go issue16515 源码
golang issue16515 代码
文件路径：/test/fixedbugs/issue16515.go
// run
// Copyright 2016 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 16515: spilled Duff-adjusted address may be invalid
package main
import "runtime"
type T [62]int // DUFFZERO with non-zero adjustment on AMD64
var sink interface{}
//go:noinline
func zero(x *T) {
// Two DUFFZEROs on the same address with a function call in between.
// Duff-adjusted address will be spilled and loaded
*x = T{} // DUFFZERO
runtime.GC()
(*x)[0] = 1
g() // call a function with large frame, trigger a stack move
*x = T{} // DUFFZERO again
}
//go:noinline
// a function with large frame
func g() {
var x [1000]int
_ = x
}
func main() {
var s struct { a T; b [8192-62]int } // allocate 64K, hopefully it's in a new span and a few bytes before it is garbage
sink = &s // force heap allocation
s.a[0] = 2
zero(&s.a)
if s.a[0] != 0 {
println("s.a[0] =", s.a[0])
panic("zeroing failed")
}
var a T // on stack
a[0] = 2
zero(&a)
if a[0] != 0 {
println("a[0] =", a[0])
panic("zeroing failed")
}
}
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