mirror of
https://github.com/golang/go
synced 2024-11-18 08:14:41 -07:00
53 lines
865 B
Go
53 lines
865 B
Go
|
// run
|
||
|
|
|
||
|
|
// Copyright 2019 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.
|
||
|
|
|
||
|
|
// Issue 30977: write barrier call clobbers volatile
|
||
|
|
// value when there are multiple uses of the value.
|
||
|
|
|
||
|
|
package main
|
||
|
|
|
||
|
|
import "runtime"
|
||
|
|
|
||
|
|
type T struct {
|
||
|
|
a, b, c, d, e string
|
||
|
|
}
|
||
|
|
|
||
|
|
//go:noinline
|
||
|
|
func g() T {
|
||
|
|
return T{"a", "b", "c", "d", "e"}
|
||
|
|
}
|
||
|
|
|
||
|
|
//go:noinline
|
||
|
|
func f() {
|
||
|
|
// The compiler optimizes this to direct copying
|
||
|
|
// the call result to both globals, with write
|
||
|
|
// barriers. The first write barrier call clobbers
|
||
|
|
// the result of g on stack.
|
||
|
|
X = g()
|
||
|
|
Y = X
|
||
|
|
}
|
||
|
|
|
||
|
|
var X, Y T
|
||
|
|
|
||
|
|
const N = 1000
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
// Keep GC running so the write barrier is on.
|
||
|
|
go func() {
|
||
|
|
for {
|
||
|
|
runtime.GC()
|
||
|
|
}
|
||
|
|
}()
|
||
|
|
|
||
|
|
for i := 0; i < N; i++ {
|
||
|
|
runtime.Gosched()
|
||
|
|
f()
|
||
|
|
if X != Y {
|
||
|
|
panic("FAIL")
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|