kernel->ssa: Implement for-loops and while-loops

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

Index: pkg/compiler/lib/src/ssa/graph_builder.dart
diff --git a/pkg/compiler/lib/src/ssa/graph_builder.dart b/pkg/compiler/lib/src/ssa/graph_builder.dart
index f7578f37c3ad1e10a755e8431bf0bd314c3b37b0..9898c6a96212c2b817c851af41b88b54a2160bbc 100644
--- a/pkg/compiler/lib/src/ssa/graph_builder.dart
+++ b/pkg/compiler/lib/src/ssa/graph_builder.dart
@@ -2,9 +2,12 @@
 // 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 '../compiler.dart';
 import '../elements/elements.dart';
+import '../resolution/tree_elements.dart';
 import '../types/types.dart';
 
+import 'jump_handler.dart';
 import 'locals_handler.dart';
 import 'nodes.dart';
 
@@ -16,6 +19,13 @@ abstract class GraphBuilder {
   /// Holds the resulting SSA graph.
   final HGraph graph = new HGraph();
 
+  // TODO(het): remove this
+  /// A reference to the compiler.
+  Compiler compiler;
+
+  /// The tree elements for the element being built into an SSA graph.
+  TreeElements get elements;
+
   /// Used to track the locals while building the graph.
   LocalsHandler localsHandler;
 
@@ -24,6 +34,15 @@ abstract class GraphBuilder {
   /// We build the SSA graph by simulating a stack machine.
   List<HInstruction> stack = <HInstruction>[];
 
+  /// The count of nested loops we are currently building.
+  ///
+  /// The loop nesting is consulted when inlining a function invocation. The
+  /// inlining heuristics take this information into account.
+  int loopDepth = 0;
+
+  /// A mapping from jump targets to their handlers.
+  Map<JumpTarget, JumpHandler> jumpTargets = <JumpTarget, JumpHandler>{};
+
   void push(HInstruction instruction) {
     add(instruction);
     stack.add(instruction);
@@ -133,4 +152,14 @@ abstract class GraphBuilder {
     lastAddedParameter = result;
     return result;
   }
+
+  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);
+  }
 }