Overhaul tree IR visitor and rename IR classes.

pkg/compiler/lib/src/cps_ir/cps_ir_integrity.dart

 library dart2js.cps_ir_integrity;
 
 import 'cps_ir_nodes.dart';
 import 'cps_ir_nodes_sexpr.dart';
 import '../tracer.dart' as tracer;
 
 /// Dump S-expressions on error if the tracer is enabled.
 ///
 /// Technically this has nothing to do with the tracer, but if you want one
 /// enabled, you typically want the other as well, so we use the same flag.
 const bool ENABLE_DUMP = tracer.TRACE_FILTER_PATTERN != null;
 
 /// Performs integrity checks on the CPS IR.
 ///
 /// To be run for debugging purposes, not for use in production.
 ///
 /// The following integrity checks are performed:
 ///
 /// - References are in scope of their definitions.
 /// - Recursive Continuations and InvokeContinuations are marked as recursive.
 /// - InvokeContinuations have the same arity as their target.
 /// - Reference chains are valid doubly-linked lists.
 /// - Reference chains contain exactly the references that are in the IR.
 /// - Each definition object occurs only once in the IR (no redeclaring).
 /// - Each reference object occurs only once in the IR (no sharing).
 ///
 class CheckCpsIntegrity extends RecursiveVisitor {
 
-  ExecutableDefinition topLevelNode;
+  RootNode topLevelNode;
 
   Set<Definition> seenDefinitions = new Set<Definition>();
   Map<Definition, Set<Reference>> seenReferences =
       <Definition, Set<Reference>>{};
 
   Map<Definition, Node> bindings = <Definition, Node>{};
   Set<Continuation> insideContinuations = new Set<Continuation>();
 
   doInScope(Iterable<Definition> defs, Node binding, action()) {
     for (Definition def in defs) {
@@ skipping 31 matching lines @@
     if (node.isReturnContinuation) {
       error('Non-return continuation missing body', node);
     }
     node.parameters.forEach(markAsSeen);
     insideContinuations.add(node);
     doInScope(node.parameters, node, () => visit(node.body));
     insideContinuations.remove(node);
   }
 
   @override
-  visitRunnableBody(RunnableBody node) {
+  visitBody(Body node) {
     markAsSeen(node.returnContinuation);
     if (!node.returnContinuation.isReturnContinuation) {
       error('Return continuation with a body', node);
     }
     doInScope([node.returnContinuation], node, () => visit(node.body));
   }
 
   @override
   visitLetPrim(LetPrim node) {
     markAsSeen(node.primitive);
@@ skipping 110 matching lines @@
       }
     } else {
       sexpr = '(Set DUMP_IR flag to enable)';
     }
     throw 'CPS integrity violation in ${topLevelNode.element}:\n'
           '$message\n\n'
           'SExpr dump (offending node marked with **):\n\n'
           '$sexpr\n';
   }
 
-  void check(ExecutableDefinition node) {
+  void check(RootNode node) {
     topLevelNode = node;
     visit(node);
 
     // Check this last, so out-of-scope references are not classified as
     // a broken reference chain.
     seenDefinitions.forEach(checkReferenceChain);
   }
 
 }