gcc/lra-int.h

   1 /* Local Register Allocator (LRA) intercommunication header file.
   2    Copyright (C) 2010-2014 Free Software Foundation, Inc.
   3    Contributed by Vladimir Makarov <vmakarov@redhat.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "lra.h"
  22 #include "bitmap.h"
  23 #include "recog.h"
  24 #include "insn-attr.h"
  25 #include "insn-codes.h"
  26 #include "insn-config.h"
  27 #include "regs.h"
  28
  29 #define lra_assert(c) gcc_checking_assert (c)
  30
  31 /* The parameter used to prevent infinite reloading for an insn.  Each
  32    insn operands might require a reload and, if it is a memory, its
  33    base and index registers might require a reload too.  */
  34 #define LRA_MAX_INSN_RELOADS (MAX_RECOG_OPERANDS * 3)
  35
  36 typedef struct lra_live_range *lra_live_range_t;
  37
  38 /* The structure describes program points where a given pseudo lives.
  39    The live ranges can be used to find conflicts with other pseudos.
  40    If the live ranges of two pseudos are intersected, the pseudos are
  41    in conflict.  */
  42 struct lra_live_range
  43 {
  44   /* Pseudo regno whose live range is described by given
  45      structure.  */
  46   int regno;
  47   /* Program point range.  */
  48   int start, finish;
  49   /* Next structure describing program points where the pseudo
  50      lives.  */
  51   lra_live_range_t next;
  52   /* Pointer to structures with the same start.  */
  53   lra_live_range_t start_next;
  54 };
  55
  56 typedef struct lra_copy *lra_copy_t;
  57
  58 /* Copy between pseudos which affects assigning hard registers.  */
  59 struct lra_copy
  60 {
  61   /* True if regno1 is the destination of the copy.  */
  62   bool regno1_dest_p;
  63   /* Execution frequency of the copy.  */
  64   int freq;
  65   /* Pseudos connected by the copy.  REGNO1 < REGNO2.  */
  66   int regno1, regno2;
  67   /* Next copy with correspondingly REGNO1 and REGNO2.  */
  68   lra_copy_t regno1_next, regno2_next;
  69 };
  70
  71 /* Common info about a register (pseudo or hard register).  */
  72 struct lra_reg
  73 {
  74   /* Bitmap of UIDs of insns (including debug insns) referring the
  75      reg.  */
  76   bitmap_head insn_bitmap;
  77   /* The following fields are defined only for pseudos.  */
  78   /* Hard registers with which the pseudo conflicts.  */
  79   HARD_REG_SET conflict_hard_regs;
  80   /* Call used registers with which the pseudo conflicts, taking into account
  81      the registers used by functions called from calls which cross the
  82      pseudo.  */
  83   HARD_REG_SET actual_call_used_reg_set;
  84   /* We assign hard registers to reload pseudos which can occur in few
  85      places.  So two hard register preferences are enough for them.
  86      The following fields define the preferred hard registers.  If
  87      there are no such hard registers the first field value is
  88      negative.  If there is only one preferred hard register, the 2nd
  89      field is negative.  */
  90   int preferred_hard_regno1, preferred_hard_regno2;
  91   /* Profits to use the corresponding preferred hard registers.  If
  92      the both hard registers defined, the first hard register has not
  93      less profit than the second one.  */
  94   int preferred_hard_regno_profit1, preferred_hard_regno_profit2;
  95 #ifdef STACK_REGS
  96   /* True if the pseudo should not be assigned to a stack register.  */
  97   bool no_stack_p;
  98 #endif
  99 #ifdef ENABLE_CHECKING
 100   /* True if the pseudo crosses a call.  It is setup in lra-lives.c
 101      and used to check that the pseudo crossing a call did not get a
 102      call used hard register.  */
 103   bool call_p;
 104 #endif
 105   /* Number of references and execution frequencies of the register in
 106      *non-debug* insns.  */
 107   int nrefs, freq;
 108   int last_reload;
 109   /* Regno used to undo the inheritance.  It can be non-zero only
 110      between couple of inheritance and undo inheritance passes.  */
 111   int restore_regno;
 112   /* Value holding by register.  If the pseudos have the same value
 113      they do not conflict.  */
 114   int val;
 115   /* Offset from relative eliminate register to pesudo reg.  */
 116   int offset;
 117   /* These members are set up in lra-lives.c and updated in
 118      lra-coalesce.c.  */
 119   /* The biggest size mode in which each pseudo reg is referred in
 120      whole function (possibly via subreg).  */
 121   enum machine_mode biggest_mode;
 122   /* Live ranges of the pseudo.  */
 123   lra_live_range_t live_ranges;
 124   /* This member is set up in lra-lives.c for subsequent
 125      assignments.  */
 126   lra_copy_t copies;
 127 };
 128
 129 /* References to the common info about each register.  */
 130 extern struct lra_reg *lra_reg_info;
 131
 132 /* Static info about each insn operand (common for all insns with the
 133    same ICODE).  Warning: if the structure definition is changed, the
 134    initializer for debug_operand_data in lra.c should be changed
 135    too.  */
 136 struct lra_operand_data
 137 {
 138   /* The machine description constraint string of the operand.  */
 139   const char *constraint;
 140   /* It is taken only from machine description (which is different
 141      from recog_data.operand_mode) and can be of VOIDmode.  */
 142   ENUM_BITFIELD(machine_mode) mode : 16;
 143   /* The type of the operand (in/out/inout).  */
 144   ENUM_BITFIELD (op_type) type : 8;
 145   /* Through if accessed through STRICT_LOW.  */
 146   unsigned int strict_low : 1;
 147   /* True if the operand is an operator.  */
 148   unsigned int is_operator : 1;
 149   /* True if there is an early clobber alternative for this operand.
 150      This field is set up every time when corresponding
 151      operand_alternative in lra_static_insn_data is set up.  */
 152   unsigned int early_clobber : 1;
 153   /* True if the operand is an address.  */
 154   unsigned int is_address : 1;
 155 };
 156
 157 /* Info about register occurrence in an insn.  */
 158 struct lra_insn_reg
 159 {
 160   /* The biggest mode through which the insn refers to the register
 161      occurrence (remember the register can be accessed through a
 162      subreg in the insn).  */
 163   ENUM_BITFIELD(machine_mode) biggest_mode : 16;
 164   /* The type of the corresponding operand which is the register.  */
 165   ENUM_BITFIELD (op_type) type : 8;
 166   /* True if the reg is accessed through a subreg and the subreg is
 167      just a part of the register.  */
 168   unsigned int subreg_p : 1;
 169   /* True if there is an early clobber alternative for this
 170      operand.  */
 171   unsigned int early_clobber : 1;
 172   /* The corresponding regno of the register.  */
 173   int regno;
 174   /* Next reg info of the same insn.  */
 175   struct lra_insn_reg *next;
 176 };
 177
 178 /* Static part (common info for insns with the same ICODE) of LRA
 179    internal insn info. It exists in at most one exemplar for each
 180    non-negative ICODE. There is only one exception. Each asm insn has
 181    own structure.  Warning: if the structure definition is changed,
 182    the initializer for debug_insn_static_data in lra.c should be
 183    changed too.  */
 184 struct lra_static_insn_data
 185 {
 186   /* Static info about each insn operand.  */
 187   struct lra_operand_data *operand;
 188   /* Each duplication refers to the number of the corresponding
 189      operand which is duplicated.  */
 190   int *dup_num;
 191   /* The number of an operand marked as commutative, -1 otherwise.  */
 192   int commutative;
 193   /* Number of operands, duplications, and alternatives of the
 194      insn.  */
 195   char n_operands;
 196   char n_dups;
 197   char n_alternatives;
 198   /* Insns in machine description (or clobbers in asm) may contain
 199      explicit hard regs which are not operands.  The following list
 200      describes such hard registers.  */
 201   struct lra_insn_reg *hard_regs;
 202   /* Array [n_alternatives][n_operand] of static constraint info for
 203      given operand in given alternative.  This info can be changed if
 204      the target reg info is changed.  */
 205   const struct operand_alternative *operand_alternative;
 206 };
 207
 208 /* LRA internal info about an insn (LRA internal insn
 209    representation).  */
 210 struct lra_insn_recog_data
 211 {
 212   /* The insn code.  */
 213   int icode;
 214   /* The alternative should be used for the insn, -1 if invalid, or we
 215      should try to use any alternative, or the insn is a debug
 216      insn.  */
 217   int used_insn_alternative;
 218   /* SP offset before the insn relative to one at the func start.  */
 219   HOST_WIDE_INT sp_offset;
 220   /* The insn itself.  */
 221   rtx_insn *insn;
 222   /* Common data for insns with the same ICODE.  Asm insns (their
 223      ICODE is negative) do not share such structures.  */
 224   struct lra_static_insn_data *insn_static_data;
 225   /* Two arrays of size correspondingly equal to the operand and the
 226      duplication numbers: */
 227   rtx **operand_loc; /* The operand locations, NULL if no operands.  */
 228   rtx **dup_loc; /* The dup locations, NULL if no dups.  */
 229   /* Number of hard registers implicitly used in given call insn.  The
 230      value can be NULL or points to array of the hard register numbers
 231      ending with a negative value.  */
 232   int *arg_hard_regs;
 233   /* Alternative enabled for the insn.  NULL for debug insns.  */
 234   alternative_mask enabled_alternatives;
 235   /* The following member value is always NULL for a debug insn.  */
 236   struct lra_insn_reg *regs;
 237 };
 238
 239 typedef struct lra_insn_recog_data *lra_insn_recog_data_t;
 240
 241 /* Whether the clobber is used temporary in LRA.  */
 242 #define LRA_TEMP_CLOBBER_P(x) \
 243   (RTL_FLAG_CHECK1 ("TEMP_CLOBBER_P", (x), CLOBBER)->unchanging)
 244
 245 /* Cost factor for each additional reload and maximal cost reject for
 246    insn reloads.  One might ask about such strange numbers.  Their
 247    values occurred historically from former reload pass.  */
 248 #define LRA_LOSER_COST_FACTOR 6
 249 #define LRA_MAX_REJECT 600
 250
 251 /* Maximum allowed number of constraint pass iterations after the last
 252    spill pass.  It is for preventing LRA cycling in a bug case.  */
 253 #define LRA_MAX_CONSTRAINT_ITERATION_NUMBER 30
 254
 255 /* The maximal number of inheritance/split passes in LRA.  It should
 256    be more 1 in order to perform caller saves transformations and much
 257    less MAX_CONSTRAINT_ITERATION_NUMBER to prevent LRA to do as many
 258    as permitted constraint passes in some complicated cases.  The
 259    first inheritance/split pass has a biggest impact on generated code
 260    quality.  Each subsequent affects generated code in less degree.
 261    For example, the 3rd pass does not change generated SPEC2000 code
 262    at all on x86-64.  */
 263 #define LRA_MAX_INHERITANCE_PASSES 2
 264
 265 #if LRA_MAX_INHERITANCE_PASSES <= 0 \
 266     || LRA_MAX_INHERITANCE_PASSES >= LRA_MAX_CONSTRAINT_ITERATION_NUMBER - 8
 267 #error wrong LRA_MAX_INHERITANCE_PASSES value
 268 #endif
 269
 270 /* lra.c: */
 271
 272 extern FILE *lra_dump_file;
 273
 274 extern bool lra_reg_spill_p;
 275
 276 extern HARD_REG_SET lra_no_alloc_regs;
 277
 278 extern int lra_insn_recog_data_len;
 279 extern lra_insn_recog_data_t *lra_insn_recog_data;
 280
 281 extern int lra_curr_reload_num;
 282
 283 extern void lra_push_insn (rtx_insn *);
 284 extern void lra_push_insn_by_uid (unsigned int);
 285 extern void lra_push_insn_and_update_insn_regno_info (rtx_insn *);
 286 extern rtx_insn *lra_pop_insn (void);
 287 extern unsigned int lra_insn_stack_length (void);
 288
 289 extern rtx lra_create_new_reg_with_unique_value (enum machine_mode, rtx,
 290                                                  enum reg_class, const char *);
 291 extern void lra_set_regno_unique_value (int);
 292 extern void lra_invalidate_insn_data (rtx_insn *);
 293 extern void lra_set_insn_deleted (rtx_insn *);
 294 extern void lra_delete_dead_insn (rtx_insn *);
 295 extern void lra_emit_add (rtx, rtx, rtx);
 296 extern void lra_emit_move (rtx, rtx);
 297 extern void lra_update_dups (lra_insn_recog_data_t, signed char *);
 298
 299 extern void lra_process_new_insns (rtx_insn *, rtx_insn *, rtx_insn *,
 300                                    const char *);
 301
 302 extern lra_insn_recog_data_t lra_set_insn_recog_data (rtx_insn *);
 303 extern lra_insn_recog_data_t lra_update_insn_recog_data (rtx_insn *);
 304 extern void lra_set_used_insn_alternative (rtx_insn *, int);
 305 extern void lra_set_used_insn_alternative_by_uid (int, int);
 306
 307 extern void lra_invalidate_insn_regno_info (rtx_insn *);
 308 extern void lra_update_insn_regno_info (rtx_insn *);
 309 extern struct lra_insn_reg *lra_get_insn_regs (int);
 310
 311 extern void lra_free_copies (void);
 312 extern void lra_create_copy (int, int, int);
 313 extern lra_copy_t lra_get_copy (int);
 314 extern bool lra_former_scratch_p (int);
 315 extern bool lra_former_scratch_operand_p (rtx_insn *, int);
 316
 317 extern int lra_new_regno_start;
 318 extern int lra_constraint_new_regno_start;
 319 extern bitmap_head lra_inheritance_pseudos;
 320 extern bitmap_head lra_split_regs;
 321 extern bitmap_head lra_subreg_reload_pseudos;
 322 extern bitmap_head lra_optional_reload_pseudos;
 323 extern int lra_constraint_new_insn_uid_start;
 324
 325 /* lra-constraints.c: */
 326
 327 extern void lra_init_equiv (void);
 328 extern int lra_constraint_offset (int, enum machine_mode);
 329
 330 extern int lra_constraint_iter;
 331 extern int lra_constraint_iter_after_spill;
 332 extern bool lra_risky_transformations_p;
 333 extern int lra_inheritance_iter;
 334 extern int lra_undo_inheritance_iter;
 335 extern bool lra_constraints (bool);
 336 extern void lra_constraints_init (void);
 337 extern void lra_constraints_finish (void);
 338 extern void lra_inheritance (void);
 339 extern bool lra_undo_inheritance (void);
 340
 341 /* lra-lives.c: */
 342
 343 extern int lra_live_max_point;
 344 extern int *lra_point_freq;
 345
 346 extern int lra_hard_reg_usage[FIRST_PSEUDO_REGISTER];
 347
 348 extern int lra_live_range_iter;
 349 extern void lra_create_live_ranges (bool);
 350 extern lra_live_range_t lra_copy_live_range_list (lra_live_range_t);
 351 extern lra_live_range_t lra_merge_live_ranges (lra_live_range_t,
 352                                                lra_live_range_t);
 353 extern bool lra_intersected_live_ranges_p (lra_live_range_t,
 354                                            lra_live_range_t);
 355 extern void lra_print_live_range_list (FILE *, lra_live_range_t);
 356 extern void debug (lra_live_range &ref);
 357 extern void debug (lra_live_range *ptr);
 358 extern void lra_debug_live_range_list (lra_live_range_t);
 359 extern void lra_debug_pseudo_live_ranges (int);
 360 extern void lra_debug_live_ranges (void);
 361 extern void lra_clear_live_ranges (void);
 362 extern void lra_live_ranges_init (void);
 363 extern void lra_live_ranges_finish (void);
 364 extern void lra_setup_reload_pseudo_preferenced_hard_reg (int, int, int);
 365
 366 /* lra-assigns.c: */
 367
 368 extern void lra_setup_reg_renumber (int, int, bool);
 369 extern bool lra_assign (void);
 370
 371
 372 /* lra-coalesce.c: */
 373
 374 extern int lra_coalesce_iter;
 375 extern bool lra_coalesce (void);
 376
 377 /* lra-spills.c:  */
 378
 379 extern bool lra_need_for_spills_p (void);
 380 extern void lra_spill (void);
 381 extern void lra_final_code_change (void);
 382
 383
 384 /* lra-elimination.c: */
 385
 386 extern void lra_debug_elim_table (void);
 387 extern int lra_get_elimination_hard_regno (int);
 388 extern rtx lra_eliminate_regs_1 (rtx_insn *, rtx, enum machine_mode, bool,
 389                                  bool, bool);
 390 extern void lra_eliminate (bool, bool);
 391
 392 extern void lra_eliminate_reg_if_possible (rtx *);
 393
 394 \f
 395
 396 /* Return the hard register which given pseudo REGNO assigned to.
 397    Negative value means that the register got memory or we don't know
 398    allocation yet.  */
 399 static inline int
 400 lra_get_regno_hard_regno (int regno)
 401 {
 402   resize_reg_info ();
 403   return reg_renumber[regno];
 404 }
 405
 406 /* Change class of pseudo REGNO to NEW_CLASS.  Print info about it
 407    using TITLE.  Output a new line if NL_P.  */
 408 static void inline
 409 lra_change_class (int regno, enum reg_class new_class,
 410                   const char *title, bool nl_p)
 411 {
 412   lra_assert (regno >= FIRST_PSEUDO_REGISTER);
 413   if (lra_dump_file != NULL)
 414     fprintf (lra_dump_file, "%s class %s for r%d",
 415              title, reg_class_names[new_class], regno);
 416   setup_reg_classes (regno, new_class, NO_REGS, new_class);
 417   if (lra_dump_file != NULL && nl_p)
 418     fprintf (lra_dump_file, "\n");
 419 }
 420
 421 /* Update insn operands which are duplication of NOP operand.  The
 422    insn is represented by its LRA internal representation ID.  */
 423 static inline void
 424 lra_update_dup (lra_insn_recog_data_t id, int nop)
 425 {
 426   int i;
 427   struct lra_static_insn_data *static_id = id->insn_static_data;
 428
 429   for (i = 0; i < static_id->n_dups; i++)
 430     if (static_id->dup_num[i] == nop)
 431       *id->dup_loc[i] = *id->operand_loc[nop];
 432 }
 433
 434 /* Process operator duplications in insn with ID.  We do it after the
 435    operands processing.  Generally speaking, we could do this probably
 436    simultaneously with operands processing because a common practice
 437    is to enumerate the operators after their operands.  */
 438 static inline void
 439 lra_update_operator_dups (lra_insn_recog_data_t id)
 440 {
 441   int i;
 442   struct lra_static_insn_data *static_id = id->insn_static_data;
 443
 444   for (i = 0; i < static_id->n_dups; i++)
 445     {
 446       int ndup = static_id->dup_num[i];
 447
 448       if (static_id->operand[ndup].is_operator)
 449         *id->dup_loc[i] = *id->operand_loc[ndup];
 450     }
 451 }
 452
 453 /* Return info about INSN.  Set up the info if it is not done yet.  */
 454 static inline lra_insn_recog_data_t
 455 lra_get_insn_recog_data (rtx_insn *insn)
 456 {
 457   lra_insn_recog_data_t data;
 458   unsigned int uid = INSN_UID (insn);
 459
 460   if (lra_insn_recog_data_len > (int) uid
 461       && (data = lra_insn_recog_data[uid]) != NULL)
 462     {
 463       /* Check that we did not change insn without updating the insn
 464          info.  */
 465       lra_assert (data->insn == insn
 466                   && (INSN_CODE (insn) < 0
 467                       || data->icode == INSN_CODE (insn)));
 468       return data;
 469     }
 470   return lra_set_insn_recog_data (insn);
 471 }
 472
 473 /* Update offset from pseudos with VAL by INCR.  */
 474 static inline void
 475 lra_update_reg_val_offset (int val, int incr)
 476 {
 477   int i;
 478
 479   for (i = FIRST_PSEUDO_REGISTER; i < max_reg_num (); i++)
 480     {
 481       if (lra_reg_info[i].val == val)
 482         lra_reg_info[i].offset += incr;
 483     }
 484 }
 485
 486 /* Return true if register content is equal to VAL with OFFSET.  */
 487 static inline bool
 488 lra_reg_val_equal_p (int regno, int val, int offset)
 489 {
 490   if (lra_reg_info[regno].val == val
 491       && lra_reg_info[regno].offset == offset)
 492     return true;
 493
 494   return false;
 495 }
 496
 497 /* Assign value of register FROM to TO.  */
 498 static inline void
 499 lra_assign_reg_val (int from, int to)
 500 {
 501   lra_reg_info[to].val = lra_reg_info[from].val;
 502   lra_reg_info[to].offset = lra_reg_info[from].offset;
 503 }