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 Spillslot coalescer.
23 * @author Matthias Braun
37 #include "unionfind.h"
43 #include "bespillslots.h"
44 #include "bechordal_t.h"
45 #include "bestatevent.h"
47 #include "beintlive_t.h"
51 #define DBG_COALESCING 1
52 #define DBG_INTERFERENCES 2
54 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
56 typedef struct spill_t {
58 const ir_mode *mode; /**< mode of the spilled value */
59 int alignment; /**< alignment for the spilled value */
60 int spillslot; /**< index into spillslot_unionfind structure */
63 typedef struct affinity_edge_t {
74 affinity_edge_t **affinity_edges;
76 set_frame_entity_func set_frame_entity;
77 bool at_begin; /**< frame entities should be allocate at
78 the beginning of the stackframe */
81 /** Compare 2 affinity edges (used in quicksort) */
82 static int cmp_affinity(const void *d1, const void *d2)
84 const affinity_edge_t * const *e1 = (const affinity_edge_t**)d1;
85 const affinity_edge_t * const *e2 = (const affinity_edge_t**)d2;
87 /* sort in descending order */
88 return (*e1)->affinity < (*e2)->affinity ? 1 : -1;
91 static int cmp_spill(const void* d1, const void* d2, size_t size)
93 const spill_t* s1 = (const spill_t*)d1;
94 const spill_t* s2 = (const spill_t*)d2;
97 return s1->spill != s2->spill;
100 static spill_t *get_spill(be_fec_env_t *env, ir_node *node)
103 int hash = hash_irn(node);
106 res = (spill_t*)set_find(env->spills, &spill, sizeof(spill), hash);
112 static inline ir_node *get_memory_edge(const ir_node *node)
116 arity = get_irn_arity(node);
117 for (i = arity - 1; i >= 0; --i) {
118 ir_node *arg = get_irn_n(node, i);
119 if (get_irn_mode(arg) == mode_M)
126 static spill_t *collect_spill(be_fec_env_t *env, ir_node *node,
127 const ir_mode *mode, int align)
130 int hash = hash_irn(node);
132 /* insert into set of spills if not already there */
134 res = (spill_t*)set_find(env->spills, &spill, sizeof(spill), hash);
137 spill.spillslot = set_count(env->spills);
139 spill.alignment = align;
140 res = (spill_t*)set_insert(env->spills, &spill, sizeof(spill), hash);
141 DB((dbg, DBG_COALESCING, "Slot %d: %+F\n", spill.spillslot, node));
143 assert(res->mode == mode);
144 assert(res->alignment == align);
150 static spill_t *collect_memphi(be_fec_env_t *env, ir_node *node,
151 const ir_mode *mode, int align)
155 int hash = hash_irn(node);
156 const ir_exec_freq *exec_freq = be_get_irg_exec_freq(env->irg);
158 assert(is_Phi(node));
161 res = (spill_t*)set_find(env->spills, &spill, sizeof(spill), hash);
163 assert(res->mode == mode);
164 assert(res->alignment == align);
168 spill.spillslot = set_count(env->spills);
170 spill.alignment = align;
171 DB((dbg, DBG_COALESCING, "Slot %d: %+F\n", spill.spillslot, node));
172 res = (spill_t*)set_insert(env->spills, &spill, sizeof(spill), hash);
174 /* collect attached spills and mem-phis */
175 arity = get_irn_arity(node);
176 for (i = 0; i < arity; ++i) {
177 affinity_edge_t *affinty_edge;
178 ir_node *arg = get_irn_n(node, i);
182 arg_spill = collect_memphi(env, arg, mode, align);
184 arg_spill = collect_spill(env, arg, mode, align);
187 /* add an affinity edge */
188 affinty_edge = OALLOC(&env->obst, affinity_edge_t);
189 affinty_edge->affinity = get_block_execfreq(exec_freq, get_nodes_block(arg));
190 affinty_edge->slot1 = res->spillslot;
191 affinty_edge->slot2 = arg_spill->spillslot;
192 ARR_APP1(affinity_edge_t*, env->affinity_edges, affinty_edge);
198 void be_node_needs_frame_entity(be_fec_env_t *env, ir_node *node,
199 const ir_mode *mode, int align)
201 ir_node *spillnode = get_memory_edge(node);
204 assert(spillnode != NULL);
206 /* walk upwards and collect all phis and spills on this way */
207 if (is_Phi(spillnode)) {
208 spill = collect_memphi(env, spillnode, mode, align);
210 spill = collect_spill(env, spillnode, mode, align);
213 ARR_APP1(ir_node *, env->reloads, node);
218 static int merge_interferences(be_fec_env_t *env, bitset_t** interferences,
219 int* spillslot_unionfind, int s1, int s2)
225 /* merge spillslots and interferences */
226 res = uf_union(spillslot_unionfind, s1, s2);
227 /* we assume that we always merge s2 to s1 so swap s1, s2 if necessary */
234 bitset_or(interferences[s1], interferences[s2]);
236 /* update other interferences */
237 spillcount = set_count(env->spills);
238 for (i = 0; i < spillcount; ++i) {
239 bitset_t *intfs = interferences[i];
240 if (bitset_is_set(intfs, s2))
241 bitset_set(intfs, s1);
247 static int my_values_interfere2(ir_graph *irg, const ir_node *a,
250 be_lv_t *lv = be_get_irg_liveness(irg);
252 int a2b = _value_dominates(a, b);
253 int b2a = _value_dominates(b, a);
255 /* If there is no dominance relation, they do not interfere. */
256 if ((a2b | b2a) > 0) {
257 const ir_edge_t *edge;
261 * Adjust a and b so, that a dominates b if
262 * a dominates b or vice versa.
265 const ir_node *t = a;
270 bb = get_nodes_block(b);
273 * If a is live end in b's block it is
274 * live at b's definition (a dominates b)
276 if (be_is_live_end(lv, bb, a))
280 * Look at all usages of a.
281 * If there's one usage of a in the block of b, then
282 * we check, if this use is dominated by b, if that's true
283 * a and b interfere. Note that b must strictly dominate the user,
284 * since if b is the last user of in the block, b and a do not
286 * Uses of a not in b's block can be disobeyed, because the
287 * check for a being live at the end of b's block is already
290 foreach_out_edge(a, edge) {
291 const ir_node *user = get_edge_src_irn(edge);
293 const ir_edge_t *edge2;
294 foreach_out_edge(user, edge2) {
295 const ir_node *user2 = get_edge_src_irn(edge2);
296 assert(!is_Sync(user2));
297 if (get_nodes_block(user2) == bb && !is_Phi(user2) &&
298 _value_strictly_dominates(b, user2))
302 if (get_nodes_block(user) == bb && !is_Phi(user) &&
303 _value_strictly_dominates(b, user))
313 * same as values_interfere but with special handling for Syncs
315 static int my_values_interfere(ir_graph *irg, ir_node *a, ir_node *b)
318 int i, arity = get_irn_arity(a);
319 for (i = 0; i < arity; ++i) {
320 ir_node *in = get_irn_n(a, i);
321 if (my_values_interfere(irg, in, b))
325 } else if (is_Sync(b)) {
326 int i, arity = get_irn_arity(b);
327 for (i = 0; i < arity; ++i) {
328 ir_node *in = get_irn_n(b, i);
329 /* a is not a sync, so no need for my_values_interfere */
330 if (my_values_interfere2(irg, a, in))
336 return my_values_interfere2(irg, a, b);
340 * A greedy coalescing algorithm for spillslots:
341 * 1. Sort the list of affinity edges
342 * 2. Try to merge slots with affinity edges (most expensive slots first)
343 * 3. Try to merge everything else that is possible
345 static void do_greedy_coalescing(be_fec_env_t *env)
351 int affinity_edge_count;
352 bitset_t **interferences;
353 int* spillslot_unionfind;
356 spillcount = set_count(env->spills);
362 DB((dbg, DBG_COALESCING, "Coalescing %d spillslots\n", spillcount));
364 interferences = OALLOCN(&data, bitset_t*, spillcount);
365 spillslot_unionfind = OALLOCN(&data, int, spillcount);
366 spilllist = OALLOCN(&data, spill_t*, spillcount);
368 uf_init(spillslot_unionfind, spillcount);
371 memset(spilllist, 0, spillcount * sizeof(spilllist[0]));
375 foreach_set(env->spills, spill_t*, spill) {
376 assert(spill->spillslot < spillcount);
377 spilllist[spill->spillslot] = spill;
381 for (i = 0; i < spillcount; ++i) {
382 interferences[i] = bitset_obstack_alloc(&data, spillcount);
385 /* construct interferences */
386 for (i = 0; i < spillcount; ++i) {
387 ir_node *spill1 = spilllist[i]->spill;
389 if (is_NoMem(spill1))
392 for (i2 = i+1; i2 < spillcount; ++i2) {
393 ir_node *spill2 = spilllist[i2]->spill;
395 if (is_NoMem(spill2))
398 if (my_values_interfere(env->irg, spill1, spill2)) {
399 DB((dbg, DBG_INTERFERENCES,
400 "Slot %d and %d interfere\n", i, i2));
402 bitset_set(interferences[i], i2);
403 bitset_set(interferences[i2], i);
408 /* sort affinity edges */
409 affinity_edge_count = ARR_LEN(env->affinity_edges);
410 qsort(env->affinity_edges, affinity_edge_count,
411 sizeof(env->affinity_edges[0]), cmp_affinity);
413 /*dump_interference_graph(env, interferences, "before"); */
415 /* try to merge affine nodes */
416 for (i = 0; i < affinity_edge_count; ++i) {
417 const affinity_edge_t *edge = env->affinity_edges[i];
418 int s1 = uf_find(spillslot_unionfind, edge->slot1);
419 int s2 = uf_find(spillslot_unionfind, edge->slot2);
421 /* test if values interfere */
422 if (bitset_is_set(interferences[s1], s2)) {
423 assert(bitset_is_set(interferences[s2], s1));
427 DB((dbg, DBG_COALESCING,
428 "Merging %d and %d because of affinity edge\n", s1, s2));
430 merge_interferences(env, interferences, spillslot_unionfind, s1, s2);
433 /* try to merge as much remaining spillslots as possible */
434 for (i = 0; i < spillcount; ++i) {
435 int s1 = uf_find(spillslot_unionfind, i);
439 for (i2 = i+1; i2 < spillcount; ++i2) {
440 int s2 = uf_find(spillslot_unionfind, i2);
444 /* test if values interfere
445 * we have to test n1-n2 and n2-n1, because only 1 side gets updated
446 * when node merging occurs
448 if (bitset_is_set(interferences[s1], s2)) {
449 assert(bitset_is_set(interferences[s2], s1));
453 DB((dbg, DBG_COALESCING,
454 "Merging %d and %d because it is possible\n", s1, s2));
456 if (merge_interferences(env, interferences, spillslot_unionfind, s1, s2) != 0) {
457 /* we can break the loop here, because s2 is the new supernode
458 * now and we'll test s2 again later anyway */
464 /* assign spillslots to spills */
465 for (i = 0; i < spillcount; ++i) {
466 spill_t *spill = spilllist[i];
468 spill->spillslot = uf_find(spillslot_unionfind, i);
471 /*dump_interference_graph(env, interferences, "after");*/
472 obstack_free(&data, 0);
477 typedef struct spill_slot_t {
483 typedef struct memperm_entry_t {
488 struct memperm_entry_t *next;
491 typedef struct memperm_t {
494 memperm_entry_t *entries;
497 static int cmp_memperm(const void* d1, const void* d2, size_t size)
499 const memperm_t* e1 = (const memperm_t*)d1;
500 const memperm_t* e2 = (const memperm_t*)d2;
503 return e1->block != e2->block;
506 static memperm_t *get_memperm(be_fec_env_t *env, ir_node *block)
508 memperm_t entry, *res;
512 hash = hash_irn(block);
514 res = (memperm_t*)set_find(env->memperms, &entry, sizeof(entry), hash);
517 entry.entrycount = 0;
518 entry.entries = NULL;
519 res = (memperm_t*)set_insert(env->memperms, &entry, sizeof(entry), hash);
525 static ir_entity* create_stack_entity(be_fec_env_t *env, spill_slot_t *slot)
527 ir_graph *irg = env->irg;
528 ir_type *frame = get_irg_frame_type(irg);
529 ir_entity *res = frame_alloc_area(frame, slot->size, slot->align,
532 /* adjust size of the entity type... */
533 ir_type *enttype = get_entity_type(res);
534 set_type_size_bytes(enttype, slot->size);
542 * Enlarges a spillslot (if necessary) so that it can carry a value of size
543 * @p othersize and alignment @p otheralign.
545 static void enlarge_spillslot(spill_slot_t *slot, int otheralign, int othersize)
547 if (othersize > slot->size) {
548 slot->size = othersize;
550 if (otheralign > slot->align) {
551 if (otheralign % slot->align != 0)
552 slot->align *= otheralign;
554 slot->align = otheralign;
555 } else if (slot->align % otheralign != 0) {
556 slot->align *= otheralign;
560 static void assign_spill_entity(be_fec_env_t *env,
561 ir_node *node, ir_entity *entity)
568 arity = get_irn_arity(node);
569 for (i = 0; i < arity; ++i) {
570 ir_node *in = get_irn_n(node, i);
573 assign_spill_entity(env, in, entity);
578 /* beware: we might have Stores with Memory Proj's, ia32 fisttp for
580 node = skip_Proj(node);
581 assert(arch_get_frame_entity(node) == NULL);
582 env->set_frame_entity(node, entity);
586 * Create stack entities for the spillslots and assign them to the spill and
589 static void assign_spillslots(be_fec_env_t *env)
591 int spillcount = set_count(env->spills);
592 spill_slot_t *spillslots = ALLOCANZ(spill_slot_t, spillcount);
596 /* construct spillslots */
597 foreach_set(env->spills, spill_t*, spill) {
598 int slotid = spill->spillslot;
599 const ir_mode *mode = spill->mode;
600 spill_slot_t *slot = & (spillslots[slotid]);
601 int size = get_mode_size_bytes(mode);
602 int align = spill->alignment;
604 if (slot->align == 0 && slot->size == 0) {
608 enlarge_spillslot(slot, align, size);
612 foreach_set(env->spills, spill_t*, spill) {
613 ir_node *node = spill->spill;
614 int slotid = spill->spillslot;
617 slot = &spillslots[slotid];
618 if (slot->entity == NULL) {
619 create_stack_entity(env, slot);
624 ir_node *block = get_nodes_block(node);
626 /* should be a PhiM */
627 assert(is_Phi(node));
629 for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
630 ir_node *arg = get_irn_n(node, i);
631 ir_node *predblock = get_Block_cfgpred_block(block, i);
635 argspill = get_spill(env, arg);
636 assert(argspill != NULL);
638 argslotid = argspill->spillslot;
639 if (slotid != argslotid) {
641 memperm_entry_t *entry;
642 spill_slot_t *argslot = &spillslots[argslotid];
643 if (argslot->entity == NULL) {
644 create_stack_entity(env, argslot);
647 memperm = get_memperm(env, predblock);
649 entry = OALLOC(&env->obst, memperm_entry_t);
652 entry->in = argslot->entity;
653 entry->out = slot->entity;
654 entry->next = memperm->entries;
655 memperm->entrycount++;
656 memperm->entries = entry;
660 assign_spill_entity(env, node, slot->entity);
664 for (i = 0; i < ARR_LEN(env->reloads); ++i) {
665 ir_node *reload = env->reloads[i];
666 ir_node *spillnode = get_memory_edge(reload);
667 spill_t *spill = get_spill(env, spillnode);
668 const spill_slot_t *slot = & spillslots[spill->spillslot];
670 assert(slot->entity != NULL);
672 env->set_frame_entity(reload, slot->entity);
677 * Returns the last node in a block which is no control flow changing node
679 static ir_node *get_end_of_block_insertion_point(ir_node* block)
681 ir_node* ins = sched_last(block);
682 while (is_Proj(ins) && get_irn_mode(ins) == mode_X) {
683 ins = sched_prev(ins);
689 ir_node *prev = sched_prev(ins);
699 static void create_memperms(be_fec_env_t *env)
703 foreach_set(env->memperms, memperm_t*, memperm) {
704 ir_node **nodes = ALLOCAN(ir_node*, memperm->entrycount);
705 memperm_entry_t *entry;
707 ir_node *mempermnode;
710 assert(memperm->entrycount > 0);
712 for (entry = memperm->entries, i = 0; entry != NULL; entry = entry->next, ++i) {
713 ir_node* arg = get_irn_n(entry->node, entry->pos);
717 mempermnode = be_new_MemPerm(memperm->block, memperm->entrycount,
720 /* insert node into schedule */
721 blockend = get_end_of_block_insertion_point(memperm->block);
722 sched_add_before(blockend, mempermnode);
723 stat_ev_dbl("mem_perm", memperm->entrycount);
726 for (entry = memperm->entries; entry != NULL; entry = entry->next, ++i) {
728 ir_node* arg = get_irn_n(entry->node, entry->pos);
730 be_set_MemPerm_in_entity(mempermnode, i, entry->in);
731 be_set_MemPerm_out_entity(mempermnode, i, entry->out);
732 proj = new_r_Proj(mempermnode, get_irn_mode(arg), i);
734 set_irn_n(entry->node, entry->pos, proj);
739 static int count_spillslots(const be_fec_env_t *env)
741 const spill_t *spill;
742 int spillcount = set_count(env->spills);
743 bitset_t *counted = bitset_alloca(spillcount);
747 foreach_set(env->spills, spill_t*, spill) {
748 int spillslot = spill->spillslot;
749 if (!bitset_is_set(counted, spillslot)) {
751 bitset_set(counted, spillslot);
758 be_fec_env_t *be_new_frame_entity_coalescer(ir_graph *irg)
760 be_fec_env_t *env = XMALLOCZ(be_fec_env_t);
762 be_liveness_assure_chk(be_assure_liveness(irg));
764 obstack_init(&env->obst);
766 env->spills = new_set(cmp_spill, 10);
767 env->reloads = NEW_ARR_F(ir_node*, 0);
768 env->affinity_edges = NEW_ARR_F(affinity_edge_t*, 0);
769 env->memperms = new_set(cmp_memperm, 10);
774 void be_free_frame_entity_coalescer(be_fec_env_t *env)
776 del_set(env->memperms);
777 DEL_ARR_F(env->reloads);
778 DEL_ARR_F(env->affinity_edges);
779 del_set(env->spills);
780 obstack_free(&env->obst, NULL);
785 void be_assign_entities(be_fec_env_t *env,
786 set_frame_entity_func set_frame_entity,
787 bool alloc_entities_at_begin)
789 env->set_frame_entity = set_frame_entity;
790 env->at_begin = alloc_entities_at_begin;
792 stat_ev_dbl("spillslots", set_count(env->spills));
794 if (be_coalesce_spill_slots) {
795 do_greedy_coalescing(env);
798 stat_ev_dbl("spillslots_after_coalescing", count_spillslots(env));
800 assign_spillslots(env);
802 create_memperms(env);
805 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spillslots);
806 void be_init_spillslots(void)
808 FIRM_DBG_REGISTER(dbg, "firm.be.spillslots");