gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 1989, 1992 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 #include <stdio.h>
  22 #include "config.h"
  23 #include "rtl.h"
  24 #include "obstack.h"
  25
  26 static struct obstack obstack;
  27 struct obstack *rtl_obstack = &obstack;
  28
  29 #define obstack_chunk_alloc xmalloc
  30 #define obstack_chunk_free free
  31
  32 extern void free ();
  33 extern rtx read_rtx ();
  34
  35 /* While tree-walking an instruction pattern, we keep a chain
  36    of these `struct link's to record how to get down to the
  37    current position.  In each one, POS is the operand number,
  38    and if the operand is a vector VEC is the element number.
  39    VEC is -1 if the operand is not a vector.  */
  40
  41 struct link
  42 {
  43   struct link *next;
  44   int pos;
  45   int vecelt;
  46 };
  47
  48 char *xmalloc ();
  49 static void match_rtx ();
  50 static void gen_exp ();
  51 static void fatal ();
  52 void fancy_abort ();
  53
  54 static int max_opno;
  55
  56 /* Number of operands used in current peephole definition.  */
  57
  58 static int n_operands;
  59
  60 /* Peephole optimizations get insn codes just like insn patterns.
  61    Count them so we know the code of the define_peephole we are handling.  */
  62
  63 static int insn_code_number = 0;
  64
  65 static void print_path ();
  66 static void print_code ();
  67 \f
  68 static void
  69 gen_peephole (peep)
  70      rtx peep;
  71 {
  72   int ninsns = XVECLEN (peep, 0);
  73   int i;
  74
  75   n_operands = 0;
  76
  77   printf ("  insn = ins1;\n");
  78 #if 0
  79   printf ("  want_jump = 0;\n");
  80 #endif
  81
  82   for (i = 0; i < ninsns; i++)
  83     {
  84       if (i > 0)
  85         {
  86           printf ("  do { insn = NEXT_INSN (insn);\n");
  87           printf ("       if (insn == 0) goto L%d; }\n",
  88                   insn_code_number);
  89           printf ("  while (GET_CODE (insn) == NOTE\n");
  90           printf ("\t || (GET_CODE (insn) == INSN\n");
  91           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  92           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  93
  94           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  95       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  96                   insn_code_number);
  97         }
  98
  99 #if 0
 100       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
 101       printf ("    want_jump = JUMP_LABEL (insn);\n");
 102 #endif
 103
 104       printf ("  pat = PATTERN (insn);\n");
 105
 106       /* Walk the insn's pattern, remembering at all times the path
 107          down to the walking point.  */
 108
 109       match_rtx (XVECEXP (peep, 0, i), 0, insn_code_number);
 110     }
 111
 112   /* We get this far if the pattern matches.
 113      Now test the extra condition.  */
 114
 115   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 116     printf ("  if (! (%s)) goto L%d;\n",
 117             XSTR (peep, 1), insn_code_number);
 118
 119   /* If that matches, construct new pattern and put it in the first insn.
 120      This new pattern will never be matched.
 121      It exists only so that insn-extract can get the operands back.
 122      So use a simple regular form: a PARALLEL containing a vector
 123      of all the operands.  */
 124
 125   printf ("  PATTERN (ins1) = gen_rtx (PARALLEL, VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 126
 127 #if 0
 128   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 129   printf ("    {\n");
 130   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 131   printf ("      delete_insn (ins1);\n");
 132   printf ("      ins1 = ins2;\n");
 133   printf ("    }\n");
 134 #endif
 135
 136   /* Record this define_peephole's insn code in the insn,
 137      as if it had been recognized to match this.  */
 138   printf ("  INSN_CODE (ins1) = %d;\n",
 139           insn_code_number);
 140
 141   /* Delete the remaining insns.  */
 142   if (ninsns > 1)
 143     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 144
 145   /* See reload1.c for insertion of NOTE which guarantees that this
 146      cannot be zero.  */
 147   printf ("  return NEXT_INSN (insn);\n");
 148
 149   printf (" L%d:\n\n", insn_code_number);
 150 }
 151 \f
 152 static void
 153 match_rtx (x, path, fail_label)
 154      rtx x;
 155      struct link *path;
 156      int fail_label;
 157 {
 158   register RTX_CODE code;
 159   register int i;
 160   register int len;
 161   register char *fmt;
 162   struct link link;
 163
 164   if (x == 0)
 165     return;
 166
 167
 168   code = GET_CODE (x);
 169
 170   switch (code)
 171     {
 172     case MATCH_OPERAND:
 173       if (XINT (x, 0) > max_opno)
 174         max_opno = XINT (x, 0);
 175       if (XINT (x, 0) >= n_operands)
 176         n_operands = 1 + XINT (x, 0);
 177
 178       printf ("  x = ");
 179       print_path (path);
 180       printf (";\n");
 181
 182       printf ("  operands[%d] = x;\n", XINT (x, 0));
 183       if (XSTR (x, 1) && XSTR (x, 1)[0])
 184         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 185                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 186       return;
 187
 188     case MATCH_DUP:
 189       printf ("  x = ");
 190       print_path (path);
 191       printf (";\n");
 192
 193       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 194               XINT (x, 0), fail_label);
 195       return;
 196
 197     case MATCH_OP_DUP:
 198       printf ("  x = ");
 199       print_path (path);
 200       printf (";\n");
 201
 202       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 203       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 204               XINT (x, 0), fail_label);
 205       printf ("  operands[%d] = x;\n", XINT (x, 0));
 206       link.next = path;
 207       link.vecelt = -1;
 208       for (i = 0; i < XVECLEN (x, 1); i++)
 209         {
 210           link.pos = i;
 211           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 212         }
 213       return;
 214
 215     case MATCH_OPERATOR:
 216       if (XINT (x, 0) > max_opno)
 217         max_opno = XINT (x, 0);
 218       if (XINT (x, 0) >= n_operands)
 219         n_operands = 1 + XINT (x, 0);
 220
 221       printf ("  x = ");
 222       print_path (path);
 223       printf (";\n");
 224
 225       printf ("  operands[%d] = x;\n", XINT (x, 0));
 226       if (XSTR (x, 1) && XSTR (x, 1)[0])
 227         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 228                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 229       link.next = path;
 230       link.vecelt = -1;
 231       for (i = 0; i < XVECLEN (x, 2); i++)
 232         {
 233           link.pos = i;
 234           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 235         }
 236       return;
 237
 238     case MATCH_PARALLEL:
 239       if (XINT (x, 0) > max_opno)
 240         max_opno = XINT (x, 0);
 241       if (XINT (x, 0) >= n_operands)
 242         n_operands = 1 + XINT (x, 0);
 243
 244       printf ("  x = ");
 245       print_path (path);
 246       printf (";\n");
 247
 248       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 249       printf ("  operands[%d] = x;\n", XINT (x, 0));
 250       if (XSTR (x, 1) && XSTR (x, 1)[0])
 251         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 252                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 253       link.next = path;
 254       link.pos = 0;
 255       for (i = 0; i < XVECLEN (x, 2); i++)
 256         {
 257           link.vecelt = i;
 258           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 259         }
 260       return;
 261
 262     case ADDRESS:
 263       match_rtx (XEXP (x, 0), path, fail_label);
 264       return;
 265     }
 266
 267   printf ("  x = ");
 268   print_path (path);
 269   printf (";\n");
 270
 271   printf ("  if (GET_CODE (x) != ");
 272   print_code (code);
 273   printf (") goto L%d;\n", fail_label);
 274
 275   if (GET_MODE (x) != VOIDmode)
 276     {
 277       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 278               GET_MODE_NAME (GET_MODE (x)), fail_label);
 279     }
 280
 281   link.next = path;
 282   link.vecelt = -1;
 283   fmt = GET_RTX_FORMAT (code);
 284   len = GET_RTX_LENGTH (code);
 285   for (i = 0; i < len; i++)
 286     {
 287       link.pos = i;
 288       if (fmt[i] == 'e' || fmt[i] == 'u')
 289         match_rtx (XEXP (x, i), &link, fail_label);
 290       else if (fmt[i] == 'E')
 291         {
 292           int j;
 293           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 294                   i, XVECLEN (x, i), fail_label);
 295           for (j = 0; j < XVECLEN (x, i); j++)
 296             {
 297               link.vecelt = j;
 298               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 299             }
 300         }
 301       else if (fmt[i] == 'i')
 302         {
 303           /* Make sure that at run time `x' is the RTX we want to test.  */
 304           if (i != 0)
 305             {
 306               printf ("  x = ");
 307               print_path (path);
 308               printf (";\n");
 309             }
 310
 311           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 312                   i, XINT (x, i), fail_label);
 313         }
 314       else if (fmt[i] == 's')
 315         {
 316           /* Make sure that at run time `x' is the RTX we want to test.  */
 317           if (i != 0)
 318             {
 319               printf ("  x = ");
 320               print_path (path);
 321               printf (";\n");
 322             }
 323
 324           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 325                   i, XSTR (x, i), fail_label);
 326         }
 327     }
 328 }
 329
 330 /* Given a PATH, representing a path down the instruction's
 331    pattern from the root to a certain point, output code to
 332    evaluate to the rtx at that point.  */
 333
 334 static void
 335 print_path (path)
 336      struct link *path;
 337 {
 338   if (path == 0)
 339     printf ("pat");
 340   else if (path->vecelt >= 0)
 341     {
 342       printf ("XVECEXP (");
 343       print_path (path->next);
 344       printf (", %d, %d)", path->pos, path->vecelt);
 345     }
 346   else
 347     {
 348       printf ("XEXP (");
 349       print_path (path->next);
 350       printf (", %d)", path->pos);
 351     }
 352 }
 353 \f
 354 static void
 355 print_code (code)
 356      RTX_CODE code;
 357 {
 358   register char *p1;
 359   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 360     {
 361       if (*p1 >= 'a' && *p1 <= 'z')
 362         putchar (*p1 + 'A' - 'a');
 363       else
 364         putchar (*p1);
 365     }
 366 }
 367 \f
 368 char *
 369 xmalloc (size)
 370      unsigned size;
 371 {
 372   register char *val = (char *) malloc (size);
 373
 374   if (val == 0)
 375     fatal ("virtual memory exhausted");
 376   return val;
 377 }
 378
 379 char *
 380 xrealloc (ptr, size)
 381      char *ptr;
 382      unsigned size;
 383 {
 384   char *result = (char *) realloc (ptr, size);
 385   if (!result)
 386     fatal ("virtual memory exhausted");
 387   return result;
 388 }
 389
 390 static void
 391 fatal (s, a1, a2)
 392      char *s;
 393 {
 394   fprintf (stderr, "genpeep: ");
 395   fprintf (stderr, s, a1, a2);
 396   fprintf (stderr, "\n");
 397   exit (FATAL_EXIT_CODE);
 398 }
 399
 400 /* More 'friendly' abort that prints the line and file.
 401    config.h can #define abort fancy_abort if you like that sort of thing.  */
 402
 403 void
 404 fancy_abort ()
 405 {
 406   fatal ("Internal gcc abort.");
 407 }
 408 \f
 409 int
 410 main (argc, argv)
 411      int argc;
 412      char **argv;
 413 {
 414   rtx desc;
 415   FILE *infile;
 416   register int c;
 417
 418   max_opno = -1;
 419
 420   obstack_init (rtl_obstack);
 421
 422   if (argc <= 1)
 423     fatal ("No input file name.");
 424
 425   infile = fopen (argv[1], "r");
 426   if (infile == 0)
 427     {
 428       perror (argv[1]);
 429       exit (FATAL_EXIT_CODE);
 430     }
 431
 432   init_rtl ();
 433
 434   printf ("/* Generated automatically by the program `genpeep'\n\
 435 from the machine description file `md'.  */\n\n");
 436
 437   printf ("#include \"config.h\"\n");
 438   printf ("#include \"rtl.h\"\n");
 439   printf ("#include \"regs.h\"\n");
 440   printf ("#include \"output.h\"\n");
 441   printf ("#include \"real.h\"\n\n");
 442
 443   printf ("extern rtx peep_operand[];\n\n");
 444   printf ("#define operands peep_operand\n\n");
 445
 446   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 447   printf ("  rtx insn, x, pat;\n");
 448   printf ("  int i;\n\n");
 449
 450   /* Early out: no peepholes for insns followed by barriers.  */
 451   printf ("  if (NEXT_INSN (ins1)\n");
 452   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 453   printf ("    return 0;\n\n");
 454
 455   /* Read the machine description.  */
 456
 457   while (1)
 458     {
 459       c = read_skip_spaces (infile);
 460       if (c == EOF)
 461         break;
 462       ungetc (c, infile);
 463
 464       desc = read_rtx (infile);
 465       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 466         {
 467           gen_peephole (desc);
 468           insn_code_number++;
 469         }
 470       if (GET_CODE (desc) == DEFINE_INSN
 471           || GET_CODE (desc) == DEFINE_EXPAND
 472           || GET_CODE (desc) == DEFINE_SPLIT)
 473         {
 474           insn_code_number++;
 475         }
 476     }
 477
 478   printf ("  return 0;\n}\n\n");
 479
 480   if (max_opno == -1)
 481     max_opno = 1;
 482
 483   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 484
 485   fflush (stdout);
 486   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 487   /* NOTREACHED */
 488   return 0;
 489 }