cps-ir: Only use fallback compiler for platform functions.

pkg/compiler/lib/src/js_backend/codegen/task.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.
 
 /// Generate code using the cps-based IR pipeline.
 library code_generator_task;
 
 import '../js_backend.dart';import '../../dart2jslib.dart';
 import '../../source_file.dart';
 import '../../cps_ir/cps_ir_nodes.dart' as cps;
@@ skipping 10 matching lines @@
 import '../../cps_ir/optimizers.dart';
 import '../../tracer.dart';
 import '../../dart_backend/statement_rewriter.dart';
 import '../../dart_backend/copy_propagator.dart';
 import '../../dart_backend/loop_rewriter.dart';
 import '../../dart_backend/logical_rewriter.dart';
 import '../../js_backend/codegen/codegen.dart';
 import '../../ssa/ssa.dart' as ssa;
 
 class CspFunctionCompiler implements FunctionCompiler {
+  final IrBuilderTask irBuilderTask;
+  final ConstantSystem constantSystem;
+  final Compiler compiler;
+
+  // TODO(karlklose,sigurm): remove and update dart-doc of [compile].
+  final FunctionCompiler fallbackCompiler;
 
   // TODO(sigurdm): Assign this.
   Tracer tracer;
 
-  String get name => 'CPS Ir pipeline';
-
-  final IrBuilderTask irBuilderTask;
-
-  final ConstantSystem constantSystem;
-
-  final Compiler compiler;
-
-  // Remember to update dart-doc of [compile] when this field is removed.
-  final FunctionCompiler fallbackCompiler;
-
   CspFunctionCompiler(Compiler compiler, JavaScriptBackend backend)
       : irBuilderTask = new IrBuilderTask(compiler),
         fallbackCompiler = new ssa.SsaFunctionCompiler(backend),
         constantSystem = backend.constantSystem,
         compiler = compiler;
 
+  String get name => 'CPS Ir pipeline';
+
   /// Generates JavaScript code for `work.element`. First tries to use the
   /// Cps Ir -> tree ir -> js pipeline, and if that fails due to language
-  /// features not implemented it will fall back to the ssa pipeline.
+  /// features not implemented it will fall back to the ssa pipeline (for
+  /// platform code) or will cancel compilation (for user code).
   js.Fun compile(CodegenWorkItem work) {
     AstElement element = work.element;
     return compiler.withCurrentElement(element, () {
       try {
         if (tracer != null) {
           tracer.traceCompilation(element.name, null);
         }
         cps.FunctionDefinition cpsFunction = compileToCpsIR(element);
         cpsFunction = optimizeCpsIR(cpsFunction);
         tree_ir.FunctionDefinition treeFunction = compileToTreeIR(cpsFunction);
         treeFunction = optimizeTreeIR(treeFunction);
         return compileToJavaScript(work, treeFunction);
       } on CodegenBailout catch (e) {
-        compiler.log('Falling back to SSA compiler for $element'
-            ' (${e.message})');
-        return fallbackCompiler.compile(work);
+        if (element.library.isPlatformLibrary) {
+          compiler.log('Falling back to SSA compiler for $element'
+              ' (${e.message})');
+          return fallbackCompiler.compile(work);
+        } else {
+          String message = "Unable to compile $element with the new compiler.\n"
+              "  Reason: ${e.message}";
+          compiler.internalError(element, message);
+        }
       }
     });
   }
 
   void giveUp(String reason) {
     throw new CodegenBailout(null, reason);
   }
 
   void traceGraph(String title, var irObject) {
     if (tracer != null) {
@@ skipping 106 matching lines @@
   SourceFile sourceFileOfElement(Element element) {
     return element.implementation.compilationUnit.script.file;
   }
 
   js.Fun buildJavaScriptFunction(FunctionElement element,
                                  List<js.Parameter> parameters,
                                  js.Block body) {
     return attachPosition(new js.Fun(parameters, body), element);
   }
 }