From: Shahar Kohanim Date: Tue, 22 Mar 2016 22:44:07 +0000 (+0200) Subject: cmd/compile, cmd/link: record lengths in object file X-Git-Tag: go1.7beta1~1025 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=7f067c87d831f329d068fced1b136cd06039303c;p=gostls13.git cmd/compile, cmd/link: record lengths in object file Record total number of relocations, pcdata, automatics, funcdata and files in object file and use these numbers in the linker to allocate contiguous slices to later be filled by the defined symbols. name old secs new secs delta LinkCmdGo 0.52 ± 3% 0.49 ± 3% -4.21% (p=0.000 n=91+92) LinkJuju 4.48 ± 4% 4.21 ± 7% -6.08% (p=0.000 n=96+100) name old MaxRSS new MaxRSS delta LinkCmdGo 122k ± 2% 120k ± 4% -1.66% (p=0.000 n=98+93) LinkJuju 799k ± 5% 865k ± 8% +8.29% (p=0.000 n=89+99) GOGC=off name old secs new secs delta LinkCmdGo 0.42 ± 2% 0.41 ± 0% -2.98% (p=0.000 n=89+70) LinkJuju 3.61 ± 0% 3.52 ± 1% -2.46% (p=0.000 n=80+89) name old MaxRSS new MaxRSS delta LinkCmdGo 130k ± 1% 128k ± 1% -1.33% (p=0.000 n=100+100) LinkJuju 1.00M ± 0% 0.99M ± 0% -1.70% (p=0.000 n=100+100) Change-Id: Ie08f6ccd4311bb78d8950548c678230a58635c73 Reviewed-on: https://go-review.googlesource.com/21026 Reviewed-by: David Crawshaw Run-TryBot: David Crawshaw TryBot-Result: Gobot Gobot --- diff --git a/src/cmd/internal/goobj/read.go b/src/cmd/internal/goobj/read.go index 2506f07de2..d64f4cbce1 100644 --- a/src/cmd/internal/goobj/read.go +++ b/src/cmd/internal/goobj/read.go @@ -614,6 +614,12 @@ func (r *objReader) parseObject(prefix []byte) error { } dataLength := r.readInt() + r.readInt() // n relocations - ignore + r.readInt() // n pcdata - ignore + r.readInt() // n autom - ignore + r.readInt() // n funcdata - ignore + r.readInt() // n files - ignore + r.dataOffset = r.offset r.skip(int64(dataLength)) diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go index b9eb8014ec..aba832f27b 100644 --- a/src/cmd/internal/obj/objfile.go +++ b/src/cmd/internal/obj/objfile.go @@ -21,7 +21,13 @@ // - empty string (marks end of sequence) // - sequence of symbol references used by the defined symbols // - byte 0xff (marks end of sequence) -// - integer (length of following data) +// - sequence of integer lengths: +// - total data length +// - total number of relocations +// - total number of pcdata +// - total number of automatics +// - total number of funcdata +// - total number of files // - data, the content of the defined symbols // - sequence of defined symbols // - byte 0xff (marks end of sequence) @@ -303,6 +309,54 @@ func flushplist(ctxt *Link, freeProgs bool) { } } +type sectionLengths struct { + data int + reloc int + pcdata int + autom int + funcdata int + file int +} + +func (l *sectionLengths) add(s *LSym) { + l.data += len(s.P) + l.reloc += len(s.R) + + if s.Type != STEXT { + return + } + + pc := s.Pcln + + data := 0 + data += len(pc.Pcsp.P) + data += len(pc.Pcfile.P) + data += len(pc.Pcline.P) + for i := 0; i < len(pc.Pcdata); i++ { + data += len(pc.Pcdata[i].P) + } + + l.data += data + l.pcdata += len(pc.Pcdata) + + autom := 0 + for a := s.Autom; a != nil; a = a.Link { + autom++ + } + l.autom += autom + l.funcdata += len(pc.Funcdataoff) + l.file += len(pc.File) +} + +func wrlengths(b *Biobuf, sl sectionLengths) { + wrint(b, int64(sl.data)) + wrint(b, int64(sl.reloc)) + wrint(b, int64(sl.pcdata)) + wrint(b, int64(sl.autom)) + wrint(b, int64(sl.funcdata)) + wrint(b, int64(sl.file)) +} + func Writeobjfile(ctxt *Link, b *Biobuf) { // Emit header. Bputc(b, 0) @@ -317,28 +371,22 @@ func Writeobjfile(ctxt *Link, b *Biobuf) { } wrstring(b, "") - var dataLength int64 + var lengths sectionLengths + // Emit symbol references. for _, s := range ctxt.Text { writerefs(ctxt, b, s) - dataLength += int64(len(s.P)) - - pc := s.Pcln - dataLength += int64(len(pc.Pcsp.P)) - dataLength += int64(len(pc.Pcfile.P)) - dataLength += int64(len(pc.Pcline.P)) - for i := 0; i < len(pc.Pcdata); i++ { - dataLength += int64(len(pc.Pcdata[i].P)) - } + lengths.add(s) } for _, s := range ctxt.Data { writerefs(ctxt, b, s) - dataLength += int64(len(s.P)) + lengths.add(s) } Bputc(b, 0xff) + wrlengths(b, lengths) + // Write data block - wrint(b, dataLength) for _, s := range ctxt.Text { b.w.Write(s.P) pc := s.Pcln diff --git a/src/cmd/link/internal/ld/objfile.go b/src/cmd/link/internal/ld/objfile.go index 2e8f01099c..b9121c6f81 100644 --- a/src/cmd/link/internal/ld/objfile.go +++ b/src/cmd/link/internal/ld/objfile.go @@ -21,9 +21,15 @@ package ld // - byte 1 - version number // - sequence of strings giving dependencies (imported packages) // - empty string (marks end of sequence) -// - sequence of sybol references used by the defined symbols +// - sequence of symbol references used by the defined symbols // - byte 0xff (marks end of sequence) -// - integer (length of following data) +// - sequence of integer lengths: +// - total data length +// - total number of relocations +// - total number of pcdata +// - total number of automatics +// - total number of funcdata +// - total number of files // - data, the content of the defined symbols // - sequence of defined symbols // - byte 0xff (marks end of sequence) @@ -149,9 +155,9 @@ func ldobjfile(ctxt *Link, f *obj.Biobuf, pkg string, length int64, pn string) { readref(ctxt, f, pkg, pn) } - dataLength := rdint64(f) - data := make([]byte, dataLength) - obj.Bread(f, data) + sl := rdslices(f) + + obj.Bread(f, sl.data) for { c, err := f.Peek(1) @@ -161,7 +167,7 @@ func ldobjfile(ctxt *Link, f *obj.Biobuf, pkg string, length int64, pn string) { if c[0] == 0xff { break } - readsym(ctxt, f, &data, pkg, pn) + readsym(ctxt, f, sl, pkg, pn) } buf = [8]uint8{} @@ -177,9 +183,38 @@ func ldobjfile(ctxt *Link, f *obj.Biobuf, pkg string, length int64, pn string) { var dupSym = &LSym{Name: ".dup"} -func readsym(ctxt *Link, f *obj.Biobuf, buf *[]byte, pkg string, pn string) { +type slices struct { + data []byte + reloc []Reloc + pcdata []Pcdata + autom []Auto + funcdata []*LSym + funcdataoff []int64 + file []*LSym +} + +func rdslices(f *obj.Biobuf) *slices { + sl := &slices{} + + n := rdint(f) + sl.data = make([]byte, n) + n = rdint(f) + sl.reloc = make([]Reloc, n) + n = rdint(f) + sl.pcdata = make([]Pcdata, n) + n = rdint(f) + sl.autom = make([]Auto, n) + n = rdint(f) + sl.funcdata = make([]*LSym, n) + sl.funcdataoff = make([]int64, n) + n = rdint(f) + sl.file = make([]*LSym, n) + return sl +} + +func readsym(ctxt *Link, f *obj.Biobuf, sl *slices, pkg string, pn string) { if obj.Bgetc(f) != 0xfe { - log.Fatalf("readsym out of sync") + log.Fatalln("readsym out of sync") } t := rdint(f) s := rdsym(ctxt, f, pkg) @@ -188,8 +223,9 @@ func readsym(ctxt *Link, f *obj.Biobuf, buf *[]byte, pkg string, pn string) { local := flags&2 != 0 size := rdint(f) typ := rdsym(ctxt, f, pkg) - data := rddata(f, buf) + data := rddata(f, &sl.data) nreloc := rdint(f) + isdup := false var dup *LSym if s.Type != 0 && s.Type != obj.SXREF { @@ -212,6 +248,7 @@ func readsym(ctxt *Link, f *obj.Biobuf, buf *[]byte, pkg string, pn string) { if len(s.P) > 0 { dup = s s = dupSym + isdup = true } } @@ -237,12 +274,16 @@ overwrite: if typ != nil { s.Gotype = typ } - if dup != nil && typ != nil { // if bss sym defined multiple times, take type from any one def + if isdup && typ != nil { // if bss sym defined multiple times, take type from any one def dup.Gotype = typ } s.P = data if nreloc > 0 { - s.R = make([]Reloc, nreloc) + s.R = sl.reloc[:nreloc:nreloc] + if !isdup { + sl.reloc = sl.reloc[nreloc:] + } + var r *Reloc for i := 0; i < nreloc; i++ { r = &s.R[i] @@ -265,7 +306,11 @@ overwrite: s.Attr |= AttrReflectMethod } n := rdint(f) - s.Autom = make([]Auto, n) + s.Autom = sl.autom[:n:n] + if !isdup { + sl.autom = sl.autom[n:] + } + for i := 0; i < n; i++ { s.Autom[i] = Auto{ Asym: rdsym(ctxt, f, pkg), @@ -277,17 +322,24 @@ overwrite: s.Pcln = new(Pcln) pc := s.Pcln - pc.Pcsp.P = rddata(f, buf) - pc.Pcfile.P = rddata(f, buf) - pc.Pcline.P = rddata(f, buf) + pc.Pcsp.P = rddata(f, &sl.data) + pc.Pcfile.P = rddata(f, &sl.data) + pc.Pcline.P = rddata(f, &sl.data) n = rdint(f) - pc.Pcdata = make([]Pcdata, n) + pc.Pcdata = sl.pcdata[:n:n] + if !isdup { + sl.pcdata = sl.pcdata[n:] + } for i := 0; i < n; i++ { - pc.Pcdata[i].P = rddata(f, buf) + pc.Pcdata[i].P = rddata(f, &sl.data) } n = rdint(f) - pc.Funcdata = make([]*LSym, n) - pc.Funcdataoff = make([]int64, n) + pc.Funcdata = sl.funcdata[:n:n] + pc.Funcdataoff = sl.funcdataoff[:n:n] + if !isdup { + sl.funcdata = sl.funcdata[n:] + sl.funcdataoff = sl.funcdataoff[n:] + } for i := 0; i < n; i++ { pc.Funcdata[i] = rdsym(ctxt, f, pkg) } @@ -295,12 +347,15 @@ overwrite: pc.Funcdataoff[i] = rdint64(f) } n = rdint(f) - pc.File = make([]*LSym, n) + pc.File = sl.file[:n:n] + if !isdup { + sl.file = sl.file[n:] + } for i := 0; i < n; i++ { pc.File[i] = rdsym(ctxt, f, pkg) } - if dup == nil { + if !isdup { if s.Attr.OnList() { log.Fatalf("symbol %s listed multiple times", s.Name) }