Reapply "Use backend targets to run Kernel transformations in Fasta"

This reverts commit 0b424ca5d2

R=ahe@google.com

Review-Url: https://codereview.chromium.org/2919003003 .

pkg/analyzer/lib/src/fasta/analyzer_target.dart

@@ -21,7 +21,7 @@ class AnalyzerTarget extends KernelTarget {
       DillTarget dillTarget, TranslateUri uriTranslator, bool strongMode,
       [Map<String, Source> uriToSource])
       : super(PhysicalFileSystem.instance, dillTarget, uriTranslator,
-            strongMode, uriToSource);
+            uriToSource);
 
   @override
   AnalyzerLoader<Library> createLoader() => new AnalyzerLoader<Library>(this);

pkg/compiler/lib/src/kernel/fasta_support.dart

@@ -22,6 +22,7 @@ import 'package:front_end/file_system.dart';
 import 'package:front_end/physical_file_system.dart';
 import 'package:front_end/src/fasta/kernel/utils.dart';
 import 'package:kernel/ast.dart' show Source, Library;
+import 'package:kernel/target/targets.dart' show TargetFlags;
 
 import 'package:front_end/src/fasta/builder/builder.dart' show LibraryBuilder;
 import 'package:front_end/src/fasta/compiler_context.dart' show CompilerContext;
@@ -89,8 +90,7 @@ class KernelTargetForDart2js extends KernelTarget {
   KernelTargetForDart2js(
       DillTarget target, TranslateUri uriTranslator, bool strongMode,
       [Map<String, Source> uriToSource])
-      : super(PhysicalFileSystem.instance, target, uriTranslator, strongMode,
-            uriToSource);
+      : super(PhysicalFileSystem.instance, target, uriTranslator, uriToSource);
   @override
   SourceLoader<Library> createLoader() =>
       new SourceLoaderForDart2js<Library>(fileSystem, this);
@@ -139,8 +139,9 @@ class SourceLoaderForDart2js<L> extends SourceLoader<L> {
 /// Specializes [DillTarget] to build kernel for dart2js: JS-specific libraries
 /// are included in the SDK, and native clauses have no string parameter.
 class DillTargetForDart2js extends DillTarget {
-  DillTargetForDart2js(Ticker ticker, TranslateUri uriTranslator)
-      : super(ticker, uriTranslator, "none");
+  DillTargetForDart2js(Ticker ticker, TranslateUri uriTranslator,
+      {TargetFlags flags})
+      : super(ticker, uriTranslator, "none", flags: flags);
 
   @override
   Token skipNativeClause(Token token) => _skipNative(token);

pkg/front_end/lib/kernel_generator.dart

@@ -13,6 +13,7 @@ import 'src/fasta/dill/dill_target.dart' show DillTarget;
 import 'src/fasta/errors.dart' show InputError;
 import 'src/fasta/kernel/kernel_target.dart' show KernelTarget;
 import 'package:kernel/kernel.dart' show Program;
+import 'package:kernel/target/targets.dart' show TargetFlags;
 import 'src/fasta/ticker.dart' show Ticker;
 import 'src/fasta/translate_uri.dart' show TranslateUri;
 import 'src/simple_error.dart';
@@ -52,15 +53,16 @@ Future<Program> kernelForProgram(Uri source, CompilerOptions options) async {
   try {
     TranslateUri uriTranslator = await pOptions.getUriTranslator();
 
-    var dillTarget =
-        new DillTarget(new Ticker(isVerbose: false), uriTranslator, "vm");
+    var dillTarget = new DillTarget(
+        new Ticker(isVerbose: false), uriTranslator, "vm_fasta",
+        flags: new TargetFlags(strongMode: options.strongMode));
     var summary = await pOptions.sdkSummaryProgram;
     if (summary != null) {
       dillTarget.loader.appendLibraries(summary);
     }
 
-    var kernelTarget = new KernelTarget(
-        options.fileSystem, dillTarget, uriTranslator, options.strongMode);
+    var kernelTarget =
+        new KernelTarget(options.fileSystem, dillTarget, uriTranslator);
     kernelTarget.read(source);
 
     await dillTarget.buildOutlines();
@@ -148,8 +150,9 @@ Future<Program> kernelForBuildUnit(
   try {
     TranslateUri uriTranslator = await pOptions.getUriTranslator();
 
-    var dillTarget =
-        new DillTarget(new Ticker(isVerbose: false), uriTranslator, "vm");
+    var dillTarget = new DillTarget(
+        new Ticker(isVerbose: false), uriTranslator, "vm_fasta",
+        flags: new TargetFlags(strongMode: options.strongMode));
     var summary = await pOptions.sdkSummaryProgram;
     if (summary != null) {
       dillTarget.loader.appendLibraries(summary);
@@ -164,8 +167,8 @@ Future<Program> kernelForBuildUnit(
 
     await dillTarget.buildOutlines();
 
-    var kernelTarget = new KernelTarget(
-        options.fileSystem, dillTarget, uriTranslator, options.strongMode);
+    var kernelTarget =
+        new KernelTarget(options.fileSystem, dillTarget, uriTranslator);
     sources.forEach(kernelTarget.read);
     await kernelTarget.buildOutlines();
 

pkg/front_end/lib/src/fasta/compile_platform.dart

@@ -24,6 +24,8 @@ import 'ticker.dart' show Ticker;
 
 import 'translate_uri.dart' show TranslateUri;
 
+import 'package:kernel/target/targets.dart' show TargetFlags;
+
 const int iterations = const int.fromEnvironment("iterations", defaultValue: 1);
 
 Future mainEntryPoint(List<String> arguments) async {
@@ -71,10 +73,11 @@ Future compilePlatformInternal(CompilerContext c, Ticker ticker, Uri patchedSdk,
       .parse(c.fileSystem, patchedSdk, packages: c.options.packages);
   ticker.logMs("Read packages file");
 
-  DillTarget dillTarget =
-      new DillTarget(ticker, uriTranslator, c.options.target);
-  KernelTarget kernelTarget = new KernelTarget(c.fileSystem, dillTarget,
-      uriTranslator, c.options.strongMode, c.uriToSource);
+  DillTarget dillTarget = new DillTarget(
+      ticker, uriTranslator, c.options.target,
+      flags: new TargetFlags(strongMode: c.options.strongMode));
+  KernelTarget kernelTarget =
+      new KernelTarget(c.fileSystem, dillTarget, uriTranslator, c.uriToSource);
 
   kernelTarget.read(Uri.parse("dart:core"));
   await dillTarget.buildOutlines();

pkg/front_end/lib/src/fasta/compiler_command_line.dart

@@ -91,7 +91,7 @@ class CompilerCommandLine extends CommandLine {
   bool get strongMode => options.containsKey("--strong-mode");
 
   String get target {
-    return options["-t"] ?? options["--target"] ?? "vm";
+    return options["-t"] ?? options["--target"] ?? "vm_fasta";
   }
 
   static dynamic withGlobalOptions(String programName, List<String> arguments,

pkg/front_end/lib/src/fasta/dill/dill_target.dart

@@ -8,7 +8,7 @@ import 'dart:async' show Future;
 
 import 'package:kernel/ast.dart' show Class;
 
-import 'package:kernel/target/targets.dart' show getTarget;
+import 'package:kernel/target/targets.dart' show getTarget, TargetFlags;
 
 import '../errors.dart' show internalError;
 import '../kernel/kernel_builder.dart' show ClassBuilder;
@@ -23,8 +23,10 @@ class DillTarget extends TargetImplementation {
   DillLoader loader;
 
   DillTarget(
-      Ticker ticker, TranslateUri uriTranslator, String backendTargetName)
-      : super(ticker, uriTranslator, getTarget(backendTargetName, null)) {
+      Ticker ticker, TranslateUri uriTranslator, String backendTargetName,
+      {TargetFlags flags})
+      : super(ticker, uriTranslator,
+            getTarget(backendTargetName, flags ?? new TargetFlags())) {
     loader = new DillLoader(this);
   }
 

pkg/front_end/lib/src/fasta/fasta.dart

@@ -16,13 +16,9 @@ import 'package:front_end/src/fasta/kernel/utils.dart';
 import 'package:kernel/binary/ast_to_binary.dart'
     show LibraryFilteringBinaryPrinter;
 
-import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
-
-import 'package:kernel/core_types.dart' show CoreTypes;
-
 import 'package:kernel/kernel.dart' show Library, Program, loadProgramFromBytes;
 
-import 'package:kernel/target/targets.dart' show Target, TargetFlags, getTarget;
+import 'package:kernel/target/targets.dart' show TargetFlags;
 
 import 'compiler_command_line.dart' show CompilerCommandLine;
 
@@ -118,13 +114,14 @@ class CompileTask {
   CompileTask(this.c, this.ticker);
 
   DillTarget createDillTarget(TranslateUri uriTranslator) {
-    return new DillTarget(ticker, uriTranslator, c.options.target);
+    return new DillTarget(ticker, uriTranslator, c.options.target,
+        flags: new TargetFlags(strongMode: c.options.strongMode));
   }
 
   KernelTarget createKernelTarget(
       DillTarget dillTarget, TranslateUri uriTranslator, bool strongMode) {
     return new KernelTarget(
-        c.fileSystem, dillTarget, uriTranslator, strongMode, c.uriToSource);
+        c.fileSystem, dillTarget, uriTranslator, c.uriToSource);
   }
 
   Future<KernelTarget> buildOutline([Uri output]) async {
@@ -186,7 +183,7 @@ Future<CompilationResult> parseScript(
 Future<CompilationResult> parseScriptInFileSystem(
     Uri fileName, FileSystem fileSystem, Uri packages, Uri patchedSdk,
     {bool verbose: false, bool strongMode: false, String backendTarget}) async {
-  backendTarget ??= "vm";
+  backendTarget ??= "vm_fasta";
   try {
     if (!await fileSystem.entityForUri(fileName).exists()) {
       return new CompilationResult.error(
@@ -197,23 +194,20 @@ Future<CompilationResult> parseScriptInFileSystem(
           formatUnexpected(patchedSdk, -1, "Patched sdk directory not found."));
     }
 
-    CoreTypes coreTypes;
-    ClassHierarchy hierarchy;
     Program program;
     try {
       TranslateUri uriTranslator =
           await TranslateUri.parse(fileSystem, patchedSdk, packages: packages);
       final Ticker ticker = new Ticker(isVerbose: verbose);
-      final DillTarget dillTarget =
-          new DillTarget(ticker, uriTranslator, backendTarget);
+      final DillTarget dillTarget = new DillTarget(
+          ticker, uriTranslator, backendTarget,
+          flags: new TargetFlags(strongMode: strongMode));
       _appendDillForUri(dillTarget, patchedSdk.resolve('platform.dill'));
       final KernelTarget kernelTarget =
-          new KernelTarget(fileSystem, dillTarget, uriTranslator, strongMode);
+          new KernelTarget(fileSystem, dillTarget, uriTranslator);
       kernelTarget.read(fileName);
       await dillTarget.buildOutlines();
       await kernelTarget.buildOutlines();
-      coreTypes = kernelTarget.loader.coreTypes;
-      hierarchy = kernelTarget.loader.hierarchy;
       program = await kernelTarget.buildProgram();
       if (kernelTarget.errors.isNotEmpty) {
         return new CompilationResult.errors(kernelTarget.errors);
@@ -226,11 +220,6 @@ Future<CompilationResult> parseScriptInFileSystem(
       return new CompilationResult.error("No 'main' method found.");
     }
 
-    // Perform target-specific transformations.
-    Target target = getTarget("vm", new TargetFlags(strongMode: false));
-    target.performModularTransformations(coreTypes, hierarchy, program);
-    target.performGlobalTransformations(coreTypes, program);
-
     // Write the program to a list of bytes and return it.  Do not include
     // libraries that have a dart: import URI.
     //
@@ -249,9 +238,14 @@ Future<CompilationResult> parseScriptInFileSystem(
 }
 
 Future compilePlatform(Uri patchedSdk, Uri fullOutput,
-    {Uri outlineOutput, Uri packages, bool verbose: false}) async {
+    {Uri outlineOutput,
+    Uri packages,
+    bool verbose: false,
+    String backendTarget}) async {
+  backendTarget ??= "vm_fasta";
   Ticker ticker = new Ticker(isVerbose: verbose);
   await CompilerCommandLine.withGlobalOptions("", [""], (CompilerContext c) {
+    c.options.options["--target"] = backendTarget;
     c.options.options["--packages"] = packages;
     if (verbose) {
       c.options.options["--verbose"] = true;
@@ -268,7 +262,7 @@ Future writeDepsFile(Uri script, Uri depsFile, Uri output,
     Iterable<Uri> extraDependencies,
     bool verbose: false,
     String backendTarget}) async {
-  backendTarget ??= "vm";
+  backendTarget ??= "vm_fasta";
   Ticker ticker = new Ticker(isVerbose: verbose);
   await CompilerCommandLine.withGlobalOptions("", [""],
       (CompilerContext c) async {
@@ -281,11 +275,11 @@ Future writeDepsFile(Uri script, Uri depsFile, Uri output,
     TranslateUri uriTranslator = await TranslateUri.parse(c.fileSystem, sdk,
         packages: c.options.packages);
     ticker.logMs("Read packages file");
-    DillTarget dillTarget =
-        new DillTarget(ticker, uriTranslator, backendTarget);
+    DillTarget dillTarget = new DillTarget(ticker, uriTranslator, backendTarget,
+        flags: new TargetFlags(strongMode: false));
     _appendDillForUri(dillTarget, platform);
-    KernelTarget kernelTarget = new KernelTarget(PhysicalFileSystem.instance,
-        dillTarget, uriTranslator, false, c.uriToSource);
+    KernelTarget kernelTarget = new KernelTarget(
+        PhysicalFileSystem.instance, dillTarget, uriTranslator, c.uriToSource);
 
     kernelTarget.read(script);
     await dillTarget.buildOutlines();

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

@@ -40,12 +40,6 @@ import 'package:kernel/ast.dart'
         VariableGet,
         VoidType;
 
-import 'package:kernel/transformations/erasure.dart' show Erasure;
-
-import 'package:kernel/transformations/continuation.dart' as transformAsync;
-
-import 'package:kernel/transformations/mixin_full_resolution.dart' as mix;
-
 import 'package:kernel/type_algebra.dart' show substitute;
 
 import '../source/source_loader.dart' show SourceLoader;
@@ -89,8 +83,6 @@ class KernelTarget extends TargetImplementation {
   /// The [FileSystem] which should be used to access files.
   final FileSystem fileSystem;
 
-  final bool strongMode;
-
   final DillTarget dillTarget;
 
   /// Shared with [CompilerContext].
@@ -105,8 +97,10 @@ class KernelTarget extends TargetImplementation {
   final TypeBuilder dynamicType =
       new KernelNamedTypeBuilder("dynamic", null, -1, null);
 
-  KernelTarget(this.fileSystem, DillTarget dillTarget,
-      TranslateUri uriTranslator, this.strongMode,
+  bool get strongMode => backendTarget.strongMode;
+
+  KernelTarget(
+      this.fileSystem, DillTarget dillTarget, TranslateUri uriTranslator,
       [Map<String, Source> uriToSource])
       : dillTarget = dillTarget,
         uriToSource = uriToSource ?? CompilerContext.current.uriToSource,
@@ -655,27 +649,11 @@ class KernelTarget extends TargetImplementation {
   /// Run all transformations that are needed when building a program for the
   /// first time.
   void runBuildTransformations() {
-    transformMixinApplications();
-    otherTransformations();
-  }
-
-  void transformMixinApplications() {
-    mix.transformLibraries(
-        backendTarget, loader.coreTypes, loader.hierarchy, loader.libraries);
-    ticker.logMs("Transformed mixin applications");
-  }
-
-  void otherTransformations() {
-    if (!strongMode) {
-      // TODO(ahe): Don't generate type variables in the first place.
-      program.accept(new Erasure());
-      ticker.logMs("Erased type variables in generic methods");
-    }
-    if (errors.isEmpty && loader.collectCompileTimeErrors().isEmpty) {
-      // TODO(kmillikin): Make this run on a per-method basis.
-      transformAsync.transformLibraries(loader.coreTypes, loader.libraries);
-    }
-    ticker.logMs("Transformed async methods");
+    backendTarget.performModularTransformationsOnLibraries(
+        loader.coreTypes, loader.hierarchy, loader.libraries,
+        logger: (String msg) => ticker.logMs(msg));
+    backendTarget.performGlobalTransformations(loader.coreTypes, program,
+        logger: (String msg) => ticker.logMs(msg));
   }
 
   void verify() {

pkg/front_end/lib/src/incremental_kernel_generator_impl.dart

@@ -20,6 +20,7 @@ import 'package:front_end/src/incremental/file_state.dart';
 import 'package:kernel/binary/ast_from_binary.dart';
 import 'package:kernel/binary/limited_ast_to_binary.dart';
 import 'package:kernel/kernel.dart' hide Source;
+import 'package:kernel/target/targets.dart' show TargetFlags;
 
 dynamic unimplemented() {
   // TODO(paulberry): get rid of this.
@@ -100,8 +101,9 @@ class IncrementalKernelGeneratorImpl implements IncrementalKernelGenerator {
       });
 
       CanonicalName nameRoot = new CanonicalName.root();
-      DillTarget dillTarget =
-          new DillTarget(new Ticker(isVerbose: false), _uriTranslator, "vm");
+      DillTarget dillTarget = new DillTarget(
+          new Ticker(isVerbose: false), _uriTranslator, "vm_fasta",
+          flags: new TargetFlags(strongMode: _options.strongMode));
 
       List<_LibraryCycleResult> results = [];
       await _logger.runAsync('Compute results for cycles', () async {
@@ -204,8 +206,8 @@ class IncrementalKernelGeneratorImpl implements IncrementalKernelGenerator {
       }
 
       // Create KernelTarget and configure it for compiling the cycle URIs.
-      KernelTarget kernelTarget = new KernelTarget(_fsState.fileSystemView,
-          dillTarget, _uriTranslator, _options.strongMode);
+      KernelTarget kernelTarget =
+          new KernelTarget(_fsState.fileSystemView, dillTarget, _uriTranslator);
       for (FileState library in cycle.libraries) {
         kernelTarget.read(library.uri);
       }

pkg/front_end/test/fasta/shaker_test.dart

@@ -33,6 +33,7 @@ import 'package:front_end/src/fasta/translate_uri.dart' show TranslateUri;
 import 'package:front_end/src/fasta/util/relativize.dart' show relativizeUri;
 import 'package:kernel/ast.dart' show Program;
 import 'package:kernel/kernel.dart' show loadProgramFromBytes;
+import 'package:kernel/target/targets.dart' show TargetFlags;
 import 'package:testing/testing.dart'
     show Chain, ChainContext, ExpectationSet, Result, Step, TestDescription;
 import 'testing/suite.dart';
@@ -95,10 +96,11 @@ class BuildProgram
       var platformOutline = context.loadPlatformOutline();
       platformOutline.unbindCanonicalNames();
       var dillTarget = new DillTarget(
-          new Ticker(isVerbose: false), context.uriTranslator, "vm");
+          new Ticker(isVerbose: false), context.uriTranslator, "vm_fasta",
+          flags: new TargetFlags(strongMode: false));
       dillTarget.loader.appendLibraries(platformOutline);
-      var sourceTarget = new KernelTarget(PhysicalFileSystem.instance,
-          dillTarget, context.uriTranslator, false);
+      var sourceTarget = new KernelTarget(
+          PhysicalFileSystem.instance, dillTarget, context.uriTranslator);
       await dillTarget.buildOutlines();
 
       var inputUri = description.uri;
@@ -113,8 +115,8 @@ class BuildProgram
 
       /// This new KernelTarget contains only sources from the test without
       /// lib.dart.
-      sourceTarget = new KernelTarget(PhysicalFileSystem.instance, dillTarget,
-          context.uriTranslator, false);
+      sourceTarget = new KernelTarget(
+          PhysicalFileSystem.instance, dillTarget, context.uriTranslator);
 
       await dillTarget.buildOutlines();
       sourceTarget.read(inputUri);

pkg/front_end/test/fasta/testing/suite.dart

@@ -50,6 +50,8 @@ import 'package:front_end/src/fasta/dill/dill_target.dart' show DillTarget;
 
 import 'package:kernel/kernel.dart' show loadProgramFromBytes;
 
+import 'package:kernel/target/targets.dart' show TargetFlags;
+
 export 'package:testing/testing.dart' show Chain, runMe;
 
 const String STRONG_MODE = " strong mode ";
@@ -216,7 +218,9 @@ class Outline extends Step<TestDescription, Program, FastaContext> {
     CompilerContext.current.disableColors();
     Program platformOutline = await context.loadPlatformOutline();
     Ticker ticker = new Ticker();
-    DillTarget dillTarget = new DillTarget(ticker, context.uriTranslator, "vm");
+    DillTarget dillTarget = new DillTarget(
+        ticker, context.uriTranslator, "vm_fasta",
+        flags: new TargetFlags(strongMode: strongMode));
     platformOutline.unbindCanonicalNames();
     dillTarget.loader.appendLibraries(platformOutline);
     // We create a new URI translator to avoid reading plaform libraries from
@@ -228,7 +232,7 @@ class Outline extends Step<TestDescription, Program, FastaContext> {
     KernelTarget sourceTarget = astKind == AstKind.Analyzer
         ? new AnalyzerTarget(dillTarget, uriTranslator, strongMode)
         : new KernelTarget(
-            PhysicalFileSystem.instance, dillTarget, uriTranslator, strongMode);
+            PhysicalFileSystem.instance, dillTarget, uriTranslator);
 
     Program p;
     try {

pkg/front_end/tool/fasta_perf.dart

@@ -22,6 +22,7 @@ import 'package:front_end/src/fasta/translate_uri.dart' show TranslateUri;
 import 'package:front_end/src/fasta/translate_uri.dart';
 import 'package:front_end/src/fasta/parser/dart_vm_native.dart'
     show skipNativeClause;
+import 'package:kernel/target/targets.dart' show TargetFlags;
 
 /// Cumulative total number of chars scanned.
 int inputSize = 0;
@@ -214,9 +215,10 @@ generateKernel(Uri entryUri,
 
   var timer = new Stopwatch()..start();
   final Ticker ticker = new Ticker();
-  final DillTarget dillTarget = new DillTarget(ticker, uriResolver, "vm");
-  final KernelTarget kernelTarget = new KernelTarget(
-      PhysicalFileSystem.instance, dillTarget, uriResolver, strongMode);
+  final DillTarget dillTarget = new DillTarget(ticker, uriResolver, "vm_fasta",
+      flags: new TargetFlags(strongMode: strongMode));
+  final KernelTarget kernelTarget =
+      new KernelTarget(PhysicalFileSystem.instance, dillTarget, uriResolver);
   var entrypoints = [
     entryUri,
     // These extra libraries are added to match the same set of libraries

pkg/kernel/lib/target/flutter.dart

@@ -51,12 +51,14 @@ class FlutterTarget extends Target {
         'dart:vmservice_sky',
       ];
 
-  void performModularTransformations(
-      CoreTypes coreTypes, ClassHierarchy hierarchy, Program program) {
-    mix.transformLibraries(this, coreTypes, hierarchy, program.libraries);
+  void performModularTransformationsOnLibraries(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, List<Library> libraries,
+      {void logger(String msg)}) {
+    mix.transformLibraries(this, coreTypes, hierarchy, libraries);
   }
 
-  void performGlobalTransformations(CoreTypes coreTypes, Program program) {
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)}) {
     cont.transformProgram(coreTypes, program);
 
     // Repair `_getMainClosure()` function in dart:{_builtin,ui} libraries.

pkg/kernel/lib/target/targets.dart

@@ -7,10 +7,11 @@ import '../ast.dart';
 import '../class_hierarchy.dart';
 import '../core_types.dart';
 import '../transformations/treeshaker.dart' show ProgramRoot;
-import 'flutter.dart';
-import 'vm.dart';
-import 'vmcc.dart';
-import 'vmreify.dart';
+import 'flutter.dart' show FlutterTarget;
+import 'vm.dart' show VmTarget;
+import 'vm_fasta.dart' show VmFastaTarget;
+import 'vmcc.dart' show VmClosureConvertedTarget;
+import 'vmreify.dart' show VmGenericTypesReifiedTarget;
 
 final List<String> targetNames = targets.keys.toList();
 
@@ -32,6 +33,7 @@ typedef Target _TargetBuilder(TargetFlags flags);
 final Map<String, _TargetBuilder> targets = <String, _TargetBuilder>{
   'none': (TargetFlags flags) => new NoneTarget(flags),
   'vm': (TargetFlags flags) => new VmTarget(flags),
+  'vm_fasta': (TargetFlags flags) => new VmFastaTarget(flags),
   'vmcc': (TargetFlags flags) => new VmClosureConvertedTarget(flags),
   'vmreify': (TargetFlags flags) => new VmGenericTypesReifiedTarget(flags),
   'flutter': (TargetFlags flags) => new FlutterTarget(flags),
@@ -68,19 +70,47 @@ abstract class Target {
   /// If true, the SDK should be loaded in strong mode.
   bool get strongModeSdk => strongMode;
 
-  /// Perform target-specific modular transformations.
+  /// Perform target-specific modular transformations on the given program.
   ///
   /// These transformations should not be whole-program transformations.  They
   /// should expect that the program will contain external libraries.
-  void performModularTransformations(
-      CoreTypes coreTypes, ClassHierarchy hierarchy, Program program);
+  void performModularTransformationsOnProgram(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, Program program,
+      {void logger(String msg)}) {
+    performModularTransformationsOnLibraries(
+        coreTypes, hierarchy, program.libraries,
+        logger: logger);
+  }
+
+  /// Perform target-specific modular transformations on the given libraries.
+  ///
+  /// The intent of this method is to perform the transformations only on some
+  /// subset of the program libraries and avoid packing them into a temporary
+  /// [Program] instance to pass into [performModularTransformationsOnProgram].
+  ///
+  /// Note that the following should be equivalent:
+  ///
+  ///     target.performModularTransformationsOnProgram(coreTypes, program);
+  ///
+  /// and
+  ///
+  ///     target.performModularTransformationsOnLibraries(
+  ///         coreTypes, program.libraries);
+  void performModularTransformationsOnLibraries(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, List<Library> libraries,
+      {void logger(String msg)});
 
   /// Perform target-specific whole-program transformations.
   ///
   /// These transformations should be optimizations and not required for
   /// correctness.  Everything should work if a simple and fast linker chooses
   /// not to apply these transformations.
-  void performGlobalTransformations(CoreTypes coreTypes, Program program);
+  ///
+  /// Note that [performGlobalTransformations] doesn't have -OnProgram and
+  /// -OnLibraries alternatives, because the global knowledge required by the
+  /// transformations is assumed to be retrieved from a [Program] instance.
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)});
 
   /// Builds an expression that instantiates an [Invocation] that can be passed
   /// to [noSuchMethod].
@@ -98,9 +128,11 @@ class NoneTarget extends Target {
   bool get strongMode => flags.strongMode;
   String get name => 'none';
   List<String> get extraRequiredLibraries => <String>[];
-  void performModularTransformations(
-      CoreTypes coreTypes, ClassHierarchy hierarchy, Program program) {}
-  void performGlobalTransformations(CoreTypes coreTypes, Program program) {}
+  void performModularTransformationsOnLibraries(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, List<Library> libraries,
+      {void logger(String msg)}) {}
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)}) {}
 
   @override
   Expression instantiateInvocation(Member target, Expression receiver,

pkg/kernel/lib/target/vm.dart

@@ -56,15 +56,17 @@ class VmTarget extends Target {
 
   ClassHierarchy _hierarchy;
 
-  void performModularTransformations(
-      CoreTypes coreTypes, ClassHierarchy hierarchy, Program program) {
+  void performModularTransformationsOnLibraries(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, List<Library> libraries,
+      {void logger(String msg)}) {
     var mixins = new mix.MixinFullResolution(this, coreTypes, hierarchy)
-      ..transform(program.libraries);
+      ..transform(libraries);
 
     _hierarchy = mixins.hierarchy;
   }
 
-  void performGlobalTransformations(CoreTypes coreTypes, Program program) {
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)}) {
     if (strongMode) {
       new InsertTypeChecks(coreTypes, _hierarchy).transformProgram(program);
       new InsertCovarianceChecks(coreTypes, _hierarchy)

pkg/kernel/lib/target/vm_fasta.dart

@@ -0,0 +1,44 @@
+// Copyright (c) 2016, 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 kernel.target.vm_fasta;
+
+import '../ast.dart' show Program, Library;
+import '../core_types.dart' show CoreTypes;
+import '../class_hierarchy.dart' show ClassHierarchy;
+
+import '../transformations/mixin_full_resolution.dart' as transformMixins
+    show transformLibraries;
+import '../transformations/continuation.dart' as transformAsync
+    show transformLibraries;
+import '../transformations/erasure.dart' as tranformErasure
+    show transformLibraries;
+
+import 'targets.dart' show TargetFlags;
+import 'vm.dart' as vm_target;
+
+class VmFastaTarget extends vm_target.VmTarget {
+  VmFastaTarget(TargetFlags flags) : super(flags);
+
+  String get name => "vm_fasta";
+
+  void performModularTransformationsOnLibraries(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, List<Library> libraries,
+      {void logger(String msg)}) {
+    transformMixins.transformLibraries(this, coreTypes, hierarchy, libraries);
+    logger?.call("Transformed mixin applications");
+
+    // TODO(ahe): Don't generate type variables in the first place.
+    if (!strongMode) {
+      tranformErasure.transformLibraries(coreTypes, libraries);
+      logger?.call("Erased type variables in generic methods");
+    }
+
+    // TODO(kmillikin): Make this run on a per-method basis.
+    transformAsync.transformLibraries(coreTypes, libraries);
+    logger?.call("Transformed async methods");
+  }
+
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)}) {}
+}

pkg/kernel/lib/target/vmcc.dart

@@ -16,7 +16,8 @@ class VmClosureConvertedTarget extends vm_target.VmTarget {
   String get name => "vmcc";
 
   @override
-  void performGlobalTransformations(CoreTypes coreTypes, Program program) {
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)}) {
     super.performGlobalTransformations(coreTypes, program);
     cc.transformProgram(coreTypes, program);
   }

pkg/kernel/lib/target/vmreify.dart

@@ -27,7 +27,8 @@ class VmGenericTypesReifiedTarget extends vmcc_target.VmClosureConvertedTarget {
   }
 
   @override
-  void performGlobalTransformations(CoreTypes coreTypes, Program program) {
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)}) {
     super.performGlobalTransformations(coreTypes, program);
     // TODO(dmitryas) this transformation should be made modular
     reify.transformProgram(coreTypes, program);

pkg/kernel/lib/transformations/erasure.dart

@@ -5,6 +5,18 @@ library kernel.transformations.erasure;
 
 import '../ast.dart';
 import '../type_algebra.dart';
+import '../core_types.dart';
+
+Program transformProgram(CoreTypes coreTypes, Program program) {
+  program.accept(new Erasure());
+}
+
+void transformLibraries(CoreTypes coreTypes, List<Library> libraries) {
+  Erasure erasure = new Erasure();
+  for (Library library in libraries) {
+    library.accept(erasure);
+  }
+}
 
 /// This pass is a temporary measure to run strong mode code in the VM, which
 /// does not yet have the necessary runtime support.

pkg/kernel/test/baseline_tester.dart

@@ -27,10 +27,12 @@ abstract class TestTarget extends Target {
   Annotator get annotator => null;
 
   // Return a list of strings so that we can accumulate errors.
-  List<String> performModularTransformations(
-      CoreTypes coreTypes, ClassHierarchy hierarchy, Program program);
+  List<String> performModularTransformationsOnProgram(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, Program program,
+      {void logger(String msg)});
   List<String> performGlobalTransformations(
-      CoreTypes coreTypes, Program program);
+      CoreTypes coreTypes, Program program,
+      {void logger(String msg)});
 }
 
 void runBaselineTests(String folderName, TestTarget target) {
@@ -61,7 +63,7 @@ void runBaselineTests(String folderName, TestTarget target) {
         loader.loadProgram(dartPath, target: target);
         verifyProgram(program);
         var errors = <String>[];
-        errors.addAll(target.performModularTransformations(
+        errors.addAll(target.performModularTransformationsOnProgram(
             coreTypes, hierarchy, program));
         verifyProgram(program);
         errors.addAll(target.performGlobalTransformations(coreTypes, program));

pkg/kernel/test/closures/suite.dart

@@ -39,6 +39,8 @@ import 'package:front_end/src/fasta/testing/patched_sdk_location.dart';
 
 import 'package:kernel/kernel.dart' show loadProgramFromBinary;
 
+import 'package:kernel/target/targets.dart' show TargetFlags;
+
 const String STRONG_MODE = " strong mode ";
 
 class ClosureConversionContext extends ChainContext {
@@ -99,11 +101,13 @@ class FastaCompile
       TestDescription description, ClosureConversionContext context) async {
     Program platform = await context.loadPlatform();
     Ticker ticker = new Ticker();
-    DillTarget dillTarget = new DillTarget(ticker, context.uriTranslator, "vm");
+    DillTarget dillTarget = new DillTarget(
+        ticker, context.uriTranslator, "vm_fasta",
+        flags: new TargetFlags(strongMode: context.strongMode));
     platform.unbindCanonicalNames();
     dillTarget.loader.appendLibraries(platform);
-    KernelTarget sourceTarget = new KernelTarget(PhysicalFileSystem.instance,
-        dillTarget, context.uriTranslator, context.strongMode);
+    KernelTarget sourceTarget = new KernelTarget(
+        PhysicalFileSystem.instance, dillTarget, context.uriTranslator);
 
     Program p;
     try {

pkg/kernel/test/interpreter/suite.dart

@@ -35,6 +35,8 @@ import 'package:front_end/src/fasta/testing/patched_sdk_location.dart';
 
 import 'package:kernel/kernel.dart' show loadProgramFromBinary;
 
+import 'package:kernel/target/targets.dart' show TargetFlags;
+
 import 'package:kernel/interpreter/interpreter.dart';
 
 const String STRONG_MODE = " strong mode ";
@@ -80,11 +82,13 @@ class FastaCompile extends Step<TestDescription, Program, InterpreterContext> {
       TestDescription description, InterpreterContext context) async {
     Program platform = await context.loadPlatform();
     Ticker ticker = new Ticker();
-    DillTarget dillTarget = new DillTarget(ticker, context.uriTranslator, "vm");
+    DillTarget dillTarget = new DillTarget(
+        ticker, context.uriTranslator, "vm_fasta",
+        flags: new TargetFlags(strongMode: context.strongMode));
     platform.unbindCanonicalNames();
     dillTarget.loader.appendLibraries(platform);
-    KernelTarget sourceTarget = new KernelTarget(PhysicalFileSystem.instance,
-        dillTarget, context.uriTranslator, context.strongMode);
+    KernelTarget sourceTarget = new KernelTarget(
+        PhysicalFileSystem.instance, dillTarget, context.uriTranslator);
 
     Program p;
     try {

pkg/kernel/test/reify/suite.dart

@@ -198,7 +198,7 @@ class NotReifiedKernel extends Step<TestDescription, Program, TestContext> {
       var coreTypes = new CoreTypes(program);
       var hierarchy = new ClosedWorldClassHierarchy(program);
       target
-        ..performModularTransformations(coreTypes, hierarchy, program)
+        ..performModularTransformationsOnProgram(coreTypes, hierarchy, program)
         ..performGlobalTransformations(coreTypes, program);
       return pass(program);
     } catch (e, s) {

pkg/kernel/tool/dartk.dart

@@ -409,7 +409,8 @@ Future<CompilerOutcome> batchMain(
   if (target != null && canContinueCompilation) {
     CoreTypes coreTypes = new CoreTypes(program);
     ClassHierarchy hierarchy = new ClosedWorldClassHierarchy(program);
-    target.performModularTransformations(coreTypes, hierarchy, program);
+    target.performModularTransformationsOnProgram(
+        coreTypes, hierarchy, program);
     runVerifier();
     if (options['link']) {
       target.performGlobalTransformations(coreTypes, program);