LLVM API Documentation

Interval.h

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00001 //===- llvm/Analysis/Interval.h - Interval Class Declaration ----*- C++ -*-===//
00002 //
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 //
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file contains the declaration of the Interval class, which
00011 // represents a set of CFG nodes and is a portion of an interval partition.
00012 //
00013 // Intervals have some interesting and useful properties, including the
00014 // following:
00015 //    1. The header node of an interval dominates all of the elements of the
00016 //       interval
00017 //
00018 //===----------------------------------------------------------------------===//
00019 
00020 #ifndef LLVM_INTERVAL_H
00021 #define LLVM_INTERVAL_H
00022 
00023 #include "llvm/ADT/GraphTraits.h"
00024 #include <vector>
00025 #include <iosfwd>
00026 
00027 namespace llvm {
00028 
00029 class BasicBlock;
00030 
00031 //===----------------------------------------------------------------------===//
00032 //
00033 /// Interval Class - An Interval is a set of nodes defined such that every node
00034 /// in the interval has all of its predecessors in the interval (except for the
00035 /// header)
00036 ///
00037 class Interval {
00038   /// HeaderNode - The header BasicBlock, which dominates all BasicBlocks in this
00039   /// interval.  Also, any loops in this interval must go through the HeaderNode.
00040   ///
00041   BasicBlock *HeaderNode;
00042 public:
00043   typedef std::vector<BasicBlock*>::iterator succ_iterator;
00044   typedef std::vector<BasicBlock*>::iterator pred_iterator;
00045   typedef std::vector<BasicBlock*>::iterator node_iterator;
00046 
00047   inline Interval(BasicBlock *Header) : HeaderNode(Header) {
00048     Nodes.push_back(Header);
00049   }
00050 
00051   inline Interval(const Interval &I) // copy ctor
00052     : HeaderNode(I.HeaderNode), Nodes(I.Nodes), Successors(I.Successors) {}
00053 
00054   inline BasicBlock *getHeaderNode() const { return HeaderNode; }
00055 
00056   /// Nodes - The basic blocks in this interval.
00057   ///
00058   std::vector<BasicBlock*> Nodes;
00059 
00060   /// Successors - List of BasicBlocks that are reachable directly from nodes in
00061   /// this interval, but are not in the interval themselves.
00062   /// These nodes necessarily must be header nodes for other intervals.
00063   ///
00064   std::vector<BasicBlock*> Successors;
00065 
00066   /// Predecessors - List of BasicBlocks that have this Interval's header block
00067   /// as one of their successors.
00068   ///
00069   std::vector<BasicBlock*> Predecessors;
00070 
00071   /// contains - Find out if a basic block is in this interval
00072   inline bool contains(BasicBlock *BB) const {
00073     for (unsigned i = 0; i < Nodes.size(); ++i)
00074       if (Nodes[i] == BB) return true;
00075     return false;
00076     // I don't want the dependency on <algorithm>
00077     //return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end();
00078   }
00079 
00080   /// isSuccessor - find out if a basic block is a successor of this Interval
00081   inline bool isSuccessor(BasicBlock *BB) const {
00082     for (unsigned i = 0; i < Successors.size(); ++i)
00083       if (Successors[i] == BB) return true;
00084     return false;
00085     // I don't want the dependency on <algorithm>
00086     //return find(Successors.begin(), Successors.end(), BB) != Successors.end();
00087   }
00088 
00089   /// Equality operator.  It is only valid to compare two intervals from the
00090   /// same partition, because of this, all we have to check is the header node
00091   /// for equality.
00092   ///
00093   inline bool operator==(const Interval &I) const {
00094     return HeaderNode == I.HeaderNode;
00095   }
00096 
00097   /// isLoop - Find out if there is a back edge in this interval...
00098   bool isLoop() const;
00099 
00100   /// print - Show contents in human readable format...
00101   void print(std::ostream &O) const;
00102 };
00103 
00104 /// succ_begin/succ_end - define methods so that Intervals may be used
00105 /// just like BasicBlocks can with the succ_* functions, and *::succ_iterator.
00106 ///
00107 inline Interval::succ_iterator succ_begin(Interval *I) {
00108   return I->Successors.begin();
00109 }
00110 inline Interval::succ_iterator succ_end(Interval *I)   {
00111   return I->Successors.end();
00112 }
00113 
00114 /// pred_begin/pred_end - define methods so that Intervals may be used
00115 /// just like BasicBlocks can with the pred_* functions, and *::pred_iterator.
00116 ///
00117 inline Interval::pred_iterator pred_begin(Interval *I) {
00118   return I->Predecessors.begin();
00119 }
00120 inline Interval::pred_iterator pred_end(Interval *I)   {
00121   return I->Predecessors.end();
00122 }
00123 
00124 template <> struct GraphTraits<Interval*> {
00125   typedef Interval NodeType;
00126   typedef Interval::succ_iterator ChildIteratorType;
00127 
00128   static NodeType *getEntryNode(Interval *I) { return I; }
00129 
00130   /// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
00131   static inline ChildIteratorType child_begin(NodeType *N) {
00132     return succ_begin(N);
00133   }
00134   static inline ChildIteratorType child_end(NodeType *N) {
00135     return succ_end(N);
00136   }
00137 };
00138 
00139 template <> struct GraphTraits<Inverse<Interval*> > {
00140   typedef Interval NodeType;
00141   typedef Interval::pred_iterator ChildIteratorType;
00142   static NodeType *getEntryNode(Inverse<Interval *> G) { return G.Graph; }
00143   static inline ChildIteratorType child_begin(NodeType *N) {
00144     return pred_begin(N);
00145   }
00146   static inline ChildIteratorType child_end(NodeType *N) {
00147     return pred_end(N);
00148   }
00149 };
00150 
00151 } // End llvm namespace
00152 
00153 #endif