pcln.PCToLine(pc)
+		sep := "\t"
+		for len(relocs) > 0 && relocs[0].Addr < i+uint64(size) {
+			text += sep + relocs[0].Stringer.String(pc-start)
+			sep = " "
+			relocs = relocs[1:]
+		}
+		f(pc, uint64(size), file, line, text)
+		pc += uint64(size)
+	}
+}
+
+type lookupFunc = func(addr uint64) (sym string, base uint64)
+type disasmFunc func(code []byte, pc uint64, lookup lookupFunc, ord binary.ByteOrder, _ bool) (text string, size int)
+
+func disasm_386(code []byte, pc uint64, lookup lookupFunc, _ binary.ByteOrder, gnuAsm bool) (string, int) {
+	return disasm_x86(code, pc, lookup, 32, gnuAsm)
+}
+
+func disasm_amd64(code []byte, pc uint64, lookup lookupFunc, _ binary.ByteOrder, gnuAsm bool) (string, int) {
+	return disasm_x86(code, pc, lookup, 64, gnuAsm)
+}
+
+func disasm_x86(code []byte, pc uint64, lookup lookupFunc, arch int, gnuAsm bool) (string, int) {
+	inst, err := x86asm.Decode(code, arch)
+	var text string
+	size := inst.Len
+	if err != nil || size == 0 || inst.Op == 0 {
+		size = 1
+		text = "?"
+	} else {
+		if gnuAsm {
+			text = fmt.Sprintf("%-36s // %s", x86asm.GoSyntax(inst, pc, lookup), x86asm.GNUSyntax(inst, pc, nil))
+		} else {
+			text = x86asm.GoSyntax(inst, pc, lookup)
+		}
+	}
+	return text, size
+}
+
+type textReader struct {
+	code []byte
+	pc   uint64
+}
+
+func (r textReader) ReadAt(data []byte, off int64) (n int, err error) {
+	if off < 0 || uint64(off) < r.pc {
+		return 0, io.EOF
+	}
+	d := uint64(off) - r.pc
+	if d >= uint64(len(r.code)) {
+		return 0, io.EOF
+	}
+	n = copy(data, r.code[d:])
+	if n < len(data) {
+		err = io.ErrUnexpectedEOF
+	}
+	return
+}
+
+func disasm_arm(code []byte, pc uint64, lookup lookupFunc, _ binary.ByteOrder, gnuAsm bool) (string, int) {
+	inst, err := armasm.Decode(code, armasm.ModeARM)
+	var text string
+	size := inst.Len
+	if err != nil || size == 0 || inst.Op == 0 {
+		size = 4
+		text = "?"
+	} else if gnuAsm {
+		text = fmt.Sprintf("%-36s // %s", armasm.GoSyntax(inst, pc, lookup, textReader{code, pc}), armasm.GNUSyntax(inst))
+	} else {
+		text = armasm.GoSyntax(inst, pc, lookup, textReader{code, pc})
+	}
+	return text, size
+}
+
+func disasm_arm64(code []byte, pc uint64, lookup lookupFunc, byteOrder binary.ByteOrder, gnuAsm bool) (string, int) {
+	inst, err := arm64asm.Decode(code)
+	var text string
+	if err != nil || inst.Op == 0 {
+		text = "?"
+	} else if gnuAsm {
+		text = fmt.Sprintf("%-36s // %s", arm64asm.GoSyntax(inst, pc, lookup, textReader{code, pc}), arm64asm.GNUSyntax(inst))
+	} else {
+		text = arm64asm.GoSyntax(inst, pc, lookup, textReader{code, pc})
+	}
+	return text, 4
+}
+
+func disasm_ppc64(code []byte, pc uint64, lookup lookupFunc, byteOrder binary.ByteOrder, gnuAsm bool) (string, int) {
+	inst, err := ppc64asm.Decode(code, byteOrder)
+	var text string
+	size := inst.Len
+	if err != nil || size == 0 {
+		size = 4
+		text = "?"
+	} else {
+		if gnuAsm {
+			text = fmt.Sprintf("%-36s // %s", ppc64asm.GoSyntax(inst, pc, lookup), ppc64asm.GNUSyntax(inst, pc))
+		} else {
+			text = ppc64asm.GoSyntax(inst, pc, lookup)
+		}
+	}
+	return text, size
+}
+
+var disasms = map[string]disasmFunc{
+	"386":     disasm_386,
+	"amd64":   disasm_amd64,
+	"arm":     disasm_arm,
+	"arm64":   disasm_arm64,
+	"ppc64":   disasm_ppc64,
+	"ppc64le": disasm_ppc64,
+}
+
+var byteOrders = map[string]binary.ByteOrder{
+	"386":     binary.LittleEndian,
+	"amd64":   binary.LittleEndian,
+	"arm":     binary.LittleEndian,
+	"arm64":   binary.LittleEndian,
+	"ppc64":   binary.BigEndian,
+	"ppc64le": binary.LittleEndian,
+	"s390x":   binary.BigEndian,
+}
+
+type Liner interface {
+	// Given a pc, returns the corresponding file, line, and function data.
+	// If unknown, returns "",0,nil.
+	PCToLine(uint64) (string, int, *gosym.Func)
+}
diff --git a/src/cmd/internal/objfile/elf.go b/src/cmd/internal/objfile/elf.go
new file mode 100644
index 0000000..c64c254
--- /dev/null
+++ b/src/cmd/internal/objfile/elf.go
@@ -0,0 +1,177 @@
+// 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.
+
+// Parsing of ELF executables (Linux, FreeBSD, and so on).
+
+package objfile
+
+import (
+	"debug/dwarf"
+	"debug/elf"
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+type elfFile struct {
+	elf *elf.File
+}
+
+func openElf(r io.ReaderAt) (rawFile, error) {
+	f, err := elf.NewFile(r)
+	if err != nil {
+		return nil, err
+	}
+	return &elfFile{f}, nil
+}
+
+func (f *elfFile) symbols() ([]Sym, error) {
+	elfSyms, err := f.elf.Symbols()
+	if err != nil {
+		return nil, err
+	}
+
+	var syms []Sym
+	for _, s := range elfSyms {
+		sym := Sym{Addr: s.Value, Name: s.Name, Size: int64(s.Size), Code: '?'}
+		switch s.Section {
+		case elf.SHN_UNDEF:
+			sym.Code = 'U'
+		case elf.SHN_COMMON:
+			sym.Code = 'B'
+		default:
+			i := int(s.Section)
+			if i < 0 || i >= len(f.elf.Sections) {
+				break
+			}
+			sect := f.elf.Sections[i]
+			switch sect.Flags & (elf.SHF_WRITE | elf.SHF_ALLOC | elf.SHF_EXECINSTR) {
+			case elf.SHF_ALLOC | elf.SHF_EXECINSTR:
+				sym.Code = 'T'
+			case elf.SHF_ALLOC:
+				sym.Code = 'R'
+			case elf.SHF_ALLOC | elf.SHF_WRITE:
+				sym.Code = 'D'
+			}
+		}
+		if elf.ST_BIND(s.Info) == elf.STB_LOCAL {
+			sym.Code += 'a' - 'A'
+		}
+		syms = append(syms, sym)
+	}
+
+	return syms, nil
+}
+
+func (f *elfFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
+	if sect := f.elf.Section(".text"); sect != nil {
+		textStart = sect.Addr
+	}
+
+	sect := f.elf.Section(".gosymtab")
+	if sect == nil {
+		// try .data.rel.ro.gosymtab, for PIE binaries
+		sect = f.elf.Section(".data.rel.ro.gosymtab")
+	}
+	if sect != nil {
+		if symtab, err = sect.Data(); err != nil {
+			return 0, nil, nil, err
+		}
+	} else {
+		// if both sections failed, try the symbol
+		symtab = f.symbolData("runtime.symtab", "runtime.esymtab")
+	}
+
+	sect = f.elf.Section(".gopclntab")
+	if sect == nil {
+		// try .data.rel.ro.gopclntab, for PIE binaries
+		sect = f.elf.Section(".data.rel.ro.gopclntab")
+	}
+	if sect != nil {
+		if pclntab, err = sect.Data(); err != nil {
+			return 0, nil, nil, err
+		}
+	} else {
+		// if both sections failed, try the symbol
+		pclntab = f.symbolData("runtime.pclntab", "runtime.epclntab")
+	}
+
+	return textStart, symtab, pclntab, nil
+}
+
+func (f *elfFile) text() (textStart uint64, text []byte, err error) {
+	sect := f.elf.Section(".text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = sect.Addr
+	text, err = sect.Data()
+	return
+}
+
+func (f *elfFile) goarch() string {
+	switch f.elf.Machine {
+	case elf.EM_386:
+		return "386"
+	case elf.EM_X86_64:
+		return "amd64"
+	case elf.EM_ARM:
+		return "arm"
+	case elf.EM_AARCH64:
+		return "arm64"
+	case elf.EM_PPC64:
+		if f.elf.ByteOrder == binary.LittleEndian {
+			return "ppc64le"
+		}
+		return "ppc64"
+	case elf.EM_S390:
+		return "s390x"
+	}
+	return ""
+}
+
+func (f *elfFile) loadAddress() (uint64, error) {
+	for _, p := range f.elf.Progs {
+		if p.Type == elf.PT_LOAD && p.Flags&elf.PF_X != 0 {
+			return p.Vaddr, nil
+		}
+	}
+	return 0, fmt.Errorf("unknown load address")
+}
+
+func (f *elfFile) dwarf() (*dwarf.Data, error) {
+	return f.elf.DWARF()
+}
+
+func (f *elfFile) symbolData(start, end string) []byte {
+	elfSyms, err := f.elf.Symbols()
+	if err != nil {
+		return nil
+	}
+	var addr, eaddr uint64
+	for _, s := range elfSyms {
+		if s.Name == start {
+			addr = s.Value
+		} else if s.Name == end {
+			eaddr = s.Value
+		}
+		if addr != 0 && eaddr != 0 {
+			break
+		}
+	}
+	if addr == 0 || eaddr < addr {
+		return nil
+	}
+	size := eaddr - addr
+	data := make([]byte, size)
+	for _, prog := range f.elf.Progs {
+		if prog.Vaddr <= addr && addr+size-1 <= prog.Vaddr+prog.Filesz-1 {
+			if _, err := prog.ReadAt(data, int64(addr-prog.Vaddr)); err != nil {
+				return nil
+			}
+			return data
+		}
+	}
+	return nil
+}
diff --git a/src/cmd/internal/objfile/goobj.go b/src/cmd/internal/objfile/goobj.go
new file mode 100644
index 0000000..24d2d0b
--- /dev/null
+++ b/src/cmd/internal/objfile/goobj.go
@@ -0,0 +1,341 @@
+// 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.
+
+// Parsing of Go intermediate object files and archives.
+
+package objfile
+
+import (
+	"cmd/internal/archive"
+	"cmd/internal/goobj"
+	"cmd/internal/objabi"
+	"cmd/internal/sys"
+	"debug/dwarf"
+	"debug/gosym"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+type goobjFile struct {
+	goobj *archive.GoObj
+	r     *goobj.Reader
+	f     *os.File
+	arch  *sys.Arch
+}
+
+func openGoFile(f *os.File) (*File, error) {
+	a, err := archive.Parse(f, false)
+	if err != nil {
+		return nil, err
+	}
+	entries := make([]*Entry, 0, len(a.Entries))
+L:
+	for _, e := range a.Entries {
+		switch e.Type {
+		case archive.EntryPkgDef:
+			continue
+		case archive.EntryGoObj:
+			o := e.Obj
+			b := make([]byte, o.Size)
+			_, err := f.ReadAt(b, o.Offset)
+			if err != nil {
+				return nil, err
+			}
+			r := goobj.NewReaderFromBytes(b, false)
+			var arch *sys.Arch
+			for _, a := range sys.Archs {
+				if a.Name == e.Obj.Arch {
+					arch = a
+					break
+				}
+			}
+			entries = append(entries, &Entry{
+				name: e.Name,
+				raw:  &goobjFile{e.Obj, r, f, arch},
+			})
+			continue
+		case archive.EntryNativeObj:
+			nr := io.NewSectionReader(f, e.Offset, e.Size)
+			for _, try := range openers {
+				if raw, err := try(nr); err == nil {
+					entries = append(entries, &Entry{
+						name: e.Name,
+						raw:  raw,
+					})
+					continue L
+				}
+			}
+		}
+		return nil, fmt.Errorf("open %s: unrecognized archive member %s", f.Name(), e.Name)
+	}
+	return &File{f, entries}, nil
+}
+
+func goobjName(name string, ver int) string {
+	if ver == 0 {
+		return name
+	}
+	return fmt.Sprintf("%s<%d>", name, ver)
+}
+
+type goobjReloc struct {
+	Off  int32
+	Size uint8
+	Type objabi.RelocType
+	Add  int64
+	Sym  string
+}
+
+func (r goobjReloc) String(insnOffset uint64) string {
+	delta := int64(r.Off) - int64(insnOffset)
+	s := fmt.Sprintf("[%d:%d]%s", delta, delta+int64(r.Size), r.Type)
+	if r.Sym != "" {
+		if r.Add != 0 {
+			return fmt.Sprintf("%s:%s+%d", s, r.Sym, r.Add)
+		}
+		return fmt.Sprintf("%s:%s", s, r.Sym)
+	}
+	if r.Add != 0 {
+		return fmt.Sprintf("%s:%d", s, r.Add)
+	}
+	return s
+}
+
+func (f *goobjFile) symbols() ([]Sym, error) {
+	r := f.r
+	var syms []Sym
+
+	// Name of referenced indexed symbols.
+	nrefName := r.NRefName()
+	refNames := make(map[goobj.SymRef]string, nrefName)
+	for i := 0; i < nrefName; i++ {
+		rn := r.RefName(i)
+		refNames[rn.Sym()] = rn.Name(r)
+	}
+
+	abiToVer := func(abi uint16) int {
+		var ver int
+		if abi == goobj.SymABIstatic {
+			// Static symbol
+			ver = 1
+		}
+		return ver
+	}
+
+	resolveSymRef := func(s goobj.SymRef) string {
+		var i uint32
+		switch p := s.PkgIdx; p {
+		case goobj.PkgIdxInvalid:
+			if s.SymIdx != 0 {
+				panic("bad sym ref")
+			}
+			return ""
+		case goobj.PkgIdxHashed64:
+			i = s.SymIdx + uint32(r.NSym())
+		case goobj.PkgIdxHashed:
+			i = s.SymIdx + uint32(r.NSym()+r.NHashed64def())
+		case goobj.PkgIdxNone:
+			i = s.SymIdx + uint32(r.NSym()+r.NHashed64def()+r.NHasheddef())
+		case goobj.PkgIdxBuiltin:
+			name, abi := goobj.BuiltinName(int(s.SymIdx))
+			return goobjName(name, abi)
+		case goobj.PkgIdxSelf:
+			i = s.SymIdx
+		default:
+			return refNames[s]
+		}
+		sym := r.Sym(i)
+		return goobjName(sym.Name(r), abiToVer(sym.ABI()))
+	}
+
+	// Defined symbols
+	ndef := uint32(r.NSym() + r.NHashed64def() + r.NHasheddef() + r.NNonpkgdef())
+	for i := uint32(0); i < ndef; i++ {
+		osym := r.Sym(i)
+		if osym.Name(r) == "" {
+			continue // not a real symbol
+		}
+		name := osym.Name(r)
+		ver := osym.ABI()
+		name = goobjName(name, abiToVer(ver))
+		typ := objabi.SymKind(osym.Type())
+		var code rune = '?'
+		switch typ {
+		case objabi.STEXT:
+			code = 'T'
+		case objabi.SRODATA:
+			code = 'R'
+		case objabi.SNOPTRDATA, objabi.SDATA:
+			code = 'D'
+		case objabi.SBSS, objabi.SNOPTRBSS, objabi.STLSBSS:
+			code = 'B'
+		}
+		if ver >= goobj.SymABIstatic {
+			code += 'a' - 'A'
+		}
+
+		sym := Sym{
+			Name: name,
+			Addr: uint64(r.DataOff(i)),
+			Size: int64(osym.Siz()),
+			Code: code,
+		}
+
+		relocs := r.Relocs(i)
+		sym.Relocs = make([]Reloc, len(relocs))
+		for j := range relocs {
+			rel := &relocs[j]
+			sym.Relocs[j] = Reloc{
+				Addr: uint64(r.DataOff(i)) + uint64(rel.Off()),
+				Size: uint64(rel.Siz()),
+				Stringer: goobjReloc{
+					Off:  rel.Off(),
+					Size: rel.Siz(),
+					Type: objabi.RelocType(rel.Type()),
+					Add:  rel.Add(),
+					Sym:  resolveSymRef(rel.Sym()),
+				},
+			}
+		}
+
+		syms = append(syms, sym)
+	}
+
+	// Referenced symbols
+	n := ndef + uint32(r.NNonpkgref())
+	for i := ndef; i < n; i++ {
+		osym := r.Sym(i)
+		sym := Sym{Name: osym.Name(r), Code: 'U'}
+		syms = append(syms, sym)
+	}
+	for i := 0; i < nrefName; i++ {
+		rn := r.RefName(i)
+		sym := Sym{Name: rn.Name(r), Code: 'U'}
+		syms = append(syms, sym)
+	}
+
+	return syms, nil
+}
+
+func (f *goobjFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
+	// Should never be called. We implement Liner below, callers
+	// should use that instead.
+	return 0, nil, nil, fmt.Errorf("pcln not available in go object file")
+}
+
+// Find returns the file name, line, and function data for the given pc.
+// Returns "",0,nil if unknown.
+// This function implements the Liner interface in preference to pcln() above.
+func (f *goobjFile) PCToLine(pc uint64) (string, int, *gosym.Func) {
+	r := f.r
+	if f.arch == nil {
+		return "", 0, nil
+	}
+	getSymData := func(s goobj.SymRef) []byte {
+		if s.PkgIdx != goobj.PkgIdxHashed {
+			// We don't need the data for non-hashed symbols, yet.
+			panic("not supported")
+		}
+		i := uint32(s.SymIdx + uint32(r.NSym()+r.NHashed64def()))
+		return r.BytesAt(r.DataOff(i), r.DataSize(i))
+	}
+
+	ndef := uint32(r.NSym() + r.NHashed64def() + r.NHasheddef() + r.NNonpkgdef())
+	for i := uint32(0); i < ndef; i++ {
+		osym := r.Sym(i)
+		addr := uint64(r.DataOff(i))
+		if pc < addr || pc >= addr+uint64(osym.Siz()) {
+			continue
+		}
+		var pcfileSym, pclineSym goobj.SymRef
+		for _, a := range r.Auxs(i) {
+			switch a.Type() {
+			case goobj.AuxPcfile:
+				pcfileSym = a.Sym()
+			case goobj.AuxPcline:
+				pclineSym = a.Sym()
+			}
+		}
+		if pcfileSym.IsZero() || pclineSym.IsZero() {
+			continue
+		}
+		pcline := getSymData(pclineSym)
+		line := int(pcValue(pcline, pc-addr, f.arch))
+		pcfile := getSymData(pcfileSym)
+		fileID := pcValue(pcfile, pc-addr, f.arch)
+		fileName := r.File(int(fileID))
+		// Note: we provide only the name in the Func structure.
+		// We could provide more if needed.
+		return fileName, line, &gosym.Func{Sym: &gosym.Sym{Name: osym.Name(r)}}
+	}
+	return "", 0, nil
+}
+
+// pcValue looks up the given PC in a pc value table. target is the
+// offset of the pc from the entry point.
+func pcValue(tab []byte, target uint64, arch *sys.Arch) int32 {
+	val := int32(-1)
+	var pc uint64
+	for step(&tab, &pc, &val, pc == 0, arch) {
+		if target < pc {
+			return val
+		}
+	}
+	return -1
+}
+
+// step advances to the next pc, value pair in the encoded table.
+func step(p *[]byte, pc *uint64, val *int32, first bool, arch *sys.Arch) bool {
+	uvdelta := readvarint(p)
+	if uvdelta == 0 && !first {
+		return false
+	}
+	if uvdelta&1 != 0 {
+		uvdelta = ^(uvdelta >> 1)
+	} else {
+		uvdelta >>= 1
+	}
+	vdelta := int32(uvdelta)
+	pcdelta := readvarint(p) * uint32(arch.MinLC)
+	*pc += uint64(pcdelta)
+	*val += vdelta
+	return true
+}
+
+// readvarint reads, removes, and returns a varint from *p.
+func readvarint(p *[]byte) uint32 {
+	var v, shift uint32
+	s := *p
+	for shift = 0; ; shift += 7 {
+		b := s[0]
+		s = s[1:]
+		v |= (uint32(b) & 0x7F) << shift
+		if b&0x80 == 0 {
+			break
+		}
+	}
+	*p = s
+	return v
+}
+
+// We treat the whole object file as the text section.
+func (f *goobjFile) text() (textStart uint64, text []byte, err error) {
+	text = make([]byte, f.goobj.Size)
+	_, err = f.f.ReadAt(text, int64(f.goobj.Offset))
+	return
+}
+
+func (f *goobjFile) goarch() string {
+	return f.goobj.Arch
+}
+
+func (f *goobjFile) loadAddress() (uint64, error) {
+	return 0, fmt.Errorf("unknown load address")
+}
+
+func (f *goobjFile) dwarf() (*dwarf.Data, error) {
+	return nil, errors.New("no DWARF data in go object file")
+}
diff --git a/src/cmd/internal/objfile/macho.go b/src/cmd/internal/objfile/macho.go
new file mode 100644
index 0000000..1d6963f
--- /dev/null
+++ b/src/cmd/internal/objfile/macho.go
@@ -0,0 +1,136 @@
+// 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.
+
+// Parsing of Mach-O executables (OS X).
+
+package objfile
+
+import (
+	"debug/dwarf"
+	"debug/macho"
+	"fmt"
+	"io"
+	"sort"
+)
+
+const stabTypeMask = 0xe0
+
+type machoFile struct {
+	macho *macho.File
+}
+
+func openMacho(r io.ReaderAt) (rawFile, error) {
+	f, err := macho.NewFile(r)
+	if err != nil {
+		return nil, err
+	}
+	return &machoFile{f}, nil
+}
+
+func (f *machoFile) symbols() ([]Sym, error) {
+	if f.macho.Symtab == nil {
+		return nil, nil
+	}
+
+	// Build sorted list of addresses of all symbols.
+	// We infer the size of a symbol by looking at where the next symbol begins.
+	var addrs []uint64
+	for _, s := range f.macho.Symtab.Syms {
+		// Skip stab debug info.
+		if s.Type&stabTypeMask == 0 {
+			addrs = append(addrs, s.Value)
+		}
+	}
+	sort.Sort(uint64s(addrs))
+
+	var syms []Sym
+	for _, s := range f.macho.Symtab.Syms {
+		if s.Type&stabTypeMask != 0 {
+			// Skip stab debug info.
+			continue
+		}
+		sym := Sym{Name: s.Name, Addr: s.Value, Code: '?'}
+		i := sort.Search(len(addrs), func(x int) bool { return addrs[x] > s.Value })
+		if i < len(addrs) {
+			sym.Size = int64(addrs[i] - s.Value)
+		}
+		if s.Sect == 0 {
+			sym.Code = 'U'
+		} else if int(s.Sect) <= len(f.macho.Sections) {
+			sect := f.macho.Sections[s.Sect-1]
+			switch sect.Seg {
+			case "__TEXT", "__DATA_CONST":
+				sym.Code = 'R'
+			case "__DATA":
+				sym.Code = 'D'
+			}
+			switch sect.Seg + " " + sect.Name {
+			case "__TEXT __text":
+				sym.Code = 'T'
+			case "__DATA __bss", "__DATA __noptrbss":
+				sym.Code = 'B'
+			}
+		}
+		syms = append(syms, sym)
+	}
+
+	return syms, nil
+}
+
+func (f *machoFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
+	if sect := f.macho.Section("__text"); sect != nil {
+		textStart = sect.Addr
+	}
+	if sect := f.macho.Section("__gosymtab"); sect != nil {
+		if symtab, err = sect.Data(); err != nil {
+			return 0, nil, nil, err
+		}
+	}
+	if sect := f.macho.Section("__gopclntab"); sect != nil {
+		if pclntab, err = sect.Data(); err != nil {
+			return 0, nil, nil, err
+		}
+	}
+	return textStart, symtab, pclntab, nil
+}
+
+func (f *machoFile) text() (textStart uint64, text []byte, err error) {
+	sect := f.macho.Section("__text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = sect.Addr
+	text, err = sect.Data()
+	return
+}
+
+func (f *machoFile) goarch() string {
+	switch f.macho.Cpu {
+	case macho.Cpu386:
+		return "386"
+	case macho.CpuAmd64:
+		return "amd64"
+	case macho.CpuArm:
+		return "arm"
+	case macho.CpuArm64:
+		return "arm64"
+	case macho.CpuPpc64:
+		return "ppc64"
+	}
+	return ""
+}
+
+type uint64s []uint64
+
+func (x uint64s) Len() int           { return len(x) }
+func (x uint64s) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
+func (x uint64s) Less(i, j int) bool { return x[i] < x[j] }
+
+func (f *machoFile) loadAddress() (uint64, error) {
+	return 0, fmt.Errorf("unknown load address")
+}
+
+func (f *machoFile) dwarf() (*dwarf.Data, error) {
+	return f.macho.DWARF()
+}
diff --git a/src/cmd/internal/objfile/objfile.go b/src/cmd/internal/objfile/objfile.go
new file mode 100644
index 0000000..d890a0b
--- /dev/null
+++ b/src/cmd/internal/objfile/objfile.go
@@ -0,0 +1,186 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package objfile implements portable access to OS-specific executable files.
+package objfile
+
+import (
+	"cmd/internal/archive"
+	"debug/dwarf"
+	"debug/gosym"
+	"fmt"
+	"io"
+	"os"
+	"sort"
+)
+
+type rawFile interface {
+	symbols() (syms []Sym, err error)
+	pcln() (textStart uint64, symtab, pclntab []byte, err error)
+	text() (textStart uint64, text []byte, err error)
+	goarch() string
+	loadAddress() (uint64, error)
+	dwarf() (*dwarf.Data, error)
+}
+
+// A File is an opened executable file.
+type File struct {
+	r       *os.File
+	entries []*Entry
+}
+
+type Entry struct {
+	name string
+	raw  rawFile
+}
+
+// A Sym is a symbol defined in an executable file.
+type Sym struct {
+	Name   string  // symbol name
+	Addr   uint64  // virtual address of symbol
+	Size   int64   // size in bytes
+	Code   rune    // nm code (T for text, D for data, and so on)
+	Type   string  // XXX?
+	Relocs []Reloc // in increasing Addr order
+}
+
+type Reloc struct {
+	Addr     uint64 // Address of first byte that reloc applies to.
+	Size     uint64 // Number of bytes
+	Stringer RelocStringer
+}
+
+type RelocStringer interface {
+	// insnOffset is the offset of the instruction containing the relocation
+	// from the start of the symbol containing the relocation.
+	String(insnOffset uint64) string
+}
+
+var openers = []func(io.ReaderAt) (rawFile, error){
+	openElf,
+	openMacho,
+	openPE,
+	openPlan9,
+	openXcoff,
+}
+
+// Open opens the named file.
+// The caller must call f.Close when the file is no longer needed.
+func Open(name string) (*File, error) {
+	r, err := os.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	if f, err := openGoFile(r); err == nil {
+		return f, nil
+	} else if _, ok := err.(archive.ErrGoObjOtherVersion); ok {
+		return nil, fmt.Errorf("open %s: %v", name, err)
+	}
+	for _, try := range openers {
+		if raw, err := try(r); err == nil {
+			return &File{r, []*Entry{{raw: raw}}}, nil
+		}
+	}
+	r.Close()
+	return nil, fmt.Errorf("open %s: unrecognized object file", name)
+}
+
+func (f *File) Close() error {
+	return f.r.Close()
+}
+
+func (f *File) Entries() []*Entry {
+	return f.entries
+}
+
+func (f *File) Symbols() ([]Sym, error) {
+	return f.entries[0].Symbols()
+}
+
+func (f *File) PCLineTable() (Liner, error) {
+	return f.entries[0].PCLineTable()
+}
+
+func (f *File) Text() (uint64, []byte, error) {
+	return f.entries[0].Text()
+}
+
+func (f *File) GOARCH() string {
+	return f.entries[0].GOARCH()
+}
+
+func (f *File) LoadAddress() (uint64, error) {
+	return f.entries[0].LoadAddress()
+}
+
+func (f *File) DWARF() (*dwarf.Data, error) {
+	return f.entries[0].DWARF()
+}
+
+func (f *File) Disasm() (*Disasm, error) {
+	return f.entries[0].Disasm()
+}
+
+func (e *Entry) Name() string {
+	return e.name
+}
+
+func (e *Entry) Symbols() ([]Sym, error) {
+	syms, err := e.raw.symbols()
+	if err != nil {
+		return nil, err
+	}
+	sort.Sort(byAddr(syms))
+	return syms, nil
+}
+
+type byAddr []Sym
+
+func (x byAddr) Less(i, j int) bool { return x[i].Addr < x[j].Addr }
+func (x byAddr) Len() int           { return len(x) }
+func (x byAddr) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
+
+func (e *Entry) PCLineTable() (Liner, error) {
+	// If the raw file implements Liner directly, use that.
+	// Currently, only Go intermediate objects and archives (goobj) use this path.
+	if pcln, ok := e.raw.(Liner); ok {
+		return pcln, nil
+	}
+	// Otherwise, read the pcln tables and build a Liner out of that.
+	textStart, symtab, pclntab, err := e.raw.pcln()
+	if err != nil {
+		return nil, err
+	}
+	syms, err := e.raw.symbols()
+	if err == nil {
+		for _, s := range syms {
+			if s.Name == "runtime.text" {
+				textStart = s.Addr
+				break
+			}
+		}
+	}
+	return gosym.NewTable(symtab, gosym.NewLineTable(pclntab, textStart))
+}
+
+func (e *Entry) Text() (uint64, []byte, error) {
+	return e.raw.text()
+}
+
+func (e *Entry) GOARCH() string {
+	return e.raw.goarch()
+}
+
+// LoadAddress returns the expected load address of the file.
+// This differs from the actual load address for a position-independent
+// executable.
+func (e *Entry) LoadAddress() (uint64, error) {
+	return e.raw.loadAddress()
+}
+
+// DWARF returns DWARF debug data for the file, if any.
+// This is for cmd/pprof to locate cgo functions.
+func (e *Entry) DWARF() (*dwarf.Data, error) {
+	return e.raw.dwarf()
+}
diff --git a/src/cmd/internal/objfile/pe.go b/src/cmd/internal/objfile/pe.go
new file mode 100644
index 0000000..4c4be1e
--- /dev/null
+++ b/src/cmd/internal/objfile/pe.go
@@ -0,0 +1,202 @@
+// 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.
+
+// Parsing of PE executables (Microsoft Windows).
+
+package objfile
+
+import (
+	"debug/dwarf"
+	"debug/pe"
+	"fmt"
+	"io"
+	"sort"
+)
+
+type peFile struct {
+	pe *pe.File
+}
+
+func openPE(r io.ReaderAt) (rawFile, error) {
+	f, err := pe.NewFile(r)
+	if err != nil {
+		return nil, err
+	}
+	return &peFile{f}, nil
+}
+
+func (f *peFile) symbols() ([]Sym, error) {
+	// Build sorted list of addresses of all symbols.
+	// We infer the size of a symbol by looking at where the next symbol begins.
+	var addrs []uint64
+
+	imageBase, _ := f.imageBase()
+
+	var syms []Sym
+	for _, s := range f.pe.Symbols {
+		const (
+			N_UNDEF = 0  // An undefined (extern) symbol
+			N_ABS   = -1 // An absolute symbol (e_value is a constant, not an address)
+			N_DEBUG = -2 // A debugging symbol
+		)
+		sym := Sym{Name: s.Name, Addr: uint64(s.Value), Code: '?'}
+		switch s.SectionNumber {
+		case N_UNDEF:
+			sym.Code = 'U'
+		case N_ABS:
+			sym.Code = 'C'
+		case N_DEBUG:
+			sym.Code = '?'
+		default:
+			if s.SectionNumber < 0 || len(f.pe.Sections) < int(s.SectionNumber) {
+				return nil, fmt.Errorf("invalid section number in symbol table")
+			}
+			sect := f.pe.Sections[s.SectionNumber-1]
+			const (
+				text  = 0x20
+				data  = 0x40
+				bss   = 0x80
+				permW = 0x80000000
+			)
+			ch := sect.Characteristics
+			switch {
+			case ch&text != 0:
+				sym.Code = 'T'
+			case ch&data != 0:
+				if ch&permW == 0 {
+					sym.Code = 'R'
+				} else {
+					sym.Code = 'D'
+				}
+			case ch&bss != 0:
+				sym.Code = 'B'
+			}
+			sym.Addr += imageBase + uint64(sect.VirtualAddress)
+		}
+		syms = append(syms, sym)
+		addrs = append(addrs, sym.Addr)
+	}
+
+	sort.Sort(uint64s(addrs))
+	for i := range syms {
+		j := sort.Search(len(addrs), func(x int) bool { return addrs[x] > syms[i].Addr })
+		if j < len(addrs) {
+			syms[i].Size = int64(addrs[j] - syms[i].Addr)
+		}
+	}
+
+	return syms, nil
+}
+
+func (f *peFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
+	imageBase, err := f.imageBase()
+	if err != nil {
+		return 0, nil, nil, err
+	}
+
+	if sect := f.pe.Section(".text"); sect != nil {
+		textStart = imageBase + uint64(sect.VirtualAddress)
+	}
+	if pclntab, err = loadPETable(f.pe, "runtime.pclntab", "runtime.epclntab"); err != nil {
+		// We didn't find the symbols, so look for the names used in 1.3 and earlier.
+		// TODO: Remove code looking for the old symbols when we no longer care about 1.3.
+		var err2 error
+		if pclntab, err2 = loadPETable(f.pe, "pclntab", "epclntab"); err2 != nil {
+			return 0, nil, nil, err
+		}
+	}
+	if symtab, err = loadPETable(f.pe, "runtime.symtab", "runtime.esymtab"); err != nil {
+		// Same as above.
+		var err2 error
+		if symtab, err2 = loadPETable(f.pe, "symtab", "esymtab"); err2 != nil {
+			return 0, nil, nil, err
+		}
+	}
+	return textStart, symtab, pclntab, nil
+}
+
+func (f *peFile) text() (textStart uint64, text []byte, err error) {
+	imageBase, err := f.imageBase()
+	if err != nil {
+		return 0, nil, err
+	}
+
+	sect := f.pe.Section(".text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = imageBase + uint64(sect.VirtualAddress)
+	text, err = sect.Data()
+	return
+}
+
+func findPESymbol(f *pe.File, name string) (*pe.Symbol, error) {
+	for _, s := range f.Symbols {
+		if s.Name != name {
+			continue
+		}
+		if s.SectionNumber <= 0 {
+			return nil, fmt.Errorf("symbol %s: invalid section number %d", name, s.SectionNumber)
+		}
+		if len(f.Sections) < int(s.SectionNumber) {
+			return nil, fmt.Errorf("symbol %s: section number %d is larger than max %d", name, s.SectionNumber, len(f.Sections))
+		}
+		return s, nil
+	}
+	return nil, fmt.Errorf("no %s symbol found", name)
+}
+
+func loadPETable(f *pe.File, sname, ename string) ([]byte, error) {
+	ssym, err := findPESymbol(f, sname)
+	if err != nil {
+		return nil, err
+	}
+	esym, err := findPESymbol(f, ename)
+	if err != nil {
+		return nil, err
+	}
+	if ssym.SectionNumber != esym.SectionNumber {
+		return nil, fmt.Errorf("%s and %s symbols must be in the same section", sname, ename)
+	}
+	sect := f.Sections[ssym.SectionNumber-1]
+	data, err := sect.Data()
+	if err != nil {
+		return nil, err
+	}
+	return data[ssym.Value:esym.Value], nil
+}
+
+func (f *peFile) goarch() string {
+	switch f.pe.Machine {
+	case pe.IMAGE_FILE_MACHINE_I386:
+		return "386"
+	case pe.IMAGE_FILE_MACHINE_AMD64:
+		return "amd64"
+	case pe.IMAGE_FILE_MACHINE_ARMNT:
+		return "arm"
+	case pe.IMAGE_FILE_MACHINE_ARM64:
+		return "arm64"
+	default:
+		return ""
+	}
+}
+
+func (f *peFile) loadAddress() (uint64, error) {
+	return f.imageBase()
+}
+
+func (f *peFile) imageBase() (uint64, error) {
+	switch oh := f.pe.OptionalHeader.(type) {
+	case *pe.OptionalHeader32:
+		return uint64(oh.ImageBase), nil
+	case *pe.OptionalHeader64:
+		return oh.ImageBase, nil
+	default:
+		return 0, fmt.Errorf("pe file format not recognized")
+	}
+}
+
+func (f *peFile) dwarf() (*dwarf.Data, error) {
+	return f.pe.DWARF()
+}
diff --git a/src/cmd/internal/objfile/plan9obj.go b/src/cmd/internal/objfile/plan9obj.go
new file mode 100644
index 0000000..da0b345
--- /dev/null
+++ b/src/cmd/internal/objfile/plan9obj.go
@@ -0,0 +1,156 @@
+// Copyright 2014 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.
+
+// Parsing of Plan 9 a.out executables.
+
+package objfile
+
+import (
+	"debug/dwarf"
+	"debug/plan9obj"
+	"errors"
+	"fmt"
+	"io"
+	"sort"
+)
+
+var validSymType = map[rune]bool{
+	'T': true,
+	't': true,
+	'D': true,
+	'd': true,
+	'B': true,
+	'b': true,
+}
+
+type plan9File struct {
+	plan9 *plan9obj.File
+}
+
+func openPlan9(r io.ReaderAt) (rawFile, error) {
+	f, err := plan9obj.NewFile(r)
+	if err != nil {
+		return nil, err
+	}
+	return &plan9File{f}, nil
+}
+
+func (f *plan9File) symbols() ([]Sym, error) {
+	plan9Syms, err := f.plan9.Symbols()
+	if err != nil {
+		return nil, err
+	}
+
+	// Build sorted list of addresses of all symbols.
+	// We infer the size of a symbol by looking at where the next symbol begins.
+	var addrs []uint64
+	for _, s := range plan9Syms {
+		if !validSymType[s.Type] {
+			continue
+		}
+		addrs = append(addrs, s.Value)
+	}
+	sort.Sort(uint64s(addrs))
+
+	var syms []Sym
+
+	for _, s := range plan9Syms {
+		if !validSymType[s.Type] {
+			continue
+		}
+		sym := Sym{Addr: s.Value, Name: s.Name, Code: s.Type}
+		i := sort.Search(len(addrs), func(x int) bool { return addrs[x] > s.Value })
+		if i < len(addrs) {
+			sym.Size = int64(addrs[i] - s.Value)
+		}
+		syms = append(syms, sym)
+	}
+
+	return syms, nil
+}
+
+func (f *plan9File) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
+	textStart = f.plan9.LoadAddress + f.plan9.HdrSize
+	if pclntab, err = loadPlan9Table(f.plan9, "runtime.pclntab", "runtime.epclntab"); err != nil {
+		// We didn't find the symbols, so look for the names used in 1.3 and earlier.
+		// TODO: Remove code looking for the old symbols when we no longer care about 1.3.
+		var err2 error
+		if pclntab, err2 = loadPlan9Table(f.plan9, "pclntab", "epclntab"); err2 != nil {
+			return 0, nil, nil, err
+		}
+	}
+	if symtab, err = loadPlan9Table(f.plan9, "runtime.symtab", "runtime.esymtab"); err != nil {
+		// Same as above.
+		var err2 error
+		if symtab, err2 = loadPlan9Table(f.plan9, "symtab", "esymtab"); err2 != nil {
+			return 0, nil, nil, err
+		}
+	}
+	return textStart, symtab, pclntab, nil
+}
+
+func (f *plan9File) text() (textStart uint64, text []byte, err error) {
+	sect := f.plan9.Section("text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = f.plan9.LoadAddress + f.plan9.HdrSize
+	text, err = sect.Data()
+	return
+}
+
+func findPlan9Symbol(f *plan9obj.File, name string) (*plan9obj.Sym, error) {
+	syms, err := f.Symbols()
+	if err != nil {
+		return nil, err
+	}
+	for _, s := range syms {
+		if s.Name != name {
+			continue
+		}
+		return &s, nil
+	}
+	return nil, fmt.Errorf("no %s symbol found", name)
+}
+
+func loadPlan9Table(f *plan9obj.File, sname, ename string) ([]byte, error) {
+	ssym, err := findPlan9Symbol(f, sname)
+	if err != nil {
+		return nil, err
+	}
+	esym, err := findPlan9Symbol(f, ename)
+	if err != nil {
+		return nil, err
+	}
+	sect := f.Section("text")
+	if sect == nil {
+		return nil, err
+	}
+	data, err := sect.Data()
+	if err != nil {
+		return nil, err
+	}
+	textStart := f.LoadAddress + f.HdrSize
+	return data[ssym.Value-textStart : esym.Value-textStart], nil
+}
+
+func (f *plan9File) goarch() string {
+	switch f.plan9.Magic {
+	case plan9obj.Magic386:
+		return "386"
+	case plan9obj.MagicAMD64:
+		return "amd64"
+	case plan9obj.MagicARM:
+		return "arm"
+	}
+	return ""
+}
+
+func (f *plan9File) loadAddress() (uint64, error) {
+	return 0, fmt.Errorf("unknown load address")
+}
+
+func (f *plan9File) dwarf() (*dwarf.Data, error) {
+	return nil, errors.New("no DWARF data in Plan 9 file")
+}
diff --git a/src/cmd/internal/objfile/xcoff.go b/src/cmd/internal/objfile/xcoff.go
new file mode 100644
index 0000000..d6df4db
--- /dev/null
+++ b/src/cmd/internal/objfile/xcoff.go
@@ -0,0 +1,163 @@
+// Copyright 2018 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.
+
+// Parsing of XCOFF executable (AIX)
+
+package objfile
+
+import (
+	"debug/dwarf"
+	"fmt"
+	"internal/xcoff"
+	"io"
+	"unicode"
+)
+
+type xcoffFile struct {
+	xcoff *xcoff.File
+}
+
+func openXcoff(r io.ReaderAt) (rawFile, error) {
+	f, err := xcoff.NewFile(r)
+	if err != nil {
+		return nil, err
+	}
+	return &xcoffFile{f}, nil
+}
+
+func (f *xcoffFile) symbols() ([]Sym, error) {
+	var syms []Sym
+	for _, s := range f.xcoff.Symbols {
+		const (
+			N_UNDEF = 0  // An undefined (extern) symbol
+			N_ABS   = -1 // An absolute symbol (e_value is a constant, not an address)
+			N_DEBUG = -2 // A debugging symbol
+		)
+		sym := Sym{Name: s.Name, Addr: s.Value, Code: '?'}
+
+		switch s.SectionNumber {
+		case N_UNDEF:
+			sym.Code = 'U'
+		case N_ABS:
+			sym.Code = 'C'
+		case N_DEBUG:
+			sym.Code = '?'
+		default:
+			if s.SectionNumber < 0 || len(f.xcoff.Sections) < int(s.SectionNumber) {
+				return nil, fmt.Errorf("invalid section number in symbol table")
+			}
+			sect := f.xcoff.Sections[s.SectionNumber-1]
+
+			// debug/xcoff returns an offset in the section not the actual address
+			sym.Addr += sect.VirtualAddress
+
+			if s.AuxCSect.SymbolType&0x3 == xcoff.XTY_LD {
+				// The size of a function is contained in the
+				// AUX_FCN entry
+				sym.Size = s.AuxFcn.Size
+			} else {
+				sym.Size = s.AuxCSect.Length
+			}
+
+			sym.Size = s.AuxCSect.Length
+
+			switch sect.Type {
+			case xcoff.STYP_TEXT:
+				if s.AuxCSect.StorageMappingClass == xcoff.XMC_RO {
+					sym.Code = 'R'
+				} else {
+					sym.Code = 'T'
+				}
+			case xcoff.STYP_DATA:
+				sym.Code = 'D'
+			case xcoff.STYP_BSS:
+				sym.Code = 'B'
+			}
+
+			if s.StorageClass == xcoff.C_HIDEXT {
+				// Local symbol
+				sym.Code = unicode.ToLower(sym.Code)
+			}
+
+		}
+		syms = append(syms, sym)
+	}
+
+	return syms, nil
+}
+
+func (f *xcoffFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
+	if sect := f.xcoff.Section(".text"); sect != nil {
+		textStart = sect.VirtualAddress
+	}
+	if pclntab, err = loadXCOFFTable(f.xcoff, "runtime.pclntab", "runtime.epclntab"); err != nil {
+		return 0, nil, nil, err
+	}
+	symtab, _ = loadXCOFFTable(f.xcoff, "runtime.symtab", "runtime.esymtab") // ignore error, this symbol is not useful anyway
+	return textStart, symtab, pclntab, nil
+}
+
+func (f *xcoffFile) text() (textStart uint64, text []byte, err error) {
+	sect := f.xcoff.Section(".text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = sect.VirtualAddress
+	text, err = sect.Data()
+	return
+}
+
+func findXCOFFSymbol(f *xcoff.File, name string) (*xcoff.Symbol, error) {
+	for _, s := range f.Symbols {
+		if s.Name != name {
+			continue
+		}
+		if s.SectionNumber <= 0 {
+			return nil, fmt.Errorf("symbol %s: invalid section number %d", name, s.SectionNumber)
+		}
+		if len(f.Sections) < int(s.SectionNumber) {
+			return nil, fmt.Errorf("symbol %s: section number %d is larger than max %d", name, s.SectionNumber, len(f.Sections))
+		}
+		return s, nil
+	}
+	return nil, fmt.Errorf("no %s symbol found", name)
+}
+
+func loadXCOFFTable(f *xcoff.File, sname, ename string) ([]byte, error) {
+	ssym, err := findXCOFFSymbol(f, sname)
+	if err != nil {
+		return nil, err
+	}
+	esym, err := findXCOFFSymbol(f, ename)
+	if err != nil {
+		return nil, err
+	}
+	if ssym.SectionNumber != esym.SectionNumber {
+		return nil, fmt.Errorf("%s and %s symbols must be in the same section", sname, ename)
+	}
+	sect := f.Sections[ssym.SectionNumber-1]
+	data, err := sect.Data()
+	if err != nil {
+		return nil, err
+	}
+	return data[ssym.Value:esym.Value], nil
+}
+
+func (f *xcoffFile) goarch() string {
+	switch f.xcoff.TargetMachine {
+	case xcoff.U802TOCMAGIC:
+		return "ppc"
+	case xcoff.U64_TOCMAGIC:
+		return "ppc64"
+	}
+	return ""
+}
+
+func (f *xcoffFile) loadAddress() (uint64, error) {
+	return 0, fmt.Errorf("unknown load address")
+}
+
+func (f *xcoffFile) dwarf() (*dwarf.Data, error) {
+	return f.xcoff.DWARF()
+}