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// Copyright (c) 2019, 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.desugar;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.CfCode;
import com.android.tools.r8.graph.DexApplication;
import com.android.tools.r8.graph.DexClass;
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.DexProto;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.ir.analysis.type.Nullability;
import com.android.tools.r8.ir.analysis.type.TypeLatticeElement;
import com.android.tools.r8.ir.code.BasicBlock;
import com.android.tools.r8.ir.code.IRCode;
import com.android.tools.r8.ir.code.Instruction;
import com.android.tools.r8.ir.code.InstructionListIterator;
import com.android.tools.r8.ir.code.Invoke;
import com.android.tools.r8.ir.code.InvokeMethod;
import com.android.tools.r8.ir.code.InvokeStatic;
import com.android.tools.r8.ir.code.Value;
import com.android.tools.r8.ir.conversion.IRConverter;
import com.android.tools.r8.ir.synthetic.DesugaredLibraryAPIConversionCfCodeProvider.APIConverterWrapperCfCodeProvider;
import com.android.tools.r8.utils.BooleanUtils;
import com.android.tools.r8.utils.DescriptorUtils;
import com.android.tools.r8.utils.StringDiagnostic;
import com.google.common.collect.Sets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
// TODO(b/134732760): In progress.
// I convert library calls with desugared parameters/return values so they can work normally.
// In the JSON of the desugared library, one can specify conversions between desugared and
// non-desugared types. If no conversion is specified, D8/R8 simply generate wrapper classes around
// the types. Wrappers induce both memory and runtime performance overhead. Wrappers overload
// all potential called APIs.
// Since many types are going to be rewritten, I also need to change the signature of the method
// called so that they are still called with the original types. Hence the vivified types.
// Given a type from the library, the prefix rewriter rewrites (->) as follow:
// vivifiedType -> type;
// type -> desugarType;
// No vivified types can be present in the compiled program (will necessarily be rewritten).
// DesugarType is only a rewritten type (generated through rewriting of type).
// The type, from the library, may either be rewritten to the desugarType,
// or be a rewritten type (generated through rewriting of vivifiedType).
public class DesugaredLibraryAPIConverter {
static final String VIVIFIED_PREFIX = "$-vivified-$.";
private final AppView<?> appView;
private final DexItemFactory factory;
private final DesugaredLibraryWrapperSynthesizer wrapperSynthesizor;
private final Map<DexClass, Set<DexEncodedMethod>> callBackMethods = new HashMap<>();
private final Set<DexMethod> trackedCallBackAPIs;
private final Set<DexMethod> trackedAPIs;
public DesugaredLibraryAPIConverter(AppView<?> appView) {
this.appView = appView;
this.factory = appView.dexItemFactory();
this.wrapperSynthesizor = new DesugaredLibraryWrapperSynthesizer(appView, this);
if (appView.options().testing.trackDesugaredAPIConversions) {
trackedCallBackAPIs = Sets.newConcurrentHashSet();
trackedAPIs = Sets.newConcurrentHashSet();
} else {
trackedCallBackAPIs = null;
trackedAPIs = null;
}
}
public static boolean isVivifiedType(DexType type) {
return type.descriptor.toString().startsWith("L" + VIVIFIED_PREFIX);
}
public void desugar(IRCode code) {
if (wrapperSynthesizor.hasSynthesized(code.method.method.holder)) {
return;
}
generateCallBackIfNeeded(code);
ListIterator<BasicBlock> blockIterator = code.listIterator();
while (blockIterator.hasNext()) {
BasicBlock block = blockIterator.next();
InstructionListIterator iterator = block.listIterator(code);
while (iterator.hasNext()) {
Instruction instruction = iterator.next();
if (!instruction.isInvokeMethod()) {
continue;
}
InvokeMethod invokeMethod = instruction.asInvokeMethod();
DexMethod invokedMethod = invokeMethod.getInvokedMethod();
// Rewriting is required only on calls to library methods which are not desugared.
if (appView.rewritePrefix.hasRewrittenType(invokedMethod.holder)
|| invokedMethod.holder.isArrayType()) {
continue;
}
DexClass dexClass = appView.definitionFor(invokedMethod.holder);
if (dexClass == null || !dexClass.isLibraryClass()) {
continue;
}
// Library methods do not understand desugared types, hence desugared types have to be
// converted around non desugared library calls for the invoke to resolve.
if (appView.rewritePrefix.hasRewrittenTypeInSignature(invokedMethod.proto)) {
rewriteLibraryInvoke(code, invokeMethod, iterator, blockIterator);
}
}
}
}
private void generateCallBackIfNeeded(IRCode code) {
// Any override of a library method can be called by the library.
// We duplicate the method to have a vivified type version callable by the library and
// a type version callable by the program. We need to add the vivified version to the rootset
// as it is actually overriding a library method (after changing the vivified type to the core
// library type), but the enqueuer cannot see that.
// To avoid too much computation we first look if the method would need to be rewritten if
// it would override a library method, then check if it overrides a library method.
if (code.method.isPrivateMethod() || code.method.isStatic()) {
return;
}
DexMethod method = code.method.method;
if (method.holder.isArrayType()
|| !appView.rewritePrefix.hasRewrittenTypeInSignature(method.proto)
|| appView
.options()
.desugaredLibraryConfiguration
.getEmulateLibraryInterface()
.containsKey(method.holder)) {
return;
}
DexClass dexClass = appView.definitionFor(method.holder);
if (dexClass == null) {
return;
}
if (overridesLibraryMethod(dexClass, method)) {
generateCallBack(dexClass, code.method);
}
}
private boolean overridesLibraryMethod(DexClass theClass, DexMethod method) {
// We look up everywhere to see if there is a supertype/interface implementing the method...
LinkedList<DexType> workList = new LinkedList<>();
Collections.addAll(workList, theClass.interfaces.values);
boolean foundOverrideToRewrite = false;
// There is no methods with desugared types on Object.
if (theClass.superType != factory.objectType) {
workList.add(theClass.superType);
}
while (!workList.isEmpty()) {
DexType current = workList.removeFirst();
DexClass dexClass = appView.definitionFor(current);
if (dexClass == null) {
continue;
}
workList.addAll(Arrays.asList(dexClass.interfaces.values));
if (dexClass.superType != factory.objectType) {
workList.add(dexClass.superType);
}
if (!dexClass.isLibraryClass() && !appView.options().isDesugaredLibraryCompilation()) {
continue;
}
DexEncodedMethod dexEncodedMethod = dexClass.lookupVirtualMethod(method);
if (dexEncodedMethod != null) {
// In this case, the object will be wrapped.
if (appView.rewritePrefix.hasRewrittenType(dexClass.type)) {
return false;
}
foundOverrideToRewrite = true;
}
}
return foundOverrideToRewrite;
}
private synchronized void generateCallBack(DexClass dexClass, DexEncodedMethod originalMethod) {
if (dexClass.isInterface()
&& originalMethod.isDefaultMethod()
&& (!appView.options().canUseDefaultAndStaticInterfaceMethods()
|| appView.options().isDesugaredLibraryCompilation())) {
// Interface method desugaring has been performed before and all the call-backs will be
// generated in all implementors of the interface. R8 cannot introduce new
// default methods at this point, but R8 does not need to do anything (the interface
// already implements the vivified version through inheritance, and all implementors
// support the call-back correctly).
return;
}
if (trackedCallBackAPIs != null) {
trackedCallBackAPIs.add(originalMethod.method);
}
addCallBackSignature(dexClass, originalMethod);
}
private synchronized void addCallBackSignature(DexClass dexClass, DexEncodedMethod method) {
assert dexClass.type == method.method.holder;
callBackMethods.putIfAbsent(dexClass, new HashSet<>());
callBackMethods.get(dexClass).add(method);
}
public static DexMethod methodWithVivifiedTypeInSignature(
DexMethod originalMethod, DexType holder, AppView<?> appView) {
DexType[] newParameters = originalMethod.proto.parameters.values.clone();
int index = 0;
for (DexType param : originalMethod.proto.parameters.values) {
if (appView.rewritePrefix.hasRewrittenType(param)) {
newParameters[index] = vivifiedTypeFor(param, appView);
}
index++;
}
DexType returnType = originalMethod.proto.returnType;
DexType newReturnType =
appView.rewritePrefix.hasRewrittenType(returnType)
? vivifiedTypeFor(returnType, appView)
: returnType;
DexProto newProto = appView.dexItemFactory().createProto(newReturnType, newParameters);
return appView.dexItemFactory().createMethod(holder, newProto, originalMethod.name);
}
public void generateWrappers(
DexApplication.Builder<?> builder, IRConverter irConverter, ExecutorService executorService)
throws ExecutionException {
if (appView.options().testing.trackDesugaredAPIConversions) {
generateTrackDesugaredAPIWarnings(trackedAPIs, "");
generateTrackDesugaredAPIWarnings(trackedCallBackAPIs, "callback ");
}
for (DexClass dexClass : callBackMethods.keySet()) {
Set<DexEncodedMethod> dexEncodedMethods =
generateCallbackMethods(callBackMethods.get(dexClass), dexClass);
dexClass.appendVirtualMethods(dexEncodedMethods);
irConverter.processMethodsConcurrently(dexEncodedMethods, executorService);
}
wrapperSynthesizor.finalizeWrappers(builder, irConverter, executorService);
}
private Set<DexEncodedMethod> generateCallbackMethods(
Set<DexEncodedMethod> originalMethods, DexClass dexClass) {
Set<DexEncodedMethod> newDexEncodedMethods = new HashSet<>();
for (DexEncodedMethod originalMethod : originalMethods) {
DexMethod methodToInstall =
methodWithVivifiedTypeInSignature(originalMethod.method, dexClass.type, appView);
CfCode cfCode =
new APIConverterWrapperCfCodeProvider(
appView, originalMethod.method, null, this, dexClass.isInterface())
.generateCfCode();
DexEncodedMethod newDexEncodedMethod =
wrapperSynthesizor.newSynthesizedMethod(methodToInstall, originalMethod, cfCode);
newDexEncodedMethod.setCode(cfCode, appView);
newDexEncodedMethods.add(newDexEncodedMethod);
}
return newDexEncodedMethods;
}
private void generateTrackDesugaredAPIWarnings(Set<DexMethod> tracked, String inner) {
StringBuilder sb = new StringBuilder();
sb.append("Tracked ").append(inner).append("desugared API conversions: ");
for (DexMethod method : tracked) {
sb.append("\n");
sb.append(method);
}
appView.options().reporter.warning(new StringDiagnostic(sb.toString()));
}
private void warnInvalidInvoke(DexType type, DexMethod invokedMethod, String debugString) {
DexType desugaredType = appView.rewritePrefix.rewrittenType(type);
appView
.options()
.reporter
.warning(
new StringDiagnostic(
"Invoke to "
+ invokedMethod.holder
+ "#"
+ invokedMethod.name
+ " may not work correctly at runtime ("
+ debugString
+ " type "
+ desugaredType
+ " is a desugared type)."));
}
public static DexType vivifiedTypeFor(DexType type, AppView<?> appView) {
DexType vivifiedType =
appView
.dexItemFactory()
.createType(DescriptorUtils.javaTypeToDescriptor(VIVIFIED_PREFIX + type.toString()));
appView.rewritePrefix.rewriteType(vivifiedType, type);
return vivifiedType;
}
private void rewriteLibraryInvoke(
IRCode code,
InvokeMethod invokeMethod,
InstructionListIterator iterator,
ListIterator<BasicBlock> blockIterator) {
DexMethod invokedMethod = invokeMethod.getInvokedMethod();
if (trackedAPIs != null) {
trackedAPIs.add(invokedMethod);
}
// Create return conversion if required.
Instruction returnConversion = null;
DexType newReturnType;
DexType returnType = invokedMethod.proto.returnType;
if (appView.rewritePrefix.hasRewrittenType(returnType)) {
if (canConvert(returnType)) {
newReturnType = vivifiedTypeFor(returnType, appView);
// Return conversion added only if return value is used.
if (invokeMethod.outValue() != null
&& invokeMethod.outValue().numberOfUsers() + invokeMethod.outValue().numberOfPhiUsers()
> 0) {
returnConversion =
createReturnConversionAndReplaceUses(code, invokeMethod, returnType, newReturnType);
}
} else {
warnInvalidInvoke(returnType, invokeMethod.getInvokedMethod(), "return");
newReturnType = returnType;
}
} else {
newReturnType = returnType;
}
// Create parameter conversions if required.
List<Instruction> parameterConversions = new ArrayList<>();
List<Value> newInValues = new ArrayList<>();
if (invokeMethod.isInvokeMethodWithReceiver()) {
assert !appView.rewritePrefix.hasRewrittenType(invokedMethod.holder);
newInValues.add(invokeMethod.asInvokeMethodWithReceiver().getReceiver());
}
int receiverShift = BooleanUtils.intValue(invokeMethod.isInvokeMethodWithReceiver());
DexType[] parameters = invokedMethod.proto.parameters.values;
DexType[] newParameters = parameters.clone();
for (int i = 0; i < parameters.length; i++) {
DexType argType = parameters[i];
if (appView.rewritePrefix.hasRewrittenType(argType)) {
if (canConvert(argType)) {
DexType argVivifiedType = vivifiedTypeFor(argType, appView);
Value inValue = invokeMethod.inValues().get(i + receiverShift);
newParameters[i] = argVivifiedType;
parameterConversions.add(
createParameterConversion(code, argType, argVivifiedType, inValue));
newInValues.add(parameterConversions.get(parameterConversions.size() - 1).outValue());
} else {
warnInvalidInvoke(argType, invokeMethod.getInvokedMethod(), "parameter");
newInValues.add(invokeMethod.inValues().get(i + receiverShift));
}
} else {
newInValues.add(invokeMethod.inValues().get(i + receiverShift));
}
}
// Patch the invoke with new types and new inValues.
DexProto newProto = factory.createProto(newReturnType, newParameters);
DexMethod newDexMethod =
factory.createMethod(invokedMethod.holder, newProto, invokedMethod.name);
Invoke newInvokeMethod =
Invoke.create(
invokeMethod.getType(),
newDexMethod,
newDexMethod.proto,
invokeMethod.outValue(),
newInValues);
assert newDexMethod
== methodWithVivifiedTypeInSignature(invokedMethod, invokedMethod.holder, appView);
// Insert and reschedule all instructions.
iterator.previous();
for (Instruction parameterConversion : parameterConversions) {
parameterConversion.setPosition(invokeMethod.getPosition());
iterator.add(parameterConversion);
}
assert iterator.peekNext() == invokeMethod;
iterator.next();
iterator.replaceCurrentInstruction(newInvokeMethod);
if (returnConversion != null) {
returnConversion.setPosition(invokeMethod.getPosition());
iterator.add(returnConversion);
}
// If the invoke is in a try-catch, since all conversions can throw, the basic block needs
// to be split in between each invoke...
if (newInvokeMethod.getBlock().hasCatchHandlers()) {
splitIfCatchHandlers(code, newInvokeMethod.getBlock(), blockIterator);
}
}
private void splitIfCatchHandlers(
IRCode code,
BasicBlock blockWithIncorrectThrowingInstructions,
ListIterator<BasicBlock> blockIterator) {
InstructionListIterator instructionsIterator =
blockWithIncorrectThrowingInstructions.listIterator(code);
BasicBlock currentBlock = blockWithIncorrectThrowingInstructions;
while (currentBlock != null && instructionsIterator.hasNext()) {
Instruction throwingInstruction =
instructionsIterator.nextUntil(Instruction::instructionTypeCanThrow);
BasicBlock nextBlock;
if (throwingInstruction != null) {
nextBlock = instructionsIterator.split(code, blockIterator);
// Back up to before the split before inserting catch handlers.
blockIterator.previous();
nextBlock.copyCatchHandlers(code, blockIterator, currentBlock, appView.options());
BasicBlock b = blockIterator.next();
assert b == nextBlock;
// Switch iteration to the split block.
instructionsIterator = nextBlock.listIterator(code);
currentBlock = nextBlock;
} else {
assert !instructionsIterator.hasNext();
instructionsIterator = null;
currentBlock = null;
}
}
}
private Instruction createParameterConversion(
IRCode code, DexType argType, DexType argVivifiedType, Value inValue) {
DexMethod conversionMethod = createConversionMethod(argType, argType, argVivifiedType);
// The value is null only if the input is null.
Value convertedValue =
createConversionValue(code, inValue.getTypeLattice().nullability(), argVivifiedType);
return new InvokeStatic(conversionMethod, convertedValue, Collections.singletonList(inValue));
}
private Instruction createReturnConversionAndReplaceUses(
IRCode code, InvokeMethod invokeMethod, DexType returnType, DexType returnVivifiedType) {
DexMethod conversionMethod = createConversionMethod(returnType, returnVivifiedType, returnType);
Value convertedValue = createConversionValue(code, Nullability.maybeNull(), returnType);
invokeMethod.outValue().replaceUsers(convertedValue);
return new InvokeStatic(
conversionMethod, convertedValue, Collections.singletonList(invokeMethod.outValue()));
}
public DexMethod createConversionMethod(DexType type, DexType srcType, DexType destType) {
// ConversionType holds the methods "rewrittenType convert(type)" and the other way around.
// But everything is going to be rewritten, so we need to use vivifiedType and type".
DexType conversionHolder =
appView.options().desugaredLibraryConfiguration.getCustomConversions().get(type);
if (conversionHolder == null) {
conversionHolder =
type == srcType
? wrapperSynthesizor.getTypeWrapper(type)
: wrapperSynthesizor.getVivifiedTypeWrapper(type);
}
assert conversionHolder != null;
return factory.createMethod(
conversionHolder, factory.createProto(destType, srcType), factory.convertMethodName);
}
private Value createConversionValue(IRCode code, Nullability nullability, DexType valueType) {
return code.createValue(TypeLatticeElement.fromDexType(valueType, nullability, appView));
}
public boolean canConvert(DexType type) {
return appView.options().desugaredLibraryConfiguration.getCustomConversions().containsKey(type)
|| wrapperSynthesizor.canGenerateWrapper(type);
}
}