Apply Daniel's patch for array index strings.

src/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 194 matching lines @@
   StubCompiler::GenerateLoadMiss(masm, Code::LOAD_IC);
 }
 
 
 void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- esp[0] : return address
   //  -- esp[4] : name
   //  -- esp[8] : receiver
   // -----------------------------------
-  Label slow, fast, check_string;
+  Label slow, fast, check_string, index_int, index_string;
 
   __ mov(eax, (Operand(esp, kPointerSize)));
   __ mov(ecx, (Operand(esp, 2 * kPointerSize)));
 
   // Check that the object isn't a smi.
   __ test(ecx, Immediate(kSmiTagMask));
   __ j(zero, &slow, not_taken);
   // Check that the object is some kind of JS object EXCEPT JS Value type.
   // In the case that the object is a value-wrapper object,
   // we enter the runtime system to make sure that indexing
   // into string objects work as intended.
   ASSERT(JS_OBJECT_TYPE > JS_VALUE_TYPE);
   __ mov(edx, FieldOperand(ecx, HeapObject::kMapOffset));
   __ movzx_b(edx, FieldOperand(edx, Map::kInstanceTypeOffset));
   __ cmp(edx, JS_OBJECT_TYPE);
   __ j(less, &slow, not_taken);
   // Check that the key is a smi.
   __ test(eax, Immediate(kSmiTagMask));
   __ j(not_zero, &check_string, not_taken);
   __ sar(eax, kSmiTagSize);
   // Get the elements array of the object.
+  __ bind(&index_int);
   __ mov(ecx, FieldOperand(ecx, JSObject::kElementsOffset));
   // Check that the object is in fast mode (not dictionary).
   __ cmp(FieldOperand(ecx, HeapObject::kMapOffset),
          Immediate(Factory::hash_table_map()));
   __ j(equal, &slow, not_taken);
   // Check that the key (index) is within bounds.
   __ cmp(eax, FieldOperand(ecx, Array::kLengthOffset));
   __ j(below, &fast, taken);
   // Slow case: Load name and receiver from stack and jump to runtime.
   __ bind(&slow);
   __ IncrementCounter(&Counters::keyed_load_generic_slow, 1);
   KeyedLoadIC::Generate(masm, ExternalReference(Runtime::kKeyedGetProperty));
   // Check if the key is a symbol that is not an array index.
   __ bind(&check_string);
+  __ mov(ebx, FieldOperand(eax, String::kLengthOffset));
+  __ test(ebx, Immediate(String::kIsArrayIndexMask));
+  __ j(not_zero, &index_string, not_taken);
   __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
   __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
   __ test(ebx, Immediate(kIsSymbolMask));
-  __ j(zero, &slow, not_taken);
-  __ mov(ebx, FieldOperand(eax, String::kLengthOffset));
-  __ test(ebx, Immediate(String::kIsArrayIndexMask));
   __ j(not_zero, &slow, not_taken);
   // Probe the dictionary leaving result in ecx.
   GenerateDictionaryLoad(masm, &slow, ebx, ecx, edx, eax);
   __ mov(eax, Operand(ecx));
   __ IncrementCounter(&Counters::keyed_load_generic_symbol, 1);
   __ ret(0);
+  // Array index string: If short enough use cache in length/hash field (ebx).
+  __ bind(&index_string);
+  const int kLengthFieldLimit =
+      (String::kMaxCachedArrayIndexLength + 1) << String::kShortLengthShift;
+  __ cmp(ebx, kLengthFieldLimit);
+  __ j(above_equal, &slow);
+  __ mov(eax, Operand(ebx));
+  __ and_(eax, (1 << String::kShortLengthShift) - 1);
+  __ shr(eax, String::kLongLengthShift);
+  __ jmp(&index_int);
   // Fast case: Do the load.
   __ bind(&fast);
   __ mov(eax, Operand(ecx, eax, times_4, Array::kHeaderSize - kHeapObjectTag));
   __ cmp(Operand(eax), Immediate(Factory::the_hole_value()));
   // In case the loaded value is the_hole we have to consult GetProperty
   // to ensure the prototype chain is searched.
   __ j(equal, &slow, not_taken);
   __ IncrementCounter(&Counters::keyed_load_generic_smi, 1);
   __ ret(0);
 }
@@ skipping 496 matching lines @@
 
   // Do tail-call to runtime routine.
   __ TailCallRuntime(
       ExternalReference(IC_Utility(kSharedStoreIC_ExtendStorage)), 3);
 }
 
 #undef __
 
 
 } }  // namespace v8::internal