cmd/internal: rewrite fmt.Sprintf("%s", x) to x

Change-Id: I764933f4928bb9d0d119fbfe44a193ce1449b61e
Reviewed-on: https://go-review.googlesource.com/6791Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

src/cmd/internal/ld/go.go

@@ -694,19 +694,19 @@ func deadcode() {
 	}
 
 	// record field tracking references
-	fmt_ := ""
-
+	var buf bytes.Buffer
 	var p *LSym
 	for s := Ctxt.Allsym; s != nil; s = s.Allsym {
 		if strings.HasPrefix(s.Name, "go.track.") {
 			s.Special = 1 // do not lay out in data segment
 			s.Hide = 1
 			if s.Reachable {
-				fmt_ += fmt.Sprintf("%s", s.Name[9:])
+				buf.WriteString(s.Name[9:])
 				for p = s.Reachparent; p != nil; p = p.Reachparent {
-					fmt_ += fmt.Sprintf("\t%s", p.Name)
+					buf.WriteString("\t")
+					buf.WriteString(p.Name)
 				}
-				fmt_ += fmt.Sprintf("\n")
+				buf.WriteString("\n")
 			}
 
 			s.Type = SCONST
@@ -721,7 +721,7 @@ func deadcode() {
 	if !s.Reachable {
 		return
 	}
-	addstrdata(tracksym, fmt_)
+	addstrdata(tracksym, buf.String())
 }
 
 func doweak() {

src/cmd/internal/obj/i386/list8.go

@@ -155,7 +155,7 @@ func init() {
 
 func Rconv(r int) string {
 	if r >= REG_AL && r-REG_AL < len(Register) {
-		return fmt.Sprintf("%s", Register[r-REG_AL])
+		return Register[r-REG_AL]
 	}
 	return fmt.Sprintf("Rgok(%d)", r-obj.RBase386)
 }

src/cmd/internal/obj/obj.go

@@ -183,16 +183,16 @@ func linkgetline(ctxt *Link, line int32, f **LSym, l *int32) {
 	}
 	var buf string
 	if filepath.IsAbs(file) || strings.HasPrefix(file, "<") {
-		buf = fmt.Sprintf("%s", file)
+		buf = file
 	} else {
-		buf = fmt.Sprintf("%s/%s", ctxt.Pathname, file)
+		buf = ctxt.Pathname + "/" + file
 	}
 	// Remove leading ctxt->trimpath, or else rewrite $GOROOT to $GOROOT_FINAL.
 	if ctxt.Trimpath != "" && haspathprefix(buf, ctxt.Trimpath) {
 		if len(buf) == len(ctxt.Trimpath) {
 			buf = "??"
 		} else {
-			buf1 := fmt.Sprintf("%s", buf[len(ctxt.Trimpath)+1:])
+			buf1 := buf[len(ctxt.Trimpath)+1:]
 			if buf1[0] == '\x00' {
 				buf1 = "??"
 			}

src/cmd/internal/obj/x86/list6.go

@@ -211,7 +211,7 @@ func init() {
 
 func Rconv(r int) string {
 	if REG_AL <= r && r-REG_AL < len(Register) {
-		return fmt.Sprintf("%s", Register[r-REG_AL])
+		return Register[r-REG_AL]
 	}
 	return fmt.Sprintf("Rgok(%d)", r-obj.RBaseAMD64)
 }