Add ability to disable inline bump-pointer allocation.

src/spaces.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1765 matching lines @@
     int wasted = free_list_.Free(start, size_in_bytes);
     accounting_stats_.DeallocateBytes(size_in_bytes - wasted);
     return size_in_bytes - wasted;
   }
 
   void ResetFreeList() {
     free_list_.Reset();
   }
 
   // Set space allocation info.
-  void SetTop(Address top, Address limit) {
+  void SetTopAndLimit(Address top, Address limit) {
     ASSERT(top == limit ||
            Page::FromAddress(top) == Page::FromAddress(limit - 1));
     MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
     allocation_info_.set_top(top);
     allocation_info_.set_limit(limit);
   }
 
+  // Empty space allocation info, returning unused area to free list.
+  void EmptyAllocationInfo() {
+    // Mark the old linear allocation area with a free space map so it can be
+    // skipped when scanning the heap.
+    int old_linear_size = static_cast<int>(limit() - top());
+    Free(top(), old_linear_size);
+    SetTopAndLimit(NULL, NULL);
+  }
+
   void Allocate(int bytes) {
     accounting_stats_.AllocateBytes(bytes);
   }
 
   void IncreaseCapacity(int size);
 
   // Releases an unused page and shrinks the space.
   void ReleasePage(Page* page, bool unlink);
 
   // The dummy page that anchors the linked list of pages.
@@ skipping 667 matching lines @@
   // The allocation limit address.
   Address* allocation_limit_address() {
     return allocation_info_.limit_address();
   }
 
   MUST_USE_RESULT INLINE(MaybeObject* AllocateRaw(int size_in_bytes));
 
   // Reset the allocation pointer to the beginning of the active semispace.
   void ResetAllocationInfo();
 
+  void UpdateInlineAllocationLimit(int size_in_bytes);
   void LowerInlineAllocationLimit(intptr_t step) {
     inline_allocation_limit_step_ = step;
-    if (step == 0) {
-      allocation_info_.set_limit(to_space_.page_high());
-    } else {
-      Address new_limit = Min(
-          allocation_info_.top() + inline_allocation_limit_step_,
-          allocation_info_.limit());
-      allocation_info_.set_limit(new_limit);
-    }
+    UpdateInlineAllocationLimit(0);
     top_on_previous_step_ = allocation_info_.top();
   }
 
   // Get the extent of the inactive semispace (for use as a marking stack,
   // or to zap it). Notice: space-addresses are not necessarily on the
   // same page, so FromSpaceStart() might be above FromSpaceEnd().
   Address FromSpacePageLow() { return from_space_.page_low(); }
   Address FromSpacePageHigh() { return from_space_.page_high(); }
   Address FromSpaceStart() { return from_space_.space_start(); }
   Address FromSpaceEnd() { return from_space_.space_end(); }
@@ skipping 419 matching lines @@
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_H_