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 // FIXME: This should soon be eliminated altogether; clients should deal with
152 // region extents directly.
153 virtual DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
154 const MemRegion *region,
155 QualType EleTy) {
156 return UnknownVal();
157 }
158
159 /// ArrayToPointer - Used by ExprEngine::VistCast to handle implicit
160 /// conversions between arrays and pointers.
161 virtual SVal ArrayToPointer(Loc Array, QualType ElementTy) = 0;
162
163 /// Evaluates a chain of derived-to-base casts through the path specified in
164 /// \p Cast.
165 SVal evalDerivedToBase(SVal Derived, const CastExpr *Cast);
166
167 /// Evaluates a chain of derived-to-base casts through the specified path.
168 SVal evalDerivedToBase(SVal Derived, const CXXBasePath &CastPath);
169
170 /// Evaluates a derived-to-base cast through a single level of derivation.
171 SVal evalDerivedToBase(SVal Derived, QualType DerivedPtrType,
172 bool IsVirtual);
173
174 /// Attempts to do a down cast. Used to model BaseToDerived and C++
175 /// dynamic_cast.
176 /// The callback may result in the following 3 scenarios:
177 /// - Successful cast (ex: derived is subclass of base).
178 /// - Failed cast (ex: derived is definitely not a subclass of base).
179 /// The distinction of this case from the next one is necessary to model
180 /// dynamic_cast.
181 /// - We don't know (base is a symbolic region and we don't have
182 /// enough info to determine if the cast will succeed at run time).
183 /// The function returns an SVal representing the derived class; it's
184 /// valid only if Failed flag is set to false.
185 SVal attemptDownCast(SVal Base, QualType DerivedPtrType, bool &Failed);
186
187 const ElementRegion *GetElementZeroRegion(const SubRegion *R, QualType T);
188
189 /// castRegion - Used by ExprEngine::VisitCast to handle casts from
190 /// a MemRegion* to a specific location type. 'R' is the region being
191 /// casted and 'CastToTy' the result type of the cast.
192 const MemRegion *castRegion(const MemRegion *region, QualType CastToTy);
193
194 virtual StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
195 SymbolReaper &SymReaper) = 0;
196
197 virtual bool includedInBindings(Store store,
198 const MemRegion *region) const = 0;
199
200 /// If the StoreManager supports it, increment the reference count of
201 /// the specified Store object.
202 virtual void incrementReferenceCount(Store store) {}
203
204 /// If the StoreManager supports it, decrement the reference count of
205 /// the specified Store object. If the reference count hits 0, the memory
206 /// associated with the object is recycled.
207 virtual void decrementReferenceCount(Store store) {}
208
209 using InvalidatedRegions = SmallVector<const MemRegion *, 8>;
210
211 /// invalidateRegions - Clears out the specified regions from the store,
212 /// marking their values as unknown. Depending on the store, this may also
213 /// invalidate additional regions that may have changed based on accessing
214 /// the given regions. Optionally, invalidates non-static globals as well.
215 /// \param[in] store The initial store
216 /// \param[in] Values The values to invalidate.
217 /// \param[in] E The current statement being evaluated. Used to conjure
218 /// symbols to mark the values of invalidated regions.
219 /// \param[in] Count The current block count. Used to conjure
220 /// symbols to mark the values of invalidated regions.
221 /// \param[in] Call The call expression which will be used to determine which
222 /// globals should get invalidated.
223 /// \param[in,out] IS A set to fill with any symbols that are no longer
224 /// accessible. Pass \c NULL if this information will not be used.
225 /// \param[in] ITraits Information about invalidation for a particular
226 /// region/symbol.
227 /// \param[in,out] InvalidatedTopLevel A vector to fill with regions
228 //// explicitly being invalidated. Pass \c NULL if this
229 /// information will not be used.
230 /// \param[in,out] Invalidated A vector to fill with any regions being
231 /// invalidated. This should include any regions explicitly invalidated
232 /// even if they do not currently have bindings. Pass \c NULL if this
233 /// information will not be used.
234 virtual StoreRef invalidateRegions(Store store,
235 ArrayRef<SVal> Values,
236 const Expr *E, unsigned Count,
237 const LocationContext *LCtx,
238 const CallEvent *Call,
239 InvalidatedSymbols &IS,
240 RegionAndSymbolInvalidationTraits &ITraits,
241 InvalidatedRegions *InvalidatedTopLevel,
242 InvalidatedRegions *Invalidated) = 0;
243
244 /// enterStackFrame - Let the StoreManager to do something when execution
245 /// engine is about to execute into a callee.
246 StoreRef enterStackFrame(Store store,
247 const CallEvent &Call,
248 const StackFrameContext *CalleeCtx);
249
250 /// Finds the transitive closure of symbols within the given region.
251 ///
252 /// Returns false if the visitor aborted the scan.
253 virtual bool scanReachableSymbols(Store S, const MemRegion *R,
254 ScanReachableSymbols &Visitor) = 0;
255
256 virtual void print(Store store, raw_ostream &Out, const char* nl) = 0;
257
258 class BindingsHandler {
259 public:
260 virtual ~BindingsHandler();
261
262 /// \return whether the iteration should continue.
263 virtual bool HandleBinding(StoreManager& SMgr, Store store,
264 const MemRegion *region, SVal val) = 0;
265 };
266
267 class FindUniqueBinding : public BindingsHandler {
268 SymbolRef Sym;
269 const MemRegion* Binding = nullptr;
270 bool First = true;
271
272 public:
273 FindUniqueBinding(SymbolRef sym) : Sym(sym) {}
274
275 explicit operator bool() { return First && Binding; }
276
277 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
278 SVal val) override;
279 const MemRegion *getRegion() { return Binding; }
280 };
281
282 /// iterBindings - Iterate over the bindings in the Store.
283 virtual void iterBindings(Store store, BindingsHandler& f) = 0;
284
285protected:
286 const ElementRegion *MakeElementRegion(const SubRegion *baseRegion,
287 QualType pointeeTy,
288 uint64_t index = 0);
289
290 /// CastRetrievedVal - Used by subclasses of StoreManager to implement
291 /// implicit casts that arise from loads from regions that are reinterpreted
292 /// as another region.
293 SVal CastRetrievedVal(SVal val, const TypedValueRegion *region,
294 QualType castTy);
295
296private:
297 SVal getLValueFieldOrIvar(const Decl *decl, SVal base);
298};
299
300inline StoreRef::StoreRef(Store store, StoreManager & smgr)
301 : store(store), mgr(smgr) {
302 if (store)
303 mgr.incrementReferenceCount(store);
304}
305
306inline StoreRef::StoreRef(const StoreRef &sr)
307 : store(sr.store), mgr(sr.mgr)
308{
309 if (store)
310 mgr.incrementReferenceCount(store);
311}
312
313inline StoreRef::~StoreRef() {
314 if (store)
315 mgr.decrementReferenceCount(store);
316}
317
318inline StoreRef &StoreRef::operator=(StoreRef const &newStore) {
319 assert(&newStore.mgr == &mgr);
320 if (store != newStore.store) {
321 mgr.incrementReferenceCount(newStore.store);
322 mgr.decrementReferenceCount(store);
323 store = newStore.getStore();
324 }
325 return *this;
326}
327
328// FIXME: Do we need to pass ProgramStateManager anymore?
329std::unique_ptr<StoreManager>
330CreateRegionStoreManager(ProgramStateManager &StMgr);
331std::unique_ptr<StoreManager>
332CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr);
333
334} // namespace ento
335
336} // namespace clang
337
338#endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H
339