compiler: check for notinheap struct at each struct field
When generating write barriers, we were only checking for a notinheap
struct at the outermost struct. That mishandled the case of setting a
pointer to a notinheap struct as a field of another struct that is not
notinheap. This caused an invalid write barrier error when building
the 1.13 version of the runtime.
Change-Id: Ib3ccb8d70fd46d81839372d6b43530994b4d2441
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/192279
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/go/wb.cc b/go/wb.cc
index 41d8f94..1eadb3e 100644
--- a/go/wb.cc
+++ b/go/wb.cc
@@ -733,6 +733,31 @@
&& !lhs->type()->points_to()->in_heap())
return false;
+ // For a struct assignment, we don't need a write barrier if all
+ // the field types can not be in the heap.
+ Struct_type* st = lhs->type()->struct_type();
+ if (st != NULL)
+ {
+ bool in_heap = false;
+ const Struct_field_list* fields = st->fields();
+ for (Struct_field_list::const_iterator p = fields->begin();
+ p != fields->end();
+ p++)
+ {
+ Type* ft = p->type();
+ if (!ft->has_pointer())
+ continue;
+ if (!ft->in_heap())
+ continue;
+ if (ft->points_to() != NULL && !ft->points_to()->in_heap())
+ continue;
+ in_heap = true;
+ break;
+ }
+ if (!in_heap)
+ return false;
+ }
+
Field_reference_expression* fre = lhs->field_reference_expression();
if (fre != NULL)
{
@@ -788,31 +813,6 @@
&& this->is_nonwb_pointer(ue->operand(), nonwb_pointers))
return false;
- // For a struct assignment, we don't need a write barrier if all the
- // pointer types can not be in the heap.
- Struct_type* st = lhs->type()->struct_type();
- if (st != NULL)
- {
- bool in_heap = false;
- const Struct_field_list* fields = st->fields();
- for (Struct_field_list::const_iterator p = fields->begin();
- p != fields->end();
- p++)
- {
- Type* ft = p->type();
- if (!ft->has_pointer())
- continue;
- if (!ft->in_heap())
- continue;
- if (ft->points_to() != NULL && !ft->points_to()->in_heap())
- continue;
- in_heap = true;
- break;
- }
- if (!in_heap)
- return false;
- }
-
// Write barrier needed in other cases.
return true;
}
