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);
91 bitset_or(tmp, alloc_env->chordal_env->ignore_colors);
92 return bitset_next_clear(tmp, 0);
95 static bitset_t *get_decisive_partner_regs(bitset_t *bs, const be_operand_t *o1, const be_operand_t *o2)
100 bitset_copy(bs, o2->regs);
105 bitset_copy(bs, o1->regs);
109 assert(o1->req->cls == o2->req->cls || ! o1->req->cls || ! o2->req->cls);
111 if (bitset_contains(o1->regs, o2->regs)) {
112 bitset_copy(bs, o1->regs);
113 } else if (bitset_contains(o2->regs, o1->regs)) {
114 bitset_copy(bs, o2->regs);
122 static void pair_up_operands(const be_chordal_alloc_env_t *alloc_env, be_insn_t *insn)
124 const be_chordal_env_t *env = alloc_env->chordal_env;
125 bitset_t *bs = bitset_alloca(env->cls->n_regs);
130 * For each out operand, try to find an in operand which can be assigned the
131 * same register as the out operand.
133 for (j = 0; j < insn->use_start; ++j) {
134 be_operand_t *smallest = NULL;
135 int smallest_n_regs = env->cls->n_regs + 1;
136 be_operand_t *out_op = &insn->ops[j];
138 /* Try to find an in operand which has ... */
139 for (i = insn->use_start; i < insn->n_ops; ++i) {
141 be_operand_t *op = &insn->ops[i];
144 if (op->partner != NULL)
146 lv = be_get_irg_liveness(env->irg);
147 if (be_values_interfere(lv, op->irn, op->carrier))
150 bitset_copy(bs, op->regs);
151 bitset_and(bs, out_op->regs);
152 n_total = bitset_popcount(op->regs);
154 if (!bitset_is_empty(bs) && n_total < smallest_n_regs) {
156 smallest_n_regs = n_total;
160 if (smallest != NULL) {
161 for (i = insn->use_start; i < insn->n_ops; ++i) {
162 if (insn->ops[i].carrier == smallest->carrier)
163 insn->ops[i].partner = out_op;
166 out_op->partner = smallest;
167 smallest->partner = out_op;
172 static ir_node *handle_constraints(be_chordal_alloc_env_t *alloc_env,
173 ir_node *irn, int *silent)
177 ir_node **alloc_nodes;
178 //hungarian_problem_t *bp;
183 const ir_edge_t *edge;
184 ir_node *perm = NULL;
185 //int match_res, cost;
186 be_chordal_env_t *env = alloc_env->chordal_env;
187 void *base = obstack_base(env->obst);
188 be_insn_t *insn = chordal_scan_insn(env, irn);
189 ir_node *res = insn->next_insn;
190 int be_silent = *silent;
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 * If the current node is a barrier toggle the silent flag.
201 * If we are in the start block, we are ought to be silent at the beginning,
202 * so the toggling activates the constraint handling but skips the barrier.
203 * If we are in the end block we handle the in requirements of the barrier
204 * and set the rest to silent.
206 if (be_is_Barrier(irn))
213 * Perms inserted before the constraint handling phase are considered to be
214 * correctly precolored. These Perms arise during the ABI handling phase.
216 if (!insn->has_constraints)
219 n_regs = env->cls->n_regs;
220 bs = bitset_alloca(n_regs);
221 alloc_nodes = ALLOCAN(ir_node*, n_regs);
222 //bp = hungarian_new(n_regs, n_regs, 2, HUNGARIAN_MATCH_PERFECT);
223 bp = bipartite_new(n_regs, n_regs);
224 assignment = ALLOCAN(int, n_regs);
225 partners = pmap_create();
228 * prepare the constraint handling of this node.
229 * Perms are constructed and Copies are created for constrained values
230 * interfering with the instruction.
232 perm = pre_process_constraints(alloc_env->chordal_env, &insn);
234 /* find suitable in operands to the out operands of the node. */
235 pair_up_operands(alloc_env, insn);
238 * look at the in/out operands and add each operand (and its possible partner)
239 * to a bipartite graph (left: nodes with partners, right: admissible colors).
241 for (i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
242 be_operand_t *op = &insn->ops[i];
245 * If the operand has no partner or the partner has not been marked
246 * for allocation, determine the admissible registers and mark it
247 * for allocation by associating the node and its partner with the
248 * set of admissible registers via a bipartite graph.
250 if (!op->partner || !pmap_contains(partners, op->partner->carrier)) {
251 ir_node *partner = op->partner ? op->partner->carrier : NULL;
254 pmap_insert(partners, op->carrier, partner);
256 pmap_insert(partners, partner, op->carrier);
258 /* don't insert a node twice */
259 for (i = 0; i < n_alloc; ++i) {
260 if (alloc_nodes[i] == op->carrier) {
267 alloc_nodes[n_alloc] = op->carrier;
269 DBG((dbg, LEVEL_2, "\tassociating %+F and %+F\n", op->carrier,
272 bitset_clear_all(bs);
273 get_decisive_partner_regs(bs, op, op->partner);
275 DBG((dbg, LEVEL_2, "\tallowed registers for %+F: %B\n", op->carrier,
278 bitset_foreach(bs, col) {
279 //hungarian_add(bp, n_alloc, col, 1);
280 bipartite_add(bp, n_alloc, col);
288 * Put all nodes which live through the constrained instruction also to the
289 * allocation bipartite graph. They are considered unconstrained.
292 foreach_out_edge(perm, edge) {
294 ir_node *proj = get_edge_src_irn(edge);
295 be_lv_t *lv = be_get_irg_liveness(env->irg);
297 assert(is_Proj(proj));
299 if (!be_values_interfere(lv, proj, irn)
300 || pmap_contains(partners, proj))
303 /* don't insert a node twice */
304 for (i = 0; i < n_alloc; ++i) {
305 if (alloc_nodes[i] == proj) {
313 assert(n_alloc < n_regs);
315 alloc_nodes[n_alloc] = proj;
316 pmap_insert(partners, proj, NULL);
318 bitset_clear_all(bs);
319 arch_put_non_ignore_regs(env->cls, bs);
320 bitset_andnot(bs, env->ignore_colors);
321 bitset_foreach(bs, col) {
322 //hungarian_add(bp, n_alloc, col, 1);
323 bipartite_add(bp, n_alloc, col);
330 /* Compute a valid register allocation. */
332 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
333 match_res = hungarian_solve(bp, assignment, &cost, 1);
334 assert(match_res == 0 && "matching failed");
336 /*bipartite_dump_f(stderr, bp);*/
337 bipartite_matching(bp, assignment);
340 /* Assign colors obtained from the matching. */
341 for (i = 0; i < n_alloc; ++i) {
342 const arch_register_t *reg;
345 assert(assignment[i] >= 0 && "there must have been a register assigned (node not register pressure faithful?)");
346 reg = arch_register_for_index(env->cls, assignment[i]);
347 assert(! (reg->type & arch_register_type_ignore));
349 irn = alloc_nodes[i];
351 arch_set_irn_register(irn, reg);
352 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
353 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
356 irn = pmap_get(partners, alloc_nodes[i]);
358 arch_set_irn_register(irn, reg);
359 (void) pset_hinsert_ptr(alloc_env->pre_colored, irn);
360 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", irn, reg->name));
364 /* Allocate the non-constrained Projs of the Perm. */
366 bitset_clear_all(bs);
368 /* Put the colors of all Projs in a bitset. */
369 foreach_out_edge(perm, edge) {
370 ir_node *proj = get_edge_src_irn(edge);
371 const arch_register_t *reg = arch_get_irn_register(proj);
374 bitset_set(bs, reg->index);
377 /* Assign the not yet assigned Projs of the Perm a suitable color. */
378 foreach_out_edge(perm, edge) {
379 ir_node *proj = get_edge_src_irn(edge);
380 const arch_register_t *reg = arch_get_irn_register(proj);
382 DBG((dbg, LEVEL_2, "\tchecking reg of %+F: %s\n", proj, reg ? reg->name : "<none>"));
385 col = get_next_free_reg(alloc_env, bs);
386 reg = arch_register_for_index(env->cls, col);
387 bitset_set(bs, reg->index);
388 arch_set_irn_register(proj, reg);
389 pset_insert_ptr(alloc_env->pre_colored, proj);
390 DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", proj, reg->name));
396 //hungarian_free(bp);
397 pmap_destroy(partners);
400 obstack_free(env->obst, base);
405 * Handle constraint nodes in each basic block.
406 * handle_constraints() inserts Perm nodes which perm
407 * over all values live at the constrained node right in front
408 * of the constrained node. These Perms signal a constrained node.
409 * For further comments, refer to handle_constraints().
411 static void constraints(ir_node *bl, void *data)
414 * Start silent in the start block.
415 * The silence remains until the first barrier is seen.
416 * Each other block is begun loud.
418 int silent = bl == get_irg_start_block(get_irn_irg(bl));
419 be_chordal_alloc_env_t *env = data;
423 * If the block is the start block search the barrier and
424 * start handling constraints from there.
426 for (irn = sched_first(bl); !sched_is_end(irn);) {
427 irn = handle_constraints(env, irn, &silent);
431 static void assign(ir_node *block, void *env_ptr)
433 be_chordal_alloc_env_t *alloc_env = env_ptr;
434 be_chordal_env_t *env = alloc_env->chordal_env;
435 bitset_t *live = alloc_env->live;
436 bitset_t *colors = alloc_env->colors;
437 bitset_t *in_colors = alloc_env->in_colors;
438 struct list_head *head = get_block_border_head(env, block);
439 be_lv_t *lv = be_get_irg_liveness(env->irg);
445 bitset_clear_all(colors);
446 bitset_clear_all(live);
447 bitset_clear_all(in_colors);
449 DBG((dbg, LEVEL_4, "Assigning colors for block %+F\n", block));
450 DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
451 list_for_each_entry(border_t, b, head, list) {
452 DBG((dbg, LEVEL_4, "\t%s %+F/%d\n", b->is_def ? "def" : "use",
453 b->irn, get_irn_idx(b->irn)));
457 * Add initial defs for all values live in.
458 * Since their colors have already been assigned (The dominators were
459 * allocated before), we have to mark their colors as used also.
461 be_lv_foreach(lv, block, be_lv_state_in, idx) {
462 irn = be_lv_get_irn(lv, block, idx);
463 if (has_reg_class(env, irn)) {
464 const arch_register_t *reg = arch_get_irn_register(irn);
467 assert(reg && "Node must have been assigned a register");
468 col = arch_register_get_index(reg);
470 DBG((dbg, LEVEL_4, "%+F has reg %s\n", irn, reg->name));
472 /* Mark the color of the live in value as used. */
473 bitset_set(colors, col);
474 bitset_set(in_colors, col);
476 /* Mark the value live in. */
477 bitset_set(live, get_irn_idx(irn));
482 * Mind that the sequence of defs from back to front defines a perfect
483 * elimination order. So, coloring the definitions from first to last
486 list_for_each_entry_reverse(border_t, b, head, list) {
487 ir_node *irn = b->irn;
488 int nr = get_irn_idx(irn);
489 int ignore = arch_irn_is_ignore(irn);
492 * Assign a color, if it is a local def. Global defs already have a
495 if (b->is_def && !be_is_live_in(lv, block, irn)) {
496 const arch_register_t *reg;
499 if (ignore || pset_find_ptr(alloc_env->pre_colored, irn)) {
500 reg = arch_get_irn_register(irn);
502 assert(!bitset_is_set(colors, col) && "pre-colored register must be free");
504 col = get_next_free_reg(alloc_env, colors);
505 reg = arch_register_for_index(env->cls, col);
506 assert(arch_get_irn_register(irn) == NULL && "This node must not have been assigned a register yet");
507 assert(!arch_register_type_is(reg, ignore) && "Must not assign ignore register");
510 bitset_set(colors, col);
511 arch_set_irn_register(irn, reg);
513 DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", arch_register_get_name(reg), col, irn));
515 assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
516 bitset_set(live, nr);
517 } else if (!b->is_def) {
518 /* Clear the color upon a use. */
519 const arch_register_t *reg = arch_get_irn_register(irn);
522 assert(reg && "Register must have been assigned");
524 col = arch_register_get_index(reg);
526 if (!arch_register_type_is(reg, ignore)) {
527 assert(bitset_is_set(live, nr) && "Cannot have a non live use");
531 bitset_clear(colors, col);
532 bitset_clear(live, nr);
537 void be_ra_chordal_color(be_chordal_env_t *chordal_env)
539 be_chordal_alloc_env_t env;
542 const arch_register_class_t *cls = chordal_env->cls;
544 int colors_n = arch_register_class_n_regs(cls);
545 ir_graph *irg = chordal_env->irg;
547 lv = be_assure_liveness(irg);
548 be_liveness_assure_sets(lv);
549 be_liveness_assure_chk(lv);
553 env.chordal_env = chordal_env;
554 env.colors_n = colors_n;
555 env.colors = bitset_alloca(colors_n);
556 env.tmp_colors = bitset_alloca(colors_n);
557 env.in_colors = bitset_alloca(colors_n);
558 env.pre_colored = pset_new_ptr_default();
560 be_timer_push(T_CONSTR);
562 /* Handle register targeting constraints */
563 dom_tree_walk_irg(irg, constraints, NULL, &env);
565 if (chordal_env->opts->dump_flags & BE_CH_DUMP_CONSTR) {
566 snprintf(buf, sizeof(buf), "%s-constr", chordal_env->cls->name);
567 dump_ir_graph(chordal_env->irg, buf);
570 be_timer_pop(T_CONSTR);
572 env.live = bitset_malloc(get_irg_last_idx(chordal_env->irg));
574 /* First, determine the pressure */
575 dom_tree_walk_irg(irg, create_borders, NULL, env.chordal_env);
577 /* Assign the colors */
578 dom_tree_walk_irg(irg, assign, NULL, &env);
580 if (chordal_env->opts->dump_flags & BE_CH_DUMP_TREE_INTV) {
582 ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
583 plotter = new_plotter_ps(buf);
584 draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
585 plotter_free(plotter);
588 bitset_free(env.live);
589 del_pset(env.pre_colored);
592 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal);
593 void be_init_chordal(void)
595 static be_ra_chordal_coloring_t coloring = {
598 FIRM_DBG_REGISTER(dbg, "firm.be.chordal");
600 be_register_chordal_coloring("default", &coloring);