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"
50 #include "beintlive_t.h"
51 #include "bespillutil.h"
53 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
55 static void clear_link(ir_node *irn, void *data)
58 set_irn_link(irn, NULL);
62 * For each block build a linked list of phis that
64 * - have the current register class
65 * The list is rooted at get_irn_link(BB).
67 static void collect_phis_walker(ir_node *irn, void *data)
69 be_chordal_env_t *env = (be_chordal_env_t*)data;
70 if (is_Phi(irn) && arch_irn_consider_in_reg_alloc(env->cls, irn)) {
71 ir_node *bl = get_nodes_block(irn);
72 set_irn_link(irn, get_irn_link(bl));
73 set_irn_link(bl, irn);
78 * This struct represents a Proj for a Perm.
79 * It records the argument in the Perm and the corresponding Proj of the
83 ir_node *arg; /**< The phi argument to make the Proj for. */
84 int pos; /**< The proj number the Proj will get.
85 This also denotes the position of @p arg
86 in the in array of the Perm. */
87 ir_node *proj; /**< The proj created for @p arg. */
90 static int cmp_perm_proj(const void *a, const void *b, size_t n)
92 const perm_proj_t *p = (const perm_proj_t*)a;
93 const perm_proj_t *q = (const perm_proj_t*)b;
96 return !(p->arg == q->arg);
100 * Insert Perms in all predecessors of a block containing a phi
102 static void insert_all_perms_walker(ir_node *bl, void *data)
104 be_chordal_env_t *const chordal_env = (be_chordal_env_t*)data;
105 be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
108 assert(is_Block(bl));
110 /* If the link flag is NULL, this block has no phis. */
111 if (!get_irn_link(bl))
114 /* Look at all predecessors of the phi block */
115 for (i = 0, n = get_irn_arity(bl); i < n; ++i) {
116 ir_node *phi, *perm, **in;
117 set *arg_set = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
118 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
122 * Note that all phis in the list are in the same
123 * register class by construction.
125 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
126 phi = (ir_node*)get_irn_link(phi)) {
127 ir_node *arg = get_irn_n(phi, i);
131 hash = hash_irn(arg);
133 perm_proj_t *const pp = set_find(perm_proj_t, arg_set, &templ, sizeof(templ), hash);
136 * If a proj_perm_t entry has not been made in the argument set,
137 * create one. The only restriction is, that the phi argument
138 * may not be live in at the current block, since this argument
139 * interferes with the phi and must thus not be member of a
140 * Perm. A copy will be inserted for this argument later on.
142 if (!pp && !be_is_live_in(lv, bl, arg)) {
143 templ.pos = n_projs++;
144 (void)set_insert(perm_proj_t, arg_set, &templ, sizeof(templ), hash);
151 * Create a new Perm with the arguments just collected
152 * above in the arg_set and insert it into the schedule.
154 in = XMALLOCN(ir_node*, n_projs);
155 foreach_set(arg_set, perm_proj_t, pp) {
156 in[pp->pos] = pp->arg;
159 perm = be_new_Perm(chordal_env->cls, pred_bl, n_projs, in);
160 stat_ev_int("phi_perm", n_projs);
162 ir_node *const schedpoint = be_get_end_of_block_insertion_point(pred_bl);
163 sched_add_before(schedpoint, perm);
166 * Make the Projs for the Perm and insert into schedule.
167 * Register allocation is copied from the former phi
168 * arguments to the projs (new phi arguments).
170 foreach_set(arg_set, perm_proj_t, pp) {
171 ir_node *proj = new_r_Proj(perm, get_irn_mode(pp->arg), pp->pos);
173 assert(arch_get_irn_register(pp->arg));
174 arch_set_irn_register(proj, arch_get_irn_register(pp->arg));
175 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", arch_get_irn_register(pp->arg)->name, pp->arg, pp->proj));
179 * Set the phi nodes to their new arguments: The Projs of the Perm
181 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
182 phi = (ir_node*)get_irn_link(phi)) {
185 templ.arg = get_irn_n(phi, i);
186 perm_proj_t *const pp = set_find(perm_proj_t, arg_set, &templ, sizeof(templ), hash_irn(templ.arg));
188 /* If not found, it was an interfering argument */
190 set_irn_n(phi, i, pp->proj);
191 be_liveness_introduce(lv, pp->proj);
195 /* update the liveness of the Perm's operands. It might be changed. */
198 for (i = 0; i < n_projs; ++i)
199 be_liveness_update(lv, in[i]);
208 #define is_pinned(irn) (get_irn_link(irn))
209 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
210 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
213 * Adjusts the register allocation for the (new) phi-operands
214 * and insert duplicates iff necessary.
216 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data)
218 be_chordal_env_t *chordal_env = (be_chordal_env_t*)data;
219 be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
222 /* Consider all phis of this block */
223 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
224 phi = (ir_node*)get_irn_link(phi)) {
225 ir_node *phi_block = get_nodes_block(phi);
226 const arch_register_t *phi_reg = arch_get_irn_register(phi);
230 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
232 /* process all arguments of the phi */
233 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
234 ir_node *arg = get_irn_n(phi, i);
235 const arch_register_t *arg_reg;
238 arg_block = get_Block_cfgpred_block(phi_block, i);
239 arg_reg = arch_get_irn_register(arg);
241 assert(arg_reg && "Register must be set while placing perms");
243 DBG((dbg, LEVEL_1, " for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
245 if (phi_reg == arg_reg
246 || (arg_reg->type & arch_register_type_virtual)) {
247 /* Phi and arg have the same register, so pin and continue */
248 pin_irn(arg, phi_block);
249 DBG((dbg, LEVEL_1, " arg has same reg: pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
253 if (be_values_interfere(lv, phi, arg)) {
255 Insert a duplicate in arguments block,
256 make it the new phi arg,
258 insert it into schedule,
261 ir_node *dupl = be_new_Copy(arg_block, arg);
263 set_irn_n(phi, i, dupl);
264 arch_set_irn_register(dupl, phi_reg);
265 ir_node *const schedpoint = be_get_end_of_block_insertion_point(arg_block);
266 sched_add_before(schedpoint, dupl);
267 pin_irn(dupl, phi_block);
268 be_liveness_introduce(lv, dupl);
269 be_liveness_update(lv, arg);
270 DBG((dbg, LEVEL_1, " they do interfere: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
271 continue; /* with next argument */
274 DBG((dbg, LEVEL_1, " they do not interfere\n"));
275 assert(is_Proj(arg));
277 First check if there is an other phi
279 - having arg at the current pos in its arg-list
280 - having the same color as arg
282 If found, then pin the arg (for that phi)
284 if (! is_pinned(arg)) {
287 DBG((dbg, LEVEL_1, " searching for phi with same arg having args register\n"));
289 for (other_phi = (ir_node*)get_irn_link(phi_block);
291 other_phi = (ir_node*)get_irn_link(other_phi)) {
293 assert(is_Phi(other_phi) &&
294 get_nodes_block(phi) == get_nodes_block(other_phi) &&
295 "link fields are screwed up");
297 if (get_irn_n(other_phi, i) == arg && arch_get_irn_register(other_phi) == arg_reg) {
298 DBG((dbg, LEVEL_1, " found %+F(%s)\n", other_phi, arch_get_irn_register(other_phi)->name));
299 pin_irn(arg, phi_block);
305 if (is_pinned(arg)) {
307 Insert a duplicate of the original value in arguments block,
308 make it the new phi arg,
310 insert it into schedule,
313 ir_node *perm = get_Proj_pred(arg);
314 ir_node *dupl = be_new_Copy(arg_block, arg);
316 set_irn_n(phi, i, dupl);
317 arch_set_irn_register(dupl, phi_reg);
318 sched_add_after(perm, dupl);
319 pin_irn(dupl, phi_block);
320 be_liveness_introduce(lv, dupl);
321 be_liveness_update(lv, arg);
322 DBG((dbg, LEVEL_1, " arg is pinned: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
325 No other phi has the same color (else arg would have been pinned),
326 so just set the register and pin
328 arch_set_irn_register(arg, phi_reg);
329 pin_irn(arg, phi_block);
330 DBG((dbg, LEVEL_1, " arg is not pinned: so pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
336 void be_ssa_destruction(be_chordal_env_t *chordal_env)
338 ir_graph *irg = chordal_env->irg;
340 FIRM_DBG_REGISTER(dbg, "ir.be.ssadestr");
342 be_invalidate_live_sets(irg);
344 /* create a map for fast lookup of perms: block --> perm */
345 irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
347 DBG((dbg, LEVEL_1, "Placing perms...\n"));
348 irg_block_walk_graph(irg, insert_all_perms_walker, NULL, chordal_env);
350 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
351 dump_ir_graph(irg, "ssa_destr_perms_placed");
353 be_assure_live_chk(irg);
355 DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
356 irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
358 /* unfortunately updating doesn't work yet. */
359 be_invalidate_live_chk(irg);
361 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
362 dump_ir_graph(irg, "ssa_destr_regs_set");
365 static void ssa_destruction_check_walker(ir_node *bl, void *data)
371 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
372 phi = (ir_node*)get_irn_link(phi)) {
373 const arch_register_t *phi_reg, *arg_reg;
375 phi_reg = arch_get_irn_register(phi);
376 /* iterate over all args of phi */
377 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
378 ir_node *arg = get_irn_n(phi, i);
379 const arch_register_req_t *req = arch_get_irn_register_req(arg);
380 if (arch_register_req_is(req, ignore))
383 arg_reg = arch_get_irn_register(arg);
385 if (phi_reg != arg_reg) {
386 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
390 if (! is_pinned(arg)) {
391 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
398 void be_ssa_destruction_check(be_chordal_env_t *chordal_env)
400 irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, NULL);