2 * Copyright (C) 1995-2007 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 * File name: ir/opt/opt_polymorphy
23 * Purpose: Optimize polymorphic Sel nodes.
24 * Author: Goetz Lindenmaier, Michael Beck
27 * Copyright: (c) 2005 Universität Karlsruhe
40 #include "iropt_dbg.h"
44 * Checks if a graph allocates new memory and returns the
45 * type of the newly allocated entity.
46 * Returns NULL if the graph did not represent an Allocation.
48 * The default implementation hecks for Alloc nodes only.
50 ir_type *default_firm_get_Alloc(ir_node *n) {
52 if (get_irn_op(n) == op_Alloc) {
53 return get_Alloc_type(n);
58 typedef ir_type *(*get_Alloc_func)(ir_node *n);
60 /** The get_Alloc function */
61 static get_Alloc_func firm_get_Alloc = default_firm_get_Alloc;
63 /** Set a new get_Alloc_func and returns the old one. */
64 get_Alloc_func firm_set_Alloc_func(get_Alloc_func newf) {
65 get_Alloc_func old = firm_get_Alloc;
66 firm_get_Alloc = newf;
70 /** Return dynamic type of ptr.
72 * If we can deduct the dynamic type from the firm nodes
73 * by a limited test we return the dynamic type. Else
74 * we return unknown_type.
76 * If we find a dynamic type this means that the pointer always points
77 * to an object of this type during runtime. We resolved polymorphy.
79 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) {
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);
163 /* called_ent may not be description: has no Address/Const to Call! */
164 assert(get_entity_peculiarity(called_ent) != peculiarity_description);
166 rem_block = get_cur_block();
167 set_cur_block(get_nodes_block(node));
168 new_node = copy_const_value(get_irn_dbg_info(node), get_atomic_ent_value(called_ent));
169 set_cur_block(rem_block);
170 DBG_OPT_POLY(node, new_node);
178 /* Transform Load(Sel(Alloc)[constant static entity])
179 * to Const[constant static entity value].
181 * This function returns a node replacing the Proj(Load)[Value].
182 * If this is actually called in transform_node, we must build
183 * a tuple, or replace the Projs of the load.
184 * Therefore we call this optimization in ldstopt().
186 ir_node *transform_node_Load(ir_node *n)
188 ir_node *field_ptr, *new_node, *ptr;
192 if (!(get_opt_optimize() && get_opt_dyn_meth_dispatch()))
195 field_ptr = get_Load_ptr(n);
197 if (! is_Sel(field_ptr)) return n;
199 ent = get_Sel_entity(field_ptr);
200 if ((get_entity_allocation(ent) != allocation_static) ||
201 (get_entity_variability(ent) != variability_constant) )
204 /* If the entity is a leave in the inheritance tree,
205 we can replace the Sel by a constant. */
206 if ((get_irp_phase_state() != phase_building) && is_final_ent(ent)) {
207 new_node = copy_const_value(get_irn_dbg_info(n), get_atomic_ent_value(ent));
208 DBG_OPT_POLY(field_ptr, new_node);
213 /* If we know the dynamic type, we can replace the Sel by a constant. */
214 ptr = get_Sel_ptr(field_ptr); /* The address we select from. */
215 dyn_tp = get_dynamic_type(ptr); /* The runtime type of ptr. */
217 if (dyn_tp != firm_unknown_type) {
218 ir_entity *loaded_ent;
220 /* We know which method will be called, no dispatch necessary. */
221 loaded_ent = resolve_ent_polymorphy(dyn_tp, ent);
222 /* called_ent may not be description: has no Address/Const to Call! */
223 assert(get_entity_peculiarity(loaded_ent) != peculiarity_description);
225 new_node = copy_const_value(get_irn_dbg_info(n), get_atomic_ent_value(loaded_ent));
226 DBG_OPT_POLY(field_ptr, new_node);