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 #define DUMP_INTERVALS
71 typedef struct be_chordal_alloc_env_t {
72 be_chordal_env_t *chordal_env;
74 pset *pre_colored; /**< Set of precolored nodes. */
75 bitset_t *live; /**< A liveness bitset. */
76 bitset_t *tmp_colors; /**< An auxiliary bitset which is as long as the number of colors in the class. */
77 bitset_t *colors; /**< The color mask. */
78 bitset_t *in_colors; /**< Colors used by live in values. */
79 int colors_n; /**< The number of colors. */
80 } be_chordal_alloc_env_t;
82 static int get_next_free_reg(const be_chordal_alloc_env_t *alloc_env, bitset_t *colors)
84 bitset_t *tmp = alloc_env->tmp_colors;
85 bitset_copy(tmp, colors);
87 bitset_and(tmp, alloc_env->chordal_env->allocatable_regs);
88 return bitset_next_set(tmp, 0);
91 static bitset_t const *get_decisive_partner_regs(be_operand_t const *const o1)
93 be_operand_t const *const o2 = o1->partner;
94 assert(!o2 || o1->req->cls == o2->req->cls);
96 if (!o2 || bitset_contains(o1->regs, o2->regs)) {
98 } else if (bitset_contains(o2->regs, o1->regs)) {
105 static void pair_up_operands(const be_chordal_alloc_env_t *alloc_env, be_insn_t *insn)
107 const be_chordal_env_t *env = alloc_env->chordal_env;
108 bitset_t *bs = bitset_alloca(env->cls->n_regs);
113 * For each out operand, try to find an in operand which can be assigned the
114 * same register as the out operand.
116 for (j = 0; j < insn->use_start; ++j) {
117 be_operand_t *smallest = NULL;
118 int smallest_n_regs = env->cls->n_regs + 1;
119 be_operand_t *out_op = &insn->ops[j];
121 /* Try to find an in operand which has ... */
122 for (i = insn->use_start; i < insn->n_ops; ++i) {
124 be_operand_t *op = &insn->ops[i];
127 if (op->partner != NULL)
129 lv = be_get_irg_liveness(env->irg);
130 if (be_values_interfere(lv, op->irn, op->carrier))
133 bitset_copy(bs, op->regs);
134 bitset_and(bs, out_op->regs);
135 n_total = bitset_popcount(op->regs);
137 if (!bitset_is_empty(bs) && n_total < smallest_n_regs) {
139 smallest_n_regs = n_total;
143 if (smallest != NULL) {
144 for (i = insn->use_start; i < insn->n_ops; ++i) {
145 if (insn->ops[i].carrier == smallest->carrier)
146 insn->ops[i].partner = out_op;
149 out_op->partner = smallest;
150 smallest->partner = out_op;
155 static void handle_constraints(be_chordal_alloc_env_t *alloc_env,
159 ir_node **alloc_nodes;
160 //hungarian_problem_t *bp;
164 ir_node *perm = NULL;
165 //int match_res, cost;
166 be_chordal_env_t *env = alloc_env->chordal_env;
167 void *base = obstack_base(env->obst);
168 be_insn_t *insn = be_scan_insn(env, irn);
171 if (insn->pre_colored) {
173 for (i = 0; i < insn->use_start; ++i)
174 pset_insert_ptr(alloc_env->pre_colored, insn->ops[i].carrier);
178 * Perms inserted before the constraint handling phase are considered to be
179 * correctly precolored. These Perms arise during the ABI handling phase.
181 if (!insn->has_constraints || is_Phi(irn))
184 n_regs = env->cls->n_regs;
185 alloc_nodes = ALLOCAN(ir_node*, n_regs);
186 //bp = hungarian_new(n_regs, n_regs, 2, HUNGARIAN_MATCH_PERFECT);
187 bp = bipartite_new(n_regs, n_regs);
188 assignment = ALLOCAN(int, n_regs);
189 partners = pmap_create();
192 * prepare the constraint handling of this node.
193 * Perms are constructed and Copies are created for constrained values
194 * interfering with the instruction.
196 perm = pre_process_constraints(alloc_env->chordal_env, &insn);
198 /* find suitable in operands to the out operands of the node. */
199 pair_up_operands(alloc_env, insn);
202 * look at the in/out operands and add each operand (and its possible partner)
203 * to a bipartite graph (left: nodes with partners, right: admissible colors).
205 for (i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
206 be_operand_t *op = &insn->ops[i];
209 * If the operand has no partner or the partner has not been marked
210 * for allocation, determine the admissible registers and mark it
211 * for allocation by associating the node and its partner with the
212 * set of admissible registers via a bipartite graph.
214 if (!op->partner || !pmap_contains(partners, op->partner->carrier)) {
215 ir_node *partner = op->partner ? op->partner->carrier : NULL;
218 pmap_insert(partners, op->carrier, partner);
220 pmap_insert(partners, partner, op->carrier);
222 /* don't insert a node twice */
223 for (i = 0; i < n_alloc; ++i) {
224 if (alloc_nodes[i] == op->carrier) {
231 alloc_nodes[n_alloc] = op->carrier;
233 DBG((dbg, LEVEL_2, "\tassociating %+F and %+F\n", op->carrier,
236 bitset_t const *const bs = get_decisive_partner_regs(op);
238 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: %B\n", op->carrier, bs));
240 bitset_foreach(bs, col) {
241 //hungarian_add(bp, n_alloc, col, 1);
242 bipartite_add(bp, n_alloc, col);
245 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: none\n", op->carrier));
253 * Put all nodes which live through the constrained instruction also to the
254 * allocation bipartite graph. They are considered unconstrained.
257 foreach_out_edge(perm, edge) {
259 ir_node *proj = get_edge_src_irn(edge);
260 be_lv_t *lv = be_get_irg_liveness(env->irg);
262 assert(is_Proj(proj));
264 if (!be_values_interfere(lv, proj, irn)
265 || pmap_contains(partners, proj))
268 /* don't insert a node twice */
269 for (i = 0; i < n_alloc; ++i) {
270 if (alloc_nodes[i] == proj) {
278 assert(n_alloc < n_regs);
280 alloc_nodes[n_alloc] = proj;
281 pmap_insert(partners, proj, NULL);
283 bitset_foreach(env->allocatable_regs, col) {
284 //hungarian_add(bp, n_alloc, col, 1);
285 bipartite_add(bp, n_alloc, col);
292 /* Compute a valid register allocation. */
294 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
295 match_res = hungarian_solve(bp, assignment, &cost, 1);
296 assert(match_res == 0 && "matching failed");
298 /*bipartite_dump_f(stderr, bp);*/
299 bipartite_matching(bp, assignment);
302 /* Assign colors obtained from the matching. */
303 for (i = 0; i < n_alloc; ++i) {
304 const arch_register_t *reg;
307 assert(assignment[i] >= 0 && "there must have been a register assigned (node not register pressure faithful?)");
308 reg = arch_register_for_index(env->cls, assignment[i]);
310 irn = alloc_nodes[i];
312 arch_set_irn_register(irn, reg);
313 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
314 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
317 irn = pmap_get(ir_node, partners, alloc_nodes[i]);
319 arch_set_irn_register(irn, reg);
320 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
321 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
325 /* Allocate the non-constrained Projs of the Perm. */
327 /* Put the colors of all Projs in a bitset. */
328 bitset_t *const bs = bitset_alloca(n_regs);
329 foreach_out_edge(perm, edge) {
330 ir_node *proj = get_edge_src_irn(edge);
331 const arch_register_t *reg = arch_get_irn_register(proj);
334 bitset_set(bs, reg->index);
337 /* Assign the not yet assigned Projs of the Perm a suitable color. */
338 foreach_out_edge(perm, edge) {
339 ir_node *proj = get_edge_src_irn(edge);
340 const arch_register_t *reg = arch_get_irn_register(proj);
342 DBG((dbg, LEVEL_2, "\tchecking reg of %+F: %s\n", proj, reg ? reg->name : "<none>"));
345 size_t const col = get_next_free_reg(alloc_env, bs);
346 reg = arch_register_for_index(env->cls, col);
347 bitset_set(bs, reg->index);
348 arch_set_irn_register(proj, reg);
349 pset_insert_ptr(alloc_env->pre_colored, proj);
350 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", proj, reg->name));
356 //hungarian_free(bp);
357 pmap_destroy(partners);
360 obstack_free(env->obst, base);
364 * Handle constraint nodes in each basic block.
365 * handle_constraints() inserts Perm nodes which perm
366 * over all values live at the constrained node right in front
367 * of the constrained node. These Perms signal a constrained node.
368 * For further comments, refer to handle_constraints().
370 static void constraints(ir_node *bl, void *data)
372 be_chordal_alloc_env_t *env = (be_chordal_alloc_env_t*)data;
375 for (irn = sched_first(bl); !sched_is_end(irn);) {
376 ir_node *const next = sched_next(irn);
377 handle_constraints(env, irn);
382 static void assign(ir_node *block, void *env_ptr)
384 be_chordal_alloc_env_t *alloc_env = (be_chordal_alloc_env_t*)env_ptr;
385 be_chordal_env_t *env = alloc_env->chordal_env;
386 bitset_t *live = alloc_env->live;
387 bitset_t *colors = alloc_env->colors;
388 bitset_t *in_colors = alloc_env->in_colors;
389 struct list_head *head = get_block_border_head(env, block);
390 be_lv_t *lv = be_get_irg_liveness(env->irg);
392 bitset_clear_all(colors);
393 bitset_clear_all(live);
394 bitset_clear_all(in_colors);
396 DBG((dbg, LEVEL_4, "Assigning colors for block %+F\n", block));
397 DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
398 foreach_border_head(head, b) {
399 DBG((dbg, LEVEL_4, "\t%s %+F/%d\n", b->is_def ? "def" : "use",
400 b->irn, get_irn_idx(b->irn)));
404 * Add initial defs for all values live in.
405 * Since their colors have already been assigned (The dominators were
406 * allocated before), we have to mark their colors as used also.
408 be_lv_foreach(lv, block, be_lv_state_in, irn) {
409 if (has_reg_class(env, irn)) {
410 const arch_register_t *reg = arch_get_irn_register(irn);
412 assert(reg && "Node must have been assigned a register");
413 DBG((dbg, LEVEL_4, "%+F has reg %s\n", irn, reg->name));
415 /* Mark the color of the live in value as used. */
416 int const col = reg->index;
417 bitset_set(colors, col);
418 bitset_set(in_colors, col);
420 /* Mark the value live in. */
421 bitset_set(live, get_irn_idx(irn));
426 * Mind that the sequence of defs from back to front defines a perfect
427 * elimination order. So, coloring the definitions from first to last
430 foreach_border_head(head, b) {
431 ir_node *irn = b->irn;
432 int nr = get_irn_idx(irn);
433 int ignore = arch_irn_is_ignore(irn);
436 * Assign a color, if it is a local def. Global defs already have a
439 if (b->is_def && !be_is_live_in(lv, block, irn)) {
440 const arch_register_t *reg;
443 if (ignore || pset_find_ptr(alloc_env->pre_colored, irn)) {
444 reg = arch_get_irn_register(irn);
446 assert(!bitset_is_set(colors, col) && "pre-colored register must be free");
448 col = get_next_free_reg(alloc_env, colors);
449 reg = arch_register_for_index(env->cls, col);
450 assert(arch_get_irn_register(irn) == NULL && "This node must not have been assigned a register yet");
453 bitset_set(colors, col);
454 arch_set_irn_register(irn, reg);
456 DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", reg->name, col, irn));
458 assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
459 bitset_set(live, nr);
460 } else if (!b->is_def) {
461 /* Clear the color upon a use. */
462 const arch_register_t *reg = arch_get_irn_register(irn);
464 assert(reg && "Register must have been assigned");
466 bitset_clear(colors, reg->index);
467 bitset_clear(live, nr);
472 static void be_ra_chordal_color(be_chordal_env_t *const chordal_env)
474 be_chordal_alloc_env_t env;
476 const arch_register_class_t *cls = chordal_env->cls;
478 int colors_n = arch_register_class_n_regs(cls);
479 ir_graph *irg = chordal_env->irg;
481 be_assure_live_sets(irg);
484 env.chordal_env = chordal_env;
485 env.colors_n = colors_n;
486 env.colors = bitset_alloca(colors_n);
487 env.tmp_colors = bitset_alloca(colors_n);
488 env.in_colors = bitset_alloca(colors_n);
489 env.pre_colored = pset_new_ptr_default();
491 be_timer_push(T_SPLIT);
493 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPLIT) {
494 snprintf(buf, sizeof(buf), "%s-split", chordal_env->cls->name);
495 dump_ir_graph(chordal_env->irg, buf);
498 be_timer_pop(T_SPLIT);
500 be_timer_push(T_CONSTR);
502 /* Handle register targeting constraints */
503 dom_tree_walk_irg(irg, constraints, NULL, &env);
505 if (chordal_env->opts->dump_flags & BE_CH_DUMP_CONSTR) {
506 snprintf(buf, sizeof(buf), "%s-constr", chordal_env->cls->name);
507 dump_ir_graph(chordal_env->irg, buf);
510 be_timer_pop(T_CONSTR);
512 env.live = bitset_malloc(get_irg_last_idx(chordal_env->irg));
514 /* First, determine the pressure */
515 dom_tree_walk_irg(irg, create_borders, NULL, env.chordal_env);
517 /* Assign the colors */
518 dom_tree_walk_irg(irg, assign, NULL, &env);
520 if (chordal_env->opts->dump_flags & BE_CH_DUMP_TREE_INTV) {
522 ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
523 plotter = new_plotter_ps(buf);
524 draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
525 plotter_free(plotter);
528 bitset_free(env.live);
529 del_pset(env.pre_colored);
532 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal)
533 void be_init_chordal(void)
535 static be_ra_chordal_coloring_t coloring = {
538 FIRM_DBG_REGISTER(dbg, "firm.be.chordal");
540 be_register_chordal_coloring("default", &coloring);