org.jetbrains.kotlin.cfg.ControlFlowInformationProvider Maven / Gradle / Ivy
/*
* Copyright 2010-2016 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.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.Unit;
import kotlin.jvm.functions.Function1;
import kotlin.jvm.functions.Function3;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
import org.jetbrains.kotlin.cfg.pseudocode.PseudoValue;
import org.jetbrains.kotlin.cfg.pseudocode.Pseudocode;
import org.jetbrains.kotlin.cfg.pseudocode.PseudocodeUtil;
import org.jetbrains.kotlin.cfg.pseudocode.PseudocodeUtilsKt;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.Instruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.InstructionVisitor;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.KtElementInstruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.*;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.jumps.*;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.LocalFunctionDeclarationInstruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.MarkInstruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.SubroutineExitInstruction;
import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.VariableDeclarationInstruction;
import org.jetbrains.kotlin.cfg.pseudocodeTraverser.Edges;
import org.jetbrains.kotlin.cfg.pseudocodeTraverser.PseudocodeTraverserKt;
import org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder;
import org.jetbrains.kotlin.descriptors.*;
import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptorKt;
import org.jetbrains.kotlin.diagnostics.Diagnostic;
import org.jetbrains.kotlin.diagnostics.DiagnosticFactory;
import org.jetbrains.kotlin.diagnostics.Errors;
import org.jetbrains.kotlin.idea.MainFunctionDetector;
import org.jetbrains.kotlin.lexer.KtTokens;
import org.jetbrains.kotlin.psi.*;
import org.jetbrains.kotlin.resolve.*;
import org.jetbrains.kotlin.resolve.bindingContextUtil.BindingContextUtilsKt;
import org.jetbrains.kotlin.resolve.calls.callUtil.CallUtilKt;
import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall;
import org.jetbrains.kotlin.resolve.calls.resolvedCallUtil.ResolvedCallUtilKt;
import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue;
import org.jetbrains.kotlin.types.KotlinType;
import org.jetbrains.kotlin.types.expressions.ExpressionTypingUtils;
import java.util.*;
import static org.jetbrains.kotlin.cfg.TailRecursionKind.*;
import static org.jetbrains.kotlin.cfg.VariableUseState.*;
import static org.jetbrains.kotlin.diagnostics.Errors.*;
import static org.jetbrains.kotlin.diagnostics.Errors.UNREACHABLE_CODE;
import static org.jetbrains.kotlin.resolve.BindingContext.*;
import static org.jetbrains.kotlin.types.TypeUtils.*;
public class ControlFlowInformationProvider {
private final KtElement subroutine;
private final Pseudocode pseudocode;
private final BindingTrace trace;
private PseudocodeVariablesData pseudocodeVariablesData;
private ControlFlowInformationProvider(
@NotNull KtElement declaration,
@NotNull BindingTrace trace,
@NotNull Pseudocode pseudocode
) {
this.subroutine = declaration;
this.trace = trace;
this.pseudocode = pseudocode;
}
public ControlFlowInformationProvider(
@NotNull KtElement declaration,
@NotNull BindingTrace trace
) {
this(declaration, trace, new ControlFlowProcessor(trace).generatePseudocode(declaration));
}
private 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();
markStatements();
markUnusedExpressions();
checkIfExpressions();
checkWhenExpressions();
}
public void checkFunction(@Nullable KotlinType expectedReturnType) {
UnreachableCode unreachableCode = collectUnreachableCode();
reportUnreachableCode(unreachableCode);
if (subroutine instanceof KtFunctionLiteral) return;
checkDefiniteReturn(expectedReturnType != null ? expectedReturnType : NO_EXPECTED_TYPE, unreachableCode);
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(@NotNull ReturnValueInstruction instruction) {
if (instructions.contains(instruction)) { //exclude non-local return expressions
returnedExpressions.add(instruction.getElement());
}
}
@Override
public void visitReturnNoValue(@NotNull ReturnNoValueInstruction instruction) {
if (instructions.contains(instruction)) {
returnedExpressions.add(instruction.getElement());
}
}
@Override
public void visitJump(@NotNull AbstractJumpInstruction instruction) {
// Nothing
}
@Override
public void visitUnconditionalJump(@NotNull UnconditionalJumpInstruction instruction) {
redirectToPrevInstructions(instruction);
}
private void redirectToPrevInstructions(Instruction instruction) {
for (Instruction previousInstruction : instruction.getPreviousInstructions()) {
previousInstruction.accept(this);
}
}
@Override
public void visitNondeterministicJump(@NotNull NondeterministicJumpInstruction instruction) {
redirectToPrevInstructions(instruction);
}
@Override
public void visitMarkInstruction(@NotNull MarkInstruction instruction) {
redirectToPrevInstructions(instruction);
}
@Override
public void visitInstruction(@NotNull Instruction instruction) {
if (instruction instanceof KtElementInstruction) {
KtElementInstruction elementInstruction = (KtElementInstruction) instruction;
returnedExpressions.add(elementInstruction.getElement());
}
else {
throw new IllegalStateException(instruction + " precedes the exit point");
}
}
});
}
}
private void checkLocalFunctions() {
for (LocalFunctionDeclarationInstruction localDeclarationInstruction : pseudocode.getLocalDeclarations()) {
KtElement element = localDeclarationInstruction.getElement();
if (element instanceof KtDeclarationWithBody) {
KtDeclarationWithBody localDeclaration = (KtDeclarationWithBody) element;
CallableDescriptor functionDescriptor =
(CallableDescriptor) trace.getBindingContext().get(BindingContext.DECLARATION_TO_DESCRIPTOR, localDeclaration);
KotlinType expectedType = functionDescriptor != null ? functionDescriptor.getReturnType() : null;
ControlFlowInformationProvider providerForLocalDeclaration =
new ControlFlowInformationProvider(localDeclaration, trace, localDeclarationInstruction.getBody());
providerForLocalDeclaration.checkFunction(expectedType);
}
}
}
private void checkDefiniteReturn(final @NotNull KotlinType expectedReturnType, @NotNull final UnreachableCode unreachableCode) {
assert subroutine instanceof KtDeclarationWithBody;
KtDeclarationWithBody function = (KtDeclarationWithBody) subroutine;
if (!function.hasBody()) return;
List returnedExpressions = Lists.newArrayList();
collectReturnExpressions(returnedExpressions);
final boolean blockBody = function.hasBlockBody();
final boolean[] noReturnError = new boolean[] { false };
for (KtElement returnedExpression : returnedExpressions) {
returnedExpression.accept(new KtVisitorVoid() {
@Override
public void visitReturnExpression(@NotNull KtReturnExpression expression) {
if (!blockBody) {
trace.report(RETURN_IN_FUNCTION_WITH_EXPRESSION_BODY.on(expression));
}
}
@Override
public void visitKtElement(@NotNull KtElement element) {
if (!(element instanceof KtExpression || element instanceof KtWhenCondition)) return;
if (blockBody && !noExpectedType(expectedReturnType)
&& !KotlinBuiltIns.isUnit(expectedReturnType)
&& !unreachableCode.getElements().contains(element)) {
noReturnError[0] = true;
}
}
});
}
if (noReturnError[0]) {
trace.report(NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY.on(function));
}
}
private void reportUnreachableCode(@NotNull UnreachableCode unreachableCode) {
for (KtElement element : unreachableCode.getElements()) {
trace.report(UNREACHABLE_CODE.on(element, unreachableCode.getUnreachableTextRanges(element)));
trace.record(BindingContext.UNREACHABLE_CODE, element, true);
}
}
@NotNull
private UnreachableCode collectUnreachableCode() {
Set reachableElements = Sets.newHashSet();
Set unreachableElements = Sets.newHashSet();
for (Instruction instruction : pseudocode.getInstructionsIncludingDeadCode()) {
if (!(instruction instanceof KtElementInstruction)
|| instruction instanceof LoadUnitValueInstruction
|| instruction instanceof MergeInstruction
|| (instruction instanceof MagicInstruction && ((MagicInstruction) instruction).getSynthetic())) continue;
KtElement element = ((KtElementInstruction) instruction).getElement();
if (instruction instanceof JumpInstruction) {
boolean isJumpElement = element instanceof KtBreakExpression
|| element instanceof KtContinueExpression
|| element instanceof KtReturnExpression
|| element instanceof KtThrowExpression;
if (!isJumpElement) continue;
}
if (instruction.getDead()) {
unreachableElements.add(element);
}
else {
reachableElements.add(element);
}
}
return new UnreachableCodeImpl(reachableElements, unreachableElements);
}
////////////////////////////////////////////////////////////////////////////////
// Uninitialized variables analysis
private void markUninitializedVariables() {
final Collection varWithUninitializedErrorGenerated = Sets.newHashSet();
final Collection varWithValReassignErrorGenerated = Sets.newHashSet();
final boolean processClassOrObject = subroutine instanceof KtClassOrObject;
PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
Map> initializers =
pseudocodeVariablesData.getVariableInitializers();
final Set declaredVariables = pseudocodeVariablesData.getDeclaredVariables(pseudocode, true);
final BlockScopeVariableInfo blockScopeVariableInfo = pseudocodeVariablesData.getBlockScopeVariableInfo();
final Map> reportedDiagnosticMap = Maps.newHashMap();
PseudocodeTraverserKt.traverse(
pseudocode, TraversalOrder.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, blockScopeVariableInfo);
if (ctxt.variableDescriptor == null) return;
if (instruction instanceof ReadValueInstruction) {
ReadValueInstruction readValueInstruction = (ReadValueInstruction) instruction;
KtElement element = readValueInstruction.getElement();
if (PseudocodeUtil.isThisOrNoDispatchReceiver(readValueInstruction, trace.getBindingContext()) &&
declaredVariables.contains(ctxt.variableDescriptor)) {
checkIsInitialized(ctxt, element, varWithUninitializedErrorGenerated);
}
return;
}
if (!(instruction instanceof WriteValueInstruction)) return;
WriteValueInstruction writeValueInstruction = (WriteValueInstruction) instruction;
KtElement element = writeValueInstruction.getLValue();
if (!(element instanceof KtExpression)) return;
boolean error = checkValReassignment(ctxt, (KtExpression) element, writeValueInstruction,
varWithValReassignErrorGenerated);
if (!error && processClassOrObject) {
error = checkAssignmentBeforeDeclaration(ctxt, (KtExpression) element);
}
if (!error && processClassOrObject) {
checkInitializationForCustomSetter(ctxt, (KtExpression) element);
}
}
}
);
}
private 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 boolean isDefinitelyInitialized(@NotNull PropertyDescriptor propertyDescriptor) {
if (propertyDescriptor.isLateInit()) return true;
if (trace.get(BACKING_FIELD_REQUIRED, propertyDescriptor) == Boolean.TRUE) return false;
PsiElement property = DescriptorToSourceUtils.descriptorToDeclaration(propertyDescriptor);
if (property instanceof KtProperty && ((KtProperty) property).hasDelegate()) return false;
return true;
}
private void checkIsInitialized(
@NotNull VariableInitContext ctxt,
@NotNull KtElement element,
@NotNull Collection varWithUninitializedErrorGenerated
) {
if (!(element instanceof KtSimpleNameExpression)) return;
boolean isDefinitelyInitialized = ctxt.exitInitState.definitelyInitialized();
VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
if (!isDefinitelyInitialized && variableDescriptor instanceof PropertyDescriptor) {
isDefinitelyInitialized = isDefinitelyInitialized((PropertyDescriptor) variableDescriptor);
}
if (!isDefinitelyInitialized && !varWithUninitializedErrorGenerated.contains(variableDescriptor)) {
if (!(variableDescriptor instanceof PropertyDescriptor)) {
varWithUninitializedErrorGenerated.add(variableDescriptor);
}
if (variableDescriptor instanceof ValueParameterDescriptor) {
report(Errors.UNINITIALIZED_PARAMETER.on((KtSimpleNameExpression) element,
(ValueParameterDescriptor) variableDescriptor), ctxt);
}
else {
report(Errors.UNINITIALIZED_VARIABLE.on((KtSimpleNameExpression) element, variableDescriptor), ctxt);
}
}
}
// Should return KtDeclarationWithBody or KtClassOrObject
@Nullable
public static KtDeclaration getElementParentDeclaration(@NotNull KtElement element) {
//noinspection unchecked
return PsiTreeUtil.getParentOfType(element, KtDeclarationWithBody.class, KtClassOrObject.class);
}
@Nullable
private DeclarationDescriptor getDeclarationDescriptor(@Nullable KtDeclaration declaration) {
DeclarationDescriptor descriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, declaration);
if (descriptor instanceof ClassDescriptor) {
// For a class primary constructor, we cannot directly get ConstructorDescriptor by KtClassInitializer,
// so we have to do additional conversion: KtClassInitializer -> KtClassOrObject -> ClassDescriptor -> ConstructorDescriptor
ClassDescriptor classDescriptor = (ClassDescriptor) descriptor;
return classDescriptor.getUnsubstitutedPrimaryConstructor();
}
else {
return descriptor;
}
}
private boolean isCapturedWrite(
@NotNull VariableDescriptor variableDescriptor,
@NotNull WriteValueInstruction writeValueInstruction
) {
DeclarationDescriptor containingDeclarationDescriptor = variableDescriptor.getContainingDeclaration();
// Do not consider member / top-level properties
if (containingDeclarationDescriptor instanceof ClassOrPackageFragmentDescriptor) return false;
KtDeclaration parentDeclaration = getElementParentDeclaration(writeValueInstruction.getElement());
while (true) {
DeclarationDescriptor parentDescriptor = getDeclarationDescriptor(parentDeclaration);
if (containingDeclarationDescriptor.equals(parentDescriptor)) {
return false;
}
else if (parentDeclaration instanceof KtObjectDeclaration) {
// anonymous object counts here the same as its owner
parentDeclaration = getElementParentDeclaration(parentDeclaration);
}
else {
return true;
}
}
}
private boolean checkValReassignment(
@NotNull VariableInitContext ctxt,
@NotNull KtExpression expression,
@NotNull WriteValueInstruction writeValueInstruction,
@NotNull Collection varWithValReassignErrorGenerated
) {
VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
PropertyDescriptor propertyDescriptor = SyntheticFieldDescriptorKt.getReferencedProperty(variableDescriptor);
if (KtPsiUtil.isBackingFieldReference(variableDescriptor) && propertyDescriptor != null) {
KtPropertyAccessor accessor = PsiTreeUtil.getParentOfType(expression, KtPropertyAccessor.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 mayBeInitializedNotHere = ctxt.enterInitState.mayBeInitialized();
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();
ResolvedCall resolvedCall = CallUtilKt.getResolvedCall(expression, trace.getBindingContext());
ReceiverValue receiverValue = null;
if (resolvedCall != null) {
receiverValue = ResolvedCallUtilKt.getDispatchReceiverWithSmartCast(resolvedCall);
}
if (Visibilities.isVisible(receiverValue, variableDescriptor, descriptor) && setterDescriptor != null
&& !Visibilities.isVisible(receiverValue, setterDescriptor, descriptor)) {
report(Errors.INVISIBLE_SETTER.on(expression, variableDescriptor, setterDescriptor.getVisibility(),
setterDescriptor), ctxt);
return true;
}
}
boolean isThisOrNoDispatchReceiver =
PseudocodeUtil.isThisOrNoDispatchReceiver(writeValueInstruction, trace.getBindingContext());
boolean captured = isCapturedWrite(variableDescriptor, writeValueInstruction);
if ((mayBeInitializedNotHere || !hasBackingField || !isThisOrNoDispatchReceiver || captured) && !variableDescriptor.isVar()) {
boolean hasReassignMethodReturningUnit = false;
KtSimpleNameExpression operationReference = null;
PsiElement parent = expression.getParent();
if (parent instanceof KtBinaryExpression) {
operationReference = ((KtBinaryExpression) parent).getOperationReference();
}
else if (parent instanceof KtUnaryExpression) {
operationReference = ((KtUnaryExpression) parent).getOperationReference();
}
if (operationReference != null) {
DeclarationDescriptor descriptor = trace.get(BindingContext.REFERENCE_TARGET, operationReference);
if (descriptor instanceof FunctionDescriptor) {
if (KotlinBuiltIns.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.isUnit(((FunctionDescriptor) referenceDescriptor).getReturnType())) {
hasReassignMethodReturningUnit = true;
}
}
}
}
}
if (!hasReassignMethodReturningUnit) {
if (!isThisOrNoDispatchReceiver || !varWithValReassignErrorGenerated.contains(variableDescriptor)) {
if (captured && !mayBeInitializedNotHere && hasBackingField && isThisOrNoDispatchReceiver) {
report(Errors.CAPTURED_VAL_INITIALIZATION.on(expression, variableDescriptor), ctxt);
}
else {
report(Errors.VAL_REASSIGNMENT.on(expression, variableDescriptor), ctxt);
}
}
if (isThisOrNoDispatchReceiver) {
// try to get rid of repeating VAL_REASSIGNMENT diagnostic only for vars with no receiver
// or when receiver is this
varWithValReassignErrorGenerated.add(variableDescriptor);
}
return true;
}
}
return false;
}
private boolean checkAssignmentBeforeDeclaration(@NotNull VariableInitContext ctxt, @NotNull KtExpression expression) {
if (!ctxt.enterInitState.isDeclared() && !ctxt.exitInitState.isDeclared()
&& !ctxt.enterInitState.mayBeInitialized() && ctxt.exitInitState.mayBeInitialized()) {
report(Errors.INITIALIZATION_BEFORE_DECLARATION.on(expression, ctxt.variableDescriptor), ctxt);
return true;
}
return false;
}
private boolean checkInitializationForCustomSetter(@NotNull VariableInitContext ctxt, @NotNull KtExpression expression) {
VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
if (!(variableDescriptor instanceof PropertyDescriptor)
|| ctxt.enterInitState.mayBeInitialized()
|| !ctxt.exitInitState.mayBeInitialized()
|| !variableDescriptor.isVar()
|| !trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor)
) {
return false;
}
PsiElement property = DescriptorToSourceUtils.descriptorToDeclaration(variableDescriptor);
assert property instanceof KtProperty;
KtPropertyAccessor setter = ((KtProperty) property).getSetter();
if (((PropertyDescriptor) variableDescriptor).getModality() == Modality.FINAL && (setter == null || !setter.hasBody())) {
return false;
}
KtExpression variable = expression;
if (expression instanceof KtDotQualifiedExpression) {
if (((KtDotQualifiedExpression) expression).getReceiverExpression() instanceof KtThisExpression) {
variable = ((KtDotQualifiedExpression) expression).getSelectorExpression();
}
}
if (variable instanceof KtSimpleNameExpression) {
trace.record(IS_UNINITIALIZED, (PropertyDescriptor) variableDescriptor);
return true;
}
return false;
}
private void recordInitializedVariables(
@NotNull Pseudocode pseudocode,
@NotNull Map> initializersMap
) {
Edges initializers = initializersMap.get(pseudocode.getExitInstruction());
if (initializers == null) return;
Set declaredVariables = getPseudocodeVariablesData().getDeclaredVariables(pseudocode, false);
for (VariableDescriptor variable : declaredVariables) {
if (variable instanceof PropertyDescriptor) {
VariableControlFlowState variableControlFlowState = initializers.getIncoming().get(variable);
if (variableControlFlowState != null && variableControlFlowState.definitelyInitialized()) continue;
trace.record(BindingContext.IS_UNINITIALIZED, (PropertyDescriptor) variable);
}
}
}
////////////////////////////////////////////////////////////////////////////////
// "Unused variable" & "unused value" analyses
private 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)
|| !ExpressionTypingUtils.isLocal(variableDescriptor.getContainingDeclaration(), variableDescriptor)) {
return;
}
VariableUseState variableUseState = in.get(variableDescriptor);
if (instruction instanceof WriteValueInstruction) {
if (trace.get(CAPTURED_IN_CLOSURE, variableDescriptor) != null) return;
KtElement element = ((WriteValueInstruction) instruction).getElement();
if (variableUseState != READ) {
if (element instanceof KtBinaryExpression &&
((KtBinaryExpression) element).getOperationToken() == KtTokens.EQ) {
KtExpression right = ((KtBinaryExpression) element).getRight();
if (right != null) {
report(Errors.UNUSED_VALUE.on((KtBinaryExpression) element, right, variableDescriptor), ctxt);
}
}
else if (element instanceof KtPostfixExpression) {
IElementType operationToken =
((KtPostfixExpression) element).getOperationReference().getReferencedNameElementType();
if (operationToken == KtTokens.PLUSPLUS || operationToken == KtTokens.MINUSMINUS) {
report(Errors.UNUSED_CHANGED_VALUE.on(element, element), ctxt);
}
}
}
}
else if (instruction instanceof VariableDeclarationInstruction) {
KtDeclaration element = ((VariableDeclarationInstruction) instruction).getVariableDeclarationElement();
if (!(element instanceof KtNamedDeclaration)) return;
PsiElement nameIdentifier = ((KtNamedDeclaration) element).getNameIdentifier();
if (nameIdentifier == null) return;
if (!VariableUseState.isUsed(variableUseState)) {
if (KtPsiUtil.isVariableNotParameterDeclaration(element)) {
report(Errors.UNUSED_VARIABLE.on((KtNamedDeclaration) element, variableDescriptor), ctxt);
}
else if (element instanceof KtParameter) {
PsiElement owner = element.getParent().getParent();
if (owner instanceof KtPrimaryConstructor) {
if (!((KtParameter) element).hasValOrVar()) {
KtClassOrObject containingClass = ((KtPrimaryConstructor) owner).getContainingClassOrObject();
DeclarationDescriptor containingClassDescriptor = trace.get(
BindingContext.DECLARATION_TO_DESCRIPTOR, containingClass
);
if (!DescriptorUtils.isAnnotationClass(containingClassDescriptor)) {
report(Errors.UNUSED_PARAMETER.on((KtParameter) element, variableDescriptor), ctxt);
}
}
}
else if (owner instanceof KtFunction) {
MainFunctionDetector mainFunctionDetector = new MainFunctionDetector(trace.getBindingContext());
boolean isMain = (owner instanceof KtNamedFunction) && mainFunctionDetector.isMain((KtNamedFunction) owner);
if (owner instanceof KtFunctionLiteral) return;
DeclarationDescriptor descriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, owner);
assert descriptor instanceof FunctionDescriptor : owner.getText();
FunctionDescriptor functionDescriptor = (FunctionDescriptor) descriptor;
String functionName = functionDescriptor.getName().asString();
KtFunction function = (KtFunction) owner;
if (isMain
|| ModalityKt.isOverridableOrOverrides(functionDescriptor)
|| function.hasModifier(KtTokens.OVERRIDE_KEYWORD)
|| "getValue".equals(functionName) || "setValue".equals(functionName)
|| "propertyDelegated".equals(functionName)
) {
return;
}
report(Errors.UNUSED_PARAMETER.on((KtParameter) element, variableDescriptor), ctxt);
}
}
}
else if (variableUseState == ONLY_WRITTEN_NEVER_READ && KtPsiUtil.isVariableNotParameterDeclaration(element)) {
report(Errors.ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE.on((KtNamedDeclaration) element, variableDescriptor), ctxt);
}
else if (variableUseState == WRITTEN_AFTER_READ && element instanceof KtVariableDeclaration) {
if (element instanceof KtProperty) {
KtExpression initializer = ((KtProperty) element).getInitializer();
if (initializer != null) {
report(Errors.VARIABLE_WITH_REDUNDANT_INITIALIZER.on(initializer, variableDescriptor), ctxt);
}
}
else if (element instanceof KtDestructuringDeclarationEntry) {
report(VARIABLE_WITH_REDUNDANT_INITIALIZER.on(element, variableDescriptor), ctxt);
}
}
}
}
};
PseudocodeTraverserKt.traverse(pseudocode, TraversalOrder.BACKWARD, variableStatusData, variableStatusAnalyzeStrategy);
}
////////////////////////////////////////////////////////////////////////////////
// "Unused expressions" in block
private void markUnusedExpressions() {
final Map> reportedDiagnosticMap = Maps.newHashMap();
PseudocodeTraverserKt.traverse(
pseudocode, TraversalOrder.FORWARD, new ControlFlowInformationProvider.FunctionVoid1() {
@Override
public void execute(@NotNull Instruction instruction) {
if (!(instruction instanceof KtElementInstruction)) return;
KtElement element = ((KtElementInstruction)instruction).getElement();
if (!(element instanceof KtExpression)) return;
if (BindingContextUtilsKt.isUsedAsStatement((KtExpression) element, trace.getBindingContext())
&& PseudocodeUtilsKt.getSideEffectFree(instruction)) {
VariableContext ctxt = new VariableContext(instruction, reportedDiagnosticMap);
report(
element instanceof KtLambdaExpression
? Errors.UNUSED_LAMBDA_EXPRESSION.on((KtLambdaExpression) element)
: Errors.UNUSED_EXPRESSION.on(element),
ctxt
);
}
}
}
);
}
////////////////////////////////////////////////////////////////////////////////
// Statements
private void markStatements() {
PseudocodeTraverserKt.traverse(
pseudocode, TraversalOrder.FORWARD, new ControlFlowInformationProvider.FunctionVoid1() {
@Override
public void execute(@NotNull Instruction instruction) {
PseudoValue value = instruction instanceof InstructionWithValue
? ((InstructionWithValue) instruction).getOutputValue()
: null;
Pseudocode pseudocode = instruction.getOwner();
List usages = pseudocode.getUsages(value);
boolean isUsedAsExpression = !usages.isEmpty();
boolean isUsedAsResultOfLambda = isUsedAsResultOfLambda(usages);
for (KtElement element : pseudocode.getValueElements(value)) {
trace.record(BindingContext.USED_AS_EXPRESSION, element, isUsedAsExpression);
trace.record(BindingContext.USED_AS_RESULT_OF_LAMBDA, element, isUsedAsResultOfLambda);
}
}
}
);
}
private static boolean isUsedAsResultOfLambda(List usages) {
for (Instruction usage : usages) {
if (usage instanceof ReturnValueInstruction) {
KtElement returnElement = ((ReturnValueInstruction) usage).getElement();
PsiElement parentElement = returnElement.getParent();
if (!(returnElement instanceof KtReturnExpression ||
parentElement instanceof KtDeclaration && !(parentElement instanceof KtFunctionLiteral))) {
return true;
}
}
}
return false;
}
private void checkIfExpressions() {
PseudocodeTraverserKt.traverse(
pseudocode, TraversalOrder.FORWARD, new ControlFlowInformationProvider.FunctionVoid1() {
@Override
public void execute(@NotNull Instruction instruction) {
PseudoValue value = instruction instanceof InstructionWithValue
? ((InstructionWithValue) instruction).getOutputValue()
: null;
for (KtElement element : instruction.getOwner().getValueElements(value)) {
if (!(element instanceof KtIfExpression)) continue;
KtIfExpression ifExpression = (KtIfExpression) element;
if (BindingContextUtilsKt.isUsedAsExpression(ifExpression, trace.getBindingContext())) {
KtExpression thenExpression = ifExpression.getThen();
KtExpression elseExpression = ifExpression.getElse();
if (thenExpression == null || elseExpression == null) {
trace.report(INVALID_IF_AS_EXPRESSION.on(ifExpression));
}
else {
checkImplicitCastOnConditionalExpression(ifExpression);
}
}
}
}
}
);
}
private static List collectResultingExpressionsOfConditionalExpression(KtExpression expression) {
List leafBranches = new ArrayList();
collectResultingExpressionsOfConditionalExpressionRec(expression, leafBranches);
return leafBranches;
}
private static void collectResultingExpressionsOfConditionalExpressionRec(
@Nullable KtExpression expression,
@NotNull List resultingExpressions
) {
if (expression instanceof KtIfExpression) {
KtIfExpression ifExpression = (KtIfExpression) expression;
collectResultingExpressionsOfConditionalExpressionRec(ifExpression.getThen(), resultingExpressions);
collectResultingExpressionsOfConditionalExpressionRec(ifExpression.getElse(), resultingExpressions);
}
else if (expression instanceof KtWhenExpression) {
KtWhenExpression whenExpression = (KtWhenExpression) expression;
for (KtWhenEntry whenEntry : whenExpression.getEntries()) {
collectResultingExpressionsOfConditionalExpressionRec(whenEntry.getExpression(), resultingExpressions);
}
}
else if (expression != null){
KtExpression resultingExpression = getResultingExpression(expression);
if (resultingExpression instanceof KtIfExpression || resultingExpression instanceof KtWhenExpression) {
collectResultingExpressionsOfConditionalExpressionRec(resultingExpression, resultingExpressions);
}
else {
resultingExpressions.add(resultingExpression);
}
}
}
private void checkImplicitCastOnConditionalExpression(@NotNull KtExpression expression) {
Collection branchExpressions = collectResultingExpressionsOfConditionalExpression(expression);
KotlinType expectedExpressionType = trace.get(EXPECTED_EXPRESSION_TYPE, expression);
if (expectedExpressionType != null && expectedExpressionType != DONT_CARE) return;
KotlinType expressionType = trace.getType(expression);
if (expressionType == null) {
return;
}
if (KotlinBuiltIns.isAnyOrNullableAny(expressionType)) {
boolean isUsedAsResultOfLambda = BindingContextUtilsKt.isUsedAsResultOfLambda(expression, trace.getBindingContext());
for (KtExpression branchExpression : branchExpressions) {
if (branchExpression == null) continue;
KotlinType branchType = trace.getType(branchExpression);
if (branchType == null
|| KotlinBuiltIns.isAnyOrNullableAny(branchType)
|| (isUsedAsResultOfLambda && KotlinBuiltIns.isUnitOrNullableUnit(branchType))) {
return;
}
}
for (KtExpression branchExpression : branchExpressions) {
if (branchExpression == null) continue;
KotlinType branchType = trace.getType(branchExpression);
if (branchType == null) continue;
if (KotlinBuiltIns.isNothing(branchType)) continue;
trace.report(IMPLICIT_CAST_TO_ANY.on(getResultingExpression(branchExpression), branchType, expressionType));
}
}
}
private static @NotNull KtExpression getResultingExpression(@NotNull KtExpression expression) {
KtExpression finger = expression;
while (true) {
KtExpression deparenthesized = KtPsiUtil.deparenthesize(finger);
deparenthesized = KtPsiUtil.getExpressionOrLastStatementInBlock(deparenthesized);
if (deparenthesized == null || deparenthesized == finger) break;
finger = deparenthesized;
}
return finger;
}
private void checkWhenExpressions() {
final Map> initializers = pseudocodeVariablesData.getVariableInitializers();
PseudocodeTraverserKt.traverse(
pseudocode, TraversalOrder.FORWARD, new ControlFlowInformationProvider.FunctionVoid1() {
@Override
public void execute(@NotNull Instruction instruction) {
if (instruction instanceof MagicInstruction) {
MagicInstruction magicInstruction = (MagicInstruction) instruction;
if (magicInstruction.getKind() == MagicKind.EXHAUSTIVE_WHEN_ELSE) {
Instruction next = magicInstruction.getNext();
if (next instanceof MergeInstruction) {
MergeInstruction mergeInstruction = (MergeInstruction) next;
if (initializers.containsKey(mergeInstruction) && initializers.containsKey(magicInstruction)) {
InitControlFlowInfo mergeInfo = initializers.get(mergeInstruction).getIncoming();
InitControlFlowInfo magicInfo = initializers.get(magicInstruction).getOutgoing();
if (mergeInstruction.getElement() instanceof KtWhenExpression &&
magicInfo.checkDefiniteInitializationInWhen(mergeInfo)) {
trace.record(IMPLICIT_EXHAUSTIVE_WHEN, (KtWhenExpression) mergeInstruction.getElement());
}
}
}
}
}
PseudoValue value = instruction instanceof InstructionWithValue
? ((InstructionWithValue) instruction).getOutputValue()
: null;
for (KtElement element : instruction.getOwner().getValueElements(value)) {
if (!(element instanceof KtWhenExpression)) continue;
KtWhenExpression whenExpression = (KtWhenExpression) element;
if (BindingContextUtilsKt.isUsedAsExpression(whenExpression, trace.getBindingContext())) {
checkImplicitCastOnConditionalExpression(whenExpression);
}
if (whenExpression.getElseExpression() != null) continue;
BindingContext context = trace.getBindingContext();
List necessaryCases = WhenChecker.getNecessaryCases(whenExpression, context);
if (!necessaryCases.isEmpty()) {
trace.report(NO_ELSE_IN_WHEN.on(whenExpression, necessaryCases));
}
else if (whenExpression.getSubjectExpression() != null) {
ClassDescriptor enumClassDescriptor = WhenChecker.getClassDescriptorOfTypeIfEnum(
trace.getType(whenExpression.getSubjectExpression()));
if (enumClassDescriptor != null) {
List missingCases = WhenChecker.getEnumMissingCases(
whenExpression, context, enumClassDescriptor
);
if (!missingCases.isEmpty()) {
trace.report(NON_EXHAUSTIVE_WHEN.on(whenExpression, missingCases));
}
}
}
}
}
}
);
}
////////////////////////////////////////////////////////////////////////////////
// Tail calls
private void markTailCalls() {
final DeclarationDescriptor subroutineDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, subroutine);
if (!(subroutineDescriptor instanceof FunctionDescriptor)) return;
if (!((FunctionDescriptor) subroutineDescriptor).isTailrec()) return;
// finally blocks are copied which leads to multiple diagnostics reported on one instruction
class KindAndCall {
TailRecursionKind kind;
private final ResolvedCall call;
KindAndCall(TailRecursionKind kind, ResolvedCall call) {
this.kind = kind;
this.call = call;
}
}
final Map calls = new HashMap();
PseudocodeTraverserKt.traverse(
pseudocode,
TraversalOrder.FORWARD,
new FunctionVoid1() {
@Override
public void execute(@NotNull Instruction instruction) {
if (!(instruction instanceof CallInstruction)) return;
CallInstruction callInstruction = (CallInstruction) instruction;
ResolvedCall resolvedCall = CallUtilKt.getResolvedCall(callInstruction.getElement(), trace.getBindingContext());
if (resolvedCall == null) return;
// is this a recursive call?
CallableDescriptor functionDescriptor = resolvedCall.getResultingDescriptor();
if (!functionDescriptor.getOriginal().equals(subroutineDescriptor)) return;
// Overridden functions using default arguments at tail call are not included: KT-4285
if (resolvedCall.getCall().getValueArguments().size() != functionDescriptor.getValueParameters().size() &&
!functionDescriptor.getOverriddenDescriptors().isEmpty()) return;
KtElement element = callInstruction.getElement();
//noinspection unchecked
KtExpression parent = PsiTreeUtil.getParentOfType(
element,
KtTryExpression.class, KtFunction.class, KtAnonymousInitializer.class
);
if (parent instanceof KtTryExpression) {
// 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 = PseudocodeTraverserKt.traverseFollowingInstructions(
callInstruction,
new HashSet(),
TraversalOrder.FORWARD,
new TailRecursionDetector(subroutine, callInstruction)
);
// A tail call is not allowed to change dispatch receiver
// class C {
// fun foo(other: C) {
// other.foo(this) // not a tail call
// }
// }
boolean sameDispatchReceiver =
ResolvedCallUtilKt.hasThisOrNoDispatchReceiver(resolvedCall, trace.getBindingContext());
TailRecursionKind kind = isTail && sameDispatchReceiver ? 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()) {
KtElement element = entry.getKey();
KindAndCall kindAndCall = entry.getValue();
switch (kindAndCall.kind) {
case TAIL_CALL:
trace.record(TAIL_RECURSION_CALL, kindAndCall.call.getCall(), 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((KtNamedFunction) subroutine));
}
}
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 VariableControlFlowState enterInitState;
final VariableControlFlowState exitInitState;
private VariableInitContext(
@NotNull Instruction instruction,
@NotNull Map> map,
@NotNull Map in,
@NotNull Map out,
@NotNull BlockScopeVariableInfo blockScopeVariableInfo
) {
super(instruction, map);
enterInitState = initialize(variableDescriptor, blockScopeVariableInfo, in);
exitInitState = initialize(variableDescriptor, blockScopeVariableInfo, out);
}
private VariableControlFlowState initialize(
VariableDescriptor variableDescriptor,
BlockScopeVariableInfo blockScopeVariableInfo,
Map map
) {
if (variableDescriptor == null) return null;
VariableControlFlowState state = map.get(variableDescriptor);
if (state != null) return state;
return PseudocodeVariablesData.getDefaultValueForInitializers(variableDescriptor, instruction, blockScopeVariableInfo);
}
}
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
private abstract static class InstructionDataAnalyzeStrategy implements Function3 {
@Override
public Unit invoke(Instruction instruction, D enterData, D exitData) {
execute(instruction, enterData, exitData);
return Unit.INSTANCE;
}
public abstract void execute(Instruction instruction, D enterData, D exitData);
}
private abstract static class FunctionVoid1 implements Function1 {
@Override
public Unit invoke(P p) {
execute(p);
return Unit.INSTANCE;
}
public abstract void execute(P p);
}
}
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