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