Port string stub for keyed loads to x64 and ARM (http://code.google.com/p/v8/...

src/x64/ic-x64.cc

 // Copyright 2010 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 506 matching lines @@
 }
 
 
 void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rsp[0] : return address
   //  -- rsp[8] : name
   //  -- rsp[16] : receiver
   // -----------------------------------
 
-  GenerateGeneric(masm);
+  Label miss, index_ok;
+
+  // Check that the receiver isn't a smi.
+  __ movq(rcx, Operand(rsp, 2 * kPointerSize));
+  __ JumpIfSmi(rcx, &miss);
+
+  // Check that the receiver is a string.
+  Condition is_string = masm->IsObjectStringType(rcx, rax, rbx);
+  __ j(NegateCondition(is_string), &miss);
+
+  // Check if key is a smi or a heap number.
+  __ movq(rax, Operand(rsp, kPointerSize));
+  __ JumpIfSmi(rax, &index_ok);
+  __ CheckMap(rax, Factory::heap_number_map(), &miss, false);
+
+  __ bind(&index_ok);
+  // Duplicate receiver and key since they are expected on the stack after
+  // the KeyedLoadIC call.
+  __ pop(rbx);  // return address
+  __ push(rcx);  // receiver
+  __ push(rax);  // key
+  __ push(rbx);  // return address
+  __ InvokeBuiltin(Builtins::STRING_CHAR_AT, JUMP_FUNCTION);
+
+  __ bind(&miss);
+  GenerateMiss(masm);
 }
 
 
 void KeyedLoadIC::GenerateExternalArray(MacroAssembler* masm,
                                         ExternalArrayType array_type) {
   // ----------- S t a t e -------------
   //  -- rsp[0] : return address
   //  -- rsp[8] : name
   //  -- rsp[16] : receiver
   // -----------------------------------
@@ skipping 1010 matching lines @@
   __ bind(&miss);
 
   GenerateMiss(masm);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal