| //== Store.cpp - Interface for maps from Locations to 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 defined the types Store and StoreManager. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Checker/PathSensitive/Store.h" |
| #include "clang/Checker/PathSensitive/GRState.h" |
| #include "clang/AST/CharUnits.h" |
| |
| using namespace clang; |
| |
| StoreManager::StoreManager(GRStateManager &stateMgr) |
| : ValMgr(stateMgr.getValueManager()), StateMgr(stateMgr), |
| MRMgr(ValMgr.getRegionManager()), Ctx(stateMgr.getContext()) {} |
| |
| const MemRegion *StoreManager::MakeElementRegion(const MemRegion *Base, |
| QualType EleTy, uint64_t index) { |
| SVal idx = ValMgr.makeArrayIndex(index); |
| return MRMgr.getElementRegion(EleTy, idx, Base, ValMgr.getContext()); |
| } |
| |
| // FIXME: Merge with the implementation of the same method in MemRegion.cpp |
| static bool IsCompleteType(ASTContext &Ctx, QualType Ty) { |
| if (const RecordType *RT = Ty->getAs<RecordType>()) { |
| const RecordDecl *D = RT->getDecl(); |
| if (!D->getDefinition()) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| const ElementRegion *StoreManager::GetElementZeroRegion(const MemRegion *R, |
| QualType T) { |
| SVal idx = ValMgr.makeZeroArrayIndex(); |
| assert(!T.isNull()); |
| return MRMgr.getElementRegion(T, idx, R, Ctx); |
| } |
| |
| const MemRegion *StoreManager::CastRegion(const MemRegion *R, QualType CastToTy) { |
| |
| ASTContext& Ctx = StateMgr.getContext(); |
| |
| // Handle casts to Objective-C objects. |
| if (CastToTy->isObjCObjectPointerType()) |
| return R->StripCasts(); |
| |
| if (CastToTy->isBlockPointerType()) { |
| // FIXME: We may need different solutions, depending on the symbol |
| // involved. Blocks can be casted to/from 'id', as they can be treated |
| // as Objective-C objects. This could possibly be handled by enhancing |
| // our reasoning of downcasts of symbolic objects. |
| if (isa<CodeTextRegion>(R) || isa<SymbolicRegion>(R)) |
| return R; |
| |
| // We don't know what to make of it. Return a NULL region, which |
| // will be interpretted as UnknownVal. |
| return NULL; |
| } |
| |
| // Now assume we are casting from pointer to pointer. Other cases should |
| // already be handled. |
| QualType PointeeTy = CastToTy->getAs<PointerType>()->getPointeeType(); |
| QualType CanonPointeeTy = Ctx.getCanonicalType(PointeeTy); |
| |
| // Handle casts to void*. We just pass the region through. |
| if (CanonPointeeTy.getLocalUnqualifiedType() == Ctx.VoidTy) |
| return R; |
| |
| // Handle casts from compatible types. |
| if (R->isBoundable()) |
| if (const TypedRegion *TR = dyn_cast<TypedRegion>(R)) { |
| QualType ObjTy = Ctx.getCanonicalType(TR->getValueType(Ctx)); |
| if (CanonPointeeTy == ObjTy) |
| return R; |
| } |
| |
| // Process region cast according to the kind of the region being cast. |
| switch (R->getKind()) { |
| case MemRegion::CXXThisRegionKind: |
| case MemRegion::GenericMemSpaceRegionKind: |
| case MemRegion::StackLocalsSpaceRegionKind: |
| case MemRegion::StackArgumentsSpaceRegionKind: |
| case MemRegion::HeapSpaceRegionKind: |
| case MemRegion::UnknownSpaceRegionKind: |
| case MemRegion::NonStaticGlobalSpaceRegionKind: |
| case MemRegion::StaticGlobalSpaceRegionKind: { |
| assert(0 && "Invalid region cast"); |
| break; |
| } |
| |
| case MemRegion::FunctionTextRegionKind: |
| case MemRegion::BlockTextRegionKind: |
| case MemRegion::BlockDataRegionKind: { |
| // CodeTextRegion should be cast to only a function or block pointer type, |
| // although they can in practice be casted to anything, e.g, void*, char*, |
| // etc. |
| // Just return the region. |
| return R; |
| } |
| |
| case MemRegion::StringRegionKind: |
| // FIXME: Need to handle arbitrary downcasts. |
| case MemRegion::SymbolicRegionKind: |
| case MemRegion::AllocaRegionKind: |
| case MemRegion::CompoundLiteralRegionKind: |
| case MemRegion::FieldRegionKind: |
| case MemRegion::ObjCIvarRegionKind: |
| case MemRegion::VarRegionKind: |
| case MemRegion::CXXObjectRegionKind: |
| return MakeElementRegion(R, PointeeTy); |
| |
| case MemRegion::ElementRegionKind: { |
| // If we are casting from an ElementRegion to another type, the |
| // algorithm is as follows: |
| // |
| // (1) Compute the "raw offset" of the ElementRegion from the |
| // base region. This is done by calling 'getAsRawOffset()'. |
| // |
| // (2a) If we get a 'RegionRawOffset' after calling |
| // 'getAsRawOffset()', determine if the absolute offset |
| // can be exactly divided into chunks of the size of the |
| // casted-pointee type. If so, create a new ElementRegion with |
| // the pointee-cast type as the new ElementType and the index |
| // being the offset divded by the chunk size. If not, create |
| // a new ElementRegion at offset 0 off the raw offset region. |
| // |
| // (2b) If we don't a get a 'RegionRawOffset' after calling |
| // 'getAsRawOffset()', it means that we are at offset 0. |
| // |
| // FIXME: Handle symbolic raw offsets. |
| |
| const ElementRegion *elementR = cast<ElementRegion>(R); |
| const RegionRawOffset &rawOff = elementR->getAsRawOffset(); |
| const MemRegion *baseR = rawOff.getRegion(); |
| |
| // If we cannot compute a raw offset, throw up our hands and return |
| // a NULL MemRegion*. |
| if (!baseR) |
| return NULL; |
| |
| CharUnits off = CharUnits::fromQuantity(rawOff.getByteOffset()); |
| |
| if (off.isZero()) { |
| // Edge case: we are at 0 bytes off the beginning of baseR. We |
| // check to see if type we are casting to is the same as the base |
| // region. If so, just return the base region. |
| if (const TypedRegion *TR = dyn_cast<TypedRegion>(baseR)) { |
| QualType ObjTy = Ctx.getCanonicalType(TR->getValueType(Ctx)); |
| QualType CanonPointeeTy = Ctx.getCanonicalType(PointeeTy); |
| if (CanonPointeeTy == ObjTy) |
| return baseR; |
| } |
| |
| // Otherwise, create a new ElementRegion at offset 0. |
| return MakeElementRegion(baseR, PointeeTy); |
| } |
| |
| // We have a non-zero offset from the base region. We want to determine |
| // if the offset can be evenly divided by sizeof(PointeeTy). If so, |
| // we create an ElementRegion whose index is that value. Otherwise, we |
| // create two ElementRegions, one that reflects a raw offset and the other |
| // that reflects the cast. |
| |
| // Compute the index for the new ElementRegion. |
| int64_t newIndex = 0; |
| const MemRegion *newSuperR = 0; |
| |
| // We can only compute sizeof(PointeeTy) if it is a complete type. |
| if (IsCompleteType(Ctx, PointeeTy)) { |
| // Compute the size in **bytes**. |
| CharUnits pointeeTySize = Ctx.getTypeSizeInChars(PointeeTy); |
| if (!pointeeTySize.isZero()) { |
| // Is the offset a multiple of the size? If so, we can layer the |
| // ElementRegion (with elementType == PointeeTy) directly on top of |
| // the base region. |
| if (off % pointeeTySize == 0) { |
| newIndex = off / pointeeTySize; |
| newSuperR = baseR; |
| } |
| } |
| } |
| |
| if (!newSuperR) { |
| // Create an intermediate ElementRegion to represent the raw byte. |
| // This will be the super region of the final ElementRegion. |
| newSuperR = MakeElementRegion(baseR, Ctx.CharTy, off.getQuantity()); |
| } |
| |
| return MakeElementRegion(newSuperR, PointeeTy, newIndex); |
| } |
| } |
| |
| assert(0 && "unreachable"); |
| return 0; |
| } |
| |
| |
| /// CastRetrievedVal - Used by subclasses of StoreManager to implement |
| /// implicit casts that arise from loads from regions that are reinterpreted |
| /// as another region. |
| SVal StoreManager::CastRetrievedVal(SVal V, const TypedRegion *R, |
| QualType castTy, bool performTestOnly) { |
| |
| if (castTy.isNull()) |
| return V; |
| |
| ASTContext &Ctx = ValMgr.getContext(); |
| |
| if (performTestOnly) { |
| // Automatically translate references to pointers. |
| QualType T = R->getValueType(Ctx); |
| if (const ReferenceType *RT = T->getAs<ReferenceType>()) |
| T = Ctx.getPointerType(RT->getPointeeType()); |
| |
| assert(ValMgr.getContext().hasSameUnqualifiedType(castTy, T)); |
| return V; |
| } |
| |
| if (const Loc *L = dyn_cast<Loc>(&V)) |
| return ValMgr.getSValuator().EvalCastL(*L, castTy); |
| else if (const NonLoc *NL = dyn_cast<NonLoc>(&V)) |
| return ValMgr.getSValuator().EvalCastNL(*NL, castTy); |
| |
| return V; |
| } |
| |
| SVal StoreManager::getLValueFieldOrIvar(const Decl* D, SVal Base) { |
| if (Base.isUnknownOrUndef()) |
| return Base; |
| |
| Loc BaseL = cast<Loc>(Base); |
| const MemRegion* BaseR = 0; |
| |
| switch (BaseL.getSubKind()) { |
| case loc::MemRegionKind: |
| BaseR = cast<loc::MemRegionVal>(BaseL).getRegion(); |
| break; |
| |
| case loc::GotoLabelKind: |
| // These are anormal cases. Flag an undefined value. |
| return UndefinedVal(); |
| |
| case loc::ConcreteIntKind: |
| // While these seem funny, this can happen through casts. |
| // FIXME: What we should return is the field offset. For example, |
| // add the field offset to the integer value. That way funny things |
| // like this work properly: &(((struct foo *) 0xa)->f) |
| return Base; |
| |
| default: |
| assert(0 && "Unhandled Base."); |
| return Base; |
| } |
| |
| // NOTE: We must have this check first because ObjCIvarDecl is a subclass |
| // of FieldDecl. |
| if (const ObjCIvarDecl *ID = dyn_cast<ObjCIvarDecl>(D)) |
| return loc::MemRegionVal(MRMgr.getObjCIvarRegion(ID, BaseR)); |
| |
| return loc::MemRegionVal(MRMgr.getFieldRegion(cast<FieldDecl>(D), BaseR)); |
| } |
| |
| SVal StoreManager::getLValueElement(QualType elementType, SVal Offset, |
| SVal Base) { |
| |
| // If the base is an unknown or undefined value, just return it back. |
| // FIXME: For absolute pointer addresses, we just return that value back as |
| // well, although in reality we should return the offset added to that |
| // value. |
| if (Base.isUnknownOrUndef() || isa<loc::ConcreteInt>(Base)) |
| return Base; |
| |
| // Only handle integer offsets... for now. |
| if (!isa<nonloc::ConcreteInt>(Offset)) |
| return UnknownVal(); |
| |
| const MemRegion* BaseRegion = cast<loc::MemRegionVal>(Base).getRegion(); |
| |
| // Pointer of any type can be cast and used as array base. |
| const ElementRegion *ElemR = dyn_cast<ElementRegion>(BaseRegion); |
| |
| // Convert the offset to the appropriate size and signedness. |
| Offset = ValMgr.convertToArrayIndex(Offset); |
| |
| if (!ElemR) { |
| // |
| // If the base region is not an ElementRegion, create one. |
| // This can happen in the following example: |
| // |
| // char *p = __builtin_alloc(10); |
| // p[1] = 8; |
| // |
| // Observe that 'p' binds to an AllocaRegion. |
| // |
| return loc::MemRegionVal(MRMgr.getElementRegion(elementType, Offset, |
| BaseRegion, Ctx)); |
| } |
| |
| SVal BaseIdx = ElemR->getIndex(); |
| |
| if (!isa<nonloc::ConcreteInt>(BaseIdx)) |
| return UnknownVal(); |
| |
| const llvm::APSInt& BaseIdxI = cast<nonloc::ConcreteInt>(BaseIdx).getValue(); |
| const llvm::APSInt& OffI = cast<nonloc::ConcreteInt>(Offset).getValue(); |
| assert(BaseIdxI.isSigned()); |
| |
| // Compute the new index. |
| SVal NewIdx = nonloc::ConcreteInt( |
| ValMgr.getBasicValueFactory().getValue(BaseIdxI + OffI)); |
| |
| // Construct the new ElementRegion. |
| const MemRegion *ArrayR = ElemR->getSuperRegion(); |
| return loc::MemRegionVal(MRMgr.getElementRegion(elementType, NewIdx, ArrayR, |
| Ctx)); |
| } |