Add support for enabling DCHECKs in release mode

src/runtime/runtime-strings.cc

 // Copyright 2014 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"
 
 #include "src/arguments.h"
 #include "src/jsregexp-inl.h"
 #include "src/jsregexp.h"
 #include "src/runtime/runtime-utils.h"
@@ skipping 589 matching lines @@
     length += increment;
   }
 
   Handle<SeqTwoByteString> answer;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, answer, isolate->factory()->NewRawTwoByteString(length));
 
   DisallowHeapAllocation no_gc;
 
   uc16* sink = answer->GetChars();
-#ifdef DEBUG
+#if DCHECK_IS_ON
   uc16* end = sink + length;
 #endif
 
   RUNTIME_ASSERT(fixed_array->get(0)->IsString());
   String* first = String::cast(fixed_array->get(0));
   String* separator_raw = *separator;
   int first_length = first->length();
   String::WriteToFlat(first, sink, 0, first_length);
   sink += first_length;
 
@@ skipping 350 matching lines @@
   // further simplified.
   DCHECK(0 < m && m < n);
   // Has high bit set in every w byte less than n.
   uintptr_t tmp1 = kOneInEveryByte * (0x7F + n) - w;
   // Has high bit set in every w byte greater than m.
   uintptr_t tmp2 = w + kOneInEveryByte * (0x7F - m);
   return (tmp1 & tmp2 & (kOneInEveryByte * 0x80));
 }
 
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
 static bool CheckFastAsciiConvert(char* dst, const char* src, int length,
                                   bool changed, bool is_to_lower) {
   bool expected_changed = false;
   for (int i = 0; i < length; i++) {
     if (dst[i] == src[i]) continue;
     expected_changed = true;
     if (is_to_lower) {
       DCHECK('A' <= src[i] && src[i] <= 'Z');
       DCHECK(dst[i] == src[i] + ('a' - 'A'));
     } else {
       DCHECK('a' <= src[i] && src[i] <= 'z');
       DCHECK(dst[i] == src[i] - ('a' - 'A'));
     }
   }
   return (expected_changed == changed);
 }
 #endif
 
 
 template <class Converter>
 static bool FastAsciiConvert(char* dst, const char* src, int length,
                              bool* changed_out) {
-#ifdef DEBUG
+#if DCHECK_IS_ON
   char* saved_dst = dst;
   const char* saved_src = src;
 #endif
   DisallowHeapAllocation no_gc;
   // We rely on the distance between upper and lower case letters
   // being a known power of 2.
   DCHECK('a' - 'A' == (1 << 5));
   // Boundaries for the range of input characters than require conversion.
   static const char lo = Converter::kIsToLower ? 'A' - 1 : 'a' - 1;
   static const char hi = Converter::kIsToLower ? 'Z' + 1 : 'z' + 1;
@@ skipping 281 matching lines @@
   return __RT_impl_Runtime_StringAdd(args, isolate);
 }
 
 
 RUNTIME_FUNCTION(RuntimeReference_IsStringWrapperSafeForDefaultValueOf) {
   UNIMPLEMENTED();
   return NULL;
 }
 }
 }  // namespace v8::internal