gas/cond.c

   1 /* cond.c - conditional assembly pseudo-ops, and .include
   2    Copyright 1990, 1991, 1992, 1993, 1995, 1997, 1998, 2000, 2001
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GAS is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  22 #include "as.h"
  23 #include "macro.h"
  24
  25 #include "obstack.h"
  26
  27 /* This is allocated to grow and shrink as .ifdef/.endif pairs are
  28    scanned.  */
  29 struct obstack cond_obstack;
  30
  31 struct file_line {
  32   char *file;
  33   unsigned int line;
  34 };
  35
  36 /* We push one of these structures for each .if, and pop it at the
  37    .endif.  */
  38
  39 struct conditional_frame {
  40   /* The source file & line number of the "if".  */
  41   struct file_line if_file_line;
  42   /* The source file & line of the "else".  */
  43   struct file_line else_file_line;
  44   /* The previous conditional.  */
  45   struct conditional_frame *previous_cframe;
  46   /* Have we seen an else yet?  */
  47   int else_seen;
  48   /* Whether we are currently ignoring input.  */
  49   int ignoring;
  50   /* Whether a conditional at a higher level is ignoring input.
  51      Set also when a branch of an "if .. elseif .." tree has matched
  52      to prevent further matches.  */
  53   int dead_tree;
  54   /* Macro nesting level at which this conditional was created.  */
  55   int macro_nest;
  56 };
  57
  58 static void initialize_cframe PARAMS ((struct conditional_frame *cframe));
  59 static char *get_mri_string PARAMS ((int, int *));
  60
  61 static struct conditional_frame *current_cframe = NULL;
  62
  63 void
  64 s_ifdef (arg)
  65      int arg;
  66 {
  67   /* Points to name of symbol.  */
  68   register char *name;
  69   /* Points to symbol.  */
  70   register symbolS *symbolP;
  71   struct conditional_frame cframe;
  72
  73   /* Leading whitespace is part of operand.  */
  74   SKIP_WHITESPACE ();
  75   name = input_line_pointer;
  76
  77   if (!is_name_beginner (*name))
  78     {
  79       as_bad (_("invalid identifier for \".ifdef\""));
  80       obstack_1grow (&cond_obstack, 0);
  81       ignore_rest_of_line ();
  82     }
  83   else
  84     {
  85       char c;
  86
  87       c = get_symbol_end ();
  88       symbolP = symbol_find (name);
  89       *input_line_pointer = c;
  90
  91       initialize_cframe (&cframe);
  92       cframe.ignoring = cframe.dead_tree || !((symbolP != 0) ^ arg);
  93       current_cframe = ((struct conditional_frame *)
  94                         obstack_copy (&cond_obstack, &cframe,
  95                                       sizeof (cframe)));
  96
  97       if (LISTING_SKIP_COND ()
  98           && cframe.ignoring
  99           && (cframe.previous_cframe == NULL
 100               || ! cframe.previous_cframe->ignoring))
 101         listing_list (2);
 102
 103       demand_empty_rest_of_line ();
 104     }                           /* if a valid identifyer name */
 105 }
 106
 107 void
 108 s_if (arg)
 109      int arg;
 110 {
 111   expressionS operand;
 112   struct conditional_frame cframe;
 113   int t;
 114   char *stop = NULL;
 115   char stopc;
 116
 117   if (flag_mri)
 118     stop = mri_comment_field (&stopc);
 119
 120   /* Leading whitespace is part of operand.  */
 121   SKIP_WHITESPACE ();
 122
 123   if (current_cframe != NULL && current_cframe->ignoring)
 124     {
 125       operand.X_add_number = 0;
 126       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 127         ++input_line_pointer;
 128     }
 129   else
 130     {
 131       expression (&operand);
 132       if (operand.X_op != O_constant)
 133         as_bad (_("non-constant expression in \".if\" statement"));
 134     }
 135
 136   switch ((operatorT) arg)
 137     {
 138     case O_eq: t = operand.X_add_number == 0; break;
 139     case O_ne: t = operand.X_add_number != 0; break;
 140     case O_lt: t = operand.X_add_number < 0; break;
 141     case O_le: t = operand.X_add_number <= 0; break;
 142     case O_ge: t = operand.X_add_number >= 0; break;
 143     case O_gt: t = operand.X_add_number > 0; break;
 144     default:
 145       abort ();
 146       return;
 147     }
 148
 149   /* If the above error is signaled, this will dispatch
 150      using an undefined result.  No big deal.  */
 151   initialize_cframe (&cframe);
 152   cframe.ignoring = cframe.dead_tree || ! t;
 153   current_cframe = ((struct conditional_frame *)
 154                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 155
 156   if (LISTING_SKIP_COND ()
 157       && cframe.ignoring
 158       && (cframe.previous_cframe == NULL
 159           || ! cframe.previous_cframe->ignoring))
 160     listing_list (2);
 161
 162   if (flag_mri)
 163     mri_comment_end (stop, stopc);
 164
 165   demand_empty_rest_of_line ();
 166 }
 167
 168 /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
 169
 170 static char *
 171 get_mri_string (terminator, len)
 172      int terminator;
 173      int *len;
 174 {
 175   char *ret;
 176   char *s;
 177
 178   SKIP_WHITESPACE ();
 179   s = ret = input_line_pointer;
 180   if (*input_line_pointer == '\'')
 181     {
 182       ++s;
 183       ++input_line_pointer;
 184       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 185         {
 186           *s++ = *input_line_pointer++;
 187           if (s[-1] == '\'')
 188             {
 189               if (*input_line_pointer != '\'')
 190                 break;
 191               ++input_line_pointer;
 192             }
 193         }
 194       SKIP_WHITESPACE ();
 195     }
 196   else
 197     {
 198       while (*input_line_pointer != terminator
 199              && ! is_end_of_line[(unsigned char) *input_line_pointer])
 200         ++input_line_pointer;
 201       s = input_line_pointer;
 202       while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
 203         --s;
 204     }
 205
 206   *len = s - ret;
 207   return ret;
 208 }
 209
 210 /* The MRI IFC and IFNC pseudo-ops.  */
 211
 212 void
 213 s_ifc (arg)
 214      int arg;
 215 {
 216   char *stop = NULL;
 217   char stopc;
 218   char *s1, *s2;
 219   int len1, len2;
 220   int res;
 221   struct conditional_frame cframe;
 222
 223   if (flag_mri)
 224     stop = mri_comment_field (&stopc);
 225
 226   s1 = get_mri_string (',', &len1);
 227
 228   if (*input_line_pointer != ',')
 229     as_bad (_("bad format for ifc or ifnc"));
 230   else
 231     ++input_line_pointer;
 232
 233   s2 = get_mri_string (';', &len2);
 234
 235   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 236
 237   initialize_cframe (&cframe);
 238   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 239   current_cframe = ((struct conditional_frame *)
 240                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 241
 242   if (LISTING_SKIP_COND ()
 243       && cframe.ignoring
 244       && (cframe.previous_cframe == NULL
 245           || ! cframe.previous_cframe->ignoring))
 246     listing_list (2);
 247
 248   if (flag_mri)
 249     mri_comment_end (stop, stopc);
 250
 251   demand_empty_rest_of_line ();
 252 }
 253
 254 void
 255 s_elseif (arg)
 256      int arg;
 257 {
 258   expressionS operand;
 259   int t;
 260
 261   if (current_cframe == NULL)
 262     {
 263       as_bad (_("\".elseif\" without matching \".if\" - ignored"));
 264     }
 265   else if (current_cframe->else_seen)
 266     {
 267       as_bad (_("\".elseif\" after \".else\" - ignored"));
 268       as_bad_where (current_cframe->else_file_line.file,
 269                     current_cframe->else_file_line.line,
 270                     _("here is the previous \"else\""));
 271       as_bad_where (current_cframe->if_file_line.file,
 272                     current_cframe->if_file_line.line,
 273                     _("here is the previous \"if\""));
 274     }
 275   else
 276     {
 277       as_where (&current_cframe->else_file_line.file,
 278                 &current_cframe->else_file_line.line);
 279
 280       if (!current_cframe->dead_tree)
 281         {
 282           current_cframe->dead_tree = !current_cframe->ignoring;
 283           current_cframe->ignoring = !current_cframe->ignoring;
 284           if (LISTING_SKIP_COND ())
 285             {
 286               if (! current_cframe->ignoring)
 287                 listing_list (1);
 288               else
 289                 listing_list (2);
 290             }
 291         }                       /* if not a dead tree */
 292     }                           /* if error else do it */
 293
 294   if (current_cframe == NULL || current_cframe->ignoring)
 295     {
 296       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 297         ++input_line_pointer;
 298       return;
 299     }
 300
 301   /* Leading whitespace is part of operand.  */
 302   SKIP_WHITESPACE ();
 303
 304   expression (&operand);
 305   if (operand.X_op != O_constant)
 306     as_bad (_("non-constant expression in \".elseif\" statement"));
 307
 308   switch ((operatorT) arg)
 309     {
 310     case O_eq: t = operand.X_add_number == 0; break;
 311     case O_ne: t = operand.X_add_number != 0; break;
 312     case O_lt: t = operand.X_add_number < 0; break;
 313     case O_le: t = operand.X_add_number <= 0; break;
 314     case O_ge: t = operand.X_add_number >= 0; break;
 315     case O_gt: t = operand.X_add_number > 0; break;
 316     default:
 317       abort ();
 318       return;
 319     }
 320
 321   current_cframe->ignoring = current_cframe->dead_tree || ! t;
 322
 323   if (LISTING_SKIP_COND ()
 324       && current_cframe->ignoring
 325       && (current_cframe->previous_cframe == NULL
 326           || ! current_cframe->previous_cframe->ignoring))
 327     listing_list (2);
 328
 329   demand_empty_rest_of_line ();
 330 }
 331
 332 void
 333 s_endif (arg)
 334      int arg ATTRIBUTE_UNUSED;
 335 {
 336   struct conditional_frame *hold;
 337
 338   if (current_cframe == NULL)
 339     {
 340       as_bad (_("\".endif\" without \".if\""));
 341     }
 342   else
 343     {
 344       if (LISTING_SKIP_COND ()
 345           && current_cframe->ignoring
 346           && (current_cframe->previous_cframe == NULL
 347               || ! current_cframe->previous_cframe->ignoring))
 348         listing_list (1);
 349
 350       hold = current_cframe;
 351       current_cframe = current_cframe->previous_cframe;
 352       obstack_free (&cond_obstack, hold);
 353     }                           /* if one pop too many */
 354
 355   if (flag_mri)
 356     {
 357       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 358         ++input_line_pointer;
 359     }
 360
 361   demand_empty_rest_of_line ();
 362 }
 363
 364 void
 365 s_else (arg)
 366      int arg ATTRIBUTE_UNUSED;
 367 {
 368   if (current_cframe == NULL)
 369     {
 370       as_bad (_(".else without matching .if - ignored"));
 371
 372     }
 373   else if (current_cframe->else_seen)
 374     {
 375       as_bad (_("duplicate \"else\" - ignored"));
 376       as_bad_where (current_cframe->else_file_line.file,
 377                     current_cframe->else_file_line.line,
 378                     _("here is the previous \"else\""));
 379       as_bad_where (current_cframe->if_file_line.file,
 380                     current_cframe->if_file_line.line,
 381                     _("here is the previous \"if\""));
 382     }
 383   else
 384     {
 385       as_where (&current_cframe->else_file_line.file,
 386                 &current_cframe->else_file_line.line);
 387
 388       if (!current_cframe->dead_tree)
 389         {
 390           current_cframe->ignoring = !current_cframe->ignoring;
 391           if (LISTING_SKIP_COND ())
 392             {
 393               if (! current_cframe->ignoring)
 394                 listing_list (1);
 395               else
 396                 listing_list (2);
 397             }
 398         }                       /* if not a dead tree */
 399
 400       current_cframe->else_seen = 1;
 401     }                           /* if error else do it */
 402
 403   if (flag_mri)
 404     {
 405       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 406         ++input_line_pointer;
 407     }
 408
 409   demand_empty_rest_of_line ();
 410 }
 411
 412 void
 413 s_ifeqs (arg)
 414      int arg;
 415 {
 416   char *s1, *s2;
 417   int len1, len2;
 418   int res;
 419   struct conditional_frame cframe;
 420
 421   s1 = demand_copy_C_string (&len1);
 422
 423   SKIP_WHITESPACE ();
 424   if (*input_line_pointer != ',')
 425     {
 426       as_bad (_(".ifeqs syntax error"));
 427       ignore_rest_of_line ();
 428       return;
 429     }
 430
 431   ++input_line_pointer;
 432
 433   s2 = demand_copy_C_string (&len2);
 434
 435   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 436
 437   initialize_cframe (&cframe);
 438   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 439   current_cframe = ((struct conditional_frame *)
 440                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 441
 442   if (LISTING_SKIP_COND ()
 443       && cframe.ignoring
 444       && (cframe.previous_cframe == NULL
 445           || ! cframe.previous_cframe->ignoring))
 446     listing_list (2);
 447
 448   demand_empty_rest_of_line ();
 449 }
 450
 451 int
 452 ignore_input ()
 453 {
 454   char *s;
 455
 456   s = input_line_pointer;
 457
 458   if (NO_PSEUDO_DOT || flag_m68k_mri)
 459     {
 460       if (s[-1] != '.')
 461         --s;
 462     }
 463   else
 464     {
 465       if (s[-1] != '.')
 466         return (current_cframe != NULL) && (current_cframe->ignoring);
 467     }
 468
 469   /* We cannot ignore certain pseudo ops.  */
 470   if (((s[0] == 'i'
 471         || s[0] == 'I')
 472        && (!strncasecmp (s, "if", 2)
 473            || !strncasecmp (s, "ifdef", 5)
 474            || !strncasecmp (s, "ifndef", 6)))
 475       || ((s[0] == 'e'
 476            || s[0] == 'E')
 477           && (!strncasecmp (s, "else", 4)
 478               || !strncasecmp (s, "endif", 5)
 479               || !strncasecmp (s, "endc", 4))))
 480     return 0;
 481
 482   return (current_cframe != NULL) && (current_cframe->ignoring);
 483 }
 484
 485 static void
 486 initialize_cframe (cframe)
 487      struct conditional_frame *cframe;
 488 {
 489   memset (cframe, 0, sizeof (*cframe));
 490   as_where (&cframe->if_file_line.file,
 491             &cframe->if_file_line.line);
 492   cframe->previous_cframe = current_cframe;
 493   cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
 494   cframe->macro_nest = macro_nest;
 495 }
 496
 497 /* Give an error if a conditional is unterminated inside a macro or
 498    the assembly as a whole.  If NEST is non negative, we are being
 499    called because of the end of a macro expansion.  If NEST is
 500    negative, we are being called at the of the input files.  */
 501
 502 void
 503 cond_finish_check (nest)
 504      int nest;
 505 {
 506   if (current_cframe != NULL && current_cframe->macro_nest >= nest)
 507     {
 508       if (nest >= 0)
 509         as_bad (_("end of macro inside conditional"));
 510       else
 511         as_bad (_("end of file inside conditional"));
 512       as_bad_where (current_cframe->if_file_line.file,
 513                     current_cframe->if_file_line.line,
 514                     _("here is the start of the unterminated conditional"));
 515       if (current_cframe->else_seen)
 516         as_bad_where (current_cframe->else_file_line.file,
 517                       current_cframe->else_file_line.line,
 518                       _("here is the \"else\" of the unterminated conditional"));
 519     }
 520 }
 521
 522 /* This function is called when we exit out of a macro.  We assume
 523    that any conditionals which began within the macro are correctly
 524    nested, and just pop them off the stack.  */
 525
 526 void
 527 cond_exit_macro (nest)
 528      int nest;
 529 {
 530   while (current_cframe != NULL && current_cframe->macro_nest >= nest)
 531     {
 532       struct conditional_frame *hold;
 533
 534       hold = current_cframe;
 535       current_cframe = current_cframe->previous_cframe;
 536       obstack_free (&cond_obstack, hold);
 537     }
 538 }