gcc/reload.h

   1 /* Communication between reload.c and reload1.c.
   2    Copyright (C) 1987, 1991, 1992, 1993, 1994 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, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20
  21 /* If secondary reloads are the same for inputs and outputs, define those
  22    macros here.  */
  23
  24 #ifdef SECONDARY_RELOAD_CLASS
  25 #define SECONDARY_INPUT_RELOAD_CLASS(CLASS, MODE, X) \
  26   SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
  27 #define SECONDARY_OUTPUT_RELOAD_CLASS(CLASS, MODE, X) \
  28   SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
  29 #endif
  30
  31 /* If either macro is defined, show that we need secondary reloads.  */
  32 #if defined(SECONDARY_INPUT_RELOAD_CLASS) || defined(SECONDARY_OUTPUT_RELOAD_CLASS)
  33 #define HAVE_SECONDARY_RELOADS
  34 #endif
  35
  36 /* See reload.c and reload1.c for comments on these variables.  */
  37
  38 /* Maximum number of reloads we can need.  */
  39 #define MAX_RELOADS (2 * MAX_RECOG_OPERANDS * (MAX_REGS_PER_ADDRESS + 1))
  40
  41 extern rtx reload_in[MAX_RELOADS];
  42 extern rtx reload_out[MAX_RELOADS];
  43 extern rtx reload_in_reg[MAX_RELOADS];
  44 extern enum reg_class reload_reg_class[MAX_RELOADS];
  45 extern enum machine_mode reload_inmode[MAX_RELOADS];
  46 extern enum machine_mode reload_outmode[MAX_RELOADS];
  47 extern char reload_optional[MAX_RELOADS];
  48 extern int reload_inc[MAX_RELOADS];
  49 extern int reload_opnum[MAX_RELOADS];
  50 extern int reload_secondary_p[MAX_RELOADS];
  51 extern int reload_secondary_in_reload[MAX_RELOADS];
  52 extern int reload_secondary_out_reload[MAX_RELOADS];
  53 #ifdef MAX_INSN_CODE
  54 extern enum insn_code reload_secondary_in_icode[MAX_RELOADS];
  55 extern enum insn_code reload_secondary_out_icode[MAX_RELOADS];
  56 #endif
  57 extern int n_reloads;
  58
  59 extern rtx reload_reg_rtx[MAX_RELOADS];
  60
  61 /* Encode the usage of a reload.  The following codes are supported:
  62
  63    RELOAD_FOR_INPUT             reload of an input operand
  64    RELOAD_FOR_OUTPUT            likewise, for output
  65    RELOAD_FOR_INSN              a reload that must not conflict with anything
  66                                 used in the insn, but may conflict with
  67                                 something used before or after the insn
  68    RELOAD_FOR_INPUT_ADDRESS     reload for parts of the address of an object
  69                                 that is an input reload
  70    RELOAD_FOR_OUTPUT_ADDRESS    likewise, for output reload
  71    RELOAD_FOR_OPERAND_ADDRESS   reload for the address of a non-reloaded
  72                                 operand; these don't conflict with
  73                                 any other addresses.
  74    RELOAD_FOR_OPADDR_ADDR       reload needed for RELOAD_FOR_OPERAND_ADDRESS
  75                                 reloads; usually secondary reloads
  76    RELOAD_OTHER                 none of the above, usually multiple uses
  77    RELOAD_FOR_OTHER_ADDRESS     reload for part of the address of an input
  78                                 that is marked RELOAD_OTHER.
  79
  80    This used to be "enum reload_when_needed" but some debuggers have trouble
  81    with an enum tag and variable of the same name.  */
  82
  83 enum reload_type
  84 {
  85   RELOAD_FOR_INPUT, RELOAD_FOR_OUTPUT, RELOAD_FOR_INSN,
  86   RELOAD_FOR_INPUT_ADDRESS, RELOAD_FOR_OUTPUT_ADDRESS,
  87   RELOAD_FOR_OPERAND_ADDRESS, RELOAD_FOR_OPADDR_ADDR,
  88   RELOAD_OTHER, RELOAD_FOR_OTHER_ADDRESS
  89 };
  90
  91 extern enum reload_type reload_when_needed[MAX_RELOADS];
  92
  93 extern rtx *reg_equiv_constant;
  94 extern rtx *reg_equiv_memory_loc;
  95 extern rtx *reg_equiv_address;
  96 extern rtx *reg_equiv_mem;
  97
  98 /* All the "earlyclobber" operands of the current insn
  99    are recorded here.  */
 100 extern int n_earlyclobbers;
 101 extern rtx reload_earlyclobbers[MAX_RECOG_OPERANDS];
 102
 103 /* Save the number of operands.  */
 104 extern int reload_n_operands;
 105
 106 /* First uid used by insns created by reload in this function.
 107    Used in find_equiv_reg.  */
 108 extern int reload_first_uid;
 109
 110 /* Nonzero if indirect addressing is supported when the innermost MEM is
 111    of the form (MEM (SYMBOL_REF sym)).  It is assumed that the level to
 112    which these are valid is the same as spill_indirect_levels, above.   */
 113
 114 extern char indirect_symref_ok;
 115
 116 /* Nonzero if an address (plus (reg frame_pointer) (reg ...)) is valid.  */
 117 extern char double_reg_address_ok;
 118
 119 #ifdef MAX_INSN_CODE
 120 /* These arrays record the insn_code of insns that may be needed to
 121    perform input and output reloads of special objects.  They provide a
 122    place to pass a scratch register.  */
 123 extern enum insn_code reload_in_optab[];
 124 extern enum insn_code reload_out_optab[];
 125 #endif
 126
 127 /* Functions from reload.c:  */
 128
 129 /* Return a memory location that will be used to copy X in mode MODE.
 130    If we haven't already made a location for this mode in this insn,
 131    call find_reloads_address on the location being returned.  */
 132 extern rtx get_secondary_mem PROTO((rtx, enum machine_mode,
 133                                     int, enum reload_type));
 134
 135 /* Clear any secondary memory locations we've made.  */
 136 extern void clear_secondary_mem PROTO((void));
 137
 138 /* Transfer all replacements that used to be in reload FROM to be in
 139    reload TO.  */
 140 extern void transfer_replacements PROTO((int, int));
 141
 142 /* Return 1 if ADDR is a valid memory address for mode MODE,
 143    and check that each pseudo reg has the proper kind of
 144    hard reg.  */
 145 extern int strict_memory_address_p PROTO((enum machine_mode, rtx));
 146
 147 /* Like rtx_equal_p except that it allows a REG and a SUBREG to match
 148    if they are the same hard reg, and has special hacks for
 149    autoincrement and autodecrement.  */
 150 extern int operands_match_p PROTO((rtx, rtx));
 151
 152 /* Return the number of times character C occurs in string S.  */
 153 extern int n_occurrences PROTO((int, char *));
 154
 155 /* Return 1 if altering OP will not modify the value of CLOBBER. */
 156 extern int safe_from_earlyclobber PROTO((rtx, rtx));
 157
 158 /* Search the body of INSN for values that need reloading and record them
 159    with push_reload.  REPLACE nonzero means record also where the values occur
 160    so that subst_reloads can be used.  */
 161 extern void find_reloads PROTO((rtx, int, int, int, short *));
 162
 163 /* Compute the sum of X and Y, making canonicalizations assumed in an
 164    address, namely: sum constant integers, surround the sum of two
 165    constants with a CONST, put the constant as the second operand, and
 166    group the constant on the outermost sum.  */
 167 extern rtx form_sum PROTO((rtx, rtx));
 168
 169 /* Substitute into the current INSN the registers into which we have reloaded
 170    the things that need reloading.  */
 171 extern void subst_reloads PROTO((void));
 172
 173 /* Make a copy of any replacements being done into X and move those copies
 174    to locations in Y, a copy of X.  We only look at the highest level of
 175    the RTL.  */
 176 extern void copy_replacements PROTO((rtx, rtx));
 177
 178 /* If LOC was scheduled to be replaced by something, return the replacement.
 179    Otherwise, return *LOC.  */
 180 extern rtx find_replacement PROTO((rtx *));
 181
 182 /* Return nonzero if register in range [REGNO, ENDREGNO)
 183    appears either explicitly or implicitly in X
 184    other than being stored into.  */
 185 extern int refers_to_regno_for_reload_p PROTO((int, int, rtx, rtx *));
 186
 187 /* Nonzero if modifying X will affect IN.  */
 188 extern int reg_overlap_mentioned_for_reload_p PROTO((rtx, rtx));
 189
 190 /* Return nonzero if anything in X contains a MEM.  Look also for pseudo
 191    registers.  */
 192 extern int refers_to_mem_for_reload_p PROTO((rtx));
 193
 194 /* Check the insns before INSN to see if there is a suitable register
 195    containing the same value as GOAL.  */
 196 extern rtx find_equiv_reg PROTO((rtx, rtx, enum reg_class, int, short *,
 197                                  int, enum machine_mode));
 198
 199 /* Return 1 if register REGNO is the subject of a clobber in insn INSN.  */
 200 extern int regno_clobbered_p PROTO((int, rtx));
 201
 202
 203 /* Functions in reload1.c:  */
 204
 205 /* Initialize the reload pass once per compilation.  */
 206 extern void init_reload PROTO((void));
 207
 208 /* The reload pass itself.  */
 209 extern int reload STDIO_PROTO((rtx, int, FILE *));
 210
 211 /* Mark the slots in regs_ever_live for the hard regs
 212    used by pseudo-reg number REGNO.  */
 213 extern void mark_home_live PROTO((int));
 214
 215 /* Scan X and replace any eliminable registers (such as fp) with a
 216    replacement (such as sp), plus an offset.  */
 217 extern rtx eliminate_regs PROTO((rtx, enum machine_mode, rtx));
 218
 219 /* Emit code to perform a reload from IN (which may be a reload register) to
 220    OUT (which may also be a reload register).  IN or OUT is from operand
 221    OPNUM with reload type TYPE.  */
 222 extern rtx gen_reload PROTO((rtx, rtx, int, enum reload_type));
 223
 224 /* Functions in caller-save.c:  */
 225
 226 /* Initialize for caller-save.  */
 227 extern void init_caller_save PROTO((void));
 228
 229 /* Initialize save areas by showing that we haven't allocated any yet.  */
 230 extern void init_save_areas PROTO((void));
 231
 232 /* Allocate save areas for any hard registers that might need saving.  */
 233 extern int setup_save_areas PROTO((int *));
 234
 235 /* Find the places where hard regs are live across calls and save them.  */
 236 extern void save_call_clobbered_regs PROTO((enum machine_mode));