[heap] Fix computation of flags offset in memorychunk

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index cd207bcda27ba792ec2291abead68006c86932be..c726fe53fe876c5461e98f0d744525747eca477f 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -400,6 +400,99 @@ class MarkCompactCollector {
  public:
   class Evacuator;
 
+  class Sweeper {
+   public:
+    class SweeperTask;
+
+    enum SweepingMode { SWEEP_ONLY, SWEEP_AND_VISIT_LIVE_OBJECTS };
+    enum SkipListRebuildingMode { REBUILD_SKIP_LIST, IGNORE_SKIP_LIST };
+    enum FreeSpaceTreatmentMode { IGNORE_FREE_SPACE, ZAP_FREE_SPACE };
+    enum SweepingParallelism { SWEEP_ON_MAIN_THREAD, SWEEP_IN_PARALLEL };
+
+    typedef std::vector<Page*> SweepingList;
+    typedef List<Page*> SweptList;
+
+    enum SweepingSpace {
+      kOldSpace,
+      kCodeSpace,
+      kMapSpace,
+      kNumberOfSweepingSpaces,
+    };
+
+    template <SweepingMode sweeping_mode, SweepingParallelism parallelism,
+              SkipListRebuildingMode skip_list_mode,
+              FreeSpaceTreatmentMode free_space_mode>
+    static int UnmanagedSweep(PagedSpace* space, Page* p, ObjectVisitor* v);
+
+    explicit Sweeper(Heap* heap)
+        : heap_(heap),
+          pending_sweeper_tasks_semaphore_(0),
+          sweeping_in_progress_(false) {}
+
+    bool sweeping_in_progress() { return sweeping_in_progress_; }
+
+    void AddPage(PagedSpace* space, Page* page);
+    void AddLatePage(SweepingSpace space, Page* page);
+    void CommitLateList(SweepingSpace space);
+
+    int HelpSweepInParallel(Page* page, PagedSpace* space);
+    int HelpSweepInParallel(PagedSpace* space, int required_freed_bytes,
+                            int max_pages = 0);
+
+    void StartSweeping();
+    void SweepOrWaitUntilSweepingCompleted(Page* page);
+    void EnsureCompleted();
+    bool IsSweepingCompleted();
+    void ParallelSweepSpacesComplete();
+
+    void AddSweptPageSafe(PagedSpace* space, Page* page);
+    Page* GetSweptPage(PagedSpace* space);
+
+   private:
+    AllocationSpace allocation_space(SweepingSpace space) {
+      switch (space) {
+        case kOldSpace:
+          return OLD_SPACE;
+        case kCodeSpace:
+          return CODE_SPACE;
+        case kMapSpace:
+          return MAP_SPACE;
+        default:
+          UNREACHABLE();
+      }
+      UNREACHABLE();
+      return OLD_SPACE;
+    }
+
+    SweepingSpace sweeping_space(AllocationSpace space) {
+      switch (space) {
+        case OLD_SPACE:
+          return kOldSpace;
+        case CODE_SPACE:
+          return kCodeSpace;
+        case MAP_SPACE:
+          return kMapSpace;
+        default:
+          UNREACHABLE();
+      }
+      UNREACHABLE();
+      return kOldSpace;
+    }
+
+    void PrepareAddPage(SweepingSpace space, Page* page);
+
+    Heap* heap_;
+    base::Mutex mutex_;
+    base::Semaphore pending_sweeper_tasks_semaphore_;
+    SweptList swept_list_[kNumberOfSweepingSpaces];
+    SweepingList sweeping_list_[kNumberOfSweepingSpaces];
+    SweepingList* late_sweeping_list_[kNumberOfSweepingSpaces];
+    SweepingList* tmp_late_sweeping_list_[kNumberOfSweepingSpaces];
+    bool sweeping_in_progress_;
+
+    friend class SweeperTask;
+  };
+
   enum IterationMode {
     kKeepMarking,
     kClearMarkbits,
@@ -490,38 +583,19 @@ class MarkCompactCollector {
 
   MarkingParity marking_parity() { return marking_parity_; }
 
-  // Concurrent and parallel sweeping support. If required_freed_bytes was set
-  // to a value larger than 0, then sweeping returns after a block of at least
-  // required_freed_bytes was freed. If required_freed_bytes was set to zero
-  // then the whole given space is swept. It returns the size of the maximum
-  // continuous freed memory chunk.
-  int SweepInParallel(PagedSpace* space, int required_freed_bytes,
-                      int max_pages = 0);
-
-  // Sweeps a given page concurrently to the sweeper threads. It returns the
-  // size of the maximum continuous freed memory chunk.
-  int SweepInParallel(Page* page, PagedSpace* space);
-
   // Ensures that sweeping is finished.
   //
   // Note: Can only be called safely from main thread.
   void EnsureSweepingCompleted();
 
-  void SweepOrWaitUntilSweepingCompleted(Page* page);
-
   // Help out in sweeping the corresponding space and refill memory that has
   // been regained.
   //
   // Note: Thread-safe.
   void SweepAndRefill(CompactionSpace* space);
 
-  // If sweeper threads are not active this method will return true. If
-  // this is a latency issue we should be smarter here. Otherwise, it will
-  // return true if the sweeper threads are done processing the pages.
-  bool IsSweepingCompleted();
-
   // Checks if sweeping is in progress right now on any space.
-  bool sweeping_in_progress() { return sweeping_in_progress_; }
+  bool sweeping_in_progress() { return sweeper().sweeping_in_progress(); }
 
   void set_evacuation(bool evacuation) { evacuation_ = evacuation; }
 
@@ -562,27 +636,13 @@ class MarkCompactCollector {
   // address range.
   void RemoveObjectSlots(Address start_slot, Address end_slot);
 
-  base::Mutex* swept_pages_mutex() { return &swept_pages_mutex_; }
-  List<Page*>* swept_pages(AllocationSpace id) {
-    switch (id) {
-      case OLD_SPACE:
-        return &swept_old_space_pages_;
-      case CODE_SPACE:
-        return &swept_code_space_pages_;
-      case MAP_SPACE:
-        return &swept_map_space_pages_;
-      default:
-        UNREACHABLE();
-    }
-    return nullptr;
-  }
+  Sweeper& sweeper() { return sweeper_; }
 
  private:
   class EvacuateNewSpaceVisitor;
   class EvacuateOldSpaceVisitor;
   class EvacuateVisitorBase;
   class HeapObjectVisitor;
-  class SweeperTask;
 
   typedef std::vector<Page*> SweepingList;
 
@@ -591,8 +651,6 @@ class MarkCompactCollector {
   bool WillBeDeoptimized(Code* code);
   void ClearInvalidRememberedSetSlots();
 
-  void StartSweeperThreads();
-
   void ComputeEvacuationHeuristics(int area_size,
                                    int* target_fragmentation_percent,
                                    int* max_evacuated_bytes);
@@ -761,8 +819,6 @@ class MarkCompactCollector {
   //          evacuation.
   //
 
-  inline SweepingList& sweeping_list(Space* space);
-
   // If we are not compacting the heap, we simply sweep the spaces except
   // for the large object space, clearing mark bits and adding unmarked
   // regions to each space's free list.
@@ -797,10 +853,6 @@ class MarkCompactCollector {
   // up other pages for sweeping.
   void StartSweepSpace(PagedSpace* space);
 
-  // Finalizes the parallel sweeping phase. Marks all the pages that were
-  // swept in parallel.
-  void ParallelSweepSpacesComplete();
-
 #ifdef DEBUG
   friend class MarkObjectVisitor;
   static void VisitObject(HeapObject* obj);
@@ -819,30 +871,17 @@ class MarkCompactCollector {
   List<Page*> evacuation_candidates_;
   List<NewSpacePage*> newspace_evacuation_candidates_;
 
-  base::Mutex swept_pages_mutex_;
-  List<Page*> swept_old_space_pages_;
-  List<Page*> swept_code_space_pages_;
-  List<Page*> swept_map_space_pages_;
-
-  SweepingList sweeping_list_old_space_;
-  SweepingList sweeping_list_code_space_;
-  SweepingList sweeping_list_map_space_;
-
   // True if we are collecting slots to perform evacuation from evacuation
   // candidates.
   bool compacting_;
 
-  // True if concurrent or parallel sweeping is currently in progress.
-  bool sweeping_in_progress_;
-
-  // Semaphore used to synchronize sweeper tasks.
-  base::Semaphore pending_sweeper_tasks_semaphore_;
-
   // Semaphore used to synchronize compaction tasks.
   base::Semaphore pending_compaction_tasks_semaphore_;
 
   bool black_allocation_;
 
+  Sweeper sweeper_;
+
   friend class Heap;
   friend class StoreBuffer;
 };