[dev.link] cmd/internal/goobj: add index to symbol name for indexed symbols

With old object files, when objdump an object file which, for
example, contains a call of fmt.Fprintf, it shows a symbol
reference like

	R_CALL:fmt.Fprintf

With new object files, as the symbol reference is indexed, the
reference becomes

	R_CALL:fmt.#33

The object file does not contain information of what symbol #33
in the fmt package is.

To make this more useful, print the index when dumping the symbol
definitions. This way, when dumping the fmt package, e.g.
"go tool nm fmt.a", it will print

   6c705 T fmt.Fprintf#33

So we can find out what symbol #33 actually is.

Change-Id: I320776597d28615ce18dd0617c352d2b8180db49
Reviewed-on: https://go-review.googlesource.com/c/go/+/229246
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/src/cmd/objdump/objdump_test.go b/src/cmd/objdump/objdump_test.go
index c974d6707b..814cbf4564 100644
--- a/src/cmd/objdump/objdump_test.go
+++ b/src/cmd/objdump/objdump_test.go
@@ -14,6 +14,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"strings"
 	"testing"
@@ -284,9 +285,11 @@ 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(SB)",
-		"fmthello.go:6",
+		`main(#\d+)?\(SB\)`, // either new or old object file
+		`fmthello\.go:6`,
 	}
 
 	args = []string{
@@ -302,8 +305,9 @@ func TestDisasmGoobj(t *testing.T) {
 	text := string(out)
 	ok := true
 	for _, s := range need {
-		if !strings.Contains(text, s) {
-			t.Errorf("disassembly missing '%s'", s)
+		re := regexp.MustCompile(s)
+		if !re.MatchString(text) {
+			t.Errorf("disassembly missing %q", s)
 			ok = false
 		}
 	}