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 Performs SSA-Destruction.
23 * @author Daniel Grund
34 #include "iredges_t.h"
42 #include "bechordal_t.h"
46 #include "besched_t.h"
47 #include "bestatevent.h"
49 #include "beintlive_t.h"
51 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
53 #define get_reg(irn) arch_get_irn_register(irn)
54 #define set_reg(irn, reg) arch_set_irn_register(irn, reg)
56 #define is_Perm(irn) (arch_irn_class_is(arch_env, irn, perm))
57 #define get_reg_cls(irn) (arch_get_irn_reg_class(arch_env, irn, -1))
58 #define is_curr_reg_class(irn) (get_reg_cls(p) == chordal_env->cls)
60 static void clear_link(ir_node *irn, void *data) {
62 set_irn_link(irn, NULL);
66 * For each block build a linked list of phis that
68 * - have the current register class
69 * The list is rooted at get_irn_link(BB).
71 static void collect_phis_walker(ir_node *irn, void *data) {
72 be_chordal_env_t *env = data;
73 if (is_Phi(irn) && chordal_has_class(env, irn)) {
74 ir_node *bl = get_nodes_block(irn);
75 set_irn_link(irn, get_irn_link(bl));
76 set_irn_link(bl, irn);
81 * This struct represents a Proj for a Perm.
82 * It records the argument in the Perm and the corresponding Proj of the
86 ir_node *arg; /**< The phi argument to make the Proj for. */
87 int pos; /**< The proj number the Proj will get.
88 This also denotes the position of @p arg
89 in the in array of the Perm. */
90 ir_node *proj; /**< The proj created for @p arg. */
93 static int cmp_perm_proj(const void *a, const void *b, size_t n) {
94 const perm_proj_t *p = a;
95 const perm_proj_t *q = b;
98 return !(p->arg == q->arg);
101 typedef struct insert_all_perms_env_t {
102 be_chordal_env_t *chordal_env;
104 } insert_all_perms_env_t;
107 * Insert Perms in all predecessors of a block containing a phi
109 static void insert_all_perms_walker(ir_node *bl, void *data) {
110 insert_all_perms_env_t *env = data;
111 be_chordal_env_t *chordal_env = env->chordal_env;
112 pmap *perm_map = env->perm_map;
113 ir_graph *irg = chordal_env->irg;
114 be_lv_t *lv = chordal_env->birg->lv;
117 assert(is_Block(bl));
119 /* If the link flag is NULL, this block has no phis. */
120 if(!get_irn_link(bl))
123 /* Look at all predecessors of the phi block */
124 for(i = 0, n = get_irn_arity(bl); i < n; ++i) {
125 ir_node *phi, *perm, *insert_after, **in;
127 set *arg_set = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
128 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
131 assert(!pmap_contains(perm_map, pred_bl) && "Already permed that block");
134 * Note that all phis in the list are in the same
135 * register class by construction.
137 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
138 ir_node *arg = get_irn_n(phi, i);
139 unsigned hash = hash_irn(arg);
142 if (arch_irn_is(arg, ignore))
146 pp = set_find(arg_set, &templ, sizeof(templ), hash);
149 * If a proj_perm_t entry has not been made in the argument set,
150 * create one. The only restriction is, that the phi argument
151 * may not be live in at the current block, since this argument
152 * interferes with the phi and must thus not be member of a
153 * Perm. A copy will be inserted for this argument alter on.
155 if(!pp && !be_is_live_in(lv, bl, arg)) {
156 templ.pos = n_projs++;
157 set_insert(arg_set, &templ, sizeof(templ), hash);
164 * Create a new Perm with the arguments just collected
165 * above in the arg_set and insert it into the schedule.
167 in = XMALLOCN(ir_node*, n_projs);
168 for(pp = set_first(arg_set); pp; pp = set_next(arg_set))
169 in[pp->pos] = pp->arg;
171 perm = be_new_Perm(chordal_env->cls, irg, pred_bl, n_projs, in);
172 be_stat_ev("phi_perm", n_projs);
174 insert_after = sched_skip(sched_last(pred_bl), 0, sched_skip_cf_predicator, NULL);
175 sched_add_after(insert_after, perm);
178 * Make the Projs for the Perm and insert into schedule.
179 * Register allocation is copied from the former phi
180 * arguments to the projs (new phi arguments).
183 for(pp = set_first(arg_set); pp; pp = set_next(arg_set)) {
184 ir_node *proj = new_r_Proj(irg, pred_bl, perm, get_irn_mode(pp->arg), pp->pos);
186 assert(get_reg(pp->arg));
187 set_reg(proj, get_reg(pp->arg));
189 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", get_reg(pp->arg)->name, pp->arg, pp->proj));
193 * Set the phi nodes to their new arguments: The Projs of the Perm
195 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
198 templ.arg = get_irn_n(phi, i);
199 pp = set_find(arg_set, &templ, sizeof(templ), hash_irn(templ.arg));
201 /* If not found, it was an interfering argument */
203 set_irn_n(phi, i, pp->proj);
204 be_liveness_introduce(lv, pp->proj);
208 /* update the liveness of the Perm's operands. It might be changed. */
211 for (i = 0; i < n_projs; ++i)
212 be_liveness_update(lv, in[i]);
216 /* register in perm map */
217 pmap_insert(perm_map, pred_bl, perm);
224 #define is_pinned(irn) (get_irn_link(irn))
225 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
226 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
229 * Adjusts the register allocation for the (new) phi-operands
230 * and insert duplicates iff necessary.
232 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data) {
233 be_chordal_env_t *chordal_env = data;
234 be_lv_t *lv = chordal_env->birg->lv;
237 /* Consider all phis of this block */
238 for (phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
240 ir_node *arg, *phi_block, *arg_block;
241 const arch_register_t *phi_reg, *arg_reg;
242 const arch_register_class_t *cls;
244 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
246 phi_block = get_nodes_block(phi);
247 phi_reg = get_reg(phi);
248 cls = arch_get_irn_reg_class(phi, -1);
250 /* process all arguments of the phi */
251 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
252 arg = get_irn_n(phi, i);
253 arg_block = get_Block_cfgpred_block(phi_block, i);
254 arg_reg = get_reg(arg);
256 if (arch_irn_is(arg, ignore))
259 assert(arg_reg && "Register must be set while placing perms");
261 DBG((dbg, LEVEL_1, " for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
263 if (values_interfere(chordal_env->birg, phi, arg)) {
265 Insert a duplicate in arguments block,
266 make it the new phi arg,
268 insert it into schedule,
271 ir_node *dupl = be_new_Copy(cls, chordal_env->irg, arg_block, arg);
273 /* this is commented out because it will fail in case of unknown float */
275 ir_mode *m_phi = get_irn_mode(phi), *m_dupl = get_irn_mode(dupl);
278 Conv signed <-> unsigned is killed on ia32
279 check for: (both int OR both float) AND equal mode sizes
281 assert(((mode_is_int(m_phi) && mode_is_int(m_dupl)) ||
282 (mode_is_float(m_phi) && mode_is_float(m_dupl))) &&
283 (get_mode_size_bits(m_phi) == get_mode_size_bits(m_dupl)));
286 set_irn_n(phi, i, dupl);
287 set_reg(dupl, phi_reg);
288 sched_add_after(sched_skip(sched_last(arg_block), 0, sched_skip_cf_predicator, NULL), dupl);
289 pin_irn(dupl, phi_block);
290 be_liveness_introduce(lv, dupl);
291 be_liveness_update(lv, arg);
292 DBG((dbg, LEVEL_1, " they do interfere: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
293 continue; /* with next argument */
296 if (phi_reg == arg_reg) {
297 /* Phi and arg have the same register, so pin and continue */
298 pin_irn(arg, phi_block);
299 DBG((dbg, LEVEL_1, " arg has same reg: pin %+F(%s)\n", arg, get_reg(arg)->name));
303 DBG((dbg, LEVEL_1, " they do not interfere\n"));
304 assert(is_Proj(arg));
306 First check if there is an other phi
308 - having arg at the current pos in its arg-list
309 - having the same color as arg
311 If found, then pin the arg (for that phi)
313 if (! is_pinned(arg)) {
316 DBG((dbg, LEVEL_1, " searching for phi with same arg having args register\n"));
318 for(other_phi = get_irn_link(phi_block); other_phi; other_phi = get_irn_link(other_phi)) {
320 assert(is_Phi(other_phi) &&
321 get_nodes_block(phi) == get_nodes_block(other_phi) &&
322 "link fields are screwed up");
324 if (get_irn_n(other_phi, i) == arg && get_reg(other_phi) == arg_reg) {
325 DBG((dbg, LEVEL_1, " found %+F(%s)\n", other_phi, get_reg(other_phi)->name));
326 pin_irn(arg, phi_block);
332 if (is_pinned(arg)) {
334 Insert a duplicate of the original value in arguments block,
335 make it the new phi arg,
337 insert it into schedule,
340 ir_node *perm = get_Proj_pred(arg);
341 ir_node *dupl = be_new_Copy(cls, chordal_env->irg, arg_block, arg);
344 /* this is commented out because it will fail in case of unknown float */
346 ir_mode *m_phi = get_irn_mode(phi);
347 ir_mode *m_dupl = get_irn_mode(dupl);
350 Conv signed <-> unsigned is killed on ia32
351 check for: (both int OR both float) AND equal mode sizes
353 assert(((mode_is_int(m_phi) && mode_is_int(m_dupl)) ||
354 (mode_is_float(m_phi) && mode_is_float(m_dupl))) &&
355 (get_mode_size_bits(m_phi) == get_mode_size_bits(m_dupl)));
358 set_irn_n(phi, i, dupl);
359 set_reg(dupl, phi_reg);
360 /* skip the Perm's Projs and insert the copies behind. */
361 for(ins = sched_next(perm); is_Proj(ins); ins = sched_next(ins));
362 sched_add_before(ins, dupl);
363 pin_irn(dupl, phi_block);
364 be_liveness_introduce(lv, dupl);
365 be_liveness_update(lv, arg);
366 DBG((dbg, LEVEL_1, " arg is pinned: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
369 No other phi has the same color (else arg would have been pinned),
370 so just set the register and pin
372 set_reg(arg, phi_reg);
373 pin_irn(arg, phi_block);
374 DBG((dbg, LEVEL_1, " arg is not pinned: so pin %+F(%s)\n", arg, get_reg(arg)->name));
380 void be_ssa_destruction(be_chordal_env_t *chordal_env) {
381 insert_all_perms_env_t insert_perms_env;
382 pmap *perm_map = pmap_create();
383 ir_graph *irg = chordal_env->irg;
384 be_lv_t *lv = be_assure_liveness(chordal_env->birg);
386 FIRM_DBG_REGISTER(dbg, "ir.be.ssadestr");
388 be_liveness_invalidate(lv);
390 /* create a map for fast lookup of perms: block --> perm */
391 irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
393 DBG((dbg, LEVEL_1, "Placing perms...\n"));
394 insert_perms_env.chordal_env = chordal_env;
395 insert_perms_env.perm_map = perm_map;
396 irg_block_walk_graph(irg, insert_all_perms_walker, NULL, &insert_perms_env);
398 // Matze: really needed here?
399 // Sebastian: Yes. the walker function uses interference.
400 be_liveness_invalidate(lv);
402 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
403 be_dump(irg, "-ssa_destr_perms_placed", dump_ir_block_graph_sched);
405 be_liveness_assure_chk(lv);
407 DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
408 irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
410 /* TODO: unfortunaltely updating doesn't work yet. */
411 be_liveness_invalidate(lv);
413 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
414 be_dump(irg, "-ssa_destr_regs_set", dump_ir_block_graph_sched);
416 pmap_destroy(perm_map);
419 static void ssa_destruction_check_walker(ir_node *bl, void *data) {
424 for (phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
425 const arch_register_t *phi_reg, *arg_reg;
427 phi_reg = get_reg(phi);
428 /* iterate over all args of phi */
429 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
430 ir_node *arg = get_irn_n(phi, i);
432 if (arch_irn_is(arg, ignore))
435 arg_reg = get_reg(arg);
437 if (phi_reg != arg_reg) {
438 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
442 if (! is_pinned(arg)) {
443 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
450 void be_ssa_destruction_check(be_chordal_env_t *chordal_env) {
451 irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, NULL);