Fix numerous bugs introduced by reducing Page::kMaxHeapObjectSize.

src/spaces.cc

Index: src/spaces.cc
diff --git a/src/spaces.cc b/src/spaces.cc
index 739154ca55c23474685ad77457b336df08d1e774..e61e7127aa8cee04570f65011b7174893f3a0f03 100644
--- a/src/spaces.cc
+++ b/src/spaces.cc
@@ -1773,7 +1773,23 @@ HeapObject* OldSpace::SlowAllocateRaw(int size_in_bytes) {
         // and allocated object address.
         // Memory above the allocation watermark was not swept and
         // might contain garbage pointers to new space.
-        ASSERT(obj->address() == p->AllocationWatermark());
+        if (obj->address() != p->AllocationWatermark()) {
+          // TODO(gc) this is waste of time. we should enable linear allocation
+          // at least from above watermark
+          HeapObject* filler =
+              HeapObject::FromAddress(p->AllocationWatermark());
+          while (filler->address() < obj->address()) {
+            Address next_filler = filler->address() + filler->Size();
+            if (filler->Size() > ByteArray::kHeaderSize) {
+              for (Address slot = filler->address() + ByteArray::kHeaderSize;
+                   slot < next_filler;
+                   slot += kPointerSize) {
+                Memory::Address_at(slot) = 0;
+              }
+            }
+            filler = HeapObject::FromAddress(next_filler);
+          }
+        }
         p->SetAllocationWatermark(obj->address() + size_in_bytes);
       }
 
@@ -1803,10 +1819,7 @@ void OldSpace::PutRestOfCurrentPageOnFreeList(Page* current_page) {
   current_page->SetAllocationWatermark(allocation_info_.top);
   int free_size =
       static_cast<int>(current_page->ObjectAreaEnd() - allocation_info_.top);
-  if (free_size > 0) {
-    int wasted_bytes = free_list_.Free(allocation_info_.top, free_size);
-    accounting_stats_.WasteBytes(wasted_bytes);
-  }
+  if (free_size > 0) AddToFreeList(allocation_info_.top, free_size);
 }