1 //===- llvm/Analysis/Interval.h - Interval Class Declaration ----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains the declaration of the Interval class, which
10 // represents a set of CFG nodes and is a portion of an interval partition.
11 //
12 // Intervals have some interesting and useful properties, including the
13 // following:
14 // 1. The header node of an interval dominates all of the elements of the
15 // interval
16 //
17 //===----------------------------------------------------------------------===//
18
19 #ifndef LLVM_ANALYSIS_INTERVAL_H
20 #define LLVM_ANALYSIS_INTERVAL_H
21
22 #include "llvm/ADT/GraphTraits.h"
23 #include <vector>
24
25 namespace llvm {
26
27 class BasicBlock;
28 class raw_ostream;
29
30 //===----------------------------------------------------------------------===//
31 //
32 /// Interval Class - An Interval is a set of nodes defined such that every node
33 /// in the interval has all of its predecessors in the interval (except for the
34 /// header)
35 ///
36 class Interval {
37 /// HeaderNode - The header BasicBlock, which dominates all BasicBlocks in this
38 /// interval. Also, any loops in this interval must go through the HeaderNode.
39 ///
40 BasicBlock *HeaderNode;
41
42 public:
43 using succ_iterator = std::vector<BasicBlock*>::iterator;
44 using pred_iterator = std::vector<BasicBlock*>::iterator;
45 using node_iterator = std::vector<BasicBlock*>::iterator;
46
Interval(BasicBlock * Header)47 inline Interval(BasicBlock *Header) : HeaderNode(Header) {
48 Nodes.push_back(Header);
49 }
50
getHeaderNode()51 inline BasicBlock *getHeaderNode() const { return HeaderNode; }
52
53 /// Nodes - The basic blocks in this interval.
54 std::vector<BasicBlock*> Nodes;
55
56 /// Successors - List of BasicBlocks that are reachable directly from nodes in
57 /// this interval, but are not in the interval themselves.
58 /// These nodes necessarily must be header nodes for other intervals.
59 std::vector<BasicBlock*> Successors;
60
61 /// Predecessors - List of BasicBlocks that have this Interval's header block
62 /// as one of their successors.
63 std::vector<BasicBlock*> Predecessors;
64
65 /// contains - Find out if a basic block is in this interval
contains(BasicBlock * BB)66 inline bool contains(BasicBlock *BB) const {
67 for (BasicBlock *Node : Nodes)
68 if (Node == BB)
69 return true;
70 return false;
71 // I don't want the dependency on <algorithm>
72 //return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end();
73 }
74
75 /// isSuccessor - find out if a basic block is a successor of this Interval
isSuccessor(BasicBlock * BB)76 inline bool isSuccessor(BasicBlock *BB) const {
77 for (BasicBlock *Successor : Successors)
78 if (Successor == BB)
79 return true;
80 return false;
81 // I don't want the dependency on <algorithm>
82 //return find(Successors.begin(), Successors.end(), BB) != Successors.end();
83 }
84
85 /// Equality operator. It is only valid to compare two intervals from the
86 /// same partition, because of this, all we have to check is the header node
87 /// for equality.
88 inline bool operator==(const Interval &I) const {
89 return HeaderNode == I.HeaderNode;
90 }
91
92 /// print - Show contents in human readable format...
93 void print(raw_ostream &O) const;
94 };
95
96 /// succ_begin/succ_end - define methods so that Intervals may be used
97 /// just like BasicBlocks can with the succ_* functions, and *::succ_iterator.
98 ///
succ_begin(Interval * I)99 inline Interval::succ_iterator succ_begin(Interval *I) {
100 return I->Successors.begin();
101 }
succ_end(Interval * I)102 inline Interval::succ_iterator succ_end(Interval *I) {
103 return I->Successors.end();
104 }
105
106 /// pred_begin/pred_end - define methods so that Intervals may be used
107 /// just like BasicBlocks can with the pred_* functions, and *::pred_iterator.
108 ///
pred_begin(Interval * I)109 inline Interval::pred_iterator pred_begin(Interval *I) {
110 return I->Predecessors.begin();
111 }
pred_end(Interval * I)112 inline Interval::pred_iterator pred_end(Interval *I) {
113 return I->Predecessors.end();
114 }
115
116 template <> struct GraphTraits<Interval*> {
117 using NodeRef = Interval *;
118 using ChildIteratorType = Interval::succ_iterator;
119
120 static NodeRef getEntryNode(Interval *I) { return I; }
121
122 /// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
123 static ChildIteratorType child_begin(NodeRef N) { return succ_begin(N); }
124 static ChildIteratorType child_end(NodeRef N) { return succ_end(N); }
125 };
126
127 template <> struct GraphTraits<Inverse<Interval*>> {
128 using NodeRef = Interval *;
129 using ChildIteratorType = Interval::pred_iterator;
130
131 static NodeRef getEntryNode(Inverse<Interval *> G) { return G.Graph; }
132 static ChildIteratorType child_begin(NodeRef N) { return pred_begin(N); }
133 static ChildIteratorType child_end(NodeRef N) { return pred_end(N); }
134 };
135
136 } // end namespace llvm
137
138 #endif // LLVM_ANALYSIS_INTERVAL_H
139