Interval.h revision 7ed47a13356daed2a34cd2209a31f92552e3bdd8 
1//===- llvm/Analysis/Interval.h - Interval Class Declaration ----*- 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 contains the declaration of the Interval class, which
11// represents a set of CFG nodes and is a portion of an interval partition.
12//
13// Intervals have some interesting and useful properties, including the
14// following:
15//    1. The header node of an interval dominates all of the elements of the
16//       interval
17//
18//===----------------------------------------------------------------------===//
19
20#ifndef LLVM_INTERVAL_H
21#define LLVM_INTERVAL_H
22
23#include "llvm/ADT/GraphTraits.h"
24#include <vector>
25#include <iosfwd>
26
27namespace llvm {
28
29class BasicBlock;
30
31//===----------------------------------------------------------------------===//
32//
33/// Interval Class - An Interval is a set of nodes defined such that every node
34/// in the interval has all of its predecessors in the interval (except for the
35/// header)
36///
37class Interval {
38  /// HeaderNode - The header BasicBlock, which dominates all BasicBlocks in this
39  /// interval.  Also, any loops in this interval must go through the HeaderNode.
40  ///
41  BasicBlock *HeaderNode;
42public:
43  typedef std::vector<BasicBlock*>::iterator succ_iterator;
44  typedef std::vector<BasicBlock*>::iterator pred_iterator;
45  typedef std::vector<BasicBlock*>::iterator node_iterator;
46
47  inline Interval(BasicBlock *Header) : HeaderNode(Header) {
48    Nodes.push_back(Header);
49  }
50
51  inline Interval(const Interval &I) // copy ctor
52    : HeaderNode(I.HeaderNode), Nodes(I.Nodes), Successors(I.Successors) {}
53
54  inline BasicBlock *getHeaderNode() const { return HeaderNode; }
55
56  /// Nodes - The basic blocks in this interval.
57  ///
58  std::vector<BasicBlock*> Nodes;
59
60  /// Successors - List of BasicBlocks that are reachable directly from nodes in
61  /// this interval, but are not in the interval themselves.
62  /// These nodes necessarily must be header nodes for other intervals.
63  ///
64  std::vector<BasicBlock*> Successors;
65
66  /// Predecessors - List of BasicBlocks that have this Interval's header block
67  /// as one of their successors.
68  ///
69  std::vector<BasicBlock*> Predecessors;
70
71  /// contains - Find out if a basic block is in this interval
72  inline bool contains(BasicBlock *BB) const {
73    for (unsigned i = 0; i < Nodes.size(); ++i)
74      if (Nodes[i] == BB) return true;
75    return false;
76    // I don't want the dependency on <algorithm>
77    //return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end();
78  }
79
80  /// isSuccessor - find out if a basic block is a successor of this Interval
81  inline bool isSuccessor(BasicBlock *BB) const {
82    for (unsigned i = 0; i < Successors.size(); ++i)
83      if (Successors[i] == BB) return true;
84    return false;
85    // I don't want the dependency on <algorithm>
86    //return find(Successors.begin(), Successors.end(), BB) != Successors.end();
87  }
88
89  /// Equality operator.  It is only valid to compare two intervals from the
90  /// same partition, because of this, all we have to check is the header node
91  /// for equality.
92  ///
93  inline bool operator==(const Interval &I) const {
94    return HeaderNode == I.HeaderNode;
95  }
96
97  /// isLoop - Find out if there is a back edge in this interval...
98  bool isLoop() const;
99
100  /// print - Show contents in human readable format...
101  void print(std::ostream &O) const;
102  void print(std::ostream *O) const { if (O) print(*O); }
103};
104
105/// succ_begin/succ_end - define methods so that Intervals may be used
106/// just like BasicBlocks can with the succ_* functions, and *::succ_iterator.
107///
108inline Interval::succ_iterator succ_begin(Interval *I) {
109  return I->Successors.begin();
110}
111inline Interval::succ_iterator succ_end(Interval *I)   {
112  return I->Successors.end();
113}
114
115/// pred_begin/pred_end - define methods so that Intervals may be used
116/// just like BasicBlocks can with the pred_* functions, and *::pred_iterator.
117///
118inline Interval::pred_iterator pred_begin(Interval *I) {
119  return I->Predecessors.begin();
120}
121inline Interval::pred_iterator pred_end(Interval *I)   {
122  return I->Predecessors.end();
123}
124
125template <> struct GraphTraits<Interval*> {
126  typedef Interval NodeType;
127  typedef Interval::succ_iterator ChildIteratorType;
128
129  static NodeType *getEntryNode(Interval *I) { return I; }
130
131  /// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
132  static inline ChildIteratorType child_begin(NodeType *N) {
133    return succ_begin(N);
134  }
135  static inline ChildIteratorType child_end(NodeType *N) {
136    return succ_end(N);
137  }
138};
139
140template <> struct GraphTraits<Inverse<Interval*> > {
141  typedef Interval NodeType;
142  typedef Interval::pred_iterator ChildIteratorType;
143  static NodeType *getEntryNode(Inverse<Interval *> G) { return G.Graph; }
144  static inline ChildIteratorType child_begin(NodeType *N) {
145    return pred_begin(N);
146  }
147  static inline ChildIteratorType child_end(NodeType *N) {
148    return pred_end(N);
149  }
150};
151
152} // End llvm namespace
153
154#endif
155