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
  52 static int max_opno;
  53
  54 /* Number of operands used in current peephole definition.  */
  55
  56 static int n_operands;
  57
  58 /* Peephole optimizations get insn codes just like insn patterns.
  59    Count them so we know the code of the define_peephole we are handling.  */
  60
  61 static int insn_code_number = 0;
  62
  63 static void gen_peephole PROTO((rtx));
  64 static void match_rtx PROTO((rtx, struct link *, int));
  65 static void print_path PROTO((struct link *));
  66 static void print_code PROTO((RTX_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), NULL_PTR, 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 const 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     case MATCH_PAR_DUP:
 190       printf ("  x = ");
 191       print_path (path);
 192       printf (";\n");
 193
 194       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 195               XINT (x, 0), fail_label);
 196       return;
 197
 198     case MATCH_OP_DUP:
 199       printf ("  x = ");
 200       print_path (path);
 201       printf (";\n");
 202
 203       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 204       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 205               XINT (x, 0), fail_label);
 206       printf ("  operands[%d] = x;\n", XINT (x, 0));
 207       link.next = path;
 208       link.vecelt = -1;
 209       for (i = 0; i < XVECLEN (x, 1); i++)
 210         {
 211           link.pos = i;
 212           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 213         }
 214       return;
 215
 216     case MATCH_OPERATOR:
 217       if (XINT (x, 0) > max_opno)
 218         max_opno = XINT (x, 0);
 219       if (XINT (x, 0) >= n_operands)
 220         n_operands = 1 + XINT (x, 0);
 221
 222       printf ("  x = ");
 223       print_path (path);
 224       printf (";\n");
 225
 226       printf ("  operands[%d] = x;\n", XINT (x, 0));
 227       if (XSTR (x, 1) && XSTR (x, 1)[0])
 228         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 229                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 230       link.next = path;
 231       link.vecelt = -1;
 232       for (i = 0; i < XVECLEN (x, 2); i++)
 233         {
 234           link.pos = i;
 235           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 236         }
 237       return;
 238
 239     case MATCH_PARALLEL:
 240       if (XINT (x, 0) > max_opno)
 241         max_opno = XINT (x, 0);
 242       if (XINT (x, 0) >= n_operands)
 243         n_operands = 1 + XINT (x, 0);
 244
 245       printf ("  x = ");
 246       print_path (path);
 247       printf (";\n");
 248
 249       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 250       printf ("  operands[%d] = x;\n", XINT (x, 0));
 251       if (XSTR (x, 1) && XSTR (x, 1)[0])
 252         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 253                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 254       link.next = path;
 255       link.pos = 0;
 256       for (i = 0; i < XVECLEN (x, 2); i++)
 257         {
 258           link.vecelt = i;
 259           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 260         }
 261       return;
 262
 263     case ADDRESS:
 264       match_rtx (XEXP (x, 0), path, fail_label);
 265       return;
 266
 267     default:
 268       break;
 269     }
 270
 271   printf ("  x = ");
 272   print_path (path);
 273   printf (";\n");
 274
 275   printf ("  if (GET_CODE (x) != ");
 276   print_code (code);
 277   printf (") goto L%d;\n", fail_label);
 278
 279   if (GET_MODE (x) != VOIDmode)
 280     {
 281       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 282               GET_MODE_NAME (GET_MODE (x)), fail_label);
 283     }
 284
 285   link.next = path;
 286   link.vecelt = -1;
 287   fmt = GET_RTX_FORMAT (code);
 288   len = GET_RTX_LENGTH (code);
 289   for (i = 0; i < len; i++)
 290     {
 291       link.pos = i;
 292       if (fmt[i] == 'e' || fmt[i] == 'u')
 293         match_rtx (XEXP (x, i), &link, fail_label);
 294       else if (fmt[i] == 'E')
 295         {
 296           int j;
 297           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 298                   i, XVECLEN (x, i), fail_label);
 299           for (j = 0; j < XVECLEN (x, i); j++)
 300             {
 301               link.vecelt = j;
 302               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 303             }
 304         }
 305       else if (fmt[i] == 'i')
 306         {
 307           /* Make sure that at run time `x' is the RTX we want to test.  */
 308           if (i != 0)
 309             {
 310               printf ("  x = ");
 311               print_path (path);
 312               printf (";\n");
 313             }
 314
 315           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 316                   i, XINT (x, i), fail_label);
 317         }
 318       else if (fmt[i] == 'w')
 319         {
 320           /* Make sure that at run time `x' is the RTX we want to test.  */
 321           if (i != 0)
 322             {
 323               printf ("  x = ");
 324               print_path (path);
 325               printf (";\n");
 326             }
 327
 328           printf ("  if (XWINT (x, %d) != ", i);
 329           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 330           printf (") goto L%d;\n", fail_label);
 331         }
 332       else if (fmt[i] == 's')
 333         {
 334           /* Make sure that at run time `x' is the RTX we want to test.  */
 335           if (i != 0)
 336             {
 337               printf ("  x = ");
 338               print_path (path);
 339               printf (";\n");
 340             }
 341
 342           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 343                   i, XSTR (x, i), fail_label);
 344         }
 345     }
 346 }
 347
 348 /* Given a PATH, representing a path down the instruction's
 349    pattern from the root to a certain point, output code to
 350    evaluate to the rtx at that point.  */
 351
 352 static void
 353 print_path (path)
 354      struct link *path;
 355 {
 356   if (path == 0)
 357     printf ("pat");
 358   else if (path->vecelt >= 0)
 359     {
 360       printf ("XVECEXP (");
 361       print_path (path->next);
 362       printf (", %d, %d)", path->pos, path->vecelt);
 363     }
 364   else
 365     {
 366       printf ("XEXP (");
 367       print_path (path->next);
 368       printf (", %d)", path->pos);
 369     }
 370 }
 371 \f
 372 static void
 373 print_code (code)
 374      RTX_CODE code;
 375 {
 376   register const char *p1;
 377   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 378     {
 379       if (*p1 >= 'a' && *p1 <= 'z')
 380         putchar (*p1 + 'A' - 'a');
 381       else
 382         putchar (*p1);
 383     }
 384 }
 385 \f
 386 PTR
 387 xmalloc (size)
 388   size_t size;
 389 {
 390   register PTR val = (PTR) malloc (size);
 391
 392   if (val == 0)
 393     fatal ("virtual memory exhausted");
 394   return val;
 395 }
 396
 397 PTR
 398 xrealloc (old, size)
 399   PTR old;
 400   size_t size;
 401 {
 402   register PTR ptr;
 403   if (old)
 404     ptr = (PTR) realloc (old, size);
 405   else
 406     ptr = (PTR) malloc (size);
 407   if (!ptr)
 408     fatal ("virtual memory exhausted");
 409   return ptr;
 410 }
 411
 412 void
 413 fatal VPROTO ((const char *format, ...))
 414 {
 415 #ifndef ANSI_PROTOTYPES
 416   const char *format;
 417 #endif
 418   va_list ap;
 419
 420   VA_START (ap, format);
 421
 422 #ifndef ANSI_PROTOTYPES
 423   format = va_arg (ap, const char *);
 424 #endif
 425
 426   fprintf (stderr, "genpeep: ");
 427   vfprintf (stderr, format, ap);
 428   va_end (ap);
 429   fprintf (stderr, "\n");
 430   exit (FATAL_EXIT_CODE);
 431 }
 432
 433 int
 434 main (argc, argv)
 435      int argc;
 436      char **argv;
 437 {
 438   rtx desc;
 439   FILE *infile;
 440   register int c;
 441
 442   max_opno = -1;
 443
 444   obstack_init (rtl_obstack);
 445
 446   if (argc <= 1)
 447     fatal ("No input file name.");
 448
 449   infile = fopen (argv[1], "r");
 450   if (infile == 0)
 451     {
 452       perror (argv[1]);
 453       exit (FATAL_EXIT_CODE);
 454     }
 455
 456   init_rtl ();
 457
 458   printf ("/* Generated automatically by the program `genpeep'\n\
 459 from the machine description file `md'.  */\n\n");
 460
 461   printf ("#include \"config.h\"\n");
 462   printf ("#include \"system.h\"\n");
 463   printf ("#include \"insn-config.h\"\n");
 464   printf ("#include \"rtl.h\"\n");
 465   printf ("#include \"regs.h\"\n");
 466   printf ("#include \"output.h\"\n");
 467   printf ("#include \"real.h\"\n");
 468   printf ("#include \"recog.h\"\n");
 469   printf ("#include \"except.h\"\n\n");
 470   printf ("#include \"function.h\"\n\n");
 471
 472   printf ("extern rtx peep_operand[];\n\n");
 473   printf ("#define operands peep_operand\n\n");
 474
 475   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 476   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 477
 478   /* Early out: no peepholes for insns followed by barriers.  */
 479   printf ("  if (NEXT_INSN (ins1)\n");
 480   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 481   printf ("    return 0;\n\n");
 482
 483   /* Read the machine description.  */
 484
 485   while (1)
 486     {
 487       c = read_skip_spaces (infile);
 488       if (c == EOF)
 489         break;
 490       ungetc (c, infile);
 491
 492       desc = read_rtx (infile);
 493       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 494         {
 495           gen_peephole (desc);
 496           insn_code_number++;
 497         }
 498       if (GET_CODE (desc) == DEFINE_INSN
 499           || GET_CODE (desc) == DEFINE_EXPAND
 500           || GET_CODE (desc) == DEFINE_SPLIT)
 501         {
 502           insn_code_number++;
 503         }
 504     }
 505
 506   printf ("  return 0;\n}\n\n");
 507
 508   if (max_opno == -1)
 509     max_opno = 1;
 510
 511   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 512
 513   fflush (stdout);
 514   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 515   /* NOTREACHED */
 516   return 0;
 517 }