[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>
diff --git a/src/cmd/internal/gc/popt.go b/src/cmd/internal/gc/popt.go
index 8a3601b..756f8eb 100644
--- a/src/cmd/internal/gc/popt.go
+++ b/src/cmd/internal/gc/popt.go
@@ -180,9 +180,6 @@
var noreturn_symlist [10]*Sym
func Noreturn(p *obj.Prog) bool {
- var s *Sym
- var i int
-
if noreturn_symlist[0] == nil {
noreturn_symlist[0] = Pkglookup("panicindex", Runtimepkg)
noreturn_symlist[1] = Pkglookup("panicslice", Runtimepkg)
@@ -197,11 +194,11 @@
if p.To.Node == nil {
return false
}
- s = ((p.To.Node).(*Node)).Sym
+ s := ((p.To.Node).(*Node)).Sym
if s == nil {
return false
}
- for i = 0; noreturn_symlist[i] != nil; i++ {
+ for i := 0; noreturn_symlist[i] != nil; i++ {
if s == noreturn_symlist[i] {
return true
}
@@ -219,9 +216,7 @@
/* what instruction does a JMP to p eventually land on? */
func chasejmp(p *obj.Prog, jmploop *int) *obj.Prog {
- var n int
-
- n = 0
+ n := 0
for p != nil && p.As == obj.AJMP && p.To.Type == obj.TYPE_BRANCH {
n++
if n > 10 {
@@ -244,9 +239,7 @@
/* mark all code reachable from firstp as alive */
func mark(firstp *obj.Prog) {
- var p *obj.Prog
-
- for p = firstp; p != nil; p = p.Link {
+ for p := firstp; p != nil; p = p.Link {
if p.Opt != dead {
break
}
@@ -261,18 +254,14 @@
}
func fixjmp(firstp *obj.Prog) {
- var jmploop int
- var p *obj.Prog
- var last *obj.Prog
-
if Debug['R'] != 0 && Debug['v'] != 0 {
fmt.Printf("\nfixjmp\n")
}
// pass 1: resolve jump to jump, mark all code as dead.
- jmploop = 0
+ jmploop := 0
- for p = firstp; p != nil; p = p.Link {
+ for p := firstp; p != nil; p = p.Link {
if Debug['R'] != 0 && Debug['v'] != 0 {
fmt.Printf("%v\n", p)
}
@@ -294,9 +283,9 @@
mark(firstp)
// pass 3: delete dead code (mostly JMPs).
- last = nil
+ last := (*obj.Prog)(nil)
- for p = firstp; p != nil; p = p.Link {
+ for p := firstp; p != nil; p = p.Link {
if p.Opt == dead {
if p.Link == nil && p.As == obj.ARET && last != nil && last.As != obj.ARET {
// This is the final ARET, and the code so far doesn't have one.
@@ -326,8 +315,8 @@
// pass 4: elide JMP to next instruction.
// only safe if there are no jumps to JMPs anymore.
if jmploop == 0 {
- last = nil
- for p = firstp; p != nil; p = p.Link {
+ last := (*obj.Prog)(nil)
+ for p := firstp; p != nil; p = p.Link {
if p.As == obj.AJMP && p.To.Type == obj.TYPE_BRANCH && p.To.U.Branch == p.Link {
if Debug['R'] != 0 && Debug['v'] != 0 {
fmt.Printf("del %v\n", p)
@@ -346,7 +335,7 @@
if Debug['R'] != 0 && Debug['v'] != 0 {
fmt.Printf("\n")
- for p = firstp; p != nil; p = p.Link {
+ for p := firstp; p != nil; p = p.Link {
fmt.Printf("%v\n", p)
}
fmt.Printf("\n")
@@ -374,20 +363,12 @@
// If size == 0, f->data will be nil.
func Flowstart(firstp *obj.Prog, newData func() interface{}) *Graph {
- var id int
- var nf int
- var f *Flow
- var f1 *Flow
- var start *Flow
- var last *Flow
- var graph *Graph
- var p *obj.Prog
var info ProgInfo
// Count and mark instructions to annotate.
- nf = 0
+ nf := 0
- for p = firstp; p != nil; p = p.Link {
+ for p := firstp; p != nil; p = p.Link {
p.Opt = nil // should be already, but just in case
Thearch.Proginfo(&info, p)
if info.Flags&Skip != 0 {
@@ -407,11 +388,12 @@
}
// Allocate annotations and assign to instructions.
- graph = new(Graph)
+ graph := new(Graph)
ff := make([]Flow, nf)
- start = &ff[0]
- id = 0
- for p = firstp; p != nil; p = p.Link {
+ start := &ff[0]
+ id := 0
+ var last *Flow
+ for p := firstp; p != nil; p = p.Link {
if p.Opt == nil {
continue
}
@@ -431,7 +413,9 @@
}
// Fill in pred/succ information.
- for f = start; f != nil; f = f.Link {
+ var f1 *Flow
+ var p *obj.Prog
+ for f := start; f != nil; f = f.Link {
p = f.Prog
Thearch.Proginfo(&info, p)
if info.Flags&Break == 0 {
@@ -465,9 +449,7 @@
}
func Flowend(graph *Graph) {
- var f *Flow
-
- for f = graph.Start; f != nil; f = f.Link {
+ for f := graph.Start; f != nil; f = f.Link {
f.Prog.Opt = nil
}
}
@@ -488,10 +470,8 @@
* recursively, all preds with a greater rpo number are in the loop
*/
func postorder(r *Flow, rpo2r []*Flow, n int32) int32 {
- var r1 *Flow
-
r.Rpo = 1
- r1 = r.S1
+ r1 := r.S1
if r1 != nil && r1.Rpo == 0 {
n = postorder(r1, rpo2r, n)
}
@@ -505,11 +485,10 @@
}
func rpolca(idom []int32, rpo1 int32, rpo2 int32) int32 {
- var t int32
-
if rpo1 == -1 {
return rpo2
}
+ var t int32
for rpo1 != rpo2 {
if rpo1 > rpo2 {
t = rpo2
@@ -537,9 +516,7 @@
}
func loophead(idom []int32, r *Flow) bool {
- var src int32
-
- src = r.Rpo
+ src := r.Rpo
if r.P1 != nil && doms(idom, src, r.P1.Rpo) {
return true
}
@@ -566,40 +543,34 @@
}
func flowrpo(g *Graph) {
- var r1 *Flow
- var i int32
- var d int32
- var me int32
- var nr int32
- var idom []int32
- var rpo2r []*Flow
-
g.Rpo = make([]*Flow, g.Num)
- idom = make([]int32, g.Num)
+ idom := make([]int32, g.Num)
- for r1 = g.Start; r1 != nil; r1 = r1.Link {
+ for r1 := g.Start; r1 != nil; r1 = r1.Link {
r1.Active = 0
}
- rpo2r = g.Rpo
- d = postorder(g.Start, rpo2r, 0)
- nr = int32(g.Num)
+ rpo2r := g.Rpo
+ d := postorder(g.Start, rpo2r, 0)
+ nr := int32(g.Num)
if d > nr {
Fatal("too many reg nodes %d %d", d, nr)
}
nr = d
- for i = 0; i < nr/2; i++ {
+ var r1 *Flow
+ for i := int32(0); i < nr/2; i++ {
r1 = rpo2r[i]
rpo2r[i] = rpo2r[nr-1-i]
rpo2r[nr-1-i] = r1
}
- for i = 0; i < nr; i++ {
+ for i := int32(0); i < nr; i++ {
rpo2r[i].Rpo = i
}
idom[0] = 0
- for i = 0; i < nr; i++ {
+ var me int32
+ for i := int32(0); i < nr; i++ {
r1 = rpo2r[i]
me = r1.Rpo
d = -1
@@ -617,7 +588,7 @@
idom[i] = d
}
- for i = 0; i < nr; i++ {
+ for i := int32(0); i < nr; i++ {
r1 = rpo2r[i]
r1.Loop++
if r1.P2 != nil && loophead(idom, r1) {
@@ -625,15 +596,13 @@
}
}
- for r1 = g.Start; r1 != nil; r1 = r1.Link {
+ for r1 := g.Start; r1 != nil; r1 = r1.Link {
r1.Active = 0
}
}
func Uniqp(r *Flow) *Flow {
- var r1 *Flow
-
- r1 = r.P1
+ r1 := r.P1
if r1 == nil {
r1 = r.P2
if r1 == nil || r1.P2link != nil {
@@ -646,9 +615,7 @@
}
func Uniqs(r *Flow) *Flow {
- var r1 *Flow
-
- r1 = r.S1
+ r1 := r.S1
if r1 == nil {
r1 = r.S2
if r1 == nil {
@@ -691,11 +658,8 @@
}
func (x startcmp) Less(i, j int) bool {
- var a *TempVar
- var b *TempVar
-
- a = x[i]
- b = x[j]
+ a := x[i]
+ b := x[j]
if a.start < b.start {
return true
@@ -723,48 +687,28 @@
}
func mergetemp(firstp *obj.Prog) {
- var i int
- var j int
- var nvar int
- var ninuse int
- var nfree int
- var nkill int
- var var_ []TempVar
- var v *TempVar
- var v1 *TempVar
- var bystart []*TempVar
- var inuse []*TempVar
- var f *Flow
- var l *NodeList
- var lp **NodeList
- var n *Node
- var p *obj.Prog
- var p1 *obj.Prog
- var t *Type
- var info ProgInfo
- var info1 ProgInfo
- var gen int32
- var g *Graph
const (
debugmerge = 1
)
- g = Flowstart(firstp, nil)
+ g := Flowstart(firstp, nil)
if g == nil {
return
}
// Build list of all mergeable variables.
- nvar = 0
- for l = Curfn.Dcl; l != nil; l = l.Next {
+ nvar := 0
+ for l := Curfn.Dcl; l != nil; l = l.Next {
if canmerge(l.N) {
nvar++
}
}
- var_ = make([]TempVar, nvar)
+ var_ := make([]TempVar, nvar)
nvar = 0
- for l = Curfn.Dcl; l != nil; l = l.Next {
+ var n *Node
+ var v *TempVar
+ for l := Curfn.Dcl; l != nil; l = l.Next {
n = l.N
if canmerge(n) {
v = &var_[nvar]
@@ -778,7 +722,9 @@
// We assume that the earliest reference to a temporary is its definition.
// This is not true of variables in general but our temporaries are all
// single-use (that's why we have so many!).
- for f = g.Start; f != nil; f = f.Link {
+ var p *obj.Prog
+ var info ProgInfo
+ for f := g.Start; f != nil; f = f.Link {
p = f.Prog
Thearch.Proginfo(&info, p)
@@ -812,10 +758,13 @@
Dumpit("before", g.Start, 0)
}
- nkill = 0
+ nkill := 0
// Special case.
- for i = 0; i < len(var_); i++ {
+ var p1 *obj.Prog
+ var info1 ProgInfo
+ var f *Flow
+ for i := 0; i < len(var_); i++ {
v = &var_[i]
if v.addr != 0 {
continue
@@ -868,9 +817,9 @@
// Traverse live range of each variable to set start, end.
// Each flood uses a new value of gen so that we don't have
// to clear all the r->active words after each variable.
- gen = 0
+ gen := int32(0)
- for i = 0; i < len(var_); i++ {
+ for i := 0; i < len(var_); i++ {
v = &var_[i]
gen++
for f = v.use; f != nil; f = f.Data.(*Flow) {
@@ -885,9 +834,9 @@
}
// Sort variables by start.
- bystart = make([]*TempVar, len(var_))
+ bystart := make([]*TempVar, len(var_))
- for i = 0; i < len(var_); i++ {
+ for i := 0; i < len(var_); i++ {
bystart[i] = &var_[i]
}
sort.Sort(startcmp(bystart[:len(var_)]))
@@ -898,11 +847,14 @@
// In theory we should use a sorted tree so that insertions are
// guaranteed O(log n) and then the loop is guaranteed O(n log n).
// In practice, it doesn't really matter.
- inuse = make([]*TempVar, len(var_))
+ inuse := make([]*TempVar, len(var_))
- ninuse = 0
- nfree = len(var_)
- for i = 0; i < len(var_); i++ {
+ ninuse := 0
+ nfree := len(var_)
+ var t *Type
+ var v1 *TempVar
+ var j int
+ for i := 0; i < len(var_); i++ {
v = bystart[i]
if debugmerge > 0 && Debug['v'] != 0 {
fmt.Printf("consider %v: removed=%d\n", Nconv(v.node, obj.FmtSharp), v.removed)
@@ -965,7 +917,8 @@
if debugmerge > 0 && Debug['v'] != 0 {
fmt.Printf("%v [%d - %d]\n", Sconv(Curfn.Nname.Sym, 0), len(var_), nkill)
- for i = 0; i < len(var_); i++ {
+ var v *TempVar
+ for i := 0; i < len(var_); i++ {
v = &var_[i]
fmt.Printf("var %v %v %d-%d", Nconv(v.node, obj.FmtSharp), Tconv(v.node.Type, 0), v.start, v.end)
if v.addr != 0 {
@@ -989,7 +942,7 @@
}
// Update node references to use merged temporaries.
- for f = g.Start; f != nil; f = f.Link {
+ for f := g.Start; f != nil; f = f.Link {
p = f.Prog
n, _ = p.From.Node.(*Node)
if n != nil {
@@ -1008,7 +961,8 @@
}
// Delete merged nodes from declaration list.
- for lp = &Curfn.Dcl; ; {
+ var l *NodeList
+ for lp := &Curfn.Dcl; ; {
l = *lp
if l == nil {
break
@@ -1026,7 +980,7 @@
}
// Clear aux structures.
- for i = 0; i < len(var_); i++ {
+ for i := 0; i < len(var_); i++ {
var_[i].node.Opt = nil
}
@@ -1036,8 +990,6 @@
func mergewalk(v *TempVar, f0 *Flow, gen uint32) {
var p *obj.Prog
var f1 *Flow
- var f *Flow
- var f2 *Flow
for f1 = f0; f1 != nil; f1 = f1.P1 {
if uint32(f1.Active) == gen {
@@ -1054,7 +1006,8 @@
}
}
- for f = f0; f != f1; f = f.P1 {
+ var f2 *Flow
+ for f := f0; f != f1; f = f.P1 {
for f2 = f.P2; f2 != nil; f2 = f2.P2link {
mergewalk(v, f2, gen)
}
@@ -1064,7 +1017,6 @@
func varkillwalk(v *TempVar, f0 *Flow, gen uint32) {
var p *obj.Prog
var f1 *Flow
- var f *Flow
for f1 = f0; f1 != nil; f1 = f1.S1 {
if uint32(f1.Active) == gen {
@@ -1083,7 +1035,7 @@
}
}
- for f = f0; f != f1; f = f.S1 {
+ for f := f0; f != f1; f = f.S1 {
varkillwalk(v, f.S2, gen)
}
}
@@ -1107,13 +1059,7 @@
var killed int // f->data is either nil or &killed
func nilopt(firstp *obj.Prog) {
- var f *Flow
- var p *obj.Prog
- var g *Graph
- var ncheck int
- var nkill int
-
- g = Flowstart(firstp, nil)
+ g := Flowstart(firstp, nil)
if g == nil {
return
}
@@ -1122,9 +1068,10 @@
Dumpit("nilopt", g.Start, 0)
}
- ncheck = 0
- nkill = 0
- for f = g.Start; f != nil; f = f.Link {
+ ncheck := 0
+ nkill := 0
+ var p *obj.Prog
+ for f := g.Start; f != nil; f = f.Link {
p = f.Prog
if p.As != obj.ACHECKNIL || !Thearch.Regtyp(&p.From) {
continue
@@ -1155,7 +1102,7 @@
}
}
- for f = g.Start; f != nil; f = f.Link {
+ for f := g.Start; f != nil; f = f.Link {
if f.Data != nil {
nkill++
Thearch.Excise(f)
@@ -1172,9 +1119,8 @@
func nilwalkback(fcheck *Flow) {
var p *obj.Prog
var info ProgInfo
- var f *Flow
- for f = fcheck; f != nil; f = Uniqp(f) {
+ for f := fcheck; f != nil; f = Uniqp(f) {
p = f.Prog
Thearch.Proginfo(&info, p)
if (info.Flags&RightWrite != 0) && Thearch.Sameaddr(&p.To, &fcheck.Prog.From) {
@@ -1231,8 +1177,6 @@
nilwalkback(fcheck, f2, gen);
*/
func nilwalkfwd(fcheck *Flow) {
- var f *Flow
- var last *Flow
var p *obj.Prog
var info ProgInfo
@@ -1243,9 +1187,9 @@
// avoid problems like:
// _ = *x // should panic
// for {} // no writes but infinite loop may be considered visible
- last = nil
+ last := (*Flow)(nil)
- for f = Uniqs(fcheck); f != nil; f = Uniqs(f) {
+ for f := Uniqs(fcheck); f != nil; f = Uniqs(f) {
p = f.Prog
Thearch.Proginfo(&info, p)
