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// run
// Copyright 2023 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.
package main
import (
"runtime"
"unsafe"
)
//go:noinline
func g(x *byte) *byte { return x }
func main() {
slice()
str("AAAAAAAA", "BBBBBBBBB")
}
func wait(done <-chan struct{}) bool {
for i := 0; i < 10; i++ {
runtime.GC()
select {
case <-done:
return true
default:
}
}
return false
}
func slice() {
s := make([]byte, 100)
s[0] = 1
one := unsafe.SliceData(s)
done := make(chan struct{})
runtime.SetFinalizer(one, func(*byte) { close(done) })
h := g(one)
if wait(done) {
panic("GC'd early")
}
if *h != 1 {
panic("lost one")
}
if !wait(done) {
panic("never GC'd")
}
}
var strDone = make(chan struct{})
//go:noinline
func str(x, y string) {
s := x + y // put in temporary on stack
p := unsafe.StringData(s)
runtime.SetFinalizer(p, func(*byte) { close(strDone) })
if wait(strDone) {
panic("GC'd early")
}
if *p != 'A' {
panic("lost p")
}
if !wait(strDone) {
panic("never GC'd")
}
}
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