First take on custom call generators.

src/ia32/macro-assembler-ia32.h

 // Copyright 2006-2009 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
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 class JumpTarget;
 
 // MacroAssembler implements a collection of frequently used macros.
 class MacroAssembler: public Assembler {
  public:
   MacroAssembler(void* buffer, int size);
 
   // ---------------------------------------------------------------------------
   // GC Support
 
+
+  void RecordWriteHelper(Register object,
+                         Register addr,
+                         Register scratch);
+
+  // Check if object is in new space.
+  // scratch can be object itself, but it will be clobbered.
+  void InNewSpace(Register object,
+                  Register scratch,
+                  Condition cc,  // equal for new space, not_equal otherwise.
+                  Label* branch);
+
   // Set the remembered set bit for [object+offset].
   // object is the object being stored into, value is the object being stored.
   // If offset is zero, then the scratch register contains the array index into
   // the elements array represented as a Smi.
   // All registers are clobbered by the operation.
   void RecordWrite(Register object,
                    int offset,
                    Register value,
                    Register scratch);
 
@@ skipping 506 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_