Disallow heap objects containing unsafe on-heap iterators.

tools/clang/blink_gc_plugin/CheckFieldsVisitor.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "CheckFieldsVisitor.h"
 
 #include <cassert>
 
 #include "BlinkGCPluginOptions.h"
 #include "RecordInfo.h"
@@ skipping 29 matching lines @@
   // A member is allowed to appear in the context of a root.
   for (Context::iterator it = context().begin();
        it != context().end();
        ++it) {
     if ((*it)->Kind() == Edge::kRoot)
       return;
   }
   invalid_fields_.push_back(std::make_pair(current_, kMemberInUnmanaged));
 }
 
+void CheckFieldsVisitor::AtIterator(Iterator* edge) {
+  if (!managed_host_)
+    return;
+
+  if (edge->IsUnsafe())
+    invalid_fields_.push_back(std::make_pair(current_, kIteratorToGCManaged));
+}
+
 void CheckFieldsVisitor::AtValue(Value* edge) {
   // TODO: what should we do to check unions?
   if (edge->value()->record()->isUnion())
     return;
 
   if (!stack_allocated_host_ && edge->value()->IsStackAllocated()) {
     invalid_fields_.push_back(std::make_pair(current_, kPtrFromHeapToStack));
     return;
   }
 
@@ skipping 56 matching lines @@
       return kRawPtrToGCManaged;
   }
   if (ptr->IsRefPtr())
     return kRefPtrToGCManaged;
   if (ptr->IsOwnPtr())
     return kOwnPtrToGCManaged;
   if (ptr->IsUniquePtr())
     return kUniquePtrToGCManaged;
   assert(false && "Unknown smart pointer kind");
 }