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go/test/fixedbugs/issue17449.go
Dhananjay Nakrani 8b3194ac8f cmd/compile: fix code duplication in race-instrumentation
instrumentnode() accidentally copies parent's already-instrumented nodes
into child's Ninit block. This generates repeated code in race-instrumentation.
This case surfaces only when it duplicates inline-labels, because of
compile time error. In other cases, it silently generates incorrect
instrumented code. This change prevents it from doing so.

Fixes #17449.

Change-Id: Icddf2198990442166307e176b7e20aa0cf6c171c
Reviewed-on: https://go-review.googlesource.com/31317
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-18 20:11:01 +00:00

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Go

// errorcheck -0 -race
// 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 17449: race instrumentation copies over previous instrumented nodes from parents block into child's Ninit block.
// This code surfaces the duplication at compile time because of generated inline labels.
package master
type PriorityList struct {
elems []interface{}
}
func (x *PriorityList) Len() int { return len(x.elems) }
func (l *PriorityList) remove(i int) interface{} {
elem := l.elems[i]
l.elems = append(l.elems[:i], l.elems[i+1:]...)
return elem
}
func (l *PriorityList) Next() interface{} {
return l.remove(l.Len() - 1)
}
var l *PriorityList
func Foo() {
// It would fail here if instrumented code (including inline-label) was copied.
for elem := l.Next(); elem != nil; elem = l.Next() {
}
}