Introduce --zap-cpp-pointers (off by default)

src/heap/heap-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_INL_H_
 #define V8_HEAP_HEAP_INL_H_
 
 #include <cmath>
 
 #include "src/base/platform/platform.h"
@@ skipping 287 matching lines @@
   DCHECK(AllowHandleAllocation::IsAllowed());
   DCHECK(AllowHeapAllocation::IsAllowed());
   DCHECK(gc_state_ == NOT_IN_GC);
 #ifdef DEBUG
   if (FLAG_gc_interval >= 0 && !always_allocate() &&
       Heap::allocation_timeout_-- <= 0) {
     return AllocationResult::Retry(space);
   }
   isolate_->counters()->objs_since_last_full()->Increment();
   isolate_->counters()->objs_since_last_young()->Increment();
+
+// TODO(jkummerow): Handlify more of heap.cc to maintain the rule that
+// "there are no raw pointers anywhere on the stack when an allocation
+// is happening", and then remove the ZapHeapPointersInCppFrames() call
+// from CALL_HEAP_FUNCTION and instead enable it here.
+
+// if (FLAG_zap_cpp_pointers) ZapHeapPointersInCppFrames(isolate_);
 #endif
 
   bool large_object = size_in_bytes > kMaxRegularHeapObjectSize;
   HeapObject* object = nullptr;
   AllocationResult allocation;
   if (NEW_SPACE == space) {
     if (large_object) {
       space = LO_SPACE;
     } else {
       allocation = new_space_->AllocateRaw(size_in_bytes, alignment);
@@ skipping 559 matching lines @@
 void VerifySmisVisitor::VisitRootPointers(Root root, Object** start,
                                           Object** end) {
   for (Object** current = start; current < end; current++) {
     CHECK((*current)->IsSmi());
   }
 }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_INL_H_