Implement switch statement, without the "complex switch statement" (aka switch statement with conti…

pkg/compiler/lib/src/ssa/kernel_ast_adapter.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.
 
 import 'package:js_runtime/shared/embedded_names.dart';
 import 'package:kernel/ast.dart' as ir;
 
 import '../common.dart';
 import '../common/names.dart';
 import '../compiler.dart';
 import '../constants/expressions.dart';
 import '../constants/values.dart';
 import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
 import '../elements/modelx.dart';
 import '../js/js.dart' as js;
 import '../js_backend/backend_helpers.dart';
 import '../js_backend/js_backend.dart';
 import '../kernel/kernel.dart';
 import '../kernel/kernel_debug.dart';
 import '../native/native.dart' as native;
 import '../resolution/tree_elements.dart';
 import '../tree/tree.dart' as ast;
 import '../types/masks.dart';
 import '../types/types.dart';
 import '../universe/call_structure.dart';
 import '../universe/selector.dart';
 import '../universe/side_effects.dart';
 import '../world.dart';
+import 'jump_handler.dart' show SwitchCaseJumpHandler;
 import 'locals_handler.dart';
 import 'types.dart';
 
 /// A helper class that abstracts all accesses of the AST from Kernel nodes.
 ///
 /// The goal is to remove all need for the AST from the Kernel SSA builder.
 class KernelAstAdapter {
   final Kernel kernel;
   final JavaScriptBackend _backend;
   final Map<ir.Node, ast.Node> _nodeToAst;
   final Map<ir.Node, Element> _nodeToElement;
   final Map<ir.VariableDeclaration, SyntheticLocal> _syntheticLocals =
       <ir.VariableDeclaration, SyntheticLocal>{};
-  final Map<ir.LabeledStatement, KernelJumpTarget> _jumpTargets =
-      <ir.LabeledStatement, KernelJumpTarget>{};
+  // TODO(efortuna): In an ideal world the TreeNodes should be some common
+  // interface we create for both ir.Statements and ir.SwitchCase (the
+  // ContinueSwitchStatement's target is a SwitchCase) rather than general
+  // TreeNode. Talking to Asger about this.
+  final Map<ir.TreeNode, KernelJumpTarget> _jumpTargets =
+      <ir.TreeNode, KernelJumpTarget>{};
   DartTypeConverter _typeConverter;
   ResolvedAst _resolvedAst;
 
   /// Sometimes for resolution the resolved AST element needs to change (for
   /// example, if we're inlining, or if we're in a constructor, but then also
   /// constructing the field values). We keep track of this with a stack.
   final List<ResolvedAst> _resolvedAstStack = <ResolvedAst>[];
 
   KernelAstAdapter(this.kernel, this._backend, this._resolvedAst,
       this._nodeToAst, this._nodeToElement) {
+    KernelJumpTarget.index = 0;
     // TODO(het): Maybe just use all of the kernel maps directly?
     for (FieldElement fieldElement in kernel.fields.keys) {
       _nodeToElement[kernel.fields[fieldElement]] = fieldElement;
     }
     for (FunctionElement functionElement in kernel.functions.keys) {
       _nodeToElement[kernel.functions[functionElement]] = functionElement;
     }
     for (ClassElement classElement in kernel.classes.keys) {
       _nodeToElement[kernel.classes[classElement]] = classElement;
     }
@@ skipping 294 matching lines @@
   bool isLazyStatic(ir.Member member) {
     if (member is ir.Field) {
       FieldElement field = _nodeToElement[member];
       return field.constant == null;
     }
     return false;
   }
 
   LibraryElement get jsHelperLibrary => _backend.helpers.jsHelperLibrary;
 
-  JumpTarget getTargetDefinition(ir.Node node) =>
-      elements.getTargetDefinition(getNode(node));
-
-  JumpTarget getTargetOf(ir.Node node) => elements.getTargetOf(getNode(node));
-
-  KernelJumpTarget getJumpTarget(ir.LabeledStatement labeledStatement) =>
-      _jumpTargets.putIfAbsent(labeledStatement, () {
-        return new KernelJumpTarget();
+  KernelJumpTarget getJumpTarget(ir.TreeNode node) =>
+      _jumpTargets.putIfAbsent(node, () {
+        if (node is ir.LabeledStatement &&
+            _jumpTargets.containsKey((node as ir.LabeledStatement).body)) {
+          return _jumpTargets[(node as ir.LabeledStatement).body];
+        }
+        return new KernelJumpTarget(node);
       });
 
   LabelDefinition getTargetLabel(ir.Node node) =>
       elements.getTargetLabel(getNode(node));
 
   ir.Class get mapLiteralClass =>
       kernel.classes[_backend.helpers.mapLiteralClass];
 
   ir.Procedure get mapLiteralConstructor =>
       kernel.functions[_backend.helpers.mapLiteralConstructor];
@@ skipping 17 matching lines @@
   TypeMask get traceFromExceptionType =>
       TypeMaskFactory.inferredReturnTypeForElement(
           _backend.helpers.traceFromException, _globalInferenceResults);
 
   ir.Procedure get streamIteratorConstructor =>
       kernel.functions[_backend.helpers.streamIteratorConstructor];
 
   TypeMask get streamIteratorConstructorType =>
       TypeMaskFactory.inferredReturnTypeForElement(
           _backend.helpers.streamIteratorConstructor, _globalInferenceResults);
+  ir.Procedure get fallThroughError =>
+      kernel.functions[_backend.helpers.fallThroughError];
+
+  TypeMask get fallThroughErrorType =>
+      TypeMaskFactory.inferredReturnTypeForElement(
+          _backend.helpers.fallThroughError, _globalInferenceResults);
 
   ir.Procedure get mapLiteralUntypedMaker =>
       kernel.functions[_backend.helpers.mapLiteralUntypedMaker];
 
   MemberElement get jsIndexableLength => _backend.helpers.jsIndexableLength;
 
   ir.Procedure get checkConcurrentModificationError =>
       kernel.functions[_backend.helpers.checkConcurrentModificationError];
 
   TypeMask get checkConcurrentModificationErrorReturnType =>
@@ skipping 530 matching lines @@
 
   @override
   ConstantExpression visitStringLiteral(ir.StringLiteral node) {
     return new StringConstantExpression(node.value);
   }
 }
 
 class KernelJumpTarget extends JumpTarget {
   static int index = 0;
 
-  KernelJumpTarget() {
-    labels = <LabelDefinition>[
-      new LabelDefinitionX(null, 'l${index++}', this)..setBreakTarget()
-    ];
+  /// Pointer to the actual executable statements that a jump target refers to.
+  /// If this jump target was not initially constructed with a LabeledStatement,
+  /// this value is identical to originalStatement.
+  // TODO(efortuna): In an ideal world the Node should be some common
+  // interface we create for both ir.Statements and ir.SwitchCase (the
+  // ContinueSwitchStatement's target is a SwitchCase) rather than general
+  // Node. Talking to Asger about this.
+  ir.Node targetStatement;
+
+  /// The original statement used to construct this jump target.
+  /// If this jump target was not initially constructed with a LabeledStatement,
+  /// this value is identical to targetStatement.
+  ir.Node originalStatement;
+
+  @override
+  bool isBreakTarget = false;
+
+  @override
+  bool isContinueTarget = false;
+
+  KernelJumpTarget(this.targetStatement) {
+    labels = <LabelDefinition>[];
+    originalStatement = targetStatement;
+    if (targetStatement is ir.LabeledStatement) {
+      targetStatement = (targetStatement as ir.LabeledStatement).body;
+      labels.add(
+          new LabelDefinitionX(null, 'L${index++}', this)..setBreakTarget());
+      isBreakTarget = true;
+    }
   }
 
   @override
-  bool get isBreakTarget => true;
-
-  set isBreakTarget(bool x) {
-    // do nothing, these are always break targets
-  }
-
-  @override
-  bool get isContinueTarget => false;
-
-  set isContinueTarget(bool x) {
-    // do nothing, these are always break targets
-  }
-
-  @override
   LabelDefinition addLabel(ast.Label label, String labelName) {
     LabelDefinition result = new LabelDefinitionX(label, labelName, this);
     labels.add(result);
     return result;
   }
 
   @override
   ExecutableElement get executableContext => null;
 
   @override
-  bool get isSwitch => false;
+  bool get isSwitch => targetStatement is ir.SwitchStatement;
 
   @override
-  bool get isTarget => true;
+  bool get isTarget => isBreakTarget || isContinueTarget;
 
   @override
   List<LabelDefinition> labels;
 
   @override
   String get name => null;
 
   @override
   int get nestingLevel => 1;
 
   @override
   ast.Node get statement => null;
+
+  String toString() => 'Target:$targetStatement';
 }