Fix PagedSpace size accounting.

src/spaces.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_SPACES_H_
 #define V8_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/base/platform/mutex.h"
@@ skipping 1439 matching lines @@
   }
 
   // Free allocated bytes, making them available (size -> available).
   void DeallocateBytes(intptr_t size_in_bytes) {
     size_ -= size_in_bytes;
     ASSERT(size_ >= 0);
   }
 
   // Waste free bytes (available -> waste).
   void WasteBytes(int size_in_bytes) {
-    size_ -= size_in_bytes;
+    ASSERT(size_in_bytes >= 0);
     waste_ += size_in_bytes;
-    ASSERT(size_ >= 0);
   }
 
  private:
   intptr_t capacity_;
   intptr_t max_capacity_;
   intptr_t size_;
   intptr_t waste_;
 };
 
 
@@ skipping 377 matching lines @@
   // Allocate the requested number of bytes in the space if possible, return a
   // failure object if not.
   MUST_USE_RESULT inline AllocationResult AllocateRaw(int size_in_bytes);
 
   // Give a block of memory to the space's free list.  It might be added to
   // the free list or accounted as waste.
   // If add_to_freelist is false then just accounting stats are updated and
   // no attempt to add area to free list is made.
   int Free(Address start, int size_in_bytes) {
     int wasted = free_list_.Free(start, size_in_bytes);
-    accounting_stats_.DeallocateBytes(size_in_bytes - wasted);
+    accounting_stats_.DeallocateBytes(size_in_bytes);
+    accounting_stats_.WasteBytes(wasted);
     return size_in_bytes - wasted;
   }
 
   void ResetFreeList() {
     free_list_.Reset();
   }
 
   // Set space allocation info.
   void SetTopAndLimit(Address top, Address limit) {
     ASSERT(top == limit ||
@@ skipping 1155 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_