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