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Store.h
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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"
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 
32 namespace clang {
33 
34 class ASTContext;
35 class CastExpr;
36 class CompoundLiteralExpr;
37 class CXXBasePath;
38 class Decl;
39 class Expr;
40 class LocationContext;
41 class ObjCIvarDecl;
42 class StackFrameContext;
43 
44 namespace ento {
45 
46 class CallEvent;
47 class ProgramStateManager;
48 class ScanReachableSymbols;
49 class SymbolReaper;
50 
52 
53 class StoreManager {
54 protected:
57 
58  /// MRMgr - Manages region objects associated with this StoreManager.
61 
63 
64 public:
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.
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.
131 
133 
134  virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) {
135  return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC));
136  }
137 
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.
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 
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 
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,
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.
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 printJson(raw_ostream &Out, Store S, const char *NL,
257  unsigned int Space, bool IsDot) const = 0;
258 
260  public:
261  virtual ~BindingsHandler();
262 
263  /// \return whether the iteration should continue.
264  virtual bool HandleBinding(StoreManager& SMgr, Store store,
265  const MemRegion *region, SVal val) = 0;
266  };
267 
269  SymbolRef Sym;
270  const MemRegion* Binding = nullptr;
271  bool First = true;
272 
273  public:
274  FindUniqueBinding(SymbolRef sym) : Sym(sym) {}
275 
276  explicit operator bool() { return First && Binding; }
277 
278  bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
279  SVal val) override;
280  const MemRegion *getRegion() { return Binding; }
281  };
282 
283  /// iterBindings - Iterate over the bindings in the Store.
284  virtual void iterBindings(Store store, BindingsHandler& f) = 0;
285 
286 protected:
287  const ElementRegion *MakeElementRegion(const SubRegion *baseRegion,
288  QualType pointeeTy,
289  uint64_t index = 0);
290 
291  /// CastRetrievedVal - Used by subclasses of StoreManager to implement
292  /// implicit casts that arise from loads from regions that are reinterpreted
293  /// as another region.
294  SVal CastRetrievedVal(SVal val, const TypedValueRegion *region,
295  QualType castTy);
296 
297 private:
298  SVal getLValueFieldOrIvar(const Decl *decl, SVal base);
299 };
300 
301 inline StoreRef::StoreRef(Store store, StoreManager & smgr)
302  : store(store), mgr(smgr) {
303  if (store)
304  mgr.incrementReferenceCount(store);
305 }
306 
307 inline StoreRef::StoreRef(const StoreRef &sr)
308  : store(sr.store), mgr(sr.mgr)
309 {
310  if (store)
311  mgr.incrementReferenceCount(store);
312 }
313 
315  if (store)
316  mgr.decrementReferenceCount(store);
317 }
318 
319 inline StoreRef &StoreRef::operator=(StoreRef const &newStore) {
320  assert(&newStore.mgr == &mgr);
321  if (store != newStore.store) {
322  mgr.incrementReferenceCount(newStore.store);
323  mgr.decrementReferenceCount(store);
324  store = newStore.getStore();
325  }
326  return *this;
327 }
328 
329 // FIXME: Do we need to pass ProgramStateManager anymore?
330 std::unique_ptr<StoreManager>
332 std::unique_ptr<StoreManager>
334 
335 } // namespace ento
336 
337 } // namespace clang
338 
339 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H
SVal attemptDownCast(SVal Base, QualType DerivedPtrType, bool &Failed)
Attempts to do a down cast.
Definition: Store.cpp:314
virtual DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, const MemRegion *region, QualType EleTy)
Definition: Store.h:153
TypedValueRegion - An abstract class representing regions having a typed value.
Definition: MemRegion.h:530
bool Cast(InterpState &S, CodePtr OpPC)
Definition: Interp.h:803
SVal evalDerivedToBase(SVal Derived, const CastExpr *Cast)
Evaluates a chain of derived-to-base casts through the path specified in Cast.
Definition: Store.cpp:248
A (possibly-)qualified type.
Definition: Type.h:643
MemRegion - The root abstract class for all memory regions.
Definition: MemRegion.h:94
Store getStore() const
Definition: StoreRef.h:46
Information about invalidation for a particular region/symbol.
Definition: MemRegion.h:1445
C Language Family Type Representation.
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
The l-value was an access to a declared entity or something equivalently strong, like the address of ...
virtual StoreRef invalidateRegions(Store store, ArrayRef< SVal > Values, const Expr *E, unsigned Count, const LocationContext *LCtx, const CallEvent *Call, InvalidatedSymbols &IS, RegionAndSymbolInvalidationTraits &ITraits, InvalidatedRegions *InvalidatedTopLevel, InvalidatedRegions *Invalidated)=0
invalidateRegions - Clears out the specified regions from the store, marking their values as unknown...
Represents a path from a specific derived class (which is not represented as part of the path) to a p...
A utility class that visits the reachable symbols using a custom SymbolVisitor.
Definition: ProgramState.h:857
virtual StoreRef BindDefaultZero(Store store, const MemRegion *R)=0
Return a store with in which all values within the given region are reset to zero.
virtual StoreRef getInitialStore(const LocationContext *InitLoc)=0
getInitialStore - Returns the initial "empty" store representing the value bindings upon entry to an ...
Represents a variable declaration or definition.
Definition: Decl.h:812
CompoundLiteralExpr - [C99 6.5.2.5].
Definition: Expr.h:3047
StoreRef(Store store, StoreManager &smgr)
Definition: Store.h:301
const void * Store
Store - This opaque type encapsulates an immutable mapping from locations to values.
Definition: StoreRef.h:27
const ElementRegion * GetElementZeroRegion(const SubRegion *R, QualType T)
Definition: Store.cpp:67
virtual SVal getBinding(Store store, Loc loc, QualType T=QualType())=0
Return the value bound to specified location in a given state.
std::unique_ptr< StoreManager > CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr)
const MemRegion * castRegion(const MemRegion *region, QualType CastToTy)
castRegion - Used by ExprEngine::VisitCast to handle casts from a MemRegion* to a specific location t...
Definition: Store.cpp:74
ASTContext & Ctx
Definition: Store.h:60
Symbolic value.
Definition: SymExpr.h:29
virtual void printJson(raw_ostream &Out, Store S, const char *NL, unsigned int Space, bool IsDot) const =0
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
Represents a member of a struct/union/class.
Definition: Decl.h:2615
i32 captured_struct **param SharedsTy A type which contains references the shared variables *param Shareds Context with the list of shared variables from the p *TaskFunction *param Data Additional data for task generation like final * state
Optional< SVal > getDefaultBinding(nonloc::LazyCompoundVal lcv)
Return the default value bound to a LazyCompoundVal.
Definition: Store.h:96
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
SValBuilder & getSValBuilder()
Definition: Store.h:132
virtual void decrementReferenceCount(Store store)
If the StoreManager supports it, decrement the reference count of the specified Store object...
Definition: Store.h:207
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:3120
virtual SVal getLValueField(const FieldDecl *D, SVal Base)
Definition: Store.h:145
StoreRef enterStackFrame(Store store, const CallEvent &Call, const StackFrameContext *CalleeCtx)
enterStackFrame - Let the StoreManager to do something when execution engine is about to execute into...
Definition: Store.cpp:46
virtual SVal getLValueIvar(const ObjCIvarDecl *decl, SVal base)
Definition: Store.cpp:473
virtual StoreRef BindDefaultInitial(Store store, const MemRegion *R, SVal V)=0
Return a store with the specified value bound to all sub-regions of the region.
std::unique_ptr< StoreManager > CreateRegionStoreManager(ProgramStateManager &StMgr)
Loc makeLoc(SymbolRef sym)
Definition: SValBuilder.h:353
StoreRef & operator=(StoreRef const &newStore)
Definition: Store.h:319
This represents one expression.
Definition: Expr.h:108
SValBuilder & svalBuilder
Definition: Store.h:55
#define V(N, I)
Definition: ASTContext.h:2913
const internal::VariadicAllOfMatcher< Decl > decl
Matches declarations.
virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC)
Definition: Store.h:134
#define bool
Definition: stdbool.h:15
virtual StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, SymbolReaper &SymReaper)=0
ProgramStateManager & StateMgr
Definition: Store.h:56
virtual StoreRef Bind(Store store, Loc loc, SVal val)=0
Return a store with the specified value bound to the given location.
virtual Optional< SVal > getDefaultBinding(Store store, const MemRegion *R)=0
Return the default value bound to a region in a given store.
virtual StoreRef killBinding(Store ST, Loc L)=0
Create a new store with the specified binding removed.
SVal - This represents a symbolic expression, which can be either an L-value or an R-value...
Definition: SVals.h:75
A class responsible for cleaning up unused symbols.
const CompoundLiteralRegion * getCompoundLiteralRegion(const CompoundLiteralExpr *CL, const LocationContext *LC)
getCompoundLiteralRegion - Retrieve the region associated with a given CompoundLiteral.
Definition: MemRegion.cpp:973
Dataflow Directional Tag Classes.
virtual void iterBindings(Store store, BindingsHandler &f)=0
iterBindings - Iterate over the bindings in the Store.
const VarRegion * getVarRegion(const VarDecl *D, const LocationContext *LC)
getVarRegion - Retrieve or create the memory region associated with a specified VarDecl and LocationC...
Definition: MemRegion.cpp:845
const void * getStore() const
Definition: SVals.cpp:166
virtual bool includedInBindings(Store store, const MemRegion *region) const =0
Represents an abstract call to a function or method along a particular path.
Definition: CallEvent.h:138
virtual bool scanReachableSymbols(Store S, const MemRegion *R, ScanReachableSymbols &Visitor)=0
Finds the transitive closure of symbols within the given region.
MemRegionManager & getRegionManager()
getRegionManager - Returns the internal RegionManager object that is used to query and manipulate Mem...
Definition: Store.h:130
SubRegion - A region that subsets another larger region.
Definition: MemRegion.h:436
virtual SVal ArrayToPointer(Loc Array, QualType ElementTy)=0
ArrayToPointer - Used by ExprEngine::VistCast to handle implicit conversions between arrays and point...
const ElementRegion * MakeElementRegion(const SubRegion *baseRegion, QualType pointeeTy, uint64_t index=0)
Definition: Store.cpp:60
SVal CastRetrievedVal(SVal val, const TypedValueRegion *region, QualType castTy)
CastRetrievedVal - Used by subclasses of StoreManager to implement implicit casts that arise from loa...
Definition: Store.cpp:399
MemRegionManager & MRMgr
MRMgr - Manages region objects associated with this StoreManager.
Definition: Store.h:59
virtual SVal getLValueElement(QualType elementType, NonLoc offset, SVal Base)
Definition: Store.cpp:477
const TypedValueRegion * getRegion() const
Definition: SVals.cpp:170
virtual bool HandleBinding(StoreManager &SMgr, Store store, const MemRegion *region, SVal val)=0
ObjCIvarDecl - Represents an ObjC instance variable.
Definition: DeclObjC.h:1944
virtual void incrementReferenceCount(Store store)
If the StoreManager supports it, increment the reference count of the specified Store object...
Definition: Store.h:202
ElementRegion is used to represent both array elements and casts.
Definition: MemRegion.h:1083
virtual ~StoreManager()=default
StoreManager(ProgramStateManager &stateMgr)
Definition: Store.cpp:42
Loc getLValueCompoundLiteral(const CompoundLiteralExpr *CL, const LocationContext *LC)
Definition: Store.h:138