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      1 //== ProgramState.h - Path-sensitive "State" for tracking values -*- C++ -*--=//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines the state of the program along the analysisa path.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_PROGRAMSTATE_H
     15 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_PROGRAMSTATE_H
     16 
     17 #include "clang/Basic/LLVM.h"
     18 #include "clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h"
     19 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicTypeInfo.h"
     20 #include "clang/StaticAnalyzer/Core/PathSensitive/Environment.h"
     21 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h"
     22 #include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
     23 #include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"
     24 #include "clang/StaticAnalyzer/Core/PathSensitive/TaintTag.h"
     25 #include "llvm/ADT/FoldingSet.h"
     26 #include "llvm/ADT/ImmutableMap.h"
     27 #include "llvm/ADT/PointerIntPair.h"
     28 #include "llvm/Support/Allocator.h"
     29 
     30 namespace llvm {
     31 class APSInt;
     32 }
     33 
     34 namespace clang {
     35 class ASTContext;
     36 
     37 namespace ento {
     38 
     39 class CallEvent;
     40 class CallEventManager;
     41 
     42 typedef std::unique_ptr<ConstraintManager>(*ConstraintManagerCreator)(
     43     ProgramStateManager &, SubEngine *);
     44 typedef std::unique_ptr<StoreManager>(*StoreManagerCreator)(
     45     ProgramStateManager &);
     46 
     47 //===----------------------------------------------------------------------===//
     48 // ProgramStateTrait - Traits used by the Generic Data Map of a ProgramState.
     49 //===----------------------------------------------------------------------===//
     50 
     51 template <typename T> struct ProgramStatePartialTrait;
     52 
     53 template <typename T> struct ProgramStateTrait {
     54   typedef typename T::data_type data_type;
     55   static inline void *MakeVoidPtr(data_type D) { return (void*) D; }
     56   static inline data_type MakeData(void *const* P) {
     57     return P ? (data_type) *P : (data_type) 0;
     58   }
     59 };
     60 
     61 /// \class ProgramState
     62 /// ProgramState - This class encapsulates:
     63 ///
     64 ///    1. A mapping from expressions to values (Environment)
     65 ///    2. A mapping from locations to values (Store)
     66 ///    3. Constraints on symbolic values (GenericDataMap)
     67 ///
     68 ///  Together these represent the "abstract state" of a program.
     69 ///
     70 ///  ProgramState is intended to be used as a functional object; that is,
     71 ///  once it is created and made "persistent" in a FoldingSet, its
     72 ///  values will never change.
     73 class ProgramState : public llvm::FoldingSetNode {
     74 public:
     75   typedef llvm::ImmutableSet<llvm::APSInt*>                IntSetTy;
     76   typedef llvm::ImmutableMap<void*, void*>                 GenericDataMap;
     77 
     78 private:
     79   void operator=(const ProgramState& R) = delete;
     80 
     81   friend class ProgramStateManager;
     82   friend class ExplodedGraph;
     83   friend class ExplodedNode;
     84 
     85   ProgramStateManager *stateMgr;
     86   Environment Env;           // Maps a Stmt to its current SVal.
     87   Store store;               // Maps a location to its current value.
     88   GenericDataMap   GDM;      // Custom data stored by a client of this class.
     89   unsigned refCount;
     90 
     91   /// makeWithStore - Return a ProgramState with the same values as the current
     92   ///  state with the exception of using the specified Store.
     93   ProgramStateRef makeWithStore(const StoreRef &store) const;
     94 
     95   void setStore(const StoreRef &storeRef);
     96 
     97 public:
     98   /// This ctor is used when creating the first ProgramState object.
     99   ProgramState(ProgramStateManager *mgr, const Environment& env,
    100           StoreRef st, GenericDataMap gdm);
    101 
    102   /// Copy ctor - We must explicitly define this or else the "Next" ptr
    103   ///  in FoldingSetNode will also get copied.
    104   ProgramState(const ProgramState &RHS);
    105 
    106   ~ProgramState();
    107 
    108   /// Return the ProgramStateManager associated with this state.
    109   ProgramStateManager &getStateManager() const {
    110     return *stateMgr;
    111   }
    112 
    113   /// Return the ConstraintManager.
    114   ConstraintManager &getConstraintManager() const;
    115 
    116   /// getEnvironment - Return the environment associated with this state.
    117   ///  The environment is the mapping from expressions to values.
    118   const Environment& getEnvironment() const { return Env; }
    119 
    120   /// Return the store associated with this state.  The store
    121   ///  is a mapping from locations to values.
    122   Store getStore() const { return store; }
    123 
    124 
    125   /// getGDM - Return the generic data map associated with this state.
    126   GenericDataMap getGDM() const { return GDM; }
    127 
    128   void setGDM(GenericDataMap gdm) { GDM = gdm; }
    129 
    130   /// Profile - Profile the contents of a ProgramState object for use in a
    131   ///  FoldingSet.  Two ProgramState objects are considered equal if they
    132   ///  have the same Environment, Store, and GenericDataMap.
    133   static void Profile(llvm::FoldingSetNodeID& ID, const ProgramState *V) {
    134     V->Env.Profile(ID);
    135     ID.AddPointer(V->store);
    136     V->GDM.Profile(ID);
    137   }
    138 
    139   /// Profile - Used to profile the contents of this object for inclusion
    140   ///  in a FoldingSet.
    141   void Profile(llvm::FoldingSetNodeID& ID) const {
    142     Profile(ID, this);
    143   }
    144 
    145   BasicValueFactory &getBasicVals() const;
    146   SymbolManager &getSymbolManager() const;
    147 
    148   //==---------------------------------------------------------------------==//
    149   // Constraints on values.
    150   //==---------------------------------------------------------------------==//
    151   //
    152   // Each ProgramState records constraints on symbolic values.  These constraints
    153   // are managed using the ConstraintManager associated with a ProgramStateManager.
    154   // As constraints gradually accrue on symbolic values, added constraints
    155   // may conflict and indicate that a state is infeasible (as no real values
    156   // could satisfy all the constraints).  This is the principal mechanism
    157   // for modeling path-sensitivity in ExprEngine/ProgramState.
    158   //
    159   // Various "assume" methods form the interface for adding constraints to
    160   // symbolic values.  A call to 'assume' indicates an assumption being placed
    161   // on one or symbolic values.  'assume' methods take the following inputs:
    162   //
    163   //  (1) A ProgramState object representing the current state.
    164   //
    165   //  (2) The assumed constraint (which is specific to a given "assume" method).
    166   //
    167   //  (3) A binary value "Assumption" that indicates whether the constraint is
    168   //      assumed to be true or false.
    169   //
    170   // The output of "assume*" is a new ProgramState object with the added constraints.
    171   // If no new state is feasible, NULL is returned.
    172   //
    173 
    174   /// Assumes that the value of \p cond is zero (if \p assumption is "false")
    175   /// or non-zero (if \p assumption is "true").
    176   ///
    177   /// This returns a new state with the added constraint on \p cond.
    178   /// If no new state is feasible, NULL is returned.
    179   ProgramStateRef assume(DefinedOrUnknownSVal cond, bool assumption) const;
    180 
    181   /// Assumes both "true" and "false" for \p cond, and returns both
    182   /// corresponding states (respectively).
    183   ///
    184   /// This is more efficient than calling assume() twice. Note that one (but not
    185   /// both) of the returned states may be NULL.
    186   std::pair<ProgramStateRef, ProgramStateRef>
    187   assume(DefinedOrUnknownSVal cond) const;
    188 
    189   ProgramStateRef assumeInBound(DefinedOrUnknownSVal idx,
    190                                DefinedOrUnknownSVal upperBound,
    191                                bool assumption,
    192                                QualType IndexType = QualType()) const;
    193 
    194   /// \brief Check if the given SVal is constrained to zero or is a zero
    195   ///        constant.
    196   ConditionTruthVal isNull(SVal V) const;
    197 
    198   /// Utility method for getting regions.
    199   const VarRegion* getRegion(const VarDecl *D, const LocationContext *LC) const;
    200 
    201   //==---------------------------------------------------------------------==//
    202   // Binding and retrieving values to/from the environment and symbolic store.
    203   //==---------------------------------------------------------------------==//
    204 
    205   /// Create a new state by binding the value 'V' to the statement 'S' in the
    206   /// state's environment.
    207   ProgramStateRef BindExpr(const Stmt *S, const LocationContext *LCtx,
    208                                SVal V, bool Invalidate = true) const;
    209 
    210   ProgramStateRef bindLoc(Loc location,
    211                           SVal V,
    212                           bool notifyChanges = true) const;
    213 
    214   ProgramStateRef bindLoc(SVal location, SVal V) const;
    215 
    216   ProgramStateRef bindDefault(SVal loc, SVal V) const;
    217 
    218   ProgramStateRef killBinding(Loc LV) const;
    219 
    220   /// \brief Returns the state with bindings for the given regions
    221   ///  cleared from the store.
    222   ///
    223   /// Optionally invalidates global regions as well.
    224   ///
    225   /// \param Regions the set of regions to be invalidated.
    226   /// \param E the expression that caused the invalidation.
    227   /// \param BlockCount The number of times the current basic block has been
    228   //         visited.
    229   /// \param CausesPointerEscape the flag is set to true when
    230   ///        the invalidation entails escape of a symbol (representing a
    231   ///        pointer). For example, due to it being passed as an argument in a
    232   ///        call.
    233   /// \param IS the set of invalidated symbols.
    234   /// \param Call if non-null, the invalidated regions represent parameters to
    235   ///        the call and should be considered directly invalidated.
    236   /// \param ITraits information about special handling for a particular
    237   ///        region/symbol.
    238   ProgramStateRef
    239   invalidateRegions(ArrayRef<const MemRegion *> Regions, const Expr *E,
    240                     unsigned BlockCount, const LocationContext *LCtx,
    241                     bool CausesPointerEscape, InvalidatedSymbols *IS = nullptr,
    242                     const CallEvent *Call = nullptr,
    243                     RegionAndSymbolInvalidationTraits *ITraits = nullptr) const;
    244 
    245   ProgramStateRef
    246   invalidateRegions(ArrayRef<SVal> Regions, const Expr *E,
    247                     unsigned BlockCount, const LocationContext *LCtx,
    248                     bool CausesPointerEscape, InvalidatedSymbols *IS = nullptr,
    249                     const CallEvent *Call = nullptr,
    250                     RegionAndSymbolInvalidationTraits *ITraits = nullptr) const;
    251 
    252   /// enterStackFrame - Returns the state for entry to the given stack frame,
    253   ///  preserving the current state.
    254   ProgramStateRef enterStackFrame(const CallEvent &Call,
    255                                   const StackFrameContext *CalleeCtx) const;
    256 
    257   /// Get the lvalue for a variable reference.
    258   Loc getLValue(const VarDecl *D, const LocationContext *LC) const;
    259 
    260   Loc getLValue(const CompoundLiteralExpr *literal,
    261                 const LocationContext *LC) const;
    262 
    263   /// Get the lvalue for an ivar reference.
    264   SVal getLValue(const ObjCIvarDecl *decl, SVal base) const;
    265 
    266   /// Get the lvalue for a field reference.
    267   SVal getLValue(const FieldDecl *decl, SVal Base) const;
    268 
    269   /// Get the lvalue for an indirect field reference.
    270   SVal getLValue(const IndirectFieldDecl *decl, SVal Base) const;
    271 
    272   /// Get the lvalue for an array index.
    273   SVal getLValue(QualType ElementType, SVal Idx, SVal Base) const;
    274 
    275   /// Returns the SVal bound to the statement 'S' in the state's environment.
    276   SVal getSVal(const Stmt *S, const LocationContext *LCtx) const;
    277 
    278   SVal getSValAsScalarOrLoc(const Stmt *Ex, const LocationContext *LCtx) const;
    279 
    280   /// \brief Return the value bound to the specified location.
    281   /// Returns UnknownVal() if none found.
    282   SVal getSVal(Loc LV, QualType T = QualType()) const;
    283 
    284   /// Returns the "raw" SVal bound to LV before any value simplfication.
    285   SVal getRawSVal(Loc LV, QualType T= QualType()) const;
    286 
    287   /// \brief Return the value bound to the specified location.
    288   /// Returns UnknownVal() if none found.
    289   SVal getSVal(const MemRegion* R) const;
    290 
    291   SVal getSValAsScalarOrLoc(const MemRegion *R) const;
    292 
    293   /// \brief Visits the symbols reachable from the given SVal using the provided
    294   /// SymbolVisitor.
    295   ///
    296   /// This is a convenience API. Consider using ScanReachableSymbols class
    297   /// directly when making multiple scans on the same state with the same
    298   /// visitor to avoid repeated initialization cost.
    299   /// \sa ScanReachableSymbols
    300   bool scanReachableSymbols(SVal val, SymbolVisitor& visitor) const;
    301 
    302   /// \brief Visits the symbols reachable from the SVals in the given range
    303   /// using the provided SymbolVisitor.
    304   bool scanReachableSymbols(const SVal *I, const SVal *E,
    305                             SymbolVisitor &visitor) const;
    306 
    307   /// \brief Visits the symbols reachable from the regions in the given
    308   /// MemRegions range using the provided SymbolVisitor.
    309   bool scanReachableSymbols(const MemRegion * const *I,
    310                             const MemRegion * const *E,
    311                             SymbolVisitor &visitor) const;
    312 
    313   template <typename CB> CB scanReachableSymbols(SVal val) const;
    314   template <typename CB> CB scanReachableSymbols(const SVal *beg,
    315                                                  const SVal *end) const;
    316 
    317   template <typename CB> CB
    318   scanReachableSymbols(const MemRegion * const *beg,
    319                        const MemRegion * const *end) const;
    320 
    321   /// Create a new state in which the statement is marked as tainted.
    322   ProgramStateRef addTaint(const Stmt *S, const LocationContext *LCtx,
    323                                TaintTagType Kind = TaintTagGeneric) const;
    324 
    325   /// Create a new state in which the symbol is marked as tainted.
    326   ProgramStateRef addTaint(SymbolRef S,
    327                                TaintTagType Kind = TaintTagGeneric) const;
    328 
    329   /// Create a new state in which the region symbol is marked as tainted.
    330   ProgramStateRef addTaint(const MemRegion *R,
    331                                TaintTagType Kind = TaintTagGeneric) const;
    332 
    333   /// Check if the statement is tainted in the current state.
    334   bool isTainted(const Stmt *S, const LocationContext *LCtx,
    335                  TaintTagType Kind = TaintTagGeneric) const;
    336   bool isTainted(SVal V, TaintTagType Kind = TaintTagGeneric) const;
    337   bool isTainted(SymbolRef Sym, TaintTagType Kind = TaintTagGeneric) const;
    338   bool isTainted(const MemRegion *Reg, TaintTagType Kind=TaintTagGeneric) const;
    339 
    340   /// \brief Get dynamic type information for a region.
    341   DynamicTypeInfo getDynamicTypeInfo(const MemRegion *Reg) const;
    342 
    343   /// \brief Set dynamic type information of the region; return the new state.
    344   ProgramStateRef setDynamicTypeInfo(const MemRegion *Reg,
    345                                      DynamicTypeInfo NewTy) const;
    346 
    347   /// \brief Set dynamic type information of the region; return the new state.
    348   ProgramStateRef setDynamicTypeInfo(const MemRegion *Reg,
    349                                      QualType NewTy,
    350                                      bool CanBeSubClassed = true) const {
    351     return setDynamicTypeInfo(Reg, DynamicTypeInfo(NewTy, CanBeSubClassed));
    352   }
    353 
    354   //==---------------------------------------------------------------------==//
    355   // Accessing the Generic Data Map (GDM).
    356   //==---------------------------------------------------------------------==//
    357 
    358   void *const* FindGDM(void *K) const;
    359 
    360   template<typename T>
    361   ProgramStateRef add(typename ProgramStateTrait<T>::key_type K) const;
    362 
    363   template <typename T>
    364   typename ProgramStateTrait<T>::data_type
    365   get() const {
    366     return ProgramStateTrait<T>::MakeData(FindGDM(ProgramStateTrait<T>::GDMIndex()));
    367   }
    368 
    369   template<typename T>
    370   typename ProgramStateTrait<T>::lookup_type
    371   get(typename ProgramStateTrait<T>::key_type key) const {
    372     void *const* d = FindGDM(ProgramStateTrait<T>::GDMIndex());
    373     return ProgramStateTrait<T>::Lookup(ProgramStateTrait<T>::MakeData(d), key);
    374   }
    375 
    376   template <typename T>
    377   typename ProgramStateTrait<T>::context_type get_context() const;
    378 
    379 
    380   template<typename T>
    381   ProgramStateRef remove(typename ProgramStateTrait<T>::key_type K) const;
    382 
    383   template<typename T>
    384   ProgramStateRef remove(typename ProgramStateTrait<T>::key_type K,
    385                         typename ProgramStateTrait<T>::context_type C) const;
    386   template <typename T>
    387   ProgramStateRef remove() const;
    388 
    389   template<typename T>
    390   ProgramStateRef set(typename ProgramStateTrait<T>::data_type D) const;
    391 
    392   template<typename T>
    393   ProgramStateRef set(typename ProgramStateTrait<T>::key_type K,
    394                      typename ProgramStateTrait<T>::value_type E) const;
    395 
    396   template<typename T>
    397   ProgramStateRef set(typename ProgramStateTrait<T>::key_type K,
    398                      typename ProgramStateTrait<T>::value_type E,
    399                      typename ProgramStateTrait<T>::context_type C) const;
    400 
    401   template<typename T>
    402   bool contains(typename ProgramStateTrait<T>::key_type key) const {
    403     void *const* d = FindGDM(ProgramStateTrait<T>::GDMIndex());
    404     return ProgramStateTrait<T>::Contains(ProgramStateTrait<T>::MakeData(d), key);
    405   }
    406 
    407   // Pretty-printing.
    408   void print(raw_ostream &Out, const char *nl = "\n",
    409              const char *sep = "") const;
    410   void printDOT(raw_ostream &Out) const;
    411   void printTaint(raw_ostream &Out, const char *nl = "\n",
    412                   const char *sep = "") const;
    413 
    414   void dump() const;
    415   void dumpTaint() const;
    416 
    417 private:
    418   friend void ProgramStateRetain(const ProgramState *state);
    419   friend void ProgramStateRelease(const ProgramState *state);
    420 
    421   /// \sa invalidateValues()
    422   /// \sa invalidateRegions()
    423   ProgramStateRef
    424   invalidateRegionsImpl(ArrayRef<SVal> Values,
    425                         const Expr *E, unsigned BlockCount,
    426                         const LocationContext *LCtx,
    427                         bool ResultsInSymbolEscape,
    428                         InvalidatedSymbols *IS,
    429                         RegionAndSymbolInvalidationTraits *HTraits,
    430                         const CallEvent *Call) const;
    431 };
    432 
    433 //===----------------------------------------------------------------------===//
    434 // ProgramStateManager - Factory object for ProgramStates.
    435 //===----------------------------------------------------------------------===//
    436 
    437 class ProgramStateManager {
    438   friend class ProgramState;
    439   friend void ProgramStateRelease(const ProgramState *state);
    440 private:
    441   /// Eng - The SubEngine that owns this state manager.
    442   SubEngine *Eng; /* Can be null. */
    443 
    444   EnvironmentManager                   EnvMgr;
    445   std::unique_ptr<StoreManager>        StoreMgr;
    446   std::unique_ptr<ConstraintManager>   ConstraintMgr;
    447 
    448   ProgramState::GenericDataMap::Factory     GDMFactory;
    449 
    450   typedef llvm::DenseMap<void*,std::pair<void*,void (*)(void*)> > GDMContextsTy;
    451   GDMContextsTy GDMContexts;
    452 
    453   /// StateSet - FoldingSet containing all the states created for analyzing
    454   ///  a particular function.  This is used to unique states.
    455   llvm::FoldingSet<ProgramState> StateSet;
    456 
    457   /// Object that manages the data for all created SVals.
    458   std::unique_ptr<SValBuilder> svalBuilder;
    459 
    460   /// Manages memory for created CallEvents.
    461   std::unique_ptr<CallEventManager> CallEventMgr;
    462 
    463   /// A BumpPtrAllocator to allocate states.
    464   llvm::BumpPtrAllocator &Alloc;
    465 
    466   /// A vector of ProgramStates that we can reuse.
    467   std::vector<ProgramState *> freeStates;
    468 
    469 public:
    470   ProgramStateManager(ASTContext &Ctx,
    471                  StoreManagerCreator CreateStoreManager,
    472                  ConstraintManagerCreator CreateConstraintManager,
    473                  llvm::BumpPtrAllocator& alloc,
    474                  SubEngine *subeng);
    475 
    476   ~ProgramStateManager();
    477 
    478   ProgramStateRef getInitialState(const LocationContext *InitLoc);
    479 
    480   ASTContext &getContext() { return svalBuilder->getContext(); }
    481   const ASTContext &getContext() const { return svalBuilder->getContext(); }
    482 
    483   BasicValueFactory &getBasicVals() {
    484     return svalBuilder->getBasicValueFactory();
    485   }
    486 
    487   SValBuilder &getSValBuilder() {
    488     return *svalBuilder;
    489   }
    490 
    491   SymbolManager &getSymbolManager() {
    492     return svalBuilder->getSymbolManager();
    493   }
    494   const SymbolManager &getSymbolManager() const {
    495     return svalBuilder->getSymbolManager();
    496   }
    497 
    498   llvm::BumpPtrAllocator& getAllocator() { return Alloc; }
    499 
    500   MemRegionManager& getRegionManager() {
    501     return svalBuilder->getRegionManager();
    502   }
    503   const MemRegionManager& getRegionManager() const {
    504     return svalBuilder->getRegionManager();
    505   }
    506 
    507   CallEventManager &getCallEventManager() { return *CallEventMgr; }
    508 
    509   StoreManager& getStoreManager() { return *StoreMgr; }
    510   ConstraintManager& getConstraintManager() { return *ConstraintMgr; }
    511   SubEngine* getOwningEngine() { return Eng; }
    512 
    513   ProgramStateRef removeDeadBindings(ProgramStateRef St,
    514                                     const StackFrameContext *LCtx,
    515                                     SymbolReaper& SymReaper);
    516 
    517 public:
    518 
    519   SVal ArrayToPointer(Loc Array, QualType ElementTy) {
    520     return StoreMgr->ArrayToPointer(Array, ElementTy);
    521   }
    522 
    523   // Methods that manipulate the GDM.
    524   ProgramStateRef addGDM(ProgramStateRef St, void *Key, void *Data);
    525   ProgramStateRef removeGDM(ProgramStateRef state, void *Key);
    526 
    527   // Methods that query & manipulate the Store.
    528 
    529   void iterBindings(ProgramStateRef state, StoreManager::BindingsHandler& F) {
    530     StoreMgr->iterBindings(state->getStore(), F);
    531   }
    532 
    533   ProgramStateRef getPersistentState(ProgramState &Impl);
    534   ProgramStateRef getPersistentStateWithGDM(ProgramStateRef FromState,
    535                                            ProgramStateRef GDMState);
    536 
    537   bool haveEqualEnvironments(ProgramStateRef S1, ProgramStateRef S2) {
    538     return S1->Env == S2->Env;
    539   }
    540 
    541   bool haveEqualStores(ProgramStateRef S1, ProgramStateRef S2) {
    542     return S1->store == S2->store;
    543   }
    544 
    545   //==---------------------------------------------------------------------==//
    546   // Generic Data Map methods.
    547   //==---------------------------------------------------------------------==//
    548   //
    549   // ProgramStateManager and ProgramState support a "generic data map" that allows
    550   // different clients of ProgramState objects to embed arbitrary data within a
    551   // ProgramState object.  The generic data map is essentially an immutable map
    552   // from a "tag" (that acts as the "key" for a client) and opaque values.
    553   // Tags/keys and values are simply void* values.  The typical way that clients
    554   // generate unique tags are by taking the address of a static variable.
    555   // Clients are responsible for ensuring that data values referred to by a
    556   // the data pointer are immutable (and thus are essentially purely functional
    557   // data).
    558   //
    559   // The templated methods below use the ProgramStateTrait<T> class
    560   // to resolve keys into the GDM and to return data values to clients.
    561   //
    562 
    563   // Trait based GDM dispatch.
    564   template <typename T>
    565   ProgramStateRef set(ProgramStateRef st, typename ProgramStateTrait<T>::data_type D) {
    566     return addGDM(st, ProgramStateTrait<T>::GDMIndex(),
    567                   ProgramStateTrait<T>::MakeVoidPtr(D));
    568   }
    569 
    570   template<typename T>
    571   ProgramStateRef set(ProgramStateRef st,
    572                      typename ProgramStateTrait<T>::key_type K,
    573                      typename ProgramStateTrait<T>::value_type V,
    574                      typename ProgramStateTrait<T>::context_type C) {
    575 
    576     return addGDM(st, ProgramStateTrait<T>::GDMIndex(),
    577      ProgramStateTrait<T>::MakeVoidPtr(ProgramStateTrait<T>::Set(st->get<T>(), K, V, C)));
    578   }
    579 
    580   template <typename T>
    581   ProgramStateRef add(ProgramStateRef st,
    582                      typename ProgramStateTrait<T>::key_type K,
    583                      typename ProgramStateTrait<T>::context_type C) {
    584     return addGDM(st, ProgramStateTrait<T>::GDMIndex(),
    585         ProgramStateTrait<T>::MakeVoidPtr(ProgramStateTrait<T>::Add(st->get<T>(), K, C)));
    586   }
    587 
    588   template <typename T>
    589   ProgramStateRef remove(ProgramStateRef st,
    590                         typename ProgramStateTrait<T>::key_type K,
    591                         typename ProgramStateTrait<T>::context_type C) {
    592 
    593     return addGDM(st, ProgramStateTrait<T>::GDMIndex(),
    594      ProgramStateTrait<T>::MakeVoidPtr(ProgramStateTrait<T>::Remove(st->get<T>(), K, C)));
    595   }
    596 
    597   template <typename T>
    598   ProgramStateRef remove(ProgramStateRef st) {
    599     return removeGDM(st, ProgramStateTrait<T>::GDMIndex());
    600   }
    601 
    602   void *FindGDMContext(void *index,
    603                        void *(*CreateContext)(llvm::BumpPtrAllocator&),
    604                        void  (*DeleteContext)(void*));
    605 
    606   template <typename T>
    607   typename ProgramStateTrait<T>::context_type get_context() {
    608     void *p = FindGDMContext(ProgramStateTrait<T>::GDMIndex(),
    609                              ProgramStateTrait<T>::CreateContext,
    610                              ProgramStateTrait<T>::DeleteContext);
    611 
    612     return ProgramStateTrait<T>::MakeContext(p);
    613   }
    614 
    615   void EndPath(ProgramStateRef St) {
    616     ConstraintMgr->EndPath(St);
    617   }
    618 };
    619 
    620 
    621 //===----------------------------------------------------------------------===//
    622 // Out-of-line method definitions for ProgramState.
    623 //===----------------------------------------------------------------------===//
    624 
    625 inline ConstraintManager &ProgramState::getConstraintManager() const {
    626   return stateMgr->getConstraintManager();
    627 }
    628 
    629 inline const VarRegion* ProgramState::getRegion(const VarDecl *D,
    630                                                 const LocationContext *LC) const
    631 {
    632   return getStateManager().getRegionManager().getVarRegion(D, LC);
    633 }
    634 
    635 inline ProgramStateRef ProgramState::assume(DefinedOrUnknownSVal Cond,
    636                                       bool Assumption) const {
    637   if (Cond.isUnknown())
    638     return this;
    639 
    640   return getStateManager().ConstraintMgr
    641       ->assume(this, Cond.castAs<DefinedSVal>(), Assumption);
    642 }
    643 
    644 inline std::pair<ProgramStateRef , ProgramStateRef >
    645 ProgramState::assume(DefinedOrUnknownSVal Cond) const {
    646   if (Cond.isUnknown())
    647     return std::make_pair(this, this);
    648 
    649   return getStateManager().ConstraintMgr
    650       ->assumeDual(this, Cond.castAs<DefinedSVal>());
    651 }
    652 
    653 inline ProgramStateRef ProgramState::bindLoc(SVal LV, SVal V) const {
    654   if (Optional<Loc> L = LV.getAs<Loc>())
    655     return bindLoc(*L, V);
    656   return this;
    657 }
    658 
    659 inline Loc ProgramState::getLValue(const VarDecl *VD,
    660                                const LocationContext *LC) const {
    661   return getStateManager().StoreMgr->getLValueVar(VD, LC);
    662 }
    663 
    664 inline Loc ProgramState::getLValue(const CompoundLiteralExpr *literal,
    665                                const LocationContext *LC) const {
    666   return getStateManager().StoreMgr->getLValueCompoundLiteral(literal, LC);
    667 }
    668 
    669 inline SVal ProgramState::getLValue(const ObjCIvarDecl *D, SVal Base) const {
    670   return getStateManager().StoreMgr->getLValueIvar(D, Base);
    671 }
    672 
    673 inline SVal ProgramState::getLValue(const FieldDecl *D, SVal Base) const {
    674   return getStateManager().StoreMgr->getLValueField(D, Base);
    675 }
    676 
    677 inline SVal ProgramState::getLValue(const IndirectFieldDecl *D,
    678                                     SVal Base) const {
    679   StoreManager &SM = *getStateManager().StoreMgr;
    680   for (const auto *I : D->chain()) {
    681     Base = SM.getLValueField(cast<FieldDecl>(I), Base);
    682   }
    683 
    684   return Base;
    685 }
    686 
    687 inline SVal ProgramState::getLValue(QualType ElementType, SVal Idx, SVal Base) const{
    688   if (Optional<NonLoc> N = Idx.getAs<NonLoc>())
    689     return getStateManager().StoreMgr->getLValueElement(ElementType, *N, Base);
    690   return UnknownVal();
    691 }
    692 
    693 inline SVal ProgramState::getSVal(const Stmt *Ex,
    694                                   const LocationContext *LCtx) const{
    695   return Env.getSVal(EnvironmentEntry(Ex, LCtx),
    696                      *getStateManager().svalBuilder);
    697 }
    698 
    699 inline SVal
    700 ProgramState::getSValAsScalarOrLoc(const Stmt *S,
    701                                    const LocationContext *LCtx) const {
    702   if (const Expr *Ex = dyn_cast<Expr>(S)) {
    703     QualType T = Ex->getType();
    704     if (Ex->isGLValue() || Loc::isLocType(T) ||
    705         T->isIntegralOrEnumerationType())
    706       return getSVal(S, LCtx);
    707   }
    708 
    709   return UnknownVal();
    710 }
    711 
    712 inline SVal ProgramState::getRawSVal(Loc LV, QualType T) const {
    713   return getStateManager().StoreMgr->getBinding(getStore(), LV, T);
    714 }
    715 
    716 inline SVal ProgramState::getSVal(const MemRegion* R) const {
    717   return getStateManager().StoreMgr->getBinding(getStore(),
    718                                                 loc::MemRegionVal(R));
    719 }
    720 
    721 inline BasicValueFactory &ProgramState::getBasicVals() const {
    722   return getStateManager().getBasicVals();
    723 }
    724 
    725 inline SymbolManager &ProgramState::getSymbolManager() const {
    726   return getStateManager().getSymbolManager();
    727 }
    728 
    729 template<typename T>
    730 ProgramStateRef ProgramState::add(typename ProgramStateTrait<T>::key_type K) const {
    731   return getStateManager().add<T>(this, K, get_context<T>());
    732 }
    733 
    734 template <typename T>
    735 typename ProgramStateTrait<T>::context_type ProgramState::get_context() const {
    736   return getStateManager().get_context<T>();
    737 }
    738 
    739 template<typename T>
    740 ProgramStateRef ProgramState::remove(typename ProgramStateTrait<T>::key_type K) const {
    741   return getStateManager().remove<T>(this, K, get_context<T>());
    742 }
    743 
    744 template<typename T>
    745 ProgramStateRef ProgramState::remove(typename ProgramStateTrait<T>::key_type K,
    746                                typename ProgramStateTrait<T>::context_type C) const {
    747   return getStateManager().remove<T>(this, K, C);
    748 }
    749 
    750 template <typename T>
    751 ProgramStateRef ProgramState::remove() const {
    752   return getStateManager().remove<T>(this);
    753 }
    754 
    755 template<typename T>
    756 ProgramStateRef ProgramState::set(typename ProgramStateTrait<T>::data_type D) const {
    757   return getStateManager().set<T>(this, D);
    758 }
    759 
    760 template<typename T>
    761 ProgramStateRef ProgramState::set(typename ProgramStateTrait<T>::key_type K,
    762                             typename ProgramStateTrait<T>::value_type E) const {
    763   return getStateManager().set<T>(this, K, E, get_context<T>());
    764 }
    765 
    766 template<typename T>
    767 ProgramStateRef ProgramState::set(typename ProgramStateTrait<T>::key_type K,
    768                             typename ProgramStateTrait<T>::value_type E,
    769                             typename ProgramStateTrait<T>::context_type C) const {
    770   return getStateManager().set<T>(this, K, E, C);
    771 }
    772 
    773 template <typename CB>
    774 CB ProgramState::scanReachableSymbols(SVal val) const {
    775   CB cb(this);
    776   scanReachableSymbols(val, cb);
    777   return cb;
    778 }
    779 
    780 template <typename CB>
    781 CB ProgramState::scanReachableSymbols(const SVal *beg, const SVal *end) const {
    782   CB cb(this);
    783   scanReachableSymbols(beg, end, cb);
    784   return cb;
    785 }
    786 
    787 template <typename CB>
    788 CB ProgramState::scanReachableSymbols(const MemRegion * const *beg,
    789                                  const MemRegion * const *end) const {
    790   CB cb(this);
    791   scanReachableSymbols(beg, end, cb);
    792   return cb;
    793 }
    794 
    795 /// \class ScanReachableSymbols
    796 /// A Utility class that allows to visit the reachable symbols using a custom
    797 /// SymbolVisitor.
    798 class ScanReachableSymbols {
    799   typedef llvm::DenseSet<const void*> VisitedItems;
    800 
    801   VisitedItems visited;
    802   ProgramStateRef state;
    803   SymbolVisitor &visitor;
    804 public:
    805 
    806   ScanReachableSymbols(ProgramStateRef st, SymbolVisitor& v)
    807     : state(st), visitor(v) {}
    808 
    809   bool scan(nonloc::LazyCompoundVal val);
    810   bool scan(nonloc::CompoundVal val);
    811   bool scan(SVal val);
    812   bool scan(const MemRegion *R);
    813   bool scan(const SymExpr *sym);
    814 };
    815 
    816 } // end ento namespace
    817 
    818 } // end clang namespace
    819 
    820 #endif
    821