gas/cond.c

   1 /* cond.c - conditional assembly pseudo-ops, and .include
   2    Copyright 1990, 1991, 1992, 1993, 1995, 1997, 1998, 2000
   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   int dead_tree;
  52   /* Macro nesting level at which this conditional was created.  */
  53   int macro_nest;
  54 };
  55
  56 static void initialize_cframe PARAMS ((struct conditional_frame *cframe));
  57 static char *get_mri_string PARAMS ((int, int *));
  58
  59 static struct conditional_frame *current_cframe = NULL;
  60
  61 void
  62 s_ifdef (arg)
  63      int arg;
  64 {
  65   /* Points to name of symbol.  */
  66   register char *name;
  67   /* Points to symbol.  */
  68   register symbolS *symbolP;
  69   struct conditional_frame cframe;
  70
  71   /* Leading whitespace is part of operand.  */
  72   SKIP_WHITESPACE ();
  73   name = input_line_pointer;
  74
  75   if (!is_name_beginner (*name))
  76     {
  77       as_bad (_("invalid identifier for \".ifdef\""));
  78       obstack_1grow (&cond_obstack, 0);
  79       ignore_rest_of_line ();
  80     }
  81   else
  82     {
  83       char c;
  84
  85       c = get_symbol_end ();
  86       symbolP = symbol_find (name);
  87       *input_line_pointer = c;
  88
  89       initialize_cframe (&cframe);
  90       cframe.ignoring = cframe.dead_tree || !((symbolP != 0) ^ arg);
  91       current_cframe = ((struct conditional_frame *)
  92                         obstack_copy (&cond_obstack, &cframe,
  93                                       sizeof (cframe)));
  94
  95       if (LISTING_SKIP_COND ()
  96           && cframe.ignoring
  97           && (cframe.previous_cframe == NULL
  98               || ! cframe.previous_cframe->ignoring))
  99         listing_list (2);
 100
 101       demand_empty_rest_of_line ();
 102     }                           /* if a valid identifyer name */
 103 }
 104
 105 void
 106 s_if (arg)
 107      int arg;
 108 {
 109   expressionS operand;
 110   struct conditional_frame cframe;
 111   int t;
 112   char *stop = NULL;
 113   char stopc;
 114
 115   if (flag_mri)
 116     stop = mri_comment_field (&stopc);
 117
 118   /* Leading whitespace is part of operand.  */
 119   SKIP_WHITESPACE ();
 120
 121   if (current_cframe != NULL && current_cframe->ignoring)
 122     {
 123       operand.X_add_number = 0;
 124       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 125         ++input_line_pointer;
 126     }
 127   else
 128     {
 129       expression (&operand);
 130       if (operand.X_op != O_constant)
 131         as_bad (_("non-constant expression in \".if\" statement"));
 132     }
 133
 134   switch ((operatorT) arg)
 135     {
 136     case O_eq: t = operand.X_add_number == 0; break;
 137     case O_ne: t = operand.X_add_number != 0; break;
 138     case O_lt: t = operand.X_add_number < 0; break;
 139     case O_le: t = operand.X_add_number <= 0; break;
 140     case O_ge: t = operand.X_add_number >= 0; break;
 141     case O_gt: t = operand.X_add_number > 0; break;
 142     default:
 143       abort ();
 144       return;
 145     }
 146
 147   /* If the above error is signaled, this will dispatch
 148      using an undefined result.  No big deal.  */
 149   initialize_cframe (&cframe);
 150   cframe.ignoring = cframe.dead_tree || ! t;
 151   current_cframe = ((struct conditional_frame *)
 152                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 153
 154   if (LISTING_SKIP_COND ()
 155       && cframe.ignoring
 156       && (cframe.previous_cframe == NULL
 157           || ! cframe.previous_cframe->ignoring))
 158     listing_list (2);
 159
 160   if (flag_mri)
 161     mri_comment_end (stop, stopc);
 162
 163   demand_empty_rest_of_line ();
 164 }
 165
 166 /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
 167
 168 static char *
 169 get_mri_string (terminator, len)
 170      int terminator;
 171      int *len;
 172 {
 173   char *ret;
 174   char *s;
 175
 176   SKIP_WHITESPACE ();
 177   s = ret = input_line_pointer;
 178   if (*input_line_pointer == '\'')
 179     {
 180       ++s;
 181       ++input_line_pointer;
 182       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 183         {
 184           *s++ = *input_line_pointer++;
 185           if (s[-1] == '\'')
 186             {
 187               if (*input_line_pointer != '\'')
 188                 break;
 189               ++input_line_pointer;
 190             }
 191         }
 192       SKIP_WHITESPACE ();
 193     }
 194   else
 195     {
 196       while (*input_line_pointer != terminator
 197              && ! is_end_of_line[(unsigned char) *input_line_pointer])
 198         ++input_line_pointer;
 199       s = input_line_pointer;
 200       while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
 201         --s;
 202     }
 203
 204   *len = s - ret;
 205   return ret;
 206 }
 207
 208 /* The MRI IFC and IFNC pseudo-ops.  */
 209
 210 void
 211 s_ifc (arg)
 212      int arg;
 213 {
 214   char *stop = NULL;
 215   char stopc;
 216   char *s1, *s2;
 217   int len1, len2;
 218   int res;
 219   struct conditional_frame cframe;
 220
 221   if (flag_mri)
 222     stop = mri_comment_field (&stopc);
 223
 224   s1 = get_mri_string (',', &len1);
 225
 226   if (*input_line_pointer != ',')
 227     as_bad (_("bad format for ifc or ifnc"));
 228   else
 229     ++input_line_pointer;
 230
 231   s2 = get_mri_string (';', &len2);
 232
 233   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 234
 235   initialize_cframe (&cframe);
 236   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 237   current_cframe = ((struct conditional_frame *)
 238                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 239
 240   if (LISTING_SKIP_COND ()
 241       && cframe.ignoring
 242       && (cframe.previous_cframe == NULL
 243           || ! cframe.previous_cframe->ignoring))
 244     listing_list (2);
 245
 246   if (flag_mri)
 247     mri_comment_end (stop, stopc);
 248
 249   demand_empty_rest_of_line ();
 250 }
 251
 252 void
 253 s_elseif (arg)
 254      int arg;
 255 {
 256   expressionS operand;
 257   int t;
 258
 259   if (current_cframe == NULL)
 260     {
 261       as_bad (_("\".elseif\" without matching \".if\" - ignored"));
 262
 263     }
 264   else if (current_cframe->else_seen)
 265     {
 266       as_bad (_("\".elseif\" after \".else\" - ignored"));
 267       as_bad_where (current_cframe->else_file_line.file,
 268                     current_cframe->else_file_line.line,
 269                     _("here is the previous \"else\""));
 270       as_bad_where (current_cframe->if_file_line.file,
 271                     current_cframe->if_file_line.line,
 272                     _("here is the previous \"if\""));
 273     }
 274   else
 275     {
 276       as_where (&current_cframe->else_file_line.file,
 277                 &current_cframe->else_file_line.line);
 278
 279       if (!current_cframe->dead_tree)
 280         {
 281           current_cframe->ignoring = !current_cframe->ignoring;
 282           if (LISTING_SKIP_COND ())
 283             {
 284               if (! current_cframe->ignoring)
 285                 listing_list (1);
 286               else
 287                 listing_list (2);
 288             }
 289         }                       /* if not a dead tree */
 290     }                           /* if error else do it */
 291
 292   /* Leading whitespace is part of operand.  */
 293   SKIP_WHITESPACE ();
 294
 295   if (current_cframe != NULL && current_cframe->ignoring)
 296     {
 297       operand.X_add_number = 0;
 298       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 299         ++input_line_pointer;
 300     }
 301   else
 302     {
 303       expression (&operand);
 304       if (operand.X_op != O_constant)
 305         as_bad (_("non-constant expression in \".elseif\" statement"));
 306     }
 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 }