gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 1989, 1992, 1997, 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 #include "hconfig.h"
  23 #include "system.h"
  24 #include "rtl.h"
  25 #include "obstack.h"
  26
  27 static struct obstack obstack;
  28 struct obstack *rtl_obstack = &obstack;
  29
  30 #define obstack_chunk_alloc xmalloc
  31 #define obstack_chunk_free free
  32
  33 /* Define this so we can link with print-rtl.o to get debug_rtx function.  */
  34 char **insn_name_ptr = 0;
  35
  36 /* While tree-walking an instruction pattern, we keep a chain
  37    of these `struct link's to record how to get down to the
  38    current position.  In each one, POS is the operand number,
  39    and if the operand is a vector VEC is the element number.
  40    VEC is -1 if the operand is not a vector.  */
  41
  42 struct link
  43 {
  44   struct link *next;
  45   int pos;
  46   int vecelt;
  47 };
  48
  49 char *xmalloc PROTO((unsigned));
  50 static void fatal PVPROTO ((char *, ...))
  51   ATTRIBUTE_PRINTF_1 ATTRIBUTE_NORETURN;
  52 void fancy_abort PROTO((void)) ATTRIBUTE_NORETURN;
  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 gen_peephole PROTO((rtx));
  66 static void match_rtx PROTO((rtx, struct link *, int));
  67 static void print_path PROTO((struct link *));
  68 static void print_code PROTO((RTX_CODE));
  69 \f
  70 static void
  71 gen_peephole (peep)
  72      rtx peep;
  73 {
  74   int ninsns = XVECLEN (peep, 0);
  75   int i;
  76
  77   n_operands = 0;
  78
  79   printf ("  insn = ins1;\n");
  80 #if 0
  81   printf ("  want_jump = 0;\n");
  82 #endif
  83
  84   for (i = 0; i < ninsns; i++)
  85     {
  86       if (i > 0)
  87         {
  88           printf ("  do { insn = NEXT_INSN (insn);\n");
  89           printf ("       if (insn == 0) goto L%d; }\n",
  90                   insn_code_number);
  91           printf ("  while (GET_CODE (insn) == NOTE\n");
  92           printf ("\t || (GET_CODE (insn) == INSN\n");
  93           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  94           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  95
  96           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  97       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  98                   insn_code_number);
  99         }
 100
 101 #if 0
 102       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
 103       printf ("    want_jump = JUMP_LABEL (insn);\n");
 104 #endif
 105
 106       printf ("  pat = PATTERN (insn);\n");
 107
 108       /* Walk the insn's pattern, remembering at all times the path
 109          down to the walking point.  */
 110
 111       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 112     }
 113
 114   /* We get this far if the pattern matches.
 115      Now test the extra condition.  */
 116
 117   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 118     printf ("  if (! (%s)) goto L%d;\n",
 119             XSTR (peep, 1), insn_code_number);
 120
 121   /* If that matches, construct new pattern and put it in the first insn.
 122      This new pattern will never be matched.
 123      It exists only so that insn-extract can get the operands back.
 124      So use a simple regular form: a PARALLEL containing a vector
 125      of all the operands.  */
 126
 127   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 128
 129 #if 0
 130   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 131   printf ("    {\n");
 132   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 133   printf ("      delete_insn (ins1);\n");
 134   printf ("      ins1 = ins2;\n");
 135   printf ("    }\n");
 136 #endif
 137
 138   /* Record this define_peephole's insn code in the insn,
 139      as if it had been recognized to match this.  */
 140   printf ("  INSN_CODE (ins1) = %d;\n",
 141           insn_code_number);
 142
 143   /* Delete the remaining insns.  */
 144   if (ninsns > 1)
 145     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 146
 147   /* See reload1.c for insertion of NOTE which guarantees that this
 148      cannot be zero.  */
 149   printf ("  return NEXT_INSN (insn);\n");
 150
 151   printf (" L%d:\n\n", insn_code_number);
 152 }
 153 \f
 154 static void
 155 match_rtx (x, path, fail_label)
 156      rtx x;
 157      struct link *path;
 158      int fail_label;
 159 {
 160   register RTX_CODE code;
 161   register int i;
 162   register int len;
 163   register char *fmt;
 164   struct link link;
 165
 166   if (x == 0)
 167     return;
 168
 169
 170   code = GET_CODE (x);
 171
 172   switch (code)
 173     {
 174     case MATCH_OPERAND:
 175       if (XINT (x, 0) > max_opno)
 176         max_opno = XINT (x, 0);
 177       if (XINT (x, 0) >= n_operands)
 178         n_operands = 1 + XINT (x, 0);
 179
 180       printf ("  x = ");
 181       print_path (path);
 182       printf (";\n");
 183
 184       printf ("  operands[%d] = x;\n", XINT (x, 0));
 185       if (XSTR (x, 1) && XSTR (x, 1)[0])
 186         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 187                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 188       return;
 189
 190     case MATCH_DUP:
 191     case MATCH_PAR_DUP:
 192       printf ("  x = ");
 193       print_path (path);
 194       printf (";\n");
 195
 196       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 197               XINT (x, 0), fail_label);
 198       return;
 199
 200     case MATCH_OP_DUP:
 201       printf ("  x = ");
 202       print_path (path);
 203       printf (";\n");
 204
 205       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 206       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 207               XINT (x, 0), fail_label);
 208       printf ("  operands[%d] = x;\n", XINT (x, 0));
 209       link.next = path;
 210       link.vecelt = -1;
 211       for (i = 0; i < XVECLEN (x, 1); i++)
 212         {
 213           link.pos = i;
 214           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 215         }
 216       return;
 217
 218     case MATCH_OPERATOR:
 219       if (XINT (x, 0) > max_opno)
 220         max_opno = XINT (x, 0);
 221       if (XINT (x, 0) >= n_operands)
 222         n_operands = 1 + XINT (x, 0);
 223
 224       printf ("  x = ");
 225       print_path (path);
 226       printf (";\n");
 227
 228       printf ("  operands[%d] = x;\n", XINT (x, 0));
 229       if (XSTR (x, 1) && XSTR (x, 1)[0])
 230         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 231                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 232       link.next = path;
 233       link.vecelt = -1;
 234       for (i = 0; i < XVECLEN (x, 2); i++)
 235         {
 236           link.pos = i;
 237           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 238         }
 239       return;
 240
 241     case MATCH_PARALLEL:
 242       if (XINT (x, 0) > max_opno)
 243         max_opno = XINT (x, 0);
 244       if (XINT (x, 0) >= n_operands)
 245         n_operands = 1 + XINT (x, 0);
 246
 247       printf ("  x = ");
 248       print_path (path);
 249       printf (";\n");
 250
 251       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 252       printf ("  operands[%d] = x;\n", XINT (x, 0));
 253       if (XSTR (x, 1) && XSTR (x, 1)[0])
 254         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 255                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 256       link.next = path;
 257       link.pos = 0;
 258       for (i = 0; i < XVECLEN (x, 2); i++)
 259         {
 260           link.vecelt = i;
 261           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 262         }
 263       return;
 264
 265     case ADDRESS:
 266       match_rtx (XEXP (x, 0), path, fail_label);
 267       return;
 268
 269     default:
 270       break;
 271     }
 272
 273   printf ("  x = ");
 274   print_path (path);
 275   printf (";\n");
 276
 277   printf ("  if (GET_CODE (x) != ");
 278   print_code (code);
 279   printf (") goto L%d;\n", fail_label);
 280
 281   if (GET_MODE (x) != VOIDmode)
 282     {
 283       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 284               GET_MODE_NAME (GET_MODE (x)), fail_label);
 285     }
 286
 287   link.next = path;
 288   link.vecelt = -1;
 289   fmt = GET_RTX_FORMAT (code);
 290   len = GET_RTX_LENGTH (code);
 291   for (i = 0; i < len; i++)
 292     {
 293       link.pos = i;
 294       if (fmt[i] == 'e' || fmt[i] == 'u')
 295         match_rtx (XEXP (x, i), &link, fail_label);
 296       else if (fmt[i] == 'E')
 297         {
 298           int j;
 299           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 300                   i, XVECLEN (x, i), fail_label);
 301           for (j = 0; j < XVECLEN (x, i); j++)
 302             {
 303               link.vecelt = j;
 304               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 305             }
 306         }
 307       else if (fmt[i] == 'i')
 308         {
 309           /* Make sure that at run time `x' is the RTX we want to test.  */
 310           if (i != 0)
 311             {
 312               printf ("  x = ");
 313               print_path (path);
 314               printf (";\n");
 315             }
 316
 317           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 318                   i, XINT (x, i), fail_label);
 319         }
 320       else if (fmt[i] == 'w')
 321         {
 322           /* Make sure that at run time `x' is the RTX we want to test.  */
 323           if (i != 0)
 324             {
 325               printf ("  x = ");
 326               print_path (path);
 327               printf (";\n");
 328             }
 329
 330           printf ("  if (XWINT (x, %d) != ", i);
 331           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 332           printf (") goto L%d;\n", fail_label);
 333         }
 334       else if (fmt[i] == 's')
 335         {
 336           /* Make sure that at run time `x' is the RTX we want to test.  */
 337           if (i != 0)
 338             {
 339               printf ("  x = ");
 340               print_path (path);
 341               printf (";\n");
 342             }
 343
 344           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 345                   i, XSTR (x, i), fail_label);
 346         }
 347     }
 348 }
 349
 350 /* Given a PATH, representing a path down the instruction's
 351    pattern from the root to a certain point, output code to
 352    evaluate to the rtx at that point.  */
 353
 354 static void
 355 print_path (path)
 356      struct link *path;
 357 {
 358   if (path == 0)
 359     printf ("pat");
 360   else if (path->vecelt >= 0)
 361     {
 362       printf ("XVECEXP (");
 363       print_path (path->next);
 364       printf (", %d, %d)", path->pos, path->vecelt);
 365     }
 366   else
 367     {
 368       printf ("XEXP (");
 369       print_path (path->next);
 370       printf (", %d)", path->pos);
 371     }
 372 }
 373 \f
 374 static void
 375 print_code (code)
 376      RTX_CODE code;
 377 {
 378   register char *p1;
 379   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 380     {
 381       if (*p1 >= 'a' && *p1 <= 'z')
 382         putchar (*p1 + 'A' - 'a');
 383       else
 384         putchar (*p1);
 385     }
 386 }
 387 \f
 388 char *
 389 xmalloc (size)
 390      unsigned size;
 391 {
 392   register char *val = (char *) malloc (size);
 393
 394   if (val == 0)
 395     fatal ("virtual memory exhausted");
 396   return val;
 397 }
 398
 399 char *
 400 xrealloc (ptr, size)
 401      char *ptr;
 402      unsigned size;
 403 {
 404   char *result = (char *) realloc (ptr, size);
 405   if (!result)
 406     fatal ("virtual memory exhausted");
 407   return result;
 408 }
 409
 410 static void
 411 fatal VPROTO ((char *format, ...))
 412 {
 413 #ifndef ANSI_PROTOTYPES
 414   char *format;
 415 #endif
 416   va_list ap;
 417
 418   VA_START (ap, format);
 419
 420 #ifndef ANSI_PROTOTYPES
 421   format = va_arg (ap, char *);
 422 #endif
 423
 424   fprintf (stderr, "genpeep: ");
 425   vfprintf (stderr, format, ap);
 426   va_end (ap);
 427   fprintf (stderr, "\n");
 428   exit (FATAL_EXIT_CODE);
 429 }
 430
 431 /* More 'friendly' abort that prints the line and file.
 432    config.h can #define abort fancy_abort if you like that sort of thing.  */
 433
 434 void
 435 fancy_abort ()
 436 {
 437   fatal ("Internal gcc abort.");
 438 }
 439 \f
 440 int
 441 main (argc, argv)
 442      int argc;
 443      char **argv;
 444 {
 445   rtx desc;
 446   FILE *infile;
 447   register int c;
 448
 449   max_opno = -1;
 450
 451   obstack_init (rtl_obstack);
 452
 453   if (argc <= 1)
 454     fatal ("No input file name.");
 455
 456   infile = fopen (argv[1], "r");
 457   if (infile == 0)
 458     {
 459       perror (argv[1]);
 460       exit (FATAL_EXIT_CODE);
 461     }
 462
 463   init_rtl ();
 464
 465   printf ("/* Generated automatically by the program `genpeep'\n\
 466 from the machine description file `md'.  */\n\n");
 467
 468   printf ("#include \"config.h\"\n");
 469   printf ("#include \"system.h\"\n");
 470   printf ("#include \"insn-config.h\"\n");
 471   printf ("#include \"rtl.h\"\n");
 472   printf ("#include \"regs.h\"\n");
 473   printf ("#include \"output.h\"\n");
 474   printf ("#include \"real.h\"\n");
 475   printf ("#include \"recog.h\"\n");
 476   printf ("#include \"except.h\"\n\n");
 477
 478   printf ("extern rtx peep_operand[];\n\n");
 479   printf ("#define operands peep_operand\n\n");
 480
 481   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 482   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 483
 484   /* Early out: no peepholes for insns followed by barriers.  */
 485   printf ("  if (NEXT_INSN (ins1)\n");
 486   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 487   printf ("    return 0;\n\n");
 488
 489   /* Read the machine description.  */
 490
 491   while (1)
 492     {
 493       c = read_skip_spaces (infile);
 494       if (c == EOF)
 495         break;
 496       ungetc (c, infile);
 497
 498       desc = read_rtx (infile);
 499       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 500         {
 501           gen_peephole (desc);
 502           insn_code_number++;
 503         }
 504       if (GET_CODE (desc) == DEFINE_INSN
 505           || GET_CODE (desc) == DEFINE_EXPAND
 506           || GET_CODE (desc) == DEFINE_SPLIT)
 507         {
 508           insn_code_number++;
 509         }
 510     }
 511
 512   printf ("  return 0;\n}\n\n");
 513
 514   if (max_opno == -1)
 515     max_opno = 1;
 516
 517   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 518
 519   fflush (stdout);
 520   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 521   /* NOTREACHED */
 522   return 0;
 523 }