dart2js-kernel: Implement Let and PropertySet.

pkg/kernel/lib/frontend/accessors.dart

 // Copyright (c) 2016, 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.
 
 /// A library to help transform compounds and null-aware accessors into
 /// let expressions.
 library kernel.frontend.accessors;
 
 import '../ast.dart';
 
 abstract class Accessor {
+  // [builtBinary] and [builtGetter] capture the inner nodes. Used by
+  // dart2js+rasta for determining how subexpressions map to legacy dart2js Ast
+  // nodes. This will be removed once dart2js type analysis (aka inference) is
+  // reimplemented on kernel.
+  Expression builtBinary;
+  Expression builtGetter;

[asgerf, 2016/11/24 09:44:33]

LGTM

[sra1, 2016/11/24 23:53:52]

Acknowledged.

+
   Expression buildSimpleRead() {
     return _finish(_makeSimpleRead());
   }
 
   /// Returns an assignment to the accessor.
   ///
   /// The returned expression evaluates to the assigned value, unless
   /// [voidContext] is true, in which case it may evaluate to anything.
   Expression buildAssignment(Expression value, {bool voidContext: false}) {
     return _finish(_makeSimpleWrite(value, voidContext));
   }
 
   Expression buildNullAwareAssignment(Expression value, DartType type,
       {bool voidContext: false}) {
     if (voidContext) {
       return _finish(new ConditionalExpression(buildIsNull(_makeRead()),
           _makeWrite(value, voidContext), new NullLiteral(), type));
     }
     var tmp = new VariableDeclaration.forValue(_makeRead());
     return _finish(makeLet(
         tmp,
         new ConditionalExpression(buildIsNull(new VariableGet(tmp)),
             _makeWrite(value, voidContext), new VariableGet(tmp), type)));
   }
 
   Expression buildCompoundAssignment(Name binaryOperator, Expression value,
       {bool voidContext: false, Procedure interfaceTarget}) {
     return _finish(_makeWrite(
-        makeBinary(_makeRead(), binaryOperator, interfaceTarget, value),
+        builtBinary =
+            makeBinary(_makeRead(), binaryOperator, interfaceTarget, value),
         voidContext));
   }
 
   Expression buildPrefixIncrement(Name binaryOperator,
       {bool voidContext: false, Procedure interfaceTarget}) {
     return buildCompoundAssignment(binaryOperator, new IntLiteral(1),
         voidContext: voidContext, interfaceTarget: interfaceTarget);
   }
 
   Expression buildPostfixIncrement(Name binaryOperator,
       {bool voidContext: false, Procedure interfaceTarget}) {
     if (voidContext) {
       return buildPrefixIncrement(binaryOperator,
           voidContext: true, interfaceTarget: interfaceTarget);
     }
     var value = new VariableDeclaration.forValue(_makeRead());
     valueAccess() => new VariableGet(value);
     var dummy = new VariableDeclaration.forValue(_makeWrite(
-        makeBinary(
+        builtBinary = makeBinary(
             valueAccess(), binaryOperator, interfaceTarget, new IntLiteral(1)),
         true));
     return _finish(makeLet(value, makeLet(dummy, valueAccess())));
   }
 
   Expression _makeSimpleRead() => _makeRead();
 
   Expression _makeSimpleWrite(Expression value, bool voidContext) {
     return _makeWrite(value, voidContext);
   }
@@ skipping 45 matching lines @@
   _makeSimpleRead() => new PropertyGet(receiver, name, getter);
   _makeSimpleWrite(Expression value, bool voidContext) {
     return new PropertySet(receiver, name, value, setter);
   }
 
   receiverAccess() {
     _receiverVariable ??= new VariableDeclaration.forValue(receiver);
     return new VariableGet(_receiverVariable);
   }
 
-  _makeRead() => new PropertyGet(receiverAccess(), name, getter);
+  _makeRead() => builtGetter = new PropertyGet(receiverAccess(), name, getter);
 
   _makeWrite(Expression value, bool voidContext) {
     return new PropertySet(receiverAccess(), name, value, setter);
   }
 
   _finish(Expression body) => makeLet(_receiverVariable, body);
 }
 
 /// Special case of [PropertyAccessor] to avoid creating an indirect access to
 /// 'this'.
 class ThisPropertyAccessor extends Accessor {
   Name name;
   Member getter, setter;
 
   ThisPropertyAccessor(this.name, this.getter, this.setter);
 
-  _makeRead() => new PropertyGet(new ThisExpression(), name, getter);
+  _makeRead() => builtGetter = new PropertyGet(new ThisExpression(), name, getter);

[asgerf, 2016/11/24 09:44:33]

Long line (please use dartfmt in pkg/kernel)

[sra1, 2016/11/24 23:53:52]

Done.

 
   _makeWrite(Expression value, bool voidContext) {
     return new PropertySet(new ThisExpression(), name, value, setter);
   }
 }
 
 class NullAwarePropertyAccessor extends Accessor {
   VariableDeclaration receiver;
   Name name;
   Member getter, setter;
   DartType type;
 
   NullAwarePropertyAccessor(
       Expression receiver, this.name, this.getter, this.setter, this.type)
       : this.receiver = makeOrReuseVariable(receiver);
 
   receiverAccess() => new VariableGet(receiver);
 
-  _makeRead() => new PropertyGet(receiverAccess(), name, getter);
+  _makeRead() => builtGetter = new PropertyGet(receiverAccess(), name, getter);
 
   _makeWrite(Expression value, bool voidContext) {
     return new PropertySet(receiverAccess(), name, value, setter);
   }
 
   _finish(Expression body) => makeLet(
       receiver,
       new ConditionalExpression(
           buildIsNull(receiverAccess()), new NullLiteral(), body, type));
 }
@@ skipping 233 matching lines @@
 
 VariableDeclaration makeOrReuseVariable(Expression value) {
   // TODO: Devise a way to remember if a variable declaration was reused
   // or is fresh (hence needs a let binding).
   return new VariableDeclaration.forValue(value);
 }
 
 Expression wrapInvalid(Expression e) {
   return new Let(new VariableDeclaration.forValue(e), new InvalidExpression());
 }