[dev.link] cmd/internal/goobj2: provide accessor methods for flags

Per Jeremy's comment in CL 199643. This makes the code read
better.

Change-Id: If270aecd712a27fb52e3faf5a4339200327d9ffe
Reviewed-on: https://go-review.googlesource.com/c/go/+/201023
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

src/cmd/internal/goobj/readnew.go

@@ -87,7 +87,7 @@ func (r *objReader) readNew() {
 		sym := Sym{
 			SymID: symID,
 			Kind:  objabi.SymKind(osym.Type),
-			DupOK: osym.Flag&goobj2.SymFlagDupok != 0,
+			DupOK: osym.Dupok(),
 			Size:  int64(osym.Siz),
 			Data:  Data{int64(start + dataOff), siz},
 		}
@@ -145,8 +145,8 @@ func (r *objReader) readNew() {
 			Args:     int64(info.Args),
 			Frame:    int64(info.Locals),
 			NoSplit:  info.NoSplit != 0,
-			Leaf:     osym.Flag&goobj2.SymFlagLeaf != 0,
-			TopFrame: osym.Flag&goobj2.SymFlagTopFrame != 0,
+			Leaf:     osym.Leaf(),
+			TopFrame: osym.TopFrame(),
 			PCSP:     Data{int64(pcdataBase + info.Pcsp), int64(info.Pcfile - info.Pcsp)},
 			PCFile:   Data{int64(pcdataBase + info.Pcfile), int64(info.Pcline - info.Pcfile)},
 			PCLine:   Data{int64(pcdataBase + info.Pcline), int64(info.Pcinline - info.Pcline)},

src/cmd/internal/goobj2/objfile.go

@@ -220,6 +220,15 @@ func (s *Sym) Size() int {
 	return 4 + 2 + 1 + 1 + 4
 }
 
+func (s *Sym) Dupok() bool         { return s.Flag&SymFlagDupok != 0 }
+func (s *Sym) Local() bool         { return s.Flag&SymFlagLocal != 0 }
+func (s *Sym) Typelink() bool      { return s.Flag&SymFlagTypelink != 0 }
+func (s *Sym) Leaf() bool          { return s.Flag&SymFlagLeaf != 0 }
+func (s *Sym) CFunc() bool         { return s.Flag&SymFlagCFunc != 0 }
+func (s *Sym) ReflectMethod() bool { return s.Flag&SymFlagReflectMethod != 0 }
+func (s *Sym) Shared() bool        { return s.Flag&SymFlagShared != 0 }
+func (s *Sym) TopFrame() bool      { return s.Flag&SymFlagTopFrame != 0 }
+
 // Symbol reference.
 type SymRef struct {
 	PkgIdx uint32

src/cmd/link/internal/objfile/objfile2.go

@@ -155,7 +155,7 @@ func (l *Loader) AddSym(name string, ver int, i Sym, r *oReader, dupok bool, typ
 			oldsym := goobj2.Sym{}
 			oldsym.Read(oldr.Reader, oldr.SymOff(li))
 			oldtyp := sym.AbiSymKindToSymKind[objabi.SymKind(oldsym.Type)]
-			if oldsym.Flag&goobj2.SymFlagDupok == 0 && !((oldtyp == sym.SDATA || oldtyp == sym.SNOPTRDATA || oldtyp == sym.SBSS || oldtyp == sym.SNOPTRBSS) && oldr.DataSize(li) == 0) { // only allow overwriting 0-sized data symbol
+			if !oldsym.Dupok() && !((oldtyp == sym.SDATA || oldtyp == sym.SNOPTRDATA || oldtyp == sym.SBSS || oldtyp == sym.SNOPTRBSS) && oldr.DataSize(li) == 0) { // only allow overwriting 0-sized data symbol
 				log.Fatalf("duplicated definition of symbol " + name)
 			}
 			l.overwrite[oldi] = i
@@ -415,7 +415,7 @@ func LoadNew(l *Loader, arch *sys.Arch, syms *sym.Symbols, f *bio.Reader, lib *s
 			continue // don't add unnamed aux symbol
 		}
 		v := abiToVer(osym.ABI, localSymVersion)
-		dupok := osym.Flag&goobj2.SymFlagDupok != 0
+		dupok := osym.Dupok()
 		l.AddSym(name, v, istart+Sym(i), or, dupok, sym.AbiSymKindToSymKind[objabi.SymKind(osym.Type)])
 	}
 
@@ -566,7 +566,7 @@ func loadObjFull(l *Loader, r *oReader) {
 			continue
 		}
 		ver := abiToVer(osym.ABI, r.version)
-		dupok := osym.Flag&goobj2.SymFlagDupok != 0
+		dupok := osym.Dupok()
 		if dupsym := l.symsByName[nameVer{name, ver}]; dupsym != istart+Sym(i) {
 			if dupok && l.Reachable.Has(dupsym) {
 				// A dupok symbol is resolved to another package. We still need
@@ -589,8 +589,8 @@ func loadObjFull(l *Loader, r *oReader) {
 			panic("name mismatch")
 		}
 
-		local := osym.Flag&goobj2.SymFlagLocal != 0
-		makeTypelink := osym.Flag&goobj2.SymFlagTypelink != 0
+		local := osym.Local()
+		makeTypelink := osym.Typelink()
 		size := osym.Siz
 
 		// Symbol data
@@ -694,13 +694,13 @@ func loadObjFull(l *Loader, r *oReader) {
 		if info.NoSplit != 0 {
 			s.Attr |= sym.AttrNoSplit
 		}
-		if osym.Flag&goobj2.SymFlagReflectMethod != 0 {
+		if osym.ReflectMethod() {
 			s.Attr |= sym.AttrReflectMethod
 		}
-		if osym.Flag&goobj2.SymFlagShared != 0 {
+		if osym.Shared() {
 			s.Attr |= sym.AttrShared
 		}
-		if osym.Flag&goobj2.SymFlagTopFrame != 0 {
+		if osym.TopFrame() {
 			s.Attr |= sym.AttrTopFrame
 		}