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 <stdio.h>
  23 #include "hconfig.h"
  24 #include "rtl.h"
  25 #include "obstack.h"
  26
  27 #ifdef HAVE_STDLIB_H
  28 #include <stdlib.h>
  29 #endif
  30
  31 static struct obstack obstack;
  32 struct obstack *rtl_obstack = &obstack;
  33
  34 #define obstack_chunk_alloc xmalloc
  35 #define obstack_chunk_free free
  36
  37 #ifdef NEED_DECLARATION_FREE
  38 extern void free ();
  39 #endif
  40 extern rtx read_rtx ();
  41
  42 /* While tree-walking an instruction pattern, we keep a chain
  43    of these `struct link's to record how to get down to the
  44    current position.  In each one, POS is the operand number,
  45    and if the operand is a vector VEC is the element number.
  46    VEC is -1 if the operand is not a vector.  */
  47
  48 struct link
  49 {
  50   struct link *next;
  51   int pos;
  52   int vecelt;
  53 };
  54
  55 char *xmalloc ();
  56 static void match_rtx ();
  57 static void fatal ();
  58 void fancy_abort ();
  59
  60 static int max_opno;
  61
  62 /* Number of operands used in current peephole definition.  */
  63
  64 static int n_operands;
  65
  66 /* Peephole optimizations get insn codes just like insn patterns.
  67    Count them so we know the code of the define_peephole we are handling.  */
  68
  69 static int insn_code_number = 0;
  70
  71 static void print_path ();
  72 static void print_code ();
  73 \f
  74 static void
  75 gen_peephole (peep)
  76      rtx peep;
  77 {
  78   int ninsns = XVECLEN (peep, 0);
  79   int i;
  80
  81   n_operands = 0;
  82
  83   printf ("  insn = ins1;\n");
  84 #if 0
  85   printf ("  want_jump = 0;\n");
  86 #endif
  87
  88   for (i = 0; i < ninsns; i++)
  89     {
  90       if (i > 0)
  91         {
  92           printf ("  do { insn = NEXT_INSN (insn);\n");
  93           printf ("       if (insn == 0) goto L%d; }\n",
  94                   insn_code_number);
  95           printf ("  while (GET_CODE (insn) == NOTE\n");
  96           printf ("\t || (GET_CODE (insn) == INSN\n");
  97           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  98           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  99
 100           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
 101       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
 102                   insn_code_number);
 103         }
 104
 105 #if 0
 106       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
 107       printf ("    want_jump = JUMP_LABEL (insn);\n");
 108 #endif
 109
 110       printf ("  pat = PATTERN (insn);\n");
 111
 112       /* Walk the insn's pattern, remembering at all times the path
 113          down to the walking point.  */
 114
 115       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 116     }
 117
 118   /* We get this far if the pattern matches.
 119      Now test the extra condition.  */
 120
 121   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 122     printf ("  if (! (%s)) goto L%d;\n",
 123             XSTR (peep, 1), insn_code_number);
 124
 125   /* If that matches, construct new pattern and put it in the first insn.
 126      This new pattern will never be matched.
 127      It exists only so that insn-extract can get the operands back.
 128      So use a simple regular form: a PARALLEL containing a vector
 129      of all the operands.  */
 130
 131   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 132
 133 #if 0
 134   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 135   printf ("    {\n");
 136   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 137   printf ("      delete_insn (ins1);\n");
 138   printf ("      ins1 = ins2;\n");
 139   printf ("    }\n");
 140 #endif
 141
 142   /* Record this define_peephole's insn code in the insn,
 143      as if it had been recognized to match this.  */
 144   printf ("  INSN_CODE (ins1) = %d;\n",
 145           insn_code_number);
 146
 147   /* Delete the remaining insns.  */
 148   if (ninsns > 1)
 149     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 150
 151   /* See reload1.c for insertion of NOTE which guarantees that this
 152      cannot be zero.  */
 153   printf ("  return NEXT_INSN (insn);\n");
 154
 155   printf (" L%d:\n\n", insn_code_number);
 156 }
 157 \f
 158 static void
 159 match_rtx (x, path, fail_label)
 160      rtx x;
 161      struct link *path;
 162      int fail_label;
 163 {
 164   register RTX_CODE code;
 165   register int i;
 166   register int len;
 167   register char *fmt;
 168   struct link link;
 169
 170   if (x == 0)
 171     return;
 172
 173
 174   code = GET_CODE (x);
 175
 176   switch (code)
 177     {
 178     case MATCH_OPERAND:
 179       if (XINT (x, 0) > max_opno)
 180         max_opno = XINT (x, 0);
 181       if (XINT (x, 0) >= n_operands)
 182         n_operands = 1 + XINT (x, 0);
 183
 184       printf ("  x = ");
 185       print_path (path);
 186       printf (";\n");
 187
 188       printf ("  operands[%d] = x;\n", XINT (x, 0));
 189       if (XSTR (x, 1) && XSTR (x, 1)[0])
 190         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 191                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 192       return;
 193
 194     case MATCH_DUP:
 195     case MATCH_PAR_DUP:
 196       printf ("  x = ");
 197       print_path (path);
 198       printf (";\n");
 199
 200       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 201               XINT (x, 0), fail_label);
 202       return;
 203
 204     case MATCH_OP_DUP:
 205       printf ("  x = ");
 206       print_path (path);
 207       printf (";\n");
 208
 209       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 210       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 211               XINT (x, 0), fail_label);
 212       printf ("  operands[%d] = x;\n", XINT (x, 0));
 213       link.next = path;
 214       link.vecelt = -1;
 215       for (i = 0; i < XVECLEN (x, 1); i++)
 216         {
 217           link.pos = i;
 218           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 219         }
 220       return;
 221
 222     case MATCH_OPERATOR:
 223       if (XINT (x, 0) > max_opno)
 224         max_opno = XINT (x, 0);
 225       if (XINT (x, 0) >= n_operands)
 226         n_operands = 1 + XINT (x, 0);
 227
 228       printf ("  x = ");
 229       print_path (path);
 230       printf (";\n");
 231
 232       printf ("  operands[%d] = x;\n", XINT (x, 0));
 233       if (XSTR (x, 1) && XSTR (x, 1)[0])
 234         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 235                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 236       link.next = path;
 237       link.vecelt = -1;
 238       for (i = 0; i < XVECLEN (x, 2); i++)
 239         {
 240           link.pos = i;
 241           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 242         }
 243       return;
 244
 245     case MATCH_PARALLEL:
 246       if (XINT (x, 0) > max_opno)
 247         max_opno = XINT (x, 0);
 248       if (XINT (x, 0) >= n_operands)
 249         n_operands = 1 + XINT (x, 0);
 250
 251       printf ("  x = ");
 252       print_path (path);
 253       printf (";\n");
 254
 255       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 256       printf ("  operands[%d] = x;\n", XINT (x, 0));
 257       if (XSTR (x, 1) && XSTR (x, 1)[0])
 258         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 259                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 260       link.next = path;
 261       link.pos = 0;
 262       for (i = 0; i < XVECLEN (x, 2); i++)
 263         {
 264           link.vecelt = i;
 265           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 266         }
 267       return;
 268
 269     case ADDRESS:
 270       match_rtx (XEXP (x, 0), path, fail_label);
 271       return;
 272
 273     default:
 274       break;
 275     }
 276
 277   printf ("  x = ");
 278   print_path (path);
 279   printf (";\n");
 280
 281   printf ("  if (GET_CODE (x) != ");
 282   print_code (code);
 283   printf (") goto L%d;\n", fail_label);
 284
 285   if (GET_MODE (x) != VOIDmode)
 286     {
 287       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 288               GET_MODE_NAME (GET_MODE (x)), fail_label);
 289     }
 290
 291   link.next = path;
 292   link.vecelt = -1;
 293   fmt = GET_RTX_FORMAT (code);
 294   len = GET_RTX_LENGTH (code);
 295   for (i = 0; i < len; i++)
 296     {
 297       link.pos = i;
 298       if (fmt[i] == 'e' || fmt[i] == 'u')
 299         match_rtx (XEXP (x, i), &link, fail_label);
 300       else if (fmt[i] == 'E')
 301         {
 302           int j;
 303           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 304                   i, XVECLEN (x, i), fail_label);
 305           for (j = 0; j < XVECLEN (x, i); j++)
 306             {
 307               link.vecelt = j;
 308               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 309             }
 310         }
 311       else if (fmt[i] == 'i')
 312         {
 313           /* Make sure that at run time `x' is the RTX we want to test.  */
 314           if (i != 0)
 315             {
 316               printf ("  x = ");
 317               print_path (path);
 318               printf (";\n");
 319             }
 320
 321           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 322                   i, XINT (x, i), fail_label);
 323         }
 324       else if (fmt[i] == 'w')
 325         {
 326           /* Make sure that at run time `x' is the RTX we want to test.  */
 327           if (i != 0)
 328             {
 329               printf ("  x = ");
 330               print_path (path);
 331               printf (";\n");
 332             }
 333
 334           printf ("  if (XWINT (x, %d) != ", i);
 335           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 336           printf (") goto L%d;\n", fail_label);
 337         }
 338       else if (fmt[i] == 's')
 339         {
 340           /* Make sure that at run time `x' is the RTX we want to test.  */
 341           if (i != 0)
 342             {
 343               printf ("  x = ");
 344               print_path (path);
 345               printf (";\n");
 346             }
 347
 348           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 349                   i, XSTR (x, i), fail_label);
 350         }
 351     }
 352 }
 353
 354 /* Given a PATH, representing a path down the instruction's
 355    pattern from the root to a certain point, output code to
 356    evaluate to the rtx at that point.  */
 357
 358 static void
 359 print_path (path)
 360      struct link *path;
 361 {
 362   if (path == 0)
 363     printf ("pat");
 364   else if (path->vecelt >= 0)
 365     {
 366       printf ("XVECEXP (");
 367       print_path (path->next);
 368       printf (", %d, %d)", path->pos, path->vecelt);
 369     }
 370   else
 371     {
 372       printf ("XEXP (");
 373       print_path (path->next);
 374       printf (", %d)", path->pos);
 375     }
 376 }
 377 \f
 378 static void
 379 print_code (code)
 380      RTX_CODE code;
 381 {
 382   register char *p1;
 383   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 384     {
 385       if (*p1 >= 'a' && *p1 <= 'z')
 386         putchar (*p1 + 'A' - 'a');
 387       else
 388         putchar (*p1);
 389     }
 390 }
 391 \f
 392 char *
 393 xmalloc (size)
 394      unsigned size;
 395 {
 396   register char *val = (char *) malloc (size);
 397
 398   if (val == 0)
 399     fatal ("virtual memory exhausted");
 400   return val;
 401 }
 402
 403 char *
 404 xrealloc (ptr, size)
 405      char *ptr;
 406      unsigned size;
 407 {
 408   char *result = (char *) realloc (ptr, size);
 409   if (!result)
 410     fatal ("virtual memory exhausted");
 411   return result;
 412 }
 413
 414 static void
 415 fatal (s, a1, a2)
 416      char *s;
 417 {
 418   fprintf (stderr, "genpeep: ");
 419   fprintf (stderr, s, a1, a2);
 420   fprintf (stderr, "\n");
 421   exit (FATAL_EXIT_CODE);
 422 }
 423
 424 /* More 'friendly' abort that prints the line and file.
 425    config.h can #define abort fancy_abort if you like that sort of thing.  */
 426
 427 void
 428 fancy_abort ()
 429 {
 430   fatal ("Internal gcc abort.");
 431 }
 432 \f
 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 <stdio.h>\n");
 463   printf ("#include \"rtl.h\"\n");
 464   printf ("#include \"regs.h\"\n");
 465   printf ("#include \"output.h\"\n");
 466   printf ("#include \"real.h\"\n");
 467   printf ("#include \"except.h\"\n\n");
 468
 469   printf ("extern rtx peep_operand[];\n\n");
 470   printf ("#define operands peep_operand\n\n");
 471
 472   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 473   printf ("  rtx insn, x, pat;\n");
 474   printf ("  int i;\n\n");
 475
 476   /* Early out: no peepholes for insns followed by barriers.  */
 477   printf ("  if (NEXT_INSN (ins1)\n");
 478   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 479   printf ("    return 0;\n\n");
 480
 481   /* Read the machine description.  */
 482
 483   while (1)
 484     {
 485       c = read_skip_spaces (infile);
 486       if (c == EOF)
 487         break;
 488       ungetc (c, infile);
 489
 490       desc = read_rtx (infile);
 491       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 492         {
 493           gen_peephole (desc);
 494           insn_code_number++;
 495         }
 496       if (GET_CODE (desc) == DEFINE_INSN
 497           || GET_CODE (desc) == DEFINE_EXPAND
 498           || GET_CODE (desc) == DEFINE_SPLIT)
 499         {
 500           insn_code_number++;
 501         }
 502     }
 503
 504   printf ("  return 0;\n}\n\n");
 505
 506   if (max_opno == -1)
 507     max_opno = 1;
 508
 509   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 510
 511   fflush (stdout);
 512   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 513   /* NOTREACHED */
 514   return 0;
 515 }