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:
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 
51   iterator begin() const { return L.begin(); }
52   iterator end() const { return L.end(); }
53 
54   QualType getType() const { return T; }
55 
56   static void Profile(llvm::FoldingSetNodeID& ID, QualType T,
57                       llvm::ImmutableList<SVal> L);
58 
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:
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.
74   const void *getStore() const { return store.getStore(); }
75 
76   LLVM_ATTRIBUTE_RETURNS_NONNULL
77   const TypedValueRegion *getRegion() const { return region; }
78 
79   static void Profile(llvm::FoldingSetNodeID& ID,
80                       const StoreRef &store,
81                       const TypedValueRegion *region);
82 
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:
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 
97   iterator begin() const { return L.begin(); }
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 
103   void Profile(llvm::FoldingSetNodeID &ID) { Profile(ID, D, L); }
104 
105   /// It might return null.
106   const NamedDecl *getDeclaratorDecl() const { return D; }
107 
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:
135   BasicValueFactory(ASTContext &ctx, llvm::BumpPtrAllocator &Alloc)
136       : Ctx(ctx), BPAlloc(Alloc), SValListFactory(Alloc),
137         CXXBaseListFactory(Alloc) {}
138 
139   ~BasicValueFactory();
140 
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.
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     assert(T->isIntegralOrEnumerationType() || Loc::isLocType(T));
156     return APSIntType(Ctx.getIntWidth(T),
157                       !T->isSignedIntegerOrEnumerationType());
158   }
159 
160   /// Convert - Create a new persistent APSInt with the same value as 'From'
161   ///  but with the bitwidth and signedness of 'To'.
162   const llvm::APSInt &Convert(const llvm::APSInt& To,
163                               const llvm::APSInt& From) {
164     APSIntType TargetType(To);
165     if (TargetType == APSIntType(From))
166       return From;
167 
168     return getValue(TargetType.convert(From));
169   }
170 
171   const llvm::APSInt &Convert(QualType T, const llvm::APSInt &From) {
172     APSIntType TargetType = getAPSIntType(T);
173     return Convert(TargetType, From);
174   }
175 
176   const llvm::APSInt &Convert(APSIntType TargetType, const llvm::APSInt &From) {
177     if (TargetType == APSIntType(From))
178       return From;
179 
180     return getValue(TargetType.convert(From));
181   }
182 
183   const llvm::APSInt &getIntValue(uint64_t X, bool isUnsigned) {
184     QualType T = isUnsigned ? Ctx.UnsignedIntTy : Ctx.IntTy;
185     return getValue(X, T);
186   }
187 
188   const llvm::APSInt &getMaxValue(const llvm::APSInt &v) {
189     return getValue(APSIntType(v).getMaxValue());
190   }
191 
192   const llvm::APSInt &getMinValue(const llvm::APSInt &v) {
193     return getValue(APSIntType(v).getMinValue());
194   }
195 
196   const llvm::APSInt &getMaxValue(QualType T) {
197     return getMaxValue(getAPSIntType(T));
198   }
199 
200   const llvm::APSInt &getMinValue(QualType T) {
201     return getMinValue(getAPSIntType(T));
202   }
203 
204   const llvm::APSInt &getMaxValue(APSIntType T) {
205     return getValue(T.getMaxValue());
206   }
207 
208   const llvm::APSInt &getMinValue(APSIntType T) {
209     return getValue(T.getMinValue());
210   }
211 
212   const llvm::APSInt &Add1(const llvm::APSInt &V) {
213     llvm::APSInt X = V;
214     ++X;
215     return getValue(X);
216   }
217 
218   const llvm::APSInt &Sub1(const llvm::APSInt &V) {
219     llvm::APSInt X = V;
220     --X;
221     return getValue(X);
222   }
223 
224   const llvm::APSInt &getZeroWithTypeSize(QualType T) {
225     assert(T->isScalarType());
226     return getValue(0, Ctx.getTypeSize(T), true);
227   }
228 
229   const llvm::APSInt &getTruthValue(bool b, QualType T) {
230     return getValue(b ? 1 : 0, Ctx.getIntWidth(T),
231                     T->isUnsignedIntegerOrEnumerationType());
232   }
233 
234   const llvm::APSInt &getTruthValue(bool b) {
235     return getTruthValue(b, Ctx.getLogicalOperationType());
236   }
237 
238   const CompoundValData *getCompoundValData(QualType T,
239                                             llvm::ImmutableList<SVal> Vals);
240 
241   const LazyCompoundValData *getLazyCompoundValData(const StoreRef &store,
242                                             const TypedValueRegion *region);
243 
244   const PointerToMemberData *
245   getPointerToMemberData(const NamedDecl *ND,
246                          llvm::ImmutableList<const CXXBaseSpecifier *> L);
247 
248   llvm::ImmutableList<SVal> getEmptySValList() {
249     return SValListFactory.getEmptyList();
250   }
251 
252   llvm::ImmutableList<SVal> prependSVal(SVal X, llvm::ImmutableList<SVal> L) {
253     return SValListFactory.add(X, L);
254   }
255 
256   llvm::ImmutableList<const CXXBaseSpecifier *> getEmptyCXXBaseList() {
257     return CXXBaseListFactory.getEmptyList();
258   }
259 
260   llvm::ImmutableList<const CXXBaseSpecifier *> prependCXXBase(
261       const CXXBaseSpecifier *CBS,
262       llvm::ImmutableList<const CXXBaseSpecifier *> L) {
263     return CXXBaseListFactory.add(CBS, L);
264   }
265 
266   const PointerToMemberData *
267   accumCXXBase(llvm::iterator_range<CastExpr::path_const_iterator> PathRange,
268                const nonloc::PointerToMember &PTM, const clang::CastKind &kind);
269 
270   const llvm::APSInt* evalAPSInt(BinaryOperator::Opcode Op,
271                                      const llvm::APSInt& V1,
272                                      const llvm::APSInt& V2);
273 
274   const std::pair<SVal, uintptr_t>&
275   getPersistentSValWithData(const SVal& V, uintptr_t Data);
276 
277   const std::pair<SVal, SVal>&
278   getPersistentSValPair(const SVal& V1, const SVal& V2);
279 
280   const SVal* getPersistentSVal(SVal X);
281 };
282 
283 } // namespace ento
284 
285 } // namespace clang
286 
287 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_BASICVALUEFACTORY_H
288