2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
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.
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.
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
22 * @brief Chordal register allocation.
23 * @author Sebastian Hack
35 #include "raw_bitset.h"
37 #include "bipartite.h"
38 #include "hungarian.h"
41 #include "irgraph_t.h"
42 #include "irprintf_t.h"
60 #include "bestatevent.h"
62 #include "beintlive_t.h"
64 #include "bechordal_t.h"
65 #include "bechordal_draw.h"
68 #include "bechordal_common.h"
70 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
74 #define DUMP_INTERVALS
76 typedef struct be_chordal_alloc_env_t {
77 be_chordal_env_t *chordal_env;
79 pset *pre_colored; /**< Set of precolored nodes. */
80 bitset_t *live; /**< A liveness bitset. */
81 bitset_t *tmp_colors; /**< An auxiliary bitset which is as long as the number of colors in the class. */
82 bitset_t *colors; /**< The color mask. */
83 bitset_t *in_colors; /**< Colors used by live in values. */
84 int colors_n; /**< The number of colors. */
85 } be_chordal_alloc_env_t;
87 static int get_next_free_reg(const be_chordal_alloc_env_t *alloc_env, bitset_t *colors)
89 bitset_t *tmp = alloc_env->tmp_colors;
90 bitset_copy(tmp, colors);
92 bitset_and(tmp, alloc_env->chordal_env->allocatable_regs);
93 return bitset_next_set(tmp, 0);
96 static bitset_t *get_decisive_partner_regs(bitset_t *bs, const be_operand_t *o1, const be_operand_t *o2)
101 bitset_copy(bs, o2->regs);
106 bitset_copy(bs, o1->regs);
110 assert(o1->req->cls == o2->req->cls || ! o1->req->cls || ! o2->req->cls);
112 if (bitset_contains(o1->regs, o2->regs)) {
113 bitset_copy(bs, o1->regs);
114 } else if (bitset_contains(o2->regs, o1->regs)) {
115 bitset_copy(bs, o2->regs);
123 static void pair_up_operands(const be_chordal_alloc_env_t *alloc_env, be_insn_t *insn)
125 const be_chordal_env_t *env = alloc_env->chordal_env;
126 bitset_t *bs = bitset_alloca(env->cls->n_regs);
131 * For each out operand, try to find an in operand which can be assigned the
132 * same register as the out operand.
134 for (j = 0; j < insn->use_start; ++j) {
135 be_operand_t *smallest = NULL;
136 int smallest_n_regs = env->cls->n_regs + 1;
137 be_operand_t *out_op = &insn->ops[j];
139 /* Try to find an in operand which has ... */
140 for (i = insn->use_start; i < insn->n_ops; ++i) {
142 be_operand_t *op = &insn->ops[i];
145 if (op->partner != NULL)
147 lv = be_get_irg_liveness(env->irg);
148 if (be_values_interfere(lv, op->irn, op->carrier))
151 bitset_copy(bs, op->regs);
152 bitset_and(bs, out_op->regs);
153 n_total = bitset_popcount(op->regs);
155 if (!bitset_is_empty(bs) && n_total < smallest_n_regs) {
157 smallest_n_regs = n_total;
161 if (smallest != NULL) {
162 for (i = insn->use_start; i < insn->n_ops; ++i) {
163 if (insn->ops[i].carrier == smallest->carrier)
164 insn->ops[i].partner = out_op;
167 out_op->partner = smallest;
168 smallest->partner = out_op;
173 static ir_node *handle_constraints(be_chordal_alloc_env_t *alloc_env,
178 ir_node **alloc_nodes;
179 //hungarian_problem_t *bp;
184 const ir_edge_t *edge;
185 ir_node *perm = NULL;
186 //int match_res, cost;
187 be_chordal_env_t *env = alloc_env->chordal_env;
188 void *base = obstack_base(env->obst);
189 be_insn_t *insn = chordal_scan_insn(env, irn);
190 ir_node *res = insn->next_insn;
193 if (insn->pre_colored) {
195 for (i = 0; i < insn->use_start; ++i)
196 pset_insert_ptr(alloc_env->pre_colored, insn->ops[i].carrier);
200 * Perms inserted before the constraint handling phase are considered to be
201 * correctly precolored. These Perms arise during the ABI handling phase.
203 if (!insn->has_constraints)
206 n_regs = env->cls->n_regs;
207 bs = bitset_alloca(n_regs);
208 alloc_nodes = ALLOCAN(ir_node*, n_regs);
209 //bp = hungarian_new(n_regs, n_regs, 2, HUNGARIAN_MATCH_PERFECT);
210 bp = bipartite_new(n_regs, n_regs);
211 assignment = ALLOCAN(int, n_regs);
212 partners = pmap_create();
215 * prepare the constraint handling of this node.
216 * Perms are constructed and Copies are created for constrained values
217 * interfering with the instruction.
219 perm = pre_process_constraints(alloc_env->chordal_env, &insn);
221 /* find suitable in operands to the out operands of the node. */
222 pair_up_operands(alloc_env, insn);
225 * look at the in/out operands and add each operand (and its possible partner)
226 * to a bipartite graph (left: nodes with partners, right: admissible colors).
228 for (i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
229 be_operand_t *op = &insn->ops[i];
232 * If the operand has no partner or the partner has not been marked
233 * for allocation, determine the admissible registers and mark it
234 * for allocation by associating the node and its partner with the
235 * set of admissible registers via a bipartite graph.
237 if (!op->partner || !pmap_contains(partners, op->partner->carrier)) {
238 ir_node *partner = op->partner ? op->partner->carrier : NULL;
241 pmap_insert(partners, op->carrier, partner);
243 pmap_insert(partners, partner, op->carrier);
245 /* don't insert a node twice */
246 for (i = 0; i < n_alloc; ++i) {
247 if (alloc_nodes[i] == op->carrier) {
254 alloc_nodes[n_alloc] = op->carrier;
256 DBG((dbg, LEVEL_2, "\tassociating %+F and %+F\n", op->carrier,
259 bitset_clear_all(bs);
260 get_decisive_partner_regs(bs, op, op->partner);
262 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: %B\n", op->carrier,
265 bitset_foreach(bs, col) {
266 //hungarian_add(bp, n_alloc, col, 1);
267 bipartite_add(bp, n_alloc, col);
275 * Put all nodes which live through the constrained instruction also to the
276 * allocation bipartite graph. They are considered unconstrained.
279 foreach_out_edge(perm, edge) {
281 ir_node *proj = get_edge_src_irn(edge);
282 be_lv_t *lv = be_get_irg_liveness(env->irg);
284 assert(is_Proj(proj));
286 if (!be_values_interfere(lv, proj, irn)
287 || pmap_contains(partners, proj))
290 /* don't insert a node twice */
291 for (i = 0; i < n_alloc; ++i) {
292 if (alloc_nodes[i] == proj) {
300 assert(n_alloc < n_regs);
302 alloc_nodes[n_alloc] = proj;
303 pmap_insert(partners, proj, NULL);
305 bitset_foreach(env->allocatable_regs, col) {
306 //hungarian_add(bp, n_alloc, col, 1);
307 bipartite_add(bp, n_alloc, col);
314 /* Compute a valid register allocation. */
316 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
317 match_res = hungarian_solve(bp, assignment, &cost, 1);
318 assert(match_res == 0 && "matching failed");
320 /*bipartite_dump_f(stderr, bp);*/
321 bipartite_matching(bp, assignment);
324 /* Assign colors obtained from the matching. */
325 for (i = 0; i < n_alloc; ++i) {
326 const arch_register_t *reg;
329 assert(assignment[i] >= 0 && "there must have been a register assigned (node not register pressure faithful?)");
330 reg = arch_register_for_index(env->cls, assignment[i]);
332 irn = alloc_nodes[i];
334 arch_set_irn_register(irn, reg);
335 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
336 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
339 irn = (ir_node*)pmap_get(partners, alloc_nodes[i]);
341 arch_set_irn_register(irn, reg);
342 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
343 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
347 /* Allocate the non-constrained Projs of the Perm. */
349 bitset_clear_all(bs);
351 /* Put the colors of all Projs in a bitset. */
352 foreach_out_edge(perm, edge) {
353 ir_node *proj = get_edge_src_irn(edge);
354 const arch_register_t *reg = arch_get_irn_register(proj);
357 bitset_set(bs, reg->index);
360 /* Assign the not yet assigned Projs of the Perm a suitable color. */
361 foreach_out_edge(perm, edge) {
362 ir_node *proj = get_edge_src_irn(edge);
363 const arch_register_t *reg = arch_get_irn_register(proj);
365 DBG((dbg, LEVEL_2, "\tchecking reg of %+F: %s\n", proj, reg ? reg->name : "<none>"));
368 col = get_next_free_reg(alloc_env, bs);
369 reg = arch_register_for_index(env->cls, col);
370 bitset_set(bs, reg->index);
371 arch_set_irn_register(proj, reg);
372 pset_insert_ptr(alloc_env->pre_colored, proj);
373 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", proj, reg->name));
379 //hungarian_free(bp);
380 pmap_destroy(partners);
383 obstack_free(env->obst, base);
388 * Handle constraint nodes in each basic block.
389 * handle_constraints() inserts Perm nodes which perm
390 * over all values live at the constrained node right in front
391 * of the constrained node. These Perms signal a constrained node.
392 * For further comments, refer to handle_constraints().
394 static void constraints(ir_node *bl, void *data)
396 be_chordal_alloc_env_t *env = (be_chordal_alloc_env_t*)data;
399 for (irn = sched_first(bl); !sched_is_end(irn);) {
400 irn = handle_constraints(env, irn);
404 static void assign(ir_node *block, void *env_ptr)
406 be_chordal_alloc_env_t *alloc_env = (be_chordal_alloc_env_t*)env_ptr;
407 be_chordal_env_t *env = alloc_env->chordal_env;
408 bitset_t *live = alloc_env->live;
409 bitset_t *colors = alloc_env->colors;
410 bitset_t *in_colors = alloc_env->in_colors;
411 struct list_head *head = get_block_border_head(env, block);
412 be_lv_t *lv = be_get_irg_liveness(env->irg);
418 bitset_clear_all(colors);
419 bitset_clear_all(live);
420 bitset_clear_all(in_colors);
422 DBG((dbg, LEVEL_4, "Assigning colors for block %+F\n", block));
423 DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
424 list_for_each_entry(border_t, b, head, list) {
425 DBG((dbg, LEVEL_4, "\t%s %+F/%d\n", b->is_def ? "def" : "use",
426 b->irn, get_irn_idx(b->irn)));
430 * Add initial defs for all values live in.
431 * Since their colors have already been assigned (The dominators were
432 * allocated before), we have to mark their colors as used also.
434 be_lv_foreach(lv, block, be_lv_state_in, idx) {
435 irn = be_lv_get_irn(lv, block, idx);
436 if (has_reg_class(env, irn)) {
437 const arch_register_t *reg = arch_get_irn_register(irn);
440 assert(reg && "Node must have been assigned a register");
441 col = arch_register_get_index(reg);
443 DBG((dbg, LEVEL_4, "%+F has reg %s\n", irn, reg->name));
445 /* Mark the color of the live in value as used. */
446 bitset_set(colors, col);
447 bitset_set(in_colors, col);
449 /* Mark the value live in. */
450 bitset_set(live, get_irn_idx(irn));
455 * Mind that the sequence of defs from back to front defines a perfect
456 * elimination order. So, coloring the definitions from first to last
459 list_for_each_entry_reverse(border_t, b, head, list) {
460 ir_node *irn = b->irn;
461 int nr = get_irn_idx(irn);
462 int ignore = arch_irn_is_ignore(irn);
465 * Assign a color, if it is a local def. Global defs already have a
468 if (b->is_def && !be_is_live_in(lv, block, irn)) {
469 const arch_register_t *reg;
472 if (ignore || pset_find_ptr(alloc_env->pre_colored, irn)) {
473 reg = arch_get_irn_register(irn);
475 assert(!bitset_is_set(colors, col) && "pre-colored register must be free");
477 col = get_next_free_reg(alloc_env, colors);
478 reg = arch_register_for_index(env->cls, col);
479 assert(arch_get_irn_register(irn) == NULL && "This node must not have been assigned a register yet");
482 bitset_set(colors, col);
483 arch_set_irn_register(irn, reg);
485 DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", arch_register_get_name(reg), col, irn));
487 assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
488 bitset_set(live, nr);
489 } else if (!b->is_def) {
490 /* Clear the color upon a use. */
491 const arch_register_t *reg = arch_get_irn_register(irn);
494 assert(reg && "Register must have been assigned");
496 col = arch_register_get_index(reg);
498 bitset_clear(colors, col);
499 bitset_clear(live, nr);
504 void be_ra_chordal_color(be_chordal_env_t *chordal_env)
506 be_chordal_alloc_env_t env;
509 const arch_register_class_t *cls = chordal_env->cls;
511 int colors_n = arch_register_class_n_regs(cls);
512 ir_graph *irg = chordal_env->irg;
514 lv = be_assure_liveness(irg);
515 be_liveness_assure_sets(lv);
516 be_liveness_assure_chk(lv);
520 env.chordal_env = chordal_env;
521 env.colors_n = colors_n;
522 env.colors = bitset_alloca(colors_n);
523 env.tmp_colors = bitset_alloca(colors_n);
524 env.in_colors = bitset_alloca(colors_n);
525 env.pre_colored = pset_new_ptr_default();
527 be_timer_push(T_CONSTR);
529 /* Handle register targeting constraints */
530 dom_tree_walk_irg(irg, constraints, NULL, &env);
532 if (chordal_env->opts->dump_flags & BE_CH_DUMP_CONSTR) {
533 snprintf(buf, sizeof(buf), "%s-constr", chordal_env->cls->name);
534 dump_ir_graph(chordal_env->irg, buf);
537 be_timer_pop(T_CONSTR);
539 env.live = bitset_malloc(get_irg_last_idx(chordal_env->irg));
541 /* First, determine the pressure */
542 dom_tree_walk_irg(irg, create_borders, NULL, env.chordal_env);
544 /* Assign the colors */
545 dom_tree_walk_irg(irg, assign, NULL, &env);
547 if (chordal_env->opts->dump_flags & BE_CH_DUMP_TREE_INTV) {
549 ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
550 plotter = new_plotter_ps(buf);
551 draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
552 plotter_free(plotter);
555 bitset_free(env.live);
556 del_pset(env.pre_colored);
559 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal);
560 void be_init_chordal(void)
562 static be_ra_chordal_coloring_t coloring = {
565 FIRM_DBG_REGISTER(dbg, "firm.be.chordal");
567 be_register_chordal_coloring("default", &coloring);