llvm/clang/include/clang/Basic/Linkage.h

//===- Linkage.h - Linkage enumeration and utilities ------------*- 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
//
//===----------------------------------------------------------------------===//
//
/// \file
/// Defines the Linkage enumeration and various utility functions.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_BASIC_LINKAGE_H
#define LLVM_CLANG_BASIC_LINKAGE_H

#include "llvm/Support/ErrorHandling.h"
#include <utility>

namespace clang {

/// Describes the different kinds of linkage
/// (C++ [basic.link], C99 6.2.2) that an entity may have.
enum class Linkage : unsigned char { … };

/// Describes the different kinds of language linkage
/// (C++ [dcl.link]) that an entity may have.
enum LanguageLinkage { … };

/// A more specific kind of linkage than enum Linkage.
///
/// This is relevant to CodeGen and AST file reading.
enum GVALinkage { … };

inline bool isDiscardableGVALinkage(GVALinkage L) { … }

/// Do we know that this will be the only definition of this symbol (excluding
/// inlining-only definitions)?
inline bool isUniqueGVALinkage(GVALinkage L) { … }

inline bool isExternallyVisible(Linkage L) { … }

inline Linkage getFormalLinkage(Linkage L) { … }

inline bool isExternalFormalLinkage(Linkage L) { … }

/// Compute the minimum linkage given two linkages.
///
/// The linkage can be interpreted as a pair formed by the formal linkage and
/// a boolean for external visibility. This is just what getFormalLinkage and
/// isExternallyVisible return. We want the minimum of both components. The
/// Linkage enum is defined in an order that makes this simple, we just need
/// special cases for when VisibleNoLinkage would lose the visible bit and
/// become NoLinkage.
inline Linkage minLinkage(Linkage L1, Linkage L2) { … }

} // namespace clang

#endif // LLVM_CLANG_BASIC_LINKAGE_H