Add support for enabling DCHECKs in release mode

src/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_CODEGEN_H_
 #define V8_CODEGEN_H_
 
 #include "src/code-stubs.h"
 #include "src/runtime/runtime.h"
 
@@ skipping 145 matching lines @@
   uint32_t young_sequence_length() const { return young_sequence_.length(); }
   bool IsYoung(byte* candidate) const {
     return memcmp(candidate,
                   young_sequence_.start(),
                   young_sequence_.length()) == 0;
   }
   void CopyYoungSequenceTo(byte* new_buffer) const {
     CopyBytes(new_buffer, young_sequence_.start(), young_sequence_.length());
   }
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
   bool IsOld(byte* candidate) const;
 #endif
 
  protected:
   const EmbeddedVector<byte, kNoCodeAgeSequenceLength> young_sequence_;
 #ifdef DEBUG

[Jakob Kummerow, 2014/12/03 10:53:53]

This is gonna cause arm64 compile errors (cf. codegen-arm64.cc).

 #ifdef V8_TARGET_ARCH_ARM64
   const EmbeddedVector<byte, kNoCodeAgeSequenceLength> old_sequence_;
 #endif
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODEGEN_H_