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  */
  25 #include "config.h"
  26
  27 #include "iroptimize.h"
  28 #include "typerep.h"
  29 #include "type_t.h"
  30 #include "entity_t.h"
  31 #include "irprog_t.h"
  32 #include "irprintf.h"
  33 #include "irpass.h"
  34 #include "irgwalk.h"
  35 #include "error.h"
  36 #include "debug.h"
  37
  38 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
  39
  40 static void visit_entity(ir_entity *entity);
  41
  42 static void visit_node(ir_node *node, void *env)
  43 {
  44         ir_entity *entity;
  45         (void) env;
  46
  47         if (is_SymConst(node)) {
  48                 if (!SYMCONST_HAS_ENT(get_SymConst_kind(node)))
  49                         return;
  50                 entity = get_SymConst_entity(node);
  51         } else if (is_Sel(node)) {
  52                 entity = get_Sel_entity(node);
  53         } else {
  54                 return;
  55         }
  56
  57         visit_entity(entity);
  58 }
  59
  60 static void start_visit_node(ir_node *node)
  61 {
  62         ir_graph *irg = get_irn_irg(node);
  63
  64         if (get_irg_visited(irg) < get_max_irg_visited()) {
  65                 set_irg_visited(irg, get_max_irg_visited());
  66         }
  67         irg_walk_2(node, visit_node, NULL, NULL);
  68 }
  69
  70 static void visit_initializer(ir_initializer_t *initializer)
  71 {
  72         switch (initializer->kind) {
  73         case IR_INITIALIZER_CONST:
  74                 start_visit_node(initializer->consti.value);
  75                 return;
  76         case IR_INITIALIZER_TARVAL:
  77         case IR_INITIALIZER_NULL:
  78                 return;
  79
  80         case IR_INITIALIZER_COMPOUND: {
  81                 size_t i;
  82                 for (i = 0; i < initializer->compound.n_initializers; ++i) {
  83                         ir_initializer_t *subinitializer
  84                                 = initializer->compound.initializers[i];
  85                         visit_initializer(subinitializer);
  86                 }
  87                 return;
  88         }
  89         }
  90         panic("invalid initializer found");
  91 }
  92
  93 static void visit_entity(ir_entity *entity)
  94 {
  95         ir_graph *irg;
  96
  97         if (entity_visited(entity))
  98                 return;
  99         mark_entity_visited(entity);
 100
 101         if (entity->initializer != NULL) {
 102                 visit_initializer(entity->initializer);
 103         }
 104
 105         irg = get_entity_irg(entity);
 106         if (irg != NULL) {
 107                 start_visit_node(get_irg_end(irg));
 108         }
 109 }
 110
 111 static void visit_segment(ir_type *segment)
 112 {
 113         int n_entities = get_compound_n_members(segment);
 114         int i;
 115
 116         for (i = 0; i < n_entities; ++i) {
 117                 ir_entity *entity = get_compound_member(segment, i);
 118                 if (get_entity_visibility(entity) != ir_visibility_external
 119                                 && !(get_entity_linkage(entity) & IR_LINKAGE_HIDDEN_USER)
 120                                 && !(get_entity_linkage(entity) & IR_LINKAGE_NO_CODEGEN))
 121                         continue;
 122
 123                 visit_entity(entity);
 124         }
 125 }
 126
 127 static void garbage_collect_in_segment(ir_type *segment)
 128 {
 129         int i;
 130
 131         for (i = get_compound_n_members(segment)-1; i >= 0; --i) {
 132                 ir_entity *entity = get_compound_member(segment, i);
 133
 134                 if (entity_visited(entity))
 135                         continue;
 136
 137                 DB((dbg, LEVEL_1, "  removing entity %+F\n", entity));
 138
 139                 free_entity(entity);
 140         }
 141 }
 142
 143 void garbage_collect_entities(void)
 144 {
 145         size_t       i;
 146         ir_segment_t s;
 147
 148         FIRM_DBG_REGISTER(dbg, "firm.opt.garbagecollect");
 149
 150         /* start a type walk for all externally visible entities */
 151         irp_reserve_resources(irp, IRP_RESOURCE_TYPE_VISITED);
 152         inc_master_type_visited();
 153         inc_max_irg_visited();
 154
 155         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 156                 ir_type *type = get_segment_type(s);
 157                 mark_type_visited(type);
 158
 159                 visit_segment(type);
 160         }
 161
 162         /* remove graphs of non-visited functions
 163          * (we have to count backwards, because freeing the graph moves the last
 164          *  graph in the list to the free position) */
 165         for (i = get_irp_n_irgs(); i > 0;) {
 166                 ir_graph  *irg    = get_irp_irg(--i);
 167                 ir_entity *entity = get_irg_entity(irg);
 168
 169                 if (entity_visited(entity))
 170                         continue;
 171
 172                 DB((dbg, LEVEL_1, "  freeing method %+F\n", entity));
 173                 free_ir_graph(irg);
 174         }
 175
 176         /* we can now remove all non-visited (global) entities */
 177         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 178                 ir_type *type = get_segment_type(s);
 179                 garbage_collect_in_segment(type);
 180         }
 181         irp_free_resources(irp, IRP_RESOURCE_TYPE_VISITED);
 182 }
 183
 184 ir_prog_pass_t *garbage_collect_entities_pass(const char *name)
 185 {
 186         return def_prog_pass(name ? name : "garbage_collect",
 187                              garbage_collect_entities);
 188 }