GEPTypeBridgeIterator.h

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// GEPTypeBridgeIterator
//
//
#ifndef SVF_GEPTYPEBRIDGEITERATOR_H
#define SVF_GEPTYPEBRIDGEITERATOR_H
 
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/User.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
 
namespace llvm
{
 
template<typename ItTy = User::const_op_iterator>
class generic_bridge_gep_type_iterator
{
 
    ItTy OpIt;
    PointerIntPair<Type*,1> CurTy;
    unsigned AddrSpace;
    generic_bridge_gep_type_iterator() {}
public:
    using iterator_category = std::forward_iterator_tag;
    using value_type = Type*;
    using difference_type = ptrdiff_t;
    using pointer = Type**;
    using reference = Type*&;
 
    static generic_bridge_gep_type_iterator begin(Type* Ty, ItTy It)
    {
        generic_bridge_gep_type_iterator I;
        I.CurTy.setPointer(Ty);
        I.OpIt = It;
        return I;
    }
 
    static generic_bridge_gep_type_iterator begin(Type* Ty, unsigned AddrSpace,
            ItTy It)
    {
        generic_bridge_gep_type_iterator I;
        I.CurTy.setPointer(Ty);
        I.CurTy.setInt(true);
        I.AddrSpace = AddrSpace;
        I.OpIt = It;
        return I;
    }
 
    static generic_bridge_gep_type_iterator end(ItTy It)
    {
        generic_bridge_gep_type_iterator I;
        I.OpIt = It;
        return I;
    }
 
    bool operator==(const generic_bridge_gep_type_iterator& x) const
    {
        return OpIt == x.OpIt;
    }
 
    bool operator!=(const generic_bridge_gep_type_iterator& x) const
    {
        return !operator==(x);
    }
 
    Type* operator*() const
    {
        if ( CurTy.getInt() )
            return PointerType::get(CurTy.getPointer()->getContext(), AddrSpace);
        return CurTy.getPointer();
    }
 
    Type* getIndexedType() const
    {
        assert(false && "needs to be refactored");
        if ( CurTy.getInt() )
            return CurTy.getPointer();
        Type*  CT = CurTy.getPointer();
        if (auto ST = dyn_cast<StructType>(CT))
            return ST->getTypeAtIndex(getOperand());
        else if (auto Array = dyn_cast<ArrayType>(CT))
            return Array->getElementType();
        else if (auto Vector = dyn_cast<VectorType>(CT))
            return Vector->getElementType();
        else
            return CT;
    }
 
// non-standard operators, these may not need be bridged but seems it's
// prudent to do so...
    Type* operator->() const
    {
        return operator*();
    }
 
    Value* getOperand() const
    {
        return const_cast<Value*>(&**OpIt);
    }
 
 
    generic_bridge_gep_type_iterator& operator++()
    {
        if ( CurTy.getInt() )
        {
            CurTy.setInt(false);
        }
        else if ( Type*  CT = CurTy.getPointer() )
        {
            if (auto ST = dyn_cast<StructType>(CT))
                CurTy.setPointer(ST->getTypeAtIndex(getOperand()));
            else if (auto Array = dyn_cast<ArrayType>(CT))
                CurTy.setPointer(Array->getElementType());
            else if (auto Vector = dyn_cast<VectorType>(CT))
                CurTy.setPointer(Vector->getElementType());
            else
                CurTy.setPointer(nullptr);
        }
        else
        {
            CurTy.setPointer(nullptr);
        }
        ++OpIt;
        return *this;
    }
 
 
    generic_bridge_gep_type_iterator operator++(int)
    {
        generic_bridge_gep_type_iterator tmp = *this;
        ++*this;
        return tmp;
    }
 
};
 
 
typedef generic_bridge_gep_type_iterator<> bridge_gep_iterator;
 
inline bridge_gep_iterator bridge_gep_begin(const User* GEP)
{
    auto *GEPOp = llvm::cast<GEPOperator>(GEP);
    return bridge_gep_iterator::begin(GEPOp->getSourceElementType(),
                                      llvm::cast<PointerType>(GEPOp->getPointerOperandType()->getScalarType())->getAddressSpace(),
                                      GEP->op_begin() + 1);
}
 
inline bridge_gep_iterator bridge_gep_end(const User* GEP)
{
    return bridge_gep_iterator::end(GEP->op_end());
}
 
inline bridge_gep_iterator bridge_gep_begin(const User &GEP)
{
    auto &GEPOp = llvm::cast<GEPOperator>(GEP);
    return bridge_gep_iterator::begin( GEPOp.getSourceElementType(),
                                       llvm::cast<PointerType>(GEPOp.getPointerOperandType()->getScalarType())->getAddressSpace(),
                                       GEP.op_begin() + 1);
}
 
inline bridge_gep_iterator bridge_gep_end(const User &GEP)
{
    return bridge_gep_iterator::end(GEP.op_end());
}
 
template<typename T>
inline generic_bridge_gep_type_iterator<const T*> bridge_gep_end( Type*  /*Op0*/, ArrayRef<T> A )
{
    return generic_bridge_gep_type_iterator<const T*>::end(A.end());
}
 
} // End namespace llvm
 
#endif