[dev.link] cmd/link: remove Gotype and File fields from sym.Symbol

Remove the 'Gotype' field from sym.Symbol, as it is now no longer
used. Store the loader.Sym for a symbol as a field in sym.Symbol
("SymIdx"). Then remove sym.Symbol 'File' field, and replace the field
accesses in question with calls into the loader instead.

Change-Id: I01c5504425006b8d3fe77fac2b69a86e198c7a5a
Reviewed-on: https://go-review.googlesource.com/c/go/+/230304
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

src/cmd/link/internal/ld/lib.go

@@ -2911,6 +2911,13 @@ func (ctxt *Link) loadlibfull(symGroupType []sym.SymKind) {
 	}
 }
 
+func symPkg(ctxt *Link, s *sym.Symbol) string {
+	if s == nil {
+		return ""
+	}
+	return ctxt.loader.SymPkg(loader.Sym(s.SymIdx))
+}
+
 func (ctxt *Link) dumpsyms() {
 	for _, s := range ctxt.loader.Syms {
 		if s == nil {

src/cmd/link/internal/ld/xcoff.go

@@ -783,19 +783,19 @@ func (f *xcoffFile) writeSymbolFunc(ctxt *Link, x *sym.Symbol) []xcoffSym {
 		// Trampoline don't have a FILE so there are considered
 		// in the current file.
 		// Same goes for runtime.text.X symbols.
-	} else if x.File == "" { // Undefined global symbol
+	} else if symPkg(ctxt, x) == "" { // Undefined global symbol
 		// If this happens, the algorithm must be redone.
 		if currSymSrcFile.name != "" {
 			Exitf("undefined global symbol found inside another file")
 		}
 	} else {
 		// Current file has changed. New C_FILE, C_DWARF, etc must be generated.
-		if currSymSrcFile.name != x.File {
+		if currSymSrcFile.name != symPkg(ctxt, x) {
 			if ctxt.LinkMode == LinkInternal {
 				// update previous file values
 				xfile.updatePreviousFile(ctxt, false)
-				currSymSrcFile.name = x.File
-				f.writeSymbolNewFile(ctxt, x.File, uint64(x.Value), xfile.getXCOFFscnum(x.Sect))
+				currSymSrcFile.name = symPkg(ctxt, x)
+				f.writeSymbolNewFile(ctxt, symPkg(ctxt, x), uint64(x.Value), xfile.getXCOFFscnum(x.Sect))
 			} else {
 				// With external linking, ld will crash if there is several
 				// .FILE and DWARF debugging enable, somewhere during
@@ -805,7 +805,7 @@ func (f *xcoffFile) writeSymbolFunc(ctxt *Link, x *sym.Symbol) []xcoffSym {
 				// TODO(aix); remove once ld has been fixed or the triggering
 				// relocation has been found and fixed.
 				if currSymSrcFile.name == "" {
-					currSymSrcFile.name = x.File
+					currSymSrcFile.name = symPkg(ctxt, x)
 					f.writeSymbolNewFile(ctxt, "go_functions", uint64(x.Value), xfile.getXCOFFscnum(x.Sect))
 				}
 			}
@@ -866,7 +866,7 @@ func putaixsym(ctxt *Link, x *sym.Symbol, str string, t SymbolType, addr int64)
 		return
 
 	case TextSym:
-		if x.File != "" || strings.Contains(x.Name, "-tramp") || strings.HasPrefix(x.Name, "runtime.text.") {
+		if symPkg(ctxt, x) != "" || strings.Contains(x.Name, "-tramp") || strings.HasPrefix(x.Name, "runtime.text.") {
 			// Function within a file
 			syms = xfile.writeSymbolFunc(ctxt, x)
 		} else {

src/cmd/link/internal/loader/loader.go

@@ -1992,14 +1992,6 @@ func (l *Loader) LoadFull(arch *sys.Arch, syms *sym.Symbols) {
 		s.Version = int16(pp.ver)
 		s.Type = pp.kind
 		s.Size = pp.size
-		if pp.gotype != 0 {
-			s.Gotype = l.Syms[pp.gotype]
-		}
-		if f, ok := l.symPkg[i]; ok {
-			s.File = f
-		} else if pp.objidx != 0 {
-			s.File = l.objs[pp.objidx].r.unit.Lib.Pkg
-		}
 
 		// Copy relocations
 		batch := l.relocBatch
@@ -2161,22 +2153,7 @@ func (l *Loader) PropagateLoaderChangesToSymbols(toconvert []Sym, anonVerReplace
 			relfix = true
 		}
 
-		// For 'new' symbols, copy other content (such as Gotype,
-		// sym file, relocations, etc).
-		if isnew {
-			if gt := l.SymGoType(cand); gt != 0 {
-				s.Gotype = l.Syms[gt]
-			}
-			if f, ok := l.symPkg[cand]; ok {
-				s.File = f
-			} else {
-				r, _ := l.toLocal(cand)
-				if r != nil && r != l.extReader {
-					s.File = l.SymPkg(cand)
-				}
-			}
-		}
-
+		// For 'new' symbols, copy other content.
 		if relfix {
 			relocfixup = append(relocfixup, cand)
 		}
@@ -2276,6 +2253,7 @@ func (l *Loader) installSym(i Sym, s *sym.Symbol) {
 		panic("sym already present in installSym")
 	}
 	l.Syms[i] = s
+	s.SymIdx = sym.LoaderSym(i)
 }
 
 // addNewSym adds a new sym.Symbol to the i-th index in the list of symbols.
@@ -2554,11 +2532,6 @@ func (l *Loader) CreateStaticSym(name string) Sym {
 }
 
 func loadObjFull(l *Loader, r *oReader) {
-	resolveSymRef := func(s goobj2.SymRef) *sym.Symbol {
-		i := l.resolve(r, s)
-		return l.Syms[i]
-	}
-
 	for i, n := 0, r.NSym()+r.NNonpkgdef(); i < n; i++ {
 		// A symbol may be a dup or overwritten. In this case, its
 		// content will actually be provided by a different object
@@ -2595,12 +2568,7 @@ func loadObjFull(l *Loader, r *oReader) {
 		for j := range auxs {
 			a := &auxs[j]
 			switch a.Type() {
-			case goobj2.AuxGotype:
-				typ := resolveSymRef(a.Sym())
-				if typ != nil {
-					s.Gotype = typ
-				}
-			case goobj2.AuxFuncInfo, goobj2.AuxFuncdata:
+			case goobj2.AuxFuncInfo, goobj2.AuxFuncdata, goobj2.AuxGotype:
 				// already handled
 			case goobj2.AuxDwarfInfo, goobj2.AuxDwarfLoc, goobj2.AuxDwarfRanges, goobj2.AuxDwarfLines:
 				// ignored for now
@@ -2609,7 +2577,6 @@ func loadObjFull(l *Loader, r *oReader) {
 			}
 		}
 
-		s.File = r.pkgprefix[:len(r.pkgprefix)-1]
 		if s.Size < int64(size) {
 			s.Size = int64(size)
 		}

src/cmd/link/internal/sym/sizeof_test.go

@@ -21,7 +21,7 @@ func TestSizeof(t *testing.T) {
 		_32bit uintptr     // size on 32bit platforms
 		_64bit uintptr     // size on 64bit platforms
 	}{
-		{Symbol{}, 104, 168},
+		{Symbol{}, 96, 152},
 	}
 
 	for _, tt := range tests {

src/cmd/link/internal/sym/symbol.go

@@ -27,8 +27,7 @@ type Symbol struct {
 	Size        int64
 	Sub         *Symbol
 	Outer       *Symbol
-	Gotype      *Symbol
-	File        string // actually package!
+	SymIdx      LoaderSym
 	auxinfo     *AuxSymbol
 	Sect        *Section
 	Unit        *CompilationUnit