| // 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.ir.optimize; |
| |
| import static com.android.tools.r8.graph.DexProgramClass.asProgramClassOrNull; |
| |
| import com.android.tools.r8.graph.AppView; |
| import com.android.tools.r8.graph.DexDefinition; |
| import com.android.tools.r8.graph.DexEncodedField; |
| import com.android.tools.r8.graph.DexEncodedMethod; |
| import com.android.tools.r8.graph.DexField; |
| import com.android.tools.r8.graph.DexMethod; |
| import com.android.tools.r8.graph.DexProgramClass; |
| import com.android.tools.r8.graph.DexReference; |
| import com.android.tools.r8.graph.DexType; |
| import com.android.tools.r8.ir.analysis.type.Nullability; |
| import com.android.tools.r8.ir.analysis.type.TypeAnalysis; |
| import com.android.tools.r8.ir.analysis.type.TypeElement; |
| import com.android.tools.r8.ir.analysis.value.AbstractValue; |
| import com.android.tools.r8.ir.analysis.value.SingleValue; |
| 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.IRMetadata; |
| import com.android.tools.r8.ir.code.InitClass; |
| import com.android.tools.r8.ir.code.InstancePut; |
| import com.android.tools.r8.ir.code.Instruction; |
| import com.android.tools.r8.ir.code.InstructionListIterator; |
| import com.android.tools.r8.ir.code.InvokeMethod; |
| import com.android.tools.r8.ir.code.InvokeStatic; |
| import com.android.tools.r8.ir.code.InvokeVirtual; |
| import com.android.tools.r8.ir.code.Position; |
| import com.android.tools.r8.ir.code.StaticGet; |
| import com.android.tools.r8.ir.code.StaticPut; |
| import com.android.tools.r8.ir.code.Value; |
| import com.android.tools.r8.ir.optimize.info.OptimizationFeedback; |
| import com.android.tools.r8.ir.optimize.info.OptimizationFeedbackSimple; |
| import com.android.tools.r8.shaking.AppInfoWithLiveness; |
| import com.android.tools.r8.shaking.ProguardMemberRule; |
| import com.android.tools.r8.shaking.ProguardMemberRuleReturnValue; |
| import com.android.tools.r8.utils.Reporter; |
| import com.android.tools.r8.utils.StringDiagnostic; |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.collect.Sets; |
| import java.util.ListIterator; |
| import java.util.Set; |
| |
| public class MemberValuePropagation { |
| |
| private static final OptimizationFeedback feedback = OptimizationFeedbackSimple.getInstance(); |
| |
| private final AppView<AppInfoWithLiveness> appView; |
| private final Reporter reporter; |
| |
| // Fields for which we have reported warnings to due Proguard configuration rules. |
| private final Set<DexField> warnedFields = Sets.newIdentityHashSet(); |
| |
| private enum RuleType { |
| NONE, |
| ASSUME_NO_SIDE_EFFECTS, |
| ASSUME_VALUES |
| } |
| |
| private static class ProguardMemberRuleLookup { |
| |
| final RuleType type; |
| final ProguardMemberRule rule; |
| |
| ProguardMemberRuleLookup(RuleType type, ProguardMemberRule rule) { |
| this.type = type; |
| this.rule = rule; |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (!(other instanceof ProguardMemberRuleLookup)) { |
| return false; |
| } |
| ProguardMemberRuleLookup otherLookup = (ProguardMemberRuleLookup) other; |
| return type == otherLookup.type && rule == otherLookup.rule; |
| } |
| |
| @Override |
| public int hashCode() { |
| return type.ordinal() * 31 + rule.hashCode(); |
| } |
| } |
| |
| public MemberValuePropagation(AppView<AppInfoWithLiveness> appView) { |
| this.appView = appView; |
| this.reporter = appView.options().reporter; |
| } |
| |
| private boolean mayPropagateValueFor(DexEncodedField field) { |
| if (field.isProgramField(appView)) { |
| return appView.appInfo().mayPropagateValueFor(field.field); |
| } |
| return appView.appInfo().assumedValues.containsKey(field.field) |
| || appView.appInfo().noSideEffects.containsKey(field.field); |
| } |
| |
| private boolean mayPropagateValueFor(DexEncodedMethod method) { |
| if (method.isProgramMethod(appView)) { |
| return appView.appInfo().mayPropagateValueFor(method.method); |
| } |
| return appView.appInfo().assumedValues.containsKey(method.method) |
| || appView.appInfo().noSideEffects.containsKey(method.method); |
| } |
| |
| private ProguardMemberRuleLookup lookupMemberRule(DexDefinition definition) { |
| if (definition == null) { |
| return null; |
| } |
| DexReference reference = definition.toReference(); |
| ProguardMemberRule rule = appView.appInfo().noSideEffects.get(reference); |
| if (rule != null) { |
| return new ProguardMemberRuleLookup(RuleType.ASSUME_NO_SIDE_EFFECTS, rule); |
| } |
| rule = appView.appInfo().assumedValues.get(reference); |
| if (rule != null) { |
| return new ProguardMemberRuleLookup(RuleType.ASSUME_VALUES, rule); |
| } |
| return null; |
| } |
| |
| private Instruction constantReplacementFromProguardRule( |
| ProguardMemberRule rule, IRCode code, Instruction instruction) { |
| if (rule == null || !rule.hasReturnValue()) { |
| return null; |
| } |
| |
| ProguardMemberRuleReturnValue returnValueRule = rule.getReturnValue(); |
| |
| // Check if this value can be assumed constant. |
| if (returnValueRule.isSingleValue()) { |
| return appView.abstractValueFactory() |
| .createSingleNumberValue(returnValueRule.getSingleValue()) |
| .createMaterializingInstruction(appView, code, instruction); |
| } |
| |
| TypeElement typeLattice = instruction.outValue().getType(); |
| if (returnValueRule.isField()) { |
| DexField field = returnValueRule.getField(); |
| assert typeLattice == TypeElement.fromDexType(field.type, Nullability.maybeNull(), appView); |
| |
| DexEncodedField staticField = appView.appInfo().lookupStaticTarget(field.holder, field); |
| if (staticField == null) { |
| if (warnedFields.add(field)) { |
| reporter.warning( |
| new StringDiagnostic( |
| "Field `" |
| + field.toSourceString() |
| + "` is used in an -assumevalues rule but does not exist.", |
| code.origin)); |
| } |
| return null; |
| } |
| |
| Instruction replacement = |
| staticField.valueAsConstInstruction(code, instruction.getLocalInfo(), appView); |
| if (replacement == null) { |
| reporter.warning( |
| new StringDiagnostic( |
| "Unable to apply the rule `" |
| + returnValueRule.toString() |
| + "`: Could not determine the value of field `" |
| + field.toSourceString() |
| + "`", |
| code.origin)); |
| return null; |
| } |
| return replacement; |
| } |
| |
| return null; |
| } |
| |
| private void setValueRangeFromProguardRule(ProguardMemberRule rule, Value value) { |
| if (rule.hasReturnValue() && rule.getReturnValue().isValueRange()) { |
| assert !rule.getReturnValue().isSingleValue(); |
| value.setValueRange(rule.getReturnValue().getValueRange()); |
| } |
| } |
| |
| private boolean tryConstantReplacementFromProguard( |
| IRCode code, |
| Set<Value> affectedValues, |
| ListIterator<BasicBlock> blocks, |
| InstructionListIterator iterator, |
| Instruction current, |
| ProguardMemberRuleLookup lookup) { |
| Instruction replacement = constantReplacementFromProguardRule(lookup.rule, code, current); |
| if (replacement == null) { |
| // Check to see if a value range can be assumed. |
| setValueRangeFromProguardRule(lookup.rule, current.outValue()); |
| return false; |
| } |
| affectedValues.addAll(current.outValue().affectedValues()); |
| if (lookup.type == RuleType.ASSUME_NO_SIDE_EFFECTS) { |
| iterator.replaceCurrentInstruction(replacement); |
| } else { |
| assert lookup.type == RuleType.ASSUME_VALUES; |
| BasicBlock block = current.getBlock(); |
| Position position = current.getPosition(); |
| if (current.hasOutValue()) { |
| assert replacement.outValue() != null; |
| current.outValue().replaceUsers(replacement.outValue()); |
| } |
| if (current.isStaticGet()) { |
| StaticGet staticGet = current.asStaticGet(); |
| replaceInstructionByInitClassIfPossible( |
| staticGet, staticGet.getField().holder, code, iterator, code.method.holder()); |
| } |
| replacement.setPosition(position); |
| if (block.hasCatchHandlers()) { |
| iterator.split(code, blocks).listIterator(code).add(replacement); |
| } else { |
| iterator.add(replacement); |
| } |
| } |
| return true; |
| } |
| |
| private void rewriteInvokeMethodWithConstantValues( |
| IRCode code, |
| DexType context, |
| Set<Value> affectedValues, |
| ListIterator<BasicBlock> blocks, |
| InstructionListIterator iterator, |
| InvokeMethod current) { |
| DexMethod invokedMethod = current.getInvokedMethod(); |
| DexType invokedHolder = invokedMethod.holder; |
| if (!invokedHolder.isClassType()) { |
| return; |
| } |
| DexEncodedMethod target = current.lookupSingleTarget(appView, context); |
| if (target != null && target.isInstanceInitializer()) { |
| // Member value propagation does not apply to constructors. Removing a call to a constructor |
| // that is marked as having no side effects could lead to verification errors, due to |
| // uninitialized instances being used. |
| return; |
| } |
| |
| ProguardMemberRuleLookup lookup = lookupMemberRule(target); |
| if (lookup == null) { |
| // -assumenosideeffects rules are applied to upward visible and overriding methods, but only |
| // references that have actual definitions are marked by the root set builder. So, here, we |
| // try again with a resolved target, not the direct definition, which may not exist. |
| DexEncodedMethod resolutionTarget = |
| appView.appInfo().resolveMethod(invokedHolder, invokedMethod).getSingleTarget(); |
| lookup = lookupMemberRule(resolutionTarget); |
| } |
| boolean invokeReplaced = false; |
| if (lookup != null) { |
| boolean hasUsedOutValue = current.hasOutValue() && current.outValue().isUsed(); |
| if (!hasUsedOutValue) { |
| if (lookup.type == RuleType.ASSUME_NO_SIDE_EFFECTS) { |
| // Remove invoke if marked as having no side effects and the return value is not used. |
| iterator.removeOrReplaceByDebugLocalRead(); |
| } |
| return; |
| } |
| |
| // Check to see if a constant value can be assumed. |
| // But, if the current matched rule is -assumenosideeffects without the return value, it won't |
| // be transformed into a replacement instruction. Check if there is -assumevalues rule bound |
| // to the target. |
| if (target != null |
| && lookup.type == RuleType.ASSUME_NO_SIDE_EFFECTS |
| && !lookup.rule.hasReturnValue()) { |
| ProguardMemberRule rule = appView.appInfo().assumedValues.get(target.toReference()); |
| if (rule != null) { |
| lookup = new ProguardMemberRuleLookup(RuleType.ASSUME_VALUES, rule); |
| } |
| } |
| invokeReplaced = |
| tryConstantReplacementFromProguard( |
| code, affectedValues, blocks, iterator, current, lookup); |
| } |
| if (invokeReplaced || !current.hasOutValue()) { |
| return; |
| } |
| // No Proguard rule could replace the instruction check for knowledge about the return value. |
| if (target == null || !mayPropagateValueFor(target)) { |
| return; |
| } |
| |
| AbstractValue abstractReturnValue = target.getOptimizationInfo().getAbstractReturnValue(); |
| if (abstractReturnValue.isSingleValue()) { |
| SingleValue singleReturnValue = abstractReturnValue.asSingleValue(); |
| if (singleReturnValue.isMaterializableInContext(appView, context)) { |
| BasicBlock block = current.getBlock(); |
| Position position = current.getPosition(); |
| |
| Instruction replacement = |
| singleReturnValue.createMaterializingInstruction(appView, code, current); |
| affectedValues.addAll(current.outValue().affectedValues()); |
| current.moveDebugValues(replacement); |
| current.outValue().replaceUsers(replacement.outValue()); |
| current.setOutValue(null); |
| |
| if (current.isInvokeMethodWithReceiver()) { |
| replaceInstructionByNullCheckIfPossible(current, iterator, context); |
| } else if (current.isInvokeStatic()) { |
| replaceInstructionByInitClassIfPossible( |
| current, target.holder(), code, iterator, context); |
| } |
| |
| // Insert the definition of the replacement. |
| replacement.setPosition(position); |
| if (block.hasCatchHandlers()) { |
| iterator.split(code, blocks).listIterator(code).add(replacement); |
| } else { |
| iterator.add(replacement); |
| } |
| target.getMutableOptimizationInfo().markAsPropagated(); |
| } |
| } |
| } |
| |
| private void rewriteFieldGetWithConstantValues( |
| IRCode code, |
| Set<Value> affectedValues, |
| ListIterator<BasicBlock> blocks, |
| InstructionListIterator iterator, |
| FieldInstruction current) { |
| DexField field = current.getField(); |
| |
| // TODO(b/123857022): Should be able to use definitionFor(). |
| DexEncodedField target = appView.appInfo().resolveField(field); |
| if (target == null) { |
| boolean replaceCurrentInstructionWithConstNull = |
| appView.withGeneratedExtensionRegistryShrinker( |
| shrinker -> shrinker.wasRemoved(field), false); |
| if (replaceCurrentInstructionWithConstNull) { |
| iterator.replaceCurrentInstruction(code.createConstNull()); |
| } |
| return; |
| } |
| |
| if (target.isStatic() != current.isStaticGet()) { |
| return; |
| } |
| |
| if (!mayPropagateValueFor(target)) { |
| return; |
| } |
| |
| // Check if there is a Proguard configuration rule that specifies the value of the field. |
| ProguardMemberRuleLookup lookup = lookupMemberRule(target); |
| if (lookup != null |
| && tryConstantReplacementFromProguard( |
| code, affectedValues, blocks, iterator, current, lookup)) { |
| return; |
| } |
| |
| // Check if the field is pinned. In that case, it could be written by reflection. |
| if (appView.appInfo().isPinned(target.field)) { |
| return; |
| } |
| |
| // Check if a this value is known const. |
| Instruction replacement = |
| target.valueAsConstInstruction(code, current.outValue().getLocalInfo(), appView); |
| if (replacement != null) { |
| BasicBlock block = current.getBlock(); |
| DexType context = code.method.holder(); |
| Position position = current.getPosition(); |
| |
| // All usages are replaced by the replacement value. |
| affectedValues.addAll(current.outValue().affectedValues()); |
| current.outValue().replaceUsers(replacement.outValue()); |
| |
| // To preserve side effects, original field-get is replaced by an explicit null-check, if |
| // the field-get instruction may only fail with an NPE, or the field-get remains as-is. |
| if (current.isInstanceGet()) { |
| replaceInstructionByNullCheckIfPossible(current, iterator, context); |
| } else { |
| replaceInstructionByInitClassIfPossible(current, target.holder(), code, iterator, context); |
| } |
| |
| // Insert the definition of the replacement. |
| replacement.setPosition(position); |
| if (block.hasCatchHandlers()) { |
| iterator.split(code, blocks).listIterator(code).add(replacement); |
| } else { |
| iterator.add(replacement); |
| } |
| feedback.markFieldAsPropagated(target); |
| } |
| } |
| |
| private void replaceInstructionByNullCheckIfPossible( |
| Instruction instruction, InstructionListIterator iterator, DexType context) { |
| assert instruction.isInstanceFieldInstruction() || instruction.isInvokeMethodWithReceiver(); |
| assert !instruction.hasOutValue() || !instruction.outValue().hasAnyUsers(); |
| if (instruction.instructionMayHaveSideEffects( |
| appView, context, Instruction.SideEffectAssumption.RECEIVER_NOT_NULL)) { |
| return; |
| } |
| Value receiver = |
| instruction.isInstanceFieldInstruction() |
| ? instruction.asInstanceFieldInstruction().object() |
| : instruction.asInvokeMethodWithReceiver().getReceiver(); |
| if (receiver.isNeverNull()) { |
| iterator.removeOrReplaceByDebugLocalRead(); |
| return; |
| } |
| InvokeMethod replacement; |
| if (appView.options().canUseRequireNonNull()) { |
| DexMethod requireNonNullMethod = appView.dexItemFactory().objectsMethods.requireNonNull; |
| replacement = new InvokeStatic(requireNonNullMethod, null, ImmutableList.of(receiver)); |
| } else { |
| DexMethod getClassMethod = appView.dexItemFactory().objectMembers.getClass; |
| replacement = new InvokeVirtual(getClassMethod, null, ImmutableList.of(receiver)); |
| } |
| iterator.replaceCurrentInstruction(replacement); |
| } |
| |
| private void replaceInstructionByInitClassIfPossible( |
| Instruction instruction, |
| DexType holder, |
| IRCode code, |
| InstructionListIterator iterator, |
| DexType context) { |
| assert instruction.isStaticFieldInstruction() || instruction.isInvokeStatic(); |
| if (instruction.instructionMayHaveSideEffects( |
| appView, context, Instruction.SideEffectAssumption.CLASS_ALREADY_INITIALIZED)) { |
| return; |
| } |
| boolean classInitializationMayHaveSideEffects = |
| holder.classInitializationMayHaveSideEffects( |
| appView, |
| // Types that are a super type of `context` are guaranteed to be initialized |
| // already. |
| type -> appView.isSubtype(context, type).isTrue(), |
| Sets.newIdentityHashSet()); |
| if (!classInitializationMayHaveSideEffects) { |
| iterator.removeOrReplaceByDebugLocalRead(); |
| return; |
| } |
| if (!appView.canUseInitClass()) { |
| return; |
| } |
| DexProgramClass clazz = asProgramClassOrNull(appView.definitionFor(holder)); |
| if (clazz != null) { |
| Value dest = code.createValue(TypeElement.getInt()); |
| iterator.replaceCurrentInstruction(new InitClass(dest, clazz.type)); |
| } |
| } |
| |
| private void replaceInstancePutByNullCheckIfNeverRead( |
| IRCode code, InstructionListIterator iterator, InstancePut current) { |
| DexEncodedField target = appView.appInfo().resolveField(current.getField()); |
| if (target == null || appView.appInfo().isFieldRead(target)) { |
| return; |
| } |
| |
| if (target.isStatic()) { |
| return; |
| } |
| |
| replaceInstructionByNullCheckIfPossible(current, iterator, code.method.holder()); |
| } |
| |
| private void replaceStaticPutByInitClassIfNeverRead( |
| IRCode code, InstructionListIterator iterator, StaticPut current) { |
| DexEncodedField field = appView.appInfo().resolveField(current.getField()); |
| if (field == null || appView.appInfo().isFieldRead(field)) { |
| return; |
| } |
| |
| if (!field.isStatic()) { |
| return; |
| } |
| |
| replaceInstructionByInitClassIfPossible( |
| current, field.holder(), code, iterator, code.method.holder()); |
| } |
| |
| /** |
| * Replace invoke targets and field accesses with constant values where possible. |
| * |
| * <p>Also assigns value ranges to values where possible. |
| */ |
| public void rewriteWithConstantValues(IRCode code, DexType callingContext) { |
| IRMetadata metadata = code.metadata(); |
| if (!metadata.mayHaveFieldInstruction() && !metadata.mayHaveInvokeMethod()) { |
| return; |
| } |
| |
| Set<Value> affectedValues = Sets.newIdentityHashSet(); |
| ListIterator<BasicBlock> blocks = code.listIterator(); |
| while (blocks.hasNext()) { |
| BasicBlock block = blocks.next(); |
| InstructionListIterator iterator = block.listIterator(code); |
| while (iterator.hasNext()) { |
| Instruction current = iterator.next(); |
| if (current.isInvokeMethod()) { |
| rewriteInvokeMethodWithConstantValues( |
| code, callingContext, affectedValues, blocks, iterator, current.asInvokeMethod()); |
| } else if (current.isFieldGet()) { |
| rewriteFieldGetWithConstantValues( |
| code, affectedValues, blocks, iterator, current.asFieldInstruction()); |
| } else if (current.isInstancePut()) { |
| replaceInstancePutByNullCheckIfNeverRead(code, iterator, current.asInstancePut()); |
| } else if (current.isStaticPut()) { |
| replaceStaticPutByInitClassIfNeverRead(code, iterator, current.asStaticPut()); |
| } |
| } |
| } |
| if (!affectedValues.isEmpty()) { |
| new TypeAnalysis(appView).narrowing(affectedValues); |
| } |
| assert code.isConsistentSSA(); |
| } |
| } |
