[vm, gc] Require a safepoint for heap iteration.

runtime/vm/profiler.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/address_sanitizer.h"
 #include "platform/memory_sanitizer.h"
 #include "platform/utils.h"
 
 #include "vm/allocation.h"
 #include "vm/atomic.h"
@@ skipping 1409 matching lines @@
   ASSERT(thread != NULL);
   Isolate* isolate = thread->isolate();
   ASSERT(isolate != NULL);
   Isolate* vm_isolate = Dart::vm_isolate();
   ASSERT(vm_isolate != NULL);
 
   // Clear.
   code_objects_.Clear();
 
   // Add all found Code objects.
-  CodeLookupTableBuilder cltb(this);
-  vm_isolate->heap()->IterateOldObjects(&cltb);
-  isolate->heap()->IterateOldObjects(&cltb);
+  {
+    HeapIterationScope iteration;
+    CodeLookupTableBuilder cltb(this);
+    iteration.IterateVMIsolateObjects(&cltb);
+    iteration.IterateOldObjects(&cltb);
+  }
 
   // Sort by entry.
   code_objects_.Sort(CodeDescriptor::Compare);
 
 #if defined(DEBUG)
   if (length() <= 1) {
     return;
   }
   ASSERT(FindCode(0) == NULL);
   ASSERT(FindCode(~0) == NULL);
@@ skipping 238 matching lines @@
 }
 
 ProcessedSampleBuffer::ProcessedSampleBuffer()
     : code_lookup_table_(new CodeLookupTable(Thread::Current())) {
   ASSERT(code_lookup_table_ != NULL);
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart