[dev.cc] cmd/5g etc: code cleanup: delay var decls and eliminate dead code

Ran rsc.io/grind rev 6f0e601 on the source files.

The cleanups move var declarations as close to the use
as possible, splitting disjoint uses of the var into separate
variables. They also remove dead code (especially in
func sudoaddable), which helps with the var moving.

There's more cleanup to come, but this alone cuts the
time spent compiling html/template on my 2013 MacBook Pro
from 3.1 seconds to 2.3 seconds.

Change-Id: I4de499f47b1dd47a560c310bbcde6b08d425cfd6
Reviewed-on: https://go-review.googlesource.com/5637
Reviewed-by: Rob Pike <r@golang.org>

1 files changed, 20 insertions, 33 deletions

diff --git a/src/cmd/internal/obj/obj.go b/src/cmd/internal/obj/obj.go
index 214d9cae8b..05902e2e33 100644
--- a/src/cmd/internal/obj/obj.go
+++ b/src/cmd/internal/obj/obj.go
@@ -25,12 +25,8 @@ func Linklinefmt(ctxt *Link, lno0 int, showAll, showFullPath bool) string {
 	lno := int32(lno0)
 	lno1 := lno
 	var d int32
-	var i int
-	var n int
-	var h *Hist
-	n = 0
-	var fp string
-	for h = ctxt.Hist; h != nil; h = h.Link {
+	n := 0
+	for h := ctxt.Hist; h != nil; h = h.Link {
 		if h.Offset < 0 {
 			continue
 		}
@@ -65,7 +61,8 @@ func Linklinefmt(ctxt *Link, lno0 int, showAll, showFullPath bool) string {
 	if n > int(HISTSZ) {
 		n = int(HISTSZ)
 	}
-	for i = n - 1; i >= 0; i-- {
+	var fp string
+	for i := n - 1; i >= 0; i-- {
 		if i != n-1 {
 			if !showAll {
 				break
@@ -93,12 +90,12 @@ func Linklinefmt(ctxt *Link, lno0 int, showAll, showFullPath bool) string {
 // For portability, we allow ASCII case folding, so that haspathprefix("a/b/c", "A/B") is true.
 // Similarly, we allow slash folding, so that haspathprefix("a/b/c", "a\\b") is true.
 func haspathprefix(s string, t string) bool {
-	var i int
-	var cs int
-	var ct int
 	if len(t) > len(s) {
 		return false
 	}
+	var i int
+	var cs int
+	var ct int
 	for i = 0; i < len(t); i++ {
 		cs = int(s[i])
 		ct = int(t[i])
@@ -131,17 +128,10 @@ func linkgetline(ctxt *Link, line int32, f **LSym, l *int32) {
 		line *Hist
 		ldel int32
 	}
-	var lno int32
 	var d int32
-	var dlno int32
-	var n int
-	var h *Hist
-	var buf string
-	var buf1 string
-	var file string
-	lno = int32(line)
-	n = 0
-	for h = ctxt.Hist; h != nil; h = h.Link {
+	lno := int32(line)
+	n := 0
+	for h := ctxt.Hist; h != nil; h = h.Link {
 		if h.Offset < 0 {
 			continue
 		}
@@ -182,6 +172,8 @@ func linkgetline(ctxt *Link, line int32, f **LSym, l *int32) {
 		return
 	}
 	n--
+	var dlno int32
+	var file string
 	if a[n].line != nil {
 		file = a[n].line.Name
 		dlno = a[n].ldel - 1
@@ -189,6 +181,7 @@ func linkgetline(ctxt *Link, line int32, f **LSym, l *int32) {
 		file = a[n].incl.Name
 		dlno = a[n].idel - 1
 	}
+	var buf string
 	if filepath.IsAbs(file) || strings.HasPrefix(file, "<") {
 		buf = fmt.Sprintf("%s", file)
 	} else {
@@ -199,14 +192,14 @@ func linkgetline(ctxt *Link, line int32, f **LSym, l *int32) {
 		if len(buf) == len(ctxt.Trimpath) {
 			buf = "??"
 		} else {
-			buf1 = fmt.Sprintf("%s", buf[len(ctxt.Trimpath)+1:])
+			buf1 := fmt.Sprintf("%s", buf[len(ctxt.Trimpath)+1:])
 			if buf1[0] == '\x00' {
 				buf1 = "??"
 			}
 			buf = buf1
 		}
 	} else if ctxt.Goroot_final != "" && haspathprefix(buf, ctxt.Goroot) {
-		buf1 = fmt.Sprintf("%s%s", ctxt.Goroot_final, buf[len(ctxt.Goroot):])
+		buf1 := fmt.Sprintf("%s%s", ctxt.Goroot_final, buf[len(ctxt.Goroot):])
 		buf = buf1
 	}
 	lno -= dlno
@@ -215,8 +208,6 @@ func linkgetline(ctxt *Link, line int32, f **LSym, l *int32) {
 }
 
 func Linklinehist(ctxt *Link, lineno int, f string, offset int) {
-	var h *Hist
-
 	if false { // debug['f']
 		if f != "" {
 			if offset != 0 {
@@ -229,7 +220,7 @@ func Linklinehist(ctxt *Link, lineno int, f string, offset int) {
 		}
 	}
 
-	h = new(Hist)
+	h := new(Hist)
 	*h = Hist{}
 	h.Name = f
 	h.Line = int32(lineno)
@@ -248,12 +239,10 @@ func Linklinehist(ctxt *Link, lineno int, f string, offset int) {
 func Linkprfile(ctxt *Link, line int) {
 	l := int32(line)
 	var i int
-	var n int
 	var a [HISTSZ]Hist
-	var h *Hist
 	var d int32
-	n = 0
-	for h = ctxt.Hist; h != nil; h = h.Link {
+	n := 0
+	for h := ctxt.Hist; h != nil; h = h.Link {
 		if l < h.Line {
 			break
 		}
@@ -286,7 +275,7 @@ func Linkprfile(ctxt *Link, line int) {
 	if n > HISTSZ {
 		n = HISTSZ
 	}
-	for i = 0; i < n; i++ {
+	for i := 0; i < n; i++ {
 		fmt.Printf("%s:%d ", a[i].Name, int(l-a[i].Line+a[i].Offset+1))
 	}
 }
@@ -295,9 +284,7 @@ func Linkprfile(ctxt *Link, line int) {
  * start a new Prog list.
  */
 func Linknewplist(ctxt *Link) *Plist {
-	var pl *Plist
-
-	pl = new(Plist)
+	pl := new(Plist)
 	*pl = Plist{}
 	if ctxt.Plist == nil {
 		ctxt.Plist = pl