ProgramState.cpp revision 56a46b51df691f857f7120aaf2d4deeff0b014de 
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/CallEvent.h"
16#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
17#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
18#include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/TaintManager.h"
20#include "llvm/Support/raw_ostream.h"
21
22using namespace clang;
23using namespace ento;
24
25// Give the vtable for ConstraintManager somewhere to live.
26// FIXME: Move this elsewhere.
27ConstraintManager::~ConstraintManager() {}
28
29namespace clang { namespace  ento {
30/// Increments the number of times this state is referenced.
31
32void ProgramStateRetain(const ProgramState *state) {
33  ++const_cast<ProgramState*>(state)->refCount;
34}
35
36/// Decrement the number of times this state is referenced.
37void ProgramStateRelease(const ProgramState *state) {
38  assert(state->refCount > 0);
39  ProgramState *s = const_cast<ProgramState*>(state);
40  if (--s->refCount == 0) {
41    ProgramStateManager &Mgr = s->getStateManager();
42    Mgr.StateSet.RemoveNode(s);
43    s->~ProgramState();
44    Mgr.freeStates.push_back(s);
45  }
46}
47}}
48
49ProgramState::ProgramState(ProgramStateManager *mgr, const Environment& env,
50                 StoreRef st, GenericDataMap gdm)
51  : stateMgr(mgr),
52    Env(env),
53    store(st.getStore()),
54    GDM(gdm),
55    refCount(0) {
56  stateMgr->getStoreManager().incrementReferenceCount(store);
57}
58
59ProgramState::ProgramState(const ProgramState &RHS)
60    : llvm::FoldingSetNode(),
61      stateMgr(RHS.stateMgr),
62      Env(RHS.Env),
63      store(RHS.store),
64      GDM(RHS.GDM),
65      refCount(0) {
66  stateMgr->getStoreManager().incrementReferenceCount(store);
67}
68
69ProgramState::~ProgramState() {
70  if (store)
71    stateMgr->getStoreManager().decrementReferenceCount(store);
72}
73
74ProgramStateManager::ProgramStateManager(ASTContext &Ctx,
75                                         StoreManagerCreator CreateSMgr,
76                                         ConstraintManagerCreator CreateCMgr,
77                                         llvm::BumpPtrAllocator &alloc,
78                                         SubEngine &SubEng)
79  : Eng(&SubEng), EnvMgr(alloc), GDMFactory(alloc),
80    svalBuilder(createSimpleSValBuilder(alloc, Ctx, *this)),
81    CallEventMgr(new CallEventManager(alloc)), Alloc(alloc) {
82  StoreMgr.reset((*CreateSMgr)(*this));
83  ConstraintMgr.reset((*CreateCMgr)(*this, SubEng));
84}
85
86
87ProgramStateManager::~ProgramStateManager() {
88  for (GDMContextsTy::iterator I=GDMContexts.begin(), E=GDMContexts.end();
89       I!=E; ++I)
90    I->second.second(I->second.first);
91}
92
93ProgramStateRef
94ProgramStateManager::removeDeadBindings(ProgramStateRef state,
95                                   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
117ProgramStateRef ProgramStateManager::MarshalState(ProgramStateRef state,
118                                            const StackFrameContext *InitLoc) {
119  // make up an empty state for now.
120  ProgramState State(this,
121                EnvMgr.getInitialEnvironment(),
122                StoreMgr->getInitialStore(InitLoc),
123                GDMFactory.getEmptyMap());
124
125  return getPersistentState(State);
126}
127
128ProgramStateRef ProgramState::bindCompoundLiteral(const CompoundLiteralExpr *CL,
129                                            const LocationContext *LC,
130                                            SVal V) const {
131  const StoreRef &newStore =
132    getStateManager().StoreMgr->bindCompoundLiteral(getStore(), CL, LC, V);
133  return makeWithStore(newStore);
134}
135
136ProgramStateRef ProgramState::bindLoc(Loc LV, SVal V, bool notifyChanges) const {
137  ProgramStateManager &Mgr = getStateManager();
138  ProgramStateRef newState = makeWithStore(Mgr.StoreMgr->Bind(getStore(),
139                                                             LV, V));
140  const MemRegion *MR = LV.getAsRegion();
141  if (MR && Mgr.getOwningEngine() && notifyChanges)
142    return Mgr.getOwningEngine()->processRegionChange(newState, MR);
143
144  return newState;
145}
146
147ProgramStateRef ProgramState::bindDefault(SVal loc, SVal V) const {
148  ProgramStateManager &Mgr = getStateManager();
149  const MemRegion *R = cast<loc::MemRegionVal>(loc).getRegion();
150  const StoreRef &newStore = Mgr.StoreMgr->BindDefault(getStore(), R, V);
151  ProgramStateRef new_state = makeWithStore(newStore);
152  return Mgr.getOwningEngine() ?
153           Mgr.getOwningEngine()->processRegionChange(new_state, R) :
154           new_state;
155}
156
157ProgramStateRef
158ProgramState::invalidateRegions(ArrayRef<const MemRegion *> Regions,
159                                const Expr *E, unsigned Count,
160                                const LocationContext *LCtx,
161                                StoreManager::InvalidatedSymbols *IS,
162                                const CallEvent *Call) const {
163  if (!IS) {
164    StoreManager::InvalidatedSymbols invalidated;
165    return invalidateRegionsImpl(Regions, E, Count, LCtx,
166                                 invalidated, Call);
167  }
168  return invalidateRegionsImpl(Regions, E, Count, LCtx, *IS, Call);
169}
170
171ProgramStateRef
172ProgramState::invalidateRegionsImpl(ArrayRef<const MemRegion *> Regions,
173                                    const Expr *E, unsigned Count,
174                                    const LocationContext *LCtx,
175                                    StoreManager::InvalidatedSymbols &IS,
176                                    const CallEvent *Call) const {
177  ProgramStateManager &Mgr = getStateManager();
178  SubEngine* Eng = Mgr.getOwningEngine();
179
180  if (Eng && Eng->wantsRegionChangeUpdate(this)) {
181    StoreManager::InvalidatedRegions Invalidated;
182    const StoreRef &newStore
183      = Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, LCtx, IS,
184                                        Call, &Invalidated);
185    ProgramStateRef newState = makeWithStore(newStore);
186    return Eng->processRegionChanges(newState, &IS, Regions, Invalidated, Call);
187  }
188
189  const StoreRef &newStore =
190    Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, LCtx, IS,
191                                    Call, NULL);
192  return makeWithStore(newStore);
193}
194
195ProgramStateRef ProgramState::killBinding(Loc LV) const {
196  assert(!isa<loc::MemRegionVal>(LV) && "Use invalidateRegion instead.");
197
198  Store OldStore = getStore();
199  const StoreRef &newStore =
200    getStateManager().StoreMgr->killBinding(OldStore, LV);
201
202  if (newStore.getStore() == OldStore)
203    return this;
204
205  return makeWithStore(newStore);
206}
207
208ProgramStateRef
209ProgramState::enterStackFrame(const CallEvent &Call,
210                              const StackFrameContext *CalleeCtx) const {
211  const StoreRef &NewStore =
212    getStateManager().StoreMgr->enterStackFrame(getStore(), Call, CalleeCtx);
213  return makeWithStore(NewStore);
214}
215
216SVal ProgramState::getSValAsScalarOrLoc(const MemRegion *R) const {
217  // We only want to do fetches from regions that we can actually bind
218  // values.  For example, SymbolicRegions of type 'id<...>' cannot
219  // have direct bindings (but their can be bindings on their subregions).
220  if (!R->isBoundable())
221    return UnknownVal();
222
223  if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) {
224    QualType T = TR->getValueType();
225    if (Loc::isLocType(T) || T->isIntegerType())
226      return getSVal(R);
227  }
228
229  return UnknownVal();
230}
231
232SVal ProgramState::getSVal(Loc location, QualType T) const {
233  SVal V = getRawSVal(cast<Loc>(location), T);
234
235  // If 'V' is a symbolic value that is *perfectly* constrained to
236  // be a constant value, use that value instead to lessen the burden
237  // on later analysis stages (so we have less symbolic values to reason
238  // about).
239  if (!T.isNull()) {
240    if (SymbolRef sym = V.getAsSymbol()) {
241      if (const llvm::APSInt *Int = getSymVal(sym)) {
242        // FIXME: Because we don't correctly model (yet) sign-extension
243        // and truncation of symbolic values, we need to convert
244        // the integer value to the correct signedness and bitwidth.
245        //
246        // This shows up in the following:
247        //
248        //   char foo();
249        //   unsigned x = foo();
250        //   if (x == 54)
251        //     ...
252        //
253        //  The symbolic value stored to 'x' is actually the conjured
254        //  symbol for the call to foo(); the type of that symbol is 'char',
255        //  not unsigned.
256        const llvm::APSInt &NewV = getBasicVals().Convert(T, *Int);
257
258        if (isa<Loc>(V))
259          return loc::ConcreteInt(NewV);
260        else
261          return nonloc::ConcreteInt(NewV);
262      }
263    }
264  }
265
266  return V;
267}
268
269ProgramStateRef ProgramState::BindExpr(const Stmt *S,
270                                           const LocationContext *LCtx,
271                                           SVal V, bool Invalidate) const{
272  Environment NewEnv =
273    getStateManager().EnvMgr.bindExpr(Env, EnvironmentEntry(S, LCtx), V,
274                                      Invalidate);
275  if (NewEnv == Env)
276    return this;
277
278  ProgramState NewSt = *this;
279  NewSt.Env = NewEnv;
280  return getStateManager().getPersistentState(NewSt);
281}
282
283ProgramStateRef
284ProgramState::bindExprAndLocation(const Stmt *S, const LocationContext *LCtx,
285                                  SVal location,
286                                  SVal V) const {
287  Environment NewEnv =
288    getStateManager().EnvMgr.bindExprAndLocation(Env,
289                                                 EnvironmentEntry(S, LCtx),
290                                                 location, V);
291
292  if (NewEnv == Env)
293    return this;
294
295  ProgramState NewSt = *this;
296  NewSt.Env = NewEnv;
297  return getStateManager().getPersistentState(NewSt);
298}
299
300ProgramStateRef ProgramState::assumeInBound(DefinedOrUnknownSVal Idx,
301                                      DefinedOrUnknownSVal UpperBound,
302                                      bool Assumption,
303                                      QualType indexTy) const {
304  if (Idx.isUnknown() || UpperBound.isUnknown())
305    return this;
306
307  // Build an expression for 0 <= Idx < UpperBound.
308  // This is the same as Idx + MIN < UpperBound + MIN, if overflow is allowed.
309  // FIXME: This should probably be part of SValBuilder.
310  ProgramStateManager &SM = getStateManager();
311  SValBuilder &svalBuilder = SM.getSValBuilder();
312  ASTContext &Ctx = svalBuilder.getContext();
313
314  // Get the offset: the minimum value of the array index type.
315  BasicValueFactory &BVF = svalBuilder.getBasicValueFactory();
316  // FIXME: This should be using ValueManager::ArrayindexTy...somehow.
317  if (indexTy.isNull())
318    indexTy = Ctx.IntTy;
319  nonloc::ConcreteInt Min(BVF.getMinValue(indexTy));
320
321  // Adjust the index.
322  SVal newIdx = svalBuilder.evalBinOpNN(this, BO_Add,
323                                        cast<NonLoc>(Idx), Min, indexTy);
324  if (newIdx.isUnknownOrUndef())
325    return this;
326
327  // Adjust the upper bound.
328  SVal newBound =
329    svalBuilder.evalBinOpNN(this, BO_Add, cast<NonLoc>(UpperBound),
330                            Min, indexTy);
331
332  if (newBound.isUnknownOrUndef())
333    return this;
334
335  // Build the actual comparison.
336  SVal inBound = svalBuilder.evalBinOpNN(this, BO_LT,
337                                cast<NonLoc>(newIdx), cast<NonLoc>(newBound),
338                                Ctx.IntTy);
339  if (inBound.isUnknownOrUndef())
340    return this;
341
342  // Finally, let the constraint manager take care of it.
343  ConstraintManager &CM = SM.getConstraintManager();
344  return CM.assume(this, cast<DefinedSVal>(inBound), Assumption);
345}
346
347ProgramStateRef ProgramStateManager::getInitialState(const LocationContext *InitLoc) {
348  ProgramState State(this,
349                EnvMgr.getInitialEnvironment(),
350                StoreMgr->getInitialStore(InitLoc),
351                GDMFactory.getEmptyMap());
352
353  return getPersistentState(State);
354}
355
356ProgramStateRef ProgramStateManager::getPersistentStateWithGDM(
357                                                     ProgramStateRef FromState,
358                                                     ProgramStateRef GDMState) {
359  ProgramState NewState(*FromState);
360  NewState.GDM = GDMState->GDM;
361  return getPersistentState(NewState);
362}
363
364ProgramStateRef ProgramStateManager::getPersistentState(ProgramState &State) {
365
366  llvm::FoldingSetNodeID ID;
367  State.Profile(ID);
368  void *InsertPos;
369
370  if (ProgramState *I = StateSet.FindNodeOrInsertPos(ID, InsertPos))
371    return I;
372
373  ProgramState *newState = 0;
374  if (!freeStates.empty()) {
375    newState = freeStates.back();
376    freeStates.pop_back();
377  }
378  else {
379    newState = (ProgramState*) Alloc.Allocate<ProgramState>();
380  }
381  new (newState) ProgramState(State);
382  StateSet.InsertNode(newState, InsertPos);
383  return newState;
384}
385
386ProgramStateRef ProgramState::makeWithStore(const StoreRef &store) const {
387  ProgramState NewSt(*this);
388  NewSt.setStore(store);
389  return getStateManager().getPersistentState(NewSt);
390}
391
392void ProgramState::setStore(const StoreRef &newStore) {
393  Store newStoreStore = newStore.getStore();
394  if (newStoreStore)
395    stateMgr->getStoreManager().incrementReferenceCount(newStoreStore);
396  if (store)
397    stateMgr->getStoreManager().decrementReferenceCount(store);
398  store = newStoreStore;
399}
400
401//===----------------------------------------------------------------------===//
402//  State pretty-printing.
403//===----------------------------------------------------------------------===//
404
405void ProgramState::print(raw_ostream &Out,
406                         const char *NL, const char *Sep) const {
407  // Print the store.
408  ProgramStateManager &Mgr = getStateManager();
409  Mgr.getStoreManager().print(getStore(), Out, NL, Sep);
410
411  // Print out the environment.
412  Env.print(Out, NL, Sep);
413
414  // Print out the constraints.
415  Mgr.getConstraintManager().print(this, Out, NL, Sep);
416
417  // Print checker-specific data.
418  Mgr.getOwningEngine()->printState(Out, this, NL, Sep);
419}
420
421void ProgramState::printDOT(raw_ostream &Out) const {
422  print(Out, "\\l", "\\|");
423}
424
425void ProgramState::dump() const {
426  print(llvm::errs());
427}
428
429void ProgramState::printTaint(raw_ostream &Out,
430                              const char *NL, const char *Sep) const {
431  TaintMapImpl TM = get<TaintMap>();
432
433  if (!TM.isEmpty())
434    Out <<"Tainted Symbols:" << NL;
435
436  for (TaintMapImpl::iterator I = TM.begin(), E = TM.end(); I != E; ++I) {
437    Out << I->first << " : " << I->second << NL;
438  }
439}
440
441void ProgramState::dumpTaint() const {
442  printTaint(llvm::errs());
443}
444
445//===----------------------------------------------------------------------===//
446// Generic Data Map.
447//===----------------------------------------------------------------------===//
448
449void *const* ProgramState::FindGDM(void *K) const {
450  return GDM.lookup(K);
451}
452
453void*
454ProgramStateManager::FindGDMContext(void *K,
455                               void *(*CreateContext)(llvm::BumpPtrAllocator&),
456                               void (*DeleteContext)(void*)) {
457
458  std::pair<void*, void (*)(void*)>& p = GDMContexts[K];
459  if (!p.first) {
460    p.first = CreateContext(Alloc);
461    p.second = DeleteContext;
462  }
463
464  return p.first;
465}
466
467ProgramStateRef ProgramStateManager::addGDM(ProgramStateRef St, void *Key, void *Data){
468  ProgramState::GenericDataMap M1 = St->getGDM();
469  ProgramState::GenericDataMap M2 = GDMFactory.add(M1, Key, Data);
470
471  if (M1 == M2)
472    return St;
473
474  ProgramState NewSt = *St;
475  NewSt.GDM = M2;
476  return getPersistentState(NewSt);
477}
478
479ProgramStateRef ProgramStateManager::removeGDM(ProgramStateRef state, void *Key) {
480  ProgramState::GenericDataMap OldM = state->getGDM();
481  ProgramState::GenericDataMap NewM = GDMFactory.remove(OldM, Key);
482
483  if (NewM == OldM)
484    return state;
485
486  ProgramState NewState = *state;
487  NewState.GDM = NewM;
488  return getPersistentState(NewState);
489}
490
491bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
492  for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I)
493    if (!scan(*I))
494      return false;
495
496  return true;
497}
498
499bool ScanReachableSymbols::scan(const SymExpr *sym) {
500  unsigned &isVisited = visited[sym];
501  if (isVisited)
502    return true;
503  isVisited = 1;
504
505  if (!visitor.VisitSymbol(sym))
506    return false;
507
508  // TODO: should be rewritten using SymExpr::symbol_iterator.
509  switch (sym->getKind()) {
510    case SymExpr::RegionValueKind:
511    case SymExpr::ConjuredKind:
512    case SymExpr::DerivedKind:
513    case SymExpr::ExtentKind:
514    case SymExpr::MetadataKind:
515      break;
516    case SymExpr::CastSymbolKind:
517      return scan(cast<SymbolCast>(sym)->getOperand());
518    case SymExpr::SymIntKind:
519      return scan(cast<SymIntExpr>(sym)->getLHS());
520    case SymExpr::IntSymKind:
521      return scan(cast<IntSymExpr>(sym)->getRHS());
522    case SymExpr::SymSymKind: {
523      const SymSymExpr *x = cast<SymSymExpr>(sym);
524      return scan(x->getLHS()) && scan(x->getRHS());
525    }
526  }
527  return true;
528}
529
530bool ScanReachableSymbols::scan(SVal val) {
531  if (loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(&val))
532    return scan(X->getRegion());
533
534  if (nonloc::LazyCompoundVal *X = dyn_cast<nonloc::LazyCompoundVal>(&val))
535    return scan(X->getRegion());
536
537  if (nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(&val))
538    return scan(X->getLoc());
539
540  if (SymbolRef Sym = val.getAsSymbol())
541    return scan(Sym);
542
543  if (const SymExpr *Sym = val.getAsSymbolicExpression())
544    return scan(Sym);
545
546  if (nonloc::CompoundVal *X = dyn_cast<nonloc::CompoundVal>(&val))
547    return scan(*X);
548
549  return true;
550}
551
552bool ScanReachableSymbols::scan(const MemRegion *R) {
553  if (isa<MemSpaceRegion>(R))
554    return true;
555
556  unsigned &isVisited = visited[R];
557  if (isVisited)
558    return true;
559  isVisited = 1;
560
561
562  if (!visitor.VisitMemRegion(R))
563    return false;
564
565  // If this is a symbolic region, visit the symbol for the region.
566  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
567    if (!visitor.VisitSymbol(SR->getSymbol()))
568      return false;
569
570  // If this is a subregion, also visit the parent regions.
571  if (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
572    const MemRegion *Super = SR->getSuperRegion();
573    if (!scan(Super))
574      return false;
575
576    // When we reach the topmost region, scan all symbols in it.
577    if (isa<MemSpaceRegion>(Super)) {
578      StoreManager &StoreMgr = state->getStateManager().getStoreManager();
579      if (!StoreMgr.scanReachableSymbols(state->getStore(), SR, *this))
580        return false;
581    }
582  }
583
584  // Regions captured by a block are also implicitly reachable.
585  if (const BlockDataRegion *BDR = dyn_cast<BlockDataRegion>(R)) {
586    BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
587                                              E = BDR->referenced_vars_end();
588    for ( ; I != E; ++I) {
589      if (!scan(I.getCapturedRegion()))
590        return false;
591    }
592  }
593
594  return true;
595}
596
597bool ProgramState::scanReachableSymbols(SVal val, SymbolVisitor& visitor) const {
598  ScanReachableSymbols S(this, visitor);
599  return S.scan(val);
600}
601
602bool ProgramState::scanReachableSymbols(const SVal *I, const SVal *E,
603                                   SymbolVisitor &visitor) const {
604  ScanReachableSymbols S(this, visitor);
605  for ( ; I != E; ++I) {
606    if (!S.scan(*I))
607      return false;
608  }
609  return true;
610}
611
612bool ProgramState::scanReachableSymbols(const MemRegion * const *I,
613                                   const MemRegion * const *E,
614                                   SymbolVisitor &visitor) const {
615  ScanReachableSymbols S(this, visitor);
616  for ( ; I != E; ++I) {
617    if (!S.scan(*I))
618      return false;
619  }
620  return true;
621}
622
623ProgramStateRef ProgramState::addTaint(const Stmt *S,
624                                           const LocationContext *LCtx,
625                                           TaintTagType Kind) const {
626  if (const Expr *E = dyn_cast_or_null<Expr>(S))
627    S = E->IgnoreParens();
628
629  SymbolRef Sym = getSVal(S, LCtx).getAsSymbol();
630  if (Sym)
631    return addTaint(Sym, Kind);
632
633  const MemRegion *R = getSVal(S, LCtx).getAsRegion();
634  addTaint(R, Kind);
635
636  // Cannot add taint, so just return the state.
637  return this;
638}
639
640ProgramStateRef ProgramState::addTaint(const MemRegion *R,
641                                           TaintTagType Kind) const {
642  if (const SymbolicRegion *SR = dyn_cast_or_null<SymbolicRegion>(R))
643    return addTaint(SR->getSymbol(), Kind);
644  return this;
645}
646
647ProgramStateRef ProgramState::addTaint(SymbolRef Sym,
648                                           TaintTagType Kind) const {
649  // If this is a symbol cast, remove the cast before adding the taint. Taint
650  // is cast agnostic.
651  while (const SymbolCast *SC = dyn_cast<SymbolCast>(Sym))
652    Sym = SC->getOperand();
653
654  ProgramStateRef NewState = set<TaintMap>(Sym, Kind);
655  assert(NewState);
656  return NewState;
657}
658
659bool ProgramState::isTainted(const Stmt *S, const LocationContext *LCtx,
660                             TaintTagType Kind) const {
661  if (const Expr *E = dyn_cast_or_null<Expr>(S))
662    S = E->IgnoreParens();
663
664  SVal val = getSVal(S, LCtx);
665  return isTainted(val, Kind);
666}
667
668bool ProgramState::isTainted(SVal V, TaintTagType Kind) const {
669  if (const SymExpr *Sym = V.getAsSymExpr())
670    return isTainted(Sym, Kind);
671  if (const MemRegion *Reg = V.getAsRegion())
672    return isTainted(Reg, Kind);
673  return false;
674}
675
676bool ProgramState::isTainted(const MemRegion *Reg, TaintTagType K) const {
677  if (!Reg)
678    return false;
679
680  // Element region (array element) is tainted if either the base or the offset
681  // are tainted.
682  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Reg))
683    return isTainted(ER->getSuperRegion(), K) || isTainted(ER->getIndex(), K);
684
685  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Reg))
686    return isTainted(SR->getSymbol(), K);
687
688  if (const SubRegion *ER = dyn_cast<SubRegion>(Reg))
689    return isTainted(ER->getSuperRegion(), K);
690
691  return false;
692}
693
694bool ProgramState::isTainted(SymbolRef Sym, TaintTagType Kind) const {
695  if (!Sym)
696    return false;
697
698  // Traverse all the symbols this symbol depends on to see if any are tainted.
699  bool Tainted = false;
700  for (SymExpr::symbol_iterator SI = Sym->symbol_begin(), SE =Sym->symbol_end();
701       SI != SE; ++SI) {
702    assert(isa<SymbolData>(*SI));
703    const TaintTagType *Tag = get<TaintMap>(*SI);
704    Tainted = (Tag && *Tag == Kind);
705
706    // If this is a SymbolDerived with a tainted parent, it's also tainted.
707    if (const SymbolDerived *SD = dyn_cast<SymbolDerived>(*SI))
708      Tainted = Tainted || isTainted(SD->getParentSymbol(), Kind);
709
710    // If memory region is tainted, data is also tainted.
711    if (const SymbolRegionValue *SRV = dyn_cast<SymbolRegionValue>(*SI))
712      Tainted = Tainted || isTainted(SRV->getRegion(), Kind);
713
714    // If If this is a SymbolCast from a tainted value, it's also tainted.
715    if (const SymbolCast *SC = dyn_cast<SymbolCast>(*SI))
716      Tainted = Tainted || isTainted(SC->getOperand(), Kind);
717
718    if (Tainted)
719      return true;
720  }
721
722  return Tainted;
723}
724
725/// The GDM component containing the dynamic type info. This is a map from a
726/// symbol to it's most likely type.
727namespace clang {
728namespace ento {
729typedef llvm::ImmutableMap<const MemRegion *, DynamicTypeInfo> DynamicTypeMap;
730template<> struct ProgramStateTrait<DynamicTypeMap>
731    : public ProgramStatePartialTrait<DynamicTypeMap> {
732  static void *GDMIndex() { static int index; return &index; }
733};
734}}
735
736DynamicTypeInfo ProgramState::getDynamicTypeInfo(const MemRegion *Reg) const {
737  Reg = Reg->StripCasts();
738
739  // Look up the dynamic type in the GDM.
740  const DynamicTypeInfo *GDMType = get<DynamicTypeMap>(Reg);
741  if (GDMType)
742    return *GDMType;
743
744  // Otherwise, fall back to what we know about the region.
745  if (const TypedRegion *TR = dyn_cast<TypedRegion>(Reg))
746    return DynamicTypeInfo(TR->getLocationType(), /*CanBeSubclass=*/false);
747
748  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Reg)) {
749    SymbolRef Sym = SR->getSymbol();
750    return DynamicTypeInfo(Sym->getType(getStateManager().getContext()));
751  }
752
753  return DynamicTypeInfo();
754}
755
756ProgramStateRef ProgramState::setDynamicTypeInfo(const MemRegion *Reg,
757                                                 DynamicTypeInfo NewTy) const {
758  Reg = Reg->StripCasts();
759  ProgramStateRef NewState = set<DynamicTypeMap>(Reg, NewTy);
760  assert(NewState);
761  return NewState;
762}
763