llvm/llvm/include/llvm/Support/TypeSize.h

//===- TypeSize.h - Wrapper around type sizes -------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides a struct that can be used to query the size of IR types
// which may be scalable vectors. It provides convenience operators so that
// it can be used in much the same way as a single scalar value.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_TYPESIZE_H
#define LLVM_SUPPORT_TYPESIZE_H

#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"

#include <algorithm>
#include <cassert>
#include <cstdint>
#include <type_traits>

namespace llvm {

/// Reports a diagnostic message to indicate an invalid size request has been
/// done on a scalable vector. This function may not return.
void reportInvalidSizeRequest(const char *Msg);

/// StackOffset holds a fixed and a scalable offset in bytes.
class StackOffset { … };

namespace details {

// Base class for ElementCount and TypeSize below.
template <typename LeafTy, typename ValueTy> class FixedOrScalableQuantity { … };

} // namespace details

// Stores the number of elements for a type and whether this type is fixed
// (N-Elements) or scalable (e.g., SVE).
//  - ElementCount::getFixed(1) : A scalar value.
//  - ElementCount::getFixed(2) : A vector type holding 2 values.
//  - ElementCount::getScalable(4) : A scalable vector type holding 4 values.
class ElementCount
    : public details::FixedOrScalableQuantity<ElementCount, unsigned> { … };

// Stores the size of a type. If the type is of fixed size, it will represent
// the exact size. If the type is a scalable vector, it will represent the known
// minimum size.
class TypeSize : public details::FixedOrScalableQuantity<TypeSize, uint64_t> { … };

//===----------------------------------------------------------------------===//
// Utilities
//===----------------------------------------------------------------------===//

/// Returns a TypeSize with a known minimum size that is the next integer
/// (mod 2**64) that is greater than or equal to \p Quantity and is a multiple
/// of \p Align. \p Align must be non-zero.
///
/// Similar to the alignTo functions in MathExtras.h
inline constexpr TypeSize alignTo(TypeSize Size, uint64_t Align) { … }

/// Stream operator function for `FixedOrScalableQuantity`.
template <typename LeafTy, typename ScalarTy>
inline raw_ostream &
operator<<(raw_ostream &OS,
           const details::FixedOrScalableQuantity<LeafTy, ScalarTy> &PS) { … }

template <> struct DenseMapInfo<ElementCount, void> { … };

} // end namespace llvm

#endif // LLVM_SUPPORT_TYPESIZE_H