Add sanity check to CodeFlusher::AddCandidate.

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 915 matching lines @@
     isolate_->heap()->mark_compact_collector()->
         RecordSlot(code_slot, code_slot, *code_slot);
 
     candidate = next_candidate;
   }
 
   shared_function_info_candidates_head_ = NULL;
 }
 
 
+bool CodeFlusher::ContainsCandidate(SharedFunctionInfo* shared_info) {
+  SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
+  while (candidate != NULL) {
+    if (candidate == shared_info) return true;
+    candidate = GetNextCandidate(candidate);
+  }
+  return false;
+}
+
+
 void CodeFlusher::EvictCandidate(SharedFunctionInfo* shared_info) {
   // The function is no longer a candidate, make sure it gets visited
   // again so that previous flushing decisions are revisited.
   isolate_->heap()->incremental_marking()->RecordWrites(shared_info);
 
   SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
   SharedFunctionInfo* next_candidate;
   if (candidate == shared_info) {
     next_candidate = GetNextCandidate(shared_info);
     shared_function_info_candidates_head_ = next_candidate;
@@ skipping 2897 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal