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
28 #include "bessadestr.h"
35 #include "iredges_t.h"
43 #include "bechordal_t.h"
48 #include "bestatevent.h"
50 #include "beintlive_t.h"
52 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
54 static void clear_link(ir_node *irn, void *data)
57 set_irn_link(irn, NULL);
61 * For each block build a linked list of phis that
63 * - have the current register class
64 * The list is rooted at get_irn_link(BB).
66 static void collect_phis_walker(ir_node *irn, void *data)
68 be_chordal_env_t *env = (be_chordal_env_t*)data;
69 if (is_Phi(irn) && chordal_has_class(env, irn)) {
70 ir_node *bl = get_nodes_block(irn);
71 set_irn_link(irn, get_irn_link(bl));
72 set_irn_link(bl, irn);
77 * This struct represents a Proj for a Perm.
78 * It records the argument in the Perm and the corresponding Proj of the
82 ir_node *arg; /**< The phi argument to make the Proj for. */
83 int pos; /**< The proj number the Proj will get.
84 This also denotes the position of @p arg
85 in the in array of the Perm. */
86 ir_node *proj; /**< The proj created for @p arg. */
89 static int cmp_perm_proj(const void *a, const void *b, size_t n)
91 const perm_proj_t *p = (const perm_proj_t*)a;
92 const perm_proj_t *q = (const perm_proj_t*)b;
95 return !(p->arg == q->arg);
98 typedef struct insert_all_perms_env_t {
99 be_chordal_env_t *chordal_env;
101 } insert_all_perms_env_t;
104 * Insert Perms in all predecessors of a block containing a phi
106 static void insert_all_perms_walker(ir_node *bl, void *data)
108 insert_all_perms_env_t *env = (insert_all_perms_env_t*)data;
109 be_chordal_env_t *chordal_env = env->chordal_env;
110 pmap *perm_map = env->perm_map;
111 be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
114 assert(is_Block(bl));
116 /* If the link flag is NULL, this block has no phis. */
117 if (!get_irn_link(bl))
120 /* Look at all predecessors of the phi block */
121 for (i = 0, n = get_irn_arity(bl); i < n; ++i) {
122 ir_node *phi, *perm, *insert_after, **in;
124 set *arg_set = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
125 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
128 assert(!pmap_contains(perm_map, pred_bl) && "Already permed that block");
131 * Note that all phis in the list are in the same
132 * register class by construction.
134 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
135 phi = (ir_node*)get_irn_link(phi)) {
136 ir_node *arg = get_irn_n(phi, i);
140 hash = hash_irn(arg);
142 pp = (perm_proj_t*)set_find(arg_set, &templ, sizeof(templ), hash);
145 * If a proj_perm_t entry has not been made in the argument set,
146 * create one. The only restriction is, that the phi argument
147 * may not be live in at the current block, since this argument
148 * interferes with the phi and must thus not be member of a
149 * Perm. A copy will be inserted for this argument later on.
151 if (!pp && !be_is_live_in(lv, bl, arg)) {
152 templ.pos = n_projs++;
153 set_insert(arg_set, &templ, sizeof(templ), hash);
160 * Create a new Perm with the arguments just collected
161 * above in the arg_set and insert it into the schedule.
163 in = XMALLOCN(ir_node*, n_projs);
164 foreach_set(arg_set, perm_proj_t*, pp) {
165 in[pp->pos] = pp->arg;
168 perm = be_new_Perm(chordal_env->cls, pred_bl, n_projs, in);
169 be_stat_ev("phi_perm", n_projs);
171 insert_after = pred_bl;
173 insert_after = sched_prev(insert_after);
174 } while (is_cfop(insert_after));
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 foreach_set(arg_set, perm_proj_t*, pp) {
184 ir_node *proj = new_r_Proj(perm, get_irn_mode(pp->arg), pp->pos);
186 assert(arch_get_irn_register(pp->arg));
187 arch_set_irn_register(proj, arch_get_irn_register(pp->arg));
189 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", arch_get_irn_register(pp->arg)->name, pp->arg, pp->proj));
193 * Set the phi nodes to their new arguments: The Projs of the Perm
195 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
196 phi = (ir_node*)get_irn_link(phi)) {
199 templ.arg = get_irn_n(phi, i);
200 pp = (perm_proj_t*)set_find(arg_set, &templ, sizeof(templ), hash_irn(templ.arg));
202 /* If not found, it was an interfering argument */
204 set_irn_n(phi, i, pp->proj);
205 be_liveness_introduce(lv, pp->proj);
209 /* update the liveness of the Perm's operands. It might be changed. */
212 for (i = 0; i < n_projs; ++i)
213 be_liveness_update(lv, in[i]);
217 /* register in perm map */
218 pmap_insert(perm_map, pred_bl, perm);
225 #define is_pinned(irn) (get_irn_link(irn))
226 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
227 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
230 * Adjusts the register allocation for the (new) phi-operands
231 * and insert duplicates iff necessary.
233 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data)
235 be_chordal_env_t *chordal_env = (be_chordal_env_t*)data;
236 be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
239 /* Consider all phis of this block */
240 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
241 phi = (ir_node*)get_irn_link(phi)) {
242 ir_node *phi_block = get_nodes_block(phi);
243 const arch_register_t *phi_reg = arch_get_irn_register(phi);
247 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
249 /* process all arguments of the phi */
250 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
251 ir_node *arg = get_irn_n(phi, i);
252 const arch_register_t *arg_reg;
255 arg_block = get_Block_cfgpred_block(phi_block, i);
256 arg_reg = arch_get_irn_register(arg);
258 assert(arg_reg && "Register must be set while placing perms");
260 DBG((dbg, LEVEL_1, " for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
262 if (phi_reg == arg_reg
263 || (arg_reg->type & arch_register_type_joker)
264 || (arg_reg->type & arch_register_type_virtual)) {
265 /* Phi and arg have the same register, so pin and continue */
266 pin_irn(arg, phi_block);
267 DBG((dbg, LEVEL_1, " arg has same reg: pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
271 if (be_values_interfere(lv, phi, arg)) {
275 Insert a duplicate in arguments block,
276 make it the new phi arg,
278 insert it into schedule,
281 ir_node *dupl = be_new_Copy(arg_block, arg);
283 set_irn_n(phi, i, dupl);
284 arch_set_irn_register(dupl, phi_reg);
285 schedpoint = arg_block;
287 schedpoint = sched_prev(schedpoint);
288 } while (is_cfop(schedpoint));
289 sched_add_after(schedpoint, dupl);
290 pin_irn(dupl, phi_block);
291 be_liveness_introduce(lv, dupl);
292 be_liveness_update(lv, arg);
293 DBG((dbg, LEVEL_1, " they do interfere: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
294 continue; /* with next argument */
297 DBG((dbg, LEVEL_1, " they do not interfere\n"));
298 assert(is_Proj(arg));
300 First check if there is an other phi
302 - having arg at the current pos in its arg-list
303 - having the same color as arg
305 If found, then pin the arg (for that phi)
307 if (! is_pinned(arg)) {
310 DBG((dbg, LEVEL_1, " searching for phi with same arg having args register\n"));
312 for (other_phi = (ir_node*)get_irn_link(phi_block);
314 other_phi = (ir_node*)get_irn_link(other_phi)) {
316 assert(is_Phi(other_phi) &&
317 get_nodes_block(phi) == get_nodes_block(other_phi) &&
318 "link fields are screwed up");
320 if (get_irn_n(other_phi, i) == arg && arch_get_irn_register(other_phi) == arg_reg) {
321 DBG((dbg, LEVEL_1, " found %+F(%s)\n", other_phi, arch_get_irn_register(other_phi)->name));
322 pin_irn(arg, phi_block);
328 if (is_pinned(arg)) {
330 Insert a duplicate of the original value in arguments block,
331 make it the new phi arg,
333 insert it into schedule,
336 ir_node *perm = get_Proj_pred(arg);
337 ir_node *dupl = be_new_Copy(arg_block, arg);
340 set_irn_n(phi, i, dupl);
341 arch_set_irn_register(dupl, phi_reg);
342 /* skip the Perm's Projs and insert the copies behind. */
343 for (ins = sched_next(perm); is_Proj(ins); ins = sched_next(ins)) {
345 sched_add_before(ins, dupl);
346 pin_irn(dupl, phi_block);
347 be_liveness_introduce(lv, dupl);
348 be_liveness_update(lv, arg);
349 DBG((dbg, LEVEL_1, " arg is pinned: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
352 No other phi has the same color (else arg would have been pinned),
353 so just set the register and pin
355 arch_set_irn_register(arg, phi_reg);
356 pin_irn(arg, phi_block);
357 DBG((dbg, LEVEL_1, " arg is not pinned: so pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
363 void be_ssa_destruction(be_chordal_env_t *chordal_env)
365 insert_all_perms_env_t insert_perms_env;
366 pmap *perm_map = pmap_create();
367 ir_graph *irg = chordal_env->irg;
369 FIRM_DBG_REGISTER(dbg, "ir.be.ssadestr");
371 be_invalidate_live_sets(irg);
373 /* create a map for fast lookup of perms: block --> perm */
374 irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
376 DBG((dbg, LEVEL_1, "Placing perms...\n"));
377 insert_perms_env.chordal_env = chordal_env;
378 insert_perms_env.perm_map = perm_map;
379 irg_block_walk_graph(irg, insert_all_perms_walker, NULL, &insert_perms_env);
381 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
382 dump_ir_graph(irg, "ssa_destr_perms_placed");
384 be_assure_live_chk(irg);
386 DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
387 irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
389 /* unfortunately updating doesn't work yet. */
390 be_invalidate_live_chk(irg);
392 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
393 dump_ir_graph(irg, "ssa_destr_regs_set");
395 pmap_destroy(perm_map);
398 static void ssa_destruction_check_walker(ir_node *bl, void *data)
404 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
405 phi = (ir_node*)get_irn_link(phi)) {
406 const arch_register_t *phi_reg, *arg_reg;
408 phi_reg = arch_get_irn_register(phi);
409 /* iterate over all args of phi */
410 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
411 ir_node *arg = get_irn_n(phi, i);
412 const arch_register_req_t *req = arch_get_irn_register_req(arg);
414 if (req->type & arch_register_req_type_ignore)
417 arg_reg = arch_get_irn_register(arg);
419 if (phi_reg != arg_reg) {
420 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
424 if (! is_pinned(arg)) {
425 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
432 void be_ssa_destruction_check(be_chordal_env_t *chordal_env)
434 irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, NULL);