Add support for enabling DCHECKs in release mode

src/heap/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_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
@@ skipping 90 matching lines @@
 class MarkBit {
  public:
   typedef uint32_t CellType;
 
   inline MarkBit(CellType* cell, CellType mask, bool data_only)
       : cell_(cell), mask_(mask), data_only_(data_only) {}
 
   inline CellType* cell() { return cell_; }
   inline CellType mask() { return mask_; }
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
   bool operator==(const MarkBit& other) {
     return cell_ == other.cell_ && mask_ == other.mask_;
   }
 #endif
 
   inline void Set() { *cell_ |= mask_; }
   inline bool Get() { return (*cell_ & mask_) != 0; }
   inline void Clear() { *cell_ &= ~mask_; }
 
   inline bool data_only() { return data_only_; }
@@ skipping 1362 matching lines @@
   void set_end(FreeListNode* end) { end_ = end; }
 
   int* GetAvailableAddress() { return &available_; }
   int available() const { return available_; }
   void set_available(int available) { available_ = available; }
 
   base::Mutex* mutex() { return &mutex_; }
 
   bool IsEmpty() { return top() == 0; }
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
   intptr_t SumFreeList();
   int FreeListLength();
 #endif
 
  private:
   // top_ points to the top FreeListNode* in the free list category.
   base::AtomicWord top_;
   FreeListNode* end_;
   base::Mutex mutex_;
 
@@ skipping 67 matching lines @@
   // is unitialized.  A failure is returned if no block is available.  The
   // number of bytes lost to fragmentation is returned in the output parameter
   // 'wasted_bytes'.  The size should be a non-zero multiple of the word size.
   MUST_USE_RESULT HeapObject* Allocate(int size_in_bytes);
 
   bool IsEmpty() {
     return small_list_.IsEmpty() && medium_list_.IsEmpty() &&
            large_list_.IsEmpty() && huge_list_.IsEmpty();
   }
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
   void Zap();
   intptr_t SumFreeLists();
   bool IsVeryLong();
 #endif
 
   // Used after booting the VM.
   void RepairLists(Heap* heap);
 
   intptr_t EvictFreeListItems(Page* p);
   bool ContainsPageFreeListItems(Page* p);
@@ skipping 1324 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_SPACES_H_