Revert "cmd/internal/goobj: add index to symbol name for indexed symbols"

This reverts CL 229246.

For new indexed object files, in CL 229246 we added symbol index
to tools (nm, objdump) output. This affects external tools that
parse those outputs. And the added index doesn't look very nice.
In this release we take it out. For future releases we may
introduce a flag to tools (nm, objdump) and optionally dump the
symbol index.

For refererenced (not defined) indexed symbols, currently the
symbol is still referenced only by index, not by name. The next
CL will make the object file self-contained, so tools can dump
the symbol names properly (as before).

For #38875.

Change-Id: I07375e85a8e826e15c82fa452d11f0eaf8535a00
Reviewed-on: https://go-review.googlesource.com/c/go/+/236167


Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

src/cmd/internal/goobj/goobj_test.go

@@ -17,7 +17,6 @@ import (
 	"os/exec"
 	"path/filepath"
 	"runtime"
-	"strings"
 	"testing"
 )
 
@@ -151,14 +150,6 @@ func buildGoobj() error {
 	return nil
 }
 
-// Check that a symbol has a given name, accepting both
-// new and old objects.
-// TODO(go115newobj): remove.
-func matchSymName(symname, want string) bool {
-	return symname == want ||
-		strings.HasPrefix(symname, want+"#") // new style, with index
-}
-
 func TestParseGoobj(t *testing.T) {
 	path := go1obj
 
@@ -177,7 +168,7 @@ func TestParseGoobj(t *testing.T) {
 	}
 	var found bool
 	for _, s := range p.Syms {
-		if matchSymName(s.Name, "mypkg.go1") {
+		if s.Name == "mypkg.go1" {
 			found = true
 			break
 		}
@@ -206,10 +197,10 @@ func TestParseArchive(t *testing.T) {
 	var found1 bool
 	var found2 bool
 	for _, s := range p.Syms {
-		if matchSymName(s.Name, "mypkg.go1") {
+		if s.Name == "mypkg.go1" {
 			found1 = true
 		}
-		if matchSymName(s.Name, "mypkg.go2") {
+		if s.Name == "mypkg.go2" {
 			found2 = true
 		}
 	}
@@ -242,10 +233,10 @@ func TestParseCGOArchive(t *testing.T) {
 	var found1 bool
 	var found2 bool
 	for _, s := range p.Syms {
-		if matchSymName(s.Name, "mycgo.go1") {
+		if s.Name == "mycgo.go1" {
 			found1 = true
 		}
-		if matchSymName(s.Name, "mycgo.go2") {
+		if s.Name == "mycgo.go2" {
 			found2 = true
 		}
 	}

src/cmd/internal/goobj/readnew.go

@@ -58,10 +58,8 @@ func (r *objReader) readNew() {
 		case goobj2.PkgIdxSelf:
 			i = int(s.SymIdx)
 		default:
-			// Symbol from other package, referenced by index.
-			// We don't know the name. Use index.
 			pkg := pkglist[p]
-			return SymID{fmt.Sprintf("%s.#%d", pkg, s.SymIdx), 0}
+			return SymID{fmt.Sprintf("%s.<#%d>", pkg, s.SymIdx), 0}
 		}
 		sym := rr.Sym(i)
 		return SymID{sym.Name(rr), abiToVer(sym.ABI())}
@@ -72,7 +70,6 @@ func (r *objReader) readNew() {
 	// Symbols
 	pcdataBase := start + rr.PcdataBase()
 	n := rr.NSym() + rr.NNonpkgdef() + rr.NNonpkgref()
-	npkgdef := rr.NSym()
 	ndef := rr.NSym() + rr.NNonpkgdef()
 	for i := 0; i < n; i++ {
 		osym := rr.Sym(i)
@@ -83,10 +80,6 @@ func (r *objReader) readNew() {
 		// prefix for the package in which the object file has been found.
 		// Expand it.
 		name := strings.ReplaceAll(osym.Name(rr), `"".`, r.pkgprefix)
-		if i < npkgdef {
-			// Indexed symbol. Attach index to the name.
-			name += fmt.Sprintf("#%d", i)
-		}
 		symID := SymID{Name: name, Version: abiToVer(osym.ABI())}
 		r.p.SymRefs = append(r.p.SymRefs, symID)
 

src/cmd/nm/nm_test.go

@@ -315,7 +315,7 @@ func testGoLib(t *testing.T, iscgo bool) {
 		}
 		for i := range syms {
 			sym := &syms[i]
-			if sym.Type == typ && matchSymName(name, sym.Name) && sym.CSym == csym {
+			if sym.Type == typ && sym.Name == name && sym.CSym == csym {
 				if sym.Found {
 					t.Fatalf("duplicate symbol %s %s", sym.Type, sym.Name)
 				}
@@ -334,14 +334,6 @@ func TestGoLib(t *testing.T) {
 	testGoLib(t, false)
 }
 
-// Check that a symbol has a given name, accepting both
-// new and old objects.
-// TODO(go115newobj): remove.
-func matchSymName(symname, want string) bool {
-	return symname == want ||
-		strings.HasPrefix(symname, want+"#") // new style, with index
-}
-
 const testexec = `
 package main
 

src/cmd/objdump/objdump_test.go

@@ -14,7 +14,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"regexp"
 	"runtime"
 	"strings"
 	"testing"
@@ -285,11 +284,9 @@ func TestDisasmGoobj(t *testing.T) {
 	if err != nil {
 		t.Fatalf("go tool compile fmthello.go: %v\n%s", err, out)
 	}
-
-	// TODO(go115newobj): drop old object file support.
 	need := []string{
-		`main(#\d+)?\(SB\)`, // either new or old object file
-		`fmthello\.go:6`,
+		"main(SB)",
+		"fmthello.go:6",
 	}
 
 	args = []string{
@@ -305,9 +302,8 @@ func TestDisasmGoobj(t *testing.T) {
 	text := string(out)
 	ok := true
 	for _, s := range need {
-		re := regexp.MustCompile(s)
-		if !re.MatchString(text) {
-			t.Errorf("disassembly missing %q", s)
+		if !strings.Contains(text, s) {
+			t.Errorf("disassembly missing '%s'", s)
 			ok = false
 		}
 	}