runtime: add GODEBUG for stack barriers at every frame
Currently enabling the debugging mode where stack barriers are
installed at every frame requires recompiling the runtime. However,
this is potentially useful for field debugging and for runtime tests,
so make this mode a GODEBUG.
Updates #12238.
Change-Id: I6fb128f598b19568ae723a612e099c0ed96917f5
Reviewed-on: https://go-review.googlesource.com/13947
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/src/runtime/mgcmark.go b/src/runtime/mgcmark.go
index 650d038..44f9512 100644
--- a/src/runtime/mgcmark.go
+++ b/src/runtime/mgcmark.go
@@ -341,7 +341,7 @@
switch gcphase {
case _GCscan:
// Install stack barriers during stack scan.
- barrierOffset = firstStackBarrierOffset
+ barrierOffset = uintptr(firstStackBarrierOffset)
nextBarrier = sp + barrierOffset
if debug.gcstackbarrieroff > 0 {
