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https://github.com/golang/go
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cca23a7373
This is a revert of https://go-review.googlesource.com/c/go/+/316890, which has positive effects on debugging + DWARF variable locations for register parameters when the reg abi is in effect, but also turns out to interact badly with the register allocator. Fixes #46304. Change-Id: I624bd980493411a9cde45d44fcd3c46cad796909 Reviewed-on: https://go-review.googlesource.com/c/go/+/321830 Trust: Than McIntosh <thanm@google.com> Run-TryBot: Than McIntosh <thanm@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Go Bot <gobot@golang.org>
77 lines
1.1 KiB
Go
77 lines
1.1 KiB
Go
// run
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// Copyright 2021 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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// This testcase caused a crash when the register ABI was in effect,
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// on amd64 (problem with register allocation).
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package main
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type Op struct {
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tag string
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_x []string
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_q [20]uint64
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plist []P
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}
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type P struct {
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tag string
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_x [10]uint64
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b bool
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}
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type M int
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//go:noinline
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func (w *M) walkP(p *P) *P {
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np := &P{}
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*np = *p
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np.tag += "new"
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return np
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}
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func (w *M) walkOp(op *Op) *Op {
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if op == nil {
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return nil
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}
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orig := op
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cloned := false
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clone := func() {
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if !cloned {
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cloned = true
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op = &Op{}
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*op = *orig
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}
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}
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pCloned := false
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for i := range op.plist {
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if s := w.walkP(&op.plist[i]); s != &op.plist[i] {
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if !pCloned {
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pCloned = true
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clone()
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op.plist = make([]P, len(orig.plist))
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copy(op.plist, orig.plist)
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}
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op.plist[i] = *s
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}
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}
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return op
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}
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func main() {
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var ww M
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w := &ww
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p1 := P{tag: "a"}
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p1._x[1] = 9
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o := Op{tag: "old", plist: []P{p1}}
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no := w.walkOp(&o)
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if no.plist[0].tag != "anew" {
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panic("bad")
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}
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}
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