include/llvm/IR/SymbolTableListTraits.h

   1 //===- llvm/SymbolTableListTraits.h - Traits for iplist ---------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file defines a generic class that is used to implement the automatic
  10 // symbol table manipulation that occurs when you put (for example) a named
  11 // instruction into a basic block.
  12 //
  13 // The way that this is implemented is by using a special traits class with the
  14 // intrusive list that makes up the list of instructions in a basic block.  When
  15 // a new element is added to the list of instructions, the traits class is
  16 // notified, allowing the symbol table to be updated.
  17 //
  18 // This generic class implements the traits class.  It must be generic so that
  19 // it can work for all uses it, which include lists of instructions, basic
  20 // blocks, arguments, functions, global variables, etc...
  21 //
  22 //===----------------------------------------------------------------------===//
  23
  24 #ifndef LLVM_IR_SYMBOLTABLELISTTRAITS_H
  25 #define LLVM_IR_SYMBOLTABLELISTTRAITS_H
  26
  27 #include "llvm/ADT/ilist.h"
  28 #include "llvm/ADT/simple_ilist.h"
  29 #include <cstddef>
  30
  31 namespace llvm {
  32
  33 class Argument;
  34 class BasicBlock;
  35 class Function;
  36 class GlobalAlias;
  37 class GlobalIFunc;
  38 class GlobalVariable;
  39 class Instruction;
  40 class Module;
  41 class ValueSymbolTable;
  42
  43 /// Template metafunction to get the parent type for a symbol table list.
  44 ///
  45 /// Implementations create a typedef called \c type so that we only need a
  46 /// single template parameter for the list and traits.
  47 template <typename NodeTy> struct SymbolTableListParentType {};
  48
  49 #define DEFINE_SYMBOL_TABLE_PARENT_TYPE(NODE, PARENT)                          \
  50   template <> struct SymbolTableListParentType<NODE> { using type = PARENT; };
  51 DEFINE_SYMBOL_TABLE_PARENT_TYPE(Instruction, BasicBlock)
  52 DEFINE_SYMBOL_TABLE_PARENT_TYPE(BasicBlock, Function)
  53 DEFINE_SYMBOL_TABLE_PARENT_TYPE(Argument, Function)
  54 DEFINE_SYMBOL_TABLE_PARENT_TYPE(Function, Module)
  55 DEFINE_SYMBOL_TABLE_PARENT_TYPE(GlobalVariable, Module)
  56 DEFINE_SYMBOL_TABLE_PARENT_TYPE(GlobalAlias, Module)
  57 DEFINE_SYMBOL_TABLE_PARENT_TYPE(GlobalIFunc, Module)
  58 #undef DEFINE_SYMBOL_TABLE_PARENT_TYPE
  59
  60 template <typename NodeTy> class SymbolTableList;
  61
  62 // ValueSubClass   - The type of objects that I hold, e.g. Instruction.
  63 // ItemParentClass - The type of object that owns the list, e.g. BasicBlock.
  64 //
  65 template <typename ValueSubClass>
  66 class SymbolTableListTraits : public ilist_alloc_traits<ValueSubClass> {
  67   using ListTy = SymbolTableList<ValueSubClass>;
  68   using iterator = typename simple_ilist<ValueSubClass>::iterator;
  69   using ItemParentClass =
  70       typename SymbolTableListParentType<ValueSubClass>::type;
  71
  72 public:
  73   SymbolTableListTraits() = default;
  74
  75 private:
  76   /// getListOwner - Return the object that owns this list.  If this is a list
  77   /// of instructions, it returns the BasicBlock that owns them.
  78   ItemParentClass *getListOwner() {
  79     size_t Offset(size_t(&((ItemParentClass*)nullptr->*ItemParentClass::
  80                            getSublistAccess(static_cast<ValueSubClass*>(nullptr)))));
  81     ListTy *Anchor(static_cast<ListTy *>(this));
  82     return reinterpret_cast<ItemParentClass*>(reinterpret_cast<char*>(Anchor)-
  83                                               Offset);
  84   }
  85
  86   static ListTy &getList(ItemParentClass *Par) {
  87     return Par->*(Par->getSublistAccess((ValueSubClass*)nullptr));
  88   }
  89
  90   static ValueSymbolTable *getSymTab(ItemParentClass *Par) {
  91     return Par ? toPtr(Par->getValueSymbolTable()) : nullptr;
  92   }
  93
  94 public:
  95   void addNodeToList(ValueSubClass *V);
  96   void removeNodeFromList(ValueSubClass *V);
  97   void transferNodesFromList(SymbolTableListTraits &L2, iterator first,
  98                              iterator last);
  99   // private:
 100   template<typename TPtr>
 101   void setSymTabObject(TPtr *, TPtr);
 102   static ValueSymbolTable *toPtr(ValueSymbolTable *P) { return P; }
 103   static ValueSymbolTable *toPtr(ValueSymbolTable &R) { return &R; }
 104 };
 105
 106 /// List that automatically updates parent links and symbol tables.
 107 ///
 108 /// When nodes are inserted into and removed from this list, the associated
 109 /// symbol table will be automatically updated.  Similarly, parent links get
 110 /// updated automatically.
 111 template <class T>
 112 class SymbolTableList
 113     : public iplist_impl<simple_ilist<T>, SymbolTableListTraits<T>> {};
 114
 115 } // end namespace llvm
 116
 117 #endif // LLVM_IR_SYMBOLTABLELISTTRAITS_H