Reset the path tracer completely, and check whether an object has source code before trying to print

src/heap.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 6445 matching lines @@
 void PathTracer::Reset() {
   found_target_ = false;
   object_stack_.Clear();
 }
 
 
 void PathTracer::TracePathFrom(Object** root) {
   ASSERT((search_target_ == kAnyGlobalObject) ||
          search_target_->IsHeapObject());
   found_target_in_trace_ = false;
-  object_stack_.Clear();
+  Reset();
 
   MarkVisitor mark_visitor(this);
   MarkRecursively(root, &mark_visitor);
 
   UnmarkVisitor unmark_visitor(this);
   UnmarkRecursively(root, &unmark_visitor);
 
   ProcessResults();
 }
 
@@ skipping 83 matching lines @@
 void PathTracer::ProcessResults() {
   if (found_target_) {
     PrintF("=====================================\n");
     PrintF("====        Path to object       ====\n");
     PrintF("=====================================\n\n");
 
     ASSERT(!object_stack_.is_empty());
     for (int i = 0; i < object_stack_.length(); i++) {
       if (i > 0) PrintF("\n     |\n     |\n     V\n\n");
       Object* obj = object_stack_[i];
-#ifdef OBJECT_PRINT
       obj->Print();
-#else
-      obj->ShortPrint();
-#endif
     }
     PrintF("=====================================\n");
   }
 }
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 
 #ifdef DEBUG
 // Triggers a depth-first traversal of reachable objects from roots
 // and finds a path to a specific heap object and prints it.
@@ skipping 395 matching lines @@
   } else {
     p ^= 0x1d1ed & (Page::kPageSize - 1);  // I died.
   }
   remembered_unmapped_pages_[remembered_unmapped_pages_index_] =
       reinterpret_cast<Address>(p);
   remembered_unmapped_pages_index_++;
   remembered_unmapped_pages_index_ %= kRememberedUnmappedPages;
 }
 
 } }  // namespace v8::internal