diff options
| author | Keith Randall <khr@golang.org> | 2025-01-10 17:33:26 -0800 |
|---|---|---|
| committer | Keith Randall <khr@golang.org> | 2025-01-12 22:49:39 -0800 |
| commit | 44a6f817ea0fbeb3ba4aa398794c4e80dba13b1e (patch) | |
| tree | bf8b97d89a07f0185ab42468d20b2e68887f4986 /test/codegen | |
| parent | 19e923182e590ae6568c2c714f20f32512aeb3e3 (diff) | |
| download | go-44a6f817ea0fbeb3ba4aa398794c4e80dba13b1e.tar.xz | |
cmd/compile: fix write barrier coalescing
We can't coalesce a non-WB store with a subsequent Move, as the
result of the store might be the source of the move.
There's a simple codegen test. Not sure how we might do a real test,
as all the repro's I've come up with are very expensive and unreliable.
Fixes #71228
Change-Id: If18bf181a266b9b90964e2591cd2e61a7168371c
Reviewed-on: https://go-review.googlesource.com/c/go/+/642197
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Diffstat (limited to 'test/codegen')
| -rw-r--r-- | test/codegen/writebarrier.go | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/test/codegen/writebarrier.go b/test/codegen/writebarrier.go index e125973e7c..e2b1399399 100644 --- a/test/codegen/writebarrier.go +++ b/test/codegen/writebarrier.go @@ -63,3 +63,28 @@ func trickyWriteNil(p *int, q **int) { *q = p } } + +type S struct { + a, b string + c *int +} + +var g1, g2 *int + +func issue71228(dst *S, ptr *int) { + // Make sure that the non-write-barrier write. + // "sp.c = ptr" happens before the large write + // barrier "*dst = *sp". We approximate testing + // that by ensuring that two global variable write + // barriers aren't combined. + _ = *dst + var s S + sp := &s + //amd64:`.*runtime[.]gcWriteBarrier1` + g1 = nil + sp.c = ptr // outside of any write barrier + //amd64:`.*runtime[.]gcWriteBarrier1` + g2 = nil + //amd64:`.*runtime[.]wbMove` + *dst = *sp +} |
