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/ProgramStateTrait.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.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,SubEngine * SubEng)75 ProgramStateManager::ProgramStateManager(ASTContext &Ctx,
76 StoreManagerCreator CreateSMgr,
77 ConstraintManagerCreator CreateCMgr,
78 llvm::BumpPtrAllocator &alloc,
79 SubEngine *SubEng)
80 : Eng(SubEng), 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, SubEng);
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 SubEngine &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
getSValAsScalarOrLoc(const MemRegion * R) const243 SVal ProgramState::getSValAsScalarOrLoc(const MemRegion *R) const {
244 // We only want to do fetches from regions that we can actually bind
245 // values. For example, SymbolicRegions of type 'id<...>' cannot
246 // have direct bindings (but their can be bindings on their subregions).
247 if (!R->isBoundable())
248 return UnknownVal();
249
250 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) {
251 QualType T = TR->getValueType();
252 if (Loc::isLocType(T) || T->isIntegralOrEnumerationType())
253 return getSVal(R);
254 }
255
256 return UnknownVal();
257 }
258
getSVal(Loc location,QualType T) const259 SVal ProgramState::getSVal(Loc location, QualType T) const {
260 SVal V = getRawSVal(location, T);
261
262 // If 'V' is a symbolic value that is *perfectly* constrained to
263 // be a constant value, use that value instead to lessen the burden
264 // on later analysis stages (so we have less symbolic values to reason
265 // about).
266 // We only go into this branch if we can convert the APSInt value we have
267 // to the type of T, which is not always the case (e.g. for void).
268 if (!T.isNull() && (T->isIntegralOrEnumerationType() || Loc::isLocType(T))) {
269 if (SymbolRef sym = V.getAsSymbol()) {
270 if (const llvm::APSInt *Int = getStateManager()
271 .getConstraintManager()
272 .getSymVal(this, sym)) {
273 // FIXME: Because we don't correctly model (yet) sign-extension
274 // and truncation of symbolic values, we need to convert
275 // the integer value to the correct signedness and bitwidth.
276 //
277 // This shows up in the following:
278 //
279 // char foo();
280 // unsigned x = foo();
281 // if (x == 54)
282 // ...
283 //
284 // The symbolic value stored to 'x' is actually the conjured
285 // symbol for the call to foo(); the type of that symbol is 'char',
286 // not unsigned.
287 const llvm::APSInt &NewV = getBasicVals().Convert(T, *Int);
288
289 if (V.getAs<Loc>())
290 return loc::ConcreteInt(NewV);
291 else
292 return nonloc::ConcreteInt(NewV);
293 }
294 }
295 }
296
297 return V;
298 }
299
BindExpr(const Stmt * S,const LocationContext * LCtx,SVal V,bool Invalidate) const300 ProgramStateRef ProgramState::BindExpr(const Stmt *S,
301 const LocationContext *LCtx,
302 SVal V, bool Invalidate) const{
303 Environment NewEnv =
304 getStateManager().EnvMgr.bindExpr(Env, EnvironmentEntry(S, LCtx), V,
305 Invalidate);
306 if (NewEnv == Env)
307 return this;
308
309 ProgramState NewSt = *this;
310 NewSt.Env = NewEnv;
311 return getStateManager().getPersistentState(NewSt);
312 }
313
assumeInBound(DefinedOrUnknownSVal Idx,DefinedOrUnknownSVal UpperBound,bool Assumption,QualType indexTy) const314 ProgramStateRef ProgramState::assumeInBound(DefinedOrUnknownSVal Idx,
315 DefinedOrUnknownSVal UpperBound,
316 bool Assumption,
317 QualType indexTy) const {
318 if (Idx.isUnknown() || UpperBound.isUnknown())
319 return this;
320
321 // Build an expression for 0 <= Idx < UpperBound.
322 // This is the same as Idx + MIN < UpperBound + MIN, if overflow is allowed.
323 // FIXME: This should probably be part of SValBuilder.
324 ProgramStateManager &SM = getStateManager();
325 SValBuilder &svalBuilder = SM.getSValBuilder();
326 ASTContext &Ctx = svalBuilder.getContext();
327
328 // Get the offset: the minimum value of the array index type.
329 BasicValueFactory &BVF = svalBuilder.getBasicValueFactory();
330 if (indexTy.isNull())
331 indexTy = svalBuilder.getArrayIndexType();
332 nonloc::ConcreteInt Min(BVF.getMinValue(indexTy));
333
334 // Adjust the index.
335 SVal newIdx = svalBuilder.evalBinOpNN(this, BO_Add,
336 Idx.castAs<NonLoc>(), Min, indexTy);
337 if (newIdx.isUnknownOrUndef())
338 return this;
339
340 // Adjust the upper bound.
341 SVal newBound =
342 svalBuilder.evalBinOpNN(this, BO_Add, UpperBound.castAs<NonLoc>(),
343 Min, indexTy);
344
345 if (newBound.isUnknownOrUndef())
346 return this;
347
348 // Build the actual comparison.
349 SVal inBound = svalBuilder.evalBinOpNN(this, BO_LT, newIdx.castAs<NonLoc>(),
350 newBound.castAs<NonLoc>(), Ctx.IntTy);
351 if (inBound.isUnknownOrUndef())
352 return this;
353
354 // Finally, let the constraint manager take care of it.
355 ConstraintManager &CM = SM.getConstraintManager();
356 return CM.assume(this, inBound.castAs<DefinedSVal>(), Assumption);
357 }
358
isNonNull(SVal V) const359 ConditionTruthVal ProgramState::isNonNull(SVal V) const {
360 ConditionTruthVal IsNull = isNull(V);
361 if (IsNull.isUnderconstrained())
362 return IsNull;
363 return ConditionTruthVal(!IsNull.getValue());
364 }
365
areEqual(SVal Lhs,SVal Rhs) const366 ConditionTruthVal ProgramState::areEqual(SVal Lhs, SVal Rhs) const {
367 return stateMgr->getSValBuilder().areEqual(this, Lhs, Rhs);
368 }
369
isNull(SVal V) const370 ConditionTruthVal ProgramState::isNull(SVal V) const {
371 if (V.isZeroConstant())
372 return true;
373
374 if (V.isConstant())
375 return false;
376
377 SymbolRef Sym = V.getAsSymbol(/* IncludeBaseRegion */ true);
378 if (!Sym)
379 return ConditionTruthVal();
380
381 return getStateManager().ConstraintMgr->isNull(this, Sym);
382 }
383
getInitialState(const LocationContext * InitLoc)384 ProgramStateRef ProgramStateManager::getInitialState(const LocationContext *InitLoc) {
385 ProgramState State(this,
386 EnvMgr.getInitialEnvironment(),
387 StoreMgr->getInitialStore(InitLoc),
388 GDMFactory.getEmptyMap());
389
390 return getPersistentState(State);
391 }
392
getPersistentStateWithGDM(ProgramStateRef FromState,ProgramStateRef GDMState)393 ProgramStateRef ProgramStateManager::getPersistentStateWithGDM(
394 ProgramStateRef FromState,
395 ProgramStateRef GDMState) {
396 ProgramState NewState(*FromState);
397 NewState.GDM = GDMState->GDM;
398 return getPersistentState(NewState);
399 }
400
getPersistentState(ProgramState & State)401 ProgramStateRef ProgramStateManager::getPersistentState(ProgramState &State) {
402
403 llvm::FoldingSetNodeID ID;
404 State.Profile(ID);
405 void *InsertPos;
406
407 if (ProgramState *I = StateSet.FindNodeOrInsertPos(ID, InsertPos))
408 return I;
409
410 ProgramState *newState = nullptr;
411 if (!freeStates.empty()) {
412 newState = freeStates.back();
413 freeStates.pop_back();
414 }
415 else {
416 newState = (ProgramState*) Alloc.Allocate<ProgramState>();
417 }
418 new (newState) ProgramState(State);
419 StateSet.InsertNode(newState, InsertPos);
420 return newState;
421 }
422
makeWithStore(const StoreRef & store) const423 ProgramStateRef ProgramState::makeWithStore(const StoreRef &store) const {
424 ProgramState NewSt(*this);
425 NewSt.setStore(store);
426 return getStateManager().getPersistentState(NewSt);
427 }
428
setStore(const StoreRef & newStore)429 void ProgramState::setStore(const StoreRef &newStore) {
430 Store newStoreStore = newStore.getStore();
431 if (newStoreStore)
432 stateMgr->getStoreManager().incrementReferenceCount(newStoreStore);
433 if (store)
434 stateMgr->getStoreManager().decrementReferenceCount(store);
435 store = newStoreStore;
436 }
437
438 //===----------------------------------------------------------------------===//
439 // State pretty-printing.
440 //===----------------------------------------------------------------------===//
441
printJson(raw_ostream & Out,const LocationContext * LCtx,const char * NL,unsigned int Space,bool IsDot) const442 void ProgramState::printJson(raw_ostream &Out, const LocationContext *LCtx,
443 const char *NL, unsigned int Space,
444 bool IsDot) const {
445 Indent(Out, Space, IsDot) << "\"program_state\": {" << NL;
446 ++Space;
447
448 ProgramStateManager &Mgr = getStateManager();
449
450 // Print the store.
451 Mgr.getStoreManager().printJson(Out, getStore(), NL, Space, IsDot);
452
453 // Print out the environment.
454 Env.printJson(Out, Mgr.getContext(), LCtx, NL, Space, IsDot);
455
456 // Print out the constraints.
457 Mgr.getConstraintManager().printJson(Out, this, NL, Space, IsDot);
458
459 // Print out the tracked dynamic types.
460 printDynamicTypeInfoJson(Out, this, NL, Space, IsDot);
461
462 // Print checker-specific data.
463 Mgr.getOwningEngine().printJson(Out, this, LCtx, NL, Space, IsDot);
464
465 --Space;
466 Indent(Out, Space, IsDot) << '}';
467 }
468
printDOT(raw_ostream & Out,const LocationContext * LCtx,unsigned int Space) const469 void ProgramState::printDOT(raw_ostream &Out, const LocationContext *LCtx,
470 unsigned int Space) const {
471 printJson(Out, LCtx, /*NL=*/"\\l", Space, /*IsDot=*/true);
472 }
473
dump() const474 LLVM_DUMP_METHOD void ProgramState::dump() const {
475 printJson(llvm::errs());
476 }
477
getAnalysisManager() const478 AnalysisManager& ProgramState::getAnalysisManager() const {
479 return stateMgr->getOwningEngine().getAnalysisManager();
480 }
481
482 //===----------------------------------------------------------------------===//
483 // Generic Data Map.
484 //===----------------------------------------------------------------------===//
485
FindGDM(void * K) const486 void *const* ProgramState::FindGDM(void *K) const {
487 return GDM.lookup(K);
488 }
489
490 void*
FindGDMContext(void * K,void * (* CreateContext)(llvm::BumpPtrAllocator &),void (* DeleteContext)(void *))491 ProgramStateManager::FindGDMContext(void *K,
492 void *(*CreateContext)(llvm::BumpPtrAllocator&),
493 void (*DeleteContext)(void*)) {
494
495 std::pair<void*, void (*)(void*)>& p = GDMContexts[K];
496 if (!p.first) {
497 p.first = CreateContext(Alloc);
498 p.second = DeleteContext;
499 }
500
501 return p.first;
502 }
503
addGDM(ProgramStateRef St,void * Key,void * Data)504 ProgramStateRef ProgramStateManager::addGDM(ProgramStateRef St, void *Key, void *Data){
505 ProgramState::GenericDataMap M1 = St->getGDM();
506 ProgramState::GenericDataMap M2 = GDMFactory.add(M1, Key, Data);
507
508 if (M1 == M2)
509 return St;
510
511 ProgramState NewSt = *St;
512 NewSt.GDM = M2;
513 return getPersistentState(NewSt);
514 }
515
removeGDM(ProgramStateRef state,void * Key)516 ProgramStateRef ProgramStateManager::removeGDM(ProgramStateRef state, void *Key) {
517 ProgramState::GenericDataMap OldM = state->getGDM();
518 ProgramState::GenericDataMap NewM = GDMFactory.remove(OldM, Key);
519
520 if (NewM == OldM)
521 return state;
522
523 ProgramState NewState = *state;
524 NewState.GDM = NewM;
525 return getPersistentState(NewState);
526 }
527
scan(nonloc::LazyCompoundVal val)528 bool ScanReachableSymbols::scan(nonloc::LazyCompoundVal val) {
529 bool wasVisited = !visited.insert(val.getCVData()).second;
530 if (wasVisited)
531 return true;
532
533 StoreManager &StoreMgr = state->getStateManager().getStoreManager();
534 // FIXME: We don't really want to use getBaseRegion() here because pointer
535 // arithmetic doesn't apply, but scanReachableSymbols only accepts base
536 // regions right now.
537 const MemRegion *R = val.getRegion()->getBaseRegion();
538 return StoreMgr.scanReachableSymbols(val.getStore(), R, *this);
539 }
540
scan(nonloc::CompoundVal val)541 bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
542 for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I)
543 if (!scan(*I))
544 return false;
545
546 return true;
547 }
548
scan(const SymExpr * sym)549 bool ScanReachableSymbols::scan(const SymExpr *sym) {
550 for (SymExpr::symbol_iterator SI = sym->symbol_begin(),
551 SE = sym->symbol_end();
552 SI != SE; ++SI) {
553 bool wasVisited = !visited.insert(*SI).second;
554 if (wasVisited)
555 continue;
556
557 if (!visitor.VisitSymbol(*SI))
558 return false;
559 }
560
561 return true;
562 }
563
scan(SVal val)564 bool ScanReachableSymbols::scan(SVal val) {
565 if (Optional<loc::MemRegionVal> X = val.getAs<loc::MemRegionVal>())
566 return scan(X->getRegion());
567
568 if (Optional<nonloc::LazyCompoundVal> X =
569 val.getAs<nonloc::LazyCompoundVal>())
570 return scan(*X);
571
572 if (Optional<nonloc::LocAsInteger> X = val.getAs<nonloc::LocAsInteger>())
573 return scan(X->getLoc());
574
575 if (SymbolRef Sym = val.getAsSymbol())
576 return scan(Sym);
577
578 if (const SymExpr *Sym = val.getAsSymbolicExpression())
579 return scan(Sym);
580
581 if (Optional<nonloc::CompoundVal> X = val.getAs<nonloc::CompoundVal>())
582 return scan(*X);
583
584 return true;
585 }
586
scan(const MemRegion * R)587 bool ScanReachableSymbols::scan(const MemRegion *R) {
588 if (isa<MemSpaceRegion>(R))
589 return true;
590
591 bool wasVisited = !visited.insert(R).second;
592 if (wasVisited)
593 return true;
594
595 if (!visitor.VisitMemRegion(R))
596 return false;
597
598 // If this is a symbolic region, visit the symbol for the region.
599 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
600 if (!visitor.VisitSymbol(SR->getSymbol()))
601 return false;
602
603 // If this is a subregion, also visit the parent regions.
604 if (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
605 const MemRegion *Super = SR->getSuperRegion();
606 if (!scan(Super))
607 return false;
608
609 // When we reach the topmost region, scan all symbols in it.
610 if (isa<MemSpaceRegion>(Super)) {
611 StoreManager &StoreMgr = state->getStateManager().getStoreManager();
612 if (!StoreMgr.scanReachableSymbols(state->getStore(), SR, *this))
613 return false;
614 }
615 }
616
617 // Regions captured by a block are also implicitly reachable.
618 if (const BlockDataRegion *BDR = dyn_cast<BlockDataRegion>(R)) {
619 BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
620 E = BDR->referenced_vars_end();
621 for ( ; I != E; ++I) {
622 if (!scan(I.getCapturedRegion()))
623 return false;
624 }
625 }
626
627 return true;
628 }
629
scanReachableSymbols(SVal val,SymbolVisitor & visitor) const630 bool ProgramState::scanReachableSymbols(SVal val, SymbolVisitor& visitor) const {
631 ScanReachableSymbols S(this, visitor);
632 return S.scan(val);
633 }
634
scanReachableSymbols(llvm::iterator_range<region_iterator> Reachable,SymbolVisitor & visitor) const635 bool ProgramState::scanReachableSymbols(
636 llvm::iterator_range<region_iterator> Reachable,
637 SymbolVisitor &visitor) const {
638 ScanReachableSymbols S(this, visitor);
639 for (const MemRegion *R : Reachable) {
640 if (!S.scan(R))
641 return false;
642 }
643 return true;
644 }
645