1 //===- ExprEngineCXX.cpp - ExprEngine support for C++ -----------*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file defines the C++ expression evaluation engine.
11 //===----------------------------------------------------------------------===//
13 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
14 #include "clang/Analysis/ConstructionContext.h"
15 #include "clang/AST/DeclCXX.h"
16 #include "clang/AST/StmtCXX.h"
17 #include "clang/AST/ParentMap.h"
18 #include "clang/Basic/PrettyStackTrace.h"
19 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
21 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
23 using namespace clang;
26 void ExprEngine::CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
28 ExplodedNodeSet &Dst) {
29 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
30 const Expr *tempExpr = ME->getSubExpr()->IgnoreParens();
31 ProgramStateRef state = Pred->getState();
32 const LocationContext *LCtx = Pred->getLocationContext();
34 state = createTemporaryRegionIfNeeded(state, LCtx, tempExpr, ME);
35 Bldr.generateNode(ME, Pred, state);
38 // FIXME: This is the sort of code that should eventually live in a Core
39 // checker rather than as a special case in ExprEngine.
40 void ExprEngine::performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred,
41 const CallEvent &Call) {
43 bool AlwaysReturnsLValue;
44 const CXXRecordDecl *ThisRD = nullptr;
45 if (const CXXConstructorCall *Ctor = dyn_cast<CXXConstructorCall>(&Call)) {
46 assert(Ctor->getDecl()->isTrivial());
47 assert(Ctor->getDecl()->isCopyOrMoveConstructor());
48 ThisVal = Ctor->getCXXThisVal();
49 ThisRD = Ctor->getDecl()->getParent();
50 AlwaysReturnsLValue = false;
52 assert(cast<CXXMethodDecl>(Call.getDecl())->isTrivial());
53 assert(cast<CXXMethodDecl>(Call.getDecl())->getOverloadedOperator() ==
55 ThisVal = cast<CXXInstanceCall>(Call).getCXXThisVal();
56 ThisRD = cast<CXXMethodDecl>(Call.getDecl())->getParent();
57 AlwaysReturnsLValue = true;
61 if (ThisRD->isEmpty()) {
62 // Do nothing for empty classes. Otherwise it'd retrieve an UnknownVal
63 // and bind it and RegionStore would think that the actual value
64 // in this region at this offset is unknown.
68 const LocationContext *LCtx = Pred->getLocationContext();
73 SVal V = Call.getArgSVal(0);
75 // If the value being copied is not unknown, load from its location to get
76 // an aggregate rvalue.
77 if (Optional<Loc> L = V.getAs<Loc>())
78 V = Pred->getState()->getSVal(*L);
80 assert(V.isUnknownOrUndef());
82 const Expr *CallExpr = Call.getOriginExpr();
83 evalBind(Dst, CallExpr, Pred, ThisVal, V, true);
85 PostStmt PS(CallExpr, LCtx);
86 for (ExplodedNodeSet::iterator I = Dst.begin(), E = Dst.end();
88 ProgramStateRef State = (*I)->getState();
89 if (AlwaysReturnsLValue)
90 State = State->BindExpr(CallExpr, LCtx, ThisVal);
92 State = bindReturnValue(Call, LCtx, State);
93 Bldr.generateNode(PS, State, *I);
98 SVal ExprEngine::makeZeroElementRegion(ProgramStateRef State, SVal LValue,
99 QualType &Ty, bool &IsArray) {
100 SValBuilder &SVB = State->getStateManager().getSValBuilder();
101 ASTContext &Ctx = SVB.getContext();
103 while (const ArrayType *AT = Ctx.getAsArrayType(Ty)) {
104 Ty = AT->getElementType();
105 LValue = State->getLValue(Ty, SVB.makeZeroArrayIndex(), LValue);
112 std::pair<ProgramStateRef, SVal> ExprEngine::prepareForObjectConstruction(
113 const Expr *E, ProgramStateRef State, const LocationContext *LCtx,
114 const ConstructionContext *CC, EvalCallOptions &CallOpts) {
115 SValBuilder &SVB = getSValBuilder();
116 MemRegionManager &MRMgr = SVB.getRegionManager();
117 ASTContext &ACtx = SVB.getContext();
119 // See if we're constructing an existing region by looking at the
120 // current construction context.
122 switch (CC->getKind()) {
123 case ConstructionContext::CXX17ElidedCopyVariableKind:
124 case ConstructionContext::SimpleVariableKind: {
125 const auto *DSCC = cast<VariableConstructionContext>(CC);
126 const auto *DS = DSCC->getDeclStmt();
127 const auto *Var = cast<VarDecl>(DS->getSingleDecl());
128 SVal LValue = State->getLValue(Var, LCtx);
129 QualType Ty = Var->getType();
131 makeZeroElementRegion(State, LValue, Ty, CallOpts.IsArrayCtorOrDtor);
133 addObjectUnderConstruction(State, DSCC->getDeclStmt(), LCtx, LValue);
134 return std::make_pair(State, LValue);
136 case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind:
137 case ConstructionContext::SimpleConstructorInitializerKind: {
138 const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);
139 const auto *Init = ICC->getCXXCtorInitializer();
140 assert(Init->isAnyMemberInitializer());
141 const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
143 SVB.getCXXThis(CurCtor, LCtx->getStackFrame());
144 SVal ThisVal = State->getSVal(ThisPtr);
146 const ValueDecl *Field;
148 if (Init->isIndirectMemberInitializer()) {
149 Field = Init->getIndirectMember();
150 FieldVal = State->getLValue(Init->getIndirectMember(), ThisVal);
152 Field = Init->getMember();
153 FieldVal = State->getLValue(Init->getMember(), ThisVal);
156 QualType Ty = Field->getType();
157 FieldVal = makeZeroElementRegion(State, FieldVal, Ty,
158 CallOpts.IsArrayCtorOrDtor);
159 State = addObjectUnderConstruction(State, Init, LCtx, FieldVal);
160 return std::make_pair(State, FieldVal);
162 case ConstructionContext::NewAllocatedObjectKind: {
163 if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
164 const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
165 const auto *NE = NECC->getCXXNewExpr();
166 SVal V = *getObjectUnderConstruction(State, NE, LCtx);
167 if (const SubRegion *MR =
168 dyn_cast_or_null<SubRegion>(V.getAsRegion())) {
170 // TODO: In fact, we need to call the constructor for every
171 // allocated element, not just the first one!
172 CallOpts.IsArrayCtorOrDtor = true;
173 return std::make_pair(
174 State, loc::MemRegionVal(getStoreManager().GetElementZeroRegion(
175 MR, NE->getType()->getPointeeType())));
177 return std::make_pair(State, V);
179 // TODO: Detect when the allocator returns a null pointer.
180 // Constructor shall not be called in this case.
184 case ConstructionContext::SimpleReturnedValueKind:
185 case ConstructionContext::CXX17ElidedCopyReturnedValueKind: {
186 // The temporary is to be managed by the parent stack frame.
187 // So build it in the parent stack frame if we're not in the
188 // top frame of the analysis.
189 const StackFrameContext *SFC = LCtx->getStackFrame();
190 if (const LocationContext *CallerLCtx = SFC->getParent()) {
191 auto RTC = (*SFC->getCallSiteBlock())[SFC->getIndex()]
192 .getAs<CFGCXXRecordTypedCall>();
194 // We were unable to find the correct construction context for the
195 // call in the parent stack frame. This is equivalent to not being
196 // able to find construction context at all.
199 if (isa<BlockInvocationContext>(CallerLCtx)) {
200 // Unwrap block invocation contexts. They're mostly part of
201 // the current stack frame.
202 CallerLCtx = CallerLCtx->getParent();
203 assert(!isa<BlockInvocationContext>(CallerLCtx));
205 return prepareForObjectConstruction(
206 cast<Expr>(SFC->getCallSite()), State, CallerLCtx,
207 RTC->getConstructionContext(), CallOpts);
209 // We are on the top frame of the analysis. We do not know where is the
210 // object returned to. Conjure a symbolic region for the return value.
211 // TODO: We probably need a new MemRegion kind to represent the storage
212 // of that SymbolicRegion, so that we cound produce a fancy symbol
213 // instead of an anonymous conjured symbol.
214 // TODO: Do we need to track the region to avoid having it dead
215 // too early? It does die too early, at least in C++17, but because
216 // putting anything into a SymbolicRegion causes an immediate escape,
217 // it doesn't cause any leak false positives.
218 const auto *RCC = cast<ReturnedValueConstructionContext>(CC);
219 // Make sure that this doesn't coincide with any other symbol
220 // conjured for the returned expression.
221 static const int TopLevelSymRegionTag = 0;
222 const Expr *RetE = RCC->getReturnStmt()->getRetValue();
223 assert(RetE && "Void returns should not have a construction context");
224 QualType ReturnTy = RetE->getType();
225 QualType RegionTy = ACtx.getPointerType(ReturnTy);
226 SVal V = SVB.conjureSymbolVal(&TopLevelSymRegionTag, RetE, SFC,
227 RegionTy, currBldrCtx->blockCount());
228 return std::make_pair(State, V);
230 llvm_unreachable("Unhandled return value construction context!");
232 case ConstructionContext::ElidedTemporaryObjectKind: {
233 assert(AMgr.getAnalyzerOptions().ShouldElideConstructors);
234 const auto *TCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
235 const CXXBindTemporaryExpr *BTE = TCC->getCXXBindTemporaryExpr();
236 const MaterializeTemporaryExpr *MTE = TCC->getMaterializedTemporaryExpr();
237 const CXXConstructExpr *CE = TCC->getConstructorAfterElision();
239 // Support pre-C++17 copy elision. We'll have the elidable copy
240 // constructor in the AST and in the CFG, but we'll skip it
241 // and construct directly into the final object. This call
242 // also sets the CallOpts flags for us.
244 // If the elided copy/move constructor is not supported, there's still
245 // benefit in trying to model the non-elided constructor.
246 // Stash our state before trying to elide, as it'll get overwritten.
247 ProgramStateRef PreElideState = State;
248 EvalCallOptions PreElideCallOpts = CallOpts;
250 std::tie(State, V) = prepareForObjectConstruction(
251 CE, State, LCtx, TCC->getConstructionContextAfterElision(), CallOpts);
253 // FIXME: This definition of "copy elision has not failed" is unreliable.
254 // It doesn't indicate that the constructor will actually be inlined
255 // later; it is still up to evalCall() to decide.
256 if (!CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) {
257 // Remember that we've elided the constructor.
258 State = addObjectUnderConstruction(State, CE, LCtx, V);
260 // Remember that we've elided the destructor.
262 State = elideDestructor(State, BTE, LCtx);
264 // Instead of materialization, shamelessly return
265 // the final object destination.
267 State = addObjectUnderConstruction(State, MTE, LCtx, V);
269 return std::make_pair(State, V);
271 // Copy elision failed. Revert the changes and proceed as if we have
272 // a simple temporary.
273 State = PreElideState;
274 CallOpts = PreElideCallOpts;
278 case ConstructionContext::SimpleTemporaryObjectKind: {
279 const auto *TCC = cast<TemporaryObjectConstructionContext>(CC);
280 const CXXBindTemporaryExpr *BTE = TCC->getCXXBindTemporaryExpr();
281 const MaterializeTemporaryExpr *MTE = TCC->getMaterializedTemporaryExpr();
282 SVal V = UnknownVal();
285 if (const ValueDecl *VD = MTE->getExtendingDecl()) {
286 assert(MTE->getStorageDuration() != SD_FullExpression);
287 if (!VD->getType()->isReferenceType()) {
288 // We're lifetime-extended by a surrounding aggregate.
289 // Automatic destructors aren't quite working in this case
290 // on the CFG side. We should warn the caller about that.
291 // FIXME: Is there a better way to retrieve this information from
292 // the MaterializeTemporaryExpr?
293 CallOpts.IsTemporaryLifetimeExtendedViaAggregate = true;
297 if (MTE->getStorageDuration() == SD_Static ||
298 MTE->getStorageDuration() == SD_Thread)
299 V = loc::MemRegionVal(MRMgr.getCXXStaticTempObjectRegion(E));
303 V = loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));
306 State = addObjectUnderConstruction(State, BTE, LCtx, V);
309 State = addObjectUnderConstruction(State, MTE, LCtx, V);
311 CallOpts.IsTemporaryCtorOrDtor = true;
312 return std::make_pair(State, V);
314 case ConstructionContext::ArgumentKind: {
315 // Arguments are technically temporaries.
316 CallOpts.IsTemporaryCtorOrDtor = true;
318 const auto *ACC = cast<ArgumentConstructionContext>(CC);
319 const Expr *E = ACC->getCallLikeExpr();
320 unsigned Idx = ACC->getIndex();
321 const CXXBindTemporaryExpr *BTE = ACC->getCXXBindTemporaryExpr();
323 CallEventManager &CEMgr = getStateManager().getCallEventManager();
324 SVal V = UnknownVal();
325 auto getArgLoc = [&](CallEventRef<> Caller) -> Optional<SVal> {
326 const LocationContext *FutureSFC =
327 Caller->getCalleeStackFrame(currBldrCtx->blockCount());
328 // Return early if we are unable to reliably foresee
329 // the future stack frame.
333 // This should be equivalent to Caller->getDecl() for now, but
334 // FutureSFC->getDecl() is likely to support better stuff (like
335 // virtual functions) earlier.
336 const Decl *CalleeD = FutureSFC->getDecl();
338 // FIXME: Support for variadic arguments is not implemented here yet.
339 if (CallEvent::isVariadic(CalleeD))
342 // Operator arguments do not correspond to operator parameters
343 // because this-argument is implemented as a normal argument in
344 // operator call expressions but not in operator declarations.
345 const VarRegion *VR = Caller->getParameterLocation(
346 *Caller->getAdjustedParameterIndex(Idx), currBldrCtx->blockCount());
350 return loc::MemRegionVal(VR);
353 if (const auto *CE = dyn_cast<CallExpr>(E)) {
354 CallEventRef<> Caller = CEMgr.getSimpleCall(CE, State, LCtx);
355 if (auto OptV = getArgLoc(Caller))
359 State = addObjectUnderConstruction(State, {CE, Idx}, LCtx, V);
360 } else if (const auto *CCE = dyn_cast<CXXConstructExpr>(E)) {
361 // Don't bother figuring out the target region for the future
362 // constructor because we won't need it.
363 CallEventRef<> Caller =
364 CEMgr.getCXXConstructorCall(CCE, /*Target=*/nullptr, State, LCtx);
365 if (auto OptV = getArgLoc(Caller))
369 State = addObjectUnderConstruction(State, {CCE, Idx}, LCtx, V);
370 } else if (const auto *ME = dyn_cast<ObjCMessageExpr>(E)) {
371 CallEventRef<> Caller = CEMgr.getObjCMethodCall(ME, State, LCtx);
372 if (auto OptV = getArgLoc(Caller))
376 State = addObjectUnderConstruction(State, {ME, Idx}, LCtx, V);
379 assert(!V.isUnknown());
382 State = addObjectUnderConstruction(State, BTE, LCtx, V);
384 return std::make_pair(State, V);
388 // If we couldn't find an existing region to construct into, assume we're
389 // constructing a temporary. Notify the caller of our failure.
390 CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
391 return std::make_pair(
392 State, loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx)));
395 void ExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *CE,
397 ExplodedNodeSet &destNodes) {
398 const LocationContext *LCtx = Pred->getLocationContext();
399 ProgramStateRef State = Pred->getState();
401 SVal Target = UnknownVal();
403 if (Optional<SVal> ElidedTarget =
404 getObjectUnderConstruction(State, CE, LCtx)) {
405 // We've previously modeled an elidable constructor by pretending that it in
406 // fact constructs into the correct target. This constructor can therefore
408 Target = *ElidedTarget;
409 StmtNodeBuilder Bldr(Pred, destNodes, *currBldrCtx);
410 State = finishObjectConstruction(State, CE, LCtx);
411 if (auto L = Target.getAs<Loc>())
412 State = State->BindExpr(CE, LCtx, State->getSVal(*L, CE->getType()));
413 Bldr.generateNode(CE, Pred, State);
417 // FIXME: Handle arrays, which run the same constructor for every element.
418 // For now, we just run the first constructor (which should still invalidate
419 // the entire array).
421 EvalCallOptions CallOpts;
422 auto C = getCurrentCFGElement().getAs<CFGConstructor>();
423 assert(C || getCurrentCFGElement().getAs<CFGStmt>());
424 const ConstructionContext *CC = C ? C->getConstructionContext() : nullptr;
426 switch (CE->getConstructionKind()) {
427 case CXXConstructExpr::CK_Complete: {
428 std::tie(State, Target) =
429 prepareForObjectConstruction(CE, State, LCtx, CC, CallOpts);
432 case CXXConstructExpr::CK_VirtualBase: {
433 // Make sure we are not calling virtual base class initializers twice.
434 // Only the most-derived object should initialize virtual base classes.
435 const auto *OuterCtor = dyn_cast_or_null<CXXConstructExpr>(
436 LCtx->getStackFrame()->getCallSite());
439 OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Complete ||
440 OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Delegating) &&
441 ("This virtual base should have already been initialized by "
442 "the most derived class!"));
446 case CXXConstructExpr::CK_NonVirtualBase:
447 // In C++17, classes with non-virtual bases may be aggregates, so they would
448 // be initialized as aggregates without a constructor call, so we may have
449 // a base class constructed directly into an initializer list without
450 // having the derived-class constructor call on the previous stack frame.
451 // Initializer lists may be nested into more initializer lists that
452 // correspond to surrounding aggregate initializations.
453 // FIXME: For now this code essentially bails out. We need to find the
454 // correct target region and set it.
455 // FIXME: Instead of relying on the ParentMap, we should have the
456 // trigger-statement (InitListExpr in this case) passed down from CFG or
457 // otherwise always available during construction.
458 if (dyn_cast_or_null<InitListExpr>(LCtx->getParentMap().getParent(CE))) {
459 MemRegionManager &MRMgr = getSValBuilder().getRegionManager();
460 Target = loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(CE, LCtx));
461 CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
465 case CXXConstructExpr::CK_Delegating: {
466 const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
467 Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor,
468 LCtx->getStackFrame());
469 SVal ThisVal = State->getSVal(ThisPtr);
471 if (CE->getConstructionKind() == CXXConstructExpr::CK_Delegating) {
474 // Cast to the base type.
476 (CE->getConstructionKind() == CXXConstructExpr::CK_VirtualBase);
477 SVal BaseVal = getStoreManager().evalDerivedToBase(ThisVal, CE->getType(),
485 if (State != Pred->getState()) {
486 static SimpleProgramPointTag T("ExprEngine",
487 "Prepare for object construction");
488 ExplodedNodeSet DstPrepare;
489 StmtNodeBuilder BldrPrepare(Pred, DstPrepare, *currBldrCtx);
490 BldrPrepare.generateNode(CE, Pred, State, &T, ProgramPoint::PreStmtKind);
491 assert(DstPrepare.size() <= 1);
492 if (DstPrepare.size() == 0)
494 Pred = *BldrPrepare.begin();
497 CallEventManager &CEMgr = getStateManager().getCallEventManager();
498 CallEventRef<CXXConstructorCall> Call =
499 CEMgr.getCXXConstructorCall(CE, Target.getAsRegion(), State, LCtx);
501 ExplodedNodeSet DstPreVisit;
502 getCheckerManager().runCheckersForPreStmt(DstPreVisit, Pred, CE, *this);
504 // FIXME: Is it possible and/or useful to do this before PreStmt?
505 ExplodedNodeSet PreInitialized;
507 StmtNodeBuilder Bldr(DstPreVisit, PreInitialized, *currBldrCtx);
508 for (ExplodedNodeSet::iterator I = DstPreVisit.begin(),
509 E = DstPreVisit.end();
511 ProgramStateRef State = (*I)->getState();
512 if (CE->requiresZeroInitialization()) {
513 // FIXME: Once we properly handle constructors in new-expressions, we'll
514 // need to invalidate the region before setting a default value, to make
515 // sure there aren't any lingering bindings around. This probably needs
516 // to happen regardless of whether or not the object is zero-initialized
517 // to handle random fields of a placement-initialized object picking up
518 // old bindings. We might only want to do it when we need to, though.
519 // FIXME: This isn't actually correct for arrays -- we need to zero-
520 // initialize the entire array, not just the first element -- but our
521 // handling of arrays everywhere else is weak as well, so this shouldn't
522 // actually make things worse. Placement new makes this tricky as well,
523 // since it's then possible to be initializing one part of a multi-
524 // dimensional array.
525 State = State->bindDefaultZero(Target, LCtx);
528 Bldr.generateNode(CE, *I, State, /*tag=*/nullptr,
529 ProgramPoint::PreStmtKind);
533 ExplodedNodeSet DstPreCall;
534 getCheckerManager().runCheckersForPreCall(DstPreCall, PreInitialized,
537 ExplodedNodeSet DstEvaluated;
538 StmtNodeBuilder Bldr(DstPreCall, DstEvaluated, *currBldrCtx);
540 if (CE->getConstructor()->isTrivial() &&
541 CE->getConstructor()->isCopyOrMoveConstructor() &&
542 !CallOpts.IsArrayCtorOrDtor) {
543 // FIXME: Handle other kinds of trivial constructors as well.
544 for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
546 performTrivialCopy(Bldr, *I, *Call);
549 for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
551 defaultEvalCall(Bldr, *I, *Call, CallOpts);
554 // If the CFG was constructed without elements for temporary destructors
555 // and the just-called constructor created a temporary object then
556 // stop exploration if the temporary object has a noreturn constructor.
557 // This can lose coverage because the destructor, if it were present
558 // in the CFG, would be called at the end of the full expression or
559 // later (for life-time extended temporaries) -- but avoids infeasible
560 // paths when no-return temporary destructors are used for assertions.
561 const AnalysisDeclContext *ADC = LCtx->getAnalysisDeclContext();
562 if (!ADC->getCFGBuildOptions().AddTemporaryDtors) {
563 const MemRegion *Target = Call->getCXXThisVal().getAsRegion();
564 if (Target && isa<CXXTempObjectRegion>(Target) &&
565 Call->getDecl()->getParent()->isAnyDestructorNoReturn()) {
567 // If we've inlined the constructor, then DstEvaluated would be empty.
568 // In this case we still want a sink, which could be implemented
569 // in processCallExit. But we don't have that implemented at the moment,
570 // so if you hit this assertion, see if you can avoid inlining
571 // the respective constructor when analyzer-config cfg-temporary-dtors
573 // Otherwise there's nothing wrong with inlining such constructor.
574 assert(!DstEvaluated.empty() &&
575 "We should not have inlined this constructor!");
577 for (ExplodedNode *N : DstEvaluated) {
578 Bldr.generateSink(CE, N, N->getState());
581 // There is no need to run the PostCall and PostStmt checker
582 // callbacks because we just generated sinks on all nodes in th
588 ExplodedNodeSet DstPostArgumentCleanup;
589 for (auto I : DstEvaluated)
590 finishArgumentConstruction(DstPostArgumentCleanup, I, *Call);
592 // If there were other constructors called for object-type arguments
593 // of this constructor, clean them up.
594 ExplodedNodeSet DstPostCall;
595 getCheckerManager().runCheckersForPostCall(DstPostCall,
596 DstPostArgumentCleanup,
598 getCheckerManager().runCheckersForPostStmt(destNodes, DstPostCall, CE, *this);
601 void ExprEngine::VisitCXXDestructor(QualType ObjectType,
602 const MemRegion *Dest,
606 ExplodedNodeSet &Dst,
607 EvalCallOptions &CallOpts) {
608 assert(S && "A destructor without a trigger!");
609 const LocationContext *LCtx = Pred->getLocationContext();
610 ProgramStateRef State = Pred->getState();
612 const CXXRecordDecl *RecordDecl = ObjectType->getAsCXXRecordDecl();
613 assert(RecordDecl && "Only CXXRecordDecls should have destructors");
614 const CXXDestructorDecl *DtorDecl = RecordDecl->getDestructor();
615 // FIXME: There should always be a Decl, otherwise the destructor call
616 // shouldn't have been added to the CFG in the first place.
618 // Skip the invalid destructor. We cannot simply return because
619 // it would interrupt the analysis instead.
620 static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");
621 // FIXME: PostImplicitCall with a null decl may crash elsewhere anyway.
622 PostImplicitCall PP(/*Decl=*/nullptr, S->getEndLoc(), LCtx, &T);
623 NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
624 Bldr.generateNode(PP, Pred->getState(), Pred);
629 // We're trying to destroy something that is not a region. This may happen
630 // for a variety of reasons (unknown target region, concrete integer instead
631 // of target region, etc.). The current code makes an attempt to recover.
632 // FIXME: We probably don't really need to recover when we're dealing
633 // with concrete integers specifically.
634 CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
635 if (const Expr *E = dyn_cast_or_null<Expr>(S)) {
636 Dest = MRMgr.getCXXTempObjectRegion(E, Pred->getLocationContext());
638 static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");
639 NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
640 Bldr.generateSink(Pred->getLocation().withTag(&T),
641 Pred->getState(), Pred);
646 CallEventManager &CEMgr = getStateManager().getCallEventManager();
647 CallEventRef<CXXDestructorCall> Call =
648 CEMgr.getCXXDestructorCall(DtorDecl, S, Dest, IsBaseDtor, State, LCtx);
650 PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
651 Call->getSourceRange().getBegin(),
652 "Error evaluating destructor");
654 ExplodedNodeSet DstPreCall;
655 getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,
658 ExplodedNodeSet DstInvalidated;
659 StmtNodeBuilder Bldr(DstPreCall, DstInvalidated, *currBldrCtx);
660 for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
662 defaultEvalCall(Bldr, *I, *Call, CallOpts);
664 getCheckerManager().runCheckersForPostCall(Dst, DstInvalidated,
668 void ExprEngine::VisitCXXNewAllocatorCall(const CXXNewExpr *CNE,
670 ExplodedNodeSet &Dst) {
671 ProgramStateRef State = Pred->getState();
672 const LocationContext *LCtx = Pred->getLocationContext();
673 PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
675 "Error evaluating New Allocator Call");
676 CallEventManager &CEMgr = getStateManager().getCallEventManager();
677 CallEventRef<CXXAllocatorCall> Call =
678 CEMgr.getCXXAllocatorCall(CNE, State, LCtx);
680 ExplodedNodeSet DstPreCall;
681 getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,
684 ExplodedNodeSet DstPostCall;
685 StmtNodeBuilder CallBldr(DstPreCall, DstPostCall, *currBldrCtx);
686 for (auto I : DstPreCall) {
687 // FIXME: Provide evalCall for checkers?
688 defaultEvalCall(CallBldr, I, *Call);
690 // If the call is inlined, DstPostCall will be empty and we bail out now.
692 // Store return value of operator new() for future use, until the actual
693 // CXXNewExpr gets processed.
694 ExplodedNodeSet DstPostValue;
695 StmtNodeBuilder ValueBldr(DstPostCall, DstPostValue, *currBldrCtx);
696 for (auto I : DstPostCall) {
697 // FIXME: Because CNE serves as the "call site" for the allocator (due to
698 // lack of a better expression in the AST), the conjured return value symbol
699 // is going to be of the same type (C++ object pointer type). Technically
700 // this is not correct because the operator new's prototype always says that
701 // it returns a 'void *'. So we should change the type of the symbol,
702 // and then evaluate the cast over the symbolic pointer from 'void *' to
703 // the object pointer type. But without changing the symbol's type it
704 // is breaking too much to evaluate the no-op symbolic cast over it, so we
706 ProgramStateRef State = I->getState();
707 SVal RetVal = State->getSVal(CNE, LCtx);
709 // If this allocation function is not declared as non-throwing, failures
710 // /must/ be signalled by exceptions, and thus the return value will never
711 // be NULL. -fno-exceptions does not influence this semantics.
712 // FIXME: GCC has a -fcheck-new option, which forces it to consider the case
713 // where new can return NULL. If we end up supporting that option, we can
714 // consider adding a check for it here.
715 // C++11 [basic.stc.dynamic.allocation]p3.
716 if (const FunctionDecl *FD = CNE->getOperatorNew()) {
717 QualType Ty = FD->getType();
718 if (const auto *ProtoType = Ty->getAs<FunctionProtoType>())
719 if (!ProtoType->isNothrow())
720 State = State->assume(RetVal.castAs<DefinedOrUnknownSVal>(), true);
723 ValueBldr.generateNode(
724 CNE, I, addObjectUnderConstruction(State, CNE, LCtx, RetVal));
727 ExplodedNodeSet DstPostPostCallCallback;
728 getCheckerManager().runCheckersForPostCall(DstPostPostCallCallback,
729 DstPostValue, *Call, *this);
730 for (auto I : DstPostPostCallCallback) {
731 getCheckerManager().runCheckersForNewAllocator(
732 CNE, *getObjectUnderConstruction(I->getState(), CNE, LCtx), Dst, I,
737 void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
738 ExplodedNodeSet &Dst) {
739 // FIXME: Much of this should eventually migrate to CXXAllocatorCall.
740 // Also, we need to decide how allocators actually work -- they're not
741 // really part of the CXXNewExpr because they happen BEFORE the
742 // CXXConstructExpr subexpression. See PR12014 for some discussion.
744 unsigned blockCount = currBldrCtx->blockCount();
745 const LocationContext *LCtx = Pred->getLocationContext();
746 SVal symVal = UnknownVal();
747 FunctionDecl *FD = CNE->getOperatorNew();
749 bool IsStandardGlobalOpNewFunction =
750 FD->isReplaceableGlobalAllocationFunction();
752 ProgramStateRef State = Pred->getState();
754 // Retrieve the stored operator new() return value.
755 if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
756 symVal = *getObjectUnderConstruction(State, CNE, LCtx);
757 State = finishObjectConstruction(State, CNE, LCtx);
760 // We assume all standard global 'operator new' functions allocate memory in
761 // heap. We realize this is an approximation that might not correctly model
762 // a custom global allocator.
763 if (symVal.isUnknown()) {
764 if (IsStandardGlobalOpNewFunction)
765 symVal = svalBuilder.getConjuredHeapSymbolVal(CNE, LCtx, blockCount);
767 symVal = svalBuilder.conjureSymbolVal(nullptr, CNE, LCtx, CNE->getType(),
771 CallEventManager &CEMgr = getStateManager().getCallEventManager();
772 CallEventRef<CXXAllocatorCall> Call =
773 CEMgr.getCXXAllocatorCall(CNE, State, LCtx);
775 if (!AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
776 // Invalidate placement args.
777 // FIXME: Once we figure out how we want allocators to work,
778 // we should be using the usual pre-/(default-)eval-/post-call checkers
780 State = Call->invalidateRegions(blockCount);
784 // If this allocation function is not declared as non-throwing, failures
785 // /must/ be signalled by exceptions, and thus the return value will never
786 // be NULL. -fno-exceptions does not influence this semantics.
787 // FIXME: GCC has a -fcheck-new option, which forces it to consider the case
788 // where new can return NULL. If we end up supporting that option, we can
789 // consider adding a check for it here.
790 // C++11 [basic.stc.dynamic.allocation]p3.
792 QualType Ty = FD->getType();
793 if (const auto *ProtoType = Ty->getAs<FunctionProtoType>())
794 if (!ProtoType->isNothrow())
795 if (auto dSymVal = symVal.getAs<DefinedOrUnknownSVal>())
796 State = State->assume(*dSymVal, true);
800 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
802 SVal Result = symVal;
804 if (CNE->isArray()) {
805 // FIXME: allocating an array requires simulating the constructors.
806 // For now, just return a symbolicated region.
807 if (const auto *NewReg = cast_or_null<SubRegion>(symVal.getAsRegion())) {
808 QualType ObjTy = CNE->getType()->getPointeeType();
809 const ElementRegion *EleReg =
810 getStoreManager().GetElementZeroRegion(NewReg, ObjTy);
811 Result = loc::MemRegionVal(EleReg);
813 State = State->BindExpr(CNE, Pred->getLocationContext(), Result);
814 Bldr.generateNode(CNE, Pred, State);
818 // FIXME: Once we have proper support for CXXConstructExprs inside
819 // CXXNewExpr, we need to make sure that the constructed object is not
820 // immediately invalidated here. (The placement call should happen before
821 // the constructor call anyway.)
822 if (FD && FD->isReservedGlobalPlacementOperator()) {
823 // Non-array placement new should always return the placement location.
824 SVal PlacementLoc = State->getSVal(CNE->getPlacementArg(0), LCtx);
825 Result = svalBuilder.evalCast(PlacementLoc, CNE->getType(),
826 CNE->getPlacementArg(0)->getType());
829 // Bind the address of the object, then check to see if we cached out.
830 State = State->BindExpr(CNE, LCtx, Result);
831 ExplodedNode *NewN = Bldr.generateNode(CNE, Pred, State);
835 // If the type is not a record, we won't have a CXXConstructExpr as an
836 // initializer. Copy the value over.
837 if (const Expr *Init = CNE->getInitializer()) {
838 if (!isa<CXXConstructExpr>(Init)) {
839 assert(Bldr.getResults().size() == 1);
840 Bldr.takeNodes(NewN);
841 evalBind(Dst, CNE, NewN, Result, State->getSVal(Init, LCtx),
842 /*FirstInit=*/IsStandardGlobalOpNewFunction);
847 void ExprEngine::VisitCXXDeleteExpr(const CXXDeleteExpr *CDE,
848 ExplodedNode *Pred, ExplodedNodeSet &Dst) {
849 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
850 ProgramStateRef state = Pred->getState();
851 Bldr.generateNode(CDE, Pred, state);
854 void ExprEngine::VisitCXXCatchStmt(const CXXCatchStmt *CS,
856 ExplodedNodeSet &Dst) {
857 const VarDecl *VD = CS->getExceptionDecl();
863 const LocationContext *LCtx = Pred->getLocationContext();
864 SVal V = svalBuilder.conjureSymbolVal(CS, LCtx, VD->getType(),
865 currBldrCtx->blockCount());
866 ProgramStateRef state = Pred->getState();
867 state = state->bindLoc(state->getLValue(VD, LCtx), V, LCtx);
869 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
870 Bldr.generateNode(CS, Pred, state);
873 void ExprEngine::VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
874 ExplodedNodeSet &Dst) {
875 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
877 // Get the this object region from StoreManager.
878 const LocationContext *LCtx = Pred->getLocationContext();
880 svalBuilder.getRegionManager().getCXXThisRegion(
881 getContext().getCanonicalType(TE->getType()),
884 ProgramStateRef state = Pred->getState();
885 SVal V = state->getSVal(loc::MemRegionVal(R));
886 Bldr.generateNode(TE, Pred, state->BindExpr(TE, LCtx, V));
889 void ExprEngine::VisitLambdaExpr(const LambdaExpr *LE, ExplodedNode *Pred,
890 ExplodedNodeSet &Dst) {
891 const LocationContext *LocCtxt = Pred->getLocationContext();
893 // Get the region of the lambda itself.
894 const MemRegion *R = svalBuilder.getRegionManager().getCXXTempObjectRegion(
896 SVal V = loc::MemRegionVal(R);
898 ProgramStateRef State = Pred->getState();
900 // If we created a new MemRegion for the lambda, we should explicitly bind
902 CXXRecordDecl::field_iterator CurField = LE->getLambdaClass()->field_begin();
903 for (LambdaExpr::const_capture_init_iterator i = LE->capture_init_begin(),
904 e = LE->capture_init_end();
905 i != e; ++i, ++CurField) {
906 FieldDecl *FieldForCapture = *CurField;
907 SVal FieldLoc = State->getLValue(FieldForCapture, V);
910 if (!FieldForCapture->hasCapturedVLAType()) {
912 assert(InitExpr && "Capture missing initialization expression");
913 InitVal = State->getSVal(InitExpr, LocCtxt);
915 // The field stores the length of a captured variable-length array.
916 // These captures don't have initialization expressions; instead we
917 // get the length from the VLAType size expression.
918 Expr *SizeExpr = FieldForCapture->getCapturedVLAType()->getSizeExpr();
919 InitVal = State->getSVal(SizeExpr, LocCtxt);
922 State = State->bindLoc(FieldLoc, InitVal, LocCtxt);
925 // Decay the Loc into an RValue, because there might be a
926 // MaterializeTemporaryExpr node above this one which expects the bound value
928 SVal LambdaRVal = State->getSVal(R);
931 StmtNodeBuilder Bldr(Pred, Tmp, *currBldrCtx);
932 // FIXME: is this the right program point kind?
933 Bldr.generateNode(LE, Pred,
934 State->BindExpr(LE, LocCtxt, LambdaRVal),
935 nullptr, ProgramPoint::PostLValueKind);
937 // FIXME: Move all post/pre visits to ::Visit().
938 getCheckerManager().runCheckersForPostStmt(Dst, Tmp, LE, *this);