1 // errorcheck -0 -l -d=wb
3 // Copyright 2015 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.
7 // Test where write barriers are and are not emitted.
13 func f(x **byte, y *byte) {
14 *x = y // ERROR "write barrier"
17 *x = z // ERROR "write barrier"
20 func f1(x *[]byte, y []byte) {
21 *x = y // ERROR "write barrier"
24 *x = z // ERROR "write barrier"
27 func f1a(x *[]byte, y *[]byte) {
28 *x = *y // ERROR "write barrier"
31 *x = z // ERROR "write barrier"
34 func f2(x *interface{}, y interface{}) {
35 *x = y // ERROR "write barrier"
38 *x = z // ERROR "write barrier"
41 func f2a(x *interface{}, y *interface{}) {
42 *x = *y // ERROR "write barrier"
45 *x = z // ERROR "write barrier"
48 func f3(x *string, y string) {
49 *x = y // ERROR "write barrier"
52 *x = z // ERROR "write barrier"
55 func f3a(x *string, y *string) {
56 *x = *y // ERROR "write barrier"
59 *x = z // ERROR "write barrier"
62 func f4(x *[2]string, y [2]string) {
63 *x = y // ERROR "write barrier"
66 *x = z // ERROR "write barrier"
69 func f4a(x *[2]string, y *[2]string) {
70 *x = *y // ERROR "write barrier"
73 *x = z // ERROR "write barrier"
83 t.X = &u.Y // ERROR "write barrier"
87 t.M = map[int]int{1: 2} // ERROR "write barrier"
90 func f7(x, y *int) []*int {
93 z[i] = x // ERROR "write barrier"
95 z[i] = y // ERROR "write barrier"
100 func f9(x *interface{}, v *byte) {
101 *x = v // ERROR "write barrier"
104 func f10(x *byte, f func(interface{})) {
108 func f11(x *unsafe.Pointer, y unsafe.Pointer) {
109 *x = unsafe.Pointer(uintptr(y) + 1) // ERROR "write barrier"
112 func f12(x []*int, y *int) []*int {
113 // write barrier for storing y in x's underlying array
114 x = append(x, y) // ERROR "write barrier"
118 func f12a(x []int, y int) []int {
119 // y not a pointer, so no write barriers in this function
124 func f13(x []int, y *[]int) {
125 *y = append(x, 1) // ERROR "write barrier"
129 *y = append(*y, 1) // ERROR "write barrier"
136 func f15(x []T1, y T1) []T1 {
137 return append(x, y) // ERROR "write barrier"
144 func f16(x []T8, y T8) []T8 {
145 return append(x, y) // ERROR "write barrier"
148 func t1(i interface{}) **int {
149 // From issue 14306, make sure we have write barriers in a type switch
150 // where the assigned variable escapes.
151 switch x := i.(type) { // ERROR "write barrier"
155 switch y := i.(type) { // no write barrier here
167 // See golang.org/issue/13901
168 x.f = f17 // no barrier
169 x.f = func(y *T17) { *y = *x } // ERROR "write barrier"
177 func f18(p *T18, x *[]int) {
178 p.a = p.a[:5] // no barrier
179 *x = (*x)[0:5] // no barrier
180 p.a = p.a[3:5] // ERROR "write barrier"
181 p.a = p.a[1:2:3] // ERROR "write barrier"
182 p.s = p.s[8:9] // ERROR "write barrier"
183 *x = (*x)[3:5] // ERROR "write barrier"
186 func f19(x, y *int, i int) int {
187 // Constructing a temporary slice on the stack should not
188 // require any write barriers. See issue 14263.
189 a := []*int{x, y} // no barrier
193 func f20(x, y *int, i int) []*int {
194 // ... but if that temporary slice escapes, then the
195 // write barriers are necessary.
196 a := []*int{x, y} // ERROR "write barrier"
207 // Global -> heap pointer updates must have write barriers.
208 x21 = x // ERROR "write barrier"
209 y21.x = x // ERROR "write barrier"
210 x21 = &z21 // no barrier
211 y21.x = &z21 // no barrier
212 y21 = struct{ x *int }{x} // ERROR "write barrier"