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 Optimize polymorphic Sel and Load nodes.
23 * @author Goetz Lindenmaier, Michael Beck
26 * This file subsumes optimization code from cgana.
30 #include "iroptimize.h"
38 #include "iropt_dbg.h"
42 * Checks if a graph allocates new memory and returns the
43 * type of the newly allocated entity.
44 * Returns NULL if the graph did not represent an Allocation.
46 * The default implementation hecks for Alloc nodes only.
48 ir_type *default_firm_get_Alloc(ir_node *n)
52 return get_Alloc_type(n);
57 /** The get_Alloc function */
58 static get_Alloc_func firm_get_Alloc = default_firm_get_Alloc;
60 /** Set a new get_Alloc_func and returns the old one. */
61 get_Alloc_func firm_set_Alloc_func(get_Alloc_func newf)
63 get_Alloc_func old = firm_get_Alloc;
64 firm_get_Alloc = newf;
68 /** Return dynamic type of ptr.
70 * If we can deduct the dynamic type from the firm nodes
71 * by a limited test we return the dynamic type. Else
72 * we return unknown_type.
74 * If we find a dynamic type this means that the pointer always points
75 * to an object of this type during runtime. We resolved polymorphy.
77 static ir_type *get_dynamic_type(ir_node *ptr)
81 /* skip Cast and Confirm nodes */
83 ir_opcode code = get_irn_opcode(ptr);
87 ptr = get_Cast_op(ptr);
90 ptr = get_Confirm_value(ptr);
97 tp = (*firm_get_Alloc)(ptr);
98 return tp ? tp : firm_unknown_type;
102 * Check, if an entity is final, i.e. is not anymore overridden.
104 static int is_final_ent(ir_entity *ent)
106 if (is_entity_final(ent)) {
107 /* not possible to override this entity. */
110 if (get_opt_closed_world() && get_entity_n_overwrittenby(ent) == 0) {
111 /* we have a closed world, so simply check how often it was
119 * Transform Sel[method] to SymC[method] if possible.
121 ir_node *transform_node_Sel(ir_node *node)
123 ir_node *new_node, *ptr;
125 ir_entity *ent = get_Sel_entity(node);
127 if (get_irp_phase_state() == phase_building) return node;
129 if (!(get_opt_optimize() && get_opt_dyn_meth_dispatch()))
132 if (!is_Method_type(get_entity_type(ent)))
135 /* If the entity is a leave in the inheritance tree,
136 we can replace the Sel by a constant. */
137 if (is_final_ent(ent)) {
138 /* In dead code, we might call a leave entity that is a description.
139 Do not turn the Sel to a SymConst. */
140 if (get_entity_peculiarity(ent) == peculiarity_description) {
141 /* We could remove the Call depending on this Sel. */
144 ir_node *rem_block = get_cur_block();
145 set_cur_block(get_nodes_block(node));
146 new_node = copy_const_value(get_irn_dbg_info(node), get_atomic_ent_value(ent));
147 set_cur_block(rem_block);
148 DBG_OPT_POLY(node, new_node);
153 /* If we know the dynamic type, we can replace the Sel by a constant. */
154 ptr = get_Sel_ptr(node); /* The address we select from. */
155 dyn_tp = get_dynamic_type(ptr); /* The runtime type of ptr. */
157 if (dyn_tp != firm_unknown_type) {
158 ir_entity *called_ent;
161 /* We know which method will be called, no dispatch necessary. */
162 called_ent = resolve_ent_polymorphy(dyn_tp, ent);
164 rem_block = get_cur_block();
165 set_cur_block(get_nodes_block(node));
166 new_node = copy_const_value(get_irn_dbg_info(node), get_atomic_ent_value(called_ent));
167 set_cur_block(rem_block);
168 DBG_OPT_POLY(node, new_node);
176 /* Transform Load(Sel(Alloc)[constant static entity])
177 * to Const[constant static entity value].
179 * This function returns a node replacing the Proj(Load)[Value].
180 * If this is actually called in transform_node, we must build
181 * a tuple, or replace the Projs of the load.
182 * Therefore we call this optimization in ldstopt().
184 ir_node *transform_polymorph_Load(ir_node *load)
186 ir_node *new_node = NULL;
187 ir_node *field_ptr, *ptr;
191 if (!(get_opt_optimize() && get_opt_dyn_meth_dispatch()))
194 field_ptr = get_Load_ptr(load);
196 if (! is_Sel(field_ptr)) return load;
198 ent = get_Sel_entity(field_ptr);
199 if ( !(get_entity_linkage(ent) & IR_LINKAGE_CONSTANT) )
202 /* If the entity is a leave in the inheritance tree,
203 we can replace the Sel by a constant. */
204 if ((get_irp_phase_state() != phase_building) && is_final_ent(ent)) {
205 new_node = get_atomic_ent_value(ent);
207 /* If we know the dynamic type, we can replace the Sel by a constant. */
208 ptr = get_Sel_ptr(field_ptr); /* The address we select from. */
209 dyn_tp = get_dynamic_type(ptr); /* The runtime type of ptr. */
211 if (dyn_tp != firm_unknown_type) {
212 ir_entity *loaded_ent;
214 /* We know which method will be called, no dispatch necessary. */
215 loaded_ent = resolve_ent_polymorphy(dyn_tp, ent);
216 new_node = get_atomic_ent_value(loaded_ent);
219 if (new_node != NULL) {
220 new_node = can_replace_load_by_const(load, new_node);
221 if (new_node != NULL) {
222 DBG_OPT_POLY(field_ptr, new_node);