1// run
2
3// Copyright 2009 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
7package main
8
9// Test for correct heap-moving of escaped variables.
10// It is hard to check for the allocations, but it is easy
11// to check that if you call the function twice at the
12// same stack level, the pointers returned should be
13// different.
14
15var bad = false
16
17var allptr = make([]*int, 0, 100)
18
19func noalias(p, q *int, s string) {
20	n := len(allptr)
21	*p = -(n + 1)
22	*q = -(n + 2)
23	allptr = allptr[0 : n+2]
24	allptr[n] = p
25	allptr[n+1] = q
26	n += 2
27	for i := 0; i < n; i++ {
28		if allptr[i] != nil && *allptr[i] != -(i+1) {
29			println("aliased pointers", -(i + 1), *allptr[i], "after", s)
30			allptr[i] = nil
31			bad = true
32		}
33	}
34}
35
36func val(p, q *int, v int, s string) {
37	if *p != v {
38		println("wrong value want", v, "got", *p, "after", s)
39		bad = true
40	}
41	if *q != v+1 {
42		println("wrong value want", v+1, "got", *q, "after", s)
43		bad = true
44	}
45}
46
47func chk(p, q *int, v int, s string) {
48	val(p, q, v, s)
49	noalias(p, q, s)
50}
51
52func chkalias(p, q *int, v int, s string) {
53	if p != q {
54		println("want aliased pointers but got different after", s)
55		bad = true
56	}
57	if *q != v+1 {
58		println("wrong value want", v+1, "got", *q, "after", s)
59		bad = true
60	}
61}
62
63func i_escapes(x int) *int {
64	var i int
65	i = x
66	return &i
67}
68
69func j_escapes(x int) *int {
70	var j int = x
71	j = x
72	return &j
73}
74
75func k_escapes(x int) *int {
76	k := x
77	return &k
78}
79
80func in_escapes(x int) *int {
81	return &x
82}
83
84func send(c chan int, x int) {
85	c <- x
86}
87
88func select_escapes(x int) *int {
89	c := make(chan int)
90	go send(c, x)
91	select {
92	case req := <-c:
93		return &req
94	}
95	return nil
96}
97
98func select_escapes1(x int, y int) (*int, *int) {
99	c := make(chan int)
100	var a [2]int
101	var p [2]*int
102	a[0] = x
103	a[1] = y
104	for i := 0; i < 2; i++ {
105		go send(c, a[i])
106		select {
107		case req := <-c:
108			p[i] = &req
109		}
110	}
111	return p[0], p[1]
112}
113
114func range_escapes(x int) *int {
115	var a [1]int
116	a[0] = x
117	for _, v := range a {
118		return &v
119	}
120	return nil
121}
122
123// *is* aliased
124func range_escapes2(x, y int) (*int, *int) {
125	var a [2]int
126	var p [2]*int
127	a[0] = x
128	a[1] = y
129	var k, v int
130	for k, v = range a {
131		p[k] = &v
132	}
133	return p[0], p[1]
134}
135
136// *is* aliased
137func for_escapes2(x int, y int) (*int, *int) {
138	var p [2]*int
139	n := 0
140	i := x
141	for ; n < 2; i = y {
142		p[n] = &i
143		n++
144	}
145	return p[0], p[1]
146}
147
148func for_escapes3(x int, y int) (*int, *int) {
149	var f [2]func() *int
150	n := 0
151	for i := x; n < 2; i = y {
152		p := new(int)
153		*p = i
154		f[n] = func() *int { return p }
155		n++
156	}
157	return f[0](), f[1]()
158}
159
160func out_escapes(i int) (x int, p *int) {
161	x = i
162	p = &x // ERROR "address of out parameter"
163	return
164}
165
166func out_escapes_2(i int) (x int, p *int) {
167	x = i
168	return x, &x // ERROR "address of out parameter"
169}
170
171func defer1(i int) (x int) {
172	c := make(chan int)
173	go func() { x = i; c <- 1 }()
174	<-c
175	return
176}
177
178func main() {
179	p, q := i_escapes(1), i_escapes(2)
180	chk(p, q, 1, "i_escapes")
181
182	p, q = j_escapes(3), j_escapes(4)
183	chk(p, q, 3, "j_escapes")
184
185	p, q = k_escapes(5), k_escapes(6)
186	chk(p, q, 5, "k_escapes")
187
188	p, q = in_escapes(7), in_escapes(8)
189	chk(p, q, 7, "in_escapes")
190
191	p, q = select_escapes(9), select_escapes(10)
192	chk(p, q, 9, "select_escapes")
193
194	p, q = select_escapes1(11, 12)
195	chk(p, q, 11, "select_escapes1")
196
197	p, q = range_escapes(13), range_escapes(14)
198	chk(p, q, 13, "range_escapes")
199
200	p, q = range_escapes2(101, 102)
201	chkalias(p, q, 101, "range_escapes2")
202
203	p, q = for_escapes2(103, 104)
204	chkalias(p, q, 103, "for_escapes2")
205
206	p, q = for_escapes3(105, 106)
207	chk(p, q, 105, "for_escapes3")
208
209	_, p = out_escapes(15)
210	_, q = out_escapes(16)
211	chk(p, q, 15, "out_escapes")
212
213	_, p = out_escapes_2(17)
214	_, q = out_escapes_2(18)
215	chk(p, q, 17, "out_escapes_2")
216
217	x := defer1(20)
218	if x != 20 {
219		println("defer failed", x)
220		bad = true
221	}
222
223	if bad {
224		panic("BUG: no escape")
225	}
226}
227