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 Implements a trace scheduler as presented in Muchnik[TM].
23 * @author Michael Beck
31 #include "iredges_t.h"
34 #include "belistsched.h"
38 /* we need a special mark */
42 typedef struct trace_irn {
43 sched_timestep_t delay; /**< The delay for this node if already calculated, else 0. */
44 sched_timestep_t etime; /**< The earliest time of this node. */
45 unsigned num_user; /**< The number real users (mode datab) of this node */
46 int reg_diff; /**< The difference of num(out registers) - num(in registers) */
47 int preorder; /**< The pre-order position */
48 unsigned critical_path_len; /**< The weighted length of the longest critical path */
49 unsigned is_root : 1; /**< is a root node of a block */
52 typedef struct trace_env {
53 trace_irn_t *sched_info; /**< trace scheduling information about the nodes */
54 sched_timestep_t curr_time; /**< current time of the scheduler */
55 void *selector_env; /**< the backend selector environment */
56 const list_sched_selector_t *selector; /**< the actual backend selector */
57 be_lv_t *liveness; /**< The liveness for the irg */
58 DEBUG_ONLY(firm_dbg_module_t *dbg;)
62 * Returns a random node from a nodeset
64 static ir_node *get_nodeset_node(const ir_nodeset_t *nodeset)
66 ir_nodeset_iterator_t iter;
68 ir_nodeset_iterator_init(&iter, nodeset);
69 return ir_nodeset_iterator_next(&iter);
73 * Returns non-zero if the node is a root node
75 static inline unsigned is_root_node(trace_env_t *env, ir_node *n)
77 int idx = get_irn_idx(n);
79 assert(idx < ARR_LEN(env->sched_info));
80 return env->sched_info[idx].is_root;
84 * Mark a node as root node
86 static inline void mark_root_node(trace_env_t *env, ir_node *n)
88 int idx = get_irn_idx(n);
90 assert(idx < ARR_LEN(env->sched_info));
91 env->sched_info[idx].is_root = 1;
95 * Get the current delay.
97 static inline sched_timestep_t get_irn_delay(trace_env_t *env, ir_node *n)
99 int idx = get_irn_idx(n);
101 assert(idx < ARR_LEN(env->sched_info));
102 return env->sched_info[idx].delay;
106 * Set the current delay.
108 static inline void set_irn_delay(trace_env_t *env, ir_node *n, sched_timestep_t delay)
110 int idx = get_irn_idx(n);
112 assert(idx < ARR_LEN(env->sched_info));
113 env->sched_info[idx].delay = delay;
117 * Get the current etime.
119 static inline sched_timestep_t get_irn_etime(trace_env_t *env, ir_node *n)
121 int idx = get_irn_idx(n);
123 assert(idx < ARR_LEN(env->sched_info));
124 return env->sched_info[idx].etime;
128 * Set the current etime.
130 static inline void set_irn_etime(trace_env_t *env, ir_node *n, sched_timestep_t etime)
132 int idx = get_irn_idx(n);
134 assert(idx < ARR_LEN(env->sched_info));
135 env->sched_info[idx].etime = etime;
139 * Get the number of users.
141 static inline unsigned get_irn_num_user(trace_env_t *env, ir_node *n)
143 int idx = get_irn_idx(n);
145 assert(idx < ARR_LEN(env->sched_info));
146 return env->sched_info[idx].num_user;
150 * Set the number of users.
152 static inline void set_irn_num_user(trace_env_t *env, ir_node *n, unsigned num_user)
154 int idx = get_irn_idx(n);
156 assert(idx < ARR_LEN(env->sched_info));
157 env->sched_info[idx].num_user = num_user;
161 * Get the register difference.
163 static inline int get_irn_reg_diff(trace_env_t *env, ir_node *n)
165 int idx = get_irn_idx(n);
167 assert(idx < ARR_LEN(env->sched_info));
168 return env->sched_info[idx].reg_diff;
172 * Set the register difference.
174 static inline void set_irn_reg_diff(trace_env_t *env, ir_node *n, int reg_diff)
176 int idx = get_irn_idx(n);
178 assert(idx < ARR_LEN(env->sched_info));
179 env->sched_info[idx].reg_diff = reg_diff;
183 * Get the pre-order position.
185 static inline int get_irn_preorder(trace_env_t *env, ir_node *n)
187 int idx = get_irn_idx(n);
189 assert(idx < ARR_LEN(env->sched_info));
190 return env->sched_info[idx].preorder;
194 * Set the pre-order position.
196 static inline void set_irn_preorder(trace_env_t *env, ir_node *n, int pos)
198 int idx = get_irn_idx(n);
200 assert(idx < ARR_LEN(env->sched_info));
201 env->sched_info[idx].preorder = pos;
205 * Get the pre-order position.
207 static inline unsigned get_irn_critical_path_len(trace_env_t *env, ir_node *n)
209 int idx = get_irn_idx(n);
211 assert(idx < ARR_LEN(env->sched_info));
212 return env->sched_info[idx].critical_path_len;
216 * Set the pre-order position.
218 static inline void set_irn_critical_path_len(trace_env_t *env, ir_node *n, unsigned len)
220 int idx = get_irn_idx(n);
222 assert(idx < ARR_LEN(env->sched_info));
223 env->sched_info[idx].critical_path_len = len;
227 * returns the exec-time for node n.
229 static sched_timestep_t exectime(trace_env_t *env, ir_node *n)
231 if (be_is_Keep(n) || is_Proj(n))
233 if (env->selector->exectime)
234 return env->selector->exectime(env->selector_env, n);
239 * Calculates the latency for between two ops
241 static sched_timestep_t latency(trace_env_t *env, ir_node *pred, int pred_cycle, ir_node *curr, int curr_cycle)
243 /* a Keep hides a root */
244 if (be_is_Keep(curr))
245 return exectime(env, pred);
247 /* Proj's are executed immediately */
251 /* predecessors Proj's must be skipped */
253 pred = get_Proj_pred(pred);
255 if (env->selector->latency)
256 return env->selector->latency(env->selector_env, pred, pred_cycle, curr, curr_cycle);
261 * Returns the number of users of a node having mode datab.
263 static int get_num_successors(ir_node *irn)
266 const ir_edge_t *edge;
268 if (get_irn_mode(irn) == mode_T) {
269 /* for mode_T nodes: count the users of all Projs */
270 foreach_out_edge(irn, edge) {
271 ir_node *proj = get_edge_src_irn(edge);
272 ir_mode *mode = get_irn_mode(proj);
275 sum += get_num_successors(proj);
276 else if (mode_is_datab(mode))
277 sum += get_irn_n_edges(proj);
281 /* do not count keep-alive edges */
282 foreach_out_edge(irn, edge) {
283 if (get_irn_opcode(get_edge_src_irn(edge)) != iro_End)
292 * Returns the difference of regs_output - regs_input;
294 static int get_reg_difference(trace_env_t *env, ir_node *irn)
299 ir_node *block = get_nodes_block(irn);
301 if (be_is_Call(irn)) {
302 /* we want calls preferred */
306 if (get_irn_mode(irn) == mode_T) {
307 /* mode_T nodes: num out regs == num Projs with mode datab */
308 const ir_edge_t *edge;
309 foreach_out_edge(irn, edge) {
310 ir_node *proj = get_edge_src_irn(edge);
311 if (mode_is_datab(get_irn_mode(proj)))
318 /* num in regs: number of ins with mode datab and not ignore */
319 for (i = get_irn_arity(irn) - 1; i >= 0; i--) {
320 ir_node *in = get_irn_n(irn, i);
322 if (!mode_is_datab(get_irn_mode(in)))
325 if (arch_irn_is_ignore(in))
328 if (be_is_live_end(env->liveness, block, in))
334 return num_out - num_in;
338 * descent into a dag and create a pre-order list.
340 static void descent(ir_node *root, ir_node *block, ir_node **list, trace_env_t *env, unsigned path_len)
344 if (! is_Phi(root)) {
345 path_len += exectime(env, root);
346 if (get_irn_critical_path_len(env, root) < path_len) {
347 set_irn_critical_path_len(env, root, path_len);
349 /* calculate number of users (needed for heuristic) */
350 set_irn_num_user(env, root, get_num_successors(root));
352 /* calculate register difference (needed for heuristic) */
353 set_irn_reg_diff(env, root, get_reg_difference(env, root));
355 /* Phi nodes always leave the block */
356 for (i = get_irn_arity(root) - 1; i >= 0; --i) {
357 ir_node *pred = get_irn_n(root, i);
359 DBG((env->dbg, LEVEL_3, " node %+F\n", pred));
361 /* Blocks may happen as predecessors of End nodes */
365 /* already seen nodes are not marked */
366 if (get_irn_link(pred) != MARK)
369 /* don't leave our block */
370 if (get_nodes_block(pred) != block)
373 set_irn_link(pred, NULL);
375 descent(pred, block, list, env, path_len);
378 set_irn_link(root, *list);
383 * Returns non-zero if root is a root in the block block.
385 static int is_root(ir_node *root, ir_node *block)
387 const ir_edge_t *edge;
389 foreach_out_edge(root, edge) {
390 ir_node *succ = get_edge_src_irn(edge);
394 /* Phi nodes are always in "another block */
397 if (get_nodes_block(succ) == block)
404 * Performs initial block calculations for trace scheduling.
406 static void trace_preprocess_block(trace_env_t *env, ir_node *block)
408 ir_node *root = NULL, *preord = NULL;
411 const ir_edge_t *edge;
413 /* First step: Find the root set. */
414 foreach_out_edge(block, edge) {
415 ir_node *succ = get_edge_src_irn(edge);
417 if (is_Block(succ)) {
418 /* A Block-Block edge. This should be the MacroBlock
419 * edge, ignore it. */
420 assert(get_Block_MacroBlock(succ) == block && "Block-Block edge found");
423 if (is_Anchor(succ)) {
424 /* ignore a keep alive edge */
427 if (is_root(succ, block)) {
428 mark_root_node(env, succ);
429 set_irn_link(succ, root);
433 set_irn_link(succ, MARK);
436 /* Second step: calculate the pre-order list. */
438 for (curr = root; curr; curr = irn) {
439 irn = get_irn_link(curr);
440 DBG((env->dbg, LEVEL_2, " DAG root %+F\n", curr));
441 descent(curr, block, &preord, env, 0);
445 /* Third step: calculate the Delay. Note that our
446 * list is now in pre-order, starting at root
448 for (cur_pos = 0, curr = root; curr; curr = get_irn_link(curr), cur_pos++) {
452 /* assure, that branches can be executed last */
456 if (is_root_node(env, curr))
457 d = exectime(env, curr);
460 foreach_out_edge(curr, edge) {
461 ir_node *n = get_edge_src_irn(edge);
463 if (get_nodes_block(n) == block) {
466 ld = latency(env, curr, 1, n, 0) + get_irn_delay(env, n);
472 set_irn_delay(env, curr, d);
473 DB((env->dbg, LEVEL_2, "\t%+F delay %u\n", curr, d));
475 /* set the etime of all nodes to 0 */
476 set_irn_etime(env, curr, 0);
478 set_irn_preorder(env, curr, cur_pos);
483 * This functions gets called after a node finally has been made ready.
485 static void trace_node_ready(void *data, ir_node *irn, ir_node *pred)
487 trace_env_t *env = data;
488 sched_timestep_t etime_p, etime;
490 etime = env->curr_time;
492 etime_p = get_irn_etime(env, pred);
493 etime += latency(env, pred, 1, irn, 0);
494 etime = etime_p > etime ? etime_p : etime;
497 set_irn_etime(env, irn, etime);
498 DB((env->dbg, LEVEL_2, "\tset etime of %+F to %u\n", irn, etime));
502 * Update the current time after irn has been selected.
504 static void trace_update_time(void *data, ir_node *irn)
506 trace_env_t *env = data;
507 if (is_Phi(irn) || get_irn_opcode(irn) == beo_Start) {
508 env->curr_time += get_irn_etime(env, irn);
511 env->curr_time += exectime(env, irn);
516 * Allocates memory and initializes trace scheduling environment.
517 * @param irg The backend irg object
518 * @return The environment
520 static trace_env_t *trace_init(ir_graph *irg)
522 trace_env_t *env = XMALLOCZ(trace_env_t);
523 int nn = get_irg_last_idx(irg);
526 env->sched_info = NEW_ARR_F(trace_irn_t, nn);
527 env->liveness = be_liveness(irg);
528 FIRM_DBG_REGISTER(env->dbg, "firm.be.sched.trace");
530 be_liveness_assure_chk(env->liveness);
531 memset(env->sched_info, 0, nn * sizeof(*(env->sched_info)));
537 * Frees all memory allocated for trace scheduling environment.
538 * @param env The environment
540 static void trace_free(void *data)
542 trace_env_t *env = data;
543 be_liveness_free(env->liveness);
544 DEL_ARR_F(env->sched_info);
549 * Simple selector. Just assure that jumps are scheduled last.
551 static ir_node *basic_selection(ir_nodeset_t *ready_set)
554 ir_nodeset_iterator_t iter;
556 /* assure that branches and constants are executed last */
557 foreach_ir_nodeset(ready_set, irn, iter) {
563 /* at last: schedule branches */
564 irn = get_nodeset_node(ready_set);
570 * The muchnik selector.
572 static ir_node *muchnik_select(void *block_env, ir_nodeset_t *ready_set, ir_nodeset_t *live_set)
574 trace_env_t *env = block_env;
575 ir_nodeset_t mcands, ecands;
576 ir_nodeset_iterator_t iter;
577 sched_timestep_t max_delay = 0;
581 /* calculate the max delay of all candidates */
582 foreach_ir_nodeset(ready_set, irn, iter) {
583 sched_timestep_t d = get_irn_delay(env, irn);
585 max_delay = d > max_delay ? d : max_delay;
588 ir_nodeset_init_size(&mcands, 8);
589 ir_nodeset_init_size(&ecands, 8);
591 /* build mcands and ecands */
592 foreach_ir_nodeset(ready_set, irn, iter) {
593 if (get_irn_delay(env, irn) == max_delay) {
594 ir_nodeset_insert(&mcands, irn);
595 if (get_irn_etime(env, irn) <= env->curr_time)
596 ir_nodeset_insert(&ecands, irn);
601 if (ir_nodeset_size(&mcands) == 1) {
602 irn = get_nodeset_node(&mcands);
603 DB((env->dbg, LEVEL_3, "\tirn = %+F, mcand = 1, max_delay = %u\n", irn, max_delay));
606 int cnt = ir_nodeset_size(&ecands);
608 irn = get_nodeset_node(&ecands);
611 /* BEWARE: don't select a JUMP if others are still possible */
614 DB((env->dbg, LEVEL_3, "\tirn = %+F, ecand = 1, max_delay = %u\n", irn, max_delay));
617 DB((env->dbg, LEVEL_3, "\tecand = %d, max_delay = %u\n", cnt, max_delay));
618 irn = basic_selection(&ecands);
622 DB((env->dbg, LEVEL_3, "\tmcand = %d\n", ir_nodeset_size(&mcands)));
623 irn = basic_selection(&mcands);
630 static void *muchnik_init_graph(const list_sched_selector_t *vtab, ir_graph *irg)
632 trace_env_t *env = trace_init(irg);
633 env->selector = vtab;
634 env->selector_env = (void*) be_get_irg_arch_env(irg);
638 static void *muchnik_init_block(void *graph_env, ir_node *bl)
640 trace_preprocess_block(graph_env, bl);
644 const list_sched_selector_t muchnik_selector = {
648 trace_node_ready, /* node_ready */
649 trace_update_time, /* node_selected */
652 NULL, /* finish_block */
653 trace_free /* finish_graph */
657 * Execute the heuristic function.
659 static ir_node *heuristic_select(void *block_env, ir_nodeset_t *ns, ir_nodeset_t *lv)
661 trace_env_t *trace_env = block_env;
662 ir_node *irn, *cand = NULL;
663 int max_prio = INT_MIN;
664 int cur_prio = INT_MIN;
665 int cur_pressure = ir_nodeset_size(lv);
666 int reg_fact, cand_reg_fact;
667 ir_nodeset_iterator_t iter;
669 /* prefer instructions which can be scheduled early */
671 /* prefer instructions with lots of successors */
672 #define PRIO_NUMSUCCS 8
673 /* prefer instructions with long critical path */
674 #define PRIO_LEVEL 12
675 /* prefer instructions coming early in preorder */
676 #define PRIO_PREORD 8
677 /* weight of current register pressure */
678 #define PRIO_CUR_PRESS 20
679 /* weight of register pressure difference */
680 #define PRIO_CHG_PRESS 8
682 /* priority based selection, heuristic inspired by mueller diss */
683 foreach_ir_nodeset(ns, irn, iter) {
684 /* make sure that branches are scheduled last */
686 int rdiff = get_irn_reg_diff(trace_env, irn);
687 int sign = rdiff < 0;
688 int chg = (rdiff < 0 ? -rdiff : rdiff) << PRIO_CHG_PRESS;
690 /* reg_fact = chg << cur_pressure; */
691 reg_fact = chg * cur_pressure;
693 reg_fact = INT_MAX - 2;
694 reg_fact = sign ? -reg_fact : reg_fact;
696 cur_prio = (get_irn_critical_path_len(trace_env, irn) << PRIO_LEVEL)
697 //- (get_irn_delay(trace_env, irn) << PRIO_LEVEL)
698 + (get_irn_num_user(trace_env, irn) << PRIO_NUMSUCCS)
699 - (get_irn_etime(trace_env, irn) << PRIO_TIME)
700 //- ((get_irn_reg_diff(trace_env, irn) >> PRIO_CHG_PRESS) << ((cur_pressure >> PRIO_CUR_PRESS) - 3))
702 + (get_irn_preorder(trace_env, irn) << PRIO_PREORD); /* high preorder means early schedule */
703 if (cur_prio > max_prio) {
706 cand_reg_fact = reg_fact;
709 DBG((trace_env->dbg, LEVEL_4, "checked NODE %+F\n", irn));
710 DBG((trace_env->dbg, LEVEL_4, "\tpriority: %d\n", cur_prio));
711 DBG((trace_env->dbg, LEVEL_4, "\tpath len: %d (%d)\n", get_irn_critical_path_len(trace_env, irn), get_irn_critical_path_len(trace_env, irn) << PRIO_LEVEL));
712 DBG((trace_env->dbg, LEVEL_4, "\tdelay: %d (%d)\n", get_irn_delay(trace_env, irn), get_irn_delay(trace_env, irn) << PRIO_LEVEL));
713 DBG((trace_env->dbg, LEVEL_4, "\t#user: %d (%d)\n", get_irn_num_user(trace_env, irn), get_irn_num_user(trace_env, irn) << PRIO_NUMSUCCS));
714 DBG((trace_env->dbg, LEVEL_4, "\tetime: %d (%d)\n", get_irn_etime(trace_env, irn), 0 - (get_irn_etime(trace_env, irn) << PRIO_TIME)));
715 DBG((trace_env->dbg, LEVEL_4, "\tpreorder: %d (%d)\n", get_irn_preorder(trace_env, irn), get_irn_preorder(trace_env, irn) << PRIO_PREORD));
716 DBG((trace_env->dbg, LEVEL_4, "\treg diff: %d (%d)\n", get_irn_reg_diff(trace_env, irn), 0 - reg_fact));
717 DBG((trace_env->dbg, LEVEL_4, "\tpressure: %d\n", cur_pressure));
722 DBG((trace_env->dbg, LEVEL_4, "heuristic selected %+F:\n", cand));
725 cand = basic_selection(ns);
731 const list_sched_selector_t heuristic_selector = {
735 trace_node_ready, /* node_ready */
736 trace_update_time, /* node_selected */
739 NULL, /* finish_block */
740 trace_free /* finish_graph */