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

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
===================================================================
--- runtime/vm/intermediate_language_mips.cc	(revision 37955)
+++ runtime/vm/intermediate_language_mips.cc	(working copy)
@@ -868,7 +868,7 @@
   Register result = locs()->out(0).reg();
 
   // Push the result place holder initialized to NULL.
-  __ PushObject(Object::ZoneHandle());
+  __ PushObject(Object::null_object());
   // Pass a pointer to the first argument in A2.
   if (!function().HasOptionalParameters()) {
     __ AddImmediate(A2, FP, (kParamEndSlotFromFp +
@@ -2095,7 +2095,7 @@
       Label slow_path, done;
       InlineArrayAllocation(compiler, length, &slow_path, &done);
       __ Bind(&slow_path);
-      __ PushObject(Object::ZoneHandle());  // Make room for the result.
+      __ PushObject(Object::null_object());  // Make room for the result.
       __ Push(kLengthReg);  // length.
       __ Push(kElemTypeReg);
       compiler->GenerateRuntimeCall(token_pos(),
@@ -2272,7 +2272,7 @@
   // 'instantiator_reg' is the instantiator TypeArguments object (or null).
   // A runtime call to instantiate the type is required.
   __ addiu(SP, SP, Immediate(-3 * kWordSize));
-  __ LoadObject(TMP, Object::ZoneHandle());
+  __ LoadObject(TMP, Object::null_object());
   __ sw(TMP, Address(SP, 2 * kWordSize));  // Make room for the result.
   __ LoadObject(TMP, type());
   __ sw(TMP, Address(SP, 1 * kWordSize));
@@ -2346,7 +2346,7 @@
   // Instantiate non-null type arguments.
   // A runtime call to instantiate the type arguments is required.
   __ addiu(SP, SP, Immediate(-3 * kWordSize));
-  __ LoadObject(TMP, Object::ZoneHandle());
+  __ LoadObject(TMP, Object::null_object());
   __ sw(TMP, Address(SP, 2 * kWordSize));  // Make room for the result.
   __ LoadObject(TMP, type_arguments());
   __ sw(TMP, Address(SP, 1 * kWordSize));
@@ -2412,7 +2412,7 @@
   __ TraceSimMsg("CloneContextInstr");
 
   __ addiu(SP, SP, Immediate(-2 * kWordSize));
-  __ LoadObject(TMP, Object::ZoneHandle());  // Make room for the result.
+  __ LoadObject(TMP, Object::null_object());  // Make room for the result.
   __ sw(TMP, Address(SP, 1 * kWordSize));
   __ sw(context_value, Address(SP, 0 * kWordSize));