2 * Author: Matthias Braun
4 * Copyright: (c) Universitaet Karlsruhe
5 * License: This file is protected by GPL - GNU GENERAL PUBLIC LICENSE.
12 #include "bespillmorgan.h"
14 #include "bechordal_t.h"
22 #include "irgraph_t.h"
26 #include "bespillbelady.h"
28 #include "benodesets.h"
32 #define DBG_PRESSURE 4
34 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
36 typedef struct morgan_env {
37 const be_chordal_env_t *cenv;
38 const arch_env_t *arch;
39 const arch_register_class_t *cls;
42 /** maximum safe register pressure */
43 int registers_available;
51 typedef struct loop_edge {
56 typedef struct loop_attr {
60 /** The set of all values that are live in the loop but not used in the loop */
61 bitset_t *livethrough_unused;
64 typedef struct block_attr {
66 /** set of all values that are live in the block but not used in the block */
67 bitset_t *livethrough_unused;
70 //---------------------------------------------------------------------------
72 static int loop_edge_cmp(const void* p1, const void* p2, size_t s) {
73 loop_edge_t *e1 = (loop_edge_t*) p1;
74 loop_edge_t *e2 = (loop_edge_t*) p2;
76 return e1->block != e2->block || e1->pos != e2->pos;
79 static int loop_attr_cmp(const void *e1, const void *e2, size_t s) {
80 loop_attr_t *la1 = (loop_attr_t*) e1;
81 loop_attr_t *la2 = (loop_attr_t*) e2;
83 return la1->loop != la2->loop;
86 static int block_attr_cmp(const void *e1, const void *e2, size_t s) {
87 block_attr_t *b1 = (block_attr_t*) e1;
88 block_attr_t *b2 = (block_attr_t*) e2;
90 return b1->block != b2->block;
93 static INLINE int loop_attr_hash(const loop_attr_t *a) {
95 return a->loop->loop_nr;
97 return HASH_PTR(a->loop);
101 static INLINE int block_attr_hash(const block_attr_t *b) {
102 return nodeset_hash(b->block);
105 static INLINE int loop_edge_hash(const loop_edge_t *e) {
106 return nodeset_hash(e->block) ^ (e->pos * 31);
109 static INLINE loop_attr_t *get_loop_attr(morgan_env_t *env, const ir_loop *loop) {
110 loop_attr_t l_attr, *res;
114 hash = loop_attr_hash(&l_attr);
115 res = set_find(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
117 // create new loop_attr if none exists yet
119 l_attr.out_edges = new_set(loop_edge_cmp, 1);
120 l_attr.in_edges = new_set(loop_edge_cmp, 1);
121 l_attr.livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
122 res = set_insert(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
128 static INLINE block_attr_t *get_block_attr(morgan_env_t *env, const ir_node *block) {
129 block_attr_t b_attr, *res;
131 b_attr.block = block;
133 hash = block_attr_hash(&b_attr);
134 res = set_find(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
137 b_attr.livethrough_unused = NULL;
138 res = set_insert(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
144 //---------------------------------------------------------------------------
146 static INLINE int consider_for_spilling(const arch_env_t *env, const arch_register_class_t *cls, const ir_node *node) {
147 if(!arch_irn_has_reg_class(env, node, -1, cls))
150 return !(arch_irn_get_flags(env, node) & (arch_irn_flags_ignore | arch_irn_flags_dont_spill));
154 * Determine edges going out of a loop (= edges that go to a block that is not inside
155 * the loop or one of its subloops)
157 static INLINE void construct_loop_edges(ir_node* block, void* data) {
158 morgan_env_t *env = data;
159 int n_cfgpreds = get_Block_n_cfgpreds(block);
161 ir_loop* loop = get_irn_loop(block);
162 DBG((dbg, DBG_LOOPANA, "Loop for %+F: %d (depth %d)\n", block, loop->loop_nr, loop->depth));
164 for(i = 0; i < n_cfgpreds; ++i) {
167 ir_node* cfgpred = get_Block_cfgpred(block, i);
168 ir_node* cfgpred_block = get_nodes_block(cfgpred);
169 ir_loop* cfgpred_loop = get_irn_loop(cfgpred_block);
171 if(cfgpred_loop == loop)
174 assert(get_loop_depth(cfgpred_loop) != get_loop_depth(loop));
178 hash = loop_edge_hash(&edge);
180 // edge out of a loop?
181 if(get_loop_depth(cfgpred_loop) > get_loop_depth(loop)) {
184 DBG((dbg, DBG_LOOPANA, "Loop out edge from %+F (loop %d) to %+F (loop %d)\n", block, get_loop_loop_nr(loop),
185 cfgpred_block, get_loop_loop_nr(cfgpred_loop)));
187 /* this might be a jump out of multiple loops, so add this to all
188 * needed outedge sets */
191 loop_attr_t *l_attr = get_loop_attr(env, l);
192 set_insert(l_attr->out_edges, &edge, sizeof(edge), hash);
194 l = get_loop_outer_loop(l);
201 DBG((dbg, DBG_LOOPANA, "Loop in edge from %+F (loop %d) to %+F (loop %d)\n", block, get_loop_loop_nr(loop),
202 cfgpred_block, get_loop_loop_nr(cfgpred_loop)));
206 loop_attr_t *l_attr = get_loop_attr(env, l);
207 set_insert(l_attr->in_edges, &edge, sizeof(edge), hash);
209 l = get_loop_outer_loop(l);
210 } while(l != cfgpred_loop);
215 static void free_loop_edges(morgan_env_t *env) {
218 for(l_attr = set_first(env->loop_attr_set); l_attr != NULL; l_attr = set_next(env->loop_attr_set)) {
219 del_set(l_attr->out_edges);
220 del_set(l_attr->in_edges);
226 * Debugging help, shows all nodes in a (node-)bitset
228 static void show_nodebitset(ir_graph* irg, const bitset_t* bitset) {
231 bitset_foreach(bitset, i) {
232 ir_node* node = get_idx_irn(irg, i);
233 ir_fprintf(stderr, " %+F", node);
235 fprintf(stderr, "\n");
239 static INLINE void init_livethrough_unuseds(block_attr_t *attr, morgan_env_t *env) {
240 const ir_node *block;
243 if(attr->livethrough_unused != NULL)
248 attr->livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
250 // copy all live-outs into the livethrough_unused set
251 be_lv_foreach(env->cenv->lv, block, be_lv_state_in | be_lv_state_out, i) {
252 ir_node *irn = be_lv_get_irn(env->cenv->lv, block, i);
255 if(!consider_for_spilling(env->arch, env->cls, irn))
258 node_idx = get_irn_idx(irn);
259 bitset_set(attr->livethrough_unused, node_idx);
264 * Construct the livethrough unused set for a block
266 static void construct_block_livethrough_unused(ir_node *block, void *data) {
267 morgan_env_t* env = data;
268 block_attr_t *block_attr = get_block_attr(env, block);
271 block_attr_t **pred_attrs = NULL;
274 init_livethrough_unuseds(block_attr, env);
276 DBG((dbg, DBG_LIVE, "Processing block %d\n", get_irn_node_nr(block)));
278 n_cfgpreds = get_Block_n_cfgpreds(block);
280 pred_attrs = alloca(sizeof(pred_attrs[0]) * n_cfgpreds);
281 for(i = 0; i < n_cfgpreds; ++i) {
282 ir_node *pred_block = get_Block_cfgpred_block(block, i);
283 pred_attrs[i] = get_block_attr(env, pred_block);
284 init_livethrough_unuseds(pred_attrs[i], env);
289 * All values that are used within the block are not unused (and therefore not
290 * livethrough_unused)
292 sched_foreach(block, node) {
295 // phis are really uses in the pred block
298 for(j = 0; j < n_cfgpreds; ++j) {
299 ir_node *used_value = get_Phi_pred(node, j);
300 int idx = get_irn_idx(used_value);
301 block_attr_t *pred_attr = pred_attrs[j];
303 bitset_clear(pred_attr->livethrough_unused, idx);
306 // mark all used values as used
307 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
308 int idx = get_irn_idx(get_irn_n(node, i));
309 bitset_clear(block_attr->livethrough_unused, idx);
316 * Construct the livethrough unused set for a loop (and all its subloops+blocks)
318 static bitset_t *construct_loop_livethrough_unused(morgan_env_t *env, const ir_loop *loop) {
320 loop_attr_t* loop_attr = get_loop_attr(env, loop);
322 DBG((dbg, DBG_LIVE, "Processing Loop %d\n", loop->loop_nr));
323 assert(get_loop_n_elements(loop) > 0);
324 for(i = 0; i < get_loop_n_elements(loop); ++i) {
325 loop_element elem = get_loop_element(loop, i);
326 switch (*elem.kind) {
328 ir_node *block = elem.node;
329 block_attr_t *block_attr = get_block_attr(env, block);
330 bitset_t *livethrough_block_unused = block_attr->livethrough_unused;
332 assert(is_Block(elem.node));
333 assert(livethrough_block_unused != NULL);
336 bitset_copy(loop_attr->livethrough_unused, livethrough_block_unused);
338 bitset_and(loop_attr->livethrough_unused, livethrough_block_unused);
343 bitset_t *livethrough_son_unused;
345 livethrough_son_unused = construct_loop_livethrough_unused(env, elem.son);
347 bitset_copy(loop_attr->livethrough_unused, livethrough_son_unused);
349 bitset_and(loop_attr->livethrough_unused, livethrough_son_unused);
358 DBG((dbg, DBG_LIVE, "Done with loop %d\n", loop->loop_nr));
360 // remove all unused livethroughs that are remembered for this loop from child loops and blocks
361 for(i = 0; i < get_loop_n_elements(loop); ++i) {
362 const loop_element elem = get_loop_element(loop, i);
364 if(*elem.kind == k_ir_loop) {
365 loop_attr_t *son_attr = get_loop_attr(env, elem.son);
366 bitset_andnot(son_attr->livethrough_unused, loop_attr->livethrough_unused);
368 DBG((dbg, DBG_LIVE, "Livethroughs for loop %d:\n", loop->loop_nr));
369 } else if(*elem.kind == k_ir_node) {
370 block_attr_t *block_attr = get_block_attr(env, elem.node);
371 bitset_andnot(block_attr->livethrough_unused, loop_attr->livethrough_unused);
373 DBG((dbg, DBG_LIVE, "Livethroughs for block %+F\n", elem.node));
379 return loop_attr->livethrough_unused;
382 /*---------------------------------------------------------------------------*/
384 static int reduce_register_pressure_in_block(morgan_env_t *env, const ir_node* block, int loop_unused_spills_possible) {
387 int loop_unused_spills_needed;
388 pset *live_nodes = pset_new_ptr_default();
390 be_liveness_end_of_block(env->cenv->lv, env->arch, env->cls, block, live_nodes);
391 max_pressure = pset_count(live_nodes);
393 DBG((dbg, DBG_LIVE, "Reduce pressure to %d In Block %+F:\n", env->registers_available, block));
396 * Determine register pressure in block
398 sched_foreach_reverse(block, node) {
404 be_liveness_transfer(env->arch, env->cls, node, live_nodes);
405 pressure = pset_count(live_nodes);
406 if(pressure > max_pressure)
407 max_pressure = pressure;
409 del_pset(live_nodes);
411 DBG((dbg, DBG_PRESSURE, "\tMax Pressure in %+F: %d\n", block, max_pressure));
413 loop_unused_spills_needed = max_pressure - env->registers_available;
415 if(loop_unused_spills_needed < 0) {
416 loop_unused_spills_needed = 0;
417 } else if(loop_unused_spills_needed > loop_unused_spills_possible) {
418 loop_unused_spills_needed = loop_unused_spills_possible;
421 DBG((dbg, DBG_PRESSURE, "Unused spills for Block %+F needed: %d\n", block, loop_unused_spills_needed));
422 return loop_unused_spills_needed;
426 * Reduce register pressure in a loop
428 * @param unused_spills_possible Number of spills from livethrough_unused variables possible in outer loops
429 * @return Number of spills of livethrough_unused variables needed in outer loops
431 static int reduce_register_pressure_in_loop(morgan_env_t *env, const ir_loop *loop, int outer_spills_possible) {
433 loop_attr_t* loop_attr = get_loop_attr(env, loop);
434 int spills_needed = 0;
435 int spills_possible = outer_spills_possible + bitset_popcnt(loop_attr->livethrough_unused);
436 int outer_spills_needed;
438 DBG((dbg, DBG_PRESSURE, "Reducing Pressure in loop %d\n", loop->loop_nr));
439 for(i = 0; i < get_loop_n_elements(loop); ++i) {
440 loop_element elem = get_loop_element(loop, i);
441 switch (*elem.kind) {
444 assert(is_Block(elem.node));
445 needed = reduce_register_pressure_in_block(env, elem.node, spills_possible);
447 assert(needed <= spills_possible);
448 if(needed > spills_needed)
449 spills_needed = needed;
453 int needed = reduce_register_pressure_in_loop(env, elem.son, spills_possible);
455 assert(needed <= spills_possible);
456 if(needed > spills_needed)
457 spills_needed = needed;
466 /* calculate number of spills needed in outer loop and spill
467 * unused livethrough nodes around this loop
469 if(spills_needed > outer_spills_possible) {
471 outer_spills_needed = outer_spills_possible;
472 spills_needed -= outer_spills_possible;
474 spills_to_place = spills_needed;
476 DBG((dbg, DBG_SPILLS, "%d values unused in loop %d, spilling %d\n",
477 spills_possible - outer_spills_possible, loop->loop_nr, spills_to_place));
479 bitset_foreach(loop_attr->livethrough_unused, i) {
481 ir_node *to_spill = get_idx_irn(env->irg, i);
483 DBG((dbg, DBG_SPILLS, "Spilling node %+F around loop %d\n", to_spill, loop->loop_nr));
485 for(edge = set_first(loop_attr->out_edges); edge != NULL; edge = set_next(loop_attr->out_edges)) {
486 be_add_reload_on_edge(env->senv, to_spill, edge->block, edge->pos);
490 if(spills_to_place <= 0) {
495 outer_spills_needed = spills_needed;
498 return outer_spills_needed;
501 void be_spill_morgan(be_chordal_env_t *chordal_env) {
504 FIRM_DBG_REGISTER(dbg, "ir.be.spillmorgan");
505 //firm_dbg_set_mask(dbg, DBG_SPILLS | DBG_LOOPANA);
507 env.cenv = chordal_env;
508 env.arch = chordal_env->birg->main_env->arch_env;
509 env.irg = chordal_env->irg;
510 env.cls = chordal_env->cls;
511 env.senv = be_new_spill_env(chordal_env);
512 DEBUG_ONLY(be_set_spill_env_dbg_module(env.senv, dbg);)
514 obstack_init(&env.obst);
516 env.registers_available = env.cls->n_regs - be_put_ignore_regs(chordal_env->birg, env.cls, NULL);
518 env.loop_attr_set = new_set(loop_attr_cmp, 5);
519 env.block_attr_set = new_set(block_attr_cmp, 20);
521 /*-- Part1: Analysis --*/
522 be_liveness_recompute(chordal_env->lv);
524 /* construct control flow loop tree */
525 construct_cf_backedges(chordal_env->irg);
527 /* construct loop out edges and livethrough_unused sets for loops and blocks */
528 irg_block_walk_graph(chordal_env->irg, construct_block_livethrough_unused, construct_loop_edges, &env);
529 construct_loop_livethrough_unused(&env, get_irg_loop(env.irg));
531 /*-- Part2: Transformation --*/
533 /* spill unused livethrough values around loops and blocks where
534 * the pressure is too high
536 reduce_register_pressure_in_loop(&env, get_irg_loop(env.irg), 0);
538 /* Insert real spill/reload nodes and fix usages */
539 be_insert_spills_reloads(env.senv);
541 /* Verify the result */
542 if (chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN) {
543 be_verify_schedule(env.irg);
544 } else if (chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT) {
545 assert(be_verify_schedule(env.irg));
548 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPILL)
549 be_dump(env.irg, "-spillmorgan", dump_ir_block_graph_sched);
552 free_loop_edges(&env);
553 del_set(env.loop_attr_set);
554 del_set(env.block_attr_set);
556 /* fix the remaining places with too high register pressure with beladies algorithm */
557 be_spill_belady_spill_env(chordal_env, env.senv);
559 be_delete_spill_env(env.senv);
560 obstack_free(&env.obst, NULL);