1 //= ProgramState.cpp - Path-Sensitive "State" for tracking values --*- C++ -*--=
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file implements ProgramState and ProgramStateManager.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
14 #include "clang/Analysis/CFG.h"
15 #include "clang/Basic/JsonSupport.h"
16 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicType.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
21 #include "llvm/Support/raw_ostream.h"
22 
23 using namespace clang;
24 using namespace ento;
25 
26 namespace clang { namespace  ento {
27 /// Increments the number of times this state is referenced.
28 
ProgramStateRetain(const ProgramState * state)29 void ProgramStateRetain(const ProgramState *state) {
30   ++const_cast<ProgramState*>(state)->refCount;
31 }
32 
33 /// Decrement the number of times this state is referenced.
ProgramStateRelease(const ProgramState * state)34 void ProgramStateRelease(const ProgramState *state) {
35   assert(state->refCount > 0);
36   ProgramState *s = const_cast<ProgramState*>(state);
37   if (--s->refCount == 0) {
38     ProgramStateManager &Mgr = s->getStateManager();
39     Mgr.StateSet.RemoveNode(s);
40     s->~ProgramState();
41     Mgr.freeStates.push_back(s);
42   }
43 }
44 }}
45 
ProgramState(ProgramStateManager * mgr,const Environment & env,StoreRef st,GenericDataMap gdm)46 ProgramState::ProgramState(ProgramStateManager *mgr, const Environment& env,
47                  StoreRef st, GenericDataMap gdm)
48   : stateMgr(mgr),
49     Env(env),
50     store(st.getStore()),
51     GDM(gdm),
52     refCount(0) {
53   stateMgr->getStoreManager().incrementReferenceCount(store);
54 }
55 
ProgramState(const ProgramState & RHS)56 ProgramState::ProgramState(const ProgramState &RHS)
57     : llvm::FoldingSetNode(),
58       stateMgr(RHS.stateMgr),
59       Env(RHS.Env),
60       store(RHS.store),
61       GDM(RHS.GDM),
62       refCount(0) {
63   stateMgr->getStoreManager().incrementReferenceCount(store);
64 }
65 
~ProgramState()66 ProgramState::~ProgramState() {
67   if (store)
68     stateMgr->getStoreManager().decrementReferenceCount(store);
69 }
70 
getID() const71 int64_t ProgramState::getID() const {
72   return getStateManager().Alloc.identifyKnownAlignedObject<ProgramState>(this);
73 }
74 
ProgramStateManager(ASTContext & Ctx,StoreManagerCreator CreateSMgr,ConstraintManagerCreator CreateCMgr,llvm::BumpPtrAllocator & alloc,ExprEngine * ExprEng)75 ProgramStateManager::ProgramStateManager(ASTContext &Ctx,
76                                          StoreManagerCreator CreateSMgr,
77                                          ConstraintManagerCreator CreateCMgr,
78                                          llvm::BumpPtrAllocator &alloc,
79                                          ExprEngine *ExprEng)
80   : Eng(ExprEng), EnvMgr(alloc), GDMFactory(alloc),
81     svalBuilder(createSimpleSValBuilder(alloc, Ctx, *this)),
82     CallEventMgr(new CallEventManager(alloc)), Alloc(alloc) {
83   StoreMgr = (*CreateSMgr)(*this);
84   ConstraintMgr = (*CreateCMgr)(*this, ExprEng);
85 }
86 
87 
~ProgramStateManager()88 ProgramStateManager::~ProgramStateManager() {
89   for (GDMContextsTy::iterator I=GDMContexts.begin(), E=GDMContexts.end();
90        I!=E; ++I)
91     I->second.second(I->second.first);
92 }
93 
removeDeadBindingsFromEnvironmentAndStore(ProgramStateRef state,const StackFrameContext * LCtx,SymbolReaper & SymReaper)94 ProgramStateRef ProgramStateManager::removeDeadBindingsFromEnvironmentAndStore(
95     ProgramStateRef state, const StackFrameContext *LCtx,
96     SymbolReaper &SymReaper) {
97 
98   // This code essentially performs a "mark-and-sweep" of the VariableBindings.
99   // The roots are any Block-level exprs and Decls that our liveness algorithm
100   // tells us are live.  We then see what Decls they may reference, and keep
101   // those around.  This code more than likely can be made faster, and the
102   // frequency of which this method is called should be experimented with
103   // for optimum performance.
104   ProgramState NewState = *state;
105 
106   NewState.Env = EnvMgr.removeDeadBindings(NewState.Env, SymReaper, state);
107 
108   // Clean up the store.
109   StoreRef newStore = StoreMgr->removeDeadBindings(NewState.getStore(), LCtx,
110                                                    SymReaper);
111   NewState.setStore(newStore);
112   SymReaper.setReapedStore(newStore);
113 
114   return getPersistentState(NewState);
115 }
116 
bindLoc(Loc LV,SVal V,const LocationContext * LCtx,bool notifyChanges) const117 ProgramStateRef ProgramState::bindLoc(Loc LV,
118                                       SVal V,
119                                       const LocationContext *LCtx,
120                                       bool notifyChanges) const {
121   ProgramStateManager &Mgr = getStateManager();
122   ProgramStateRef newState = makeWithStore(Mgr.StoreMgr->Bind(getStore(),
123                                                              LV, V));
124   const MemRegion *MR = LV.getAsRegion();
125   if (MR && notifyChanges)
126     return Mgr.getOwningEngine().processRegionChange(newState, MR, LCtx);
127 
128   return newState;
129 }
130 
131 ProgramStateRef
bindDefaultInitial(SVal loc,SVal V,const LocationContext * LCtx) const132 ProgramState::bindDefaultInitial(SVal loc, SVal V,
133                                  const LocationContext *LCtx) const {
134   ProgramStateManager &Mgr = getStateManager();
135   const MemRegion *R = loc.castAs<loc::MemRegionVal>().getRegion();
136   const StoreRef &newStore = Mgr.StoreMgr->BindDefaultInitial(getStore(), R, V);
137   ProgramStateRef new_state = makeWithStore(newStore);
138   return Mgr.getOwningEngine().processRegionChange(new_state, R, LCtx);
139 }
140 
141 ProgramStateRef
bindDefaultZero(SVal loc,const LocationContext * LCtx) const142 ProgramState::bindDefaultZero(SVal loc, const LocationContext *LCtx) const {
143   ProgramStateManager &Mgr = getStateManager();
144   const MemRegion *R = loc.castAs<loc::MemRegionVal>().getRegion();
145   const StoreRef &newStore = Mgr.StoreMgr->BindDefaultZero(getStore(), R);
146   ProgramStateRef new_state = makeWithStore(newStore);
147   return Mgr.getOwningEngine().processRegionChange(new_state, R, LCtx);
148 }
149 
150 typedef ArrayRef<const MemRegion *> RegionList;
151 typedef ArrayRef<SVal> ValueList;
152 
153 ProgramStateRef
invalidateRegions(RegionList Regions,const Expr * E,unsigned Count,const LocationContext * LCtx,bool CausedByPointerEscape,InvalidatedSymbols * IS,const CallEvent * Call,RegionAndSymbolInvalidationTraits * ITraits) const154 ProgramState::invalidateRegions(RegionList Regions,
155                              const Expr *E, unsigned Count,
156                              const LocationContext *LCtx,
157                              bool CausedByPointerEscape,
158                              InvalidatedSymbols *IS,
159                              const CallEvent *Call,
160                              RegionAndSymbolInvalidationTraits *ITraits) const {
161   SmallVector<SVal, 8> Values;
162   for (RegionList::const_iterator I = Regions.begin(),
163                                   End = Regions.end(); I != End; ++I)
164     Values.push_back(loc::MemRegionVal(*I));
165 
166   return invalidateRegionsImpl(Values, E, Count, LCtx, CausedByPointerEscape,
167                                IS, ITraits, Call);
168 }
169 
170 ProgramStateRef
invalidateRegions(ValueList Values,const Expr * E,unsigned Count,const LocationContext * LCtx,bool CausedByPointerEscape,InvalidatedSymbols * IS,const CallEvent * Call,RegionAndSymbolInvalidationTraits * ITraits) const171 ProgramState::invalidateRegions(ValueList Values,
172                              const Expr *E, unsigned Count,
173                              const LocationContext *LCtx,
174                              bool CausedByPointerEscape,
175                              InvalidatedSymbols *IS,
176                              const CallEvent *Call,
177                              RegionAndSymbolInvalidationTraits *ITraits) const {
178 
179   return invalidateRegionsImpl(Values, E, Count, LCtx, CausedByPointerEscape,
180                                IS, ITraits, Call);
181 }
182 
183 ProgramStateRef
invalidateRegionsImpl(ValueList Values,const Expr * E,unsigned Count,const LocationContext * LCtx,bool CausedByPointerEscape,InvalidatedSymbols * IS,RegionAndSymbolInvalidationTraits * ITraits,const CallEvent * Call) const184 ProgramState::invalidateRegionsImpl(ValueList Values,
185                                     const Expr *E, unsigned Count,
186                                     const LocationContext *LCtx,
187                                     bool CausedByPointerEscape,
188                                     InvalidatedSymbols *IS,
189                                     RegionAndSymbolInvalidationTraits *ITraits,
190                                     const CallEvent *Call) const {
191   ProgramStateManager &Mgr = getStateManager();
192   ExprEngine &Eng = Mgr.getOwningEngine();
193 
194   InvalidatedSymbols InvalidatedSyms;
195   if (!IS)
196     IS = &InvalidatedSyms;
197 
198   RegionAndSymbolInvalidationTraits ITraitsLocal;
199   if (!ITraits)
200     ITraits = &ITraitsLocal;
201 
202   StoreManager::InvalidatedRegions TopLevelInvalidated;
203   StoreManager::InvalidatedRegions Invalidated;
204   const StoreRef &newStore
205   = Mgr.StoreMgr->invalidateRegions(getStore(), Values, E, Count, LCtx, Call,
206                                     *IS, *ITraits, &TopLevelInvalidated,
207                                     &Invalidated);
208 
209   ProgramStateRef newState = makeWithStore(newStore);
210 
211   if (CausedByPointerEscape) {
212     newState = Eng.notifyCheckersOfPointerEscape(newState, IS,
213                                                  TopLevelInvalidated,
214                                                  Call,
215                                                  *ITraits);
216   }
217 
218   return Eng.processRegionChanges(newState, IS, TopLevelInvalidated,
219                                   Invalidated, LCtx, Call);
220 }
221 
killBinding(Loc LV) const222 ProgramStateRef ProgramState::killBinding(Loc LV) const {
223   assert(!LV.getAs<loc::MemRegionVal>() && "Use invalidateRegion instead.");
224 
225   Store OldStore = getStore();
226   const StoreRef &newStore =
227     getStateManager().StoreMgr->killBinding(OldStore, LV);
228 
229   if (newStore.getStore() == OldStore)
230     return this;
231 
232   return makeWithStore(newStore);
233 }
234 
235 ProgramStateRef
enterStackFrame(const CallEvent & Call,const StackFrameContext * CalleeCtx) const236 ProgramState::enterStackFrame(const CallEvent &Call,
237                               const StackFrameContext *CalleeCtx) const {
238   const StoreRef &NewStore =
239     getStateManager().StoreMgr->enterStackFrame(getStore(), Call, CalleeCtx);
240   return makeWithStore(NewStore);
241 }
242 
getSelfSVal(const LocationContext * LCtx) const243 SVal ProgramState::getSelfSVal(const LocationContext *LCtx) const {
244   const ImplicitParamDecl *SelfDecl = LCtx->getSelfDecl();
245   if (!SelfDecl)
246     return SVal();
247   return getSVal(getRegion(SelfDecl, LCtx));
248 }
249 
getSValAsScalarOrLoc(const MemRegion * R) const250 SVal ProgramState::getSValAsScalarOrLoc(const MemRegion *R) const {
251   // We only want to do fetches from regions that we can actually bind
252   // values.  For example, SymbolicRegions of type 'id<...>' cannot
253   // have direct bindings (but their can be bindings on their subregions).
254   if (!R->isBoundable())
255     return UnknownVal();
256 
257   if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) {
258     QualType T = TR->getValueType();
259     if (Loc::isLocType(T) || T->isIntegralOrEnumerationType())
260       return getSVal(R);
261   }
262 
263   return UnknownVal();
264 }
265 
getSVal(Loc location,QualType T) const266 SVal ProgramState::getSVal(Loc location, QualType T) const {
267   SVal V = getRawSVal(location, T);
268 
269   // If 'V' is a symbolic value that is *perfectly* constrained to
270   // be a constant value, use that value instead to lessen the burden
271   // on later analysis stages (so we have less symbolic values to reason
272   // about).
273   // We only go into this branch if we can convert the APSInt value we have
274   // to the type of T, which is not always the case (e.g. for void).
275   if (!T.isNull() && (T->isIntegralOrEnumerationType() || Loc::isLocType(T))) {
276     if (SymbolRef sym = V.getAsSymbol()) {
277       if (const llvm::APSInt *Int = getStateManager()
278                                     .getConstraintManager()
279                                     .getSymVal(this, sym)) {
280         // FIXME: Because we don't correctly model (yet) sign-extension
281         // and truncation of symbolic values, we need to convert
282         // the integer value to the correct signedness and bitwidth.
283         //
284         // This shows up in the following:
285         //
286         //   char foo();
287         //   unsigned x = foo();
288         //   if (x == 54)
289         //     ...
290         //
291         //  The symbolic value stored to 'x' is actually the conjured
292         //  symbol for the call to foo(); the type of that symbol is 'char',
293         //  not unsigned.
294         const llvm::APSInt &NewV = getBasicVals().Convert(T, *Int);
295 
296         if (V.getAs<Loc>())
297           return loc::ConcreteInt(NewV);
298         else
299           return nonloc::ConcreteInt(NewV);
300       }
301     }
302   }
303 
304   return V;
305 }
306 
BindExpr(const Stmt * S,const LocationContext * LCtx,SVal V,bool Invalidate) const307 ProgramStateRef ProgramState::BindExpr(const Stmt *S,
308                                            const LocationContext *LCtx,
309                                            SVal V, bool Invalidate) const{
310   Environment NewEnv =
311     getStateManager().EnvMgr.bindExpr(Env, EnvironmentEntry(S, LCtx), V,
312                                       Invalidate);
313   if (NewEnv == Env)
314     return this;
315 
316   ProgramState NewSt = *this;
317   NewSt.Env = NewEnv;
318   return getStateManager().getPersistentState(NewSt);
319 }
320 
assumeInBound(DefinedOrUnknownSVal Idx,DefinedOrUnknownSVal UpperBound,bool Assumption,QualType indexTy) const321 ProgramStateRef ProgramState::assumeInBound(DefinedOrUnknownSVal Idx,
322                                       DefinedOrUnknownSVal UpperBound,
323                                       bool Assumption,
324                                       QualType indexTy) const {
325   if (Idx.isUnknown() || UpperBound.isUnknown())
326     return this;
327 
328   // Build an expression for 0 <= Idx < UpperBound.
329   // This is the same as Idx + MIN < UpperBound + MIN, if overflow is allowed.
330   // FIXME: This should probably be part of SValBuilder.
331   ProgramStateManager &SM = getStateManager();
332   SValBuilder &svalBuilder = SM.getSValBuilder();
333   ASTContext &Ctx = svalBuilder.getContext();
334 
335   // Get the offset: the minimum value of the array index type.
336   BasicValueFactory &BVF = svalBuilder.getBasicValueFactory();
337   if (indexTy.isNull())
338     indexTy = svalBuilder.getArrayIndexType();
339   nonloc::ConcreteInt Min(BVF.getMinValue(indexTy));
340 
341   // Adjust the index.
342   SVal newIdx = svalBuilder.evalBinOpNN(this, BO_Add,
343                                         Idx.castAs<NonLoc>(), Min, indexTy);
344   if (newIdx.isUnknownOrUndef())
345     return this;
346 
347   // Adjust the upper bound.
348   SVal newBound =
349     svalBuilder.evalBinOpNN(this, BO_Add, UpperBound.castAs<NonLoc>(),
350                             Min, indexTy);
351 
352   if (newBound.isUnknownOrUndef())
353     return this;
354 
355   // Build the actual comparison.
356   SVal inBound = svalBuilder.evalBinOpNN(this, BO_LT, newIdx.castAs<NonLoc>(),
357                                          newBound.castAs<NonLoc>(), Ctx.IntTy);
358   if (inBound.isUnknownOrUndef())
359     return this;
360 
361   // Finally, let the constraint manager take care of it.
362   ConstraintManager &CM = SM.getConstraintManager();
363   return CM.assume(this, inBound.castAs<DefinedSVal>(), Assumption);
364 }
365 
isNonNull(SVal V) const366 ConditionTruthVal ProgramState::isNonNull(SVal V) const {
367   ConditionTruthVal IsNull = isNull(V);
368   if (IsNull.isUnderconstrained())
369     return IsNull;
370   return ConditionTruthVal(!IsNull.getValue());
371 }
372 
areEqual(SVal Lhs,SVal Rhs) const373 ConditionTruthVal ProgramState::areEqual(SVal Lhs, SVal Rhs) const {
374   return stateMgr->getSValBuilder().areEqual(this, Lhs, Rhs);
375 }
376 
isNull(SVal V) const377 ConditionTruthVal ProgramState::isNull(SVal V) const {
378   if (V.isZeroConstant())
379     return true;
380 
381   if (V.isConstant())
382     return false;
383 
384   SymbolRef Sym = V.getAsSymbol(/* IncludeBaseRegion */ true);
385   if (!Sym)
386     return ConditionTruthVal();
387 
388   return getStateManager().ConstraintMgr->isNull(this, Sym);
389 }
390 
getInitialState(const LocationContext * InitLoc)391 ProgramStateRef ProgramStateManager::getInitialState(const LocationContext *InitLoc) {
392   ProgramState State(this,
393                 EnvMgr.getInitialEnvironment(),
394                 StoreMgr->getInitialStore(InitLoc),
395                 GDMFactory.getEmptyMap());
396 
397   return getPersistentState(State);
398 }
399 
getPersistentStateWithGDM(ProgramStateRef FromState,ProgramStateRef GDMState)400 ProgramStateRef ProgramStateManager::getPersistentStateWithGDM(
401                                                      ProgramStateRef FromState,
402                                                      ProgramStateRef GDMState) {
403   ProgramState NewState(*FromState);
404   NewState.GDM = GDMState->GDM;
405   return getPersistentState(NewState);
406 }
407 
getPersistentState(ProgramState & State)408 ProgramStateRef ProgramStateManager::getPersistentState(ProgramState &State) {
409 
410   llvm::FoldingSetNodeID ID;
411   State.Profile(ID);
412   void *InsertPos;
413 
414   if (ProgramState *I = StateSet.FindNodeOrInsertPos(ID, InsertPos))
415     return I;
416 
417   ProgramState *newState = nullptr;
418   if (!freeStates.empty()) {
419     newState = freeStates.back();
420     freeStates.pop_back();
421   }
422   else {
423     newState = (ProgramState*) Alloc.Allocate<ProgramState>();
424   }
425   new (newState) ProgramState(State);
426   StateSet.InsertNode(newState, InsertPos);
427   return newState;
428 }
429 
makeWithStore(const StoreRef & store) const430 ProgramStateRef ProgramState::makeWithStore(const StoreRef &store) const {
431   ProgramState NewSt(*this);
432   NewSt.setStore(store);
433   return getStateManager().getPersistentState(NewSt);
434 }
435 
setStore(const StoreRef & newStore)436 void ProgramState::setStore(const StoreRef &newStore) {
437   Store newStoreStore = newStore.getStore();
438   if (newStoreStore)
439     stateMgr->getStoreManager().incrementReferenceCount(newStoreStore);
440   if (store)
441     stateMgr->getStoreManager().decrementReferenceCount(store);
442   store = newStoreStore;
443 }
444 
445 //===----------------------------------------------------------------------===//
446 //  State pretty-printing.
447 //===----------------------------------------------------------------------===//
448 
printJson(raw_ostream & Out,const LocationContext * LCtx,const char * NL,unsigned int Space,bool IsDot) const449 void ProgramState::printJson(raw_ostream &Out, const LocationContext *LCtx,
450                              const char *NL, unsigned int Space,
451                              bool IsDot) const {
452   Indent(Out, Space, IsDot) << "\"program_state\": {" << NL;
453   ++Space;
454 
455   ProgramStateManager &Mgr = getStateManager();
456 
457   // Print the store.
458   Mgr.getStoreManager().printJson(Out, getStore(), NL, Space, IsDot);
459 
460   // Print out the environment.
461   Env.printJson(Out, Mgr.getContext(), LCtx, NL, Space, IsDot);
462 
463   // Print out the constraints.
464   Mgr.getConstraintManager().printJson(Out, this, NL, Space, IsDot);
465 
466   // Print out the tracked dynamic types.
467   printDynamicTypeInfoJson(Out, this, NL, Space, IsDot);
468 
469   // Print checker-specific data.
470   Mgr.getOwningEngine().printJson(Out, this, LCtx, NL, Space, IsDot);
471 
472   --Space;
473   Indent(Out, Space, IsDot) << '}';
474 }
475 
printDOT(raw_ostream & Out,const LocationContext * LCtx,unsigned int Space) const476 void ProgramState::printDOT(raw_ostream &Out, const LocationContext *LCtx,
477                             unsigned int Space) const {
478   printJson(Out, LCtx, /*NL=*/"\\l", Space, /*IsDot=*/true);
479 }
480 
dump() const481 LLVM_DUMP_METHOD void ProgramState::dump() const {
482   printJson(llvm::errs());
483 }
484 
getAnalysisManager() const485 AnalysisManager& ProgramState::getAnalysisManager() const {
486   return stateMgr->getOwningEngine().getAnalysisManager();
487 }
488 
489 //===----------------------------------------------------------------------===//
490 // Generic Data Map.
491 //===----------------------------------------------------------------------===//
492 
FindGDM(void * K) const493 void *const* ProgramState::FindGDM(void *K) const {
494   return GDM.lookup(K);
495 }
496 
497 void*
FindGDMContext(void * K,void * (* CreateContext)(llvm::BumpPtrAllocator &),void (* DeleteContext)(void *))498 ProgramStateManager::FindGDMContext(void *K,
499                                void *(*CreateContext)(llvm::BumpPtrAllocator&),
500                                void (*DeleteContext)(void*)) {
501 
502   std::pair<void*, void (*)(void*)>& p = GDMContexts[K];
503   if (!p.first) {
504     p.first = CreateContext(Alloc);
505     p.second = DeleteContext;
506   }
507 
508   return p.first;
509 }
510 
addGDM(ProgramStateRef St,void * Key,void * Data)511 ProgramStateRef ProgramStateManager::addGDM(ProgramStateRef St, void *Key, void *Data){
512   ProgramState::GenericDataMap M1 = St->getGDM();
513   ProgramState::GenericDataMap M2 = GDMFactory.add(M1, Key, Data);
514 
515   if (M1 == M2)
516     return St;
517 
518   ProgramState NewSt = *St;
519   NewSt.GDM = M2;
520   return getPersistentState(NewSt);
521 }
522 
removeGDM(ProgramStateRef state,void * Key)523 ProgramStateRef ProgramStateManager::removeGDM(ProgramStateRef state, void *Key) {
524   ProgramState::GenericDataMap OldM = state->getGDM();
525   ProgramState::GenericDataMap NewM = GDMFactory.remove(OldM, Key);
526 
527   if (NewM == OldM)
528     return state;
529 
530   ProgramState NewState = *state;
531   NewState.GDM = NewM;
532   return getPersistentState(NewState);
533 }
534 
scan(nonloc::LazyCompoundVal val)535 bool ScanReachableSymbols::scan(nonloc::LazyCompoundVal val) {
536   bool wasVisited = !visited.insert(val.getCVData()).second;
537   if (wasVisited)
538     return true;
539 
540   StoreManager &StoreMgr = state->getStateManager().getStoreManager();
541   // FIXME: We don't really want to use getBaseRegion() here because pointer
542   // arithmetic doesn't apply, but scanReachableSymbols only accepts base
543   // regions right now.
544   const MemRegion *R = val.getRegion()->getBaseRegion();
545   return StoreMgr.scanReachableSymbols(val.getStore(), R, *this);
546 }
547 
scan(nonloc::CompoundVal val)548 bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
549   for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I)
550     if (!scan(*I))
551       return false;
552 
553   return true;
554 }
555 
scan(const SymExpr * sym)556 bool ScanReachableSymbols::scan(const SymExpr *sym) {
557   for (SymExpr::symbol_iterator SI = sym->symbol_begin(),
558                                 SE = sym->symbol_end();
559        SI != SE; ++SI) {
560     bool wasVisited = !visited.insert(*SI).second;
561     if (wasVisited)
562       continue;
563 
564     if (!visitor.VisitSymbol(*SI))
565       return false;
566   }
567 
568   return true;
569 }
570 
scan(SVal val)571 bool ScanReachableSymbols::scan(SVal val) {
572   if (Optional<loc::MemRegionVal> X = val.getAs<loc::MemRegionVal>())
573     return scan(X->getRegion());
574 
575   if (Optional<nonloc::LazyCompoundVal> X =
576           val.getAs<nonloc::LazyCompoundVal>())
577     return scan(*X);
578 
579   if (Optional<nonloc::LocAsInteger> X = val.getAs<nonloc::LocAsInteger>())
580     return scan(X->getLoc());
581 
582   if (SymbolRef Sym = val.getAsSymbol())
583     return scan(Sym);
584 
585   if (Optional<nonloc::CompoundVal> X = val.getAs<nonloc::CompoundVal>())
586     return scan(*X);
587 
588   return true;
589 }
590 
scan(const MemRegion * R)591 bool ScanReachableSymbols::scan(const MemRegion *R) {
592   if (isa<MemSpaceRegion>(R))
593     return true;
594 
595   bool wasVisited = !visited.insert(R).second;
596   if (wasVisited)
597     return true;
598 
599   if (!visitor.VisitMemRegion(R))
600     return false;
601 
602   // If this is a symbolic region, visit the symbol for the region.
603   if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
604     if (!visitor.VisitSymbol(SR->getSymbol()))
605       return false;
606 
607   // If this is a subregion, also visit the parent regions.
608   if (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
609     const MemRegion *Super = SR->getSuperRegion();
610     if (!scan(Super))
611       return false;
612 
613     // When we reach the topmost region, scan all symbols in it.
614     if (isa<MemSpaceRegion>(Super)) {
615       StoreManager &StoreMgr = state->getStateManager().getStoreManager();
616       if (!StoreMgr.scanReachableSymbols(state->getStore(), SR, *this))
617         return false;
618     }
619   }
620 
621   // Regions captured by a block are also implicitly reachable.
622   if (const BlockDataRegion *BDR = dyn_cast<BlockDataRegion>(R)) {
623     BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
624                                               E = BDR->referenced_vars_end();
625     for ( ; I != E; ++I) {
626       if (!scan(I.getCapturedRegion()))
627         return false;
628     }
629   }
630 
631   return true;
632 }
633 
scanReachableSymbols(SVal val,SymbolVisitor & visitor) const634 bool ProgramState::scanReachableSymbols(SVal val, SymbolVisitor& visitor) const {
635   ScanReachableSymbols S(this, visitor);
636   return S.scan(val);
637 }
638 
scanReachableSymbols(llvm::iterator_range<region_iterator> Reachable,SymbolVisitor & visitor) const639 bool ProgramState::scanReachableSymbols(
640     llvm::iterator_range<region_iterator> Reachable,
641     SymbolVisitor &visitor) const {
642   ScanReachableSymbols S(this, visitor);
643   for (const MemRegion *R : Reachable) {
644     if (!S.scan(R))
645       return false;
646   }
647   return true;
648 }
649