Further improve and simplify IL for building constructor type arguments.

runtime/vm/intermediate_language_arm.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_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 1592 matching lines @@
 
 
 void ExtractConstructorTypeArgumentsInstr::EmitNativeCode(
     FlowGraphCompiler* compiler) {
   Register instantiator_reg = locs()->in(0).reg();
   Register result_reg = locs()->out().reg();
   ASSERT(instantiator_reg == result_reg);
 
   // instantiator_reg is the instantiator type argument vector, i.e. an
   // AbstractTypeArguments object (or null).
-  if (!type_arguments().IsUninstantiatedIdentity() &&
-      !type_arguments().CanShareInstantiatorTypeArguments(
-          instantiator_class())) {
-    // 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.
-    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);
-    }
-    // Instantiate non-null type arguments.
-    // In the non-factory case, we rely on the allocation stub to
-    // instantiate the type arguments.
-    __ LoadObject(result_reg, type_arguments());
-    // result_reg: uninstantiated type arguments.
-    __ Bind(&type_arguments_instantiated);
+  ASSERT(!type_arguments().IsUninstantiatedIdentity() &&
+         !type_arguments().CanShareInstantiatorTypeArguments(
+             instantiator_class()));
+  // 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.
+  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(instantiator_reg == result_reg);
+  // Instantiate non-null type arguments.
+  // In the non-factory case, we rely on the allocation stub to
+  // instantiate the type arguments.
+  __ LoadObject(result_reg, type_arguments());
+  // result_reg: uninstantiated type arguments.
+  __ Bind(&type_arguments_instantiated);
+
   // result_reg: uninstantiated or instantiated type arguments.
 }
 
 
 LocationSummary*
 ExtractConstructorInstantiatorInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_in(0, Location::RequiresRegister());
   locs->set_out(Location::SameAsFirstInput());
   return locs;
 }
 
 
 void ExtractConstructorInstantiatorInstr::EmitNativeCode(
     FlowGraphCompiler* compiler) {
   Register instantiator_reg = locs()->in(0).reg();
   ASSERT(locs()->out().reg() == instantiator_reg);
 
   // instantiator_reg is the instantiator AbstractTypeArguments object
   // (or null).
-  if (type_arguments().IsUninstantiatedIdentity() ||
-      type_arguments().CanShareInstantiatorTypeArguments(
-          instantiator_class())) {
-    // The instantiator was used in VisitExtractConstructorTypeArguments as the
+  ASSERT(!type_arguments().IsUninstantiatedIdentity() &&
+         !type_arguments().CanShareInstantiatorTypeArguments(
+             instantiator_class()));
+
+  // 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,

[Kevin Millikin (Google), 2013/05/21 11:06:05]

Yeah, this is kind of broken.

                      Smi::RawValue(StubCode::kNoInstantiator));
-  } else {
-    // 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);
-    }
+    __ Bind(&instantiator_not_null);
   }
   // instantiator_reg: instantiator or kNoInstantiator.
 }
 
 
 LocationSummary* AllocateContextInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 0;
   const intptr_t kNumTemps = 1;
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
@@ skipping 1182 matching lines @@
   compiler->GenerateCall(token_pos(),
                          &label,
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM