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"
35 #include "bipartite.h"
36 #include "hungarian.h"
39 #include "irgraph_t.h"
40 #include "irprintf_t.h"
59 #include "beintlive_t.h"
61 #include "bechordal_t.h"
62 #include "bechordal_draw.h"
65 #include "bechordal_common.h"
67 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
69 typedef struct be_chordal_alloc_env_t {
70 be_chordal_env_t *chordal_env;
72 pset *pre_colored; /**< Set of precolored nodes. */
73 bitset_t *live; /**< A liveness bitset. */
74 bitset_t *tmp_colors; /**< An auxiliary bitset which is as long as the number of colors in the class. */
75 bitset_t *colors; /**< The color mask. */
76 int colors_n; /**< The number of colors. */
77 } be_chordal_alloc_env_t;
79 static int get_next_free_reg(const be_chordal_alloc_env_t *alloc_env, bitset_t *colors)
81 bitset_t *tmp = alloc_env->tmp_colors;
82 bitset_copy(tmp, colors);
84 bitset_and(tmp, alloc_env->chordal_env->allocatable_regs);
85 return bitset_next_set(tmp, 0);
88 static bitset_t const *get_decisive_partner_regs(be_operand_t const *const o1)
90 be_operand_t const *const o2 = o1->partner;
91 assert(!o2 || o1->req->cls == o2->req->cls);
93 if (!o2 || bitset_contains(o1->regs, o2->regs)) {
95 } else if (bitset_contains(o2->regs, o1->regs)) {
102 static void pair_up_operands(const be_chordal_alloc_env_t *alloc_env, be_insn_t *insn)
104 const be_chordal_env_t *env = alloc_env->chordal_env;
105 bitset_t *bs = bitset_alloca(env->cls->n_regs);
110 * For each out operand, try to find an in operand which can be assigned the
111 * same register as the out operand.
113 for (j = 0; j < insn->use_start; ++j) {
114 be_operand_t *smallest = NULL;
115 int smallest_n_regs = env->cls->n_regs + 1;
116 be_operand_t *out_op = &insn->ops[j];
118 /* Try to find an in operand which has ... */
119 for (i = insn->use_start; i < insn->n_ops; ++i) {
121 be_operand_t *op = &insn->ops[i];
124 if (op->partner != NULL)
126 lv = be_get_irg_liveness(env->irg);
127 if (be_values_interfere(lv, op->irn, op->carrier))
130 bitset_copy(bs, op->regs);
131 bitset_and(bs, out_op->regs);
132 n_total = bitset_popcount(op->regs);
134 if (!bitset_is_empty(bs) && n_total < smallest_n_regs) {
136 smallest_n_regs = n_total;
140 if (smallest != NULL) {
141 for (i = insn->use_start; i < insn->n_ops; ++i) {
142 if (insn->ops[i].carrier == smallest->carrier)
143 insn->ops[i].partner = out_op;
146 out_op->partner = smallest;
147 smallest->partner = out_op;
152 static void handle_constraints(be_chordal_alloc_env_t *alloc_env,
156 ir_node **alloc_nodes;
157 //hungarian_problem_t *bp;
161 ir_node *perm = NULL;
162 //int match_res, cost;
163 be_chordal_env_t *env = alloc_env->chordal_env;
164 void *base = obstack_base(env->obst);
165 be_insn_t *insn = be_scan_insn(env, irn);
168 if (insn->pre_colored) {
170 for (i = 0; i < insn->use_start; ++i)
171 pset_insert_ptr(alloc_env->pre_colored, insn->ops[i].carrier);
175 * Perms inserted before the constraint handling phase are considered to be
176 * correctly precolored. These Perms arise during the ABI handling phase.
178 if (!insn->has_constraints || is_Phi(irn))
181 n_regs = env->cls->n_regs;
182 alloc_nodes = ALLOCAN(ir_node*, n_regs);
183 //bp = hungarian_new(n_regs, n_regs, 2, HUNGARIAN_MATCH_PERFECT);
184 bp = bipartite_new(n_regs, n_regs);
185 assignment = ALLOCAN(int, n_regs);
186 partners = pmap_create();
189 * prepare the constraint handling of this node.
190 * Perms are constructed and Copies are created for constrained values
191 * interfering with the instruction.
193 perm = pre_process_constraints(alloc_env->chordal_env, &insn);
195 /* find suitable in operands to the out operands of the node. */
196 pair_up_operands(alloc_env, insn);
199 * look at the in/out operands and add each operand (and its possible partner)
200 * to a bipartite graph (left: nodes with partners, right: admissible colors).
202 for (i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
203 be_operand_t *op = &insn->ops[i];
206 * If the operand has no partner or the partner has not been marked
207 * for allocation, determine the admissible registers and mark it
208 * for allocation by associating the node and its partner with the
209 * set of admissible registers via a bipartite graph.
211 if (!op->partner || !pmap_contains(partners, op->partner->carrier)) {
212 ir_node *partner = op->partner ? op->partner->carrier : NULL;
215 pmap_insert(partners, op->carrier, partner);
217 pmap_insert(partners, partner, op->carrier);
219 /* don't insert a node twice */
220 for (i = 0; i < n_alloc; ++i) {
221 if (alloc_nodes[i] == op->carrier) {
228 alloc_nodes[n_alloc] = op->carrier;
230 DBG((dbg, LEVEL_2, "\tassociating %+F and %+F\n", op->carrier,
233 bitset_t const *const bs = get_decisive_partner_regs(op);
235 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: %B\n", op->carrier, bs));
237 bitset_foreach(bs, col) {
238 //hungarian_add(bp, n_alloc, col, 1);
239 bipartite_add(bp, n_alloc, col);
242 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: none\n", op->carrier));
250 * Put all nodes which live through the constrained instruction also to the
251 * allocation bipartite graph. They are considered unconstrained.
254 foreach_out_edge(perm, edge) {
256 ir_node *proj = get_edge_src_irn(edge);
257 be_lv_t *lv = be_get_irg_liveness(env->irg);
259 assert(is_Proj(proj));
261 if (!be_values_interfere(lv, proj, irn)
262 || pmap_contains(partners, proj))
265 /* don't insert a node twice */
266 for (i = 0; i < n_alloc; ++i) {
267 if (alloc_nodes[i] == proj) {
275 assert(n_alloc < n_regs);
277 alloc_nodes[n_alloc] = proj;
278 pmap_insert(partners, proj, NULL);
280 bitset_foreach(env->allocatable_regs, col) {
281 //hungarian_add(bp, n_alloc, col, 1);
282 bipartite_add(bp, n_alloc, col);
289 /* Compute a valid register allocation. */
291 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
292 match_res = hungarian_solve(bp, assignment, &cost, 1);
293 assert(match_res == 0 && "matching failed");
295 /*bipartite_dump_f(stderr, bp);*/
296 bipartite_matching(bp, assignment);
299 /* Assign colors obtained from the matching. */
300 for (i = 0; i < n_alloc; ++i) {
301 const arch_register_t *reg;
304 assert(assignment[i] >= 0 && "there must have been a register assigned (node not register pressure faithful?)");
305 reg = arch_register_for_index(env->cls, assignment[i]);
307 irn = alloc_nodes[i];
309 arch_set_irn_register(irn, reg);
310 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
311 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
314 irn = pmap_get(ir_node, partners, alloc_nodes[i]);
316 arch_set_irn_register(irn, reg);
317 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
318 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
322 /* Allocate the non-constrained Projs of the Perm. */
324 /* Put the colors of all Projs in a bitset. */
325 bitset_t *const bs = bitset_alloca(n_regs);
326 foreach_out_edge(perm, edge) {
327 ir_node *proj = get_edge_src_irn(edge);
328 const arch_register_t *reg = arch_get_irn_register(proj);
331 bitset_set(bs, reg->index);
334 /* Assign the not yet assigned Projs of the Perm a suitable color. */
335 foreach_out_edge(perm, edge) {
336 ir_node *proj = get_edge_src_irn(edge);
337 const arch_register_t *reg = arch_get_irn_register(proj);
339 DBG((dbg, LEVEL_2, "\tchecking reg of %+F: %s\n", proj, reg ? reg->name : "<none>"));
342 size_t const col = get_next_free_reg(alloc_env, bs);
343 reg = arch_register_for_index(env->cls, col);
344 bitset_set(bs, reg->index);
345 arch_set_irn_register(proj, reg);
346 pset_insert_ptr(alloc_env->pre_colored, proj);
347 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", proj, reg->name));
353 //hungarian_free(bp);
354 pmap_destroy(partners);
357 obstack_free(env->obst, base);
361 * Handle constraint nodes in each basic block.
362 * handle_constraints() inserts Perm nodes which perm
363 * over all values live at the constrained node right in front
364 * of the constrained node. These Perms signal a constrained node.
365 * For further comments, refer to handle_constraints().
367 static void constraints(ir_node *bl, void *data)
369 be_chordal_alloc_env_t *env = (be_chordal_alloc_env_t*)data;
372 for (irn = sched_first(bl); !sched_is_end(irn);) {
373 ir_node *const next = sched_next(irn);
374 handle_constraints(env, irn);
379 static void assign(ir_node *block, void *env_ptr)
381 be_chordal_alloc_env_t *alloc_env = (be_chordal_alloc_env_t*)env_ptr;
382 be_chordal_env_t *env = alloc_env->chordal_env;
383 bitset_t *live = alloc_env->live;
384 bitset_t *colors = alloc_env->colors;
385 struct list_head *head = get_block_border_head(env, block);
386 be_lv_t *lv = be_get_irg_liveness(env->irg);
388 bitset_clear_all(colors);
389 bitset_clear_all(live);
391 DBG((dbg, LEVEL_4, "Assigning colors for block %+F\n", block));
392 DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
393 foreach_border_head(head, b) {
394 DBG((dbg, LEVEL_4, "\t%s %+F/%d\n", b->is_def ? "def" : "use",
395 b->irn, get_irn_idx(b->irn)));
399 * Add initial defs for all values live in.
400 * Since their colors have already been assigned (The dominators were
401 * allocated before), we have to mark their colors as used also.
403 be_lv_foreach(lv, block, be_lv_state_in, irn) {
404 if (has_reg_class(env, irn)) {
405 const arch_register_t *reg = arch_get_irn_register(irn);
407 assert(reg && "Node must have been assigned a register");
408 DBG((dbg, LEVEL_4, "%+F has reg %s\n", irn, reg->name));
410 /* Mark the color of the live in value as used. */
411 int const col = reg->index;
412 bitset_set(colors, col);
414 /* Mark the value live in. */
415 bitset_set(live, get_irn_idx(irn));
420 * Mind that the sequence of defs from back to front defines a perfect
421 * elimination order. So, coloring the definitions from first to last
424 foreach_border_head(head, b) {
425 ir_node *irn = b->irn;
426 int nr = get_irn_idx(irn);
427 int ignore = arch_irn_is_ignore(irn);
430 * Assign a color, if it is a local def. Global defs already have a
433 if (b->is_def && !be_is_live_in(lv, block, irn)) {
434 const arch_register_t *reg;
437 if (ignore || pset_find_ptr(alloc_env->pre_colored, irn)) {
438 reg = arch_get_irn_register(irn);
440 assert(!bitset_is_set(colors, col) && "pre-colored register must be free");
442 col = get_next_free_reg(alloc_env, colors);
443 reg = arch_register_for_index(env->cls, col);
444 assert(arch_get_irn_register(irn) == NULL && "This node must not have been assigned a register yet");
447 bitset_set(colors, col);
448 arch_set_irn_register(irn, reg);
450 DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", reg->name, col, irn));
452 assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
453 bitset_set(live, nr);
454 } else if (!b->is_def) {
455 /* Clear the color upon a use. */
456 const arch_register_t *reg = arch_get_irn_register(irn);
458 assert(reg && "Register must have been assigned");
460 bitset_clear(colors, reg->index);
461 bitset_clear(live, nr);
466 static void be_ra_chordal_color(be_chordal_env_t *const chordal_env)
468 be_chordal_alloc_env_t env;
470 const arch_register_class_t *cls = chordal_env->cls;
472 int colors_n = arch_register_class_n_regs(cls);
473 ir_graph *irg = chordal_env->irg;
475 be_assure_live_sets(irg);
478 env.chordal_env = chordal_env;
479 env.colors_n = colors_n;
480 env.colors = bitset_alloca(colors_n);
481 env.tmp_colors = bitset_alloca(colors_n);
482 env.pre_colored = pset_new_ptr_default();
484 be_timer_push(T_SPLIT);
486 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPLIT) {
487 snprintf(buf, sizeof(buf), "%s-split", chordal_env->cls->name);
488 dump_ir_graph(chordal_env->irg, buf);
491 be_timer_pop(T_SPLIT);
493 be_timer_push(T_CONSTR);
495 /* Handle register targeting constraints */
496 dom_tree_walk_irg(irg, constraints, NULL, &env);
498 if (chordal_env->opts->dump_flags & BE_CH_DUMP_CONSTR) {
499 snprintf(buf, sizeof(buf), "%s-constr", chordal_env->cls->name);
500 dump_ir_graph(chordal_env->irg, buf);
503 be_timer_pop(T_CONSTR);
505 env.live = bitset_malloc(get_irg_last_idx(chordal_env->irg));
507 /* First, determine the pressure */
508 dom_tree_walk_irg(irg, create_borders, NULL, env.chordal_env);
510 /* Assign the colors */
511 dom_tree_walk_irg(irg, assign, NULL, &env);
513 if (chordal_env->opts->dump_flags & BE_CH_DUMP_TREE_INTV) {
515 ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
516 plotter = new_plotter_ps(buf);
517 draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
518 plotter_free(plotter);
521 bitset_free(env.live);
522 del_pset(env.pre_colored);
525 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal)
526 void be_init_chordal(void)
528 static be_ra_chordal_coloring_t coloring = {
531 FIRM_DBG_REGISTER(dbg, "firm.be.chordal");
533 be_register_chordal_coloring("default", &coloring);