Analysis/RValues.h

//== RValues.h - Abstract RValues for Path-Sens. Value Tracking -*- C++ -*--==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This files defines RValue, LValue, and NonLValue, classes that represent
//  abstract r-values for use with path-sensitive value tracking.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_ANALYSIS_RVALUE_H
#define LLVM_CLANG_ANALYSIS_RVALUE_H

// FIXME: reduce the number of includes.

#include "clang/Analysis/PathSensitive/GREngine.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/SmallPtrSet.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Streams.h"

#include <functional>

//==------------------------------------------------------------------------==//
//  Values and ValueManager.
//==------------------------------------------------------------------------==// 

namespace clang {

class SymbolID {
  unsigned Data;
public:
  SymbolID() : Data(~0) {}
  SymbolID(unsigned x) : Data(x) {}
  
  bool isInitialized() const { return Data != (unsigned) ~0; }
  operator unsigned() const { assert (isInitialized()); return Data; }

  void Profile(llvm::FoldingSetNodeID& ID) const { 
    assert (isInitialized());
    ID.AddInteger(Data);
  }

  static inline void Profile(llvm::FoldingSetNodeID& ID, SymbolID X) {
    X.Profile(ID);
  }
};
  
class SymbolData {
  uintptr_t Data;
public:
  enum Kind { ParmKind = 0x0, Mask = 0x3 };
  
  SymbolData(ParmVarDecl* D)
  : Data(reinterpret_cast<uintptr_t>(D) | ParmKind) {}
  
  inline Kind getKind() const { return (Kind) (Data & Mask); }
  inline void* getPtr() const { return reinterpret_cast<void*>(Data & ~Mask); }  
  inline bool operator==(const SymbolData& R) const { return Data == R.Data; }  
};
  

class SymIntConstraint : public llvm::FoldingSetNode {
  SymbolID Symbol;
  BinaryOperator::Opcode Op;
  const llvm::APSInt& Val;
public:  
  SymIntConstraint(SymbolID sym, BinaryOperator::Opcode op, 
                   const llvm::APSInt& V)
    : Symbol(sym),
      Op(op), Val(V) {}
  
  BinaryOperator::Opcode getOpcode() const { return Op; }
  SymbolID getSymbol() const { return Symbol; }
  const llvm::APSInt& getInt() const { return Val; }
  
  static inline void Profile(llvm::FoldingSetNodeID& ID,
                             const SymbolID& Symbol,
                             BinaryOperator::Opcode Op,
                             const llvm::APSInt& Val) {
    Symbol.Profile(ID);
    ID.AddInteger(Op);
    ID.AddPointer(&Val);
  }
  
  void Profile(llvm::FoldingSetNodeID& ID) {
    Profile(ID, Symbol, Op, Val);
  }
};
  

class SymbolManager {
  std::vector<SymbolData> SymbolToData;
  
  typedef llvm::DenseMap<void*,SymbolID> MapTy;
  MapTy DataToSymbol;
  
public:
  SymbolManager();
  ~SymbolManager();
  
  SymbolData getSymbolData(SymbolID id) const {
    assert (id < SymbolToData.size());
    return SymbolToData[id];
  }
  
  SymbolID getSymbol(ParmVarDecl* D);
};
  

class ValueManager {
  typedef llvm::FoldingSet<llvm::FoldingSetNodeWrapper<llvm::APSInt> >
          APSIntSetTy;
  
  typedef llvm::FoldingSet<SymIntConstraint>
          SymIntCSetTy;
  
  
  ASTContext& Ctx;
  llvm::BumpPtrAllocator& BPAlloc;
  
  APSIntSetTy   APSIntSet;
  SymIntCSetTy  SymIntCSet;
  
public:
  ValueManager(ASTContext& ctx, llvm::BumpPtrAllocator& Alloc) 
    : Ctx(ctx), BPAlloc(Alloc) {}
  
  ~ValueManager();
  
  ASTContext& getContext() const { return Ctx; }  
  const llvm::APSInt& getValue(const llvm::APSInt& X);
  const llvm::APSInt& getValue(uint64_t X, unsigned BitWidth, bool isUnsigned);
  const llvm::APSInt& getValue(uint64_t X, QualType T,
                               SourceLocation Loc = SourceLocation());
  
  const SymIntConstraint& getConstraint(SymbolID sym, BinaryOperator::Opcode Op,
                                        const llvm::APSInt& V);
};

//==------------------------------------------------------------------------==//
//  Base RValue types.
//==------------------------------------------------------------------------==// 

class RValue {
public:
  enum BaseKind { LValueKind=0x0,
                  NonLValueKind=0x1,
                  UninitializedKind=0x2,
                  InvalidKind=0x3 };
  
  enum { BaseBits = 2, 
         BaseMask = 0x3 };
  
private:
  void* Data;
  unsigned Kind;
  
protected:
  RValue(const void* d, bool isLValue, unsigned ValKind)
  : Data(const_cast<void*>(d)),
    Kind((isLValue ? LValueKind : NonLValueKind) | (ValKind << BaseBits)) {}
  
  explicit RValue(BaseKind k)
    : Data(0), Kind(k) {}
  
  void* getRawPtr() const {
    return reinterpret_cast<void*>(Data);
  }
  
public:
  ~RValue() {};
  
  /// BufferTy - A temporary buffer to hold a set of RValues.
  typedef llvm::SmallVector<RValue,5> BufferTy;

  
  RValue Cast(ValueManager& ValMgr, Expr* CastExpr) const;
  
  unsigned getRawKind() const { return Kind; }
  BaseKind getBaseKind() const { return (BaseKind) (Kind & BaseMask); }
  unsigned getSubKind() const { return (Kind & ~BaseMask) >> BaseBits; }
  
  void Profile(llvm::FoldingSetNodeID& ID) const {
    ID.AddInteger((unsigned) getRawKind());
    ID.AddPointer(reinterpret_cast<void*>(Data));
  }
  
  bool operator==(const RValue& RHS) const {
    return getRawKind() == RHS.getRawKind() && Data == RHS.Data;
  }
  
  static RValue GetSymbolValue(SymbolManager& SymMgr, ParmVarDecl *D);
  
  inline bool isValid() const { return getRawKind() != InvalidKind; }
  inline bool isInvalid() const { return getRawKind() == InvalidKind; }
  
  void print(std::ostream& OS) const;
  void print() const { print(*llvm::cerr.stream()); }
  
  // Implement isa<T> support.
  static inline bool classof(const RValue*) { return true; }
};

class InvalidValue : public RValue {
public:
  InvalidValue() : RValue(InvalidKind) {}
  
  static inline bool classof(const RValue* V) {
    return V->getBaseKind() == InvalidKind;
  }  
};

class UninitializedValue : public RValue {
public:
  UninitializedValue() : RValue(UninitializedKind) {}
  
  static inline bool classof(const RValue* V) {
    return V->getBaseKind() == UninitializedKind;
  }  
};

class NonLValue : public RValue {
protected:
  NonLValue(unsigned SubKind, const void* d) : RValue(d, false, SubKind) {}
  
public:
  void print(std::ostream& Out) const;
  
  RValue Cast(ValueManager& ValMgr, Expr* CastExpr) const;

  // Arithmetic operators.
  NonLValue Add(ValueManager& ValMgr, const NonLValue& RHS) const;
  NonLValue Sub(ValueManager& ValMgr, const NonLValue& RHS) const;
  NonLValue Mul(ValueManager& ValMgr, const NonLValue& RHS) const;
  NonLValue Div(ValueManager& ValMgr, const NonLValue& RHS) const;
  NonLValue Rem(ValueManager& ValMgr, const NonLValue& RHS) const;
  NonLValue UnaryMinus(ValueManager& ValMgr, UnaryOperator* U) const;
  NonLValue BitwiseComplement(ValueManager& ValMgr) const;
  
  // Equality operators.
  NonLValue EQ(ValueManager& ValMgr, const NonLValue& RHS) const;
  NonLValue NE(ValueManager& ValMgr, const NonLValue& RHS) const;
  
  
  // Utility methods to create NonLValues.
  static NonLValue GetValue(ValueManager& ValMgr, uint64_t X, QualType T,
                            SourceLocation Loc = SourceLocation());
  
  static NonLValue GetValue(ValueManager& ValMgr, IntegerLiteral* I);
  
  static inline NonLValue GetIntTruthValue(ValueManager& ValMgr, bool X) {
    return GetValue(ValMgr, X ? 1U : 0U, ValMgr.getContext().IntTy);
  }
  
  // Implement isa<T> support.
  static inline bool classof(const RValue* V) {
    return V->getBaseKind() >= NonLValueKind;
  }
};

class LValue : public RValue {
protected:
  LValue(unsigned SubKind, const void* D) : RValue(const_cast<void*>(D), 
                                                   true, SubKind) {}
  
public:
  void print(std::ostream& Out) const;
  
  RValue Cast(ValueManager& ValMgr, Expr* CastExpr) const;

  // Equality operators.
  NonLValue EQ(ValueManager& ValMgr, const LValue& RHS) const;
  NonLValue NE(ValueManager& ValMgr, const LValue& RHS) const;
  
  // Implement isa<T> support.
  static inline bool classof(const RValue* V) {
    return V->getBaseKind() == LValueKind;
  }
};
  
//==------------------------------------------------------------------------==//
//  Subclasses of NonLValue.
//==------------------------------------------------------------------------==// 

enum NonLValueKind { SymbolicNonLValueKind, ConcreteIntKind, NumNonLValueKind };

class SymbolicNonLValue : public NonLValue {
public:
  SymbolicNonLValue(unsigned SymID)
  : NonLValue(SymbolicNonLValueKind,
              reinterpret_cast<void*>((uintptr_t) SymID)) {}
  
  SymbolID getSymbolID() const {
    return (SymbolID) reinterpret_cast<uintptr_t>(getRawPtr());
  }
  
  static inline bool classof(const RValue* V) {
    return V->getSubKind() == SymbolicNonLValueKind;
  }  
};

class ConcreteInt : public NonLValue {
public:
  ConcreteInt(const llvm::APSInt& V) : NonLValue(ConcreteIntKind, &V) {}
  
  const llvm::APSInt& getValue() const {
    return *static_cast<llvm::APSInt*>(getRawPtr());
  }
  
  // Arithmetic operators.
  
  ConcreteInt Add(ValueManager& ValMgr, const ConcreteInt& V) const {
    return ValMgr.getValue(getValue() + V.getValue());
  }
  
  ConcreteInt Sub(ValueManager& ValMgr, const ConcreteInt& V) const {
    return ValMgr.getValue(getValue() - V.getValue());
  }
  
  ConcreteInt Mul(ValueManager& ValMgr, const ConcreteInt& V) const {
    return ValMgr.getValue(getValue() * V.getValue());
  }
  
  ConcreteInt Div(ValueManager& ValMgr, const ConcreteInt& V) const {
    return ValMgr.getValue(getValue() / V.getValue());
  }
  
  ConcreteInt Rem(ValueManager& ValMgr, const ConcreteInt& V) const {
    return ValMgr.getValue(getValue() % V.getValue());
  }
  
  ConcreteInt UnaryMinus(ValueManager& ValMgr, UnaryOperator* U) const {
    assert (U->getType() == U->getSubExpr()->getType());  
    assert (U->getType()->isIntegerType());  
    return ValMgr.getValue(-getValue()); 
  }
  
  ConcreteInt BitwiseComplement(ValueManager& ValMgr) const {
    return ValMgr.getValue(~getValue()); 
  }
  
  // Casting.
  
  ConcreteInt Cast(ValueManager& ValMgr, Expr* CastExpr) const {
    assert (CastExpr->getType()->isIntegerType());
    
    llvm::APSInt X(getValue());  
    X.extOrTrunc(ValMgr.getContext().getTypeSize(CastExpr->getType(),
                                                 CastExpr->getLocStart()));
    return ValMgr.getValue(X);
  }
  
  // Equality operators.
  
  ConcreteInt EQ(ValueManager& ValMgr, const ConcreteInt& V) const {
    const llvm::APSInt& Val = getValue();    
    return ValMgr.getValue(Val == V.getValue() ? 1U : 0U,
                           Val.getBitWidth(), Val.isUnsigned());
  }
  
  ConcreteInt NE(ValueManager& ValMgr, const ConcreteInt& V) const {
    const llvm::APSInt& Val = getValue();    
    return ValMgr.getValue(Val != V.getValue() ? 1U : 0U,
                           Val.getBitWidth(), Val.isUnsigned());
  }
  
  // Implement isa<T> support.
  static inline bool classof(const RValue* V) {
    return V->getSubKind() == ConcreteIntKind;
  }
};

//==------------------------------------------------------------------------==//
//  Subclasses of LValue.
//==------------------------------------------------------------------------==// 

enum LValueKind { SymbolicLValueKind, LValueDeclKind, ConcreteIntLValueKind,
                  NumLValueKind };
  
class SymbolicLValue : public LValue {
public:
  SymbolicLValue(unsigned SymID)
  : LValue(SymbolicLValueKind, reinterpret_cast<void*>((uintptr_t) SymID)) {}
  
  SymbolID getSymbolID() const {
    return (SymbolID) reinterpret_cast<uintptr_t>(getRawPtr());
  }
  
  static inline bool classof(const RValue* V) {
    return V->getSubKind() == SymbolicLValueKind;
  }  
};

class LValueDecl : public LValue {
public:
  LValueDecl(const ValueDecl* vd) : LValue(LValueDeclKind,vd) {}
  
  ValueDecl* getDecl() const {
    return static_cast<ValueDecl*>(getRawPtr());
  }
  
  inline bool operator==(const LValueDecl& R) const {
    return getDecl() == R.getDecl();
  }
  
  inline bool operator!=(const LValueDecl& R) const {
    return getDecl() != R.getDecl();
  }
  
  // Implement isa<T> support.
  static inline bool classof(const RValue* V) {
    return V->getSubKind() == LValueDeclKind;
  }
};

class ConcreteIntLValue : public LValue {
public:
  ConcreteIntLValue(const llvm::APSInt& V) : LValue(ConcreteIntLValueKind, &V) {}
  
  const llvm::APSInt& getValue() const {
    return *static_cast<llvm::APSInt*>(getRawPtr());
  }
  
  // Arithmetic operators.
  
  ConcreteIntLValue Add(ValueManager& ValMgr, const ConcreteInt& V) const {
    return ValMgr.getValue(getValue() + V.getValue());
  }
  
  ConcreteIntLValue Sub(ValueManager& ValMgr, const ConcreteInt& V) const {
    return ValMgr.getValue(getValue() - V.getValue());
  }
  
  // Equality operators.
  
  ConcreteInt EQ(ValueManager& ValMgr, const ConcreteIntLValue& V) const {
    const llvm::APSInt& Val = getValue();    
    return ValMgr.getValue(Val == V.getValue() ? 1U : 0U,
                           Val.getBitWidth(), Val.isUnsigned());
  }
  
  ConcreteInt NE(ValueManager& ValMgr, const ConcreteIntLValue& V) const {
    const llvm::APSInt& Val = getValue();    
    return ValMgr.getValue(Val != V.getValue() ? 1U : 0U,
                           Val.getBitWidth(), Val.isUnsigned());
  }
  
  // Implement isa<T> support.
  static inline bool classof(const RValue* V) {
    return V->getSubKind() == ConcreteIntLValueKind;
  }
};  
  
} // end clang namespace  

//==------------------------------------------------------------------------==//
// Casting machinery to get cast<> and dyn_cast<> working with SymbolData.
//==------------------------------------------------------------------------==//

namespace llvm {

template<> inline bool
isa<clang::ParmVarDecl,clang::SymbolData>(const clang::SymbolData& V) {
  return V.getKind() == clang::SymbolData::ParmKind;
}

template<> struct cast_retty_impl<clang::ParmVarDecl,clang::SymbolData> {
  typedef const clang::ParmVarDecl* ret_type;
};

template<> struct simplify_type<clang::SymbolData> {
  typedef void* SimpleType;
  static inline SimpleType getSimplifiedValue(const clang::SymbolData &V) {
    return V.getPtr();
  }
};

} // end llvm namespace

#endif