1 //===- ExprEngineCXX.cpp - ExprEngine support for C++ -----------*- C++ -*-===//
2 //
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
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file defines the C++ expression evaluation engine.
10 //
11 //===----------------------------------------------------------------------===//
12 
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"
22 
23 using namespace clang;
24 using namespace ento;
25 
26 void ExprEngine::CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
27                                           ExplodedNode *Pred,
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();
33 
34   state = createTemporaryRegionIfNeeded(state, LCtx, tempExpr, ME);
35   Bldr.generateNode(ME, Pred, state);
36 }
37 
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) {
42   SVal ThisVal;
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;
51   } else {
52     assert(cast<CXXMethodDecl>(Call.getDecl())->isTrivial());
53     assert(cast<CXXMethodDecl>(Call.getDecl())->getOverloadedOperator() ==
54            OO_Equal);
55     ThisVal = cast<CXXInstanceCall>(Call).getCXXThisVal();
56     ThisRD = cast<CXXMethodDecl>(Call.getDecl())->getParent();
57     AlwaysReturnsLValue = true;
58   }
59 
60   assert(ThisRD);
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.
65     return;
66   }
67 
68   const LocationContext *LCtx = Pred->getLocationContext();
69 
70   ExplodedNodeSet Dst;
71   Bldr.takeNodes(Pred);
72 
73   SVal V = Call.getArgSVal(0);
74 
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);
79   else
80     assert(V.isUnknownOrUndef());
81 
82   const Expr *CallExpr = Call.getOriginExpr();
83   evalBind(Dst, CallExpr, Pred, ThisVal, V, true);
84 
85   PostStmt PS(CallExpr, LCtx);
86   for (ExplodedNodeSet::iterator I = Dst.begin(), E = Dst.end();
87        I != E; ++I) {
88     ProgramStateRef State = (*I)->getState();
89     if (AlwaysReturnsLValue)
90       State = State->BindExpr(CallExpr, LCtx, ThisVal);
91     else
92       State = bindReturnValue(Call, LCtx, State);
93     Bldr.generateNode(PS, State, *I);
94   }
95 }
96 
97 SVal ExprEngine::makeElementRegion(ProgramStateRef State, SVal LValue,
98                                    QualType &Ty, bool &IsArray, unsigned Idx) {
99   SValBuilder &SVB = State->getStateManager().getSValBuilder();
100   ASTContext &Ctx = SVB.getContext();
101 
102   if (const ArrayType *AT = Ctx.getAsArrayType(Ty)) {
103     while (AT) {
104       Ty = AT->getElementType();
105       AT = dyn_cast<ArrayType>(AT->getElementType());
106     }
107     LValue = State->getLValue(Ty, SVB.makeArrayIndex(Idx), LValue);
108     IsArray = true;
109   }
110 
111   return LValue;
112 }
113 
114 SVal ExprEngine::computeObjectUnderConstruction(
115     const Expr *E, ProgramStateRef State, const LocationContext *LCtx,
116     const ConstructionContext *CC, EvalCallOptions &CallOpts, unsigned Idx) {
117   SValBuilder &SVB = getSValBuilder();
118   MemRegionManager &MRMgr = SVB.getRegionManager();
119   ASTContext &ACtx = SVB.getContext();
120 
121   // Compute the target region by exploring the construction context.
122   if (CC) {
123     switch (CC->getKind()) {
124     case ConstructionContext::CXX17ElidedCopyVariableKind:
125     case ConstructionContext::SimpleVariableKind: {
126       const auto *DSCC = cast<VariableConstructionContext>(CC);
127       const auto *DS = DSCC->getDeclStmt();
128       const auto *Var = cast<VarDecl>(DS->getSingleDecl());
129       QualType Ty = Var->getType();
130       return makeElementRegion(State, State->getLValue(Var, LCtx), Ty,
131                                CallOpts.IsArrayCtorOrDtor, Idx);
132     }
133     case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind:
134     case ConstructionContext::SimpleConstructorInitializerKind: {
135       const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);
136       const auto *Init = ICC->getCXXCtorInitializer();
137       const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
138       Loc ThisPtr = SVB.getCXXThis(CurCtor, LCtx->getStackFrame());
139       SVal ThisVal = State->getSVal(ThisPtr);
140       if (Init->isBaseInitializer()) {
141         const auto *ThisReg = cast<SubRegion>(ThisVal.getAsRegion());
142         const CXXRecordDecl *BaseClass =
143           Init->getBaseClass()->getAsCXXRecordDecl();
144         const auto *BaseReg =
145           MRMgr.getCXXBaseObjectRegion(BaseClass, ThisReg,
146                                        Init->isBaseVirtual());
147         return SVB.makeLoc(BaseReg);
148       }
149       if (Init->isDelegatingInitializer())
150         return ThisVal;
151 
152       const ValueDecl *Field;
153       SVal FieldVal;
154       if (Init->isIndirectMemberInitializer()) {
155         Field = Init->getIndirectMember();
156         FieldVal = State->getLValue(Init->getIndirectMember(), ThisVal);
157       } else {
158         Field = Init->getMember();
159         FieldVal = State->getLValue(Init->getMember(), ThisVal);
160       }
161 
162       QualType Ty = Field->getType();
163       return makeElementRegion(State, FieldVal, Ty, CallOpts.IsArrayCtorOrDtor,
164                                Idx);
165     }
166     case ConstructionContext::NewAllocatedObjectKind: {
167       if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
168         const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
169         const auto *NE = NECC->getCXXNewExpr();
170         SVal V = *getObjectUnderConstruction(State, NE, LCtx);
171         if (const SubRegion *MR =
172                 dyn_cast_or_null<SubRegion>(V.getAsRegion())) {
173           if (NE->isArray()) {
174             // TODO: In fact, we need to call the constructor for every
175             // allocated element, not just the first one!
176             CallOpts.IsArrayCtorOrDtor = true;
177 
178             auto R = MRMgr.getElementRegion(NE->getType()->getPointeeType(),
179                                             svalBuilder.makeArrayIndex(Idx), MR,
180                                             SVB.getContext());
181 
182             return loc::MemRegionVal(R);
183           }
184           return  V;
185         }
186         // TODO: Detect when the allocator returns a null pointer.
187         // Constructor shall not be called in this case.
188       }
189       break;
190     }
191     case ConstructionContext::SimpleReturnedValueKind:
192     case ConstructionContext::CXX17ElidedCopyReturnedValueKind: {
193       // The temporary is to be managed by the parent stack frame.
194       // So build it in the parent stack frame if we're not in the
195       // top frame of the analysis.
196       const StackFrameContext *SFC = LCtx->getStackFrame();
197       if (const LocationContext *CallerLCtx = SFC->getParent()) {
198         auto RTC = (*SFC->getCallSiteBlock())[SFC->getIndex()]
199                        .getAs<CFGCXXRecordTypedCall>();
200         if (!RTC) {
201           // We were unable to find the correct construction context for the
202           // call in the parent stack frame. This is equivalent to not being
203           // able to find construction context at all.
204           break;
205         }
206         if (isa<BlockInvocationContext>(CallerLCtx)) {
207           // Unwrap block invocation contexts. They're mostly part of
208           // the current stack frame.
209           CallerLCtx = CallerLCtx->getParent();
210           assert(!isa<BlockInvocationContext>(CallerLCtx));
211         }
212         return computeObjectUnderConstruction(
213             cast<Expr>(SFC->getCallSite()), State, CallerLCtx,
214             RTC->getConstructionContext(), CallOpts);
215       } else {
216         // We are on the top frame of the analysis. We do not know where is the
217         // object returned to. Conjure a symbolic region for the return value.
218         // TODO: We probably need a new MemRegion kind to represent the storage
219         // of that SymbolicRegion, so that we cound produce a fancy symbol
220         // instead of an anonymous conjured symbol.
221         // TODO: Do we need to track the region to avoid having it dead
222         // too early? It does die too early, at least in C++17, but because
223         // putting anything into a SymbolicRegion causes an immediate escape,
224         // it doesn't cause any leak false positives.
225         const auto *RCC = cast<ReturnedValueConstructionContext>(CC);
226         // Make sure that this doesn't coincide with any other symbol
227         // conjured for the returned expression.
228         static const int TopLevelSymRegionTag = 0;
229         const Expr *RetE = RCC->getReturnStmt()->getRetValue();
230         assert(RetE && "Void returns should not have a construction context");
231         QualType ReturnTy = RetE->getType();
232         QualType RegionTy = ACtx.getPointerType(ReturnTy);
233         return SVB.conjureSymbolVal(&TopLevelSymRegionTag, RetE, SFC, RegionTy,
234                                     currBldrCtx->blockCount());
235       }
236       llvm_unreachable("Unhandled return value construction context!");
237     }
238     case ConstructionContext::ElidedTemporaryObjectKind: {
239       assert(AMgr.getAnalyzerOptions().ShouldElideConstructors);
240       const auto *TCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
241 
242       // Support pre-C++17 copy elision. We'll have the elidable copy
243       // constructor in the AST and in the CFG, but we'll skip it
244       // and construct directly into the final object. This call
245       // also sets the CallOpts flags for us.
246       // If the elided copy/move constructor is not supported, there's still
247       // benefit in trying to model the non-elided constructor.
248       // Stash our state before trying to elide, as it'll get overwritten.
249       ProgramStateRef PreElideState = State;
250       EvalCallOptions PreElideCallOpts = CallOpts;
251 
252       SVal V = computeObjectUnderConstruction(
253           TCC->getConstructorAfterElision(), State, LCtx,
254           TCC->getConstructionContextAfterElision(), CallOpts);
255 
256       // FIXME: This definition of "copy elision has not failed" is unreliable.
257       // It doesn't indicate that the constructor will actually be inlined
258       // later; this is still up to evalCall() to decide.
259       if (!CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion)
260         return V;
261 
262       // Copy elision failed. Revert the changes and proceed as if we have
263       // a simple temporary.
264       CallOpts = PreElideCallOpts;
265       CallOpts.IsElidableCtorThatHasNotBeenElided = true;
266       LLVM_FALLTHROUGH;
267     }
268     case ConstructionContext::SimpleTemporaryObjectKind: {
269       const auto *TCC = cast<TemporaryObjectConstructionContext>(CC);
270       const MaterializeTemporaryExpr *MTE = TCC->getMaterializedTemporaryExpr();
271 
272       CallOpts.IsTemporaryCtorOrDtor = true;
273       if (MTE) {
274         if (const ValueDecl *VD = MTE->getExtendingDecl()) {
275           assert(MTE->getStorageDuration() != SD_FullExpression);
276           if (!VD->getType()->isReferenceType()) {
277             // We're lifetime-extended by a surrounding aggregate.
278             // Automatic destructors aren't quite working in this case
279             // on the CFG side. We should warn the caller about that.
280             // FIXME: Is there a better way to retrieve this information from
281             // the MaterializeTemporaryExpr?
282             CallOpts.IsTemporaryLifetimeExtendedViaAggregate = true;
283           }
284         }
285 
286         if (MTE->getStorageDuration() == SD_Static ||
287             MTE->getStorageDuration() == SD_Thread)
288           return loc::MemRegionVal(MRMgr.getCXXStaticTempObjectRegion(E));
289       }
290 
291       return loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));
292     }
293     case ConstructionContext::ArgumentKind: {
294       // Arguments are technically temporaries.
295       CallOpts.IsTemporaryCtorOrDtor = true;
296 
297       const auto *ACC = cast<ArgumentConstructionContext>(CC);
298       const Expr *E = ACC->getCallLikeExpr();
299       unsigned Idx = ACC->getIndex();
300 
301       CallEventManager &CEMgr = getStateManager().getCallEventManager();
302       auto getArgLoc = [&](CallEventRef<> Caller) -> Optional<SVal> {
303         const LocationContext *FutureSFC =
304             Caller->getCalleeStackFrame(currBldrCtx->blockCount());
305         // Return early if we are unable to reliably foresee
306         // the future stack frame.
307         if (!FutureSFC)
308           return None;
309 
310         // This should be equivalent to Caller->getDecl() for now, but
311         // FutureSFC->getDecl() is likely to support better stuff (like
312         // virtual functions) earlier.
313         const Decl *CalleeD = FutureSFC->getDecl();
314 
315         // FIXME: Support for variadic arguments is not implemented here yet.
316         if (CallEvent::isVariadic(CalleeD))
317           return None;
318 
319         // Operator arguments do not correspond to operator parameters
320         // because this-argument is implemented as a normal argument in
321         // operator call expressions but not in operator declarations.
322         const TypedValueRegion *TVR = Caller->getParameterLocation(
323             *Caller->getAdjustedParameterIndex(Idx), currBldrCtx->blockCount());
324         if (!TVR)
325           return None;
326 
327         return loc::MemRegionVal(TVR);
328       };
329 
330       if (const auto *CE = dyn_cast<CallExpr>(E)) {
331         CallEventRef<> Caller = CEMgr.getSimpleCall(CE, State, LCtx);
332         if (Optional<SVal> V = getArgLoc(Caller))
333           return *V;
334         else
335           break;
336       } else if (const auto *CCE = dyn_cast<CXXConstructExpr>(E)) {
337         // Don't bother figuring out the target region for the future
338         // constructor because we won't need it.
339         CallEventRef<> Caller =
340             CEMgr.getCXXConstructorCall(CCE, /*Target=*/nullptr, State, LCtx);
341         if (Optional<SVal> V = getArgLoc(Caller))
342           return *V;
343         else
344           break;
345       } else if (const auto *ME = dyn_cast<ObjCMessageExpr>(E)) {
346         CallEventRef<> Caller = CEMgr.getObjCMethodCall(ME, State, LCtx);
347         if (Optional<SVal> V = getArgLoc(Caller))
348           return *V;
349         else
350           break;
351       }
352     }
353     } // switch (CC->getKind())
354   }
355 
356   // If we couldn't find an existing region to construct into, assume we're
357   // constructing a temporary. Notify the caller of our failure.
358   CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
359   return loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));
360 }
361 
362 ProgramStateRef ExprEngine::updateObjectsUnderConstruction(
363     SVal V, const Expr *E, ProgramStateRef State, const LocationContext *LCtx,
364     const ConstructionContext *CC, const EvalCallOptions &CallOpts) {
365   if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) {
366     // Sounds like we failed to find the target region and therefore
367     // copy elision failed. There's nothing we can do about it here.
368     return State;
369   }
370 
371   // See if we're constructing an existing region by looking at the
372   // current construction context.
373   assert(CC && "Computed target region without construction context?");
374   switch (CC->getKind()) {
375   case ConstructionContext::CXX17ElidedCopyVariableKind:
376   case ConstructionContext::SimpleVariableKind: {
377     const auto *DSCC = cast<VariableConstructionContext>(CC);
378     return addObjectUnderConstruction(State, DSCC->getDeclStmt(), LCtx, V);
379     }
380     case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind:
381     case ConstructionContext::SimpleConstructorInitializerKind: {
382       const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);
383       const auto *Init = ICC->getCXXCtorInitializer();
384       // Base and delegating initializers handled above
385       assert(Init->isAnyMemberInitializer() &&
386              "Base and delegating initializers should have been handled by"
387              "computeObjectUnderConstruction()");
388       return addObjectUnderConstruction(State, Init, LCtx, V);
389     }
390     case ConstructionContext::NewAllocatedObjectKind: {
391       return State;
392     }
393     case ConstructionContext::SimpleReturnedValueKind:
394     case ConstructionContext::CXX17ElidedCopyReturnedValueKind: {
395       const StackFrameContext *SFC = LCtx->getStackFrame();
396       const LocationContext *CallerLCtx = SFC->getParent();
397       if (!CallerLCtx) {
398         // No extra work is necessary in top frame.
399         return State;
400       }
401 
402       auto RTC = (*SFC->getCallSiteBlock())[SFC->getIndex()]
403                      .getAs<CFGCXXRecordTypedCall>();
404       assert(RTC && "Could not have had a target region without it");
405       if (isa<BlockInvocationContext>(CallerLCtx)) {
406         // Unwrap block invocation contexts. They're mostly part of
407         // the current stack frame.
408         CallerLCtx = CallerLCtx->getParent();
409         assert(!isa<BlockInvocationContext>(CallerLCtx));
410       }
411 
412       return updateObjectsUnderConstruction(V,
413           cast<Expr>(SFC->getCallSite()), State, CallerLCtx,
414           RTC->getConstructionContext(), CallOpts);
415     }
416     case ConstructionContext::ElidedTemporaryObjectKind: {
417       assert(AMgr.getAnalyzerOptions().ShouldElideConstructors);
418       if (!CallOpts.IsElidableCtorThatHasNotBeenElided) {
419         const auto *TCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
420         State = updateObjectsUnderConstruction(
421             V, TCC->getConstructorAfterElision(), State, LCtx,
422             TCC->getConstructionContextAfterElision(), CallOpts);
423 
424         // Remember that we've elided the constructor.
425         State = addObjectUnderConstruction(
426             State, TCC->getConstructorAfterElision(), LCtx, V);
427 
428         // Remember that we've elided the destructor.
429         if (const auto *BTE = TCC->getCXXBindTemporaryExpr())
430           State = elideDestructor(State, BTE, LCtx);
431 
432         // Instead of materialization, shamelessly return
433         // the final object destination.
434         if (const auto *MTE = TCC->getMaterializedTemporaryExpr())
435           State = addObjectUnderConstruction(State, MTE, LCtx, V);
436 
437         return State;
438       }
439       // If we decided not to elide the constructor, proceed as if
440       // it's a simple temporary.
441       LLVM_FALLTHROUGH;
442     }
443     case ConstructionContext::SimpleTemporaryObjectKind: {
444       const auto *TCC = cast<TemporaryObjectConstructionContext>(CC);
445       if (const auto *BTE = TCC->getCXXBindTemporaryExpr())
446         State = addObjectUnderConstruction(State, BTE, LCtx, V);
447 
448       if (const auto *MTE = TCC->getMaterializedTemporaryExpr())
449         State = addObjectUnderConstruction(State, MTE, LCtx, V);
450 
451       return State;
452     }
453     case ConstructionContext::ArgumentKind: {
454       const auto *ACC = cast<ArgumentConstructionContext>(CC);
455       if (const auto *BTE = ACC->getCXXBindTemporaryExpr())
456         State = addObjectUnderConstruction(State, BTE, LCtx, V);
457 
458       return addObjectUnderConstruction(
459           State, {ACC->getCallLikeExpr(), ACC->getIndex()}, LCtx, V);
460     }
461   }
462   llvm_unreachable("Unhandled construction context!");
463 }
464 
465 static ProgramStateRef
466 bindRequiredArrayElementToEnvironment(ProgramStateRef State,
467                                       const ArrayInitLoopExpr *AILE,
468                                       const LocationContext *LCtx, SVal Idx) {
469   // The ctor in this case is guaranteed to be a copy ctor, otherwise we hit a
470   // compile time error.
471   //
472   //  -ArrayInitLoopExpr                <-- we're here
473   //   |-OpaqueValueExpr
474   //   | `-DeclRefExpr                  <-- match this
475   //   `-CXXConstructExpr
476   //     `-ImplicitCastExpr
477   //       `-ArraySubscriptExpr
478   //         |-ImplicitCastExpr
479   //         | `-OpaqueValueExpr
480   //         |   `-DeclRefExpr
481   //         `-ArrayInitIndexExpr
482   //
483   // The resulting expression might look like the one below in an implicit
484   // copy/move ctor.
485   //
486   //   ArrayInitLoopExpr                <-- we're here
487   //   |-OpaqueValueExpr
488   //   | `-MemberExpr                   <-- match this
489   //   |  (`-CXXStaticCastExpr)         <-- move ctor only
490   //   |     `-DeclRefExpr
491   //   `-CXXConstructExpr
492   //     `-ArraySubscriptExpr
493   //       |-ImplicitCastExpr
494   //       | `-OpaqueValueExpr
495   //       |   `-MemberExpr
496   //       |     `-DeclRefExpr
497   //       `-ArrayInitIndexExpr
498   //
499   // HACK: There is no way we can put the index of the array element into the
500   // CFG unless we unroll the loop, so we manually select and bind the required
501   // parameter to the environment.
502   const auto *CE = cast<CXXConstructExpr>(AILE->getSubExpr());
503   const auto *OVESrc = AILE->getCommonExpr()->getSourceExpr();
504 
505   SVal Base = UnknownVal();
506   if (const auto *ME = dyn_cast<MemberExpr>(OVESrc))
507     Base = State->getSVal(ME, LCtx);
508   else if (const auto *DRE = cast<DeclRefExpr>(OVESrc))
509     Base = State->getLValue(cast<VarDecl>(DRE->getDecl()), LCtx);
510   else
511     llvm_unreachable("ArrayInitLoopExpr contains unexpected source expression");
512 
513   SVal NthElem = State->getLValue(CE->getType(), Idx, Base);
514 
515   return State->BindExpr(CE->getArg(0), LCtx, NthElem);
516 }
517 
518 void ExprEngine::handleConstructor(const Expr *E,
519                                    ExplodedNode *Pred,
520                                    ExplodedNodeSet &destNodes) {
521   const auto *CE = dyn_cast<CXXConstructExpr>(E);
522   const auto *CIE = dyn_cast<CXXInheritedCtorInitExpr>(E);
523   assert(CE || CIE);
524 
525   const LocationContext *LCtx = Pred->getLocationContext();
526   ProgramStateRef State = Pred->getState();
527 
528   SVal Target = UnknownVal();
529 
530   if (CE) {
531     if (Optional<SVal> ElidedTarget =
532             getObjectUnderConstruction(State, CE, LCtx)) {
533       // We've previously modeled an elidable constructor by pretending that it
534       // in fact constructs into the correct target. This constructor can
535       // therefore be skipped.
536       Target = *ElidedTarget;
537       StmtNodeBuilder Bldr(Pred, destNodes, *currBldrCtx);
538       State = finishObjectConstruction(State, CE, LCtx);
539       if (auto L = Target.getAs<Loc>())
540         State = State->BindExpr(CE, LCtx, State->getSVal(*L, CE->getType()));
541       Bldr.generateNode(CE, Pred, State);
542       return;
543     }
544   }
545 
546   EvalCallOptions CallOpts;
547   auto C = getCurrentCFGElement().getAs<CFGConstructor>();
548   assert(C || getCurrentCFGElement().getAs<CFGStmt>());
549   const ConstructionContext *CC = C ? C->getConstructionContext() : nullptr;
550 
551   const CXXConstructExpr::ConstructionKind CK =
552       CE ? CE->getConstructionKind() : CIE->getConstructionKind();
553   switch (CK) {
554   case CXXConstructExpr::CK_Complete: {
555     // Inherited constructors are always base class constructors.
556     assert(CE && !CIE && "A complete constructor is inherited?!");
557 
558     // If the ctor is part of an ArrayInitLoopExpr, we want to handle it
559     // differently.
560     auto *AILE = CC ? CC->getArrayInitLoop() : nullptr;
561 
562     unsigned Idx = 0;
563     if (CE->getType()->isArrayType() || AILE) {
564       Idx = getIndexOfElementToConstruct(State, CE, LCtx).getValueOr(0u);
565       State = setIndexOfElementToConstruct(State, CE, LCtx, Idx + 1);
566     }
567 
568     if (AILE) {
569       // Only set this once even though we loop through it multiple times.
570       if (!getPendingInitLoop(State, CE, LCtx))
571         State = setPendingInitLoop(State, CE, LCtx,
572                                    AILE->getArraySize().getLimitedValue());
573 
574       State = bindRequiredArrayElementToEnvironment(
575           State, AILE, LCtx, svalBuilder.makeArrayIndex(Idx));
576     }
577 
578     // The target region is found from construction context.
579     std::tie(State, Target) =
580         handleConstructionContext(CE, State, LCtx, CC, CallOpts, Idx);
581     break;
582   }
583   case CXXConstructExpr::CK_VirtualBase: {
584     // Make sure we are not calling virtual base class initializers twice.
585     // Only the most-derived object should initialize virtual base classes.
586     const auto *OuterCtor = dyn_cast_or_null<CXXConstructExpr>(
587         LCtx->getStackFrame()->getCallSite());
588     assert(
589         (!OuterCtor ||
590          OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Complete ||
591          OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Delegating) &&
592         ("This virtual base should have already been initialized by "
593          "the most derived class!"));
594     (void)OuterCtor;
595     LLVM_FALLTHROUGH;
596   }
597   case CXXConstructExpr::CK_NonVirtualBase:
598     // In C++17, classes with non-virtual bases may be aggregates, so they would
599     // be initialized as aggregates without a constructor call, so we may have
600     // a base class constructed directly into an initializer list without
601     // having the derived-class constructor call on the previous stack frame.
602     // Initializer lists may be nested into more initializer lists that
603     // correspond to surrounding aggregate initializations.
604     // FIXME: For now this code essentially bails out. We need to find the
605     // correct target region and set it.
606     // FIXME: Instead of relying on the ParentMap, we should have the
607     // trigger-statement (InitListExpr in this case) passed down from CFG or
608     // otherwise always available during construction.
609     if (isa_and_nonnull<InitListExpr>(LCtx->getParentMap().getParent(E))) {
610       MemRegionManager &MRMgr = getSValBuilder().getRegionManager();
611       Target = loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));
612       CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
613       break;
614     }
615     LLVM_FALLTHROUGH;
616   case CXXConstructExpr::CK_Delegating: {
617     const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
618     Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor,
619                                               LCtx->getStackFrame());
620     SVal ThisVal = State->getSVal(ThisPtr);
621 
622     if (CK == CXXConstructExpr::CK_Delegating) {
623       Target = ThisVal;
624     } else {
625       // Cast to the base type.
626       bool IsVirtual = (CK == CXXConstructExpr::CK_VirtualBase);
627       SVal BaseVal =
628           getStoreManager().evalDerivedToBase(ThisVal, E->getType(), IsVirtual);
629       Target = BaseVal;
630     }
631     break;
632   }
633   }
634 
635   if (State != Pred->getState()) {
636     static SimpleProgramPointTag T("ExprEngine",
637                                    "Prepare for object construction");
638     ExplodedNodeSet DstPrepare;
639     StmtNodeBuilder BldrPrepare(Pred, DstPrepare, *currBldrCtx);
640     BldrPrepare.generateNode(E, Pred, State, &T, ProgramPoint::PreStmtKind);
641     assert(DstPrepare.size() <= 1);
642     if (DstPrepare.size() == 0)
643       return;
644     Pred = *BldrPrepare.begin();
645   }
646 
647   const MemRegion *TargetRegion = Target.getAsRegion();
648   CallEventManager &CEMgr = getStateManager().getCallEventManager();
649   CallEventRef<> Call =
650       CIE ? (CallEventRef<>)CEMgr.getCXXInheritedConstructorCall(
651                 CIE, TargetRegion, State, LCtx)
652           : (CallEventRef<>)CEMgr.getCXXConstructorCall(
653                 CE, TargetRegion, State, LCtx);
654 
655   ExplodedNodeSet DstPreVisit;
656   getCheckerManager().runCheckersForPreStmt(DstPreVisit, Pred, E, *this);
657 
658   ExplodedNodeSet PreInitialized;
659   if (CE) {
660     // FIXME: Is it possible and/or useful to do this before PreStmt?
661     StmtNodeBuilder Bldr(DstPreVisit, PreInitialized, *currBldrCtx);
662     for (ExplodedNodeSet::iterator I = DstPreVisit.begin(),
663                                    E = DstPreVisit.end();
664          I != E; ++I) {
665       ProgramStateRef State = (*I)->getState();
666       if (CE->requiresZeroInitialization()) {
667         // FIXME: Once we properly handle constructors in new-expressions, we'll
668         // need to invalidate the region before setting a default value, to make
669         // sure there aren't any lingering bindings around. This probably needs
670         // to happen regardless of whether or not the object is zero-initialized
671         // to handle random fields of a placement-initialized object picking up
672         // old bindings. We might only want to do it when we need to, though.
673         // FIXME: This isn't actually correct for arrays -- we need to zero-
674         // initialize the entire array, not just the first element -- but our
675         // handling of arrays everywhere else is weak as well, so this shouldn't
676         // actually make things worse. Placement new makes this tricky as well,
677         // since it's then possible to be initializing one part of a multi-
678         // dimensional array.
679         State = State->bindDefaultZero(Target, LCtx);
680       }
681 
682       Bldr.generateNode(CE, *I, State, /*tag=*/nullptr,
683                         ProgramPoint::PreStmtKind);
684     }
685   } else {
686     PreInitialized = DstPreVisit;
687   }
688 
689   ExplodedNodeSet DstPreCall;
690   getCheckerManager().runCheckersForPreCall(DstPreCall, PreInitialized,
691                                             *Call, *this);
692 
693   ExplodedNodeSet DstEvaluated;
694 
695   if (CE && CE->getConstructor()->isTrivial() &&
696       CE->getConstructor()->isCopyOrMoveConstructor() &&
697       !CallOpts.IsArrayCtorOrDtor) {
698     StmtNodeBuilder Bldr(DstPreCall, DstEvaluated, *currBldrCtx);
699     // FIXME: Handle other kinds of trivial constructors as well.
700     for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
701          I != E; ++I)
702       performTrivialCopy(Bldr, *I, *Call);
703 
704   } else {
705     for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
706          I != E; ++I)
707       getCheckerManager().runCheckersForEvalCall(DstEvaluated, *I, *Call, *this,
708                                                  CallOpts);
709   }
710 
711   // If the CFG was constructed without elements for temporary destructors
712   // and the just-called constructor created a temporary object then
713   // stop exploration if the temporary object has a noreturn constructor.
714   // This can lose coverage because the destructor, if it were present
715   // in the CFG, would be called at the end of the full expression or
716   // later (for life-time extended temporaries) -- but avoids infeasible
717   // paths when no-return temporary destructors are used for assertions.
718   ExplodedNodeSet DstEvaluatedPostProcessed;
719   StmtNodeBuilder Bldr(DstEvaluated, DstEvaluatedPostProcessed, *currBldrCtx);
720   const AnalysisDeclContext *ADC = LCtx->getAnalysisDeclContext();
721   if (!ADC->getCFGBuildOptions().AddTemporaryDtors) {
722     if (llvm::isa_and_nonnull<CXXTempObjectRegion>(TargetRegion) &&
723         cast<CXXConstructorDecl>(Call->getDecl())
724             ->getParent()
725             ->isAnyDestructorNoReturn()) {
726 
727       // If we've inlined the constructor, then DstEvaluated would be empty.
728       // In this case we still want a sink, which could be implemented
729       // in processCallExit. But we don't have that implemented at the moment,
730       // so if you hit this assertion, see if you can avoid inlining
731       // the respective constructor when analyzer-config cfg-temporary-dtors
732       // is set to false.
733       // Otherwise there's nothing wrong with inlining such constructor.
734       assert(!DstEvaluated.empty() &&
735              "We should not have inlined this constructor!");
736 
737       for (ExplodedNode *N : DstEvaluated) {
738         Bldr.generateSink(E, N, N->getState());
739       }
740 
741       // There is no need to run the PostCall and PostStmt checker
742       // callbacks because we just generated sinks on all nodes in th
743       // frontier.
744       return;
745     }
746   }
747 
748   ExplodedNodeSet DstPostArgumentCleanup;
749   for (ExplodedNode *I : DstEvaluatedPostProcessed)
750     finishArgumentConstruction(DstPostArgumentCleanup, I, *Call);
751 
752   // If there were other constructors called for object-type arguments
753   // of this constructor, clean them up.
754   ExplodedNodeSet DstPostCall;
755   getCheckerManager().runCheckersForPostCall(DstPostCall,
756                                              DstPostArgumentCleanup,
757                                              *Call, *this);
758   getCheckerManager().runCheckersForPostStmt(destNodes, DstPostCall, E, *this);
759 }
760 
761 void ExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *CE,
762                                        ExplodedNode *Pred,
763                                        ExplodedNodeSet &Dst) {
764   handleConstructor(CE, Pred, Dst);
765 }
766 
767 void ExprEngine::VisitCXXInheritedCtorInitExpr(
768     const CXXInheritedCtorInitExpr *CE, ExplodedNode *Pred,
769     ExplodedNodeSet &Dst) {
770   handleConstructor(CE, Pred, Dst);
771 }
772 
773 void ExprEngine::VisitCXXDestructor(QualType ObjectType,
774                                     const MemRegion *Dest,
775                                     const Stmt *S,
776                                     bool IsBaseDtor,
777                                     ExplodedNode *Pred,
778                                     ExplodedNodeSet &Dst,
779                                     EvalCallOptions &CallOpts) {
780   assert(S && "A destructor without a trigger!");
781   const LocationContext *LCtx = Pred->getLocationContext();
782   ProgramStateRef State = Pred->getState();
783 
784   const CXXRecordDecl *RecordDecl = ObjectType->getAsCXXRecordDecl();
785   assert(RecordDecl && "Only CXXRecordDecls should have destructors");
786   const CXXDestructorDecl *DtorDecl = RecordDecl->getDestructor();
787   // FIXME: There should always be a Decl, otherwise the destructor call
788   // shouldn't have been added to the CFG in the first place.
789   if (!DtorDecl) {
790     // Skip the invalid destructor. We cannot simply return because
791     // it would interrupt the analysis instead.
792     static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");
793     // FIXME: PostImplicitCall with a null decl may crash elsewhere anyway.
794     PostImplicitCall PP(/*Decl=*/nullptr, S->getEndLoc(), LCtx, &T);
795     NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
796     Bldr.generateNode(PP, Pred->getState(), Pred);
797     return;
798   }
799 
800   if (!Dest) {
801     // We're trying to destroy something that is not a region. This may happen
802     // for a variety of reasons (unknown target region, concrete integer instead
803     // of target region, etc.). The current code makes an attempt to recover.
804     // FIXME: We probably don't really need to recover when we're dealing
805     // with concrete integers specifically.
806     CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
807     if (const Expr *E = dyn_cast_or_null<Expr>(S)) {
808       Dest = MRMgr.getCXXTempObjectRegion(E, Pred->getLocationContext());
809     } else {
810       static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");
811       NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
812       Bldr.generateSink(Pred->getLocation().withTag(&T),
813                         Pred->getState(), Pred);
814       return;
815     }
816   }
817 
818   CallEventManager &CEMgr = getStateManager().getCallEventManager();
819   CallEventRef<CXXDestructorCall> Call =
820       CEMgr.getCXXDestructorCall(DtorDecl, S, Dest, IsBaseDtor, State, LCtx);
821 
822   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
823                                 Call->getSourceRange().getBegin(),
824                                 "Error evaluating destructor");
825 
826   ExplodedNodeSet DstPreCall;
827   getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,
828                                             *Call, *this);
829 
830   ExplodedNodeSet DstInvalidated;
831   StmtNodeBuilder Bldr(DstPreCall, DstInvalidated, *currBldrCtx);
832   for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
833        I != E; ++I)
834     defaultEvalCall(Bldr, *I, *Call, CallOpts);
835 
836   getCheckerManager().runCheckersForPostCall(Dst, DstInvalidated,
837                                              *Call, *this);
838 }
839 
840 void ExprEngine::VisitCXXNewAllocatorCall(const CXXNewExpr *CNE,
841                                           ExplodedNode *Pred,
842                                           ExplodedNodeSet &Dst) {
843   ProgramStateRef State = Pred->getState();
844   const LocationContext *LCtx = Pred->getLocationContext();
845   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
846                                 CNE->getBeginLoc(),
847                                 "Error evaluating New Allocator Call");
848   CallEventManager &CEMgr = getStateManager().getCallEventManager();
849   CallEventRef<CXXAllocatorCall> Call =
850     CEMgr.getCXXAllocatorCall(CNE, State, LCtx);
851 
852   ExplodedNodeSet DstPreCall;
853   getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,
854                                             *Call, *this);
855 
856   ExplodedNodeSet DstPostCall;
857   StmtNodeBuilder CallBldr(DstPreCall, DstPostCall, *currBldrCtx);
858   for (ExplodedNode *I : DstPreCall) {
859     // FIXME: Provide evalCall for checkers?
860     defaultEvalCall(CallBldr, I, *Call);
861   }
862   // If the call is inlined, DstPostCall will be empty and we bail out now.
863 
864   // Store return value of operator new() for future use, until the actual
865   // CXXNewExpr gets processed.
866   ExplodedNodeSet DstPostValue;
867   StmtNodeBuilder ValueBldr(DstPostCall, DstPostValue, *currBldrCtx);
868   for (ExplodedNode *I : DstPostCall) {
869     // FIXME: Because CNE serves as the "call site" for the allocator (due to
870     // lack of a better expression in the AST), the conjured return value symbol
871     // is going to be of the same type (C++ object pointer type). Technically
872     // this is not correct because the operator new's prototype always says that
873     // it returns a 'void *'. So we should change the type of the symbol,
874     // and then evaluate the cast over the symbolic pointer from 'void *' to
875     // the object pointer type. But without changing the symbol's type it
876     // is breaking too much to evaluate the no-op symbolic cast over it, so we
877     // skip it for now.
878     ProgramStateRef State = I->getState();
879     SVal RetVal = State->getSVal(CNE, LCtx);
880 
881     // If this allocation function is not declared as non-throwing, failures
882     // /must/ be signalled by exceptions, and thus the return value will never
883     // be NULL. -fno-exceptions does not influence this semantics.
884     // FIXME: GCC has a -fcheck-new option, which forces it to consider the case
885     // where new can return NULL. If we end up supporting that option, we can
886     // consider adding a check for it here.
887     // C++11 [basic.stc.dynamic.allocation]p3.
888     if (const FunctionDecl *FD = CNE->getOperatorNew()) {
889       QualType Ty = FD->getType();
890       if (const auto *ProtoType = Ty->getAs<FunctionProtoType>())
891         if (!ProtoType->isNothrow())
892           State = State->assume(RetVal.castAs<DefinedOrUnknownSVal>(), true);
893     }
894 
895     ValueBldr.generateNode(
896         CNE, I, addObjectUnderConstruction(State, CNE, LCtx, RetVal));
897   }
898 
899   ExplodedNodeSet DstPostPostCallCallback;
900   getCheckerManager().runCheckersForPostCall(DstPostPostCallCallback,
901                                              DstPostValue, *Call, *this);
902   for (ExplodedNode *I : DstPostPostCallCallback) {
903     getCheckerManager().runCheckersForNewAllocator(*Call, Dst, I, *this);
904   }
905 }
906 
907 void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
908                                    ExplodedNodeSet &Dst) {
909   // FIXME: Much of this should eventually migrate to CXXAllocatorCall.
910   // Also, we need to decide how allocators actually work -- they're not
911   // really part of the CXXNewExpr because they happen BEFORE the
912   // CXXConstructExpr subexpression. See PR12014 for some discussion.
913 
914   unsigned blockCount = currBldrCtx->blockCount();
915   const LocationContext *LCtx = Pred->getLocationContext();
916   SVal symVal = UnknownVal();
917   FunctionDecl *FD = CNE->getOperatorNew();
918 
919   bool IsStandardGlobalOpNewFunction =
920       FD->isReplaceableGlobalAllocationFunction();
921 
922   ProgramStateRef State = Pred->getState();
923 
924   // Retrieve the stored operator new() return value.
925   if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
926     symVal = *getObjectUnderConstruction(State, CNE, LCtx);
927     State = finishObjectConstruction(State, CNE, LCtx);
928   }
929 
930   // We assume all standard global 'operator new' functions allocate memory in
931   // heap. We realize this is an approximation that might not correctly model
932   // a custom global allocator.
933   if (symVal.isUnknown()) {
934     if (IsStandardGlobalOpNewFunction)
935       symVal = svalBuilder.getConjuredHeapSymbolVal(CNE, LCtx, blockCount);
936     else
937       symVal = svalBuilder.conjureSymbolVal(nullptr, CNE, LCtx, CNE->getType(),
938                                             blockCount);
939   }
940 
941   CallEventManager &CEMgr = getStateManager().getCallEventManager();
942   CallEventRef<CXXAllocatorCall> Call =
943     CEMgr.getCXXAllocatorCall(CNE, State, LCtx);
944 
945   if (!AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
946     // Invalidate placement args.
947     // FIXME: Once we figure out how we want allocators to work,
948     // we should be using the usual pre-/(default-)eval-/post-call checkers
949     // here.
950     State = Call->invalidateRegions(blockCount);
951     if (!State)
952       return;
953 
954     // If this allocation function is not declared as non-throwing, failures
955     // /must/ be signalled by exceptions, and thus the return value will never
956     // be NULL. -fno-exceptions does not influence this semantics.
957     // FIXME: GCC has a -fcheck-new option, which forces it to consider the case
958     // where new can return NULL. If we end up supporting that option, we can
959     // consider adding a check for it here.
960     // C++11 [basic.stc.dynamic.allocation]p3.
961     if (const auto *ProtoType = FD->getType()->getAs<FunctionProtoType>())
962       if (!ProtoType->isNothrow())
963         if (auto dSymVal = symVal.getAs<DefinedOrUnknownSVal>())
964           State = State->assume(*dSymVal, true);
965   }
966 
967   StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
968 
969   SVal Result = symVal;
970 
971   if (CNE->isArray()) {
972 
973     if (const auto *NewReg = cast_or_null<SubRegion>(symVal.getAsRegion())) {
974       // If each element is initialized by their default constructor, the field
975       // values are properly placed inside the required region, however if an
976       // initializer list is used, this doesn't happen automatically.
977       auto *Init = CNE->getInitializer();
978       bool isInitList = isa_and_nonnull<InitListExpr>(Init);
979 
980       QualType ObjTy =
981           isInitList ? Init->getType() : CNE->getType()->getPointeeType();
982       const ElementRegion *EleReg =
983           MRMgr.getElementRegion(ObjTy, svalBuilder.makeArrayIndex(0), NewReg,
984                                  svalBuilder.getContext());
985       Result = loc::MemRegionVal(EleReg);
986 
987       // If the array is list initialized, we bind the initializer list to the
988       // memory region here, otherwise we would lose it.
989       if (isInitList) {
990         Bldr.takeNodes(Pred);
991         Pred = Bldr.generateNode(CNE, Pred, State);
992 
993         SVal V = State->getSVal(Init, LCtx);
994         ExplodedNodeSet evaluated;
995         evalBind(evaluated, CNE, Pred, Result, V, true);
996 
997         Bldr.takeNodes(Pred);
998         Bldr.addNodes(evaluated);
999 
1000         Pred = *evaluated.begin();
1001         State = Pred->getState();
1002       }
1003     }
1004 
1005     State = State->BindExpr(CNE, Pred->getLocationContext(), Result);
1006     Bldr.generateNode(CNE, Pred, State);
1007     return;
1008   }
1009 
1010   // FIXME: Once we have proper support for CXXConstructExprs inside
1011   // CXXNewExpr, we need to make sure that the constructed object is not
1012   // immediately invalidated here. (The placement call should happen before
1013   // the constructor call anyway.)
1014   if (FD->isReservedGlobalPlacementOperator()) {
1015     // Non-array placement new should always return the placement location.
1016     SVal PlacementLoc = State->getSVal(CNE->getPlacementArg(0), LCtx);
1017     Result = svalBuilder.evalCast(PlacementLoc, CNE->getType(),
1018                                   CNE->getPlacementArg(0)->getType());
1019   }
1020 
1021   // Bind the address of the object, then check to see if we cached out.
1022   State = State->BindExpr(CNE, LCtx, Result);
1023   ExplodedNode *NewN = Bldr.generateNode(CNE, Pred, State);
1024   if (!NewN)
1025     return;
1026 
1027   // If the type is not a record, we won't have a CXXConstructExpr as an
1028   // initializer. Copy the value over.
1029   if (const Expr *Init = CNE->getInitializer()) {
1030     if (!isa<CXXConstructExpr>(Init)) {
1031       assert(Bldr.getResults().size() == 1);
1032       Bldr.takeNodes(NewN);
1033       evalBind(Dst, CNE, NewN, Result, State->getSVal(Init, LCtx),
1034                /*FirstInit=*/IsStandardGlobalOpNewFunction);
1035     }
1036   }
1037 }
1038 
1039 void ExprEngine::VisitCXXDeleteExpr(const CXXDeleteExpr *CDE,
1040                                     ExplodedNode *Pred, ExplodedNodeSet &Dst) {
1041 
1042   CallEventManager &CEMgr = getStateManager().getCallEventManager();
1043   CallEventRef<CXXDeallocatorCall> Call = CEMgr.getCXXDeallocatorCall(
1044       CDE, Pred->getState(), Pred->getLocationContext());
1045 
1046   ExplodedNodeSet DstPreCall;
1047   getCheckerManager().runCheckersForPreCall(DstPreCall, Pred, *Call, *this);
1048   ExplodedNodeSet DstPostCall;
1049 
1050   if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
1051     StmtNodeBuilder Bldr(DstPreCall, DstPostCall, *currBldrCtx);
1052     for (ExplodedNode *I : DstPreCall) {
1053       defaultEvalCall(Bldr, I, *Call);
1054     }
1055   } else {
1056     DstPostCall = DstPreCall;
1057   }
1058   getCheckerManager().runCheckersForPostCall(Dst, DstPostCall, *Call, *this);
1059 }
1060 
1061 void ExprEngine::VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred,
1062                                    ExplodedNodeSet &Dst) {
1063   const VarDecl *VD = CS->getExceptionDecl();
1064   if (!VD) {
1065     Dst.Add(Pred);
1066     return;
1067   }
1068 
1069   const LocationContext *LCtx = Pred->getLocationContext();
1070   SVal V = svalBuilder.conjureSymbolVal(CS, LCtx, VD->getType(),
1071                                         currBldrCtx->blockCount());
1072   ProgramStateRef state = Pred->getState();
1073   state = state->bindLoc(state->getLValue(VD, LCtx), V, LCtx);
1074 
1075   StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
1076   Bldr.generateNode(CS, Pred, state);
1077 }
1078 
1079 void ExprEngine::VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
1080                                     ExplodedNodeSet &Dst) {
1081   StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
1082 
1083   // Get the this object region from StoreManager.
1084   const LocationContext *LCtx = Pred->getLocationContext();
1085   const MemRegion *R =
1086     svalBuilder.getRegionManager().getCXXThisRegion(
1087                                   getContext().getCanonicalType(TE->getType()),
1088                                                     LCtx);
1089 
1090   ProgramStateRef state = Pred->getState();
1091   SVal V = state->getSVal(loc::MemRegionVal(R));
1092   Bldr.generateNode(TE, Pred, state->BindExpr(TE, LCtx, V));
1093 }
1094 
1095 void ExprEngine::VisitLambdaExpr(const LambdaExpr *LE, ExplodedNode *Pred,
1096                                  ExplodedNodeSet &Dst) {
1097   const LocationContext *LocCtxt = Pred->getLocationContext();
1098 
1099   // Get the region of the lambda itself.
1100   const MemRegion *R = svalBuilder.getRegionManager().getCXXTempObjectRegion(
1101       LE, LocCtxt);
1102   SVal V = loc::MemRegionVal(R);
1103 
1104   ProgramStateRef State = Pred->getState();
1105 
1106   // If we created a new MemRegion for the lambda, we should explicitly bind
1107   // the captures.
1108   CXXRecordDecl::field_iterator CurField = LE->getLambdaClass()->field_begin();
1109   for (LambdaExpr::const_capture_init_iterator i = LE->capture_init_begin(),
1110                                                e = LE->capture_init_end();
1111        i != e; ++i, ++CurField) {
1112     FieldDecl *FieldForCapture = *CurField;
1113     SVal FieldLoc = State->getLValue(FieldForCapture, V);
1114 
1115     SVal InitVal;
1116     if (!FieldForCapture->hasCapturedVLAType()) {
1117       Expr *InitExpr = *i;
1118       assert(InitExpr && "Capture missing initialization expression");
1119       InitVal = State->getSVal(InitExpr, LocCtxt);
1120     } else {
1121       // The field stores the length of a captured variable-length array.
1122       // These captures don't have initialization expressions; instead we
1123       // get the length from the VLAType size expression.
1124       Expr *SizeExpr = FieldForCapture->getCapturedVLAType()->getSizeExpr();
1125       InitVal = State->getSVal(SizeExpr, LocCtxt);
1126     }
1127 
1128     State = State->bindLoc(FieldLoc, InitVal, LocCtxt);
1129   }
1130 
1131   // Decay the Loc into an RValue, because there might be a
1132   // MaterializeTemporaryExpr node above this one which expects the bound value
1133   // to be an RValue.
1134   SVal LambdaRVal = State->getSVal(R);
1135 
1136   ExplodedNodeSet Tmp;
1137   StmtNodeBuilder Bldr(Pred, Tmp, *currBldrCtx);
1138   // FIXME: is this the right program point kind?
1139   Bldr.generateNode(LE, Pred,
1140                     State->BindExpr(LE, LocCtxt, LambdaRVal),
1141                     nullptr, ProgramPoint::PostLValueKind);
1142 
1143   // FIXME: Move all post/pre visits to ::Visit().
1144   getCheckerManager().runCheckersForPostStmt(Dst, Tmp, LE, *this);
1145 }
1146