1 //=-- ExprEngine.cpp - Path-Sensitive Expression-Level Dataflow ---*- C++ -*-=
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file defines a meta-engine for path-sensitive dataflow analysis that
11 //  is built on GREngine, but provides the boilerplate to execute transfer
12 //  functions and build the ExplodedGraph at the expression level.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #define DEBUG_TYPE "ExprEngine"
17 
18 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
19 #include "PrettyStackTraceLocationContext.h"
20 #include "clang/AST/CharUnits.h"
21 #include "clang/AST/ParentMap.h"
22 #include "clang/AST/StmtCXX.h"
23 #include "clang/AST/StmtObjC.h"
24 #include "clang/Basic/Builtins.h"
25 #include "clang/Basic/PrettyStackTrace.h"
26 #include "clang/Basic/SourceManager.h"
27 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
28 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
29 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
30 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
31 #include "llvm/ADT/ImmutableList.h"
32 #include "llvm/ADT/Statistic.h"
33 #include "llvm/Support/raw_ostream.h"
34 
35 #ifndef NDEBUG
36 #include "llvm/Support/GraphWriter.h"
37 #endif
38 
39 using namespace clang;
40 using namespace ento;
41 using llvm::APSInt;
42 
43 STATISTIC(NumRemoveDeadBindings,
44             "The # of times RemoveDeadBindings is called");
45 STATISTIC(NumMaxBlockCountReached,
46             "The # of aborted paths due to reaching the maximum block count in "
47             "a top level function");
48 STATISTIC(NumMaxBlockCountReachedInInlined,
49             "The # of aborted paths due to reaching the maximum block count in "
50             "an inlined function");
51 STATISTIC(NumTimesRetriedWithoutInlining,
52             "The # of times we re-evaluated a call without inlining");
53 
54 //===----------------------------------------------------------------------===//
55 // Engine construction and deletion.
56 //===----------------------------------------------------------------------===//
57 
58 ExprEngine::ExprEngine(AnalysisManager &mgr, bool gcEnabled,
59                        SetOfConstDecls *VisitedCalleesIn,
60                        FunctionSummariesTy *FS,
61                        InliningModes HowToInlineIn)
62   : AMgr(mgr),
63     AnalysisDeclContexts(mgr.getAnalysisDeclContextManager()),
64     Engine(*this, FS),
65     G(Engine.getGraph()),
66     StateMgr(getContext(), mgr.getStoreManagerCreator(),
67              mgr.getConstraintManagerCreator(), G.getAllocator(),
68              this),
69     SymMgr(StateMgr.getSymbolManager()),
70     svalBuilder(StateMgr.getSValBuilder()),
71     currStmtIdx(0), currBldrCtx(0),
72     ObjCNoRet(mgr.getASTContext()),
73     ObjCGCEnabled(gcEnabled), BR(mgr, *this),
74     VisitedCallees(VisitedCalleesIn),
75     HowToInline(HowToInlineIn)
76 {
77   unsigned TrimInterval = mgr.options.getGraphTrimInterval();
78   if (TrimInterval != 0) {
79     // Enable eager node reclaimation when constructing the ExplodedGraph.
80     G.enableNodeReclamation(TrimInterval);
81   }
82 }
83 
84 ExprEngine::~ExprEngine() {
85   BR.FlushReports();
86 }
87 
88 //===----------------------------------------------------------------------===//
89 // Utility methods.
90 //===----------------------------------------------------------------------===//
91 
92 ProgramStateRef ExprEngine::getInitialState(const LocationContext *InitLoc) {
93   ProgramStateRef state = StateMgr.getInitialState(InitLoc);
94   const Decl *D = InitLoc->getDecl();
95 
96   // Preconditions.
97   // FIXME: It would be nice if we had a more general mechanism to add
98   // such preconditions.  Some day.
99   do {
100 
101     if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
102       // Precondition: the first argument of 'main' is an integer guaranteed
103       //  to be > 0.
104       const IdentifierInfo *II = FD->getIdentifier();
105       if (!II || !(II->getName() == "main" && FD->getNumParams() > 0))
106         break;
107 
108       const ParmVarDecl *PD = FD->getParamDecl(0);
109       QualType T = PD->getType();
110       const BuiltinType *BT = dyn_cast<BuiltinType>(T);
111       if (!BT || !BT->isInteger())
112         break;
113 
114       const MemRegion *R = state->getRegion(PD, InitLoc);
115       if (!R)
116         break;
117 
118       SVal V = state->getSVal(loc::MemRegionVal(R));
119       SVal Constraint_untested = evalBinOp(state, BO_GT, V,
120                                            svalBuilder.makeZeroVal(T),
121                                            getContext().IntTy);
122 
123       Optional<DefinedOrUnknownSVal> Constraint =
124           Constraint_untested.getAs<DefinedOrUnknownSVal>();
125 
126       if (!Constraint)
127         break;
128 
129       if (ProgramStateRef newState = state->assume(*Constraint, true))
130         state = newState;
131     }
132     break;
133   }
134   while (0);
135 
136   if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
137     // Precondition: 'self' is always non-null upon entry to an Objective-C
138     // method.
139     const ImplicitParamDecl *SelfD = MD->getSelfDecl();
140     const MemRegion *R = state->getRegion(SelfD, InitLoc);
141     SVal V = state->getSVal(loc::MemRegionVal(R));
142 
143     if (Optional<Loc> LV = V.getAs<Loc>()) {
144       // Assume that the pointer value in 'self' is non-null.
145       state = state->assume(*LV, true);
146       assert(state && "'self' cannot be null");
147     }
148   }
149 
150   if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
151     if (!MD->isStatic()) {
152       // Precondition: 'this' is always non-null upon entry to the
153       // top-level function.  This is our starting assumption for
154       // analyzing an "open" program.
155       const StackFrameContext *SFC = InitLoc->getCurrentStackFrame();
156       if (SFC->getParent() == 0) {
157         loc::MemRegionVal L = svalBuilder.getCXXThis(MD, SFC);
158         SVal V = state->getSVal(L);
159         if (Optional<Loc> LV = V.getAs<Loc>()) {
160           state = state->assume(*LV, true);
161           assert(state && "'this' cannot be null");
162         }
163       }
164     }
165   }
166 
167   return state;
168 }
169 
170 ProgramStateRef
171 ExprEngine::createTemporaryRegionIfNeeded(ProgramStateRef State,
172                                           const LocationContext *LC,
173                                           const Expr *Ex,
174                                           const Expr *Result) {
175   SVal V = State->getSVal(Ex, LC);
176   if (!Result) {
177     // If we don't have an explicit result expression, we're in "if needed"
178     // mode. Only create a region if the current value is a NonLoc.
179     if (!V.getAs<NonLoc>())
180       return State;
181     Result = Ex;
182   } else {
183     // We need to create a region no matter what. For sanity, make sure we don't
184     // try to stuff a Loc into a non-pointer temporary region.
185     assert(!V.getAs<Loc>() || Loc::isLocType(Result->getType()) ||
186            Result->getType()->isMemberPointerType());
187   }
188 
189   ProgramStateManager &StateMgr = State->getStateManager();
190   MemRegionManager &MRMgr = StateMgr.getRegionManager();
191   StoreManager &StoreMgr = StateMgr.getStoreManager();
192 
193   // We need to be careful about treating a derived type's value as
194   // bindings for a base type. Unless we're creating a temporary pointer region,
195   // start by stripping and recording base casts.
196   SmallVector<const CastExpr *, 4> Casts;
197   const Expr *Inner = Ex->IgnoreParens();
198   if (!Loc::isLocType(Result->getType())) {
199     while (const CastExpr *CE = dyn_cast<CastExpr>(Inner)) {
200       if (CE->getCastKind() == CK_DerivedToBase ||
201           CE->getCastKind() == CK_UncheckedDerivedToBase)
202         Casts.push_back(CE);
203       else if (CE->getCastKind() != CK_NoOp)
204         break;
205 
206       Inner = CE->getSubExpr()->IgnoreParens();
207     }
208   }
209 
210   // Create a temporary object region for the inner expression (which may have
211   // a more derived type) and bind the value into it.
212   const TypedValueRegion *TR = NULL;
213   if (const MaterializeTemporaryExpr *MT =
214           dyn_cast<MaterializeTemporaryExpr>(Result)) {
215     StorageDuration SD = MT->getStorageDuration();
216     // If this object is bound to a reference with static storage duration, we
217     // put it in a different region to prevent "address leakage" warnings.
218     if (SD == SD_Static || SD == SD_Thread)
219         TR = MRMgr.getCXXStaticTempObjectRegion(Inner);
220   }
221   if (!TR)
222     TR = MRMgr.getCXXTempObjectRegion(Inner, LC);
223 
224   SVal Reg = loc::MemRegionVal(TR);
225 
226   if (V.isUnknown())
227     V = getSValBuilder().conjureSymbolVal(Result, LC, TR->getValueType(),
228                                           currBldrCtx->blockCount());
229   State = State->bindLoc(Reg, V);
230 
231   // Re-apply the casts (from innermost to outermost) for type sanity.
232   for (SmallVectorImpl<const CastExpr *>::reverse_iterator I = Casts.rbegin(),
233                                                            E = Casts.rend();
234        I != E; ++I) {
235     Reg = StoreMgr.evalDerivedToBase(Reg, *I);
236   }
237 
238   State = State->BindExpr(Result, LC, Reg);
239   return State;
240 }
241 
242 //===----------------------------------------------------------------------===//
243 // Top-level transfer function logic (Dispatcher).
244 //===----------------------------------------------------------------------===//
245 
246 /// evalAssume - Called by ConstraintManager. Used to call checker-specific
247 ///  logic for handling assumptions on symbolic values.
248 ProgramStateRef ExprEngine::processAssume(ProgramStateRef state,
249                                               SVal cond, bool assumption) {
250   return getCheckerManager().runCheckersForEvalAssume(state, cond, assumption);
251 }
252 
253 bool ExprEngine::wantsRegionChangeUpdate(ProgramStateRef state) {
254   return getCheckerManager().wantsRegionChangeUpdate(state);
255 }
256 
257 ProgramStateRef
258 ExprEngine::processRegionChanges(ProgramStateRef state,
259                                  const InvalidatedSymbols *invalidated,
260                                  ArrayRef<const MemRegion *> Explicits,
261                                  ArrayRef<const MemRegion *> Regions,
262                                  const CallEvent *Call) {
263   return getCheckerManager().runCheckersForRegionChanges(state, invalidated,
264                                                       Explicits, Regions, Call);
265 }
266 
267 void ExprEngine::printState(raw_ostream &Out, ProgramStateRef State,
268                             const char *NL, const char *Sep) {
269   getCheckerManager().runCheckersForPrintState(Out, State, NL, Sep);
270 }
271 
272 void ExprEngine::processEndWorklist(bool hasWorkRemaining) {
273   getCheckerManager().runCheckersForEndAnalysis(G, BR, *this);
274 }
275 
276 void ExprEngine::processCFGElement(const CFGElement E, ExplodedNode *Pred,
277                                    unsigned StmtIdx, NodeBuilderContext *Ctx) {
278   PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
279   currStmtIdx = StmtIdx;
280   currBldrCtx = Ctx;
281 
282   switch (E.getKind()) {
283     case CFGElement::Statement:
284       ProcessStmt(const_cast<Stmt*>(E.castAs<CFGStmt>().getStmt()), Pred);
285       return;
286     case CFGElement::Initializer:
287       ProcessInitializer(E.castAs<CFGInitializer>().getInitializer(), Pred);
288       return;
289     case CFGElement::AutomaticObjectDtor:
290     case CFGElement::DeleteDtor:
291     case CFGElement::BaseDtor:
292     case CFGElement::MemberDtor:
293     case CFGElement::TemporaryDtor:
294       ProcessImplicitDtor(E.castAs<CFGImplicitDtor>(), Pred);
295       return;
296   }
297 }
298 
299 static bool shouldRemoveDeadBindings(AnalysisManager &AMgr,
300                                      const CFGStmt S,
301                                      const ExplodedNode *Pred,
302                                      const LocationContext *LC) {
303 
304   // Are we never purging state values?
305   if (AMgr.options.AnalysisPurgeOpt == PurgeNone)
306     return false;
307 
308   // Is this the beginning of a basic block?
309   if (Pred->getLocation().getAs<BlockEntrance>())
310     return true;
311 
312   // Is this on a non-expression?
313   if (!isa<Expr>(S.getStmt()))
314     return true;
315 
316   // Run before processing a call.
317   if (CallEvent::isCallStmt(S.getStmt()))
318     return true;
319 
320   // Is this an expression that is consumed by another expression?  If so,
321   // postpone cleaning out the state.
322   ParentMap &PM = LC->getAnalysisDeclContext()->getParentMap();
323   return !PM.isConsumedExpr(cast<Expr>(S.getStmt()));
324 }
325 
326 void ExprEngine::removeDead(ExplodedNode *Pred, ExplodedNodeSet &Out,
327                             const Stmt *ReferenceStmt,
328                             const LocationContext *LC,
329                             const Stmt *DiagnosticStmt,
330                             ProgramPoint::Kind K) {
331   assert((K == ProgramPoint::PreStmtPurgeDeadSymbolsKind ||
332           ReferenceStmt == 0 || isa<ReturnStmt>(ReferenceStmt))
333           && "PostStmt is not generally supported by the SymbolReaper yet");
334   assert(LC && "Must pass the current (or expiring) LocationContext");
335 
336   if (!DiagnosticStmt) {
337     DiagnosticStmt = ReferenceStmt;
338     assert(DiagnosticStmt && "Required for clearing a LocationContext");
339   }
340 
341   NumRemoveDeadBindings++;
342   ProgramStateRef CleanedState = Pred->getState();
343 
344   // LC is the location context being destroyed, but SymbolReaper wants a
345   // location context that is still live. (If this is the top-level stack
346   // frame, this will be null.)
347   if (!ReferenceStmt) {
348     assert(K == ProgramPoint::PostStmtPurgeDeadSymbolsKind &&
349            "Use PostStmtPurgeDeadSymbolsKind for clearing a LocationContext");
350     LC = LC->getParent();
351   }
352 
353   const StackFrameContext *SFC = LC ? LC->getCurrentStackFrame() : 0;
354   SymbolReaper SymReaper(SFC, ReferenceStmt, SymMgr, getStoreManager());
355 
356   getCheckerManager().runCheckersForLiveSymbols(CleanedState, SymReaper);
357 
358   // Create a state in which dead bindings are removed from the environment
359   // and the store. TODO: The function should just return new env and store,
360   // not a new state.
361   CleanedState = StateMgr.removeDeadBindings(CleanedState, SFC, SymReaper);
362 
363   // Process any special transfer function for dead symbols.
364   // A tag to track convenience transitions, which can be removed at cleanup.
365   static SimpleProgramPointTag cleanupTag("ExprEngine : Clean Node");
366   if (!SymReaper.hasDeadSymbols()) {
367     // Generate a CleanedNode that has the environment and store cleaned
368     // up. Since no symbols are dead, we can optimize and not clean out
369     // the constraint manager.
370     StmtNodeBuilder Bldr(Pred, Out, *currBldrCtx);
371     Bldr.generateNode(DiagnosticStmt, Pred, CleanedState, &cleanupTag, K);
372 
373   } else {
374     // Call checkers with the non-cleaned state so that they could query the
375     // values of the soon to be dead symbols.
376     ExplodedNodeSet CheckedSet;
377     getCheckerManager().runCheckersForDeadSymbols(CheckedSet, Pred, SymReaper,
378                                                   DiagnosticStmt, *this, K);
379 
380     // For each node in CheckedSet, generate CleanedNodes that have the
381     // environment, the store, and the constraints cleaned up but have the
382     // user-supplied states as the predecessors.
383     StmtNodeBuilder Bldr(CheckedSet, Out, *currBldrCtx);
384     for (ExplodedNodeSet::const_iterator
385           I = CheckedSet.begin(), E = CheckedSet.end(); I != E; ++I) {
386       ProgramStateRef CheckerState = (*I)->getState();
387 
388       // The constraint manager has not been cleaned up yet, so clean up now.
389       CheckerState = getConstraintManager().removeDeadBindings(CheckerState,
390                                                                SymReaper);
391 
392       assert(StateMgr.haveEqualEnvironments(CheckerState, Pred->getState()) &&
393         "Checkers are not allowed to modify the Environment as a part of "
394         "checkDeadSymbols processing.");
395       assert(StateMgr.haveEqualStores(CheckerState, Pred->getState()) &&
396         "Checkers are not allowed to modify the Store as a part of "
397         "checkDeadSymbols processing.");
398 
399       // Create a state based on CleanedState with CheckerState GDM and
400       // generate a transition to that state.
401       ProgramStateRef CleanedCheckerSt =
402         StateMgr.getPersistentStateWithGDM(CleanedState, CheckerState);
403       Bldr.generateNode(DiagnosticStmt, *I, CleanedCheckerSt, &cleanupTag, K);
404     }
405   }
406 }
407 
408 void ExprEngine::ProcessStmt(const CFGStmt S,
409                              ExplodedNode *Pred) {
410   // Reclaim any unnecessary nodes in the ExplodedGraph.
411   G.reclaimRecentlyAllocatedNodes();
412 
413   const Stmt *currStmt = S.getStmt();
414   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
415                                 currStmt->getLocStart(),
416                                 "Error evaluating statement");
417 
418   // Remove dead bindings and symbols.
419   ExplodedNodeSet CleanedStates;
420   if (shouldRemoveDeadBindings(AMgr, S, Pred, Pred->getLocationContext())){
421     removeDead(Pred, CleanedStates, currStmt, Pred->getLocationContext());
422   } else
423     CleanedStates.Add(Pred);
424 
425   // Visit the statement.
426   ExplodedNodeSet Dst;
427   for (ExplodedNodeSet::iterator I = CleanedStates.begin(),
428                                  E = CleanedStates.end(); I != E; ++I) {
429     ExplodedNodeSet DstI;
430     // Visit the statement.
431     Visit(currStmt, *I, DstI);
432     Dst.insert(DstI);
433   }
434 
435   // Enqueue the new nodes onto the work list.
436   Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
437 }
438 
439 void ExprEngine::ProcessInitializer(const CFGInitializer Init,
440                                     ExplodedNode *Pred) {
441   const CXXCtorInitializer *BMI = Init.getInitializer();
442 
443   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
444                                 BMI->getSourceLocation(),
445                                 "Error evaluating initializer");
446 
447   // We don't clean up dead bindings here.
448   const StackFrameContext *stackFrame =
449                            cast<StackFrameContext>(Pred->getLocationContext());
450   const CXXConstructorDecl *decl =
451                            cast<CXXConstructorDecl>(stackFrame->getDecl());
452 
453   ProgramStateRef State = Pred->getState();
454   SVal thisVal = State->getSVal(svalBuilder.getCXXThis(decl, stackFrame));
455 
456   ExplodedNodeSet Tmp(Pred);
457   SVal FieldLoc;
458 
459   // Evaluate the initializer, if necessary
460   if (BMI->isAnyMemberInitializer()) {
461     // Constructors build the object directly in the field,
462     // but non-objects must be copied in from the initializer.
463     const Expr *Init = BMI->getInit()->IgnoreImplicit();
464     if (!isa<CXXConstructExpr>(Init)) {
465       const ValueDecl *Field;
466       if (BMI->isIndirectMemberInitializer()) {
467         Field = BMI->getIndirectMember();
468         FieldLoc = State->getLValue(BMI->getIndirectMember(), thisVal);
469       } else {
470         Field = BMI->getMember();
471         FieldLoc = State->getLValue(BMI->getMember(), thisVal);
472       }
473 
474       SVal InitVal;
475       if (BMI->getNumArrayIndices() > 0) {
476         // Handle arrays of trivial type. We can represent this with a
477         // primitive load/copy from the base array region.
478         const ArraySubscriptExpr *ASE;
479         while ((ASE = dyn_cast<ArraySubscriptExpr>(Init)))
480           Init = ASE->getBase()->IgnoreImplicit();
481 
482         SVal LValue = State->getSVal(Init, stackFrame);
483         if (Optional<Loc> LValueLoc = LValue.getAs<Loc>())
484           InitVal = State->getSVal(*LValueLoc);
485 
486         // If we fail to get the value for some reason, use a symbolic value.
487         if (InitVal.isUnknownOrUndef()) {
488           SValBuilder &SVB = getSValBuilder();
489           InitVal = SVB.conjureSymbolVal(BMI->getInit(), stackFrame,
490                                          Field->getType(),
491                                          currBldrCtx->blockCount());
492         }
493       } else {
494         InitVal = State->getSVal(BMI->getInit(), stackFrame);
495       }
496 
497       assert(Tmp.size() == 1 && "have not generated any new nodes yet");
498       assert(*Tmp.begin() == Pred && "have not generated any new nodes yet");
499       Tmp.clear();
500 
501       PostInitializer PP(BMI, FieldLoc.getAsRegion(), stackFrame);
502       evalBind(Tmp, Init, Pred, FieldLoc, InitVal, /*isInit=*/true, &PP);
503     }
504   } else {
505     assert(BMI->isBaseInitializer() || BMI->isDelegatingInitializer());
506     // We already did all the work when visiting the CXXConstructExpr.
507   }
508 
509   // Construct PostInitializer nodes whether the state changed or not,
510   // so that the diagnostics don't get confused.
511   PostInitializer PP(BMI, FieldLoc.getAsRegion(), stackFrame);
512   ExplodedNodeSet Dst;
513   NodeBuilder Bldr(Tmp, Dst, *currBldrCtx);
514   for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I != E; ++I) {
515     ExplodedNode *N = *I;
516     Bldr.generateNode(PP, N->getState(), N);
517   }
518 
519   // Enqueue the new nodes onto the work list.
520   Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
521 }
522 
523 void ExprEngine::ProcessImplicitDtor(const CFGImplicitDtor D,
524                                      ExplodedNode *Pred) {
525   ExplodedNodeSet Dst;
526   switch (D.getKind()) {
527   case CFGElement::AutomaticObjectDtor:
528     ProcessAutomaticObjDtor(D.castAs<CFGAutomaticObjDtor>(), Pred, Dst);
529     break;
530   case CFGElement::BaseDtor:
531     ProcessBaseDtor(D.castAs<CFGBaseDtor>(), Pred, Dst);
532     break;
533   case CFGElement::MemberDtor:
534     ProcessMemberDtor(D.castAs<CFGMemberDtor>(), Pred, Dst);
535     break;
536   case CFGElement::TemporaryDtor:
537     ProcessTemporaryDtor(D.castAs<CFGTemporaryDtor>(), Pred, Dst);
538     break;
539   case CFGElement::DeleteDtor:
540     ProcessDeleteDtor(D.castAs<CFGDeleteDtor>(), Pred, Dst);
541     break;
542   default:
543     llvm_unreachable("Unexpected dtor kind.");
544   }
545 
546   // Enqueue the new nodes onto the work list.
547   Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
548 }
549 
550 void ExprEngine::ProcessAutomaticObjDtor(const CFGAutomaticObjDtor Dtor,
551                                          ExplodedNode *Pred,
552                                          ExplodedNodeSet &Dst) {
553   const VarDecl *varDecl = Dtor.getVarDecl();
554   QualType varType = varDecl->getType();
555 
556   ProgramStateRef state = Pred->getState();
557   SVal dest = state->getLValue(varDecl, Pred->getLocationContext());
558   const MemRegion *Region = dest.castAs<loc::MemRegionVal>().getRegion();
559 
560   if (const ReferenceType *refType = varType->getAs<ReferenceType>()) {
561     varType = refType->getPointeeType();
562     Region = state->getSVal(Region).getAsRegion();
563   }
564 
565   VisitCXXDestructor(varType, Region, Dtor.getTriggerStmt(), /*IsBase=*/ false,
566                      Pred, Dst);
567 }
568 
569 void ExprEngine::ProcessDeleteDtor(const CFGDeleteDtor Dtor,
570                                    ExplodedNode *Pred,
571                                    ExplodedNodeSet &Dst) {
572   //TODO: Handle DeleteDtor
573 }
574 
575 void ExprEngine::ProcessBaseDtor(const CFGBaseDtor D,
576                                  ExplodedNode *Pred, ExplodedNodeSet &Dst) {
577   const LocationContext *LCtx = Pred->getLocationContext();
578   ProgramStateRef State = Pred->getState();
579 
580   const CXXDestructorDecl *CurDtor = cast<CXXDestructorDecl>(LCtx->getDecl());
581   Loc ThisPtr = getSValBuilder().getCXXThis(CurDtor,
582                                             LCtx->getCurrentStackFrame());
583   SVal ThisVal = Pred->getState()->getSVal(ThisPtr);
584 
585   // Create the base object region.
586   const CXXBaseSpecifier *Base = D.getBaseSpecifier();
587   QualType BaseTy = Base->getType();
588   SVal BaseVal = getStoreManager().evalDerivedToBase(ThisVal, BaseTy,
589                                                      Base->isVirtual());
590 
591   VisitCXXDestructor(BaseTy, BaseVal.castAs<loc::MemRegionVal>().getRegion(),
592                      CurDtor->getBody(), /*IsBase=*/ true, Pred, Dst);
593 }
594 
595 void ExprEngine::ProcessMemberDtor(const CFGMemberDtor D,
596                                    ExplodedNode *Pred, ExplodedNodeSet &Dst) {
597   const FieldDecl *Member = D.getFieldDecl();
598   ProgramStateRef State = Pred->getState();
599   const LocationContext *LCtx = Pred->getLocationContext();
600 
601   const CXXDestructorDecl *CurDtor = cast<CXXDestructorDecl>(LCtx->getDecl());
602   Loc ThisVal = getSValBuilder().getCXXThis(CurDtor,
603                                             LCtx->getCurrentStackFrame());
604   SVal FieldVal =
605       State->getLValue(Member, State->getSVal(ThisVal).castAs<Loc>());
606 
607   VisitCXXDestructor(Member->getType(),
608                      FieldVal.castAs<loc::MemRegionVal>().getRegion(),
609                      CurDtor->getBody(), /*IsBase=*/false, Pred, Dst);
610 }
611 
612 void ExprEngine::ProcessTemporaryDtor(const CFGTemporaryDtor D,
613                                       ExplodedNode *Pred,
614                                       ExplodedNodeSet &Dst) {
615 
616   QualType varType = D.getBindTemporaryExpr()->getSubExpr()->getType();
617 
618   // FIXME: Inlining of temporary destructors is not supported yet anyway, so we
619   // just put a NULL region for now. This will need to be changed later.
620   VisitCXXDestructor(varType, NULL, D.getBindTemporaryExpr(),
621                      /*IsBase=*/ false, Pred, Dst);
622 }
623 
624 void ExprEngine::Visit(const Stmt *S, ExplodedNode *Pred,
625                        ExplodedNodeSet &DstTop) {
626   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
627                                 S->getLocStart(),
628                                 "Error evaluating statement");
629   ExplodedNodeSet Dst;
630   StmtNodeBuilder Bldr(Pred, DstTop, *currBldrCtx);
631 
632   assert(!isa<Expr>(S) || S == cast<Expr>(S)->IgnoreParens());
633 
634   switch (S->getStmtClass()) {
635     // C++ and ARC stuff we don't support yet.
636     case Expr::ObjCIndirectCopyRestoreExprClass:
637     case Stmt::CXXDependentScopeMemberExprClass:
638     case Stmt::CXXTryStmtClass:
639     case Stmt::CXXTypeidExprClass:
640     case Stmt::CXXUuidofExprClass:
641     case Stmt::MSPropertyRefExprClass:
642     case Stmt::CXXUnresolvedConstructExprClass:
643     case Stmt::DependentScopeDeclRefExprClass:
644     case Stmt::UnaryTypeTraitExprClass:
645     case Stmt::BinaryTypeTraitExprClass:
646     case Stmt::TypeTraitExprClass:
647     case Stmt::ArrayTypeTraitExprClass:
648     case Stmt::ExpressionTraitExprClass:
649     case Stmt::UnresolvedLookupExprClass:
650     case Stmt::UnresolvedMemberExprClass:
651     case Stmt::CXXNoexceptExprClass:
652     case Stmt::PackExpansionExprClass:
653     case Stmt::SubstNonTypeTemplateParmPackExprClass:
654     case Stmt::FunctionParmPackExprClass:
655     case Stmt::SEHTryStmtClass:
656     case Stmt::SEHExceptStmtClass:
657     case Stmt::LambdaExprClass:
658     case Stmt::SEHFinallyStmtClass: {
659       const ExplodedNode *node = Bldr.generateSink(S, Pred, Pred->getState());
660       Engine.addAbortedBlock(node, currBldrCtx->getBlock());
661       break;
662     }
663 
664     case Stmt::ParenExprClass:
665       llvm_unreachable("ParenExprs already handled.");
666     case Stmt::GenericSelectionExprClass:
667       llvm_unreachable("GenericSelectionExprs already handled.");
668     // Cases that should never be evaluated simply because they shouldn't
669     // appear in the CFG.
670     case Stmt::BreakStmtClass:
671     case Stmt::CaseStmtClass:
672     case Stmt::CompoundStmtClass:
673     case Stmt::ContinueStmtClass:
674     case Stmt::CXXForRangeStmtClass:
675     case Stmt::DefaultStmtClass:
676     case Stmt::DoStmtClass:
677     case Stmt::ForStmtClass:
678     case Stmt::GotoStmtClass:
679     case Stmt::IfStmtClass:
680     case Stmt::IndirectGotoStmtClass:
681     case Stmt::LabelStmtClass:
682     case Stmt::NoStmtClass:
683     case Stmt::NullStmtClass:
684     case Stmt::SwitchStmtClass:
685     case Stmt::WhileStmtClass:
686     case Expr::MSDependentExistsStmtClass:
687     case Stmt::CapturedStmtClass:
688     case Stmt::OMPParallelDirectiveClass:
689       llvm_unreachable("Stmt should not be in analyzer evaluation loop");
690 
691     case Stmt::ObjCSubscriptRefExprClass:
692     case Stmt::ObjCPropertyRefExprClass:
693       llvm_unreachable("These are handled by PseudoObjectExpr");
694 
695     case Stmt::GNUNullExprClass: {
696       // GNU __null is a pointer-width integer, not an actual pointer.
697       ProgramStateRef state = Pred->getState();
698       state = state->BindExpr(S, Pred->getLocationContext(),
699                               svalBuilder.makeIntValWithPtrWidth(0, false));
700       Bldr.generateNode(S, Pred, state);
701       break;
702     }
703 
704     case Stmt::ObjCAtSynchronizedStmtClass:
705       Bldr.takeNodes(Pred);
706       VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S), Pred, Dst);
707       Bldr.addNodes(Dst);
708       break;
709 
710     case Stmt::ExprWithCleanupsClass:
711       // Handled due to fully linearised CFG.
712       break;
713 
714     // Cases not handled yet; but will handle some day.
715     case Stmt::DesignatedInitExprClass:
716     case Stmt::ExtVectorElementExprClass:
717     case Stmt::ImaginaryLiteralClass:
718     case Stmt::ObjCAtCatchStmtClass:
719     case Stmt::ObjCAtFinallyStmtClass:
720     case Stmt::ObjCAtTryStmtClass:
721     case Stmt::ObjCAutoreleasePoolStmtClass:
722     case Stmt::ObjCEncodeExprClass:
723     case Stmt::ObjCIsaExprClass:
724     case Stmt::ObjCProtocolExprClass:
725     case Stmt::ObjCSelectorExprClass:
726     case Stmt::ParenListExprClass:
727     case Stmt::PredefinedExprClass:
728     case Stmt::ShuffleVectorExprClass:
729     case Stmt::VAArgExprClass:
730     case Stmt::CUDAKernelCallExprClass:
731     case Stmt::OpaqueValueExprClass:
732     case Stmt::AsTypeExprClass:
733     case Stmt::AtomicExprClass:
734       // Fall through.
735 
736     // Cases we intentionally don't evaluate, since they don't need
737     // to be explicitly evaluated.
738     case Stmt::AddrLabelExprClass:
739     case Stmt::AttributedStmtClass:
740     case Stmt::IntegerLiteralClass:
741     case Stmt::CharacterLiteralClass:
742     case Stmt::ImplicitValueInitExprClass:
743     case Stmt::CXXScalarValueInitExprClass:
744     case Stmt::CXXBoolLiteralExprClass:
745     case Stmt::ObjCBoolLiteralExprClass:
746     case Stmt::FloatingLiteralClass:
747     case Stmt::SizeOfPackExprClass:
748     case Stmt::StringLiteralClass:
749     case Stmt::ObjCStringLiteralClass:
750     case Stmt::CXXBindTemporaryExprClass:
751     case Stmt::CXXPseudoDestructorExprClass:
752     case Stmt::SubstNonTypeTemplateParmExprClass:
753     case Stmt::CXXNullPtrLiteralExprClass: {
754       Bldr.takeNodes(Pred);
755       ExplodedNodeSet preVisit;
756       getCheckerManager().runCheckersForPreStmt(preVisit, Pred, S, *this);
757       getCheckerManager().runCheckersForPostStmt(Dst, preVisit, S, *this);
758       Bldr.addNodes(Dst);
759       break;
760     }
761 
762     case Stmt::CXXDefaultArgExprClass:
763     case Stmt::CXXDefaultInitExprClass: {
764       Bldr.takeNodes(Pred);
765       ExplodedNodeSet PreVisit;
766       getCheckerManager().runCheckersForPreStmt(PreVisit, Pred, S, *this);
767 
768       ExplodedNodeSet Tmp;
769       StmtNodeBuilder Bldr2(PreVisit, Tmp, *currBldrCtx);
770 
771       const Expr *ArgE;
772       if (const CXXDefaultArgExpr *DefE = dyn_cast<CXXDefaultArgExpr>(S))
773         ArgE = DefE->getExpr();
774       else if (const CXXDefaultInitExpr *DefE = dyn_cast<CXXDefaultInitExpr>(S))
775         ArgE = DefE->getExpr();
776       else
777         llvm_unreachable("unknown constant wrapper kind");
778 
779       bool IsTemporary = false;
780       if (const MaterializeTemporaryExpr *MTE =
781             dyn_cast<MaterializeTemporaryExpr>(ArgE)) {
782         ArgE = MTE->GetTemporaryExpr();
783         IsTemporary = true;
784       }
785 
786       Optional<SVal> ConstantVal = svalBuilder.getConstantVal(ArgE);
787       if (!ConstantVal)
788         ConstantVal = UnknownVal();
789 
790       const LocationContext *LCtx = Pred->getLocationContext();
791       for (ExplodedNodeSet::iterator I = PreVisit.begin(), E = PreVisit.end();
792            I != E; ++I) {
793         ProgramStateRef State = (*I)->getState();
794         State = State->BindExpr(S, LCtx, *ConstantVal);
795         if (IsTemporary)
796           State = createTemporaryRegionIfNeeded(State, LCtx,
797                                                 cast<Expr>(S),
798                                                 cast<Expr>(S));
799         Bldr2.generateNode(S, *I, State);
800       }
801 
802       getCheckerManager().runCheckersForPostStmt(Dst, Tmp, S, *this);
803       Bldr.addNodes(Dst);
804       break;
805     }
806 
807     // Cases we evaluate as opaque expressions, conjuring a symbol.
808     case Stmt::CXXStdInitializerListExprClass:
809     case Expr::ObjCArrayLiteralClass:
810     case Expr::ObjCDictionaryLiteralClass:
811     case Expr::ObjCBoxedExprClass: {
812       Bldr.takeNodes(Pred);
813 
814       ExplodedNodeSet preVisit;
815       getCheckerManager().runCheckersForPreStmt(preVisit, Pred, S, *this);
816 
817       ExplodedNodeSet Tmp;
818       StmtNodeBuilder Bldr2(preVisit, Tmp, *currBldrCtx);
819 
820       const Expr *Ex = cast<Expr>(S);
821       QualType resultType = Ex->getType();
822 
823       for (ExplodedNodeSet::iterator it = preVisit.begin(), et = preVisit.end();
824            it != et; ++it) {
825         ExplodedNode *N = *it;
826         const LocationContext *LCtx = N->getLocationContext();
827         SVal result = svalBuilder.conjureSymbolVal(0, Ex, LCtx, resultType,
828                                                    currBldrCtx->blockCount());
829         ProgramStateRef state = N->getState()->BindExpr(Ex, LCtx, result);
830         Bldr2.generateNode(S, N, state);
831       }
832 
833       getCheckerManager().runCheckersForPostStmt(Dst, Tmp, S, *this);
834       Bldr.addNodes(Dst);
835       break;
836     }
837 
838     case Stmt::ArraySubscriptExprClass:
839       Bldr.takeNodes(Pred);
840       VisitLvalArraySubscriptExpr(cast<ArraySubscriptExpr>(S), Pred, Dst);
841       Bldr.addNodes(Dst);
842       break;
843 
844     case Stmt::GCCAsmStmtClass:
845       Bldr.takeNodes(Pred);
846       VisitGCCAsmStmt(cast<GCCAsmStmt>(S), Pred, Dst);
847       Bldr.addNodes(Dst);
848       break;
849 
850     case Stmt::MSAsmStmtClass:
851       Bldr.takeNodes(Pred);
852       VisitMSAsmStmt(cast<MSAsmStmt>(S), Pred, Dst);
853       Bldr.addNodes(Dst);
854       break;
855 
856     case Stmt::BlockExprClass:
857       Bldr.takeNodes(Pred);
858       VisitBlockExpr(cast<BlockExpr>(S), Pred, Dst);
859       Bldr.addNodes(Dst);
860       break;
861 
862     case Stmt::BinaryOperatorClass: {
863       const BinaryOperator* B = cast<BinaryOperator>(S);
864       if (B->isLogicalOp()) {
865         Bldr.takeNodes(Pred);
866         VisitLogicalExpr(B, Pred, Dst);
867         Bldr.addNodes(Dst);
868         break;
869       }
870       else if (B->getOpcode() == BO_Comma) {
871         ProgramStateRef state = Pred->getState();
872         Bldr.generateNode(B, Pred,
873                           state->BindExpr(B, Pred->getLocationContext(),
874                                           state->getSVal(B->getRHS(),
875                                                   Pred->getLocationContext())));
876         break;
877       }
878 
879       Bldr.takeNodes(Pred);
880 
881       if (AMgr.options.eagerlyAssumeBinOpBifurcation &&
882           (B->isRelationalOp() || B->isEqualityOp())) {
883         ExplodedNodeSet Tmp;
884         VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Tmp);
885         evalEagerlyAssumeBinOpBifurcation(Dst, Tmp, cast<Expr>(S));
886       }
887       else
888         VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Dst);
889 
890       Bldr.addNodes(Dst);
891       break;
892     }
893 
894     case Stmt::CXXOperatorCallExprClass: {
895       const CXXOperatorCallExpr *OCE = cast<CXXOperatorCallExpr>(S);
896 
897       // For instance method operators, make sure the 'this' argument has a
898       // valid region.
899       const Decl *Callee = OCE->getCalleeDecl();
900       if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(Callee)) {
901         if (MD->isInstance()) {
902           ProgramStateRef State = Pred->getState();
903           const LocationContext *LCtx = Pred->getLocationContext();
904           ProgramStateRef NewState =
905             createTemporaryRegionIfNeeded(State, LCtx, OCE->getArg(0));
906           if (NewState != State) {
907             Pred = Bldr.generateNode(OCE, Pred, NewState, /*Tag=*/0,
908                                      ProgramPoint::PreStmtKind);
909             // Did we cache out?
910             if (!Pred)
911               break;
912           }
913         }
914       }
915       // FALLTHROUGH
916     }
917     case Stmt::CallExprClass:
918     case Stmt::CXXMemberCallExprClass:
919     case Stmt::UserDefinedLiteralClass: {
920       Bldr.takeNodes(Pred);
921       VisitCallExpr(cast<CallExpr>(S), Pred, Dst);
922       Bldr.addNodes(Dst);
923       break;
924     }
925 
926     case Stmt::CXXCatchStmtClass: {
927       Bldr.takeNodes(Pred);
928       VisitCXXCatchStmt(cast<CXXCatchStmt>(S), Pred, Dst);
929       Bldr.addNodes(Dst);
930       break;
931     }
932 
933     case Stmt::CXXTemporaryObjectExprClass:
934     case Stmt::CXXConstructExprClass: {
935       Bldr.takeNodes(Pred);
936       VisitCXXConstructExpr(cast<CXXConstructExpr>(S), Pred, Dst);
937       Bldr.addNodes(Dst);
938       break;
939     }
940 
941     case Stmt::CXXNewExprClass: {
942       Bldr.takeNodes(Pred);
943       ExplodedNodeSet PostVisit;
944       VisitCXXNewExpr(cast<CXXNewExpr>(S), Pred, PostVisit);
945       getCheckerManager().runCheckersForPostStmt(Dst, PostVisit, S, *this);
946       Bldr.addNodes(Dst);
947       break;
948     }
949 
950     case Stmt::CXXDeleteExprClass: {
951       Bldr.takeNodes(Pred);
952       ExplodedNodeSet PreVisit;
953       const CXXDeleteExpr *CDE = cast<CXXDeleteExpr>(S);
954       getCheckerManager().runCheckersForPreStmt(PreVisit, Pred, S, *this);
955 
956       for (ExplodedNodeSet::iterator i = PreVisit.begin(),
957                                      e = PreVisit.end(); i != e ; ++i)
958         VisitCXXDeleteExpr(CDE, *i, Dst);
959 
960       Bldr.addNodes(Dst);
961       break;
962     }
963       // FIXME: ChooseExpr is really a constant.  We need to fix
964       //        the CFG do not model them as explicit control-flow.
965 
966     case Stmt::ChooseExprClass: { // __builtin_choose_expr
967       Bldr.takeNodes(Pred);
968       const ChooseExpr *C = cast<ChooseExpr>(S);
969       VisitGuardedExpr(C, C->getLHS(), C->getRHS(), Pred, Dst);
970       Bldr.addNodes(Dst);
971       break;
972     }
973 
974     case Stmt::CompoundAssignOperatorClass:
975       Bldr.takeNodes(Pred);
976       VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Dst);
977       Bldr.addNodes(Dst);
978       break;
979 
980     case Stmt::CompoundLiteralExprClass:
981       Bldr.takeNodes(Pred);
982       VisitCompoundLiteralExpr(cast<CompoundLiteralExpr>(S), Pred, Dst);
983       Bldr.addNodes(Dst);
984       break;
985 
986     case Stmt::BinaryConditionalOperatorClass:
987     case Stmt::ConditionalOperatorClass: { // '?' operator
988       Bldr.takeNodes(Pred);
989       const AbstractConditionalOperator *C
990         = cast<AbstractConditionalOperator>(S);
991       VisitGuardedExpr(C, C->getTrueExpr(), C->getFalseExpr(), Pred, Dst);
992       Bldr.addNodes(Dst);
993       break;
994     }
995 
996     case Stmt::CXXThisExprClass:
997       Bldr.takeNodes(Pred);
998       VisitCXXThisExpr(cast<CXXThisExpr>(S), Pred, Dst);
999       Bldr.addNodes(Dst);
1000       break;
1001 
1002     case Stmt::DeclRefExprClass: {
1003       Bldr.takeNodes(Pred);
1004       const DeclRefExpr *DE = cast<DeclRefExpr>(S);
1005       VisitCommonDeclRefExpr(DE, DE->getDecl(), Pred, Dst);
1006       Bldr.addNodes(Dst);
1007       break;
1008     }
1009 
1010     case Stmt::DeclStmtClass:
1011       Bldr.takeNodes(Pred);
1012       VisitDeclStmt(cast<DeclStmt>(S), Pred, Dst);
1013       Bldr.addNodes(Dst);
1014       break;
1015 
1016     case Stmt::ImplicitCastExprClass:
1017     case Stmt::CStyleCastExprClass:
1018     case Stmt::CXXStaticCastExprClass:
1019     case Stmt::CXXDynamicCastExprClass:
1020     case Stmt::CXXReinterpretCastExprClass:
1021     case Stmt::CXXConstCastExprClass:
1022     case Stmt::CXXFunctionalCastExprClass:
1023     case Stmt::ObjCBridgedCastExprClass: {
1024       Bldr.takeNodes(Pred);
1025       const CastExpr *C = cast<CastExpr>(S);
1026       // Handle the previsit checks.
1027       ExplodedNodeSet dstPrevisit;
1028       getCheckerManager().runCheckersForPreStmt(dstPrevisit, Pred, C, *this);
1029 
1030       // Handle the expression itself.
1031       ExplodedNodeSet dstExpr;
1032       for (ExplodedNodeSet::iterator i = dstPrevisit.begin(),
1033                                      e = dstPrevisit.end(); i != e ; ++i) {
1034         VisitCast(C, C->getSubExpr(), *i, dstExpr);
1035       }
1036 
1037       // Handle the postvisit checks.
1038       getCheckerManager().runCheckersForPostStmt(Dst, dstExpr, C, *this);
1039       Bldr.addNodes(Dst);
1040       break;
1041     }
1042 
1043     case Expr::MaterializeTemporaryExprClass: {
1044       Bldr.takeNodes(Pred);
1045       const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(S);
1046       CreateCXXTemporaryObject(MTE, Pred, Dst);
1047       Bldr.addNodes(Dst);
1048       break;
1049     }
1050 
1051     case Stmt::InitListExprClass:
1052       Bldr.takeNodes(Pred);
1053       VisitInitListExpr(cast<InitListExpr>(S), Pred, Dst);
1054       Bldr.addNodes(Dst);
1055       break;
1056 
1057     case Stmt::MemberExprClass:
1058       Bldr.takeNodes(Pred);
1059       VisitMemberExpr(cast<MemberExpr>(S), Pred, Dst);
1060       Bldr.addNodes(Dst);
1061       break;
1062 
1063     case Stmt::ObjCIvarRefExprClass:
1064       Bldr.takeNodes(Pred);
1065       VisitLvalObjCIvarRefExpr(cast<ObjCIvarRefExpr>(S), Pred, Dst);
1066       Bldr.addNodes(Dst);
1067       break;
1068 
1069     case Stmt::ObjCForCollectionStmtClass:
1070       Bldr.takeNodes(Pred);
1071       VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S), Pred, Dst);
1072       Bldr.addNodes(Dst);
1073       break;
1074 
1075     case Stmt::ObjCMessageExprClass:
1076       Bldr.takeNodes(Pred);
1077       VisitObjCMessage(cast<ObjCMessageExpr>(S), Pred, Dst);
1078       Bldr.addNodes(Dst);
1079       break;
1080 
1081     case Stmt::ObjCAtThrowStmtClass:
1082     case Stmt::CXXThrowExprClass:
1083       // FIXME: This is not complete.  We basically treat @throw as
1084       // an abort.
1085       Bldr.generateSink(S, Pred, Pred->getState());
1086       break;
1087 
1088     case Stmt::ReturnStmtClass:
1089       Bldr.takeNodes(Pred);
1090       VisitReturnStmt(cast<ReturnStmt>(S), Pred, Dst);
1091       Bldr.addNodes(Dst);
1092       break;
1093 
1094     case Stmt::OffsetOfExprClass:
1095       Bldr.takeNodes(Pred);
1096       VisitOffsetOfExpr(cast<OffsetOfExpr>(S), Pred, Dst);
1097       Bldr.addNodes(Dst);
1098       break;
1099 
1100     case Stmt::UnaryExprOrTypeTraitExprClass:
1101       Bldr.takeNodes(Pred);
1102       VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
1103                                     Pred, Dst);
1104       Bldr.addNodes(Dst);
1105       break;
1106 
1107     case Stmt::StmtExprClass: {
1108       const StmtExpr *SE = cast<StmtExpr>(S);
1109 
1110       if (SE->getSubStmt()->body_empty()) {
1111         // Empty statement expression.
1112         assert(SE->getType() == getContext().VoidTy
1113                && "Empty statement expression must have void type.");
1114         break;
1115       }
1116 
1117       if (Expr *LastExpr = dyn_cast<Expr>(*SE->getSubStmt()->body_rbegin())) {
1118         ProgramStateRef state = Pred->getState();
1119         Bldr.generateNode(SE, Pred,
1120                           state->BindExpr(SE, Pred->getLocationContext(),
1121                                           state->getSVal(LastExpr,
1122                                                   Pred->getLocationContext())));
1123       }
1124       break;
1125     }
1126 
1127     case Stmt::UnaryOperatorClass: {
1128       Bldr.takeNodes(Pred);
1129       const UnaryOperator *U = cast<UnaryOperator>(S);
1130       if (AMgr.options.eagerlyAssumeBinOpBifurcation && (U->getOpcode() == UO_LNot)) {
1131         ExplodedNodeSet Tmp;
1132         VisitUnaryOperator(U, Pred, Tmp);
1133         evalEagerlyAssumeBinOpBifurcation(Dst, Tmp, U);
1134       }
1135       else
1136         VisitUnaryOperator(U, Pred, Dst);
1137       Bldr.addNodes(Dst);
1138       break;
1139     }
1140 
1141     case Stmt::PseudoObjectExprClass: {
1142       Bldr.takeNodes(Pred);
1143       ProgramStateRef state = Pred->getState();
1144       const PseudoObjectExpr *PE = cast<PseudoObjectExpr>(S);
1145       if (const Expr *Result = PE->getResultExpr()) {
1146         SVal V = state->getSVal(Result, Pred->getLocationContext());
1147         Bldr.generateNode(S, Pred,
1148                           state->BindExpr(S, Pred->getLocationContext(), V));
1149       }
1150       else
1151         Bldr.generateNode(S, Pred,
1152                           state->BindExpr(S, Pred->getLocationContext(),
1153                                                    UnknownVal()));
1154 
1155       Bldr.addNodes(Dst);
1156       break;
1157     }
1158   }
1159 }
1160 
1161 bool ExprEngine::replayWithoutInlining(ExplodedNode *N,
1162                                        const LocationContext *CalleeLC) {
1163   const StackFrameContext *CalleeSF = CalleeLC->getCurrentStackFrame();
1164   const StackFrameContext *CallerSF = CalleeSF->getParent()->getCurrentStackFrame();
1165   assert(CalleeSF && CallerSF);
1166   ExplodedNode *BeforeProcessingCall = 0;
1167   const Stmt *CE = CalleeSF->getCallSite();
1168 
1169   // Find the first node before we started processing the call expression.
1170   while (N) {
1171     ProgramPoint L = N->getLocation();
1172     BeforeProcessingCall = N;
1173     N = N->pred_empty() ? NULL : *(N->pred_begin());
1174 
1175     // Skip the nodes corresponding to the inlined code.
1176     if (L.getLocationContext()->getCurrentStackFrame() != CallerSF)
1177       continue;
1178     // We reached the caller. Find the node right before we started
1179     // processing the call.
1180     if (L.isPurgeKind())
1181       continue;
1182     if (L.getAs<PreImplicitCall>())
1183       continue;
1184     if (L.getAs<CallEnter>())
1185       continue;
1186     if (Optional<StmtPoint> SP = L.getAs<StmtPoint>())
1187       if (SP->getStmt() == CE)
1188         continue;
1189     break;
1190   }
1191 
1192   if (!BeforeProcessingCall)
1193     return false;
1194 
1195   // TODO: Clean up the unneeded nodes.
1196 
1197   // Build an Epsilon node from which we will restart the analyzes.
1198   // Note that CE is permitted to be NULL!
1199   ProgramPoint NewNodeLoc =
1200                EpsilonPoint(BeforeProcessingCall->getLocationContext(), CE);
1201   // Add the special flag to GDM to signal retrying with no inlining.
1202   // Note, changing the state ensures that we are not going to cache out.
1203   ProgramStateRef NewNodeState = BeforeProcessingCall->getState();
1204   NewNodeState =
1205     NewNodeState->set<ReplayWithoutInlining>(const_cast<Stmt *>(CE));
1206 
1207   // Make the new node a successor of BeforeProcessingCall.
1208   bool IsNew = false;
1209   ExplodedNode *NewNode = G.getNode(NewNodeLoc, NewNodeState, false, &IsNew);
1210   // We cached out at this point. Caching out is common due to us backtracking
1211   // from the inlined function, which might spawn several paths.
1212   if (!IsNew)
1213     return true;
1214 
1215   NewNode->addPredecessor(BeforeProcessingCall, G);
1216 
1217   // Add the new node to the work list.
1218   Engine.enqueueStmtNode(NewNode, CalleeSF->getCallSiteBlock(),
1219                                   CalleeSF->getIndex());
1220   NumTimesRetriedWithoutInlining++;
1221   return true;
1222 }
1223 
1224 /// Block entrance.  (Update counters).
1225 void ExprEngine::processCFGBlockEntrance(const BlockEdge &L,
1226                                          NodeBuilderWithSinks &nodeBuilder,
1227                                          ExplodedNode *Pred) {
1228   PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
1229 
1230   // FIXME: Refactor this into a checker.
1231   if (nodeBuilder.getContext().blockCount() >= AMgr.options.maxBlockVisitOnPath) {
1232     static SimpleProgramPointTag tag("ExprEngine : Block count exceeded");
1233     const ExplodedNode *Sink =
1234                    nodeBuilder.generateSink(Pred->getState(), Pred, &tag);
1235 
1236     // Check if we stopped at the top level function or not.
1237     // Root node should have the location context of the top most function.
1238     const LocationContext *CalleeLC = Pred->getLocation().getLocationContext();
1239     const LocationContext *CalleeSF = CalleeLC->getCurrentStackFrame();
1240     const LocationContext *RootLC =
1241                         (*G.roots_begin())->getLocation().getLocationContext();
1242     if (RootLC->getCurrentStackFrame() != CalleeSF) {
1243       Engine.FunctionSummaries->markReachedMaxBlockCount(CalleeSF->getDecl());
1244 
1245       // Re-run the call evaluation without inlining it, by storing the
1246       // no-inlining policy in the state and enqueuing the new work item on
1247       // the list. Replay should almost never fail. Use the stats to catch it
1248       // if it does.
1249       if ((!AMgr.options.NoRetryExhausted &&
1250            replayWithoutInlining(Pred, CalleeLC)))
1251         return;
1252       NumMaxBlockCountReachedInInlined++;
1253     } else
1254       NumMaxBlockCountReached++;
1255 
1256     // Make sink nodes as exhausted(for stats) only if retry failed.
1257     Engine.blocksExhausted.push_back(std::make_pair(L, Sink));
1258   }
1259 }
1260 
1261 //===----------------------------------------------------------------------===//
1262 // Branch processing.
1263 //===----------------------------------------------------------------------===//
1264 
1265 /// RecoverCastedSymbol - A helper function for ProcessBranch that is used
1266 /// to try to recover some path-sensitivity for casts of symbolic
1267 /// integers that promote their values (which are currently not tracked well).
1268 /// This function returns the SVal bound to Condition->IgnoreCasts if all the
1269 //  cast(s) did was sign-extend the original value.
1270 static SVal RecoverCastedSymbol(ProgramStateManager& StateMgr,
1271                                 ProgramStateRef state,
1272                                 const Stmt *Condition,
1273                                 const LocationContext *LCtx,
1274                                 ASTContext &Ctx) {
1275 
1276   const Expr *Ex = dyn_cast<Expr>(Condition);
1277   if (!Ex)
1278     return UnknownVal();
1279 
1280   uint64_t bits = 0;
1281   bool bitsInit = false;
1282 
1283   while (const CastExpr *CE = dyn_cast<CastExpr>(Ex)) {
1284     QualType T = CE->getType();
1285 
1286     if (!T->isIntegralOrEnumerationType())
1287       return UnknownVal();
1288 
1289     uint64_t newBits = Ctx.getTypeSize(T);
1290     if (!bitsInit || newBits < bits) {
1291       bitsInit = true;
1292       bits = newBits;
1293     }
1294 
1295     Ex = CE->getSubExpr();
1296   }
1297 
1298   // We reached a non-cast.  Is it a symbolic value?
1299   QualType T = Ex->getType();
1300 
1301   if (!bitsInit || !T->isIntegralOrEnumerationType() ||
1302       Ctx.getTypeSize(T) > bits)
1303     return UnknownVal();
1304 
1305   return state->getSVal(Ex, LCtx);
1306 }
1307 
1308 static const Stmt *ResolveCondition(const Stmt *Condition,
1309                                     const CFGBlock *B) {
1310   if (const Expr *Ex = dyn_cast<Expr>(Condition))
1311     Condition = Ex->IgnoreParens();
1312 
1313   const BinaryOperator *BO = dyn_cast<BinaryOperator>(Condition);
1314   if (!BO || !BO->isLogicalOp())
1315     return Condition;
1316 
1317   // For logical operations, we still have the case where some branches
1318   // use the traditional "merge" approach and others sink the branch
1319   // directly into the basic blocks representing the logical operation.
1320   // We need to distinguish between those two cases here.
1321 
1322   // The invariants are still shifting, but it is possible that the
1323   // last element in a CFGBlock is not a CFGStmt.  Look for the last
1324   // CFGStmt as the value of the condition.
1325   CFGBlock::const_reverse_iterator I = B->rbegin(), E = B->rend();
1326   for (; I != E; ++I) {
1327     CFGElement Elem = *I;
1328     Optional<CFGStmt> CS = Elem.getAs<CFGStmt>();
1329     if (!CS)
1330       continue;
1331     if (CS->getStmt() != Condition)
1332       break;
1333     return Condition;
1334   }
1335 
1336   assert(I != E);
1337 
1338   while (Condition) {
1339     BO = dyn_cast<BinaryOperator>(Condition);
1340     if (!BO || !BO->isLogicalOp())
1341       return Condition;
1342     Condition = BO->getRHS()->IgnoreParens();
1343   }
1344   llvm_unreachable("could not resolve condition");
1345 }
1346 
1347 void ExprEngine::processBranch(const Stmt *Condition, const Stmt *Term,
1348                                NodeBuilderContext& BldCtx,
1349                                ExplodedNode *Pred,
1350                                ExplodedNodeSet &Dst,
1351                                const CFGBlock *DstT,
1352                                const CFGBlock *DstF) {
1353   const LocationContext *LCtx = Pred->getLocationContext();
1354   PrettyStackTraceLocationContext StackCrashInfo(LCtx);
1355   currBldrCtx = &BldCtx;
1356 
1357   // Check for NULL conditions; e.g. "for(;;)"
1358   if (!Condition) {
1359     BranchNodeBuilder NullCondBldr(Pred, Dst, BldCtx, DstT, DstF);
1360     NullCondBldr.markInfeasible(false);
1361     NullCondBldr.generateNode(Pred->getState(), true, Pred);
1362     return;
1363   }
1364 
1365   SValBuilder &SVB = Pred->getState()->getStateManager().getSValBuilder();
1366   SVal TrueVal = SVB.makeTruthVal(true);
1367   SVal FalseVal = SVB.makeTruthVal(false);
1368 
1369   if (const Expr *Ex = dyn_cast<Expr>(Condition))
1370     Condition = Ex->IgnoreParens();
1371 
1372   // If the value is already available, we don't need to do anything.
1373   if (Pred->getState()->getSVal(Condition, LCtx).isUnknownOrUndef()) {
1374     // Resolve the condition in the presence of nested '||' and '&&'.
1375     Condition = ResolveCondition(Condition, BldCtx.getBlock());
1376   }
1377 
1378   // Cast truth values to the correct type.
1379   if (const Expr *Ex = dyn_cast<Expr>(Condition)) {
1380     TrueVal = SVB.evalCast(TrueVal, Ex->getType(),
1381                            getContext().getLogicalOperationType());
1382     FalseVal = SVB.evalCast(FalseVal, Ex->getType(),
1383                             getContext().getLogicalOperationType());
1384   }
1385 
1386   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
1387                                 Condition->getLocStart(),
1388                                 "Error evaluating branch");
1389 
1390   ExplodedNodeSet CheckersOutSet;
1391   getCheckerManager().runCheckersForBranchCondition(Condition, CheckersOutSet,
1392                                                     Pred, *this);
1393   // We generated only sinks.
1394   if (CheckersOutSet.empty())
1395     return;
1396 
1397   BranchNodeBuilder builder(CheckersOutSet, Dst, BldCtx, DstT, DstF);
1398   for (NodeBuilder::iterator I = CheckersOutSet.begin(),
1399                              E = CheckersOutSet.end(); E != I; ++I) {
1400     ExplodedNode *PredI = *I;
1401 
1402     if (PredI->isSink())
1403       continue;
1404 
1405     ProgramStateRef PrevState = PredI->getState();
1406     SVal X = PrevState->getSVal(Condition, PredI->getLocationContext());
1407 
1408     if (X.isUnknownOrUndef()) {
1409       // Give it a chance to recover from unknown.
1410       if (const Expr *Ex = dyn_cast<Expr>(Condition)) {
1411         if (Ex->getType()->isIntegralOrEnumerationType()) {
1412           // Try to recover some path-sensitivity.  Right now casts of symbolic
1413           // integers that promote their values are currently not tracked well.
1414           // If 'Condition' is such an expression, try and recover the
1415           // underlying value and use that instead.
1416           SVal recovered = RecoverCastedSymbol(getStateManager(),
1417                                                PrevState, Condition,
1418                                                PredI->getLocationContext(),
1419                                                getContext());
1420 
1421           if (!recovered.isUnknown()) {
1422             X = recovered;
1423           }
1424         }
1425       }
1426     }
1427 
1428     ProgramStateRef StTrue, StFalse;
1429 
1430     // If the condition is still unknown, give up.
1431     if (X.isUnknownOrUndef()) {
1432 
1433       StTrue = PrevState->BindExpr(Condition, BldCtx.LC, TrueVal);
1434       StFalse = PrevState->BindExpr(Condition, BldCtx.LC, FalseVal);
1435 
1436       builder.generateNode(StTrue, true, PredI);
1437       builder.generateNode(StFalse, false, PredI);
1438       continue;
1439     }
1440 
1441     DefinedSVal V = X.castAs<DefinedSVal>();
1442     tie(StTrue, StFalse) = PrevState->assume(V);
1443 
1444     // Process the true branch.
1445     if (builder.isFeasible(true)) {
1446       if (StTrue) {
1447         StTrue = StTrue->BindExpr(Condition, BldCtx.LC, TrueVal);
1448         builder.generateNode(StTrue, true, PredI);
1449       } else
1450         builder.markInfeasible(true);
1451     }
1452 
1453     // Process the false branch.
1454     if (builder.isFeasible(false)) {
1455       if (StFalse) {
1456         StFalse = StFalse->BindExpr(Condition, BldCtx.LC, FalseVal);
1457         builder.generateNode(StFalse, false, PredI);
1458       } else
1459         builder.markInfeasible(false);
1460     }
1461   }
1462   currBldrCtx = 0;
1463 }
1464 
1465 /// The GDM component containing the set of global variables which have been
1466 /// previously initialized with explicit initializers.
1467 REGISTER_TRAIT_WITH_PROGRAMSTATE(InitializedGlobalsSet,
1468                                  llvm::ImmutableSet<const VarDecl *>)
1469 
1470 void ExprEngine::processStaticInitializer(const DeclStmt *DS,
1471                                           NodeBuilderContext &BuilderCtx,
1472                                           ExplodedNode *Pred,
1473                                           clang::ento::ExplodedNodeSet &Dst,
1474                                           const CFGBlock *DstT,
1475                                           const CFGBlock *DstF) {
1476   PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
1477   currBldrCtx = &BuilderCtx;
1478 
1479   const VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
1480   ProgramStateRef state = Pred->getState();
1481   bool initHasRun = state->contains<InitializedGlobalsSet>(VD);
1482   BranchNodeBuilder builder(Pred, Dst, BuilderCtx, DstT, DstF);
1483 
1484   if (!initHasRun) {
1485     state = state->add<InitializedGlobalsSet>(VD);
1486   }
1487 
1488   builder.generateNode(state, initHasRun, Pred);
1489   builder.markInfeasible(!initHasRun);
1490 
1491   currBldrCtx = 0;
1492 }
1493 
1494 /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
1495 ///  nodes by processing the 'effects' of a computed goto jump.
1496 void ExprEngine::processIndirectGoto(IndirectGotoNodeBuilder &builder) {
1497 
1498   ProgramStateRef state = builder.getState();
1499   SVal V = state->getSVal(builder.getTarget(), builder.getLocationContext());
1500 
1501   // Three possibilities:
1502   //
1503   //   (1) We know the computed label.
1504   //   (2) The label is NULL (or some other constant), or Undefined.
1505   //   (3) We have no clue about the label.  Dispatch to all targets.
1506   //
1507 
1508   typedef IndirectGotoNodeBuilder::iterator iterator;
1509 
1510   if (Optional<loc::GotoLabel> LV = V.getAs<loc::GotoLabel>()) {
1511     const LabelDecl *L = LV->getLabel();
1512 
1513     for (iterator I = builder.begin(), E = builder.end(); I != E; ++I) {
1514       if (I.getLabel() == L) {
1515         builder.generateNode(I, state);
1516         return;
1517       }
1518     }
1519 
1520     llvm_unreachable("No block with label.");
1521   }
1522 
1523   if (V.getAs<loc::ConcreteInt>() || V.getAs<UndefinedVal>()) {
1524     // Dispatch to the first target and mark it as a sink.
1525     //ExplodedNode* N = builder.generateNode(builder.begin(), state, true);
1526     // FIXME: add checker visit.
1527     //    UndefBranches.insert(N);
1528     return;
1529   }
1530 
1531   // This is really a catch-all.  We don't support symbolics yet.
1532   // FIXME: Implement dispatch for symbolic pointers.
1533 
1534   for (iterator I=builder.begin(), E=builder.end(); I != E; ++I)
1535     builder.generateNode(I, state);
1536 }
1537 
1538 /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
1539 ///  nodes when the control reaches the end of a function.
1540 void ExprEngine::processEndOfFunction(NodeBuilderContext& BC,
1541                                       ExplodedNode *Pred) {
1542   PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
1543   StateMgr.EndPath(Pred->getState());
1544 
1545   ExplodedNodeSet Dst;
1546   if (Pred->getLocationContext()->inTopFrame()) {
1547     // Remove dead symbols.
1548     ExplodedNodeSet AfterRemovedDead;
1549     removeDeadOnEndOfFunction(BC, Pred, AfterRemovedDead);
1550 
1551     // Notify checkers.
1552     for (ExplodedNodeSet::iterator I = AfterRemovedDead.begin(),
1553         E = AfterRemovedDead.end(); I != E; ++I) {
1554       getCheckerManager().runCheckersForEndFunction(BC, Dst, *I, *this);
1555     }
1556   } else {
1557     getCheckerManager().runCheckersForEndFunction(BC, Dst, Pred, *this);
1558   }
1559 
1560   Engine.enqueueEndOfFunction(Dst);
1561 }
1562 
1563 /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
1564 ///  nodes by processing the 'effects' of a switch statement.
1565 void ExprEngine::processSwitch(SwitchNodeBuilder& builder) {
1566   typedef SwitchNodeBuilder::iterator iterator;
1567   ProgramStateRef state = builder.getState();
1568   const Expr *CondE = builder.getCondition();
1569   SVal  CondV_untested = state->getSVal(CondE, builder.getLocationContext());
1570 
1571   if (CondV_untested.isUndef()) {
1572     //ExplodedNode* N = builder.generateDefaultCaseNode(state, true);
1573     // FIXME: add checker
1574     //UndefBranches.insert(N);
1575 
1576     return;
1577   }
1578   DefinedOrUnknownSVal CondV = CondV_untested.castAs<DefinedOrUnknownSVal>();
1579 
1580   ProgramStateRef DefaultSt = state;
1581 
1582   iterator I = builder.begin(), EI = builder.end();
1583   bool defaultIsFeasible = I == EI;
1584 
1585   for ( ; I != EI; ++I) {
1586     // Successor may be pruned out during CFG construction.
1587     if (!I.getBlock())
1588       continue;
1589 
1590     const CaseStmt *Case = I.getCase();
1591 
1592     // Evaluate the LHS of the case value.
1593     llvm::APSInt V1 = Case->getLHS()->EvaluateKnownConstInt(getContext());
1594     assert(V1.getBitWidth() == getContext().getTypeSize(CondE->getType()));
1595 
1596     // Get the RHS of the case, if it exists.
1597     llvm::APSInt V2;
1598     if (const Expr *E = Case->getRHS())
1599       V2 = E->EvaluateKnownConstInt(getContext());
1600     else
1601       V2 = V1;
1602 
1603     // FIXME: Eventually we should replace the logic below with a range
1604     //  comparison, rather than concretize the values within the range.
1605     //  This should be easy once we have "ranges" for NonLVals.
1606 
1607     do {
1608       nonloc::ConcreteInt CaseVal(getBasicVals().getValue(V1));
1609       DefinedOrUnknownSVal Res = svalBuilder.evalEQ(DefaultSt ? DefaultSt : state,
1610                                                CondV, CaseVal);
1611 
1612       // Now "assume" that the case matches.
1613       if (ProgramStateRef stateNew = state->assume(Res, true)) {
1614         builder.generateCaseStmtNode(I, stateNew);
1615 
1616         // If CondV evaluates to a constant, then we know that this
1617         // is the *only* case that we can take, so stop evaluating the
1618         // others.
1619         if (CondV.getAs<nonloc::ConcreteInt>())
1620           return;
1621       }
1622 
1623       // Now "assume" that the case doesn't match.  Add this state
1624       // to the default state (if it is feasible).
1625       if (DefaultSt) {
1626         if (ProgramStateRef stateNew = DefaultSt->assume(Res, false)) {
1627           defaultIsFeasible = true;
1628           DefaultSt = stateNew;
1629         }
1630         else {
1631           defaultIsFeasible = false;
1632           DefaultSt = NULL;
1633         }
1634       }
1635 
1636       // Concretize the next value in the range.
1637       if (V1 == V2)
1638         break;
1639 
1640       ++V1;
1641       assert (V1 <= V2);
1642 
1643     } while (true);
1644   }
1645 
1646   if (!defaultIsFeasible)
1647     return;
1648 
1649   // If we have switch(enum value), the default branch is not
1650   // feasible if all of the enum constants not covered by 'case:' statements
1651   // are not feasible values for the switch condition.
1652   //
1653   // Note that this isn't as accurate as it could be.  Even if there isn't
1654   // a case for a particular enum value as long as that enum value isn't
1655   // feasible then it shouldn't be considered for making 'default:' reachable.
1656   const SwitchStmt *SS = builder.getSwitch();
1657   const Expr *CondExpr = SS->getCond()->IgnoreParenImpCasts();
1658   if (CondExpr->getType()->getAs<EnumType>()) {
1659     if (SS->isAllEnumCasesCovered())
1660       return;
1661   }
1662 
1663   builder.generateDefaultCaseNode(DefaultSt);
1664 }
1665 
1666 //===----------------------------------------------------------------------===//
1667 // Transfer functions: Loads and stores.
1668 //===----------------------------------------------------------------------===//
1669 
1670 void ExprEngine::VisitCommonDeclRefExpr(const Expr *Ex, const NamedDecl *D,
1671                                         ExplodedNode *Pred,
1672                                         ExplodedNodeSet &Dst) {
1673   StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
1674 
1675   ProgramStateRef state = Pred->getState();
1676   const LocationContext *LCtx = Pred->getLocationContext();
1677 
1678   if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1679     // C permits "extern void v", and if you cast the address to a valid type,
1680     // you can even do things with it. We simply pretend
1681     assert(Ex->isGLValue() || VD->getType()->isVoidType());
1682     SVal V = state->getLValue(VD, Pred->getLocationContext());
1683 
1684     // For references, the 'lvalue' is the pointer address stored in the
1685     // reference region.
1686     if (VD->getType()->isReferenceType()) {
1687       if (const MemRegion *R = V.getAsRegion())
1688         V = state->getSVal(R);
1689       else
1690         V = UnknownVal();
1691     }
1692 
1693     Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V), 0,
1694                       ProgramPoint::PostLValueKind);
1695     return;
1696   }
1697   if (const EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {
1698     assert(!Ex->isGLValue());
1699     SVal V = svalBuilder.makeIntVal(ED->getInitVal());
1700     Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V));
1701     return;
1702   }
1703   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
1704     SVal V = svalBuilder.getFunctionPointer(FD);
1705     Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V), 0,
1706                       ProgramPoint::PostLValueKind);
1707     return;
1708   }
1709   if (isa<FieldDecl>(D)) {
1710     // FIXME: Compute lvalue of field pointers-to-member.
1711     // Right now we just use a non-null void pointer, so that it gives proper
1712     // results in boolean contexts.
1713     SVal V = svalBuilder.conjureSymbolVal(Ex, LCtx, getContext().VoidPtrTy,
1714                                           currBldrCtx->blockCount());
1715     state = state->assume(V.castAs<DefinedOrUnknownSVal>(), true);
1716     Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V), 0,
1717 		      ProgramPoint::PostLValueKind);
1718     return;
1719   }
1720 
1721   llvm_unreachable("Support for this Decl not implemented.");
1722 }
1723 
1724 /// VisitArraySubscriptExpr - Transfer function for array accesses
1725 void ExprEngine::VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *A,
1726                                              ExplodedNode *Pred,
1727                                              ExplodedNodeSet &Dst){
1728 
1729   const Expr *Base = A->getBase()->IgnoreParens();
1730   const Expr *Idx  = A->getIdx()->IgnoreParens();
1731 
1732 
1733   ExplodedNodeSet checkerPreStmt;
1734   getCheckerManager().runCheckersForPreStmt(checkerPreStmt, Pred, A, *this);
1735 
1736   StmtNodeBuilder Bldr(checkerPreStmt, Dst, *currBldrCtx);
1737 
1738   for (ExplodedNodeSet::iterator it = checkerPreStmt.begin(),
1739                                  ei = checkerPreStmt.end(); it != ei; ++it) {
1740     const LocationContext *LCtx = (*it)->getLocationContext();
1741     ProgramStateRef state = (*it)->getState();
1742     SVal V = state->getLValue(A->getType(),
1743                               state->getSVal(Idx, LCtx),
1744                               state->getSVal(Base, LCtx));
1745     assert(A->isGLValue());
1746     Bldr.generateNode(A, *it, state->BindExpr(A, LCtx, V), 0,
1747                       ProgramPoint::PostLValueKind);
1748   }
1749 }
1750 
1751 /// VisitMemberExpr - Transfer function for member expressions.
1752 void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
1753                                  ExplodedNodeSet &TopDst) {
1754 
1755   StmtNodeBuilder Bldr(Pred, TopDst, *currBldrCtx);
1756   ExplodedNodeSet Dst;
1757   ValueDecl *Member = M->getMemberDecl();
1758 
1759   // Handle static member variables and enum constants accessed via
1760   // member syntax.
1761   if (isa<VarDecl>(Member) || isa<EnumConstantDecl>(Member)) {
1762     Bldr.takeNodes(Pred);
1763     VisitCommonDeclRefExpr(M, Member, Pred, Dst);
1764     Bldr.addNodes(Dst);
1765     return;
1766   }
1767 
1768   ProgramStateRef state = Pred->getState();
1769   const LocationContext *LCtx = Pred->getLocationContext();
1770   Expr *BaseExpr = M->getBase();
1771 
1772   // Handle C++ method calls.
1773   if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Member)) {
1774     if (MD->isInstance())
1775       state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr);
1776 
1777     SVal MDVal = svalBuilder.getFunctionPointer(MD);
1778     state = state->BindExpr(M, LCtx, MDVal);
1779 
1780     Bldr.generateNode(M, Pred, state);
1781     return;
1782   }
1783 
1784   // Handle regular struct fields / member variables.
1785   state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr);
1786   SVal baseExprVal = state->getSVal(BaseExpr, LCtx);
1787 
1788   FieldDecl *field = cast<FieldDecl>(Member);
1789   SVal L = state->getLValue(field, baseExprVal);
1790 
1791   if (M->isGLValue() || M->getType()->isArrayType()) {
1792 
1793     // We special case rvalue of array type because the analyzer cannot reason
1794     // about it, since we expect all regions to be wrapped in Locs. So we will
1795     // treat these as lvalues assuming that they will decay to pointers as soon
1796     // as they are used.
1797     if (!M->isGLValue()) {
1798       assert(M->getType()->isArrayType());
1799       const ImplicitCastExpr *PE =
1800         dyn_cast<ImplicitCastExpr>(Pred->getParentMap().getParent(M));
1801       if (!PE || PE->getCastKind() != CK_ArrayToPointerDecay) {
1802         assert(false &&
1803                "We assume that array is always wrapped in ArrayToPointerDecay");
1804         L = UnknownVal();
1805       }
1806     }
1807 
1808     if (field->getType()->isReferenceType()) {
1809       if (const MemRegion *R = L.getAsRegion())
1810         L = state->getSVal(R);
1811       else
1812         L = UnknownVal();
1813     }
1814 
1815     Bldr.generateNode(M, Pred, state->BindExpr(M, LCtx, L), 0,
1816                       ProgramPoint::PostLValueKind);
1817   } else {
1818     Bldr.takeNodes(Pred);
1819     evalLoad(Dst, M, M, Pred, state, L);
1820     Bldr.addNodes(Dst);
1821   }
1822 }
1823 
1824 namespace {
1825 class CollectReachableSymbolsCallback : public SymbolVisitor {
1826   InvalidatedSymbols Symbols;
1827 public:
1828   CollectReachableSymbolsCallback(ProgramStateRef State) {}
1829   const InvalidatedSymbols &getSymbols() const { return Symbols; }
1830 
1831   bool VisitSymbol(SymbolRef Sym) {
1832     Symbols.insert(Sym);
1833     return true;
1834   }
1835 };
1836 } // end anonymous namespace
1837 
1838 // A value escapes in three possible cases:
1839 // (1) We are binding to something that is not a memory region.
1840 // (2) We are binding to a MemrRegion that does not have stack storage.
1841 // (3) We are binding to a MemRegion with stack storage that the store
1842 //     does not understand.
1843 ProgramStateRef ExprEngine::processPointerEscapedOnBind(ProgramStateRef State,
1844                                                         SVal Loc, SVal Val) {
1845   // Are we storing to something that causes the value to "escape"?
1846   bool escapes = true;
1847 
1848   // TODO: Move to StoreManager.
1849   if (Optional<loc::MemRegionVal> regionLoc = Loc.getAs<loc::MemRegionVal>()) {
1850     escapes = !regionLoc->getRegion()->hasStackStorage();
1851 
1852     if (!escapes) {
1853       // To test (3), generate a new state with the binding added.  If it is
1854       // the same state, then it escapes (since the store cannot represent
1855       // the binding).
1856       // Do this only if we know that the store is not supposed to generate the
1857       // same state.
1858       SVal StoredVal = State->getSVal(regionLoc->getRegion());
1859       if (StoredVal != Val)
1860         escapes = (State == (State->bindLoc(*regionLoc, Val)));
1861     }
1862   }
1863 
1864   // If our store can represent the binding and we aren't storing to something
1865   // that doesn't have local storage then just return and have the simulation
1866   // state continue as is.
1867   if (!escapes)
1868     return State;
1869 
1870   // Otherwise, find all symbols referenced by 'val' that we are tracking
1871   // and stop tracking them.
1872   CollectReachableSymbolsCallback Scanner =
1873       State->scanReachableSymbols<CollectReachableSymbolsCallback>(Val);
1874   const InvalidatedSymbols &EscapedSymbols = Scanner.getSymbols();
1875   State = getCheckerManager().runCheckersForPointerEscape(State,
1876                                                           EscapedSymbols,
1877                                                           /*CallEvent*/ 0,
1878                                                           PSK_EscapeOnBind);
1879 
1880   return State;
1881 }
1882 
1883 ProgramStateRef
1884 ExprEngine::notifyCheckersOfPointerEscape(ProgramStateRef State,
1885     const InvalidatedSymbols *Invalidated,
1886     ArrayRef<const MemRegion *> ExplicitRegions,
1887     ArrayRef<const MemRegion *> Regions,
1888     const CallEvent *Call,
1889     bool IsConst) {
1890 
1891   if (!Invalidated || Invalidated->empty())
1892     return State;
1893 
1894   if (!Call)
1895     return getCheckerManager().runCheckersForPointerEscape(State,
1896                                                            *Invalidated,
1897                                                            0,
1898                                                            PSK_EscapeOther,
1899                                                            IsConst);
1900 
1901   // Note: Due to current limitations of RegionStore, we only process the top
1902   // level const pointers correctly. The lower level const pointers are
1903   // currently treated as non-const.
1904   if (IsConst)
1905     return getCheckerManager().runCheckersForPointerEscape(State,
1906                                                         *Invalidated,
1907                                                         Call,
1908                                                         PSK_DirectEscapeOnCall,
1909                                                         true);
1910 
1911   // If the symbols were invalidated by a call, we want to find out which ones
1912   // were invalidated directly due to being arguments to the call.
1913   InvalidatedSymbols SymbolsDirectlyInvalidated;
1914   for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(),
1915       E = ExplicitRegions.end(); I != E; ++I) {
1916     if (const SymbolicRegion *R = (*I)->StripCasts()->getAs<SymbolicRegion>())
1917       SymbolsDirectlyInvalidated.insert(R->getSymbol());
1918   }
1919 
1920   InvalidatedSymbols SymbolsIndirectlyInvalidated;
1921   for (InvalidatedSymbols::const_iterator I=Invalidated->begin(),
1922       E = Invalidated->end(); I!=E; ++I) {
1923     SymbolRef sym = *I;
1924     if (SymbolsDirectlyInvalidated.count(sym))
1925       continue;
1926     SymbolsIndirectlyInvalidated.insert(sym);
1927   }
1928 
1929   if (!SymbolsDirectlyInvalidated.empty())
1930     State = getCheckerManager().runCheckersForPointerEscape(State,
1931         SymbolsDirectlyInvalidated, Call, PSK_DirectEscapeOnCall);
1932 
1933   // Notify about the symbols that get indirectly invalidated by the call.
1934   if (!SymbolsIndirectlyInvalidated.empty())
1935     State = getCheckerManager().runCheckersForPointerEscape(State,
1936         SymbolsIndirectlyInvalidated, Call, PSK_IndirectEscapeOnCall);
1937 
1938   return State;
1939 }
1940 
1941 /// evalBind - Handle the semantics of binding a value to a specific location.
1942 ///  This method is used by evalStore and (soon) VisitDeclStmt, and others.
1943 void ExprEngine::evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE,
1944                           ExplodedNode *Pred,
1945                           SVal location, SVal Val,
1946                           bool atDeclInit, const ProgramPoint *PP) {
1947 
1948   const LocationContext *LC = Pred->getLocationContext();
1949   PostStmt PS(StoreE, LC);
1950   if (!PP)
1951     PP = &PS;
1952 
1953   // Do a previsit of the bind.
1954   ExplodedNodeSet CheckedSet;
1955   getCheckerManager().runCheckersForBind(CheckedSet, Pred, location, Val,
1956                                          StoreE, *this, *PP);
1957 
1958 
1959   StmtNodeBuilder Bldr(CheckedSet, Dst, *currBldrCtx);
1960 
1961   // If the location is not a 'Loc', it will already be handled by
1962   // the checkers.  There is nothing left to do.
1963   if (!location.getAs<Loc>()) {
1964     const ProgramPoint L = PostStore(StoreE, LC, /*Loc*/0, /*tag*/0);
1965     ProgramStateRef state = Pred->getState();
1966     state = processPointerEscapedOnBind(state, location, Val);
1967     Bldr.generateNode(L, state, Pred);
1968     return;
1969   }
1970 
1971 
1972   for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
1973        I!=E; ++I) {
1974     ExplodedNode *PredI = *I;
1975     ProgramStateRef state = PredI->getState();
1976 
1977     state = processPointerEscapedOnBind(state, location, Val);
1978 
1979     // When binding the value, pass on the hint that this is a initialization.
1980     // For initializations, we do not need to inform clients of region
1981     // changes.
1982     state = state->bindLoc(location.castAs<Loc>(),
1983                            Val, /* notifyChanges = */ !atDeclInit);
1984 
1985     const MemRegion *LocReg = 0;
1986     if (Optional<loc::MemRegionVal> LocRegVal =
1987             location.getAs<loc::MemRegionVal>()) {
1988       LocReg = LocRegVal->getRegion();
1989     }
1990 
1991     const ProgramPoint L = PostStore(StoreE, LC, LocReg, 0);
1992     Bldr.generateNode(L, state, PredI);
1993   }
1994 }
1995 
1996 /// evalStore - Handle the semantics of a store via an assignment.
1997 ///  @param Dst The node set to store generated state nodes
1998 ///  @param AssignE The assignment expression if the store happens in an
1999 ///         assignment.
2000 ///  @param LocationE The location expression that is stored to.
2001 ///  @param state The current simulation state
2002 ///  @param location The location to store the value
2003 ///  @param Val The value to be stored
2004 void ExprEngine::evalStore(ExplodedNodeSet &Dst, const Expr *AssignE,
2005                              const Expr *LocationE,
2006                              ExplodedNode *Pred,
2007                              ProgramStateRef state, SVal location, SVal Val,
2008                              const ProgramPointTag *tag) {
2009   // Proceed with the store.  We use AssignE as the anchor for the PostStore
2010   // ProgramPoint if it is non-NULL, and LocationE otherwise.
2011   const Expr *StoreE = AssignE ? AssignE : LocationE;
2012 
2013   // Evaluate the location (checks for bad dereferences).
2014   ExplodedNodeSet Tmp;
2015   evalLocation(Tmp, AssignE, LocationE, Pred, state, location, tag, false);
2016 
2017   if (Tmp.empty())
2018     return;
2019 
2020   if (location.isUndef())
2021     return;
2022 
2023   for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI)
2024     evalBind(Dst, StoreE, *NI, location, Val, false);
2025 }
2026 
2027 void ExprEngine::evalLoad(ExplodedNodeSet &Dst,
2028                           const Expr *NodeEx,
2029                           const Expr *BoundEx,
2030                           ExplodedNode *Pred,
2031                           ProgramStateRef state,
2032                           SVal location,
2033                           const ProgramPointTag *tag,
2034                           QualType LoadTy)
2035 {
2036   assert(!location.getAs<NonLoc>() && "location cannot be a NonLoc.");
2037 
2038   // Are we loading from a region?  This actually results in two loads; one
2039   // to fetch the address of the referenced value and one to fetch the
2040   // referenced value.
2041   if (const TypedValueRegion *TR =
2042         dyn_cast_or_null<TypedValueRegion>(location.getAsRegion())) {
2043 
2044     QualType ValTy = TR->getValueType();
2045     if (const ReferenceType *RT = ValTy->getAs<ReferenceType>()) {
2046       static SimpleProgramPointTag
2047              loadReferenceTag("ExprEngine : Load Reference");
2048       ExplodedNodeSet Tmp;
2049       evalLoadCommon(Tmp, NodeEx, BoundEx, Pred, state,
2050                      location, &loadReferenceTag,
2051                      getContext().getPointerType(RT->getPointeeType()));
2052 
2053       // Perform the load from the referenced value.
2054       for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end() ; I!=E; ++I) {
2055         state = (*I)->getState();
2056         location = state->getSVal(BoundEx, (*I)->getLocationContext());
2057         evalLoadCommon(Dst, NodeEx, BoundEx, *I, state, location, tag, LoadTy);
2058       }
2059       return;
2060     }
2061   }
2062 
2063   evalLoadCommon(Dst, NodeEx, BoundEx, Pred, state, location, tag, LoadTy);
2064 }
2065 
2066 void ExprEngine::evalLoadCommon(ExplodedNodeSet &Dst,
2067                                 const Expr *NodeEx,
2068                                 const Expr *BoundEx,
2069                                 ExplodedNode *Pred,
2070                                 ProgramStateRef state,
2071                                 SVal location,
2072                                 const ProgramPointTag *tag,
2073                                 QualType LoadTy) {
2074   assert(NodeEx);
2075   assert(BoundEx);
2076   // Evaluate the location (checks for bad dereferences).
2077   ExplodedNodeSet Tmp;
2078   evalLocation(Tmp, NodeEx, BoundEx, Pred, state, location, tag, true);
2079   if (Tmp.empty())
2080     return;
2081 
2082   StmtNodeBuilder Bldr(Tmp, Dst, *currBldrCtx);
2083   if (location.isUndef())
2084     return;
2085 
2086   // Proceed with the load.
2087   for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI) {
2088     state = (*NI)->getState();
2089     const LocationContext *LCtx = (*NI)->getLocationContext();
2090 
2091     SVal V = UnknownVal();
2092     if (location.isValid()) {
2093       if (LoadTy.isNull())
2094         LoadTy = BoundEx->getType();
2095       V = state->getSVal(location.castAs<Loc>(), LoadTy);
2096     }
2097 
2098     Bldr.generateNode(NodeEx, *NI, state->BindExpr(BoundEx, LCtx, V), tag,
2099                       ProgramPoint::PostLoadKind);
2100   }
2101 }
2102 
2103 void ExprEngine::evalLocation(ExplodedNodeSet &Dst,
2104                               const Stmt *NodeEx,
2105                               const Stmt *BoundEx,
2106                               ExplodedNode *Pred,
2107                               ProgramStateRef state,
2108                               SVal location,
2109                               const ProgramPointTag *tag,
2110                               bool isLoad) {
2111   StmtNodeBuilder BldrTop(Pred, Dst, *currBldrCtx);
2112   // Early checks for performance reason.
2113   if (location.isUnknown()) {
2114     return;
2115   }
2116 
2117   ExplodedNodeSet Src;
2118   BldrTop.takeNodes(Pred);
2119   StmtNodeBuilder Bldr(Pred, Src, *currBldrCtx);
2120   if (Pred->getState() != state) {
2121     // Associate this new state with an ExplodedNode.
2122     // FIXME: If I pass null tag, the graph is incorrect, e.g for
2123     //   int *p;
2124     //   p = 0;
2125     //   *p = 0xDEADBEEF;
2126     // "p = 0" is not noted as "Null pointer value stored to 'p'" but
2127     // instead "int *p" is noted as
2128     // "Variable 'p' initialized to a null pointer value"
2129 
2130     static SimpleProgramPointTag tag("ExprEngine: Location");
2131     Bldr.generateNode(NodeEx, Pred, state, &tag);
2132   }
2133   ExplodedNodeSet Tmp;
2134   getCheckerManager().runCheckersForLocation(Tmp, Src, location, isLoad,
2135                                              NodeEx, BoundEx, *this);
2136   BldrTop.addNodes(Tmp);
2137 }
2138 
2139 std::pair<const ProgramPointTag *, const ProgramPointTag*>
2140 ExprEngine::geteagerlyAssumeBinOpBifurcationTags() {
2141   static SimpleProgramPointTag
2142          eagerlyAssumeBinOpBifurcationTrue("ExprEngine : Eagerly Assume True"),
2143          eagerlyAssumeBinOpBifurcationFalse("ExprEngine : Eagerly Assume False");
2144   return std::make_pair(&eagerlyAssumeBinOpBifurcationTrue,
2145                         &eagerlyAssumeBinOpBifurcationFalse);
2146 }
2147 
2148 void ExprEngine::evalEagerlyAssumeBinOpBifurcation(ExplodedNodeSet &Dst,
2149                                                    ExplodedNodeSet &Src,
2150                                                    const Expr *Ex) {
2151   StmtNodeBuilder Bldr(Src, Dst, *currBldrCtx);
2152 
2153   for (ExplodedNodeSet::iterator I=Src.begin(), E=Src.end(); I!=E; ++I) {
2154     ExplodedNode *Pred = *I;
2155     // Test if the previous node was as the same expression.  This can happen
2156     // when the expression fails to evaluate to anything meaningful and
2157     // (as an optimization) we don't generate a node.
2158     ProgramPoint P = Pred->getLocation();
2159     if (!P.getAs<PostStmt>() || P.castAs<PostStmt>().getStmt() != Ex) {
2160       continue;
2161     }
2162 
2163     ProgramStateRef state = Pred->getState();
2164     SVal V = state->getSVal(Ex, Pred->getLocationContext());
2165     Optional<nonloc::SymbolVal> SEV = V.getAs<nonloc::SymbolVal>();
2166     if (SEV && SEV->isExpression()) {
2167       const std::pair<const ProgramPointTag *, const ProgramPointTag*> &tags =
2168         geteagerlyAssumeBinOpBifurcationTags();
2169 
2170       ProgramStateRef StateTrue, StateFalse;
2171       tie(StateTrue, StateFalse) = state->assume(*SEV);
2172 
2173       // First assume that the condition is true.
2174       if (StateTrue) {
2175         SVal Val = svalBuilder.makeIntVal(1U, Ex->getType());
2176         StateTrue = StateTrue->BindExpr(Ex, Pred->getLocationContext(), Val);
2177         Bldr.generateNode(Ex, Pred, StateTrue, tags.first);
2178       }
2179 
2180       // Next, assume that the condition is false.
2181       if (StateFalse) {
2182         SVal Val = svalBuilder.makeIntVal(0U, Ex->getType());
2183         StateFalse = StateFalse->BindExpr(Ex, Pred->getLocationContext(), Val);
2184         Bldr.generateNode(Ex, Pred, StateFalse, tags.second);
2185       }
2186     }
2187   }
2188 }
2189 
2190 void ExprEngine::VisitGCCAsmStmt(const GCCAsmStmt *A, ExplodedNode *Pred,
2191                                  ExplodedNodeSet &Dst) {
2192   StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
2193   // We have processed both the inputs and the outputs.  All of the outputs
2194   // should evaluate to Locs.  Nuke all of their values.
2195 
2196   // FIXME: Some day in the future it would be nice to allow a "plug-in"
2197   // which interprets the inline asm and stores proper results in the
2198   // outputs.
2199 
2200   ProgramStateRef state = Pred->getState();
2201 
2202   for (GCCAsmStmt::const_outputs_iterator OI = A->begin_outputs(),
2203        OE = A->end_outputs(); OI != OE; ++OI) {
2204     SVal X = state->getSVal(*OI, Pred->getLocationContext());
2205     assert (!X.getAs<NonLoc>());  // Should be an Lval, or unknown, undef.
2206 
2207     if (Optional<Loc> LV = X.getAs<Loc>())
2208       state = state->bindLoc(*LV, UnknownVal());
2209   }
2210 
2211   Bldr.generateNode(A, Pred, state);
2212 }
2213 
2214 void ExprEngine::VisitMSAsmStmt(const MSAsmStmt *A, ExplodedNode *Pred,
2215                                 ExplodedNodeSet &Dst) {
2216   StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
2217   Bldr.generateNode(A, Pred, Pred->getState());
2218 }
2219 
2220 //===----------------------------------------------------------------------===//
2221 // Visualization.
2222 //===----------------------------------------------------------------------===//
2223 
2224 #ifndef NDEBUG
2225 static ExprEngine* GraphPrintCheckerState;
2226 static SourceManager* GraphPrintSourceManager;
2227 
2228 namespace llvm {
2229 template<>
2230 struct DOTGraphTraits<ExplodedNode*> :
2231   public DefaultDOTGraphTraits {
2232 
2233   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
2234 
2235   // FIXME: Since we do not cache error nodes in ExprEngine now, this does not
2236   // work.
2237   static std::string getNodeAttributes(const ExplodedNode *N, void*) {
2238 
2239 #if 0
2240       // FIXME: Replace with a general scheme to tell if the node is
2241       // an error node.
2242     if (GraphPrintCheckerState->isImplicitNullDeref(N) ||
2243         GraphPrintCheckerState->isExplicitNullDeref(N) ||
2244         GraphPrintCheckerState->isUndefDeref(N) ||
2245         GraphPrintCheckerState->isUndefStore(N) ||
2246         GraphPrintCheckerState->isUndefControlFlow(N) ||
2247         GraphPrintCheckerState->isUndefResult(N) ||
2248         GraphPrintCheckerState->isBadCall(N) ||
2249         GraphPrintCheckerState->isUndefArg(N))
2250       return "color=\"red\",style=\"filled\"";
2251 
2252     if (GraphPrintCheckerState->isNoReturnCall(N))
2253       return "color=\"blue\",style=\"filled\"";
2254 #endif
2255     return "";
2256   }
2257 
2258   static void printLocation(raw_ostream &Out, SourceLocation SLoc) {
2259     if (SLoc.isFileID()) {
2260       Out << "\\lline="
2261         << GraphPrintSourceManager->getExpansionLineNumber(SLoc)
2262         << " col="
2263         << GraphPrintSourceManager->getExpansionColumnNumber(SLoc)
2264         << "\\l";
2265     }
2266   }
2267 
2268   static std::string getNodeLabel(const ExplodedNode *N, void*){
2269 
2270     std::string sbuf;
2271     llvm::raw_string_ostream Out(sbuf);
2272 
2273     // Program Location.
2274     ProgramPoint Loc = N->getLocation();
2275 
2276     switch (Loc.getKind()) {
2277       case ProgramPoint::BlockEntranceKind: {
2278         Out << "Block Entrance: B"
2279             << Loc.castAs<BlockEntrance>().getBlock()->getBlockID();
2280         if (const NamedDecl *ND =
2281                     dyn_cast<NamedDecl>(Loc.getLocationContext()->getDecl())) {
2282           Out << " (";
2283           ND->printName(Out);
2284           Out << ")";
2285         }
2286         break;
2287       }
2288 
2289       case ProgramPoint::BlockExitKind:
2290         assert (false);
2291         break;
2292 
2293       case ProgramPoint::CallEnterKind:
2294         Out << "CallEnter";
2295         break;
2296 
2297       case ProgramPoint::CallExitBeginKind:
2298         Out << "CallExitBegin";
2299         break;
2300 
2301       case ProgramPoint::CallExitEndKind:
2302         Out << "CallExitEnd";
2303         break;
2304 
2305       case ProgramPoint::PostStmtPurgeDeadSymbolsKind:
2306         Out << "PostStmtPurgeDeadSymbols";
2307         break;
2308 
2309       case ProgramPoint::PreStmtPurgeDeadSymbolsKind:
2310         Out << "PreStmtPurgeDeadSymbols";
2311         break;
2312 
2313       case ProgramPoint::EpsilonKind:
2314         Out << "Epsilon Point";
2315         break;
2316 
2317       case ProgramPoint::PreImplicitCallKind: {
2318         ImplicitCallPoint PC = Loc.castAs<ImplicitCallPoint>();
2319         Out << "PreCall: ";
2320 
2321         // FIXME: Get proper printing options.
2322         PC.getDecl()->print(Out, LangOptions());
2323         printLocation(Out, PC.getLocation());
2324         break;
2325       }
2326 
2327       case ProgramPoint::PostImplicitCallKind: {
2328         ImplicitCallPoint PC = Loc.castAs<ImplicitCallPoint>();
2329         Out << "PostCall: ";
2330 
2331         // FIXME: Get proper printing options.
2332         PC.getDecl()->print(Out, LangOptions());
2333         printLocation(Out, PC.getLocation());
2334         break;
2335       }
2336 
2337       case ProgramPoint::PostInitializerKind: {
2338         Out << "PostInitializer: ";
2339         const CXXCtorInitializer *Init =
2340           Loc.castAs<PostInitializer>().getInitializer();
2341         if (const FieldDecl *FD = Init->getAnyMember())
2342           Out << *FD;
2343         else {
2344           QualType Ty = Init->getTypeSourceInfo()->getType();
2345           Ty = Ty.getLocalUnqualifiedType();
2346           LangOptions LO; // FIXME.
2347           Ty.print(Out, LO);
2348         }
2349         break;
2350       }
2351 
2352       case ProgramPoint::BlockEdgeKind: {
2353         const BlockEdge &E = Loc.castAs<BlockEdge>();
2354         Out << "Edge: (B" << E.getSrc()->getBlockID() << ", B"
2355             << E.getDst()->getBlockID()  << ')';
2356 
2357         if (const Stmt *T = E.getSrc()->getTerminator()) {
2358           SourceLocation SLoc = T->getLocStart();
2359 
2360           Out << "\\|Terminator: ";
2361           LangOptions LO; // FIXME.
2362           E.getSrc()->printTerminator(Out, LO);
2363 
2364           if (SLoc.isFileID()) {
2365             Out << "\\lline="
2366               << GraphPrintSourceManager->getExpansionLineNumber(SLoc)
2367               << " col="
2368               << GraphPrintSourceManager->getExpansionColumnNumber(SLoc);
2369           }
2370 
2371           if (isa<SwitchStmt>(T)) {
2372             const Stmt *Label = E.getDst()->getLabel();
2373 
2374             if (Label) {
2375               if (const CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
2376                 Out << "\\lcase ";
2377                 LangOptions LO; // FIXME.
2378                 C->getLHS()->printPretty(Out, 0, PrintingPolicy(LO));
2379 
2380                 if (const Stmt *RHS = C->getRHS()) {
2381                   Out << " .. ";
2382                   RHS->printPretty(Out, 0, PrintingPolicy(LO));
2383                 }
2384 
2385                 Out << ":";
2386               }
2387               else {
2388                 assert (isa<DefaultStmt>(Label));
2389                 Out << "\\ldefault:";
2390               }
2391             }
2392             else
2393               Out << "\\l(implicit) default:";
2394           }
2395           else if (isa<IndirectGotoStmt>(T)) {
2396             // FIXME
2397           }
2398           else {
2399             Out << "\\lCondition: ";
2400             if (*E.getSrc()->succ_begin() == E.getDst())
2401               Out << "true";
2402             else
2403               Out << "false";
2404           }
2405 
2406           Out << "\\l";
2407         }
2408 
2409 #if 0
2410           // FIXME: Replace with a general scheme to determine
2411           // the name of the check.
2412         if (GraphPrintCheckerState->isUndefControlFlow(N)) {
2413           Out << "\\|Control-flow based on\\lUndefined value.\\l";
2414         }
2415 #endif
2416         break;
2417       }
2418 
2419       default: {
2420         const Stmt *S = Loc.castAs<StmtPoint>().getStmt();
2421 
2422         Out << S->getStmtClassName() << ' ' << (const void*) S << ' ';
2423         LangOptions LO; // FIXME.
2424         S->printPretty(Out, 0, PrintingPolicy(LO));
2425         printLocation(Out, S->getLocStart());
2426 
2427         if (Loc.getAs<PreStmt>())
2428           Out << "\\lPreStmt\\l;";
2429         else if (Loc.getAs<PostLoad>())
2430           Out << "\\lPostLoad\\l;";
2431         else if (Loc.getAs<PostStore>())
2432           Out << "\\lPostStore\\l";
2433         else if (Loc.getAs<PostLValue>())
2434           Out << "\\lPostLValue\\l";
2435 
2436 #if 0
2437           // FIXME: Replace with a general scheme to determine
2438           // the name of the check.
2439         if (GraphPrintCheckerState->isImplicitNullDeref(N))
2440           Out << "\\|Implicit-Null Dereference.\\l";
2441         else if (GraphPrintCheckerState->isExplicitNullDeref(N))
2442           Out << "\\|Explicit-Null Dereference.\\l";
2443         else if (GraphPrintCheckerState->isUndefDeref(N))
2444           Out << "\\|Dereference of undefialied value.\\l";
2445         else if (GraphPrintCheckerState->isUndefStore(N))
2446           Out << "\\|Store to Undefined Loc.";
2447         else if (GraphPrintCheckerState->isUndefResult(N))
2448           Out << "\\|Result of operation is undefined.";
2449         else if (GraphPrintCheckerState->isNoReturnCall(N))
2450           Out << "\\|Call to function marked \"noreturn\".";
2451         else if (GraphPrintCheckerState->isBadCall(N))
2452           Out << "\\|Call to NULL/Undefined.";
2453         else if (GraphPrintCheckerState->isUndefArg(N))
2454           Out << "\\|Argument in call is undefined";
2455 #endif
2456 
2457         break;
2458       }
2459     }
2460 
2461     ProgramStateRef state = N->getState();
2462     Out << "\\|StateID: " << (const void*) state.getPtr()
2463         << " NodeID: " << (const void*) N << "\\|";
2464     state->printDOT(Out);
2465 
2466     Out << "\\l";
2467 
2468     if (const ProgramPointTag *tag = Loc.getTag()) {
2469       Out << "\\|Tag: " << tag->getTagDescription();
2470       Out << "\\l";
2471     }
2472     return Out.str();
2473   }
2474 };
2475 } // end llvm namespace
2476 #endif
2477 
2478 #ifndef NDEBUG
2479 template <typename ITERATOR>
2480 ExplodedNode *GetGraphNode(ITERATOR I) { return *I; }
2481 
2482 template <> ExplodedNode*
2483 GetGraphNode<llvm::DenseMap<ExplodedNode*, Expr*>::iterator>
2484   (llvm::DenseMap<ExplodedNode*, Expr*>::iterator I) {
2485   return I->first;
2486 }
2487 #endif
2488 
2489 void ExprEngine::ViewGraph(bool trim) {
2490 #ifndef NDEBUG
2491   if (trim) {
2492     std::vector<const ExplodedNode*> Src;
2493 
2494     // Flush any outstanding reports to make sure we cover all the nodes.
2495     // This does not cause them to get displayed.
2496     for (BugReporter::iterator I=BR.begin(), E=BR.end(); I!=E; ++I)
2497       const_cast<BugType*>(*I)->FlushReports(BR);
2498 
2499     // Iterate through the reports and get their nodes.
2500     for (BugReporter::EQClasses_iterator
2501            EI = BR.EQClasses_begin(), EE = BR.EQClasses_end(); EI != EE; ++EI) {
2502       ExplodedNode *N = const_cast<ExplodedNode*>(EI->begin()->getErrorNode());
2503       if (N) Src.push_back(N);
2504     }
2505 
2506     ViewGraph(Src);
2507   }
2508   else {
2509     GraphPrintCheckerState = this;
2510     GraphPrintSourceManager = &getContext().getSourceManager();
2511 
2512     llvm::ViewGraph(*G.roots_begin(), "ExprEngine");
2513 
2514     GraphPrintCheckerState = NULL;
2515     GraphPrintSourceManager = NULL;
2516   }
2517 #endif
2518 }
2519 
2520 void ExprEngine::ViewGraph(ArrayRef<const ExplodedNode*> Nodes) {
2521 #ifndef NDEBUG
2522   GraphPrintCheckerState = this;
2523   GraphPrintSourceManager = &getContext().getSourceManager();
2524 
2525   OwningPtr<ExplodedGraph> TrimmedG(G.trim(Nodes));
2526 
2527   if (!TrimmedG.get())
2528     llvm::errs() << "warning: Trimmed ExplodedGraph is empty.\n";
2529   else
2530     llvm::ViewGraph(*TrimmedG->roots_begin(), "TrimmedExprEngine");
2531 
2532   GraphPrintCheckerState = NULL;
2533   GraphPrintSourceManager = NULL;
2534 #endif
2535 }
2536