cmd/link: split out Extname into cold portion of sym.Symbol

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 <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
index 4ecbff86a9c5dd29507bbd72062ccaada8c057d9..f61a290e42d2c7d07c69b8c4e534264e819094d7 100644 (file)
--- a/src/cmd/link/internal/ld/elf.go
+++ b/src/cmd/link/internal/ld/elf.go
@@ -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)
@@ -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 */
@@ -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)))
 

diff --git a/src/cmd/link/internal/ld/go.go b/src/cmd/link/internal/ld/go.go
index 06ee6968c6804b6fb4a3a76ac487e273bcae41c5..f2dd799922e50df3e5082b6f5dd1ec7bfaddfc92 100644 (file)
--- a/src/cmd/link/internal/ld/go.go
+++ b/src/cmd/link/internal/ld/go.go
@@ -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
@@ -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
                        }
@@ -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 {

diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index ba03cb707b84f74d8115ddee45c6be7a15c53d85..511cdd891a283e42d40d982ed7d4391059cab883 100644 (file)
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -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
@@ -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 {

diff --git a/src/cmd/link/internal/ld/macho.go b/src/cmd/link/internal/ld/macho.go
index 8315de5152d044746e81c55a9984a75c6f6969e7..b935814ff0a432a4232186139f646e7cd6e8ff77 100644 (file)
--- a/src/cmd/link/internal/ld/macho.go
+++ b/src/cmd/link/internal/ld/macho.go
@@ -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) {
@@ -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.") {
@@ -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

diff --git a/src/cmd/link/internal/ld/pe.go b/src/cmd/link/internal/ld/pe.go
index 0e60ef76d218f5401552415acc304a29c2eaee5d..db269c78e5313c14a43a2b902a60a44bc67db3d8 100644 (file)
--- a/src/cmd/link/internal/ld/pe.go
+++ b/src/cmd/link/internal/ld/pe.go
@@ -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
@@ -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)
@@ -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())
                }
        }
 
@@ -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
@@ -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 {
@@ -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
@@ -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))
 }

diff --git a/src/cmd/link/internal/sym/sizeof_test.go b/src/cmd/link/internal/sym/sizeof_test.go
index 2f2dfc79ed0d141806b9c81b44305c2f832b48c1..5d501bda499c2399ce2eab4f0c17f42e3e3eeb3e 100644 (file)
--- a/src/cmd/link/internal/sym/sizeof_test.go
+++ b/src/cmd/link/internal/sym/sizeof_test.go
@@ -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 {

diff --git a/src/cmd/link/internal/sym/symbol.go b/src/cmd/link/internal/sym/symbol.go
index ea0eb89e2bc99410685af4fe8b941cfd0c89d47c..245d62003baa1d289484f1f7237e88e057c0155c 100644 (file)
--- a/src/cmd/link/internal/sym/symbol.go
+++ b/src/cmd/link/internal/sym/symbol.go
@@ -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
@@ -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
@@ -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
 }
@@ -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.

diff --git a/src/cmd/link/internal/sym/symbols.go b/src/cmd/link/internal/sym/symbols.go
index f9405db185373b5d69ed3de029d86e01879641a1..7c6137c73c978af84598aed4000d2ea3706aa76f 100644 (file)
--- a/src/cmd/link/internal/sym/symbols.go
+++ b/src/cmd/link/internal/sym/symbols.go
@@ -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
 }
@@ -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)