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

   1 /*
   2  * This file is part of libFirm.
   3  * Copyright (C) 2012 University of Karlsruhe.
   4  */
   5
   6 /**
   7  * @file
   8  * @brief    Removal of unreachable methods.
   9  * @author   Matthias Braun
  10  */
  11 #include "config.h"
  12
  13 #include "iroptimize.h"
  14 #include "typerep.h"
  15 #include "type_t.h"
  16 #include "entity_t.h"
  17 #include "irprog_t.h"
  18 #include "irprintf.h"
  19 #include "irpass.h"
  20 #include "irgwalk.h"
  21 #include "error.h"
  22 #include "debug.h"
  23
  24 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
  25
  26 static void visit_entity(ir_entity *entity);
  27
  28 static void visit_node(ir_node *node, void *env)
  29 {
  30         ir_entity *entity;
  31         (void) env;
  32
  33         if (is_SymConst(node)) {
  34                 if (!SYMCONST_HAS_ENT(get_SymConst_kind(node)))
  35                         return;
  36                 entity = get_SymConst_entity(node);
  37         } else if (is_Sel(node)) {
  38                 entity = get_Sel_entity(node);
  39         } else {
  40                 return;
  41         }
  42
  43         visit_entity(entity);
  44 }
  45
  46 static void start_visit_node(ir_node *node)
  47 {
  48         ir_graph *irg = get_irn_irg(node);
  49
  50         if (get_irg_visited(irg) < get_max_irg_visited()) {
  51                 set_irg_visited(irg, get_max_irg_visited());
  52         }
  53         irg_walk_2(node, visit_node, NULL, NULL);
  54 }
  55
  56 static void visit_initializer(ir_initializer_t *initializer)
  57 {
  58         switch (initializer->kind) {
  59         case IR_INITIALIZER_CONST:
  60                 start_visit_node(initializer->consti.value);
  61                 return;
  62         case IR_INITIALIZER_TARVAL:
  63         case IR_INITIALIZER_NULL:
  64                 return;
  65
  66         case IR_INITIALIZER_COMPOUND: {
  67                 size_t i;
  68                 for (i = 0; i < initializer->compound.n_initializers; ++i) {
  69                         ir_initializer_t *subinitializer
  70                                 = initializer->compound.initializers[i];
  71                         visit_initializer(subinitializer);
  72                 }
  73                 return;
  74         }
  75         }
  76         panic("invalid initializer found");
  77 }
  78
  79 static void visit_entity(ir_entity *entity)
  80 {
  81         ir_graph *irg;
  82
  83         if (entity_visited(entity))
  84                 return;
  85         mark_entity_visited(entity);
  86
  87         if (entity->initializer != NULL) {
  88                 visit_initializer(entity->initializer);
  89         }
  90
  91         irg = get_entity_irg(entity);
  92         if (irg != NULL) {
  93                 start_visit_node(get_irg_end(irg));
  94         }
  95 }
  96
  97 static void visit_segment(ir_type *segment)
  98 {
  99         int n_entities = get_compound_n_members(segment);
 100         int i;
 101
 102         for (i = 0; i < n_entities; ++i) {
 103                 ir_entity *entity = get_compound_member(segment, i);
 104                 if (get_entity_visibility(entity) != ir_visibility_external
 105                                 && !(get_entity_linkage(entity) & IR_LINKAGE_HIDDEN_USER)
 106                                 && !(get_entity_linkage(entity) & IR_LINKAGE_NO_CODEGEN))
 107                         continue;
 108
 109                 visit_entity(entity);
 110         }
 111 }
 112
 113 static void garbage_collect_in_segment(ir_type *segment)
 114 {
 115         int i;
 116
 117         for (i = get_compound_n_members(segment)-1; i >= 0; --i) {
 118                 ir_entity *entity = get_compound_member(segment, i);
 119
 120                 if (entity_visited(entity))
 121                         continue;
 122
 123                 DB((dbg, LEVEL_1, "  removing entity %+F\n", entity));
 124
 125                 free_entity(entity);
 126         }
 127 }
 128
 129 void garbage_collect_entities(void)
 130 {
 131         size_t       i;
 132         ir_segment_t s;
 133
 134         FIRM_DBG_REGISTER(dbg, "firm.opt.garbagecollect");
 135
 136         /* start a type walk for all externally visible entities */
 137         irp_reserve_resources(irp, IRP_RESOURCE_TYPE_VISITED);
 138         inc_master_type_visited();
 139         inc_max_irg_visited();
 140
 141         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 142                 ir_type *type = get_segment_type(s);
 143                 mark_type_visited(type);
 144
 145                 visit_segment(type);
 146         }
 147
 148         /* remove graphs of non-visited functions
 149          * (we have to count backwards, because freeing the graph moves the last
 150          *  graph in the list to the free position) */
 151         for (i = get_irp_n_irgs(); i > 0;) {
 152                 ir_graph  *irg    = get_irp_irg(--i);
 153                 ir_entity *entity = get_irg_entity(irg);
 154
 155                 if (entity_visited(entity))
 156                         continue;
 157
 158                 DB((dbg, LEVEL_1, "  freeing method %+F\n", entity));
 159                 free_ir_graph(irg);
 160         }
 161
 162         /* we can now remove all non-visited (global) entities */
 163         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; ++s) {
 164                 ir_type *type = get_segment_type(s);
 165                 garbage_collect_in_segment(type);
 166         }
 167         irp_free_resources(irp, IRP_RESOURCE_TYPE_VISITED);
 168 }
 169
 170 ir_prog_pass_t *garbage_collect_entities_pass(const char *name)
 171 {
 172         return def_prog_pass(name ? name : "garbage_collect",
 173                              garbage_collect_entities);
 174 }