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org.jetbrains.kotlin.cfg.PseudocodeVariablesData Maven / Gradle / Ivy
/*
* Copyright 2010-2015 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jetbrains.kotlin.cfg;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.kotlin.cfg.pseudocode.Pseudocode;
import org.jetbrains.kotlin.cfg.pseudocode.PseudocodeUtil;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.Instruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.LexicalScope;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.ReadValueInstruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.WriteValueInstruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.LocalFunctionDeclarationInstruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.VariableDeclarationInstruction;
import org.jetbrains.kotlin.cfg.pseudocodeTraverser.Edges;
import org.jetbrains.kotlin.descriptors.DeclarationDescriptor;
import org.jetbrains.kotlin.descriptors.VariableDescriptor;
import org.jetbrains.kotlin.psi.KtDeclaration;
import org.jetbrains.kotlin.psi.KtProperty;
import org.jetbrains.kotlin.resolve.BindingContext;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import static org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder.BACKWARD;
import static org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder.FORWARD;
public class PseudocodeVariablesData {
private final Pseudocode pseudocode;
private final BindingContext bindingContext;
private final PseudocodeVariableDataCollector pseudocodeVariableDataCollector;
private final Map> declaredVariablesForDeclaration = Maps.newHashMap();
private Map>> variableInitializers;
public PseudocodeVariablesData(@NotNull Pseudocode pseudocode, @NotNull BindingContext bindingContext) {
this.pseudocode = pseudocode;
this.bindingContext = bindingContext;
this.pseudocodeVariableDataCollector = new PseudocodeVariableDataCollector(bindingContext, pseudocode);
}
@NotNull
public Pseudocode getPseudocode() {
return pseudocode;
}
@NotNull
public LexicalScopeVariableInfo getLexicalScopeVariableInfo() {
return pseudocodeVariableDataCollector.getLexicalScopeVariableInfo();
}
@NotNull
public Set getDeclaredVariables(@NotNull Pseudocode pseudocode, boolean includeInsideLocalDeclarations) {
if (!includeInsideLocalDeclarations) {
return getUpperLevelDeclaredVariables(pseudocode);
}
Set declaredVariables = Sets.newHashSet();
declaredVariables.addAll(getUpperLevelDeclaredVariables(pseudocode));
for (LocalFunctionDeclarationInstruction localFunctionDeclarationInstruction : pseudocode.getLocalDeclarations()) {
Pseudocode localPseudocode = localFunctionDeclarationInstruction.getBody();
declaredVariables.addAll(getUpperLevelDeclaredVariables(localPseudocode));
}
return declaredVariables;
}
@NotNull
private Set getUpperLevelDeclaredVariables(@NotNull Pseudocode pseudocode) {
Set declaredVariables = declaredVariablesForDeclaration.get(pseudocode);
if (declaredVariables == null) {
declaredVariables = computeDeclaredVariablesForPseudocode(pseudocode);
declaredVariablesForDeclaration.put(pseudocode, declaredVariables);
}
return declaredVariables;
}
@NotNull
private Set computeDeclaredVariablesForPseudocode(Pseudocode pseudocode) {
Set declaredVariables = Sets.newHashSet();
for (Instruction instruction : pseudocode.getInstructions()) {
if (instruction instanceof VariableDeclarationInstruction) {
KtDeclaration variableDeclarationElement = ((VariableDeclarationInstruction) instruction).getVariableDeclarationElement();
DeclarationDescriptor descriptor = bindingContext.get(BindingContext.DECLARATION_TO_DESCRIPTOR, variableDeclarationElement);
if (descriptor != null) {
assert descriptor instanceof VariableDescriptor;
declaredVariables.add((VariableDescriptor) descriptor);
}
}
}
return Collections.unmodifiableSet(declaredVariables);
}
// variable initializers
@NotNull
public Map>> getVariableInitializers() {
if (variableInitializers == null) {
variableInitializers = computeVariableInitializers();
}
return variableInitializers;
}
@NotNull
private Map>> computeVariableInitializers() {
final LexicalScopeVariableInfo lexicalScopeVariableInfo = pseudocodeVariableDataCollector.getLexicalScopeVariableInfo();
return pseudocodeVariableDataCollector.collectData(
FORWARD, /*mergeDataWithLocalDeclarations=*/ false,
new InstructionDataMergeStrategy() {
@NotNull
@Override
public Edges> invoke(
@NotNull Instruction instruction,
@NotNull Collection> incomingEdgesData
) {
Map enterInstructionData =
mergeIncomingEdgesDataForInitializers(incomingEdgesData);
Map exitInstructionData = addVariableInitStateFromCurrentInstructionIfAny(
instruction, enterInstructionData, lexicalScopeVariableInfo);
return new Edges>(enterInstructionData, exitInstructionData);
}
}
);
}
public static VariableControlFlowState getDefaultValueForInitializers(
@NotNull VariableDescriptor variable,
@NotNull Instruction instruction,
@NotNull LexicalScopeVariableInfo lexicalScopeVariableInfo
) {
//todo: think of replacing it with "MapWithDefaultValue"
LexicalScope declaredIn = lexicalScopeVariableInfo.getDeclaredIn().get(variable);
boolean declaredOutsideThisDeclaration =
declaredIn == null //declared outside this pseudocode
|| declaredIn.getLexicalScopeForContainingDeclaration() != instruction.getLexicalScope().getLexicalScopeForContainingDeclaration();
return VariableControlFlowState.create(/*initState=*/declaredOutsideThisDeclaration);
}
@NotNull
private static Map mergeIncomingEdgesDataForInitializers(
@NotNull Collection> incomingEdgesData
) {
Set variablesInScope = Sets.newHashSet();
for (Map edgeData : incomingEdgesData) {
variablesInScope.addAll(edgeData.keySet());
}
Map enterInstructionData = Maps.newHashMap();
for (VariableDescriptor variable : variablesInScope) {
TriInitState initState = null;
boolean isDeclared = true;
for (Map edgeData : incomingEdgesData) {
VariableControlFlowState varControlFlowState = edgeData.get(variable);
if (varControlFlowState != null) {
initState = initState != null ? initState.merge(varControlFlowState.initState) : varControlFlowState.initState;
if (!varControlFlowState.isDeclared) {
isDeclared = false;
}
}
}
if (initState == null) {
throw new AssertionError("An empty set of incoming edges data");
}
enterInstructionData.put(variable, VariableControlFlowState.create(initState, isDeclared));
}
return enterInstructionData;
}
@NotNull
private Map addVariableInitStateFromCurrentInstructionIfAny(
@NotNull Instruction instruction,
@NotNull Map enterInstructionData,
@NotNull LexicalScopeVariableInfo lexicalScopeVariableInfo
) {
if (!(instruction instanceof WriteValueInstruction) && !(instruction instanceof VariableDeclarationInstruction)) {
return enterInstructionData;
}
VariableDescriptor variable = PseudocodeUtil.extractVariableDescriptorIfAny(instruction, false, bindingContext);
if (variable == null) {
return enterInstructionData;
}
Map exitInstructionData = Maps.newHashMap(enterInstructionData);
if (instruction instanceof WriteValueInstruction) {
// if writing to already initialized object
if (!PseudocodeUtil.isThisOrNoDispatchReceiver((WriteValueInstruction) instruction, bindingContext)) {
return enterInstructionData;
}
VariableControlFlowState enterInitState = enterInstructionData.get(variable);
VariableControlFlowState initializationAtThisElement =
VariableControlFlowState
.create(((WriteValueInstruction) instruction).getElement() instanceof KtProperty, enterInitState);
exitInstructionData.put(variable, initializationAtThisElement);
}
else { // instruction instanceof VariableDeclarationInstruction
VariableControlFlowState enterInitState = enterInstructionData.get(variable);
if (enterInitState == null) {
enterInitState = getDefaultValueForInitializers(variable, instruction, lexicalScopeVariableInfo);
}
if (enterInitState == null || !enterInitState.mayBeInitialized() || !enterInitState.isDeclared) {
boolean isInitialized = enterInitState != null && enterInitState.mayBeInitialized();
VariableControlFlowState variableDeclarationInfo = VariableControlFlowState.create(isInitialized, true);
exitInstructionData.put(variable, variableDeclarationInfo);
}
}
return exitInstructionData;
}
// variable use
@NotNull
public Map>> getVariableUseStatusData() {
return pseudocodeVariableDataCollector.collectData(
BACKWARD, /*mergeDataWithLocalDeclarations=*/ true,
new InstructionDataMergeStrategy() {
@NotNull
@Override
public Edges> invoke(
@NotNull Instruction instruction,
@NotNull Collection> incomingEdgesData
) {
Map enterResult = Maps.newHashMap();
for (Map edgeData : incomingEdgesData) {
for (Map.Entry entry : edgeData.entrySet()) {
VariableDescriptor variableDescriptor = entry.getKey();
VariableUseState variableUseState = entry.getValue();
enterResult.put(variableDescriptor, variableUseState.merge(enterResult.get(variableDescriptor)));
}
}
VariableDescriptor variableDescriptor = PseudocodeUtil.extractVariableDescriptorIfAny(
instruction, true, bindingContext);
if (variableDescriptor == null ||
(!(instruction instanceof ReadValueInstruction) && !(instruction instanceof WriteValueInstruction))) {
return new Edges>(enterResult, enterResult);
}
Map exitResult = Maps.newHashMap(enterResult);
if (instruction instanceof ReadValueInstruction) {
exitResult.put(variableDescriptor, VariableUseState.READ);
}
else { //instruction instanceof WriteValueInstruction
VariableUseState variableUseState = enterResult.get(variableDescriptor);
if (variableUseState == null) {
variableUseState = VariableUseState.UNUSED;
}
switch (variableUseState) {
case UNUSED:
case ONLY_WRITTEN_NEVER_READ:
exitResult.put(variableDescriptor, VariableUseState.ONLY_WRITTEN_NEVER_READ);
break;
case WRITTEN_AFTER_READ:
case READ:
exitResult.put(variableDescriptor, VariableUseState.WRITTEN_AFTER_READ);
}
}
return new Edges>(enterResult, exitResult);
}
}
);
}
private enum TriInitState {
INITIALIZED("I"), UNKNOWN("I?"), NOT_INITIALIZED("");
private final String s;
TriInitState(String s) {
this.s = s;
}
private TriInitState merge(@NotNull TriInitState other) {
if (this == other) return this;
return UNKNOWN;
}
@Override
public String toString() {
return s;
}
}
public static class VariableControlFlowState {
public final TriInitState initState;
public final boolean isDeclared;
private VariableControlFlowState(TriInitState initState, boolean isDeclared) {
this.initState = initState;
this.isDeclared = isDeclared;
}
private static final VariableControlFlowState VS_IT = new VariableControlFlowState(TriInitState.INITIALIZED, true);
private static final VariableControlFlowState VS_IF = new VariableControlFlowState(TriInitState.INITIALIZED, false);
private static final VariableControlFlowState VS_UT = new VariableControlFlowState(TriInitState.UNKNOWN, true);
private static final VariableControlFlowState VS_UF = new VariableControlFlowState(TriInitState.UNKNOWN, false);
private static final VariableControlFlowState VS_NT = new VariableControlFlowState(TriInitState.NOT_INITIALIZED, true);
private static final VariableControlFlowState VS_NF = new VariableControlFlowState(TriInitState.NOT_INITIALIZED, false);
private static VariableControlFlowState create(TriInitState initState, boolean isDeclared) {
switch (initState) {
case INITIALIZED: return isDeclared ? VS_IT : VS_IF;
case UNKNOWN: return isDeclared ? VS_UT : VS_UF;
default: return isDeclared ? VS_NT : VS_NF;
}
}
private static VariableControlFlowState create(boolean isInitialized, boolean isDeclared) {
return create(isInitialized ? TriInitState.INITIALIZED : TriInitState.NOT_INITIALIZED, isDeclared);
}
private static VariableControlFlowState create(boolean isInitialized) {
return create(isInitialized, false);
}
private static VariableControlFlowState create(boolean isDeclaredHere, @Nullable VariableControlFlowState mergedEdgesData) {
return create(true, isDeclaredHere || (mergedEdgesData != null && mergedEdgesData.isDeclared));
}
public boolean definitelyInitialized() {
return initState == TriInitState.INITIALIZED;
}
public boolean mayBeInitialized() {
return initState != TriInitState.NOT_INITIALIZED;
}
@Override
public String toString() {
if (initState == TriInitState.NOT_INITIALIZED && !isDeclared) return "-";
return initState + (isDeclared ? "D" : "");
}
}
public enum VariableUseState {
READ(3),
WRITTEN_AFTER_READ(2),
ONLY_WRITTEN_NEVER_READ(1),
UNUSED(0);
private final int priority;
VariableUseState(int priority) {
this.priority = priority;
}
private VariableUseState merge(@Nullable VariableUseState variableUseState) {
if (variableUseState == null || priority > variableUseState.priority) return this;
return variableUseState;
}
public static boolean isUsed(@Nullable VariableUseState variableUseState) {
return variableUseState != null && variableUseState != UNUSED;
}
}
}