Cleaned up runtime macros a bit.

src/runtime.cc

 // Copyright 2012 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 51 matching lines @@
 namespace v8 {
 namespace internal {
 
 
 #define RUNTIME_ASSERT(value) \
   if (!(value)) return isolate->ThrowIllegalOperation();
 
 // Cast the given object to a value of the specified type and store
 // it in a variable with the given name.  If the object is not of the
 // expected type call IllegalOperation and return.
-#define CONVERT_CHECKED(Type, name, obj)                             \
-  RUNTIME_ASSERT(obj->Is##Type());                                   \
-  Type* name = Type::cast(obj);
+#define CONVERT_CHECKED(Type, name, index)                           \

[Jakob Kummerow, 2012/02/20 17:31:47]

Now that there's so little difference between CONVERT_CHECKED and
CONVERT_ARG_CHECKED (and you wouldn't guess *what* the difference is from the
macros' names!), have you thought about (1) merging or (2) renaming them?

(1) would effectively mean to handlify most of this file.

A suggestion for (2) would be:
CONVERT_CHECKED -> CONVERT_ARG_CHECKED
CONVERT_ARG_CHECKED -> CONVERT_ARG_HANDLE_CHECKED

[Sven Panne, 2012/02/21 07:21:01]

I am not 100% sure if we can really handlify everything here (probably yes, but
we need e.g. Object::IsObject, too, which shouldn't be too hard to implement
;-), so I left both macros. Merging them can be done in a separate CL, so I'll
follow your renaming proposal for now.

+  RUNTIME_ASSERT(args[index]->Is##Type());                           \
+  Type* name = Type::cast(args[index]);
 
 #define CONVERT_ARG_CHECKED(Type, name, index)                       \
   RUNTIME_ASSERT(args[index]->Is##Type());                           \
   Handle<Type> name = args.at<Type>(index);
 
 // Cast the given object to a boolean and store it in a variable with
 // the given name.  If the object is not a boolean call IllegalOperation
 // and return.
-#define CONVERT_BOOLEAN_CHECKED(name, obj)                            \
-  RUNTIME_ASSERT(obj->IsBoolean());                                   \
-  bool name = (obj)->IsTrue();
+#define CONVERT_BOOLEAN_CHECKED(name, index)                         \
+  RUNTIME_ASSERT(args[index]->IsBoolean());                          \
+  bool name = args[index]->IsTrue();
 
 // Cast the given argument to a Smi and store its value in an int variable
 // with the given name.  If the argument is not a Smi call IllegalOperation
 // and return.
 #define CONVERT_SMI_ARG_CHECKED(name, index)                         \
   RUNTIME_ASSERT(args[index]->IsSmi());                              \
   int name = args.smi_at(index);
 
 // Cast the given argument to a double and store it in a variable with
 // the given name.  If the argument is not a number (as opposed to
 // the number not-a-number) call IllegalOperation and return.
 #define CONVERT_DOUBLE_ARG_CHECKED(name, index)                      \
   RUNTIME_ASSERT(args[index]->IsNumber());                           \
   double name = args.number_at(index);
 
 // Call the specified converter on the object *comand store the result in
 // a variable of the specified type with the given name.  If the
 // object is not a Number call IllegalOperation and return.
 #define CONVERT_NUMBER_CHECKED(type, name, Type, obj)                \
   RUNTIME_ASSERT(obj->IsNumber());                                   \
   type name = NumberTo##Type(obj);
 
 
+// Cast the given argument to PropertyDetails and store its value in a
+// variable with the given name.  If the argument is not a Smi call
+// IllegalOperation and return.
+#define CONVERT_PROPERTY_DETAILS_CHECKED(name, index)                \
+  RUNTIME_ASSERT(args[index]->IsSmi());                              \
+  PropertyDetails name = PropertyDetails(Smi::cast(args[index]));
+
+
 // Assert that the given argument has a valid value for a StrictModeFlag
 // and store it in a StrictModeFlag variable with the given name.
 #define CONVERT_STRICT_MODE_ARG(name, index)                         \
-  ASSERT(args[index]->IsSmi());                                      \
-  ASSERT(args.smi_at(index) == kStrictMode ||                        \
-         args.smi_at(index) == kNonStrictMode);                      \
+  RUNTIME_ASSERT(args[index]->IsSmi());                              \
+  RUNTIME_ASSERT(args.smi_at(index) == kStrictMode ||                \
+                 args.smi_at(index) == kNonStrictMode);              \
   StrictModeFlag name =                                              \
       static_cast<StrictModeFlag>(args.smi_at(index));
 
 
 // Assert that the given argument has a valid value for a LanguageMode
 // and store it in a LanguageMode variable with the given name.
 #define CONVERT_LANGUAGE_MODE_ARG(name, index)                       \
   ASSERT(args[index]->IsSmi());                                      \

[Jakob Kummerow, 2012/02/20 17:31:47]

RUNTIME_ASSERT here, too?

[Sven Panne, 2012/02/21 07:21:01]

This is what initially thought, too, but the functions using it have a return
type of ObjectPair, so it won't work. ObjectPair itself looks quite scary, and
I'm sure there's a nicer way without it, but I wasn't brave enough to touch that
voodoo magic...

   ASSERT(args.smi_at(index) == CLASSIC_MODE ||                       \
          args.smi_at(index) == STRICT_MODE ||                        \
          args.smi_at(index) == EXTENDED_MODE);                       \
   LanguageMode name =                                                \
       static_cast<LanguageMode>(args.smi_at(index));
 
 
 MUST_USE_RESULT static MaybeObject* DeepCopyBoilerplate(Isolate* isolate,
                                                    JSObject* boilerplate) {
   StackLimitCheck check(isolate);
@@ skipping 551 matching lines @@
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsJSFunctionProxy) {
   ASSERT(args.length() == 1);
   Object* obj = args[0];
   return isolate->heap()->ToBoolean(obj->IsJSFunctionProxy());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetHandler) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSProxy, proxy, args[0]);
+  CONVERT_CHECKED(JSProxy, proxy, 0);
   return proxy->handler();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetCallTrap) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSFunctionProxy, proxy, args[0]);
+  CONVERT_CHECKED(JSFunctionProxy, proxy, 0);
   return proxy->call_trap();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetConstructTrap) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSFunctionProxy, proxy, args[0]);
+  CONVERT_CHECKED(JSFunctionProxy, proxy, 0);
   return proxy->construct_trap();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Fix) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSProxy, proxy, args[0]);
+  CONVERT_CHECKED(JSProxy, proxy, 0);
   proxy->Fix();
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetInitialize) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSSet, holder, 0);
   Handle<ObjectHashSet> table = isolate->factory()->NewObjectHashSet(0);
@@ skipping 107 matching lines @@
   ASSERT(args.length() == 1);
   Object* obj = args[0];
   if (!obj->IsJSObject()) return isolate->heap()->null_value();
   return JSObject::cast(obj)->class_name();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetPrototype) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSReceiver, input_obj, args[0]);
+  CONVERT_CHECKED(JSReceiver, input_obj, 0);
   Object* obj = input_obj;
   // We don't expect access checks to be needed on JSProxy objects.
   ASSERT(!obj->IsAccessCheckNeeded() || obj->IsJSObject());
   do {
     if (obj->IsAccessCheckNeeded() &&
         !isolate->MayNamedAccess(JSObject::cast(obj),
                                  isolate->heap()->Proto_symbol(),
                                  v8::ACCESS_GET)) {
       isolate->ReportFailedAccessCheck(JSObject::cast(obj), v8::ACCESS_GET);
       return isolate->heap()->undefined_value();
@@ skipping 286 matching lines @@
     }
     elms->set(VALUE_INDEX, value);
   }
 
   return *desc;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PreventExtensions) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSObject, obj, args[0]);
+  CONVERT_CHECKED(JSObject, obj, 0);
   return obj->PreventExtensions();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsExtensible) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSObject, obj, args[0]);
+  CONVERT_CHECKED(JSObject, obj, 0);
   if (obj->IsJSGlobalProxy()) {
     Object* proto = obj->GetPrototype();
     if (proto->IsNull()) return isolate->heap()->false_value();
     ASSERT(proto->IsJSGlobalObject());
     obj = JSObject::cast(proto);
   }
   return isolate->heap()->ToBoolean(obj->map()->is_extensible());
 }
 
 
@@ skipping 20 matching lines @@
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsTemplate) {
   ASSERT(args.length() == 1);
   Object* arg = args[0];
   bool result = arg->IsObjectTemplateInfo() || arg->IsFunctionTemplateInfo();
   return isolate->heap()->ToBoolean(result);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetTemplateField) {
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(HeapObject, templ, args[0]);
-  CONVERT_CHECKED(Smi, field, args[1]);
-  int index = field->value();
+  CONVERT_CHECKED(HeapObject, templ, 0);
+  CONVERT_SMI_ARG_CHECKED(index, 1)
   int offset = index * kPointerSize + HeapObject::kHeaderSize;
   InstanceType type = templ->map()->instance_type();
   RUNTIME_ASSERT(type ==  FUNCTION_TEMPLATE_INFO_TYPE ||
                  type ==  OBJECT_TEMPLATE_INFO_TYPE);
   RUNTIME_ASSERT(offset > 0);
   if (type == FUNCTION_TEMPLATE_INFO_TYPE) {
     RUNTIME_ASSERT(offset < FunctionTemplateInfo::kSize);
   } else {
     RUNTIME_ASSERT(offset < ObjectTemplateInfo::kSize);
   }
   return *HeapObject::RawField(templ, offset);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DisableAccessChecks) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(HeapObject, object, args[0]);
+  CONVERT_CHECKED(HeapObject, object, 0);
   Map* old_map = object->map();
   bool needs_access_checks = old_map->is_access_check_needed();
   if (needs_access_checks) {
     // Copy map so it won't interfere constructor's initial map.
     Object* new_map;
     { MaybeObject* maybe_new_map = old_map->CopyDropTransitions();
       if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
     }
 
     Map::cast(new_map)->set_is_access_check_needed(false);
     object->set_map(Map::cast(new_map));
   }
   return isolate->heap()->ToBoolean(needs_access_checks);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_EnableAccessChecks) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(HeapObject, object, args[0]);
+  CONVERT_CHECKED(HeapObject, object, 0);
   Map* old_map = object->map();
   if (!old_map->is_access_check_needed()) {
     // Copy map so it won't interfere constructor's initial map.
     Object* new_map;
     { MaybeObject* maybe_new_map = old_map->CopyDropTransitions();
       if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
     }
 
     Map::cast(new_map)->set_is_access_check_needed(true);
     object->set_map(Map::cast(new_map));
@@ skipping 515 matching lines @@
   // Write in-object properties after the length of the array.
   array->InObjectPropertyAtPut(JSRegExpResult::kIndexIndex, args[1]);
   array->InObjectPropertyAtPut(JSRegExpResult::kInputIndex, args[2]);
   return array;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpInitializeObject) {
   AssertNoAllocation no_alloc;
   ASSERT(args.length() == 5);
-  CONVERT_CHECKED(JSRegExp, regexp, args[0]);
-  CONVERT_CHECKED(String, source, args[1]);
+  CONVERT_CHECKED(JSRegExp, regexp, 0);
+  CONVERT_CHECKED(String, source, 1);
 
   Object* global = args[2];
   if (!global->IsTrue()) global = isolate->heap()->false_value();
 
   Object* ignoreCase = args[3];
   if (!ignoreCase->IsTrue()) ignoreCase = isolate->heap()->false_value();
 
   Object* multiline = args[4];
   if (!multiline->IsTrue()) multiline = isolate->heap()->false_value();
 
@@ skipping 92 matching lines @@
   InstallBuiltin(isolate, holder, "slice", Builtins::kArraySlice);
   InstallBuiltin(isolate, holder, "splice", Builtins::kArraySplice);
   InstallBuiltin(isolate, holder, "concat", Builtins::kArrayConcat);
 
   return *holder;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetDefaultReceiver) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSReceiver, callable, args[0]);
+  CONVERT_CHECKED(JSReceiver, callable, 0);
 
   if (!callable->IsJSFunction()) {
     HandleScope scope(isolate);
     bool threw = false;
     Handle<Object> delegate =
         Execution::TryGetFunctionDelegate(Handle<JSReceiver>(callable), &threw);
     if (threw) return Failure::Exception();
     callable = JSFunction::cast(*delegate);
   }
   JSFunction* function = JSFunction::cast(callable);
@@ skipping 38 matching lines @@
   }
   literals->set(index, *regexp);
   return *regexp;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetName) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, f, args[0]);
+  CONVERT_CHECKED(JSFunction, f, 0);
   return f->shared()->name();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetName) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(JSFunction, f, args[0]);
-  CONVERT_CHECKED(String, name, args[1]);
+  CONVERT_CHECKED(JSFunction, f, 0);
+  CONVERT_CHECKED(String, name, 1);
   f->shared()->set_name(name);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionNameShouldPrintAsAnonymous) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSFunction, f, args[0]);
+  CONVERT_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(
       f->shared()->name_should_print_as_anonymous());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionMarkNameShouldPrintAsAnonymous) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSFunction, f, args[0]);
+  CONVERT_CHECKED(JSFunction, f, 0);
   f->shared()->set_name_should_print_as_anonymous(true);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionRemovePrototype) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, f, args[0]);
+  CONVERT_CHECKED(JSFunction, f, 0);
   Object* obj = f->RemovePrototype();
   if (obj->IsFailure()) return obj;
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetScript) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, fun, args[0]);
+  CONVERT_CHECKED(JSFunction, fun, 0);
   Handle<Object> script = Handle<Object>(fun->shared()->script(), isolate);
   if (!script->IsScript()) return isolate->heap()->undefined_value();
 
   return *GetScriptWrapper(Handle<Script>::cast(script));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetSourceCode) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   Handle<SharedFunctionInfo> shared(f->shared());
   return *shared->GetSourceCode();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetScriptSourcePosition) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, fun, args[0]);
+  CONVERT_CHECKED(JSFunction, fun, 0);
   int pos = fun->shared()->start_position();
   return Smi::FromInt(pos);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetPositionForOffset) {
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(Code, code, args[0]);
+  CONVERT_CHECKED(Code, code, 0);
   CONVERT_NUMBER_CHECKED(int, offset, Int32, args[1]);
 
   RUNTIME_ASSERT(0 <= offset && offset < code->Size());
 
   Address pc = code->address() + offset;
   return Smi::FromInt(code->SourcePosition(pc));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetInstanceClassName) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(JSFunction, fun, args[0]);
-  CONVERT_CHECKED(String, name, args[1]);
+  CONVERT_CHECKED(JSFunction, fun, 0);
+  CONVERT_CHECKED(String, name, 1);
   fun->SetInstanceClassName(name);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetLength) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(JSFunction, fun, args[0]);
-  CONVERT_CHECKED(Smi, length, args[1]);
-  fun->shared()->set_length(length->value());
-  return length;
+  CONVERT_CHECKED(JSFunction, fun, 0);
+  CONVERT_SMI_ARG_CHECKED(length, 1);
+  fun->shared()->set_length(length);
+  return fun;

[Jakob Kummerow, 2012/02/20 17:31:47]

Is this change intentional?

[Sven Panne, 2012/02/21 07:21:01]

Yep, it is just our usual ultra-confusing way of signaling "OK". Thinking about
it, I'll replace it with undefined to make it a bit clearer.

 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetPrototype) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(JSFunction, fun, args[0]);
+  CONVERT_CHECKED(JSFunction, fun, 0);
   ASSERT(fun->should_have_prototype());
   Object* obj;
   { MaybeObject* maybe_obj =
         Accessors::FunctionSetPrototype(fun, args[1], NULL);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   return args[0];  // return TOS
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetReadOnlyPrototype) {
   NoHandleAllocation ha;
   RUNTIME_ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSFunction, function, args[0]);
+  CONVERT_CHECKED(JSFunction, function, 0);
 
   MaybeObject* maybe_name =
       isolate->heap()->AllocateStringFromAscii(CStrVector("prototype"));
   String* name;
   if (!maybe_name->To(&name)) return maybe_name;
 
   if (function->HasFastProperties()) {
     // Construct a new field descriptor with updated attributes.
     DescriptorArray* instance_desc = function->map()->instance_descriptors();
     int index = instance_desc->Search(name);
@@ skipping 35 matching lines @@
     function->property_dictionary()->DetailsAtPut(entry, new_details);
   }
   return function;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionIsAPIFunction) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, f, args[0]);
+  CONVERT_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(f->shared()->IsApiFunction());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionIsBuiltin) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, f, args[0]);
+  CONVERT_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(f->IsBuiltin());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetCode) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(JSFunction, target, 0);
   Handle<Object> code = args.at<Object>(1);
@@ skipping 76 matching lines @@
     }
   }
   return isolate->heap()->empty_string();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringCharCodeAt) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(String, subject, args[0]);
+  CONVERT_CHECKED(String, subject, 0);
   Object* index = args[1];
   RUNTIME_ASSERT(index->IsNumber());
 
   uint32_t i = 0;
   if (index->IsSmi()) {
     int value = Smi::cast(index)->value();
     if (value < 0) return isolate->heap()->nan_value();
     i = value;
   } else {
     ASSERT(index->IsHeapNumber());
@@ skipping 956 matching lines @@
     MemoryChunk::IncrementLiveBytesFromMutator(answer->address(), -delta);
   }
 
   return *answer;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringReplaceRegExpWithString) {
   ASSERT(args.length() == 4);
 
-  CONVERT_CHECKED(String, subject, args[0]);
+  CONVERT_CHECKED(String, subject, 0);
   if (!subject->IsFlat()) {
     Object* flat_subject;
     { MaybeObject* maybe_flat_subject = subject->TryFlatten();
       if (!maybe_flat_subject->ToObject(&flat_subject)) {
         return maybe_flat_subject;
       }
     }
     subject = String::cast(flat_subject);
   }
 
-  CONVERT_CHECKED(String, replacement, args[2]);
+  CONVERT_CHECKED(String, replacement, 2);
   if (!replacement->IsFlat()) {
     Object* flat_replacement;
     { MaybeObject* maybe_flat_replacement = replacement->TryFlatten();
       if (!maybe_flat_replacement->ToObject(&flat_replacement)) {
         return maybe_flat_replacement;
       }
     }
     replacement = String::cast(flat_replacement);
   }
 
-  CONVERT_CHECKED(JSRegExp, regexp, args[1]);
-  CONVERT_CHECKED(JSArray, last_match_info, args[3]);
+  CONVERT_CHECKED(JSRegExp, regexp, 1);
+  CONVERT_CHECKED(JSArray, last_match_info, 3);
 
   ASSERT(last_match_info->HasFastElements());
 
   if (replacement->length() == 0) {
     if (subject->HasOnlyAsciiChars()) {
       return StringReplaceRegExpWithEmptyString<SeqAsciiString>(
           isolate, subject, regexp, last_match_info);
     } else {
       return StringReplaceRegExpWithEmptyString<SeqTwoByteString>(
           isolate, subject, regexp, last_match_info);
@@ skipping 241 matching lines @@
   }
 
   return Smi::FromInt(position);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringLocaleCompare) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(String, str1, args[0]);
-  CONVERT_CHECKED(String, str2, args[1]);
+  CONVERT_CHECKED(String, str1, 0);
+  CONVERT_CHECKED(String, str2, 1);
 
   if (str1 == str2) return Smi::FromInt(0);  // Equal.
   int str1_length = str1->length();
   int str2_length = str2->length();
 
   // Decide trivial cases without flattening.
   if (str1_length == 0) {
     if (str2_length == 0) return Smi::FromInt(0);  // Equal.
     return Smi::FromInt(-str2_length);
   } else {
@@ skipping 26 matching lines @@
   }
 
   return Smi::FromInt(str1_length - str2_length);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SubString) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 3);
 
-  CONVERT_CHECKED(String, value, args[0]);
+  CONVERT_CHECKED(String, value, 0);
   int start, end;
   // We have a fast integer-only case here to avoid a conversion to double in
   // the common case where from and to are Smis.
   if (args[1]->IsSmi() && args[2]->IsSmi()) {
     CONVERT_SMI_ARG_CHECKED(from_number, 1);
     CONVERT_SMI_ARG_CHECKED(to_number, 2);
     start = from_number;
     end = to_number;
   } else {
     CONVERT_DOUBLE_ARG_CHECKED(from_number, 1);
@@ skipping 752 matching lines @@
 // Implements part of 8.12.9 DefineOwnProperty.
 // There are 3 cases that lead here:
 // Step 4b - define a new accessor property.
 // Steps 9c & 12 - replace an existing data property with an accessor property.
 // Step 12 - update an existing accessor property with an accessor or generic
 //           descriptor.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DefineOrRedefineAccessorProperty) {
   ASSERT(args.length() == 5);
   HandleScope scope(isolate);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
-  CONVERT_CHECKED(String, name, args[1]);
-  CONVERT_CHECKED(Smi, flag_setter, args[2]);
+  CONVERT_CHECKED(String, name, 1);
+  CONVERT_SMI_ARG_CHECKED(flag_setter, 2);
   Object* fun = args[3];
-  CONVERT_CHECKED(Smi, flag_attr, args[4]);
+  CONVERT_SMI_ARG_CHECKED(unchecked, 4);
 
-  int unchecked = flag_attr->value();
   RUNTIME_ASSERT((unchecked & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
   PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
 
   RUNTIME_ASSERT(!obj->IsNull());
   RUNTIME_ASSERT(fun->IsSpecFunction() || fun->IsUndefined());
-  return obj->DefineAccessor(name, flag_setter->value() == 0, fun, attr);
+  return obj->DefineAccessor(name, flag_setter == 0, fun, attr);
 }
 
 // Implements part of 8.12.9 DefineOwnProperty.
 // There are 3 cases that lead here:
 // Step 4a - define a new data property.
 // Steps 9b & 12 - replace an existing accessor property with a data property.
 // Step 12 - update an existing data property with a data or generic
 //           descriptor.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DefineOrRedefineDataProperty) {
   ASSERT(args.length() == 4);
   HandleScope scope(isolate);
   CONVERT_ARG_CHECKED(JSObject, js_object, 0);
   CONVERT_ARG_CHECKED(String, name, 1);
   Handle<Object> obj_value = args.at<Object>(2);
-  CONVERT_CHECKED(Smi, flag, args[3]);
+  CONVERT_SMI_ARG_CHECKED(unchecked, 3);
 
-  int unchecked = flag->value();
   RUNTIME_ASSERT((unchecked & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
   PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
 
   // Check if this is an element.
   uint32_t index;
   bool is_element = name->AsArrayIndex(&index);
 
   // Special case for elements if any of the flags might be involved.
   // If elements are in fast case we always implicitly assume that:
   // DONT_DELETE: false, DONT_ENUM: false, READ_ONLY: false.
@@ skipping 391 matching lines @@
   }
   return *object;
 }
 
 
 // Set a local property, even if it is READ_ONLY.  If the property does not
 // exist, it will be added with attributes NONE.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IgnoreAttributesAndSetProperty) {
   NoHandleAllocation ha;
   RUNTIME_ASSERT(args.length() == 3 || args.length() == 4);
-  CONVERT_CHECKED(JSObject, object, args[0]);
-  CONVERT_CHECKED(String, name, args[1]);
+  CONVERT_CHECKED(JSObject, object, 0);
+  CONVERT_CHECKED(String, name, 1);
   // Compute attributes.
   PropertyAttributes attributes = NONE;
   if (args.length() == 4) {
-    CONVERT_CHECKED(Smi, value_obj, args[3]);
-    int unchecked_value = value_obj->value();
+    CONVERT_SMI_ARG_CHECKED(unchecked_value, 3);
     // Only attribute bits should be set.
     RUNTIME_ASSERT(
         (unchecked_value & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
     attributes = static_cast<PropertyAttributes>(unchecked_value);
   }
 
   return object->
       SetLocalPropertyIgnoreAttributes(name, args[2], attributes);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DeleteProperty) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 3);
 
-  CONVERT_CHECKED(JSReceiver, object, args[0]);
-  CONVERT_CHECKED(String, key, args[1]);
+  CONVERT_CHECKED(JSReceiver, object, 0);
+  CONVERT_CHECKED(String, key, 1);
   CONVERT_STRICT_MODE_ARG(strict_mode, 2);
   return object->DeleteProperty(key, (strict_mode == kStrictMode)
                                       ? JSReceiver::STRICT_DELETION
                                       : JSReceiver::NORMAL_DELETION);
 }
 
 
 static Object* HasLocalPropertyImplementation(Isolate* isolate,
                                               Handle<JSObject> object,
                                               Handle<String> key) {
   if (object->HasLocalProperty(*key)) return isolate->heap()->true_value();
   // Handle hidden prototypes.  If there's a hidden prototype above this thing
   // then we have to check it for properties, because they are supposed to
   // look like they are on this object.
   Handle<Object> proto(object->GetPrototype());
   if (proto->IsJSObject() &&
       Handle<JSObject>::cast(proto)->map()->is_hidden_prototype()) {
     return HasLocalPropertyImplementation(isolate,
                                           Handle<JSObject>::cast(proto),
                                           key);
   }
   return isolate->heap()->false_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HasLocalProperty) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(String, key, args[1]);
+  CONVERT_CHECKED(String, key, 1);
 
   uint32_t index;
   const bool key_is_array_index = key->AsArrayIndex(&index);
 
   Object* obj = args[0];
   // Only JS objects can have properties.
   if (obj->IsJSObject()) {
     JSObject* object = JSObject::cast(obj);
     // Fast case: either the key is a real named property or it is not
     // an array index and there are no interceptors or hidden
@@ skipping 17 matching lines @@
       return isolate->heap()->true_value();
     }
   }
   return isolate->heap()->false_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HasProperty) {
   NoHandleAllocation na;
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(JSReceiver, receiver, args[0]);
-  CONVERT_CHECKED(String, key, args[1]);
+  CONVERT_CHECKED(JSReceiver, receiver, 0);
+  CONVERT_CHECKED(String, key, 1);
 
   bool result = receiver->HasProperty(key);
   if (isolate->has_pending_exception()) return Failure::Exception();
   return isolate->heap()->ToBoolean(result);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HasElement) {
   NoHandleAllocation na;
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(JSReceiver, receiver, args[0]);
-  CONVERT_CHECKED(Smi, index, args[1]);
+  CONVERT_CHECKED(JSReceiver, receiver, 0);
+  CONVERT_SMI_ARG_CHECKED(index, 1);
 
-  bool result = receiver->HasElement(index->value());
+  bool result = receiver->HasElement(index);
   if (isolate->has_pending_exception()) return Failure::Exception();
   return isolate->heap()->ToBoolean(result);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsPropertyEnumerable) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(JSObject, object, args[0]);
-  CONVERT_CHECKED(String, key, args[1]);
+  CONVERT_CHECKED(JSObject, object, 0);
+  CONVERT_CHECKED(String, key, 1);
 
   uint32_t index;
   if (key->AsArrayIndex(&index)) {
     JSObject::LocalElementType type = object->HasLocalElement(index);
     switch (type) {
       case JSObject::UNDEFINED_ELEMENT:
       case JSObject::STRING_CHARACTER_ELEMENT:
         return isolate->heap()->false_value();
       case JSObject::INTERCEPTED_ELEMENT:
       case JSObject::FAST_ELEMENT:
@@ skipping 40 matching lines @@
 
 
 // Returns either a FixedArray as Runtime_GetPropertyNames,
 // or, if the given object has an enum cache that contains
 // all enumerable properties of the object and its prototypes
 // have none, the map of the object. This is used to speed up
 // the check for deletions during a for-in.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetPropertyNamesFast) {
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSReceiver, raw_object, args[0]);
+  CONVERT_CHECKED(JSReceiver, raw_object, 0);
 
   if (raw_object->IsSimpleEnum()) return raw_object->map();
 
   HandleScope scope(isolate);
   Handle<JSReceiver> object(raw_object);
   bool threw = false;
   Handle<FixedArray> content =
       GetKeysInFixedArrayFor(object, INCLUDE_PROTOS, &threw);
   if (threw) return Failure::Exception();
 
@@ skipping 166 matching lines @@
   if (obj->HasIndexedInterceptor()) {
     v8::Handle<v8::Array> result = GetKeysForIndexedInterceptor(obj, obj);
     if (!result.IsEmpty()) return *v8::Utils::OpenHandle(*result);
   }
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LocalKeys) {
   ASSERT_EQ(args.length(), 1);
-  CONVERT_CHECKED(JSObject, raw_object, args[0]);
+  CONVERT_CHECKED(JSObject, raw_object, 0);
   HandleScope scope(isolate);
   Handle<JSObject> object(raw_object);
 
   if (object->IsJSGlobalProxy()) {
     // Do access checks before going to the global object.
     if (object->IsAccessCheckNeeded() &&
         !isolate->MayNamedAccess(*object, isolate->heap()->undefined_value(),
                              v8::ACCESS_KEYS)) {
       isolate->ReportFailedAccessCheck(*object, v8::ACCESS_KEYS);
       return *isolate->factory()->NewJSArray(0);
@@ skipping 171 matching lines @@
     d = 10 * d + (s[i] - '0');
   }
 
   return d;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringToNumber) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(String, subject, args[0]);
+  CONVERT_CHECKED(String, subject, 0);
   subject->TryFlatten();
 
   // Fast case: short integer or some sorts of junk values.
   int len = subject->length();
   if (subject->IsSeqAsciiString()) {
     if (len == 0) return Smi::FromInt(0);
 
     char const* data = SeqAsciiString::cast(subject)->GetChars();
     bool minus = (data[0] == '-');
     int start_pos = (minus ? 1 : 0);
@@ skipping 35 matching lines @@
   // Slower case.
   return isolate->heap()->NumberFromDouble(
       StringToDouble(isolate->unicode_cache(), subject, ALLOW_HEX));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringFromCharCodeArray) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSArray, codes, args[0]);
+  CONVERT_CHECKED(JSArray, codes, 0);
   int length = Smi::cast(codes->length())->value();
 
   // Check if the string can be ASCII.
   int i;
   for (i = 0; i < length; i++) {
     Object* element;
     { MaybeObject* maybe_element = codes->GetElement(i);
       // We probably can't get an exception here, but just in order to enforce
       // the checking of inputs in the runtime calls we check here.
       if (!maybe_element->ToObject(&element)) return maybe_element;
@@ skipping 59 matching lines @@
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
   };
   return kNotEscaped[character] != 0;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_URIEscape) {
   const char hex_chars[] = "0123456789ABCDEF";
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(String, source, args[0]);
+  CONVERT_CHECKED(String, source, 0);
 
   source->TryFlatten();
 
   int escaped_length = 0;
   int length = source->length();
   {
     Access<StringInputBuffer> buffer(
         isolate->runtime_state()->string_input_buffer());
     buffer->Reset(source);
     while (buffer->has_more()) {
@@ skipping 97 matching lines @@
   } else {
     *step = 1;
     return character;
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_URIUnescape) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(String, source, args[0]);
+  CONVERT_CHECKED(String, source, 0);
 
   source->TryFlatten();
 
   bool ascii = true;
   int length = source->length();
 
   int unescaped_length = 0;
   for (int i = 0; i < length; unescaped_length++) {
     int step;
     if (Unescape(source, i, length, &step) > String::kMaxAsciiCharCode) {
@@ skipping 236 matching lines @@
           new_string->address() + SeqString::kHeaderSize));
   isolate->heap()->new_space()->
       template ShrinkStringAtAllocationBoundary<StringType>(
           new_string, final_length);
   return new_string;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_QuoteJSONString) {
   NoHandleAllocation ha;
-  CONVERT_CHECKED(String, str, args[0]);
+  CONVERT_CHECKED(String, str, 0);
   if (!str->IsFlat()) {
     MaybeObject* try_flatten = str->TryFlatten();
     Object* flat;
     if (!try_flatten->ToObject(&flat)) {
       return try_flatten;
     }
     str = String::cast(flat);
     ASSERT(str->IsFlat());
   }
   String::FlatContent flat = str->GetFlatContent();
   ASSERT(flat.IsFlat());
   if (flat.IsTwoByte()) {
     return QuoteJsonString<uc16, SeqTwoByteString, false>(isolate,
                                                           flat.ToUC16Vector());
   } else {
     return QuoteJsonString<char, SeqAsciiString, false>(isolate,
                                                         flat.ToAsciiVector());
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_QuoteJSONStringComma) {
   NoHandleAllocation ha;
-  CONVERT_CHECKED(String, str, args[0]);
+  CONVERT_CHECKED(String, str, 0);
   if (!str->IsFlat()) {
     MaybeObject* try_flatten = str->TryFlatten();
     Object* flat;
     if (!try_flatten->ToObject(&flat)) {
       return try_flatten;
     }
     str = String::cast(flat);
     ASSERT(str->IsFlat());
   }
   String::FlatContent flat = str->GetFlatContent();
@@ skipping 56 matching lines @@
   isolate->heap()->new_space()->
       template ShrinkStringAtAllocationBoundary<StringType>(
           new_string, final_length);
   return new_string;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_QuoteJSONStringArray) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSArray, array, args[0]);
+  CONVERT_CHECKED(JSArray, array, 0);
 
   if (!array->HasFastElements()) return isolate->heap()->undefined_value();
   FixedArray* elements = FixedArray::cast(array->elements());
   int n = elements->length();
   bool ascii = true;
   int total_length = 0;
 
   for (int i = 0; i < n; i++) {
     Object* elt = elements->get(i);
     if (!elt->IsString()) return isolate->heap()->undefined_value();
@@ skipping 21 matching lines @@
     return QuoteJsonStringArray<uc16, SeqTwoByteString>(isolate,
                                                         elements,
                                                         worst_case_length);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringParseInt) {
   NoHandleAllocation ha;
 
-  CONVERT_CHECKED(String, s, args[0]);
+  CONVERT_CHECKED(String, s, 0);
   CONVERT_SMI_ARG_CHECKED(radix, 1);
 
   s->TryFlatten();
 
   RUNTIME_ASSERT(radix == 0 || (2 <= radix && radix <= 36));
   double value = StringToInt(isolate->unicode_cache(), s, radix);
   return isolate->heap()->NumberFromDouble(value);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringParseFloat) {
   NoHandleAllocation ha;
-  CONVERT_CHECKED(String, str, args[0]);
+  CONVERT_CHECKED(String, str, 0);
 
   // ECMA-262 section 15.1.2.3, empty string is NaN
   double value = StringToDouble(isolate->unicode_cache(),
                                 str, ALLOW_TRAILING_JUNK, OS::nan_value());
 
   // Create a number object from the value.
   return isolate->heap()->NumberFromDouble(value);
 }
 
 
@@ skipping 228 matching lines @@
 
 }  // namespace
 
 
 template <typename ConvertTraits>
 MUST_USE_RESULT static MaybeObject* ConvertCase(
     Arguments args,
     Isolate* isolate,
     unibrow::Mapping<typename ConvertTraits::UnibrowConverter, 128>* mapping) {
   NoHandleAllocation ha;
-  CONVERT_CHECKED(String, s, args[0]);
+  CONVERT_CHECKED(String, s, 0);
   s = s->TryFlattenGetString();
 
   const int length = s->length();
   // Assume that the string is not empty; we need this assumption later
   if (length == 0) return s;
 
   // Simpler handling of ASCII strings.
   //
   // NOTE: This assumes that the upper/lower case of an ASCII
   // character is also ASCII.  This is currently the case, but it
@@ skipping 41 matching lines @@
 
 static inline bool IsTrimWhiteSpace(unibrow::uchar c) {
   return unibrow::WhiteSpace::Is(c) || c == 0x200b || c == 0xfeff;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringTrim) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 3);
 
-  CONVERT_CHECKED(String, s, args[0]);
-  CONVERT_BOOLEAN_CHECKED(trimLeft, args[1]);
-  CONVERT_BOOLEAN_CHECKED(trimRight, args[2]);
+  CONVERT_CHECKED(String, s, 0);
+  CONVERT_BOOLEAN_CHECKED(trimLeft, 1);
+  CONVERT_BOOLEAN_CHECKED(trimRight, 2);
 
   s->TryFlatten();
   int length = s->length();
 
   int left = 0;
   if (trimLeft) {
     while (left < length && IsTrimWhiteSpace(s->Get(left))) {
       left++;
     }
   }
@@ skipping 177 matching lines @@
   }
 #endif
 
   return *isolate->factory()->NewJSArrayWithElements(elements);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewStringWrapper) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(String, value, args[0]);
+  CONVERT_CHECKED(String, value, 0);
   return value->ToObject();
 }
 
 
 bool Runtime::IsUpperCaseChar(RuntimeState* runtime_state, uint16_t ch) {
   unibrow::uchar chars[unibrow::ToUppercase::kMaxWidth];
   int char_length = runtime_state->to_upper_mapping()->get(ch, 0, chars);
   return char_length == 0;
 }
 
@@ skipping 170 matching lines @@
 
   x = modulo(x, y);
   // NumberFromDouble may return a Smi instead of a Number object
   return isolate->heap()->NumberFromDouble(x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringAdd) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(String, str1, args[0]);
-  CONVERT_CHECKED(String, str2, args[1]);
+  CONVERT_CHECKED(String, str1, 0);
+  CONVERT_CHECKED(String, str2, 1);
   isolate->counters()->string_add_runtime()->Increment();
   return isolate->heap()->AllocateConsString(str1, str2);
 }
 
 
 template <typename sinkchar>
 static inline void StringBuilderConcatHelper(String* special,
                                              sinkchar* sink,
                                              FixedArray* fixed_array,
                                              int array_length) {
@@ skipping 27 matching lines @@
       String::WriteToFlat(string, sink + position, 0, element_length);
       position += element_length;
     }
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringBuilderConcat) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 3);
-  CONVERT_CHECKED(JSArray, array, args[0]);
+  CONVERT_CHECKED(JSArray, array, 0);
   if (!args[1]->IsSmi()) {
     isolate->context()->mark_out_of_memory();
     return Failure::OutOfMemoryException();
   }
   int array_length = args.smi_at(1);
-  CONVERT_CHECKED(String, special, args[2]);
+  CONVERT_CHECKED(String, special, 2);
 
   // This assumption is used by the slice encoding in one or two smis.
   ASSERT(Smi::kMaxValue >= String::kMaxLength);
 
   MaybeObject* maybe_result = array->EnsureCanContainHeapObjectElements();
   if (maybe_result->IsFailure()) return maybe_result;
 
   int special_length = special->length();
   if (!array->HasFastElements()) {
     return isolate->Throw(isolate->heap()->illegal_argument_symbol());
@@ skipping 89 matching lines @@
                               fixed_array,
                               array_length);
     return answer;
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringBuilderJoin) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 3);
-  CONVERT_CHECKED(JSArray, array, args[0]);
+  CONVERT_CHECKED(JSArray, array, 0);
   if (!args[1]->IsSmi()) {
     isolate->context()->mark_out_of_memory();
     return Failure::OutOfMemoryException();
   }
   int array_length = args.smi_at(1);
-  CONVERT_CHECKED(String, separator, args[2]);
+  CONVERT_CHECKED(String, separator, 2);
 
   if (!array->HasFastElements()) {
     return isolate->Throw(isolate->heap()->illegal_argument_symbol());
   }
   FixedArray* fixed_array = FixedArray::cast(array->elements());
   if (fixed_array->length() < array_length) {
     array_length = fixed_array->length();
   }
 
   if (array_length == 0) {
@@ skipping 97 matching lines @@
       previous_separator_position++;
     }
   }
   ASSERT(cursor <= buffer.length());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SparseJoinWithSeparator) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 3);
-  CONVERT_CHECKED(JSArray, elements_array, args[0]);
+  CONVERT_CHECKED(JSArray, elements_array, 0);
   RUNTIME_ASSERT(elements_array->HasFastElements() ||
                  elements_array->HasFastSmiOnlyElements());
   CONVERT_NUMBER_CHECKED(uint32_t, array_length, Uint32, args[1]);
-  CONVERT_CHECKED(String, separator, args[2]);
+  CONVERT_CHECKED(String, separator, 2);
   // elements_array is fast-mode JSarray of alternating positions
   // (increasing order) and strings.
   // array_length is length of original array (used to add separators);
   // separator is string to put between elements. Assumed to be non-empty.
 
   // Find total length of join result.
   int string_length = 0;
   bool is_ascii = separator->IsAsciiRepresentation();
   int max_string_length;
   if (is_ascii) {
     max_string_length = SeqAsciiString::kMaxLength;
   } else {
     max_string_length = SeqTwoByteString::kMaxLength;
   }
   bool overflow = false;
   CONVERT_NUMBER_CHECKED(int, elements_length,
                          Int32, elements_array->length());
   RUNTIME_ASSERT((elements_length & 1) == 0);  // Even length.
   FixedArray* elements = FixedArray::cast(elements_array->elements());
   for (int i = 0; i < elements_length; i += 2) {
     RUNTIME_ASSERT(elements->get(i)->IsNumber());
-    CONVERT_CHECKED(String, string, elements->get(i + 1));
+    RUNTIME_ASSERT(elements->get(i + 1)->IsString());
+    String* string = String::cast(elements->get(i + 1));
     int length = string->length();
     if (is_ascii && !string->IsAsciiRepresentation()) {
       is_ascii = false;
       max_string_length = SeqTwoByteString::kMaxLength;
     }
     if (length > max_string_length ||
         max_string_length - length < string_length) {
       overflow = true;
       break;
     }
@@ skipping 137 matching lines @@
     result = Smi::FromInt(NOT_EQUAL);
   }
   return result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringEquals) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(String, x, args[0]);
-  CONVERT_CHECKED(String, y, args[1]);
+  CONVERT_CHECKED(String, x, 0);
+  CONVERT_CHECKED(String, y, 1);
 
   bool not_equal = !x->Equals(y);
   // This is slightly convoluted because the value that signifies
   // equality is 0 and inequality is 1 so we have to negate the result
   // from String::Equals.
   ASSERT(not_equal == 0 || not_equal == 1);
   STATIC_CHECK(EQUAL == 0);
   STATIC_CHECK(NOT_EQUAL == 1);
   return Smi::FromInt(not_equal);
 }
@@ skipping 10 matching lines @@
   if (isless(x, y)) return Smi::FromInt(LESS);
   return Smi::FromInt(GREATER);
 }
 
 
 // Compare two Smis as if they were converted to strings and then
 // compared lexicographically.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SmiLexicographicCompare) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
-
-  // Extract the integer values from the Smis.
-  CONVERT_CHECKED(Smi, x, args[0]);
-  CONVERT_CHECKED(Smi, y, args[1]);
-  int x_value = x->value();
-  int y_value = y->value();
+  CONVERT_SMI_ARG_CHECKED(x_value, 0);
+  CONVERT_SMI_ARG_CHECKED(y_value, 1);
 
   // If the integers are equal so are the string representations.
   if (x_value == y_value) return Smi::FromInt(EQUAL);
 
   // If one of the integers is zero the normal integer order is the
   // same as the lexicographic order of the string representations.
   if (x_value == 0 || y_value == 0)
     return Smi::FromInt(x_value < y_value ? LESS : GREATER);
 
   // If only one of the integers is negative the negative number is
@@ skipping 119 matching lines @@
   ASSERT(result ==
       StringInputBufferCompare(Isolate::Current()->runtime_state(), x, y));
   return result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringCompare) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
-  CONVERT_CHECKED(String, x, args[0]);
-  CONVERT_CHECKED(String, y, args[1]);
+  CONVERT_CHECKED(String, x, 0);
+  CONVERT_CHECKED(String, y, 1);
 
   isolate->counters()->string_compare_runtime()->Increment();
 
   // A few fast case tests before we flatten.
   if (x == y) return Smi::FromInt(EQUAL);
   if (y->length() == 0) {
     if (x->length() == 0) return Smi::FromInt(EQUAL);
     return Smi::FromInt(GREATER);
   } else if (x->length() == 0) {
     return Smi::FromInt(LESS);
@@ skipping 586 matching lines @@
     DateYMDFromTimeSlow(date, year, month, day);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DateYMDFromTime) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(t, 0);
-  CONVERT_CHECKED(JSArray, res_array, args[1]);
+  CONVERT_CHECKED(JSArray, res_array, 1);
 
   int year, month, day;
   DateYMDFromTime(static_cast<int>(floor(t / 86400000)), year, month, day);
 
   FixedArrayBase* elms_base = FixedArrayBase::cast(res_array->elements());
   RUNTIME_ASSERT(elms_base->length() == 3);
   RUNTIME_ASSERT(res_array->HasFastTypeElements());
 
   MaybeObject* maybe = res_array->EnsureWritableFastElements();
   if (maybe->IsFailure()) return maybe;
@@ skipping 136 matching lines @@
   }
   return result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewClosure) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 3);
   CONVERT_ARG_CHECKED(Context, context, 0);
   CONVERT_ARG_CHECKED(SharedFunctionInfo, shared, 1);
-  CONVERT_BOOLEAN_CHECKED(pretenure, args[2]);
+  CONVERT_BOOLEAN_CHECKED(pretenure, 2);
 
   // The caller ensures that we pretenure closures that are assigned
   // directly to properties.
   PretenureFlag pretenure_flag = pretenure ? TENURED : NOT_TENURED;
   Handle<JSFunction> result =
       isolate->factory()->NewFunctionFromSharedFunctionInfo(shared,
                                                             context,
                                                             pretenure_flag);
   return *result;
 }
@@ skipping 635 matching lines @@
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CheckIsBootstrapping) {
   RUNTIME_ASSERT(isolate->bootstrapper()->IsActive());
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Call) {
   HandleScope scope(isolate);
   ASSERT(args.length() >= 2);
-  CONVERT_CHECKED(JSReceiver, fun, args[args.length() - 1]);
+  int argc = args.length() - 2;
+  CONVERT_CHECKED(JSReceiver, fun, argc + 1);
   Object* receiver = args[0];
-  int argc = args.length() - 2;
 
   // If there are too many arguments, allocate argv via malloc.
   const int argv_small_size = 10;
   Handle<Object> argv_small_buffer[argv_small_size];
   SmartArrayPointer<Handle<Object> > argv_large_buffer;
   Handle<Object>* argv = argv_small_buffer;
   if (argc > argv_small_size) {
     argv = new Handle<Object>[argc];
     if (argv == NULL) return isolate->StackOverflow();
     argv_large_buffer = SmartArrayPointer<Handle<Object> >(argv);
@@ skipping 65 matching lines @@
   ASSERT(args.length() == 1);
   RUNTIME_ASSERT(!args[0]->IsJSFunction());
   return *Execution::GetConstructorDelegate(args.at<Object>(0));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewFunctionContext) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, function, args[0]);
+  CONVERT_CHECKED(JSFunction, function, 0);
   int length = function->shared()->scope_info()->ContextLength();
   Object* result;
   { MaybeObject* maybe_result =
         isolate->heap()->AllocateFunctionContext(length, function);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
 
   isolate->set_context(Context::cast(result));
 
   return result;  // non-failure
@@ skipping 761 matching lines @@
     return maybe_allocation;
   }
 }
 
 
 // Push an object unto an array of objects if it is not already in the
 // array.  Returns true if the element was pushed on the stack and
 // false otherwise.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PushIfAbsent) {
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(JSArray, array, args[0]);
-  CONVERT_CHECKED(JSObject, element, args[1]);
+  CONVERT_CHECKED(JSArray, array, 0);
+  CONVERT_CHECKED(JSObject, element, 1);
   RUNTIME_ASSERT(array->HasFastElements() || array->HasFastSmiOnlyElements());
   int length = Smi::cast(array->length())->value();
   FixedArray* elements = FixedArray::cast(array->elements());
   for (int i = 0; i < length; i++) {
     if (elements->get(i) == element) return isolate->heap()->false_value();
   }
   Object* obj;
   // Strict not needed. Used for cycle detection in Array join implementation.
   { MaybeObject* maybe_obj =
         array->SetFastElement(length, element, kNonStrictMode, true);
@@ skipping 565 matching lines @@
   return *visitor.ToArray();
 }
 
 
 // This will not allocate (flatten the string), but it may run
 // very slowly for very deeply nested ConsStrings.  For debugging use only.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GlobalPrint) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(String, string, args[0]);
+  CONVERT_CHECKED(String, string, 0);
   StringInputBuffer buffer(string);
   while (buffer.has_more()) {
     uint16_t character = buffer.GetNext();
     PrintF("%c", character);
   }
   return string;
 }
 
 // Moves all own elements of an object, that are below a limit, to positions
 // starting at zero. All undefined values are placed after non-undefined values,
 // and are followed by non-existing element. Does not change the length
 // property.
 // Returns the number of non-undefined elements collected.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RemoveArrayHoles) {
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(JSObject, object, args[0]);
+  CONVERT_CHECKED(JSObject, object, 0);
   CONVERT_NUMBER_CHECKED(uint32_t, limit, Uint32, args[1]);
   return object->PrepareElementsForSort(limit);
 }
 
 
 // Move contents of argument 0 (an array) to argument 1 (an array)
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MoveArrayContents) {
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(JSArray, from, args[0]);
-  CONVERT_CHECKED(JSArray, to, args[1]);
+  CONVERT_CHECKED(JSArray, from, 0);
+  CONVERT_CHECKED(JSArray, to, 1);
   FixedArrayBase* new_elements = from->elements();
   MaybeObject* maybe_new_map;
   ElementsKind elements_kind;
   if (new_elements->map() == isolate->heap()->fixed_array_map() ||
       new_elements->map() == isolate->heap()->fixed_cow_array_map()) {
     elements_kind = FAST_ELEMENTS;
   } else if (new_elements->map() ==
              isolate->heap()->fixed_double_array_map()) {
     elements_kind = FAST_DOUBLE_ELEMENTS;
   } else {
@@ skipping 10 matching lines @@
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   from->set_length(Smi::FromInt(0));
   return to;
 }
 
 
 // How many elements does this object/array have?
 RUNTIME_FUNCTION(MaybeObject*, Runtime_EstimateNumberOfElements) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSObject, object, args[0]);
+  CONVERT_CHECKED(JSObject, object, 0);
   HeapObject* elements = object->elements();
   if (elements->IsDictionary()) {
     int result = SeededNumberDictionary::cast(elements)->NumberOfElements();
     return Smi::FromInt(result);
   } else if (object->IsJSArray()) {
     return JSArray::cast(object)->length();
   } else {
     return Smi::FromInt(FixedArray::cast(elements)->length());
   }
 }
@@ skipping 79 matching lines @@
 // DefineAccessor takes an optional final argument which is the
 // property attributes (e.g. DONT_ENUM, DONT_DELETE).  IMPORTANT: due
 // to the way accessors are implemented, it is set for both the getter
 // and setter on the first call to DefineAccessor and ignored on
 // subsequent calls.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DefineAccessor) {
   RUNTIME_ASSERT(args.length() == 4 || args.length() == 5);
   // Compute attributes.
   PropertyAttributes attributes = NONE;
   if (args.length() == 5) {
-    CONVERT_CHECKED(Smi, attrs, args[4]);
-    int value = attrs->value();
+    CONVERT_SMI_ARG_CHECKED(value, 4);
     // Only attribute bits should be set.
     ASSERT((value & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
     attributes = static_cast<PropertyAttributes>(value);
   }
 
-  CONVERT_CHECKED(JSObject, obj, args[0]);
-  CONVERT_CHECKED(String, name, args[1]);
-  CONVERT_CHECKED(Smi, flag, args[2]);
-  CONVERT_CHECKED(JSFunction, fun, args[3]);
-  return obj->DefineAccessor(name, flag->value() == 0, fun, attributes);
+  CONVERT_CHECKED(JSObject, obj, 0);
+  CONVERT_CHECKED(String, name, 1);
+  CONVERT_SMI_ARG_CHECKED(flag, 2);
+  CONVERT_CHECKED(JSFunction, fun, 3);
+  return obj->DefineAccessor(name, flag == 0, fun, attributes);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LookupAccessor) {
   ASSERT(args.length() == 3);
-  CONVERT_CHECKED(JSObject, obj, args[0]);
-  CONVERT_CHECKED(String, name, args[1]);
-  CONVERT_CHECKED(Smi, flag, args[2]);
-  return obj->LookupAccessor(name, flag->value() == 0);
+  CONVERT_CHECKED(JSObject, obj, 0);
+  CONVERT_CHECKED(String, name, 1);
+  CONVERT_SMI_ARG_CHECKED(flag, 2);
+  return obj->LookupAccessor(name, flag == 0);
 }
 
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugBreak) {
   ASSERT(args.length() == 0);
   return Execution::DebugBreakHelper();
 }
 
 
 // Helper functions for wrapping and unwrapping stack frame ids.
 static Smi* WrapFrameId(StackFrame::Id id) {
   ASSERT(IsAligned(OffsetFrom(id), static_cast<intptr_t>(4)));
   return Smi::FromInt(id >> 2);
 }
 
 
-static StackFrame::Id UnwrapFrameId(Smi* wrapped) {
-  return static_cast<StackFrame::Id>(wrapped->value() << 2);
+static StackFrame::Id UnwrapFrameId(int wrapped) {
+  return static_cast<StackFrame::Id>(wrapped << 2);
 }
 
 
 // Adds a JavaScript function as a debug event listener.
 // args[0]: debug event listener function to set or null or undefined for
 //          clearing the event listener function
 // args[1]: object supplied during callback
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetDebugEventListener) {
   ASSERT(args.length() == 2);
   RUNTIME_ASSERT(args[0]->IsJSFunction() ||
@@ skipping 196 matching lines @@
     return DebugLookupResultValue(isolate->heap(), *obj, *name, &result, NULL);
   }
   return isolate->heap()->undefined_value();
 }
 
 
 // Return the property type calculated from the property details.
 // args[0]: smi with property details.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPropertyTypeFromDetails) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(Smi, details, args[0]);
-  PropertyType type = PropertyDetails(details).type();
-  return Smi::FromInt(static_cast<int>(type));
+  CONVERT_PROPERTY_DETAILS_CHECKED(details, 0);
+  return Smi::FromInt(static_cast<int>(details.type()));
 }
 
 
 // Return the property attribute calculated from the property details.
 // args[0]: smi with property details.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPropertyAttributesFromDetails) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(Smi, details, args[0]);
-  PropertyAttributes attributes = PropertyDetails(details).attributes();
-  return Smi::FromInt(static_cast<int>(attributes));
+  CONVERT_PROPERTY_DETAILS_CHECKED(details, 0);
+  return Smi::FromInt(static_cast<int>(details.attributes()));
 }
 
 
 // Return the property insertion index calculated from the property details.
 // args[0]: smi with property details.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPropertyIndexFromDetails) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(Smi, details, args[0]);
-  int index = PropertyDetails(details).index();
-  return Smi::FromInt(index);
+  CONVERT_PROPERTY_DETAILS_CHECKED(details, 0);
+  return Smi::FromInt(details.index());
 }
 
 
 // Return property value from named interceptor.
 // args[0]: object
 // args[1]: property name
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugNamedInterceptorPropertyValue) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
@@ skipping 940 matching lines @@
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetScopeCount) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
 
   // Check arguments.
   Object* check;
   { MaybeObject* maybe_check = Runtime_CheckExecutionState(
       RUNTIME_ARGUMENTS(isolate, args));
     if (!maybe_check->ToObject(&check)) return maybe_check;
   }
-  CONVERT_CHECKED(Smi, wrapped_id, args[1]);
+  CONVERT_SMI_ARG_CHECKED(wrapped_id, 1);
 
   // Get the frame where the debugging is performed.
   StackFrame::Id id = UnwrapFrameId(wrapped_id);
   JavaScriptFrameIterator it(isolate, id);
   JavaScriptFrame* frame = it.frame();
 
   // Count the visible scopes.
   int n = 0;
   for (ScopeIterator it(isolate, frame, 0);
        !it.Done();
@@ skipping 21 matching lines @@
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetScopeDetails) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 4);
 
   // Check arguments.
   Object* check;
   { MaybeObject* maybe_check = Runtime_CheckExecutionState(
       RUNTIME_ARGUMENTS(isolate, args));
     if (!maybe_check->ToObject(&check)) return maybe_check;
   }
-  CONVERT_CHECKED(Smi, wrapped_id, args[1]);
+  CONVERT_SMI_ARG_CHECKED(wrapped_id, 1);
   CONVERT_NUMBER_CHECKED(int, inlined_jsframe_index, Int32, args[2]);
   CONVERT_NUMBER_CHECKED(int, index, Int32, args[3]);
 
   // Get the frame where the debugging is performed.
   StackFrame::Id id = UnwrapFrameId(wrapped_id);
   JavaScriptFrameIterator frame_it(isolate, id);
   JavaScriptFrame* frame = frame_it.frame();
 
   // Find the requested scope.
   int n = 0;
@@ skipping 119 matching lines @@
   // Convert to JS array and return.
   return *isolate->factory()->NewJSArrayWithElements(details);
 }
 
 
 // Sets the disable break state
 // args[0]: disable break state
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetDisableBreak) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
-  CONVERT_BOOLEAN_CHECKED(disable_break, args[0]);
+  CONVERT_BOOLEAN_CHECKED(disable_break, 0);
   isolate->debug()->set_disable_break(disable_break);
   return  isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetBreakLocations) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, fun, 0);
@@ skipping 163 matching lines @@
 }
 
 
 // Change the state of break on exceptions.
 // args[0]: Enum value indicating whether to affect caught/uncaught exceptions.
 // args[1]: Boolean indicating on/off.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ChangeBreakOnException) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
   RUNTIME_ASSERT(args[0]->IsNumber());
-  CONVERT_BOOLEAN_CHECKED(enable, args[1]);
+  CONVERT_BOOLEAN_CHECKED(enable, 1);
 
   // If the number doesn't match an enum value, the ChangeBreakOnException
   // function will default to affecting caught exceptions.
   ExceptionBreakType type =
       static_cast<ExceptionBreakType>(NumberToUint32(args[0]));
   // Update break point state.
   isolate->debug()->ChangeBreakOnException(type, enable);
   return isolate->heap()->undefined_value();
 }
 
@@ skipping 194 matching lines @@
   // Check the execution state and decode arguments frame and source to be
   // evaluated.
   ASSERT(args.length() == 6);
   Object* check_result;
   { MaybeObject* maybe_check_result = Runtime_CheckExecutionState(
       RUNTIME_ARGUMENTS(isolate, args));
     if (!maybe_check_result->ToObject(&check_result)) {
       return maybe_check_result;
     }
   }
-  CONVERT_CHECKED(Smi, wrapped_id, args[1]);
+  CONVERT_SMI_ARG_CHECKED(wrapped_id, 1);
   CONVERT_NUMBER_CHECKED(int, inlined_jsframe_index, Int32, args[2]);
   CONVERT_ARG_CHECKED(String, source, 3);
-  CONVERT_BOOLEAN_CHECKED(disable_break, args[4]);
+  CONVERT_BOOLEAN_CHECKED(disable_break, 4);
   Handle<Object> additional_context(args[5]);
 
   // Handle the processing of break.
   DisableBreak disable_break_save(disable_break);
 
   // Get the frame where the debugging is performed.
   StackFrame::Id id = UnwrapFrameId(wrapped_id);
   JavaScriptFrameIterator it(isolate, id);
   JavaScriptFrame* frame = it.frame();
   FrameInspector frame_inspector(frame, inlined_jsframe_index, isolate);
@@ skipping 116 matching lines @@
   // evaluated.
   ASSERT(args.length() == 4);
   Object* check_result;
   { MaybeObject* maybe_check_result = Runtime_CheckExecutionState(
       RUNTIME_ARGUMENTS(isolate, args));
     if (!maybe_check_result->ToObject(&check_result)) {
       return maybe_check_result;
     }
   }
   CONVERT_ARG_CHECKED(String, source, 1);
-  CONVERT_BOOLEAN_CHECKED(disable_break, args[2]);
+  CONVERT_BOOLEAN_CHECKED(disable_break, 2);
   Handle<Object> additional_context(args[3]);
 
   // Handle the processing of break.
   DisableBreak disable_break_save(disable_break);
 
   // Enter the top context from before the debugger was invoked.
   SaveContext save(isolate);
   SaveContext* top = &save;
   while (top != NULL && *top->context() == *isolate->debug()->debug_context()) {
     top = top->prev();
@@ skipping 152 matching lines @@
 
   // First perform a full GC in order to avoid references from dead objects.
   isolate->heap()->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                                      "%DebugReferencedBy");
   // The heap iterator reserves the right to do a GC to make the heap iterable.
   // Due to the GC above we know it won't need to do that, but it seems cleaner
   // to get the heap iterator constructed before we start having unprotected
   // Object* locals that are not protected by handles.
 
   // Check parameters.
-  CONVERT_CHECKED(JSObject, target, args[0]);
+  CONVERT_CHECKED(JSObject, target, 0);
   Object* instance_filter = args[1];
   RUNTIME_ASSERT(instance_filter->IsUndefined() ||
                  instance_filter->IsJSObject());
   CONVERT_NUMBER_CHECKED(int32_t, max_references, Int32, args[2]);
   RUNTIME_ASSERT(max_references >= 0);
 
 
   // Get the constructor function for context extension and arguments array.
   JSObject* arguments_boilerplate =
       isolate->context()->global_context()->arguments_boilerplate();
@@ skipping 67 matching lines @@
 // args[0]: the constructor to find instances of
 // args[1]: the the maximum number of objects to return
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugConstructedBy) {
   ASSERT(args.length() == 2);
 
   // First perform a full GC in order to avoid dead objects.
   isolate->heap()->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                                      "%DebugConstructedBy");
 
   // Check parameters.
-  CONVERT_CHECKED(JSFunction, constructor, args[0]);
+  CONVERT_CHECKED(JSFunction, constructor, 0);
   CONVERT_NUMBER_CHECKED(int32_t, max_references, Int32, args[1]);
   RUNTIME_ASSERT(max_references >= 0);
 
   // Get the number of referencing objects.
   int count;
   HeapIterator heap_iterator;
   count = DebugConstructedBy(&heap_iterator,
                              constructor,
                              max_references,
                              NULL,
@@ skipping 23 matching lines @@
   }
   return JSArray::cast(result)->SetContent(instances);
 }
 
 
 // Find the effective prototype object as returned by __proto__.
 // args[0]: the object to find the prototype for.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugGetPrototype) {
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSObject, obj, args[0]);
+  CONVERT_CHECKED(JSObject, obj, 0);
 
   // Use the __proto__ accessor.
   return Accessors::ObjectPrototype.getter(obj, NULL);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SystemBreak) {
   ASSERT(args.length() == 0);
   CPU::DebugBreak();
   return isolate->heap()->undefined_value();
@@ skipping 29 matching lines @@
   shared->construct_stub()->PrintLn();
 #endif  // DEBUG
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetInferredName) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(JSFunction, f, args[0]);
+  CONVERT_CHECKED(JSFunction, f, 0);
   return f->shared()->inferred_name();
 }
 
 
 static int FindSharedFunctionInfosForScript(HeapIterator* iterator,
                                             Script* script,
                                             FixedArray* buffer) {
   AssertNoAllocation no_allocations;
   int counter = 0;
   int buffer_size = buffer->length();
@@ skipping 16 matching lines @@
   return counter;
 }
 
 // For a script finds all SharedFunctionInfo's in the heap that points
 // to this script. Returns JSArray of SharedFunctionInfo wrapped
 // in OpaqueReferences.
 RUNTIME_FUNCTION(MaybeObject*,
                  Runtime_LiveEditFindSharedFunctionInfosForScript) {
   ASSERT(args.length() == 1);
   HandleScope scope(isolate);
-  CONVERT_CHECKED(JSValue, script_value, args[0]);
+  CONVERT_CHECKED(JSValue, script_value, 0);
 
 
   Handle<Script> script = Handle<Script>(Script::cast(script_value->value()));
 
   const int kBufferSize = 32;
 
   Handle<FixedArray> array;
   array = isolate->factory()->NewFixedArray(kBufferSize);
   int number;
   {
@@ skipping 25 matching lines @@
 // For a script calculates compilation information about all its functions.
 // The script source is explicitly specified by the second argument.
 // The source of the actual script is not used, however it is important that
 // all generated code keeps references to this particular instance of script.
 // Returns a JSArray of compilation infos. The array is ordered so that
 // each function with all its descendant is always stored in a continues range
 // with the function itself going first. The root function is a script function.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LiveEditGatherCompileInfo) {
   ASSERT(args.length() == 2);
   HandleScope scope(isolate);
-  CONVERT_CHECKED(JSValue, script, args[0]);
+  CONVERT_CHECKED(JSValue, script, 0);
   CONVERT_ARG_CHECKED(String, source, 1);
   Handle<Script> script_handle = Handle<Script>(Script::cast(script->value()));
 
   JSArray* result =  LiveEdit::GatherCompileInfo(script_handle, source);
 
   if (isolate->has_pending_exception()) {
     return Failure::Exception();
   }
 
   return result;
 }
 
 // Changes the source of the script to a new_source.
 // If old_script_name is provided (i.e. is a String), also creates a copy of
 // the script with its original source and sends notification to debugger.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LiveEditReplaceScript) {
   ASSERT(args.length() == 3);
   HandleScope scope(isolate);
-  CONVERT_CHECKED(JSValue, original_script_value, args[0]);
+  CONVERT_CHECKED(JSValue, original_script_value, 0);
   CONVERT_ARG_CHECKED(String, new_source, 1);
   Handle<Object> old_script_name(args[2], isolate);
 
-  CONVERT_CHECKED(Script, original_script_pointer,
-                  original_script_value->value());
-  Handle<Script> original_script(original_script_pointer);
+  RUNTIME_ASSERT(original_script_value->value()->IsScript());
+  Handle<Script> original_script(Script::cast(original_script_value->value()));
 
   Object* old_script = LiveEdit::ChangeScriptSource(original_script,
                                                     new_source,
                                                     old_script_name);
 
   if (old_script->IsScript()) {
     Handle<Script> script_handle(Script::cast(old_script));
     return *(GetScriptWrapper(script_handle));
   } else {
     return isolate->heap()->null_value();
@@ skipping 22 matching lines @@
 // Connects SharedFunctionInfo to another script.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LiveEditFunctionSetScript) {
   ASSERT(args.length() == 2);
   HandleScope scope(isolate);
   Handle<Object> function_object(args[0], isolate);
   Handle<Object> script_object(args[1], isolate);
 
   if (function_object->IsJSValue()) {
     Handle<JSValue> function_wrapper = Handle<JSValue>::cast(function_object);
     if (script_object->IsJSValue()) {
-      CONVERT_CHECKED(Script, script, JSValue::cast(*script_object)->value());
+      RUNTIME_ASSERT(JSValue::cast(*script_object)->value()->IsScript());
+      Script* script = Script::cast(JSValue::cast(*script_object)->value());
       script_object = Handle<Object>(script, isolate);
     }
 
     LiveEdit::SetFunctionScript(function_wrapper, script_object);
   } else {
     // Just ignore this. We may not have a SharedFunctionInfo for some functions
     // and we check it in this function.
   }
 
   return isolate->heap()->undefined_value();
@@ skipping 33 matching lines @@
 
 
 // For array of SharedFunctionInfo's (each wrapped in JSValue)
 // checks that none of them have activations on stacks (of any thread).
 // Returns array of the same length with corresponding results of
 // LiveEdit::FunctionPatchabilityStatus type.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LiveEditCheckAndDropActivations) {
   ASSERT(args.length() == 2);
   HandleScope scope(isolate);
   CONVERT_ARG_CHECKED(JSArray, shared_array, 0);
-  CONVERT_BOOLEAN_CHECKED(do_drop, args[1]);
+  CONVERT_BOOLEAN_CHECKED(do_drop, 1);
 
   return *LiveEdit::CheckAndDropActivations(shared_array, do_drop);
 }
 
 // Compares 2 strings line-by-line, then token-wise and returns diff in form
 // of JSArray of triplets (pos1, pos1_end, pos2_end) describing list
 // of diff chunks.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LiveEditCompareStrings) {
   ASSERT(args.length() == 2);
   HandleScope scope(isolate);
@@ skipping 40 matching lines @@
 }
 
 
 // Calls specified function with or without entering the debugger.
 // This is used in unit tests to run code as if debugger is entered or simply
 // to have a stack with C++ frame in the middle.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ExecuteInDebugContext) {
   ASSERT(args.length() == 2);
   HandleScope scope(isolate);
   CONVERT_ARG_CHECKED(JSFunction, function, 0);
-  CONVERT_BOOLEAN_CHECKED(without_debugger, args[1]);
+  CONVERT_BOOLEAN_CHECKED(without_debugger, 1);
 
   Handle<Object> result;
   bool pending_exception;
   {
     if (without_debugger) {
       result = Execution::Call(function, isolate->global(), 0, NULL,
                                &pending_exception);
     } else {
       EnterDebugger enter_debugger;
       result = Execution::Call(function, isolate->global(), 0, NULL,
                                &pending_exception);
     }
   }
   if (!pending_exception) {
     return *result;
   } else {
     return Failure::Exception();
   }
 }
 
 
 // Sets a v8 flag.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetFlags) {
-  CONVERT_CHECKED(String, arg, args[0]);
+  CONVERT_CHECKED(String, arg, 0);
   SmartArrayPointer<char> flags =
       arg->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
   FlagList::SetFlagsFromString(*flags, StrLength(*flags));
   return isolate->heap()->undefined_value();
 }
 
 
 // Performs a GC.
 // Presently, it only does a full GC.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CollectGarbage) {
@@ skipping 263 matching lines @@
 
 
 // Get the script object from script data. NOTE: Regarding performance
 // see the NOTE for GetScriptFromScriptData.
 // args[0]: script data for the script to find the source for
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetScript) {
   HandleScope scope(isolate);
 
   ASSERT(args.length() == 1);
 
-  CONVERT_CHECKED(String, script_name, args[0]);
+  CONVERT_CHECKED(String, script_name, 0);
 
   // Find the requested script.
   Handle<Object> result =
       Runtime_GetScriptFromScriptName(Handle<String>(script_name));
   return *result;
 }
 
 
 // Determines whether the given stack frame should be displayed in
 // a stack trace.  The caller is the error constructor that asked
@@ skipping 119 matching lines @@
                  reinterpret_cast<char*>(args[0]) + args.smi_at(1));
   isolate->PrintStack();
   OS::Abort();
   UNREACHABLE();
   return NULL;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFromCache) {
   // This is only called from codegen, so checks might be more lax.
-  CONVERT_CHECKED(JSFunctionResultCache, cache, args[0]);
+  CONVERT_CHECKED(JSFunctionResultCache, cache, 0);
   Object* key = args[1];
 
   int finger_index = cache->finger_index();
   Object* o = cache->get(finger_index);
   if (o == key) {
     // The fastest case: hit the same place again.
     return cache->get(finger_index + 1);
   }
 
   for (int i = finger_index - 2;
@@ skipping 89 matching lines @@
       arguments,
       0,
       0,
       isolate->factory()->undefined_value(),
       isolate->factory()->undefined_value(),
       isolate->factory()->undefined_value());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MessageGetType) {
-  CONVERT_CHECKED(JSMessageObject, message, args[0]);
+  CONVERT_CHECKED(JSMessageObject, message, 0);
   return message->type();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MessageGetArguments) {
-  CONVERT_CHECKED(JSMessageObject, message, args[0]);
+  CONVERT_CHECKED(JSMessageObject, message, 0);
   return message->arguments();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MessageGetStartPosition) {
-  CONVERT_CHECKED(JSMessageObject, message, args[0]);
+  CONVERT_CHECKED(JSMessageObject, message, 0);
   return Smi::FromInt(message->start_position());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MessageGetScript) {
-  CONVERT_CHECKED(JSMessageObject, message, args[0]);
+  CONVERT_CHECKED(JSMessageObject, message, 0);
   return message->script();
 }
 
 
 #ifdef DEBUG
 // ListNatives is ONLY used by the fuzz-natives.js in debug mode
 // Exclude the code in release mode.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ListNatives) {
   ASSERT(args.length() == 0);
   HandleScope scope;
@@ skipping 33 matching lines @@
 #undef ADD_ENTRY
   ASSERT_EQ(index, entry_count);
   Handle<JSArray> result = factory->NewJSArrayWithElements(elements);
   return *result;
 }
 #endif
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Log) {
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(String, format, args[0]);
-  CONVERT_CHECKED(JSArray, elms, args[1]);
+  CONVERT_CHECKED(String, format, 0);
+  CONVERT_CHECKED(JSArray, elms, 1);
   String::FlatContent format_content = format->GetFlatContent();
   RUNTIME_ASSERT(format_content.IsAscii());
   Vector<const char> chars = format_content.ToAsciiVector();
   LOGGER->LogRuntime(chars, elms);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IS_VAR) {
   UNREACHABLE();  // implemented as macro in the parser
   return NULL;
 }
 
 
 #define ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(Name)        \
   RUNTIME_FUNCTION(MaybeObject*, Runtime_Has##Name) {     \
-    CONVERT_CHECKED(JSObject, obj, args[0]);              \
+    CONVERT_CHECKED(JSObject, obj, 0);              \
     return isolate->heap()->ToBoolean(obj->Has##Name());  \
   }
 
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(FastSmiOnlyElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(FastElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(FastDoubleElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(DictionaryElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalPixelElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalArrayElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalByteElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalUnsignedByteElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalShortElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalUnsignedShortElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalIntElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalUnsignedIntElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalFloatElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalDoubleElements)
 
 #undef ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HaveSameMap) {
   ASSERT(args.length() == 2);
-  CONVERT_CHECKED(JSObject, obj1, args[0]);
-  CONVERT_CHECKED(JSObject, obj2, args[1]);
+  CONVERT_CHECKED(JSObject, obj1, 0);
+  CONVERT_CHECKED(JSObject, obj2, 1);
   return isolate->heap()->ToBoolean(obj1->map() == obj2->map());
 }
 
 // ----------------------------------------------------------------------------
 // Implementation of Runtime
 
 #define F(name, number_of_args, result_size)                             \
   { Runtime::k##name, Runtime::RUNTIME, #name,   \
     FUNCTION_ADDR(Runtime_##name), number_of_args, result_size },
 
@@ skipping 68 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal