- //===- 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 
-