Improve elements validation and object printing

src/builtins.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/builtins.h"
 
 #include "src/api.h"
 #include "src/api-arguments.h"
 #include "src/api-natives.h"
 #include "src/base/once.h"
@@ skipping 23 matching lines @@
 template <BuiltinExtraArguments extra_args>
 class BuiltinArguments : public Arguments {
  public:
   BuiltinArguments(int length, Object** arguments)
       : Arguments(length, arguments) {
     // Check we have at least the receiver.
     DCHECK_LE(1, this->length());
   }
 
   Object*& operator[] (int index) {
-    DCHECK(index < length());
+    DCHECK_LT(index, length());
     return Arguments::operator[](index);
   }
 
   template <class S> Handle<S> at(int index) {
-    DCHECK(index < length());
+    DCHECK_LT(index, length());
     return Arguments::at<S>(index);
   }
 
   Handle<Object> atOrUndefined(Isolate* isolate, int index) {
     if (index >= length()) {
       return isolate->factory()->undefined_value();
     }
     return at<Object>(index);
   }
 
@@ skipping 4891 matching lines @@
 BUILTIN_LIST_T(DEFINE_BUILTIN_ACCESSOR_T)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 #undef DEFINE_BUILTIN_ACCESSOR_T
 #undef DEFINE_BUILTIN_ACCESSOR_H
 
 }  // namespace internal
 }  // namespace v8