llvm/clang/include/clang/AST/ODRHash.h

//===-- ODRHash.h - Hashing to diagnose ODR failures ------------*- 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
/// This file contains the declaration of the ODRHash class, which calculates
/// a hash based on AST nodes, which is stable across different runs.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_ODRHASH_H
#define LLVM_CLANG_AST_ODRHASH_H

#include "clang/AST/DeclarationName.h"
#include "clang/AST/Type.h"
#include "clang/AST/TemplateBase.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/SmallVector.h"

namespace clang {

class APValue;
class Decl;
class IdentifierInfo;
class NestedNameSpecifier;
class Stmt;
class TemplateParameterList;

// ODRHash is used to calculate a hash based on AST node contents that
// does not rely on pointer addresses.  This allows the hash to not vary
// between runs and is usable to detect ODR problems in modules.  To use,
// construct an ODRHash object, then call Add* methods over the nodes that
// need to be hashed.  Then call CalculateHash to get the hash value.
// Typically, only one Add* call is needed.  clear can be called to reuse the
// object.
class ODRHash { … };

}  // end namespace clang

#endif