Revert r4444 "Inline fast cases in string keyed load IC."

src/ia32/ic-ia32.cc

 // Copyright 2006-2008 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 473 matching lines @@
          (1 << String::kArrayIndexValueBits));
   __ bind(&index_string);
   __ and_(ebx, String::kArrayIndexHashMask);
   __ shr(ebx, String::kHashShift);
   __ jmp(&index_int);
 }
 
 
 void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
   // ----------- S t a t e -------------
-  //  -- eax    : key (index)
+  //  -- eax    : key
   //  -- edx    : receiver
   //  -- esp[0] : return address
   // -----------------------------------
-  Label miss;
-  Label not_positive_smi;
-  Label slow_char_code;
-  Label got_char_code;
+  Label miss, index_ok;
 
-  Register receiver = edx;
-  Register index = eax;
-  Register code = ebx;
-  Register scratch = ecx;
+  // Pop return address.
+  // Performing the load early is better in the common case.
+  __ pop(ebx);
 
-  StringHelper::GenerateFastCharCodeAt(masm,
-                                       receiver,
-                                       index,
-                                       scratch,
-                                       code,
-                                       &miss,  // When not a string.
-                                       &not_positive_smi,
-                                       &slow_char_code);
-  // If we didn't bail out, code register contains smi tagged char
-  // code.
-  __ bind(&got_char_code);
-  StringHelper::GenerateCharFromCode(masm, code, eax, JUMP_FUNCTION);
-#ifdef DEBUG
-  __ Abort("Unexpected fall-through from char from code tail call");
-#endif
+  __ test(edx, Immediate(kSmiTagMask));
+  __ j(zero, &miss);
+  __ mov(ecx, FieldOperand(edx, HeapObject::kMapOffset));
+  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
+  __ test(ecx, Immediate(kIsNotStringMask));
+  __ j(not_zero, &miss);
 
   // Check if key is a smi or a heap number.
-  __ bind(&not_positive_smi);
-  ASSERT(kSmiTag == 0);
-  __ test(index, Immediate(kSmiTagMask));
-  __ j(zero, &slow_char_code);
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &index_ok);
   __ mov(ecx, FieldOperand(eax, HeapObject::kMapOffset));
   __ cmp(ecx, Factory::heap_number_map());
   __ j(not_equal, &miss);
 
-  // Push receiver and key on the stack (now that we know they are a
-  // string and a number), and call runtime.
-  __ bind(&slow_char_code);
-  __ EnterInternalFrame();
-  __ push(receiver);
-  __ push(index);
-  __ CallRuntime(Runtime::kStringCharCodeAt, 1);
-  ASSERT(!code.is(eax));
-  __ mov(code, eax);
-  __ LeaveInternalFrame();
-  __ jmp(&got_char_code);
+  __ bind(&index_ok);
+  // Push receiver and key on the stack, and make a tail call.
+  __ push(edx);  // receiver
+  __ push(eax);  // key
+  __ push(ebx);  // return address
+  __ InvokeBuiltin(Builtins::STRING_CHAR_AT, JUMP_FUNCTION);
 
   __ bind(&miss);
+  __ push(ebx);
   GenerateMiss(masm);
 }
 
 
 void KeyedLoadIC::GenerateExternalArray(MacroAssembler* masm,
                                         ExternalArrayType array_type) {
   // ----------- S t a t e -------------
   //  -- eax    : key
   //  -- edx    : receiver
   //  -- esp[0] : return address
@@ skipping 1068 matching lines @@
 
   // Do tail-call to runtime routine.
   ExternalReference ref = ExternalReference(IC_Utility(kKeyedStoreIC_Miss));
   __ TailCallExternalReference(ref, 3, 1);
 }
 
 #undef __
 
 
 } }  // namespace v8::internal