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
  68         int i, i2;
  69
  70         /* Insert a copy for constraint inputs attached to a value which can't
  71          * fullfil the constraint
  72          * (typical example: stack pointer as input to copyb)
  73          * TODO: This really just checks precolored registers at the moment and
  74          *       ignores the general case of not matching in/out constraints
  75          */
  76         for (i = 0; i < arity; ++i) {
  77                 ir_node                   *op  = get_irn_n(node, i);
  78                 const arch_register_req_t *req = arch_get_register_req(node, i);
  79                 const arch_register_t     *reg;
  80                 ir_node                   *copy;
  81
  82                 if (req->cls != cls)
  83                         continue;
  84                 reg = arch_get_irn_register(op);
  85                 if (reg == NULL)
  86                         continue;
  87
  88                 /* precolored with an ignore register (which is not a joker like
  89                    unknown/noreg) */
  90                 if (arch_register_type_is(reg, joker)
  91                                 || rbitset_is_set(birg->allocatable_regs, reg->global_index))
  92                         continue;
  93
  94                 if (! (req->type & arch_register_req_type_limited))
  95                         continue;
  96                 if (rbitset_is_set(req->limited, reg->index))
  97                         continue;
  98
  99                 copy = be_new_Copy(cls, block, op);
 100                 stat_ev_int("constr_copy", 1);
 101                 sched_add_before(node, copy);
 102                 set_irn_n(node, i, copy);
 103                 DBG((dbg, LEVEL_3, "inserting ignore arg copy %+F for %+F pos %d\n",
 104                      copy, node, i));
 105         }
 106
 107         /* insert copies for nodes that occur constrained more than once. */
 108         for (i = 0; i < arity; ++i) {
 109                 ir_node                   *in;
 110                 ir_node                   *copy;
 111                 const arch_register_req_t *req;
 112
 113                 req = arch_get_register_req(node, i);
 114                 if (req->cls != cls)
 115                         continue;
 116
 117                 if (! (req->type & arch_register_req_type_limited))
 118                         continue;
 119
 120                 in = get_irn_n(node, i);
 121                 if (!arch_irn_consider_in_reg_alloc(cls, in))
 122                         continue;
 123
 124                 for (i2 = i + 1; i2 < arity; ++i2) {
 125                         ir_node *in2;
 126                         const arch_register_req_t *req2;
 127
 128                         req2 = arch_get_register_req(node, i2);
 129                         if (req2->cls != cls)
 130                                 continue;
 131                         if (! (req2->type & arch_register_req_type_limited))
 132                                 continue;
 133
 134                         in2 = get_irn_n(node, i2);
 135                         if (in2 != in)
 136                                 continue;
 137
 138                         /* if the constraint is the same, no copy is necessary
 139                          * TODO generalise unequal but overlapping constraints */
 140                         if (rbitsets_equal(req->limited, req2->limited, cls->n_regs))
 141                                 continue;
 142
 143                         copy = be_new_Copy(cls, block, in);
 144                         stat_ev_int("constr_copy", 1);
 145
 146                         sched_add_before(node, copy);
 147                         set_irn_n(node, i2, copy);
 148                         DBG((dbg, LEVEL_3,
 149                              "inserting multiple constr copy %+F for %+F pos %d\n",
 150                              copy, node, i2));
 151                 }
 152         }
 153
 154         /* collect all registers occurring in out constraints. */
 155         if (get_irn_mode(node) == mode_T) {
 156                 const ir_edge_t *edge;
 157
 158                 foreach_out_edge(node, edge) {
 159                         ir_node                   *proj = get_edge_src_irn(edge);
 160                         const arch_register_req_t *req  = arch_get_register_req_out(proj);
 161                         if (! (req->type & arch_register_req_type_limited))
 162                                 continue;
 163
 164                         if (def_constr == NULL) {
 165                                 rbitset_alloca(def_constr, cls->n_regs);
 166                         }
 167                         rbitset_or(def_constr, req->limited, cls->n_regs);
 168                 }
 169         } else {
 170                 const arch_register_req_t *req = arch_get_register_req_out(node);
 171                 if (req->type & arch_register_req_type_limited) {
 172                         rbitset_alloca(def_constr, cls->n_regs);
 173                         rbitset_or(def_constr, req->limited, cls->n_regs);
 174                 }
 175         }
 176
 177         /* no output constraints => we're good */
 178         if (def_constr == NULL) {
 179                 return;
 180         }
 181
 182         /*
 183          * insert copies for all constrained arguments living through the node
 184          * and being constrained to a register which also occurs in out constraints.
 185          */
 186         rbitset_alloca(tmp, cls->n_regs);
 187         for (i = 0; i < arity; ++i) {
 188                 const arch_register_req_t *req;
 189                 ir_node                   *in;
 190                 ir_node                   *copy;
 191
 192                 /*
 193                  * Check, if
 194                  * 1) the operand is constrained.
 195                  * 2) lives through the node.
 196                  * 3) is constrained to a register occurring in out constraints.
 197                  */
 198                 req = arch_get_register_req(node, i);
 199                 if (req->cls != cls)
 200                         continue;
 201                 if (!(req->type & arch_register_req_type_limited))
 202                         continue;
 203
 204                 in = get_irn_n(node, i);
 205                 if (!arch_irn_consider_in_reg_alloc(cls, in))
 206                         continue;
 207                 if (!be_values_interfere(lv, node, in))
 208                         continue;
 209
 210                 rbitset_copy(tmp, req->limited, cls->n_regs);
 211                 rbitset_and(tmp, def_constr, cls->n_regs);
 212
 213                 if (rbitset_is_empty(tmp, cls->n_regs))
 214                         continue;
 215
 216                 /*
 217                  * only create the copy if the operand is no copy.
 218                  * this is necessary since the assure constraints phase inserts
 219                  * Copies and Keeps for operands which must be different from the
 220                  * results. Additional copies here would destroy this.
 221                  */
 222                 if (be_is_Copy(in))
 223                         continue;
 224
 225                 copy = be_new_Copy(cls, block, in);
 226                 sched_add_before(node, copy);
 227                 set_irn_n(node, i, copy);
 228                 DBG((dbg, LEVEL_3, "inserting constr copy %+F for %+F pos %d\n",
 229                      copy, node, i));
 230                 be_liveness_update(lv, in);
 231         }
 232 }
 233
 234 static void pre_spill_prepare_constr_walker(ir_node *block, void *data)
 235 {
 236         be_pre_spill_env_t *env = data;
 237         ir_node *node;
 238         sched_foreach(block, node) {
 239                 prepare_constr_insn(env, node);
 240         }
 241 }
 242
 243 void be_pre_spill_prepare_constr(ir_graph *irg,
 244                                  const arch_register_class_t *cls)
 245 {
 246         be_pre_spill_env_t env;
 247         memset(&env, 0, sizeof(env));
 248         env.irg = irg;
 249         env.cls = cls;
 250
 251         be_assure_liveness(irg);
 252
 253         irg_block_walk_graph(irg, pre_spill_prepare_constr_walker, NULL, &env);
 254 }
 255
 256
 257
 258 int be_coalesce_spill_slots = 1;
 259 int be_do_remats = 1;
 260
 261 static const lc_opt_table_entry_t be_spill_options[] = {
 262         LC_OPT_ENT_BOOL ("coalesce_slots", "coalesce the spill slots", &be_coalesce_spill_slots),
 263         LC_OPT_ENT_BOOL ("remat", "try to rematerialize values instead of reloading", &be_do_remats),
 264         LC_OPT_LAST
 265 };
 266
 267 static be_module_list_entry_t *spillers = NULL;
 268 static const be_spiller_t *selected_spiller = NULL;
 269
 270 void be_register_spiller(const char *name, be_spiller_t *spiller)
 271 {
 272         if (selected_spiller == NULL)
 273                 selected_spiller = spiller;
 274         be_add_module_to_list(&spillers, name, spiller);
 275 }
 276
 277 void be_do_spill(ir_graph *irg, const arch_register_class_t *cls)
 278 {
 279         assert(selected_spiller != NULL);
 280
 281         selected_spiller->spill(irg, cls);
 282 }
 283
 284 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spilloptions);
 285 void be_init_spilloptions(void)
 286 {
 287         lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
 288         lc_opt_entry_t *spill_grp = lc_opt_get_grp(be_grp, "spill");
 289
 290         lc_opt_add_table(spill_grp, be_spill_options);
 291         be_add_module_list_opt(spill_grp, "spiller", "spill algorithm",
 292                                &spillers, (void**) &selected_spiller);
 293
 294         FIRM_DBG_REGISTER(dbg, "firm.be.spillprepare");
 295 }