cmd/internal/obj: index pcdata symbols in NumberSyms

When writing an object file, most symbols are indexed in
NumberSyms. Currently, pcdata symbols are indexed late and
separately. This is not really necessary, as pcdata symbols
already exist at the time of NumberSyms. Just do it there.

As pcdata symbols are laid out in the pclntab in a special way at
link time, distinguish them from other symbols in the content
hash. (In the old code this was partly achieved by indexing them
late.)

Change-Id: Ie9e721382b0af2cfb39350d031e2e66d79095a3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/352611
Trust: Cherry Mui <cherryyz@google.com>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

1 files changed, 8 insertions, 16 deletions

diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go
index 1a8a9635d6..030a02b499 100644
--- a/src/cmd/internal/obj/objfile.go
+++ b/src/cmd/internal/obj/objfile.go
@@ -391,7 +391,9 @@ func (w *writer) Hash(s *LSym) {
 // TODO: instead of duplicating them, have the compiler decide where symbols go.
 func contentHashSection(s *LSym) byte {
 	name := s.Name
-	if strings.HasPrefix(name, "type.") {
+	if s.IsPcdata() {
+		return 'P'
+	} else if strings.HasPrefix(name, "type.") {
 		return 'T'
 	}
 	return 0
@@ -655,16 +657,6 @@ func nAuxSym(s *LSym) int {
 func genFuncInfoSyms(ctxt *Link) {
 	infosyms := make([]*LSym, 0, len(ctxt.Text))
 	hashedsyms := make([]*LSym, 0, 4*len(ctxt.Text))
-	preparePcSym := func(s *LSym) *LSym {
-		if s == nil {
-			return s
-		}
-		s.PkgIdx = goobj.PkgIdxHashed
-		s.SymIdx = int32(len(hashedsyms) + len(ctxt.hasheddefs))
-		s.Set(AttrIndexed, true)
-		hashedsyms = append(hashedsyms, s)
-		return s
-	}
 	var b bytes.Buffer
 	symidx := int32(len(ctxt.defs))
 	for _, s := range ctxt.Text {
@@ -679,13 +671,13 @@ func genFuncInfoSyms(ctxt *Link) {
 			FuncFlag: fn.FuncFlag,
 		}
 		pc := &fn.Pcln
-		o.Pcsp = makeSymRef(preparePcSym(pc.Pcsp))
-		o.Pcfile = makeSymRef(preparePcSym(pc.Pcfile))
-		o.Pcline = makeSymRef(preparePcSym(pc.Pcline))
-		o.Pcinline = makeSymRef(preparePcSym(pc.Pcinline))
+		o.Pcsp = makeSymRef(pc.Pcsp)
+		o.Pcfile = makeSymRef(pc.Pcfile)
+		o.Pcline = makeSymRef(pc.Pcline)
+		o.Pcinline = makeSymRef(pc.Pcinline)
 		o.Pcdata = make([]goobj.SymRef, len(pc.Pcdata))
 		for i, pcSym := range pc.Pcdata {
-			o.Pcdata[i] = makeSymRef(preparePcSym(pcSym))
+			o.Pcdata[i] = makeSymRef(pcSym)
 		}
 		o.Funcdataoff = make([]uint32, len(pc.Funcdataoff))
 		for i, x := range pc.Funcdataoff {