1/*
2 * Copyright 2011 Christoph Bumiller
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
18 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
19 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 * SOFTWARE.
21 */
22
23#ifndef __NV50_IR_GRAPH_H__
24#define __NV50_IR_GRAPH_H__
25
26#include "nv50_ir_util.h"
27#include <vector>
28
29namespace nv50_ir {
30
31#define ITER_NODE(x) reinterpret_cast<Graph::Node *>((x).get())
32#define ITER_EDGE(x) reinterpret_cast<Graph::Edge *>((x).get())
33
34// A connected graph.
35class Graph
36{
37public:
38   class Node;
39
40   class Edge
41   {
42   public:
43      enum Type
44      {
45         UNKNOWN,
46         TREE,
47         FORWARD,
48         BACK,
49         CROSS, // e.g. loop break
50         DUMMY
51      };
52
53      Edge(Node *dst, Node *src, Type kind);
54      ~Edge() { unlink(); }
55
56      inline Node *getOrigin() const { return origin; }
57      inline Node *getTarget() const { return target; }
58
59      inline Type getType() const { return type; }
60      const char *typeStr() const;
61
62   private:
63      Node *origin;
64      Node *target;
65
66      Type type;
67      Edge *next[2]; // next edge outgoing/incident from/to origin/target
68      Edge *prev[2];
69
70      void unlink();
71
72      friend class Graph;
73   };
74
75   class EdgeIterator : public Iterator
76   {
77   public:
78      EdgeIterator() : e(0), t(0), d(0), rev(false) { }
79      EdgeIterator(Graph::Edge *first, int dir, bool reverse)
80         : d(dir), rev(reverse)
81      {
82         t = e = ((rev && first) ? first->prev[d] : first);
83      }
84
85      virtual void next()
86      {
87         Graph::Edge *n = (rev ? e->prev[d] : e->next[d]);
88         e = (n == t ? NULL : n);
89      }
90      virtual bool end() const { return !e; }
91      virtual void *get() const { return e; }
92
93      inline Node *getNode() const { assert(e); return d ?
94                                                   e->origin : e->target; }
95      inline Edge *getEdge() const { return e; }
96      inline Edge::Type getType() { return e ? e->getType() : Edge::UNKNOWN; }
97
98   private:
99      Graph::Edge *e;
100      Graph::Edge *t;
101      int d;
102      bool rev;
103   };
104
105   class Node
106   {
107   public:
108      Node(void *);
109      ~Node() { cut(); }
110
111      void attach(Node *, Edge::Type);
112      bool detach(Node *);
113      void cut();
114
115      inline EdgeIterator outgoing(bool reverse = false) const;
116      inline EdgeIterator incident(bool reverse = false) const;
117
118      inline Node *parent() const; // returns NULL if count(incident edges) != 1
119
120      bool reachableBy(const Node *node, const Node *term) const;
121
122      inline bool visit(int);
123      inline int  getSequence() const;
124
125      inline int incidentCountFwd() const; // count of incident non-back edges
126      inline int incidentCount() const { return inCount; }
127      inline int outgoingCount() const { return outCount; }
128
129      Graph *getGraph() const { return graph; }
130
131      void *data;
132
133   private:
134      Edge *in;
135      Edge *out;
136      Graph *graph;
137
138      int visited;
139
140      int16_t inCount;
141      int16_t outCount;
142   public:
143      int tag; // for temporary use
144
145      friend class Graph;
146   };
147
148public:
149   Graph();
150   ~Graph(); // does *not* free the nodes (make it an option ?)
151
152   inline Node *getRoot() const { return root; }
153
154   inline unsigned int getSize() const { return size; }
155
156   inline int nextSequence();
157
158   void insert(Node *node); // attach to or set as root
159
160   IteratorRef iteratorDFS(bool preorder = true);
161   IteratorRef iteratorCFG();
162
163   // safe iterators are unaffected by changes to the *edges* of the graph
164   IteratorRef safeIteratorDFS(bool preorder = true);
165   IteratorRef safeIteratorCFG();
166
167   void classifyEdges();
168
169   // @weights: indexed by Node::tag
170   int findLightestPathWeight(Node *, Node *, const std::vector<int>& weights);
171
172private:
173   void classifyDFS(Node *, int&);
174
175private:
176   Node *root;
177   unsigned int size;
178   int sequence;
179};
180
181int Graph::nextSequence()
182{
183   return ++sequence;
184}
185
186Graph::Node *Graph::Node::parent() const
187{
188   if (inCount != 1)
189      return NULL;
190   assert(in);
191   return in->origin;
192}
193
194bool Graph::Node::visit(int v)
195{
196   if (visited == v)
197      return false;
198   visited = v;
199   return true;
200}
201
202int Graph::Node::getSequence() const
203{
204   return visited;
205}
206
207Graph::EdgeIterator Graph::Node::outgoing(bool reverse) const
208{
209   return EdgeIterator(out, 0, reverse);
210}
211
212Graph::EdgeIterator Graph::Node::incident(bool reverse) const
213{
214   return EdgeIterator(in, 1, reverse);
215}
216
217int Graph::Node::incidentCountFwd() const
218{
219   int n = 0;
220   for (EdgeIterator ei = incident(); !ei.end(); ei.next())
221      if (ei.getType() != Edge::BACK)
222         ++n;
223   return n;
224}
225
226} // namespace nv50_ir
227
228#endif // __NV50_IR_GRAPH_H__
229