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//===- llvm/SymbolTableListTraits.h - Traits for iplist ---------*- 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 a generic class that is used to implement the automatic

// symbol table manipulation that occurs when you put (for example) a named

// instruction into a basic block.

//

// The way that this is implemented is by using a special traits class with the

// intrusive list that makes up the list of instructions in a basic block.  When

// a new element is added to the list of instructions, the traits class is

// notified, allowing the symbol table to be updated.

//

// This generic class implements the traits class.  It must be generic so that

// it can work for all uses it, which include lists of instructions, basic

// blocks, arguments, functions, global variables, etc...

//

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

#ifndef LLVM_IR_SYMBOLTABLELISTTRAITS_H

#define LLVM_IR_SYMBOLTABLELISTTRAITS_H

#include "llvm/ADT/ilist.h"

#include "llvm/ADT/simple_ilist.h"

#include <cstddef>

namespace llvm {

class Argument;

class BasicBlock;

class Function;

class GlobalAlias;

class GlobalIFunc;

class GlobalVariable;

class Instruction;

class Module;

class ValueSymbolTable;

/// Template metafunction to get the parent type for a symbol table list.

///

/// Implementations create a typedef called \c type so that we only need a

/// single template parameter for the list and traits.

template <typename NodeTy> struct SymbolTableListParentType {};

#define DEFINE_SYMBOL_TABLE_PARENT_TYPE(NODE, PARENT)                          \

  template <> struct SymbolTableListParentType<NODE> { using type = PARENT; };

DEFINE_SYMBOL_TABLE_PARENT_TYPE(Instruction, BasicBlock)

DEFINE_SYMBOL_TABLE_PARENT_TYPE(BasicBlock, Function)

DEFINE_SYMBOL_TABLE_PARENT_TYPE(Argument, Function)

DEFINE_SYMBOL_TABLE_PARENT_TYPE(Function, Module)

DEFINE_SYMBOL_TABLE_PARENT_TYPE(GlobalVariable, Module)

DEFINE_SYMBOL_TABLE_PARENT_TYPE(GlobalAlias, Module)

DEFINE_SYMBOL_TABLE_PARENT_TYPE(GlobalIFunc, Module)

#undef DEFINE_SYMBOL_TABLE_PARENT_TYPE

template <typename NodeTy> class SymbolTableList;

// ValueSubClass   - The type of objects that I hold, e.g. Instruction.

// ItemParentClass - The type of object that owns the list, e.g. BasicBlock.

//

template <typename ValueSubClass>

class SymbolTableListTraits : public ilist_alloc_traits<ValueSubClass> {

  using ListTy = SymbolTableList<ValueSubClass>;

  using iterator = typename simple_ilist<ValueSubClass>::iterator;

  using ItemParentClass =

      typename SymbolTableListParentType<ValueSubClass>::type;

public:

  SymbolTableListTraits() = default;

private:

  /// getListOwner - Return the object that owns this list.  If this is a list

  /// of instructions, it returns the BasicBlock that owns them.

  ItemParentClass *getListOwner() {

    size_t Offset = reinterpret_cast<size_t>(

        &((ItemParentClass *)nullptr->*ItemParentClass::getSublistAccess(

                                           static_cast<ValueSubClass *>(

                                               nullptr))));

    ListTy *Anchor = static_cast<ListTy *>(this);

    return reinterpret_cast<ItemParentClass*>(reinterpret_cast<char*>(Anchor)-

                                              Offset);

  }

  static ListTy &getList(ItemParentClass *Par) {

    return Par->*(Par->getSublistAccess((ValueSubClass*)nullptr));

  }

  static ValueSymbolTable *getSymTab(ItemParentClass *Par) {

    return Par ? toPtr(Par->getValueSymbolTable()) : nullptr;

  }

public:

  void addNodeToList(ValueSubClass *V);

  void removeNodeFromList(ValueSubClass *V);

  void transferNodesFromList(SymbolTableListTraits &L2, iterator first,

                             iterator last);

  // private:

  template<typename TPtr>

  void setSymTabObject(TPtr *, TPtr);

  static ValueSymbolTable *toPtr(ValueSymbolTable *P) { return P; }

  static ValueSymbolTable *toPtr(ValueSymbolTable &R) { return &R; }

};

/// List that automatically updates parent links and symbol tables.

///

/// When nodes are inserted into and removed from this list, the associated

/// symbol table will be automatically updated.  Similarly, parent links get

/// updated automatically.

template <class T>

class SymbolTableList

    : public iplist_impl<simple_ilist<T>, SymbolTableListTraits<T>> {};

} // end namespace llvm

#endif // LLVM_IR_SYMBOLTABLELISTTRAITS_H