Additional minor cleanup regarding CallWrapper: Use the null object pattern.

src/arm/macro-assembler-arm.cc

 // 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 868 matching lines @@
   }
 }
 
 
 void MacroAssembler::InvokePrologue(const ParameterCount& expected,
                                     const ParameterCount& actual,
                                     Handle<Code> code_constant,
                                     Register code_reg,
                                     Label* done,
                                     InvokeFlag flag,
-                                    CallWrapper* call_wrapper) {
+                                    const CallWrapper& call_wrapper) {
   bool definitely_matches = false;
   Label regular_invoke;
 
   // Check whether the expected and actual arguments count match. If not,
   // setup registers according to contract with ArgumentsAdaptorTrampoline:
   //  r0: actual arguments count
   //  r1: function (passed through to callee)
   //  r2: expected arguments count
   //  r3: callee code entry
 
@@ skipping 34 matching lines @@
 
   if (!definitely_matches) {
     if (!code_constant.is_null()) {
       mov(r3, Operand(code_constant));
       add(r3, r3, Operand(Code::kHeaderSize - kHeapObjectTag));
     }
 
     Handle<Code> adaptor =
         isolate()->builtins()->ArgumentsAdaptorTrampoline();
     if (flag == CALL_FUNCTION) {
-      if (call_wrapper != NULL) {
-        call_wrapper->BeforeCall(CallSize(adaptor, RelocInfo::CODE_TARGET));
-      }
+      call_wrapper.BeforeCall(CallSize(adaptor, RelocInfo::CODE_TARGET));
       Call(adaptor, RelocInfo::CODE_TARGET);
-      if (call_wrapper != NULL) call_wrapper->AfterCall();
+      call_wrapper.AfterCall();
       b(done);
     } else {
       Jump(adaptor, RelocInfo::CODE_TARGET);
     }
     bind(&regular_invoke);
   }
 }
 
 
 void MacroAssembler::InvokeCode(Register code,
                                 const ParameterCount& expected,
                                 const ParameterCount& actual,
                                 InvokeFlag flag,
-                                CallWrapper* call_wrapper) {
+                                const CallWrapper& call_wrapper) {
   Label done;
 
   InvokePrologue(expected, actual, Handle<Code>::null(), code, &done, flag,
                  call_wrapper);
   if (flag == CALL_FUNCTION) {
-    if (call_wrapper != NULL) call_wrapper->BeforeCall(CallSize(code));
+    call_wrapper.BeforeCall(CallSize(code));
     Call(code);
-    if (call_wrapper != NULL) call_wrapper->AfterCall();
+    call_wrapper.AfterCall();
   } else {
     ASSERT(flag == JUMP_FUNCTION);
     Jump(code);
   }
 
   // Continue here if InvokePrologue does handle the invocation due to
   // mismatched parameter counts.
   bind(&done);
 }
 
@@ skipping 14 matching lines @@
 
   // Continue here if InvokePrologue does handle the invocation due to
   // mismatched parameter counts.
   bind(&done);
 }
 
 
 void MacroAssembler::InvokeFunction(Register fun,
                                     const ParameterCount& actual,
                                     InvokeFlag flag,
-                                    CallWrapper* call_wrapper) {
+                                    const CallWrapper& call_wrapper) {
   // Contract with called JS functions requires that function is passed in r1.
   ASSERT(fun.is(r1));
 
   Register expected_reg = r2;
   Register code_reg = r3;
 
   ldr(code_reg, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
   ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
   ldr(expected_reg,
       FieldMemOperand(code_reg,
@@ skipping 1291 matching lines @@
   ASSERT((reinterpret_cast<intptr_t>(builtin.address()) & 1) == 1);
 #endif
   mov(r1, Operand(builtin));
   CEntryStub stub(1);
   return TryTailCallStub(&stub);
 }
 
 
 void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id,
                                    InvokeFlag flag,
-                                   CallWrapper* call_wrapper) {
+                                   const CallWrapper& call_wrapper) {
   GetBuiltinEntry(r2, id);
   if (flag == CALL_FUNCTION) {
-    if (call_wrapper != NULL) call_wrapper->BeforeCall(CallSize(r2));
+    call_wrapper.BeforeCall(CallSize(r2));
     Call(r2);
-    if (call_wrapper != NULL) call_wrapper->AfterCall();
+    call_wrapper.AfterCall();
   } else {
     ASSERT(flag == JUMP_FUNCTION);
     Jump(r2);
   }
 }
 
 
 void MacroAssembler::GetBuiltinFunction(Register target,
                                         Builtins::JavaScript id) {
   // Load the builtins object into target register.
@@ skipping 721 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM