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cmd/link: split out Extname into cold portion of sym.Symbol
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Create a new "AuxSymbol" struct into which 'cold' or 'infrequently
set' symbol fields are located. Move the Extname field from the
main Symbol struct to AuxSymbol.

Updates #26186

Change-Id: I9e795fb0cc48f978e2818475fa073ed9f2db202d
Reviewed-on: https://go-review.googlesource.com/125476
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
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@thanm
thanm committed Aug 30, 2018
1 parent 289dce2 commit 09df9b0
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Showing 8 changed files with 70 additions and 44 deletions.
6 changes: 3 additions & 3 deletions src/cmd/link/internal/ld/elf.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1034,7 +1034,7 @@ func elfdynhash(ctxt *Link) {
need[sy.Dynid] = addelflib(&needlib, sy.Dynimplib(), sy.Dynimpvers())
}

name := sy.Extname
name := sy.Extname()
hc := elfhash(name)

b := hc % uint32(nbucket)
Expand Down Expand Up @@ -2254,7 +2254,7 @@ func elfadddynsym(ctxt *Link, s *sym.Symbol) {

d := ctxt.Syms.Lookup(".dynsym", 0)

name := s.Extname
name := s.Extname()
d.AddUint32(ctxt.Arch, uint32(Addstring(ctxt.Syms.Lookup(".dynstr", 0), name)))

/* type */
Expand Down Expand Up @@ -2297,7 +2297,7 @@ func elfadddynsym(ctxt *Link, s *sym.Symbol) {
d := ctxt.Syms.Lookup(".dynsym", 0)

/* name */
name := s.Extname
name := s.Extname()

d.AddUint32(ctxt.Arch, uint32(Addstring(ctxt.Syms.Lookup(".dynstr", 0), name)))

Expand Down
12 changes: 6 additions & 6 deletions src/cmd/link/internal/ld/go.go
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Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,7 @@ func loadcgo(ctxt *Link, file string, pkg string, p string) {
s := ctxt.Syms.Lookup(local, 0)
if s.Type == 0 || s.Type == sym.SXREF || s.Type == sym.SHOSTOBJ {
s.SetDynimplib(lib)
s.Extname = remote
s.SetExtname(remote)
s.SetDynimpvers(q)
if s.Type != sym.SHOSTOBJ {
s.Type = sym.SDYNIMPORT
Expand Down Expand Up @@ -200,15 +200,15 @@ func loadcgo(ctxt *Link, file string, pkg string, p string) {
// see issue 4878.
if s.Dynimplib() != "" {
s.ResetDyninfo()
s.Extname = ""
s.SetExtname("")
s.Type = 0
}

if !s.Attr.CgoExport() {
s.Extname = remote
s.SetExtname(remote)
dynexp = append(dynexp, s)
} else if s.Extname != remote {
fmt.Fprintf(os.Stderr, "%s: conflicting cgo_export directives: %s as %s and %s\n", os.Args[0], s.Name, s.Extname, remote)
} else if s.Extname() != remote {
fmt.Fprintf(os.Stderr, "%s: conflicting cgo_export directives: %s as %s and %s\n", os.Args[0], s.Name, s.Extname(), remote)
nerrors++
return
}
Expand Down Expand Up @@ -276,7 +276,7 @@ func Adddynsym(ctxt *Link, s *sym.Symbol) {
if ctxt.IsELF {
elfadddynsym(ctxt, s)
} else if ctxt.HeadType == objabi.Hdarwin {
Errorf(s, "adddynsym: missed symbol (Extname=%s)", s.Extname)
Errorf(s, "adddynsym: missed symbol (Extname=%s)", s.Extname())
} else if ctxt.HeadType == objabi.Hwindows {
// already taken care of
} else {
Expand Down
4 changes: 2 additions & 2 deletions src/cmd/link/internal/ld/lib.go
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Original file line number Diff line number Diff line change
Expand Up @@ -435,7 +435,7 @@ func (ctxt *Link) loadlib() {
// cgo_import_static and cgo_import_dynamic,
// then we want to make it cgo_import_dynamic
// now.
if s.Extname != "" && s.Dynimplib() != "" && !s.Attr.CgoExport() {
if s.Extname() != "" && s.Dynimplib() != "" && !s.Attr.CgoExport() {
s.Type = sym.SDYNIMPORT
} else {
s.Type = 0
Expand Down Expand Up @@ -2116,7 +2116,7 @@ func genasmsym(ctxt *Link, put func(*Link, *sym.Symbol, string, SymbolType, int6
if !s.Attr.Reachable() {
continue
}
put(ctxt, s, s.Extname, UndefinedSym, 0, nil)
put(ctxt, s, s.Extname(), UndefinedSym, 0, nil)

case sym.STLSBSS:
if ctxt.LinkMode == LinkExternal {
Expand Down
8 changes: 4 additions & 4 deletions src/cmd/link/internal/ld/macho.go
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Original file line number Diff line number Diff line change
Expand Up @@ -724,7 +724,7 @@ func (x machoscmp) Less(i, j int) bool {
return k1 < k2
}

return s1.Extname < s2.Extname
return s1.Extname() < s2.Extname()
}

func machogenasmsym(ctxt *Link) {
Expand Down Expand Up @@ -763,7 +763,7 @@ func machoShouldExport(ctxt *Link, s *sym.Symbol) bool {
if !ctxt.DynlinkingGo() || s.Attr.Local() {
return false
}
if ctxt.BuildMode == BuildModePlugin && strings.HasPrefix(s.Extname, objabi.PathToPrefix(*flagPluginPath)) {
if ctxt.BuildMode == BuildModePlugin && strings.HasPrefix(s.Extname(), objabi.PathToPrefix(*flagPluginPath)) {
return true
}
if strings.HasPrefix(s.Name, "go.itab.") {
Expand Down Expand Up @@ -798,13 +798,13 @@ func machosymtab(ctxt *Link) {
// symbols like crosscall2 are in pclntab and end up
// pointing at the host binary, breaking unwinding.
// See Issue #18190.
cexport := !strings.Contains(s.Extname, ".") && (ctxt.BuildMode != BuildModePlugin || onlycsymbol(s))
cexport := !strings.Contains(s.Extname(), ".") && (ctxt.BuildMode != BuildModePlugin || onlycsymbol(s))
if cexport || export {
symstr.AddUint8('_')
}

// replace "·" as ".", because DTrace cannot handle it.
Addstring(symstr, strings.Replace(s.Extname, "·", ".", -1))
Addstring(symstr, strings.Replace(s.Extname(), "·", ".", -1))

if s.Type == sym.SDYNIMPORT || s.Type == sym.SHOSTOBJ {
symtab.AddUint8(0x01) // type N_EXT, external symbol
Expand Down
19 changes: 10 additions & 9 deletions src/cmd/link/internal/ld/pe.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1040,14 +1040,15 @@ func initdynimport(ctxt *Link) *Dll {
// of uinptrs this function consumes. Store the argsize and discard
// the %n suffix if any.
m.argsize = -1
if i := strings.IndexByte(s.Extname, '%'); i >= 0 {
extName := s.Extname()
if i := strings.IndexByte(extName, '%'); i >= 0 {
var err error
m.argsize, err = strconv.Atoi(s.Extname[i+1:])
m.argsize, err = strconv.Atoi(extName[i+1:])
if err != nil {
Errorf(s, "failed to parse stdcall decoration: %v", err)
}
m.argsize *= ctxt.Arch.PtrSize
s.Extname = s.Extname[:i]
s.SetExtname(extName[:i])
}

m.s = s
Expand All @@ -1061,7 +1062,7 @@ func initdynimport(ctxt *Link) *Dll {
for m = d.ms; m != nil; m = m.next {
m.s.Type = sym.SDATA
m.s.Grow(int64(ctxt.Arch.PtrSize))
dynName := m.s.Extname
dynName := m.s.Extname()
// only windows/386 requires stdcall decoration
if ctxt.Arch.Family == sys.I386 && m.argsize >= 0 {
dynName += fmt.Sprintf("@%d", m.argsize)
Expand Down Expand Up @@ -1132,7 +1133,7 @@ func addimports(ctxt *Link, datsect *peSection) {
for m := d.ms; m != nil; m = m.next {
m.off = uint64(pefile.nextSectOffset) + uint64(ctxt.Out.Offset()) - uint64(startoff)
ctxt.Out.Write16(0) // hint
strput(ctxt.Out, m.s.Extname)
strput(ctxt.Out, m.s.Extname())
}
}

Expand Down Expand Up @@ -1217,7 +1218,7 @@ type byExtname []*sym.Symbol

func (s byExtname) Len() int { return len(s) }
func (s byExtname) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s byExtname) Less(i, j int) bool { return s[i].Extname < s[j].Extname }
func (s byExtname) Less(i, j int) bool { return s[i].Extname() < s[j].Extname() }

func initdynexport(ctxt *Link) {
nexport = 0
Expand All @@ -1242,7 +1243,7 @@ func addexports(ctxt *Link) {

size := binary.Size(&e) + 10*nexport + len(*flagOutfile) + 1
for i := 0; i < nexport; i++ {
size += len(dexport[i].Extname) + 1
size += len(dexport[i].Extname()) + 1
}

if nexport == 0 {
Expand Down Expand Up @@ -1286,7 +1287,7 @@ func addexports(ctxt *Link) {

for i := 0; i < nexport; i++ {
out.Write32(uint32(v))
v += len(dexport[i].Extname) + 1
v += len(dexport[i].Extname()) + 1
}

// put EXPORT Ordinal Table
Expand All @@ -1298,7 +1299,7 @@ func addexports(ctxt *Link) {
out.WriteStringN(*flagOutfile, len(*flagOutfile)+1)

for i := 0; i < nexport; i++ {
out.WriteStringN(dexport[i].Extname, len(dexport[i].Extname)+1)
out.WriteStringN(dexport[i].Extname(), len(dexport[i].Extname())+1)
}
sect.pad(out, uint32(size))
}
Expand Down
2 changes: 1 addition & 1 deletion src/cmd/link/internal/sym/sizeof_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ func TestSizeof(t *testing.T) {
_32bit uintptr // size on 32bit platforms
_64bit uintptr // size on 64bit platforms
}{
{Symbol{}, 132, 216},
{Symbol{}, 124, 200},
}

for _, tt := range tests {
Expand Down
57 changes: 41 additions & 16 deletions src/cmd/link/internal/sym/symbol.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,6 @@ import (
// Symbol is an entry in the symbol table.
type Symbol struct {
Name string
Extname string
Type SymKind
Version int16
Attr Attribute
Expand All @@ -36,7 +35,7 @@ type Symbol struct {
Outer *Symbol
Gotype *Symbol
File string
dyninfo *dynimp
auxinfo *AuxSymbol
Sect *Section
FuncInfo *FuncInfo
Lib *Library // Package defining this symbol
Expand All @@ -45,7 +44,9 @@ type Symbol struct {
R []Reloc
}

type dynimp struct {
// AuxSymbol contains less-frequently used sym.Symbol fields.
type AuxSymbol struct {
extname string
dynimplib string
dynimpvers string
}
Expand Down Expand Up @@ -268,38 +269,62 @@ func (s *Symbol) setUintXX(arch *sys.Arch, off int64, v uint64, wid int64) int64
return off + wid
}

func (s *Symbol) makeAuxInfo() {
if s.auxinfo == nil {
s.auxinfo = &AuxSymbol{extname: s.Name}
}
}

func (s *Symbol) Extname() string {
if s.auxinfo == nil {
return s.Name
}
return s.auxinfo.extname
}

func (s *Symbol) SetExtname(n string) {
if s.auxinfo == nil {
if s.Name == n {
return
}
s.makeAuxInfo()
}
s.auxinfo.extname = n
}

func (s *Symbol) Dynimplib() string {
if s.dyninfo == nil {
if s.auxinfo == nil {
return ""
}
return s.dyninfo.dynimplib
return s.auxinfo.dynimplib
}

func (s *Symbol) Dynimpvers() string {
if s.dyninfo == nil {
if s.auxinfo == nil {
return ""
}
return s.dyninfo.dynimpvers
return s.auxinfo.dynimpvers
}

func (s *Symbol) SetDynimplib(lib string) {
if s.dyninfo == nil {
s.dyninfo = &dynimp{dynimplib: lib}
} else {
s.dyninfo.dynimplib = lib
if s.auxinfo == nil {
s.makeAuxInfo()
}
s.auxinfo.dynimplib = lib
}

func (s *Symbol) SetDynimpvers(vers string) {
if s.dyninfo == nil {
s.dyninfo = &dynimp{dynimpvers: vers}
} else {
s.dyninfo.dynimpvers = vers
if s.auxinfo == nil {
s.makeAuxInfo()
}
s.auxinfo.dynimpvers = vers
}

func (s *Symbol) ResetDyninfo() {
s.dyninfo = nil
if s.auxinfo != nil {
s.auxinfo.dynimplib = ""
s.auxinfo.dynimpvers = ""
}
}

// SortSub sorts a linked-list (by Sub) of *Symbol by Value.
Expand Down
6 changes: 3 additions & 3 deletions src/cmd/link/internal/sym/symbols.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,6 @@ func (syms *Symbols) Lookup(name string, v int) *Symbol {
return s
}
s = syms.Newsym(name, v)
s.Extname = s.Name
m[name] = s
return s
}
Expand All @@ -97,9 +96,10 @@ func (syms *Symbols) IncVersion() int {
// Rename renames a symbol.
func (syms *Symbols) Rename(old, new string, v int, reachparent map[*Symbol]*Symbol) {
s := syms.hash[v][old]
oldExtName := s.Extname()
s.Name = new
if s.Extname == old {
s.Extname = new
if oldExtName == old {
s.SetExtname(new)
}
delete(syms.hash[v], old)

Expand Down

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