Add support for enabling DCHECKs in release mode

src/arm/codegen-arm.cc

 // 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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/arm/simulator-arm.h"
 #include "src/codegen.h"
@@ skipping 882 matching lines @@
                       young_sequence_.length() / Assembler::kInstrSize,
                       CodePatcher::DONT_FLUSH));
   PredictableCodeSizeScope scope(patcher->masm(), young_sequence_.length());
   patcher->masm()->PushFixedFrame(r1);
   patcher->masm()->nop(ip.code());
   patcher->masm()->add(
       fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
 }
 
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
 bool CodeAgingHelper::IsOld(byte* candidate) const {
   return Memory::uint32_at(candidate) == kCodeAgePatchFirstInstruction;
 }
 #endif
 
 
 bool Code::IsYoungSequence(Isolate* isolate, byte* sequence) {
   bool result = isolate->code_aging_helper()->IsYoung(sequence);
   DCHECK(result || isolate->code_aging_helper()->IsOld(sequence));
   return result;
@@ skipping 28 matching lines @@
     patcher.masm()->add(r0, pc, Operand(-8));
     patcher.masm()->ldr(pc, MemOperand(pc, -4));
     patcher.masm()->emit_code_stub_address(stub);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM