gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 89, 92, 97, 98, 1999 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 void fatal PVPROTO ((const char *, ...))
  50   ATTRIBUTE_PRINTF_1 ATTRIBUTE_NORETURN;
  51 void fancy_abort PROTO((void)) ATTRIBUTE_NORETURN;
  52
  53 static int max_opno;
  54
  55 /* Number of operands used in current peephole definition.  */
  56
  57 static int n_operands;
  58
  59 /* Peephole optimizations get insn codes just like insn patterns.
  60    Count them so we know the code of the define_peephole we are handling.  */
  61
  62 static int insn_code_number = 0;
  63
  64 static void gen_peephole PROTO((rtx));
  65 static void match_rtx PROTO((rtx, struct link *, int));
  66 static void print_path PROTO((struct link *));
  67 static void print_code PROTO((RTX_CODE));
  68 \f
  69 static void
  70 gen_peephole (peep)
  71      rtx peep;
  72 {
  73   int ninsns = XVECLEN (peep, 0);
  74   int i;
  75
  76   n_operands = 0;
  77
  78   printf ("  insn = ins1;\n");
  79 #if 0
  80   printf ("  want_jump = 0;\n");
  81 #endif
  82
  83   for (i = 0; i < ninsns; i++)
  84     {
  85       if (i > 0)
  86         {
  87           printf ("  do { insn = NEXT_INSN (insn);\n");
  88           printf ("       if (insn == 0) goto L%d; }\n",
  89                   insn_code_number);
  90           printf ("  while (GET_CODE (insn) == NOTE\n");
  91           printf ("\t || (GET_CODE (insn) == INSN\n");
  92           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  93           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  94
  95           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  96       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  97                   insn_code_number);
  98         }
  99
 100 #if 0
 101       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
 102       printf ("    want_jump = JUMP_LABEL (insn);\n");
 103 #endif
 104
 105       printf ("  pat = PATTERN (insn);\n");
 106
 107       /* Walk the insn's pattern, remembering at all times the path
 108          down to the walking point.  */
 109
 110       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 111     }
 112
 113   /* We get this far if the pattern matches.
 114      Now test the extra condition.  */
 115
 116   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 117     printf ("  if (! (%s)) goto L%d;\n",
 118             XSTR (peep, 1), insn_code_number);
 119
 120   /* If that matches, construct new pattern and put it in the first insn.
 121      This new pattern will never be matched.
 122      It exists only so that insn-extract can get the operands back.
 123      So use a simple regular form: a PARALLEL containing a vector
 124      of all the operands.  */
 125
 126   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 127
 128 #if 0
 129   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 130   printf ("    {\n");
 131   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 132   printf ("      delete_insn (ins1);\n");
 133   printf ("      ins1 = ins2;\n");
 134   printf ("    }\n");
 135 #endif
 136
 137   /* Record this define_peephole's insn code in the insn,
 138      as if it had been recognized to match this.  */
 139   printf ("  INSN_CODE (ins1) = %d;\n",
 140           insn_code_number);
 141
 142   /* Delete the remaining insns.  */
 143   if (ninsns > 1)
 144     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 145
 146   /* See reload1.c for insertion of NOTE which guarantees that this
 147      cannot be zero.  */
 148   printf ("  return NEXT_INSN (insn);\n");
 149
 150   printf (" L%d:\n\n", insn_code_number);
 151 }
 152 \f
 153 static void
 154 match_rtx (x, path, fail_label)
 155      rtx x;
 156      struct link *path;
 157      int fail_label;
 158 {
 159   register RTX_CODE code;
 160   register int i;
 161   register int len;
 162   register const char *fmt;
 163   struct link link;
 164
 165   if (x == 0)
 166     return;
 167
 168
 169   code = GET_CODE (x);
 170
 171   switch (code)
 172     {
 173     case MATCH_OPERAND:
 174       if (XINT (x, 0) > max_opno)
 175         max_opno = XINT (x, 0);
 176       if (XINT (x, 0) >= n_operands)
 177         n_operands = 1 + XINT (x, 0);
 178
 179       printf ("  x = ");
 180       print_path (path);
 181       printf (";\n");
 182
 183       printf ("  operands[%d] = x;\n", XINT (x, 0));
 184       if (XSTR (x, 1) && XSTR (x, 1)[0])
 185         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 186                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 187       return;
 188
 189     case MATCH_DUP:
 190     case MATCH_PAR_DUP:
 191       printf ("  x = ");
 192       print_path (path);
 193       printf (";\n");
 194
 195       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 196               XINT (x, 0), fail_label);
 197       return;
 198
 199     case MATCH_OP_DUP:
 200       printf ("  x = ");
 201       print_path (path);
 202       printf (";\n");
 203
 204       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 205       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 206               XINT (x, 0), fail_label);
 207       printf ("  operands[%d] = x;\n", XINT (x, 0));
 208       link.next = path;
 209       link.vecelt = -1;
 210       for (i = 0; i < XVECLEN (x, 1); i++)
 211         {
 212           link.pos = i;
 213           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 214         }
 215       return;
 216
 217     case MATCH_OPERATOR:
 218       if (XINT (x, 0) > max_opno)
 219         max_opno = XINT (x, 0);
 220       if (XINT (x, 0) >= n_operands)
 221         n_operands = 1 + XINT (x, 0);
 222
 223       printf ("  x = ");
 224       print_path (path);
 225       printf (";\n");
 226
 227       printf ("  operands[%d] = x;\n", XINT (x, 0));
 228       if (XSTR (x, 1) && XSTR (x, 1)[0])
 229         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 230                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 231       link.next = path;
 232       link.vecelt = -1;
 233       for (i = 0; i < XVECLEN (x, 2); i++)
 234         {
 235           link.pos = i;
 236           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 237         }
 238       return;
 239
 240     case MATCH_PARALLEL:
 241       if (XINT (x, 0) > max_opno)
 242         max_opno = XINT (x, 0);
 243       if (XINT (x, 0) >= n_operands)
 244         n_operands = 1 + XINT (x, 0);
 245
 246       printf ("  x = ");
 247       print_path (path);
 248       printf (";\n");
 249
 250       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 251       printf ("  operands[%d] = x;\n", XINT (x, 0));
 252       if (XSTR (x, 1) && XSTR (x, 1)[0])
 253         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 254                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 255       link.next = path;
 256       link.pos = 0;
 257       for (i = 0; i < XVECLEN (x, 2); i++)
 258         {
 259           link.vecelt = i;
 260           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 261         }
 262       return;
 263
 264     case ADDRESS:
 265       match_rtx (XEXP (x, 0), path, fail_label);
 266       return;
 267
 268     default:
 269       break;
 270     }
 271
 272   printf ("  x = ");
 273   print_path (path);
 274   printf (";\n");
 275
 276   printf ("  if (GET_CODE (x) != ");
 277   print_code (code);
 278   printf (") goto L%d;\n", fail_label);
 279
 280   if (GET_MODE (x) != VOIDmode)
 281     {
 282       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 283               GET_MODE_NAME (GET_MODE (x)), fail_label);
 284     }
 285
 286   link.next = path;
 287   link.vecelt = -1;
 288   fmt = GET_RTX_FORMAT (code);
 289   len = GET_RTX_LENGTH (code);
 290   for (i = 0; i < len; i++)
 291     {
 292       link.pos = i;
 293       if (fmt[i] == 'e' || fmt[i] == 'u')
 294         match_rtx (XEXP (x, i), &link, fail_label);
 295       else if (fmt[i] == 'E')
 296         {
 297           int j;
 298           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 299                   i, XVECLEN (x, i), fail_label);
 300           for (j = 0; j < XVECLEN (x, i); j++)
 301             {
 302               link.vecelt = j;
 303               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 304             }
 305         }
 306       else if (fmt[i] == 'i')
 307         {
 308           /* Make sure that at run time `x' is the RTX we want to test.  */
 309           if (i != 0)
 310             {
 311               printf ("  x = ");
 312               print_path (path);
 313               printf (";\n");
 314             }
 315
 316           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 317                   i, XINT (x, i), fail_label);
 318         }
 319       else if (fmt[i] == 'w')
 320         {
 321           /* Make sure that at run time `x' is the RTX we want to test.  */
 322           if (i != 0)
 323             {
 324               printf ("  x = ");
 325               print_path (path);
 326               printf (";\n");
 327             }
 328
 329           printf ("  if (XWINT (x, %d) != ", i);
 330           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 331           printf (") goto L%d;\n", fail_label);
 332         }
 333       else if (fmt[i] == 's')
 334         {
 335           /* Make sure that at run time `x' is the RTX we want to test.  */
 336           if (i != 0)
 337             {
 338               printf ("  x = ");
 339               print_path (path);
 340               printf (";\n");
 341             }
 342
 343           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 344                   i, XSTR (x, i), fail_label);
 345         }
 346     }
 347 }
 348
 349 /* Given a PATH, representing a path down the instruction's
 350    pattern from the root to a certain point, output code to
 351    evaluate to the rtx at that point.  */
 352
 353 static void
 354 print_path (path)
 355      struct link *path;
 356 {
 357   if (path == 0)
 358     printf ("pat");
 359   else if (path->vecelt >= 0)
 360     {
 361       printf ("XVECEXP (");
 362       print_path (path->next);
 363       printf (", %d, %d)", path->pos, path->vecelt);
 364     }
 365   else
 366     {
 367       printf ("XEXP (");
 368       print_path (path->next);
 369       printf (", %d)", path->pos);
 370     }
 371 }
 372 \f
 373 static void
 374 print_code (code)
 375      RTX_CODE code;
 376 {
 377   register const char *p1;
 378   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 379     {
 380       if (*p1 >= 'a' && *p1 <= 'z')
 381         putchar (*p1 + 'A' - 'a');
 382       else
 383         putchar (*p1);
 384     }
 385 }
 386 \f
 387 PTR
 388 xmalloc (size)
 389   size_t size;
 390 {
 391   register PTR val = (PTR) malloc (size);
 392
 393   if (val == 0)
 394     fatal ("virtual memory exhausted");
 395   return val;
 396 }
 397
 398 PTR
 399 xrealloc (old, size)
 400   PTR old;
 401   size_t size;
 402 {
 403   register PTR ptr;
 404   if (old)
 405     ptr = (PTR) realloc (old, size);
 406   else
 407     ptr = (PTR) malloc (size);
 408   if (!ptr)
 409     fatal ("virtual memory exhausted");
 410   return ptr;
 411 }
 412
 413 void
 414 fatal VPROTO ((const char *format, ...))
 415 {
 416 #ifndef ANSI_PROTOTYPES
 417   const char *format;
 418 #endif
 419   va_list ap;
 420
 421   VA_START (ap, format);
 422
 423 #ifndef ANSI_PROTOTYPES
 424   format = va_arg (ap, const char *);
 425 #endif
 426
 427   fprintf (stderr, "genpeep: ");
 428   vfprintf (stderr, format, ap);
 429   va_end (ap);
 430   fprintf (stderr, "\n");
 431   exit (FATAL_EXIT_CODE);
 432 }
 433
 434 /* More 'friendly' abort that prints the line and file.
 435    config.h can #define abort fancy_abort if you like that sort of thing.  */
 436
 437 void
 438 fancy_abort ()
 439 {
 440   fatal ("Internal gcc abort.");
 441 }
 442 \f
 443 int
 444 main (argc, argv)
 445      int argc;
 446      char **argv;
 447 {
 448   rtx desc;
 449   FILE *infile;
 450   register int c;
 451
 452   max_opno = -1;
 453
 454   obstack_init (rtl_obstack);
 455
 456   if (argc <= 1)
 457     fatal ("No input file name.");
 458
 459   infile = fopen (argv[1], "r");
 460   if (infile == 0)
 461     {
 462       perror (argv[1]);
 463       exit (FATAL_EXIT_CODE);
 464     }
 465
 466   init_rtl ();
 467
 468   printf ("/* Generated automatically by the program `genpeep'\n\
 469 from the machine description file `md'.  */\n\n");
 470
 471   printf ("#include \"config.h\"\n");
 472   printf ("#include \"system.h\"\n");
 473   printf ("#include \"insn-config.h\"\n");
 474   printf ("#include \"rtl.h\"\n");
 475   printf ("#include \"regs.h\"\n");
 476   printf ("#include \"output.h\"\n");
 477   printf ("#include \"real.h\"\n");
 478   printf ("#include \"recog.h\"\n");
 479   printf ("#include \"except.h\"\n\n");
 480   printf ("#include \"function.h\"\n\n");
 481
 482   printf ("extern rtx peep_operand[];\n\n");
 483   printf ("#define operands peep_operand\n\n");
 484
 485   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 486   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 487
 488   /* Early out: no peepholes for insns followed by barriers.  */
 489   printf ("  if (NEXT_INSN (ins1)\n");
 490   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 491   printf ("    return 0;\n\n");
 492
 493   /* Read the machine description.  */
 494
 495   while (1)
 496     {
 497       c = read_skip_spaces (infile);
 498       if (c == EOF)
 499         break;
 500       ungetc (c, infile);
 501
 502       desc = read_rtx (infile);
 503       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 504         {
 505           gen_peephole (desc);
 506           insn_code_number++;
 507         }
 508       if (GET_CODE (desc) == DEFINE_INSN
 509           || GET_CODE (desc) == DEFINE_EXPAND
 510           || GET_CODE (desc) == DEFINE_SPLIT)
 511         {
 512           insn_code_number++;
 513         }
 514     }
 515
 516   printf ("  return 0;\n}\n\n");
 517
 518   if (max_opno == -1)
 519     max_opno = 1;
 520
 521   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 522
 523   fflush (stdout);
 524   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 525   /* NOTREACHED */
 526   return 0;
 527 }