Use Object::null_object() instead of Object::ZoneHandle() when a null object

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 711 matching lines @@
 void NativeCallInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   ASSERT(locs()->temp(0).reg() == RAX);
   ASSERT(locs()->temp(1).reg() == RBX);
   ASSERT(locs()->temp(2).reg() == R10);
   Register result = locs()->out(0).reg();
   const intptr_t argc_tag = NativeArguments::ComputeArgcTag(function());
   const bool is_leaf_call =
     (argc_tag & NativeArguments::AutoSetupScopeMask()) == 0;
 
   // Push the result place holder initialized to NULL.
-  __ PushObject(Object::ZoneHandle(), PP);
+  __ PushObject(Object::null_object(), PP);
   // Pass a pointer to the first argument in RAX.
   if (!function().HasOptionalParameters()) {
     __ leaq(RAX, Address(RBP, (kParamEndSlotFromFp +
                                function().NumParameters()) * kWordSize));
   } else {
     __ leaq(RAX,
             Address(RBP, kFirstLocalSlotFromFp * kWordSize));
   }
   __ LoadImmediate(
       RBX, Immediate(reinterpret_cast<uword>(native_c_function())), PP);
@@ skipping 1251 matching lines @@
   ASSERT(locs()->in(1).reg() == kLengthReg);
 
   Label slow_path, done;
   if (num_elements()->BindsToConstant() &&
       num_elements()->BoundConstant().IsSmi()) {
     const intptr_t length = Smi::Cast(num_elements()->BoundConstant()).Value();
     if ((length >= 0) && (length <= Array::kMaxElements)) {
       Label slow_path, done;
       InlineArrayAllocation(compiler, length, &slow_path, &done);
       __ Bind(&slow_path);
-      __ PushObject(Object::ZoneHandle(), PP);  // Make room for the result.
+      __ PushObject(Object::null_object(), PP);  // Make room for the result.
       __ pushq(kLengthReg);
       __ pushq(kElemTypeReg);
       compiler->GenerateRuntimeCall(token_pos(),
                                     deopt_id(),
                                     kAllocateArrayRuntimeEntry,
                                     2,
                                     locs());
       __ Drop(2);
       __ popq(kResultReg);
       __ Bind(&done);
@@ skipping 264 matching lines @@
   return locs;
 }
 
 
 void InstantiateTypeInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register instantiator_reg = locs()->in(0).reg();
   Register result_reg = locs()->out(0).reg();
 
   // 'instantiator_reg' is the instantiator TypeArguments object (or null).
   // A runtime call to instantiate the type is required.
-  __ PushObject(Object::ZoneHandle(), PP);  // Make room for the result.
+  __ PushObject(Object::null_object(), PP);  // Make room for the result.
   __ PushObject(type(), PP);
   __ pushq(instantiator_reg);  // Push instantiator type arguments.
   compiler->GenerateRuntimeCall(token_pos(),
                                 deopt_id(),
                                 kInstantiateTypeRuntimeEntry,
                                 2,
                                 locs());
   __ Drop(2);  // Drop instantiator and uninstantiated type.
   __ popq(result_reg);  // Pop instantiated type.
   ASSERT(instantiator_reg == result_reg);
@@ skipping 50 matching lines @@
   __ cmpq(RDX, Immediate(Smi::RawValue(StubCode::kNoInstantiator)));
   __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
   __ jmp(&slow_case, Assembler::kNearJump);
   __ Bind(&found);
   __ movq(RAX, Address(RDI, 1 * kWordSize));  // Cached instantiated args.
   __ jmp(&type_arguments_instantiated, Assembler::kNearJump);
 
   __ Bind(&slow_case);
   // Instantiate non-null type arguments.
   // A runtime call to instantiate the type arguments is required.
-  __ PushObject(Object::ZoneHandle(), PP);  // Make room for the result.
+  __ PushObject(Object::null_object(), PP);  // Make room for the result.
   __ PushObject(type_arguments(), PP);
   __ pushq(instantiator_reg);  // Push instantiator type arguments.
   compiler->GenerateRuntimeCall(token_pos(),
                                 deopt_id(),
                                 kInstantiateTypeArgumentsRuntimeEntry,
                                 2,
                                 locs());
   __ Drop(2);  // Drop instantiator and uninstantiated type arguments.
   __ popq(result_reg);  // Pop instantiated type arguments.
   __ Bind(&type_arguments_instantiated);
@@ skipping 35 matching lines @@
   locs->set_in(0, Location::RegisterLocation(RAX));
   locs->set_out(0, Location::RegisterLocation(RAX));
   return locs;
 }
 
 
 void CloneContextInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register context_value = locs()->in(0).reg();
   Register result = locs()->out(0).reg();
 
-  __ PushObject(Object::ZoneHandle(), PP);  // Make room for the result.
+  __ PushObject(Object::null_object(), PP);  // Make room for the result.
   __ pushq(context_value);
   compiler->GenerateRuntimeCall(token_pos(),
                                 deopt_id(),
                                 kCloneContextRuntimeEntry,
                                 1,
                                 locs());
   __ popq(result);  // Remove argument.
   __ popq(result);  // Get result (cloned context).
 }
 
@@ skipping 3414 matching lines @@
   __ movq(R10, Immediate(kInvalidObjectPointer));
   __ movq(RBX, Immediate(kInvalidObjectPointer));
 #endif
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64