some random isolate threading

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 1770 matching lines @@
     MarkObject(code, code_mark);
     if (frame->is_optimized()) {
       MarkCompactMarkingVisitor::MarkInlinedFunctionsCode(heap(),
                                                           frame->LookupCode());
     }
   }
 }
 
 
 void MarkCompactCollector::PrepareForCodeFlushing() {
-  ASSERT(heap() == Isolate::Current()->heap());
-
   // Enable code flushing for non-incremental cycles.
   if (FLAG_flush_code && !FLAG_flush_code_incrementally) {
     EnableCodeFlushing(!was_marked_incrementally_);
   }
 
   // If code flushing is disabled, there is no need to prepare for it.
   if (!is_code_flushing_enabled()) return;
 
   // Ensure that empty descriptor array is marked. Method MarkDescriptorArray
   // relies on it being marked before any other descriptor array.
@@ skipping 2511 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal