1 /* Copyright (c) 2002 by Universität Karlsruhe (TH). All Rights Reserved */
3 * Time-stamp: <Thursday, 31.10.2002, 16:03:00 goetz@i44pc2.info.uni-karlsruhe.de>
10 provide some auxilliary structures for firm graphs.
14 liekweg - Feb 26, 2002: Created.
25 # endif /* def DEBUG_libfirm */
30 static dtree_t *trees = 0;
32 static dtree_t *last = 0;
35 /* --------------------------------------------------------------------
37 * -------------------------------------------------------------------- */
39 Helper function for get_n_blocks
41 static void count_block (ir_node *block, void *env)
46 assert (block && "no block");
47 assert (env && "no env");
48 # endif /* def DEBUG_libfirm */
50 fprintf (stdout, "%s: Block(%p) has # (%i)\n",
51 __FILE__ ":count_block", block, *n);
57 Count the number of blocks in the given graph
59 static int get_n_blocks (ir_graph *graph)
63 ir_node *end_block = get_irg_end (graph);
66 assert (graph && "no graph");
67 assert (end_block && "no end block");
68 # endif /* def DEBUG_libfirm */
70 irg_block_walk (end_block, count_block, NULL, &n);
72 fprintf (stdout, "%s: Graph(%p) has (%i) blocks\n",
73 __FILE__ ":get_n_blocks", graph, n);
79 Build an empty dominator relation entry
81 static dtree_t *new_dtree (dt_t *tree, ir_graph *graph)
83 dtree_t *res = (dtree_t*) malloc (sizeof (dtree_t));
86 assert (res && "no memory for dtree");
87 # endif /* def DEBUG_libfirm */
97 Build an empty dominator relation
99 static dt_t *new_dt (ir_graph *graph)
101 int n_blocks = get_n_blocks (graph);
103 dt_t *res = (dt_t*) malloc (sizeof (dt_t));
105 # ifdef DEBUG_libfirm
106 assert (n_blocks && "no blocks for dt");
107 assert (res && "no memory for dt");
108 # endif /* def DEBUG_libfirm */
110 res->n_blocks = n_blocks;
112 res->blocks = (ir_node**) calloc (n_blocks, sizeof (ir_node*));
113 res->idoms = (ir_node**) calloc (n_blocks, sizeof (ir_node*));
114 res->masks = (bs_t*) calloc (n_blocks, sizeof (bs_t));
116 assert (res && "no dt");
121 static void free_dt (dt_t *dt)
123 free (dt->blocks); dt->blocks = 0;
124 free (dt->masks); dt->masks = 0;
129 /* --------------------------------------------------------------------
131 * -------------------------------------------------------------------- */
134 Given a graph, find its dominator tree in the global list:
136 @return The tree, if it exists, and 0 else
138 static dt_t *get_dominator_tree (ir_graph *graph)
140 dtree_t *iter = trees;
142 # ifdef DEBUG_libfirm
143 assert (graph && "no graph");
144 # endif /* def DEBUG_libfirm */
146 while ((0 != iter) && (graph != iter->graph))
151 # ifdef DEBUG_libfirm
152 assert ((graph == iter->tree->graph) && "wrong graph");
153 # endif /* def DEBUG_libfirm */
164 Given a dominator tree and a graph, enter the tree into the global list.
166 static void add_dominator_tree (dt_t *tree)
169 ir_graph *graph = tree->graph;
171 # ifdef DEBUG_libfirm
172 assert (tree && "no tree" );
173 assert (graph && "no graph");
174 # endif /* def DEBUG_libfirm */
176 dtree = new_dtree (tree, graph);
178 # ifdef VERBOSE_libfirm
179 fprintf (stdout, "%s: Adding dtree(%p) into trees(%p)\n",
180 __FILE__ ":" __PRETTY_FUNCTION__, dtree, trees);
181 # endif /* def VERBOSE_libfirm */
183 /* enter in global list: */
189 Get (or create) the index for a given block
191 static int get_index (dt_t *dt, ir_node *block)
195 # ifdef DEBUG_libfirm
196 assert (dt && "no dt");
197 assert (block && "no block");
198 # endif /* def DEBUG_libfirm */
200 for (i = 0; (i < dt->n_blocks) && (0 != dt->blocks [i]); i ++)
201 if (block == dt->blocks [i])
204 /* not found . . . enter new one: */
205 dt->blocks [i] = block;
206 if (block == get_irg_start_block (dt->graph))
208 dt->masks [i] = 0x00000001 << i;
210 # ifdef VERBOSE_libfirm
211 fprintf (stdout, "%s: Adding block(%p)[%i] with [%#010lx]\n",
212 __FILE__ ":" __PRETTY_FUNCTION__, block, i, dt->masks [i]);
213 # endif /* def VERBOSE_libfirm */
217 dt->masks [i] = ~0x00000000;
219 # ifdef VERBOSE_libfirm
220 fprintf (stdout, "%s: Adding block(%p)[%i] with [%#010lx]\n",
221 __FILE__ ":" __PRETTY_FUNCTION__, block, i, dt->masks [i]);
222 # endif /* def VERBOSE_libfirm */
229 Get the bit mask for a block
231 static bs_t _get_mask (dt_t*, int);
232 static bs_t get_mask (dt_t *dt, ir_node *block)
234 int index = get_index (dt, block);
236 # ifdef DEBUG_libfirm
237 assert (dt && "no dt");
238 assert (block && "no block");
239 # endif /* def DEBUG_libfirm */
241 return (_get_mask (dt, index));
245 Get the bit mask for a block index
247 static bs_t _get_mask (dt_t *dt, int index)
249 # ifdef DEBUG_libfirm
250 assert (dt && "no dt");
251 # endif /* def DEBUG_libfirm */
253 return (dt->masks [index]);
257 Set the bit mask for a block
260 static void _set_mask (dt_t*, int, bs_t);
261 static void set_mask (dt_t *dt, ir_node *block, bs_t mask)
263 int index = get_index (dt, block);
265 # ifdef DEBUG_libfirm
266 assert (dt && "no dt");
267 assert (block && "no block");
268 # endif /* def DEBUG_libfirm */
270 _set_mask (dt, index, mask);
274 Set the bit mask for a block index
276 static void _set_mask (dt_t *dt, int index, bs_t mask)
278 # ifdef DEBUG_libfirm
279 assert (dt && "no dt");
280 # endif /* def DEBUG_libfirm */
282 dt->masks [index] = mask;
286 Update the list of dominators of a given block
288 typedef struct dt_walk_env_t
290 dt_t *dt; /* the dominator relation we're building */
291 ir_node *start_block; /* need to know the start block of this graph */
292 bool changed; /* wether the relation has changed recently */
297 Helper function for build_dominator_tree
299 static void update_dominators (ir_node *block, void *env)
302 dt_walk_env_t *w = (dt_walk_env_t*) env;
305 int block_index = get_index (dt, block);
306 int n_ins = get_irn_arity (block);
308 bs_t old_mask = _get_mask (dt, block_index);
309 bs_t new_mask = ~0x00000000;
311 /* Special handling of Start Block: */
312 if (block == w->start_block)
316 for (i = 0; i < n_ins; i ++)
318 ir_node *in = get_nodes_Block (get_irn_n (block, i));
319 bs_t in_mask = get_mask (dt, in);
324 /* and remember ourselves: */
325 new_mask |= (0x00000001 << block_index);
327 if (new_mask != old_mask)
330 _set_mask (dt, block_index, new_mask);
332 # ifdef VERBOSE_libfirm
333 fprintf (stdout, "%s: Updating block(%p)[%i] from [%#010lx] to [%#010lx]\n",
334 __FILE__ ":" __PRETTY_FUNCTION__,
335 block, block_index, old_mask, new_mask);
336 # endif /* def VERBOSE_libfirm */
341 Say wether a dominates b
344 static bool _dominates (dt_t *dt, ir_node *a, ir_node *b)
346 int index_a = get_index (dt, a);
347 bs_t b_mask = get_mask (dt, b);
349 return (0 != (b_mask & (0x00000001 << index_a)));
353 Return the immediate dominator of block a
355 static ir_node *_get_idom (dt_t *dt, ir_node *block)
358 int block_index = get_index (dt, block);
360 if (0 != (idom = dt->idoms [block_index]))
363 /* check all CFG preds:
364 Question: Shouldn't it be good enough to just ask our first CFG
368 int n = get_irn_arity (block);
371 idom = block; /* prime the loop: */
373 for (i = 0; i < n; i ++)
377 pred = get_nodes_Block (get_irn_n (block, i));
378 ndom = _get_idom (dt, pred);
381 if (_dominates (dt, idom, ndom))
386 assert (idom && "Something terribly wrong in _get_idom");
388 # ifdef VERBOSE_libfirm
389 fprintf (stdout, "%s: idom(%p) = %p\n",
390 __FILE__ ":" __PRETTY_FUNCTION__,
392 # endif /* def VERBOSE_libfirm */
395 dt->idoms [block_index] = idom;
400 /* --------------------------------------------------------------------
402 * -------------------------------------------------------------------- */
405 Say wether a dominates b
407 bool dominates (ir_graph *g, ir_node *a, ir_node *b)
409 dt_t *dt = get_dominator_tree (g);
411 return (_dominates (dt, a, b));
415 Return the immediate dominator of block a
417 ir_node *get_idom (ir_graph *g, ir_node *a)
419 dt_t *dt = get_dominator_tree (g);
421 return (_get_idom (dt, a));
425 Allow for precomputation of necessary data
426 This will allow for a slightly faster lookup of the dominator
427 relation if one node is checked for dominance against many other nodes.
429 dom_env_t *get_dom_env (ir_graph *graph, ir_node *a)
431 dom_env_t *env = (dom_env_t*) calloc (1, sizeof (dom_env_t));
434 env->dt = get_dominator_tree (graph);
436 env->index_a = get_index (env->dt, a);
441 Dispose a dominator environment
443 void delete_dom_env (dom_env_t *env)
454 Say wether the node in env dominates b
458 bool dominates_l (dom_env_t *env, ir_node *b)
460 int index_a = env->index_a;
462 bs_t b_mask = get_mask (dt, b);
464 return (0 != (b_mask & (0x00000001 << index_a)));
468 Build a new dominator tree for the given graph
470 void build_dominator_tree (ir_graph *graph)
473 dt_walk_env_t *w = (dt_walk_env_t*) alloca (sizeof (dt_walk_env_t));
475 ir_node *end_block = get_irg_end_block (graph);
476 ir_node *start_block = get_irg_start_block (graph);
477 int n_blocks = get_n_blocks (graph);
478 dt_t *dt = get_dominator_tree (graph);
481 dt_walk_env_t *w = 0;
482 ir_node *end_block = 0;
483 ir_node *start_block = 0;
487 w = (dt_walk_env_t*) alloca (sizeof (dt_walk_env_t));
488 end_block = get_irg_end_block (graph);
489 start_block = get_irg_start_block (graph);
490 n_blocks = get_n_blocks (graph);
491 dt = get_dominator_tree (graph);
493 # ifdef DEBUG_libfirm
494 assert (graph && "no graph");
495 # endif /* def DEBUG_libfirm */
497 # ifdef VERBOSE_libfirm
498 fprintf (stdout, "%s: for graph(%p)\n", __FILE__ ":" __PRETTY_FUNCTION__, graph);
499 # endif /* def VERBOSE_libfirm */
507 w->start_block = start_block;
508 w->changed = true; /* at least one walk */
517 irg_block_walk (end_block, update_dominators, update_dominators, (void*) w);
521 # ifdef VERBOSE_libfirm
522 fprintf (stdout, "%s: for graph(%p): %i passes\n",
523 __FILE__ ":" __PRETTY_FUNCTION__, graph, walks);
524 # endif /* def VERBOSE_libfirm */
527 /* ok, now remember it: */
528 add_dominator_tree (dt);