qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-22 13:24:53 -07:00
Code Releases Activity

cmd/compile: add write barrier to type switch

Browse Source 
Type switches need write barriers if the written-to
variable is heap allocated.

For the added needwritebarrier call, the right arg doesn't
really matter, I just pass something that will never disqualify
the write barrier.  The left arg is the one that matters.

Fixes #14306

Change-Id: Ic2754167cce062064ea2eeac2944ea4f77cc9c3b
Reviewed-on: https://go-review.googlesource.com/19481
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Keith Randall 2016-02-12 10:07:36 -08:00
parent c93193aec0
commit e3033fc535
2 changed files with 15 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/cmd/compile/internal/gc/gen.go
View File

@ -836,7 +836,7 @@ func gen(n *Node) {
Cgen_as_wb(n.Left, n.Right, true)
case OAS2DOTTYPE:
cgen_dottype(n.Rlist.N, n.List.N, n.List.Next.N, false)
cgen_dottype(n.Rlist.N, n.List.N, n.List.Next.N, needwritebarrier(n.List.N, n.Rlist.N))
case OCALLMETH:
cgen_callmeth(n, 0)

14
test/writebarrier.go
View File

@ -144,3 +144,17 @@ type T8 struct {
func f16(x []T8, y T8) []T8 {
return append(x, y) // ERROR "write barrier"
}
func t1(i interface{}) **int {
// From issue 14306, make sure we have write barriers in a type switch
// where the assigned variable escapes.
switch x := i.(type) { // ERROR "write barrier"
case *int:
return &x
}
switch y := i.(type) { // no write barrier here
case **int:
return y
}
return nil
}