Cardmarking writebarrier.

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 284 matching lines @@
   StubCompiler::GenerateLoadMiss(masm, Code::LOAD_IC);
 }
 
 
 void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- eax    : key
   //  -- edx    : receiver
   //  -- esp[0] : return address
   // -----------------------------------
-  Label slow, check_string, index_int, index_string;
+  Label slow, check_string, index_smi, index_string;
   Label check_pixel_array, probe_dictionary;
   Label check_number_dictionary;
 
   // Check that the object isn't a smi.
   __ test(edx, Immediate(kSmiTagMask));
   __ j(zero, &slow, not_taken);
 
   // Get the map of the receiver.
   __ mov(ecx, FieldOperand(edx, HeapObject::kMapOffset));
 
   // Check bit field.
   __ movzx_b(ebx, FieldOperand(ecx, Map::kBitFieldOffset));
   __ test(ebx, Immediate(kSlowCaseBitFieldMask));
   __ j(not_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);
   __ CmpInstanceType(ecx, JS_OBJECT_TYPE);
   __ j(below, &slow, not_taken);
   // Check that the key is a smi.
   __ test(eax, Immediate(kSmiTagMask));
   __ j(not_zero, &check_string, not_taken);
-  __ mov(ebx, eax);
-  __ SmiUntag(ebx);
   // Get the elements array of the object.
-  __ bind(&index_int);
+  __ bind(&index_smi);
   __ mov(ecx, FieldOperand(edx, JSObject::kElementsOffset));
   // Check that the object is in fast mode (not dictionary).
   __ CheckMap(ecx, Factory::fixed_array_map(), &check_pixel_array, true);
   // Check that the key (index) is within bounds.
-  __ cmp(ebx, FieldOperand(ecx, FixedArray::kLengthOffset));
+  __ cmp(eax, FieldOperand(ecx, FixedArray::kLengthOffset));
   __ j(above_equal, &slow);
   // Fast case: Do the load.
-  __ mov(ecx, FieldOperand(ecx, ebx, times_4, FixedArray::kHeaderSize));
+  ASSERT((kPointerSize == 4) && (kSmiTagSize == 1) && (kSmiTag == 0));
+  __ mov(ecx, FieldOperand(ecx, eax, times_2, FixedArray::kHeaderSize));
   __ cmp(Operand(ecx), 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);
   __ mov(eax, ecx);
   __ IncrementCounter(&Counters::keyed_load_generic_smi, 1);
   __ ret(0);
 
   __ bind(&check_pixel_array);
   // Check whether the elements is a pixel array.
   // edx: receiver
-  // ebx: untagged index
   // eax: key
   // ecx: elements
+  __ mov(ebx, eax);
+  __ SmiUntag(ebx);
   __ CheckMap(ecx, Factory::pixel_array_map(), &check_number_dictionary, true);
   __ cmp(ebx, FieldOperand(ecx, PixelArray::kLengthOffset));
   __ j(above_equal, &slow);
   __ mov(eax, FieldOperand(ecx, PixelArray::kExternalPointerOffset));
   __ movzx_b(eax, Operand(eax, ebx, times_1, 0));
   __ SmiTag(eax);
   __ ret(0);
 
   __ bind(&check_number_dictionary);
   // Check whether the elements is a number dictionary.
@@ skipping 110 matching lines @@
   __ IncrementCounter(&Counters::keyed_load_generic_symbol, 1);
   __ ret(0);
 
   // If the hash field contains an array index pick it out. The assert checks
   // that the constants for the maximum number of digits for an array index
   // cached in the hash field and the number of bits reserved for it does not
   // conflict.
   ASSERT(TenToThe(String::kMaxCachedArrayIndexLength) <
          (1 << String::kArrayIndexValueBits));
   __ bind(&index_string);
-  __ and_(ebx, String::kArrayIndexHashMask);
-  __ shr(ebx, String::kHashShift);
-  __ jmp(&index_int);
+  // We want the smi-tagged index in eax.  kArrayIndexValueMask has zeros in
+  // the low kHashShift bits.
+  ASSERT(String::kHashShift >= kSmiTagSize);
+  __ and_(ebx, String::kArrayIndexValueMask);
+  __ shr(ebx, String::kHashShift - kSmiTagSize);
+  __ mov(eax, ebx);
+  __ jmp(&index_smi);
 }
 
 
 void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- eax    : key (index)
   //  -- edx    : receiver
   //  -- esp[0] : return address
   // -----------------------------------
   Label miss;
@@ skipping 284 matching lines @@
   __ CmpInstanceType(edi, FIRST_JS_OBJECT_TYPE);
   __ j(below, &slow, not_taken);
 
   // Object case: Check key against length in the elements array.
   // eax: value
   // edx: JSObject
   // ecx: key (a smi)
   __ mov(edi, FieldOperand(edx, JSObject::kElementsOffset));
   // Check that the object is in fast mode (not dictionary).
   __ CheckMap(edi, Factory::fixed_array_map(), &check_pixel_array, true);
-  __ mov(ebx, Operand(ecx));
-  __ SmiUntag(ebx);
-  __ cmp(ebx, FieldOperand(edi, Array::kLengthOffset));
+  __ cmp(ecx, FieldOperand(edi, FixedArray::kLengthOffset));
   __ j(below, &fast, taken);
 
   // Slow case: call runtime.
   __ bind(&slow);
   GenerateRuntimeSetProperty(masm);
 
   // Check whether the elements is a pixel array.
   __ bind(&check_pixel_array);
   // eax: value
-  // ecx: key
+  // ecx: key (a smi)
   // edx: receiver
   // edi: elements array
   __ CheckMap(edi, Factory::pixel_array_map(), &slow, true);
   // Check that the value is a smi. If a conversion is needed call into the
   // runtime to convert and clamp.
   __ test(eax, Immediate(kSmiTagMask));
   __ j(not_zero, &slow);
   __ mov(ebx, ecx);
   __ SmiUntag(ebx);
   __ cmp(ebx, FieldOperand(edi, PixelArray::kLengthOffset));
@@ skipping 15 matching lines @@
   // Extra capacity case: Check if there is extra capacity to
   // perform the store and update the length. Used for adding one
   // element to the array by writing to array[array.length].
   __ bind(&extra);
   // eax: value
   // edx: receiver, a JSArray
   // ecx: key, a smi.
   // edi: receiver->elements, a FixedArray
   // flags: compare (ecx, edx.length())
   __ j(not_equal, &slow, not_taken);  // do not leave holes in the array
-  __ mov(ebx, ecx);
-  __ SmiUntag(ebx);  // untag
-  __ cmp(ebx, FieldOperand(edi, Array::kLengthOffset));
+  __ cmp(ecx, FieldOperand(edi, FixedArray::kLengthOffset));
   __ j(above_equal, &slow, not_taken);
   // Add 1 to receiver->length, and go to fast array write.
   __ add(FieldOperand(edx, JSArray::kLengthOffset),
          Immediate(1 << kSmiTagSize));
   __ jmp(&fast);
 
   // Array case: Get the length and the elements array from the JS
   // array. Check that the array is in fast mode; if it is the
   // length is always a smi.
   __ bind(&array);
@@ skipping 782 matching lines @@
 
   // Do tail-call to runtime routine.
   ExternalReference ref = ExternalReference(IC_Utility(kKeyedStoreIC_Miss));
   __ TailCallExternalReference(ref, 3, 1);
 }
 
 #undef __
 
 
 } }  // namespace v8::internal