001 /*
002 * Copyright 2010-2015 JetBrains s.r.o.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017 package org.jetbrains.kotlin.cfg;
018
019 import com.google.common.collect.Lists;
020 import com.google.common.collect.Maps;
021 import com.google.common.collect.Sets;
022 import com.intellij.psi.PsiElement;
023 import com.intellij.psi.tree.IElementType;
024 import com.intellij.psi.util.PsiTreeUtil;
025 import kotlin.Unit;
026 import kotlin.jvm.functions.Function1;
027 import kotlin.jvm.functions.Function3;
028 import org.jetbrains.annotations.NotNull;
029 import org.jetbrains.annotations.Nullable;
030 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
031 import org.jetbrains.kotlin.cfg.PseudocodeVariablesData.VariableControlFlowState;
032 import org.jetbrains.kotlin.cfg.PseudocodeVariablesData.VariableUseState;
033 import org.jetbrains.kotlin.cfg.pseudocode.PseudoValue;
034 import org.jetbrains.kotlin.cfg.pseudocode.Pseudocode;
035 import org.jetbrains.kotlin.cfg.pseudocode.PseudocodeUtil;
036 import org.jetbrains.kotlin.cfg.pseudocode.PseudocodeUtilsKt;
037 import org.jetbrains.kotlin.cfg.pseudocode.instructions.Instruction;
038 import org.jetbrains.kotlin.cfg.pseudocode.instructions.InstructionVisitor;
039 import org.jetbrains.kotlin.cfg.pseudocode.instructions.JetElementInstruction;
040 import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.*;
041 import org.jetbrains.kotlin.cfg.pseudocode.instructions.jumps.*;
042 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.LocalFunctionDeclarationInstruction;
043 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.MarkInstruction;
044 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.SubroutineExitInstruction;
045 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.VariableDeclarationInstruction;
046 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.Edges;
047 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.PseudocodeTraverserKt;
048 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder;
049 import org.jetbrains.kotlin.descriptors.*;
050 import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptorKt;
051 import org.jetbrains.kotlin.diagnostics.Diagnostic;
052 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory;
053 import org.jetbrains.kotlin.diagnostics.Errors;
054 import org.jetbrains.kotlin.idea.MainFunctionDetector;
055 import org.jetbrains.kotlin.lexer.KtTokens;
056 import org.jetbrains.kotlin.psi.*;
057 import org.jetbrains.kotlin.resolve.*;
058 import org.jetbrains.kotlin.resolve.bindingContextUtil.BindingContextUtilsKt;
059 import org.jetbrains.kotlin.resolve.calls.callUtil.CallUtilKt;
060 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall;
061 import org.jetbrains.kotlin.resolve.calls.resolvedCallUtil.ResolvedCallUtilKt;
062 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue;
063 import org.jetbrains.kotlin.types.KotlinType;
064 import org.jetbrains.kotlin.types.expressions.ExpressionTypingUtils;
065
066 import java.util.*;
067
068 import static org.jetbrains.kotlin.cfg.PseudocodeVariablesData.VariableUseState.*;
069 import static org.jetbrains.kotlin.cfg.TailRecursionKind.*;
070 import static org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder.FORWARD;
071 import static org.jetbrains.kotlin.diagnostics.Errors.*;
072 import static org.jetbrains.kotlin.diagnostics.Errors.UNREACHABLE_CODE;
073 import static org.jetbrains.kotlin.resolve.BindingContext.*;
074 import static org.jetbrains.kotlin.types.TypeUtils.NO_EXPECTED_TYPE;
075 import static org.jetbrains.kotlin.types.TypeUtils.noExpectedType;
076
077 public class JetFlowInformationProvider {
078
079 private final KtElement subroutine;
080 private final Pseudocode pseudocode;
081 private final BindingTrace trace;
082 private PseudocodeVariablesData pseudocodeVariablesData;
083
084 private JetFlowInformationProvider(
085 @NotNull KtElement declaration,
086 @NotNull BindingTrace trace,
087 @NotNull Pseudocode pseudocode
088 ) {
089 this.subroutine = declaration;
090 this.trace = trace;
091 this.pseudocode = pseudocode;
092 }
093
094 public JetFlowInformationProvider(
095 @NotNull KtElement declaration,
096 @NotNull BindingTrace trace
097 ) {
098 this(declaration, trace, new JetControlFlowProcessor(trace).generatePseudocode(declaration));
099 }
100
101 public PseudocodeVariablesData getPseudocodeVariablesData() {
102 if (pseudocodeVariablesData == null) {
103 pseudocodeVariablesData = new PseudocodeVariablesData(pseudocode, trace.getBindingContext());
104 }
105 return pseudocodeVariablesData;
106 }
107
108 public void checkForLocalClassOrObjectMode() {
109 // Local classes and objects are analyzed twice: when TopDownAnalyzer processes it and as a part of its container.
110 // Almost all checks can be done when the container is analyzed
111 // except recording initialized variables (this information is needed for DeclarationChecker).
112 recordInitializedVariables();
113 }
114
115 public void checkDeclaration() {
116
117 recordInitializedVariables();
118
119 checkLocalFunctions();
120
121 markUninitializedVariables();
122
123 markUnusedVariables();
124
125 markStatements();
126
127 markUnusedExpressions();
128
129 markWhenWithoutElse();
130 }
131
132 public void checkFunction(@Nullable KotlinType expectedReturnType) {
133 UnreachableCode unreachableCode = collectUnreachableCode();
134 reportUnreachableCode(unreachableCode);
135
136 if (subroutine instanceof KtFunctionLiteral) return;
137
138 checkDefiniteReturn(expectedReturnType != null ? expectedReturnType : NO_EXPECTED_TYPE, unreachableCode);
139
140 markTailCalls();
141 }
142
143 private void collectReturnExpressions(@NotNull final Collection<KtElement> returnedExpressions) {
144 final Set<Instruction> instructions = Sets.newHashSet(pseudocode.getInstructions());
145 SubroutineExitInstruction exitInstruction = pseudocode.getExitInstruction();
146 for (Instruction previousInstruction : exitInstruction.getPreviousInstructions()) {
147 previousInstruction.accept(new InstructionVisitor() {
148 @Override
149 public void visitReturnValue(@NotNull ReturnValueInstruction instruction) {
150 if (instructions.contains(instruction)) { //exclude non-local return expressions
151 returnedExpressions.add(instruction.getElement());
152 }
153 }
154
155 @Override
156 public void visitReturnNoValue(@NotNull ReturnNoValueInstruction instruction) {
157 if (instructions.contains(instruction)) {
158 returnedExpressions.add(instruction.getElement());
159 }
160 }
161
162
163 @Override
164 public void visitJump(@NotNull AbstractJumpInstruction instruction) {
165 // Nothing
166 }
167
168 @Override
169 public void visitUnconditionalJump(@NotNull UnconditionalJumpInstruction instruction) {
170 redirectToPrevInstructions(instruction);
171 }
172
173 private void redirectToPrevInstructions(Instruction instruction) {
174 for (Instruction previousInstruction : instruction.getPreviousInstructions()) {
175 previousInstruction.accept(this);
176 }
177 }
178
179 @Override
180 public void visitNondeterministicJump(@NotNull NondeterministicJumpInstruction instruction) {
181 redirectToPrevInstructions(instruction);
182 }
183
184 @Override
185 public void visitMarkInstruction(@NotNull MarkInstruction instruction) {
186 redirectToPrevInstructions(instruction);
187 }
188
189 @Override
190 public void visitInstruction(@NotNull Instruction instruction) {
191 if (instruction instanceof JetElementInstruction) {
192 JetElementInstruction elementInstruction = (JetElementInstruction) instruction;
193 returnedExpressions.add(elementInstruction.getElement());
194 }
195 else {
196 throw new IllegalStateException(instruction + " precedes the exit point");
197 }
198 }
199 });
200 }
201 }
202
203 private void checkLocalFunctions() {
204 for (LocalFunctionDeclarationInstruction localDeclarationInstruction : pseudocode.getLocalDeclarations()) {
205 KtElement element = localDeclarationInstruction.getElement();
206 if (element instanceof KtDeclarationWithBody) {
207 KtDeclarationWithBody localDeclaration = (KtDeclarationWithBody) element;
208
209 CallableDescriptor functionDescriptor =
210 (CallableDescriptor) trace.getBindingContext().get(BindingContext.DECLARATION_TO_DESCRIPTOR, localDeclaration);
211 KotlinType expectedType = functionDescriptor != null ? functionDescriptor.getReturnType() : null;
212
213 JetFlowInformationProvider providerForLocalDeclaration =
214 new JetFlowInformationProvider(localDeclaration, trace, localDeclarationInstruction.getBody());
215
216 providerForLocalDeclaration.checkFunction(expectedType);
217 }
218 }
219 }
220
221 public void checkDefiniteReturn(final @NotNull KotlinType expectedReturnType, @NotNull final UnreachableCode unreachableCode) {
222 assert subroutine instanceof KtDeclarationWithBody;
223 KtDeclarationWithBody function = (KtDeclarationWithBody) subroutine;
224
225 if (!function.hasBody()) return;
226
227 List<KtElement> returnedExpressions = Lists.newArrayList();
228 collectReturnExpressions(returnedExpressions);
229
230 final boolean blockBody = function.hasBlockBody();
231
232 final boolean[] noReturnError = new boolean[] { false };
233 for (KtElement returnedExpression : returnedExpressions) {
234 returnedExpression.accept(new KtVisitorVoid() {
235 @Override
236 public void visitReturnExpression(@NotNull KtReturnExpression expression) {
237 if (!blockBody) {
238 trace.report(RETURN_IN_FUNCTION_WITH_EXPRESSION_BODY.on(expression));
239 }
240 }
241
242 @Override
243 public void visitKtElement(@NotNull KtElement element) {
244 if (!(element instanceof KtExpression || element instanceof KtWhenCondition)) return;
245
246 if (blockBody && !noExpectedType(expectedReturnType)
247 && !KotlinBuiltIns.isUnit(expectedReturnType)
248 && !unreachableCode.getElements().contains(element)) {
249 noReturnError[0] = true;
250 }
251 }
252 });
253 }
254 if (noReturnError[0]) {
255 trace.report(NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY.on(function));
256 }
257 }
258
259 private void reportUnreachableCode(@NotNull UnreachableCode unreachableCode) {
260 for (KtElement element : unreachableCode.getElements()) {
261 trace.report(UNREACHABLE_CODE.on(element, unreachableCode.getUnreachableTextRanges(element)));
262 trace.record(BindingContext.UNREACHABLE_CODE, element, true);
263 }
264 }
265
266 @NotNull
267 private UnreachableCode collectUnreachableCode() {
268 Set<KtElement> reachableElements = Sets.newHashSet();
269 Set<KtElement> unreachableElements = Sets.newHashSet();
270 for (Instruction instruction : pseudocode.getInstructionsIncludingDeadCode()) {
271 if (!(instruction instanceof JetElementInstruction)
272 || instruction instanceof LoadUnitValueInstruction
273 || instruction instanceof MergeInstruction
274 || (instruction instanceof MagicInstruction && ((MagicInstruction) instruction).getSynthetic())) continue;
275
276 KtElement element = ((JetElementInstruction) instruction).getElement();
277
278 if (instruction instanceof JumpInstruction) {
279 boolean isJumpElement = element instanceof KtBreakExpression
280 || element instanceof KtContinueExpression
281 || element instanceof KtReturnExpression
282 || element instanceof KtThrowExpression;
283 if (!isJumpElement) continue;
284 }
285
286 if (instruction.getDead()) {
287 unreachableElements.add(element);
288 }
289 else {
290 reachableElements.add(element);
291 }
292 }
293 return new UnreachableCodeImpl(reachableElements, unreachableElements);
294 }
295
296 ////////////////////////////////////////////////////////////////////////////////
297 // Uninitialized variables analysis
298
299 public void markUninitializedVariables() {
300 final Collection<VariableDescriptor> varWithUninitializedErrorGenerated = Sets.newHashSet();
301 final Collection<VariableDescriptor> varWithValReassignErrorGenerated = Sets.newHashSet();
302 final boolean processClassOrObject = subroutine instanceof KtClassOrObject;
303
304 PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
305 Map<Instruction, Edges<Map<VariableDescriptor, VariableControlFlowState>>> initializers =
306 pseudocodeVariablesData.getVariableInitializers();
307 final Set<VariableDescriptor> declaredVariables = pseudocodeVariablesData.getDeclaredVariables(pseudocode, true);
308 final LexicalScopeVariableInfo lexicalScopeVariableInfo = pseudocodeVariablesData.getLexicalScopeVariableInfo();
309
310 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap = Maps.newHashMap();
311
312 PseudocodeTraverserKt.traverse(
313 pseudocode, FORWARD, initializers,
314 new InstructionDataAnalyzeStrategy<Map<VariableDescriptor, VariableControlFlowState>>() {
315 @Override
316 public void execute(
317 @NotNull Instruction instruction,
318 @Nullable Map<VariableDescriptor, VariableControlFlowState> in,
319 @Nullable Map<VariableDescriptor, VariableControlFlowState> out
320 ) {
321 assert in != null && out != null;
322 VariableInitContext ctxt =
323 new VariableInitContext(instruction, reportedDiagnosticMap, in, out, lexicalScopeVariableInfo);
324 if (ctxt.variableDescriptor == null) return;
325 if (instruction instanceof ReadValueInstruction) {
326 ReadValueInstruction readValueInstruction = (ReadValueInstruction) instruction;
327 KtElement element = readValueInstruction.getElement();
328 if (PseudocodeUtil.isThisOrNoDispatchReceiver(readValueInstruction, trace.getBindingContext()) &&
329 declaredVariables.contains(ctxt.variableDescriptor)) {
330 checkIsInitialized(ctxt, element, varWithUninitializedErrorGenerated);
331 }
332 return;
333 }
334 if (!(instruction instanceof WriteValueInstruction)) return;
335 WriteValueInstruction writeValueInstruction = (WriteValueInstruction) instruction;
336 KtElement element = writeValueInstruction.getLValue();
337 if (!(element instanceof KtExpression)) return;
338 boolean error = checkValReassignment(ctxt, (KtExpression) element, writeValueInstruction,
339 varWithValReassignErrorGenerated);
340 if (!error && processClassOrObject) {
341 error = checkAssignmentBeforeDeclaration(ctxt, (KtExpression) element);
342 }
343 if (!error && processClassOrObject) {
344 checkInitializationForCustomSetter(ctxt, (KtExpression) element);
345 }
346 }
347 }
348 );
349 }
350
351 public void recordInitializedVariables() {
352 PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
353 Pseudocode pseudocode = pseudocodeVariablesData.getPseudocode();
354 Map<Instruction, Edges<Map<VariableDescriptor, VariableControlFlowState>>> initializers =
355 pseudocodeVariablesData.getVariableInitializers();
356 recordInitializedVariables(pseudocode, initializers);
357 for (LocalFunctionDeclarationInstruction instruction : pseudocode.getLocalDeclarations()) {
358 recordInitializedVariables(instruction.getBody(), initializers);
359 }
360 }
361
362 private void checkIsInitialized(
363 @NotNull VariableInitContext ctxt,
364 @NotNull KtElement element,
365 @NotNull Collection<VariableDescriptor> varWithUninitializedErrorGenerated
366 ) {
367 if (!(element instanceof KtSimpleNameExpression)) return;
368
369
370 boolean isDefinitelyInitialized = ctxt.exitInitState.definitelyInitialized();
371 VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
372 if (variableDescriptor instanceof PropertyDescriptor) {
373 PropertyDescriptor propertyDescriptor = (PropertyDescriptor) variableDescriptor;
374 if (propertyDescriptor.isLateInit() || !trace.get(BindingContext.BACKING_FIELD_REQUIRED, propertyDescriptor)) {
375 isDefinitelyInitialized = true;
376 }
377 }
378 if (!isDefinitelyInitialized && !varWithUninitializedErrorGenerated.contains(variableDescriptor)) {
379 if (!(variableDescriptor instanceof PropertyDescriptor)) {
380 varWithUninitializedErrorGenerated.add(variableDescriptor);
381 }
382 if (variableDescriptor instanceof ValueParameterDescriptor) {
383 report(Errors.UNINITIALIZED_PARAMETER.on((KtSimpleNameExpression) element,
384 (ValueParameterDescriptor) variableDescriptor), ctxt);
385 }
386 else {
387 report(Errors.UNINITIALIZED_VARIABLE.on((KtSimpleNameExpression) element, variableDescriptor), ctxt);
388 }
389 }
390 }
391
392 private boolean checkValReassignment(
393 @NotNull VariableInitContext ctxt,
394 @NotNull KtExpression expression,
395 @NotNull WriteValueInstruction writeValueInstruction,
396 @NotNull Collection<VariableDescriptor> varWithValReassignErrorGenerated
397 ) {
398 VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
399 PropertyDescriptor propertyDescriptor = SyntheticFieldDescriptorKt.getReferencedProperty(variableDescriptor);
400 if (KtPsiUtil.isBackingFieldReference(variableDescriptor) && propertyDescriptor != null) {
401 KtPropertyAccessor accessor = PsiTreeUtil.getParentOfType(expression, KtPropertyAccessor.class);
402 if (accessor != null) {
403 DeclarationDescriptor accessorDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, accessor);
404 if (propertyDescriptor.getGetter() == accessorDescriptor) {
405 //val can be reassigned through backing field inside its own getter
406 return false;
407 }
408 }
409 }
410
411 boolean mayBeInitializedNotHere = ctxt.enterInitState.mayBeInitialized();
412 boolean hasBackingField = true;
413 if (variableDescriptor instanceof PropertyDescriptor) {
414 hasBackingField = trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor);
415 }
416 if (variableDescriptor.isVar() && variableDescriptor instanceof PropertyDescriptor) {
417 DeclarationDescriptor descriptor = BindingContextUtils.getEnclosingDescriptor(trace.getBindingContext(), expression);
418 PropertySetterDescriptor setterDescriptor = ((PropertyDescriptor) variableDescriptor).getSetter();
419
420 ResolvedCall<? extends CallableDescriptor> resolvedCall = CallUtilKt.getResolvedCall(expression, trace.getBindingContext());
421 ReceiverValue receiverValue = ReceiverValue.IRRELEVANT_RECEIVER;
422 if (resolvedCall != null) {
423 receiverValue = ExpressionTypingUtils
424 .normalizeReceiverValueForVisibility(resolvedCall.getDispatchReceiver(), trace.getBindingContext());
425
426 }
427 if (Visibilities.isVisible(receiverValue, variableDescriptor, descriptor) && setterDescriptor != null
428 && !Visibilities.isVisible(receiverValue, setterDescriptor, descriptor)) {
429 report(Errors.INVISIBLE_SETTER.on(expression, variableDescriptor, setterDescriptor.getVisibility(),
430 setterDescriptor), ctxt);
431 return true;
432 }
433 }
434 boolean isThisOrNoDispatchReceiver =
435 PseudocodeUtil.isThisOrNoDispatchReceiver(writeValueInstruction, trace.getBindingContext());
436 if ((mayBeInitializedNotHere || !hasBackingField || !isThisOrNoDispatchReceiver) && !variableDescriptor.isVar()) {
437 boolean hasReassignMethodReturningUnit = false;
438 KtSimpleNameExpression operationReference = null;
439 PsiElement parent = expression.getParent();
440 if (parent instanceof KtBinaryExpression) {
441 operationReference = ((KtBinaryExpression) parent).getOperationReference();
442 }
443 else if (parent instanceof KtUnaryExpression) {
444 operationReference = ((KtUnaryExpression) parent).getOperationReference();
445 }
446 if (operationReference != null) {
447 DeclarationDescriptor descriptor = trace.get(BindingContext.REFERENCE_TARGET, operationReference);
448 if (descriptor instanceof FunctionDescriptor) {
449 if (KotlinBuiltIns.isUnit(((FunctionDescriptor) descriptor).getReturnType())) {
450 hasReassignMethodReturningUnit = true;
451 }
452 }
453 if (descriptor == null) {
454 Collection<? extends DeclarationDescriptor> descriptors =
455 trace.get(BindingContext.AMBIGUOUS_REFERENCE_TARGET, operationReference);
456 if (descriptors != null) {
457 for (DeclarationDescriptor referenceDescriptor : descriptors) {
458 if (KotlinBuiltIns.isUnit(((FunctionDescriptor) referenceDescriptor).getReturnType())) {
459 hasReassignMethodReturningUnit = true;
460 }
461 }
462 }
463 }
464 }
465 if (!hasReassignMethodReturningUnit) {
466 if (!isThisOrNoDispatchReceiver || !varWithValReassignErrorGenerated.contains(variableDescriptor)) {
467 report(Errors.VAL_REASSIGNMENT.on(expression, variableDescriptor), ctxt);
468 }
469 if (isThisOrNoDispatchReceiver) {
470 // try to get rid of repeating VAL_REASSIGNMENT diagnostic only for vars with no receiver
471 // or when receiver is this
472 varWithValReassignErrorGenerated.add(variableDescriptor);
473 }
474 return true;
475 }
476 }
477 return false;
478 }
479
480 private boolean checkAssignmentBeforeDeclaration(@NotNull VariableInitContext ctxt, @NotNull KtExpression expression) {
481 if (!ctxt.enterInitState.isDeclared && !ctxt.exitInitState.isDeclared
482 && !ctxt.enterInitState.mayBeInitialized() && ctxt.exitInitState.mayBeInitialized()) {
483 report(Errors.INITIALIZATION_BEFORE_DECLARATION.on(expression, ctxt.variableDescriptor), ctxt);
484 return true;
485 }
486 return false;
487 }
488
489 private boolean checkInitializationForCustomSetter(@NotNull VariableInitContext ctxt, @NotNull KtExpression expression) {
490 VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
491 if (!(variableDescriptor instanceof PropertyDescriptor)
492 || ctxt.enterInitState.mayBeInitialized()
493 || !ctxt.exitInitState.mayBeInitialized()
494 || !variableDescriptor.isVar()
495 || !trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor)
496 ) {
497 return false;
498 }
499
500 PsiElement property = DescriptorToSourceUtils.descriptorToDeclaration(variableDescriptor);
501 assert property instanceof KtProperty;
502 KtPropertyAccessor setter = ((KtProperty) property).getSetter();
503 if (((PropertyDescriptor) variableDescriptor).getModality() == Modality.FINAL && (setter == null || !setter.hasBody())) {
504 return false;
505 }
506
507 KtExpression variable = expression;
508 if (expression instanceof KtDotQualifiedExpression) {
509 if (((KtDotQualifiedExpression) expression).getReceiverExpression() instanceof KtThisExpression) {
510 variable = ((KtDotQualifiedExpression) expression).getSelectorExpression();
511 }
512 }
513 if (variable instanceof KtSimpleNameExpression) {
514 trace.record(IS_UNINITIALIZED, (PropertyDescriptor) variableDescriptor);
515 return true;
516 }
517 return false;
518 }
519
520 private void recordInitializedVariables(
521 @NotNull Pseudocode pseudocode,
522 @NotNull Map<Instruction, Edges<Map<VariableDescriptor, VariableControlFlowState>>> initializersMap
523 ) {
524 Edges<Map<VariableDescriptor, VariableControlFlowState>> initializers = initializersMap.get(pseudocode.getExitInstruction());
525 if (initializers == null) return;
526 Set<VariableDescriptor> declaredVariables = getPseudocodeVariablesData().getDeclaredVariables(pseudocode, false);
527 for (VariableDescriptor variable : declaredVariables) {
528 if (variable instanceof PropertyDescriptor) {
529 VariableControlFlowState variableControlFlowState = initializers.getIncoming().get(variable);
530 if (variableControlFlowState != null && variableControlFlowState.definitelyInitialized()) continue;
531 trace.record(BindingContext.IS_UNINITIALIZED, (PropertyDescriptor) variable);
532 }
533 }
534 }
535
536 ////////////////////////////////////////////////////////////////////////////////
537 // "Unused variable" & "unused value" analyses
538
539 public void markUnusedVariables() {
540 final PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
541 Map<Instruction, Edges<Map<VariableDescriptor, VariableUseState>>> variableStatusData =
542 pseudocodeVariablesData.getVariableUseStatusData();
543 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap = Maps.newHashMap();
544 InstructionDataAnalyzeStrategy<Map<VariableDescriptor, VariableUseState>> variableStatusAnalyzeStrategy =
545 new InstructionDataAnalyzeStrategy<Map<VariableDescriptor, VariableUseState>>() {
546 @Override
547 public void execute(
548 @NotNull Instruction instruction,
549 @Nullable Map<VariableDescriptor, VariableUseState> in,
550 @Nullable Map<VariableDescriptor, VariableUseState> out
551 ) {
552
553 assert in != null && out != null;
554 VariableContext ctxt = new VariableUseContext(instruction, reportedDiagnosticMap, in, out);
555 Set<VariableDescriptor> declaredVariables =
556 pseudocodeVariablesData.getDeclaredVariables(instruction.getOwner(), false);
557 VariableDescriptor variableDescriptor = PseudocodeUtil.extractVariableDescriptorIfAny(
558 instruction, false, trace.getBindingContext());
559 if (variableDescriptor == null || !declaredVariables.contains(variableDescriptor)
560 || !ExpressionTypingUtils.isLocal(variableDescriptor.getContainingDeclaration(), variableDescriptor)) {
561 return;
562 }
563 PseudocodeVariablesData.VariableUseState variableUseState = in.get(variableDescriptor);
564 if (instruction instanceof WriteValueInstruction) {
565 if (trace.get(CAPTURED_IN_CLOSURE, variableDescriptor) != null) return;
566 KtElement element = ((WriteValueInstruction) instruction).getElement();
567 if (variableUseState != READ) {
568 if (element instanceof KtBinaryExpression &&
569 ((KtBinaryExpression) element).getOperationToken() == KtTokens.EQ) {
570 KtExpression right = ((KtBinaryExpression) element).getRight();
571 if (right != null) {
572 report(Errors.UNUSED_VALUE.on((KtBinaryExpression) element, right, variableDescriptor), ctxt);
573 }
574 }
575 else if (element instanceof KtPostfixExpression) {
576 IElementType operationToken =
577 ((KtPostfixExpression) element).getOperationReference().getReferencedNameElementType();
578 if (operationToken == KtTokens.PLUSPLUS || operationToken == KtTokens.MINUSMINUS) {
579 report(Errors.UNUSED_CHANGED_VALUE.on(element, element), ctxt);
580 }
581 }
582 }
583 }
584 else if (instruction instanceof VariableDeclarationInstruction) {
585 KtDeclaration element = ((VariableDeclarationInstruction) instruction).getVariableDeclarationElement();
586 if (!(element instanceof KtNamedDeclaration)) return;
587 PsiElement nameIdentifier = ((KtNamedDeclaration) element).getNameIdentifier();
588 if (nameIdentifier == null) return;
589 if (!VariableUseState.isUsed(variableUseState)) {
590 if (KtPsiUtil.isVariableNotParameterDeclaration(element)) {
591 report(Errors.UNUSED_VARIABLE.on((KtNamedDeclaration) element, variableDescriptor), ctxt);
592 }
593 else if (element instanceof KtParameter) {
594 PsiElement owner = element.getParent().getParent();
595 if (owner instanceof KtPrimaryConstructor) {
596 if (!((KtParameter) element).hasValOrVar()) {
597 KtClassOrObject containingClass = ((KtPrimaryConstructor) owner).getContainingClassOrObject();
598 DeclarationDescriptor containingClassDescriptor = trace.get(
599 BindingContext.DECLARATION_TO_DESCRIPTOR, containingClass
600 );
601 if (!DescriptorUtils.isAnnotationClass(containingClassDescriptor)) {
602 report(Errors.UNUSED_PARAMETER.on((KtParameter) element, variableDescriptor), ctxt);
603 }
604 }
605 }
606 else if (owner instanceof KtFunction) {
607 MainFunctionDetector mainFunctionDetector = new MainFunctionDetector(trace.getBindingContext());
608 boolean isMain = (owner instanceof KtNamedFunction) && mainFunctionDetector.isMain((KtNamedFunction) owner);
609 if (owner instanceof KtFunctionLiteral) return;
610 DeclarationDescriptor descriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, owner);
611 assert descriptor instanceof FunctionDescriptor : owner.getText();
612 FunctionDescriptor functionDescriptor = (FunctionDescriptor) descriptor;
613 String functionName = functionDescriptor.getName().asString();
614 if (isMain
615 || functionDescriptor.getModality().isOverridable()
616 || !functionDescriptor.getOverriddenDescriptors().isEmpty()
617 || "getValue".equals(functionName) || "setValue".equals(functionName)
618 || "propertyDelegated".equals(functionName)
619 ) {
620 return;
621 }
622 report(Errors.UNUSED_PARAMETER.on((KtParameter) element, variableDescriptor), ctxt);
623 }
624 }
625 }
626 else if (variableUseState == ONLY_WRITTEN_NEVER_READ && KtPsiUtil.isVariableNotParameterDeclaration(element)) {
627 report(Errors.ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE.on((KtNamedDeclaration) element, variableDescriptor), ctxt);
628 }
629 else if (variableUseState == WRITTEN_AFTER_READ && element instanceof KtVariableDeclaration) {
630 if (element instanceof KtProperty) {
631 KtExpression initializer = ((KtProperty) element).getInitializer();
632 if (initializer != null) {
633 report(Errors.VARIABLE_WITH_REDUNDANT_INITIALIZER.on(initializer, variableDescriptor), ctxt);
634 }
635 }
636 else if (element instanceof KtMultiDeclarationEntry) {
637 report(VARIABLE_WITH_REDUNDANT_INITIALIZER.on(element, variableDescriptor), ctxt);
638 }
639 }
640 }
641 }
642 };
643 PseudocodeTraverserKt.traverse(pseudocode, TraversalOrder.BACKWARD, variableStatusData, variableStatusAnalyzeStrategy);
644 }
645
646 ////////////////////////////////////////////////////////////////////////////////
647 // "Unused expressions" in block
648
649 public void markUnusedExpressions() {
650 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap = Maps.newHashMap();
651 PseudocodeTraverserKt.traverse(
652 pseudocode, FORWARD, new JetFlowInformationProvider.FunctionVoid1<Instruction>() {
653 @Override
654 public void execute(@NotNull Instruction instruction) {
655 if (!(instruction instanceof JetElementInstruction)) return;
656
657 KtElement element = ((JetElementInstruction)instruction).getElement();
658 if (!(element instanceof KtExpression)) return;
659
660 if (BindingContextUtilsKt.isUsedAsStatement((KtExpression) element, trace.getBindingContext())
661 && PseudocodeUtilsKt.getSideEffectFree(instruction)) {
662 VariableContext ctxt = new VariableContext(instruction, reportedDiagnosticMap);
663 report(
664 element instanceof KtFunctionLiteralExpression
665 ? Errors.UNUSED_FUNCTION_LITERAL.on((KtFunctionLiteralExpression) element)
666 : Errors.UNUSED_EXPRESSION.on(element),
667 ctxt
668 );
669 }
670 }
671 }
672 );
673 }
674
675 ////////////////////////////////////////////////////////////////////////////////
676 // Statements
677
678 public void markStatements() {
679 PseudocodeTraverserKt.traverse(
680 pseudocode, FORWARD, new JetFlowInformationProvider.FunctionVoid1<Instruction>() {
681 @Override
682 public void execute(@NotNull Instruction instruction) {
683 PseudoValue value = instruction instanceof InstructionWithValue
684 ? ((InstructionWithValue) instruction).getOutputValue()
685 : null;
686 Pseudocode pseudocode = instruction.getOwner();
687 boolean isUsedAsExpression = !pseudocode.getUsages(value).isEmpty();
688 for (KtElement element : pseudocode.getValueElements(value)) {
689 trace.record(BindingContext.USED_AS_EXPRESSION, element, isUsedAsExpression);
690 }
691 }
692 }
693 );
694 }
695
696 public void markWhenWithoutElse() {
697 PseudocodeTraverserKt.traverse(
698 pseudocode, FORWARD, new JetFlowInformationProvider.FunctionVoid1<Instruction>() {
699 @Override
700 public void execute(@NotNull Instruction instruction) {
701 PseudoValue value = instruction instanceof InstructionWithValue
702 ? ((InstructionWithValue) instruction).getOutputValue()
703 : null;
704 for (KtElement element : instruction.getOwner().getValueElements(value)) {
705 if (!(element instanceof KtWhenExpression)) continue;
706 KtWhenExpression whenExpression = (KtWhenExpression) element;
707 if (whenExpression.getElseExpression() != null) continue;
708
709 if (WhenChecker.mustHaveElse(whenExpression, trace)) {
710 trace.report(NO_ELSE_IN_WHEN.on(whenExpression));
711 }
712 else if (whenExpression.getSubjectExpression() != null) {
713 ClassDescriptor enumClassDescriptor = WhenChecker.getClassDescriptorOfTypeIfEnum(
714 trace.getType(whenExpression.getSubjectExpression()));
715 if (enumClassDescriptor != null
716 && !WhenChecker.isWhenOnEnumExhaustive(whenExpression, trace, enumClassDescriptor)) {
717 trace.report(NON_EXHAUSTIVE_WHEN.on(whenExpression));
718 }
719 }
720 }
721 }
722 }
723 );
724 }
725
726 ////////////////////////////////////////////////////////////////////////////////
727 // Tail calls
728
729 public void markTailCalls() {
730 final DeclarationDescriptor subroutineDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, subroutine);
731 if (!(subroutineDescriptor instanceof FunctionDescriptor)) return;
732 if (!((FunctionDescriptor) subroutineDescriptor).isTailrec()) return;
733
734 // finally blocks are copied which leads to multiple diagnostics reported on one instruction
735 class KindAndCall {
736 TailRecursionKind kind;
737 ResolvedCall<?> call;
738
739 KindAndCall(TailRecursionKind kind, ResolvedCall<?> call) {
740 this.kind = kind;
741 this.call = call;
742 }
743 }
744 final Map<KtElement, KindAndCall> calls = new HashMap<KtElement, KindAndCall>();
745 PseudocodeTraverserKt.traverse(
746 pseudocode,
747 FORWARD,
748 new FunctionVoid1<Instruction>() {
749 public void execute(@NotNull Instruction instruction) {
750 if (!(instruction instanceof CallInstruction)) return;
751 CallInstruction callInstruction = (CallInstruction) instruction;
752
753 ResolvedCall<?> resolvedCall = CallUtilKt.getResolvedCall(callInstruction.getElement(), trace.getBindingContext());
754 if (resolvedCall == null) return;
755
756 // is this a recursive call?
757 CallableDescriptor functionDescriptor = resolvedCall.getResultingDescriptor();
758 if (!functionDescriptor.getOriginal().equals(subroutineDescriptor)) return;
759
760 KtElement element = callInstruction.getElement();
761 //noinspection unchecked
762 KtExpression parent = PsiTreeUtil.getParentOfType(
763 element,
764 KtTryExpression.class, KtFunction.class, KtClassInitializer.class
765 );
766
767 if (parent instanceof KtTryExpression) {
768 // We do not support tail calls Collections.singletonMap() try-catch-finally, for simplicity of the mental model
769 // very few cases there would be real tail-calls, and it's often not so easy for the user to see why
770 calls.put(element, new KindAndCall(IN_TRY, resolvedCall));
771 return;
772 }
773
774 boolean isTail = PseudocodeTraverserKt.traverseFollowingInstructions(
775 callInstruction,
776 new HashSet<Instruction>(),
777 FORWARD,
778 new TailRecursionDetector(subroutine, callInstruction)
779 );
780
781 // A tail call is not allowed to change dispatch receiver
782 // class C {
783 // fun foo(other: C) {
784 // other.foo(this) // not a tail call
785 // }
786 // }
787 boolean sameDispatchReceiver =
788 ResolvedCallUtilKt.hasThisOrNoDispatchReceiver(resolvedCall, trace.getBindingContext());
789
790 TailRecursionKind kind = isTail && sameDispatchReceiver ? TAIL_CALL : NON_TAIL;
791
792 KindAndCall kindAndCall = calls.get(element);
793 calls.put(element,
794 new KindAndCall(
795 combineKinds(kind, kindAndCall == null ? null : kindAndCall.kind),
796 resolvedCall
797 )
798 );
799 }
800 }
801 );
802 boolean hasTailCalls = false;
803 for (Map.Entry<KtElement, KindAndCall> entry : calls.entrySet()) {
804 KtElement element = entry.getKey();
805 KindAndCall kindAndCall = entry.getValue();
806 switch (kindAndCall.kind) {
807 case TAIL_CALL:
808 trace.record(TAIL_RECURSION_CALL, kindAndCall.call, TailRecursionKind.TAIL_CALL);
809 hasTailCalls = true;
810 break;
811 case IN_TRY:
812 trace.report(Errors.TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED.on(element));
813 break;
814 case NON_TAIL:
815 trace.report(Errors.NON_TAIL_RECURSIVE_CALL.on(element));
816 break;
817 }
818 }
819
820 if (!hasTailCalls) {
821 trace.report(Errors.NO_TAIL_CALLS_FOUND.on((KtNamedFunction) subroutine));
822 }
823 }
824
825 private static TailRecursionKind combineKinds(TailRecursionKind kind, @Nullable TailRecursionKind existingKind) {
826 TailRecursionKind resultingKind;
827 if (existingKind == null || existingKind == kind) {
828 resultingKind = kind;
829 }
830 else {
831 if (check(kind, existingKind, IN_TRY, TAIL_CALL)) {
832 resultingKind = IN_TRY;
833 }
834 else if (check(kind, existingKind, IN_TRY, NON_TAIL)) {
835 resultingKind = IN_TRY;
836 }
837 else {
838 // TAIL_CALL, NON_TAIL
839 resultingKind = NON_TAIL;
840 }
841 }
842 return resultingKind;
843 }
844
845 private static boolean check(Object a, Object b, Object x, Object y) {
846 return (a == x && b == y) || (a == y && b == x);
847 }
848
849 ////////////////////////////////////////////////////////////////////////////////
850 // Utility classes and methods
851
852 /**
853 * The method provides reporting of the same diagnostic only once for copied instructions
854 * (depends on whether it should be reported for all or only for one of the copies)
855 */
856 private void report(
857 @NotNull Diagnostic diagnostic,
858 @NotNull VariableContext ctxt
859 ) {
860 Instruction instruction = ctxt.instruction;
861 if (instruction.getCopies().isEmpty()) {
862 trace.report(diagnostic);
863 return;
864 }
865 Map<Instruction, DiagnosticFactory<?>> previouslyReported = ctxt.reportedDiagnosticMap;
866 previouslyReported.put(instruction, diagnostic.getFactory());
867
868 boolean alreadyReported = false;
869 boolean sameErrorForAllCopies = true;
870 for (Instruction copy : instruction.getCopies()) {
871 DiagnosticFactory<?> previouslyReportedErrorFactory = previouslyReported.get(copy);
872 if (previouslyReportedErrorFactory != null) {
873 alreadyReported = true;
874 }
875
876 if (previouslyReportedErrorFactory != diagnostic.getFactory()) {
877 sameErrorForAllCopies = false;
878 }
879 }
880
881 if (mustBeReportedOnAllCopies(diagnostic.getFactory())) {
882 if (sameErrorForAllCopies) {
883 trace.report(diagnostic);
884 }
885 }
886 else {
887 //only one reporting required
888 if (!alreadyReported) {
889 trace.report(diagnostic);
890 }
891 }
892 }
893
894 private static boolean mustBeReportedOnAllCopies(@NotNull DiagnosticFactory<?> diagnosticFactory) {
895 return diagnosticFactory == UNUSED_VARIABLE
896 || diagnosticFactory == UNUSED_PARAMETER
897 || diagnosticFactory == UNUSED_CHANGED_VALUE;
898 }
899
900
901 private class VariableContext {
902 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap;
903 final Instruction instruction;
904 final VariableDescriptor variableDescriptor;
905
906 private VariableContext(
907 @NotNull Instruction instruction,
908 @NotNull Map<Instruction, DiagnosticFactory<?>> map
909 ) {
910 this.instruction = instruction;
911 reportedDiagnosticMap = map;
912 variableDescriptor = PseudocodeUtil.extractVariableDescriptorIfAny(instruction, true, trace.getBindingContext());
913 }
914 }
915
916 private class VariableInitContext extends VariableContext {
917 final VariableControlFlowState enterInitState;
918 final VariableControlFlowState exitInitState;
919
920 private VariableInitContext(
921 @NotNull Instruction instruction,
922 @NotNull Map<Instruction, DiagnosticFactory<?>> map,
923 @NotNull Map<VariableDescriptor, VariableControlFlowState> in,
924 @NotNull Map<VariableDescriptor, VariableControlFlowState> out,
925 @NotNull LexicalScopeVariableInfo lexicalScopeVariableInfo
926 ) {
927 super(instruction, map);
928 enterInitState = initialize(variableDescriptor, lexicalScopeVariableInfo, in);
929 exitInitState = initialize(variableDescriptor, lexicalScopeVariableInfo, out);
930 }
931
932 private VariableControlFlowState initialize(
933 VariableDescriptor variableDescriptor,
934 LexicalScopeVariableInfo lexicalScopeVariableInfo,
935 Map<VariableDescriptor, VariableControlFlowState> map
936 ) {
937 if (variableDescriptor == null) return null;
938 VariableControlFlowState state = map.get(variableDescriptor);
939 if (state != null) return state;
940 return PseudocodeVariablesData.getDefaultValueForInitializers(variableDescriptor, instruction, lexicalScopeVariableInfo);
941 }
942 }
943
944 private class VariableUseContext extends VariableContext {
945 final VariableUseState enterUseState;
946 final VariableUseState exitUseState;
947
948
949 private VariableUseContext(
950 @NotNull Instruction instruction,
951 @NotNull Map<Instruction, DiagnosticFactory<?>> map,
952 @NotNull Map<VariableDescriptor, VariableUseState> in,
953 @NotNull Map<VariableDescriptor, VariableUseState> out
954 ) {
955 super(instruction, map);
956 enterUseState = variableDescriptor != null ? in.get(variableDescriptor) : null;
957 exitUseState = variableDescriptor != null ? out.get(variableDescriptor) : null;
958 }
959 }
960
961 //TODO after KT-4621 rewrite to Kotlin
962 public abstract static class InstructionDataAnalyzeStrategy<D> implements Function3<Instruction, D, D, Unit> {
963 @Override
964 public Unit invoke(Instruction instruction, D enterData, D exitData) {
965 execute(instruction, enterData, exitData);
966 return Unit.INSTANCE$;
967 }
968
969 public abstract void execute(Instruction instruction, D enterData, D exitData);
970 }
971
972 public abstract static class FunctionVoid1<P> implements Function1<P, Unit> {
973 @Override
974 public Unit invoke(P p) {
975 execute(p);
976 return Unit.INSTANCE$;
977 }
978
979 public abstract void execute(P p);
980 }
981 }