1// run
2
3// Copyright 2016 The Go Authors.  All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7// issue 16515: spilled Duff-adjusted address may be invalid
8
9package main
10
11import "runtime"
12
13type T [62]int // DUFFZERO with non-zero adjustment on AMD64
14
15var sink interface{}
16
17//go:noinline
18func zero(x *T) {
19	// Two DUFFZEROs on the same address with a function call in between.
20	// Duff-adjusted address will be spilled and loaded
21
22	*x = T{} // DUFFZERO
23	runtime.GC()
24	(*x)[0] = 1
25	g()      // call a function with large frame, trigger a stack move
26	*x = T{} // DUFFZERO again
27}
28
29//go:noinline
30// a function with large frame
31func g() {
32	var x [1000]int
33	_ = x
34}
35
36func main() {
37	var s struct { a T; b [8192-62]int } // allocate 64K, hopefully it's in a new span and a few bytes before it is garbage
38	sink = &s // force heap allocation
39	s.a[0] = 2
40	zero(&s.a)
41	if s.a[0] != 0 {
42		println("s.a[0] =", s.a[0])
43		panic("zeroing failed")
44	}
45
46	var a T // on stack
47	a[0] = 2
48	zero(&a)
49	if a[0] != 0 {
50		println("a[0] =", a[0])
51		panic("zeroing failed")
52	}
53}
54