mirror of
https://github.com/golang/go
synced 2024-09-23 21:20:13 -06:00
cmd/compile: clear hidden value at end of channel range body
While we’re here, clean up a few comments. Fixes #15281 Change-Id: Ia6173e9941133db08f57bc80bdd3c5722122bfdb Reviewed-on: https://go-review.googlesource.com/22082 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
parent
24bd465bca
commit
644493f109
@ -154,7 +154,7 @@ func walkrange(n *Node) {
|
||||
v2 = n.List.Second()
|
||||
}
|
||||
|
||||
// n->list has no meaning anymore, clear it
|
||||
// n.List has no meaning anymore, clear it
|
||||
// to avoid erroneous processing by racewalk.
|
||||
n.List.Set(nil)
|
||||
|
||||
@ -217,9 +217,9 @@ func walkrange(n *Node) {
|
||||
n.Right.Ninit.Set1(a)
|
||||
}
|
||||
|
||||
// orderstmt allocated the iterator for us.
|
||||
// we only use a once, so no copy needed.
|
||||
case TMAP:
|
||||
// orderstmt allocated the iterator for us.
|
||||
// we only use a once, so no copy needed.
|
||||
ha := a
|
||||
|
||||
th := hiter(t)
|
||||
@ -254,8 +254,8 @@ func walkrange(n *Node) {
|
||||
body = []*Node{a}
|
||||
}
|
||||
|
||||
// orderstmt arranged for a copy of the channel variable.
|
||||
case TCHAN:
|
||||
// orderstmt arranged for a copy of the channel variable.
|
||||
ha := a
|
||||
|
||||
n.Left = nil
|
||||
@ -278,9 +278,13 @@ func walkrange(n *Node) {
|
||||
} else {
|
||||
body = []*Node{Nod(OAS, v1, hv1)}
|
||||
}
|
||||
// Zero hv1. This prevents hv1 from being the sole, inaccessible
|
||||
// reference to an otherwise GC-able value during the next channel receive.
|
||||
// See issue 15281.
|
||||
body = append(body, Nod(OAS, hv1, nil))
|
||||
|
||||
// orderstmt arranged for a copy of the string variable.
|
||||
case TSTRING:
|
||||
// orderstmt arranged for a copy of the string variable.
|
||||
ha := a
|
||||
|
||||
ohv1 := temp(Types[TINT])
|
||||
|
64
test/fixedbugs/issue15281.go
Normal file
64
test/fixedbugs/issue15281.go
Normal file
@ -0,0 +1,64 @@
|
||||
// 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.
|
||||
package main
|
||||
|
||||
import "runtime"
|
||||
|
||||
func main() {
|
||||
{
|
||||
x := inuse()
|
||||
c := make(chan []byte, 10)
|
||||
c <- make([]byte, 10<<20)
|
||||
close(c)
|
||||
f1(c, x)
|
||||
}
|
||||
{
|
||||
x := inuse()
|
||||
c := make(chan []byte, 10)
|
||||
c <- make([]byte, 10<<20)
|
||||
close(c)
|
||||
f2(c, x)
|
||||
}
|
||||
}
|
||||
|
||||
func f1(c chan []byte, start int64) {
|
||||
for x := range c {
|
||||
if delta := inuse() - start; delta < 9<<20 {
|
||||
println("BUG: f1: after alloc: expected delta at least 9MB, got: ", delta)
|
||||
println(x)
|
||||
}
|
||||
x = nil
|
||||
if delta := inuse() - start; delta > 1<<20 {
|
||||
println("BUG: f1: after alloc: expected delta below 1MB, got: ", delta)
|
||||
println(x)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func f2(c chan []byte, start int64) {
|
||||
for {
|
||||
x, ok := <-c
|
||||
if !ok {
|
||||
break
|
||||
}
|
||||
if delta := inuse() - start; delta < 9<<20 {
|
||||
println("BUG: f2: after alloc: expected delta at least 9MB, got: ", delta)
|
||||
println(x)
|
||||
}
|
||||
x = nil
|
||||
if delta := inuse() - start; delta > 1<<20 {
|
||||
println("BUG: f2: after alloc: expected delta below 1MB, got: ", delta)
|
||||
println(x)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func inuse() int64 {
|
||||
runtime.GC()
|
||||
var st runtime.MemStats
|
||||
runtime.ReadMemStats(&st)
|
||||
return int64(st.Alloc)
|
||||
}
|
Loading…
Reference in New Issue
Block a user