ProgramState.cpp revision 66c40400e7d6272b0cd675ada18dd62c1f0362c7 
1//= ProgramState.cpp - Path-Sensitive "State" for tracking values --*- 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 implements ProgramState and ProgramStateManager.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Analysis/CFG.h"
15#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
16#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
17#include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h"
18#include "clang/StaticAnalyzer/Core/PathSensitive/TaintManager.h"
19#include "llvm/Support/raw_ostream.h"
20
21using namespace clang;
22using namespace ento;
23
24// Give the vtable for ConstraintManager somewhere to live.
25// FIXME: Move this elsewhere.
26ConstraintManager::~ConstraintManager() {}
27
28namespace clang { namespace  ento {
29/// Increments the number of times this state is referenced.
30
31void ProgramStateRetain(const ProgramState *state) {
32  ++const_cast<ProgramState*>(state)->refCount;
33}
34
35/// Decrement the number of times this state is referenced.
36void ProgramStateRelease(const ProgramState *state) {
37  assert(state->refCount > 0);
38  ProgramState *s = const_cast<ProgramState*>(state);
39  if (--s->refCount == 0) {
40    ProgramStateManager &Mgr = s->getStateManager();
41    Mgr.StateSet.RemoveNode(s);
42    s->~ProgramState();
43    Mgr.freeStates.push_back(s);
44  }
45}
46}}
47
48ProgramState::ProgramState(ProgramStateManager *mgr, const Environment& env,
49                 StoreRef st, GenericDataMap gdm)
50  : stateMgr(mgr),
51    Env(env),
52    store(st.getStore()),
53    GDM(gdm),
54    refCount(0) {
55  stateMgr->getStoreManager().incrementReferenceCount(store);
56}
57
58ProgramState::ProgramState(const ProgramState &RHS)
59    : llvm::FoldingSetNode(),
60      stateMgr(RHS.stateMgr),
61      Env(RHS.Env),
62      store(RHS.store),
63      GDM(RHS.GDM),
64      refCount(0) {
65  stateMgr->getStoreManager().incrementReferenceCount(store);
66}
67
68ProgramState::~ProgramState() {
69  if (store)
70    stateMgr->getStoreManager().decrementReferenceCount(store);
71}
72
73ProgramStateManager::~ProgramStateManager() {
74  for (GDMContextsTy::iterator I=GDMContexts.begin(), E=GDMContexts.end();
75       I!=E; ++I)
76    I->second.second(I->second.first);
77}
78
79ProgramStateRef
80ProgramStateManager::removeDeadBindings(ProgramStateRef state,
81                                   const StackFrameContext *LCtx,
82                                   SymbolReaper& SymReaper) {
83
84  // This code essentially performs a "mark-and-sweep" of the VariableBindings.
85  // The roots are any Block-level exprs and Decls that our liveness algorithm
86  // tells us are live.  We then see what Decls they may reference, and keep
87  // those around.  This code more than likely can be made faster, and the
88  // frequency of which this method is called should be experimented with
89  // for optimum performance.
90  ProgramState NewState = *state;
91
92  NewState.Env = EnvMgr.removeDeadBindings(NewState.Env, SymReaper, state);
93
94  // Clean up the store.
95  StoreRef newStore = StoreMgr->removeDeadBindings(NewState.getStore(), LCtx,
96                                                   SymReaper);
97  NewState.setStore(newStore);
98  SymReaper.setReapedStore(newStore);
99
100  return getPersistentState(NewState);
101}
102
103ProgramStateRef ProgramStateManager::MarshalState(ProgramStateRef state,
104                                            const StackFrameContext *InitLoc) {
105  // make up an empty state for now.
106  ProgramState State(this,
107                EnvMgr.getInitialEnvironment(),
108                StoreMgr->getInitialStore(InitLoc),
109                GDMFactory.getEmptyMap());
110
111  return getPersistentState(State);
112}
113
114ProgramStateRef ProgramState::bindCompoundLiteral(const CompoundLiteralExpr *CL,
115                                            const LocationContext *LC,
116                                            SVal V) const {
117  const StoreRef &newStore =
118    getStateManager().StoreMgr->BindCompoundLiteral(getStore(), CL, LC, V);
119  return makeWithStore(newStore);
120}
121
122ProgramStateRef ProgramState::bindDecl(const VarRegion* VR, SVal IVal) const {
123  const StoreRef &newStore =
124    getStateManager().StoreMgr->BindDecl(getStore(), VR, IVal);
125  return makeWithStore(newStore);
126}
127
128ProgramStateRef ProgramState::bindDeclWithNoInit(const VarRegion* VR) const {
129  const StoreRef &newStore =
130    getStateManager().StoreMgr->BindDeclWithNoInit(getStore(), VR);
131  return makeWithStore(newStore);
132}
133
134ProgramStateRef ProgramState::bindLoc(Loc LV, SVal V) const {
135  ProgramStateManager &Mgr = getStateManager();
136  ProgramStateRef newState = makeWithStore(Mgr.StoreMgr->Bind(getStore(),
137                                                             LV, V));
138  const MemRegion *MR = LV.getAsRegion();
139  if (MR && Mgr.getOwningEngine())
140    return Mgr.getOwningEngine()->processRegionChange(newState, MR);
141
142  return newState;
143}
144
145ProgramStateRef ProgramState::bindDefault(SVal loc, SVal V) const {
146  ProgramStateManager &Mgr = getStateManager();
147  const MemRegion *R = cast<loc::MemRegionVal>(loc).getRegion();
148  const StoreRef &newStore = Mgr.StoreMgr->BindDefault(getStore(), R, V);
149  ProgramStateRef new_state = makeWithStore(newStore);
150  return Mgr.getOwningEngine() ?
151           Mgr.getOwningEngine()->processRegionChange(new_state, R) :
152           new_state;
153}
154
155ProgramStateRef
156ProgramState::invalidateRegions(ArrayRef<const MemRegion *> Regions,
157                                const Expr *E, unsigned Count,
158                                StoreManager::InvalidatedSymbols *IS,
159                                const CallOrObjCMessage *Call) const {
160  if (!IS) {
161    StoreManager::InvalidatedSymbols invalidated;
162    return invalidateRegionsImpl(Regions, E, Count,
163                                 invalidated, Call);
164  }
165  return invalidateRegionsImpl(Regions, E, Count, *IS, Call);
166}
167
168ProgramStateRef
169ProgramState::invalidateRegionsImpl(ArrayRef<const MemRegion *> Regions,
170                                    const Expr *E, unsigned Count,
171                                    StoreManager::InvalidatedSymbols &IS,
172                                    const CallOrObjCMessage *Call) const {
173  ProgramStateManager &Mgr = getStateManager();
174  SubEngine* Eng = Mgr.getOwningEngine();
175
176  if (Eng && Eng->wantsRegionChangeUpdate(this)) {
177    StoreManager::InvalidatedRegions Invalidated;
178    const StoreRef &newStore
179      = Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, IS,
180                                        Call, &Invalidated);
181    ProgramStateRef newState = makeWithStore(newStore);
182    return Eng->processRegionChanges(newState, &IS, Regions, Invalidated, Call);
183  }
184
185  const StoreRef &newStore =
186    Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, IS,
187                                    Call, NULL);
188  return makeWithStore(newStore);
189}
190
191ProgramStateRef ProgramState::unbindLoc(Loc LV) const {
192  assert(!isa<loc::MemRegionVal>(LV) && "Use invalidateRegion instead.");
193
194  Store OldStore = getStore();
195  const StoreRef &newStore = getStateManager().StoreMgr->Remove(OldStore, LV);
196
197  if (newStore.getStore() == OldStore)
198    return this;
199
200  return makeWithStore(newStore);
201}
202
203ProgramStateRef
204ProgramState::enterStackFrame(const LocationContext *callerCtx,
205                              const StackFrameContext *calleeCtx) const {
206  const StoreRef &new_store =
207    getStateManager().StoreMgr->enterStackFrame(this, callerCtx, calleeCtx);
208  return makeWithStore(new_store);
209}
210
211SVal ProgramState::getSValAsScalarOrLoc(const MemRegion *R) const {
212  // We only want to do fetches from regions that we can actually bind
213  // values.  For example, SymbolicRegions of type 'id<...>' cannot
214  // have direct bindings (but their can be bindings on their subregions).
215  if (!R->isBoundable())
216    return UnknownVal();
217
218  if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) {
219    QualType T = TR->getValueType();
220    if (Loc::isLocType(T) || T->isIntegerType())
221      return getSVal(R);
222  }
223
224  return UnknownVal();
225}
226
227SVal ProgramState::getSVal(Loc location, QualType T) const {
228  SVal V = getRawSVal(cast<Loc>(location), T);
229
230  // If 'V' is a symbolic value that is *perfectly* constrained to
231  // be a constant value, use that value instead to lessen the burden
232  // on later analysis stages (so we have less symbolic values to reason
233  // about).
234  if (!T.isNull()) {
235    if (SymbolRef sym = V.getAsSymbol()) {
236      if (const llvm::APSInt *Int = getSymVal(sym)) {
237        // FIXME: Because we don't correctly model (yet) sign-extension
238        // and truncation of symbolic values, we need to convert
239        // the integer value to the correct signedness and bitwidth.
240        //
241        // This shows up in the following:
242        //
243        //   char foo();
244        //   unsigned x = foo();
245        //   if (x == 54)
246        //     ...
247        //
248        //  The symbolic value stored to 'x' is actually the conjured
249        //  symbol for the call to foo(); the type of that symbol is 'char',
250        //  not unsigned.
251        const llvm::APSInt &NewV = getBasicVals().Convert(T, *Int);
252
253        if (isa<Loc>(V))
254          return loc::ConcreteInt(NewV);
255        else
256          return nonloc::ConcreteInt(NewV);
257      }
258    }
259  }
260
261  return V;
262}
263
264ProgramStateRef ProgramState::BindExpr(const Stmt *S,
265                                           const LocationContext *LCtx,
266                                           SVal V, bool Invalidate) const{
267  Environment NewEnv =
268    getStateManager().EnvMgr.bindExpr(Env, EnvironmentEntry(S, LCtx), V,
269                                      Invalidate);
270  if (NewEnv == Env)
271    return this;
272
273  ProgramState NewSt = *this;
274  NewSt.Env = NewEnv;
275  return getStateManager().getPersistentState(NewSt);
276}
277
278ProgramStateRef
279ProgramState::bindExprAndLocation(const Stmt *S, const LocationContext *LCtx,
280                                  SVal location,
281                                  SVal V) const {
282  Environment NewEnv =
283    getStateManager().EnvMgr.bindExprAndLocation(Env,
284                                                 EnvironmentEntry(S, LCtx),
285                                                 location, V);
286
287  if (NewEnv == Env)
288    return this;
289
290  ProgramState NewSt = *this;
291  NewSt.Env = NewEnv;
292  return getStateManager().getPersistentState(NewSt);
293}
294
295ProgramStateRef ProgramState::assumeInBound(DefinedOrUnknownSVal Idx,
296                                      DefinedOrUnknownSVal UpperBound,
297                                      bool Assumption,
298                                      QualType indexTy) const {
299  if (Idx.isUnknown() || UpperBound.isUnknown())
300    return this;
301
302  // Build an expression for 0 <= Idx < UpperBound.
303  // This is the same as Idx + MIN < UpperBound + MIN, if overflow is allowed.
304  // FIXME: This should probably be part of SValBuilder.
305  ProgramStateManager &SM = getStateManager();
306  SValBuilder &svalBuilder = SM.getSValBuilder();
307  ASTContext &Ctx = svalBuilder.getContext();
308
309  // Get the offset: the minimum value of the array index type.
310  BasicValueFactory &BVF = svalBuilder.getBasicValueFactory();
311  // FIXME: This should be using ValueManager::ArrayindexTy...somehow.
312  if (indexTy.isNull())
313    indexTy = Ctx.IntTy;
314  nonloc::ConcreteInt Min(BVF.getMinValue(indexTy));
315
316  // Adjust the index.
317  SVal newIdx = svalBuilder.evalBinOpNN(this, BO_Add,
318                                        cast<NonLoc>(Idx), Min, indexTy);
319  if (newIdx.isUnknownOrUndef())
320    return this;
321
322  // Adjust the upper bound.
323  SVal newBound =
324    svalBuilder.evalBinOpNN(this, BO_Add, cast<NonLoc>(UpperBound),
325                            Min, indexTy);
326
327  if (newBound.isUnknownOrUndef())
328    return this;
329
330  // Build the actual comparison.
331  SVal inBound = svalBuilder.evalBinOpNN(this, BO_LT,
332                                cast<NonLoc>(newIdx), cast<NonLoc>(newBound),
333                                Ctx.IntTy);
334  if (inBound.isUnknownOrUndef())
335    return this;
336
337  // Finally, let the constraint manager take care of it.
338  ConstraintManager &CM = SM.getConstraintManager();
339  return CM.assume(this, cast<DefinedSVal>(inBound), Assumption);
340}
341
342ProgramStateRef ProgramStateManager::getInitialState(const LocationContext *InitLoc) {
343  ProgramState State(this,
344                EnvMgr.getInitialEnvironment(),
345                StoreMgr->getInitialStore(InitLoc),
346                GDMFactory.getEmptyMap());
347
348  return getPersistentState(State);
349}
350
351ProgramStateRef ProgramStateManager::getPersistentStateWithGDM(
352                                                     ProgramStateRef FromState,
353                                                     ProgramStateRef GDMState) {
354  ProgramState NewState(*FromState);
355  NewState.GDM = GDMState->GDM;
356  return getPersistentState(NewState);
357}
358
359ProgramStateRef ProgramStateManager::getPersistentState(ProgramState &State) {
360
361  llvm::FoldingSetNodeID ID;
362  State.Profile(ID);
363  void *InsertPos;
364
365  if (ProgramState *I = StateSet.FindNodeOrInsertPos(ID, InsertPos))
366    return I;
367
368  ProgramState *newState = 0;
369  if (!freeStates.empty()) {
370    newState = freeStates.back();
371    freeStates.pop_back();
372  }
373  else {
374    newState = (ProgramState*) Alloc.Allocate<ProgramState>();
375  }
376  new (newState) ProgramState(State);
377  StateSet.InsertNode(newState, InsertPos);
378  return newState;
379}
380
381ProgramStateRef ProgramState::makeWithStore(const StoreRef &store) const {
382  ProgramState NewSt(*this);
383  NewSt.setStore(store);
384  return getStateManager().getPersistentState(NewSt);
385}
386
387void ProgramState::setStore(const StoreRef &newStore) {
388  Store newStoreStore = newStore.getStore();
389  if (newStoreStore)
390    stateMgr->getStoreManager().incrementReferenceCount(newStoreStore);
391  if (store)
392    stateMgr->getStoreManager().decrementReferenceCount(store);
393  store = newStoreStore;
394}
395
396//===----------------------------------------------------------------------===//
397//  State pretty-printing.
398//===----------------------------------------------------------------------===//
399
400void ProgramState::print(raw_ostream &Out,
401                         const char *NL, const char *Sep) const {
402  // Print the store.
403  ProgramStateManager &Mgr = getStateManager();
404  Mgr.getStoreManager().print(getStore(), Out, NL, Sep);
405
406  // Print out the environment.
407  Env.print(Out, NL, Sep);
408
409  // Print out the constraints.
410  Mgr.getConstraintManager().print(this, Out, NL, Sep);
411
412  // Print checker-specific data.
413  Mgr.getOwningEngine()->printState(Out, this, NL, Sep);
414}
415
416void ProgramState::printDOT(raw_ostream &Out) const {
417  print(Out, "\\l", "\\|");
418}
419
420void ProgramState::dump() const {
421  print(llvm::errs());
422}
423
424void ProgramState::printTaint(raw_ostream &Out,
425                              const char *NL, const char *Sep) const {
426  TaintMapImpl TM = get<TaintMap>();
427
428  if (!TM.isEmpty())
429    Out <<"Tainted Symbols:" << NL;
430
431  for (TaintMapImpl::iterator I = TM.begin(), E = TM.end(); I != E; ++I) {
432    Out << I->first << " : " << I->second << NL;
433  }
434}
435
436void ProgramState::dumpTaint() const {
437  printTaint(llvm::errs());
438}
439
440//===----------------------------------------------------------------------===//
441// Generic Data Map.
442//===----------------------------------------------------------------------===//
443
444void *const* ProgramState::FindGDM(void *K) const {
445  return GDM.lookup(K);
446}
447
448void*
449ProgramStateManager::FindGDMContext(void *K,
450                               void *(*CreateContext)(llvm::BumpPtrAllocator&),
451                               void (*DeleteContext)(void*)) {
452
453  std::pair<void*, void (*)(void*)>& p = GDMContexts[K];
454  if (!p.first) {
455    p.first = CreateContext(Alloc);
456    p.second = DeleteContext;
457  }
458
459  return p.first;
460}
461
462ProgramStateRef ProgramStateManager::addGDM(ProgramStateRef St, void *Key, void *Data){
463  ProgramState::GenericDataMap M1 = St->getGDM();
464  ProgramState::GenericDataMap M2 = GDMFactory.add(M1, Key, Data);
465
466  if (M1 == M2)
467    return St;
468
469  ProgramState NewSt = *St;
470  NewSt.GDM = M2;
471  return getPersistentState(NewSt);
472}
473
474ProgramStateRef ProgramStateManager::removeGDM(ProgramStateRef state, void *Key) {
475  ProgramState::GenericDataMap OldM = state->getGDM();
476  ProgramState::GenericDataMap NewM = GDMFactory.remove(OldM, Key);
477
478  if (NewM == OldM)
479    return state;
480
481  ProgramState NewState = *state;
482  NewState.GDM = NewM;
483  return getPersistentState(NewState);
484}
485
486void ScanReachableSymbols::anchor() { }
487
488bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
489  for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I)
490    if (!scan(*I))
491      return false;
492
493  return true;
494}
495
496bool ScanReachableSymbols::scan(const SymExpr *sym) {
497  unsigned &isVisited = visited[sym];
498  if (isVisited)
499    return true;
500  isVisited = 1;
501
502  if (!visitor.VisitSymbol(sym))
503    return false;
504
505  // TODO: should be rewritten using SymExpr::symbol_iterator.
506  switch (sym->getKind()) {
507    case SymExpr::RegionValueKind:
508    case SymExpr::ConjuredKind:
509    case SymExpr::DerivedKind:
510    case SymExpr::ExtentKind:
511    case SymExpr::MetadataKind:
512      break;
513    case SymExpr::CastSymbolKind:
514      return scan(cast<SymbolCast>(sym)->getOperand());
515    case SymExpr::SymIntKind:
516      return scan(cast<SymIntExpr>(sym)->getLHS());
517    case SymExpr::IntSymKind:
518      return scan(cast<IntSymExpr>(sym)->getRHS());
519    case SymExpr::SymSymKind: {
520      const SymSymExpr *x = cast<SymSymExpr>(sym);
521      return scan(x->getLHS()) && scan(x->getRHS());
522    }
523  }
524  return true;
525}
526
527bool ScanReachableSymbols::scan(SVal val) {
528  if (loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(&val))
529    return scan(X->getRegion());
530
531  if (nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(&val))
532    return scan(X->getLoc());
533
534  if (SymbolRef Sym = val.getAsSymbol())
535    return scan(Sym);
536
537  if (const SymExpr *Sym = val.getAsSymbolicExpression())
538    return scan(Sym);
539
540  if (nonloc::CompoundVal *X = dyn_cast<nonloc::CompoundVal>(&val))
541    return scan(*X);
542
543  return true;
544}
545
546bool ScanReachableSymbols::scan(const MemRegion *R) {
547  if (isa<MemSpaceRegion>(R))
548    return true;
549
550  unsigned &isVisited = visited[R];
551  if (isVisited)
552    return true;
553  isVisited = 1;
554
555  // If this is a symbolic region, visit the symbol for the region.
556  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
557    if (!visitor.VisitSymbol(SR->getSymbol()))
558      return false;
559
560  // If this is a subregion, also visit the parent regions.
561  if (const SubRegion *SR = dyn_cast<SubRegion>(R))
562    if (!scan(SR->getSuperRegion()))
563      return false;
564
565  // Now look at the binding to this region (if any).
566  if (!scan(state->getSValAsScalarOrLoc(R)))
567    return false;
568
569  // Now look at the subregions.
570  if (!SRM.get())
571    SRM.reset(state->getStateManager().getStoreManager().
572                                           getSubRegionMap(state->getStore()));
573
574  return SRM->iterSubRegions(R, *this);
575}
576
577bool ProgramState::scanReachableSymbols(SVal val, SymbolVisitor& visitor) const {
578  ScanReachableSymbols S(this, visitor);
579  return S.scan(val);
580}
581
582bool ProgramState::scanReachableSymbols(const SVal *I, const SVal *E,
583                                   SymbolVisitor &visitor) const {
584  ScanReachableSymbols S(this, visitor);
585  for ( ; I != E; ++I) {
586    if (!S.scan(*I))
587      return false;
588  }
589  return true;
590}
591
592bool ProgramState::scanReachableSymbols(const MemRegion * const *I,
593                                   const MemRegion * const *E,
594                                   SymbolVisitor &visitor) const {
595  ScanReachableSymbols S(this, visitor);
596  for ( ; I != E; ++I) {
597    if (!S.scan(*I))
598      return false;
599  }
600  return true;
601}
602
603ProgramStateRef ProgramState::addTaint(const Stmt *S,
604                                           const LocationContext *LCtx,
605                                           TaintTagType Kind) const {
606  if (const Expr *E = dyn_cast_or_null<Expr>(S))
607    S = E->IgnoreParens();
608
609  SymbolRef Sym = getSVal(S, LCtx).getAsSymbol();
610  if (Sym)
611    return addTaint(Sym, Kind);
612
613  const MemRegion *R = getSVal(S, LCtx).getAsRegion();
614  addTaint(R, Kind);
615
616  // Cannot add taint, so just return the state.
617  return this;
618}
619
620ProgramStateRef ProgramState::addTaint(const MemRegion *R,
621                                           TaintTagType Kind) const {
622  if (const SymbolicRegion *SR = dyn_cast_or_null<SymbolicRegion>(R))
623    return addTaint(SR->getSymbol(), Kind);
624  return this;
625}
626
627ProgramStateRef ProgramState::addTaint(SymbolRef Sym,
628                                           TaintTagType Kind) const {
629  // If this is a symbol cast, remove the cast before adding the taint. Taint
630  // is cast agnostic.
631  while (const SymbolCast *SC = dyn_cast<SymbolCast>(Sym))
632    Sym = SC->getOperand();
633
634  ProgramStateRef NewState = set<TaintMap>(Sym, Kind);
635  assert(NewState);
636  return NewState;
637}
638
639bool ProgramState::isTainted(const Stmt *S, const LocationContext *LCtx,
640                             TaintTagType Kind) const {
641  if (const Expr *E = dyn_cast_or_null<Expr>(S))
642    S = E->IgnoreParens();
643
644  SVal val = getSVal(S, LCtx);
645  return isTainted(val, Kind);
646}
647
648bool ProgramState::isTainted(SVal V, TaintTagType Kind) const {
649  if (const SymExpr *Sym = V.getAsSymExpr())
650    return isTainted(Sym, Kind);
651  if (const MemRegion *Reg = V.getAsRegion())
652    return isTainted(Reg, Kind);
653  return false;
654}
655
656bool ProgramState::isTainted(const MemRegion *Reg, TaintTagType K) const {
657  if (!Reg)
658    return false;
659
660  // Element region (array element) is tainted if either the base or the offset
661  // are tainted.
662  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Reg))
663    return isTainted(ER->getSuperRegion(), K) || isTainted(ER->getIndex(), K);
664
665  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Reg))
666    return isTainted(SR->getSymbol(), K);
667
668  if (const SubRegion *ER = dyn_cast<SubRegion>(Reg))
669    return isTainted(ER->getSuperRegion(), K);
670
671  return false;
672}
673
674bool ProgramState::isTainted(SymbolRef Sym, TaintTagType Kind) const {
675  if (!Sym)
676    return false;
677
678  // Traverse all the symbols this symbol depends on to see if any are tainted.
679  bool Tainted = false;
680  for (SymExpr::symbol_iterator SI = Sym->symbol_begin(), SE =Sym->symbol_end();
681       SI != SE; ++SI) {
682    assert(isa<SymbolData>(*SI));
683    const TaintTagType *Tag = get<TaintMap>(*SI);
684    Tainted = (Tag && *Tag == Kind);
685
686    // If this is a SymbolDerived with a tainted parent, it's also tainted.
687    if (const SymbolDerived *SD = dyn_cast<SymbolDerived>(*SI))
688      Tainted = Tainted || isTainted(SD->getParentSymbol(), Kind);
689
690    // If memory region is tainted, data is also tainted.
691    if (const SymbolRegionValue *SRV = dyn_cast<SymbolRegionValue>(*SI))
692      Tainted = Tainted || isTainted(SRV->getRegion(), Kind);
693
694    // If If this is a SymbolCast from a tainted value, it's also tainted.
695    if (const SymbolCast *SC = dyn_cast<SymbolCast>(*SI))
696      Tainted = Tainted || isTainted(SC->getOperand(), Kind);
697
698    if (Tainted)
699      return true;
700  }
701
702  return Tainted;
703}
704