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
34 #include "raw_bitset.h"
36 #include "bipartite.h"
37 #include "hungarian.h"
40 #include "irgraph_t.h"
41 #include "irprintf_t.h"
58 #include "bestatevent.h"
60 #include "beintlive_t.h"
62 #include "bechordal_t.h"
63 #include "bechordal_draw.h"
66 #include "bechordal_common.h"
68 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
70 #define DUMP_INTERVALS
72 typedef struct be_chordal_alloc_env_t {
73 be_chordal_env_t *chordal_env;
75 pset *pre_colored; /**< Set of precolored nodes. */
76 bitset_t *live; /**< A liveness bitset. */
77 bitset_t *tmp_colors; /**< An auxiliary bitset which is as long as the number of colors in the class. */
78 bitset_t *colors; /**< The color mask. */
79 bitset_t *in_colors; /**< Colors used by live in values. */
80 int colors_n; /**< The number of colors. */
81 } be_chordal_alloc_env_t;
83 static int get_next_free_reg(const be_chordal_alloc_env_t *alloc_env, bitset_t *colors)
85 bitset_t *tmp = alloc_env->tmp_colors;
86 bitset_copy(tmp, colors);
88 bitset_and(tmp, alloc_env->chordal_env->allocatable_regs);
89 return bitset_next_set(tmp, 0);
92 static bitset_t *get_decisive_partner_regs(bitset_t *bs, const be_operand_t *o1, const be_operand_t *o2)
97 bitset_copy(bs, o2->regs);
102 bitset_copy(bs, o1->regs);
106 assert(o1->req->cls == o2->req->cls || ! o1->req->cls || ! o2->req->cls);
108 if (bitset_contains(o1->regs, o2->regs)) {
109 bitset_copy(bs, o1->regs);
110 } else if (bitset_contains(o2->regs, o1->regs)) {
111 bitset_copy(bs, o2->regs);
119 static void pair_up_operands(const be_chordal_alloc_env_t *alloc_env, be_insn_t *insn)
121 const be_chordal_env_t *env = alloc_env->chordal_env;
122 bitset_t *bs = bitset_alloca(env->cls->n_regs);
127 * For each out operand, try to find an in operand which can be assigned the
128 * same register as the out operand.
130 for (j = 0; j < insn->use_start; ++j) {
131 be_operand_t *smallest = NULL;
132 int smallest_n_regs = env->cls->n_regs + 1;
133 be_operand_t *out_op = &insn->ops[j];
135 /* Try to find an in operand which has ... */
136 for (i = insn->use_start; i < insn->n_ops; ++i) {
138 be_operand_t *op = &insn->ops[i];
141 if (op->partner != NULL)
143 lv = be_get_irg_liveness(env->irg);
144 if (be_values_interfere(lv, op->irn, op->carrier))
147 bitset_copy(bs, op->regs);
148 bitset_and(bs, out_op->regs);
149 n_total = bitset_popcount(op->regs);
151 if (!bitset_is_empty(bs) && n_total < smallest_n_regs) {
153 smallest_n_regs = n_total;
157 if (smallest != NULL) {
158 for (i = insn->use_start; i < insn->n_ops; ++i) {
159 if (insn->ops[i].carrier == smallest->carrier)
160 insn->ops[i].partner = out_op;
163 out_op->partner = smallest;
164 smallest->partner = out_op;
169 static ir_node *handle_constraints(be_chordal_alloc_env_t *alloc_env,
174 ir_node **alloc_nodes;
175 //hungarian_problem_t *bp;
179 ir_node *perm = NULL;
180 //int match_res, cost;
181 be_chordal_env_t *env = alloc_env->chordal_env;
182 void *base = obstack_base(env->obst);
183 be_insn_t *insn = chordal_scan_insn(env, irn);
184 ir_node *res = insn->next_insn;
187 if (insn->pre_colored) {
189 for (i = 0; i < insn->use_start; ++i)
190 pset_insert_ptr(alloc_env->pre_colored, insn->ops[i].carrier);
194 * Perms inserted before the constraint handling phase are considered to be
195 * correctly precolored. These Perms arise during the ABI handling phase.
197 if (!insn->has_constraints || is_Phi(irn))
200 n_regs = env->cls->n_regs;
201 bs = bitset_alloca(n_regs);
202 alloc_nodes = ALLOCAN(ir_node*, n_regs);
203 //bp = hungarian_new(n_regs, n_regs, 2, HUNGARIAN_MATCH_PERFECT);
204 bp = bipartite_new(n_regs, n_regs);
205 assignment = ALLOCAN(int, n_regs);
206 partners = pmap_create();
209 * prepare the constraint handling of this node.
210 * Perms are constructed and Copies are created for constrained values
211 * interfering with the instruction.
213 perm = pre_process_constraints(alloc_env->chordal_env, &insn);
215 /* find suitable in operands to the out operands of the node. */
216 pair_up_operands(alloc_env, insn);
219 * look at the in/out operands and add each operand (and its possible partner)
220 * to a bipartite graph (left: nodes with partners, right: admissible colors).
222 for (i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
223 be_operand_t *op = &insn->ops[i];
226 * If the operand has no partner or the partner has not been marked
227 * for allocation, determine the admissible registers and mark it
228 * for allocation by associating the node and its partner with the
229 * set of admissible registers via a bipartite graph.
231 if (!op->partner || !pmap_contains(partners, op->partner->carrier)) {
232 ir_node *partner = op->partner ? op->partner->carrier : NULL;
235 pmap_insert(partners, op->carrier, partner);
237 pmap_insert(partners, partner, op->carrier);
239 /* don't insert a node twice */
240 for (i = 0; i < n_alloc; ++i) {
241 if (alloc_nodes[i] == op->carrier) {
248 alloc_nodes[n_alloc] = op->carrier;
250 DBG((dbg, LEVEL_2, "\tassociating %+F and %+F\n", op->carrier,
253 bitset_clear_all(bs);
254 get_decisive_partner_regs(bs, op, op->partner);
256 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: %B\n", op->carrier,
259 bitset_foreach(bs, col) {
260 //hungarian_add(bp, n_alloc, col, 1);
261 bipartite_add(bp, n_alloc, col);
269 * Put all nodes which live through the constrained instruction also to the
270 * allocation bipartite graph. They are considered unconstrained.
273 foreach_out_edge(perm, edge) {
275 ir_node *proj = get_edge_src_irn(edge);
276 be_lv_t *lv = be_get_irg_liveness(env->irg);
278 assert(is_Proj(proj));
280 if (!be_values_interfere(lv, proj, irn)
281 || pmap_contains(partners, proj))
284 /* don't insert a node twice */
285 for (i = 0; i < n_alloc; ++i) {
286 if (alloc_nodes[i] == proj) {
294 assert(n_alloc < n_regs);
296 alloc_nodes[n_alloc] = proj;
297 pmap_insert(partners, proj, NULL);
299 bitset_foreach(env->allocatable_regs, col) {
300 //hungarian_add(bp, n_alloc, col, 1);
301 bipartite_add(bp, n_alloc, col);
308 /* Compute a valid register allocation. */
310 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
311 match_res = hungarian_solve(bp, assignment, &cost, 1);
312 assert(match_res == 0 && "matching failed");
314 /*bipartite_dump_f(stderr, bp);*/
315 bipartite_matching(bp, assignment);
318 /* Assign colors obtained from the matching. */
319 for (i = 0; i < n_alloc; ++i) {
320 const arch_register_t *reg;
323 assert(assignment[i] >= 0 && "there must have been a register assigned (node not register pressure faithful?)");
324 reg = arch_register_for_index(env->cls, assignment[i]);
326 irn = alloc_nodes[i];
328 arch_set_irn_register(irn, reg);
329 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
330 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
333 irn = pmap_get(ir_node, partners, alloc_nodes[i]);
335 arch_set_irn_register(irn, reg);
336 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
337 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
341 /* Allocate the non-constrained Projs of the Perm. */
343 bitset_clear_all(bs);
345 /* Put the colors of all Projs in a bitset. */
346 foreach_out_edge(perm, edge) {
347 ir_node *proj = get_edge_src_irn(edge);
348 const arch_register_t *reg = arch_get_irn_register(proj);
351 bitset_set(bs, reg->index);
354 /* Assign the not yet assigned Projs of the Perm a suitable color. */
355 foreach_out_edge(perm, edge) {
356 ir_node *proj = get_edge_src_irn(edge);
357 const arch_register_t *reg = arch_get_irn_register(proj);
359 DBG((dbg, LEVEL_2, "\tchecking reg of %+F: %s\n", proj, reg ? reg->name : "<none>"));
362 size_t const col = get_next_free_reg(alloc_env, bs);
363 reg = arch_register_for_index(env->cls, col);
364 bitset_set(bs, reg->index);
365 arch_set_irn_register(proj, reg);
366 pset_insert_ptr(alloc_env->pre_colored, proj);
367 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", proj, reg->name));
373 //hungarian_free(bp);
374 pmap_destroy(partners);
377 obstack_free(env->obst, base);
382 * Handle constraint nodes in each basic block.
383 * handle_constraints() inserts Perm nodes which perm
384 * over all values live at the constrained node right in front
385 * of the constrained node. These Perms signal a constrained node.
386 * For further comments, refer to handle_constraints().
388 static void constraints(ir_node *bl, void *data)
390 be_chordal_alloc_env_t *env = (be_chordal_alloc_env_t*)data;
393 for (irn = sched_first(bl); !sched_is_end(irn);) {
394 irn = handle_constraints(env, irn);
398 static void assign(ir_node *block, void *env_ptr)
400 be_chordal_alloc_env_t *alloc_env = (be_chordal_alloc_env_t*)env_ptr;
401 be_chordal_env_t *env = alloc_env->chordal_env;
402 bitset_t *live = alloc_env->live;
403 bitset_t *colors = alloc_env->colors;
404 bitset_t *in_colors = alloc_env->in_colors;
405 struct list_head *head = get_block_border_head(env, block);
406 be_lv_t *lv = be_get_irg_liveness(env->irg);
412 bitset_clear_all(colors);
413 bitset_clear_all(live);
414 bitset_clear_all(in_colors);
416 DBG((dbg, LEVEL_4, "Assigning colors for block %+F\n", block));
417 DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
418 list_for_each_entry(border_t, b, head, list) {
419 DBG((dbg, LEVEL_4, "\t%s %+F/%d\n", b->is_def ? "def" : "use",
420 b->irn, get_irn_idx(b->irn)));
424 * Add initial defs for all values live in.
425 * Since their colors have already been assigned (The dominators were
426 * allocated before), we have to mark their colors as used also.
428 be_lv_foreach(lv, block, be_lv_state_in, idx) {
429 irn = be_lv_get_irn(lv, block, idx);
430 if (has_reg_class(env, irn)) {
431 const arch_register_t *reg = arch_get_irn_register(irn);
434 assert(reg && "Node must have been assigned a register");
435 col = arch_register_get_index(reg);
437 DBG((dbg, LEVEL_4, "%+F has reg %s\n", irn, reg->name));
439 /* Mark the color of the live in value as used. */
440 bitset_set(colors, col);
441 bitset_set(in_colors, col);
443 /* Mark the value live in. */
444 bitset_set(live, get_irn_idx(irn));
449 * Mind that the sequence of defs from back to front defines a perfect
450 * elimination order. So, coloring the definitions from first to last
453 list_for_each_entry_reverse(border_t, b, head, list) {
454 ir_node *irn = b->irn;
455 int nr = get_irn_idx(irn);
456 int ignore = arch_irn_is_ignore(irn);
459 * Assign a color, if it is a local def. Global defs already have a
462 if (b->is_def && !be_is_live_in(lv, block, irn)) {
463 const arch_register_t *reg;
466 if (ignore || pset_find_ptr(alloc_env->pre_colored, irn)) {
467 reg = arch_get_irn_register(irn);
469 assert(!bitset_is_set(colors, col) && "pre-colored register must be free");
471 col = get_next_free_reg(alloc_env, colors);
472 reg = arch_register_for_index(env->cls, col);
473 assert(arch_get_irn_register(irn) == NULL && "This node must not have been assigned a register yet");
476 bitset_set(colors, col);
477 arch_set_irn_register(irn, reg);
479 DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", arch_register_get_name(reg), col, irn));
481 assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
482 bitset_set(live, nr);
483 } else if (!b->is_def) {
484 /* Clear the color upon a use. */
485 const arch_register_t *reg = arch_get_irn_register(irn);
488 assert(reg && "Register must have been assigned");
490 col = arch_register_get_index(reg);
492 bitset_clear(colors, col);
493 bitset_clear(live, nr);
498 void be_ra_chordal_color(be_chordal_env_t *chordal_env)
500 be_chordal_alloc_env_t env;
502 const arch_register_class_t *cls = chordal_env->cls;
504 int colors_n = arch_register_class_n_regs(cls);
505 ir_graph *irg = chordal_env->irg;
507 be_assure_live_sets(irg);
510 env.chordal_env = chordal_env;
511 env.colors_n = colors_n;
512 env.colors = bitset_alloca(colors_n);
513 env.tmp_colors = bitset_alloca(colors_n);
514 env.in_colors = bitset_alloca(colors_n);
515 env.pre_colored = pset_new_ptr_default();
517 be_timer_push(T_SPLIT);
519 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPLIT) {
520 snprintf(buf, sizeof(buf), "%s-split", chordal_env->cls->name);
521 dump_ir_graph(chordal_env->irg, buf);
524 be_timer_pop(T_SPLIT);
526 be_timer_push(T_CONSTR);
528 /* Handle register targeting constraints */
529 dom_tree_walk_irg(irg, constraints, NULL, &env);
531 if (chordal_env->opts->dump_flags & BE_CH_DUMP_CONSTR) {
532 snprintf(buf, sizeof(buf), "%s-constr", chordal_env->cls->name);
533 dump_ir_graph(chordal_env->irg, buf);
536 be_timer_pop(T_CONSTR);
538 env.live = bitset_malloc(get_irg_last_idx(chordal_env->irg));
540 /* First, determine the pressure */
541 dom_tree_walk_irg(irg, create_borders, NULL, env.chordal_env);
543 /* Assign the colors */
544 dom_tree_walk_irg(irg, assign, NULL, &env);
546 if (chordal_env->opts->dump_flags & BE_CH_DUMP_TREE_INTV) {
548 ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
549 plotter = new_plotter_ps(buf);
550 draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
551 plotter_free(plotter);
554 bitset_free(env.live);
555 del_pset(env.pre_colored);
558 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal)
559 void be_init_chordal(void)
561 static be_ra_chordal_coloring_t coloring = {
564 FIRM_DBG_REGISTER(dbg, "firm.be.chordal");
566 be_register_chordal_coloring("default", &coloring);