s/\<\(LC_\)\?INLINE\>/inline/.
[libfirm] / ir / be / beuses.c
1 /*
2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
3  *
4  * This file is part of libFirm.
5  *
6  * This file may be distributed and/or modified under the terms of the
7  * GNU General Public License version 2 as published by the Free Software
8  * Foundation and appearing in the file LICENSE.GPL included in the
9  * packaging of this file.
10  *
11  * Licensees holding valid libFirm Professional Edition licenses may use
12  * this file in accordance with the libFirm Commercial License.
13  * Agreement provided with the Software.
14  *
15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17  * PURPOSE.
18  */
19
20 /**
21  * @file
22  * @brief       Methods to compute when a value will be used again.
23  * @author      Sebastian Hack, Matthias Braun
24  * @date        27.06.2005
25  * @version     $Id$
26  */
27 #include "config.h"
28
29 #include <limits.h>
30 #include <stdlib.h>
31
32 #include "config.h"
33 #include "obst.h"
34 #include "pmap.h"
35 #include "debug.h"
36
37 #include "irgwalk.h"
38 #include "irnode_t.h"
39 #include "ircons_t.h"
40 #include "irgraph_t.h"
41 #include "iredges_t.h"
42 #include "irdom_t.h"
43
44 #include "be_t.h"
45 #include "beutil.h"
46 #include "belive_t.h"
47 #include "benode_t.h"
48 #include "besched_t.h"
49 #include "beirgmod.h"
50 #include "bearch_t.h"
51 #include "beuses.h"
52
53 #define SCAN_INTERBLOCK_USES
54
55 typedef struct _be_use_t {
56         const ir_node *block;
57         const ir_node *node;
58         int outermost_loop;
59         unsigned next_use;
60         unsigned visited;
61 } be_use_t;
62
63 struct _be_uses_t {
64         set *uses;
65         ir_graph *irg;
66         const be_lv_t *lv;
67         unsigned visited_counter;
68         DEBUG_ONLY(firm_dbg_module_t *dbg;)
69 };
70
71 static int cmp_use(const void *a, const void *b, size_t n)
72 {
73         const be_use_t *p = a;
74         const be_use_t *q = b;
75         (void) n;
76
77         return !(p->block == q->block && p->node == q->node);
78 }
79
80 static be_next_use_t get_next_use(be_uses_t *env, ir_node *from,
81                                                                   unsigned from_step, const ir_node *def,
82                                                                   int skip_from_uses);
83
84 static const be_use_t *get_or_set_use_block(be_uses_t *env,
85                                             const ir_node *block,
86                                             const ir_node *def)
87 {
88         unsigned hash = HASH_COMBINE(hash_irn(block), hash_irn(def));
89         be_use_t temp;
90         be_use_t* result;
91
92         temp.block = block;
93         temp.node = def;
94         result = set_find(env->uses, &temp, sizeof(temp), hash);
95
96         if(result == NULL) {
97                 // insert templ first as we might end in a loop in the get_next_use
98                 // call otherwise
99                 temp.next_use = USES_INFINITY;
100                 temp.outermost_loop = -1;
101                 temp.visited = 0;
102                 result = set_insert(env->uses, &temp, sizeof(temp), hash);
103         }
104
105         if(result->outermost_loop < 0 && result->visited < env->visited_counter) {
106                 be_next_use_t next_use;
107
108                 result->visited = env->visited_counter;
109                 next_use = get_next_use(env, sched_first(block), 0, def, 0);
110                 if(next_use.outermost_loop >= 0) {
111                         result->next_use = next_use.time;
112                         result->outermost_loop = next_use.outermost_loop;
113                         DBG((env->dbg, LEVEL_5, "Setting nextuse of %+F in block %+F to %u (outermostloop %d)\n", def, block, result->next_use, result->outermost_loop));
114                 }
115         }
116
117         return result;
118 }
119
120 static int be_is_phi_argument(const ir_node *block, const ir_node *def)
121 {
122         ir_node *node;
123         ir_node *succ_block = NULL;
124         const ir_edge_t *edge;
125         int arity, i;
126
127 #if 1
128         if (get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) < 1)
129 #else
130         if (get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) != 1)
131 #endif
132                 return 0;
133
134         foreach_block_succ(block, edge) {
135                 succ_block = get_edge_src_irn(edge);
136                 break;
137         }
138
139         arity = get_Block_n_cfgpreds(succ_block);
140         if(arity <= 1)
141                 return 0;
142
143         for(i = 0; i < arity; ++i) {
144                 if(get_Block_cfgpred_block(succ_block, i) == block)
145                         break;
146         }
147         assert(i < arity);
148
149         sched_foreach(succ_block, node) {
150                 ir_node *arg;
151
152                 if(!is_Phi(node))
153                         break;
154
155                 arg = get_irn_n(node, i);
156                 if(arg == def)
157                         return 1;
158         }
159
160         return 0;
161 }
162
163 static inline
164 unsigned get_step(const ir_node *node)
165 {
166         return PTR_TO_INT(get_irn_link(node));
167 }
168
169 static be_next_use_t get_next_use(be_uses_t *env, ir_node *from,
170                                                                   unsigned from_step, const ir_node *def,
171                                                                   int skip_from_uses)
172 {
173         unsigned  step  = from_step;
174         ir_node  *block = get_nodes_block(from);
175         ir_node  *next_use;
176         ir_node  *node;
177         unsigned  timestep;
178         unsigned  next_use_step;
179         const ir_edge_t *edge;
180
181 #if 1
182         assert(skip_from_uses == 0 || skip_from_uses == 1);
183         if(skip_from_uses) {
184                 from = sched_next(from);
185         }
186
187         next_use      = NULL;
188         next_use_step = INT_MAX;
189         timestep      = get_step(from);
190         foreach_out_edge(def, edge) {
191                 ir_node  *node = get_edge_src_irn(edge);
192                 unsigned  node_step;
193
194                 if(is_Anchor(node))
195                         continue;
196                 if(get_nodes_block(node) != block)
197                         continue;
198                 if(is_Phi(node))
199                         continue;
200
201                 node_step = get_step(node);
202                 if(node_step < timestep)
203                         continue;
204                 if(node_step < next_use_step) {
205                         next_use      = node;
206                         next_use_step = node_step;
207                 }
208         }
209
210         if(next_use != NULL) {
211                 be_next_use_t result;
212                 result.time           = next_use_step - timestep + skip_from_uses;
213                 result.outermost_loop = get_loop_depth(get_irn_loop(block));
214                 result.before         = next_use;
215                 return result;
216         }
217
218         node = sched_last(block);
219         step = get_step(node) + 1 + timestep + skip_from_uses;
220
221 #else
222         if(skip_from_uses) {
223                 from = sched_next(from);
224                 ++step;
225         }
226
227         sched_foreach_from(from, node) {
228                 int i, arity;
229
230                 if(is_Phi(node)) {
231                         step++;
232                         continue;
233                 }
234
235                 arity = get_irn_arity(node);
236                 for (i = 0; i < arity; ++i) {
237                         const ir_node *operand = get_irn_n(node, i);
238
239                         if (operand == def) {
240                                 be_next_use_t result;
241
242                                 DBG((env->dbg, LEVEL_3, "found use of %+F at %+F\n", operand, node));
243
244                                 /**
245                                  * Spills/Reloads are a special case, they're not really a
246                                  * usage of a value, continue searching
247                                  */
248                                 if (be_is_Spill(node) || be_is_Reload(node)) {
249                                         return be_get_next_use(env, node, step, node, 1);
250                                 }
251
252                                 result.time           = step;
253                                 result.outermost_loop = get_loop_depth(get_irn_loop(block));
254                                 result.before         = node;
255                                 return result;
256                         }
257                 }
258
259                 step++;
260         }
261 #endif
262
263         if(be_is_phi_argument(block, def)) {
264                 // TODO we really should continue searching the uses of the phi,
265                 // as a phi isn't a real use that implies a reload (because we could
266                 // easily spill the whole phi)
267
268                 be_next_use_t result;
269                 result.time           = step;
270                 result.outermost_loop = get_loop_depth(get_irn_loop(block));
271                 result.before         = block;
272                 return result;
273         }
274
275 #ifdef SCAN_INTERBLOCK_USES
276         {
277         unsigned next_use   = USES_INFINITY;
278         int outermost_loop;
279         be_next_use_t result;
280         ir_loop *loop       = get_irn_loop(block);
281         int loopdepth       = get_loop_depth(loop);
282         int found_visited   = 0;
283         int found_use       = 0;
284         ir_graph *irg       = get_irn_irg(block);
285         ir_node *startblock = get_irg_start_block(irg);
286
287         result.before  = NULL;
288         outermost_loop = loopdepth;
289         foreach_block_succ(block, edge) {
290                 const be_use_t *use;
291                 const ir_node *succ_block = get_edge_src_irn(edge);
292                 ir_loop *succ_loop;
293                 unsigned use_dist;
294
295                 if(succ_block == startblock)
296                         continue;
297
298                 DBG((env->dbg, LEVEL_5, "Checking succ of block %+F: %+F (for use of %+F)\n", block, succ_block, def));
299                 if(!be_is_live_in(env->lv, succ_block, def)) {
300                         //next_use = USES_INFINITY;
301                         DBG((env->dbg, LEVEL_5, "   not live in\n"));
302                         continue;
303                 }
304
305                 use = get_or_set_use_block(env, succ_block, def);
306                 DBG((env->dbg, LEVEL_5, "Found %u (loopdepth %d) (we're in block %+F)\n", use->next_use,
307                                         use->outermost_loop, block));
308                 if(USES_IS_INFINITE(use->next_use)) {
309                         if(use->outermost_loop < 0) {
310                                 found_visited = 1;
311                         }
312                         continue;
313                 }
314
315                 found_use = 1;
316                 use_dist = use->next_use;
317
318                 succ_loop = get_irn_loop(succ_block);
319                 if(get_loop_depth(succ_loop) < loopdepth) {
320                         unsigned factor = (loopdepth - get_loop_depth(succ_loop)) * 5000;
321                         DBG((env->dbg, LEVEL_5, "Increase usestep because of loop out edge %d -> %d (%u)\n", factor));
322                         // TODO we should use the number of nodes in the loop or so...
323                         use_dist += factor;
324                 }
325
326                 if(use_dist < next_use) {
327                         next_use       = use_dist;
328                         outermost_loop = use->outermost_loop;
329                         result.before  = use->node;
330                 }
331         }
332
333         if(loopdepth < outermost_loop)
334                 outermost_loop = loopdepth;
335
336         result.time           = next_use + step;
337         result.outermost_loop = outermost_loop;
338
339         if(!found_use && found_visited) {
340                 // the current result is correct for the current search, but isn't
341                 // generally correct, so mark it
342                 result.outermost_loop = -1;
343         }
344         DBG((env->dbg, LEVEL_5, "Result: %d (outerloop: %d)\n", result.time, result.outermost_loop));
345         return result;
346         }
347 #else
348         return USES_INFINITY;
349 #endif
350 }
351
352 be_next_use_t be_get_next_use(be_uses_t *env, ir_node *from,
353                          unsigned from_step, const ir_node *def,
354                          int skip_from_uses)
355 {
356         env->visited_counter++;
357         return get_next_use(env, from, from_step, def, skip_from_uses);
358 }
359
360 static
361 void set_sched_step_walker(ir_node *block, void *data)
362 {
363         ir_node  *node;
364         unsigned step = 0;
365         (void) data;
366
367         sched_foreach(block, node) {
368                 set_irn_link(node, INT_TO_PTR(step));
369                 if(is_Phi(node))
370                         continue;
371                 ++step;
372         }
373 }
374
375 be_uses_t *be_begin_uses(ir_graph *irg, const be_lv_t *lv)
376 {
377         be_uses_t *env = XMALLOC(be_uses_t);
378
379         edges_assure(irg);
380
381         //set_using_irn_link(irg);
382
383         /* precalculate sched steps */
384         irg_block_walk_graph(irg, set_sched_step_walker, NULL, NULL);
385
386         env->uses = new_set(cmp_use, 512);
387         env->irg = irg;
388         env->lv = lv;
389         env->visited_counter = 0;
390         FIRM_DBG_REGISTER(env->dbg, "firm.be.uses");
391
392         return env;
393 }
394
395 void be_end_uses(be_uses_t *env)
396 {
397         //clear_using_irn_link(env->irg);
398         del_set(env->uses);
399         free(env);
400 }