| // Copyright (c) 2020, 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.ir.analysis.fieldvalueanalysis; |
| |
| import static com.android.tools.r8.ir.analysis.type.Nullability.maybeNull; |
| |
| import com.android.tools.r8.errors.Unreachable; |
| import com.android.tools.r8.graph.AppView; |
| 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.ir.analysis.type.ClassTypeLatticeElement; |
| import com.android.tools.r8.ir.analysis.type.TypeLatticeElement; |
| import com.android.tools.r8.ir.analysis.value.AbstractValue; |
| import com.android.tools.r8.ir.code.Argument; |
| import com.android.tools.r8.ir.code.BasicBlock; |
| import com.android.tools.r8.ir.code.FieldInstruction; |
| import com.android.tools.r8.ir.code.IRCode; |
| import com.android.tools.r8.ir.code.IRCodeUtils; |
| import com.android.tools.r8.ir.code.InstancePut; |
| import com.android.tools.r8.ir.code.Instruction; |
| import com.android.tools.r8.ir.code.InvokeDirect; |
| import com.android.tools.r8.ir.code.Value; |
| import com.android.tools.r8.ir.optimize.ClassInitializerDefaultsOptimization.ClassInitializerDefaultsResult; |
| import com.android.tools.r8.ir.optimize.info.OptimizationFeedback; |
| import com.android.tools.r8.ir.optimize.info.field.EmptyInstanceFieldInitializationInfoCollection; |
| import com.android.tools.r8.ir.optimize.info.field.InstanceFieldInitializationInfoCollection; |
| import com.android.tools.r8.ir.optimize.info.field.InstanceFieldInitializationInfoFactory; |
| import com.android.tools.r8.shaking.AppInfoWithLiveness; |
| |
| public class InstanceFieldValueAnalysis extends FieldValueAnalysis { |
| |
| // Information about how this instance constructor initializes the fields on the newly created |
| // instance. |
| private final InstanceFieldInitializationInfoCollection.Builder builder = |
| InstanceFieldInitializationInfoCollection.builder(); |
| |
| private final InstanceFieldInitializationInfoFactory factory; |
| |
| private final DexEncodedMethod parentConstructor; |
| private final InvokeDirect parentConstructorCall; |
| |
| private InstanceFieldValueAnalysis( |
| AppView<AppInfoWithLiveness> appView, |
| IRCode code, |
| OptimizationFeedback feedback, |
| DexProgramClass clazz, |
| DexEncodedMethod method, |
| DexEncodedMethod parentConstructor, |
| InvokeDirect parentConstructorCall) { |
| super(appView, code, feedback, clazz, method); |
| this.factory = appView.instanceFieldInitializationInfoFactory(); |
| this.parentConstructor = parentConstructor; |
| this.parentConstructorCall = parentConstructorCall; |
| } |
| |
| /** |
| * Returns information about how this instance constructor initializes the fields on the newly |
| * created instance. |
| */ |
| public static InstanceFieldInitializationInfoCollection run( |
| AppView<?> appView, |
| IRCode code, |
| ClassInitializerDefaultsResult classInitializerDefaultsResult, |
| OptimizationFeedback feedback, |
| DexEncodedMethod method) { |
| assert appView.appInfo().hasLiveness(); |
| assert appView.enableWholeProgramOptimizations(); |
| assert method.isInstanceInitializer(); |
| |
| DexProgramClass clazz = appView.definitionFor(method.method.holder).asProgramClass(); |
| if (!appView.options().enableValuePropagationForInstanceFields) { |
| return EmptyInstanceFieldInitializationInfoCollection.getInstance(); |
| } |
| |
| InvokeDirect parentConstructorCall = |
| IRCodeUtils.getUniqueConstructorInvoke(code.getThis(), appView.dexItemFactory()); |
| if (parentConstructorCall == null) { |
| return EmptyInstanceFieldInitializationInfoCollection.getInstance(); |
| } |
| |
| DexEncodedMethod parentConstructor = |
| parentConstructorCall.lookupSingleTarget(appView, clazz.type); |
| if (parentConstructor == null) { |
| return EmptyInstanceFieldInitializationInfoCollection.getInstance(); |
| } |
| |
| InstanceFieldValueAnalysis analysis = |
| new InstanceFieldValueAnalysis( |
| appView.withLiveness(), |
| code, |
| feedback, |
| clazz, |
| method, |
| parentConstructor, |
| parentConstructorCall); |
| analysis.computeFieldOptimizationInfo(classInitializerDefaultsResult); |
| analysis.analyzeParentConstructorCall(); |
| return analysis.builder.build(); |
| } |
| |
| @Override |
| boolean isSubjectToOptimization(DexEncodedField field) { |
| return !field.isStatic() && field.holder() == clazz.type; |
| } |
| |
| @Override |
| void updateFieldOptimizationInfo(DexEncodedField field, FieldInstruction fieldPut, Value value) { |
| if (fieldNeverWrittenBetweenInstancePutAndMethodExit(field, fieldPut.asInstancePut())) { |
| recordFieldIsInitializedWithValue(field, value); |
| } |
| } |
| |
| private void analyzeParentConstructorCall() { |
| InstanceFieldInitializationInfoCollection infos = |
| parentConstructor |
| .getOptimizationInfo() |
| .getInstanceInitializerInfo() |
| .fieldInitializationInfos(); |
| infos.forEach( |
| appView, |
| (field, info) -> { |
| if (fieldNeverWrittenBetweenParentConstructorCallAndMethodExit(field)) { |
| if (info.isArgumentInitializationInfo()) { |
| int argumentIndex = info.asArgumentInitializationInfo().getArgumentIndex(); |
| recordFieldIsInitializedWithValue( |
| field, parentConstructorCall.arguments().get(argumentIndex)); |
| } else { |
| assert info.isSingleValue() || info.isTypeInitializationInfo(); |
| builder.recordInitializationInfo(field, info); |
| } |
| } |
| }); |
| } |
| |
| private void recordFieldIsInitializedWithValue(DexEncodedField field, Value value) { |
| Value root = value.getAliasedValue(); |
| if (root.isDefinedByInstructionSatisfying(Instruction::isArgument)) { |
| Argument argument = root.definition.asArgument(); |
| builder.recordInitializationInfo( |
| field, factory.createArgumentInitializationInfo(argument.getIndex())); |
| return; |
| } |
| |
| AbstractValue abstractValue = value.getAbstractValue(appView, clazz.type); |
| if (abstractValue.isSingleValue()) { |
| builder.recordInitializationInfo(field, abstractValue.asSingleValue()); |
| return; |
| } |
| |
| DexType fieldType = field.field.type; |
| if (fieldType.isClassType()) { |
| ClassTypeLatticeElement dynamicLowerBoundType = value.getDynamicLowerBoundType(appView); |
| TypeLatticeElement dynamicUpperBoundType = value.getDynamicUpperBoundType(appView); |
| TypeLatticeElement staticFieldType = |
| TypeLatticeElement.fromDexType(fieldType, maybeNull(), appView); |
| if (dynamicLowerBoundType != null || !dynamicUpperBoundType.equals(staticFieldType)) { |
| builder.recordInitializationInfo( |
| field, |
| factory.createTypeInitializationInfo(dynamicLowerBoundType, dynamicUpperBoundType)); |
| } |
| } |
| } |
| |
| private boolean fieldNeverWrittenBetweenInstancePutAndMethodExit( |
| DexEncodedField field, InstancePut instancePut) { |
| if (field.isFinal()) { |
| return true; |
| } |
| |
| if (appView.appInfo().isFieldOnlyWrittenInMethod(field, method)) { |
| return true; |
| } |
| |
| if (appView.appInfo().isInstanceFieldWrittenOnlyInInstanceInitializers(field)) { |
| if (parentConstructorCall.getInvokedMethod().holder != clazz.type) { |
| // The field is only written in instance initializers of the enclosing class, and the |
| // constructor call targets a constructor in the super class. |
| return true; |
| } |
| |
| // The parent constructor call in this initializer targets another initializer on the same |
| // class (constructor forwarding), which could potentially assign this field. Therefore, we |
| // need to check that the instance-put instruction comes after the parent constructor call. |
| BasicBlock instancePutBlock = instancePut.getBlock(); |
| BasicBlock parentConstructorCallBlock = parentConstructorCall.getBlock(); |
| |
| if (instancePutBlock != parentConstructorCallBlock) { |
| // Check that the parent constructor call dominates the instance-put instruction. |
| return getOrCreateDominatorTree().dominatedBy(instancePutBlock, parentConstructorCallBlock); |
| } |
| |
| // Check that the parent constructor call comes before the instance-put instruction in the |
| // block. |
| for (Instruction instruction : instancePutBlock.getInstructions()) { |
| if (instruction == instancePut) { |
| return false; |
| } |
| if (instruction == parentConstructorCall) { |
| return true; |
| } |
| } |
| throw new Unreachable(); |
| } |
| |
| // Otherwise, conservatively return false. |
| return false; |
| } |
| |
| private boolean fieldNeverWrittenBetweenParentConstructorCallAndMethodExit( |
| DexEncodedField field) { |
| if (field.isFinal()) { |
| return true; |
| } |
| if (appView.appInfo().isFieldOnlyWrittenInMethod(field, parentConstructor)) { |
| return true; |
| } |
| // Otherwise, conservatively return false. |
| return false; |
| } |
| } |