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// run
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Make sure we use the deferreturn live map instead of
// the entry live map when handling a segv in a function
// that defers.
package main
import "runtime"
var finalized bool
var err string
type HeapObj [8]int64
const filler int64 = 0x123456789abcdef0
func (h *HeapObj) init() {
for i := 0; i < len(*h); i++ {
h[i] = filler
}
}
func (h *HeapObj) check() {
for i := 0; i < len(*h); i++ {
if h[i] != filler {
err = "filler overwritten"
}
}
}
func gc(shouldFinalize bool) {
runtime.GC()
runtime.GC()
runtime.GC()
if shouldFinalize != finalized {
err = "heap object finalized at the wrong time"
}
}
func main() {
h := new(HeapObj)
h.init()
runtime.SetFinalizer(h, func(h *HeapObj) {
finalized = true
})
gc(false)
g(h)
if err != "" {
panic(err)
}
}
func g(h *HeapObj) {
gc(false)
h.check()
// h is now unused
defer func() {
// h should not be live here. Previously we used to
// use the function entry point as the place to get
// the live map when handling a segv.
gc(true)
recover()
}()
*(*int)(nil) = 0 // trigger a segv
return
}
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