Replace slots buffer with remembered set.

src/heap/remembered-set.h

 // Copyright 2016 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_REMEMBERED_SET_H
 #define V8_REMEMBERED_SET_H
 
 #include "src/heap/heap.h"
 #include "src/heap/slot-set.h"
 #include "src/heap/spaces.h"
@@ skipping 38 matching lines @@
       uintptr_t start_offset = start - page->address();
       uintptr_t end_offset = end - page->address();
       DCHECK_LT(start_offset, end_offset);
       DCHECK_LE(end_offset, static_cast<uintptr_t>(Page::kPageSize));
       slot_set->RemoveRange(static_cast<uint32_t>(start_offset),
                             static_cast<uint32_t>(end_offset));
     }
   }
 
   // Iterates and filters the remembered set with the given callback.
-  // The callback should take (Address slot) and return SlotSet::CallbackResult.
+  // The callback should take (Address slot) and return SlotCallbackResult.
   template <typename Callback>
   static void Iterate(Heap* heap, Callback callback) {
-    PointerChunkIterator it(heap);
+    MemoryChunkIterator it(heap, direction == OLD_TO_OLD
+                                     ? MemoryChunkIterator::ALL
+                                     : MemoryChunkIterator::ALL_BUT_CODE_SPACE);
     MemoryChunk* chunk;
     while ((chunk = it.next()) != nullptr) {
       SlotSet* slots = GetSlotSet(chunk);
       if (slots != nullptr) {
         size_t pages = (chunk->size() + Page::kPageSize - 1) / Page::kPageSize;
         int new_count = 0;
         for (size_t page = 0; page < pages; page++) {
           new_count += slots[page].Iterate(callback);
         }
         if (new_count == 0) {
           ReleaseSlotSet(chunk);
         }
       }
     }
   }
 
   // Iterates and filters the remembered set with the given callback.
   // The callback should take (HeapObject** slot, HeapObject* target) and
   // update the slot.
   // A special wrapper takes care of filtering the slots based on their values.
   // For OLD_TO_NEW case: slots that do not point to the ToSpace after
   // callback invocation will be removed from the set.
   template <typename Callback>
   static void IterateWithWrapper(Heap* heap, Callback callback) {
     Iterate(heap, [heap, callback](Address addr) {
       return Wrapper(heap, addr, callback);
     });
   }
 
+  // Given a page and a typed slot in that page, this function adds the slot
+  // to the remembered set.
+  static void InsertTyped(Page* page, SlotType slot_type, Address slot_addr) {
+    STATIC_ASSERT(direction == OLD_TO_OLD);
+    TypedSlotSet* slot_set = page->typed_old_to_old_slots();
+    if (slot_set == nullptr) {
+      page->AllocateTypedOldToOldSlots();
+      slot_set = page->typed_old_to_old_slots();
+    }
+    uintptr_t offset = slot_addr - page->address();
+    DCHECK_LT(offset, static_cast<uintptr_t>(TypedSlotSet::kMaxOffset));
+    slot_set->Insert(slot_type, static_cast<uint32_t>(offset));
+  }
+
+  // Given a page and a range of typed slots in that page, this function removes
+  // the slots from the remembered set.
+  static void RemoveRangeTyped(Page* page, Address start, Address end) {
+    TypedSlotSet* slots = page->typed_old_to_old_slots();
+    if (slots != nullptr) {
+      slots->Iterate([start, end](SlotType slot_type, Address slot_addr) {
+        return start <= slot_addr && slot_addr < end ? REMOVE_SLOT : KEEP_SLOT;
+      });
+    }
+  }
+
+  // Iterates and filters typed old to old pointers with the given callback.
+  // The callback should take (SlotType slot_type, Address slot_addr) and
+  // return SlotCallbackResult.
+  template <typename Callback>
+  static void IterateTyped(Heap* heap, Callback callback) {
+    MemoryChunkIterator it(heap, MemoryChunkIterator::ALL_BUT_MAP_SPACE);
+    MemoryChunk* chunk;
+    while ((chunk = it.next()) != nullptr) {
+      TypedSlotSet* slots = chunk->typed_old_to_old_slots();
+      if (slots != nullptr) {
+        int new_count = slots->Iterate(callback);
+        if (new_count == 0) {
+          chunk->ReleaseTypedOldToOldSlots();
+        }
+      }
+    }
+  }
+
+  // Clear all old to old slots from the remembered set.
+  static void ClearAll(Heap* heap) {
+    STATIC_ASSERT(direction == OLD_TO_OLD);
+    MemoryChunkIterator it(heap, MemoryChunkIterator::ALL);
+    MemoryChunk* chunk;
+    while ((chunk = it.next()) != nullptr) {
+      chunk->ReleaseOldToOldSlots();
+      chunk->ReleaseTypedOldToOldSlots();
+    }
+  }
+
   // Eliminates all stale slots from the remembered set, i.e.
   // slots that are not part of live objects anymore. This method must be
   // called after marking, when the whole transitive closure is known and
   // must be called before sweeping when mark bits are still intact.
   static void ClearInvalidSlots(Heap* heap);
 
   static void VerifyValidSlots(Heap* heap);
 
  private:
   static SlotSet* GetSlotSet(MemoryChunk* chunk) {
@@ skipping 16 matching lines @@
     if (direction == OLD_TO_OLD) {
       chunk->AllocateOldToOldSlots();
       return chunk->old_to_old_slots();
     } else {
       chunk->AllocateOldToNewSlots();
       return chunk->old_to_new_slots();
     }
   }
 
   template <typename Callback>
-  static SlotSet::CallbackResult Wrapper(Heap* heap, Address slot_address,
-                                         Callback slot_callback) {
+  static SlotCallbackResult Wrapper(Heap* heap, Address slot_address,
+                                    Callback slot_callback) {
     STATIC_ASSERT(direction == OLD_TO_NEW);
     Object** slot = reinterpret_cast<Object**>(slot_address);
     Object* object = *slot;
     if (heap->InFromSpace(object)) {
       HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
       DCHECK(heap_object->IsHeapObject());
       slot_callback(reinterpret_cast<HeapObject**>(slot), heap_object);
       object = *slot;
       // If the object was in from space before and is after executing the
       // callback in to space, the object is still live.
       // Unfortunately, we do not know about the slot. It could be in a
       // just freed free space object.
       if (heap->InToSpace(object)) {
-        return SlotSet::KEEP_SLOT;
+        return KEEP_SLOT;
       }
     } else {
       DCHECK(!heap->InNewSpace(object));
     }
-    return SlotSet::REMOVE_SLOT;
+    return REMOVE_SLOT;
   }
 
   static bool IsValidSlot(Heap* heap, Object** slot);
 };
 
+// Buffer for keeping thead local migration slots during compation.

[jochen (gone - plz use gerrit), 2016/02/23 13:10:54]

compaction

[ulan, 2016/02/23 13:19:07]

Done.

+// TODO(ulan): Remove this once every thread gets local pages in compaction
+// space.
+class LocalSlotsBuffer BASE_EMBEDDED {
+ public:
+  LocalSlotsBuffer() : top_(new Node(nullptr)) {}
+
+  ~LocalSlotsBuffer() {
+    Node* current = top_;
+    while (current != nullptr) {
+      Node* tmp = current->next;
+      delete current;
+      current = tmp;
+    }
+  }
+
+  void Record(Address addr) {
+    EnsureSpaceFor(1);
+    uintptr_t entry = reinterpret_cast<uintptr_t>(addr);
+    DCHECK_GT(entry, static_cast<uintptr_t>(NUMBER_OF_SLOT_TYPES));

[jochen (gone - plz use gerrit), 2016/02/23 13:10:54]

GE would be enough, no?

[ulan, 2016/02/23 13:19:07]

Yes. Done.

+    Insert(entry);
+  }
+
+  void Record(SlotType type, Address addr) {
+    EnsureSpaceFor(2);
+    Insert(static_cast<uintptr_t>(type));
+    uintptr_t entry = reinterpret_cast<uintptr_t>(addr);
+    DCHECK_GT(entry, static_cast<uintptr_t>(NUMBER_OF_SLOT_TYPES));
+    Insert(entry);
+  }
+
+  template <typename UntypedCallback, typename TypedCallback>
+  void Iterate(UntypedCallback untyped_callback, TypedCallback typed_callback) {
+    Node* current = top_;
+    bool typed = false;
+    SlotType type;
+    Address addr;
+    while (current != nullptr) {
+      for (int i = 0; i < current->count; i++) {
+        uintptr_t entry = current->buffer[i];
+        if (entry < NUMBER_OF_SLOT_TYPES) {
+          DCHECK(!typed);
+          typed = true;
+          type = static_cast<SlotType>(entry);
+        } else {
+          addr = reinterpret_cast<Address>(entry);
+          if (typed) {
+            typed_callback(type, addr);
+            typed = false;
+          } else {
+            untyped_callback(addr);
+          }
+        }
+      }
+      current = current->next;
+    }
+  }
+
+ private:
+  void EnsureSpaceFor(int count) {
+    if (top_->remaining_free_slots() < count) top_ = new Node(top_);
+  }
+
+  void Insert(uintptr_t entry) { top_->buffer[top_->count++] = entry; }
+
+  static const int kBufferSize = 16 * KB;
+
+  struct Node : Malloced {
+    explicit Node(Node* next_node) : next(next_node), count(0) {}
+
+    inline int remaining_free_slots() { return kBufferSize - count; }
+
+    Node* next;
+    uintptr_t buffer[kBufferSize];
+    int count;
+  };
+
+  Node* top_;
+};
+
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REMEMBERED_SET_H