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                 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         current_ir_graph = irg;
  69         irg_walk_2(node, visit_node, NULL, NULL);
  70 }
  71
  72 static void visit_initializer(ir_initializer_t *initializer)
  73 {
  74         switch (initializer->kind) {
  75         case IR_INITIALIZER_CONST:
  76                 start_visit_node(initializer->consti.value);
  77                 return;
  78         case IR_INITIALIZER_TARVAL:
  79         case IR_INITIALIZER_NULL:
  80                 return;
  81
  82         case IR_INITIALIZER_COMPOUND: {
  83                 size_t i;
  84                 for (i = 0; i < initializer->compound.n_initializers; ++i) {
  85                         ir_initializer_t *subinitializer
  86                                 = initializer->compound.initializers[i];
  87                         visit_initializer(subinitializer);
  88                 }
  89                 return;
  90         }
  91         }
  92         panic("invalid initializer found");
  93 }
  94
  95 static void visit_entity(ir_entity *entity)
  96 {
  97         ir_graph *irg;
  98
  99         if (entity_visited(entity))
 100                 return;
 101         mark_entity_visited(entity);
 102
 103         if (entity->initializer != NULL) {
 104                 visit_initializer(entity->initializer);
 105         }  else if (entity_has_compound_ent_values(entity)) {
 106                 int i;
 107                 int n_members = get_compound_ent_n_values(entity);
 108                 for (i = 0; i < n_members; ++i) {
 109                         ir_node *node = get_compound_ent_value(entity, i);
 110                         start_visit_node(node);
 111                 }
 112         }
 113
 114         irg = get_entity_irg(entity);
 115         if (irg != NULL) {
 116                 start_visit_node(get_irg_end(irg));
 117         }
 118 }
 119
 120 static void visit_segment(ir_type *segment)
 121 {
 122         int n_entities = get_compound_n_members(segment);
 123         int i;
 124
 125         for (i = 0; i < n_entities; ++i) {
 126                 ir_entity *entity = get_compound_member(segment, i);
 127                 if (get_entity_visibility(entity) != ir_visibility_default
 128                                 && !(get_entity_linkage(entity) & IR_LINKAGE_HIDDEN_USER))
 129                         continue;
 130
 131                 visit_entity(entity);
 132         }
 133 }
 134
 135 static void garbage_collect_in_segment(ir_type *segment)
 136 {
 137         int i;
 138
 139         for (i = get_compound_n_members(segment)-1; i >= 0; --i) {
 140                 ir_entity *entity = get_compound_member(segment, i);
 141
 142                 if (entity_visited(entity))
 143                         continue;
 144
 145                 DB((dbg, LEVEL_1, "  removing entity %+F\n", entity));
 146
 147                 free_entity(entity);
 148         }
 149 }
 150
 151 void garbage_collect_entities(void)
 152 {
 153         int          i;
 154         ir_segment_t s;
 155
 156         FIRM_DBG_REGISTER(dbg, "firm.opt.garbagecollect");
 157
 158         /* start a type walk for all externally visible entities */
 159         irp_reserve_resources(irp, IR_RESOURCE_TYPE_VISITED);
 160         inc_master_type_visited();
 161         inc_max_irg_visited();
 162
 163         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 164                 ir_type *type = get_segment_type(s);
 165                 mark_type_visited(type);
 166
 167                 visit_segment(type);
 168         }
 169
 170         /* remove graphs of non-visited functions
 171          * (we have to count backwards so we can safely call remove_irp_irg
 172          *  while iterating) */
 173         for (i = get_irp_n_irgs()-1; i >= 0; --i) {
 174                 ir_graph  *irg    = get_irp_irg(i);
 175                 ir_entity *entity = get_irg_entity(irg);
 176
 177                 if (entity_visited(entity))
 178                         continue;
 179
 180                 DB((dbg, LEVEL_1, "  freeing method %+F\n", entity));
 181                 remove_irp_irg(irg);
 182         }
 183
 184         /* we can now remove all non-visited (global) entities */
 185         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 186                 ir_type *type = get_segment_type(s);
 187                 garbage_collect_in_segment(type);
 188         }
 189         irp_free_resources(irp, IR_RESOURCE_TYPE_VISITED);
 190 }
 191
 192 ir_prog_pass_t *garbage_collect_entities_pass(const char *name)
 193 {
 194         return def_prog_pass(name ? name : "garbage_collect",
 195                              garbage_collect_entities);
 196 }