dart2js cps: Avoid deep recursion using trampolines and basic blocks.

pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart

 // Copyright (c) 2014, 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.
 
 library tree_ir_nodes;
 
 import '../constants/values.dart' as values;
 import '../dart_types.dart' show DartType, InterfaceType, TypeVariableType;
 import '../elements/elements.dart';
 import '../io/source_information.dart' show SourceInformation;
@@ skipping 1090 matching lines @@
   visitWhileTrue(WhileTrue node) {
     visitStatement(node.body);
   }
 
   visitWhileCondition(WhileCondition node) {
     visitExpression(node.condition);
     visitStatement(node.body);
     visitStatement(node.next);
   }
 
-  visitExpressionStatement(ExpressionStatement node) {
-    visitExpression(node.expression);
-    visitStatement(node.next);
+  visitExpressionStatement(ExpressionStatement inputNode) {
+    // Iterate over chains of expression statements to avoid deep recursion.
+    Statement node = inputNode;
+    while (node is ExpressionStatement) {
+      ExpressionStatement stmt = node;
+      visitExpression(stmt.expression);
+      node = stmt.next;
+    }
+    visitStatement(node);
   }
 
   visitTry(Try node) {
     visitStatement(node.tryBody);
     visitStatement(node.catchBody);
   }
 
   visitGetField(GetField node) {
     visitExpression(node.object);
   }
@@ skipping 195 matching lines @@
   }
 
   visitWhileCondition(WhileCondition node) {
     node.condition = visitExpression(node.condition);
     node.body = visitStatement(node.body);
     node.next = visitStatement(node.next);
     return node;
   }
 
   visitExpressionStatement(ExpressionStatement node) {
-    node.expression = visitExpression(node.expression);
+    // Iterate over chains of expression statements to avoid deep recursion.
+    Statement first = node;
+    while (true) {
+      node.expression = visitExpression(node.expression);
+      if (node.next is ExpressionStatement) {
+        node = node.next;
+      } else {
+        break;
+      }
+    }
     node.next = visitStatement(node.next);
-    return node;
+    return first;
   }
 
   visitTry(Try node) {
     node.tryBody = visitStatement(node.tryBody);
     node.catchBody = visitStatement(node.catchBody);
     return node;
   }
 
   visitGetField(GetField node) {
     node.object = visitExpression(node.object);
@@ skipping 111 matching lines @@
 
   /// Number of uses of the current fallthrough target.
   int get useCount => _stack.last.useCount;
 
   /// Indicate that a statement will fall through to the current fallthrough
   /// target.
   void use() {
     ++_stack.last.useCount;
   }
 }