Make HForeignCode 'isAllocation' property available to optimization

pkg/compiler/lib/src/ssa/nodes.dart

 // Copyright (c) 2012, 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.
 
 part of ssa;
 
 abstract class HVisitor<R> {
   R visitAdd(HAdd node);
   R visitAwait(HAwait node);
   R visitBitAnd(HBitAnd node);
@@ skipping 824 matching lines @@
    * A pure instruction is an instruction that does not have any side
    * effect, nor any dependency. They can be moved anywhere in the
    * graph.
    */
   bool isPure() {
     return !sideEffects.hasSideEffects()
         && !sideEffects.dependsOnSomething()
         && !canThrow();
   }
 
+  /// An instruction is an 'allocation' is it is the sole alias for an object.
+  /// This applies to to instructions that allocate new objects and can be
+  /// extended to methods that return other allocations without escaping them.
+  bool get isAllocation => false;
+
   /// Overridden by [HCheck] to return the actual non-[HCheck]
   /// instruction it checks against.
   HInstruction nonCheck() => this;
 
   /// Can this node throw an exception?
   bool canThrow() => false;
 
   /// Does this node potentially affect control flow.
   bool isControlFlow() => false;
 
@@ skipping 893 matching lines @@
              effects: effects, nativeBehavior: nativeBehavior);
 
   accept(HVisitor visitor) => visitor.visitForeignCode(this);
 
   bool isJsStatement() => isStatement;
   bool canThrow() => canBeNull()
       ? throwBehavior.canThrow
       : throwBehavior.onNonNull.canThrow;
 
   bool onlyThrowsNSM() => throwBehavior.isOnlyNullNSMGuard;
+
+  bool get isAllocation => nativeBehavior != null &&
+      nativeBehavior.isAllocation &&
+      !canBeNull();
 }
 
 class HForeignNew extends HForeign {
   ClassElement element;
 
   /// If this field is not `null`, this call is from an inlined constructor and
   /// we have to register the instantiated type in the code generator. The
   /// [instructionType] of this node is not enough, because we also need the
   /// type arguments. See also [SsaFromAstMixin.currentInlinedInstantiations].
   List<DartType> instantiatedTypes;
 
   HForeignNew(this.element, TypeMask type, List<HInstruction> inputs,
               [this.instantiatedTypes])
       : super(type, inputs);
 
   accept(HVisitor visitor) => visitor.visitForeignNew(this);
+
+  bool get isAllocation => true;
 }
 
 abstract class HInvokeBinary extends HInstruction {
   final Selector selector;
   HInvokeBinary(HInstruction left, HInstruction right, this.selector, type)
       : super(<HInstruction>[left, right], type) {
     sideEffects.clearAllSideEffects();
     sideEffects.clearAllDependencies();
     setUseGvn();
   }
@@ skipping 624 matching lines @@
   int typeCode() => HInstruction.STATIC_STORE_TYPECODE;
   bool typeEquals(other) => other is HStaticStore;
   bool dataEquals(HStaticStore other) => element == other.element;
   bool isJsStatement() => true;
 }
 
 class HLiteralList extends HInstruction {
   HLiteralList(List<HInstruction> inputs, TypeMask type) : super(inputs, type);
   toString() => 'literal list';
   accept(HVisitor visitor) => visitor.visitLiteralList(this);
+
+  bool get isAllocation => true;
 }
 
 /**
  * The primitive array indexing operation. Note that this instruction
  * does not throw because we generate the checks explicitly.
  */
 class HIndex extends HInstruction {
   final Selector selector;
   HIndex(HInstruction receiver, HInstruction index, this.selector, type)
       : super(<HInstruction>[receiver, index], type) {
@@ skipping 734 matching lines @@
 class HDynamicType extends HRuntimeType {
   HDynamicType(DynamicType dartType, TypeMask instructionType)
       : super(const <HInstruction>[], dartType, instructionType);
 
   accept(HVisitor visitor) => visitor.visitDynamicType(this);
 
   int typeCode() => HInstruction.DYNAMIC_TYPE_TYPECODE;
 
   bool typeEquals(HInstruction other) => other is HDynamicType;
 }