v8: make GCTracer persistent.

src/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_MARK_COMPACT_H_
 #define V8_MARK_COMPACT_H_
 
 #include "src/compiler-intrinsics.h"
 #include "src/spaces.h"
 
@@ skipping 510 matching lines @@
   void SetUp();
 
   void TearDown();
 
   void CollectEvacuationCandidates(PagedSpace* space);
 
   void AddEvacuationCandidate(Page* p);
 
   // Prepares for GC by resetting relocation info in old and map spaces and
   // choosing spaces to compact.
-  void Prepare(GCTracer* tracer);
+  void Prepare();
 
   // Performs a global garbage collection.
   void CollectGarbage();
 
   enum CompactionMode {
     INCREMENTAL_COMPACTION,
     NON_INCREMENTAL_COMPACTION
   };
 
   bool StartCompaction(CompactionMode mode);
 
   void AbortCompaction();
 
-  // During a full GC, there is a stack-allocated GCTracer that is used for
-  // bookkeeping information.  Return a pointer to that tracer.
-  GCTracer* tracer() { return tracer_; }
-
 #ifdef DEBUG
   // Checks whether performing mark-compact collection.
   bool in_use() { return state_ > PREPARE_GC; }
   bool are_map_pointers_encoded() { return state_ == UPDATE_POINTERS; }
 #endif
 
   // Determine type of object and emit deletion log event.
   static void ReportDeleteIfNeeded(HeapObject* obj, Isolate* isolate);
 
   // Distinguishable invalid map encodings (for single word and multiple words)
@@ skipping 179 matching lines @@
 
   bool was_marked_incrementally_;
 
   // True if concurrent or parallel sweeping is currently in progress.
   bool sweeping_pending_;
 
   base::Semaphore pending_sweeper_jobs_semaphore_;
 
   bool sequential_sweeping_;
 
-  // A pointer to the current stack-allocated GC tracer object during a full
-  // collection (NULL before and after).
-  GCTracer* tracer_;
-
   SlotsBufferAllocator slots_buffer_allocator_;
 
   SlotsBuffer* migration_slots_buffer_;
 
   // Finishes GC, performs heap verification if enabled.
   void Finish();
 
   // -----------------------------------------------------------------------
   // Phase 1: Marking live objects.
   //
@@ skipping 223 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_