gas/cond.c

   1 /* cond.c - conditional assembly pseudo-ops, and .include
   2    Copyright 1990, 1991, 1992, 1993, 1995, 1997, 1998, 2000, 2001, 2002,
   3    2003 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 (struct conditional_frame *cframe);
  59 static char *get_mri_string (int, int *);
  60
  61 static struct conditional_frame *current_cframe = NULL;
  62
  63 /* Performs the .ifdef (test_defined == 1) and
  64    the .ifndef (test_defined == 0) pseudo op.  */
  65
  66 void
  67 s_ifdef (int test_defined)
  68 {
  69   /* Points to name of symbol.  */
  70   char *name;
  71   /* Points to symbol.  */
  72   symbolS *symbolP;
  73   struct conditional_frame cframe;
  74   char c;
  75
  76   /* Leading whitespace is part of operand.  */
  77   SKIP_WHITESPACE ();
  78   name = input_line_pointer;
  79
  80   if (!is_name_beginner (*name))
  81     {
  82       as_bad (_("invalid identifier for \".ifdef\""));
  83       obstack_1grow (&cond_obstack, 0);
  84       ignore_rest_of_line ();
  85       return;
  86     }
  87
  88   c = get_symbol_end ();
  89   symbolP = symbol_find (name);
  90   *input_line_pointer = c;
  91
  92   initialize_cframe (&cframe);
  93
  94   if (cframe.dead_tree)
  95     cframe.ignoring = 1;
  96   else
  97     {
  98       int is_defined;
  99
 100       /* Use the same definition of 'defined' as .equiv so that a symbol
 101          which has been referenced but not yet given a value/address is
 102          considered to be undefined.  */
 103       is_defined =
 104         symbolP != NULL
 105         && S_IS_DEFINED (symbolP)
 106         && S_GET_SEGMENT (symbolP) != reg_section;
 107
 108       cframe.ignoring = ! (test_defined ^ is_defined);
 109     }
 110
 111   current_cframe = ((struct conditional_frame *)
 112                     obstack_copy (&cond_obstack, &cframe,
 113                                   sizeof (cframe)));
 114
 115   if (LISTING_SKIP_COND ()
 116       && cframe.ignoring
 117       && (cframe.previous_cframe == NULL
 118           || ! cframe.previous_cframe->ignoring))
 119     listing_list (2);
 120
 121   demand_empty_rest_of_line ();
 122 }
 123
 124 void
 125 s_if (int arg)
 126 {
 127   expressionS operand;
 128   struct conditional_frame cframe;
 129   int t;
 130   char *stop = NULL;
 131   char stopc;
 132
 133   if (flag_mri)
 134     stop = mri_comment_field (&stopc);
 135
 136   /* Leading whitespace is part of operand.  */
 137   SKIP_WHITESPACE ();
 138
 139   if (current_cframe != NULL && current_cframe->ignoring)
 140     {
 141       operand.X_add_number = 0;
 142       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 143         ++input_line_pointer;
 144     }
 145   else
 146     {
 147       expression (&operand);
 148       if (operand.X_op != O_constant)
 149         as_bad (_("non-constant expression in \".if\" statement"));
 150     }
 151
 152   switch ((operatorT) arg)
 153     {
 154     case O_eq: t = operand.X_add_number == 0; break;
 155     case O_ne: t = operand.X_add_number != 0; break;
 156     case O_lt: t = operand.X_add_number < 0; break;
 157     case O_le: t = operand.X_add_number <= 0; break;
 158     case O_ge: t = operand.X_add_number >= 0; break;
 159     case O_gt: t = operand.X_add_number > 0; break;
 160     default:
 161       abort ();
 162       return;
 163     }
 164
 165   /* If the above error is signaled, this will dispatch
 166      using an undefined result.  No big deal.  */
 167   initialize_cframe (&cframe);
 168   cframe.ignoring = cframe.dead_tree || ! t;
 169   current_cframe = ((struct conditional_frame *)
 170                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 171
 172   if (LISTING_SKIP_COND ()
 173       && cframe.ignoring
 174       && (cframe.previous_cframe == NULL
 175           || ! cframe.previous_cframe->ignoring))
 176     listing_list (2);
 177
 178   if (flag_mri)
 179     mri_comment_end (stop, stopc);
 180
 181   demand_empty_rest_of_line ();
 182 }
 183
 184 /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
 185
 186 static char *
 187 get_mri_string (int terminator, int *len)
 188 {
 189   char *ret;
 190   char *s;
 191
 192   SKIP_WHITESPACE ();
 193   s = ret = input_line_pointer;
 194   if (*input_line_pointer == '\'')
 195     {
 196       ++s;
 197       ++input_line_pointer;
 198       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 199         {
 200           *s++ = *input_line_pointer++;
 201           if (s[-1] == '\'')
 202             {
 203               if (*input_line_pointer != '\'')
 204                 break;
 205               ++input_line_pointer;
 206             }
 207         }
 208       SKIP_WHITESPACE ();
 209     }
 210   else
 211     {
 212       while (*input_line_pointer != terminator
 213              && ! is_end_of_line[(unsigned char) *input_line_pointer])
 214         ++input_line_pointer;
 215       s = input_line_pointer;
 216       while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
 217         --s;
 218     }
 219
 220   *len = s - ret;
 221   return ret;
 222 }
 223
 224 /* The MRI IFC and IFNC pseudo-ops.  */
 225
 226 void
 227 s_ifc (int arg)
 228 {
 229   char *stop = NULL;
 230   char stopc;
 231   char *s1, *s2;
 232   int len1, len2;
 233   int res;
 234   struct conditional_frame cframe;
 235
 236   if (flag_mri)
 237     stop = mri_comment_field (&stopc);
 238
 239   s1 = get_mri_string (',', &len1);
 240
 241   if (*input_line_pointer != ',')
 242     as_bad (_("bad format for ifc or ifnc"));
 243   else
 244     ++input_line_pointer;
 245
 246   s2 = get_mri_string (';', &len2);
 247
 248   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 249
 250   initialize_cframe (&cframe);
 251   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 252   current_cframe = ((struct conditional_frame *)
 253                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 254
 255   if (LISTING_SKIP_COND ()
 256       && cframe.ignoring
 257       && (cframe.previous_cframe == NULL
 258           || ! cframe.previous_cframe->ignoring))
 259     listing_list (2);
 260
 261   if (flag_mri)
 262     mri_comment_end (stop, stopc);
 263
 264   demand_empty_rest_of_line ();
 265 }
 266
 267 void
 268 s_elseif (int arg)
 269 {
 270   if (current_cframe == NULL)
 271     {
 272       as_bad (_("\".elseif\" without matching \".if\""));
 273     }
 274   else if (current_cframe->else_seen)
 275     {
 276       as_bad (_("\".elseif\" after \".else\""));
 277       as_bad_where (current_cframe->else_file_line.file,
 278                     current_cframe->else_file_line.line,
 279                     _("here is the previous \"else\""));
 280       as_bad_where (current_cframe->if_file_line.file,
 281                     current_cframe->if_file_line.line,
 282                     _("here is the previous \"if\""));
 283     }
 284   else
 285     {
 286       as_where (&current_cframe->else_file_line.file,
 287                 &current_cframe->else_file_line.line);
 288
 289       current_cframe->dead_tree |= !current_cframe->ignoring;
 290       current_cframe->ignoring = current_cframe->dead_tree;
 291     }
 292
 293   if (current_cframe == NULL || current_cframe->ignoring)
 294     {
 295       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 296         ++input_line_pointer;
 297
 298       if (current_cframe == NULL)
 299         return;
 300     }
 301   else
 302     {
 303       expressionS operand;
 304       int t;
 305
 306       /* Leading whitespace is part of operand.  */
 307       SKIP_WHITESPACE ();
 308
 309       expression (&operand);
 310       if (operand.X_op != O_constant)
 311         as_bad (_("non-constant expression in \".elseif\" statement"));
 312
 313       switch ((operatorT) arg)
 314         {
 315         case O_eq: t = operand.X_add_number == 0; break;
 316         case O_ne: t = operand.X_add_number != 0; break;
 317         case O_lt: t = operand.X_add_number < 0; break;
 318         case O_le: t = operand.X_add_number <= 0; break;
 319         case O_ge: t = operand.X_add_number >= 0; break;
 320         case O_gt: t = operand.X_add_number > 0; break;
 321         default:
 322           abort ();
 323           return;
 324         }
 325
 326       current_cframe->ignoring = current_cframe->dead_tree || ! t;
 327     }
 328
 329   if (LISTING_SKIP_COND ()
 330       && (current_cframe->previous_cframe == NULL
 331           || ! current_cframe->previous_cframe->ignoring))
 332     {
 333       if (! current_cframe->ignoring)
 334         listing_list (1);
 335       else
 336         listing_list (2);
 337     }
 338
 339   demand_empty_rest_of_line ();
 340 }
 341
 342 void
 343 s_endif (int arg ATTRIBUTE_UNUSED)
 344 {
 345   struct conditional_frame *hold;
 346
 347   if (current_cframe == NULL)
 348     {
 349       as_bad (_("\".endif\" without \".if\""));
 350     }
 351   else
 352     {
 353       if (LISTING_SKIP_COND ()
 354           && current_cframe->ignoring
 355           && (current_cframe->previous_cframe == NULL
 356               || ! current_cframe->previous_cframe->ignoring))
 357         listing_list (1);
 358
 359       hold = current_cframe;
 360       current_cframe = current_cframe->previous_cframe;
 361       obstack_free (&cond_obstack, hold);
 362     }                           /* if one pop too many */
 363
 364   if (flag_mri)
 365     {
 366       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 367         ++input_line_pointer;
 368     }
 369
 370   demand_empty_rest_of_line ();
 371 }
 372
 373 void
 374 s_else (int arg ATTRIBUTE_UNUSED)
 375 {
 376   if (current_cframe == NULL)
 377     {
 378       as_bad (_("\".else\" without matching \".if\""));
 379     }
 380   else if (current_cframe->else_seen)
 381     {
 382       as_bad (_("duplicate \"else\""));
 383       as_bad_where (current_cframe->else_file_line.file,
 384                     current_cframe->else_file_line.line,
 385                     _("here is the previous \"else\""));
 386       as_bad_where (current_cframe->if_file_line.file,
 387                     current_cframe->if_file_line.line,
 388                     _("here is the previous \"if\""));
 389     }
 390   else
 391     {
 392       as_where (&current_cframe->else_file_line.file,
 393                 &current_cframe->else_file_line.line);
 394
 395       current_cframe->ignoring =
 396         current_cframe->dead_tree | !current_cframe->ignoring;
 397
 398       if (LISTING_SKIP_COND ()
 399           && (current_cframe->previous_cframe == NULL
 400               || ! current_cframe->previous_cframe->ignoring))
 401         {
 402           if (! current_cframe->ignoring)
 403             listing_list (1);
 404           else
 405             listing_list (2);
 406         }
 407
 408       current_cframe->else_seen = 1;
 409     }
 410
 411   if (flag_mri)
 412     {
 413       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 414         ++input_line_pointer;
 415     }
 416
 417   demand_empty_rest_of_line ();
 418 }
 419
 420 void
 421 s_ifeqs (int arg)
 422 {
 423   char *s1, *s2;
 424   int len1, len2;
 425   int res;
 426   struct conditional_frame cframe;
 427
 428   s1 = demand_copy_C_string (&len1);
 429
 430   SKIP_WHITESPACE ();
 431   if (*input_line_pointer != ',')
 432     {
 433       as_bad (_(".ifeqs syntax error"));
 434       ignore_rest_of_line ();
 435       return;
 436     }
 437
 438   ++input_line_pointer;
 439
 440   s2 = demand_copy_C_string (&len2);
 441
 442   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 443
 444   initialize_cframe (&cframe);
 445   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 446   current_cframe = ((struct conditional_frame *)
 447                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 448
 449   if (LISTING_SKIP_COND ()
 450       && cframe.ignoring
 451       && (cframe.previous_cframe == NULL
 452           || ! cframe.previous_cframe->ignoring))
 453     listing_list (2);
 454
 455   demand_empty_rest_of_line ();
 456 }
 457
 458 int
 459 ignore_input (void)
 460 {
 461   char *s;
 462
 463   s = input_line_pointer;
 464
 465   if (NO_PSEUDO_DOT || flag_m68k_mri)
 466     {
 467       if (s[-1] != '.')
 468         --s;
 469     }
 470   else
 471     {
 472       if (s[-1] != '.')
 473         return (current_cframe != NULL) && (current_cframe->ignoring);
 474     }
 475
 476   /* We cannot ignore certain pseudo ops.  */
 477   if (((s[0] == 'i'
 478         || s[0] == 'I')
 479        && (!strncasecmp (s, "if", 2)
 480            || !strncasecmp (s, "ifdef", 5)
 481            || !strncasecmp (s, "ifndef", 6)))
 482       || ((s[0] == 'e'
 483            || s[0] == 'E')
 484           && (!strncasecmp (s, "else", 4)
 485               || !strncasecmp (s, "endif", 5)
 486               || !strncasecmp (s, "endc", 4))))
 487     return 0;
 488
 489   return (current_cframe != NULL) && (current_cframe->ignoring);
 490 }
 491
 492 static void
 493 initialize_cframe (struct conditional_frame *cframe)
 494 {
 495   memset (cframe, 0, sizeof (*cframe));
 496   as_where (&cframe->if_file_line.file,
 497             &cframe->if_file_line.line);
 498   cframe->previous_cframe = current_cframe;
 499   cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
 500   cframe->macro_nest = macro_nest;
 501 }
 502
 503 /* Give an error if a conditional is unterminated inside a macro or
 504    the assembly as a whole.  If NEST is non negative, we are being
 505    called because of the end of a macro expansion.  If NEST is
 506    negative, we are being called at the of the input files.  */
 507
 508 void
 509 cond_finish_check (int nest)
 510 {
 511   if (current_cframe != NULL && current_cframe->macro_nest >= nest)
 512     {
 513       if (nest >= 0)
 514         as_bad (_("end of macro inside conditional"));
 515       else
 516         as_bad (_("end of file inside conditional"));
 517       as_bad_where (current_cframe->if_file_line.file,
 518                     current_cframe->if_file_line.line,
 519                     _("here is the start of the unterminated conditional"));
 520       if (current_cframe->else_seen)
 521         as_bad_where (current_cframe->else_file_line.file,
 522                       current_cframe->else_file_line.line,
 523                       _("here is the \"else\" of the unterminated conditional"));
 524     }
 525 }
 526
 527 /* This function is called when we exit out of a macro.  We assume
 528    that any conditionals which began within the macro are correctly
 529    nested, and just pop them off the stack.  */
 530
 531 void
 532 cond_exit_macro (int nest)
 533 {
 534   while (current_cframe != NULL && current_cframe->macro_nest >= nest)
 535     {
 536       struct conditional_frame *hold;
 537
 538       hold = current_cframe;
 539       current_cframe = current_cframe->previous_cframe;
 540       obstack_free (&cond_obstack, hold);
 541     }
 542 }