1 //==- BasicValueFactory.h - Basic values for Path Sens analysis --*- C++ -*-==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file defines BasicValueFactory, a class that manages the lifetime
10 //  of APSInt objects and symbolic constraints used by ExprEngine
11 //  and related classes.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_BASICVALUEFACTORY_H
16 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_BASICVALUEFACTORY_H
17 
18 #include "clang/AST/ASTContext.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/Type.h"
21 #include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
22 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
23 #include "clang/StaticAnalyzer/Core/PathSensitive/StoreRef.h"
24 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
25 #include "llvm/ADT/APSInt.h"
26 #include "llvm/ADT/FoldingSet.h"
27 #include "llvm/ADT/ImmutableList.h"
28 #include "llvm/ADT/iterator_range.h"
29 #include "llvm/Support/Allocator.h"
30 #include <cassert>
31 #include <cstdint>
32 #include <utility>
33 
34 namespace clang {
35 
36 class CXXBaseSpecifier;
37 
38 namespace ento {
39 
40 class CompoundValData : public llvm::FoldingSetNode {
41   QualType T;
42   llvm::ImmutableList<SVal> L;
43 
44 public:
CompoundValData(QualType t,llvm::ImmutableList<SVal> l)45   CompoundValData(QualType t, llvm::ImmutableList<SVal> l) : T(t), L(l) {
46     assert(NonLoc::isCompoundType(t));
47   }
48 
49   using iterator = llvm::ImmutableList<SVal>::iterator;
50 
begin()51   iterator begin() const { return L.begin(); }
end()52   iterator end() const { return L.end(); }
53 
getType()54   QualType getType() const { return T; }
55 
56   static void Profile(llvm::FoldingSetNodeID& ID, QualType T,
57                       llvm::ImmutableList<SVal> L);
58 
Profile(llvm::FoldingSetNodeID & ID)59   void Profile(llvm::FoldingSetNodeID& ID) { Profile(ID, T, L); }
60 };
61 
62 class LazyCompoundValData : public llvm::FoldingSetNode {
63   StoreRef store;
64   const TypedValueRegion *region;
65 
66 public:
LazyCompoundValData(const StoreRef & st,const TypedValueRegion * r)67   LazyCompoundValData(const StoreRef &st, const TypedValueRegion *r)
68       : store(st), region(r) {
69     assert(r);
70     assert(NonLoc::isCompoundType(r->getValueType()));
71   }
72 
73   /// It might return null.
getStore()74   const void *getStore() const { return store.getStore(); }
75 
76   LLVM_ATTRIBUTE_RETURNS_NONNULL
getRegion()77   const TypedValueRegion *getRegion() const { return region; }
78 
79   static void Profile(llvm::FoldingSetNodeID& ID,
80                       const StoreRef &store,
81                       const TypedValueRegion *region);
82 
Profile(llvm::FoldingSetNodeID & ID)83   void Profile(llvm::FoldingSetNodeID& ID) { Profile(ID, store, region); }
84 };
85 
86 class PointerToMemberData : public llvm::FoldingSetNode {
87   const NamedDecl *D;
88   llvm::ImmutableList<const CXXBaseSpecifier *> L;
89 
90 public:
PointerToMemberData(const NamedDecl * D,llvm::ImmutableList<const CXXBaseSpecifier * > L)91   PointerToMemberData(const NamedDecl *D,
92                       llvm::ImmutableList<const CXXBaseSpecifier *> L)
93       : D(D), L(L) {}
94 
95   using iterator = llvm::ImmutableList<const CXXBaseSpecifier *>::iterator;
96 
begin()97   iterator begin() const { return L.begin(); }
end()98   iterator end() const { return L.end(); }
99 
100   static void Profile(llvm::FoldingSetNodeID &ID, const NamedDecl *D,
101                       llvm::ImmutableList<const CXXBaseSpecifier *> L);
102 
Profile(llvm::FoldingSetNodeID & ID)103   void Profile(llvm::FoldingSetNodeID &ID) { Profile(ID, D, L); }
104 
105   /// It might return null.
getDeclaratorDecl()106   const NamedDecl *getDeclaratorDecl() const { return D; }
107 
getCXXBaseList()108   llvm::ImmutableList<const CXXBaseSpecifier *> getCXXBaseList() const {
109     return L;
110   }
111 };
112 
113 class BasicValueFactory {
114   using APSIntSetTy =
115       llvm::FoldingSet<llvm::FoldingSetNodeWrapper<llvm::APSInt>>;
116 
117   ASTContext &Ctx;
118   llvm::BumpPtrAllocator& BPAlloc;
119 
120   APSIntSetTy APSIntSet;
121   void *PersistentSVals = nullptr;
122   void *PersistentSValPairs = nullptr;
123 
124   llvm::ImmutableList<SVal>::Factory SValListFactory;
125   llvm::ImmutableList<const CXXBaseSpecifier *>::Factory CXXBaseListFactory;
126   llvm::FoldingSet<CompoundValData>  CompoundValDataSet;
127   llvm::FoldingSet<LazyCompoundValData> LazyCompoundValDataSet;
128   llvm::FoldingSet<PointerToMemberData> PointerToMemberDataSet;
129 
130   // This is private because external clients should use the factory
131   // method that takes a QualType.
132   const llvm::APSInt& getValue(uint64_t X, unsigned BitWidth, bool isUnsigned);
133 
134 public:
BasicValueFactory(ASTContext & ctx,llvm::BumpPtrAllocator & Alloc)135   BasicValueFactory(ASTContext &ctx, llvm::BumpPtrAllocator &Alloc)
136       : Ctx(ctx), BPAlloc(Alloc), SValListFactory(Alloc),
137         CXXBaseListFactory(Alloc) {}
138 
139   ~BasicValueFactory();
140 
getContext()141   ASTContext &getContext() const { return Ctx; }
142 
143   const llvm::APSInt& getValue(const llvm::APSInt& X);
144   const llvm::APSInt& getValue(const llvm::APInt& X, bool isUnsigned);
145   const llvm::APSInt& getValue(uint64_t X, QualType T);
146 
147   /// Returns the type of the APSInt used to store values of the given QualType.
getAPSIntType(QualType T)148   APSIntType getAPSIntType(QualType T) const {
149     // For the purposes of the analysis and constraints, we treat atomics
150     // as their underlying types.
151     if (const AtomicType *AT = T->getAs<AtomicType>()) {
152       T = AT->getValueType();
153     }
154 
155     if (T->isIntegralOrEnumerationType() || Loc::isLocType(T)) {
156       return APSIntType(Ctx.getIntWidth(T),
157                         !T->isSignedIntegerOrEnumerationType());
158     } else {
159       // implicitly handle case of T->isFixedPointType()
160       return APSIntType(Ctx.getIntWidth(T), T->isUnsignedFixedPointType());
161     }
162 
163     llvm_unreachable("Unsupported type in getAPSIntType!");
164   }
165 
166   /// Convert - Create a new persistent APSInt with the same value as 'From'
167   ///  but with the bitwidth and signedness of 'To'.
Convert(const llvm::APSInt & To,const llvm::APSInt & From)168   const llvm::APSInt &Convert(const llvm::APSInt& To,
169                               const llvm::APSInt& From) {
170     APSIntType TargetType(To);
171     if (TargetType == APSIntType(From))
172       return From;
173 
174     return getValue(TargetType.convert(From));
175   }
176 
Convert(QualType T,const llvm::APSInt & From)177   const llvm::APSInt &Convert(QualType T, const llvm::APSInt &From) {
178     APSIntType TargetType = getAPSIntType(T);
179     return Convert(TargetType, From);
180   }
181 
Convert(APSIntType TargetType,const llvm::APSInt & From)182   const llvm::APSInt &Convert(APSIntType TargetType, const llvm::APSInt &From) {
183     if (TargetType == APSIntType(From))
184       return From;
185 
186     return getValue(TargetType.convert(From));
187   }
188 
getIntValue(uint64_t X,bool isUnsigned)189   const llvm::APSInt &getIntValue(uint64_t X, bool isUnsigned) {
190     QualType T = isUnsigned ? Ctx.UnsignedIntTy : Ctx.IntTy;
191     return getValue(X, T);
192   }
193 
getMaxValue(const llvm::APSInt & v)194   const llvm::APSInt &getMaxValue(const llvm::APSInt &v) {
195     return getValue(APSIntType(v).getMaxValue());
196   }
197 
getMinValue(const llvm::APSInt & v)198   const llvm::APSInt &getMinValue(const llvm::APSInt &v) {
199     return getValue(APSIntType(v).getMinValue());
200   }
201 
getMaxValue(QualType T)202   const llvm::APSInt &getMaxValue(QualType T) {
203     return getMaxValue(getAPSIntType(T));
204   }
205 
getMinValue(QualType T)206   const llvm::APSInt &getMinValue(QualType T) {
207     return getMinValue(getAPSIntType(T));
208   }
209 
getMaxValue(APSIntType T)210   const llvm::APSInt &getMaxValue(APSIntType T) {
211     return getValue(T.getMaxValue());
212   }
213 
getMinValue(APSIntType T)214   const llvm::APSInt &getMinValue(APSIntType T) {
215     return getValue(T.getMinValue());
216   }
217 
Add1(const llvm::APSInt & V)218   const llvm::APSInt &Add1(const llvm::APSInt &V) {
219     llvm::APSInt X = V;
220     ++X;
221     return getValue(X);
222   }
223 
Sub1(const llvm::APSInt & V)224   const llvm::APSInt &Sub1(const llvm::APSInt &V) {
225     llvm::APSInt X = V;
226     --X;
227     return getValue(X);
228   }
229 
getZeroWithTypeSize(QualType T)230   const llvm::APSInt &getZeroWithTypeSize(QualType T) {
231     assert(T->isScalarType());
232     return getValue(0, Ctx.getTypeSize(T), true);
233   }
234 
getTruthValue(bool b,QualType T)235   const llvm::APSInt &getTruthValue(bool b, QualType T) {
236     return getValue(b ? 1 : 0, Ctx.getIntWidth(T),
237                     T->isUnsignedIntegerOrEnumerationType());
238   }
239 
getTruthValue(bool b)240   const llvm::APSInt &getTruthValue(bool b) {
241     return getTruthValue(b, Ctx.getLogicalOperationType());
242   }
243 
244   const CompoundValData *getCompoundValData(QualType T,
245                                             llvm::ImmutableList<SVal> Vals);
246 
247   const LazyCompoundValData *getLazyCompoundValData(const StoreRef &store,
248                                             const TypedValueRegion *region);
249 
250   const PointerToMemberData *
251   getPointerToMemberData(const NamedDecl *ND,
252                          llvm::ImmutableList<const CXXBaseSpecifier *> L);
253 
getEmptySValList()254   llvm::ImmutableList<SVal> getEmptySValList() {
255     return SValListFactory.getEmptyList();
256   }
257 
prependSVal(SVal X,llvm::ImmutableList<SVal> L)258   llvm::ImmutableList<SVal> prependSVal(SVal X, llvm::ImmutableList<SVal> L) {
259     return SValListFactory.add(X, L);
260   }
261 
getEmptyCXXBaseList()262   llvm::ImmutableList<const CXXBaseSpecifier *> getEmptyCXXBaseList() {
263     return CXXBaseListFactory.getEmptyList();
264   }
265 
prependCXXBase(const CXXBaseSpecifier * CBS,llvm::ImmutableList<const CXXBaseSpecifier * > L)266   llvm::ImmutableList<const CXXBaseSpecifier *> prependCXXBase(
267       const CXXBaseSpecifier *CBS,
268       llvm::ImmutableList<const CXXBaseSpecifier *> L) {
269     return CXXBaseListFactory.add(CBS, L);
270   }
271 
272   const PointerToMemberData *
273   accumCXXBase(llvm::iterator_range<CastExpr::path_const_iterator> PathRange,
274                const nonloc::PointerToMember &PTM, const clang::CastKind &kind);
275 
276   const llvm::APSInt* evalAPSInt(BinaryOperator::Opcode Op,
277                                      const llvm::APSInt& V1,
278                                      const llvm::APSInt& V2);
279 
280   const std::pair<SVal, uintptr_t>&
281   getPersistentSValWithData(const SVal& V, uintptr_t Data);
282 
283   const std::pair<SVal, SVal>&
284   getPersistentSValPair(const SVal& V1, const SVal& V2);
285 
286   const SVal* getPersistentSVal(SVal X);
287 };
288 
289 } // namespace ento
290 
291 } // namespace clang
292 
293 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_BASICVALUEFACTORY_H
294