2 * Copyright (C) 1995-2011 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 Perform optimizations of the type representation.
24 * @author Goetz Lindenmaier
30 #include "iroptimize.h"
32 #include "irtypeinfo.h"
42 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
44 /* - statistics ---------------------------------------------- */
46 static size_t n_casts_normalized = 0;
47 static size_t n_casts_removed = 0;
48 static size_t n_sels_concretized = 0;
50 /* - Cast normalization. ------------------------------------- */
52 static ir_type *default_gen_pointer_type_to(ir_type *tp);
54 #define PTR_TYPE_SUFFIX "cc_ptr_tp" /* class cast pointer type. */
55 static ident *ptr_type_suffix = NULL;
56 static gen_pointer_type_to_func gen_pointer_type_to = default_gen_pointer_type_to;
59 * Find a pointer type to a given type.
60 * Uses and updates trouts if available.
62 static ir_type *default_gen_pointer_type_to(ir_type *tp)
64 ir_type *res = find_pointer_type_to_type(tp);
65 if (is_unknown_type(res))
66 res = new_type_pointer(tp);
71 /** Return a type that is a depth times pointer to type. */
72 static ir_type *pointerize_type(ir_type *tp, size_t depth)
74 for (; depth > 0; --depth) {
75 tp = gen_pointer_type_to(tp);
81 static ir_node *normalize_values_type(ir_type *totype, ir_node *pred)
83 ir_type *fromtype = get_irn_typeinfo_type(pred);
84 ir_node *new_cast = pred;
88 if (totype == fromtype) return pred; /* Case for optimization! */
90 while (is_Pointer_type(totype) && is_Pointer_type(fromtype)) {
91 totype = get_pointer_points_to_type(totype);
92 fromtype = get_pointer_points_to_type(fromtype);
96 if (!is_Class_type(totype)) return pred;
97 if (!is_Class_type(fromtype)) return pred;
99 if ((get_class_supertype_index(totype, fromtype) != (size_t)-1) ||
100 (get_class_supertype_index(fromtype, totype) != (size_t)-1) ) {
101 /* It's just what we want ... */
105 block = get_nodes_block(pred);
107 if (is_SubClass_of(totype, fromtype)) {
109 while (get_class_subtype_index(fromtype, totype) == (size_t)-1) {
110 /* Insert a cast to a subtype of fromtype. */
111 ir_type *new_type = NULL;
114 size_t n_subtypes = get_class_n_subtypes(fromtype);
115 for (i = 0; i < n_subtypes && !new_type; ++i) {
116 ir_type *new_sub = get_class_subtype(fromtype, i);
117 if (is_SuperClass_of(new_sub, totype))
122 new_type = pointerize_type(new_type, ref_depth);
123 new_cast = new_r_Cast(block, pred, new_type);
125 ++n_casts_normalized;
126 set_irn_typeinfo_type(new_cast, new_type); /* keep type information up to date. */
129 assert(is_SuperClass_of(totype, fromtype));
131 while (get_class_supertype_index(fromtype, totype) == (size_t)-1) {
132 /* Insert a cast to a supertype of fromtype. */
133 ir_type *new_type = NULL;
134 size_t i, n_supertypes = get_class_n_supertypes(fromtype);
135 for (i = 0; i < n_supertypes && !new_type; ++i) {
136 ir_type *new_super = get_class_supertype(fromtype, i);
137 if (is_SubClass_of(new_super, totype))
138 new_type = new_super;
142 new_type = pointerize_type(new_type, ref_depth);
143 new_cast = new_r_Cast(block, pred, new_type);
145 ++n_casts_normalized;
146 set_irn_typeinfo_type(new_cast, new_type); /* keep type information up to date. */
155 static void normalize_irn_class_cast(ir_node *n, void *env)
160 ir_node *pred = get_Cast_op(n);
161 ir_type *totype = get_Cast_type(n);
162 res = normalize_values_type(totype, pred);
164 } else if (is_Call(n)) {
165 size_t n_params = get_Call_n_params(n);
167 ir_type *tp = get_Call_type(n);
168 for (i = 0; i < n_params; ++i) {
169 res = normalize_values_type(get_method_param_type(tp, i), get_Call_param(n, i));
170 set_Call_param(n, i, res);
176 static void pure_normalize_irg_class_casts(ir_graph *irg)
178 assert(get_irg_class_cast_state(irg) != ir_class_casts_any &&
179 "Cannot normalize irregular casts.");
180 if (get_irg_class_cast_state(irg) == ir_class_casts_normalized) {
184 irg_walk_graph(irg, NULL, normalize_irn_class_cast, NULL);
185 set_irg_class_cast_state(irg, ir_class_casts_normalized);
189 void normalize_irg_class_casts(ir_graph *irg, gen_pointer_type_to_func gppt_fct)
191 assert(get_irp_typeinfo_state() == ir_typeinfo_consistent);
193 if (gppt_fct) gen_pointer_type_to = gppt_fct;
195 if (!ptr_type_suffix)
196 ptr_type_suffix = new_id_from_str(PTR_TYPE_SUFFIX);
198 pure_normalize_irg_class_casts(irg);
200 gen_pointer_type_to = default_gen_pointer_type_to;
203 void normalize_irp_class_casts(gen_pointer_type_to_func gppt_fct)
206 if (gppt_fct) gen_pointer_type_to = gppt_fct;
209 if (get_irp_typeinfo_state() != ir_typeinfo_consistent)
210 simple_analyse_types();
213 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
214 ir_graph *irg = get_irp_irg(i);
215 pure_normalize_irg_class_casts(irg);
218 set_irp_class_cast_state(ir_class_casts_normalized);
219 gen_pointer_type_to = default_gen_pointer_type_to;
221 DB((dbg, SET_LEVEL_1, " Cast normalization: %zu Casts inserted.\n", n_casts_normalized));
226 /* - Cast optimization. ------------------------------------------- */
231 * (T1)(T2)x<T1> -> x<T1>
233 * (T3)(T2)x<T1> -> (T3)x<T1>
237 * @param cast the Cast node
239 * @return 1 if the cast was changed
241 static int cancel_out_casts(ir_node *cast)
243 ir_node *orig, *pred = get_Cast_op(cast);
244 ir_type *tp_cast, *tp_pred, *tp_orig;
246 if (!is_Cast(pred)) return 0;
247 orig = get_Cast_op(pred);
249 tp_cast = get_Cast_type(cast);
250 tp_pred = get_Cast_type(pred);
251 tp_orig = get_irn_typeinfo_type(orig);
253 while (is_Pointer_type(tp_cast) &&
254 is_Pointer_type(tp_pred) &&
255 is_Pointer_type(tp_orig) ) {
256 tp_cast = get_pointer_points_to_type(tp_cast);
257 tp_pred = get_pointer_points_to_type(tp_pred);
258 tp_orig = get_pointer_points_to_type(tp_orig);
261 if (!is_Class_type(tp_cast) || !is_Class_type(tp_pred) || !is_Class_type(tp_orig))
264 if (is_SubClass_of(tp_pred, tp_cast) && get_opt_suppress_downcast_optimization())
267 if (tp_cast == tp_orig) {
268 exchange(cast, orig);
269 n_casts_removed += 2;
273 if (!(is_SubClass_of (tp_cast, tp_orig) || is_SubClass_of (tp_orig, tp_cast))) {
274 /* Avoid (B2)(A)(new B1()) --> (B2)(new B1())
275 * if B1 =!> B2 and B2 =!> B1
280 if ((is_SubClass_of (tp_cast, tp_pred) && is_SuperClass_of(tp_pred, tp_orig)) ||
281 (is_SuperClass_of(tp_cast, tp_pred) && is_SubClass_of (tp_pred, tp_orig))) {
282 /* Cast --> Pred --> Orig */
283 set_Cast_op(cast, orig);
291 * Optimize Sel(Cast(type, ptr), ent) into Sel(ptr_type, ent_type)
293 * @param sel the Sel node
295 * @return 1 if Cast's where removed
297 static int concretize_selected_entity(ir_node *sel)
301 ir_entity *sel_ent = get_Sel_entity(sel);
302 ir_node *cast = get_Sel_ptr(sel);
303 while (is_Cast(cast)) {
304 ir_type *cast_tp = get_Cast_type(cast);
305 ir_node *ptr = get_Cast_op(cast);
306 ir_type *orig_tp = get_irn_typeinfo_type(ptr);
308 /* we handle only classes */
309 if (!is_Pointer_type(orig_tp)|| !is_Pointer_type(cast_tp))
311 orig_tp = get_pointer_points_to_type(orig_tp);
312 cast_tp = get_pointer_points_to_type(cast_tp);
313 if (!is_Class_type(orig_tp) || !is_Class_type(cast_tp))
316 /* We only want to concretize, but not generalize. */
317 if (!is_SuperClass_of(cast_tp, orig_tp))
320 /* The sel entity should be a member of the cast_tp, else
321 the graph was not properly typed. */
322 if (get_class_member_index(cast_tp, sel_ent) == (size_t)-1)
325 ir_entity *new_ent = resolve_ent_polymorphy(orig_tp, sel_ent);
327 /* New ent must be member of orig_tp. */
328 if (get_class_member_index(orig_tp, new_ent) == (size_t)-1)
331 /* all checks done, we can remove the Cast and update the Sel */
332 set_Sel_entity(sel, new_ent);
333 set_Sel_ptr(sel, ptr);
334 ++n_sels_concretized;
344 * Move Casts of the same type through a Phi node, i.e.
345 * Phi(Cast(type, x_0), ..., Cast(type, x_n)) -> Cast(type, Phi(x_0, ..., x_n))
347 * @param phi the Phi node
349 * @return 1 if Cast's where moved
351 static int concretize_Phi_type(ir_node *phi)
353 int n_preds = get_Phi_n_preds(phi);
354 ir_node **pred = ALLOCAN(ir_node*, n_preds);
362 pred[0] = get_Phi_pred(phi, 0);
364 if (!is_Cast(pred[0]))
367 if (!is_Cast_upcast(pred[0]))
370 fromtype = get_irn_typeinfo_type(get_Cast_op(pred[0]));
371 totype = get_Cast_type(pred[0]);
373 pred[0] = get_Cast_op(pred[0]);
374 for (i = 1; i < n_preds; ++i) {
375 pred[i] = get_Phi_pred(phi, i);
376 if (!is_Cast(pred[i]))
378 if (get_irn_typeinfo_type(get_Cast_op(pred[i])) != fromtype)
380 pred[i] = get_Cast_op(pred[i]);
384 blk = get_nodes_block(phi);
385 nn = new_r_Phi(blk, n_preds, pred, get_irn_mode(phi));
386 set_irn_typeinfo_type(nn, fromtype);
387 nn = new_r_Cast(blk, nn, totype);
388 set_irn_typeinfo_type(nn, totype);
394 * Remove Casted null checks, i.e.
396 * Cmp(Cast(type, x_orig), NULL_type) -> Cmp(x_orig, NULL_orig)
398 * @param cmp the Cmp node
400 * @return 1 if Cast's where removed
402 static int remove_Cmp_Null_cast(ir_node *cmp)
405 ir_node *cast, *null, *new_null;
406 int cast_pos, null_pos;
410 cast = get_Cmp_left(cmp);
411 if (!is_Cast(cast)) {
414 cast = get_Cmp_right(cmp);
419 null = get_Cmp_right(cmp);
424 if (! is_Const(null))
426 mode = get_irn_mode(null);
427 if (!mode_is_reference(mode))
429 if (get_Const_tarval(null) != get_mode_null(mode))
433 irg = get_irn_irg(cmp);
434 set_irn_n(cmp, cast_pos, get_Cast_op(cast));
435 fromtype = get_irn_typeinfo_type(get_Cast_op(cast));
436 new_null = new_r_Const(irg, get_Const_tarval(null));
437 set_irn_typeinfo_type(new_null, fromtype);
438 set_irn_n(cmp, null_pos, new_null);
444 * Post-Walker: Optimize class casts (mostly by trying to remove them)
446 static void irn_optimize_class_cast(ir_node *n, void *env)
448 int *changed = (int*)env;
451 *changed |= cancel_out_casts(n);
453 *changed |= concretize_selected_entity(n);
455 *changed |= concretize_Phi_type(n);
457 *changed |= remove_Cmp_Null_cast(n);
460 void optimize_class_casts(void)
465 if (get_irp_typeinfo_state() != ir_typeinfo_consistent)
466 simple_analyse_types();
470 all_irg_walk(NULL, irn_optimize_class_cast, &changed);
472 DB((dbg, SET_LEVEL_1, " Cast optimization: %zu Casts removed, %zu Sels concretized.\n",
473 n_casts_removed, n_sels_concretized));
476 void firm_init_class_casts_opt(void)
478 FIRM_DBG_REGISTER(dbg, "firm.opt.tropt");