Add the clang library to the repo (with some of my changes, too).

1 files changed, 709 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ProgramState.cpp b/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
new file mode 100644
index 0000000..b9cfa27
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
@@ -0,0 +1,709 @@
+//= ProgramState.cpp - Path-Sensitive "State" for tracking values --*- C++ -*--=
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements ProgramState and ProgramStateManager.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/CFG.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/TaintManager.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+
+// Give the vtable for ConstraintManager somewhere to live.
+// FIXME: Move this elsewhere.
+ConstraintManager::~ConstraintManager() {}
+
+namespace clang { namespace  ento {
+/// Increments the number of times this state is referenced.
+
+void ProgramStateRetain(const ProgramState *state) {
+  ++const_cast<ProgramState*>(state)->refCount;
+}
+
+/// Decrement the number of times this state is referenced.
+void ProgramStateRelease(const ProgramState *state) {
+  assert(state->refCount > 0);
+  ProgramState *s = const_cast<ProgramState*>(state);
+  if (--s->refCount == 0) {
+    ProgramStateManager &Mgr = s->getStateManager();
+    Mgr.StateSet.RemoveNode(s);
+    s->~ProgramState();    
+    Mgr.freeStates.push_back(s);
+  }
+}
+}}
+
+ProgramState::ProgramState(ProgramStateManager *mgr, const Environment& env,
+                 StoreRef st, GenericDataMap gdm)
+  : stateMgr(mgr),
+    Env(env),
+    store(st.getStore()),
+    GDM(gdm),
+    refCount(0) {
+  stateMgr->getStoreManager().incrementReferenceCount(store);
+}
+
+ProgramState::ProgramState(const ProgramState &RHS)
+    : llvm::FoldingSetNode(),
+      stateMgr(RHS.stateMgr),
+      Env(RHS.Env),
+      store(RHS.store),
+      GDM(RHS.GDM),
+      refCount(0) {
+  stateMgr->getStoreManager().incrementReferenceCount(store);
+}
+
+ProgramState::~ProgramState() {
+  if (store)
+    stateMgr->getStoreManager().decrementReferenceCount(store);
+}
+
+ProgramStateManager::~ProgramStateManager() {
+  for (GDMContextsTy::iterator I=GDMContexts.begin(), E=GDMContexts.end();
+       I!=E; ++I)
+    I->second.second(I->second.first);
+}
+
+ProgramStateRef 
+ProgramStateManager::removeDeadBindings(ProgramStateRef state,
+                                   const StackFrameContext *LCtx,
+                                   SymbolReaper& SymReaper) {
+
+  // This code essentially performs a "mark-and-sweep" of the VariableBindings.
+  // The roots are any Block-level exprs and Decls that our liveness algorithm
+  // tells us are live.  We then see what Decls they may reference, and keep
+  // those around.  This code more than likely can be made faster, and the
+  // frequency of which this method is called should be experimented with
+  // for optimum performance.
+  ProgramState NewState = *state;
+
+  NewState.Env = EnvMgr.removeDeadBindings(NewState.Env, SymReaper, state);
+
+  // Clean up the store.
+  StoreRef newStore = StoreMgr->removeDeadBindings(NewState.getStore(), LCtx,
+                                                   SymReaper);
+  NewState.setStore(newStore);
+  SymReaper.setReapedStore(newStore);
+  
+  return getPersistentState(NewState);
+}
+
+ProgramStateRef ProgramStateManager::MarshalState(ProgramStateRef state,
+                                            const StackFrameContext *InitLoc) {
+  // make up an empty state for now.
+  ProgramState State(this,
+                EnvMgr.getInitialEnvironment(),
+                StoreMgr->getInitialStore(InitLoc),
+                GDMFactory.getEmptyMap());
+
+  return getPersistentState(State);
+}
+
+ProgramStateRef ProgramState::bindCompoundLiteral(const CompoundLiteralExpr *CL,
+                                            const LocationContext *LC,
+                                            SVal V) const {
+  const StoreRef &newStore = 
+    getStateManager().StoreMgr->BindCompoundLiteral(getStore(), CL, LC, V);
+  return makeWithStore(newStore);
+}
+
+ProgramStateRef ProgramState::bindDecl(const VarRegion* VR, SVal IVal) const {
+  const StoreRef &newStore =
+    getStateManager().StoreMgr->BindDecl(getStore(), VR, IVal);
+  return makeWithStore(newStore);
+}
+
+ProgramStateRef ProgramState::bindDeclWithNoInit(const VarRegion* VR) const {
+  const StoreRef &newStore =
+    getStateManager().StoreMgr->BindDeclWithNoInit(getStore(), VR);
+  return makeWithStore(newStore);
+}
+
+ProgramStateRef ProgramState::bindLoc(Loc LV, SVal V) const {
+  ProgramStateManager &Mgr = getStateManager();
+  ProgramStateRef newState = makeWithStore(Mgr.StoreMgr->Bind(getStore(), 
+                                                             LV, V));
+  const MemRegion *MR = LV.getAsRegion();
+  if (MR && Mgr.getOwningEngine())
+    return Mgr.getOwningEngine()->processRegionChange(newState, MR);
+
+  return newState;
+}
+
+ProgramStateRef ProgramState::bindDefault(SVal loc, SVal V) const {
+  ProgramStateManager &Mgr = getStateManager();
+  const MemRegion *R = cast<loc::MemRegionVal>(loc).getRegion();
+  const StoreRef &newStore = Mgr.StoreMgr->BindDefault(getStore(), R, V);
+  ProgramStateRef new_state = makeWithStore(newStore);
+  return Mgr.getOwningEngine() ? 
+           Mgr.getOwningEngine()->processRegionChange(new_state, R) : 
+           new_state;
+}
+
+ProgramStateRef 
+ProgramState::invalidateRegions(ArrayRef<const MemRegion *> Regions,
+                                const Expr *E, unsigned Count,
+                                const LocationContext *LCtx,
+                                StoreManager::InvalidatedSymbols *IS,
+                                const CallOrObjCMessage *Call) const {
+  if (!IS) {
+    StoreManager::InvalidatedSymbols invalidated;
+    return invalidateRegionsImpl(Regions, E, Count, LCtx,
+                                 invalidated, Call);
+  }
+  return invalidateRegionsImpl(Regions, E, Count, LCtx, *IS, Call);
+}
+
+ProgramStateRef 
+ProgramState::invalidateRegionsImpl(ArrayRef<const MemRegion *> Regions,
+                                    const Expr *E, unsigned Count,
+                                    const LocationContext *LCtx,
+                                    StoreManager::InvalidatedSymbols &IS,
+                                    const CallOrObjCMessage *Call) const {
+  ProgramStateManager &Mgr = getStateManager();
+  SubEngine* Eng = Mgr.getOwningEngine();
+ 
+  if (Eng && Eng->wantsRegionChangeUpdate(this)) {
+    StoreManager::InvalidatedRegions Invalidated;
+    const StoreRef &newStore
+      = Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, LCtx, IS,
+                                        Call, &Invalidated);
+    ProgramStateRef newState = makeWithStore(newStore);
+    return Eng->processRegionChanges(newState, &IS, Regions, Invalidated, Call);
+  }
+
+  const StoreRef &newStore =
+    Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, LCtx, IS,
+                                    Call, NULL);
+  return makeWithStore(newStore);
+}
+
+ProgramStateRef ProgramState::unbindLoc(Loc LV) const {
+  assert(!isa<loc::MemRegionVal>(LV) && "Use invalidateRegion instead.");
+
+  Store OldStore = getStore();
+  const StoreRef &newStore = getStateManager().StoreMgr->Remove(OldStore, LV);
+
+  if (newStore.getStore() == OldStore)
+    return this;
+
+  return makeWithStore(newStore);
+}
+
+ProgramStateRef 
+ProgramState::enterStackFrame(const LocationContext *callerCtx,
+                              const StackFrameContext *calleeCtx) const {
+  const StoreRef &new_store =
+    getStateManager().StoreMgr->enterStackFrame(this, callerCtx, calleeCtx);
+  return makeWithStore(new_store);
+}
+
+SVal ProgramState::getSValAsScalarOrLoc(const MemRegion *R) const {
+  // We only want to do fetches from regions that we can actually bind
+  // values.  For example, SymbolicRegions of type 'id<...>' cannot
+  // have direct bindings (but their can be bindings on their subregions).
+  if (!R->isBoundable())
+    return UnknownVal();
+
+  if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) {
+    QualType T = TR->getValueType();
+    if (Loc::isLocType(T) || T->isIntegerType())
+      return getSVal(R);
+  }
+
+  return UnknownVal();
+}
+
+SVal ProgramState::getSVal(Loc location, QualType T) const {
+  SVal V = getRawSVal(cast<Loc>(location), T);
+
+  // If 'V' is a symbolic value that is *perfectly* constrained to
+  // be a constant value, use that value instead to lessen the burden
+  // on later analysis stages (so we have less symbolic values to reason
+  // about).
+  if (!T.isNull()) {
+    if (SymbolRef sym = V.getAsSymbol()) {
+      if (const llvm::APSInt *Int = getSymVal(sym)) {
+        // FIXME: Because we don't correctly model (yet) sign-extension
+        // and truncation of symbolic values, we need to convert
+        // the integer value to the correct signedness and bitwidth.
+        //
+        // This shows up in the following:
+        //
+        //   char foo();
+        //   unsigned x = foo();
+        //   if (x == 54)
+        //     ...
+        //
+        //  The symbolic value stored to 'x' is actually the conjured
+        //  symbol for the call to foo(); the type of that symbol is 'char',
+        //  not unsigned.
+        const llvm::APSInt &NewV = getBasicVals().Convert(T, *Int);
+        
+        if (isa<Loc>(V))
+          return loc::ConcreteInt(NewV);
+        else
+          return nonloc::ConcreteInt(NewV);
+      }
+    }
+  }
+  
+  return V;
+}
+
+ProgramStateRef ProgramState::BindExpr(const Stmt *S,
+                                           const LocationContext *LCtx,
+                                           SVal V, bool Invalidate) const{
+  Environment NewEnv =
+    getStateManager().EnvMgr.bindExpr(Env, EnvironmentEntry(S, LCtx), V,
+                                      Invalidate);
+  if (NewEnv == Env)
+    return this;
+
+  ProgramState NewSt = *this;
+  NewSt.Env = NewEnv;
+  return getStateManager().getPersistentState(NewSt);
+}
+
+ProgramStateRef 
+ProgramState::bindExprAndLocation(const Stmt *S, const LocationContext *LCtx,
+                                  SVal location,
+                                  SVal V) const {
+  Environment NewEnv =
+    getStateManager().EnvMgr.bindExprAndLocation(Env,
+                                                 EnvironmentEntry(S, LCtx),
+                                                 location, V);
+
+  if (NewEnv == Env)
+    return this;
+  
+  ProgramState NewSt = *this;
+  NewSt.Env = NewEnv;
+  return getStateManager().getPersistentState(NewSt);
+}
+
+ProgramStateRef ProgramState::assumeInBound(DefinedOrUnknownSVal Idx,
+                                      DefinedOrUnknownSVal UpperBound,
+                                      bool Assumption,
+                                      QualType indexTy) const {
+  if (Idx.isUnknown() || UpperBound.isUnknown())
+    return this;
+
+  // Build an expression for 0 <= Idx < UpperBound.
+  // This is the same as Idx + MIN < UpperBound + MIN, if overflow is allowed.
+  // FIXME: This should probably be part of SValBuilder.
+  ProgramStateManager &SM = getStateManager();
+  SValBuilder &svalBuilder = SM.getSValBuilder();
+  ASTContext &Ctx = svalBuilder.getContext();
+
+  // Get the offset: the minimum value of the array index type.
+  BasicValueFactory &BVF = svalBuilder.getBasicValueFactory();
+  // FIXME: This should be using ValueManager::ArrayindexTy...somehow.
+  if (indexTy.isNull())
+    indexTy = Ctx.IntTy;
+  nonloc::ConcreteInt Min(BVF.getMinValue(indexTy));
+
+  // Adjust the index.
+  SVal newIdx = svalBuilder.evalBinOpNN(this, BO_Add,
+                                        cast<NonLoc>(Idx), Min, indexTy);
+  if (newIdx.isUnknownOrUndef())
+    return this;
+
+  // Adjust the upper bound.
+  SVal newBound =
+    svalBuilder.evalBinOpNN(this, BO_Add, cast<NonLoc>(UpperBound),
+                            Min, indexTy);
+
+  if (newBound.isUnknownOrUndef())
+    return this;
+
+  // Build the actual comparison.
+  SVal inBound = svalBuilder.evalBinOpNN(this, BO_LT,
+                                cast<NonLoc>(newIdx), cast<NonLoc>(newBound),
+                                Ctx.IntTy);
+  if (inBound.isUnknownOrUndef())
+    return this;
+
+  // Finally, let the constraint manager take care of it.
+  ConstraintManager &CM = SM.getConstraintManager();
+  return CM.assume(this, cast<DefinedSVal>(inBound), Assumption);
+}
+
+ProgramStateRef ProgramStateManager::getInitialState(const LocationContext *InitLoc) {
+  ProgramState State(this,
+                EnvMgr.getInitialEnvironment(),
+                StoreMgr->getInitialStore(InitLoc),
+                GDMFactory.getEmptyMap());
+
+  return getPersistentState(State);
+}
+
+ProgramStateRef ProgramStateManager::getPersistentStateWithGDM(
+                                                     ProgramStateRef FromState,
+                                                     ProgramStateRef GDMState) {
+  ProgramState NewState(*FromState);
+  NewState.GDM = GDMState->GDM;
+  return getPersistentState(NewState);
+}
+
+ProgramStateRef ProgramStateManager::getPersistentState(ProgramState &State) {
+
+  llvm::FoldingSetNodeID ID;
+  State.Profile(ID);
+  void *InsertPos;
+
+  if (ProgramState *I = StateSet.FindNodeOrInsertPos(ID, InsertPos))
+    return I;
+
+  ProgramState *newState = 0;
+  if (!freeStates.empty()) {
+    newState = freeStates.back();
+    freeStates.pop_back();    
+  }
+  else {
+    newState = (ProgramState*) Alloc.Allocate<ProgramState>();
+  }
+  new (newState) ProgramState(State);
+  StateSet.InsertNode(newState, InsertPos);
+  return newState;
+}
+
+ProgramStateRef ProgramState::makeWithStore(const StoreRef &store) const {
+  ProgramState NewSt(*this);
+  NewSt.setStore(store);
+  return getStateManager().getPersistentState(NewSt);
+}
+
+void ProgramState::setStore(const StoreRef &newStore) {
+  Store newStoreStore = newStore.getStore();
+  if (newStoreStore)
+    stateMgr->getStoreManager().incrementReferenceCount(newStoreStore);
+  if (store)
+    stateMgr->getStoreManager().decrementReferenceCount(store);
+  store = newStoreStore;
+}
+
+//===----------------------------------------------------------------------===//
+//  State pretty-printing.
+//===----------------------------------------------------------------------===//
+
+void ProgramState::print(raw_ostream &Out,
+                         const char *NL, const char *Sep) const {
+  // Print the store.
+  ProgramStateManager &Mgr = getStateManager();
+  Mgr.getStoreManager().print(getStore(), Out, NL, Sep);
+
+  // Print out the environment.
+  Env.print(Out, NL, Sep);
+
+  // Print out the constraints.
+  Mgr.getConstraintManager().print(this, Out, NL, Sep);
+
+  // Print checker-specific data.
+  Mgr.getOwningEngine()->printState(Out, this, NL, Sep);
+}
+
+void ProgramState::printDOT(raw_ostream &Out) const {
+  print(Out, "\\l", "\\|");
+}
+
+void ProgramState::dump() const {
+  print(llvm::errs());
+}
+
+void ProgramState::printTaint(raw_ostream &Out,
+                              const char *NL, const char *Sep) const {
+  TaintMapImpl TM = get<TaintMap>();
+
+  if (!TM.isEmpty())
+    Out <<"Tainted Symbols:" << NL;
+
+  for (TaintMapImpl::iterator I = TM.begin(), E = TM.end(); I != E; ++I) {
+    Out << I->first << " : " << I->second << NL;
+  }
+}
+
+void ProgramState::dumpTaint() const {
+  printTaint(llvm::errs());
+}
+
+//===----------------------------------------------------------------------===//
+// Generic Data Map.
+//===----------------------------------------------------------------------===//
+
+void *const* ProgramState::FindGDM(void *K) const {
+  return GDM.lookup(K);
+}
+
+void*
+ProgramStateManager::FindGDMContext(void *K,
+                               void *(*CreateContext)(llvm::BumpPtrAllocator&),
+                               void (*DeleteContext)(void*)) {
+
+  std::pair<void*, void (*)(void*)>& p = GDMContexts[K];
+  if (!p.first) {
+    p.first = CreateContext(Alloc);
+    p.second = DeleteContext;
+  }
+
+  return p.first;
+}
+
+ProgramStateRef ProgramStateManager::addGDM(ProgramStateRef St, void *Key, void *Data){
+  ProgramState::GenericDataMap M1 = St->getGDM();
+  ProgramState::GenericDataMap M2 = GDMFactory.add(M1, Key, Data);
+
+  if (M1 == M2)
+    return St;
+
+  ProgramState NewSt = *St;
+  NewSt.GDM = M2;
+  return getPersistentState(NewSt);
+}
+
+ProgramStateRef ProgramStateManager::removeGDM(ProgramStateRef state, void *Key) {
+  ProgramState::GenericDataMap OldM = state->getGDM();
+  ProgramState::GenericDataMap NewM = GDMFactory.remove(OldM, Key);
+
+  if (NewM == OldM)
+    return state;
+
+  ProgramState NewState = *state;
+  NewState.GDM = NewM;
+  return getPersistentState(NewState);
+}
+
+void ScanReachableSymbols::anchor() { }
+
+bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
+  for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I)
+    if (!scan(*I))
+      return false;
+
+  return true;
+}
+
+bool ScanReachableSymbols::scan(const SymExpr *sym) {
+  unsigned &isVisited = visited[sym];
+  if (isVisited)
+    return true;
+  isVisited = 1;
+  
+  if (!visitor.VisitSymbol(sym))
+    return false;
+  
+  // TODO: should be rewritten using SymExpr::symbol_iterator.
+  switch (sym->getKind()) {
+    case SymExpr::RegionValueKind:
+    case SymExpr::ConjuredKind:
+    case SymExpr::DerivedKind:
+    case SymExpr::ExtentKind:
+    case SymExpr::MetadataKind:
+      break;
+    case SymExpr::CastSymbolKind:
+      return scan(cast<SymbolCast>(sym)->getOperand());
+    case SymExpr::SymIntKind:
+      return scan(cast<SymIntExpr>(sym)->getLHS());
+    case SymExpr::IntSymKind:
+      return scan(cast<IntSymExpr>(sym)->getRHS());
+    case SymExpr::SymSymKind: {
+      const SymSymExpr *x = cast<SymSymExpr>(sym);
+      return scan(x->getLHS()) && scan(x->getRHS());
+    }
+  }
+  return true;
+}
+
+bool ScanReachableSymbols::scan(SVal val) {
+  if (loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(&val))
+    return scan(X->getRegion());
+
+  if (nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(&val))
+    return scan(X->getLoc());
+
+  if (SymbolRef Sym = val.getAsSymbol())
+    return scan(Sym);
+
+  if (const SymExpr *Sym = val.getAsSymbolicExpression())
+    return scan(Sym);
+
+  if (nonloc::CompoundVal *X = dyn_cast<nonloc::CompoundVal>(&val))
+    return scan(*X);
+
+  return true;
+}
+
+bool ScanReachableSymbols::scan(const MemRegion *R) {
+  if (isa<MemSpaceRegion>(R))
+    return true;
+  
+  unsigned &isVisited = visited[R];
+  if (isVisited)
+    return true;
+  isVisited = 1;
+  
+  
+  if (!visitor.VisitMemRegion(R))
+    return false;
+
+  // If this is a symbolic region, visit the symbol for the region.
+  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
+    if (!visitor.VisitSymbol(SR->getSymbol()))
+      return false;
+
+  // If this is a subregion, also visit the parent regions.
+  if (const SubRegion *SR = dyn_cast<SubRegion>(R))
+    if (!scan(SR->getSuperRegion()))
+      return false;
+
+  // Now look at the binding to this region (if any).
+  if (!scan(state->getSValAsScalarOrLoc(R)))
+    return false;
+
+  // Now look at the subregions.
+  if (!SRM.get())
+    SRM.reset(state->getStateManager().getStoreManager().
+                                           getSubRegionMap(state->getStore()));
+
+  return SRM->iterSubRegions(R, *this);
+}
+
+bool ProgramState::scanReachableSymbols(SVal val, SymbolVisitor& visitor) const {
+  ScanReachableSymbols S(this, visitor);
+  return S.scan(val);
+}
+
+bool ProgramState::scanReachableSymbols(const SVal *I, const SVal *E,
+                                   SymbolVisitor &visitor) const {
+  ScanReachableSymbols S(this, visitor);
+  for ( ; I != E; ++I) {
+    if (!S.scan(*I))
+      return false;
+  }
+  return true;
+}
+
+bool ProgramState::scanReachableSymbols(const MemRegion * const *I,
+                                   const MemRegion * const *E,
+                                   SymbolVisitor &visitor) const {
+  ScanReachableSymbols S(this, visitor);
+  for ( ; I != E; ++I) {
+    if (!S.scan(*I))
+      return false;
+  }
+  return true;
+}
+
+ProgramStateRef ProgramState::addTaint(const Stmt *S,
+                                           const LocationContext *LCtx,
+                                           TaintTagType Kind) const {
+  if (const Expr *E = dyn_cast_or_null<Expr>(S))
+    S = E->IgnoreParens();
+
+  SymbolRef Sym = getSVal(S, LCtx).getAsSymbol();
+  if (Sym)
+    return addTaint(Sym, Kind);
+
+  const MemRegion *R = getSVal(S, LCtx).getAsRegion();
+  addTaint(R, Kind);
+
+  // Cannot add taint, so just return the state.
+  return this;
+}
+
+ProgramStateRef ProgramState::addTaint(const MemRegion *R,
+                                           TaintTagType Kind) const {
+  if (const SymbolicRegion *SR = dyn_cast_or_null<SymbolicRegion>(R))
+    return addTaint(SR->getSymbol(), Kind);
+  return this;
+}
+
+ProgramStateRef ProgramState::addTaint(SymbolRef Sym,
+                                           TaintTagType Kind) const {
+  // If this is a symbol cast, remove the cast before adding the taint. Taint
+  // is cast agnostic.
+  while (const SymbolCast *SC = dyn_cast<SymbolCast>(Sym))
+    Sym = SC->getOperand();
+
+  ProgramStateRef NewState = set<TaintMap>(Sym, Kind);
+  assert(NewState);
+  return NewState;
+}
+
+bool ProgramState::isTainted(const Stmt *S, const LocationContext *LCtx,
+                             TaintTagType Kind) const {
+  if (const Expr *E = dyn_cast_or_null<Expr>(S))
+    S = E->IgnoreParens();
+
+  SVal val = getSVal(S, LCtx);
+  return isTainted(val, Kind);
+}
+
+bool ProgramState::isTainted(SVal V, TaintTagType Kind) const {
+  if (const SymExpr *Sym = V.getAsSymExpr())
+    return isTainted(Sym, Kind);
+  if (const MemRegion *Reg = V.getAsRegion())
+    return isTainted(Reg, Kind);
+  return false;
+}
+
+bool ProgramState::isTainted(const MemRegion *Reg, TaintTagType K) const {
+  if (!Reg)
+    return false;
+
+  // Element region (array element) is tainted if either the base or the offset
+  // are tainted.
+  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Reg))
+    return isTainted(ER->getSuperRegion(), K) || isTainted(ER->getIndex(), K);
+
+  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Reg))
+    return isTainted(SR->getSymbol(), K);
+
+  if (const SubRegion *ER = dyn_cast<SubRegion>(Reg))
+    return isTainted(ER->getSuperRegion(), K);
+
+  return false;
+}
+
+bool ProgramState::isTainted(SymbolRef Sym, TaintTagType Kind) const {
+  if (!Sym)
+    return false;
+  
+  // Traverse all the symbols this symbol depends on to see if any are tainted.
+  bool Tainted = false;
+  for (SymExpr::symbol_iterator SI = Sym->symbol_begin(), SE =Sym->symbol_end();
+       SI != SE; ++SI) {
+    assert(isa<SymbolData>(*SI));
+    const TaintTagType *Tag = get<TaintMap>(*SI);
+    Tainted = (Tag && *Tag == Kind);
+
+    // If this is a SymbolDerived with a tainted parent, it's also tainted.
+    if (const SymbolDerived *SD = dyn_cast<SymbolDerived>(*SI))
+      Tainted = Tainted || isTainted(SD->getParentSymbol(), Kind);
+
+    // If memory region is tainted, data is also tainted.
+    if (const SymbolRegionValue *SRV = dyn_cast<SymbolRegionValue>(*SI))
+      Tainted = Tainted || isTainted(SRV->getRegion(), Kind);
+
+    // If If this is a SymbolCast from a tainted value, it's also tainted.
+    if (const SymbolCast *SC = dyn_cast<SymbolCast>(*SI))
+      Tainted = Tainted || isTainted(SC->getOperand(), Kind);
+
+    if (Tainted)
+      return true;
+  }
+  
+  return Tainted;
+}