Rename fletch -> dartino

pkg/fletchc/lib/src/closure_environment.dart

-// Copyright (c) 2015, the Dartino 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.md file.
-
-library fletchc.closure_environment;
-
-import 'package:compiler/src/resolution/semantic_visitor.dart';
-
-import 'package:compiler/src/resolution/operators.dart' show
-    AssignmentOperator,
-    BinaryOperator,
-    IncDecOperator,
-    UnaryOperator;
-
-import 'package:compiler/src/elements/elements.dart';
-import 'package:compiler/src/resolution/tree_elements.dart';
-import 'package:compiler/src/resolution/send_resolver.dart';
-import 'package:compiler/src/tree/tree.dart';
-import 'package:compiler/src/universe/selector.dart';
-import 'package:compiler/src/universe/call_structure.dart';
-import 'package:compiler/src/diagnostics/spannable.dart' show
-    Spannable,
-    SpannableAssertionFailure;
-import 'package:compiler/src/dart_types.dart';
-
-enum CaptureMode {
-  /**
-   * If a local is marked [ByValue], the local is read in closures.
-   */
-  ByValue,
-
-  /**
-   * If a local is marked [ByReference], a write to the local can be observed
-   * from a closure.
-   *
-   * In this case, the local must be boxed.
-   */
-  ByReference,
-}
-
-/**
- * The computed infomation about a closures usage of locals and 'this'.
- */
-class ClosureInfo {
-  bool isThisFree = false;
-  Set<LocalElement> free = new Set<LocalElement>();
-
-  void markUsed(LocalElement element) {
-    free.add(element);
-  }
-}
-
-class ClosureEnvironment {
-  /**
-   * A map of locals that are captured, and how.
-   */
-  final Map<LocalElement, CaptureMode> captured = <LocalElement, CaptureMode>{};
-
-  /**
-   * A map of all nested closures of [function], and what locals they capture.
-   */
-  final Map<FunctionElement, ClosureInfo> closures =
-      <FunctionElement, ClosureInfo>{};
-
-  bool shouldBeBoxed(element) => captured[element] == CaptureMode.ByReference;
-}
-
-class ClosureVisitor
-    extends SemanticVisitor
-    with TraversalSendMixin,
-         SemanticSendResolvedMixin,
-         BaseImplementationOfLocalsMixin,
-         VariableBulkMixin,
-         ParameterBulkMixin,
-         FunctionBulkMixin,
-         ConstructorBulkMixin,
-         InitializerBulkMixin
-    implements SemanticSendVisitor, SemanticDeclarationVisitor {
-  final ClosureEnvironment closureEnvironment = new ClosureEnvironment();
-
-  /**
-   * A set of all locals that are assigned in [function] excluding nested
-   * closures. This is the inverse of implicit final locals.
-   */
-  final Set<LocalElement> locallyAssigned = new Set<LocalElement>();
-
-  final MemberElement element;
-
-  ExecutableElement currentElement;
-
-  bool inInitializers = false;
-
-  ClosureVisitor(this.element, TreeElements elements)
-      : super(elements);
-
-  SemanticSendVisitor get sendVisitor => this;
-  SemanticDeclarationVisitor get declVisitor => this;
-
-  ClosureEnvironment compute() {
-    assert(element.memberContext == element);
-    assert(currentElement == null);
-    currentElement = element;
-    if (element.node != null) element.resolvedAst.node.accept(this);
-    assert(currentElement == element);
-    return closureEnvironment;
-  }
-
-  void visitNode(Node node) {
-    node.visitChildren(this);
-  }
-
-  void visitVariableDefinitions(VariableDefinitions node) {
-    for (Node definition in node.definitions) {
-      VariableElement element = elements[definition];
-      Expression initializer = element.initializer;
-      if (initializer != null) initializer.accept(this);
-    }
-  }
-
-  void visitFunctionExpression(FunctionExpression node) {
-    ExecutableElement oldElement = currentElement;
-    currentElement = elements.getFunctionDefinition(node);
-    if (currentElement != element) {
-      ClosureInfo info = new ClosureInfo();
-      closureEnvironment.closures[currentElement] = info;
-    }
-    if (currentElement.isConstructor) {
-      inInitializers = true;
-      visitInitializers(node, null);
-      inInitializers = false;
-    }
-    node.body.accept(this);
-    currentElement = oldElement;
-  }
-
-  void visitFieldInitializer(
-      SendSet node,
-      FieldElement field,
-      Node initializer,
-      _) {
-    initializer.accept(this);
-  }
-
-  void visitSuperConstructorInvoke(
-      Send node,
-      ConstructorElement superConstructor,
-      InterfaceType type,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
-    arguments.accept(this);
-  }
-
-  void visitThisConstructorInvoke(
-      Send node,
-      ConstructorElement thisConstructor,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
-    arguments.accept(this);
-  }
-
-  void markUsed(LocalElement element, CaptureMode use) {
-    if (currentElement == element.executableContext) {
-      // If a local is assigned in the declaring context, and it is captured
-      // at this point, mark it as used by reference (we assign to the value
-      // after it's captured).
-      if (use == CaptureMode.ByReference) {
-        if (closureEnvironment.captured.containsKey(element)) {
-          closureEnvironment.captured[element] = use;
-        } else {
-          locallyAssigned.add(element);
-        }
-      }
-    } else {
-      if (locallyAssigned.contains(element)) use = CaptureMode.ByReference;
-      // If the element is used by reference, upgrade it unconditionally.
-      if (use == CaptureMode.ByReference) {
-        closureEnvironment.captured[element] = use;
-      } else {
-        // If it's used by value, only add it to `captured` if it's not
-        // there already - if it's in there it can be by reference.
-        closureEnvironment.captured.putIfAbsent(element, () => use);
-      }
-      ExecutableElement current = currentElement;
-      // Mark all closures from the current to the one where `element` is
-      // defined, as used in that closure. That makes sure we capture it in
-      // all intermidiate closures, thus making it available in the current.
-      while (current != element.executableContext) {
-        ClosureInfo info = closureEnvironment.closures[current];
-        info.markUsed(element);
-        current = (current as Local).executableContext;
-      }
-    }
-  }
-
-  void markThisUsed() {
-    assert(!inInitializers);
-    ExecutableElement current = currentElement;
-    while (current != element) {
-      ClosureInfo info = closureEnvironment.closures[current];
-      info.isThisFree = true;
-      current = (current as Local).executableContext;
-    }
-  }
-
-  void handleLocalGet(Send node, LocalElement element, _) {
-    markUsed(element, CaptureMode.ByValue);
-  }
-
-  void handleLocalSet(
-      SendSet node,
-      LocalElement element,
-      Node rhs,
-      _) {
-    markUsed(element, CaptureMode.ByReference);
-    rhs.accept(this);
-  }
-
-  void handleLocalInvoke(
-      Send node,
-      LocalElement element,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
-    markUsed(element, CaptureMode.ByValue);
-    arguments.accept(this);
-  }
-
-  void visitThisPropertySet(Send node, Name name, Node rhs, _) {
-    markThisUsed();
-    super.visitThisPropertySet(node, name, rhs, null);
-  }
-
-  void visitLocalVariablePrefix(
-      SendSet node,
-      LocalVariableElement element,
-      IncDecOperator operator,
-      _) {
-    markUsed(element, CaptureMode.ByReference);
-  }
-
-  void visitLocalVariablePostfix(
-      SendSet node,
-      LocalVariableElement element,
-      IncDecOperator operator,
-      _) {
-    markUsed(element, CaptureMode.ByReference);
-  }
-
-  void visitThisPropertyInvoke(
-      Send node,
-      NodeList arguments,
-      Selector selector,
-      _) {
-    markThisUsed();
-    arguments.accept(this);
-  }
-
-  void visitThisPropertyGet(
-      Send node,
-      Name name,
-      _) {
-    markThisUsed();
-  }
-
-  void visitThisGet(Node node, _) {
-    markThisUsed();
-  }
-
-  void visitIs(Send node, Node expression, DartType type, _) {
-    // TODO(ajohnsen): Type is used ByValue.
-    expression.accept(this);
-  }
-
-  void visitIsNot(Send node, Node expression, DartType type, _) {
-    // TODO(ajohnsen): Type is used ByValue.
-    expression.accept(this);
-  }
-
-  void visitAs(Send node, Node expression, DartType type, _) {
-    // TODO(ajohnsen): Type is used ByValue.
-    expression.accept(this);
-  }
-
-  void visitAssert(Assert node) {
-    // TODO(ajohnsen): Only visit in checked mode.
-    node.condition.accept(this);
-    node.message?.accept(this);
-  }
-
-  void visitLocalVariableCompound(
-      Send node,
-      LocalVariableElement variable,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markUsed(variable, CaptureMode.ByReference);
-    super.visitLocalVariableCompound(node, variable, operator, rhs, null);
-  }
-
-  void internalError(Spannable spannable, String message) {
-    throw new SpannableAssertionFailure(spannable, message);
-  }
-
-  void apply(Node node, [_]) {
-    node.accept(this);
-  }
-
-  void visitThisInvoke(
-      Send node,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
-    markThisUsed();
-    super.visitThisInvoke(node, arguments, callStructure, null);
-  }
-
-  void visitSuperFieldGet(
-      Send node,
-      FieldElement field,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldGet(node, field, null);
-  }
-
-  void visitSuperFieldSet(
-      SendSet node,
-      FieldElement field,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldSet(node, field, rhs, null);
-  }
-
-  void visitSuperFieldInvoke(
-      Send node,
-      FieldElement field,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldInvoke(node, field, arguments, callStructure, null);
-  }
-
-  void visitSuperMethodGet(
-      Send node,
-      MethodElement method,
-      _) {
-    markThisUsed();
-    super.visitSuperMethodGet(node, method, null);
-  }
-
-  void visitSuperGetterGet(
-      Send node,
-      FunctionElement getter,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterGet(node, getter, null);
-  }
-
-  void visitSuperSetterSet(
-      SendSet node,
-      FunctionElement setter,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperSetterSet(node, setter, rhs, null);
-  }
-
-  void visitSuperGetterInvoke(
-      Send node,
-      FunctionElement getter,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterInvoke(node, getter, arguments, callStructure, null);
-  }
-
-  void visitTypeVariableTypeLiteralGet(
-      Send node,
-      TypeVariableElement element,
-      _) {
-    // TODO(ajohnsen): Visit 'this' for type literal support, except for
-    // closures in initializers.
-    super.visitTypeVariableTypeLiteralGet(node, element, null);
-  }
-
-  void visitTypeVariableTypeLiteralInvoke(
-      Send node,
-      TypeVariableElement element,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
-    // TODO(ajohnsen): Visit 'this' for type literal support, except for
-    // closures in initializers.
-    super.visitTypeVariableTypeLiteralInvoke(
-        node, element, arguments, callStructure, null);
-  }
-
-  void visitSuperBinary(
-      Send node,
-      FunctionElement function,
-      BinaryOperator operator,
-      Node argument,
-      _) {
-    markThisUsed();
-    super.visitSuperBinary(node, function, operator, argument, null);
-  }
-
-  void visitSuperIndex(
-      Send node,
-      FunctionElement function,
-      Node index,
-      _) {
-    markThisUsed();
-    super.visitSuperIndex(node, function, index, null);
-  }
-
-  void visitSuperIndexPostfix(
-      SendSet node,
-      FunctionElement getter,
-      FunctionElement setter,
-      Node index,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperIndexPostfix(node, getter, setter, index, operator, null);
-  }
-
-  void visitSuperNotEquals(
-      Send node,
-      FunctionElement function,
-      Node argument,
-      _) {
-    markThisUsed();
-    super.visitSuperNotEquals(node, function, argument, null);
-  }
-
-  void visitSuperEquals(
-      Send node,
-      FunctionElement function,
-      Node argument,
-      _) {
-    markThisUsed();
-    super.visitSuperEquals(node, function, argument, null);
-  }
-
-  void visitSuperUnary(
-      Send node,
-      UnaryOperator operator,
-      FunctionElement function,
-      _) {
-    markThisUsed();
-    super.visitSuperUnary(node, operator, function, null);
-  }
-
-  void visitSuperIndexSet(
-      Send node,
-      FunctionElement function,
-      Node index,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperIndexSet(node, function, index, rhs, null);
-  }
-
-  void visitThisPropertyCompound(
-      Send node,
-      Name name,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitThisPropertyCompound(
-        node, name, operator, rhs, null);
-  }
-
-  void visitParameterCompound(
-      Send node,
-      ParameterElement parameter,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markUsed(parameter, CaptureMode.ByReference);
-    super.visitParameterCompound(node, parameter, operator, rhs, null);
-  }
-
-  void visitSuperFieldCompound(
-      Send node,
-      FieldElement field,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldCompound(node, field, operator, rhs, null);
-  }
-
-  void visitSuperGetterSetterCompound(
-      Send node,
-      FunctionElement getter,
-      FunctionElement setter,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterSetterCompound(
-        node, getter, setter, operator, rhs, null);
-  }
-
-  void visitSuperMethodSetterCompound(
-      Send node,
-      FunctionElement method,
-      FunctionElement setter,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperMethodSetterCompound(
-        node, method, setter, operator, rhs, null);
-  }
-
-  void visitSuperFieldSetterCompound(
-      Send node,
-      FieldElement field,
-      FunctionElement setter,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldSetterCompound(
-        node, field, setter, operator, rhs, null);
-  }
-
-  void visitSuperGetterFieldCompound(
-      Send node,
-      FunctionElement getter,
-      FieldElement field,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterFieldCompound(
-        node, getter, field, operator, rhs, null);
-  }
-
-  void visitSuperCompoundIndexSet(
-      Send node,
-      FunctionElement getter,
-      FunctionElement setter,
-      Node index,
-      AssignmentOperator operator,
-      Node rhs,
-      _) {
-    markThisUsed();
-    super.visitSuperCompoundIndexSet(
-        node, getter, setter, index, operator, rhs, null);
-  }
-
-  void visitParameterPrefix(
-      Send node,
-      ParameterElement parameter,
-      IncDecOperator operator,
-      _) {
-    markUsed(parameter, CaptureMode.ByReference);
-    super.visitParameterPrefix(node, parameter, operator, null);
-  }
-
-  void visitThisPropertyPrefix(
-      Send node,
-      Name name,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitThisPropertyPrefix(
-        node, name, operator, null);
-  }
-
-  void visitSuperFieldPrefix(
-      Send node,
-      FieldElement field,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldPrefix(node, field, operator, null);
-  }
-
-  void visitSuperFieldFieldPrefix(
-      Send node,
-      FieldElement readField,
-      FieldElement writtenField,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldFieldPrefix(
-        node, readField, writtenField, operator, null);
-  }
-
-  void visitSuperFieldSetterPrefix(
-      Send node,
-      FieldElement field,
-      FunctionElement setter,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldSetterPrefix(node, field, setter, operator, null);
-  }
-
-  void visitSuperGetterSetterPrefix(
-      Send node,
-      FunctionElement getter,
-      FunctionElement setter,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterSetterPrefix(node, getter, setter, operator, null);
-  }
-
-  void visitSuperGetterFieldPrefix(
-      Send node,
-      FunctionElement getter,
-      FieldElement field,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterFieldPrefix(node, getter, field, operator, null);
-  }
-
-  void visitSuperMethodSetterPrefix(
-      Send node,
-      FunctionElement method,
-      FunctionElement setter,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperMethodSetterPrefix(node, method, setter, operator, null);
-  }
-
-  void visitTypeVariableTypeLiteralPrefix(
-      Send node,
-      TypeVariableElement element,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitTypeVariableTypeLiteralPrefix(node, element, operator, null);
-  }
-
-  void visitParameterPostfix(
-      Send node,
-      ParameterElement parameter,
-      IncDecOperator operator,
-      _) {
-    markUsed(parameter, CaptureMode.ByReference);
-    super.visitParameterPostfix(node, parameter, operator, null);
-  }
-
-  void visitThisPropertyPostfix(
-      Send node,
-      Name name,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitThisPropertyPostfix(
-        node, name, operator, null);
-  }
-
-  void visitSuperFieldPostfix(
-      Send node,
-      FieldElement field,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldPostfix(node, field, operator, null);
-  }
-
-  void visitSuperFieldFieldPostfix(
-      Send node,
-      FieldElement readField,
-      FieldElement writtenField,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldFieldPostfix(
-        node, readField, writtenField, operator, null);
-  }
-
-  void visitSuperFieldSetterPostfix(
-      Send node,
-      FieldElement field,
-      FunctionElement setter,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperFieldSetterPostfix(node, field, setter, operator, null);
-  }
-
-  void visitSuperGetterSetterPostfix(
-      Send node,
-      FunctionElement getter,
-      FunctionElement setter,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterSetterPostfix(node, getter, setter, operator, null);
-  }
-
-  void visitSuperGetterFieldPostfix(
-      Send node,
-      FunctionElement getter,
-      FieldElement field,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperGetterFieldPostfix(node, getter, field, operator, null);
-  }
-
-  void visitSuperMethodSetterPostfix(
-      Send node,
-      FunctionElement method,
-      FunctionElement setter,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperMethodSetterPostfix(node, method, setter, operator, null);
-  }
-
-  void visitTypeVariableTypeLiteralPostfix(
-      Send node,
-      TypeVariableElement element,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitTypeVariableTypeLiteralPostfix(node, element, operator, null);
-  }
-
-  void visitSuperIndexPrefix(
-      Send node,
-      FunctionElement indexFunction,
-      FunctionElement indexSetFunction,
-      Node index,
-      IncDecOperator operator,
-      _) {
-    markThisUsed();
-    super.visitSuperIndexPrefix(
-        node, indexFunction, indexSetFunction, index, operator, null);
-  }
-
-  @override
-  void visitTypeAnnotation(TypeAnnotation node) {
-  // This is to avoid the inherited implementation that visits children and
-  // throws when encountering anything unresolved.
-  }
-
-  void handleImmutableLocalSet(
-      SendSet node,
-      LocalElement element,
-      Node rhs,
-      _) {
-    apply(rhs);
-  }
-
-  void bulkHandleNode(Node node, String message, _) {
-  }
-
-  void applyInitializers(FunctionExpression initializers, _) {
-  }
-
-  void applyParameters(NodeList parameters, _) {
-  }
-}