Inline array loads in loops directly in the code instead of always...

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 715 matching lines @@
   __ pop(ebx);
   __ push(eax);
   __ push(ecx);
   __ push(ebx);
 
   // Perform tail call to the entry.
   __ TailCallRuntime(f, 2);
 }
 
 
+void KeyedLoadIC::PatchInlinedMapCheck(Address address, Object* value) {
+  static const byte kTestEaxByte = 0xA9;
+  Address test_instruction_address = address + 4;  // 4 = stub address
+  // The keyed load has a fast inlined case if the IC call instruction
+  // is immediately followed by a test instruction.
+  if (*test_instruction_address == kTestEaxByte) {
+    // Fetch the offset from the call instruction to the map cmp
+    // instruction.  This offset is stored in the last 4 bytes of the
+    // 5 byte test instruction.
+    Address offset_address = test_instruction_address + 1;
+    int offset_value = *(reinterpret_cast<int*>(offset_address));
+    // Compute the map address.  The operand-immediate compare
+    // instruction is two bytes larger than a call instruction so we
+    // add 2 to get to the map address.
+    Address map_address = address + offset_value + 2;
+    // patch the map check.
+    (*(reinterpret_cast<Object**>(map_address))) = value;
+  }
+}
+
+
 // Defined in ic.cc.
 Object* KeyedLoadIC_Miss(Arguments args);
 
 
 void KeyedLoadIC::GenerateMiss(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- esp[0] : return address
   //  -- esp[4] : name
   //  -- esp[8] : receiver
   // -----------------------------------
@@ skipping 122 matching lines @@
 
   // Do tail-call to runtime routine.
   __ TailCallRuntime(
       ExternalReference(IC_Utility(kSharedStoreIC_ExtendStorage)), 3);
 }
 
 #undef __
 
 
 } }  // namespace v8::internal