[stubs] Port LoadIndexedStringStub to CSA

src/builtins/builtins-handler.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/builtins/builtins-utils.h"
 #include "src/builtins/builtins.h"
 #include "src/code-stub-assembler.h"
 #include "src/ic/handler-compiler.h"
 #include "src/ic/ic.h"
 #include "src/ic/keyed-store-generic.h"
 
 namespace v8 {
 namespace internal {
 
+TF_BUILTIN(KeyedLoadIC_IndexedString, CodeStubAssembler) {
+  typedef LoadWithVectorDescriptor Descriptor;
+
+  Node* receiver = Parameter(Descriptor::kReceiver);
+  Node* index = Parameter(Descriptor::kName);
+  Node* slot = Parameter(Descriptor::kSlot);
+  Node* vector = Parameter(Descriptor::kVector);
+  Node* context = Parameter(Descriptor::kContext);
+
+  Label miss(this);
+
+  Node* index_intptr = TryToIntptr(index, &miss);
+  Node* length = SmiUntag(LoadStringLength(receiver));
+  GotoIf(UintPtrGreaterThanOrEqual(index_intptr, length), &miss);
+
+  Node* code = StringCharCodeAt(receiver, index_intptr, INTPTR_PARAMETERS);
+  Node* result = StringFromCharCode(code);
+  Return(result);
+
+  Bind(&miss);
+  TailCallRuntime(Runtime::kKeyedLoadIC_Miss, context, receiver, index, slot,
+                  vector);
+}
+
 TF_BUILTIN(KeyedLoadIC_Miss, CodeStubAssembler) {
   typedef LoadWithVectorDescriptor Descriptor;
 
   Node* receiver = Parameter(Descriptor::kReceiver);
   Node* name = Parameter(Descriptor::kName);
   Node* slot = Parameter(Descriptor::kSlot);
   Node* vector = Parameter(Descriptor::kVector);
   Node* context = Parameter(Descriptor::kContext);
 
   TailCallRuntime(Runtime::kKeyedLoadIC_Miss, context, receiver, name, slot,
@@ skipping 184 matching lines @@
   TailCallRuntime(Runtime::kStoreIC_Miss, context, value, slot, vector,
                   receiver, name);
 }
 
 void Builtins::Generate_StoreIC_Setter_ForDeopt(MacroAssembler* masm) {
   NamedStoreHandlerCompiler::GenerateStoreViaSetterForDeopt(masm);
 }
 
 }  // namespace internal
 }  // namespace v8