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