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 } be_chordal_alloc_env_t;
78 static int get_next_free_reg(const be_chordal_alloc_env_t *alloc_env, bitset_t *colors)
80 bitset_t *tmp = alloc_env->tmp_colors;
81 bitset_copy(tmp, colors);
83 bitset_and(tmp, alloc_env->chordal_env->allocatable_regs);
84 return bitset_next_set(tmp, 0);
87 static bitset_t const *get_decisive_partner_regs(be_operand_t const *const o1)
89 be_operand_t const *const o2 = o1->partner;
90 assert(!o2 || o1->req->cls == o2->req->cls);
92 if (!o2 || bitset_contains(o1->regs, o2->regs)) {
94 } else if (bitset_contains(o2->regs, o1->regs)) {
101 static void pair_up_operands(const be_chordal_alloc_env_t *alloc_env, be_insn_t *insn)
103 const be_chordal_env_t *env = alloc_env->chordal_env;
104 bitset_t *bs = bitset_alloca(env->cls->n_regs);
109 * For each out operand, try to find an in operand which can be assigned the
110 * same register as the out operand.
112 for (j = 0; j < insn->use_start; ++j) {
113 be_operand_t *smallest = NULL;
114 int smallest_n_regs = env->cls->n_regs + 1;
115 be_operand_t *out_op = &insn->ops[j];
117 /* Try to find an in operand which has ... */
118 for (i = insn->use_start; i < insn->n_ops; ++i) {
120 be_operand_t *op = &insn->ops[i];
123 if (op->partner != NULL)
125 lv = be_get_irg_liveness(env->irg);
126 if (be_values_interfere(lv, op->irn, op->carrier))
129 bitset_copy(bs, op->regs);
130 bitset_and(bs, out_op->regs);
131 n_total = bitset_popcount(op->regs);
133 if (!bitset_is_empty(bs) && n_total < smallest_n_regs) {
135 smallest_n_regs = n_total;
139 if (smallest != NULL) {
140 for (i = insn->use_start; i < insn->n_ops; ++i) {
141 if (insn->ops[i].carrier == smallest->carrier)
142 insn->ops[i].partner = out_op;
145 out_op->partner = smallest;
146 smallest->partner = out_op;
151 static void handle_constraints(be_chordal_alloc_env_t *alloc_env,
155 ir_node **alloc_nodes;
156 //hungarian_problem_t *bp;
160 ir_node *perm = NULL;
161 //int match_res, cost;
162 be_chordal_env_t *env = alloc_env->chordal_env;
163 void *base = obstack_base(env->obst);
164 be_insn_t *insn = be_scan_insn(env, irn);
167 if (insn->pre_colored) {
169 for (i = 0; i < insn->use_start; ++i)
170 pset_insert_ptr(alloc_env->pre_colored, insn->ops[i].carrier);
174 * Perms inserted before the constraint handling phase are considered to be
175 * correctly precolored. These Perms arise during the ABI handling phase.
177 if (!insn->has_constraints || is_Phi(irn))
180 n_regs = env->cls->n_regs;
181 alloc_nodes = ALLOCAN(ir_node*, n_regs);
182 //bp = hungarian_new(n_regs, n_regs, 2, HUNGARIAN_MATCH_PERFECT);
183 bp = bipartite_new(n_regs, n_regs);
184 assignment = ALLOCAN(int, n_regs);
185 partners = pmap_create();
188 * prepare the constraint handling of this node.
189 * Perms are constructed and Copies are created for constrained values
190 * interfering with the instruction.
192 perm = pre_process_constraints(alloc_env->chordal_env, &insn);
194 /* find suitable in operands to the out operands of the node. */
195 pair_up_operands(alloc_env, insn);
198 * look at the in/out operands and add each operand (and its possible partner)
199 * to a bipartite graph (left: nodes with partners, right: admissible colors).
201 for (i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
202 be_operand_t *op = &insn->ops[i];
205 * If the operand has no partner or the partner has not been marked
206 * for allocation, determine the admissible registers and mark it
207 * for allocation by associating the node and its partner with the
208 * set of admissible registers via a bipartite graph.
210 if (!op->partner || !pmap_contains(partners, op->partner->carrier)) {
211 ir_node *partner = op->partner ? op->partner->carrier : NULL;
214 pmap_insert(partners, op->carrier, partner);
216 pmap_insert(partners, partner, op->carrier);
218 /* don't insert a node twice */
219 for (i = 0; i < n_alloc; ++i) {
220 if (alloc_nodes[i] == op->carrier) {
227 alloc_nodes[n_alloc] = op->carrier;
229 DBG((dbg, LEVEL_2, "\tassociating %+F and %+F\n", op->carrier,
232 bitset_t const *const bs = get_decisive_partner_regs(op);
234 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: %B\n", op->carrier, bs));
236 bitset_foreach(bs, col) {
237 //hungarian_add(bp, n_alloc, col, 1);
238 bipartite_add(bp, n_alloc, col);
241 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: none\n", op->carrier));
249 * Put all nodes which live through the constrained instruction also to the
250 * allocation bipartite graph. They are considered unconstrained.
253 foreach_out_edge(perm, edge) {
255 ir_node *proj = get_edge_src_irn(edge);
256 be_lv_t *lv = be_get_irg_liveness(env->irg);
258 assert(is_Proj(proj));
260 if (!be_values_interfere(lv, proj, irn)
261 || pmap_contains(partners, proj))
264 /* don't insert a node twice */
265 for (i = 0; i < n_alloc; ++i) {
266 if (alloc_nodes[i] == proj) {
274 assert(n_alloc < n_regs);
276 alloc_nodes[n_alloc] = proj;
277 pmap_insert(partners, proj, NULL);
279 bitset_foreach(env->allocatable_regs, col) {
280 //hungarian_add(bp, n_alloc, col, 1);
281 bipartite_add(bp, n_alloc, col);
288 /* Compute a valid register allocation. */
290 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
291 match_res = hungarian_solve(bp, assignment, &cost, 1);
292 assert(match_res == 0 && "matching failed");
294 /*bipartite_dump_f(stderr, bp);*/
295 bipartite_matching(bp, assignment);
298 /* Assign colors obtained from the matching. */
299 for (i = 0; i < n_alloc; ++i) {
300 const arch_register_t *reg;
303 assert(assignment[i] >= 0 && "there must have been a register assigned (node not register pressure faithful?)");
304 reg = arch_register_for_index(env->cls, assignment[i]);
306 irn = alloc_nodes[i];
308 arch_set_irn_register(irn, reg);
309 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
310 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
313 irn = pmap_get(ir_node, partners, alloc_nodes[i]);
315 arch_set_irn_register(irn, reg);
316 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
317 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
321 /* Allocate the non-constrained Projs of the Perm. */
323 /* Put the colors of all Projs in a bitset. */
324 bitset_t *const bs = bitset_alloca(n_regs);
325 foreach_out_edge(perm, edge) {
326 ir_node *proj = get_edge_src_irn(edge);
327 const arch_register_t *reg = arch_get_irn_register(proj);
330 bitset_set(bs, reg->index);
333 /* Assign the not yet assigned Projs of the Perm a suitable color. */
334 foreach_out_edge(perm, edge) {
335 ir_node *proj = get_edge_src_irn(edge);
336 const arch_register_t *reg = arch_get_irn_register(proj);
338 DBG((dbg, LEVEL_2, "\tchecking reg of %+F: %s\n", proj, reg ? reg->name : "<none>"));
341 size_t const col = get_next_free_reg(alloc_env, bs);
342 reg = arch_register_for_index(env->cls, col);
343 bitset_set(bs, reg->index);
344 arch_set_irn_register(proj, reg);
345 pset_insert_ptr(alloc_env->pre_colored, proj);
346 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", proj, reg->name));
352 //hungarian_free(bp);
353 pmap_destroy(partners);
356 obstack_free(env->obst, base);
360 * Handle constraint nodes in each basic block.
361 * handle_constraints() inserts Perm nodes which perm
362 * over all values live at the constrained node right in front
363 * of the constrained node. These Perms signal a constrained node.
364 * For further comments, refer to handle_constraints().
366 static void constraints(ir_node *bl, void *data)
368 be_chordal_alloc_env_t *env = (be_chordal_alloc_env_t*)data;
371 for (irn = sched_first(bl); !sched_is_end(irn);) {
372 ir_node *const next = sched_next(irn);
373 handle_constraints(env, irn);
378 static void assign(ir_node *block, void *env_ptr)
380 be_chordal_alloc_env_t *alloc_env = (be_chordal_alloc_env_t*)env_ptr;
381 be_chordal_env_t *env = alloc_env->chordal_env;
382 bitset_t *live = alloc_env->live;
383 bitset_t *colors = alloc_env->colors;
384 struct list_head *head = get_block_border_head(env, block);
385 be_lv_t *lv = be_get_irg_liveness(env->irg);
387 bitset_clear_all(colors);
388 bitset_clear_all(live);
390 DBG((dbg, LEVEL_4, "Assigning colors for block %+F\n", block));
391 DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
392 foreach_border_head(head, b) {
393 DBG((dbg, LEVEL_4, "\t%s %+F/%d\n", b->is_def ? "def" : "use",
394 b->irn, get_irn_idx(b->irn)));
398 * Add initial defs for all values live in.
399 * Since their colors have already been assigned (The dominators were
400 * allocated before), we have to mark their colors as used also.
402 be_lv_foreach(lv, block, be_lv_state_in, irn) {
403 if (arch_irn_consider_in_reg_alloc(env->cls, irn)) {
404 const arch_register_t *reg = arch_get_irn_register(irn);
406 assert(reg && "Node must have been assigned a register");
407 DBG((dbg, LEVEL_4, "%+F has reg %s\n", irn, reg->name));
409 /* Mark the color of the live in value as used. */
410 int const col = reg->index;
411 bitset_set(colors, col);
413 /* Mark the value live in. */
414 bitset_set(live, get_irn_idx(irn));
419 * Mind that the sequence of defs from back to front defines a perfect
420 * elimination order. So, coloring the definitions from first to last
423 foreach_border_head(head, b) {
424 ir_node *irn = b->irn;
425 int nr = get_irn_idx(irn);
426 int ignore = arch_irn_is_ignore(irn);
429 * Assign a color, if it is a local def. Global defs already have a
432 if (b->is_def && !be_is_live_in(lv, block, irn)) {
433 const arch_register_t *reg;
436 if (ignore || pset_find_ptr(alloc_env->pre_colored, irn)) {
437 reg = arch_get_irn_register(irn);
439 assert(!bitset_is_set(colors, col) && "pre-colored register must be free");
441 col = get_next_free_reg(alloc_env, colors);
442 reg = arch_register_for_index(env->cls, col);
443 assert(arch_get_irn_register(irn) == NULL && "This node must not have been assigned a register yet");
446 bitset_set(colors, col);
447 arch_set_irn_register(irn, reg);
449 DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", reg->name, col, irn));
451 assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
452 bitset_set(live, nr);
453 } else if (!b->is_def) {
454 /* Clear the color upon a use. */
455 const arch_register_t *reg = arch_get_irn_register(irn);
457 assert(reg && "Register must have been assigned");
459 bitset_clear(colors, reg->index);
460 bitset_clear(live, nr);
465 static void be_ra_chordal_color(be_chordal_env_t *const chordal_env)
467 be_chordal_alloc_env_t env;
469 const arch_register_class_t *cls = chordal_env->cls;
471 int colors_n = arch_register_class_n_regs(cls);
472 ir_graph *irg = chordal_env->irg;
474 be_assure_live_sets(irg);
477 env.chordal_env = chordal_env;
478 env.colors = bitset_alloca(colors_n);
479 env.tmp_colors = bitset_alloca(colors_n);
480 env.pre_colored = pset_new_ptr_default();
482 be_timer_push(T_SPLIT);
484 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPLIT) {
485 snprintf(buf, sizeof(buf), "%s-split", chordal_env->cls->name);
486 dump_ir_graph(chordal_env->irg, buf);
489 be_timer_pop(T_SPLIT);
491 be_timer_push(T_CONSTR);
493 /* Handle register targeting constraints */
494 dom_tree_walk_irg(irg, constraints, NULL, &env);
496 if (chordal_env->opts->dump_flags & BE_CH_DUMP_CONSTR) {
497 snprintf(buf, sizeof(buf), "%s-constr", chordal_env->cls->name);
498 dump_ir_graph(chordal_env->irg, buf);
501 be_timer_pop(T_CONSTR);
503 env.live = bitset_malloc(get_irg_last_idx(chordal_env->irg));
505 /* First, determine the pressure */
506 dom_tree_walk_irg(irg, create_borders, NULL, env.chordal_env);
508 /* Assign the colors */
509 dom_tree_walk_irg(irg, assign, NULL, &env);
511 if (chordal_env->opts->dump_flags & BE_CH_DUMP_TREE_INTV) {
513 ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
514 plotter = new_plotter_ps(buf);
515 draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
516 plotter_free(plotter);
519 bitset_free(env.live);
520 del_pset(env.pre_colored);
523 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal)
524 void be_init_chordal(void)
526 static be_ra_chordal_coloring_t coloring = {
529 FIRM_DBG_REGISTER(dbg, "firm.be.chordal");
531 be_register_chordal_coloring("default", &coloring);