[heap] Invoke incremental marking step before allocation.

src/heap/spaces.cc

 // Copyright 2011 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/spaces.h"
 
 #include <utility>
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
@@ skipping 2563 matching lines @@
   DCHECK_LT(static_cast<size_t>(owner_->limit() - owner_->top()),
             size_in_bytes);
 
   // Mark the old linear allocation area with a free space map so it can be
   // skipped when scanning the heap.  This also puts it back in the free list
   // if it is big enough.
   owner_->EmptyAllocationInfo();
 
   owner_->heap()->StartIncrementalMarkingIfAllocationLimitIsReached(
       Heap::kNoGCFlags, kNoGCCallbackFlags);
+  // We cannot place incremental marking step in an AllocationObserver because
+  // 1) incremental marking step can change linear allocation area.
+  // 2) allocation observers are called after allocation.
+  // 3) allocation folding assumes that the newly allocated object immediately
+  //    precedes the linear allocation area.
+  // See crbug.com/659165.
+  owner_->heap()
+      ->incremental_marking()
+      ->AdvanceIncrementalMarkingOnAllocation();
 
   size_t new_node_size = 0;
   FreeSpace* new_node = FindNodeFor(size_in_bytes, &new_node_size);
   if (new_node == nullptr) return nullptr;
 
   DCHECK_GE(new_node_size, size_in_bytes);
   size_t bytes_left = new_node_size - size_in_bytes;
 
 #ifdef DEBUG
   for (size_t i = 0; i < size_in_bytes / kPointerSize; i++) {
@@ skipping 409 matching lines @@
   if (Heap::ShouldZapGarbage()) {
     // Make the object consistent so the heap can be verified in OldSpaceStep.
     // We only need to do this in debug builds or if verify_heap is on.
     reinterpret_cast<Object**>(object->address())[0] =
         heap()->fixed_array_map();
     reinterpret_cast<Object**>(object->address())[1] = Smi::kZero;
   }
 
   heap()->StartIncrementalMarkingIfAllocationLimitIsReached(Heap::kNoGCFlags,
                                                             kNoGCCallbackFlags);
+  heap()->incremental_marking()->AdvanceIncrementalMarkingOnAllocation();
+
   AllocationStep(object->address(), object_size);
 
   if (heap()->incremental_marking()->black_allocation()) {
     Marking::MarkBlack(ObjectMarking::MarkBitFrom(object));
     MemoryChunk::IncrementLiveBytesFromGC(object, object_size);
   }
   return object;
 }
 
 
@@ skipping 222 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8