PointerEmbeddedInt.h [plain text]
#ifndef LLVM_ADT_POINTEREMBEDDEDINT_H
#define LLVM_ADT_POINTEREMBEDDEDINT_H
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/PointerLikeTypeTraits.h"
#include <climits>
namespace llvm {
template <typename IntT, int Bits = sizeof(IntT) * CHAR_BIT>
class PointerEmbeddedInt {
uintptr_t Value;
static_assert(Bits < sizeof(uintptr_t) * CHAR_BIT,
"Cannot embed more bits than we have in a pointer!");
enum : uintptr_t {
Shift = sizeof(uintptr_t) * CHAR_BIT - Bits,
Mask = static_cast<uintptr_t>(-1) << Bits
};
static constexpr const struct RawValueTag {} RawValue = RawValueTag();
friend class PointerLikeTypeTraits<PointerEmbeddedInt>;
explicit PointerEmbeddedInt(uintptr_t Value, RawValueTag) : Value(Value) {}
public:
PointerEmbeddedInt() : Value(0) {}
PointerEmbeddedInt(IntT I) {
*this = I;
}
PointerEmbeddedInt &operator=(IntT I) {
assert((std::is_signed<IntT>::value ? llvm::isInt<Bits>(I)
: llvm::isUInt<Bits>(I)) &&
"Integer has bits outside those preserved!");
Value = static_cast<uintptr_t>(I) << Shift;
return *this;
}
operator IntT() const {
if (std::is_signed<IntT>::value)
return static_cast<IntT>(static_cast<intptr_t>(Value) >> Shift);
return static_cast<IntT>(Value >> Shift);
}
};
template <typename IntT, int Bits>
class PointerLikeTypeTraits<PointerEmbeddedInt<IntT, Bits>> {
typedef PointerEmbeddedInt<IntT, Bits> T;
public:
static inline void *getAsVoidPointer(const T &P) {
return reinterpret_cast<void *>(P.Value);
}
static inline T getFromVoidPointer(void *P) {
return T(reinterpret_cast<uintptr_t>(P), T::RawValue);
}
static inline T getFromVoidPointer(const void *P) {
return T(reinterpret_cast<uintptr_t>(P), T::RawValue);
}
enum { NumLowBitsAvailable = T::Shift };
};
template <typename IntT, int Bits>
struct DenseMapInfo<PointerEmbeddedInt<IntT, Bits>> {
typedef PointerEmbeddedInt<IntT, Bits> T;
typedef DenseMapInfo<IntT> IntInfo;
static inline T getEmptyKey() { return IntInfo::getEmptyKey(); }
static inline T getTombstoneKey() { return IntInfo::getTombstoneKey(); }
static unsigned getHashValue(const T &Arg) {
return IntInfo::getHashValue(Arg);
}
static bool isEqual(const T &LHS, const T &RHS) { return LHS == RHS; }
};
}
#endif