gcc/digraph.cc

   1 /* Template classes for directed graphs.
   2    Copyright (C) 2019-2021 Free Software Foundation, Inc.
   3    Contributed by David Malcolm <dmalcolm@redhat.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it
   8 under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "diagnostic.h"
  25 #include "graphviz.h"
  26 #include "digraph.h"
  27 #include "shortest-paths.h"
  28 #include "selftest.h"
  29
  30 #if CHECKING_P
  31
  32 namespace selftest {
  33
  34 /* A family of digraph classes for writing selftests.  */
  35
  36 struct test_node;
  37 struct test_edge;
  38 struct test_graph;
  39 struct test_dump_args_t {};
  40 struct test_cluster;
  41
  42 struct test_graph_traits
  43 {
  44   typedef test_node node_t;
  45   typedef test_edge edge_t;
  46   typedef test_graph graph_t;
  47   typedef test_dump_args_t dump_args_t;
  48   typedef test_cluster cluster_t;
  49 };
  50
  51 struct test_node : public dnode<test_graph_traits>
  52 {
  53   test_node (const char *name, int index) : m_name (name), m_index (index) {}
  54   void dump_dot (graphviz_out *, const dump_args_t &) const OVERRIDE
  55   {
  56   }
  57
  58   const char *m_name;
  59   int m_index;
  60 };
  61
  62 struct test_edge : public dedge<test_graph_traits>
  63 {
  64   test_edge (node_t *src, node_t *dest)
  65   : dedge<test_graph_traits> (src, dest)
  66   {}
  67
  68   void dump_dot (graphviz_out *gv, const dump_args_t &) const OVERRIDE
  69   {
  70     gv->println ("%s %s %s%c", m_src->m_name, "->", m_dest->m_name, ';');
  71   }
  72 };
  73
  74 struct test_graph : public digraph<test_graph_traits>
  75 {
  76   test_node *add_test_node (const char *name)
  77   {
  78     test_node *result = new test_node (name, m_nodes.length ());
  79     add_node (result);
  80     return result;
  81   }
  82
  83   test_edge *add_test_edge (test_node *src, test_node *dst)
  84   {
  85     test_edge *result = new test_edge (src, dst);
  86     add_edge (result);
  87     return result;
  88   }
  89 };
  90
  91 struct test_cluster : public cluster<test_graph_traits>
  92 {
  93 };
  94
  95 struct test_path
  96 {
  97   auto_vec<const test_edge *> m_edges;
  98 };
  99
 100 /* Smoketest of digraph dumping.  */
 101
 102 static void
 103 test_dump_to_dot ()
 104 {
 105   test_graph g;
 106   test_node *a = g.add_test_node ("a");
 107   test_node *b = g.add_test_node ("b");
 108   g.add_test_edge (a, b);
 109
 110   pretty_printer pp;
 111   pp.buffer->stream = NULL;
 112   test_dump_args_t dump_args;
 113   g.dump_dot_to_pp (&pp, NULL, dump_args);
 114
 115   ASSERT_STR_CONTAINS (pp_formatted_text (&pp),
 116                        "a -> b;\n");
 117 }
 118
 119 /* Test shortest paths from A in this digraph,
 120    where edges run top-to-bottom if not otherwise labeled:
 121
 122       A
 123      / \
 124     B   C-->D
 125     |   |
 126     E   |
 127      \ /
 128       F.  */
 129
 130 static void
 131 test_shortest_paths ()
 132 {
 133   test_graph g;
 134   test_node *a = g.add_test_node ("a");
 135   test_node *b = g.add_test_node ("b");
 136   test_node *c = g.add_test_node ("d");
 137   test_node *d = g.add_test_node ("d");
 138   test_node *e = g.add_test_node ("e");
 139   test_node *f = g.add_test_node ("f");
 140
 141   test_edge *ab = g.add_test_edge (a, b);
 142   test_edge *ac = g.add_test_edge (a, c);
 143   test_edge *cd = g.add_test_edge (c, d);
 144   test_edge *be = g.add_test_edge (b, e);
 145   test_edge *ef = g.add_test_edge (e, f);
 146   test_edge *cf = g.add_test_edge (c, f);
 147
 148   /* Use "A" as the origin; all nodes should be reachable.  */
 149   {
 150     shortest_paths<test_graph_traits, test_path> sp (g, a);
 151
 152     test_path path_to_a = sp.get_shortest_path (a);
 153     ASSERT_EQ (path_to_a.m_edges.length (), 0); /* Trivial path.  */
 154
 155     test_path path_to_b = sp.get_shortest_path (b);
 156     ASSERT_EQ (path_to_b.m_edges.length (), 1);
 157     ASSERT_EQ (path_to_b.m_edges[0], ab);
 158
 159     test_path path_to_c = sp.get_shortest_path (c);
 160     ASSERT_EQ (path_to_c.m_edges.length (), 1);
 161     ASSERT_EQ (path_to_c.m_edges[0], ac);
 162
 163     test_path path_to_d = sp.get_shortest_path (d);
 164     ASSERT_EQ (path_to_d.m_edges.length (), 2);
 165     ASSERT_EQ (path_to_d.m_edges[0], ac);
 166     ASSERT_EQ (path_to_d.m_edges[1], cd);
 167
 168     test_path path_to_e = sp.get_shortest_path (e);
 169     ASSERT_EQ (path_to_e.m_edges.length (), 2);
 170     ASSERT_EQ (path_to_e.m_edges[0], ab);
 171     ASSERT_EQ (path_to_e.m_edges[1], be);
 172
 173     test_path path_to_f = sp.get_shortest_path (f);
 174     ASSERT_EQ (path_to_f.m_edges.length (), 2);
 175     ASSERT_EQ (path_to_f.m_edges[0], ac);
 176     ASSERT_EQ (path_to_f.m_edges[1], cf);
 177   }
 178
 179   /* Verify that we gracefully handle an origin from which some nodes
 180      aren't reachable.  */
 181
 182   /* Use "B" as the origin, so only E and F are reachable.  */
 183   {
 184     shortest_paths<test_graph_traits, test_path> sp (g, b);
 185
 186     test_path path_to_a = sp.get_shortest_path (a);
 187     ASSERT_EQ (path_to_a.m_edges.length (), 0); /* No path.  */
 188
 189     test_path path_to_b = sp.get_shortest_path (b);
 190     ASSERT_EQ (path_to_b.m_edges.length (), 0); /* Trivial path.  */
 191
 192     test_path path_to_c = sp.get_shortest_path (c);
 193     ASSERT_EQ (path_to_c.m_edges.length (), 0); /* No path.  */
 194
 195     test_path path_to_d = sp.get_shortest_path (d);
 196     ASSERT_EQ (path_to_d.m_edges.length (), 0); /* No path.  */
 197
 198     test_path path_to_e = sp.get_shortest_path (e);
 199     ASSERT_EQ (path_to_e.m_edges.length (), 1);
 200     ASSERT_EQ (path_to_e.m_edges[0], be);
 201
 202     test_path path_to_f = sp.get_shortest_path (f);
 203     ASSERT_EQ (path_to_f.m_edges.length (), 2);
 204     ASSERT_EQ (path_to_f.m_edges[0], be);
 205     ASSERT_EQ (path_to_f.m_edges[1], ef);
 206   }
 207
 208   /* Use "C" as the origin, so only D and F are reachable.  */
 209   {
 210     shortest_paths<test_graph_traits, test_path> sp (g, c);
 211
 212     test_path path_to_a = sp.get_shortest_path (a);
 213     ASSERT_EQ (path_to_a.m_edges.length (), 0); /* No path.  */
 214
 215     test_path path_to_b = sp.get_shortest_path (b);
 216     ASSERT_EQ (path_to_b.m_edges.length (), 0); /* No path.  */
 217
 218     test_path path_to_c = sp.get_shortest_path (c);
 219     ASSERT_EQ (path_to_c.m_edges.length (), 0); /* Trivial path.  */
 220
 221     test_path path_to_d = sp.get_shortest_path (d);
 222     ASSERT_EQ (path_to_d.m_edges.length (), 1);
 223     ASSERT_EQ (path_to_d.m_edges[0], cd);
 224
 225     test_path path_to_e = sp.get_shortest_path (e);
 226     ASSERT_EQ (path_to_e.m_edges.length (), 0); /* No path.  */
 227
 228     test_path path_to_f = sp.get_shortest_path (f);
 229     ASSERT_EQ (path_to_f.m_edges.length (), 1);
 230     ASSERT_EQ (path_to_f.m_edges[0], cf);
 231   }
 232 }
 233
 234 /* Run all of the selftests within this file.  */
 235
 236 void
 237 digraph_cc_tests ()
 238 {
 239   test_dump_to_dot ();
 240   test_shortest_paths ();
 241 }
 242
 243 } // namespace selftest
 244
 245 #endif /* #if CHECKING_P */