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      1 //===-- llvm/SymbolTableListTraits.h - Traits for iplist --------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines a generic class that is used to implement the automatic
     11 // symbol table manipulation that occurs when you put (for example) a named
     12 // instruction into a basic block.
     13 //
     14 // The way that this is implemented is by using a special traits class with the
     15 // intrusive list that makes up the list of instructions in a basic block.  When
     16 // a new element is added to the list of instructions, the traits class is
     17 // notified, allowing the symbol table to be updated.
     18 //
     19 // This generic class implements the traits class.  It must be generic so that
     20 // it can work for all uses it, which include lists of instructions, basic
     21 // blocks, arguments, functions, global variables, etc...
     22 //
     23 //===----------------------------------------------------------------------===//
     24 
     25 #ifndef LLVM_IR_SYMBOLTABLELISTTRAITS_H
     26 #define LLVM_IR_SYMBOLTABLELISTTRAITS_H
     27 
     28 #include "llvm/ADT/ilist.h"
     29 
     30 namespace llvm {
     31 class ValueSymbolTable;
     32 
     33 template<typename NodeTy> class ilist_iterator;
     34 template<typename NodeTy, typename Traits> class iplist;
     35 template<typename Ty> struct ilist_traits;
     36 
     37 // ValueSubClass   - The type of objects that I hold, e.g. Instruction.
     38 // ItemParentClass - The type of object that owns the list, e.g. BasicBlock.
     39 //
     40 template<typename ValueSubClass, typename ItemParentClass>
     41 class SymbolTableListTraits : public ilist_default_traits<ValueSubClass> {
     42   typedef ilist_traits<ValueSubClass> TraitsClass;
     43 public:
     44   SymbolTableListTraits() {}
     45 
     46   /// getListOwner - Return the object that owns this list.  If this is a list
     47   /// of instructions, it returns the BasicBlock that owns them.
     48   ItemParentClass *getListOwner() {
     49     size_t Offset(size_t(&((ItemParentClass*)nullptr->*ItemParentClass::
     50                            getSublistAccess(static_cast<ValueSubClass*>(nullptr)))));
     51     iplist<ValueSubClass>* Anchor(static_cast<iplist<ValueSubClass>*>(this));
     52     return reinterpret_cast<ItemParentClass*>(reinterpret_cast<char*>(Anchor)-
     53                                               Offset);
     54   }
     55 
     56   static iplist<ValueSubClass> &getList(ItemParentClass *Par) {
     57     return Par->*(Par->getSublistAccess((ValueSubClass*)nullptr));
     58   }
     59 
     60   static ValueSymbolTable *getSymTab(ItemParentClass *Par) {
     61     return Par ? toPtr(Par->getValueSymbolTable()) : nullptr;
     62   }
     63 
     64   void addNodeToList(ValueSubClass *V);
     65   void removeNodeFromList(ValueSubClass *V);
     66   void transferNodesFromList(ilist_traits<ValueSubClass> &L2,
     67                              ilist_iterator<ValueSubClass> first,
     68                              ilist_iterator<ValueSubClass> last);
     69 //private:
     70   template<typename TPtr>
     71   void setSymTabObject(TPtr *, TPtr);
     72   static ValueSymbolTable *toPtr(ValueSymbolTable *P) { return P; }
     73   static ValueSymbolTable *toPtr(ValueSymbolTable &R) { return &R; }
     74 };
     75 
     76 } // End llvm namespace
     77 
     78 #endif
     79