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

pkg/compiler/lib/src/ssa/graph_builder.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 '../closure.dart';
 import '../common.dart';
 import '../common/codegen.dart' show CodegenRegistry;
 import '../compiler.dart';
 import '../constants/constant_system.dart';
 import '../elements/resolution_types.dart';
@@ skipping 17 matching lines @@
 /// This contains helpers for building the graph and tracking information about
 /// the current state of the graph being built.
 abstract class GraphBuilder {
   /// Holds the resulting SSA graph.
   final HGraph graph = new HGraph();
 
   // TODO(het): remove this
   /// A reference to the compiler.
   Compiler compiler;
 
+  /// True if the builder is processing nodes inside a try statement. This is
+  /// important for unexpected control flow analysis (returns, breaks, etc

[sra1, 2017/01/14 03:18:22]

I would not call it 'unexpected'.
Perhaps say 'Used when generating control flow out of a try block'

[Emily Fortuna, 2017/01/17 23:33:09]

Good point. Updated.

+  /// outside of a try block).
+  bool inTryStatement = false;
+
   /// The JavaScript backend we are targeting in this compilation.
   JavaScriptBackend get backend;
 
   /// The tree elements for the element being built into an SSA graph.
   TreeElements get elements;
 
   CodegenRegistry get registry;
 
   ClosedWorld get closedWorld;
 
@@ skipping 125 matching lines @@
     HParameterValue result = new HParameterValue(parameter, type);
     if (lastAddedParameter == null) {
       graph.entry.addBefore(graph.entry.first, result);
     } else {
       graph.entry.addAfter(lastAddedParameter, result);
     }
     lastAddedParameter = result;
     return result;
   }
 
-  void handleIf(
-      {ast.Node node,
-      void visitCondition(),
-      void visitThen(),
-      void visitElse(),
-      SourceInformation sourceInformation}) {
-    SsaBranchBuilder branchBuilder = new SsaBranchBuilder(this, compiler, node);
-    branchBuilder.handleIf(visitCondition, visitThen, visitElse,
-        sourceInformation: sourceInformation);
-  }
-
   HSubGraphBlockInformation wrapStatementGraph(SubGraph statements) {
     if (statements == null) return null;
     return new HSubGraphBlockInformation(statements);
   }
 
   HSubExpressionBlockInformation wrapExpressionGraph(SubExpression expression) {
     if (expression == null) return null;
     return new HSubExpressionBlockInformation(expression);
   }
 
@@ skipping 26 matching lines @@
 
     HInstruction typeInfo = new HTypeInfoExpression(
         TypeInfoExpressionKind.INSTANCE,
         (type.element as ClassElement).thisType,
         rtiInputs,
         closedWorld.commonMasks.dynamicType);
     add(typeInfo);
     return callSetRuntimeTypeInfo(typeInfo, newObject);
   }
 
+  /// Called when control flow is about to change, in which case we need to
+  /// specify special successors if we are already in a try/catch/finally block.
+  void handleInTryStatement() {
+    if (!inTryStatement) return;
+    HBasicBlock block = close(new HExitTry());
+    HBasicBlock newBlock = graph.addNewBlock();
+    block.addSuccessor(newBlock);
+    open(newBlock);
+  }
+
   HInstruction callSetRuntimeTypeInfo(
       HInstruction typeInfo, HInstruction newObject);
 
   /// The element for which this SSA builder is being used.
   Element get targetElement;
   TypeBuilder get typeBuilder;
 }
 
 class ReifiedTypeRepresentationBuilder
     implements DartTypeVisitor<dynamic, GraphBuilder> {
@@ skipping 89 matching lines @@
     if (unaliased is ResolutionTypedefType) throw 'unable to unalias $type';
     unaliased.accept(this, builder);
   }
 
   void visitDynamicType(ResolutionDynamicType type, GraphBuilder builder) {
     JavaScriptBackend backend = builder.compiler.backend;
     ClassElement cls = backend.helpers.DynamicRuntimeType;
     builder.push(new HDynamicType(type, new TypeMask.exact(cls, closedWorld)));
   }
 }