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31d13f479a
The location of VARDEFs is incorrect for PPARAMOUT variables which are also used as temporary locations. We put in VARDEFs when setting the variable at return time, but when the location is also used as a temporary the lifetime values are wrong. Fix copyelim to update the names map properly. This is a real name bug fix which, as a result, allows me to write a reasonable test to trigger the PPARAMOUT bug. This is kind of a band-aid fix for #14591. A more pricipled fix (which allows values to be stored in the return variable earlier than the return point) will be harder. Fixes #14591 Change-Id: I7df8ae103a982d1f218ed704c080d7b83cdcfdd9 Reviewed-on: https://go-review.googlesource.com/20457 Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
39 lines
770 B
Go
39 lines
770 B
Go
// run
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// Copyright 2016 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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// Test to make sure we don't think values are dead
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// when they are assigned to a PPARAMOUT slot before
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// the last GC safepoint.
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package main
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import (
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"fmt"
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"runtime"
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)
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// When a T is deallocated, T[1] is certain to
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// get clobbered (the runtime writes 0xdeaddeaddeaddead there).
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type T [4]int
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func f() (r, s *T) {
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r = &T{0x30, 0x31, 0x32, 0x33}
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runtime.GC()
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s = &T{0x40, 0x41, 0x42, 0x43}
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runtime.GC()
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return
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}
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func main() {
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r, s := f()
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if r[1] != 0x31 {
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fmt.Printf("bad r[1], want 0x31 got %x\n", r[1])
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}
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if s[1] != 0x41 {
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fmt.Printf("bad s[1], want 0x41 got %x\n", s[1])
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}
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}
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