Source file
test/escape.go
Documentation: test
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7 package main
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15 var bad = false
16
17 var allptr = make([]*int, 0, 100)
18
19 func 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
36 func 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
47 func chk(p, q *int, v int, s string) {
48 val(p, q, v, s)
49 noalias(p, q, s)
50 }
51
52 func 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
63 func i_escapes(x int) *int {
64 var i int
65 i = x
66 return &i
67 }
68
69 func j_escapes(x int) *int {
70 var j int = x
71 j = x
72 return &j
73 }
74
75 func k_escapes(x int) *int {
76 k := x
77 return &k
78 }
79
80 func in_escapes(x int) *int {
81 return &x
82 }
83
84 func send(c chan int, x int) {
85 c <- x
86 }
87
88 func 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
98 func 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
114 func 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
124 func 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 for k, v := range a {
130 p[k] = &v
131 }
132 return p[0], p[1]
133 }
134
135
136 func for_escapes2(x int, y int) (*int, *int) {
137 var p [2]*int
138 n := 0
139 for i := x; n < 2; i = y {
140 p[n] = &i
141 n++
142 }
143 return p[0], p[1]
144 }
145
146 func for_escapes3(x int, y int) (*int, *int) {
147 var f [2]func() *int
148 n := 0
149 for i := x; n < 2; i = y {
150 p := new(int)
151 *p = i
152 f[n] = func() *int { return p }
153 n++
154 }
155 return f[0](), f[1]()
156 }
157
158 func out_escapes(i int) (x int, p *int) {
159 x = i
160 p = &x
161 return
162 }
163
164 func out_escapes_2(i int) (x int, p *int) {
165 x = i
166 return x, &x
167 }
168
169 func defer1(i int) (x int) {
170 c := make(chan int)
171 go func() { x = i; c <- 1 }()
172 <-c
173 return
174 }
175
176 func main() {
177 p, q := i_escapes(1), i_escapes(2)
178 chk(p, q, 1, "i_escapes")
179
180 p, q = j_escapes(3), j_escapes(4)
181 chk(p, q, 3, "j_escapes")
182
183 p, q = k_escapes(5), k_escapes(6)
184 chk(p, q, 5, "k_escapes")
185
186 p, q = in_escapes(7), in_escapes(8)
187 chk(p, q, 7, "in_escapes")
188
189 p, q = select_escapes(9), select_escapes(10)
190 chk(p, q, 9, "select_escapes")
191
192 p, q = select_escapes1(11, 12)
193 chk(p, q, 11, "select_escapes1")
194
195 p, q = range_escapes(13), range_escapes(14)
196 chk(p, q, 13, "range_escapes")
197
198 p, q = range_escapes2(101, 102)
199 chkalias(p, q, 101, "range_escapes2")
200
201 p, q = for_escapes2(103, 104)
202 chkalias(p, q, 103, "for_escapes2")
203
204 p, q = for_escapes3(105, 106)
205 chk(p, q, 105, "for_escapes3")
206
207 _, p = out_escapes(15)
208 _, q = out_escapes(16)
209 chk(p, q, 15, "out_escapes")
210
211 _, p = out_escapes_2(17)
212 _, q = out_escapes_2(18)
213 chk(p, q, 17, "out_escapes_2")
214
215 x := defer1(20)
216 if x != 20 {
217 println("defer failed", x)
218 bad = true
219 }
220
221 if bad {
222 panic("BUG: no escape")
223 }
224 }
225
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