Implement tracking and optimizations of packed arrays

src/ia32/ic-ia32.cc

 // Copyright 2012 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
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 //     * Redistributions in binary form must reproduce the above
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@@ skipping 871 matching lines @@
 
   __ bind(&transition_smi_elements);
   __ mov(ebx, FieldOperand(edx, HeapObject::kMapOffset));
 
   // Transition the array appropriately depending on the value type.
   __ CheckMap(eax,
               masm->isolate()->factory()->heap_number_map(),
               &non_double_value,
               DONT_DO_SMI_CHECK);
 
-  // Value is a double. Transition FAST_SMI_ONLY_ELEMENTS ->
-  // FAST_DOUBLE_ELEMENTS and complete the store.
-  __ LoadTransitionedArrayMapConditional(FAST_SMI_ONLY_ELEMENTS,
+  // Value is a double. Transition FAST_*_SMI_ELEMENTS -> FAST_*_DOUBLE_ELEMENTS

[Jakob Kummerow, 2012/05/13 21:55:27]

The comment says that FAST_*_SMI_ELEMENTS are transitioned, but
FAST_HOLEY_SMI_ELEMENTS actually jump to &slow. Is that intentional?

[danno, 2012/05/22 11:05:21]

For now, yes. When Toon finishes his changes, all cases will be handled here. 
On 2012/05/13 21:55:27, Jakob wrote:

+  // and complete the store.
+  __ LoadTransitionedArrayMapConditional(FAST_SMI_ELEMENTS,
                                          FAST_DOUBLE_ELEMENTS,
                                          ebx,
                                          edi,
                                          &slow);
   ElementsTransitionGenerator::GenerateSmiOnlyToDouble(masm, &slow);
   __ mov(ebx, FieldOperand(edx, JSObject::kElementsOffset));
   __ jmp(&fast_double_without_map_check);
 
   __ bind(&non_double_value);
   // Value is not a double, FAST_SMI_ONLY_ELEMENTS -> FAST_ELEMENTS

[Jakob Kummerow, 2012/05/13 21:55:27]

nit: s/ONLY_// or s/ONLY_/*_/.
Also, HOLEY elements again aren't handled in the fast path. Intentional?

[danno, 2012/05/22 11:05:21]

Done.

-  __ LoadTransitionedArrayMapConditional(FAST_SMI_ONLY_ELEMENTS,
+  __ LoadTransitionedArrayMapConditional(FAST_SMI_ELEMENTS,
                                          FAST_ELEMENTS,
                                          ebx,
                                          edi,
                                          &slow);
-  ElementsTransitionGenerator::GenerateSmiOnlyToObject(masm);
+  ElementsTransitionGenerator::GenerateMapChangeElementTransition(masm);
   __ mov(ebx, FieldOperand(edx, JSObject::kElementsOffset));
   __ jmp(&finish_object_store);
 
   __ bind(&transition_double_elements);
   // Elements are FAST_DOUBLE_ELEMENTS, but value is an Object that's not a
   // HeapNumber. Make sure that the receiver is a Array with FAST_ELEMENTS and
   // transition array from FAST_DOUBLE_ELEMENTS to FAST_ELEMENTS
   __ mov(ebx, FieldOperand(edx, HeapObject::kMapOffset));
   __ LoadTransitionedArrayMapConditional(FAST_DOUBLE_ELEMENTS,
                                          FAST_ELEMENTS,
@@ skipping 844 matching lines @@
   Condition cc = (check == ENABLE_INLINED_SMI_CHECK)
       ? (*jmp_address == Assembler::kJncShortOpcode ? not_zero : zero)
       : (*jmp_address == Assembler::kJnzShortOpcode ? not_carry : carry);
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32