| // Copyright (c) 2016, 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.shaking; |
| |
| 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.graph.DexType; |
| import com.android.tools.r8.graph.KeyedDexItem; |
| import com.android.tools.r8.graph.PresortedComparable; |
| import com.android.tools.r8.logging.Log; |
| import com.android.tools.r8.shaking.Enqueuer.AppInfoWithLiveness; |
| import com.android.tools.r8.utils.InternalOptions; |
| import com.android.tools.r8.utils.StringDiagnostic; |
| import com.google.common.collect.Sets; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Set; |
| |
| public class TreePruner { |
| |
| private DexApplication application; |
| private final AppInfoWithLiveness appInfo; |
| private final InternalOptions options; |
| private final UsagePrinter usagePrinter; |
| private final Set<DexType> prunedTypes = Sets.newIdentityHashSet(); |
| |
| public TreePruner( |
| DexApplication application, AppInfoWithLiveness appInfo, InternalOptions options) { |
| this.application = application; |
| this.appInfo = appInfo; |
| this.options = options; |
| this.usagePrinter = options.proguardConfiguration.isPrintUsage() |
| ? new UsagePrinter() : UsagePrinter.DONT_PRINT; |
| } |
| |
| public DexApplication run() { |
| application.timing.begin("Pruning application..."); |
| if (options.debugKeepRules && !options.skipMinification) { |
| |
| options.diagnosticsHandler.info( |
| new StringDiagnostic( |
| "Debugging keep rules on a minified build might yield broken builds, as " |
| + "minification also depends on the used keep rules. We recommend using " |
| + "--skip-minification.")); |
| } |
| DexApplication result; |
| try { |
| result = removeUnused(application).appendDeadCode(usagePrinter.toByteArray()).build(); |
| } finally { |
| application.timing.end(); |
| } |
| return result; |
| } |
| |
| private DexApplication.Builder<?> removeUnused(DexApplication application) { |
| return application.builder() |
| .replaceProgramClasses(getNewProgramClasses(application.classes())); |
| } |
| |
| private List<DexProgramClass> getNewProgramClasses(List<DexProgramClass> classes) { |
| List<DexProgramClass> newClasses = new ArrayList<>(); |
| for (DexProgramClass clazz : classes) { |
| if (!appInfo.liveTypes.contains(clazz.type)) { |
| // The class is completely unused and we can remove it. |
| if (Log.ENABLED) { |
| Log.debug(getClass(), "Removing class: " + clazz); |
| } |
| prunedTypes.add(clazz.type); |
| usagePrinter.printUnusedClass(clazz); |
| } else { |
| newClasses.add(clazz); |
| if (!appInfo.instantiatedTypes.contains(clazz.type) && |
| (!options.debugKeepRules || !clazz.hasDefaultInitializer())) { |
| // The class is only needed as a type but never instantiated. Make it abstract to reflect |
| // this. |
| if (clazz.accessFlags.isFinal()) { |
| // We cannot mark this class abstract, as it is final (not supported on Android). |
| // However, this might extend an abstract class and we might have removed the |
| // corresponding methods in this class. This might happen if we only keep this |
| // class around for its constants. |
| // For now, we remove the final flag to still be able to mark it abstract. |
| clazz.accessFlags.unsetFinal(); |
| } |
| clazz.accessFlags.setAbstract(); |
| } |
| // The class is used and must be kept. Remove the unused fields and methods from |
| // the class. |
| usagePrinter.visiting(clazz); |
| clazz.setDirectMethods(reachableMethods(clazz.directMethods(), clazz)); |
| clazz.setVirtualMethods(reachableMethods(clazz.virtualMethods(), clazz)); |
| clazz.setInstanceFields(reachableFields(clazz.instanceFields())); |
| clazz.setStaticFields(reachableFields(clazz.staticFields())); |
| usagePrinter.visited(); |
| } |
| } |
| return newClasses; |
| } |
| |
| private <S extends PresortedComparable<S>, T extends KeyedDexItem<S>> int firstUnreachableIndex( |
| T[] items, Set<S> live) { |
| for (int i = 0; i < items.length; i++) { |
| if (!live.contains(items[i].getKey())) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| private boolean isDefaultConstructor(DexEncodedMethod method) { |
| return method.isInstanceInitializer() |
| && method.method.proto.parameters.isEmpty(); |
| } |
| |
| private DexEncodedMethod[] reachableMethods(DexEncodedMethod[] methods, DexClass clazz) { |
| int firstUnreachable = firstUnreachableIndex(methods, appInfo.liveMethods); |
| // Return the original array if all methods are used. |
| if (firstUnreachable == -1) { |
| return methods; |
| } |
| ArrayList<DexEncodedMethod> reachableMethods = new ArrayList<>(methods.length); |
| for (int i = 0; i < firstUnreachable; i++) { |
| reachableMethods.add(methods[i]); |
| } |
| for (int i = firstUnreachable; i < methods.length; i++) { |
| DexEncodedMethod method = methods[i]; |
| if (appInfo.liveMethods.contains(methods[i].getKey())) { |
| reachableMethods.add(method); |
| } else if (options.debugKeepRules && isDefaultConstructor(method)) { |
| // Keep the method but rewrite its body, if it has one. |
| reachableMethods.add(methods[i].accessFlags.isAbstract() |
| ? method |
| : method.toMethodThatLogsError(application.dexItemFactory)); |
| } else if (appInfo.targetedMethods.contains(method.getKey())) { |
| if (Log.ENABLED) { |
| Log.debug(getClass(), "Making method %s abstract.", method.method); |
| } |
| // Final classes cannot be abstract, so we have to keep the method in that case. |
| // Also some other kinds of methods cannot be abstract, so keep them around. |
| boolean allowAbstract = clazz.accessFlags.isAbstract() |
| && !method.accessFlags.isFinal() |
| && !method.accessFlags.isNative() |
| && !method.accessFlags.isStrict() |
| && !method.accessFlags.isSynchronized(); |
| // By construction, private and static methods cannot be reachable but non-live. |
| assert !method.accessFlags.isPrivate() && !method.accessFlags.isStatic(); |
| reachableMethods.add(allowAbstract |
| ? method.toAbstractMethod() |
| : method.toEmptyThrowingMethod()); |
| } else { |
| if (Log.ENABLED) { |
| Log.debug(getClass(), "Removing method %s.", method.method); |
| } |
| usagePrinter.printUnusedMethod(method); |
| } |
| } |
| return reachableMethods.toArray(new DexEncodedMethod[reachableMethods.size()]); |
| } |
| |
| private DexEncodedField[] reachableFields(DexEncodedField[] fields) { |
| int firstUnreachable = firstUnreachableIndex(fields, appInfo.liveFields); |
| // Return the original array if all fields are used. |
| if (firstUnreachable == -1) { |
| return fields; |
| } |
| if (Log.ENABLED) { |
| Log.debug(getClass(), "Removing field: " + fields[firstUnreachable]); |
| } |
| usagePrinter.printUnusedField(fields[firstUnreachable]); |
| ArrayList<DexEncodedField> reachableFields = new ArrayList<>(fields.length); |
| for (int i = 0; i < firstUnreachable; i++) { |
| reachableFields.add(fields[i]); |
| } |
| for (int i = firstUnreachable + 1; i < fields.length; i++) { |
| DexEncodedField field = fields[i]; |
| if (appInfo.liveFields.contains(field.getKey())) { |
| reachableFields.add(field); |
| } else { |
| if (Log.ENABLED) { |
| Log.debug(getClass(), "Removing field: " + field); |
| } |
| usagePrinter.printUnusedField(field); |
| } |
| } |
| return reachableFields.toArray(new DexEncodedField[reachableFields.size()]); |
| } |
| |
| public Collection<DexType> getRemovedClasses() { |
| return Collections.unmodifiableCollection(prunedTypes); |
| } |
| } |
