2 * Author: Daniel Grund, Sebastian Hack
4 * Copyright: (c) Universitaet Karlsruhe
5 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
16 #include "iredges_t.h"
26 #include "besched_t.h"
29 #include "bechordal_t.h"
32 /* This enables re-computation of values. Current state: Unfinished and buggy. */
35 typedef struct _reloader_t reloader_t;
36 typedef struct _spill_info_t spill_info_t;
43 struct _spill_info_t {
44 ir_node *spilled_node;
45 reloader_t *reloaders;
48 typedef struct _spill_ctx_t {
49 ir_node *spilled; /**< The spilled node. */
50 ir_node *user; /**< The node this spill is for. */
51 ir_node *spill; /**< The spill itself. */
55 const arch_register_class_t *cls;
56 const be_chordal_env_t *chordal_env;
59 set *spills; /**< all spill_info_t's, which must be placed */
60 pset *mem_phis; /**< set of all special spilled phis. allocated and freed separately */
61 decide_irn_t is_mem_phi; /**< callback func to decide if a phi needs special spilling */
62 void *data; /**< data passed to all callbacks */
63 DEBUG_ONLY(firm_dbg_module_t *dbg;)
66 /* associated Phi -> Spill*/
67 typedef struct _phi_spill_assoc_t {
73 * Compare two Phi->Spill associations.
75 static int cmp_phi_spill_assoc(const void *a, const void *b, size_t n) {
76 const phi_spill_assoc_t *p1 = a;
77 const phi_spill_assoc_t *p2 = b;
78 return p1->phi != p2->phi;
82 * compare two spill contexts.
84 static int cmp_spillctx(const void *a, const void *b, size_t n) {
85 const spill_ctx_t *p = a;
86 const spill_ctx_t *q = b;
87 return p->user != q->user || p->spilled != q->spilled;
91 * Compare two spill infos.
93 static int cmp_spillinfo(const void *x, const void *y, size_t size) {
94 const spill_info_t *xx = x;
95 const spill_info_t *yy = y;
96 return xx->spilled_node != yy->spilled_node;
100 /* Sets the debug module of a spill environment. */
101 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
106 /* Creates a new spill environment. */
107 spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env, decide_irn_t is_mem_phi, void *data) {
108 spill_env_t *env = xmalloc(sizeof(env[0]));
109 env->spill_ctxs = new_set(cmp_spillctx, 1024);
110 env->spills = new_set(cmp_spillinfo, 1024);
111 env->cls = chordal_env->cls;
112 env->is_mem_phi = is_mem_phi;
114 env->chordal_env = chordal_env;
115 obstack_init(&env->obst);
119 /* Deletes a spill environment. */
120 void be_delete_spill_env(spill_env_t *senv) {
121 del_set(senv->spill_ctxs);
122 del_set(senv->spills);
123 obstack_free(&senv->obst, NULL);
128 * Returns a spill context. If the context did not exists, create one.
130 * @param sc the set containing all spill contexts
131 * @param to_spill the node that should be spilled
132 * @param ctx_irn an user of the spilled node
134 * @return a spill context.
136 static spill_ctx_t *be_get_spill_ctx(set *sc, ir_node *to_spill, ir_node *ctx_irn) {
139 templ.spilled = to_spill;
140 templ.user = ctx_irn;
143 return set_insert(sc, &templ, sizeof(templ), HASH_COMBINE(HASH_PTR(to_spill), HASH_PTR(ctx_irn)));
149 * @param senv the spill environment
150 * @param irn the node that should be spilled
151 * @param ctx_irn an user of the spilled node
153 * @return a be_Spill node
155 static ir_node *be_spill_irn(spill_env_t *senv, ir_node *irn, ir_node *ctx_irn) {
157 DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", irn, ctx_irn));
159 ctx = be_get_spill_ctx(senv->spill_ctxs, irn, ctx_irn);
161 const be_main_env_t *env = senv->chordal_env->birg->main_env;
162 ctx->spill = be_spill(env->arch_env, irn, ctx_irn);
169 * If the first usage of a Phi result would be out of memory
170 * there is no sense in allocating a register for it.
171 * Thus we spill it and all its operands to the same spill slot.
172 * Therefore the phi/dataB becomes a phi/Memory
174 * @param senv the spill environment
175 * @param phi the Phi node that should be spilled
176 * @param ctx_irn an user of the spilled node
178 * @return a be_Spill node
180 static ir_node *be_spill_phi(spill_env_t *senv, ir_node *phi, ir_node *ctx_irn, unsigned visited_nr, set *already_visited_phis) {
181 int i, n = get_irn_arity(phi);
182 ir_graph *irg = senv->chordal_env->irg;
183 ir_node *bl = get_nodes_block(phi);
184 ir_node **ins, *phi_spill;
185 phi_spill_assoc_t key;
189 DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", phi, ctx_irn));
191 /* build a new PhiM */
192 NEW_ARR_A(ir_node *, ins, n);
193 for (i = 0; i < n; ++i) {
194 ins[i] = new_r_Bad(irg);
196 phi_spill = new_r_Phi(senv->chordal_env->irg, bl, n, ins, mode_M);
198 key.spill = phi_spill;
199 set_insert(already_visited_phis, &key, sizeof(key), HASH_PTR(phi));
201 /* search an existing spill for this context */
202 ctx = be_get_spill_ctx(senv->spill_ctxs, phi, ctx_irn);
204 /* if not found spill the phi */
206 set_irn_visited(phi, visited_nr);
208 /* collect all arguments of the phi */
209 for (i = 0; i < n; ++i) {
210 ir_node *arg = get_irn_n(phi, i);
212 phi_spill_assoc_t *entry;
214 if(is_Phi(arg) && pset_find_ptr(senv->mem_phis, arg)) {
215 if (get_irn_visited(arg) < visited_nr)
216 sub_res = be_spill_phi(senv, arg, ctx_irn, visited_nr, already_visited_phis);
218 /* we already visited the argument phi: get it's spill */
221 entry = set_find(already_visited_phis, &key, sizeof(key), HASH_PTR(arg));
222 assert(entry && "argument phi already visited, but no spill found?!?");
223 sub_res = entry->spill;
224 assert(sub_res && "spill missing?!?");
228 sub_res = be_spill_irn(senv, arg, ctx_irn);
230 set_irn_n(phi_spill, i, sub_res);
233 ctx->spill = phi_spill;
241 * @param senv the spill environment
242 * @param irn the node that should be spilled
243 * @param ctx_irn an user of the spilled node
245 * @return a be_Spill node
247 static ir_node *be_spill_node(spill_env_t *senv, ir_node *to_spill, unsigned visited_nr) {
248 ir_graph *irg = get_irn_irg(to_spill);
249 int save_optimize = get_optimize();
250 int save_normalize = get_opt_normalize();
251 set *already_visited_phis = new_set(cmp_phi_spill_assoc, 10);
255 * Disable optimization so that the phi functions do not
259 set_opt_normalize(0);
261 if (pset_find_ptr(senv->mem_phis, to_spill))
262 res = be_spill_phi(senv, to_spill, to_spill, visited_nr, already_visited_phis);
264 res = be_spill_irn(senv, to_spill, to_spill);
266 del_set(already_visited_phis);
268 /* reset the optimizations */
269 set_optimize(save_optimize);
270 set_opt_normalize(save_normalize);
280 * Check if a spilled node could be rematerialized.
282 * @param senv the spill environment
283 * @param spill the Spill node
284 * @param spilled the node that was spilled
285 * @param reloader a irn that requires a reload
287 static int check_remat_conditions(spill_env_t *senv, ir_node *spill, ir_node *spilled, ir_node *reloader) {
290 /* check for 'normal' spill and general remat condition */
291 if (!be_is_Spill(spill) || !arch_irn_is(senv->chordal_env->birg->main_env->arch_env, spilled, rematerializable))
294 /* check availability of original arguments */
295 if (is_Block(reloader)) {
297 /* we want to remat at the end of a block.
298 * thus all arguments must be alive at the end of the block
300 for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
301 ir_node *arg = get_irn_n(spilled, pos);
302 if (!is_live_end(reloader, arg))
308 /* we want to remat before the insn reloader
309 * thus an arguments is alive if
310 * - it interferes with the reloaders result
312 * - or it is (last-) used by reloader itself
314 for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
315 ir_node *arg = get_irn_n(spilled, pos);
318 if (values_interfere(reloader, arg))
321 for (i=0, m=get_irn_arity(reloader); i<m; ++i) {
322 ir_node *rel_arg = get_irn_n(reloader, i);
327 /* arg is not alive before reloader */
339 #else /* BUGGY_REMAT */
342 * A very simple rematerialization checker.
344 * @param senv the spill environment
345 * @param spill the Spill node
346 * @param spilled the node that was spilled
347 * @param reloader a irn that requires a reload
349 static int check_remat_conditions(spill_env_t *senv, ir_node *spill, ir_node *spilled, ir_node *reloader) {
350 const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
352 return get_irn_arity(spilled) == 0 &&
353 be_is_Spill(spill) &&
354 arch_irn_is(aenv, spilled, rematerializable);
357 #endif /* BUGGY_REMAT */
362 * Re-materialize a node.
364 * @param senv the spill environment
365 * @param spilled the node that was spilled
366 * @param reloader a irn that requires a reload
368 static ir_node *do_remat(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
370 ir_node *bl = (is_Block(reloader)) ? reloader : get_nodes_block(reloader);
372 /* recompute the value */
373 res = new_ir_node(get_irn_dbg_info(spilled), senv->chordal_env->irg, bl,
375 get_irn_mode(spilled),
376 get_irn_arity(spilled),
377 get_irn_in(spilled) + 1);
378 copy_node_attr(spilled, res);
380 DBG((senv->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
382 /* insert in schedule */
383 if (is_Block(reloader)) {
384 ir_node *insert = sched_skip(reloader, 0, sched_skip_cf_predicator, (void *) senv->chordal_env->birg->main_env->arch_env);
385 sched_add_after(insert, res);
387 sched_add_before(reloader, res);
394 * Walker: fills the mem_phis set by evaluating Phi nodes
395 * using the is_mem_phi() callback.
397 static void phi_walker(ir_node *irn, void *env) {
398 spill_env_t *senv = env;
401 const arch_env_t *arch = senv->chordal_env->birg->main_env->arch_env;
402 if (arch_irn_has_reg_class(arch, irn, 0, senv->cls) &&
403 senv->is_mem_phi(irn, senv->data)) {
404 DBG((senv->dbg, LEVEL_1, " %+F\n", irn));
405 pset_insert_ptr(senv->mem_phis, irn);
410 void be_insert_spills_reloads(spill_env_t *senv, pset *reload_set) {
411 const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
412 ir_graph *irg = senv->chordal_env->irg;
418 /* get all special spilled phis */
419 DBG((senv->dbg, LEVEL_1, "Mem-phis:\n"));
420 senv->mem_phis = pset_new_ptr_default();
421 irg_walk_graph(senv->chordal_env->irg, phi_walker, NULL, senv);
423 /* Add reloads for mem_phis */
424 /* BETTER: These reloads (1) should only be inserted, if they are really needed */
425 DBG((senv->dbg, LEVEL_1, "Reloads for mem-phis:\n"));
426 for(irn = pset_first(senv->mem_phis); irn; irn = pset_next(senv->mem_phis)) {
428 DBG((senv->dbg, LEVEL_1, " Mem-phi %+F\n", irn));
429 foreach_out_edge(irn, e) {
430 ir_node *user = e->src;
431 if (is_Phi(user) && !pset_find_ptr(senv->mem_phis, user)) {
432 ir_node *use_bl = get_nodes_block(user);
433 DBG((senv->dbg, LEVEL_1, " non-mem-phi user %+F\n", user));
434 be_add_reload_on_edge(senv, irn, use_bl, e->pos); /* (1) */
439 visited_nr = get_irg_visited(irg) + 1;
440 set_irg_visited(irg, visited_nr);
442 /* process each spilled node */
443 DBG((senv->dbg, LEVEL_1, "Insert spills and reloads:\n"));
444 possibly_dead = new_pdeq();
445 for(si = set_first(senv->spills); si; si = set_next(senv->spills)) {
447 ir_mode *mode = get_irn_mode(si->spilled_node);
448 pset *values = pset_new_ptr(16);
450 /* go through all reloads for this spill */
451 for(rld = si->reloaders; rld; rld = rld->next) {
454 /* the spill for this reloader */
455 ir_node *spill = be_spill_node(senv, si->spilled_node, visited_nr);
458 if (check_remat_conditions(senv, spill, si->spilled_node, rld->reloader)) {
459 new_val = do_remat(senv, si->spilled_node, rld->reloader);
460 pdeq_putl(possibly_dead, spill);
465 new_val = be_reload(aenv, senv->cls, rld->reloader, mode, spill);
467 DBG((senv->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
468 pset_insert_ptr(values, new_val);
470 pset_insert_ptr(reload_set, new_val);
473 /* introduce copies, rewire the uses */
474 assert(pset_count(values) > 0 && "???");
475 pset_insert_ptr(values, si->spilled_node);
476 be_ssa_constr_set_ignore(senv->chordal_env->dom_front, values, senv->mem_phis);
481 foreach_pset(senv->mem_phis, irn) {
483 for (i = 0, n = get_irn_arity(irn); i < n; ++i) {
484 pdeq_putl(possibly_dead, get_irn_n(irn, i));
485 set_irn_n(irn, i, new_r_Bad(senv->chordal_env->irg));
490 /* check if possibly dead nodes are really dead yet */
491 while (! pdeq_empty(possibly_dead)) {
492 ir_node *irn = pdeq_getr(possibly_dead);
493 const ir_edge_t *edge = get_irn_out_edge_first(irn);
497 for (i = get_irn_arity(irn) - 1; i >= 0; --i) {
498 pdeq_putl(possibly_dead, get_irn_n(irn, i));
499 set_irn_n(irn, i, new_r_Bad(senv->chordal_env->irg));
504 del_pdeq(possibly_dead);
505 del_pset(senv->mem_phis);
508 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before) {
509 spill_info_t templ, *res;
512 templ.spilled_node = to_spill;
513 templ.reloaders = NULL;
514 res = set_insert(senv->spills, &templ, sizeof(templ), HASH_PTR(to_spill));
516 rel = obstack_alloc(&senv->obst, sizeof(rel[0]));
517 rel->reloader = before;
518 rel->next = res->reloaders;
519 res->reloaders = rel;
522 void be_add_reload_on_edge(spill_env_t *senv, ir_node *to_spill, ir_node *bl, int pos) {
523 ir_node *insert_bl = get_irn_arity(bl) == 1 ? sched_first(bl) : get_Block_cfgpred_block(bl, pos);
524 be_add_reload(senv, to_spill, insert_bl);
529 /****************************************
531 SPILL SLOT MANAGEMENT AND OPTS
533 ****************************************/
535 typedef struct _spill_slot_t {
539 ir_mode *largest_mode; /* the mode of all members with largest size */
542 typedef struct _ss_env_t {
544 be_chordal_env_t *cenv;
545 pmap *slots; /* maps spill_contexts to spill_slots */
546 pmap *types; /* maps modes to types */
547 DEBUG_ONLY(firm_dbg_module_t *dbg;)
552 * Walker: compute the spill slots
554 static void compute_spill_slots_walker(ir_node *spill, void *env) {
555 ss_env_t *ssenv = env;
560 if (!be_is_Spill(spill))
563 /* check, if this spill is for a context already known */
564 ctx = be_get_Spill_context(spill);
565 entry = pmap_find(ssenv->slots, ctx);
568 struct _arch_env_t *arch_env = ssenv->cenv->birg->main_env->arch_env;
569 const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
570 ir_mode *largest_mode = arch_register_class_mode(cls);
572 /* this is a new spill context */
573 ss = obstack_alloc(&ssenv->ob, sizeof(*ss));
574 ss->members = pset_new_ptr(8);
575 ss->largest_mode = largest_mode;
576 ss->size = get_mode_size_bytes(ss->largest_mode);
577 ss->align = arch_isa_get_reg_class_alignment(arch_env->isa, cls);
578 pmap_insert(ssenv->slots, ctx, ss);
580 /* values with the same spill_ctx must go into the same spill slot */
584 /* ugly mega assert :-) */
587 struct _arch_env_t *arch_env = ssenv->cenv->birg->main_env->arch_env;
588 const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
589 int size = get_mode_size_bytes(arch_register_class_mode(cls));
590 assert(ss->size == size && "Different sizes for the same spill slot are not allowed.");
591 for (irn = pset_first(ss->members); irn; irn = pset_next(ss->members)) {
592 /* use values_interfere here, because it uses the dominance check,
593 which does work for values in memory */
594 assert(!values_interfere(spill, irn) && "Spills for the same spill slot must not interfere!");
600 pset_insert_ptr(ss->members, spill);
604 * qsort compare function, sort spill slots by size.
606 static int ss_sorter(const void *v1, const void *v2) {
607 const spill_slot_t **ss1 = (const spill_slot_t **)v1;
608 const spill_slot_t **ss2 = (const spill_slot_t **)v2;
609 return ((int) (*ss2)->size) - ((int) (*ss1)->size);
614 * This function should optimize the spill slots.
615 * - Coalescing of multiple slots
616 * - Ordering the slots
618 * Input slots are in @p ssenv->slots
619 * @p size The count of initial spill slots in @p ssenv->slots
620 * This also is the size of the preallocated array @p ass
622 * @return An array of spill slots @p ass in specific order
624 static void optimize_slots(ss_env_t *ssenv, int size, spill_slot_t *ass[]) {
625 int i, o, used_slots;
629 pmap_foreach(ssenv->slots, entr)
630 ass[i++] = entr->value;
632 /* Sort the array to minimize fragmentation and cache footprint.
633 Large slots come first */
634 qsort(ass, size, sizeof(ass[0]), ss_sorter);
636 /* For each spill slot:
637 - assign a new offset to this slot
638 - xor find another slot to coalesce with */
640 for (i=0; i<size; ++i) { /* for each spill slot */
644 DBG((ssenv->dbg, LEVEL_1, "Spill slot %d members:\n", i));
645 for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
646 DBG((ssenv->dbg, LEVEL_1, " %+F\n", n1));
649 for (o=0; o < used_slots && tgt_slot == -1; ++o) { /* for each offset-assigned spill slot */
650 /* check inter-slot-pairs for interference */
652 for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
653 for(n2 = pset_first(ass[o]->members); n2; n2 = pset_next(ass[o]->members))
654 if(values_interfere(n1, n2)) {
655 pset_break(ass[i]->members);
656 pset_break(ass[o]->members);
657 DBG((ssenv->dbg, LEVEL_1, " Interf %+F -- %+F\n", n1, n2));
658 goto interf_detected;
661 /* if we are here, there is no interference between ass[i] and ass[o] */
664 interf_detected: /*nothing*/ ;
667 /* now the members of ass[i] join the members of ass[tgt_slot] */
669 /* do we need a new slot? */
670 if (tgt_slot == -1) {
671 tgt_slot = used_slots;
676 ass[tgt_slot]->size = ass[i]->size;
677 del_pset(ass[tgt_slot]->members);
678 ass[tgt_slot]->members = pset_new_ptr(8);
682 /* copy the members to the target pset */
683 /* NOTE: If src and tgt pset are the same, inserting while iterating is not allowed */
685 for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
686 pset_insert_ptr(ass[tgt_slot]->members, n1);
690 #define ALIGN_SPILL_AREA 16
691 #define pset_foreach(pset, elm) for(elm=pset_first(pset); elm; elm=pset_next(pset))
694 * Returns a spill type for a mode. Keep them in a map to reduce
695 * the number of types.
697 * @param types a map containing all created types
698 * @param ss the spill slot
700 * Note that type types should are identical for every mode.
701 * This rule might break if two different register classes return the same
702 * mode but different alignments.
704 static ir_type *get_spill_type(pmap *types, spill_slot_t *ss) {
705 pmap_entry *e = pmap_find(types, ss->largest_mode);
710 snprintf(buf, sizeof(buf), "spill_slot_type_%s", get_mode_name(ss->largest_mode));
711 res = new_type_primitive(new_id_from_str(buf), ss->largest_mode);
712 set_type_alignment_bytes(res, ss->align);
713 pmap_insert(types, ss->largest_mode, res);
717 assert(get_type_alignment_bytes(res) == (int)ss->align);
723 * Create spill slot entities on the frame type.
725 * @param ssenv the spill environment
726 * @param n number of spill slots
727 * @param ss array of spill slots
729 static void assign_entities(ss_env_t *ssenv, int n_slots, spill_slot_t *ss[]) {
730 int i, offset, frame_align;
731 ir_type *frame = get_irg_frame_type(ssenv->cenv->irg);
733 /* aligning by increasing frame size */
734 offset = get_type_size_bits(frame) / 8;
735 offset = round_up2(offset, ALIGN_SPILL_AREA);
736 set_type_size_bytes(frame, -1);
738 /* create entities and assign offsets according to size and alignment*/
739 for (i = 0; i < n_slots; ++i) {
746 snprintf(buf, sizeof(buf), "spill_slot_%d", i);
747 name = new_id_from_str(buf);
749 spill_ent = new_entity(frame, name, get_spill_type(ssenv->types, ss[i]));
752 offset = round_up2(offset, ss[i]->align);
754 set_entity_offset_bytes(spill_ent, offset);
755 /* next possible offset */
756 offset += round_up2(ss[i]->size, ss[i]->align);
758 pset_foreach(ss[i]->members, irn)
759 be_set_Spill_entity(irn, spill_ent);
762 /* set final size of stack frame */
763 frame_align = get_type_alignment_bytes(frame);
764 set_type_size_bytes(frame, round_up2(offset, frame_align));
767 void be_compute_spill_offsets(be_chordal_env_t *cenv) {
773 obstack_init(&ssenv.ob);
775 ssenv.slots = pmap_create();
776 ssenv.types = pmap_create();
777 FIRM_DBG_REGISTER(ssenv.dbg, "ir.be.spillslots");
779 /* Get initial spill slots */
780 irg_walk_graph(cenv->irg, NULL, compute_spill_slots_walker, &ssenv);
782 /* Build an empty array for optimized spill slots */
783 ss_size = pmap_count(ssenv.slots);
784 ss = obstack_alloc(&ssenv.ob, ss_size * sizeof(*ss));
785 optimize_slots(&ssenv, ss_size, ss);
787 /* Integrate slots into the stack frame entity */
788 assign_entities(&ssenv, ss_size, ss);
791 pmap_foreach(ssenv.slots, pme)
792 del_pset(((spill_slot_t *)pme->value)->members);
793 pmap_destroy(ssenv.slots);
794 pmap_destroy(ssenv.types);
795 obstack_free(&ssenv.ob, NULL);
797 be_copy_entities_to_reloads(cenv->irg);