| // 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.optimize; |
| |
| import com.android.tools.r8.graph.AppView; |
| import com.android.tools.r8.ir.code.Assume; |
| import com.android.tools.r8.ir.code.Assume.NoAssumption; |
| 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.Position; |
| import com.android.tools.r8.ir.code.Value; |
| import com.google.common.collect.Sets; |
| import java.util.ListIterator; |
| import java.util.Set; |
| import java.util.function.Predicate; |
| |
| public class AliasIntroducer implements Assumer { |
| private final AppView<?> appView; |
| |
| public AliasIntroducer(AppView<?> appView) { |
| this.appView = appView; |
| } |
| |
| @Override |
| public void insertAssumeInstructionsInBlocks( |
| IRCode code, ListIterator<BasicBlock> blockIterator, Predicate<BasicBlock> blockTester) { |
| while (blockIterator.hasNext()) { |
| BasicBlock block = blockIterator.next(); |
| if (blockTester.test(block)) { |
| insertAssumeNoneInstructionsInBlock(code, blockIterator, block); |
| } |
| } |
| } |
| |
| private void insertAssumeNoneInstructionsInBlock( |
| IRCode code, ListIterator<BasicBlock> blockIterator, BasicBlock block) { |
| Set<Assume<NoAssumption>> deferredInstructions = Sets.newIdentityHashSet(); |
| InstructionListIterator instructionIterator = block.listIterator(code); |
| while (instructionIterator.hasNext()) { |
| Instruction current = instructionIterator.next(); |
| if (!current.hasOutValue() || !current.outValue().isUsed()) { |
| continue; |
| } |
| Value outValue = current.outValue(); |
| // TODO(b/129859039): We may need similar concept when adding/testing assume-range |
| if (outValue.getTypeLattice().isPrimitive() |
| || outValue.getTypeLattice().isNullType()) { |
| continue; |
| } |
| // Split block if needed |
| BasicBlock insertionBlock = |
| block.hasCatchHandlers() ? instructionIterator.split(code, blockIterator) : block; |
| // Replace usages of out-value by the out-value of the AssumeNone instruction. |
| Value aliasedValue = code.createValue(outValue.getTypeLattice(), outValue.getLocalInfo()); |
| outValue.replaceUsers(aliasedValue); |
| // Insert AssumeNone instruction. |
| Assume<NoAssumption> assumeNone = |
| Assume.createAssumeNoneInstruction(aliasedValue, outValue, current, appView); |
| // {@link BasicBlock} needs Argument instructions to be packed. |
| if (current.isArgument()) { |
| deferredInstructions.add(assumeNone); |
| continue; |
| } |
| assumeNone.setPosition( |
| appView.options().debug ? current.getPosition() : Position.none()); |
| if (insertionBlock == block) { |
| instructionIterator.add(assumeNone); |
| } else { |
| insertionBlock.listIterator(code).add(assumeNone); |
| } |
| } |
| // For deferred instructions due to packed arguments, |
| // restart the iterator; move up to the last Argument instruction; and then add aliases. |
| if (!deferredInstructions.isEmpty()) { |
| final Position firstNonNonePosition = code.findFirstNonNonePosition(); |
| final InstructionListIterator it = block.listIterator(code); |
| it.nextUntil(i -> !i.isArgument()); |
| it.previous(); |
| deferredInstructions.forEach(i -> { |
| i.setPosition(firstNonNonePosition); |
| it.add(i); |
| }); |
| } |
| } |
| } |