Interval.h revision 75517097e71f79b0a6daaa02a8c0a038436863d4 
1//===- llvm/Analysis/Interval.h - Interval Class Declaration -----*- C++ -*--=//
2//
3// This file contains the declaration of the cfg::Interval class, which
4// represents a set of CFG nodes and is a portion of an interval partition.
5//
6// Intervals have some interesting and useful properties, including the
7// following:
8//    1. The header node of an interval dominates all of the elements of the
9//       interval
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_INTERVAL_H
14#define LLVM_INTERVAL_H
15
16#include <vector>
17
18class BasicBlock;
19
20namespace cfg {
21
22//===----------------------------------------------------------------------===//
23//
24// Interval Class - An Interval is a set of nodes defined such that every node
25// in the interval has all of its predecessors in the interval (except for the
26// header)
27//
28class Interval {
29  // HeaderNode - The header BasicBlock, which dominates all BasicBlocks in this
30  // interval.  Also, any loops in this interval must go through the HeaderNode.
31  //
32  BasicBlock *HeaderNode;
33public:
34  typedef vector<BasicBlock*>::iterator succ_iterator;
35  typedef vector<BasicBlock*>::iterator pred_iterator;
36  typedef vector<BasicBlock*>::iterator node_iterator;
37
38  inline Interval(BasicBlock *Header) : HeaderNode(Header) {
39    Nodes.push_back(Header);
40  }
41
42  inline BasicBlock *getHeaderNode() const { return HeaderNode; }
43
44  // Nodes - The basic blocks in this interval.
45  //
46  vector<BasicBlock*> Nodes;
47
48  // Successors - List of BasicBlocks that are reachable directly from nodes in
49  // this interval, but are not in the interval themselves.
50  // These nodes neccesarily must be header nodes for other intervals.
51  //
52  vector<BasicBlock*> Successors;
53
54  // Predecessors - List of BasicBlocks that have this Interval's header block
55  // as one of their successors.
56  //
57  vector<BasicBlock*> Predecessors;
58
59  // contains - Find out if a basic block is in this interval
60  inline bool contains(BasicBlock *BB) const {
61    for (unsigned i = 0; i < Nodes.size(); ++i)
62      if (Nodes[i] == BB) return true;
63    return false;
64    // I don't want the dependency on <algorithm>
65    //return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end();
66  }
67
68  // isSuccessor - find out if a basic block is a successor of this Interval
69  inline bool isSuccessor(BasicBlock *BB) const {
70    for (unsigned i = 0; i < Successors.size(); ++i)
71      if (Successors[i] == BB) return true;
72    return false;
73    // I don't want the dependency on <algorithm>
74    //return find(Successors.begin(), Successors.end(), BB) != Successors.end();
75  }
76
77  // isLoop - Find out if there is a back edge in this interval...
78  bool isLoop() const;
79};
80
81
82// succ_begin/succ_end - define global functions so that Intervals may be used
83// just like BasicBlocks can with the succ_* functions, and *::succ_iterator.
84//
85inline Interval::succ_iterator succ_begin(Interval *I) {
86  return I->Successors.begin();
87}
88inline Interval::succ_iterator succ_end(Interval *I) {
89  return I->Successors.end();
90}
91
92// pred_begin/pred_end - define global functions so that Intervals may be used
93// just like BasicBlocks can with the pred_* functions, and *::pred_iterator.
94//
95inline Interval::pred_iterator pred_begin(Interval *I) {
96  return I->Predecessors.begin();
97}
98inline Interval::pred_iterator pred_end(Interval *I) {
99  return I->Predecessors.end();
100}
101
102}    // End namespace cfg
103
104#endif
105