[heap] Replace page header check in store buffer with slower large object lookup.

Bug: chromium:800251
Change-Id: I44d997bd54be214c34ca2864470f7cdfc3cc30f3
Reviewed-on: https://chromium-review.googlesource.com/859437
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50504}

src/heap/spaces-inl.h

@@ -186,18 +186,13 @@ bool PagedSpace::TryFreeLast(HeapObject* object, int object_size) {
 }
 
 MemoryChunk* MemoryChunk::FromAnyPointerAddress(Heap* heap, Address addr) {
-  MemoryChunk* chunk = MemoryChunk::FromAddress(addr);
-  uintptr_t offset = addr - chunk->address();
-  if (offset < MemoryChunk::kHeaderSize || !chunk->HasPageHeader()) {
-    chunk = heap->lo_space()->FindPageThreadSafe(addr);
+  MemoryChunk* chunk = heap->lo_space()->FindPage(addr);
+  if (chunk == nullptr) {
+    chunk = MemoryChunk::FromAddress(addr);
   }
   return chunk;
 }
 
-Page* Page::FromAnyPointerAddress(Heap* heap, Address addr) {
-  return static_cast<Page*>(MemoryChunk::FromAnyPointerAddress(heap, addr));
-}
-
 void Page::MarkNeverAllocateForTesting() {
   DCHECK(this->owner()->identity() != NEW_SPACE);
   DCHECK(!IsFlagSet(NEVER_ALLOCATE_ON_PAGE));

src/heap/spaces.h

@@ -792,8 +792,6 @@ class Page : public MemoryChunk {
 
   static Page* ConvertNewToOld(Page* old_page);
 
-  inline static Page* FromAnyPointerAddress(Heap* heap, Address addr);
-
   // Create a Page object that is only used as anchor for the doubly-linked
   // list of real pages.
   explicit Page(Space* owner) { InitializeAsAnchor(owner); }
@@ -2944,6 +2942,8 @@ class LargeObjectSpace : public Space {
 
   std::unique_ptr<ObjectIterator> GetObjectIterator() override;
 
+  base::Mutex* chunk_map_mutex() { return &chunk_map_mutex_; }
+
 #ifdef VERIFY_HEAP
   virtual void Verify();
 #endif

src/heap/store-buffer.cc

@@ -105,10 +105,14 @@ void StoreBuffer::MoveEntriesToRememberedSet(int index) {
   DCHECK_GE(index, 0);
   DCHECK_LT(index, kStoreBuffers);
   Address last_inserted_addr = nullptr;
+
+  // We are taking the chunk map mutex here because the page lookup of addr
+  // below may require us to check if addr is part of a large page.
+  base::LockGuard<base::Mutex> guard(heap_->lo_space()->chunk_map_mutex());
   for (Address* current = start_[index]; current < lazy_top_[index];
        current++) {
     Address addr = *current;
-    Page* page = Page::FromAnyPointerAddress(heap_, addr);
+    MemoryChunk* chunk = MemoryChunk::FromAnyPointerAddress(heap_, addr);
     if (IsDeletionAddress(addr)) {
       last_inserted_addr = nullptr;
       current++;
@@ -116,15 +120,15 @@ void StoreBuffer::MoveEntriesToRememberedSet(int index) {
       DCHECK(!IsDeletionAddress(end));
       addr = UnmarkDeletionAddress(addr);
       if (end) {
-        RememberedSet<OLD_TO_NEW>::RemoveRange(page, addr, end,
+        RememberedSet<OLD_TO_NEW>::RemoveRange(chunk, addr, end,
                                                SlotSet::PREFREE_EMPTY_BUCKETS);
       } else {
-        RememberedSet<OLD_TO_NEW>::Remove(page, addr);
+        RememberedSet<OLD_TO_NEW>::Remove(chunk, addr);
       }
     } else {
       DCHECK(!IsDeletionAddress(addr));
       if (addr != last_inserted_addr) {
-        RememberedSet<OLD_TO_NEW>::Insert(page, addr);
+        RememberedSet<OLD_TO_NEW>::Insert(chunk, addr);
         last_inserted_addr = addr;
       }
     }