1//===- Store.h - Interface for maps from Locations to Values ----*- 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 defined the types Store and StoreManager.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H
14#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H
15
16#include "clang/AST/Type.h"
17#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
18#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
20#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
21#include "clang/StaticAnalyzer/Core/PathSensitive/StoreRef.h"
22#include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h"
23#include "clang/Basic/LLVM.h"
24#include "llvm/ADT/ArrayRef.h"
25#include "llvm/ADT/DenseSet.h"
26#include "llvm/ADT/Optional.h"
27#include "llvm/ADT/SmallVector.h"
28#include <cassert>
29#include <cstdint>
30#include <memory>
31
32namespace clang {
33
34class ASTContext;
35class CastExpr;
36class CompoundLiteralExpr;
37class CXXBasePath;
38class Decl;
39class Expr;
40class LocationContext;
41class ObjCIvarDecl;
42class StackFrameContext;
43
44namespace ento {
45
46class CallEvent;
47class ProgramStateManager;
48class ScanReachableSymbols;
49class SymbolReaper;
50
51using InvalidatedSymbols = llvm::DenseSet<SymbolRef>;
52
53class StoreManager {
54protected:
55 SValBuilder &svalBuilder;
56 ProgramStateManager &StateMgr;
57
58 /// MRMgr - Manages region objects associated with this StoreManager.
59 MemRegionManager &MRMgr;
60 ASTContext &Ctx;
61
62 StoreManager(ProgramStateManager &stateMgr);
63
64public:
65 virtual ~StoreManager() = default;
66
67 /// Return the value bound to specified location in a given state.
68 /// \param[in] store The store in which to make the lookup.
69 /// \param[in] loc The symbolic memory location.
70 /// \param[in] T An optional type that provides a hint indicating the
71 /// expected type of the returned value. This is used if the value is
72 /// lazily computed.
73 /// \return The value bound to the location \c loc.
74 virtual SVal getBinding(Store store, Loc loc, QualType T = QualType()) = 0;
75
76 /// Return the default value bound to a region in a given store. The default
77 /// binding is the value of sub-regions that were not initialized separately
78 /// from their base region. For example, if the structure is zero-initialized
79 /// upon construction, this method retrieves the concrete zero value, even if
80 /// some or all fields were later overwritten manually. Default binding may be
81 /// an unknown, undefined, concrete, or symbolic value.
82 /// \param[in] store The store in which to make the lookup.
83 /// \param[in] R The region to find the default binding for.
84 /// \return The default value bound to the region in the store, if a default
85 /// binding exists.
86 virtual Optional<SVal> getDefaultBinding(Store store, const MemRegion *R) = 0;
87
88 /// Return the default value bound to a LazyCompoundVal. The default binding
89 /// is used to represent the value of any fields or elements within the
90 /// structure represented by the LazyCompoundVal which were not initialized
91 /// explicitly separately from the whole structure. Default binding may be an
92 /// unknown, undefined, concrete, or symbolic value.
93 /// \param[in] lcv The lazy compound value.
94 /// \return The default value bound to the LazyCompoundVal \c lcv, if a
95 /// default binding exists.
96 Optional<SVal> getDefaultBinding(nonloc::LazyCompoundVal lcv) {
97 return getDefaultBinding(lcv.getStore(), lcv.getRegion());
98 }
99
100 /// Return a store with the specified value bound to the given location.
101 /// \param[in] store The store in which to make the binding.
102 /// \param[in] loc The symbolic memory location.
103 /// \param[in] val The value to bind to location \c loc.
104 /// \return A StoreRef object that contains the same
105 /// bindings as \c store with the addition of having the value specified
106 /// by \c val bound to the location given for \c loc.
107 virtual StoreRef Bind(Store store, Loc loc, SVal val) = 0;
108
109 /// Return a store with the specified value bound to all sub-regions of the
110 /// region. The region must not have previous bindings. If you need to
111 /// invalidate existing bindings, consider invalidateRegions().
112 virtual StoreRef BindDefaultInitial(Store store, const MemRegion *R,
113 SVal V) = 0;
114
115 /// Return a store with in which all values within the given region are
116 /// reset to zero. This method is allowed to overwrite previous bindings.
117 virtual StoreRef BindDefaultZero(Store store, const MemRegion *R) = 0;
118
119 /// Create a new store with the specified binding removed.
120 /// \param ST the original store, that is the basis for the new store.
121 /// \param L the location whose binding should be removed.
122 virtual StoreRef killBinding(Store ST, Loc L) = 0;
123
124 /// getInitialStore - Returns the initial "empty" store representing the
125 /// value bindings upon entry to an analyzed function.
126 virtual StoreRef getInitialStore(const LocationContext *InitLoc) = 0;
127
128 /// getRegionManager - Returns the internal RegionManager object that is
129 /// used to query and manipulate MemRegion objects.
130 MemRegionManager& getRegionManager() { return MRMgr; }
131
132 SValBuilder& getSValBuilder() { return svalBuilder; }
133
134 virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) {
135 return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC));
136 }
137
138 Loc getLValueCompoundLiteral(const CompoundLiteralExpr *CL,
139 const LocationContext *LC) {
140 return loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC));
141 }
142
143 virtual SVal getLValueIvar(const ObjCIvarDecl *decl, SVal base);
144
145 virtual SVal getLValueField(const FieldDecl *D, SVal Base) {
146 return getLValueFieldOrIvar(D, Base);
147 }
148
149 virtual SVal getLValueElement(QualType elementType, NonLoc offset, SVal Base);
150
151 /// ArrayToPointer - Used by ExprEngine::VistCast to handle implicit
152 /// conversions between arrays and pointers.
153 virtual SVal ArrayToPointer(Loc Array, QualType ElementTy) = 0;
154
155 /// Evaluates a chain of derived-to-base casts through the path specified in
156 /// \p Cast.
157 SVal evalDerivedToBase(SVal Derived, const CastExpr *Cast);
158
159 /// Evaluates a chain of derived-to-base casts through the specified path.
160 SVal evalDerivedToBase(SVal Derived, const CXXBasePath &CastPath);
161
162 /// Evaluates a derived-to-base cast through a single level of derivation.
163 SVal evalDerivedToBase(SVal Derived, QualType DerivedPtrType,
164 bool IsVirtual);
165
166 /// Attempts to do a down cast. Used to model BaseToDerived and C++
167 /// dynamic_cast.
168 /// The callback may result in the following 3 scenarios:
169 /// - Successful cast (ex: derived is subclass of base).
170 /// - Failed cast (ex: derived is definitely not a subclass of base).
171 /// The distinction of this case from the next one is necessary to model
172 /// dynamic_cast.
173 /// - We don't know (base is a symbolic region and we don't have
174 /// enough info to determine if the cast will succeed at run time).
175 /// The function returns an SVal representing the derived class; it's
176 /// valid only if Failed flag is set to false.
177 SVal attemptDownCast(SVal Base, QualType DerivedPtrType, bool &Failed);
178
179 const ElementRegion *GetElementZeroRegion(const SubRegion *R, QualType T);
180
181 /// castRegion - Used by ExprEngine::VisitCast to handle casts from
182 /// a MemRegion* to a specific location type. 'R' is the region being
183 /// casted and 'CastToTy' the result type of the cast.
184 const MemRegion *castRegion(const MemRegion *region, QualType CastToTy);
185
186 virtual StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
187 SymbolReaper &SymReaper) = 0;
188
189 virtual bool includedInBindings(Store store,
190 const MemRegion *region) const = 0;
191
192 /// If the StoreManager supports it, increment the reference count of
193 /// the specified Store object.
194 virtual void incrementReferenceCount(Store store) {}
195
196 /// If the StoreManager supports it, decrement the reference count of
197 /// the specified Store object. If the reference count hits 0, the memory
198 /// associated with the object is recycled.
199 virtual void decrementReferenceCount(Store store) {}
200
201 using InvalidatedRegions = SmallVector<const MemRegion *, 8>;
202
203 /// invalidateRegions - Clears out the specified regions from the store,
204 /// marking their values as unknown. Depending on the store, this may also
205 /// invalidate additional regions that may have changed based on accessing
206 /// the given regions. Optionally, invalidates non-static globals as well.
207 /// \param[in] store The initial store
208 /// \param[in] Values The values to invalidate.
209 /// \param[in] E The current statement being evaluated. Used to conjure
210 /// symbols to mark the values of invalidated regions.
211 /// \param[in] Count The current block count. Used to conjure
212 /// symbols to mark the values of invalidated regions.
213 /// \param[in] Call The call expression which will be used to determine which
214 /// globals should get invalidated.
215 /// \param[in,out] IS A set to fill with any symbols that are no longer
216 /// accessible. Pass \c NULL if this information will not be used.
217 /// \param[in] ITraits Information about invalidation for a particular
218 /// region/symbol.
219 /// \param[in,out] InvalidatedTopLevel A vector to fill with regions
220 //// explicitly being invalidated. Pass \c NULL if this
221 /// information will not be used.
222 /// \param[in,out] Invalidated A vector to fill with any regions being
223 /// invalidated. This should include any regions explicitly invalidated
224 /// even if they do not currently have bindings. Pass \c NULL if this
225 /// information will not be used.
226 virtual StoreRef invalidateRegions(Store store,
227 ArrayRef<SVal> Values,
228 const Expr *E, unsigned Count,
229 const LocationContext *LCtx,
230 const CallEvent *Call,
231 InvalidatedSymbols &IS,
232 RegionAndSymbolInvalidationTraits &ITraits,
233 InvalidatedRegions *InvalidatedTopLevel,
234 InvalidatedRegions *Invalidated) = 0;
235
236 /// enterStackFrame - Let the StoreManager to do something when execution
237 /// engine is about to execute into a callee.
238 StoreRef enterStackFrame(Store store,
239 const CallEvent &Call,
240 const StackFrameContext *CalleeCtx);
241
242 /// Finds the transitive closure of symbols within the given region.
243 ///
244 /// Returns false if the visitor aborted the scan.
245 virtual bool scanReachableSymbols(Store S, const MemRegion *R,
246 ScanReachableSymbols &Visitor) = 0;
247
248 virtual void printJson(raw_ostream &Out, Store S, const char *NL,
249 unsigned int Space, bool IsDot) const = 0;
250
251 class BindingsHandler {
252 public:
253 virtual ~BindingsHandler();
254
255 /// \return whether the iteration should continue.
256 virtual bool HandleBinding(StoreManager& SMgr, Store store,
257 const MemRegion *region, SVal val) = 0;
258 };
259
260 class FindUniqueBinding : public BindingsHandler {
261 SymbolRef Sym;
262 const MemRegion* Binding = nullptr;
263 bool First = true;
264
265 public:
266 FindUniqueBinding(SymbolRef sym) : Sym(sym) {}
267
268 explicit operator bool() { return First && Binding; }
269
270 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
271 SVal val) override;
272 const MemRegion *getRegion() { return Binding; }
273 };
274
275 /// iterBindings - Iterate over the bindings in the Store.
276 virtual void iterBindings(Store store, BindingsHandler& f) = 0;
277
278protected:
279 const ElementRegion *MakeElementRegion(const SubRegion *baseRegion,
280 QualType pointeeTy,
281 uint64_t index = 0);
282
283private:
284 SVal getLValueFieldOrIvar(const Decl *decl, SVal base);
285};
286
287inline StoreRef::StoreRef(Store store, StoreManager & smgr)
288 : store(store), mgr(smgr) {
289 if (store)
290 mgr.incrementReferenceCount(store);
291}
292
293inline StoreRef::StoreRef(const StoreRef &sr)
294 : store(sr.store), mgr(sr.mgr)
295{
296 if (store)
297 mgr.incrementReferenceCount(store);
298}
299
300inline StoreRef::~StoreRef() {
301 if (store)
302 mgr.decrementReferenceCount(store);
303}
304
305inline StoreRef &StoreRef::operator=(StoreRef const &newStore) {
306 assert(&newStore.mgr == &mgr);
307 if (store != newStore.store) {
308 mgr.incrementReferenceCount(newStore.store);
309 mgr.decrementReferenceCount(store);
310 store = newStore.getStore();
311 }
312 return *this;
313}
314
315// FIXME: Do we need to pass ProgramStateManager anymore?
316std::unique_ptr<StoreManager>
317CreateRegionStoreManager(ProgramStateManager &StMgr);
318std::unique_ptr<StoreManager>
319CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr);
320
321} // namespace ento
322
323} // namespace clang
324
325#endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H
326