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 "opt_polymorphy.h"
31 #include "iroptimize.h"
39 #include "iropt_dbg.h"
43 * Checks if a graph allocates new memory and returns the
44 * type of the newly allocated entity.
45 * Returns NULL if the graph did not represent an Allocation.
47 * The default implementation hecks for Alloc nodes only.
49 static ir_type *default_firm_get_Alloc(ir_node *n)
53 return get_Alloc_type(n);
58 /** The get_Alloc function */
59 static get_Alloc_func firm_get_Alloc = default_firm_get_Alloc;
61 /** Set a new get_Alloc_func and returns the old one. */
62 get_Alloc_func firm_set_Alloc_func(get_Alloc_func newf)
64 get_Alloc_func old = firm_get_Alloc;
65 firm_get_Alloc = newf;
69 /** Return dynamic type of ptr.
71 * If we can deduct the dynamic type from the firm nodes
72 * by a limited test we return the dynamic type. Else
73 * we return unknown_type.
75 * If we find a dynamic type this means that the pointer always points
76 * to an object of this type during runtime. We resolved polymorphy.
78 static ir_type *get_dynamic_type(ir_node *ptr)
82 /* skip Cast and Confirm nodes */
84 ir_opcode code = get_irn_opcode(ptr);
88 ptr = get_Cast_op(ptr);
91 ptr = get_Confirm_value(ptr);
98 tp = (*firm_get_Alloc)(ptr);
99 return tp ? tp : firm_unknown_type;
103 * Check, if an entity is final, i.e. is not anymore overridden.
105 static int is_final_ent(ir_entity *ent)
107 if (is_entity_final(ent)) {
108 /* not possible to override this entity. */
111 if (get_opt_closed_world() && get_entity_n_overwrittenby(ent) == 0) {
112 /* we have a closed world, so simply check how often it was
120 * Transform Sel[method] to SymC[method] if possible.
122 ir_node *transform_node_Sel(ir_node *node)
124 ir_node *new_node, *ptr;
126 ir_entity *ent = get_Sel_entity(node);
128 if (get_irp_phase_state() == phase_building) return node;
130 if (!(get_opt_optimize() && get_opt_dyn_meth_dispatch()))
133 if (!is_Method_type(get_entity_type(ent)))
136 /* If the entity is a leave in the inheritance tree,
137 we can replace the Sel by a constant. */
138 if (is_final_ent(ent)) {
139 /* In dead code, we might call a leave entity that is a description.
140 Do not turn the Sel to a SymConst. */
141 if (get_entity_peculiarity(ent) == peculiarity_description) {
142 /* We could remove the Call depending on this Sel. */
145 ir_node *rem_block = get_cur_block();
146 set_cur_block(get_nodes_block(node));
147 new_node = copy_const_value(get_irn_dbg_info(node), get_atomic_ent_value(ent));
148 set_cur_block(rem_block);
149 DBG_OPT_POLY(node, new_node);
154 /* If we know the dynamic type, we can replace the Sel by a constant. */
155 ptr = get_Sel_ptr(node); /* The address we select from. */
156 dyn_tp = get_dynamic_type(ptr); /* The runtime type of ptr. */
158 if (dyn_tp != firm_unknown_type) {
159 ir_entity *called_ent;
162 /* We know which method will be called, no dispatch necessary. */
163 called_ent = resolve_ent_polymorphy(dyn_tp, ent);
165 rem_block = get_cur_block();
166 set_cur_block(get_nodes_block(node));
167 new_node = copy_const_value(get_irn_dbg_info(node), get_atomic_ent_value(called_ent));
168 set_cur_block(rem_block);
169 DBG_OPT_POLY(node, new_node);
177 /* Transform Load(Sel(Alloc)[constant static entity])
178 * to Const[constant static entity value].
180 * This function returns a node replacing the Proj(Load)[Value].
181 * If this is actually called in transform_node, we must build
182 * a tuple, or replace the Projs of the load.
183 * Therefore we call this optimization in ldstopt().
185 ir_node *transform_polymorph_Load(ir_node *load)
187 ir_node *new_node = NULL;
188 ir_node *field_ptr, *ptr;
192 if (!(get_opt_optimize() && get_opt_dyn_meth_dispatch()))
195 field_ptr = get_Load_ptr(load);
197 if (! is_Sel(field_ptr)) return load;
199 ent = get_Sel_entity(field_ptr);
200 if ( !(get_entity_linkage(ent) & IR_LINKAGE_CONSTANT) )
203 /* If the entity is a leave in the inheritance tree,
204 we can replace the Sel by a constant. */
205 if ((get_irp_phase_state() != phase_building) && is_final_ent(ent)) {
206 new_node = get_atomic_ent_value(ent);
208 /* If we know the dynamic type, we can replace the Sel by a constant. */
209 ptr = get_Sel_ptr(field_ptr); /* The address we select from. */
210 dyn_tp = get_dynamic_type(ptr); /* The runtime type of ptr. */
212 if (dyn_tp != firm_unknown_type) {
213 ir_entity *loaded_ent;
215 /* We know which method will be called, no dispatch necessary. */
216 loaded_ent = resolve_ent_polymorphy(dyn_tp, ent);
217 new_node = get_atomic_ent_value(loaded_ent);
220 if (new_node != NULL) {
221 new_node = can_replace_load_by_const(load, new_node);
222 if (new_node != NULL) {
223 DBG_OPT_POLY(field_ptr, new_node);