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cmd/compile/internal/ppc64: fix the epilogue for non-leaf generated methods
This lets us re-enable duffzero. Fixes #12108 Change-Id: Iefd24d26eaa56067caa2c29ff99cd20a42d8714a Reviewed-on: https://go-review.googlesource.com/14937 Reviewed-by: Keith Randall <khr@golang.org>
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@ -71,10 +71,7 @@ func zerorange(p *obj.Prog, frame int64, lo int64, hi int64) *obj.Prog {
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for i := int64(0); i < cnt; i += int64(gc.Widthptr) {
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p = appendpp(p, ppc64.AMOVD, obj.TYPE_REG, ppc64.REGZERO, 0, obj.TYPE_MEM, ppc64.REGSP, 8+frame+lo+i)
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}
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// TODO(dfc): https://golang.org/issue/12108
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// If DUFFZERO is used inside a tail call (see genwrapper) it will
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// overwrite the link register.
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} else if false && cnt <= int64(128*gc.Widthptr) {
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} else if cnt <= int64(128*gc.Widthptr) {
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p = appendpp(p, ppc64.AADD, obj.TYPE_CONST, 0, 8+frame+lo-8, obj.TYPE_REG, ppc64.REGRT1, 0)
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p.Reg = ppc64.REGSP
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p = appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
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@ -443,10 +440,7 @@ func clearfat(nl *gc.Node) {
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// The loop leaves R3 on the last zeroed dword
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boff = 8
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// TODO(dfc): https://golang.org/issue/12108
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// If DUFFZERO is used inside a tail call (see genwrapper) it will
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// overwrite the link register.
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} else if false && q >= 4 {
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} else if q >= 4 {
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p := gins(ppc64.ASUB, nil, &dst)
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p.From.Type = obj.TYPE_CONST
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p.From.Offset = 8
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@ -473,18 +473,19 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
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break
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}
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if p.To.Sym != nil { // retjmp
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p.As = ABR
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p.To.Type = obj.TYPE_BRANCH
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break
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}
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retTarget := p.To.Sym
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if cursym.Text.Mark&LEAF != 0 {
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if autosize == 0 {
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p.As = ABR
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p.From = obj.Addr{}
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_LR
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if retTarget == nil {
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_LR
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} else {
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p.To.Type = obj.TYPE_BRANCH
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p.To.Sym = retTarget
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}
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p.Mark |= BRANCH
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break
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}
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@ -562,14 +563,18 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
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q1 = ctxt.NewProg()
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q1.As = ABR
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q1.Lineno = p.Lineno
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q1.To.Type = obj.TYPE_REG
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q1.To.Reg = REG_LR
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if retTarget == nil {
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q1.To.Type = obj.TYPE_REG
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q1.To.Reg = REG_LR
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} else {
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q1.To.Type = obj.TYPE_BRANCH
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q1.To.Sym = retTarget
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}
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q1.Mark |= BRANCH
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q1.Spadj = +autosize
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q1.Link = q.Link
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q.Link = q1
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case AADD:
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if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
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p.Spadj = int32(-p.From.Offset)
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37
test/fixedbugs/issue12108.go
Normal file
37
test/fixedbugs/issue12108.go
Normal file
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@ -0,0 +1,37 @@
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// run
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// A generated method with a return value large enough to be
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// initialized by duffzero is not a leaf method, which violated
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// assumptions made by cmd/internal/obj/ppc64.
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package main
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const N = 9 // values > 8 cause (Super).Method to use duffzero
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type Base struct {
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}
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func (b *Base) Method() (x [N]uintptr) {
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return
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}
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type Super struct {
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Base
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}
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type T interface {
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Method() [N]uintptr
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}
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func f(q T) {
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q.Method()
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}
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func main() {
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var s Super
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f(&s)
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}
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