nmdump: support .dylib/.so

chore/nmdump/nmdump.go

@@ -33,7 +33,9 @@ func main() {
 	items, err := nm.List(os.Args[1])
 	check(err)
 	for _, item := range items {
-		fmt.Printf("\n%s:\n", item.File)
+		if item.File != "" {
+			fmt.Printf("\n%s:\n", item.File)
+		}
 		for _, sym := range item.Symbols {
 			if sym.FAddr {
 				fmt.Printf("%016x %c %s\n", sym.Addr, sym.Type, sym.Name)

x/nm/nm.go

@@ -87,10 +87,14 @@ func (p *Cmd) List(arfile string) (items []*ObjectFile, err error) {
 }
 
 func listOutput(data []byte) (items []*ObjectFile, err error) {
-	var item *ObjectFile
-	var sep = []byte{'\n'}
-	for _, line := range bytes.Split(data, sep) {
+	sep := []byte{'\n'}
+	item := &ObjectFile{}
+	lines := bytes.Split(data, sep)
+	for _, line := range lines {
 		if len(line) == 0 {
+			if item.File == "" && len(item.Symbols) > 0 {
+				items = append(items, item)
+			}
 			item = nil
 			continue
 		}