Refactor the IL for object allocation with type arguments.

runtime/vm/intermediate_language_arm.cc

Index: runtime/vm/intermediate_language_arm.cc
===================================================================
--- runtime/vm/intermediate_language_arm.cc	(revision 22932)
+++ runtime/vm/intermediate_language_arm.cc	(working copy)
@@ -1617,12 +1617,10 @@
   // instantiated from null becomes a vector of dynamic, then use null as
   // the type arguments.
   Label type_arguments_instantiated;
-  const intptr_t len = type_arguments().Length();
-  if (type_arguments().IsRawInstantiatedRaw(len)) {
-    __ CompareImmediate(instantiator_reg,
-                        reinterpret_cast<intptr_t>(Object::null()));
-    __ b(&type_arguments_instantiated, EQ);
-  }
+  ASSERT(type_arguments().IsRawInstantiatedRaw(type_arguments().Length()));

[regis, 2013/05/21 16:39:36]

Do I understand correctly that you only use this
ExtractConstructorTypeArgumentsInstr any more in the case where the
uninstantiated type arguments is set to null if the instantiator is null? A
comment would be useful.

+  __ CompareImmediate(instantiator_reg,
+                      reinterpret_cast<intptr_t>(Object::null()));
+  __ b(&type_arguments_instantiated, EQ);
   // Instantiate non-null type arguments.
   // In the non-factory case, we rely on the allocation stub to
   // instantiate the type arguments.
@@ -1660,18 +1658,16 @@
   // If the instantiator is null and if the type argument vector
   // instantiated from null becomes a vector of dynamic, then use null as
   // the type arguments and do not pass the instantiator.
-  const intptr_t len = type_arguments().Length();
-  if (type_arguments().IsRawInstantiatedRaw(len)) {
-    Label instantiator_not_null;
-    __ CompareImmediate(instantiator_reg,
-                        reinterpret_cast<intptr_t>(Object::null()));
-    __ b(&instantiator_not_null, NE);
-    // Null was used in VisitExtractConstructorTypeArguments as the
-    // instantiated type arguments, no proper instantiator needed.
-    __ LoadImmediate(instantiator_reg,
-                     Smi::RawValue(StubCode::kNoInstantiator));
-    __ Bind(&instantiator_not_null);
-  }
+  ASSERT(type_arguments().IsRawInstantiatedRaw(type_arguments().Length()));
+  Label instantiator_not_null;
+  __ CompareImmediate(instantiator_reg,
+                      reinterpret_cast<intptr_t>(Object::null()));
+  __ b(&instantiator_not_null, NE);
+  // Null was used in VisitExtractConstructorTypeArguments as the
+  // instantiated type arguments, no proper instantiator needed.
+  __ LoadImmediate(instantiator_reg,
+                   Smi::RawValue(StubCode::kNoInstantiator));
+  __ Bind(&instantiator_not_null);
   // instantiator_reg: instantiator or kNoInstantiator.
 }