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//===- llvm/IR/Comdat.h - Comdat definitions --------------------*- 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 Comdat class, which represents a

/// single COMDAT in LLVM.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_COMDAT_H

#define LLVM_IR_COMDAT_H

#include "llvm-c/Types.h"

#include "llvm/ADT/SmallPtrSet.h"

#include "llvm/Support/CBindingWrapping.h"

namespace llvm {

class GlobalObject;

class raw_ostream;

class StringRef;

template <typename ValueTy> class StringMapEntry;

// This is a Name X SelectionKind pair. The reason for having this be an

// independent object instead of just adding the name and the SelectionKind

// to a GlobalObject is that it is invalid to have two Comdats with the same

// name but different SelectionKind. This structure makes that unrepresentable.

class Comdat {

public:

  enum SelectionKind {

    Any,           ///< The linker may choose any COMDAT.

    ExactMatch,    ///< The data referenced by the COMDAT must be the same.

    Largest,       ///< The linker will choose the largest COMDAT.

    NoDeduplicate, ///< No deduplication is performed.

    SameSize,      ///< The data referenced by the COMDAT must be the same size.

  };

  Comdat(const Comdat &) = delete;

  Comdat(Comdat &&C);

  SelectionKind getSelectionKind() const { return SK; }

  void setSelectionKind(SelectionKind Val) { SK = Val; }

  StringRef getName() const;

  void print(raw_ostream &OS, bool IsForDebug = false) const;

  void dump() const;

  const SmallPtrSetImpl<GlobalObject *> &getUsers() const { return Users; }

private:

  friend class Module;

  friend class GlobalObject;

  Comdat();

  void addUser(GlobalObject *GO);

  void removeUser(GlobalObject *GO);

  // Points to the map in Module.

  StringMapEntry<Comdat> *Name = nullptr;

  SelectionKind SK = Any;

  // Globals using this comdat.

  SmallPtrSet<GlobalObject *, 2> Users;

};

// Create wrappers for C Binding types (see CBindingWrapping.h).

DEFINE_SIMPLE_CONVERSION_FUNCTIONS(Comdat, LLVMComdatRef)

inline raw_ostream &operator<<(raw_ostream &OS, const Comdat &C) {

  C.print(OS);

  return OS;

}

} // end namespace llvm

#endif // LLVM_IR_COMDAT_H