golang issue30977 代码
文件路径：/test/fixedbugs/issue30977.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")
}
}
}