nsz Git - libfirm/blob - ir/be/bespill.c

   1 /*
   2  * Copyright (C) 1995-2008 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       Spill module selection; Preparation steps
  23  * @author      Matthias Braun
  24  * @date        29.09.2005
  25  * @version     $Id$
  26  */
  27 #include "config.h"
  28
  29 #include "irtools.h"
  30 #include "debug.h"
  31 #include "iredges_t.h"
  32 #include "raw_bitset.h"
  33 #include "statev.h"
  34 #include "irgwalk.h"
  35
  36 #include "bespill.h"
  37 #include "bemodule.h"
  38 #include "be.h"
  39 #include "belive_t.h"
  40 #include "beirg.h"
  41 #include "bearch.h"
  42 #include "benode.h"
  43 #include "besched.h"
  44 #include "bera.h"
  45 #include "beintlive_t.h"
  46
  47 #include "lc_opts.h"
  48 #include "lc_opts_enum.h"
  49
  50 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  51
  52 typedef struct be_pre_spill_env_t {
  53         ir_graph                    *irg;
  54         const arch_register_class_t *cls;
  55 } be_pre_spill_env_t;
  56
  57 static void prepare_constr_insn(be_pre_spill_env_t *env, ir_node *node)
  58 {
  59         const arch_register_class_t *cls = env->cls;
  60         ir_node  *block      = get_nodes_block(node);
  61         const ir_graph *irg  = env->irg;
  62         be_irg_t       *birg = be_birg_from_irg(irg);
  63         be_lv_t *lv          = be_get_irg_liveness(irg);
  64         unsigned *tmp        = NULL;
  65         unsigned *def_constr = NULL;
  66         int       arity      = get_irn_arity(node);
  67         ir_node  *def;
  68
  69         int i, i2;
  70
  71         /* Insert a copy for constraint inputs attached to a value which can't
  72          * fulfill the constraint
  73          * (typical example: stack pointer as input to copyb)
  74          * TODO: This really just checks precolored registers at the moment and
  75          *       ignores the general case of not matching in/out constraints
  76          */
  77         for (i = 0; i < arity; ++i) {
  78                 ir_node                   *op  = get_irn_n(node, i);
  79                 const arch_register_req_t *req = arch_get_irn_register_req_in(node, i);
  80                 const arch_register_t     *reg;
  81                 ir_node                   *copy;
  82
  83                 if (req->cls != cls)
  84                         continue;
  85                 reg = arch_get_irn_register(op);
  86                 if (reg == NULL)
  87                         continue;
  88
  89                 /* precolored with an ignore register (which is not a joker like
  90                    unknown/noreg) */
  91                 if ((reg->type & arch_register_type_joker) ||
  92                     rbitset_is_set(birg->allocatable_regs, reg->global_index))
  93                         continue;
  94
  95                 if (! (req->type & arch_register_req_type_limited))
  96                         continue;
  97                 if (rbitset_is_set(req->limited, reg->index))
  98                         continue;
  99
 100                 copy = be_new_Copy(cls, block, op);
 101                 stat_ev_int("constr_copy", 1);
 102                 sched_add_before(node, copy);
 103                 set_irn_n(node, i, copy);
 104                 DBG((dbg, LEVEL_3, "inserting ignore arg copy %+F for %+F pos %d\n",
 105                      copy, node, i));
 106         }
 107
 108         /* insert copies for nodes that occur constrained more than once. */
 109         for (i = 0; i < arity; ++i) {
 110                 ir_node                   *in;
 111                 ir_node                   *copy;
 112                 const arch_register_req_t *req;
 113
 114                 req = arch_get_irn_register_req_in(node, i);
 115                 if (req->cls != cls)
 116                         continue;
 117
 118                 if (! (req->type & arch_register_req_type_limited))
 119                         continue;
 120
 121                 in = get_irn_n(node, i);
 122                 if (!arch_irn_consider_in_reg_alloc(cls, in))
 123                         continue;
 124
 125                 for (i2 = i + 1; i2 < arity; ++i2) {
 126                         ir_node *in2;
 127                         const arch_register_req_t *req2;
 128
 129                         req2 = arch_get_irn_register_req_in(node, i2);
 130                         if (req2->cls != cls)
 131                                 continue;
 132                         if (! (req2->type & arch_register_req_type_limited))
 133                                 continue;
 134
 135                         in2 = get_irn_n(node, i2);
 136                         if (in2 != in)
 137                                 continue;
 138
 139                         /* if the constraint is the same, no copy is necessary
 140                          * TODO generalise unequal but overlapping constraints */
 141                         if (rbitsets_equal(req->limited, req2->limited, cls->n_regs))
 142                                 continue;
 143
 144                         copy = be_new_Copy(cls, block, in);
 145                         stat_ev_int("constr_copy", 1);
 146
 147                         sched_add_before(node, copy);
 148                         set_irn_n(node, i2, copy);
 149                         DBG((dbg, LEVEL_3,
 150                              "inserting multiple constr copy %+F for %+F pos %d\n",
 151                              copy, node, i2));
 152                 }
 153         }
 154
 155         /* collect all registers occurring in out constraints. */
 156         be_foreach_definition(node, cls, def,
 157                 if (! (req_->type & arch_register_req_type_limited))
 158                         continue;
 159                 if (def_constr == NULL) {
 160                         rbitset_alloca(def_constr, cls->n_regs);
 161                 }
 162                 rbitset_or(def_constr, req_->limited, cls->n_regs);
 163         );
 164
 165         /* no output constraints => we're good */
 166         if (def_constr == NULL) {
 167                 return;
 168         }
 169
 170         /*
 171          * insert copies for all constrained arguments living through the node
 172          * and being constrained to a register which also occurs in out constraints.
 173          */
 174         rbitset_alloca(tmp, cls->n_regs);
 175         for (i = 0; i < arity; ++i) {
 176                 const arch_register_req_t *req;
 177                 ir_node                   *in;
 178                 ir_node                   *copy;
 179
 180                 /*
 181                  * Check, if
 182                  * 1) the operand is constrained.
 183                  * 2) lives through the node.
 184                  * 3) is constrained to a register occurring in out constraints.
 185                  */
 186                 req = arch_get_irn_register_req_in(node, i);
 187                 if (req->cls != cls)
 188                         continue;
 189                 if (!(req->type & arch_register_req_type_limited))
 190                         continue;
 191
 192                 in = get_irn_n(node, i);
 193                 if (!arch_irn_consider_in_reg_alloc(cls, in))
 194                         continue;
 195                 if (!be_values_interfere(lv, node, in))
 196                         continue;
 197
 198                 rbitset_copy(tmp, req->limited, cls->n_regs);
 199                 rbitset_and(tmp, def_constr, cls->n_regs);
 200
 201                 if (rbitset_is_empty(tmp, cls->n_regs))
 202                         continue;
 203
 204                 /*
 205                  * only create the copy if the operand is no copy.
 206                  * this is necessary since the assure constraints phase inserts
 207                  * Copies and Keeps for operands which must be different from the
 208                  * results. Additional copies here would destroy this.
 209                  */
 210                 if (be_is_Copy(in))
 211                         continue;
 212
 213                 copy = be_new_Copy(cls, block, in);
 214                 sched_add_before(node, copy);
 215                 set_irn_n(node, i, copy);
 216                 DBG((dbg, LEVEL_3, "inserting constr copy %+F for %+F pos %d\n",
 217                      copy, node, i));
 218                 be_liveness_update(lv, in);
 219         }
 220 }
 221
 222 static void pre_spill_prepare_constr_walker(ir_node *block, void *data)
 223 {
 224         be_pre_spill_env_t *env = (be_pre_spill_env_t*)data;
 225         ir_node *node;
 226         sched_foreach(block, node) {
 227                 prepare_constr_insn(env, node);
 228         }
 229 }
 230
 231 void be_pre_spill_prepare_constr(ir_graph *irg,
 232                                  const arch_register_class_t *cls)
 233 {
 234         be_pre_spill_env_t env;
 235         memset(&env, 0, sizeof(env));
 236         env.irg = irg;
 237         env.cls = cls;
 238
 239         be_assure_liveness(irg);
 240
 241         irg_block_walk_graph(irg, pre_spill_prepare_constr_walker, NULL, &env);
 242 }
 243
 244
 245
 246 int be_coalesce_spill_slots = 1;
 247 int be_do_remats = 1;
 248
 249 static const lc_opt_table_entry_t be_spill_options[] = {
 250         LC_OPT_ENT_BOOL ("coalesce_slots", "coalesce the spill slots", &be_coalesce_spill_slots),
 251         LC_OPT_ENT_BOOL ("remat", "try to rematerialize values instead of reloading", &be_do_remats),
 252         LC_OPT_LAST
 253 };
 254
 255 static be_module_list_entry_t *spillers = NULL;
 256 static const be_spiller_t *selected_spiller = NULL;
 257
 258 void be_register_spiller(const char *name, be_spiller_t *spiller)
 259 {
 260         if (selected_spiller == NULL)
 261                 selected_spiller = spiller;
 262         be_add_module_to_list(&spillers, name, spiller);
 263 }
 264
 265 void be_do_spill(ir_graph *irg, const arch_register_class_t *cls)
 266 {
 267         assert(selected_spiller != NULL);
 268
 269         selected_spiller->spill(irg, cls);
 270 }
 271
 272 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spilloptions)
 273 void be_init_spilloptions(void)
 274 {
 275         lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
 276         lc_opt_entry_t *spill_grp = lc_opt_get_grp(be_grp, "spill");
 277
 278         lc_opt_add_table(spill_grp, be_spill_options);
 279         be_add_module_list_opt(be_grp, "spiller", "spill algorithm",
 280                                &spillers, (void**) &selected_spiller);
 281
 282         FIRM_DBG_REGISTER(dbg, "firm.be.spillprepare");
 283 }