4 * Copyright: (c) Universitaet Karlsruhe
5 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
7 * Performs SSA-Destruction.
18 #include "iredges_t.h"
26 #include "bechordal_t.h"
30 #include "besched_t.h"
32 static firm_dbg_module_t *dbg = NULL;
35 #define get_chordal_arch(ce) ((ce)->birg->main_env->arch_env)
36 #define get_reg(irn) arch_get_irn_register(get_chordal_arch(chordal_env), irn)
37 #define set_reg(irn, reg) arch_set_irn_register(get_chordal_arch(chordal_env), irn, reg)
39 #define is_Perm(irn) (arch_irn_classify(arch_env, irn) == arch_irn_class_perm)
40 #define get_reg_cls(irn) (arch_get_irn_reg_class(arch_env, irn, -1))
41 #define is_curr_reg_class(irn) (get_reg_cls(p) == chordal_env->cls)
43 static void clear_link(ir_node *irn, void *data) {
44 set_irn_link(irn, NULL);
48 * For each block build a linked list of phis that
50 * - have the current register class
51 * The list is rooted at get_irn_link(BB).
53 static void collect_phis_walker(ir_node *irn, void *data) {
54 be_chordal_env_t *env = data;
55 if(is_Phi(irn) && chordal_has_class(env, irn)) {
56 ir_node *bl = get_nodes_block(irn);
57 set_irn_link(irn, get_irn_link(bl));
58 set_irn_link(bl, irn);
63 * This struct represents a Proj for a Perm.
64 * It records the argument in the Perm and the corresponding Proj of the
68 ir_node *arg; /**< The phi argument to make the Proj for. */
69 int pos; /**< The proj number the Proj will get.
70 This also denotes the position of @p arg
71 in the in array of the Perm. */
72 ir_node *proj; /**< The proj created for @p arg. */
75 static int cmp_perm_proj(const void *a, const void *b, size_t n) {
76 const perm_proj_t *p = a;
77 const perm_proj_t *q = b;
78 return !(p->arg == q->arg);
82 * Insert Perms in all predecessors of a block containing a phi
84 static void insert_all_perms_walker(ir_node *bl, void *data) {
85 be_chordal_env_t *chordal_env = data;
86 pmap *perm_map = chordal_env->data;
87 ir_graph *irg = chordal_env->irg;
92 /* If the link flag is NULL, this block has no phis. */
96 /* Look at all predecessors of the phi block */
97 for(i = 0, n = get_irn_arity(bl); i < n; ++i) {
98 ir_node *phi, *perm, *insert_after, **in;
100 set *arg_set = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
101 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
104 assert(!pmap_contains(perm_map, pred_bl) && "Already permed that block");
107 * Note that all phis in the list are in the same
108 * register class by construction.
110 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
112 ir_node *arg = get_irn_n(phi, i);
113 unsigned hash = HASH_PTR(arg);
116 pp = set_find(arg_set, &templ, sizeof(templ), hash);
119 * If a proj_perm_t entry has not been made in the argument set,
120 * create one. The only restriction is, that the phi argument
121 * may not be live in at the current block, since this argument
122 * interferes with the phi and must thus not be member of a
123 * Perm. A copy will be inserted for this argument alter on.
125 if(!pp && !is_live_in(bl, arg)) {
126 templ.pos = n_projs++;
127 set_insert(arg_set, &templ, sizeof(templ), hash);
134 * Create a new Perm with the arguments just collected
135 * above in the arg_set and insert it into the schedule.
137 in = malloc(n_projs * sizeof(in[0]));
138 for(pp = set_first(arg_set); pp; pp = set_next(arg_set))
139 in[pp->pos] = pp->arg;
141 perm = be_new_Perm(chordal_env->cls, irg, pred_bl, n_projs, in);
143 insert_after = sched_skip(sched_last(pred_bl), 0, sched_skip_cf_predicator, chordal_env->birg->main_env->arch_env);
144 sched_add_after(insert_after, perm);
147 * Make the Projs for the Perm and insert into schedule.
148 * Register allocation is copied from the former phi
149 * arguments to the projs (new phi arguments).
152 for(pp = set_first(arg_set); pp; pp = set_next(arg_set)) {
153 ir_node *proj = new_r_Proj(irg, pred_bl, perm, get_irn_mode(pp->arg), pp->pos);
155 assert(get_reg(pp->arg));
156 set_reg(proj, get_reg(pp->arg));
157 sched_add_after(insert_after, proj);
159 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", get_reg(pp->arg)->name, pp->arg, pp->proj));
163 * Set the phi nodes to their new arguments: The Projs of the Perm
165 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
168 templ.arg = get_irn_n(phi, i);
169 pp = set_find(arg_set, &templ, sizeof(templ), HASH_PTR(templ.arg));
171 /* If not found, it was an interfering argument */
173 set_irn_n(phi, i, pp->proj);
176 /* register in perm map */
177 pmap_insert(perm_map, pred_bl, perm);
184 #define is_pinned(irn) (get_irn_link(irn))
185 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
186 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
189 * Adjusts the register allocation for the (new) phi-operands
190 * and insert duplicates iff necessary.
192 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data) {
193 be_chordal_env_t *chordal_env = data;
196 /* Consider all phis of this block */
197 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
199 ir_node *arg, *phi_block, *arg_block;
200 const arch_register_t *phi_reg, *arg_reg;
201 const arch_register_class_t *cls;
203 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
205 phi_block = get_nodes_block(phi);
206 phi_reg = get_reg(phi);
207 cls = arch_get_irn_reg_class(get_chordal_arch(chordal_env), phi, -1);
209 /* process all arguments of the phi */
210 for(i=0, max=get_irn_arity(phi); i<max; ++i) {
211 arg = get_irn_n(phi, i);
212 arg_block = get_Block_cfgpred_block(phi_block, i);
213 arg_reg = get_reg(arg);
214 assert(arg_reg && "Register must be set while placing perms");
216 DBG((dbg, LEVEL_1, " for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
218 if(nodes_interfere(chordal_env, phi, arg)) {
219 /* Insert a duplicate in arguments block,
220 * make it the new phi arg,
222 * insert it into schedule,
225 ir_node *dupl = be_new_Copy(cls, chordal_env->irg, arg_block, arg);
226 assert(get_irn_mode(phi) == get_irn_mode(dupl));
227 set_irn_n(phi, i, dupl);
228 set_reg(dupl, phi_reg);
229 sched_add_after(sched_skip(sched_last(arg_block), 0, sched_skip_cf_predicator, chordal_env->birg->main_env->arch_env), dupl);
230 pin_irn(dupl, phi_block);
231 DBG((dbg, LEVEL_1, " they do interfere: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
232 continue; /* with next argument */
235 if (phi_reg == arg_reg) {
236 /* Phi and arg have the same register,
237 * so pin and continue
239 pin_irn(arg, phi_block);
240 DBG((dbg, LEVEL_1, " arg has same reg: pin %+F(%s)\n", arg, get_reg(arg)->name));
244 DBG((dbg, LEVEL_1, " they do not interfere\n"));
245 assert(is_Proj(arg));
247 * First check if there is an other phi
248 * - in the same block
249 * - having arg at the current pos in its arg-list
250 * - having the same color as arg
252 * If found, then pin the arg (for that phi)
254 if (!is_pinned(arg)) {
256 DBG((dbg, LEVEL_1, " searching for phi with same arg having args register\n"));
257 for(other_phi = get_irn_link(phi_block); other_phi; other_phi = get_irn_link(other_phi)) {
258 assert(is_Phi(other_phi) && get_nodes_block(phi) == get_nodes_block(other_phi) && "link fields are screwed up");
259 if (get_irn_n(other_phi, i) == arg && get_reg(other_phi) == arg_reg) {
260 DBG((dbg, LEVEL_1, " found %+F(%s)\n", other_phi, get_reg(other_phi)->name));
261 pin_irn(arg, phi_block);
267 if (is_pinned(arg)) {
268 /* Insert a duplicate of the original value in arguments block,
269 * make it the new phi arg,
271 * insert it into schedule,
274 ir_node *perm = get_Proj_pred(arg);
275 ir_node *orig_val = get_irn_n(perm, get_Proj_proj(arg));
276 ir_node *dupl = be_new_Copy(cls, chordal_env->irg, arg_block, orig_val);
277 assert(get_irn_mode(phi) == get_irn_mode(dupl));
278 set_irn_n(phi, i, dupl);
279 set_reg(dupl, phi_reg);
280 sched_add_before(perm, dupl);
281 pin_irn(dupl, phi_block);
282 DBG((dbg, LEVEL_1, " arg is pinned: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
284 /* No other phi has the same color (else arg would have been pinned),
285 * so just set the register and pin
287 set_reg(arg, phi_reg);
288 pin_irn(arg, phi_block);
289 DBG((dbg, LEVEL_1, " arg is not pinned: so pin %+F(%s)\n", arg, get_reg(arg)->name));
295 void be_ssa_destruction(be_chordal_env_t *chordal_env) {
296 pmap *perm_map = pmap_create();
297 ir_graph *irg = chordal_env->irg;
299 dbg = firm_dbg_register("ir.be.ssadestr");
301 /* create a map for fast lookup of perms: block --> perm */
302 chordal_env->data = perm_map;
303 irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
305 DBG((dbg, LEVEL_1, "Placing perms...\n"));
306 irg_block_walk_graph(irg, insert_all_perms_walker, NULL, chordal_env);
308 dump_ir_block_graph_sched(irg, "-ssa_destr_perms_placed");
311 DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
312 irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
314 dump_ir_block_graph_sched(irg, "-ssa_destr_regs_set");
317 pmap_destroy(perm_map);
320 static void ssa_destruction_check_walker(ir_node *bl, void *data) {
321 be_chordal_env_t *chordal_env = data;
325 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
326 const arch_register_t *phi_reg, *arg_reg;
328 phi_reg = get_reg(phi);
329 /* iterate over all args of phi */
330 for(i=0, max=get_irn_arity(phi); i<max; ++i) {
331 ir_node *arg = get_irn_n(phi, i);
332 arg_reg = get_reg(arg);
333 if(phi_reg != arg_reg) {
334 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
337 if(!is_pinned(arg)) {
338 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
345 void be_ssa_destruction_check(be_chordal_env_t *chordal_env) {
346 irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, chordal_env);