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cmd/compile: clean up SSA-building code

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Now that the write barrier insertion is moved to SSA, the SSA
building code can be simplified.

Updates #17583.

Change-Id: I5cacc034b11aa90b0abe6f8dd97e4e3994e2bc25
Reviewed-on: https://go-review.googlesource.com/36840
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Cherry Zhang 2017-02-10 10:15:10 -05:00
parent 9ebf3d5100
commit 1b85300602
5 changed files with 62 additions and 189 deletions
Download patch file Download diff file Expand all files Collapse all files

12
src/cmd/compile/internal/ssa/writebarrier.go
View file

@ -19,7 +19,7 @@ func needwb(v *Value) bool {
if !t.HasPointer() {
return false
}
if IsStackAddr(v.Args[0]) {
if isStackAddr(v.Args[0]) {
return false // write on stack doesn't need write barrier
}
return true
@ -207,6 +207,12 @@ func writebarrier(f *Func) {
memElse = bElse.NewValue3I(pos, op, TypeMem, siz, ptr, val, memElse)
}
if f.NoWB {
f.Config.fe.Error(pos, "write barrier prohibited")
}
if !f.WBPos.IsKnown() {
f.WBPos = pos
}
if f.Config.fe.Debug_wb() {
f.Config.Warnl(pos, "write barrier")
}
@ -309,8 +315,8 @@ func round(o int64, r int64) int64 {
return (o + r - 1) &^ (r - 1)
}
// IsStackAddr returns whether v is known to be an address of a stack slot
func IsStackAddr(v *Value) bool {
// isStackAddr returns whether v is known to be an address of a stack slot
func isStackAddr(v *Value) bool {
for v.Op == OpOffPtr || v.Op == OpAddPtr || v.Op == OpPtrIndex || v.Op == OpCopy {
v = v.Args[0]
}