org.jetbrains.jet.lang.cfg.JetFlowInformationProvider Maven / Gradle / Ivy
/*
* Copyright 2010-2013 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.jet.lang.cfg;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import com.intellij.psi.PsiElement;
import com.intellij.psi.tree.IElementType;
import com.intellij.psi.util.PsiTreeUtil;
import kotlin.Function1;
import kotlin.Function3;
import kotlin.Unit;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.jet.lang.cfg.pseudocodeTraverser.Edges;
import org.jetbrains.jet.lang.cfg.pseudocodeTraverser.PseudocodeTraverserPackage;
import org.jetbrains.jet.lang.cfg.PseudocodeVariablesData.VariableInitState;
import org.jetbrains.jet.lang.cfg.PseudocodeVariablesData.VariableUseState;
import org.jetbrains.jet.lang.cfg.pseudocode.*;
import org.jetbrains.jet.lang.cfg.pseudocodeTraverser.TraversalOrder;
import org.jetbrains.jet.lang.descriptors.*;
import org.jetbrains.jet.lang.diagnostics.Diagnostic;
import org.jetbrains.jet.lang.diagnostics.DiagnosticFactory;
import org.jetbrains.jet.lang.diagnostics.Errors;
import org.jetbrains.jet.lang.psi.*;
import org.jetbrains.jet.lang.resolve.BindingContext;
import org.jetbrains.jet.lang.resolve.BindingContextUtils;
import org.jetbrains.jet.lang.resolve.BindingTrace;
import org.jetbrains.jet.lang.resolve.DescriptorUtils;
import org.jetbrains.jet.lang.resolve.calls.TailRecursionKind;
import org.jetbrains.jet.lang.resolve.calls.model.ResolvedCall;
import org.jetbrains.jet.lang.resolve.scopes.receivers.ExpressionReceiver;
import org.jetbrains.jet.lang.resolve.scopes.receivers.ReceiverValue;
import org.jetbrains.jet.lang.resolve.scopes.receivers.ThisReceiver;
import org.jetbrains.jet.lang.types.JetType;
import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
import org.jetbrains.jet.lexer.JetTokens;
import org.jetbrains.jet.plugin.MainFunctionDetector;
import java.util.*;
import static org.jetbrains.jet.lang.cfg.PseudocodeVariablesData.VariableUseState.*;
import static org.jetbrains.jet.lang.cfg.pseudocodeTraverser.TraversalOrder.FORWARD;
import static org.jetbrains.jet.lang.diagnostics.Errors.*;
import static org.jetbrains.jet.lang.resolve.BindingContext.*;
import static org.jetbrains.jet.lang.resolve.calls.TailRecursionKind.*;
import static org.jetbrains.jet.lang.types.TypeUtils.NO_EXPECTED_TYPE;
import static org.jetbrains.jet.lang.types.TypeUtils.noExpectedType;
public class JetFlowInformationProvider {
private final JetElement subroutine;
private final Pseudocode pseudocode;
private final BindingTrace trace;
private PseudocodeVariablesData pseudocodeVariablesData;
private JetFlowInformationProvider(
@NotNull JetElement declaration,
@NotNull BindingTrace trace,
@NotNull Pseudocode pseudocode
) {
this.subroutine = declaration;
this.trace = trace;
this.pseudocode = pseudocode;
}
public JetFlowInformationProvider(
@NotNull JetElement declaration,
@NotNull BindingTrace trace
) {
this(declaration, trace, new JetControlFlowProcessor(trace).generatePseudocode(declaration));
}
public PseudocodeVariablesData getPseudocodeVariablesData() {
if (pseudocodeVariablesData == null) {
pseudocodeVariablesData = new PseudocodeVariablesData(pseudocode, trace.getBindingContext());
}
return pseudocodeVariablesData;
}
public void checkForLocalClassOrObjectMode() {
// Local classes and objects are analyzed twice: when TopDownAnalyzer processes it and as a part of its container.
// Almost all checks can be done when the container is analyzed
// except recording initialized variables (this information is needed for DeclarationChecker).
recordInitializedVariables();
}
public void checkDeclaration() {
recordInitializedVariables();
checkLocalFunctions();
markUninitializedVariables();
markUnusedVariables();
markUnusedLiteralsInBlock();
}
public void checkFunction(@Nullable JetType expectedReturnType) {
checkDefiniteReturn(expectedReturnType != null ? expectedReturnType : NO_EXPECTED_TYPE);
markTailCalls();
}
private void collectReturnExpressions(@NotNull final Collection returnedExpressions) {
final Set instructions = Sets.newHashSet(pseudocode.getInstructions());
SubroutineExitInstruction exitInstruction = pseudocode.getExitInstruction();
for (Instruction previousInstruction : exitInstruction.getPreviousInstructions()) {
previousInstruction.accept(new InstructionVisitor() {
@Override
public void visitReturnValue(ReturnValueInstruction instruction) {
if (instructions.contains(instruction)) { //exclude non-local return expressions
returnedExpressions.add(instruction.getElement());
}
}
@Override
public void visitReturnNoValue(ReturnNoValueInstruction instruction) {
if (instructions.contains(instruction)) {
returnedExpressions.add(instruction.getElement());
}
}
@Override
public void visitJump(AbstractJumpInstruction instruction) {
// Nothing
}
@Override
public void visitUnconditionalJump(UnconditionalJumpInstruction instruction) {
redirectToPrevInstructions(instruction);
}
private void redirectToPrevInstructions(Instruction instruction) {
for (Instruction previousInstruction : instruction.getPreviousInstructions()) {
previousInstruction.accept(this);
}
}
@Override
public void visitNondeterministicJump(NondeterministicJumpInstruction instruction) {
redirectToPrevInstructions(instruction);
}
@Override
public void visitMarkInstruction(MarkInstruction instruction) {
redirectToPrevInstructions(instruction);
}
@Override
public void visitInstruction(Instruction instruction) {
if (instruction instanceof JetElementInstruction) {
JetElementInstruction elementInstruction = (JetElementInstruction) instruction;
returnedExpressions.add(elementInstruction.getElement());
}
else {
throw new IllegalStateException(instruction + " precedes the exit point");
}
}
});
}
}
private void checkLocalFunctions() {
for (LocalFunctionDeclarationInstruction localDeclarationInstruction : pseudocode.getLocalDeclarations()) {
JetElement element = localDeclarationInstruction.getElement();
if (element instanceof JetDeclarationWithBody) {
JetDeclarationWithBody localDeclaration = (JetDeclarationWithBody) element;
if (localDeclaration instanceof JetFunctionLiteral) continue;
CallableDescriptor functionDescriptor =
(CallableDescriptor) trace.getBindingContext().get(BindingContext.DECLARATION_TO_DESCRIPTOR, localDeclaration);
JetType expectedType = functionDescriptor != null ? functionDescriptor.getReturnType() : null;
JetFlowInformationProvider providerForLocalDeclaration =
new JetFlowInformationProvider(localDeclaration, trace, localDeclarationInstruction.getBody());
providerForLocalDeclaration.checkFunction(expectedType);
}
}
}
public void checkDefiniteReturn(final @NotNull JetType expectedReturnType) {
assert subroutine instanceof JetDeclarationWithBody;
JetDeclarationWithBody function = (JetDeclarationWithBody) subroutine;
JetExpression bodyExpression = function.getBodyExpression();
if (bodyExpression == null) return;
List returnedExpressions = Lists.newArrayList();
collectReturnExpressions(returnedExpressions);
final boolean blockBody = function.hasBlockBody();
final Set rootUnreachableElements = collectUnreachableCode();
for (JetElement element : rootUnreachableElements) {
trace.report(UNREACHABLE_CODE.on(element));
}
final boolean[] noReturnError = new boolean[] { false };
for (JetElement returnedExpression : returnedExpressions) {
returnedExpression.accept(new JetVisitorVoid() {
@Override
public void visitReturnExpression(@NotNull JetReturnExpression expression) {
if (!blockBody) {
trace.report(RETURN_IN_FUNCTION_WITH_EXPRESSION_BODY.on(expression));
}
}
@Override
public void visitExpression(@NotNull JetExpression expression) {
if (blockBody && !noExpectedType(expectedReturnType)
&& !KotlinBuiltIns.getInstance().isUnit(expectedReturnType)
&& !rootUnreachableElements.contains(expression)) {
noReturnError[0] = true;
}
}
});
}
if (noReturnError[0]) {
trace.report(NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY.on(function));
}
}
private Set collectUnreachableCode() {
Collection unreachableElements = Lists.newArrayList();
for (Instruction deadInstruction : pseudocode.getDeadInstructions()) {
if (!(deadInstruction instanceof JetElementInstruction) || deadInstruction instanceof LoadUnitValueInstruction) continue;
JetElement element = ((JetElementInstruction) deadInstruction).getElement();
if (deadInstruction instanceof JumpInstruction) {
boolean isJumpElement = element instanceof JetBreakExpression
|| element instanceof JetContinueExpression
|| element instanceof JetReturnExpression
|| element instanceof JetThrowExpression;
if (!isJumpElement) continue;
}
unreachableElements.add(element);
}
// This is needed in order to highlight only '1 < 2' and not '1', '<' and '2' as well
return JetPsiUtil.findRootExpressions(unreachableElements);
}
////////////////////////////////////////////////////////////////////////////////
// Uninitialized variables analysis
public void markUninitializedVariables() {
final Collection varWithUninitializedErrorGenerated = Sets.newHashSet();
final Collection varWithValReassignErrorGenerated = Sets.newHashSet();
final boolean processClassOrObject = subroutine instanceof JetClassOrObject;
PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
Map>> initializers =
pseudocodeVariablesData.getVariableInitializers();
final Set declaredVariables = pseudocodeVariablesData.getDeclaredVariables(pseudocode, true);
final LexicalScopeVariableInfo lexicalScopeVariableInfo = pseudocodeVariablesData.getLexicalScopeVariableInfo();
final Map reportedDiagnosticMap = Maps.newHashMap();
PseudocodeTraverserPackage.traverse(
pseudocode, FORWARD, initializers,
new InstructionDataAnalyzeStrategy>() {
@Override
public void execute(
@NotNull Instruction instruction,
@Nullable Map in,
@Nullable Map out
) {
assert in != null && out != null;
VariableInitContext ctxt =
new VariableInitContext(instruction, reportedDiagnosticMap, in, out, lexicalScopeVariableInfo);
if (ctxt.variableDescriptor == null) return;
if (instruction instanceof ReadValueInstruction) {
JetElement element = ((ReadValueInstruction) instruction).getElement();
boolean error = checkBackingField(ctxt, element);
if (!error && declaredVariables.contains(ctxt.variableDescriptor)) {
checkIsInitialized(ctxt, element, varWithUninitializedErrorGenerated);
}
return;
}
if (!(instruction instanceof WriteValueInstruction)) return;
JetElement element = ((WriteValueInstruction) instruction).getlValue();
boolean error = checkBackingField(ctxt, element);
if (!(element instanceof JetExpression)) return;
if (!error) {
error = checkValReassignment(ctxt, (JetExpression) element, varWithValReassignErrorGenerated);
}
if (!error && processClassOrObject) {
error = checkAssignmentBeforeDeclaration(ctxt, (JetExpression) element);
}
if (!error && processClassOrObject) {
checkInitializationUsingBackingField(ctxt, (JetExpression) element);
}
}
}
);
}
public void recordInitializedVariables() {
PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
Pseudocode pseudocode = pseudocodeVariablesData.getPseudocode();
Map>> initializers =
pseudocodeVariablesData.getVariableInitializers();
recordInitializedVariables(pseudocode, initializers);
for (LocalFunctionDeclarationInstruction instruction : pseudocode.getLocalDeclarations()) {
recordInitializedVariables(instruction.getBody(), initializers);
}
}
private void checkIsInitialized(
@NotNull VariableInitContext ctxt,
@NotNull JetElement element,
@NotNull Collection varWithUninitializedErrorGenerated
) {
if (!(element instanceof JetSimpleNameExpression)) return;
boolean isInitialized = ctxt.exitInitState.isInitialized;
VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
if (variableDescriptor instanceof PropertyDescriptor) {
if (!trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor)) {
isInitialized = true;
}
}
if (!isInitialized && !varWithUninitializedErrorGenerated.contains(variableDescriptor)) {
if (!(variableDescriptor instanceof PropertyDescriptor)) {
varWithUninitializedErrorGenerated.add(variableDescriptor);
}
if (variableDescriptor instanceof ValueParameterDescriptor) {
report(Errors.UNINITIALIZED_PARAMETER.on((JetSimpleNameExpression) element,
(ValueParameterDescriptor) variableDescriptor), ctxt);
}
else {
report(Errors.UNINITIALIZED_VARIABLE.on((JetSimpleNameExpression) element, variableDescriptor), ctxt);
}
}
}
private boolean checkValReassignment(
@NotNull VariableInitContext ctxt,
@NotNull JetExpression expression,
@NotNull Collection varWithValReassignErrorGenerated
) {
VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
if (JetPsiUtil.isBackingFieldReference(expression) && variableDescriptor instanceof PropertyDescriptor) {
PropertyDescriptor propertyDescriptor = (PropertyDescriptor) variableDescriptor;
JetPropertyAccessor accessor = PsiTreeUtil.getParentOfType(expression, JetPropertyAccessor.class);
if (accessor != null) {
DeclarationDescriptor accessorDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, accessor);
if (propertyDescriptor.getGetter() == accessorDescriptor) {
//val can be reassigned through backing field inside its own getter
return false;
}
}
}
boolean isInitializedNotHere = ctxt.enterInitState.isInitialized;
boolean hasBackingField = true;
if (variableDescriptor instanceof PropertyDescriptor) {
hasBackingField = trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor);
}
if (variableDescriptor.isVar() && variableDescriptor instanceof PropertyDescriptor) {
DeclarationDescriptor descriptor = BindingContextUtils.getEnclosingDescriptor(trace.getBindingContext(), expression);
PropertySetterDescriptor setterDescriptor = ((PropertyDescriptor) variableDescriptor).getSetter();
if (Visibilities.isVisible(variableDescriptor, descriptor) && setterDescriptor != null
&& !Visibilities.isVisible(setterDescriptor, descriptor)) {
report(Errors.INVISIBLE_SETTER.on(expression, variableDescriptor, setterDescriptor.getVisibility(),
variableDescriptor.getContainingDeclaration()), ctxt);
return true;
}
}
if ((isInitializedNotHere || !hasBackingField) && !variableDescriptor.isVar()
&& !varWithValReassignErrorGenerated.contains(variableDescriptor)) {
boolean hasReassignMethodReturningUnit = false;
JetSimpleNameExpression operationReference = null;
PsiElement parent = expression.getParent();
if (parent instanceof JetBinaryExpression) {
operationReference = ((JetBinaryExpression) parent).getOperationReference();
}
else if (parent instanceof JetUnaryExpression) {
operationReference = ((JetUnaryExpression) parent).getOperationReference();
}
if (operationReference != null) {
DeclarationDescriptor descriptor = trace.get(BindingContext.REFERENCE_TARGET, operationReference);
if (descriptor instanceof FunctionDescriptor) {
if (KotlinBuiltIns.getInstance().isUnit(((FunctionDescriptor) descriptor).getReturnType())) {
hasReassignMethodReturningUnit = true;
}
}
if (descriptor == null) {
Collection descriptors =
trace.get(BindingContext.AMBIGUOUS_REFERENCE_TARGET, operationReference);
if (descriptors != null) {
for (DeclarationDescriptor referenceDescriptor : descriptors) {
if (KotlinBuiltIns.getInstance().isUnit(((FunctionDescriptor) referenceDescriptor).getReturnType())) {
hasReassignMethodReturningUnit = true;
}
}
}
}
}
if (!hasReassignMethodReturningUnit) {
varWithValReassignErrorGenerated.add(variableDescriptor);
report(Errors.VAL_REASSIGNMENT.on(expression, variableDescriptor), ctxt);
return true;
}
}
return false;
}
private boolean checkAssignmentBeforeDeclaration(@NotNull VariableInitContext ctxt, @NotNull JetExpression expression) {
if (!ctxt.enterInitState.isDeclared && !ctxt.exitInitState.isDeclared
&& !ctxt.enterInitState.isInitialized && ctxt.exitInitState.isInitialized) {
report(Errors.INITIALIZATION_BEFORE_DECLARATION.on(expression, ctxt.variableDescriptor), ctxt);
return true;
}
return false;
}
private boolean checkInitializationUsingBackingField(@NotNull VariableInitContext ctxt, @NotNull JetExpression expression) {
VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
if (variableDescriptor instanceof PropertyDescriptor && !ctxt.enterInitState.isInitialized && ctxt.exitInitState.isInitialized) {
if (!variableDescriptor.isVar()) return false;
if (!trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor)) return false;
PsiElement property = BindingContextUtils.descriptorToDeclaration(trace.getBindingContext(), variableDescriptor);
assert property instanceof JetProperty;
if (((PropertyDescriptor) variableDescriptor).getModality() == Modality.FINAL && ((JetProperty) property).getSetter() == null) {
return false;
}
JetExpression variable = expression;
if (expression instanceof JetDotQualifiedExpression) {
if (((JetDotQualifiedExpression) expression).getReceiverExpression() instanceof JetThisExpression) {
variable = ((JetDotQualifiedExpression) expression).getSelectorExpression();
}
}
if (variable instanceof JetSimpleNameExpression) {
JetSimpleNameExpression simpleNameExpression = (JetSimpleNameExpression) variable;
if (simpleNameExpression.getReferencedNameElementType() != JetTokens.FIELD_IDENTIFIER) {
if (((PropertyDescriptor) variableDescriptor).getModality() != Modality.FINAL) {
report(Errors.INITIALIZATION_USING_BACKING_FIELD_OPEN_SETTER.on(expression, variableDescriptor), ctxt);
}
else {
report(Errors.INITIALIZATION_USING_BACKING_FIELD_CUSTOM_SETTER.on(expression, variableDescriptor), ctxt);
}
return true;
}
}
}
return false;
}
private boolean checkBackingField(@NotNull VariableContext cxtx, @NotNull JetElement element) {
VariableDescriptor variableDescriptor = cxtx.variableDescriptor;
boolean[] error = new boolean[1];
if (!isCorrectBackingFieldReference(element, cxtx, error, true)) return false;
if (error[0]) return true;
if (!(variableDescriptor instanceof PropertyDescriptor)) {
report(Errors.NOT_PROPERTY_BACKING_FIELD.on(element), cxtx);
return true;
}
PsiElement property = BindingContextUtils.descriptorToDeclaration(trace.getBindingContext(), variableDescriptor);
boolean insideSelfAccessors = PsiTreeUtil.isAncestor(property, element, false);
if (!trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor) &&
// not to generate error in accessors of abstract properties, there is one: declared accessor of abstract property
!insideSelfAccessors) {
if (((PropertyDescriptor) variableDescriptor).getModality() == Modality.ABSTRACT) {
report(NO_BACKING_FIELD_ABSTRACT_PROPERTY.on(element), cxtx);
}
else {
report(NO_BACKING_FIELD_CUSTOM_ACCESSORS.on(element), cxtx);
}
return true;
}
if (insideSelfAccessors) return false;
DeclarationDescriptor declarationDescriptor = BindingContextUtils.getEnclosingDescriptor(trace.getBindingContext(), element);
DeclarationDescriptor containingDeclaration = variableDescriptor.getContainingDeclaration();
if ((containingDeclaration instanceof ClassDescriptor)
&& DescriptorUtils.isAncestor(containingDeclaration, declarationDescriptor, false)) {
return false;
}
report(Errors.INACCESSIBLE_BACKING_FIELD.on(element), cxtx);
return true;
}
private boolean isCorrectBackingFieldReference(
@Nullable JetElement element,
VariableContext ctxt,
boolean[] error,
boolean reportError
) {
error[0] = false;
if (JetPsiUtil.isBackingFieldReference(element)) {
return true;
}
if (element instanceof JetDotQualifiedExpression && isCorrectBackingFieldReference(
((JetDotQualifiedExpression) element).getSelectorExpression(), ctxt, error, false)) {
if (((JetDotQualifiedExpression) element).getReceiverExpression() instanceof JetThisExpression) {
return true;
}
error[0] = true;
if (reportError) {
report(Errors.INACCESSIBLE_BACKING_FIELD.on(element), ctxt);
}
}
return false;
}
private void recordInitializedVariables(
@NotNull Pseudocode pseudocode,
@NotNull Map>> initializersMap
) {
Edges> initializers = initializersMap.get(pseudocode.getExitInstruction());
Set declaredVariables = getPseudocodeVariablesData().getDeclaredVariables(pseudocode, false);
for (VariableDescriptor variable : declaredVariables) {
if (variable instanceof PropertyDescriptor) {
PseudocodeVariablesData.VariableInitState variableInitState = initializers.getIncoming().get(variable);
if (variableInitState == null) return;
trace.record(BindingContext.IS_INITIALIZED, (PropertyDescriptor) variable, variableInitState.isInitialized);
}
}
}
////////////////////////////////////////////////////////////////////////////////
// "Unused variable" & "unused value" analyses
public void markUnusedVariables() {
final PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
Map>> variableStatusData =
pseudocodeVariablesData.getVariableUseStatusData();
final Map reportedDiagnosticMap = Maps.newHashMap();
InstructionDataAnalyzeStrategy> variableStatusAnalyzeStrategy =
new InstructionDataAnalyzeStrategy>() {
@Override
public void execute(
@NotNull Instruction instruction,
@Nullable Map in,
@Nullable Map out
) {
assert in != null && out != null;
VariableContext ctxt = new VariableUseContext(instruction, reportedDiagnosticMap, in, out);
Set declaredVariables =
pseudocodeVariablesData.getDeclaredVariables(instruction.getOwner(), false);
VariableDescriptor variableDescriptor = PseudocodeUtil.extractVariableDescriptorIfAny(
instruction, false, trace.getBindingContext());
if (variableDescriptor == null || !declaredVariables.contains(variableDescriptor)
|| !DescriptorUtils.isLocal(variableDescriptor.getContainingDeclaration(), variableDescriptor)) {
return;
}
PseudocodeVariablesData.VariableUseState variableUseState = in.get(variableDescriptor);
if (instruction instanceof WriteValueInstruction) {
if (trace.get(CAPTURED_IN_CLOSURE, variableDescriptor) != null) return;
JetElement element = ((WriteValueInstruction) instruction).getElement();
if (variableUseState != READ) {
if (element instanceof JetBinaryExpression &&
((JetBinaryExpression) element).getOperationToken() == JetTokens.EQ) {
JetExpression right = ((JetBinaryExpression) element).getRight();
if (right != null) {
report(Errors.UNUSED_VALUE.on(right, right, variableDescriptor), ctxt);
}
}
else if (element instanceof JetPostfixExpression) {
IElementType operationToken =
((JetPostfixExpression) element).getOperationReference().getReferencedNameElementType();
if (operationToken == JetTokens.PLUSPLUS || operationToken == JetTokens.MINUSMINUS) {
report(Errors.UNUSED_CHANGED_VALUE.on(element, element), ctxt);
}
}
}
}
else if (instruction instanceof VariableDeclarationInstruction) {
JetDeclaration element = ((VariableDeclarationInstruction) instruction).getVariableDeclarationElement();
if (!(element instanceof JetNamedDeclaration)) return;
PsiElement nameIdentifier = ((JetNamedDeclaration) element).getNameIdentifier();
if (nameIdentifier == null) return;
if (!VariableUseState.isUsed(variableUseState)) {
if (JetPsiUtil.isVariableNotParameterDeclaration(element)) {
report(Errors.UNUSED_VARIABLE.on((JetNamedDeclaration) element, variableDescriptor), ctxt);
}
else if (element instanceof JetParameter) {
PsiElement psiElement = element.getParent().getParent();
if (psiElement instanceof JetFunction) {
MainFunctionDetector mainFunctionDetector = new MainFunctionDetector(trace.getBindingContext());
boolean isMain = (psiElement instanceof JetNamedFunction) && mainFunctionDetector.isMain((JetNamedFunction) psiElement);
if (psiElement instanceof JetFunctionLiteral) return;
DeclarationDescriptor descriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, psiElement);
assert descriptor instanceof FunctionDescriptor : psiElement.getText();
FunctionDescriptor functionDescriptor = (FunctionDescriptor) descriptor;
if (!isMain && !functionDescriptor.getModality().isOverridable()
&& functionDescriptor.getOverriddenDescriptors().isEmpty()) {
report(Errors.UNUSED_PARAMETER.on((JetParameter) element, variableDescriptor), ctxt);
}
}
}
}
else if (variableUseState == ONLY_WRITTEN_NEVER_READ && JetPsiUtil.isVariableNotParameterDeclaration(element)) {
report(Errors.ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE.on((JetNamedDeclaration) element, variableDescriptor), ctxt);
}
else if (variableUseState == WRITTEN_AFTER_READ && element instanceof JetVariableDeclaration) {
if (element instanceof JetProperty) {
JetExpression initializer = ((JetProperty) element).getInitializer();
if (initializer != null) {
report(Errors.VARIABLE_WITH_REDUNDANT_INITIALIZER.on(initializer, variableDescriptor), ctxt);
}
}
else if (element instanceof JetMultiDeclarationEntry) {
report(VARIABLE_WITH_REDUNDANT_INITIALIZER.on(element, variableDescriptor), ctxt);
}
}
}
}
};
PseudocodeTraverserPackage.traverse(pseudocode, TraversalOrder.BACKWARD, variableStatusData, variableStatusAnalyzeStrategy);
}
////////////////////////////////////////////////////////////////////////////////
// "Unused literals" in block
public void markUnusedLiteralsInBlock() {
final Map reportedDiagnosticMap = Maps.newHashMap();
PseudocodeTraverserPackage.traverse(
pseudocode, FORWARD, new FunctionVoid1() {
@Override
public void execute(@NotNull Instruction instruction) {
if (!(instruction instanceof ReadValueInstruction)) return;
VariableContext ctxt = new VariableContext(instruction, reportedDiagnosticMap);
JetElement element =
((ReadValueInstruction) instruction).getElement();
if (!(element instanceof JetFunctionLiteralExpression
|| element instanceof JetConstantExpression
|| element instanceof JetStringTemplateExpression
|| element instanceof JetSimpleNameExpression)) {
return;
}
PsiElement parent = element.getParent();
if (parent instanceof JetBlockExpression) {
if (!JetPsiUtil.isImplicitlyUsed(element)) {
if (element instanceof JetFunctionLiteralExpression) {
report(Errors.UNUSED_FUNCTION_LITERAL.on((JetFunctionLiteralExpression) element), ctxt);
}
else {
report(Errors.UNUSED_EXPRESSION.on(element), ctxt);
}
}
}
}
}
);
}
////////////////////////////////////////////////////////////////////////////////
// Tail calls
public void markTailCalls() {
final DeclarationDescriptor subroutineDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, subroutine);
if (!(subroutineDescriptor instanceof FunctionDescriptor)) return;
if (!KotlinBuiltIns.getInstance().isTailRecursive(subroutineDescriptor)) return;
// finally blocks are copied which leads to multiple diagnostics reported on one instruction
class KindAndCall {
TailRecursionKind kind;
ResolvedCall call;
KindAndCall(TailRecursionKind kind, ResolvedCall call) {
this.kind = kind;
this.call = call;
}
}
final Map calls = new HashMap();
PseudocodeTraverserPackage.traverse(
pseudocode,
FORWARD,
new FunctionVoid1() {
public void execute(@NotNull Instruction instruction) {
if (!(instruction instanceof CallInstruction)) return;
CallInstruction callInstruction = (CallInstruction) instruction;
ResolvedCall resolvedCall = trace.get(RESOLVED_CALL, callInstruction.getElement());
if (resolvedCall == null) return;
// is this a recursive call?
CallableDescriptor functionDescriptor = resolvedCall.getResultingDescriptor();
if (!functionDescriptor.getOriginal().equals(subroutineDescriptor)) return;
JetElement element = callInstruction.getElement();
//noinspection unchecked
JetExpression parent = PsiTreeUtil.getParentOfType(
element,
JetTryExpression.class, JetFunction.class, JetClassInitializer.class
);
if (parent instanceof JetTryExpression) {
// We do not support tail calls Collections.singletonMap() try-catch-finally, for simplicity of the mental model
// very few cases there would be real tail-calls, and it's often not so easy for the user to see why
calls.put(element, new KindAndCall(IN_TRY, resolvedCall));
return;
}
boolean isTail = PseudocodeTraverserPackage.traverseFollowingInstructions(
callInstruction,
new HashSet(),
FORWARD,
new TailRecursionDetector(subroutine, callInstruction)
);
boolean sameThisObject = sameThisObject(resolvedCall);
TailRecursionKind kind = isTail && sameThisObject ? TAIL_CALL : NON_TAIL;
KindAndCall kindAndCall = calls.get(element);
calls.put(element,
new KindAndCall(
combineKinds(kind, kindAndCall == null ? null : kindAndCall.kind),
resolvedCall
)
);
}
}
);
boolean hasTailCalls = false;
for (Map.Entry entry : calls.entrySet()) {
JetElement element = entry.getKey();
KindAndCall kindAndCall = entry.getValue();
switch (kindAndCall.kind) {
case TAIL_CALL:
trace.record(TAIL_RECURSION_CALL, kindAndCall.call, TailRecursionKind.TAIL_CALL);
hasTailCalls = true;
break;
case IN_TRY:
trace.report(Errors.TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED.on(element));
break;
case NON_TAIL:
trace.report(Errors.NON_TAIL_RECURSIVE_CALL.on(element));
break;
}
}
if (!hasTailCalls) {
trace.report(Errors.NO_TAIL_CALLS_FOUND.on((JetNamedFunction) subroutine));
}
}
private boolean sameThisObject(ResolvedCall resolvedCall) {
// A tail call is not allowed to change dispatch receiver
// class C {
// fun foo(other: C) {
// other.foo(this) // not a tail call
// }
// }
ReceiverParameterDescriptor thisObject = resolvedCall.getResultingDescriptor().getExpectedThisObject();
ReceiverValue thisObjectValue = resolvedCall.getThisObject();
if (thisObject == null || !thisObjectValue.exists()) return true;
DeclarationDescriptor classDescriptor = null;
if (thisObjectValue instanceof ThisReceiver) {
// foo() -- implicit receiver
classDescriptor = ((ThisReceiver) thisObjectValue).getDeclarationDescriptor();
}
else if (thisObjectValue instanceof ExpressionReceiver) {
JetExpression expression = JetPsiUtil.deparenthesize(((ExpressionReceiver) thisObjectValue).getExpression());
if (expression instanceof JetThisExpression) {
// this.foo() -- explicit receiver
JetThisExpression thisExpression = (JetThisExpression) expression;
classDescriptor = trace.get(BindingContext.REFERENCE_TARGET, thisExpression.getInstanceReference());
}
}
return thisObject.getContainingDeclaration() == classDescriptor;
}
private static TailRecursionKind combineKinds(TailRecursionKind kind, @Nullable TailRecursionKind existingKind) {
TailRecursionKind resultingKind;
if (existingKind == null || existingKind == kind) {
resultingKind = kind;
}
else {
if (check(kind, existingKind, IN_TRY, TAIL_CALL)) {
resultingKind = IN_TRY;
}
else if (check(kind, existingKind, IN_TRY, NON_TAIL)) {
resultingKind = IN_TRY;
}
else {
// TAIL_CALL, NON_TAIL
resultingKind = NON_TAIL;
}
}
return resultingKind;
}
private static boolean check(Object a, Object b, Object x, Object y) {
return (a == x && b == y) || (a == y && b == x);
}
////////////////////////////////////////////////////////////////////////////////
// Utility classes and methods
/**
* The method provides reporting of the same diagnostic only once for copied instructions
* (depends on whether it should be reported for all or only for one of the copies)
*/
private void report(
@NotNull Diagnostic diagnostic,
@NotNull VariableContext ctxt
) {
Instruction instruction = ctxt.instruction;
if (instruction.getCopies().isEmpty()) {
trace.report(diagnostic);
return;
}
Map previouslyReported = ctxt.reportedDiagnosticMap;
previouslyReported.put(instruction, diagnostic.getFactory());
boolean alreadyReported = false;
boolean sameErrorForAllCopies = true;
for (Instruction copy : instruction.getCopies()) {
DiagnosticFactory previouslyReportedErrorFactory = previouslyReported.get(copy);
if (previouslyReportedErrorFactory != null) {
alreadyReported = true;
}
if (previouslyReportedErrorFactory != diagnostic.getFactory()) {
sameErrorForAllCopies = false;
}
}
if (mustBeReportedOnAllCopies(diagnostic.getFactory())) {
if (sameErrorForAllCopies) {
trace.report(diagnostic);
}
}
else {
//only one reporting required
if (!alreadyReported) {
trace.report(diagnostic);
}
}
}
private static boolean mustBeReportedOnAllCopies(@NotNull DiagnosticFactory diagnosticFactory) {
return diagnosticFactory == UNUSED_VARIABLE
|| diagnosticFactory == UNUSED_PARAMETER
|| diagnosticFactory == UNUSED_CHANGED_VALUE;
}
private class VariableContext {
final Map reportedDiagnosticMap;
final Instruction instruction;
final VariableDescriptor variableDescriptor;
private VariableContext(
@NotNull Instruction instruction,
@NotNull Map map
) {
this.instruction = instruction;
reportedDiagnosticMap = map;
variableDescriptor = PseudocodeUtil.extractVariableDescriptorIfAny(instruction, true, trace.getBindingContext());
}
}
private class VariableInitContext extends VariableContext {
final VariableInitState enterInitState;
final VariableInitState exitInitState;
private VariableInitContext(
@NotNull Instruction instruction,
@NotNull Map map,
@NotNull Map in,
@NotNull Map out,
@NotNull LexicalScopeVariableInfo lexicalScopeVariableInfo
) {
super(instruction, map);
enterInitState = initialize(variableDescriptor, lexicalScopeVariableInfo, in);
exitInitState = initialize(variableDescriptor, lexicalScopeVariableInfo, out);
}
private VariableInitState initialize(
VariableDescriptor variableDescriptor,
LexicalScopeVariableInfo lexicalScopeVariableInfo,
Map map
) {
if (variableDescriptor == null) return null;
VariableInitState state = map.get(variableDescriptor);
if (state != null) return state;
return PseudocodeVariablesData.getDefaultValueForInitializers(variableDescriptor, instruction, lexicalScopeVariableInfo);
}
}
private class VariableUseContext extends VariableContext {
final VariableUseState enterUseState;
final VariableUseState exitUseState;
private VariableUseContext(
@NotNull Instruction instruction,
@NotNull Map map,
@NotNull Map in,
@NotNull Map out
) {
super(instruction, map);
enterUseState = variableDescriptor != null ? in.get(variableDescriptor) : null;
exitUseState = variableDescriptor != null ? out.get(variableDescriptor) : null;
}
}
//TODO after KT-4621 rewrite to Kotlin
public abstract static class InstructionDataAnalyzeStrategy implements Function3 {
@Override
public Unit invoke(Instruction instruction, D enterData, D exitData) {
execute(instruction, enterData, exitData);
return Unit.VALUE;
}
public abstract void execute(Instruction instruction, D enterData, D exitData);
}
public abstract static class FunctionVoid1 implements Function1 {
@Override
public Unit invoke(P p) {
execute(p);
return Unit.VALUE;
}
public abstract void execute(P p);
}
}
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