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https://github.com/Eaglercraft-TeaVM-Fork/eagler-teavm.git
synced 2024-12-23 00:24:11 -08:00
Add nullness checker
This commit is contained in:
Alexey Andreev
Alexey Andreev
parent
0b4629d959
commit
2894c541f7
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@ -60,6 +60,11 @@ public class Program implements ProgramReader {
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return basicBlocks.get(index);
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}
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@Override
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public Iterable<BasicBlock> getBasicBlocks() {
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return basicBlocks;
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}
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public void deleteVariable(int index) {
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Variable variable = variables.get(index);
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if (variable == null) {
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@ -15,15 +15,13 @@
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*/
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package org.teavm.model;
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/**
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*
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* @author Alexey Andreev
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*/
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public interface ProgramReader {
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int basicBlockCount();
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BasicBlockReader basicBlockAt(int index);
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Iterable<? extends BasicBlockReader> getBasicBlocks();
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int variableCount();
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VariableReader variableAt(int index);
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289
core/src/main/java/org/teavm/model/analysis/NullnessChecker.java
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289
core/src/main/java/org/teavm/model/analysis/NullnessChecker.java
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@ -0,0 +1,289 @@
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/*
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* Copyright 2016 Alexey Andreev.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.teavm.model.analysis;
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import java.util.ArrayDeque;
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import java.util.HashSet;
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import java.util.List;
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import java.util.Queue;
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import java.util.Set;
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import org.teavm.common.DominatorTree;
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import org.teavm.common.Graph;
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import org.teavm.common.GraphBuilder;
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import org.teavm.common.GraphUtils;
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import org.teavm.model.BasicBlock;
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import org.teavm.model.BasicBlockReader;
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import org.teavm.model.FieldReference;
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import org.teavm.model.Incoming;
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import org.teavm.model.MethodReference;
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import org.teavm.model.Phi;
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import org.teavm.model.Program;
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import org.teavm.model.ValueType;
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import org.teavm.model.VariableReader;
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import org.teavm.model.instructions.AbstractInstructionReader;
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import org.teavm.model.instructions.ArrayElementType;
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import org.teavm.model.instructions.BinaryBranchingCondition;
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import org.teavm.model.instructions.BranchingCondition;
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import org.teavm.model.instructions.InvocationType;
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import org.teavm.model.util.ProgramUtils;
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public class NullnessChecker {
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Set<Incoming> notNullIncomings;
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List<List<Incoming>> phiOutputs;
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boolean[] notNull;
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boolean[] nullLiteral;
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GraphBuilder graphBuilder;
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public boolean[] check(Program program) {
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notNullIncomings = new HashSet<>();
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notNull = new boolean[program.variableCount()];
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nullLiteral = new boolean[program.variableCount()];
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phiOutputs = ProgramUtils.getPhiOutputs(program);
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graphBuilder = new GraphBuilder(program.variableCount());
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Graph cfg = ProgramUtils.buildControlFlowGraph(program);
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DominatorTree dom = GraphUtils.buildDominatorTree(cfg);
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Graph domGraph = GraphUtils.buildDominatorGraph(dom, cfg.size());
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Step[] stack = new Step[cfg.size() * 2];
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int head = 0;
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stack[head++] = new Step(0, notNull.clone());
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while (head > 0) {
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Step step = stack[--head];
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int node = step.node;
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BasicBlock block = program.basicBlockAt(node);
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InstructionReaderImpl reader = new InstructionReaderImpl(step.nonNull);
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block.readAllInstructions(reader);
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for (Phi phi : block.getPhis()) {
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for (Incoming incoming : phi.getIncomings()) {
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graphBuilder.addEdge(incoming.getValue().getIndex(), phi.getReceiver().getIndex());
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}
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}
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for (int successor : domGraph.outgoingEdges(node)) {
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boolean[] nextNonNull = step.nonNull.clone();
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if (successor == reader.notNullTarget && reader.notNullVariable >= 0) {
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nextNonNull[reader.notNullVariable] = true;
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}
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stack[head++] = new Step(successor, nextNonNull);
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}
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}
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propagateNullness(graphBuilder.build());
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boolean[] result = notNull;
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notNullIncomings = null;
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notNull = null;
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nullLiteral = null;
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phiOutputs = null;
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graphBuilder = null;
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return result;
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}
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private void propagateNullness(Graph graph) {
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Queue<Integer> worklist = new ArrayDeque<>();
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for (int i = 0; i < notNull.length; ++i) {
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if (notNull[i] && graph.outgoingEdgesCount(i) > 0) {
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for (int j : graph.outgoingEdges(i)) {
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if (!notNull[j]) {
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worklist.add(j);
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}
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}
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}
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}
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while (!worklist.isEmpty()) {
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int node = worklist.remove();
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if (notNull[node]) {
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continue;
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}
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notNull[node] = true;
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for (int next : graph.outgoingEdges(node)) {
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if (!notNull[next]) {
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worklist.add(next);
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}
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}
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}
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}
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class InstructionReaderImpl extends AbstractInstructionReader {
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boolean[] currentNotNull;
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int notNullTarget;
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int notNullVariable = -1;
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public InstructionReaderImpl(boolean[] currentNotNull) {
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this.currentNotNull = currentNotNull;
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}
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@Override
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public void nullConstant(VariableReader receiver) {
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nullLiteral[receiver.getIndex()] = true;
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}
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@Override
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public void classConstant(VariableReader receiver, ValueType cst) {
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notNull[receiver.getIndex()] = true;
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}
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@Override
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public void stringConstant(VariableReader receiver, String cst) {
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notNull[receiver.getIndex()] = true;
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}
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@Override
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public void assign(VariableReader receiver, VariableReader assignee) {
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if (currentNotNull[assignee.getIndex()]) {
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notNull[receiver.getIndex()] = true;
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}
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graphBuilder.addEdge(assignee.getIndex(), receiver.getIndex());
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}
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@Override
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public void invoke(VariableReader receiver, VariableReader instance, MethodReference method,
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List<? extends VariableReader> arguments, InvocationType type) {
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if (instance != null) {
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markAsCurrentNotNull(instance);
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}
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}
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@Override
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public void getField(VariableReader receiver, VariableReader instance, FieldReference field,
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ValueType fieldType) {
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if (instance != null) {
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markAsCurrentNotNull(instance);
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}
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}
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@Override
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public void putField(VariableReader instance, FieldReference field, VariableReader value, ValueType fieldType) {
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if (instance != null) {
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markAsCurrentNotNull(instance);
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}
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}
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@Override
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public void getElement(VariableReader receiver, VariableReader array, VariableReader index,
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ArrayElementType elementType) {
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markAsCurrentNotNull(array);
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}
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@Override
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public void putElement(VariableReader array, VariableReader index, VariableReader value,
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ArrayElementType elementType) {
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markAsCurrentNotNull(array);
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}
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@Override
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public void create(VariableReader receiver, String type) {
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notNull[receiver.getIndex()] = true;
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}
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@Override
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public void createArray(VariableReader receiver, ValueType itemType,
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List<? extends VariableReader> dimensions) {
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notNull[receiver.getIndex()] = true;
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}
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@Override
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public void createArray(VariableReader receiver, ValueType itemType, VariableReader size) {
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notNull[receiver.getIndex()] = true;
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}
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@Override
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public void arrayLength(VariableReader receiver, VariableReader array) {
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markAsCurrentNotNull(array);
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}
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@Override
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public void unwrapArray(VariableReader receiver, VariableReader array, ArrayElementType elementType) {
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notNull[receiver.getIndex()] = true;
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}
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@Override
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public void nullCheck(VariableReader receiver, VariableReader value) {
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notNull[receiver.getIndex()] = true;
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}
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@Override
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public void jumpIf(BranchingCondition cond, VariableReader operand, BasicBlockReader consequent,
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BasicBlockReader alternative) {
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switch (cond) {
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case NULL:
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notNullVariable = operand.getIndex();
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notNullTarget = alternative.getIndex();
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break;
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case NOT_NULL:
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notNullVariable = operand.getIndex();
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notNullTarget = consequent.getIndex();
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break;
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default:
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break;
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}
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}
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@Override
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public void jumpIf(BinaryBranchingCondition cond, VariableReader first, VariableReader second,
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BasicBlockReader consequent, BasicBlockReader alternative) {
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switch (cond) {
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case REFERENCE_EQUAL:
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if (nullLiteral[first.getIndex()]) {
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notNullVariable = second.getIndex();
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} else if (nullLiteral[second.getIndex()]) {
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notNullVariable = first.getIndex();
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}
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notNullTarget = alternative.getIndex();
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break;
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case REFERENCE_NOT_EQUAL:
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if (nullLiteral[first.getIndex()]) {
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notNullVariable = second.getIndex();
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} else if (nullLiteral[second.getIndex()]) {
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notNullVariable = first.getIndex();
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}
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notNullTarget = consequent.getIndex();
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break;
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default:
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break;
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}
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}
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private void markAsCurrentNotNull(VariableReader variable) {
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if (!currentNotNull[variable.getIndex()]) {
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currentNotNull[variable.getIndex()] = true;
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List<Incoming> outputs = phiOutputs.get(variable.getIndex());
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if (outputs != null) {
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for (Incoming output : outputs) {
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notNullIncomings.add(output);
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}
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}
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}
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}
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}
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static class Step {
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int node;
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boolean[] nonNull;
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public Step(int node, boolean[] nonNull) {
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this.node = node;
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this.nonNull = nonNull;
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}
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}
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}
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@ -15,10 +15,6 @@
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*/
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package org.teavm.model.instructions;
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/**
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*
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* @author Alexey Andreev
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*/
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public enum BinaryBranchingCondition {
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EQUAL,
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NOT_EQUAL,
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@ -15,10 +15,6 @@
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*/
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package org.teavm.model.instructions;
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/**
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*
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* @author Alexey Andreev
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*/
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public enum BranchingCondition {
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EQUAL,
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NOT_EQUAL,
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