runtime: add optional expensive check for invalid cgo pointer passing
If you set GODEBUG=cgocheck=2 the runtime package will use the write
barrier to detect cases where a Go program writes a Go pointer into
non-Go memory. In conjunction with the existing cgo checks, and the
not-yet-implemented cgo check for exported functions, this should
reliably detect all cases (that do not import the unsafe package) in
which a Go pointer is incorrectly shared with C code. This check is
optional because it turns on the write barrier at all times, which is
known to be expensive.
Update #12416.
Change-Id: I549d8b2956daa76eac853928e9280e615d6365f4
Reviewed-on: https://go-review.googlesource.com/16899
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/src/cmd/compile/internal/gc/builtin/runtime.go b/src/cmd/compile/internal/gc/builtin/runtime.go
index 9301757..a50fc2e 100644
--- a/src/cmd/compile/internal/gc/builtin/runtime.go
+++ b/src/cmd/compile/internal/gc/builtin/runtime.go
@@ -108,7 +108,11 @@
func chansend1(chanType *byte, hchan chan<- any, elem *any)
func closechan(hchan any)
-var writeBarrierEnabled bool
+var writeBarrier struct {
+ enabled bool
+ needed bool
+ cgo bool
+}
func writebarrierptr(dst *any, src any)
func writebarrierstring(dst *any, src any)
