// errorcheck -0 -l -d=wb
// Copyright 2015 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.
// Test where write barriers are and are not emitted.
package p
import "unsafe"
func f(x **byte, y *byte) {
*x = y // no barrier (dead store)
z := y // no barrier
*x = z // ERROR "write barrier"
}
func f1(x *[]byte, y []byte) {
*x = y // no barrier (dead store)
z := y // no barrier
*x = z // ERROR "write barrier"
}
func f1a(x *[]byte, y *[]byte) {
*x = *y // ERROR "write barrier"
z := *y // no barrier
*x = z // ERROR "write barrier"
}
func f2(x *interface{}, y interface{}) {
*x = y // no barrier (dead store)
z := y // no barrier
*x = z // ERROR "write barrier"
}
func f2a(x *interface{}, y *interface{}) {
*x = *y // no barrier (dead store)
z := y // no barrier
*x = z // ERROR "write barrier"
}
func f3(x *string, y string) {
*x = y // no barrier (dead store)
z := y // no barrier
*x = z // ERROR "write barrier"
}
func f3a(x *string, y *string) {
*x = *y // ERROR "write barrier"
z := *y // no barrier
*x = z // ERROR "write barrier"
}
func f4(x *[2]string, y [2]string) {
*x = y // ERROR "write barrier"
z := y // no barrier
*x = z // ERROR "write barrier"
}
func f4a(x *[2]string, y *[2]string) {
*x = *y // ERROR "write barrier"
z := *y // no barrier
*x = z // ERROR "write barrier"
}
type T struct {
X *int
Y int
M map[int]int
}
func f5(t, u *T) {
t.X = &u.Y // ERROR "write barrier"
}
func f6(t *T) {
t.M = map[int]int{1: 2} // ERROR "write barrier"
}
func f7(x, y *int) []*int {
var z [3]*int
i := 0
z[i] = x // ERROR "write barrier"
i++
z[i] = y // ERROR "write barrier"
i++
return z[:i]
}
func f9(x *interface{}, v *byte) {
*x = v // ERROR "write barrier"
}
func f10(x *byte, f func(interface{})) {
f(x)
}
func f11(x *unsafe.Pointer, y unsafe.Pointer) {
*x = unsafe.Pointer(uintptr(y) + 1) // ERROR "write barrier"
}
func f12(x []*int, y *int) []*int {
// write barrier for storing y in x's underlying array
x = append(x, y) // ERROR "write barrier"
return x
}
func f12a(x []int, y int) []int {
// y not a pointer, so no write barriers in this function
x = append(x, y)
return x
}
func f13(x []int, y *[]int) {
*y = append(x, 1) // ERROR "write barrier"
}
func f14(y *[]int) {
*y = append(*y, 1) // ERROR "write barrier"
}
type T1 struct {
X *int
}
func f15(x []T1, y T1) []T1 {
return append(x, y) // ERROR "write barrier"
}
type T8 struct {
X [8]*int
}
func f16(x []T8, y T8) []T8 {
return append(x, y) // ERROR "write barrier"
}
func t1(i interface{}) **int {
// From issue 14306, make sure we have write barriers in a type switch
// where the assigned variable escapes.
switch x := i.(type) {
case *int: // ERROR "write barrier"
return &x
}
switch y := i.(type) {
case **int: // no write barrier here
return y
}
return nil
}
type T17 struct {
f func(*T17)
}
func f17(x *T17) {
// Originally from golang.org/issue/13901, but the hybrid
// barrier requires both to have barriers.
x.f = f17 // ERROR "write barrier"
x.f = func(y *T17) { *y = *x } // ERROR "write barrier"
}
type T18 struct {
a []int
s string
}
func f18(p *T18, x *[]int) {
p.a = p.a[:5] // no barrier
*x = (*x)[0:5] // no barrier
p.a = p.a[3:5] // ERROR "write barrier"
p.a = p.a[1:2:3] // ERROR "write barrier"
p.s = p.s[8:9] // ERROR "write barrier"
*x = (*x)[3:5] // ERROR "write barrier"
}
func f19(x, y *int, i int) int {
// Constructing a temporary slice on the stack should not
// require any write barriers. See issue 14263.
a := []*int{x, y} // no barrier
return *a[i]
}
func f20(x, y *int, i int) []*int {
// ... but if that temporary slice escapes, then the
// write barriers are necessary.
a := []*int{x, y} // ERROR "write barrier"
return a
}
var x21 *int
var y21 struct {
x *int
}
var z21 int
// f21x: Global -> heap pointer updates must have write barriers.
func f21a(x *int) {
x21 = x // ERROR "write barrier"
y21.x = x // ERROR "write barrier"
}
func f21b(x *int) {
x21 = &z21 // ERROR "write barrier"
y21.x = &z21 // ERROR "write barrier"
}
func f21c(x *int) {
y21 = struct{ x *int }{x} // ERROR "write barrier"
}
func f22(x *int) (y *int) {
// pointer write on stack should have no write barrier.
// this is a case that the frontend failed to eliminate.
p := &y
*p = x // no barrier
return
}
type T23 struct {
p *int
a int
}
var t23 T23
var i23 int
// f23x: zeroing global needs write barrier for the hybrid barrier.
func f23a() {
t23 = T23{} // ERROR "write barrier"
}
func f23b() {
// also test partial assignments
t23 = T23{a: 1} // ERROR "write barrier"
}
func f23c() {
t23 = T23{} // no barrier (dead store)
// also test partial assignments
t23 = T23{p: &i23} // ERROR "write barrier"
}
var g int
func f24() **int {
p := new(*int)
*p = &g // no write barrier here
return p
}
func f25() []string {
return []string{"abc", "def", "ghi"} // no write barrier here
}
type T26 struct {
a, b, c int
d, e, f *int
}
var g26 int
func f26(p *int) *T26 { // see issue 29573
return &T26{
a: 5,
b: 6,
c: 7,
d: &g26, // no write barrier: global ptr
e: nil, // no write barrier: nil ptr
f: p, // ERROR "write barrier"
}
}
func f27(p *int) []interface{} {
return []interface{}{
nil, // no write barrier: zeroed memory, nil ptr
(*T26)(nil), // no write barrier: zeroed memory, type ptr & nil ptr
&g26, // no write barrier: zeroed memory, type ptr & global ptr
7, // no write barrier: zeroed memory, type ptr & global ptr
p, // ERROR "write barrier"
}
}
var g28 [256]uint64
func f28() []interface{} {
return []interface{}{
false, // no write barrier
true, // no write barrier
0, // no write barrier
1, // no write barrier
uint8(127), // no write barrier
int8(-4), // no write barrier
&g28[5], // no write barrier
}
}
Directory Contents
Dirs: 24 × Files: 338
!"#$%&'(()*+,-./00123456789 t\
wIDATx ]ys 47Y ƒ - " Rv < f{Ɛ $k l L > L ~h^ 1 [ r G t& h
l F z3O Y ! p A(_g̷ E8 )S 8 c Kb"z ~ 5 J xAL WU < *
5 m;W a pB h ~P J
2 3 6 ҙ .Ƹ P i 4g
F R L P ΪK/D M v (a3
k J
Œ4N5* SH ` SdJ z O J Xՠ V> u ߱ BE&L b2 ?2` tX+ c CB A$ i b C ĀMB E : / # Dx &l =q Ty 0 \p I ( L Ǎ { e
4k ;`u^ｦ eP!( d { )T A 8 O;Ě n >;s6 ! :Nx `[S D HU ~ qJ F}
a g*D 49 / pn k h (t 8NxƐF _!r չ7
ZR R q/5") Ӎ NY 0 x sZ! o
fu , K"$ ? pg 㕣= 1» {h " fh7
y } +7 $ y
" X ą - G P u 4 m >J 5 L =V ' ^@I p ?MS xЌ XV P ! h "C NS9B8̢ ]!K e zA , ӏkbY !< XQ ٿyS| *" f { w 4@[S <
# 0 ! js [m =,~ o
"ݎ DHf Wo $ g ! Vԅ t mB /y Wf V4 c+@x? B ~u " xUN e 0 BĂ)
~J pz!
7 y6]l Ԥ@ P a< O /DHC `≻ N m"$ 0ObB }{ x AO FCG D R ^ "B { WDH UR l@ T
# +"d T ; 0 i D}. 7 ` ' ] w rE &S i ƕiTD EL P _ u h $ Ա FG wVD G L R Zf ' .!] J /ZR oGЍ s Mr Ĥ ʬ 3 Q [3 cL ` ^ p +
( F;# B 5 ' 2Y f [ ϶R0e } E 7
6M aۮ H <& n % L] E}Up x紉, Uw' Q Ǯշo k ވۙ 0N94 VX5 xEDE l D #֤ } C o )W : ^ s 9 bRf iX5u ཱི 4 :[ T 1. | [E 2ؽ Iy\ : o x K G 5
ylP ' uK E
ftb/i[3 .g _ [3M n
G, #NwQ5~
ؚ) | n =Ц"x qg gB ` 듘 ~ x w ?
?
R~ _ u. &V Q K˻ H C ( TN˄+ `C dA n B D 3"Z G ê ^k H_ /- ~ " R_ .8 Z_ 6@ o xg uP ? 3լ @7AM! E7^
- =V L x g-D0 CtmW 7 O G _ WD0 g C w1 r
d w : a | \ *" f nֳ ^ H# f L ` Z ۽hV }S F r0Ù Bć5r] @! NL iQ]{s^=4 d WD " " M;
t" 8 5 e dL| "-*st" ) SWD ?R[S e ooF 20.D ? bo =) A i o d ģ ZҰaO
@E =) i D a &ܟa CϞ y6 ,<%{^x%{f8? `iw^ ?/
M
* IEND B`