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

   1 /*
   2  * Copyright (C) 1995-2011 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                 if (!SYMCONST_HAS_ENT(get_SymConst_kind(node)))
  50                         return;
  51                 entity = get_SymConst_entity(node);
  52         } else if (is_Sel(node)) {
  53                 entity = get_Sel_entity(node);
  54         } else {
  55                 return;
  56         }
  57
  58         visit_entity(entity);
  59 }
  60
  61 static void start_visit_node(ir_node *node)
  62 {
  63         ir_graph *irg = get_irn_irg(node);
  64
  65         if (get_irg_visited(irg) < get_max_irg_visited()) {
  66                 set_irg_visited(irg, get_max_irg_visited());
  67         }
  68         irg_walk_2(node, visit_node, NULL, NULL);
  69 }
  70
  71 static void visit_initializer(ir_initializer_t *initializer)
  72 {
  73         switch (initializer->kind) {
  74         case IR_INITIALIZER_CONST:
  75                 start_visit_node(initializer->consti.value);
  76                 return;
  77         case IR_INITIALIZER_TARVAL:
  78         case IR_INITIALIZER_NULL:
  79                 return;
  80
  81         case IR_INITIALIZER_COMPOUND: {
  82                 size_t i;
  83                 for (i = 0; i < initializer->compound.n_initializers; ++i) {
  84                         ir_initializer_t *subinitializer
  85                                 = initializer->compound.initializers[i];
  86                         visit_initializer(subinitializer);
  87                 }
  88                 return;
  89         }
  90         }
  91         panic("invalid initializer found");
  92 }
  93
  94 static void visit_entity(ir_entity *entity)
  95 {
  96         ir_graph *irg;
  97
  98         if (entity_visited(entity))
  99                 return;
 100         mark_entity_visited(entity);
 101
 102         if (entity->initializer != NULL) {
 103                 visit_initializer(entity->initializer);
 104         }  else if (entity_has_compound_ent_values(entity)) {
 105                 size_t i;
 106                 size_t n_members = get_compound_ent_n_values(entity);
 107                 for (i = 0; i < n_members; ++i) {
 108                         ir_node *node = get_compound_ent_value(entity, i);
 109                         start_visit_node(node);
 110                 }
 111         }
 112
 113         irg = get_entity_irg(entity);
 114         if (irg != NULL) {
 115                 start_visit_node(get_irg_end(irg));
 116         }
 117 }
 118
 119 static void visit_segment(ir_type *segment)
 120 {
 121         int n_entities = get_compound_n_members(segment);
 122         int i;
 123
 124         for (i = 0; i < n_entities; ++i) {
 125                 ir_entity *entity = get_compound_member(segment, i);
 126                 if (get_entity_visibility(entity) != ir_visibility_default
 127                                 && !(get_entity_linkage(entity) & IR_LINKAGE_HIDDEN_USER))
 128                         continue;
 129
 130                 visit_entity(entity);
 131         }
 132 }
 133
 134 static void garbage_collect_in_segment(ir_type *segment)
 135 {
 136         int i;
 137
 138         for (i = get_compound_n_members(segment)-1; i >= 0; --i) {
 139                 ir_entity *entity = get_compound_member(segment, i);
 140
 141                 if (entity_visited(entity))
 142                         continue;
 143
 144                 DB((dbg, LEVEL_1, "  removing entity %+F\n", entity));
 145
 146                 free_entity(entity);
 147         }
 148 }
 149
 150 void garbage_collect_entities(void)
 151 {
 152         ssize_t      i;
 153         ir_segment_t s;
 154
 155         FIRM_DBG_REGISTER(dbg, "firm.opt.garbagecollect");
 156
 157         /* start a type walk for all externally visible entities */
 158         irp_reserve_resources(irp, IR_RESOURCE_TYPE_VISITED);
 159         inc_master_type_visited();
 160         inc_max_irg_visited();
 161
 162         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 163                 ir_type *type = get_segment_type(s);
 164                 mark_type_visited(type);
 165
 166                 visit_segment(type);
 167         }
 168
 169         /* remove graphs of non-visited functions
 170          * (we have to count backwards so we can safely call remove_irp_irg
 171          *  while iterating) */
 172         for (i = get_irp_n_irgs()-1; i >= 0; --i) {
 173                 ir_graph  *irg    = get_irp_irg(i);
 174                 ir_entity *entity = get_irg_entity(irg);
 175
 176                 if (entity_visited(entity))
 177                         continue;
 178
 179                 DB((dbg, LEVEL_1, "  freeing method %+F\n", entity));
 180                 remove_irp_irg(irg);
 181         }
 182
 183         /* we can now remove all non-visited (global) entities */
 184         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 185                 ir_type *type = get_segment_type(s);
 186                 garbage_collect_in_segment(type);
 187         }
 188         irp_free_resources(irp, IR_RESOURCE_TYPE_VISITED);
 189 }
 190
 191 ir_prog_pass_t *garbage_collect_entities_pass(const char *name)
 192 {
 193         return def_prog_pass(name ? name : "garbage_collect",
 194                              garbage_collect_entities);
 195 }