mirror of
https://github.com/golang/go.git
synced 2025-05-05 15:43:04 +00:00
3e54ca9a46
Currently we generate write barriers when the right side of an assignment is a global function. This doesn't fall into the existing case of storing an address of a global because we haven't lowered the function to a pointer yet. This write barrier is unnecessary, so eliminate it. Fixes #13901. Change-Id: Ibc10e00a8803db0fd75224b66ab94c3737842a79 Reviewed-on: https://go-review.googlesource.com/20772 Run-TryBot: Austin Clements <austin@google.com> Reviewed-by: Keith Randall <khr@golang.org>
171 lines
3.0 KiB
Go
171 lines
3.0 KiB
Go
// 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 // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f1(x *[]byte, y []byte) {
|
|
*x = y // ERROR "write barrier"
|
|
|
|
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 // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f2a(x *interface{}, y *interface{}) {
|
|
*x = *y // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f3(x *string, y string) {
|
|
*x = y // ERROR "write barrier"
|
|
|
|
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) { // ERROR "write barrier"
|
|
case *int:
|
|
return &x
|
|
}
|
|
switch y := i.(type) { // no write barrier here
|
|
case **int:
|
|
return y
|
|
}
|
|
return nil
|
|
}
|
|
|
|
type T17 struct {
|
|
f func(*T17)
|
|
}
|
|
|
|
func f17(x *T17) {
|
|
// See golang.org/issue/13901
|
|
x.f = f17 // no barrier
|
|
x.f = func(y *T17) { *y = *x } // ERROR "write barrier"
|
|
}
|