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      1 //===-- llvm/Support/DataFlow.h - dataflow as graphs ------------*- 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 specializations of GraphTraits that allows Use-Def and
     11 // Def-Use relations to be treated as proper graphs for generic algorithms.
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_SUPPORT_DATAFLOW_H
     15 #define LLVM_SUPPORT_DATAFLOW_H
     16 
     17 #include "llvm/User.h"
     18 #include "llvm/ADT/GraphTraits.h"
     19 
     20 namespace llvm {
     21 
     22 //===----------------------------------------------------------------------===//
     23 // Provide specializations of GraphTraits to be able to treat def-use/use-def
     24 // chains as graphs
     25 
     26 template <> struct GraphTraits<const Value*> {
     27   typedef const Value NodeType;
     28   typedef Value::const_use_iterator ChildIteratorType;
     29 
     30   static NodeType *getEntryNode(const Value *G) {
     31     return G;
     32   }
     33 
     34   static inline ChildIteratorType child_begin(NodeType *N) {
     35     return N->use_begin();
     36   }
     37 
     38   static inline ChildIteratorType child_end(NodeType *N) {
     39     return N->use_end();
     40   }
     41 };
     42 
     43 template <> struct GraphTraits<Value*> {
     44   typedef Value NodeType;
     45   typedef Value::use_iterator ChildIteratorType;
     46 
     47   static NodeType *getEntryNode(Value *G) {
     48     return G;
     49   }
     50 
     51   static inline ChildIteratorType child_begin(NodeType *N) {
     52     return N->use_begin();
     53   }
     54 
     55   static inline ChildIteratorType child_end(NodeType *N) {
     56     return N->use_end();
     57   }
     58 };
     59 
     60 template <> struct GraphTraits<Inverse<const User*> > {
     61   typedef const Value NodeType;
     62   typedef User::const_op_iterator ChildIteratorType;
     63 
     64   static NodeType *getEntryNode(Inverse<const User*> G) {
     65     return G.Graph;
     66   }
     67 
     68   static inline ChildIteratorType child_begin(NodeType *N) {
     69     if (const User *U = dyn_cast<User>(N))
     70       return U->op_begin();
     71     return NULL;
     72   }
     73 
     74   static inline ChildIteratorType child_end(NodeType *N) {
     75     if(const User *U = dyn_cast<User>(N))
     76       return U->op_end();
     77     return NULL;
     78   }
     79 };
     80 
     81 template <> struct GraphTraits<Inverse<User*> > {
     82   typedef Value NodeType;
     83   typedef User::op_iterator ChildIteratorType;
     84 
     85   static NodeType *getEntryNode(Inverse<User*> G) {
     86     return G.Graph;
     87   }
     88 
     89   static inline ChildIteratorType child_begin(NodeType *N) {
     90     if (User *U = dyn_cast<User>(N))
     91       return U->op_begin();
     92     return NULL;
     93   }
     94 
     95   static inline ChildIteratorType child_end(NodeType *N) {
     96     if (User *U = dyn_cast<User>(N))
     97       return U->op_end();
     98     return NULL;
     99   }
    100 };
    101 
    102 }
    103 #endif
    104