Fix multi-isolate build:

src/ia32/macro-assembler-ia32.h

 // Copyright 2010 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 38 matching lines @@
 // distinguish memory operands from other operands on ia32.
 typedef Operand MemOperand;
 
 // Forward declaration.
 class JumpTarget;
 class PostCallGenerator;
 
 // MacroAssembler implements a collection of frequently used macros.
 class MacroAssembler: public Assembler {
  public:
-  MacroAssembler(void* buffer, int size);
+  // The isolate parameter can be NULL if the macro assembler should
+  // not use isolate-dependent functionality. In this case, it's the
+  // responsibility of the caller to never invoke such function on the
+  // macro assembler.
+  MacroAssembler(Isolate* isolate, void* buffer, int size);
 
   // ---------------------------------------------------------------------------
   // GC Support
 
   // For page containing |object| mark region covering |addr| dirty.
   // RecordWriteHelper only works if the object is not in new
   // space.
   void RecordWriteHelper(Register object,
                          Register addr,
                          Register scratch);
@@ skipping 503 matching lines @@
   void CallSelf() {
     Handle<Code> self(reinterpret_cast<Code**>(CodeObject().location()));
     call(self, RelocInfo::CODE_TARGET);
   }
 
   // Move if the registers are not identical.
   void Move(Register target, Register source);
 
   void Move(Register target, Handle<Object> value);
 
-  Handle<Object> CodeObject() { return code_object_; }
+  Handle<Object> CodeObject() {
+    ASSERT(!code_object_.is_null());
+    return code_object_;
+  }
 
 
   // ---------------------------------------------------------------------------
   // StatsCounter support
 
   void SetCounter(StatsCounter* counter, int value);
   void IncrementCounter(StatsCounter* counter, int value);
   void DecrementCounter(StatsCounter* counter, int value);
   void IncrementCounter(Condition cc, StatsCounter* counter, int value);
   void DecrementCounter(Condition cc, StatsCounter* counter, int value);
@@ skipping 197 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_