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1 // SValBuilder.cpp - Basic class for all SValBuilder implementations -*- 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 defines SValBuilder, the base class for all (complete) SValBuilder
11 //  implementations.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
21 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
22 
23 using namespace clang;
24 using namespace ento;
25 
26 //===----------------------------------------------------------------------===//
27 // Basic SVal creation.
28 //===----------------------------------------------------------------------===//
29 
anchor()30 void SValBuilder::anchor() { }
31 
makeZeroVal(QualType type)32 DefinedOrUnknownSVal SValBuilder::makeZeroVal(QualType type) {
33   if (Loc::isLocType(type))
34     return makeNull();
35 
36   if (type->isIntegralOrEnumerationType())
37     return makeIntVal(0, type);
38 
39   // FIXME: Handle floats.
40   // FIXME: Handle structs.
41   return UnknownVal();
42 }
43 
makeNonLoc(const SymExpr * lhs,BinaryOperator::Opcode op,const llvm::APSInt & rhs,QualType type)44 NonLoc SValBuilder::makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
45                                 const llvm::APSInt& rhs, QualType type) {
46   // The Environment ensures we always get a persistent APSInt in
47   // BasicValueFactory, so we don't need to get the APSInt from
48   // BasicValueFactory again.
49   assert(lhs);
50   assert(!Loc::isLocType(type));
51   return nonloc::SymbolVal(SymMgr.getSymIntExpr(lhs, op, rhs, type));
52 }
53 
makeNonLoc(const llvm::APSInt & lhs,BinaryOperator::Opcode op,const SymExpr * rhs,QualType type)54 NonLoc SValBuilder::makeNonLoc(const llvm::APSInt& lhs,
55                                BinaryOperator::Opcode op, const SymExpr *rhs,
56                                QualType type) {
57   assert(rhs);
58   assert(!Loc::isLocType(type));
59   return nonloc::SymbolVal(SymMgr.getIntSymExpr(lhs, op, rhs, type));
60 }
61 
makeNonLoc(const SymExpr * lhs,BinaryOperator::Opcode op,const SymExpr * rhs,QualType type)62 NonLoc SValBuilder::makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
63                                const SymExpr *rhs, QualType type) {
64   assert(lhs && rhs);
65   assert(!Loc::isLocType(type));
66   return nonloc::SymbolVal(SymMgr.getSymSymExpr(lhs, op, rhs, type));
67 }
68 
makeNonLoc(const SymExpr * operand,QualType fromTy,QualType toTy)69 NonLoc SValBuilder::makeNonLoc(const SymExpr *operand,
70                                QualType fromTy, QualType toTy) {
71   assert(operand);
72   assert(!Loc::isLocType(toTy));
73   return nonloc::SymbolVal(SymMgr.getCastSymbol(operand, fromTy, toTy));
74 }
75 
convertToArrayIndex(SVal val)76 SVal SValBuilder::convertToArrayIndex(SVal val) {
77   if (val.isUnknownOrUndef())
78     return val;
79 
80   // Common case: we have an appropriately sized integer.
81   if (Optional<nonloc::ConcreteInt> CI = val.getAs<nonloc::ConcreteInt>()) {
82     const llvm::APSInt& I = CI->getValue();
83     if (I.getBitWidth() == ArrayIndexWidth && I.isSigned())
84       return val;
85   }
86 
87   return evalCastFromNonLoc(val.castAs<NonLoc>(), ArrayIndexTy);
88 }
89 
makeBoolVal(const CXXBoolLiteralExpr * boolean)90 nonloc::ConcreteInt SValBuilder::makeBoolVal(const CXXBoolLiteralExpr *boolean){
91   return makeTruthVal(boolean->getValue());
92 }
93 
94 DefinedOrUnknownSVal
getRegionValueSymbolVal(const TypedValueRegion * region)95 SValBuilder::getRegionValueSymbolVal(const TypedValueRegion* region) {
96   QualType T = region->getValueType();
97 
98   if (T->isNullPtrType())
99     return makeZeroVal(T);
100 
101   if (!SymbolManager::canSymbolicate(T))
102     return UnknownVal();
103 
104   SymbolRef sym = SymMgr.getRegionValueSymbol(region);
105 
106   if (Loc::isLocType(T))
107     return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
108 
109   return nonloc::SymbolVal(sym);
110 }
111 
conjureSymbolVal(const void * SymbolTag,const Expr * Ex,const LocationContext * LCtx,unsigned Count)112 DefinedOrUnknownSVal SValBuilder::conjureSymbolVal(const void *SymbolTag,
113                                                    const Expr *Ex,
114                                                    const LocationContext *LCtx,
115                                                    unsigned Count) {
116   QualType T = Ex->getType();
117 
118   if (T->isNullPtrType())
119     return makeZeroVal(T);
120 
121   // Compute the type of the result. If the expression is not an R-value, the
122   // result should be a location.
123   QualType ExType = Ex->getType();
124   if (Ex->isGLValue())
125     T = LCtx->getAnalysisDeclContext()->getASTContext().getPointerType(ExType);
126 
127   return conjureSymbolVal(SymbolTag, Ex, LCtx, T, Count);
128 }
129 
conjureSymbolVal(const void * symbolTag,const Expr * expr,const LocationContext * LCtx,QualType type,unsigned count)130 DefinedOrUnknownSVal SValBuilder::conjureSymbolVal(const void *symbolTag,
131                                                    const Expr *expr,
132                                                    const LocationContext *LCtx,
133                                                    QualType type,
134                                                    unsigned count) {
135   if (type->isNullPtrType())
136     return makeZeroVal(type);
137 
138   if (!SymbolManager::canSymbolicate(type))
139     return UnknownVal();
140 
141   SymbolRef sym = SymMgr.conjureSymbol(expr, LCtx, type, count, symbolTag);
142 
143   if (Loc::isLocType(type))
144     return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
145 
146   return nonloc::SymbolVal(sym);
147 }
148 
149 
conjureSymbolVal(const Stmt * stmt,const LocationContext * LCtx,QualType type,unsigned visitCount)150 DefinedOrUnknownSVal SValBuilder::conjureSymbolVal(const Stmt *stmt,
151                                                    const LocationContext *LCtx,
152                                                    QualType type,
153                                                    unsigned visitCount) {
154   if (type->isNullPtrType())
155     return makeZeroVal(type);
156 
157   if (!SymbolManager::canSymbolicate(type))
158     return UnknownVal();
159 
160   SymbolRef sym = SymMgr.conjureSymbol(stmt, LCtx, type, visitCount);
161 
162   if (Loc::isLocType(type))
163     return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
164 
165   return nonloc::SymbolVal(sym);
166 }
167 
168 DefinedOrUnknownSVal
getConjuredHeapSymbolVal(const Expr * E,const LocationContext * LCtx,unsigned VisitCount)169 SValBuilder::getConjuredHeapSymbolVal(const Expr *E,
170                                       const LocationContext *LCtx,
171                                       unsigned VisitCount) {
172   QualType T = E->getType();
173   assert(Loc::isLocType(T));
174   assert(SymbolManager::canSymbolicate(T));
175   if (T->isNullPtrType())
176     return makeZeroVal(T);
177 
178   SymbolRef sym = SymMgr.conjureSymbol(E, LCtx, T, VisitCount);
179   return loc::MemRegionVal(MemMgr.getSymbolicHeapRegion(sym));
180 }
181 
getMetadataSymbolVal(const void * symbolTag,const MemRegion * region,const Expr * expr,QualType type,unsigned count)182 DefinedSVal SValBuilder::getMetadataSymbolVal(const void *symbolTag,
183                                               const MemRegion *region,
184                                               const Expr *expr, QualType type,
185                                               unsigned count) {
186   assert(SymbolManager::canSymbolicate(type) && "Invalid metadata symbol type");
187 
188   SymbolRef sym =
189       SymMgr.getMetadataSymbol(region, expr, type, count, symbolTag);
190 
191   if (Loc::isLocType(type))
192     return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
193 
194   return nonloc::SymbolVal(sym);
195 }
196 
197 DefinedOrUnknownSVal
getDerivedRegionValueSymbolVal(SymbolRef parentSymbol,const TypedValueRegion * region)198 SValBuilder::getDerivedRegionValueSymbolVal(SymbolRef parentSymbol,
199                                              const TypedValueRegion *region) {
200   QualType T = region->getValueType();
201 
202   if (T->isNullPtrType())
203     return makeZeroVal(T);
204 
205   if (!SymbolManager::canSymbolicate(T))
206     return UnknownVal();
207 
208   SymbolRef sym = SymMgr.getDerivedSymbol(parentSymbol, region);
209 
210   if (Loc::isLocType(T))
211     return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
212 
213   return nonloc::SymbolVal(sym);
214 }
215 
getFunctionPointer(const FunctionDecl * func)216 DefinedSVal SValBuilder::getFunctionPointer(const FunctionDecl *func) {
217   return loc::MemRegionVal(MemMgr.getFunctionTextRegion(func));
218 }
219 
getBlockPointer(const BlockDecl * block,CanQualType locTy,const LocationContext * locContext,unsigned blockCount)220 DefinedSVal SValBuilder::getBlockPointer(const BlockDecl *block,
221                                          CanQualType locTy,
222                                          const LocationContext *locContext,
223                                          unsigned blockCount) {
224   const BlockTextRegion *BC =
225     MemMgr.getBlockTextRegion(block, locTy, locContext->getAnalysisDeclContext());
226   const BlockDataRegion *BD = MemMgr.getBlockDataRegion(BC, locContext,
227                                                         blockCount);
228   return loc::MemRegionVal(BD);
229 }
230 
231 /// Return a memory region for the 'this' object reference.
getCXXThis(const CXXMethodDecl * D,const StackFrameContext * SFC)232 loc::MemRegionVal SValBuilder::getCXXThis(const CXXMethodDecl *D,
233                                           const StackFrameContext *SFC) {
234   return loc::MemRegionVal(getRegionManager().
235                            getCXXThisRegion(D->getThisType(getContext()), SFC));
236 }
237 
238 /// Return a memory region for the 'this' object reference.
getCXXThis(const CXXRecordDecl * D,const StackFrameContext * SFC)239 loc::MemRegionVal SValBuilder::getCXXThis(const CXXRecordDecl *D,
240                                           const StackFrameContext *SFC) {
241   const Type *T = D->getTypeForDecl();
242   QualType PT = getContext().getPointerType(QualType(T, 0));
243   return loc::MemRegionVal(getRegionManager().getCXXThisRegion(PT, SFC));
244 }
245 
getConstantVal(const Expr * E)246 Optional<SVal> SValBuilder::getConstantVal(const Expr *E) {
247   E = E->IgnoreParens();
248 
249   switch (E->getStmtClass()) {
250   // Handle expressions that we treat differently from the AST's constant
251   // evaluator.
252   case Stmt::AddrLabelExprClass:
253     return makeLoc(cast<AddrLabelExpr>(E));
254 
255   case Stmt::CXXScalarValueInitExprClass:
256   case Stmt::ImplicitValueInitExprClass:
257     return makeZeroVal(E->getType());
258 
259   case Stmt::ObjCStringLiteralClass: {
260     const ObjCStringLiteral *SL = cast<ObjCStringLiteral>(E);
261     return makeLoc(getRegionManager().getObjCStringRegion(SL));
262   }
263 
264   case Stmt::StringLiteralClass: {
265     const StringLiteral *SL = cast<StringLiteral>(E);
266     return makeLoc(getRegionManager().getStringRegion(SL));
267   }
268 
269   // Fast-path some expressions to avoid the overhead of going through the AST's
270   // constant evaluator
271   case Stmt::CharacterLiteralClass: {
272     const CharacterLiteral *C = cast<CharacterLiteral>(E);
273     return makeIntVal(C->getValue(), C->getType());
274   }
275 
276   case Stmt::CXXBoolLiteralExprClass:
277     return makeBoolVal(cast<CXXBoolLiteralExpr>(E));
278 
279   case Stmt::TypeTraitExprClass: {
280     const TypeTraitExpr *TE = cast<TypeTraitExpr>(E);
281     return makeTruthVal(TE->getValue(), TE->getType());
282   }
283 
284   case Stmt::IntegerLiteralClass:
285     return makeIntVal(cast<IntegerLiteral>(E));
286 
287   case Stmt::ObjCBoolLiteralExprClass:
288     return makeBoolVal(cast<ObjCBoolLiteralExpr>(E));
289 
290   case Stmt::CXXNullPtrLiteralExprClass:
291     return makeNull();
292 
293   case Stmt::ImplicitCastExprClass: {
294     const CastExpr *CE = cast<CastExpr>(E);
295     switch (CE->getCastKind()) {
296     default:
297       break;
298     case CK_ArrayToPointerDecay:
299     case CK_BitCast: {
300       const Expr *SE = CE->getSubExpr();
301       Optional<SVal> Val = getConstantVal(SE);
302       if (!Val)
303         return None;
304       return evalCast(*Val, CE->getType(), SE->getType());
305     }
306     }
307     // FALLTHROUGH
308   }
309 
310   // If we don't have a special case, fall back to the AST's constant evaluator.
311   default: {
312     // Don't try to come up with a value for materialized temporaries.
313     if (E->isGLValue())
314       return None;
315 
316     ASTContext &Ctx = getContext();
317     llvm::APSInt Result;
318     if (E->EvaluateAsInt(Result, Ctx))
319       return makeIntVal(Result);
320 
321     if (Loc::isLocType(E->getType()))
322       if (E->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull))
323         return makeNull();
324 
325     return None;
326   }
327   }
328 }
329 
330 //===----------------------------------------------------------------------===//
331 
makeSymExprValNN(ProgramStateRef State,BinaryOperator::Opcode Op,NonLoc LHS,NonLoc RHS,QualType ResultTy)332 SVal SValBuilder::makeSymExprValNN(ProgramStateRef State,
333                                    BinaryOperator::Opcode Op,
334                                    NonLoc LHS, NonLoc RHS,
335                                    QualType ResultTy) {
336   if (!State->isTainted(RHS) && !State->isTainted(LHS))
337     return UnknownVal();
338 
339   const SymExpr *symLHS = LHS.getAsSymExpr();
340   const SymExpr *symRHS = RHS.getAsSymExpr();
341   // TODO: When the Max Complexity is reached, we should conjure a symbol
342   // instead of generating an Unknown value and propagate the taint info to it.
343   const unsigned MaxComp = 10000; // 100000 28X
344 
345   if (symLHS && symRHS &&
346       (symLHS->computeComplexity() + symRHS->computeComplexity()) <  MaxComp)
347     return makeNonLoc(symLHS, Op, symRHS, ResultTy);
348 
349   if (symLHS && symLHS->computeComplexity() < MaxComp)
350     if (Optional<nonloc::ConcreteInt> rInt = RHS.getAs<nonloc::ConcreteInt>())
351       return makeNonLoc(symLHS, Op, rInt->getValue(), ResultTy);
352 
353   if (symRHS && symRHS->computeComplexity() < MaxComp)
354     if (Optional<nonloc::ConcreteInt> lInt = LHS.getAs<nonloc::ConcreteInt>())
355       return makeNonLoc(lInt->getValue(), Op, symRHS, ResultTy);
356 
357   return UnknownVal();
358 }
359 
360 
evalBinOp(ProgramStateRef state,BinaryOperator::Opcode op,SVal lhs,SVal rhs,QualType type)361 SVal SValBuilder::evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
362                             SVal lhs, SVal rhs, QualType type) {
363 
364   if (lhs.isUndef() || rhs.isUndef())
365     return UndefinedVal();
366 
367   if (lhs.isUnknown() || rhs.isUnknown())
368     return UnknownVal();
369 
370   if (Optional<Loc> LV = lhs.getAs<Loc>()) {
371     if (Optional<Loc> RV = rhs.getAs<Loc>())
372       return evalBinOpLL(state, op, *LV, *RV, type);
373 
374     return evalBinOpLN(state, op, *LV, rhs.castAs<NonLoc>(), type);
375   }
376 
377   if (Optional<Loc> RV = rhs.getAs<Loc>()) {
378     // Support pointer arithmetic where the addend is on the left
379     // and the pointer on the right.
380     assert(op == BO_Add);
381 
382     // Commute the operands.
383     return evalBinOpLN(state, op, *RV, lhs.castAs<NonLoc>(), type);
384   }
385 
386   return evalBinOpNN(state, op, lhs.castAs<NonLoc>(), rhs.castAs<NonLoc>(),
387                      type);
388 }
389 
evalEQ(ProgramStateRef state,DefinedOrUnknownSVal lhs,DefinedOrUnknownSVal rhs)390 DefinedOrUnknownSVal SValBuilder::evalEQ(ProgramStateRef state,
391                                          DefinedOrUnknownSVal lhs,
392                                          DefinedOrUnknownSVal rhs) {
393   return evalBinOp(state, BO_EQ, lhs, rhs, getConditionType())
394       .castAs<DefinedOrUnknownSVal>();
395 }
396 
397 /// Recursively check if the pointer types are equal modulo const, volatile,
398 /// and restrict qualifiers. Also, assume that all types are similar to 'void'.
399 /// Assumes the input types are canonical.
shouldBeModeledWithNoOp(ASTContext & Context,QualType ToTy,QualType FromTy)400 static bool shouldBeModeledWithNoOp(ASTContext &Context, QualType ToTy,
401                                                          QualType FromTy) {
402   while (Context.UnwrapSimilarPointerTypes(ToTy, FromTy)) {
403     Qualifiers Quals1, Quals2;
404     ToTy = Context.getUnqualifiedArrayType(ToTy, Quals1);
405     FromTy = Context.getUnqualifiedArrayType(FromTy, Quals2);
406 
407     // Make sure that non-cvr-qualifiers the other qualifiers (e.g., address
408     // spaces) are identical.
409     Quals1.removeCVRQualifiers();
410     Quals2.removeCVRQualifiers();
411     if (Quals1 != Quals2)
412       return false;
413   }
414 
415   // If we are casting to void, the 'From' value can be used to represent the
416   // 'To' value.
417   if (ToTy->isVoidType())
418     return true;
419 
420   if (ToTy != FromTy)
421     return false;
422 
423   return true;
424 }
425 
426 // FIXME: should rewrite according to the cast kind.
evalCast(SVal val,QualType castTy,QualType originalTy)427 SVal SValBuilder::evalCast(SVal val, QualType castTy, QualType originalTy) {
428   castTy = Context.getCanonicalType(castTy);
429   originalTy = Context.getCanonicalType(originalTy);
430   if (val.isUnknownOrUndef() || castTy == originalTy)
431     return val;
432 
433   if (castTy->isBooleanType()) {
434     if (val.isUnknownOrUndef())
435       return val;
436     if (val.isConstant())
437       return makeTruthVal(!val.isZeroConstant(), castTy);
438     if (!Loc::isLocType(originalTy) &&
439         !originalTy->isIntegralOrEnumerationType() &&
440         !originalTy->isMemberPointerType())
441       return UnknownVal();
442     if (SymbolRef Sym = val.getAsSymbol(true)) {
443       BasicValueFactory &BVF = getBasicValueFactory();
444       // FIXME: If we had a state here, we could see if the symbol is known to
445       // be zero, but we don't.
446       return makeNonLoc(Sym, BO_NE, BVF.getValue(0, Sym->getType()), castTy);
447     }
448     // Loc values are not always true, they could be weakly linked functions.
449     if (Optional<Loc> L = val.getAs<Loc>())
450       return evalCastFromLoc(*L, castTy);
451 
452     Loc L = val.castAs<nonloc::LocAsInteger>().getLoc();
453     return evalCastFromLoc(L, castTy);
454   }
455 
456   // For const casts, casts to void, just propagate the value.
457   if (!castTy->isVariableArrayType() && !originalTy->isVariableArrayType())
458     if (shouldBeModeledWithNoOp(Context, Context.getPointerType(castTy),
459                                          Context.getPointerType(originalTy)))
460       return val;
461 
462   // Check for casts from pointers to integers.
463   if (castTy->isIntegralOrEnumerationType() && Loc::isLocType(originalTy))
464     return evalCastFromLoc(val.castAs<Loc>(), castTy);
465 
466   // Check for casts from integers to pointers.
467   if (Loc::isLocType(castTy) && originalTy->isIntegralOrEnumerationType()) {
468     if (Optional<nonloc::LocAsInteger> LV = val.getAs<nonloc::LocAsInteger>()) {
469       if (const MemRegion *R = LV->getLoc().getAsRegion()) {
470         StoreManager &storeMgr = StateMgr.getStoreManager();
471         R = storeMgr.castRegion(R, castTy);
472         return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
473       }
474       return LV->getLoc();
475     }
476     return dispatchCast(val, castTy);
477   }
478 
479   // Just pass through function and block pointers.
480   if (originalTy->isBlockPointerType() || originalTy->isFunctionPointerType()) {
481     assert(Loc::isLocType(castTy));
482     return val;
483   }
484 
485   // Check for casts from array type to another type.
486   if (const ArrayType *arrayT =
487                       dyn_cast<ArrayType>(originalTy.getCanonicalType())) {
488     // We will always decay to a pointer.
489     QualType elemTy = arrayT->getElementType();
490     val = StateMgr.ArrayToPointer(val.castAs<Loc>(), elemTy);
491 
492     // Are we casting from an array to a pointer?  If so just pass on
493     // the decayed value.
494     if (castTy->isPointerType() || castTy->isReferenceType())
495       return val;
496 
497     // Are we casting from an array to an integer?  If so, cast the decayed
498     // pointer value to an integer.
499     assert(castTy->isIntegralOrEnumerationType());
500 
501     // FIXME: Keep these here for now in case we decide soon that we
502     // need the original decayed type.
503     //    QualType elemTy = cast<ArrayType>(originalTy)->getElementType();
504     //    QualType pointerTy = C.getPointerType(elemTy);
505     return evalCastFromLoc(val.castAs<Loc>(), castTy);
506   }
507 
508   // Check for casts from a region to a specific type.
509   if (const MemRegion *R = val.getAsRegion()) {
510     // Handle other casts of locations to integers.
511     if (castTy->isIntegralOrEnumerationType())
512       return evalCastFromLoc(loc::MemRegionVal(R), castTy);
513 
514     // FIXME: We should handle the case where we strip off view layers to get
515     //  to a desugared type.
516     if (!Loc::isLocType(castTy)) {
517       // FIXME: There can be gross cases where one casts the result of a function
518       // (that returns a pointer) to some other value that happens to fit
519       // within that pointer value.  We currently have no good way to
520       // model such operations.  When this happens, the underlying operation
521       // is that the caller is reasoning about bits.  Conceptually we are
522       // layering a "view" of a location on top of those bits.  Perhaps
523       // we need to be more lazy about mutual possible views, even on an
524       // SVal?  This may be necessary for bit-level reasoning as well.
525       return UnknownVal();
526     }
527 
528     // We get a symbolic function pointer for a dereference of a function
529     // pointer, but it is of function type. Example:
530 
531     //  struct FPRec {
532     //    void (*my_func)(int * x);
533     //  };
534     //
535     //  int bar(int x);
536     //
537     //  int f1_a(struct FPRec* foo) {
538     //    int x;
539     //    (*foo->my_func)(&x);
540     //    return bar(x)+1; // no-warning
541     //  }
542 
543     assert(Loc::isLocType(originalTy) || originalTy->isFunctionType() ||
544            originalTy->isBlockPointerType() || castTy->isReferenceType());
545 
546     StoreManager &storeMgr = StateMgr.getStoreManager();
547 
548     // Delegate to store manager to get the result of casting a region to a
549     // different type.  If the MemRegion* returned is NULL, this expression
550     // Evaluates to UnknownVal.
551     R = storeMgr.castRegion(R, castTy);
552     return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
553   }
554 
555   return dispatchCast(val, castTy);
556 }
557