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// 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.horizontalclassmerging;
import static com.android.tools.r8.ir.conversion.ExtraUnusedParameter.computeExtraUnusedParameters;
import com.android.tools.r8.cf.CfVersion;
import com.android.tools.r8.classmerging.ClassMergerSharedData;
import com.android.tools.r8.dex.Constants;
import com.android.tools.r8.graph.AppInfoWithClassHierarchy;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.Code;
import com.android.tools.r8.graph.DexEncodedMethod;
import com.android.tools.r8.graph.DexItemFactory;
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.DexTypeUtils;
import com.android.tools.r8.graph.MethodAccessFlags;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.horizontalclassmerging.code.ConstructorEntryPointSynthesizedCode;
import com.android.tools.r8.ir.conversion.ExtraConstantIntParameter;
import com.android.tools.r8.ir.conversion.ExtraUnusedParameter;
import com.android.tools.r8.profile.rewriting.ProfileCollectionAdditions;
import com.android.tools.r8.utils.ArrayUtils;
import com.android.tools.r8.utils.BooleanUtils;
import com.android.tools.r8.utils.ListUtils;
import com.android.tools.r8.utils.SetUtils;
import com.android.tools.r8.utils.structural.Ordered;
import it.unimi.dsi.fastutil.ints.Int2ReferenceAVLTreeMap;
import it.unimi.dsi.fastutil.ints.Int2ReferenceSortedMap;
import it.unimi.dsi.fastutil.objects.Reference2IntMap;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
public class InstanceInitializerMerger {
private final AppView<? extends AppInfoWithClassHierarchy> appView;
private final Reference2IntMap<DexType> classIdentifiers;
private final DexItemFactory dexItemFactory;
private final HorizontalMergeGroup group;
private final List<ProgramMethod> instanceInitializers;
private final InstanceInitializerDescription instanceInitializerDescription;
private final HorizontalClassMergerGraphLens.Builder lensBuilder;
InstanceInitializerMerger(
AppView<? extends AppInfoWithClassHierarchy> appView,
Reference2IntMap<DexType> classIdentifiers,
HorizontalMergeGroup group,
List<ProgramMethod> instanceInitializers,
HorizontalClassMergerGraphLens.Builder lensBuilder) {
this(appView, classIdentifiers, group, instanceInitializers, lensBuilder, null);
}
InstanceInitializerMerger(
AppView<? extends AppInfoWithClassHierarchy> appView,
Reference2IntMap<DexType> classIdentifiers,
HorizontalMergeGroup group,
List<ProgramMethod> instanceInitializers,
HorizontalClassMergerGraphLens.Builder lensBuilder,
InstanceInitializerDescription instanceInitializerDescription) {
this.appView = appView;
this.classIdentifiers = classIdentifiers;
this.dexItemFactory = appView.dexItemFactory();
this.group = group;
this.instanceInitializers = instanceInitializers;
this.instanceInitializerDescription = instanceInitializerDescription;
this.lensBuilder = lensBuilder;
// Constructors should not be empty and all constructors should have the same prototype unless
// equivalent.
assert !instanceInitializers.isEmpty();
assert instanceInitializers.stream().map(ProgramMethod::getProto).distinct().count() == 1
|| instanceInitializerDescription != null;
}
public int getArity() {
return instanceInitializers.iterator().next().getReference().getArity();
}
public List<ProgramMethod> getInstanceInitializers() {
return instanceInitializers;
}
private CfVersion getNewClassFileVersion() {
CfVersion classFileVersion = null;
for (ProgramMethod instanceInitializer : instanceInitializers) {
if (instanceInitializer.getDefinition().hasClassFileVersion()) {
classFileVersion =
Ordered.maxIgnoreNull(
classFileVersion, instanceInitializer.getDefinition().getClassFileVersion());
}
}
return classFileVersion;
}
private DexMethod getNewMethodReference(ProgramMethod representative, boolean needsClassId) {
DexType[] oldParameters = representative.getParameters().values;
DexType[] newParameters =
new DexType[representative.getParameters().size() + BooleanUtils.intValue(needsClassId)];
System.arraycopy(oldParameters, 0, newParameters, 0, oldParameters.length);
for (int i = 0; i < oldParameters.length; i++) {
final int parameterIndex = i;
Set<DexType> parameterTypes =
SetUtils.newIdentityHashSet(
builder ->
instanceInitializers.forEach(
instanceInitializer ->
builder.accept(instanceInitializer.getParameter(parameterIndex))));
if (parameterTypes.size() > 1) {
newParameters[i] = DexTypeUtils.computeLeastUpperBound(appView, parameterTypes);
}
}
if (needsClassId) {
assert ArrayUtils.last(newParameters) == null;
newParameters[newParameters.length - 1] = dexItemFactory.intType;
}
return dexItemFactory.createInstanceInitializer(group.getTarget().getType(), newParameters);
}
/**
* Returns a special original method signature for the synthesized constructor that did not exist
* prior to horizontal class merging. Otherwise we might accidentally think that the synthesized
* constructor corresponds to the previous <init>() method on the target class, which could have
* unintended side-effects such as leading to unused argument removal being applied to the
* synthesized constructor all-though it by construction doesn't have any unused arguments.
*/
private DexMethod getSyntheticMethodReference(
ClassMethodsBuilder classMethodsBuilder, DexMethod newMethodReference) {
return dexItemFactory.createFreshMethodNameWithoutHolder(
Constants.SYNTHETIC_INSTANCE_INITIALIZER_PREFIX,
newMethodReference.getProto(),
newMethodReference.getHolderType(),
classMethodsBuilder::isFresh);
}
private Int2ReferenceSortedMap<DexMethod> createClassIdToInstanceInitializerMap() {
assert !hasInstanceInitializerDescription();
Int2ReferenceSortedMap<DexMethod> typeConstructorClassMap = new Int2ReferenceAVLTreeMap<>();
for (ProgramMethod instanceInitializer : instanceInitializers) {
typeConstructorClassMap.put(
classIdentifiers.getInt(instanceInitializer.getHolderType()),
instanceInitializer.getReference());
}
return typeConstructorClassMap;
}
public int size() {
return instanceInitializers.size();
}
public static class Builder {
private final AppView<? extends AppInfoWithClassHierarchy> appView;
private final Reference2IntMap<DexType> classIdentifiers;
private int estimatedDexCodeSize;
private final List<List<ProgramMethod>> instanceInitializerGroups = new ArrayList<>();
private final HorizontalClassMergerGraphLens.Builder lensBuilder;
public Builder(
AppView<? extends AppInfoWithClassHierarchy> appView,
Reference2IntMap<DexType> classIdentifiers,
HorizontalClassMergerGraphLens.Builder lensBuilder) {
this.appView = appView;
this.classIdentifiers = classIdentifiers;
this.lensBuilder = lensBuilder;
createNewGroup();
}
private void createNewGroup() {
estimatedDexCodeSize = 0;
instanceInitializerGroups.add(new ArrayList<>());
}
public Builder add(ProgramMethod instanceInitializer) {
int estimatedMaxSizeInBytes =
instanceInitializer.getDefinition().getCode().estimatedDexCodeSizeUpperBoundInBytes();
// If the constructor gets too large, then the constructor should be merged into a new group.
if (estimatedDexCodeSize + estimatedMaxSizeInBytes
> appView.options().minimumVerificationSizeLimitInBytes() / 2
&& estimatedDexCodeSize > 0) {
createNewGroup();
}
ListUtils.last(instanceInitializerGroups).add(instanceInitializer);
estimatedDexCodeSize += estimatedMaxSizeInBytes;
return this;
}
public Builder addEquivalent(ProgramMethod instanceInitializer) {
ListUtils.last(instanceInitializerGroups).add(instanceInitializer);
return this;
}
public List<InstanceInitializerMerger> build(HorizontalMergeGroup group) {
assert instanceInitializerGroups.stream().noneMatch(List::isEmpty);
return ListUtils.map(
instanceInitializerGroups,
instanceInitializers ->
new InstanceInitializerMerger(
appView, classIdentifiers, group, instanceInitializers, lensBuilder));
}
public InstanceInitializerMerger buildSingle(
HorizontalMergeGroup group, InstanceInitializerDescription instanceInitializerDescription) {
assert instanceInitializerGroups.stream().noneMatch(List::isEmpty);
assert instanceInitializerGroups.size() == 1;
List<ProgramMethod> instanceInitializers = ListUtils.first(instanceInitializerGroups);
return new InstanceInitializerMerger(
appView,
classIdentifiers,
group,
instanceInitializers,
lensBuilder,
instanceInitializerDescription);
}
}
private boolean hasInstanceInitializerDescription() {
return instanceInitializerDescription != null;
}
private DexMethod moveInstanceInitializer(
ClassMergerSharedData classMergerSharedData,
ClassMethodsBuilder classMethodsBuilder,
ProgramMethod instanceInitializer,
DexMethod reservedMethod) {
DexMethod newReference =
dexItemFactory.createInstanceInitializerWithFreshProto(
instanceInitializer.getReference().withHolder(group.getTarget(), dexItemFactory),
classMergerSharedData.getExtraUnusedArgumentTypes(),
candidate ->
classMethodsBuilder.isFresh(candidate)
&& candidate.isNotIdenticalTo(reservedMethod));
if (newReference.isIdenticalTo(instanceInitializer.getReference())) {
classMethodsBuilder.addDirectMethod(instanceInitializer.getDefinition());
return newReference;
}
DexEncodedMethod newMethod =
instanceInitializer
.getDefinition()
.toTypeSubstitutedMethodAsInlining(newReference, dexItemFactory);
classMethodsBuilder.addDirectMethod(newMethod);
return newReference;
}
private MethodAccessFlags getNewAccessFlags() {
return MethodAccessFlags.fromSharedAccessFlags(
Constants.ACC_PUBLIC | Constants.ACC_SYNTHETIC, true);
}
private Code getNewCode(boolean needsClassId, int numberOfUnusedArguments) {
if (hasInstanceInitializerDescription()) {
return instanceInitializerDescription.createCode(
group, needsClassId, numberOfUnusedArguments);
}
assert useSyntheticMethod();
return new ConstructorEntryPointSynthesizedCode(
createClassIdToInstanceInitializerMap(),
group.hasClassIdField() ? group.getClassIdField() : null,
numberOfUnusedArguments);
}
private boolean isSingleton() {
return instanceInitializers.size() == 1;
}
/** Synthesize a new method which selects the constructor based on a parameter type. */
@SuppressWarnings("ReferenceEquality")
void merge(
ClassMergerSharedData classMergerSharedData,
ProfileCollectionAdditions profileCollectionAdditions,
ClassMethodsBuilder classMethodsBuilder) {
ProgramMethod representative = ListUtils.first(instanceInitializers);
// Create merged instance initializer reference.
boolean needsClassId =
instanceInitializers.size() > 1
&& (!hasInstanceInitializerDescription() || group.hasClassIdField());
DexMethod newMethodReferenceTemplate = getNewMethodReference(representative, needsClassId);
DexMethod newMethodReference =
dexItemFactory.createInstanceInitializerWithFreshProto(
newMethodReferenceTemplate,
classMergerSharedData.getExtraUnusedArgumentTypes(),
classMethodsBuilder::isFresh);
// Compute the extra unused null parameters.
List<ExtraUnusedParameter> extraUnusedParameters =
computeExtraUnusedParameters(newMethodReferenceTemplate, newMethodReference);
// Move instance initializers to target class.
if (hasInstanceInitializerDescription()) {
lensBuilder.moveMethods(instanceInitializers, newMethodReference);
} else if (!useSyntheticMethod()) {
lensBuilder.moveMethod(representative.getReference(), newMethodReference, true);
} else {
for (ProgramMethod instanceInitializer : instanceInitializers) {
DexMethod movedInstanceInitializer =
moveInstanceInitializer(
classMergerSharedData,
classMethodsBuilder,
instanceInitializer,
newMethodReference);
lensBuilder.mapMethod(movedInstanceInitializer, movedInstanceInitializer);
lensBuilder.recordNewMethodSignature(
instanceInitializer.getReference(), movedInstanceInitializer);
// Amend the art profile collection.
profileCollectionAdditions.applyIfContextIsInProfile(
instanceInitializer.getReference(),
additionsBuilder -> additionsBuilder.addRule(representative));
}
}
// Add a mapping from a synthetic name to the synthetic constructor.
DexMethod syntheticMethodReference =
getSyntheticMethodReference(classMethodsBuilder, newMethodReference);
if (useSyntheticMethod()) {
lensBuilder.recordNewMethodSignature(syntheticMethodReference, newMethodReference, true);
}
// Map each of the instance initializers to the new instance initializer in the graph lens.
for (ProgramMethod instanceInitializer : instanceInitializers) {
ExtraConstantIntParameter extraParameter =
needsClassId
? new ExtraConstantIntParameter(
classIdentifiers.getInt(instanceInitializer.getHolderType()))
: null;
lensBuilder.mapMergedConstructor(
instanceInitializer.getReference(), newMethodReference, extraParameter);
}
DexEncodedMethod representativeMethod = representative.getDefinition();
DexEncodedMethod newInstanceInitializer;
if (!hasInstanceInitializerDescription() && !useSyntheticMethod()) {
newInstanceInitializer =
representativeMethod.toTypeSubstitutedMethodAsInlining(
newMethodReference, dexItemFactory);
} else {
newInstanceInitializer =
DexEncodedMethod.syntheticBuilder()
.setMethod(newMethodReference)
.setAccessFlags(getNewAccessFlags())
.setCode(getNewCode(needsClassId, extraUnusedParameters.size()))
.setClassFileVersion(getNewClassFileVersion())
.setApiLevelForDefinition(representativeMethod.getApiLevelForDefinition())
.setApiLevelForCode(representativeMethod.getApiLevelForCode())
.build();
}
classMethodsBuilder.addDirectMethod(newInstanceInitializer);
assert newInstanceInitializer.getCode().isDefaultInstanceInitializerCode()
|| newInstanceInitializer.getCode().isLirCode()
|| newInstanceInitializer.getCode().isIncompleteHorizontalClassMergerCode();
}
void setObsolete() {
if (hasInstanceInitializerDescription() || !useSyntheticMethod()) {
instanceInitializers.forEach(
instanceInitializer -> instanceInitializer.getDefinition().setObsolete());
}
}
private boolean useSyntheticMethod() {
return !isSingleton() || group.hasClassIdField();
}
}