cmd/internal/obj/x86: clean up part of span6

Passes toolstash -cmp.

Change-Id: I38eb507de2e9dc2cf01822e420bf31a91fb1b720
Reviewed-on: https://go-review.googlesource.com/20766
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/internal/obj/x86/asm6.go b/src/cmd/internal/obj/x86/asm6.go
index 481b08b304d2b72665de8b00559ec93de695a682..b06439ecf15540c7ec694503feeb152bc061be2a 100644 (file)
--- a/src/cmd/internal/obj/x86/asm6.go
+++ b/src/cmd/internal/obj/x86/asm6.go
@@ -32,6 +32,7 @@ package x86
 
 import (
        "cmd/internal/obj"
+       "encoding/binary"
        "fmt"
        "log"
        "strings"
@@ -1770,7 +1771,6 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
                instinit()
        }
 
-       var v int32
        for p := ctxt.Cursym.Text; p != nil; p = p.Link {
                if p.To.Type == obj.TYPE_BRANCH {
                        if p.Pcond == nil {
@@ -1780,7 +1780,7 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
                if p.As == AADJSP {
                        p.To.Type = obj.TYPE_REG
                        p.To.Reg = REG_SP
-                       v = int32(-p.From.Offset)
+                       v := int32(-p.From.Offset)
                        p.From.Offset = int64(v)
                        p.As = spadjop(ctxt, p, AADDL, AADDQ)
                        if v < 0 {
@@ -1807,7 +1807,7 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
                if p.As == AADJSP {
                        p.To.Type = obj.TYPE_REG
                        p.To.Reg = REG_SP
-                       v = int32(-p.From.Offset)
+                       v := int32(-p.From.Offset)
                        p.From.Offset = int64(v)
                        p.As = spadjop(ctxt, p, AADDL, AADDQ)
                        if v < 0 {
@@ -1823,28 +1823,22 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
        }
 
        n := 0
-       var bp []byte
        var c int32
-       var i int
-       var loop int32
-       var m int
-       var p *obj.Prog
        errors := ctxt.Errors
+       var deferreturn *obj.LSym
+       if ctxt.Headtype == obj.Hnacl {
+               deferreturn = obj.Linklookup(ctxt, "runtime.deferreturn", 0)
+       }
        for {
-               loop = 0
-               for i = 0; i < len(s.R); i++ {
+               loop := int32(0)
+               for i := range s.R {
                        s.R[i] = obj.Reloc{}
                }
                s.R = s.R[:0]
                s.P = s.P[:0]
                c = 0
-               for p = s.Text; p != nil; p = p.Link {
+               for p := s.Text; p != nil; p = p.Link {
                        if ctxt.Headtype == obj.Hnacl && p.Isize > 0 {
-                               var deferreturn *obj.LSym
-
-                               if deferreturn == nil {
-                                       deferreturn = obj.Linklookup(ctxt, "runtime.deferreturn", 0)
-                               }
 
                                // pad everything to avoid crossing 32-byte boundary
                                if c>>5 != (c+int32(p.Isize)-1)>>5 {
@@ -1881,7 +1875,7 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
 
                        if (p.Back&4 != 0) && c&(LoopAlign-1) != 0 {
                                // pad with NOPs
-                               v = -c & (LoopAlign - 1)
+                               v := -c & (LoopAlign - 1)
 
                                if v <= MaxLoopPad {
                                        obj.Symgrow(ctxt, s, int64(c)+int64(v))
@@ -1894,7 +1888,7 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
 
                        // process forward jumps to p
                        for q = p.Rel; q != nil; q = q.Forwd {
-                               v = int32(p.Pc - (q.Pc + int64(q.Isize)))
+                               v := int32(p.Pc - (q.Pc + int64(q.Isize)))
                                if q.Back&2 != 0 { // short
                                        if v > 127 {
                                                loop++
@@ -1907,14 +1901,7 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
                                                s.P[q.Pc+1] = byte(v)
                                        }
                                } else {
-                                       bp = s.P[q.Pc+int64(q.Isize)-4:]
-                                       bp[0] = byte(v)
-                                       bp = bp[1:]
-                                       bp[0] = byte(v >> 8)
-                                       bp = bp[1:]
-                                       bp[0] = byte(v >> 16)
-                                       bp = bp[1:]
-                                       bp[0] = byte(v >> 24)
+                                       binary.LittleEndian.PutUint32(s.P[q.Pc+int64(q.Isize)-4:], uint32(v))
                                }
                        }
 
@@ -1922,7 +1909,7 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
 
                        p.Pc = int64(c)
                        asmins(ctxt, p)
-                       m = -cap(ctxt.Andptr) + cap(ctxt.And[:])
+                       m := -cap(ctxt.Andptr) + cap(ctxt.And[:])
                        if int(p.Isize) != m {
                                p.Isize = uint8(m)
                                loop++
@@ -1952,7 +1939,7 @@ func span6(ctxt *obj.Link, s *obj.LSym) {
 
        // Pad functions with trap instruction, to catch invalid jumps
        if c&(FuncAlign-1) != 0 {
-               v = -c & (FuncAlign - 1)
+               v := -c & (FuncAlign - 1)
                obj.Symgrow(ctxt, s, int64(c)+int64(v))
                for i := c; i < c+v; i++ {
                        // 0xCC is INT $3 - breakpoint instruction