summaryrefslogtreecommitdiffstats
path: root/test/fixedbugs/issue32477.go
blob: 8b3c17528985de89db7f3009d60261575580fbce (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
// 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
}