Interval.h revision 45cfe545ec8177262dabc70580ce05feaa1c3880 
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
26namespace llvm {
27
28class BasicBlock;
29class raw_ostream;
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(raw_ostream &O) const;
102};
103
104/// succ_begin/succ_end - define methods so that Intervals may be used
105/// just like BasicBlocks can with the succ_* functions, and *::succ_iterator.
106///
107inline Interval::succ_iterator succ_begin(Interval *I) {
108  return I->Successors.begin();
109}
110inline Interval::succ_iterator succ_end(Interval *I)   {
111  return I->Successors.end();
112}
113
114/// pred_begin/pred_end - define methods so that Intervals may be used
115/// just like BasicBlocks can with the pred_* functions, and *::pred_iterator.
116///
117inline Interval::pred_iterator pred_begin(Interval *I) {
118  return I->Predecessors.begin();
119}
120inline Interval::pred_iterator pred_end(Interval *I)   {
121  return I->Predecessors.end();
122}
123
124template <> struct GraphTraits<Interval*> {
125  typedef Interval NodeType;
126  typedef Interval::succ_iterator ChildIteratorType;
127
128  static NodeType *getEntryNode(Interval *I) { return I; }
129
130  /// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
131  static inline ChildIteratorType child_begin(NodeType *N) {
132    return succ_begin(N);
133  }
134  static inline ChildIteratorType child_end(NodeType *N) {
135    return succ_end(N);
136  }
137};
138
139template <> struct GraphTraits<Inverse<Interval*> > {
140  typedef Interval NodeType;
141  typedef Interval::pred_iterator ChildIteratorType;
142  static NodeType *getEntryNode(Inverse<Interval *> G) { return G.Graph; }
143  static inline ChildIteratorType child_begin(NodeType *N) {
144    return pred_begin(N);
145  }
146  static inline ChildIteratorType child_end(NodeType *N) {
147    return pred_end(N);
148  }
149};
150
151} // End llvm namespace
152
153#endif
154