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https://github.com/golang/go
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54 lines
1.1 KiB
Go
54 lines
1.1 KiB
Go
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// run
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// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// issue 16515: spilled Duff-adjusted address may be invalid
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package main
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import "runtime"
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type T [62]int // DUFFZERO with non-zero adjustment on AMD64
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var sink interface{}
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//go:noinline
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func zero(x *T) {
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// Two DUFFZEROs on the same address with a function call in between.
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// Duff-adjusted address will be spilled and loaded
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*x = T{} // DUFFZERO
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runtime.GC()
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(*x)[0] = 1
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g() // call a function with large frame, trigger a stack move
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*x = T{} // DUFFZERO again
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}
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//go:noinline
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// a function with large frame
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func g() {
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var x [1000]int
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_ = x
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}
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func main() {
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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
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sink = &s // force heap allocation
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s.a[0] = 2
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zero(&s.a)
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if s.a[0] != 0 {
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println("s.a[0] =", s.a[0])
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panic("zeroing failed")
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}
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var a T // on stack
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a[0] = 2
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zero(&a)
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if a[0] != 0 {
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println("a[0] =", a[0])
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panic("zeroing failed")
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}
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}
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