diff --git a/build.gradle b/build.gradle
index 7720cf3..7f41caa 100644
--- a/build.gradle
+++ b/build.gradle
@@ -61,7 +61,10 @@
     '-Xep:MissingDefault:ERROR',
     '-Xep:MultipleTopLevelClasses:ERROR',
     '-Xep:NarrowingCompoundAssignment:ERROR',
-    '-Xep:BoxedPrimitiveConstructor:ERROR']
+    '-Xep:BoxedPrimitiveConstructor:ERROR',
+    '-Xep:LogicalAssignment:ERROR',
+    '-Xep:FloatCast:ERROR',
+    '-Xep:ReturnValueIgnored:ERROR']
 
 apply from: 'copyAdditionalJctfCommonFiles.gradle'
 
diff --git a/src/main/java/com/android/tools/r8/Disassemble.java b/src/main/java/com/android/tools/r8/Disassemble.java
index 9b1599f..7b17ec8 100644
--- a/src/main/java/com/android/tools/r8/Disassemble.java
+++ b/src/main/java/com/android/tools/r8/Disassemble.java
@@ -14,7 +14,6 @@
 import com.android.tools.r8.utils.StringDiagnostic;
 import com.android.tools.r8.utils.ThreadUtils;
 import com.android.tools.r8.utils.Timing;
-import com.google.common.collect.ImmutableList;
 import java.io.IOException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -33,6 +32,7 @@
       private Path proguardMapFile = null;
       private boolean useSmali = false;
       private boolean allInfo = false;
+      private boolean useIr;
 
       @Override
       Builder self() {
@@ -63,6 +63,11 @@
         return this;
       }
 
+      public Builder setUseIr(boolean useIr) {
+        this.useIr = useIr;
+        return this;
+      }
+
       @Override
       protected DisassembleCommand makeCommand() {
         // If printing versions ignore everything else.
@@ -74,24 +79,26 @@
             getOutputPath(),
             proguardMapFile == null ? null : StringResource.fromFile(proguardMapFile),
             allInfo,
-            useSmali);
+            useSmali,
+            useIr);
       }
     }
 
-    static final String USAGE_MESSAGE = String.join("\n", ImmutableList.of(
-        "Usage: disasm [options] <input-files>",
-        " where <input-files> are dex files",
-        " and options are:",
-        "  --all                   # Include all information in disassembly.",
-        "  --smali                 # Disassemble using smali syntax.",
-        "  --pg-map <file>         # Proguard map <file> for mapping names.",
-        "  --output                # Specify a file or directory to write to.",
-        "  --version               # Print the version of r8.",
-        "  --help                  # Print this message."));
-
+    static final String USAGE_MESSAGE =
+        "Usage: disasm [options] <input-files>\n"
+            + " where <input-files> are dex files\n"
+            + " and options are:\n"
+            + "  --all                   # Include all information in disassembly.\n"
+            + "  --smali                 # Disassemble using smali syntax.\n"
+            + "  --ir                    # Print IR before and after optimization.\n"
+            + "  --pg-map <file>         # Proguard map <file> for mapping names.\n"
+            + "  --output                # Specify a file or directory to write to.\n"
+            + "  --version               # Print the version of r8.\n"
+            + "  --help                  # Print this message.";
 
     private final boolean allInfo;
     private final boolean useSmali;
+    private final boolean useIr;
 
     public static Builder builder() {
       return new Builder();
@@ -112,10 +119,12 @@
           builder.setPrintHelp(true);
         } else if (arg.equals("--version")) {
           builder.setPrintVersion(true);
-          } else if (arg.equals("--all")) {
+        } else if (arg.equals("--all")) {
           builder.setAllInfo(true);
         } else if (arg.equals("--smali")) {
           builder.setUseSmali(true);
+        } else if (arg.equals("--ir")) {
+          builder.setUseIr(true);
         } else if (arg.equals("--pg-map")) {
           builder.setProguardMapFile(Paths.get(args[++i]));
         } else if (arg.equals("--output")) {
@@ -132,13 +141,18 @@
     }
 
     private DisassembleCommand(
-        AndroidApp inputApp, Path outputPath, StringResource proguardMap,
-        boolean allInfo, boolean useSmali) {
+        AndroidApp inputApp,
+        Path outputPath,
+        StringResource proguardMap,
+        boolean allInfo,
+        boolean useSmali,
+        boolean useIr) {
       super(inputApp);
       this.outputPath = outputPath;
       this.proguardMap = proguardMap;
       this.allInfo = allInfo;
       this.useSmali = useSmali;
+      this.useIr = useIr;
     }
 
     private DisassembleCommand(boolean printHelp, boolean printVersion) {
@@ -147,6 +161,7 @@
       proguardMap = null;
       allInfo = false;
       useSmali = false;
+      useIr = false;
     }
 
     public Path getOutputPath() {
@@ -157,6 +172,10 @@
       return useSmali;
     }
 
+    public boolean useIr() {
+      return useIr;
+    }
+
     @Override
     InternalOptions getInternalOptions() {
       InternalOptions internal = new InternalOptions();
@@ -190,9 +209,10 @@
     try {
       DexApplication application =
           new ApplicationReader(app, options, timing).read(command.proguardMap, executor);
-      DexByteCodeWriter writer = command.useSmali()
-          ? new SmaliWriter(application, options)
-          : new AssemblyWriter(application, options, command.allInfo);
+      DexByteCodeWriter writer =
+          command.useSmali()
+              ? new SmaliWriter(application, options)
+              : new AssemblyWriter(application, options, command.allInfo, command.useIr());
       if (command.getOutputPath() != null) {
         writer.write(command.getOutputPath());
       } else {
diff --git a/src/main/java/com/android/tools/r8/JarSizeCompare.java b/src/main/java/com/android/tools/r8/JarSizeCompare.java
new file mode 100644
index 0000000..aa16b1f
--- /dev/null
+++ b/src/main/java/com/android/tools/r8/JarSizeCompare.java
@@ -0,0 +1,482 @@
+// Copyright (c) 2018, the R8 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.
+package com.android.tools.r8;
+
+import com.android.tools.r8.dex.ApplicationReader;
+import com.android.tools.r8.errors.Unreachable;
+import com.android.tools.r8.graph.Code;
+import com.android.tools.r8.graph.DexApplication;
+import com.android.tools.r8.graph.DexClass;
+import com.android.tools.r8.graph.DexEncodedField;
+import com.android.tools.r8.graph.DexEncodedMethod;
+import com.android.tools.r8.graph.DexProgramClass;
+import com.android.tools.r8.naming.ClassNameMapper;
+import com.android.tools.r8.naming.ClassNamingForNameMapper;
+import com.android.tools.r8.naming.MemberNaming.FieldSignature;
+import com.android.tools.r8.naming.MemberNaming.MethodSignature;
+import com.android.tools.r8.utils.AndroidApiLevel;
+import com.android.tools.r8.utils.AndroidApp;
+import com.android.tools.r8.utils.AndroidAppConsumers;
+import com.android.tools.r8.utils.DescriptorUtils;
+import com.android.tools.r8.utils.InternalOptions;
+import com.android.tools.r8.utils.Timing;
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableMap;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.function.BiConsumer;
+
+/**
+ * JarSizeCompare outputs the class, method, field sizes of the given JAR files. For each input, a
+ * ProGuard map can be passed that is used to resolve minified names.
+ *
+ * <p>By default, only shows methods where R8's DEX output is 5 or more instructions larger than
+ * ProGuard+D8's output. Pass {@code --threshold 0} to display all methods.
+ */
+public class JarSizeCompare {
+
+  private static final String USAGE =
+      "Arguments:\n"
+          + "    [--threshold <threshold>]\n"
+          + "    [--lib <lib.jar>]\n"
+          + "    --input <name1> <input1.jar> [<map1.txt>]\n"
+          + "    --input <name2> <input2.jar> [<map2.txt>] ...\n"
+          + "\n"
+          + "JarSizeCompare outputs the class, method, field sizes of the given JAR files.\n"
+          + "For each input, a ProGuard map can be passed that is used to resolve minified names.\n";
+
+  private static final ImmutableMap<String, String> R8_RELOCATIONS =
+      ImmutableMap.<String, String>builder()
+          .put("com.google.common", "com.android.tools.r8.com.google.common")
+          .put("com.google.gson", "com.android.tools.r8.com.google.gson")
+          .put("com.google.thirdparty", "com.android.tools.r8.com.google.thirdparty")
+          .put("joptsimple", "com.android.tools.r8.joptsimple")
+          .put("org.apache.commons", "com.android.tools.r8.org.apache.commons")
+          .put("org.objectweb.asm", "com.android.tools.r8.org.objectweb.asm")
+          .put("it.unimi.dsi.fastutil", "com.android.tools.r8.it.unimi.dsi.fastutil")
+          .build();
+
+  private final List<Path> libraries;
+  private final List<InputParameter> inputParameters;
+  private final int threshold;
+  private final InternalOptions options;
+  private int pgIndex;
+  private int r8Index;
+
+  private JarSizeCompare(
+      List<Path> libraries, List<InputParameter> inputParameters, int threshold) {
+    this.libraries = libraries;
+    this.inputParameters = inputParameters;
+    this.threshold = threshold;
+    options = new InternalOptions();
+    options.enableCfFrontend = true;
+  }
+
+  public void run() throws Exception {
+    List<String> names = new ArrayList<>();
+    List<InputApplication> inputApplicationList = new ArrayList<>();
+    Timing timing = new Timing("JarSizeCompare");
+    for (InputParameter inputParameter : inputParameters) {
+      AndroidApp inputApp = inputParameter.getInputApp(libraries);
+      DexApplication input = inputParameter.getReader(options, inputApp, timing);
+      AndroidAppConsumers appConsumer = new AndroidAppConsumers();
+      D8.run(
+          D8Command.builder(inputApp)
+              .setMinApiLevel(AndroidApiLevel.P.getLevel())
+              .setProgramConsumer(appConsumer.wrapDexIndexedConsumer(null))
+              .build());
+      DexApplication d8Input = inputParameter.getReader(options, appConsumer.build(), timing);
+      InputApplication inputApplication =
+          new InputApplication(input, translateClassNames(input, input.classes()));
+      InputApplication d8Classes =
+          new InputApplication(input, translateClassNames(input, d8Input.classes()));
+      names.add(inputParameter.name + "-input");
+      inputApplicationList.add(inputApplication);
+      names.add(inputParameter.name + "-d8");
+      inputApplicationList.add(d8Classes);
+    }
+    if (threshold != 0) {
+      pgIndex = names.indexOf("pg-d8");
+      r8Index = names.indexOf("r8-d8");
+    }
+    Map<String, InputClass[]> inputClasses = new HashMap<>();
+    for (int i = 0; i < names.size(); i++) {
+      InputApplication classes = inputApplicationList.get(i);
+      for (String className : classes.getClasses()) {
+        inputClasses.computeIfAbsent(className, k -> new InputClass[names.size()])[i] =
+            classes.getInputClass(className);
+      }
+    }
+    for (Entry<String, Map<String, InputClass[]>> library : byLibrary(inputClasses)) {
+      System.out.println("");
+      System.out.println(Strings.repeat("=", 100));
+      String commonPrefix = getCommonPrefix(library.getValue().keySet());
+      if (library.getKey().isEmpty()) {
+        System.out.println("PROGRAM (" + commonPrefix + ")");
+      } else {
+        System.out.println("LIBRARY: " + library.getKey() + " (" + commonPrefix + ")");
+      }
+      printLibrary(library.getValue(), commonPrefix);
+    }
+  }
+
+  private Map<String, DexProgramClass> translateClassNames(
+      DexApplication input, List<DexProgramClass> classes) {
+    Map<String, DexProgramClass> result = new HashMap<>();
+    ClassNameMapper classNameMapper = input.getProguardMap();
+    for (DexProgramClass programClass : classes) {
+      ClassNamingForNameMapper classNaming;
+      if (classNameMapper == null) {
+        classNaming = null;
+      } else {
+        classNaming = classNameMapper.getClassNaming(programClass.type);
+      }
+      String type =
+          classNaming == null ? programClass.type.toSourceString() : classNaming.originalName;
+      result.put(type, programClass);
+    }
+    return result;
+  }
+
+  private String getCommonPrefix(Set<String> classes) {
+    if (classes.size() <= 1) {
+      return "";
+    }
+    String commonPrefix = null;
+    for (String clazz : classes) {
+      if (clazz.equals("r8.GeneratedOutlineSupport")) {
+        continue;
+      }
+      if (commonPrefix == null) {
+        commonPrefix = clazz;
+      } else {
+        int i = 0;
+        while (i < clazz.length()
+            && i < commonPrefix.length()
+            && clazz.charAt(i) == commonPrefix.charAt(i)) {
+          i++;
+        }
+        commonPrefix = commonPrefix.substring(0, i);
+      }
+    }
+    return commonPrefix;
+  }
+
+  private void printLibrary(Map<String, InputClass[]> classMap, String commonPrefix) {
+    List<Entry<String, InputClass[]>> classes = new ArrayList<>(classMap.entrySet());
+    classes.sort(Comparator.comparing(Entry::getKey));
+    for (Entry<String, InputClass[]> clazz : classes) {
+      printClass(
+          clazz.getKey().substring(commonPrefix.length()), new ClassCompare(clazz.getValue()));
+    }
+  }
+
+  private void printClass(String name, ClassCompare inputClasses) {
+    List<MethodSignature> methods = getMethods(inputClasses);
+    List<FieldSignature> fields = getFields(inputClasses);
+    if (methods.isEmpty() && fields.isEmpty()) {
+      return;
+    }
+    System.out.println(name);
+    for (MethodSignature sig : methods) {
+      printSignature(getMethodString(sig), inputClasses.sizes(sig));
+    }
+    for (FieldSignature sig : fields) {
+      printSignature(getFieldString(sig), inputClasses.sizes(sig));
+    }
+  }
+
+  private String getMethodString(MethodSignature sig) {
+    StringBuilder builder = new StringBuilder().append('(');
+    for (int i = 0; i < sig.parameters.length; i++) {
+      builder.append(DescriptorUtils.javaTypeToShorty(sig.parameters[i]));
+    }
+    builder.append(')').append(DescriptorUtils.javaTypeToShorty(sig.type)).append(' ');
+    return builder.append(sig.name).toString();
+  }
+
+  private String getFieldString(FieldSignature sig) {
+    return DescriptorUtils.javaTypeToShorty(sig.type) + ' ' + sig.name;
+  }
+
+  private void printSignature(String key, int[] sizes) {
+    System.out.print(padItem(key));
+    for (int size : sizes) {
+      System.out.print(padValue(size));
+    }
+    System.out.print('\n');
+  }
+
+  private List<MethodSignature> getMethods(ClassCompare inputClasses) {
+    List<MethodSignature> methods = new ArrayList<>();
+    for (MethodSignature methodSignature : inputClasses.getMethods()) {
+      if (threshold == 0 || methodExceedsThreshold(inputClasses, methodSignature)) {
+        methods.add(methodSignature);
+      }
+    }
+    return methods;
+  }
+
+  private boolean methodExceedsThreshold(
+      ClassCompare inputClasses, MethodSignature methodSignature) {
+    assert threshold > 0;
+    assert pgIndex != r8Index;
+    int pgSize = inputClasses.size(methodSignature, pgIndex);
+    int r8Size = inputClasses.size(methodSignature, r8Index);
+    return pgSize != -1 && r8Size != -1 && pgSize + threshold <= r8Size;
+  }
+
+  private List<FieldSignature> getFields(ClassCompare inputClasses) {
+    return threshold == 0 ? inputClasses.getFields() : Collections.emptyList();
+  }
+
+  private String padItem(String s) {
+    return String.format("%-52s", s);
+  }
+
+  private String padValue(int v) {
+    return String.format("%8s", v == -1 ? "---" : v);
+  }
+
+  private List<Map.Entry<String, Map<String, InputClass[]>>> byLibrary(
+      Map<String, InputClass[]> inputClasses) {
+    Map<String, Map<String, InputClass[]>> byLibrary = new HashMap<>();
+    for (Entry<String, InputClass[]> entry : inputClasses.entrySet()) {
+      Map<String, InputClass[]> library =
+          byLibrary.computeIfAbsent(getLibraryName(entry.getKey()), k -> new HashMap<>());
+      library.put(entry.getKey(), entry.getValue());
+    }
+    List<Entry<String, Map<String, InputClass[]>>> list = new ArrayList<>(byLibrary.entrySet());
+    list.sort(Comparator.comparing(Entry::getKey));
+    return list;
+  }
+
+  private String getLibraryName(String className) {
+    for (Entry<String, String> relocation : R8_RELOCATIONS.entrySet()) {
+      if (className.startsWith(relocation.getValue())) {
+        return relocation.getKey();
+      }
+    }
+    return "";
+  }
+
+  static class InputParameter {
+
+    private final String name;
+    private final Path jar;
+    private final Path map;
+
+    InputParameter(String name, Path jar, Path map) {
+      this.name = name;
+      this.jar = jar;
+      this.map = map;
+    }
+
+    DexApplication getReader(InternalOptions options, AndroidApp inputApp, Timing timing)
+        throws Exception {
+      ApplicationReader applicationReader = new ApplicationReader(inputApp, options, timing);
+      return applicationReader.read(map == null ? null : StringResource.fromFile(map)).toDirect();
+    }
+
+    AndroidApp getInputApp(List<Path> libraries) throws Exception {
+      return AndroidApp.builder().addLibraryFiles(libraries).addProgramFiles(jar).build();
+    }
+  }
+
+  static class InputApplication {
+
+    private final DexApplication dexApplication;
+    private final Map<String, DexProgramClass> classMap;
+
+    private InputApplication(DexApplication dexApplication, Map<String, DexProgramClass> classMap) {
+      this.dexApplication = dexApplication;
+      this.classMap = classMap;
+    }
+
+    public Set<String> getClasses() {
+      return classMap.keySet();
+    }
+
+    private InputClass getInputClass(String type) {
+      DexProgramClass inputClass = classMap.get(type);
+      ClassNameMapper proguardMap = dexApplication.getProguardMap();
+      return new InputClass(inputClass, proguardMap);
+    }
+  }
+
+  static class InputClass {
+    private final DexProgramClass programClass;
+    private final ClassNameMapper proguardMap;
+
+    InputClass(DexClass dexClass, ClassNameMapper proguardMap) {
+      this.programClass = dexClass == null ? null : dexClass.asProgramClass();
+      this.proguardMap = proguardMap;
+    }
+
+    void forEachMethod(BiConsumer<MethodSignature, DexEncodedMethod> consumer) {
+      if (programClass == null) {
+        return;
+      }
+      programClass.forEachMethod(
+          dexEncodedMethod -> {
+            MethodSignature originalSignature =
+                proguardMap == null
+                    ? null
+                    : ((MethodSignature) proguardMap.originalSignatureOf(dexEncodedMethod.method));
+            MethodSignature signature = MethodSignature.fromDexMethod(dexEncodedMethod.method);
+            consumer.accept(
+                originalSignature == null ? signature : originalSignature, dexEncodedMethod);
+          });
+    }
+
+    void forEachField(BiConsumer<FieldSignature, DexEncodedField> consumer) {
+      if (programClass == null) {
+        return;
+      }
+      programClass.forEachField(
+          dexEncodedField -> {
+            FieldSignature originalSignature =
+                proguardMap == null ? null : proguardMap.originalSignatureOf(dexEncodedField.field);
+            FieldSignature signature = FieldSignature.fromDexField(dexEncodedField.field);
+            consumer.accept(
+                originalSignature == null ? signature : originalSignature, dexEncodedField);
+          });
+    }
+  }
+
+  private static class ClassCompare {
+    final Map<MethodSignature, DexEncodedMethod[]> methods = new HashMap<>();
+    final Map<FieldSignature, DexEncodedField[]> fields = new HashMap<>();
+    final int classes;
+
+    ClassCompare(InputClass[] inputs) {
+      for (int i = 0; i < inputs.length; i++) {
+        InputClass inputClass = inputs[i];
+        int finalI = i;
+        if (inputClass == null) {
+          continue;
+        }
+        inputClass.forEachMethod(
+            (sig, m) ->
+                methods.computeIfAbsent(sig, o -> new DexEncodedMethod[inputs.length])[finalI] = m);
+        inputClass.forEachField(
+            (sig, f) ->
+                fields.computeIfAbsent(sig, o -> new DexEncodedField[inputs.length])[finalI] = f);
+      }
+      classes = inputs.length;
+    }
+
+    List<MethodSignature> getMethods() {
+      List<MethodSignature> methods = new ArrayList<>(this.methods.keySet());
+      methods.sort(Comparator.comparing(MethodSignature::toString));
+      return methods;
+    }
+
+    List<FieldSignature> getFields() {
+      List<FieldSignature> fields = new ArrayList<>(this.fields.keySet());
+      fields.sort(Comparator.comparing(FieldSignature::toString));
+      return fields;
+    }
+
+    int size(MethodSignature method, int classIndex) {
+      DexEncodedMethod dexEncodedMethod = methods.get(method)[classIndex];
+      if (dexEncodedMethod == null) {
+        return -1;
+      }
+      Code code = dexEncodedMethod.getCode();
+      if (code == null) {
+        return 0;
+      }
+      if (code.isCfCode()) {
+        return code.asCfCode().getInstructions().size();
+      }
+      if (code.isDexCode()) {
+        return code.asDexCode().instructions.length;
+      }
+      throw new Unreachable();
+    }
+
+    int[] sizes(MethodSignature method) {
+      int[] result = new int[classes];
+      for (int i = 0; i < classes; i++) {
+        result[i] = size(method, i);
+      }
+      return result;
+    }
+
+    int size(FieldSignature field, int classIndex) {
+      return fields.get(field)[classIndex] == null ? -1 : 1;
+    }
+
+    int[] sizes(FieldSignature field) {
+      int[] result = new int[classes];
+      for (int i = 0; i < classes; i++) {
+        result[i] = size(field, i);
+      }
+      return result;
+    }
+  }
+
+  public static void main(String[] args) throws Exception {
+    JarSizeCompare program = JarSizeCompare.parse(args);
+    if (program == null) {
+      System.out.println(USAGE);
+    } else {
+      program.run();
+    }
+  }
+
+  public static JarSizeCompare parse(String[] args) {
+    int i = 0;
+    int threshold = 0;
+    List<Path> libraries = new ArrayList<>();
+    List<InputParameter> inputs = new ArrayList<>();
+    Set<String> names = new HashSet<>();
+    while (i < args.length) {
+      if (args[i].equals("--threshold") && i + 1 < args.length) {
+        threshold = Integer.parseInt(args[i + 1]);
+        i += 2;
+      } else if (args[i].equals("--lib") && i + 1 < args.length) {
+        libraries.add(Paths.get(args[i + 1]));
+        i += 2;
+      } else if (args[i].equals("--input") && i + 2 < args.length) {
+        String name = args[i + 1];
+        Path jar = Paths.get(args[i + 2]);
+        Path map = null;
+        if (i + 3 < args.length && !args[i + 3].startsWith("-")) {
+          map = Paths.get(args[i + 3]);
+          i += 4;
+        } else {
+          i += 3;
+        }
+        inputs.add(new InputParameter(name, jar, map));
+        if (!names.add(name)) {
+          System.out.println("Duplicate name: " + name);
+          return null;
+        }
+      } else {
+        return null;
+      }
+    }
+    if (inputs.size() < 2) {
+      return null;
+    }
+    if (threshold != 0 && (!names.contains("r8") || !names.contains("pg"))) {
+      System.out.println(
+          "You must either specify names \"pg\" and \"r8\" for input files "
+              + "or use \"--threshold 0\".");
+      return null;
+    }
+    return new JarSizeCompare(libraries, inputs, threshold);
+  }
+}
diff --git a/src/main/java/com/android/tools/r8/SwissArmyKnife.java b/src/main/java/com/android/tools/r8/SwissArmyKnife.java
index 28e1f93..f54233b 100644
--- a/src/main/java/com/android/tools/r8/SwissArmyKnife.java
+++ b/src/main/java/com/android/tools/r8/SwissArmyKnife.java
@@ -61,6 +61,9 @@
       case "jardiff":
         JarDiff.main(shift(args));
         break;
+      case "jarsizecompare":
+        JarSizeCompare.main(shift(args));
+        break;
       case "maindex":
         GenerateMainDexList.main(shift(args));
         break;
diff --git a/src/main/java/com/android/tools/r8/UsageInformationConsumer.java b/src/main/java/com/android/tools/r8/UsageInformationConsumer.java
deleted file mode 100644
index a572908..0000000
--- a/src/main/java/com/android/tools/r8/UsageInformationConsumer.java
+++ /dev/null
@@ -1,133 +0,0 @@
-// Copyright (c) 2017, the R8 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.
-package com.android.tools.r8;
-
-import com.android.tools.r8.origin.Origin;
-import com.android.tools.r8.origin.PathOrigin;
-import com.android.tools.r8.utils.ExceptionDiagnostic;
-import com.android.tools.r8.utils.FileUtils;
-import java.io.IOException;
-import java.io.OutputStream;
-import java.nio.file.Path;
-
-/**
- * Interface for receiving usage feedback from R8.
- *
- * The data is in the format defined for Proguard's <code>-printusage</code> flag. The information
- * will be produced if a consumer is provided. A consumer is automatically setup when running R8
- * with the Proguard <code>-printusage</code> flag set.
- */
-public interface UsageInformationConsumer {
-
-  /**
-   * Callback to receive the usage-information data.
-   *
-   * <p>The consumer is expected not to throw, but instead report any errors via the diagnostics
-   * {@param handler}. If an error is reported via {@param handler} and no exceptions are thrown,
-   * then the compiler guaranties to exit with an error.
-   *
-   * @param data UTF-8 encoded usage information.
-   * @param handler Diagnostics handler for reporting.
-   */
-  void acceptUsageInformation(byte[] data, DiagnosticsHandler handler);
-
-  static EmptyConsumer emptyConsumer() {
-    return EmptyConsumer.EMPTY_CONSUMER;
-  }
-
-  /** Empty consumer to request usage information but ignore the result. */
-  class EmptyConsumer implements UsageInformationConsumer {
-
-    private static final EmptyConsumer EMPTY_CONSUMER = new EmptyConsumer();
-
-    private EmptyConsumer() {}
-
-    @Override
-    public void acceptUsageInformation(byte[] data, DiagnosticsHandler handler) {
-      // Ignore content.
-    }
-  }
-
-    /** Forwarding consumer to delegate to an optional existing consumer. */
-  class ForwardingConsumer implements UsageInformationConsumer {
-
-    private final UsageInformationConsumer consumer;
-
-    /** @param consumer Consumer to forward to, if null, nothing will be forwarded. */
-    public ForwardingConsumer(UsageInformationConsumer consumer) {
-      this.consumer = consumer;
-    }
-
-    @Override
-    public void acceptUsageInformation(byte[] data, DiagnosticsHandler handler) {
-      if (consumer != null) {
-        consumer.acceptUsageInformation(data, handler);
-      }
-    }
-  }
-
-  /** File consumer to write contents to a file-system file. */
-  class FileConsumer extends ForwardingConsumer {
-
-    private final Path outputPath;
-
-    /** Consumer that writes to {@param outputPath}. */
-    public FileConsumer(Path outputPath) {
-      this(outputPath, null);
-    }
-
-    /** Consumer that forwards to {@param consumer} and also writes to {@param outputPath}. */
-    public FileConsumer(Path outputPath, UsageInformationConsumer consumer) {
-      super(consumer);
-      this.outputPath = outputPath;
-    }
-
-    @Override
-    public void acceptUsageInformation(byte[] data, DiagnosticsHandler handler) {
-      super.acceptUsageInformation(data, handler);
-      try {
-        FileUtils.writeToFile(outputPath, null, data);
-      } catch (IOException e) {
-        Origin origin = new PathOrigin(outputPath);
-        handler.error(new ExceptionDiagnostic(e, origin));
-      }
-    }
-  }
-
-  /**
-   * Stream consumer to write contents to an output stream.
-   *
-   * <p>Note: No close events are given to this stream so it should either be a permanent stream or
-   * the closing needs to happen outside of the compilation itself. If the stream is not one of the
-   * standard streams, i.e., System.out or System.err, you should likely implement yor own consumer.
-   */
-  class StreamConsumer extends ForwardingConsumer {
-
-    private final Origin origin;
-    private final OutputStream outputStream;
-
-    /** Consumer that writes to {@param outputStream}. */
-    public StreamConsumer(Origin origin, OutputStream outputStream) {
-      this(origin, outputStream, null);
-    }
-
-    /** Consumer that forwards to {@param consumer} and also writes to {@param outputStream}. */
-    public StreamConsumer(
-        Origin origin, OutputStream outputStream, UsageInformationConsumer consumer) {
-      super(consumer);
-      this.origin = origin;
-      this.outputStream = outputStream;
-    }
-
-    @Override
-    public void acceptUsageInformation(byte[] data, DiagnosticsHandler handler) {
-      super.acceptUsageInformation(data, handler);
-      try {
-        outputStream.write(data);
-      } catch (IOException e) {
-        handler.error(new ExceptionDiagnostic(e, origin));
-      }
-    }
-  }
-}
diff --git a/src/main/java/com/android/tools/r8/graph/AssemblyWriter.java b/src/main/java/com/android/tools/r8/graph/AssemblyWriter.java
index 89abadd..23dbfbf 100644
--- a/src/main/java/com/android/tools/r8/graph/AssemblyWriter.java
+++ b/src/main/java/com/android/tools/r8/graph/AssemblyWriter.java
@@ -3,9 +3,15 @@
 // BSD-style license that can be found in the LICENSE file.
 package com.android.tools.r8.graph;
 
+import com.android.tools.r8.ClassFileConsumer;
+import com.android.tools.r8.ir.conversion.IRConverter;
+import com.android.tools.r8.ir.conversion.OptimizationFeedback;
+import com.android.tools.r8.ir.conversion.OptimizationFeedbackIgnore;
 import com.android.tools.r8.naming.ClassNameMapper;
 import com.android.tools.r8.naming.MemberNaming.FieldSignature;
+import com.android.tools.r8.utils.CfgPrinter;
 import com.android.tools.r8.utils.InternalOptions;
+import com.android.tools.r8.utils.Timing;
 import java.io.PrintStream;
 
 public class AssemblyWriter extends DexByteCodeWriter {
@@ -13,12 +19,29 @@
   private final boolean writeAllClassInfo;
   private final boolean writeFields;
   private final boolean writeAnnotations;
+  private final boolean writeIR;
+  private final AppInfoWithSubtyping appInfo;
+  private final Timing timing = new Timing("AssemblyWriter");
+  private final OptimizationFeedback ignoreOptimizationFeedback = new OptimizationFeedbackIgnore();
 
-  public AssemblyWriter(DexApplication application, InternalOptions options, boolean allInfo) {
+  public AssemblyWriter(
+      DexApplication application, InternalOptions options, boolean allInfo, boolean writeIR) {
     super(application, options);
     this.writeAllClassInfo = allInfo;
     this.writeFields = allInfo;
     this.writeAnnotations = allInfo;
+    this.writeIR = writeIR;
+    if (writeIR) {
+      this.appInfo = new AppInfoWithSubtyping(application.toDirect());
+      if (options.programConsumer == null) {
+        // Use class-file backend, since the CF frontend for testing does not support desugaring of
+        // synchronized methods for the DEX backend (b/109789541).
+        options.programConsumer = ClassFileConsumer.emptyConsumer();
+      }
+      options.outline.enabled = false;
+    } else {
+      this.appInfo = null;
+    }
   }
 
   @Override
@@ -88,10 +111,21 @@
     ps.println();
     Code code = method.getCode();
     if (code != null) {
-      ps.println(code.toString(method, naming));
+      if (writeIR) {
+        writeIR(method, ps);
+      } else {
+        ps.println(code.toString(method, naming));
+      }
     }
   }
 
+  private void writeIR(DexEncodedMethod method, PrintStream ps) {
+    CfgPrinter printer = new CfgPrinter();
+    new IRConverter(appInfo, options, timing, printer)
+        .processMethod(method, ignoreOptimizationFeedback, null, null, null);
+    ps.println(printer.toString());
+  }
+
   private void writeAnnotations(DexAnnotationSet annotations, PrintStream ps) {
     if (writeAnnotations) {
       if (!annotations.isEmpty()) {
diff --git a/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java b/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java
index 831edbe..5f0fb83 100644
--- a/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java
+++ b/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java
@@ -264,9 +264,10 @@
 
   public void setCode(
       IRCode ir,
+      GraphLense graphLense,
       RegisterAllocator registerAllocator,
       InternalOptions options) {
-    final DexBuilder builder = new DexBuilder(ir, registerAllocator, options);
+    final DexBuilder builder = new DexBuilder(ir, graphLense, registerAllocator, options);
     code = builder.build(method.getArity());
   }
 
diff --git a/src/main/java/com/android/tools/r8/graph/DexValue.java b/src/main/java/com/android/tools/r8/graph/DexValue.java
index ed99d25..2310891 100644
--- a/src/main/java/com/android/tools/r8/graph/DexValue.java
+++ b/src/main/java/com/android/tools/r8/graph/DexValue.java
@@ -557,7 +557,7 @@
 
     @Override
     public int hashCode() {
-      return (int) value * 19;
+      return (int) (value * 19);
     }
 
     @Override
@@ -615,7 +615,7 @@
 
     @Override
     public int hashCode() {
-      return (int) value * 29;
+      return (int) (value * 29);
     }
 
     @Override
diff --git a/src/main/java/com/android/tools/r8/ir/conversion/CfSourceCode.java b/src/main/java/com/android/tools/r8/ir/conversion/CfSourceCode.java
index ca79b0f..309e1d0 100644
--- a/src/main/java/com/android/tools/r8/ir/conversion/CfSourceCode.java
+++ b/src/main/java/com/android/tools/r8/ir/conversion/CfSourceCode.java
@@ -367,6 +367,13 @@
     }
     setLocalVariableLists();
     readEndingLocals(builder);
+    if (currentBlockInfo != null && instruction.canThrow()) {
+      Snapshot exceptionTransfer =
+          state.getSnapshot().exceptionTransfer(builder.getFactory().throwableType);
+      for (int target : currentBlockInfo.exceptionalSuccessors) {
+        recordStateForTarget(target, exceptionTransfer);
+      }
+    }
     if (isControlFlow(instruction)) {
       ensureDebugValueLivenessControl(builder);
       instruction.buildIR(builder, state, this);
@@ -376,13 +383,6 @@
       }
       state.clear();
     } else {
-      if (currentBlockInfo != null && instruction.canThrow()) {
-        Snapshot exceptionTransfer =
-            state.getSnapshot().exceptionTransfer(builder.getFactory().throwableType);
-        for (int target : currentBlockInfo.exceptionalSuccessors) {
-          recordStateForTarget(target, exceptionTransfer);
-        }
-      }
       instruction.buildIR(builder, state, this);
       ensureDebugValueLiveness(builder);
       if (builder.getCFG().containsKey(currentInstructionIndex + 1)) {
diff --git a/src/main/java/com/android/tools/r8/ir/conversion/DexBuilder.java b/src/main/java/com/android/tools/r8/ir/conversion/DexBuilder.java
index 8201562..ee7df48 100644
--- a/src/main/java/com/android/tools/r8/ir/conversion/DexBuilder.java
+++ b/src/main/java/com/android/tools/r8/ir/conversion/DexBuilder.java
@@ -43,6 +43,7 @@
 import com.android.tools.r8.graph.DexItemFactory;
 import com.android.tools.r8.graph.DexString;
 import com.android.tools.r8.graph.DexType;
+import com.android.tools.r8.graph.GraphLense;
 import com.android.tools.r8.ir.code.Argument;
 import com.android.tools.r8.ir.code.BasicBlock;
 import com.android.tools.r8.ir.code.CatchHandlers;
@@ -81,6 +82,10 @@
   // The IR representation of the code to build.
   private final IRCode ir;
 
+  // Graph lense for building the exception handlers. Needed since program classes that inherit
+  // from Throwable may get merged into their subtypes during class merging.
+  private final GraphLense graphLense;
+
   // The register allocator providing register assignments for the code to build.
   private final RegisterAllocator registerAllocator;
 
@@ -116,11 +121,14 @@
 
   public DexBuilder(
       IRCode ir,
+      GraphLense graphLense,
       RegisterAllocator registerAllocator,
       InternalOptions options) {
     assert ir != null;
+    assert graphLense != null;
     assert registerAllocator != null;
     this.ir = ir;
+    this.graphLense = graphLense;
     this.registerAllocator = registerAllocator;
     this.options = options;
   }
@@ -706,7 +714,12 @@
           assert i == handlerGroup.getGuards().size() - 1;
           catchAllOffset = targetOffset;
         } else {
-          pairs.add(new TypeAddrPair(type, targetOffset));
+          // The type may have changed due to class merging.
+          // TODO(christofferqa): This assumes that the graph lense is context insensitive for the
+          // given type (which is always the case). Consider removing the context-argument from
+          // GraphLense.lookupType, since we do not currently have a use case for it.
+          DexType actualType = graphLense.lookupType(type, null);
+          pairs.add(new TypeAddrPair(actualType, targetOffset));
         }
       }
       TypeAddrPair[] pairsArray = pairs.toArray(new TypeAddrPair[pairs.size()]);
diff --git a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
index 81dc436..df4e69c 100644
--- a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
+++ b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
@@ -532,7 +532,7 @@
     assert code.isConsistentSSA();
     code.traceBlocks();
     RegisterAllocator registerAllocator = performRegisterAllocation(code, method);
-    method.setCode(code, registerAllocator, options);
+    method.setCode(code, graphLense, registerAllocator, options);
     if (Log.ENABLED) {
       Log.debug(getClass(), "Resulting dex code for %s:\n%s",
           method.toSourceString(), logCode(options, method));
@@ -784,7 +784,7 @@
   private void finalizeToDex(DexEncodedMethod method, IRCode code, OptimizationFeedback feedback) {
     // Perform register allocation.
     RegisterAllocator registerAllocator = performRegisterAllocation(code, method);
-    method.setCode(code, registerAllocator, options);
+    method.setCode(code, graphLense, registerAllocator, options);
     updateHighestSortingStrings(method);
     if (Log.ENABLED) {
       Log.debug(getClass(), "Resulting dex code for %s:\n%s",
diff --git a/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java b/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java
index ed9cbdb..c4276dc 100644
--- a/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java
+++ b/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java
@@ -812,45 +812,45 @@
         skipWhitespace();
         switch (peekChar()) {
           case 'a':
-            if (found = acceptString("abstract")) {
+            if ((found = acceptString("abstract"))) {
               flags.setAbstract();
             }
             break;
           case 'f':
-            if (found = acceptString("final")) {
+            if ((found = acceptString("final"))) {
               flags.setFinal();
             }
             break;
           case 'n':
-            if (found = acceptString("native")) {
+            if ((found = acceptString("native"))) {
               flags.setNative();
             }
             break;
           case 'p':
-            if (found = acceptString("public")) {
+            if ((found = acceptString("public"))) {
               flags.setPublic();
-            } else if (found = acceptString("private")) {
+            } else if ((found = acceptString("private"))) {
               flags.setPrivate();
-            } else if (found = acceptString("protected")) {
+            } else if ((found = acceptString("protected"))) {
               flags.setProtected();
             }
             break;
           case 's':
-            if (found = acceptString("synchronized")) {
+            if ((found = acceptString("synchronized"))) {
               flags.setSynchronized();
-            } else if (found = acceptString("static")) {
+            } else if ((found = acceptString("static"))) {
               flags.setStatic();
-            } else if (found = acceptString("strictfp")) {
+            } else if ((found = acceptString("strictfp"))) {
               flags.setStrict();
             }
             break;
           case 't':
-            if (found = acceptString("transient")) {
+            if ((found = acceptString("transient"))) {
               flags.setTransient();
             }
             break;
           case 'v':
-            if (found = acceptString("volatile")) {
+            if ((found = acceptString("volatile"))) {
               flags.setVolatile();
             }
             break;
diff --git a/src/main/java/com/android/tools/r8/utils/LineNumberOptimizer.java b/src/main/java/com/android/tools/r8/utils/LineNumberOptimizer.java
index b938596..f10ff69 100644
--- a/src/main/java/com/android/tools/r8/utils/LineNumberOptimizer.java
+++ b/src/main/java/com/android/tools/r8/utils/LineNumberOptimizer.java
@@ -20,6 +20,7 @@
 import com.android.tools.r8.ir.code.Position;
 import com.android.tools.r8.naming.ClassNameMapper;
 import com.android.tools.r8.naming.ClassNaming;
+import com.android.tools.r8.naming.ClassNaming.Builder;
 import com.android.tools.r8.naming.MemberNaming;
 import com.android.tools.r8.naming.MemberNaming.FieldSignature;
 import com.android.tools.r8.naming.MemberNaming.MethodSignature;
@@ -187,6 +188,22 @@
     }
   }
 
+  // We will be remapping positional debug events and collect them as MappedPositions.
+  private static class MappedPosition {
+    private final DexMethod method;
+    private final int originalLine;
+    private final Position caller;
+    private final int obfuscatedLine;
+
+    private MappedPosition(
+        DexMethod method, int originalLine, Position caller, int obfuscatedLine) {
+      this.method = method;
+      this.originalLine = originalLine;
+      this.caller = caller;
+      this.obfuscatedLine = obfuscatedLine;
+    }
+  }
+
   public static ClassNameMapper run(
       DexApplication application, NamingLens namingLens, boolean identityMapping) {
     IdentityHashMap<DexString, List<DexProgramClass>> classesOfFiles = new IdentityHashMap<>();
@@ -199,25 +216,8 @@
         continue;
       }
 
-      // Group methods by name
       IdentityHashMap<DexString, List<DexEncodedMethod>> methodsByName =
-          new IdentityHashMap<>(clazz.directMethods().length + clazz.virtualMethods().length);
-      clazz.forEachMethod(
-          method -> {
-            // Add method only if renamed or contains positions.
-            if (namingLens.lookupName(method.method) != method.method.name
-                || doesContainPositions(method)) {
-              methodsByName.compute(
-                  method.method.name,
-                  (name, methods) -> {
-                    if (methods == null) {
-                      methods = new ArrayList<>();
-                    }
-                    methods.add(method);
-                    return methods;
-                  });
-            }
-          });
+          groupMethodsByName(namingLens, clazz);
 
       // At this point we don't know if we really need to add this class to the builder.
       // It depends on whether any methods/fields are renamed or some methods contain positions.
@@ -230,24 +230,11 @@
                       DescriptorUtils.descriptorToJavaType(renamedClassName.toString()),
                       clazz.toString()));
 
-      // We do know we need to create a ClassNaming.Builder if the class itself had been renamed.
-      if (!clazz.toString().equals(renamedClassName.toString())) {
-        // Not using return value, it's registered in classNameMapperBuilder
-        onDemandClassNamingBuilder.get();
-      }
+      // If the class is renamed add it to the classNamingBuilder.
+      addClassToClassNaming(clazz, renamedClassName, onDemandClassNamingBuilder);
 
       // First transfer renamed fields to classNamingBuilder.
-      clazz.forEachField(
-          dexEncodedField -> {
-            DexField dexField = dexEncodedField.field;
-            DexString renamedName = namingLens.lookupName(dexField);
-            if (renamedName != dexField.name) {
-              FieldSignature signature =
-                  new FieldSignature(dexField.name.toString(), dexField.type.toString());
-              MemberNaming memberNaming = new MemberNaming(signature, renamedName.toString());
-              onDemandClassNamingBuilder.get().addMemberEntry(memberNaming);
-            }
-          });
+      addFieldsToClassNaming(namingLens, clazz, onDemandClassNamingBuilder);
 
       // Then process the methods.
       for (List<DexEncodedMethod> methods : methodsByName.values()) {
@@ -256,47 +243,13 @@
           // deterministic behaviour: the algorithm will assign new line numbers in this order.
           // Methods with different names can share the same line numbers, that's why they don't
           // need to be sorted.
-          methods.sort(
-              (lhs, rhs) -> {
-                // Sort by startline, then DexEncodedMethod.slowCompare.
-                // Use startLine = 0 if no debuginfo.
-                Code lhsCode = lhs.getCode();
-                Code rhsCode = rhs.getCode();
-                DexCode lhsDexCode =
-                    lhsCode == null || !lhsCode.isDexCode() ? null : lhsCode.asDexCode();
-                DexCode rhsDexCode =
-                    rhsCode == null || !rhsCode.isDexCode() ? null : rhsCode.asDexCode();
-                DexDebugInfo lhsDebugInfo = lhsDexCode == null ? null : lhsDexCode.getDebugInfo();
-                DexDebugInfo rhsDebugInfo = rhsDexCode == null ? null : rhsDexCode.getDebugInfo();
-                int lhsStartLine = lhsDebugInfo == null ? 0 : lhsDebugInfo.startLine;
-                int rhsStartLine = rhsDebugInfo == null ? 0 : rhsDebugInfo.startLine;
-                int startLineDiff = lhsStartLine - rhsStartLine;
-                if (startLineDiff != 0) return startLineDiff;
-                return DexEncodedMethod.slowCompare(lhs, rhs);
-              });
+          sortMethods(methods);
         }
 
         PositionRemapper positionRemapper =
             identityMapping ? new IdentityPositionRemapper() : new OptimizingPositionRemapper();
 
         for (DexEncodedMethod method : methods) {
-
-          // We will be remapping positional debug events and collect them as MappedPositions.
-          class MappedPosition {
-            private final DexMethod method;
-            private final int originalLine;
-            private final Position caller;
-            private final int obfuscatedLine;
-
-            private MappedPosition(
-                DexMethod method, int originalLine, Position caller, int obfuscatedLine) {
-              this.method = method;
-              this.originalLine = originalLine;
-              this.caller = caller;
-              this.obfuscatedLine = obfuscatedLine;
-            }
-          }
-
           List<MappedPosition> mappedPositions = new ArrayList<>();
 
           if (doesContainPositions(method)) {
@@ -429,6 +382,75 @@
     return classNameMapperBuilder.build();
   }
 
+  // Sort by startline, then DexEncodedMethod.slowCompare.
+  // Use startLine = 0 if no debuginfo.
+  private static void sortMethods(List<DexEncodedMethod> methods) {
+    methods.sort(
+        (lhs, rhs) -> {
+          Code lhsCode = lhs.getCode();
+          Code rhsCode = rhs.getCode();
+          DexCode lhsDexCode =
+              lhsCode == null || !lhsCode.isDexCode() ? null : lhsCode.asDexCode();
+          DexCode rhsDexCode =
+              rhsCode == null || !rhsCode.isDexCode() ? null : rhsCode.asDexCode();
+          DexDebugInfo lhsDebugInfo = lhsDexCode == null ? null : lhsDexCode.getDebugInfo();
+          DexDebugInfo rhsDebugInfo = rhsDexCode == null ? null : rhsDexCode.getDebugInfo();
+          int lhsStartLine = lhsDebugInfo == null ? 0 : lhsDebugInfo.startLine;
+          int rhsStartLine = rhsDebugInfo == null ? 0 : rhsDebugInfo.startLine;
+          int startLineDiff = lhsStartLine - rhsStartLine;
+          if (startLineDiff != 0) return startLineDiff;
+          return DexEncodedMethod.slowCompare(lhs, rhs);
+        });
+  }
+
+  @SuppressWarnings("ReturnValueIgnored")
+  private static void addClassToClassNaming(DexProgramClass clazz, DexString renamedClassName,
+      Supplier<Builder> onDemandClassNamingBuilder) {
+    // We do know we need to create a ClassNaming.Builder if the class itself had been renamed.
+    if (!clazz.toString().equals(renamedClassName.toString())) {
+      // Not using return value, it's registered in classNameMapperBuilder
+      onDemandClassNamingBuilder.get();
+    }
+  }
+
+  private static void addFieldsToClassNaming(NamingLens namingLens, DexProgramClass clazz,
+      Supplier<Builder> onDemandClassNamingBuilder) {
+    clazz.forEachField(
+        dexEncodedField -> {
+          DexField dexField = dexEncodedField.field;
+          DexString renamedName = namingLens.lookupName(dexField);
+          if (renamedName != dexField.name) {
+            FieldSignature signature =
+                new FieldSignature(dexField.name.toString(), dexField.type.toString());
+            MemberNaming memberNaming = new MemberNaming(signature, renamedName.toString());
+            onDemandClassNamingBuilder.get().addMemberEntry(memberNaming);
+          }
+        });
+  }
+
+  private static IdentityHashMap<DexString, List<DexEncodedMethod>> groupMethodsByName(
+      NamingLens namingLens, DexProgramClass clazz) {
+    IdentityHashMap<DexString, List<DexEncodedMethod>> methodsByName =
+        new IdentityHashMap<>(clazz.directMethods().length + clazz.virtualMethods().length);
+    clazz.forEachMethod(
+        method -> {
+          // Add method only if renamed or contains positions.
+          if (namingLens.lookupName(method.method) != method.method.name
+              || doesContainPositions(method)) {
+            methodsByName.compute(
+                method.method.name,
+                (name, methods) -> {
+                  if (methods == null) {
+                    methods = new ArrayList<>();
+                  }
+                  methods.add(method);
+                  return methods;
+                });
+          }
+        });
+    return methodsByName;
+  }
+
   private static boolean doesContainPositions(DexEncodedMethod method) {
     Code code = method.getCode();
     if (code == null || !code.isDexCode()) {
diff --git a/src/test/examples/classmerging/ExceptionTest.java b/src/test/examples/classmerging/ExceptionTest.java
new file mode 100644
index 0000000..b365b2a
--- /dev/null
+++ b/src/test/examples/classmerging/ExceptionTest.java
@@ -0,0 +1,29 @@
+// Copyright (c) 2018, the R8 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.
+
+package classmerging;
+
+public class ExceptionTest {
+  public static void main(String[] args) {
+    // The following will lead to a catch handler for ExceptionA, which is merged into ExceptionB.
+    try {
+      throw new ExceptionB("Ouch!");
+    } catch (ExceptionA exception) {
+      System.out.println("Caught exception: " + exception.getMessage());
+    }
+  }
+
+  // Will be merged into ExceptionB when class merging is enabled.
+  public static class ExceptionA extends Exception {
+    public ExceptionA(String message) {
+      super(message);
+    }
+  }
+
+  public static class ExceptionB extends ExceptionA {
+    public ExceptionB(String message) {
+      super(message);
+    }
+  }
+}
diff --git a/src/test/examples/classmerging/keep-rules.txt b/src/test/examples/classmerging/keep-rules.txt
index 1cc5b87..f9e6d52 100644
--- a/src/test/examples/classmerging/keep-rules.txt
+++ b/src/test/examples/classmerging/keep-rules.txt
@@ -7,6 +7,9 @@
 -keep public class classmerging.Test {
   public static void main(...);
 }
+-keep public class classmerging.ExceptionTest {
+  public static void main(...);
+}
 
 # TODO(herhut): Consider supporting merging of inner-class attributes.
 # -keepattributes *
\ No newline at end of file
diff --git a/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java b/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java
index 4e07849..4f749b5 100644
--- a/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java
+++ b/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java
@@ -85,6 +85,11 @@
   }
 
   @Test
+  public void testInlining() throws Exception {
+    runTest("inlining.Inlining");
+  }
+
+  @Test
   public void testInstanceVariable() throws Exception {
     runTest("instancevariable.InstanceVariable");
   }
diff --git a/src/test/java/com/android/tools/r8/R8RunExamplesTest.java b/src/test/java/com/android/tools/r8/R8RunExamplesTest.java
index 348dbf1..087012c 100644
--- a/src/test/java/com/android/tools/r8/R8RunExamplesTest.java
+++ b/src/test/java/com/android/tools/r8/R8RunExamplesTest.java
@@ -41,6 +41,7 @@
         "filledarray.FilledArray",
         "hello.Hello",
         "ifstatements.IfStatements",
+        "inlining.Inlining",
         "instancevariable.InstanceVariable",
         "instanceofstring.InstanceofString",
         "invoke.Invoke",
diff --git a/src/test/java/com/android/tools/r8/TestBase.java b/src/test/java/com/android/tools/r8/TestBase.java
index fbf2d02..5200a09 100644
--- a/src/test/java/com/android/tools/r8/TestBase.java
+++ b/src/test/java/com/android/tools/r8/TestBase.java
@@ -151,6 +151,11 @@
     return builder.build();
   }
 
+  /** Build an AndroidApp from the specified program files. */
+  protected AndroidApp readProgramFiles(Path... programFiles) throws IOException {
+    return AndroidApp.builder().addProgramFiles(programFiles).build();
+  }
+
   /**
    * Create a temporary JAR file containing the specified test classes.
    */
diff --git a/src/test/java/com/android/tools/r8/classmerging/ClassMergingTest.java b/src/test/java/com/android/tools/r8/classmerging/ClassMergingTest.java
index d5d2c39..69f925c 100644
--- a/src/test/java/com/android/tools/r8/classmerging/ClassMergingTest.java
+++ b/src/test/java/com/android/tools/r8/classmerging/ClassMergingTest.java
@@ -3,29 +3,34 @@
 // BSD-style license that can be found in the LICENSE file.
 package com.android.tools.r8.classmerging;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import com.android.tools.r8.CompilationFailedException;
 import com.android.tools.r8.OutputMode;
 import com.android.tools.r8.R8Command;
+import com.android.tools.r8.TestBase;
 import com.android.tools.r8.ToolHelper;
-import com.android.tools.r8.shaking.ProguardRuleParserException;
+import com.android.tools.r8.utils.AndroidApp;
 import com.android.tools.r8.utils.DexInspector;
+import com.android.tools.r8.utils.DexInspector.FoundClassSubject;
 import com.android.tools.r8.utils.InternalOptions;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
 import java.io.IOException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.function.Consumer;
-import org.junit.Rule;
 import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
 
-public class ClassMergingTest {
+public class ClassMergingTest extends TestBase {
 
+  private static final Path CF_DIR =
+      Paths.get(ToolHelper.BUILD_DIR).resolve("classes/examples/classmerging");
   private static final Path EXAMPLE_JAR = Paths.get(ToolHelper.EXAMPLES_BUILD_DIR)
       .resolve("classmerging.jar");
   private static final Path EXAMPLE_KEEP = Paths.get(ToolHelper.EXAMPLES_DIR)
@@ -33,17 +38,14 @@
   private static final Path DONT_OPTIMIZE = Paths.get(ToolHelper.EXAMPLES_DIR)
       .resolve("classmerging").resolve("keep-rules-dontoptimize.txt");
 
-  @Rule
-  public TemporaryFolder temp = ToolHelper.getTemporaryFolderForTest();
-
   private void configure(InternalOptions options) {
     options.enableClassMerging = true;
     options.enableClassInlining = false;
+    options.enableMinification = false;
   }
 
   private void runR8(Path proguardConfig, Consumer<InternalOptions> optionsConsumer)
-      throws IOException, ProguardRuleParserException, ExecutionException,
-      CompilationFailedException {
+      throws IOException, ExecutionException, CompilationFailedException {
     ToolHelper.runR8(
         R8Command.builder()
             .setOutput(Paths.get(temp.getRoot().getCanonicalPath()), OutputMode.DexIndexed)
@@ -73,13 +75,12 @@
       assertFalse(inspector.clazz(candidate).isPresent());
     }
     assertTrue(inspector.clazz("classmerging.GenericInterfaceImpl").isPresent());
-    assertTrue(inspector.clazz("classmerging.GenericInterfaceImpl").isPresent());
     assertTrue(inspector.clazz("classmerging.Outer$SubClass").isPresent());
     assertTrue(inspector.clazz("classmerging.SubClass").isPresent());
   }
 
   @Test
-  public void testClassesShouldNotMerged() throws Exception {
+  public void testClassesHaveNotBeenMerged() throws Exception {
     runR8(DONT_OPTIMIZE, null);
     for (String candidate : CAN_BE_MERGED) {
       assertTrue(inspector.clazz(candidate).isPresent());
@@ -100,4 +101,39 @@
     assertTrue(inspector.clazz("classmerging.SubClassThatReferencesSuperMethod").isPresent());
   }
 
+  // If an exception class A is merged into another exception class B, then all exception tables
+  // should be updated, and class A should be removed entirely.
+  @Test
+  public void testExceptionTables() throws Exception {
+    String main = "classmerging.ExceptionTest";
+    Path[] programFiles =
+        new Path[] {
+          CF_DIR.resolve("ExceptionTest.class"),
+          CF_DIR.resolve("ExceptionTest$ExceptionA.class"),
+          CF_DIR.resolve("ExceptionTest$ExceptionB.class")
+        };
+    Set<String> preservedClassNames =
+        ImmutableSet.of("classmerging.ExceptionTest", "classmerging.ExceptionTest$ExceptionB");
+    runTest(main, programFiles, preservedClassNames);
+  }
+
+  private void runTest(String main, Path[] programFiles, Set<String> preservedClassNames)
+      throws Exception {
+    AndroidApp input = readProgramFiles(programFiles);
+    AndroidApp output = compileWithR8(input, EXAMPLE_KEEP, this::configure);
+    DexInspector inspector = new DexInspector(output);
+    // Check that all classes in [preservedClassNames] are in fact preserved.
+    for (String className : preservedClassNames) {
+      assertTrue(
+          "Class " + className + " should be present", inspector.clazz(className).isPresent());
+    }
+    // Check that all other classes have been removed.
+    for (FoundClassSubject classSubject : inspector.allClasses()) {
+      String className = classSubject.getDexClass().toSourceString();
+      assertTrue(
+          "Class " + className + " should be absent", preservedClassNames.contains(className));
+    }
+    // Check that the R8-generated code produces the same result as D8-generated code.
+    assertEquals(runOnArt(compileWithD8(input), main), runOnArt(output, main));
+  }
 }
diff --git a/src/test/java/com/android/tools/r8/maindexlist/MainDexListTests.java b/src/test/java/com/android/tools/r8/maindexlist/MainDexListTests.java
index 4214a67..d6e3612 100644
--- a/src/test/java/com/android/tools/r8/maindexlist/MainDexListTests.java
+++ b/src/test/java/com/android/tools/r8/maindexlist/MainDexListTests.java
@@ -38,6 +38,7 @@
 import com.android.tools.r8.graph.DexType;
 import com.android.tools.r8.graph.DexTypeList;
 import com.android.tools.r8.graph.DirectMappedDexApplication;
+import com.android.tools.r8.graph.GraphLense;
 import com.android.tools.r8.graph.MethodAccessFlags;
 import com.android.tools.r8.graph.ParameterAnnotationsList;
 import com.android.tools.r8.ir.code.CatchHandlers;
@@ -652,7 +653,7 @@
                 code);
         IRCode ir = code.buildIR(method, null, options, Origin.unknown());
         RegisterAllocator allocator = new LinearScanRegisterAllocator(ir, options);
-        method.setCode(ir, allocator, options);
+        method.setCode(ir, GraphLense.getIdentityLense(), allocator, options);
         directMethods[i] = method;
       }
       builder.addProgramClass(
diff --git a/src/test/java/com/android/tools/r8/utils/DexInspector.java b/src/test/java/com/android/tools/r8/utils/DexInspector.java
index ace5c9b..38de25e 100644
--- a/src/test/java/com/android/tools/r8/utils/DexInspector.java
+++ b/src/test/java/com/android/tools/r8/utils/DexInspector.java
@@ -3,6 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.
 package com.android.tools.r8.utils;
 
+import static org.junit.Assert.assertTrue;
+
 import com.android.tools.r8.StringResource;
 import com.android.tools.r8.code.Const4;
 import com.android.tools.r8.code.ConstString;
@@ -53,6 +55,7 @@
 import com.android.tools.r8.code.Throw;
 import com.android.tools.r8.dex.ApplicationReader;
 import com.android.tools.r8.graph.DexAnnotation;
+import com.android.tools.r8.graph.DexAnnotationElement;
 import com.android.tools.r8.graph.DexApplication;
 import com.android.tools.r8.graph.DexClass;
 import com.android.tools.r8.graph.DexCode;
@@ -65,6 +68,8 @@
 import com.android.tools.r8.graph.DexProto;
 import com.android.tools.r8.graph.DexType;
 import com.android.tools.r8.graph.DexValue;
+import com.android.tools.r8.graph.DexValue.DexValueArray;
+import com.android.tools.r8.graph.DexValue.DexValueString;
 import com.android.tools.r8.graph.InnerClassAttribute;
 import com.android.tools.r8.naming.ClassNameMapper;
 import com.android.tools.r8.naming.ClassNamingForNameMapper;
@@ -72,6 +77,8 @@
 import com.android.tools.r8.naming.MemberNaming.FieldSignature;
 import com.android.tools.r8.naming.MemberNaming.MethodSignature;
 import com.android.tools.r8.naming.MemberNaming.Signature;
+import com.android.tools.r8.naming.signature.GenericSignatureAction;
+import com.android.tools.r8.naming.signature.GenericSignatureParser;
 import com.android.tools.r8.smali.SmaliBuilder;
 import com.google.common.collect.BiMap;
 import com.google.common.collect.ImmutableList;
@@ -367,6 +374,10 @@
     public abstract boolean isLocalClass();
 
     public abstract boolean isAnonymousClass();
+
+    public abstract String getOriginalSignatureAttribute();
+
+    public abstract String getFinalSignatureAttribute();
   }
 
   private class AbsentClassSubject extends ClassSubject {
@@ -448,6 +459,16 @@
     public boolean isAnonymousClass() {
       return false;
     }
+
+    @Override
+    public String getOriginalSignatureAttribute() {
+      return null;
+    }
+
+    @Override
+    public String getFinalSignatureAttribute() {
+      return null;
+    }
   }
 
   public class FoundClassSubject extends ClassSubject {
@@ -641,6 +662,98 @@
     }
 
     @Override
+    public String getOriginalSignatureAttribute() {
+      // Build the generic signature using the current mapping if any.
+      class GenericSignatureGenerater implements GenericSignatureAction<String> {
+
+        private StringBuilder signature;
+
+        public String getSignature() {
+          return signature.toString();
+        }
+
+        @Override
+        public void parsedSymbol(char symbol) {
+          signature.append(symbol);
+        }
+
+        @Override
+        public void parsedIdentifier(String identifier) {
+          signature.append(identifier);
+        }
+
+        @Override
+        public String parsedTypeName(String name) {
+          String type = name;
+          if (originalToObfuscatedMapping != null) {
+            String original = originalToObfuscatedMapping.inverse().get(name);
+            type = original != null ? original : name;
+          }
+          signature.append(type);
+          return type;
+        }
+
+        @Override
+        public String parsedInnerTypeName(String enclosingType, String name) {
+          if (originalToObfuscatedMapping != null) {
+            // The enclosingType has already been mapped if a mapping is present.
+            String minifiedEnclosing = originalToObfuscatedMapping.get(enclosingType);
+            String type = originalToObfuscatedMapping.inverse().get(minifiedEnclosing + "$" + name);
+            if (type != null) {
+              assert type.startsWith(enclosingType + "$");
+              name = type.substring(enclosingType.length() + 1);
+            }
+            signature.append(name);
+            return type;
+          } else {
+            String type = enclosingType + "$" + name;
+            signature.append(name);
+            return type;
+          }
+        }
+
+        @Override
+        public void start() {
+          signature = new StringBuilder();
+        }
+
+        @Override
+        public void stop() {
+          // nothing to do
+        }
+      }
+
+      String finalSignature = getFinalSignatureAttribute();
+      if (finalSignature == null || mapping == null) {
+        return finalSignature;
+      }
+
+      GenericSignatureGenerater rewriter = new GenericSignatureGenerater();
+      GenericSignatureParser<String> parser = new GenericSignatureParser<>(rewriter);
+      parser.parseClassSignature(finalSignature);
+      return rewriter.getSignature();
+    }
+
+    @Override
+    public String getFinalSignatureAttribute() {
+      DexAnnotation annotation = findAnnotation("dalvik.annotation.Signature");
+      if (annotation == null) {
+        return null;
+      }
+      assert annotation.annotation.elements.length == 1;
+      DexAnnotationElement element = annotation.annotation.elements[0];
+      assert element.value instanceof DexValueArray;
+      StringBuilder builder = new StringBuilder();
+      DexValueArray valueArray = (DexValueArray) element.value;
+      for (DexValue value : valueArray.getValues()) {
+        assertTrue(value instanceof DexValueString);
+        DexValueString s = (DexValueString) value;
+        builder.append(s.getValue());
+      }
+      return builder.toString();
+    }
+
+    @Override
     public String toString() {
       return dexClass.toSourceString();
     }
diff --git a/tools/build_r8lib.py b/tools/build_r8lib.py
index c855bc5..4b7473e 100755
--- a/tools/build_r8lib.py
+++ b/tools/build_r8lib.py
@@ -25,16 +25,21 @@
 ANDROID_JAR = 'third_party/android_jar/lib-v%s/android.jar' % API_LEVEL
 
 
-def build_r8lib():
+def build_r8lib(output_path=None, output_map=None, **kwargs):
+  if output_path is None:
+    output_path = R8LIB_JAR
+  if output_map is None:
+    output_map = R8LIB_MAP_FILE
   toolhelper.run(
       'r8',
       ('--release',
        '--classfile',
        '--lib', utils.RT_JAR,
        utils.R8_JAR,
-       '--output', R8LIB_JAR,
+       '--output', output_path,
        '--pg-conf', utils.R8LIB_KEEP_RULES,
-       '--pg-map-output', R8LIB_MAP_FILE))
+       '--pg-map-output', output_map),
+      **kwargs)
 
 
 def test_d8sample():
diff --git a/tools/r8lib_size_compare.py b/tools/r8lib_size_compare.py
new file mode 100755
index 0000000..4bb49eb
--- /dev/null
+++ b/tools/r8lib_size_compare.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python
+# Copyright (c) 2018, the R8 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.
+
+'''
+Build r8lib.jar with both R8 and ProGuard and print a size comparison.
+
+By default, inlining is disabled in both R8 and ProGuard to make
+method-by-method comparison much easier. Pass --inlining to enable inlining.
+
+By default, only shows methods where R8's DEX output is 5 or more instructions
+larger than ProGuard+D8's output. Pass --threshold 0 to display all methods.
+'''
+
+import argparse
+import build_r8lib
+import os
+import subprocess
+import toolhelper
+import utils
+
+
+parser = argparse.ArgumentParser(description=__doc__.strip(),
+                                 formatter_class=argparse.RawTextHelpFormatter)
+parser.add_argument('-t', '--tmpdir',
+                    help='Store auxiliary files in given directory')
+parser.add_argument('-i', '--inlining', action='store_true',
+                    help='Enable inlining')
+parser.add_argument('--threshold')
+
+R8_RELOCATIONS = [
+  ('com.google.common', 'com.android.tools.r8.com.google.common'),
+  ('com.google.gson', 'com.android.tools.r8.com.google.gson'),
+  ('com.google.thirdparty', 'com.android.tools.r8.com.google.thirdparty'),
+  ('joptsimple', 'com.android.tools.r8.joptsimple'),
+  ('org.apache.commons', 'com.android.tools.r8.org.apache.commons'),
+  ('org.objectweb.asm', 'com.android.tools.r8.org.objectweb.asm'),
+  ('it.unimi.dsi.fastutil', 'com.android.tools.r8.it.unimi.dsi.fastutil'),
+]
+
+
+def is_output_newer(input, output):
+  if not os.path.exists(output):
+    return False
+  return os.stat(input).st_mtime < os.stat(output).st_mtime
+
+
+def check_call(args, **kwargs):
+  utils.PrintCmd(args)
+  return subprocess.check_call(args, **kwargs)
+
+
+def main(tmpdir=None, inlining=True,
+         run_jarsizecompare=True, threshold=None):
+  if tmpdir is None:
+    with utils.TempDir() as tmpdir:
+      return main(tmpdir, inlining)
+
+  inline_suffix = '-inline' if inlining else '-noinline'
+
+  pg_config = utils.R8LIB_KEEP_RULES
+  r8lib_jar = os.path.join(utils.LIBS, 'r8lib%s.jar' % inline_suffix)
+  r8lib_map = os.path.join(utils.LIBS, 'r8lib%s-map.txt' % inline_suffix)
+  r8lib_args = None
+  if not inlining:
+    r8lib_args = ['-Dcom.android.tools.r8.disableinlining=1']
+    pg_config = os.path.join(tmpdir, 'keep-noinline.txt')
+    with open(pg_config, 'w') as new_config:
+      with open(utils.R8LIB_KEEP_RULES) as old_config:
+        new_config.write(old_config.read().rstrip('\n') +
+                         '\n-optimizations !method/inlining/*\n')
+
+  if not is_output_newer(utils.R8_JAR, r8lib_jar):
+    r8lib_memory = os.path.join(tmpdir, 'r8lib%s-memory.txt' % inline_suffix)
+    build_r8lib.build_r8lib(
+        output_path=r8lib_jar, output_map=r8lib_map,
+        extra_args=r8lib_args, track_memory_file=r8lib_memory)
+
+  pg_output = os.path.join(tmpdir, 'r8lib-pg%s.jar' % inline_suffix)
+  pg_memory = os.path.join(tmpdir, 'r8lib-pg%s-memory.txt' % inline_suffix)
+  pg_map = os.path.join(tmpdir, 'r8lib-pg%s-map.txt' % inline_suffix)
+  pg_args = ['tools/track_memory.sh', pg_memory,
+             'third_party/proguard/proguard6.0.2/bin/proguard.sh',
+             '@' + pg_config,
+             '-lib', utils.RT_JAR,
+             '-injar', utils.R8_JAR,
+             '-printmapping', pg_map,
+             '-outjar', pg_output]
+  for library_name, relocated_package in utils.R8_RELOCATIONS:
+    pg_args.extend(['-dontwarn', relocated_package + '.**',
+                    '-dontnote', relocated_package + '.**'])
+  check_call(pg_args)
+  if threshold is None:
+    threshold = 5
+  toolhelper.run('jarsizecompare',
+                 ['--threshold', str(threshold),
+                  '--lib', utils.RT_JAR,
+                  '--input', 'input', utils.R8_JAR,
+                  '--input', 'r8', r8lib_jar, r8lib_map,
+                  '--input', 'pg', pg_output, pg_map])
+
+
+if __name__ == '__main__':
+  main(**vars(parser.parse_args()))
diff --git a/tools/toolhelper.py b/tools/toolhelper.py
index a7f509c..82a2824 100644
--- a/tools/toolhelper.py
+++ b/tools/toolhelper.py
@@ -9,7 +9,7 @@
 import utils
 
 def run(tool, args, build=None, debug=True,
-        profile=False, track_memory_file=None):
+        profile=False, track_memory_file=None, extra_args=None):
   if build is None:
     build, args = extract_build_from_args(args)
   if build:
@@ -18,6 +18,8 @@
   if track_memory_file:
     cmd.extend(['tools/track_memory.sh', track_memory_file])
   cmd.append('java')
+  if extra_args:
+    cmd.extend(extra_args)
   if debug:
     cmd.append('-ea')
   if profile: