1 //== Store.cpp - Interface for maps from Locations to Values ----*- C++ -*--==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defined the types Store and StoreManager.
12 //===----------------------------------------------------------------------===//
14 #include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"
15 #include "clang/AST/CXXInheritance.h"
16 #include "clang/AST/CharUnits.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
21 using namespace clang;
24 StoreManager::StoreManager(ProgramStateManager &stateMgr)
25 : svalBuilder(stateMgr.getSValBuilder()), StateMgr(stateMgr),
26 MRMgr(svalBuilder.getRegionManager()), Ctx(stateMgr.getContext()) {}
28 StoreRef StoreManager::enterStackFrame(Store OldStore,
29 const CallEvent &Call,
30 const StackFrameContext *LCtx) {
31 StoreRef Store = StoreRef(OldStore, *this);
33 SmallVector<CallEvent::FrameBindingTy, 16> InitialBindings;
34 Call.getInitialStackFrameContents(LCtx, InitialBindings);
36 for (CallEvent::BindingsTy::iterator I = InitialBindings.begin(),
37 E = InitialBindings.end();
39 Store = Bind(Store.getStore(), I->first, I->second);
45 const MemRegion *StoreManager::MakeElementRegion(const MemRegion *Base,
46 QualType EleTy, uint64_t index) {
47 NonLoc idx = svalBuilder.makeArrayIndex(index);
48 return MRMgr.getElementRegion(EleTy, idx, Base, svalBuilder.getContext());
51 // FIXME: Merge with the implementation of the same method in MemRegion.cpp
52 static bool IsCompleteType(ASTContext &Ctx, QualType Ty) {
53 if (const RecordType *RT = Ty->getAs<RecordType>()) {
54 const RecordDecl *D = RT->getDecl();
55 if (!D->getDefinition())
62 StoreRef StoreManager::BindDefault(Store store, const MemRegion *R, SVal V) {
63 return StoreRef(store, *this);
66 const ElementRegion *StoreManager::GetElementZeroRegion(const MemRegion *R,
68 NonLoc idx = svalBuilder.makeZeroArrayIndex();
70 return MRMgr.getElementRegion(T, idx, R, Ctx);
73 const MemRegion *StoreManager::castRegion(const MemRegion *R, QualType CastToTy) {
75 ASTContext &Ctx = StateMgr.getContext();
77 // Handle casts to Objective-C objects.
78 if (CastToTy->isObjCObjectPointerType())
79 return R->StripCasts();
81 if (CastToTy->isBlockPointerType()) {
82 // FIXME: We may need different solutions, depending on the symbol
83 // involved. Blocks can be casted to/from 'id', as they can be treated
84 // as Objective-C objects. This could possibly be handled by enhancing
85 // our reasoning of downcasts of symbolic objects.
86 if (isa<CodeTextRegion>(R) || isa<SymbolicRegion>(R))
89 // We don't know what to make of it. Return a NULL region, which
90 // will be interpretted as UnknownVal.
94 // Now assume we are casting from pointer to pointer. Other cases should
95 // already be handled.
96 QualType PointeeTy = CastToTy->getPointeeType();
97 QualType CanonPointeeTy = Ctx.getCanonicalType(PointeeTy);
99 // Handle casts to void*. We just pass the region through.
100 if (CanonPointeeTy.getLocalUnqualifiedType() == Ctx.VoidTy)
103 // Handle casts from compatible types.
104 if (R->isBoundable())
105 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) {
106 QualType ObjTy = Ctx.getCanonicalType(TR->getValueType());
107 if (CanonPointeeTy == ObjTy)
111 // Process region cast according to the kind of the region being cast.
112 switch (R->getKind()) {
113 case MemRegion::CXXThisRegionKind:
114 case MemRegion::GenericMemSpaceRegionKind:
115 case MemRegion::StackLocalsSpaceRegionKind:
116 case MemRegion::StackArgumentsSpaceRegionKind:
117 case MemRegion::HeapSpaceRegionKind:
118 case MemRegion::UnknownSpaceRegionKind:
119 case MemRegion::StaticGlobalSpaceRegionKind:
120 case MemRegion::GlobalInternalSpaceRegionKind:
121 case MemRegion::GlobalSystemSpaceRegionKind:
122 case MemRegion::GlobalImmutableSpaceRegionKind: {
123 llvm_unreachable("Invalid region cast");
126 case MemRegion::FunctionTextRegionKind:
127 case MemRegion::BlockTextRegionKind:
128 case MemRegion::BlockDataRegionKind:
129 case MemRegion::StringRegionKind:
130 // FIXME: Need to handle arbitrary downcasts.
131 case MemRegion::SymbolicRegionKind:
132 case MemRegion::AllocaRegionKind:
133 case MemRegion::CompoundLiteralRegionKind:
134 case MemRegion::FieldRegionKind:
135 case MemRegion::ObjCIvarRegionKind:
136 case MemRegion::ObjCStringRegionKind:
137 case MemRegion::VarRegionKind:
138 case MemRegion::CXXTempObjectRegionKind:
139 case MemRegion::CXXBaseObjectRegionKind:
140 return MakeElementRegion(R, PointeeTy);
142 case MemRegion::ElementRegionKind: {
143 // If we are casting from an ElementRegion to another type, the
144 // algorithm is as follows:
146 // (1) Compute the "raw offset" of the ElementRegion from the
147 // base region. This is done by calling 'getAsRawOffset()'.
149 // (2a) If we get a 'RegionRawOffset' after calling
150 // 'getAsRawOffset()', determine if the absolute offset
151 // can be exactly divided into chunks of the size of the
152 // casted-pointee type. If so, create a new ElementRegion with
153 // the pointee-cast type as the new ElementType and the index
154 // being the offset divded by the chunk size. If not, create
155 // a new ElementRegion at offset 0 off the raw offset region.
157 // (2b) If we don't a get a 'RegionRawOffset' after calling
158 // 'getAsRawOffset()', it means that we are at offset 0.
160 // FIXME: Handle symbolic raw offsets.
162 const ElementRegion *elementR = cast<ElementRegion>(R);
163 const RegionRawOffset &rawOff = elementR->getAsArrayOffset();
164 const MemRegion *baseR = rawOff.getRegion();
166 // If we cannot compute a raw offset, throw up our hands and return
167 // a NULL MemRegion*.
171 CharUnits off = rawOff.getOffset();
174 // Edge case: we are at 0 bytes off the beginning of baseR. We
175 // check to see if type we are casting to is the same as the base
176 // region. If so, just return the base region.
177 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(baseR)) {
178 QualType ObjTy = Ctx.getCanonicalType(TR->getValueType());
179 QualType CanonPointeeTy = Ctx.getCanonicalType(PointeeTy);
180 if (CanonPointeeTy == ObjTy)
184 // Otherwise, create a new ElementRegion at offset 0.
185 return MakeElementRegion(baseR, PointeeTy);
188 // We have a non-zero offset from the base region. We want to determine
189 // if the offset can be evenly divided by sizeof(PointeeTy). If so,
190 // we create an ElementRegion whose index is that value. Otherwise, we
191 // create two ElementRegions, one that reflects a raw offset and the other
192 // that reflects the cast.
194 // Compute the index for the new ElementRegion.
195 int64_t newIndex = 0;
196 const MemRegion *newSuperR = 0;
198 // We can only compute sizeof(PointeeTy) if it is a complete type.
199 if (IsCompleteType(Ctx, PointeeTy)) {
200 // Compute the size in **bytes**.
201 CharUnits pointeeTySize = Ctx.getTypeSizeInChars(PointeeTy);
202 if (!pointeeTySize.isZero()) {
203 // Is the offset a multiple of the size? If so, we can layer the
204 // ElementRegion (with elementType == PointeeTy) directly on top of
206 if (off % pointeeTySize == 0) {
207 newIndex = off / pointeeTySize;
214 // Create an intermediate ElementRegion to represent the raw byte.
215 // This will be the super region of the final ElementRegion.
216 newSuperR = MakeElementRegion(baseR, Ctx.CharTy, off.getQuantity());
219 return MakeElementRegion(newSuperR, PointeeTy, newIndex);
223 llvm_unreachable("unreachable");
226 static bool regionMatchesCXXRecordType(SVal V, QualType Ty) {
227 const MemRegion *MR = V.getAsRegion();
231 const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(MR);
235 const CXXRecordDecl *RD = TVR->getValueType()->getAsCXXRecordDecl();
239 const CXXRecordDecl *Expected = Ty->getPointeeCXXRecordDecl();
241 Expected = Ty->getAsCXXRecordDecl();
243 return Expected->getCanonicalDecl() == RD->getCanonicalDecl();
246 SVal StoreManager::evalDerivedToBase(SVal Derived, const CastExpr *Cast) {
247 // Sanity check to avoid doing the wrong thing in the face of
249 if (!regionMatchesCXXRecordType(Derived, Cast->getSubExpr()->getType()))
252 // Walk through the cast path to create nested CXXBaseRegions.
253 SVal Result = Derived;
254 for (CastExpr::path_const_iterator I = Cast->path_begin(),
255 E = Cast->path_end();
257 Result = evalDerivedToBase(Result, (*I)->getType(), (*I)->isVirtual());
262 SVal StoreManager::evalDerivedToBase(SVal Derived, const CXXBasePath &Path) {
263 // Walk through the path to create nested CXXBaseRegions.
264 SVal Result = Derived;
265 for (CXXBasePath::const_iterator I = Path.begin(), E = Path.end();
267 Result = evalDerivedToBase(Result, I->Base->getType(),
268 I->Base->isVirtual());
273 SVal StoreManager::evalDerivedToBase(SVal Derived, QualType BaseType,
275 Optional<loc::MemRegionVal> DerivedRegVal =
276 Derived.getAs<loc::MemRegionVal>();
280 const CXXRecordDecl *BaseDecl = BaseType->getPointeeCXXRecordDecl();
282 BaseDecl = BaseType->getAsCXXRecordDecl();
283 assert(BaseDecl && "not a C++ object?");
285 const MemRegion *BaseReg =
286 MRMgr.getCXXBaseObjectRegion(BaseDecl, DerivedRegVal->getRegion(),
289 return loc::MemRegionVal(BaseReg);
292 /// Returns the static type of the given region, if it represents a C++ class
295 /// This handles both fully-typed regions, where the dynamic type is known, and
296 /// symbolic regions, where the dynamic type is merely bounded (and even then,
297 /// only ostensibly!), but does not take advantage of any dynamic type info.
298 static const CXXRecordDecl *getCXXRecordType(const MemRegion *MR) {
299 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(MR))
300 return TVR->getValueType()->getAsCXXRecordDecl();
301 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
302 return SR->getSymbol()->getType()->getPointeeCXXRecordDecl();
306 SVal StoreManager::evalDynamicCast(SVal Base, QualType TargetType,
310 const MemRegion *MR = Base.getAsRegion();
314 // Assume the derived class is a pointer or a reference to a CXX record.
315 TargetType = TargetType->getPointeeType();
316 assert(!TargetType.isNull());
317 const CXXRecordDecl *TargetClass = TargetType->getAsCXXRecordDecl();
318 if (!TargetClass && !TargetType->isVoidType())
321 // Drill down the CXXBaseObject chains, which represent upcasts (casts from
323 while (const CXXRecordDecl *MRClass = getCXXRecordType(MR)) {
324 // If found the derived class, the cast succeeds.
325 if (MRClass == TargetClass)
326 return loc::MemRegionVal(MR);
328 // We skip over incomplete types. They must be the result of an earlier
329 // reinterpret_cast, as one can only dynamic_cast between types in the same
331 if (!TargetType->isVoidType() && MRClass->hasDefinition()) {
332 // Static upcasts are marked as DerivedToBase casts by Sema, so this will
333 // only happen when multiple or virtual inheritance is involved.
334 CXXBasePaths Paths(/*FindAmbiguities=*/false, /*RecordPaths=*/true,
335 /*DetectVirtual=*/false);
336 if (MRClass->isDerivedFrom(TargetClass, Paths))
337 return evalDerivedToBase(loc::MemRegionVal(MR), Paths.front());
340 if (const CXXBaseObjectRegion *BaseR = dyn_cast<CXXBaseObjectRegion>(MR)) {
341 // Drill down the chain to get the derived classes.
342 MR = BaseR->getSuperRegion();
346 // If this is a cast to void*, return the region.
347 if (TargetType->isVoidType())
348 return loc::MemRegionVal(MR);
350 // Strange use of reinterpret_cast can give us paths we don't reason
351 // about well, by putting in ElementRegions where we'd expect
352 // CXXBaseObjectRegions. If it's a valid reinterpret_cast (i.e. if the
353 // derived class has a zero offset from the base class), then it's safe
354 // to strip the cast; if it's invalid, -Wreinterpret-base-class should
355 // catch it. In the interest of performance, the analyzer will silently
356 // do the wrong thing in the invalid case (because offsets for subregions
358 const MemRegion *Uncasted = MR->StripCasts(/*IncludeBaseCasts=*/false);
359 if (Uncasted == MR) {
360 // We reached the bottom of the hierarchy and did not find the derived
361 // class. We we must be casting the base to derived, so the cast should
369 // We failed if the region we ended up with has perfect type info.
370 Failed = isa<TypedValueRegion>(MR);
375 /// CastRetrievedVal - Used by subclasses of StoreManager to implement
376 /// implicit casts that arise from loads from regions that are reinterpreted
377 /// as another region.
378 SVal StoreManager::CastRetrievedVal(SVal V, const TypedValueRegion *R,
379 QualType castTy, bool performTestOnly) {
381 if (castTy.isNull() || V.isUnknownOrUndef())
384 ASTContext &Ctx = svalBuilder.getContext();
386 if (performTestOnly) {
387 // Automatically translate references to pointers.
388 QualType T = R->getValueType();
389 if (const ReferenceType *RT = T->getAs<ReferenceType>())
390 T = Ctx.getPointerType(RT->getPointeeType());
392 assert(svalBuilder.getContext().hasSameUnqualifiedType(castTy, T));
396 return svalBuilder.dispatchCast(V, castTy);
399 SVal StoreManager::getLValueFieldOrIvar(const Decl *D, SVal Base) {
400 if (Base.isUnknownOrUndef())
403 Loc BaseL = Base.castAs<Loc>();
404 const MemRegion* BaseR = 0;
406 switch (BaseL.getSubKind()) {
407 case loc::MemRegionKind:
408 BaseR = BaseL.castAs<loc::MemRegionVal>().getRegion();
411 case loc::GotoLabelKind:
412 // These are anormal cases. Flag an undefined value.
413 return UndefinedVal();
415 case loc::ConcreteIntKind:
416 // While these seem funny, this can happen through casts.
417 // FIXME: What we should return is the field offset. For example,
418 // add the field offset to the integer value. That way funny things
419 // like this work properly: &(((struct foo *) 0xa)->f)
423 llvm_unreachable("Unhandled Base.");
426 // NOTE: We must have this check first because ObjCIvarDecl is a subclass
428 if (const ObjCIvarDecl *ID = dyn_cast<ObjCIvarDecl>(D))
429 return loc::MemRegionVal(MRMgr.getObjCIvarRegion(ID, BaseR));
431 return loc::MemRegionVal(MRMgr.getFieldRegion(cast<FieldDecl>(D), BaseR));
434 SVal StoreManager::getLValueIvar(const ObjCIvarDecl *decl, SVal base) {
435 return getLValueFieldOrIvar(decl, base);
438 SVal StoreManager::getLValueElement(QualType elementType, NonLoc Offset,
441 // If the base is an unknown or undefined value, just return it back.
442 // FIXME: For absolute pointer addresses, we just return that value back as
443 // well, although in reality we should return the offset added to that
445 if (Base.isUnknownOrUndef() || Base.getAs<loc::ConcreteInt>())
448 const MemRegion* BaseRegion = Base.castAs<loc::MemRegionVal>().getRegion();
450 // Pointer of any type can be cast and used as array base.
451 const ElementRegion *ElemR = dyn_cast<ElementRegion>(BaseRegion);
453 // Convert the offset to the appropriate size and signedness.
454 Offset = svalBuilder.convertToArrayIndex(Offset).castAs<NonLoc>();
458 // If the base region is not an ElementRegion, create one.
459 // This can happen in the following example:
461 // char *p = __builtin_alloc(10);
464 // Observe that 'p' binds to an AllocaRegion.
466 return loc::MemRegionVal(MRMgr.getElementRegion(elementType, Offset,
470 SVal BaseIdx = ElemR->getIndex();
472 if (!BaseIdx.getAs<nonloc::ConcreteInt>())
475 const llvm::APSInt &BaseIdxI =
476 BaseIdx.castAs<nonloc::ConcreteInt>().getValue();
478 // Only allow non-integer offsets if the base region has no offset itself.
479 // FIXME: This is a somewhat arbitrary restriction. We should be using
480 // SValBuilder here to add the two offsets without checking their types.
481 if (!Offset.getAs<nonloc::ConcreteInt>()) {
482 if (isa<ElementRegion>(BaseRegion->StripCasts()))
485 return loc::MemRegionVal(MRMgr.getElementRegion(elementType, Offset,
486 ElemR->getSuperRegion(),
490 const llvm::APSInt& OffI = Offset.castAs<nonloc::ConcreteInt>().getValue();
491 assert(BaseIdxI.isSigned());
493 // Compute the new index.
494 nonloc::ConcreteInt NewIdx(svalBuilder.getBasicValueFactory().getValue(BaseIdxI +
497 // Construct the new ElementRegion.
498 const MemRegion *ArrayR = ElemR->getSuperRegion();
499 return loc::MemRegionVal(MRMgr.getElementRegion(elementType, NewIdx, ArrayR,
503 StoreManager::BindingsHandler::~BindingsHandler() {}
505 bool StoreManager::FindUniqueBinding::HandleBinding(StoreManager& SMgr,
509 SymbolRef SymV = val.getAsLocSymbol();
510 if (!SymV || SymV != Sym)