Define DEBUG for v8_optimized_debug=2

src/conversions-inl.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 337 matching lines @@
       }
       ++current;
       if (current == end) break;
     }
 
     if (!allow_trailing_junk &&
         AdvanceToNonspace(unicode_cache, &current, end)) {
       return JunkStringValue();
     }
 
-    ASSERT(buffer_pos < kBufferSize);
+    SLOW_ASSERT(buffer_pos < kBufferSize);
     buffer[buffer_pos] = '\0';
     Vector<const char> buffer_vector(buffer, buffer_pos);
     return negative ? -Strtod(buffer_vector, 0) : Strtod(buffer_vector, 0);
   }
 
   // The following code causes accumulating rounding error for numbers greater
   // than ~2^56. It's explicitly allowed in the spec: "if R is not 2, 4, 8, 10,
   // 16, or 32, then mathInt may be an implementation-dependent approximation to
   // the mathematical integer value" (15.1.2.2).
 
@@ skipping 316 matching lines @@
                                         buffer + buffer_pos,
                                         sign == NEGATIVE,
                                         allow_trailing_junk);
   }
 
   if (nonzero_digit_dropped) {
     buffer[buffer_pos++] = '1';
     exponent--;
   }
 
-  ASSERT(buffer_pos < kBufferSize);
+  SLOW_ASSERT(buffer_pos < kBufferSize);
   buffer[buffer_pos] = '\0';
 
   double converted = Strtod(Vector<const char>(buffer, buffer_pos), exponent);
   return (sign == NEGATIVE) ? -converted : converted;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONVERSIONS_INL_H_