gcc/reload.h

   1 /* Communication between reload.c and reload1.c.
   2    Copyright (C) 1987, 91-95, 97, 1998 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 /* If secondary reloads are the same for inputs and outputs, define those
  23    macros here.  */
  24
  25 #ifdef SECONDARY_RELOAD_CLASS
  26 #define SECONDARY_INPUT_RELOAD_CLASS(CLASS, MODE, X) \
  27   SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
  28 #define SECONDARY_OUTPUT_RELOAD_CLASS(CLASS, MODE, X) \
  29   SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
  30 #endif
  31
  32 /* If either macro is defined, show that we need secondary reloads.  */
  33 #if defined(SECONDARY_INPUT_RELOAD_CLASS) || defined(SECONDARY_OUTPUT_RELOAD_CLASS)
  34 #define HAVE_SECONDARY_RELOADS
  35 #endif
  36
  37 /* If MEMORY_MOVE_COST isn't defined, give it a default here.  */
  38 #ifndef MEMORY_MOVE_COST
  39 #ifdef HAVE_SECONDARY_RELOADS
  40 #define MEMORY_MOVE_COST(MODE,CLASS,IN) \
  41   (4 + memory_move_secondary_cost ((MODE), (CLASS), (IN)))
  42 #else
  43 #define MEMORY_MOVE_COST(MODE,CLASS,IN) 4
  44 #endif
  45 #endif
  46 extern int memory_move_secondary_cost PROTO ((enum machine_mode, enum reg_class, int));
  47
  48 /* See reload.c and reload1.c for comments on these variables.  */
  49
  50 /* Maximum number of reloads we can need.  */
  51 #define MAX_RELOADS (2 * MAX_RECOG_OPERANDS * (MAX_REGS_PER_ADDRESS + 1))
  52
  53 extern enum reg_class reload_address_base_reg_class;
  54 extern enum reg_class reload_address_index_reg_class;
  55 extern rtx reload_in[MAX_RELOADS];
  56 extern rtx reload_out[MAX_RELOADS];
  57 extern rtx reload_in_reg[MAX_RELOADS];
  58 extern rtx reload_out_reg[MAX_RELOADS];
  59 extern enum reg_class reload_reg_class[MAX_RELOADS];
  60 extern enum machine_mode reload_inmode[MAX_RELOADS];
  61 extern enum machine_mode reload_outmode[MAX_RELOADS];
  62 extern char reload_optional[MAX_RELOADS];
  63 extern char reload_nongroup[MAX_RELOADS];
  64 extern int reload_inc[MAX_RELOADS];
  65 extern int reload_opnum[MAX_RELOADS];
  66 extern int reload_secondary_p[MAX_RELOADS];
  67 extern int reload_secondary_in_reload[MAX_RELOADS];
  68 extern int reload_secondary_out_reload[MAX_RELOADS];
  69 #ifdef MAX_INSN_CODE
  70 extern enum insn_code reload_secondary_in_icode[MAX_RELOADS];
  71 extern enum insn_code reload_secondary_out_icode[MAX_RELOADS];
  72 #endif
  73 extern int n_reloads;
  74
  75 extern rtx reload_reg_rtx[MAX_RELOADS];
  76
  77 /* Encode the usage of a reload.  The following codes are supported:
  78
  79    RELOAD_FOR_INPUT             reload of an input operand
  80    RELOAD_FOR_OUTPUT            likewise, for output
  81    RELOAD_FOR_INSN              a reload that must not conflict with anything
  82                                 used in the insn, but may conflict with
  83                                 something used before or after the insn
  84    RELOAD_FOR_INPUT_ADDRESS     reload for parts of the address of an object
  85                                 that is an input reload
  86    RELOAD_FOR_INPADDR_ADDRESS   reload needed for RELOAD_FOR_INPUT_ADDRESS
  87    RELOAD_FOR_OUTPUT_ADDRESS    like RELOAD_FOR INPUT_ADDRESS, for output
  88    RELOAD_FOR_OUTADDR_ADDRESS   reload needed for RELOAD_FOR_OUTPUT_ADDRESS
  89    RELOAD_FOR_OPERAND_ADDRESS   reload for the address of a non-reloaded
  90                                 operand; these don't conflict with
  91                                 any other addresses.
  92    RELOAD_FOR_OPADDR_ADDR       reload needed for RELOAD_FOR_OPERAND_ADDRESS
  93                                 reloads; usually secondary reloads
  94    RELOAD_OTHER                 none of the above, usually multiple uses
  95    RELOAD_FOR_OTHER_ADDRESS     reload for part of the address of an input
  96                                 that is marked RELOAD_OTHER.
  97
  98    This used to be "enum reload_when_needed" but some debuggers have trouble
  99    with an enum tag and variable of the same name.  */
 100
 101 enum reload_type
 102 {
 103   RELOAD_FOR_INPUT, RELOAD_FOR_OUTPUT, RELOAD_FOR_INSN,
 104   RELOAD_FOR_INPUT_ADDRESS, RELOAD_FOR_INPADDR_ADDRESS,
 105   RELOAD_FOR_OUTPUT_ADDRESS, RELOAD_FOR_OUTADDR_ADDRESS,
 106   RELOAD_FOR_OPERAND_ADDRESS, RELOAD_FOR_OPADDR_ADDR,
 107   RELOAD_OTHER, RELOAD_FOR_OTHER_ADDRESS
 108 };
 109
 110 extern enum reload_type reload_when_needed[MAX_RELOADS];
 111
 112 extern rtx *reg_equiv_constant;
 113 extern rtx *reg_equiv_memory_loc;
 114 extern rtx *reg_equiv_address;
 115 extern rtx *reg_equiv_mem;
 116
 117 /* All the "earlyclobber" operands of the current insn
 118    are recorded here.  */
 119 extern int n_earlyclobbers;
 120 extern rtx reload_earlyclobbers[MAX_RECOG_OPERANDS];
 121
 122 /* Save the number of operands.  */
 123 extern int reload_n_operands;
 124
 125 /* First uid used by insns created by reload in this function.
 126    Used in find_equiv_reg.  */
 127 extern int reload_first_uid;
 128
 129 /* Nonzero if indirect addressing is supported when the innermost MEM is
 130    of the form (MEM (SYMBOL_REF sym)).  It is assumed that the level to
 131    which these are valid is the same as spill_indirect_levels, above.   */
 132
 133 extern char indirect_symref_ok;
 134
 135 /* Nonzero if an address (plus (reg frame_pointer) (reg ...)) is valid.  */
 136 extern char double_reg_address_ok;
 137
 138 extern int num_not_at_initial_offset;
 139
 140 #ifdef MAX_INSN_CODE
 141 /* These arrays record the insn_code of insns that may be needed to
 142    perform input and output reloads of special objects.  They provide a
 143    place to pass a scratch register.  */
 144 extern enum insn_code reload_in_optab[];
 145 extern enum insn_code reload_out_optab[];
 146 #endif
 147
 148 struct needs
 149 {
 150   /* [0] is normal, [1] is nongroup.  */
 151   short regs[2][N_REG_CLASSES];
 152   short groups[N_REG_CLASSES];
 153 };
 154
 155 #if defined SET_HARD_REG_BIT && defined CLEAR_REG_SET
 156 /* This structure describes instructions which are relevant for reload.
 157    Apart from all regular insns, this also includes CODE_LABELs, since they
 158    must be examined for register elimination.  */
 159 struct insn_chain
 160 {
 161   /* Links to the neighbour instructions.  */
 162   struct insn_chain *next, *prev;
 163
 164   /* Link through a chains set up by calculate_needs_all_insns, containing
 165      all insns that need reloading.  */
 166   struct insn_chain *next_need_reload;
 167
 168   /* The basic block this insn is in.  */
 169   int block;
 170   /* The rtx of the insn.  */
 171   rtx insn;
 172   /* Register life information: record all live hard registers, and all
 173      live pseudos that have a hard register.
 174      This information is recorded for the point immediately before the insn
 175      (in live_before), and for the point within the insn at which all
 176      outputs have just been written to (in live_after).  */
 177   regset live_before;
 178   regset live_after;
 179
 180   /* For each class, size of group of consecutive regs
 181      that is needed for the reloads of this class.  */
 182   char group_size[N_REG_CLASSES];
 183   /* For each class, the machine mode which requires consecutive
 184      groups of regs of that class.
 185      If two different modes ever require groups of one class,
 186      they must be the same size and equally restrictive for that class,
 187      otherwise we can't handle the complexity.  */
 188   enum machine_mode group_mode[N_REG_CLASSES];
 189
 190   /* Indicates if a register was counted against the need for
 191      groups.  0 means it can count against max_nongroup instead.  */
 192   HARD_REG_SET counted_for_groups;
 193
 194   /* Indicates if a register was counted against the need for
 195      non-groups.  0 means it can become part of a new group.
 196      During choose_reload_regs, 1 here means don't use this reg
 197      as part of a group, even if it seems to be otherwise ok.  */
 198   HARD_REG_SET counted_for_nongroups;
 199
 200   /* Indicates which registers have already been used for spills.  */
 201   HARD_REG_SET used_spill_regs;
 202
 203   /* Describe the needs for reload registers of this insn.  */
 204   struct needs need;
 205
 206   /* Nonzero if find_reloads said the insn requires reloading.  */
 207   unsigned int need_reload:1;
 208   /* Nonzero if eliminate_regs_in_insn said it requires eliminations.  */
 209   unsigned int need_elim:1;
 210   /* Nonzero if this insn was inserted by perform_caller_saves.  */
 211   unsigned int is_caller_save_insn:1;
 212 };
 213
 214 /* A chain of insn_chain structures to describe all non-note insns in
 215    a function.  */
 216 extern struct insn_chain *reload_insn_chain;
 217
 218 /* Allocate a new insn_chain structure.  */
 219 extern struct insn_chain *new_insn_chain        PROTO((void));
 220
 221 extern void compute_use_by_pseudos              PROTO((HARD_REG_SET *, regset));
 222 #endif
 223
 224 /* Functions from reload.c:  */
 225
 226 /* Return a memory location that will be used to copy X in mode MODE.
 227    If we haven't already made a location for this mode in this insn,
 228    call find_reloads_address on the location being returned.  */
 229 extern rtx get_secondary_mem PROTO((rtx, enum machine_mode,
 230                                     int, enum reload_type));
 231
 232 /* Clear any secondary memory locations we've made.  */
 233 extern void clear_secondary_mem PROTO((void));
 234
 235 /* Transfer all replacements that used to be in reload FROM to be in
 236    reload TO.  */
 237 extern void transfer_replacements PROTO((int, int));
 238
 239 /* IN_RTX is the value loaded by a reload that we now decided to inherit,
 240    or a subpart of it.  If we have any replacements registered for IN_RTX,
 241    chancel the reloads that were supposed to load them.
 242    Return non-zero if we chanceled any reloads.  */
 243 extern int remove_address_replacements PROTO((rtx in_rtx));
 244
 245 /* Like rtx_equal_p except that it allows a REG and a SUBREG to match
 246    if they are the same hard reg, and has special hacks for
 247    autoincrement and autodecrement.  */
 248 extern int operands_match_p PROTO((rtx, rtx));
 249
 250 /* Return the number of times character C occurs in string S.  */
 251 extern int n_occurrences PROTO((int, char *));
 252
 253 /* Return 1 if altering OP will not modify the value of CLOBBER. */
 254 extern int safe_from_earlyclobber PROTO((rtx, rtx));
 255
 256 /* Search the body of INSN for values that need reloading and record them
 257    with push_reload.  REPLACE nonzero means record also where the values occur
 258    so that subst_reloads can be used.  */
 259 extern int find_reloads PROTO((rtx, int, int, int, short *));
 260
 261 /* Compute the sum of X and Y, making canonicalizations assumed in an
 262    address, namely: sum constant integers, surround the sum of two
 263    constants with a CONST, put the constant as the second operand, and
 264    group the constant on the outermost sum.  */
 265 extern rtx form_sum PROTO((rtx, rtx));
 266
 267 /* Substitute into the current INSN the registers into which we have reloaded
 268    the things that need reloading.  */
 269 extern void subst_reloads PROTO((void));
 270
 271 /* Make a copy of any replacements being done into X and move those copies
 272    to locations in Y, a copy of X.  We only look at the highest level of
 273    the RTL.  */
 274 extern void copy_replacements PROTO((rtx, rtx));
 275
 276 /* Change any replacements being done to *X to be done to *Y */
 277 extern void move_replacements PROTO((rtx *x, rtx *y));
 278
 279 /* If LOC was scheduled to be replaced by something, return the replacement.
 280    Otherwise, return *LOC.  */
 281 extern rtx find_replacement PROTO((rtx *));
 282
 283 /* Return nonzero if register in range [REGNO, ENDREGNO)
 284    appears either explicitly or implicitly in X
 285    other than being stored into.  */
 286 extern int refers_to_regno_for_reload_p PROTO((int, int, rtx, rtx *));
 287
 288 /* Nonzero if modifying X will affect IN.  */
 289 extern int reg_overlap_mentioned_for_reload_p PROTO((rtx, rtx));
 290
 291 /* Return nonzero if anything in X contains a MEM.  Look also for pseudo
 292    registers.  */
 293 extern int refers_to_mem_for_reload_p PROTO((rtx));
 294
 295 /* Check the insns before INSN to see if there is a suitable register
 296    containing the same value as GOAL.  */
 297 extern rtx find_equiv_reg PROTO((rtx, rtx, enum reg_class, int, short *,
 298                                  int, enum machine_mode));
 299
 300 /* Return 1 if register REGNO is the subject of a clobber in insn INSN.  */
 301 extern int regno_clobbered_p PROTO((int, rtx));
 302
 303 /* Functions in reload1.c:  */
 304
 305 extern int reloads_conflict             PROTO ((int, int));
 306
 307 int count_occurrences            PROTO((rtx, rtx));
 308
 309 /* Initialize the reload pass once per compilation.  */
 310 extern void init_reload PROTO((void));
 311
 312 /* The reload pass itself.  */
 313 extern int reload PROTO((rtx, int, FILE *));
 314
 315 /* Mark the slots in regs_ever_live for the hard regs
 316    used by pseudo-reg number REGNO.  */
 317 extern void mark_home_live PROTO((int));
 318
 319 /* Scan X and replace any eliminable registers (such as fp) with a
 320    replacement (such as sp), plus an offset.  */
 321 extern rtx eliminate_regs PROTO((rtx, enum machine_mode, rtx));
 322
 323 /* Emit code to perform a reload from IN (which may be a reload register) to
 324    OUT (which may also be a reload register).  IN or OUT is from operand
 325    OPNUM with reload type TYPE.  */
 326 extern rtx gen_reload PROTO((rtx, rtx, int, enum reload_type));
 327
 328 /* Deallocate the reload register used by reload number R.  */
 329 extern void deallocate_reload_reg PROTO((int r));
 330
 331 /* Functions in caller-save.c:  */
 332
 333 /* Initialize for caller-save.  */
 334 extern void init_caller_save PROTO((void));
 335
 336 /* Initialize save areas by showing that we haven't allocated any yet.  */
 337 extern void init_save_areas PROTO((void));
 338
 339 /* Allocate save areas for any hard registers that might need saving.  */
 340 extern void setup_save_areas PROTO((void));
 341
 342 /* Find the places where hard regs are live across calls and save them.  */
 343 extern void save_call_clobbered_regs PROTO((void));