[Heap] Remove concept of MarkingParity.

src/heap/mark-compact.cc

 // 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.
 
 #include "src/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 35 matching lines @@
 // -------------------------------------------------------------------------
 // MarkCompactCollector
 
 MarkCompactCollector::MarkCompactCollector(Heap* heap)
     :  // NOLINT
       heap_(heap),
       page_parallel_job_semaphore_(0),
 #ifdef DEBUG
       state_(IDLE),
 #endif
-      marking_parity_(ODD_MARKING_PARITY),
       was_marked_incrementally_(false),
       evacuation_(false),
       compacting_(false),
       black_allocation_(false),
       have_code_to_deoptimize_(false),
       marking_deque_(heap),
       code_flusher_(nullptr),
       sweeper_(heap) {
 }
 
@@ skipping 798 matching lines @@
   isolate()->load_stub_cache()->Clear();
   isolate()->store_stub_cache()->Clear();
 
   if (have_code_to_deoptimize_) {
     // Some code objects were marked for deoptimization during the GC.
     Deoptimizer::DeoptimizeMarkedCode(isolate());
     have_code_to_deoptimize_ = false;
   }
 
   heap_->incremental_marking()->ClearIdleMarkingDelayCounter();
-
-  if (marking_parity_ == EVEN_MARKING_PARITY) {
-    marking_parity_ = ODD_MARKING_PARITY;
-  } else {
-    DCHECK(marking_parity_ == ODD_MARKING_PARITY);
-    marking_parity_ = EVEN_MARKING_PARITY;
-  }
 }
 
 
 // -------------------------------------------------------------------------
 // Phase 1: tracing and marking live objects.
 //   before: all objects are in normal state.
 //   after: a live object's map pointer is marked as '00'.
 
 // Marking all live objects in the heap as part of mark-sweep or mark-compact
 // collection.  Before marking, all objects are in their normal state.  After
@@ skipping 3196 matching lines @@
       // The target is always in old space, we don't have to record the slot in
       // the old-to-new remembered set.
       DCHECK(!heap()->InNewSpace(target));
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8