nsz Git - libfirm/blob - ir/opt/garbage_collect.c

   1 /*
   2  * Copyright (C) 2010 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   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.
  10  *
  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.
  14  *
  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
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief    Removal of unreachable methods.
  23  * @author   Matthias Braun
  24  * @version  $Id$
  25  */
  26 #include "config.h"
  27
  28 #include "iroptimize.h"
  29 #include "typerep.h"
  30 #include "type_t.h"
  31 #include "entity_t.h"
  32 #include "irprog_t.h"
  33 #include "irprintf.h"
  34 #include "irpass.h"
  35 #include "irgwalk.h"
  36 #include "error.h"
  37 #include "debug.h"
  38
  39 DEBUG_ONLY(static firm_dbg_module_t *dbg);
  40
  41 static void visit_entity(ir_entity *entity);
  42
  43 static void visit_node(ir_node *node, void *env)
  44 {
  45         ir_entity *entity;
  46         (void) env;
  47
  48         if (!is_SymConst(node))
  49                 return;
  50         if (!SYMCONST_HAS_ENT(get_SymConst_kind(node)))
  51                 return;
  52
  53         entity = get_SymConst_entity(node);
  54         visit_entity(entity);
  55 }
  56
  57 static void start_visit_node(ir_node *node)
  58 {
  59         ir_graph *irg = get_irn_irg(node);
  60
  61         if (get_irg_visited(irg) < get_max_irg_visited()) {
  62                 set_irg_visited(irg, get_max_irg_visited());
  63         }
  64         current_ir_graph = irg;
  65         irg_walk_2(node, visit_node, NULL, NULL);
  66 }
  67
  68 static void visit_initializer(ir_initializer_t *initializer)
  69 {
  70         switch (initializer->kind) {
  71         case IR_INITIALIZER_CONST:
  72                 start_visit_node(initializer->consti.value);
  73                 return;
  74         case IR_INITIALIZER_TARVAL:
  75         case IR_INITIALIZER_NULL:
  76                 return;
  77
  78         case IR_INITIALIZER_COMPOUND: {
  79                 size_t i;
  80                 for(i = 0; i < initializer->compound.n_initializers; ++i) {
  81                         ir_initializer_t *subinitializer
  82                                 = initializer->compound.initializers[i];
  83                         visit_initializer(subinitializer);
  84                 }
  85                 return;
  86         }
  87         }
  88         panic("invalid initializer found");
  89 }
  90
  91 static void visit_entity(ir_entity *entity)
  92 {
  93         ir_graph *irg;
  94
  95         if (entity_visited(entity))
  96                 return;
  97         mark_entity_visited(entity);
  98
  99         if (entity->initializer != NULL) {
 100                 visit_initializer(entity->initializer);
 101         }  else if (entity_has_compound_ent_values(entity)) {
 102                 int i;
 103                 int n_members = get_compound_ent_n_values(entity);
 104                 for (i = 0; i < n_members; ++i) {
 105                         ir_node *node = get_compound_ent_value(entity, i);
 106                         start_visit_node(node);
 107                 }
 108         }
 109
 110         irg = get_entity_irg(entity);
 111         if (irg != NULL) {
 112                 start_visit_node(get_irg_end(irg));
 113         }
 114 }
 115
 116 static void visit_segment(ir_type *segment)
 117 {
 118         int n_entities = get_compound_n_members(segment);
 119         int i;
 120
 121         for (i = 0; i < n_entities; ++i) {
 122                 ir_entity *entity = get_compound_member(segment, i);
 123                 if (get_entity_visibility(entity) != ir_visibility_default
 124                                 && !(get_entity_linkage(entity) & IR_LINKAGE_HIDDEN_USER))
 125                         continue;
 126
 127                 visit_entity(entity);
 128         }
 129 }
 130
 131 static void garbage_collect_in_segment(ir_type *segment)
 132 {
 133         int i;
 134
 135         for (i = get_compound_n_members(segment)-1; i >= 0; --i) {
 136                 ir_entity *entity = get_compound_member(segment, i);
 137
 138                 if (entity_visited(entity))
 139                         continue;
 140
 141                 DB((dbg, LEVEL_1, "  removing entity %+F\n", entity));
 142
 143                 /* TODO: this is O(n^2) improve our interfaces! */
 144                 remove_class_member(get_entity_owner(entity), entity);
 145         }
 146 }
 147
 148 void garbage_collect_entities(void)
 149 {
 150         int          i;
 151         ir_segment_t s;
 152
 153         FIRM_DBG_REGISTER(dbg, "firm.opt.garbagecollect");
 154
 155         /* start a type walk for all externally visible entities */
 156         irp_reserve_resources(irp, IR_RESOURCE_TYPE_VISITED);
 157         inc_master_type_visited();
 158         inc_max_irg_visited();
 159
 160         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 161                 ir_type *type = get_segment_type(s);
 162                 mark_type_visited(type);
 163
 164                 visit_segment(type);
 165         }
 166
 167         /* remove graphs of non-visited functions
 168          * (we have to count backwards so we can safely call remove_irp_irg
 169          *  while iterating) */
 170         for (i = get_irp_n_irgs()-1; i >= 0; --i) {
 171                 ir_graph  *irg    = get_irp_irg(i);
 172                 ir_entity *entity = get_irg_entity(irg);
 173
 174                 if (entity_visited(entity))
 175                         continue;
 176
 177                 DB((dbg, LEVEL_1, "  freeing method %+F\n",     entity));
 178                 remove_irp_irg(irg);
 179         }
 180
 181         /* we can now remove all non-visited (global) entities */
 182         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 183                 ir_type *type = get_segment_type(s);
 184                 garbage_collect_in_segment(type);
 185         }
 186         irp_free_resources(irp, IR_RESOURCE_TYPE_VISITED);
 187 }
 188
 189 ir_prog_pass_t *garbage_collect_entities_pass(const char *name)
 190 {
 191         return def_prog_pass(name ? name : "garbage_collect",
 192                              garbage_collect_entities);
 193 }