include/clang/Analysis/PathSensitive/GRState.h

//== GRState*h - Path-Sens. "State" for tracking valuues -----*- C++ -*--==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file defines SymbolID, ExprBindKey, and GRState*
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_ANALYSIS_VALUESTATE_H
#define LLVM_CLANG_ANALYSIS_VALUESTATE_H

// FIXME: Reduce the number of includes.

#include "clang/Analysis/PathSensitive/Environment.h"
#include "clang/Analysis/PathSensitive/Store.h"
#include "clang/Analysis/PathSensitive/ConstraintManager.h"
#include "clang/Analysis/PathSensitive/MemRegion.h"
#include "clang/Analysis/PathSensitive/RValues.h"
#include "clang/Analysis/PathSensitive/GRCoreEngine.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/ASTContext.h"
#include "clang/Analysis/Analyses/LiveVariables.h"

#include "llvm/Support/Casting.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/ImmutableMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Streams.h"

#include <functional>

namespace clang {

class GRStateManager;
class GRTransferFuncs;

//===----------------------------------------------------------------------===//
// GRStateTrait - Traits used by the Generic Data Map of a GRState.
//===----------------------------------------------------------------------===//
  
template <typename T> struct GRStatePartialTrait;

template <typename T> struct GRStateTrait {
  typedef typename T::data_type data_type;
  static inline void* GDMIndex() { return &T::TagInt; }   
  static inline void* MakeVoidPtr(data_type D) { return (void*) D; }
  static inline data_type MakeData(void* const* P) {
    return P ? (data_type) *P : (data_type) 0;
  }
};

//===----------------------------------------------------------------------===//
// GRState- An ImmutableMap type Stmt*/Decl*/Symbols to RVals.
//===----------------------------------------------------------------------===//
  
/// GRState - This class encapsulates the actual data values for
///  for a "state" in our symbolic value tracking.  It is intended to be
///  used as a functional object; that is once it is created and made
///  "persistent" in a FoldingSet its values will never change.
class GRState : public llvm::FoldingSetNode {
public:  
  // Typedefs.  
  typedef llvm::ImmutableSet<llvm::APSInt*>                IntSetTy;
  typedef llvm::ImmutableMap<void*, void*>                 GenericDataMap;  
  
  typedef GRStateManager ManagerTy;
  
private:
  void operator=(const GRState& R) const;
  
  friend class GRStateManager;
  
  Environment Env;
  Store St;

  // FIXME: Make these private.
public:
  GenericDataMap   GDM;
  
public:
  
  /// This ctor is used when creating the first GRState object.
  GRState(const Environment& env,  Store st, GenericDataMap gdm)
    : Env(env),
      St(st),
      GDM(gdm) {}
  
  /// Copy ctor - We must explicitly define this or else the "Next" ptr
  ///  in FoldingSetNode will also get copied.
  GRState(const GRState& RHS)
    : llvm::FoldingSetNode(),
      Env(RHS.Env),
      St(RHS.St),
      GDM(RHS.GDM) {}
  
  /// getEnvironment - Return the environment associated with this state.
  ///  The environment is the mapping from expressions to values.
  const Environment& getEnvironment() const { return Env; }
  
  /// getStore - Return the store associated with this state.  The store
  ///  is a mapping from locations to values.
  Store getStore() const { return St; }
  
  /// getGDM - Return the generic data map associated with this state.
  GenericDataMap getGDM() const { return GDM; }
  
  /// Profile - Profile the contents of a GRState object for use
  ///  in a FoldingSet.
  static void Profile(llvm::FoldingSetNodeID& ID, const GRState* V) {
    V->Env.Profile(ID);
    ID.AddPointer(V->St);
    V->GDM.Profile(ID);
  }

  /// Profile - Used to profile the contents of this object for inclusion
  ///  in a FoldingSet.
  void Profile(llvm::FoldingSetNodeID& ID) const {
    Profile(ID, this);
  }
  
  RVal LookupExpr(Expr* E) const {
    return Env.LookupExpr(E);
  }
  
  // Iterators.
  typedef Environment::seb_iterator seb_iterator;
  seb_iterator seb_begin() const { return Env.seb_begin(); }
  seb_iterator seb_end() const { return Env.beb_end(); }
  
  typedef Environment::beb_iterator beb_iterator;
  beb_iterator beb_begin() const { return Env.beb_begin(); }
  beb_iterator beb_end() const { return Env.beb_end(); }

  // Trait based GDM dispatch.  
  void* const* FindGDM(void* K) const;
  
  template <typename T>
  typename GRStateTrait<T>::data_type
  get() const {
    return GRStateTrait<T>::MakeData(FindGDM(GRStateTrait<T>::GDMIndex()));
  }
  
  template<typename T>
  typename GRStateTrait<T>::lookup_type
  get(typename GRStateTrait<T>::key_type key) const {
    void* const* d = FindGDM(GRStateTrait<T>::GDMIndex());
    return GRStateTrait<T>::Lookup(GRStateTrait<T>::MakeData(d), key);
  }
  
  // State pretty-printing.
  class Printer {
  public:
    virtual ~Printer() {}
    virtual void Print(std::ostream& Out, const GRState* state,
                       const char* nl, const char* sep) = 0;
  };

  void print(std::ostream& Out, StoreManager& StoreMgr,
             ConstraintManager& ConstraintMgr,
             Printer **Beg = 0, Printer **End = 0,
             const char* nl = "\n", const char *sep = "") const; 
  
  // Tags used for the Generic Data Map.
  struct NullDerefTag {
    static int TagInt;
    typedef const RVal* data_type;
  };
};
  
template<> struct GRTrait<GRState*> {
  static inline void* toPtr(GRState* St)  { return (void*) St; }
  static inline GRState* toState(void* P) { return (GRState*) P; }
  static inline void Profile(llvm::FoldingSetNodeID& profile, GRState* St) {    
    // At this point states have already been uniqued.  Just
    // add the pointer.
    profile.AddPointer(St);
  }
};
  
  
class GRStateSet {
  typedef llvm::SmallPtrSet<const GRState*,5> ImplTy;
  ImplTy Impl;  
public:
  GRStateSet() {}

  inline void Add(const GRState* St) {
    Impl.insert(St);
  }
  
  typedef ImplTy::const_iterator iterator;
  
  inline unsigned size() const { return Impl.size();  }
  inline bool empty()    const { return Impl.empty(); }
  
  inline iterator begin() const { return Impl.begin(); }
  inline iterator end() const { return Impl.end();   }
  
  class AutoPopulate {
    GRStateSet& S;
    unsigned StartSize;
    const GRState* St;
  public:
    AutoPopulate(GRStateSet& s, const GRState* st) 
      : S(s), StartSize(S.size()), St(st) {}
    
    ~AutoPopulate() {
      if (StartSize == S.size())
        S.Add(St);
    }
  };
};  
  
//===----------------------------------------------------------------------===//
// GRStateManager - Factory object for GRStates.
//===----------------------------------------------------------------------===//

class GRStateRef;
  
class GRStateManager {
  friend class GRExprEngine;
  friend class GRStateRef;
  
private:
  EnvironmentManager                   EnvMgr;
  llvm::OwningPtr<StoreManager>        StoreMgr;
  llvm::OwningPtr<ConstraintManager>   ConstraintMgr;
  GRState::IntSetTy::Factory           ISetFactory;
  
  GRState::GenericDataMap::Factory     GDMFactory;
  
  typedef llvm::DenseMap<void*,std::pair<void*,void (*)(void*)> > GDMContextsTy;
  GDMContextsTy GDMContexts;
    
  /// Printers - A set of printer objects used for pretty-printing a GRState.
  ///  GRStateManager owns these objects.
  std::vector<GRState::Printer*> Printers;
  
  /// StateSet - FoldingSet containing all the states created for analyzing
  ///  a particular function.  This is used to unique states.
  llvm::FoldingSet<GRState> StateSet;

  /// ValueMgr - Object that manages the data for all created RVals.
  BasicValueFactory BasicVals;

  /// SymMgr - Object that manages the symbol information.
  SymbolManager SymMgr;

  /// Alloc - A BumpPtrAllocator to allocate states.
  llvm::BumpPtrAllocator& Alloc;
  
  /// CurrentStmt - The block-level statement currently being visited.  This
  ///  is set by GRExprEngine.
  Stmt* CurrentStmt;
  
  /// cfg - The CFG for the analyzed function/method.
  CFG& cfg;
    
  /// TF - Object that represents a bundle of transfer functions
  ///  for manipulating and creating RVals.
  GRTransferFuncs* TF;

  /// Liveness - live-variables information of the ValueDecl* and block-level
  /// Expr* in the CFG. Used to get initial store and prune out dead state.
  LiveVariables& Liveness;

private:

  Environment RemoveBlkExpr(const Environment& Env, Expr* E) {
    return EnvMgr.RemoveBlkExpr(Env, E);
  }
  
  // FIXME: Remove when we do lazy initializaton of variable bindings.
//   const GRState* BindVar(const GRState* St, VarDecl* D, RVal V) {
//     return SetRVal(St, getLVal(D), V);
//   }
    
public:
  
  typedef ConstraintManager* (*ConstraintManagerCreator)(GRStateManager&);
  typedef StoreManager* (*StoreManagerCreator)(GRStateManager&);
  
  GRStateManager(ASTContext& Ctx,
                 StoreManagerCreator CreateStoreManager,
                 ConstraintManagerCreator CreateConstraintManager,
                 llvm::BumpPtrAllocator& alloc, CFG& c, LiveVariables& L) 
  : EnvMgr(alloc),
    ISetFactory(alloc),
    GDMFactory(alloc),
    BasicVals(Ctx, alloc),
    SymMgr(alloc),
    Alloc(alloc),
    cfg(c),
    Liveness(L) {
      StoreMgr.reset((*CreateStoreManager)(*this));
      ConstraintMgr.reset((*CreateConstraintManager)(*this));
  }
  
  ~GRStateManager();

  const GRState* getInitialState();
        
  ASTContext& getContext() { return BasicVals.getContext(); }
  BasicValueFactory& getBasicVals() { return BasicVals; }
  const BasicValueFactory& getBasicVals() const { return BasicVals; }
  SymbolManager& getSymbolManager() { return SymMgr; }
  LiveVariables& getLiveVariables() { return Liveness; }
  llvm::BumpPtrAllocator& getAllocator() { return Alloc; }
  MemRegionManager& getRegionManager() { return StoreMgr->getRegionManager(); }

  typedef StoreManager::DeadSymbolsTy DeadSymbolsTy;

  const GRState* AddDecl(const GRState* St, const VarDecl* VD, Expr* Ex, 
                         unsigned Count);

  const GRState* RemoveDeadBindings(const GRState* St, Stmt* Loc, 
                                       const LiveVariables& Liveness,
                                       DeadSymbolsTy& DeadSyms);

  const GRState* RemoveSubExprBindings(const GRState* St) {
    GRState NewSt = *St;
    NewSt.Env = EnvMgr.RemoveSubExprBindings(NewSt.Env);
    return getPersistentState(NewSt);
  }

  
  // Utility methods for getting regions.
  
  VarRegion* getRegion(const VarDecl* D) {
    return getRegionManager().getVarRegion(D);
  }
  
  LVal getLVal(const VarDecl* D) {
    return StoreMgr->getLVal(D);
  }

  // Get the lvalue of expression.
  RVal GetLValue(const GRState* St, const Expr* Ex) {
    // Forward to store manager. The lvalue of an expression is determined by
    // the store manager.
    return StoreMgr->getLValue(St, Ex);
  }

  // Methods that query & manipulate the Environment.
  
  RVal GetRVal(const GRState* St, Expr* Ex) {
    return St->getEnvironment().GetRVal(Ex, BasicVals);
  }

  RVal GetRVal(const GRState* St, const Expr* Ex) {
    return St->getEnvironment().GetRVal(Ex, BasicVals);
  }
  
  RVal GetBlkExprRVal(const GRState* St, Expr* Ex) {
    return St->getEnvironment().GetBlkExprRVal(Ex, BasicVals);
  }
  
  const GRState* SetRVal(const GRState* St, Expr* Ex, RVal V,
                            bool isBlkExpr, bool Invalidate) {
    
    const Environment& OldEnv = St->getEnvironment();
    Environment NewEnv = EnvMgr.SetRVal(OldEnv, Ex, V, isBlkExpr, Invalidate);
    
    if (NewEnv == OldEnv)
      return St;
    
    GRState NewSt = *St;
    NewSt.Env = NewEnv;
    return getPersistentState(NewSt);
  }
  
  const GRState* SetRVal(const GRState* St, Expr* Ex, RVal V,
                         bool Invalidate = true) {
    
    bool isBlkExpr = false;
    
    if (Ex == CurrentStmt) {
      // FIXME: Should this just be an assertion?  When would we want to set
      // the value of a block-level expression if it wasn't CurrentStmt?
      isBlkExpr = cfg.isBlkExpr(Ex);
      
      if (!isBlkExpr)
        return St;
    }
    
    return SetRVal(St, Ex, V, isBlkExpr, Invalidate);
  }
  
  // Methods that manipulate the GDM.
  const GRState* addGDM(const GRState* St, void* Key, void* Data);
  
  // Methods that query or create regions.
  bool hasStackStorage(const MemRegion* R) {
    return getRegionManager().hasStackStorage(R);
  }
  
  // Methods that query & manipulate the Store.

  void iterBindings(const GRState* state, StoreManager::BindingsHandler& F) {
    StoreMgr->iterBindings(state->getStore(), F);
  }
    
  
  RVal GetRVal(const GRState* St, LVal LV, QualType T = QualType()) {
    return StoreMgr->GetRVal(St->getStore(), LV, T);
  }
  
  void SetRVal(GRState& St, LVal LV, RVal V) {
    St.St = StoreMgr->SetRVal(St.St, LV, V);
  }
  
  const GRState* SetRVal(const GRState* St, LVal LV, RVal V);  

  void Unbind(GRState& St, LVal LV) {
    St.St = StoreMgr->Remove(St.St, LV);
  }
  
  const GRState* Unbind(const GRState* St, LVal LV);
  
  const GRState* getPersistentState(GRState& Impl);
  
  bool isEqual(const GRState* state, Expr* Ex, const llvm::APSInt& V);
  bool isEqual(const GRState* state, Expr* Ex, uint64_t);
  
  // Trait based GDM dispatch.  
  template <typename T>
  const GRState* set(const GRState* st, typename GRStateTrait<T>::data_type D) {
    return addGDM(st, GRStateTrait<T>::GDMIndex(),
                  GRStateTrait<T>::MakeVoidPtr(D));
  }
  
  template<typename T>
  const GRState* set(const GRState* st,
                     typename GRStateTrait<T>::key_type K,
                     typename GRStateTrait<T>::value_type V,
                     typename GRStateTrait<T>::context_type C) {
    
    return addGDM(st, GRStateTrait<T>::GDMIndex(), 
     GRStateTrait<T>::MakeVoidPtr(GRStateTrait<T>::Set(st->get<T>(), K, V, C)));
  }
  
  template <typename T>
  const GRState* remove(const GRState* st,
                        typename GRStateTrait<T>::key_type K,
                        typename GRStateTrait<T>::context_type C) {
    
    return addGDM(st, GRStateTrait<T>::GDMIndex(), 
     GRStateTrait<T>::MakeVoidPtr(GRStateTrait<T>::Remove(st->get<T>(), K, C)));
  }
  

  void* FindGDMContext(void* index,
                       void* (*CreateContext)(llvm::BumpPtrAllocator&),
                       void  (*DeleteContext)(void*));
  
  template <typename T>
  typename GRStateTrait<T>::context_type get_context() {
    void* p = FindGDMContext(GRStateTrait<T>::GDMIndex(),
                             GRStateTrait<T>::CreateContext,
                             GRStateTrait<T>::DeleteContext);
    
    return GRStateTrait<T>::MakeContext(p);
  }

  const GRState* Assume(const GRState* St, RVal Cond, bool Assumption,
                           bool& isFeasible) {
    return ConstraintMgr->Assume(St, Cond, Assumption, isFeasible);
  }

  const GRState* AddNE(const GRState* St, SymbolID sym, const llvm::APSInt& V) {
    return ConstraintMgr->AddNE(St, sym, V);
  }

  const llvm::APSInt* getSymVal(const GRState* St, SymbolID sym) {
    return ConstraintMgr->getSymVal(St, sym);
  }
};
  
//===----------------------------------------------------------------------===//
// GRStateRef - A "fat" reference to GRState that also bundles GRStateManager.
//===----------------------------------------------------------------------===//
  
class GRStateRef {
  const GRState* St;
  GRStateManager* Mgr;
public:
  GRStateRef(const GRState* st, GRStateManager& mgr) : St(st), Mgr(&mgr) {}

  const GRState* getState() const { return St; } 
  operator const GRState*() const { return St; }
  GRStateManager& getManager() const { return *Mgr; }
    
  RVal GetRVal(Expr* Ex) {
    return Mgr->GetRVal(St, Ex);
  }
  
  RVal GetBlkExprRVal(Expr* Ex) {  
    return Mgr->GetBlkExprRVal(St, Ex);
  }
  
  RVal GetRVal(LVal LV, QualType T = QualType()) {
    return Mgr->GetRVal(St, LV, T);
  }
  
  GRStateRef SetRVal(Expr* Ex, RVal V, bool isBlkExpr, bool Invalidate) {
    return GRStateRef(Mgr->SetRVal(St, Ex, V, isBlkExpr, Invalidate), *Mgr);
  }
  
  GRStateRef SetRVal(Expr* Ex, RVal V, bool Invalidate = true) {
    return GRStateRef(Mgr->SetRVal(St, Ex, V, Invalidate), *Mgr);
  }
  
  GRStateRef SetRVal(LVal LV, RVal V) {
    GRState StImpl = *St;
    Mgr->SetRVal(StImpl, LV, V);    
    return GRStateRef(Mgr->getPersistentState(StImpl), *Mgr);
  }
  
  GRStateRef Unbind(LVal LV) {
    return GRStateRef(Mgr->Unbind(St, LV), *Mgr);
  }
  
  GRStateRef AddNE(SymbolID sym, const llvm::APSInt& V) {
    return GRStateRef(Mgr->AddNE(St, sym, V), *Mgr);
  }
  
  // Trait based GDM dispatch.
  template<typename T>
  typename GRStateTrait<T>::data_type get() const {
    return St->get<T>();
  }
  
  template<typename T>
  typename GRStateTrait<T>::lookup_type
  get(typename GRStateTrait<T>::key_type key) const {
    return St->get<T>(key);
  }
  
  template<typename T>
  GRStateRef set(typename GRStateTrait<T>::data_type D) {
    return GRStateRef(Mgr->set<T>(St, D), *Mgr);
  }

  template <typename T>
  typename GRStateTrait<T>::context_type get_context() {
    return Mgr->get_context<T>();
  }    

  template<typename T>
  GRStateRef set(typename GRStateTrait<T>::key_type K,
                 typename GRStateTrait<T>::value_type E,
                 typename GRStateTrait<T>::context_type C) {
    return GRStateRef(Mgr->set<T>(St, K, E, C), *Mgr);
  }
  
  template<typename T>
  GRStateRef set(typename GRStateTrait<T>::key_type K,
                 typename GRStateTrait<T>::value_type E) {
    return GRStateRef(Mgr->set<T>(St, K, E, get_context<T>()), *Mgr);
  }  
  
  template<typename T>
  GRStateRef remove(typename GRStateTrait<T>::key_type K,
                    typename GRStateTrait<T>::context_type C) {
    return GRStateRef(Mgr->remove<T>(St, K, C), *Mgr);
  }
  
  template<typename T>
  GRStateRef remove(typename GRStateTrait<T>::key_type K) {
    return GRStateRef(Mgr->remove<T>(St, K, get_context<T>()), *Mgr);
  }
  
  // Pretty-printing.
  void print(std::ostream& Out, const char* nl = "\n",
             const char *sep = "") const;
  
  void printStdErr() const; 
  
  void printDOT(std::ostream& Out) const;
};

} // end clang namespace

#endif