Remove special charAt and charCodeAt handling in the ICs.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/136443006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18663 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/stub-cache-arm.cc

@@ -1889,138 +1889,6 @@ Handle<Code> CallStubCompiler::CompileArrayPopCall(
 }
 
 
-Handle<Code> CallStubCompiler::CompileStringCharCodeAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) return Handle<Code>::null();
-
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-  Label* index_out_of_range_label = &index_out_of_range;
-
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = r0;
-  Register index = r4;
-  Register result = r1;
-  const int argc = arguments().immediate();
-  __ ldr(receiver, MemOperand(sp, argc * kPointerSize));
-  if (argc > 0) {
-    __ ldr(index, MemOperand(sp, (argc - 1) * kPointerSize));
-  } else {
-    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
-  }
-
-  StringCharCodeAtGenerator generator(receiver,
-                                      index,
-                                      result,
-                                      &miss,  // When not a string.
-                                      &miss,  // When not a number.
-                                      index_out_of_range_label,
-                                      STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ Drop(argc + 1);
-  __ mov(r0, result);
-  __ Ret();
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ LoadRoot(r0, Heap::kNanValueRootIndex);
-    __ Drop(argc + 1);
-    __ Ret();
-  }
-
-  __ bind(&miss);
-  // Restore function name in r2.
-  __ Move(r2, name);
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
-Handle<Code> CallStubCompiler::CompileStringCharAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) return Handle<Code>::null();
-
-  const int argc = arguments().immediate();
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-  Label* index_out_of_range_label = &index_out_of_range;
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = r0;
-  Register index = r4;
-  Register scratch = r3;
-  Register result = r1;
-  if (argc > 0) {
-    __ ldr(index, MemOperand(sp, (argc - 1) * kPointerSize));
-  } else {
-    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
-  }
-
-  StringCharAtGenerator generator(receiver,
-                                  index,
-                                  scratch,
-                                  result,
-                                  &miss,  // When not a string.
-                                  &miss,  // When not a number.
-                                  index_out_of_range_label,
-                                  STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ Drop(argc + 1);
-  __ mov(r0, result);
-  __ Ret();
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ LoadRoot(r0, Heap::kempty_stringRootIndex);
-    __ Drop(argc + 1);
-    __ Ret();
-  }
-
-  __ bind(&miss);
-  // Restore function name in r2.
-  __ Move(r2, name);
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
 Handle<Code> CallStubCompiler::CompileStringFromCharCodeCall(
     Handle<Object> object,
     Handle<JSObject> holder,

src/code-stubs.h

@@ -1087,13 +1087,9 @@ class KeyedArrayCallStub: public HICStub {
     return GetExtraICState() | ArgcBits::encode(argc_);
   }
 
-  // We have to start storing extra ic bits at 1, because calls use bit zero
-  // for string stub state.
-  STATIC_ASSERT(CallICBase::StringStubState::kShift == 0);
-  STATIC_ASSERT(CallICBase::StringStubState::kSize == 1);
-  class HoleyBits: public BitField<bool, 1, 1> {};
-  STATIC_ASSERT(Code::kArgumentsBits <= kStubMinorKeyBits - 2);
-  class ArgcBits: public BitField<int, 2, Code::kArgumentsBits> {};
+  class HoleyBits: public BitField<bool, 0, 1> {};
+  STATIC_ASSERT(Code::kArgumentsBits <= kStubMinorKeyBits - 1);
+  class ArgcBits: public BitField<int, 1, Code::kArgumentsBits> {};
   virtual CodeStub::Major MajorKey() { return KeyedArrayCall; }
   int bit_field_;
   int argc_;

src/ia32/stub-cache-ia32.cc

@@ -1981,140 +1981,6 @@ Handle<Code> CallStubCompiler::CompileArrayPopCall(
 }
 
 
-Handle<Code> CallStubCompiler::CompileStringCharCodeAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) {
-    return Handle<Code>::null();
-  }
-
-  const int argc = arguments().immediate();
-
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-  Label* index_out_of_range_label = &index_out_of_range;
-
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = ebx;
-  Register index = edi;
-  Register result = eax;
-  __ mov(receiver, Operand(esp, (argc + 1) * kPointerSize));
-  if (argc > 0) {
-    __ mov(index, Operand(esp, (argc - 0) * kPointerSize));
-  } else {
-    __ Set(index, Immediate(factory()->undefined_value()));
-  }
-
-  StringCharCodeAtGenerator generator(receiver,
-                                      index,
-                                      result,
-                                      &miss,  // When not a string.
-                                      &miss,  // When not a number.
-                                      index_out_of_range_label,
-                                      STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ ret((argc + 1) * kPointerSize);
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ Set(eax, Immediate(factory()->nan_value()));
-    __ ret((argc + 1) * kPointerSize);
-  }
-
-  __ bind(&miss);
-  // Restore function name in ecx.
-  __ Set(ecx, Immediate(name));
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
-Handle<Code> CallStubCompiler::CompileStringCharAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) {
-    return Handle<Code>::null();
-  }
-
-  const int argc = arguments().immediate();
-
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-  Label* index_out_of_range_label = &index_out_of_range;
-
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = eax;
-  Register index = edi;
-  Register scratch = edx;
-  Register result = eax;
-  __ mov(receiver, Operand(esp, (argc + 1) * kPointerSize));
-  if (argc > 0) {
-    __ mov(index, Operand(esp, (argc - 0) * kPointerSize));
-  } else {
-    __ Set(index, Immediate(factory()->undefined_value()));
-  }
-
-  StringCharAtGenerator generator(receiver,
-                                  index,
-                                  scratch,
-                                  result,
-                                  &miss,  // When not a string.
-                                  &miss,  // When not a number.
-                                  index_out_of_range_label,
-                                  STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ ret((argc + 1) * kPointerSize);
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ Set(eax, Immediate(factory()->empty_string()));
-    __ ret((argc + 1) * kPointerSize);
-  }
-
-  __ bind(&miss);
-  // Restore function name in ecx.
-  __ Set(ecx, Immediate(name));
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
 Handle<Code> CallStubCompiler::CompileStringFromCharCodeCall(
     Handle<Object> object,
     Handle<JSObject> holder,

src/ic.cc

@@ -231,57 +231,8 @@ static void LookupForRead(Handle<Object> object,
 }
 
 
-bool CallIC::TryUpdateExtraICState(LookupResult* lookup,
-                                   Handle<Object> object) {
-  if (!lookup->IsConstantFunction()) return false;
-  JSFunction* function = lookup->GetConstantFunction();
-  if (!function->shared()->HasBuiltinFunctionId()) return false;
-
-  // Fetch the arguments passed to the called function.
-  const int argc = target()->arguments_count();
-  Address entry = isolate()->c_entry_fp(isolate()->thread_local_top());
-  Address fp = Memory::Address_at(entry + ExitFrameConstants::kCallerFPOffset);
-  Arguments args(argc + 1,
-                 &Memory::Object_at(fp +
-                                    StandardFrameConstants::kCallerSPOffset +
-                                    argc * kPointerSize));
-  switch (function->shared()->builtin_function_id()) {
-    case kStringCharCodeAt:
-    case kStringCharAt:
-      if (object->IsString()) {
-        String* string = String::cast(*object);
-        // Check there's the right string value or wrapper in the receiver slot.
-        ASSERT(string == args[0] || string == JSValue::cast(args[0])->value());
-        // If we're in the default (fastest) state and the index is
-        // out of bounds, update the state to record this fact.
-        if (StringStubState::decode(extra_ic_state()) == DEFAULT_STRING_STUB &&
-            argc >= 1 && args[1]->IsNumber()) {
-          double index = DoubleToInteger(args.number_at(1));
-          if (index < 0 || index >= string->length()) {
-            set_extra_ic_state(StringStubState::update(extra_ic_state(),
-                STRING_INDEX_OUT_OF_BOUNDS));
-            return true;
-          }
-        }
-      }
-      break;
-    default:
-      return false;
-  }
-  return false;
-}
-
-
 bool IC::TryRemoveInvalidPrototypeDependentStub(Handle<Object> receiver,
                                                 Handle<String> name) {
-  if (target()->is_call_stub()) {
-    LookupResult lookup(isolate());
-    LookupForRead(receiver, name, &lookup);
-    if (static_cast<CallIC*>(this)->TryUpdateExtraICState(&lookup, receiver)) {
-      return true;
-    }
-  }
-
   if (target()->is_keyed_stub()) {
     // Determine whether the failure is due to a name failure.
     if (!name->IsName()) return false;

src/ic.h

@@ -283,20 +283,8 @@ class IC_Utility {
 };
 
 
-enum StringStubFeedback {
-  DEFAULT_STRING_STUB = 0,
-  STRING_INDEX_OUT_OF_BOUNDS = 1
-};
-
-
 class CallICBase: public IC {
  public:
-  // ExtraICState bits
-  class StringStubState: public BitField<StringStubFeedback, 0, 1> {};
-  static ExtraICState ComputeExtraICState(StringStubFeedback feedback) {
-    return StringStubState::encode(feedback);
-  }
-
   // Returns a JSFunction or a Failure.
   MUST_USE_RESULT MaybeObject* LoadFunction(Handle<Object> object,
                                             Handle<String> name);

src/mips/stub-cache-mips.cc

@@ -1872,135 +1872,6 @@ Handle<Code> CallStubCompiler::CompileArrayPopCall(
 }
 
 
-Handle<Code> CallStubCompiler::CompileStringCharCodeAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) return Handle<Code>::null();
-
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-
-  Label* index_out_of_range_label = &index_out_of_range;
-
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = a0;
-  Register index = t1;
-  Register result = a1;
-  const int argc = arguments().immediate();
-  __ lw(receiver, MemOperand(sp, argc * kPointerSize));
-  if (argc > 0) {
-    __ lw(index, MemOperand(sp, (argc - 1) * kPointerSize));
-  } else {
-    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
-  }
-
-  StringCharCodeAtGenerator generator(receiver,
-                                      index,
-                                      result,
-                                      &miss,  // When not a string.
-                                      &miss,  // When not a number.
-                                      index_out_of_range_label,
-                                      STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ mov(v0, result);
-  __ DropAndRet(argc + 1);
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ LoadRoot(v0, Heap::kNanValueRootIndex);
-    __ DropAndRet(argc + 1);
-  }
-
-  __ bind(&miss);
-  // Restore function name in a2.
-  __ li(a2, name);
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
-Handle<Code> CallStubCompiler::CompileStringCharAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) return Handle<Code>::null();
-
-  const int argc = arguments().immediate();
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-  Label* index_out_of_range_label = &index_out_of_range;
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = a0;
-  Register index = t1;
-  Register scratch = a3;
-  Register result = a1;
-  if (argc > 0) {
-    __ lw(index, MemOperand(sp, (argc - 1) * kPointerSize));
-  } else {
-    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
-  }
-
-  StringCharAtGenerator generator(receiver,
-                                  index,
-                                  scratch,
-                                  result,
-                                  &miss,  // When not a string.
-                                  &miss,  // When not a number.
-                                  index_out_of_range_label,
-                                  STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ mov(v0, result);
-  __ DropAndRet(argc + 1);
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ LoadRoot(v0, Heap::kempty_stringRootIndex);
-    __ DropAndRet(argc + 1);
-  }
-
-  __ bind(&miss);
-  // Restore function name in a2.
-  __ li(a2, name);
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
 Handle<Code> CallStubCompiler::CompileStringFromCharCodeCall(
     Handle<Object> object,
     Handle<JSObject> holder,

src/objects.cc

@@ -11100,11 +11100,6 @@ void Code::PrintExtraICState(FILE* out, Kind kind, ExtraICState extra) {
   PrintF(out, "extra_ic_state = ");
   const char* name = NULL;
   switch (kind) {
-    case CALL_IC:
-      if (extra == STRING_INDEX_OUT_OF_BOUNDS) {
-        name = "STRING_INDEX_OUT_OF_BOUNDS";
-      }
-      break;
     case STORE_IC:
     case KEYED_STORE_IC:
       if (extra == kStrictMode) {

src/stub-cache.cc

@@ -415,10 +415,8 @@ static void FillCache(Isolate* isolate, Handle<Code> code) {
 
 
 Code* StubCache::FindCallInitialize(int argc, Code::Kind kind) {
-  ExtraICState extra_state =
-      CallICBase::StringStubState::encode(DEFAULT_STRING_STUB);
-  Code::Flags flags =
-      Code::ComputeFlags(kind, UNINITIALIZED, extra_state, Code::NORMAL, argc);
+  Code::Flags flags = Code::ComputeFlags(
+      kind, UNINITIALIZED, kNoExtraICState, Code::NORMAL, argc);
   UnseededNumberDictionary* dictionary =
       isolate()->heap()->non_monomorphic_cache();
   int entry = dictionary->FindEntry(isolate(), flags);
@@ -444,10 +442,8 @@ Code* StubCache::FindPreMonomorphicIC(Code::Kind kind, ExtraICState state) {
 
 
 Handle<Code> StubCache::ComputeCallInitialize(int argc, Code::Kind kind) {
-  ExtraICState extra_state =
-      CallICBase::ComputeExtraICState(DEFAULT_STRING_STUB);
-  Code::Flags flags =
-      Code::ComputeFlags(kind, UNINITIALIZED, extra_state, Code::NORMAL, argc);
+  Code::Flags flags = Code::ComputeFlags(
+      kind, UNINITIALIZED, kNoExtraICState, Code::NORMAL, argc);
   Handle<UnseededNumberDictionary> cache =
       isolate_->factory()->non_monomorphic_cache();
   int entry = cache->FindEntry(isolate_, flags);

src/stub-cache.h

@@ -903,8 +903,6 @@ class KeyedStoreStubCompiler: public StoreStubCompiler {
 #define CUSTOM_CALL_IC_GENERATORS(V)            \
   V(ArrayPush)                                  \
   V(ArrayPop)                                   \
-  V(StringCharCodeAt)                           \
-  V(StringCharAt)                               \
   V(StringFromCharCode)                         \
   V(MathFloor)                                  \
   V(MathAbs)

src/type-info.cc

@@ -179,8 +179,6 @@ void TypeFeedbackOracle::CallReceiverTypes(TypeFeedbackId id,
                                            Handle<String> name,
                                            int arity,
                                            SmallMapList* types) {
-  // Note: Currently we do not take string extra ic data into account
-  // here.
   Code::Flags flags = Code::ComputeMonomorphicFlags(
       Code::CALL_IC, kNoExtraICState, OWN_MAP, Code::NORMAL, arity);
   CollectReceiverTypes(id, name, flags, types);

src/x64/stub-cache-x64.cc

@@ -1905,135 +1905,6 @@ Handle<Code> CallStubCompiler::CompileArrayPopCall(
 }
 
 
-Handle<Code> CallStubCompiler::CompileStringCharCodeAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) return Handle<Code>::null();
-
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-  Label* index_out_of_range_label = &index_out_of_range;
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = rbx;
-  Register index = rdi;
-  Register result = rax;
-  const int argc = arguments().immediate();
-  StackArgumentsAccessor args(rsp, argc);
-
-  __ movq(receiver, args.GetReceiverOperand());
-  if (argc > 0) {
-    __ movq(index, args.GetArgumentOperand(1));
-  } else {
-    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
-  }
-
-  StringCharCodeAtGenerator generator(receiver,
-                                      index,
-                                      result,
-                                      &miss,  // When not a string.
-                                      &miss,  // When not a number.
-                                      index_out_of_range_label,
-                                      STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ ret((argc + 1) * kPointerSize);
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ LoadRoot(rax, Heap::kNanValueRootIndex);
-    __ ret((argc + 1) * kPointerSize);
-  }
-
-  __ bind(&miss);
-  // Restore function name in rcx.
-  __ Move(rcx, name);
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
-Handle<Code> CallStubCompiler::CompileStringCharAtCall(
-    Handle<Object> object,
-    Handle<JSObject> holder,
-    Handle<Cell> cell,
-    Handle<JSFunction> function,
-    Handle<String> name,
-    Code::StubType type) {
-  // If object is not a string, bail out to regular call.
-  if (!object->IsString() || !cell.is_null()) return Handle<Code>::null();
-
-  const int argc = arguments().immediate();
-  StackArgumentsAccessor args(rsp, argc);
-
-  Label miss;
-  Label name_miss;
-  Label index_out_of_range;
-  Label* index_out_of_range_label = &index_out_of_range;
-  if (kind_ == Code::CALL_IC &&
-      (CallICBase::StringStubState::decode(extra_state()) ==
-       DEFAULT_STRING_STUB)) {
-    index_out_of_range_label = &miss;
-  }
-
-  HandlerFrontendHeader(object, holder, name, STRING_CHECK, &name_miss);
-
-  Register receiver = rax;
-  Register index = rdi;
-  Register scratch = rdx;
-  Register result = rax;
-  __ movq(receiver, args.GetReceiverOperand());
-  if (argc > 0) {
-    __ movq(index, args.GetArgumentOperand(1));
-  } else {
-    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
-  }
-
-  StringCharAtGenerator generator(receiver,
-                                  index,
-                                  scratch,
-                                  result,
-                                  &miss,  // When not a string.
-                                  &miss,  // When not a number.
-                                  index_out_of_range_label,
-                                  STRING_INDEX_IS_NUMBER);
-  generator.GenerateFast(masm());
-  __ ret((argc + 1) * kPointerSize);
-
-  StubRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm(), call_helper);
-
-  if (index_out_of_range.is_linked()) {
-    __ bind(&index_out_of_range);
-    __ LoadRoot(rax, Heap::kempty_stringRootIndex);
-    __ ret((argc + 1) * kPointerSize);
-  }
-  __ bind(&miss);
-  // Restore function name in rcx.
-  __ Move(rcx, name);
-  HandlerFrontendFooter(&name_miss);
-
-  // Return the generated code.
-  return GetCode(type, name);
-}
-
-
 Handle<Code> CallStubCompiler::CompileStringFromCharCodeCall(
     Handle<Object> object,
     Handle<JSObject> holder,