Fix ABI for API calls on ia32.

src/ia32/macro-assembler-ia32.h

 // Copyright 2011 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 540 matching lines @@
   // Calls a C function and cleans up the space for arguments allocated
   // by PrepareCallCFunction. The called function is not allowed to trigger a
   // garbage collection, since that might move the code and invalidate the
   // return address (unless this is somehow accounted for by the called
   // function).
   void CallCFunction(ExternalReference function, int num_arguments);
   void CallCFunction(Register function, int num_arguments);
 
   // Prepares stack to put arguments (aligns and so on). Reserves
   // space for return value if needed (assumes the return value is a handle).
-  // Uses callee-saved esi to restore stack state after call. Arguments must be
-  // stored in ApiParameterOperand(0), ApiParameterOperand(1) etc. Saves
-  // context (esi).
-  void PrepareCallApiFunction(int argc, Register scratch);
+  // Arguments must be stored in ApiParameterOperand(0), ApiParameterOperand(1)
+  // etc. Saves context (esi). If space was reserved for return value then
+  // stores the pointer to the reserved slot into esi.
+  void PrepareCallApiFunction(int argc);
 
   // Calls an API function. Allocates HandleScope, extracts
   // returned value from handle and propagates exceptions.
   // Clobbers ebx, edi and caller-save registers. Restores context.
   // On return removes stack_space * kPointerSize (GCed).
   MaybeObject* TryCallApiFunctionAndReturn(ApiFunction* function,
                                            int stack_space);
 
   // Jump to a runtime routine.
   void JumpToExternalReference(const ExternalReference& ext);
@@ skipping 212 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_