Add support for enabling DCHECKs in release mode

src/full-codegen.h

 // Copyright 2012 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_FULL_CODEGEN_H_
 #define V8_FULL_CODEGEN_H_
 
 #include "src/v8.h"
 
 #include "src/allocation.h"
@@ skipping 999 matching lines @@
   static void AddStackCheck(Handle<Code> code, uint32_t pc_offset);
 
   // Revert the patch by AddStackCheck.
   static void RemoveStackCheck(Handle<Code> code, uint32_t pc_offset);
 
   // Return the current patch state of the back edge.
   static BackEdgeState GetBackEdgeState(Isolate* isolate,
                                         Code* unoptimized_code,
                                         Address pc_after);
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
   // Verify that all back edges of a certain loop depth are patched.
   static bool Verify(Isolate* isolate, Code* unoptimized_code);
-#endif  // DEBUG
+#endif  // DCHECK_IS_ON
 
  private:
   Address entry_at(uint32_t index) {
     DCHECK(index < length_);
     return start_ + index * kEntrySize;
   }
 
   static const int kTableLengthSize = kIntSize;
   static const int kAstIdOffset = 0 * kIntSize;
   static const int kPcOffsetOffset = 1 * kIntSize;
   static const int kLoopDepthOffset = 2 * kIntSize;
   static const int kEntrySize = 3 * kIntSize;
 
   Address start_;
   Address instruction_start_;
   uint32_t length_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FULL_CODEGEN_H_