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
26 namespace llvm {
27
28 class BasicBlock;
29 class 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 ///
37 class 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;
42 public:
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
Interval(BasicBlock * Header)47 inline Interval(BasicBlock *Header) : HeaderNode(Header) {
48 Nodes.push_back(Header);
49 }
50
Interval(const Interval & I)51 inline Interval(const Interval &I) // copy ctor
52 : HeaderNode(I.HeaderNode), Nodes(I.Nodes), Successors(I.Successors) {}
53
getHeaderNode()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
contains(BasicBlock * BB)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
isSuccessor(BasicBlock * BB)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 ///
succ_begin(Interval * I)107 inline Interval::succ_iterator succ_begin(Interval *I) {
108 return I->Successors.begin();
109 }
succ_end(Interval * I)110 inline 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 ///
pred_begin(Interval * I)117 inline Interval::pred_iterator pred_begin(Interval *I) {
118 return I->Predecessors.begin();
119 }
pred_end(Interval * I)120 inline Interval::pred_iterator pred_end(Interval *I) {
121 return I->Predecessors.end();
122 }
123
124 template <> 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
139 template <> 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