Reapply "Separate out loop closure information."

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

Index: pkg/compiler/lib/src/ssa/loop_handler.dart
diff --git a/pkg/compiler/lib/src/ssa/loop_handler.dart b/pkg/compiler/lib/src/ssa/loop_handler.dart
index 6e7ad540b2594492c0e9f7f5327ea04623d86d52..c312d670f73beb57f59dc11fef58d6e4555adcaf 100644
--- a/pkg/compiler/lib/src/ssa/loop_handler.dart
+++ b/pkg/compiler/lib/src/ssa/loop_handler.dart
@@ -7,6 +7,7 @@ import 'package:kernel/ast.dart' as ir;
 import '../elements/elements.dart' show JumpTarget, LabelDefinition;
 import '../io/source_information.dart';
 import '../tree/tree.dart' as ast;
+import '../closure.dart' show LoopClosureRepresentationInfo;
 
 import 'builder.dart';
 import 'builder_kernel.dart';
@@ -27,8 +28,8 @@ abstract class LoopHandler<T> {
   /// For while loops, [initialize] and [update] are null.
   /// The [condition] function must return a boolean result.
   /// None of the functions must leave anything on the stack.
-  void handleLoop(T loop, void initialize(), HInstruction condition(),
-      void update(), void body()) {
+  void handleLoop(T loop, LoopClosureRepresentationInfo loopClosureInfo,
+      void initialize(), HInstruction condition(), void update(), void body()) {
     // Generate:
     //  <initializer>
     //  loop-entry:
@@ -38,7 +39,7 @@ abstract class LoopHandler<T> {
     //    goto loop-entry;
     //  loop-exit:
 
-    builder.localsHandler.startLoop(getNode(loop));
+    builder.localsHandler.startLoop(loopClosureInfo);
 
     // The initializer.
     SubExpression initializerGraph = null;
@@ -73,7 +74,7 @@ abstract class LoopHandler<T> {
     conditionEndBlock.addSuccessor(beginBodyBlock);
     builder.open(beginBodyBlock);
 
-    builder.localsHandler.enterLoopBody(getNode(loop));
+    builder.localsHandler.enterLoopBody(loopClosureInfo);
     body();
 
     SubGraph bodyGraph = new SubGraph(beginBodyBlock, builder.lastOpenedBlock);
@@ -122,7 +123,7 @@ abstract class LoopHandler<T> {
             updateBlock);
       }
 
-      builder.localsHandler.enterLoopUpdates(getNode(loop));
+      builder.localsHandler.enterLoopUpdates(loopClosureInfo);
 
       update();
 
@@ -287,9 +288,6 @@ abstract class LoopHandler<T> {
   /// Returns the jump target defined by [node].
   JumpTarget getTargetDefinition(T node);
 
-  /// Returns the corresponding AST node for [node].
-  ast.Node getNode(T node);
-
   /// Determine what kind of loop [node] represents.
   ///
   /// The result is one of the kinds defined in [HLoopBlockInformation].
@@ -321,9 +319,6 @@ class SsaLoopHandler extends LoopHandler<ast.Node> {
     return builder.elements.getTargetDefinition(node);
   }
 
-  @override
-  ast.Node getNode(ast.Node node) => node;
-
   @override
   int loopKind(ast.Node node) => node.accept(const _SsaLoopTypeVisitor());
 
@@ -363,9 +358,6 @@ class KernelLoopHandler extends LoopHandler<ir.TreeNode> {
   JumpHandler createJumpHandler(ir.TreeNode node, {bool isLoopJump}) =>
       builder.createJumpHandler(node, isLoopJump: isLoopJump);
 
-  @override
-  ast.Node getNode(ir.TreeNode node) => astAdapter.getNode(node);
-
   @override
   JumpTarget getTargetDefinition(ir.TreeNode node) =>
       astAdapter.getJumpTarget(node);