[heap] Make aligned allocations in black areas completely black.

src/heap/spaces-inl.h

 // 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.
 
 #ifndef V8_HEAP_SPACES_INL_H_
 #define V8_HEAP_SPACES_INL_H_
 
 #include "src/heap/incremental-marking.h"
 #include "src/heap/spaces.h"
 #include "src/isolate.h"
@@ skipping 453 matching lines @@
   HeapObject* object = AllocateLinearlyAligned(&allocation_size, alignment);
 
   if (object == NULL) {
     // We don't know exactly how much filler we need to align until space is
     // allocated, so assume the worst case.
     int filler_size = Heap::GetMaximumFillToAlign(alignment);
     allocation_size += filler_size;
     object = free_list_.Allocate(allocation_size);
     if (object == NULL) {
       object = SlowAllocateRaw(allocation_size);
-      if (object != NULL && heap()->incremental_marking()->black_allocation()) {
+    }
+    if (object != NULL) {
+      if (heap()->incremental_marking()->black_allocation()) {
         Address start = object->address();
-        Address end = object->address() + size_in_bytes;
+        Address end = object->address() + allocation_size;
         Page::FromAllocationAreaAddress(start)->CreateBlackArea(start, end);
       }
-    }
-    if (object != NULL && filler_size != 0) {
-      object = heap()->AlignWithFiller(object, size_in_bytes, allocation_size,
-                                       alignment);
-      // Filler objects are initialized, so mark only the aligned object memory
-      // as uninitialized.
-      allocation_size = size_in_bytes;
+      if (filler_size != 0) {
+        object = heap()->AlignWithFiller(object, size_in_bytes, allocation_size,
+                                         alignment);
+        // Filler objects are initialized, so mark only the aligned object
+        // memory as uninitialized.
+        allocation_size = size_in_bytes;
+      }
     }
   }
 
   if (object != NULL) {
     MSAN_ALLOCATED_UNINITIALIZED_MEMORY(object->address(), allocation_size);
     return object;
   }
 
   return AllocationResult::Retry(identity());
 }
@@ skipping 141 matching lines @@
     other->allocation_info_.Reset(nullptr, nullptr);
     return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_SPACES_INL_H_