AccessPath.h

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//===- AccessPath.h -- Location set of abstract object-----------------------//
//
//                     SVF: Static Value-Flow Analysis
//
// Copyright (C) <2013->  <Yulei Sui>
//
 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
 
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//
//===----------------------------------------------------------------------===//
 
/*
 * @file: AccessPath.h
 * @author: yesen
 * @date: 26 Sep 2014
 *
 * LICENSE
 *
 */
 
 
#ifndef AccessPath_H_
#define AccessPath_H_
 
 
#include "SVFIR/SVFValue.h"
 
 
namespace SVF
{
 
class SVFVar;
 
 
/*
* Location set represents a set of locations in a memory block with following offsets:
*     { offset + \sum_{i=0}^N (stride_i * j_i) | 0 \leq j_i < M_i }
* where N is the size of number-stride pair vector, M_i (stride_i) is i-th number (stride)
* in the number-stride pair vector.
*/
class AccessPath
{
    friend class SymbolTableInfo;
    friend class SVFIRWriter;
    friend class SVFIRReader;
 
public:
    enum LSRelation
    {
        NonOverlap, Overlap, Subset, Superset, Same
    };
 
    typedef std::pair<const SVFVar*, const SVFType*> IdxOperandPair;
    typedef std::vector<IdxOperandPair> IdxOperandPairs;
 
    AccessPath(APOffset o = 0, const SVFType* srcTy = nullptr) : fldIdx(o), gepPointeeType(srcTy) {}
 
    AccessPath(const AccessPath& ap)
        : fldIdx(ap.fldIdx),
          idxOperandPairs(ap.getIdxOperandPairVec()),
          gepPointeeType(ap.gepSrcPointeeType())
    {
    }
 
    ~AccessPath() {}
 
 
    AccessPath operator+(const AccessPath& rhs) const;
    bool operator<(const AccessPath& rhs) const;
    inline const AccessPath& operator=(const AccessPath& rhs)
    {
        fldIdx = rhs.fldIdx;
        idxOperandPairs = rhs.getIdxOperandPairVec();
        gepPointeeType = rhs.gepPointeeType;
        return *this;
    }
    inline bool operator==(const AccessPath& rhs) const
    {
        return this->fldIdx == rhs.fldIdx &&
               this->idxOperandPairs == rhs.idxOperandPairs && this->gepPointeeType == rhs.gepPointeeType;
    }
 
 
    inline APOffset getConstantStructFldIdx() const
    {
        return fldIdx;
    }
    inline void setFldIdx(APOffset idx)
    {
        fldIdx = idx;
    }
    inline const IdxOperandPairs& getIdxOperandPairVec() const
    {
        return idxOperandPairs;
    }
    inline const SVFType* gepSrcPointeeType() const
    {
        return gepPointeeType;
    }
 
    APOffset computeConstantByteOffset() const;
 
    APOffset computeConstantOffset() const;
 
    u32_t getElementNum(const SVFType* type) const;
 
 
    bool addOffsetVarAndGepTypePair(const SVFVar* var, const SVFType* gepIterType);
 
    bool isConstantOffset() const;
 
    inline bool intersects(const AccessPath& RHS) const
    {
        return computeAllLocations().intersects(RHS.computeAllLocations());
    }
 
    u32_t getStructFieldOffset(const SVFVar* idxOperandVar, const SVFStructType* idxOperandType) const;
 
    std::string dump() const;
 
private:
 
    LSRelation checkRelation(const AccessPath& LHS, const AccessPath& RHS);
 
    NodeBS computeAllLocations() const;
 
    APOffset fldIdx;    
    IdxOperandPairs idxOperandPairs;    
    const SVFType* gepPointeeType;   
};
 
} // End namespace SVF
 
template <> struct std::hash<SVF::AccessPath>
{
    size_t operator()(const SVF::AccessPath &ap) const
    {
        SVF::Hash<std::pair<SVF::NodeID, SVF::NodeID>> h;
        std::hash<SVF::AccessPath::IdxOperandPairs> v;
        return h(std::make_pair(ap.getConstantStructFldIdx(),
                                v(ap.getIdxOperandPairVec())));
    }
};
 
#endif /* AccessPath_H_ */