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;)
67 * compare two spill contexts.
69 static int cmp_spillctx(const void *a, const void *b, size_t n) {
70 const spill_ctx_t *p = a;
71 const spill_ctx_t *q = b;
72 return p->user != q->user || p->spilled != q->spilled;
76 * Compare two spill infos.
78 static int cmp_spillinfo(const void *x, const void *y, size_t size) {
79 const spill_info_t *xx = x;
80 const spill_info_t *yy = y;
81 return xx->spilled_node != yy->spilled_node;
85 /* Sets the debug module of a spill environment. */
86 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
91 /* Creates a new spill environment. */
92 spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env, decide_irn_t is_mem_phi, void *data) {
93 spill_env_t *env = xmalloc(sizeof(env[0]));
94 env->spill_ctxs = new_set(cmp_spillctx, 1024);
95 env->spills = new_set(cmp_spillinfo, 1024);
96 env->cls = chordal_env->cls;
97 env->is_mem_phi = is_mem_phi;
99 env->chordal_env = chordal_env;
100 obstack_init(&env->obst);
104 /* Deletes a spill environment. */
105 void be_delete_spill_env(spill_env_t *senv) {
106 del_set(senv->spill_ctxs);
107 del_set(senv->spills);
108 obstack_free(&senv->obst, NULL);
113 * Returns a spill context. If the context did not exists, create one.
115 * @param sc the set containing all spill contexts
116 * @param to_spill the node that should be spilled
117 * @param ctx_irn an user of the spilled node
119 * @return a spill context.
121 static spill_ctx_t *be_get_spill_ctx(set *sc, ir_node *to_spill, ir_node *ctx_irn) {
124 templ.spilled = to_spill;
125 templ.user = ctx_irn;
128 return set_insert(sc, &templ, sizeof(templ), HASH_COMBINE(HASH_PTR(to_spill), HASH_PTR(ctx_irn)));
134 * @param senv the spill environment
135 * @param irn the node that should be spilled
136 * @param ctx_irn an user of the spilled node
138 * @return a be_Spill node
140 static ir_node *be_spill_irn(spill_env_t *senv, ir_node *irn, ir_node *ctx_irn) {
142 DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", irn, ctx_irn));
144 ctx = be_get_spill_ctx(senv->spill_ctxs, irn, ctx_irn);
146 const be_main_env_t *env = senv->chordal_env->birg->main_env;
147 ctx->spill = be_spill(env->arch_env, irn, ctx_irn);
154 * If the first usage of a Phi result would be out of memory
155 * there is no sense in allocating a register for it.
156 * Thus we spill it and all its operands to the same spill slot.
157 * Therefore the phi/dataB becomes a phi/Memory
159 * @param senv the spill environment
160 * @param phi the Phi node that should be spilled
161 * @param ctx_irn an user of the spilled node
163 * @return a be_Spill node
165 static ir_node *be_spill_phi(spill_env_t *senv, ir_node *phi, ir_node *ctx_irn) {
166 int i, n = get_irn_arity(phi);
167 ir_node **ins, *bl = get_nodes_block(phi);
168 ir_graph *irg = senv->chordal_env->irg;
172 DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", phi, ctx_irn));
174 /* search an existing spill for this context */
175 ctx = be_get_spill_ctx(senv->spill_ctxs, phi, ctx_irn);
177 /* if not found spill the phi */
179 /* build a new PhiM */
180 NEW_ARR_A(ir_node *, ins, n);
181 for (i=0; i<n; ++i) {
182 ir_node *arg = get_irn_n(phi, i);
185 if(is_Phi(arg) && pset_find_ptr(senv->mem_phis, arg))
186 sub_res = be_spill_phi(senv, arg, ctx_irn);
188 sub_res = be_spill_irn(senv, arg, ctx_irn);
191 ctx->spill = new_r_Phi(senv->chordal_env->irg, bl, n, ins, mode_M);
199 * @param senv the spill environment
200 * @param irn the node that should be spilled
201 * @param ctx_irn an user of the spilled node
203 * @return a be_Spill node
205 static ir_node *be_spill_node(spill_env_t *senv, ir_node *to_spill) {
207 if (pset_find_ptr(senv->mem_phis, to_spill))
208 res = be_spill_phi(senv, to_spill, to_spill);
210 res = be_spill_irn(senv, to_spill, to_spill);
220 * Check if a spilled node could be rematerialized.
222 * @param senv the spill environment
223 * @param spill the Spill node
224 * @param spilled the node that was spilled
225 * @param reloader a irn that requires a reload
227 static int check_remat_conditions(spill_env_t *senv, ir_node *spill, ir_node *spilled, ir_node *reloader) {
230 /* check for 'normal' spill and general remat condition */
231 if (!be_is_Spill(spill) || !arch_irn_is(senv->chordal_env->birg->main_env->arch_env, spilled, rematerializable))
234 /* check availability of original arguments */
235 if (is_Block(reloader)) {
237 /* we want to remat at the end of a block.
238 * thus all arguments must be alive at the end of the block
240 for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
241 ir_node *arg = get_irn_n(spilled, pos);
242 if (!is_live_end(reloader, arg))
248 /* we want to remat before the insn reloader
249 * thus an arguments is alive if
250 * - it interferes with the reloaders result
252 * - or it is (last-) used by reloader itself
254 for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
255 ir_node *arg = get_irn_n(spilled, pos);
258 if (values_interfere(reloader, arg))
261 for (i=0, m=get_irn_arity(reloader); i<m; ++i) {
262 ir_node *rel_arg = get_irn_n(reloader, i);
267 /* arg is not alive before reloader */
279 #else /* BUGGY_REMAT */
282 * A very simple rematerialization checker.
284 * @param senv the spill environment
285 * @param spill the Spill node
286 * @param spilled the node that was spilled
287 * @param reloader a irn that requires a reload
289 static int check_remat_conditions(spill_env_t *senv, ir_node *spill, ir_node *spilled, ir_node *reloader) {
290 const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
292 return get_irn_arity(spilled) == 0 &&
293 be_is_Spill(spill) &&
294 arch_irn_is(aenv, spilled, rematerializable);
297 #endif /* BUGGY_REMAT */
302 * Re-materialize a node.
304 * @param senv the spill environment
305 * @param spilled the node that was spilled
306 * @param reloader a irn that requires a reload
308 static ir_node *do_remat(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
310 ir_node *bl = (is_Block(reloader)) ? reloader : get_nodes_block(reloader);
312 /* recompute the value */
313 res = new_ir_node(get_irn_dbg_info(spilled), senv->chordal_env->irg, bl,
315 get_irn_mode(spilled),
316 get_irn_arity(spilled),
317 get_irn_in(spilled) + 1);
318 copy_node_attr(spilled, res);
320 DBG((senv->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
322 /* insert in schedule */
323 if (is_Block(reloader)) {
324 ir_node *insert = sched_skip(reloader, 0, sched_skip_cf_predicator, (void *) senv->chordal_env->birg->main_env->arch_env);
325 sched_add_after(insert, res);
327 sched_add_before(reloader, res);
334 * Walker: fills the mem_phis set by evaluating Phi nodes
335 * using the is_mem_phi() callback.
337 static void phi_walker(ir_node *irn, void *env) {
338 spill_env_t *senv = env;
341 const arch_env_t *arch = senv->chordal_env->birg->main_env->arch_env;
342 if (arch_irn_has_reg_class(arch, irn, 0, senv->cls) &&
343 senv->is_mem_phi(irn, senv->data)) {
344 DBG((senv->dbg, LEVEL_1, " %+F\n", irn));
345 pset_insert_ptr(senv->mem_phis, irn);
350 void be_insert_spills_reloads(spill_env_t *senv, pset *reload_set) {
351 const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
352 ir_graph *irg = senv->chordal_env->irg;
357 /* get all special spilled phis */
358 DBG((senv->dbg, LEVEL_1, "Mem-phis:\n"));
359 senv->mem_phis = pset_new_ptr_default();
360 irg_walk_graph(senv->chordal_env->irg, phi_walker, NULL, senv);
362 /* Add reloads for mem_phis */
363 /* BETTER: These reloads (1) should only be inserted, if they are really needed */
364 DBG((senv->dbg, LEVEL_1, "Reloads for mem-phis:\n"));
365 for(irn = pset_first(senv->mem_phis); irn; irn = pset_next(senv->mem_phis)) {
367 DBG((senv->dbg, LEVEL_1, " Mem-phi %+F\n", irn));
368 foreach_out_edge(irn, e) {
369 ir_node *user = e->src;
370 if (is_Phi(user) && !pset_find_ptr(senv->mem_phis, user)) {
371 ir_node *use_bl = get_nodes_block(user);
372 DBG((senv->dbg, LEVEL_1, " non-mem-phi user %+F\n", user));
373 be_add_reload_on_edge(senv, irn, use_bl, e->pos); /* (1) */
378 /* process each spilled node */
379 DBG((senv->dbg, LEVEL_1, "Insert spills and reloads:\n"));
380 possibly_dead = new_pdeq();
381 for(si = set_first(senv->spills); si; si = set_next(senv->spills)) {
383 ir_mode *mode = get_irn_mode(si->spilled_node);
384 pset *values = pset_new_ptr(16);
386 /* go through all reloads for this spill */
387 for(rld = si->reloaders; rld; rld = rld->next) {
390 /* the spill for this reloader */
391 ir_node *spill = be_spill_node(senv, si->spilled_node);
394 if (check_remat_conditions(senv, spill, si->spilled_node, rld->reloader)) {
395 new_val = do_remat(senv, si->spilled_node, rld->reloader);
396 pdeq_putl(possibly_dead, spill);
401 new_val = be_reload(aenv, senv->cls, rld->reloader, mode, spill);
403 DBG((senv->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
404 pset_insert_ptr(values, new_val);
406 pset_insert_ptr(reload_set, new_val);
409 /* introduce copies, rewire the uses */
410 assert(pset_count(values) > 0 && "???");
411 pset_insert_ptr(values, si->spilled_node);
412 be_ssa_constr_set_ignore(senv->chordal_env->dom_front, values, senv->mem_phis);
417 foreach_pset(senv->mem_phis, irn) {
419 for (i = 0, n = get_irn_arity(irn); i < n; ++i) {
420 pdeq_putl(possibly_dead, get_irn_n(irn, i));
421 set_irn_n(irn, i, new_r_Bad(senv->chordal_env->irg));
426 /* check if possibly dead nodes are really dead yet */
427 while (! pdeq_empty(possibly_dead)) {
428 ir_node *irn = pdeq_getr(possibly_dead);
429 const ir_edge_t *edge = get_irn_out_edge_first(irn);
433 for (i = get_irn_arity(irn) - 1; i >= 0; --i) {
434 pdeq_putl(possibly_dead, get_irn_n(irn, i));
435 set_irn_n(irn, i, new_r_Bad(senv->chordal_env->irg));
440 del_pdeq(possibly_dead);
441 del_pset(senv->mem_phis);
444 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before) {
445 spill_info_t templ, *res;
448 templ.spilled_node = to_spill;
449 templ.reloaders = NULL;
450 res = set_insert(senv->spills, &templ, sizeof(templ), HASH_PTR(to_spill));
452 rel = obstack_alloc(&senv->obst, sizeof(rel[0]));
453 rel->reloader = before;
454 rel->next = res->reloaders;
455 res->reloaders = rel;
458 void be_add_reload_on_edge(spill_env_t *senv, ir_node *to_spill, ir_node *bl, int pos) {
459 ir_node *insert_bl = get_irn_arity(bl) == 1 ? sched_first(bl) : get_Block_cfgpred_block(bl, pos);
460 be_add_reload(senv, to_spill, insert_bl);
465 /****************************************
467 SPILL SLOT MANAGEMENT AND OPTS
469 ****************************************/
471 typedef struct _spill_slot_t {
475 ir_mode *largest_mode; /* the mode of all members with largest size */
478 typedef struct _ss_env_t {
480 be_chordal_env_t *cenv;
481 pmap *slots; /* maps spill_contexts to spill_slots */
482 pmap *types; /* maps modes to types */
483 DEBUG_ONLY(firm_dbg_module_t *dbg;)
488 * Walker: compute the spill slots
490 static void compute_spill_slots_walker(ir_node *spill, void *env) {
491 ss_env_t *ssenv = env;
496 if (!be_is_Spill(spill))
499 /* check, if this spill is for a context already known */
500 ctx = be_get_Spill_context(spill);
501 entry = pmap_find(ssenv->slots, ctx);
504 struct _arch_env_t *arch_env = ssenv->cenv->birg->main_env->arch_env;
505 const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
506 ir_mode *largest_mode = arch_register_class_mode(cls);
508 /* this is a new spill context */
509 ss = obstack_alloc(&ssenv->ob, sizeof(*ss));
510 ss->members = pset_new_ptr(8);
511 ss->largest_mode = largest_mode;
512 ss->size = get_mode_size_bytes(ss->largest_mode);
513 ss->align = arch_isa_get_reg_class_alignment(arch_env->isa, cls);
514 pmap_insert(ssenv->slots, ctx, ss);
516 /* values with the same spill_ctx must go into the same spill slot */
520 /* ugly mega assert :-) */
523 struct _arch_env_t *arch_env = ssenv->cenv->birg->main_env->arch_env;
524 const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
525 int size = get_mode_size_bytes(arch_register_class_mode(cls));
526 assert(ss->size == size && "Different sizes for the same spill slot are not allowed.");
527 for (irn = pset_first(ss->members); irn; irn = pset_next(ss->members)) {
528 /* use values_interfere here, because it uses the dominance check,
529 which does work for values in memory */
530 assert(!values_interfere(spill, irn) && "Spills for the same spill slot must not interfere!");
536 pset_insert_ptr(ss->members, spill);
540 * qsort compare function, sort spill slots by size.
542 static int ss_sorter(const void *v1, const void *v2) {
543 const spill_slot_t **ss1 = v1;
544 const spill_slot_t **ss2 = v2;
545 return ((int) (*ss2)->size) - ((int) (*ss1)->size);
550 * This function should optimize the spill slots.
551 * - Coalescing of multiple slots
552 * - Ordering the slots
554 * Input slots are in @p ssenv->slots
555 * @p size The count of initial spill slots in @p ssenv->slots
556 * This also is the size of the preallocated array @p ass
558 * @return An array of spill slots @p ass in specific order
560 static void optimize_slots(ss_env_t *ssenv, int size, spill_slot_t *ass[]) {
561 int i, o, used_slots;
565 pmap_foreach(ssenv->slots, entr)
566 ass[i++] = entr->value;
568 /* Sort the array to minimize fragmentation and cache footprint.
569 Large slots come first */
570 qsort(ass, size, sizeof(ass[0]), ss_sorter);
572 /* For each spill slot:
573 - assign a new offset to this slot
574 - xor find another slot to coalesce with */
576 for (i=0; i<size; ++i) { /* for each spill slot */
580 DBG((ssenv->dbg, LEVEL_1, "Spill slot %d members:\n", i));
581 for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
582 DBG((ssenv->dbg, LEVEL_1, " %+F\n", n1));
585 for (o=0; o < used_slots && tgt_slot == -1; ++o) { /* for each offset-assigned spill slot */
586 /* check inter-slot-pairs for interference */
588 for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
589 for(n2 = pset_first(ass[o]->members); n2; n2 = pset_next(ass[o]->members))
590 if(values_interfere(n1, n2)) {
591 pset_break(ass[i]->members);
592 pset_break(ass[o]->members);
593 DBG((ssenv->dbg, LEVEL_1, " Interf %+F -- %+F\n", n1, n2));
594 goto interf_detected;
597 /* if we are here, there is no interference between ass[i] and ass[o] */
600 interf_detected: /*nothing*/ ;
603 /* now the members of ass[i] join the members of ass[tgt_slot] */
605 /* do we need a new slot? */
606 if (tgt_slot == -1) {
607 tgt_slot = used_slots;
612 ass[tgt_slot]->size = ass[i]->size;
613 del_pset(ass[tgt_slot]->members);
614 ass[tgt_slot]->members = pset_new_ptr(8);
618 /* copy the members to the target pset */
619 /* NOTE: If src and tgt pset are the same, inserting while iterating is not allowed */
621 for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
622 pset_insert_ptr(ass[tgt_slot]->members, n1);
626 #define ALIGN_SPILL_AREA 16
627 #define pset_foreach(pset, elm) for(elm=pset_first(pset); elm; elm=pset_next(pset))
630 * Returns a spill type for a mode. Keep them in a map to reduce
631 * the number of types.
633 * @param types a map containing all created types
634 * @param ss the spill slot
636 * Note that type types should are identical for every mode.
637 * This rule might break if two different register classes return the same
638 * mode but different alignments.
640 static ir_type *get_spill_type(pmap *types, spill_slot_t *ss) {
641 pmap_entry *e = pmap_find(types, ss->largest_mode);
646 snprintf(buf, sizeof(buf), "spill_slot_type_%s", get_mode_name(ss->largest_mode));
647 res = new_type_primitive(new_id_from_str(buf), ss->largest_mode);
648 set_type_alignment_bytes(res, ss->align);
649 pmap_insert(types, ss->largest_mode, res);
653 assert(get_type_alignment_bytes(res) == (int)ss->align);
659 * Create spill slot entities on the frame type.
661 * @param ssenv the spill environment
662 * @param n number of spill slots
663 * @param ss array of spill slots
665 static void assign_entities(ss_env_t *ssenv, int n_slots, spill_slot_t *ss[]) {
666 int i, offset, frame_align;
667 ir_type *frame = get_irg_frame_type(ssenv->cenv->irg);
669 /* aligning by increasing frame size */
670 offset = get_type_size_bits(frame) / 8;
671 offset = round_up2(offset, ALIGN_SPILL_AREA);
672 set_type_size_bytes(frame, -1);
674 /* create entities and assign offsets according to size and alignment*/
675 for (i = 0; i < n_slots; ++i) {
682 snprintf(buf, sizeof(buf), "spill_slot_%d", i);
683 name = new_id_from_str(buf);
685 spill_ent = new_entity(frame, name, get_spill_type(ssenv->types, ss[i]));
688 offset = round_up2(offset, ss[i]->align);
690 set_entity_offset_bytes(spill_ent, offset);
691 /* next possible offset */
692 offset += round_up2(ss[i]->size, ss[i]->align);
694 pset_foreach(ss[i]->members, irn)
695 be_set_Spill_entity(irn, spill_ent);
698 /* set final size of stack frame */
699 frame_align = get_type_alignment_bytes(frame);
700 set_type_size_bytes(frame, round_up2(offset, frame_align));
703 void be_compute_spill_offsets(be_chordal_env_t *cenv) {
709 obstack_init(&ssenv.ob);
711 ssenv.slots = pmap_create();
712 ssenv.types = pmap_create();
713 FIRM_DBG_REGISTER(ssenv.dbg, "ir.be.spillslots");
715 /* Get initial spill slots */
716 irg_walk_graph(cenv->irg, NULL, compute_spill_slots_walker, &ssenv);
718 /* Build an empty array for optimized spill slots */
719 ss_size = pmap_count(ssenv.slots);
720 ss = obstack_alloc(&ssenv.ob, ss_size * sizeof(*ss));
721 optimize_slots(&ssenv, ss_size, ss);
723 /* Integrate slots into the stack frame entity */
724 assign_entities(&ssenv, ss_size, ss);
727 pmap_foreach(ssenv.slots, pme)
728 del_pset(((spill_slot_t *)pme->value)->members);
729 pmap_destroy(ssenv.slots);
730 pmap_destroy(ssenv.types);
731 obstack_free(&ssenv.ob, NULL);
733 be_copy_entities_to_reloads(cenv->irg);