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