llvm/clang/include/clang/Lex/VariadicMacroSupport.h

//===- VariadicMacroSupport.h - state machines and scope guards -*- 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 defines support types to help with preprocessing variadic macro
// (i.e. macros that use: ellipses __VA_ARGS__ ) definitions and
// expansions.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LEX_VARIADICMACROSUPPORT_H
#define LLVM_CLANG_LEX_VARIADICMACROSUPPORT_H

#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/SmallVector.h"

namespace clang {
  class Preprocessor;

  /// An RAII class that tracks when the Preprocessor starts and stops lexing
  /// the definition of a (ISO C/C++) variadic macro.  As an example, this is
  /// useful for unpoisoning and repoisoning certain identifiers (such as
  /// __VA_ARGS__) that are only allowed in this context.  Also, being a friend
  /// of the Preprocessor class allows it to access PP's cached identifiers
  /// directly (as opposed to performing a lookup each time).
  class VariadicMacroScopeGuard { … };

  /// A class for tracking whether we're inside a VA_OPT during a
  /// traversal of the tokens of a variadic macro definition.
  class VAOptDefinitionContext { … };

  /// A class for tracking whether we're inside a VA_OPT during a
  /// traversal of the tokens of a macro during macro expansion.
  class VAOptExpansionContext : VAOptDefinitionContext { … };
}  // end namespace clang

#endif