[dev.link] cmd/compile, cmd/asm: delete old object file format support

There are more cleanups to do, but I want to keep this CL mostly
a pure deletion.

Change-Id: Icd2ff0a4b648eb4adf3d29386542617e49620818
Reviewed-on: https://go-review.googlesource.com/c/go/+/206398
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/asm/internal/flags/flags.go

@@ -23,7 +23,6 @@ var (
 	Dynlink    = flag.Bool("dynlink", false, "support references to Go symbols defined in other shared libraries")
 	AllErrors  = flag.Bool("e", false, "no limit on number of errors reported")
 	SymABIs    = flag.Bool("gensymabis", false, "write symbol ABI information to output file, don't assemble")
-	Newobj     = flag.Bool("newobj", true, "use new object file format")
 )
 
 var (

src/cmd/asm/main.go

@@ -40,7 +40,6 @@ func main() {
 	}
 	ctxt.Flag_dynlink = *flags.Dynlink
 	ctxt.Flag_shared = *flags.Shared || *flags.Dynlink
-	ctxt.Flag_newobj = *flags.Newobj
 	ctxt.Bso = bufio.NewWriter(os.Stdout)
 	defer ctxt.Bso.Flush()
 

src/cmd/compile/internal/gc/iexport.go

@@ -991,7 +991,6 @@ func (w *exportWriter) linkname(s *types.Sym) {
 }
 
 func (w *exportWriter) symIdx(s *types.Sym) {
-	if Ctxt.Flag_newobj {
 	lsym := s.Linksym()
 	if lsym.PkgIdx > goobj2.PkgIdxSelf || (lsym.PkgIdx == goobj2.PkgIdxInvalid && !lsym.Indexed()) || s.Linkname != "" {
 		// Don't export index for non-package symbols, linkname'd symbols,
@@ -1003,7 +1002,6 @@ func (w *exportWriter) symIdx(s *types.Sym) {
 		// For re-exporting an imported symbol, pass its index through.
 		w.int64(int64(lsym.SymIdx))
 	}
-	}
 }
 
 // Inline bodies.

src/cmd/compile/internal/gc/iimport.go

@@ -687,7 +687,6 @@ func (r *importReader) linkname(s *types.Sym) {
 }
 
 func (r *importReader) symIdx(s *types.Sym) {
-	if Ctxt.Flag_newobj {
 	lsym := s.Linksym()
 	idx := int32(r.int64())
 	if idx != -1 {
@@ -697,7 +696,6 @@ func (r *importReader) symIdx(s *types.Sym) {
 		lsym.SymIdx = idx
 		lsym.Set(obj.AttrIndexed, true)
 	}
-	}
 }
 
 func (r *importReader) doInline(n *Node) {

src/cmd/compile/internal/gc/main.go

@@ -277,7 +277,6 @@ func Main(archInit func(*Arch)) {
 	flag.StringVar(&benchfile, "bench", "", "append benchmark times to `file`")
 	flag.BoolVar(&smallFrames, "smallframes", false, "reduce the size limit for stack allocated objects")
 	flag.BoolVar(&Ctxt.UseBASEntries, "dwarfbasentries", Ctxt.UseBASEntries, "use base address selection entries in DWARF")
-	flag.BoolVar(&Ctxt.Flag_newobj, "newobj", true, "use new object file format")
 	flag.StringVar(&jsonLogOpt, "json", "", "version,destination for JSON compiler/optimizer logging")
 
 	objabi.Flagparse(usage)
@@ -285,7 +284,7 @@ func Main(archInit func(*Arch)) {
 	// Record flags that affect the build result. (And don't
 	// record flags that don't, since that would cause spurious
 	// changes in the binary.)
-	recordFlags("B", "N", "l", "msan", "race", "shared", "dynlink", "dwarflocationlists", "dwarfbasentries", "smallframes", "newobj")
+	recordFlags("B", "N", "l", "msan", "race", "shared", "dynlink", "dwarflocationlists", "dwarfbasentries", "smallframes")
 
 	if smallFrames {
 		maxStackVarSize = 128 * 1024

src/cmd/internal/obj/link.go

@@ -652,7 +652,6 @@ type Link struct {
 	Flag_linkshared    bool
 	Flag_optimize      bool
 	Flag_locationlists bool
-	Flag_newobj        bool // use new object file format
 	Bso                *bufio.Writer
 	Pathname           string
 	hashmu             sync.Mutex       // protects hash, funchash

src/cmd/internal/obj/objfile.go

@@ -7,225 +7,17 @@
 package obj
 
 import (
-	"bufio"
 	"cmd/internal/bio"
 	"cmd/internal/dwarf"
 	"cmd/internal/objabi"
 	"cmd/internal/sys"
 	"fmt"
-	"log"
-	"path/filepath"
 	"sort"
-	"strings"
 	"sync"
 )
 
-// objWriter writes Go object files.
-type objWriter struct {
-	wr   *bufio.Writer
-	ctxt *Link
-	// Temporary buffer for zigzag int writing.
-	varintbuf [10]uint8
-
-	// Number of objects written of each type.
-	nRefs     int
-	nData     int
-	nReloc    int
-	nPcdata   int
-	nFuncdata int
-	nFile     int
-
-	pkgpath string // the package import path (escaped), "" if unknown
-}
-
-func (w *objWriter) addLengths(s *LSym) {
-	w.nData += len(s.P)
-	w.nReloc += len(s.R)
-
-	if s.Type != objabi.STEXT {
-		return
-	}
-
-	pc := &s.Func.Pcln
-
-	data := 0
-	data += len(pc.Pcsp.P)
-	data += len(pc.Pcfile.P)
-	data += len(pc.Pcline.P)
-	data += len(pc.Pcinline.P)
-	for _, pcd := range pc.Pcdata {
-		data += len(pcd.P)
-	}
-
-	w.nData += data
-	w.nPcdata += len(pc.Pcdata)
-
-	w.nFuncdata += len(pc.Funcdataoff)
-	w.nFile += len(pc.File)
-}
-
-func (w *objWriter) writeLengths() {
-	w.writeInt(int64(w.nData))
-	w.writeInt(int64(w.nReloc))
-	w.writeInt(int64(w.nPcdata))
-	w.writeInt(int64(0)) // TODO: remove at next object file rev
-	w.writeInt(int64(w.nFuncdata))
-	w.writeInt(int64(w.nFile))
-}
-
-func newObjWriter(ctxt *Link, b *bufio.Writer, pkgpath string) *objWriter {
-	return &objWriter{
-		ctxt:    ctxt,
-		wr:      b,
-		pkgpath: objabi.PathToPrefix(pkgpath),
-	}
-}
-
 func WriteObjFile(ctxt *Link, bout *bio.Writer, pkgpath string) {
-	if ctxt.Flag_newobj {
 	WriteObjFile2(ctxt, bout, pkgpath)
-		return
-	}
-
-	b := bout.Writer
-	w := newObjWriter(ctxt, b, pkgpath)
-
-	// Magic header
-	w.wr.WriteString("\x00go114ld")
-
-	// Version
-	w.wr.WriteByte(1)
-
-	// Autolib
-	for _, pkg := range ctxt.Imports {
-		w.writeString(pkg)
-	}
-	w.writeString("")
-
-	// DWARF File Table
-	fileTable := ctxt.PosTable.DebugLinesFileTable()
-	w.writeInt(int64(len(fileTable)))
-	for _, str := range fileTable {
-		w.writeString(str)
-	}
-
-	// Symbol references
-	for _, s := range ctxt.Text {
-		w.writeRefs(s)
-		w.addLengths(s)
-	}
-
-	if ctxt.Headtype == objabi.Haix {
-		// Data must be sorted to keep a constant order in TOC symbols.
-		// As they are created during Progedit, two symbols can be switched between
-		// two different compilations. Therefore, BuildID will be different.
-		// TODO: find a better place and optimize to only sort TOC symbols
-		sort.Slice(ctxt.Data, func(i, j int) bool {
-			return ctxt.Data[i].Name < ctxt.Data[j].Name
-		})
-	}
-
-	for _, s := range ctxt.Data {
-		w.writeRefs(s)
-		w.addLengths(s)
-	}
-	for _, s := range ctxt.ABIAliases {
-		w.writeRefs(s)
-		w.addLengths(s)
-	}
-	// End symbol references
-	w.wr.WriteByte(0xff)
-
-	// Lengths
-	w.writeLengths()
-
-	// Data block
-	for _, s := range ctxt.Text {
-		w.wr.Write(s.P)
-		pc := &s.Func.Pcln
-		w.wr.Write(pc.Pcsp.P)
-		w.wr.Write(pc.Pcfile.P)
-		w.wr.Write(pc.Pcline.P)
-		w.wr.Write(pc.Pcinline.P)
-		for _, pcd := range pc.Pcdata {
-			w.wr.Write(pcd.P)
-		}
-	}
-	for _, s := range ctxt.Data {
-		if len(s.P) > 0 {
-			switch s.Type {
-			case objabi.SBSS, objabi.SNOPTRBSS, objabi.STLSBSS:
-				ctxt.Diag("cannot provide data for %v sym %v", s.Type, s.Name)
-			}
-		}
-		w.wr.Write(s.P)
-	}
-
-	// Symbols
-	for _, s := range ctxt.Text {
-		w.writeSym(s)
-	}
-	for _, s := range ctxt.Data {
-		w.writeSym(s)
-	}
-	for _, s := range ctxt.ABIAliases {
-		w.writeSym(s)
-	}
-
-	// Magic footer
-	w.wr.WriteString("\xffgo114ld")
-}
-
-// Symbols are prefixed so their content doesn't get confused with the magic footer.
-const symPrefix = 0xfe
-
-func (w *objWriter) writeRef(s *LSym, isPath bool) {
-	if s == nil || s.RefIdx != 0 {
-		return
-	}
-	w.wr.WriteByte(symPrefix)
-	if isPath {
-		w.writeString(filepath.ToSlash(s.Name))
-	} else if w.pkgpath != "" {
-		// w.pkgpath is already escaped.
-		n := strings.Replace(s.Name, "\"\".", w.pkgpath+".", -1)
-		w.writeString(n)
-	} else {
-		w.writeString(s.Name)
-	}
-	// Write ABI/static information.
-	abi := int64(s.ABI())
-	if s.Static() {
-		abi = -1
-	}
-	w.writeInt(abi)
-	w.nRefs++
-	s.RefIdx = w.nRefs
-}
-
-func (w *objWriter) writeRefs(s *LSym) {
-	w.writeRef(s, false)
-	w.writeRef(s.Gotype, false)
-	for _, r := range s.R {
-		w.writeRef(r.Sym, false)
-	}
-
-	if s.Type == objabi.STEXT {
-		pc := &s.Func.Pcln
-		for _, d := range pc.Funcdata {
-			w.writeRef(d, false)
-		}
-		for _, f := range pc.File {
-			fsym := w.ctxt.Lookup(f)
-			w.writeRef(fsym, true)
-		}
-		for _, call := range pc.InlTree.nodes {
-			w.writeRef(call.Func, false)
-			f, _ := linkgetlineFromPos(w.ctxt, call.Pos)
-			fsym := w.ctxt.Lookup(f)
-			w.writeRef(fsym, true)
-		}
-	}
 }
 
 func (ctxt *Link) writeSymDebug(s *LSym) {
@@ -305,137 +97,6 @@ func (ctxt *Link) writeSymDebug(s *LSym) {
 	}
 }
 
-func (w *objWriter) writeSym(s *LSym) {
-	ctxt := w.ctxt
-	if ctxt.Debugasm > 0 {
-		w.ctxt.writeSymDebug(s)
-	}
-
-	w.wr.WriteByte(symPrefix)
-	w.wr.WriteByte(byte(s.Type))
-	w.writeRefIndex(s)
-	flags := int64(0)
-	if s.DuplicateOK() {
-		flags |= 1
-	}
-	if s.Local() {
-		flags |= 1 << 1
-	}
-	if s.MakeTypelink() {
-		flags |= 1 << 2
-	}
-	w.writeInt(flags)
-	w.writeInt(s.Size)
-	w.writeRefIndex(s.Gotype)
-	w.writeInt(int64(len(s.P)))
-
-	w.writeInt(int64(len(s.R)))
-	var r *Reloc
-	for i := range s.R {
-		r = &s.R[i]
-		w.writeInt(int64(r.Off))
-		w.writeInt(int64(r.Siz))
-		w.writeInt(int64(r.Type))
-		w.writeInt(r.Add)
-		w.writeRefIndex(r.Sym)
-	}
-
-	if s.Type != objabi.STEXT {
-		return
-	}
-
-	w.writeInt(int64(s.Func.Args))
-	w.writeInt(int64(s.Func.Locals))
-	w.writeBool(s.NoSplit())
-	flags = int64(0)
-	if s.Leaf() {
-		flags |= 1
-	}
-	if s.CFunc() {
-		flags |= 1 << 1
-	}
-	if s.ReflectMethod() {
-		flags |= 1 << 2
-	}
-	if ctxt.Flag_shared {
-		flags |= 1 << 3
-	}
-	if s.TopFrame() {
-		flags |= 1 << 4
-	}
-	w.writeInt(flags)
-	w.writeInt(int64(0)) // TODO: remove at next object file rev
-
-	pc := &s.Func.Pcln
-	w.writeInt(int64(len(pc.Pcsp.P)))
-	w.writeInt(int64(len(pc.Pcfile.P)))
-	w.writeInt(int64(len(pc.Pcline.P)))
-	w.writeInt(int64(len(pc.Pcinline.P)))
-	w.writeInt(int64(len(pc.Pcdata)))
-	for _, pcd := range pc.Pcdata {
-		w.writeInt(int64(len(pcd.P)))
-	}
-	w.writeInt(int64(len(pc.Funcdataoff)))
-	for i := range pc.Funcdataoff {
-		w.writeRefIndex(pc.Funcdata[i])
-	}
-	for i := range pc.Funcdataoff {
-		w.writeInt(pc.Funcdataoff[i])
-	}
-	w.writeInt(int64(len(pc.File)))
-	for _, f := range pc.File {
-		fsym := ctxt.Lookup(f)
-		w.writeRefIndex(fsym)
-	}
-	w.writeInt(int64(len(pc.InlTree.nodes)))
-	for _, call := range pc.InlTree.nodes {
-		w.writeInt(int64(call.Parent))
-		f, l := linkgetlineFromPos(w.ctxt, call.Pos)
-		fsym := ctxt.Lookup(f)
-		w.writeRefIndex(fsym)
-		w.writeInt(int64(l))
-		w.writeRefIndex(call.Func)
-		w.writeInt(int64(call.ParentPC))
-	}
-}
-
-func (w *objWriter) writeBool(b bool) {
-	if b {
-		w.writeInt(1)
-	} else {
-		w.writeInt(0)
-	}
-}
-
-func (w *objWriter) writeInt(sval int64) {
-	var v uint64
-	uv := (uint64(sval) << 1) ^ uint64(sval>>63)
-	p := w.varintbuf[:]
-	for v = uv; v >= 0x80; v >>= 7 {
-		p[0] = uint8(v | 0x80)
-		p = p[1:]
-	}
-	p[0] = uint8(v)
-	p = p[1:]
-	w.wr.Write(w.varintbuf[:len(w.varintbuf)-len(p)])
-}
-
-func (w *objWriter) writeString(s string) {
-	w.writeInt(int64(len(s)))
-	w.wr.WriteString(s)
-}
-
-func (w *objWriter) writeRefIndex(s *LSym) {
-	if s == nil {
-		w.writeInt(0)
-		return
-	}
-	if s.RefIdx == 0 {
-		log.Fatalln("writing an unreferenced symbol", s.Name)
-	}
-	w.writeInt(int64(s.RefIdx))
-}
-
 // relocByOff sorts relocations by their offsets.
 type relocByOff []Reloc
 

src/cmd/internal/obj/sym.go

@@ -164,10 +164,6 @@ func (ctxt *Link) Int64Sym(i int64) *LSym {
 // asm is set to true if this is called by the assembler (i.e. not the compiler),
 // in which case all the symbols are non-package (for now).
 func (ctxt *Link) NumberSyms(asm bool) {
-	if !ctxt.Flag_newobj {
-		return
-	}
-
 	if ctxt.Headtype == objabi.Haix {
 		// Data must be sorted to keep a constant order in TOC symbols.
 		// As they are created during Progedit, two symbols can be switched between