// run
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// Copyright 2018 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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// This test makes sure that ambiguously live arguments work correctly.
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package main
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import (
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"runtime"
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)
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type HeapObj [8]int64
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type StkObj struct {
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h *HeapObj
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}
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var n int
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var c int = -1
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func gc() {
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// encourage heap object to be collected, and have its finalizer run.
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runtime.GC()
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runtime.GC()
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runtime.GC()
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n++
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}
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var null StkObj
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var sink *HeapObj
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//go:noinline
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func use(p *StkObj) {
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}
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//go:noinline
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func f(s StkObj, b bool) {
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var p *StkObj
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if b {
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p = &s
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} else {
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p = &null
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}
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// use is required here to prevent the conditional
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// code above from being executed after the first gc() call.
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use(p)
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// If b==false, h should be collected here.
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gc() // 0
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sink = p.h
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gc() // 1
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sink = nil
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// If b==true, h should be collected here.
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gc() // 2
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}
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func fTrue() {
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var s StkObj
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s.h = new(HeapObj)
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c = -1
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n = 0
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runtime.SetFinalizer(s.h, func(h *HeapObj) {
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// Remember at what phase the heap object was collected.
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c = n
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})
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f(s, true)
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if c != 2 {
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panic("bad liveness")
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}
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}
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func fFalse() {
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var s StkObj
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s.h = new(HeapObj)
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c = -1
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n = 0
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runtime.SetFinalizer(s.h, func(h *HeapObj) {
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// Remember at what phase the heap object was collected.
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c = n
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})
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f(s, false)
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if c != 0 {
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panic("bad liveness")
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}
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}
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func main() {
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fTrue()
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fFalse()
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}
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