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https://github.com/golang/go
synced 2024-11-23 22:20:02 -07:00
cmd/internal/obj, cmd/link: put all symbol data in one contiguous section
Another object file change, gives a reasonable improvement: name old s/op new s/op delta LinkCmdGo 0.46 ± 3% 0.44 ± 9% -3.34% (p=0.000 n=98+82) LinkJuju 4.09 ± 4% 3.92 ± 5% -4.30% (p=0.000 n=98+99) I guess the data section could be mmap-ed instead of read, I haven't tried that. Change-Id: I959eee470a05526ab1579e3f5d3ede41c16c954f Reviewed-on: https://go-review.googlesource.com/20928 Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org>
This commit is contained in:
Michael Hudson-Doyle
parent
34f0c0b3de
commit
36d5650a1c
@ -241,6 +241,7 @@ type objReader struct {
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f io.ReadSeeker
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err error
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offset int64
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dataOffset int64
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limit int64
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tmp [256]byte
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pkg string
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@ -416,8 +417,8 @@ func (r *objReader) readRef() {
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// readData reads a data reference from the input file.
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func (r *objReader) readData() Data {
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n := r.readInt()
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d := Data{Offset: r.offset, Size: int64(n)}
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r.skip(int64(n))
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d := Data{Offset: r.dataOffset, Size: int64(n)}
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r.dataOffset += int64(n)
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return d
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}
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@ -610,6 +611,10 @@ func (r *objReader) parseObject(prefix []byte) error {
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r.readRef()
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}
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dataLength := r.readInt()
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r.dataOffset = r.offset
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r.skip(int64(dataLength))
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// Symbols.
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for {
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if b := r.readByte(); b != 0xfe {
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@ -19,8 +19,10 @@
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// - byte 1 - version number
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// - sequence of strings giving dependencies (imported packages)
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// - empty string (marks end of sequence)
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// - sequence of sybol references used by the defined symbols
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// - sequence of symbol references used by the defined symbols
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// - byte 0xff (marks end of sequence)
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// - integer (length of following data)
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// - data, the content of the defined symbols
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// - sequence of defined symbols
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// - byte 0xff (marks end of sequence)
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// - magic footer: "\xff\xffgo13ld"
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@ -96,9 +98,6 @@
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//
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// TODO(rsc): The file format is good for a first pass but needs work.
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// - There are SymID in the object file that should really just be strings.
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// - The actual symbol memory images are interlaced with the symbol
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// metadata. They should be separated, to reduce the I/O required to
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// load just the metadata.
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package obj
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@ -319,15 +318,42 @@ func Writeobjfile(ctxt *Link, b *Biobuf) {
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}
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wrstring(b, "")
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var dataLength int64
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// Emit symbol references.
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for _, s := range ctxt.Text {
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writerefs(ctxt, b, s)
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dataLength += int64(len(s.P))
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pc := s.Pcln
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dataLength += int64(len(pc.Pcsp.P))
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dataLength += int64(len(pc.Pcfile.P))
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dataLength += int64(len(pc.Pcline.P))
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for i := 0; i < len(pc.Pcdata); i++ {
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dataLength += int64(len(pc.Pcdata[i].P))
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}
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}
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for _, s := range ctxt.Data {
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writerefs(ctxt, b, s)
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dataLength += int64(len(s.P))
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}
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Bputc(b, 0xff)
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// Write data block
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wrint(b, dataLength)
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for _, s := range ctxt.Text {
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b.w.Write(s.P)
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pc := s.Pcln
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b.w.Write(pc.Pcsp.P)
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b.w.Write(pc.Pcfile.P)
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b.w.Write(pc.Pcline.P)
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for i := 0; i < len(pc.Pcdata); i++ {
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b.w.Write(pc.Pcdata[i].P)
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}
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}
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for _, s := range ctxt.Data {
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b.w.Write(s.P)
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}
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// Emit symbols.
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for _, s := range ctxt.Text {
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writesym(ctxt, b, s)
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@ -480,7 +506,7 @@ func writesym(ctxt *Link, b *Biobuf, s *LSym) {
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wrint(b, flags)
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wrint(b, s.Size)
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wrsym(b, s.Gotype)
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wrdata(b, s.P)
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wrint(b, int64(len(s.P)))
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wrint(b, int64(len(s.R)))
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var r *Reloc
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@ -521,12 +547,12 @@ func writesym(ctxt *Link, b *Biobuf, s *LSym) {
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}
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pc := s.Pcln
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wrdata(b, pc.Pcsp.P)
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wrdata(b, pc.Pcfile.P)
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wrdata(b, pc.Pcline.P)
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wrint(b, int64(len(pc.Pcsp.P)))
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wrint(b, int64(len(pc.Pcfile.P)))
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wrint(b, int64(len(pc.Pcline.P)))
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wrint(b, int64(len(pc.Pcdata)))
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for i := 0; i < len(pc.Pcdata); i++ {
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wrdata(b, pc.Pcdata[i].P)
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wrint(b, int64(len(pc.Pcdata[i].P)))
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}
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wrint(b, int64(len(pc.Funcdataoff)))
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for i := 0; i < len(pc.Funcdataoff); i++ {
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@ -564,11 +590,6 @@ func wrstring(b *Biobuf, s string) {
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b.w.WriteString(s)
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}
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func wrdata(b *Biobuf, v []byte) {
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wrint(b, int64(len(v)))
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b.Write(v)
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}
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func wrsym(b *Biobuf, s *LSym) {
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if s == nil {
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wrint(b, 0)
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@ -23,6 +23,8 @@ package ld
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// - empty string (marks end of sequence)
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// - sequence of sybol references used by the defined symbols
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// - byte 0xff (marks end of sequence)
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// - integer (length of following data)
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// - data, the content of the defined symbols
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// - sequence of defined symbols
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// - byte 0xff (marks end of sequence)
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// - magic footer: "\xff\xffgo13ld"
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@ -98,9 +100,6 @@ package ld
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//
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// TODO(rsc): The file format is good for a first pass but needs work.
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// - There are SymID in the object file that should really just be strings.
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// - The actual symbol memory images are interlaced with the symbol
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// metadata. They should be separated, to reduce the I/O required to
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// load just the metadata.
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import (
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"bytes"
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@ -151,6 +150,10 @@ func ldobjfile(ctxt *Link, f *obj.Biobuf, pkg string, length int64, pn string) {
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readref(ctxt, f, pkg, pn)
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}
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dataLength := rdint64(f)
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data := make([]byte, dataLength)
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obj.Bread(f, data)
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for {
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c, err := f.Peek(1)
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if err != nil {
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@ -159,7 +162,7 @@ func ldobjfile(ctxt *Link, f *obj.Biobuf, pkg string, length int64, pn string) {
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if c[0] == 0xff {
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break
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}
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readsym(ctxt, f, pkg, pn)
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readsym(ctxt, f, &data, pkg, pn)
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}
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buf = [8]uint8{}
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@ -173,7 +176,7 @@ func ldobjfile(ctxt *Link, f *obj.Biobuf, pkg string, length int64, pn string) {
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}
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}
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func readsym(ctxt *Link, f *obj.Biobuf, pkg string, pn string) {
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func readsym(ctxt *Link, f *obj.Biobuf, buf *[]byte, pkg string, pn string) {
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if obj.Bgetc(f) != 0xfe {
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log.Fatalf("readsym out of sync")
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}
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@ -184,7 +187,7 @@ func readsym(ctxt *Link, f *obj.Biobuf, pkg string, pn string) {
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local := flags&2 != 0
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size := rdint(f)
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typ := rdsym(ctxt, f, pkg)
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data := rddata(f)
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data := rddata(f, buf)
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nreloc := rdint(f)
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var dup *LSym
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@ -283,14 +286,14 @@ overwrite:
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s.Pcln = new(Pcln)
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pc := s.Pcln
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pc.Pcsp.P = rddata(f)
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pc.Pcfile.P = rddata(f)
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pc.Pcline.P = rddata(f)
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pc.Pcsp.P = rddata(f, buf)
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pc.Pcfile.P = rddata(f, buf)
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pc.Pcline.P = rddata(f, buf)
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n = rdint(f)
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pc.Pcdata = make([]Pcdata, n)
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pc.Npcdata = n
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for i := 0; i < n; i++ {
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pc.Pcdata[i].P = rddata(f)
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pc.Pcdata[i].P = rddata(f, buf)
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}
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n = rdint(f)
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pc.Funcdata = make([]*LSym, n)
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@ -482,23 +485,10 @@ func rdstring(f *obj.Biobuf) string {
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return string(rdBuf[:n])
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}
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const rddataBufMax = 1 << 14
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var rddataBuf = make([]byte, rddataBufMax)
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func rddata(f *obj.Biobuf) []byte {
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var p []byte
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func rddata(f *obj.Biobuf, buf *[]byte) []byte {
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n := rdint(f)
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if n > rddataBufMax {
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p = make([]byte, n)
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} else {
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if len(rddataBuf) < n {
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rddataBuf = make([]byte, rddataBufMax)
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}
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p = rddataBuf[:n:n]
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rddataBuf = rddataBuf[n:]
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}
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obj.Bread(f, p)
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p := (*buf)[:n:n]
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*buf = (*buf)[n:]
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return p
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}
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