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, 2005, 2006, 2007 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 3, 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, 51 Franklin Street - Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 #include "as.h"
  23 #include "sb.h"
  24 #include "macro.h"
  25
  26 #include "obstack.h"
  27
  28 /* This is allocated to grow and shrink as .ifdef/.endif pairs are
  29    scanned.  */
  30 struct obstack cond_obstack;
  31
  32 struct file_line {
  33   char *file;
  34   unsigned int line;
  35 };
  36
  37 /* We push one of these structures for each .if, and pop it at the
  38    .endif.  */
  39
  40 struct conditional_frame {
  41   /* The source file & line number of the "if".  */
  42   struct file_line if_file_line;
  43   /* The source file & line of the "else".  */
  44   struct file_line else_file_line;
  45   /* The previous conditional.  */
  46   struct conditional_frame *previous_cframe;
  47   /* Have we seen an else yet?  */
  48   int else_seen;
  49   /* Whether we are currently ignoring input.  */
  50   int ignoring;
  51   /* Whether a conditional at a higher level is ignoring input.
  52      Set also when a branch of an "if .. elseif .." tree has matched
  53      to prevent further matches.  */
  54   int dead_tree;
  55   /* Macro nesting level at which this conditional was created.  */
  56   int macro_nest;
  57 };
  58
  59 static void initialize_cframe (struct conditional_frame *cframe);
  60 static char *get_mri_string (int, int *);
  61
  62 static struct conditional_frame *current_cframe = NULL;
  63
  64 /* Performs the .ifdef (test_defined == 1) and
  65    the .ifndef (test_defined == 0) pseudo op.  */
  66
  67 void
  68 s_ifdef (int test_defined)
  69 {
  70   /* Points to name of symbol.  */
  71   char *name;
  72   /* Points to symbol.  */
  73   symbolS *symbolP;
  74   struct conditional_frame cframe;
  75   char c;
  76
  77   /* Leading whitespace is part of operand.  */
  78   SKIP_WHITESPACE ();
  79   name = input_line_pointer;
  80
  81   if (!is_name_beginner (*name))
  82     {
  83       as_bad (_("invalid identifier for \".ifdef\""));
  84       obstack_1grow (&cond_obstack, 0);
  85       ignore_rest_of_line ();
  86       return;
  87     }
  88
  89   c = get_symbol_end ();
  90   symbolP = symbol_find (name);
  91   *input_line_pointer = c;
  92
  93   initialize_cframe (&cframe);
  94
  95   if (cframe.dead_tree)
  96     cframe.ignoring = 1;
  97   else
  98     {
  99       int is_defined;
 100
 101       /* Use the same definition of 'defined' as .equiv so that a symbol
 102          which has been referenced but not yet given a value/address is
 103          considered to be undefined.  */
 104       is_defined =
 105         symbolP != NULL
 106         && (S_IS_DEFINED (symbolP) || symbol_equated_p (symbolP))
 107         && S_GET_SEGMENT (symbolP) != reg_section;
 108
 109       cframe.ignoring = ! (test_defined ^ is_defined);
 110     }
 111
 112   current_cframe = ((struct conditional_frame *)
 113                     obstack_copy (&cond_obstack, &cframe,
 114                                   sizeof (cframe)));
 115
 116   if (LISTING_SKIP_COND ()
 117       && cframe.ignoring
 118       && (cframe.previous_cframe == NULL
 119           || ! cframe.previous_cframe->ignoring))
 120     listing_list (2);
 121
 122   demand_empty_rest_of_line ();
 123 }
 124
 125 void
 126 s_if (int arg)
 127 {
 128   expressionS operand;
 129   struct conditional_frame cframe;
 130   int t;
 131   char *stop = NULL;
 132   char stopc;
 133
 134   if (flag_mri)
 135     stop = mri_comment_field (&stopc);
 136
 137   /* Leading whitespace is part of operand.  */
 138   SKIP_WHITESPACE ();
 139
 140   if (current_cframe != NULL && current_cframe->ignoring)
 141     {
 142       operand.X_add_number = 0;
 143       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 144         ++input_line_pointer;
 145     }
 146   else
 147     {
 148       expression_and_evaluate (&operand);
 149       if (operand.X_op != O_constant)
 150         as_bad (_("non-constant expression in \".if\" statement"));
 151     }
 152
 153   switch ((operatorT) arg)
 154     {
 155     case O_eq: t = operand.X_add_number == 0; break;
 156     case O_ne: t = operand.X_add_number != 0; break;
 157     case O_lt: t = operand.X_add_number < 0; break;
 158     case O_le: t = operand.X_add_number <= 0; break;
 159     case O_ge: t = operand.X_add_number >= 0; break;
 160     case O_gt: t = operand.X_add_number > 0; break;
 161     default:
 162       abort ();
 163       return;
 164     }
 165
 166   /* If the above error is signaled, this will dispatch
 167      using an undefined result.  No big deal.  */
 168   initialize_cframe (&cframe);
 169   cframe.ignoring = cframe.dead_tree || ! t;
 170   current_cframe = ((struct conditional_frame *)
 171                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 172
 173   if (LISTING_SKIP_COND ()
 174       && cframe.ignoring
 175       && (cframe.previous_cframe == NULL
 176           || ! cframe.previous_cframe->ignoring))
 177     listing_list (2);
 178
 179   if (flag_mri)
 180     mri_comment_end (stop, stopc);
 181
 182   demand_empty_rest_of_line ();
 183 }
 184
 185 /* Performs the .ifb (test_blank == 1) and
 186    the .ifnb (test_blank == 0) pseudo op.  */
 187
 188 void
 189 s_ifb (int test_blank)
 190 {
 191   struct conditional_frame cframe;
 192
 193   initialize_cframe (&cframe);
 194
 195   if (cframe.dead_tree)
 196     cframe.ignoring = 1;
 197   else
 198     {
 199       int is_eol;
 200
 201       SKIP_WHITESPACE ();
 202       is_eol = is_end_of_line[(unsigned char) *input_line_pointer];
 203       cframe.ignoring = (test_blank == !is_eol);
 204     }
 205
 206   current_cframe = ((struct conditional_frame *)
 207                     obstack_copy (&cond_obstack, &cframe,
 208                                   sizeof (cframe)));
 209
 210   if (LISTING_SKIP_COND ()
 211       && cframe.ignoring
 212       && (cframe.previous_cframe == NULL
 213           || ! cframe.previous_cframe->ignoring))
 214     listing_list (2);
 215
 216   ignore_rest_of_line ();
 217 }
 218
 219 /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
 220
 221 static char *
 222 get_mri_string (int terminator, int *len)
 223 {
 224   char *ret;
 225   char *s;
 226
 227   SKIP_WHITESPACE ();
 228   s = ret = input_line_pointer;
 229   if (*input_line_pointer == '\'')
 230     {
 231       ++s;
 232       ++input_line_pointer;
 233       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 234         {
 235           *s++ = *input_line_pointer++;
 236           if (s[-1] == '\'')
 237             {
 238               if (*input_line_pointer != '\'')
 239                 break;
 240               ++input_line_pointer;
 241             }
 242         }
 243       SKIP_WHITESPACE ();
 244     }
 245   else
 246     {
 247       while (*input_line_pointer != terminator
 248              && ! is_end_of_line[(unsigned char) *input_line_pointer])
 249         ++input_line_pointer;
 250       s = input_line_pointer;
 251       while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
 252         --s;
 253     }
 254
 255   *len = s - ret;
 256   return ret;
 257 }
 258
 259 /* The MRI IFC and IFNC pseudo-ops.  */
 260
 261 void
 262 s_ifc (int arg)
 263 {
 264   char *stop = NULL;
 265   char stopc;
 266   char *s1, *s2;
 267   int len1, len2;
 268   int res;
 269   struct conditional_frame cframe;
 270
 271   if (flag_mri)
 272     stop = mri_comment_field (&stopc);
 273
 274   s1 = get_mri_string (',', &len1);
 275
 276   if (*input_line_pointer != ',')
 277     as_bad (_("bad format for ifc or ifnc"));
 278   else
 279     ++input_line_pointer;
 280
 281   s2 = get_mri_string (';', &len2);
 282
 283   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 284
 285   initialize_cframe (&cframe);
 286   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 287   current_cframe = ((struct conditional_frame *)
 288                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 289
 290   if (LISTING_SKIP_COND ()
 291       && cframe.ignoring
 292       && (cframe.previous_cframe == NULL
 293           || ! cframe.previous_cframe->ignoring))
 294     listing_list (2);
 295
 296   if (flag_mri)
 297     mri_comment_end (stop, stopc);
 298
 299   demand_empty_rest_of_line ();
 300 }
 301
 302 void
 303 s_elseif (int arg)
 304 {
 305   if (current_cframe == NULL)
 306     {
 307       as_bad (_("\".elseif\" without matching \".if\""));
 308     }
 309   else if (current_cframe->else_seen)
 310     {
 311       as_bad (_("\".elseif\" after \".else\""));
 312       as_bad_where (current_cframe->else_file_line.file,
 313                     current_cframe->else_file_line.line,
 314                     _("here is the previous \"else\""));
 315       as_bad_where (current_cframe->if_file_line.file,
 316                     current_cframe->if_file_line.line,
 317                     _("here is the previous \"if\""));
 318     }
 319   else
 320     {
 321       as_where (&current_cframe->else_file_line.file,
 322                 &current_cframe->else_file_line.line);
 323
 324       current_cframe->dead_tree |= !current_cframe->ignoring;
 325       current_cframe->ignoring = current_cframe->dead_tree;
 326     }
 327
 328   if (current_cframe == NULL || current_cframe->ignoring)
 329     {
 330       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 331         ++input_line_pointer;
 332
 333       if (current_cframe == NULL)
 334         return;
 335     }
 336   else
 337     {
 338       expressionS operand;
 339       int t;
 340
 341       /* Leading whitespace is part of operand.  */
 342       SKIP_WHITESPACE ();
 343
 344       expression_and_evaluate (&operand);
 345       if (operand.X_op != O_constant)
 346         as_bad (_("non-constant expression in \".elseif\" statement"));
 347
 348       switch ((operatorT) arg)
 349         {
 350         case O_eq: t = operand.X_add_number == 0; break;
 351         case O_ne: t = operand.X_add_number != 0; break;
 352         case O_lt: t = operand.X_add_number < 0; break;
 353         case O_le: t = operand.X_add_number <= 0; break;
 354         case O_ge: t = operand.X_add_number >= 0; break;
 355         case O_gt: t = operand.X_add_number > 0; break;
 356         default:
 357           abort ();
 358           return;
 359         }
 360
 361       current_cframe->ignoring = current_cframe->dead_tree || ! t;
 362     }
 363
 364   if (LISTING_SKIP_COND ()
 365       && (current_cframe->previous_cframe == NULL
 366           || ! current_cframe->previous_cframe->ignoring))
 367     {
 368       if (! current_cframe->ignoring)
 369         listing_list (1);
 370       else
 371         listing_list (2);
 372     }
 373
 374   demand_empty_rest_of_line ();
 375 }
 376
 377 void
 378 s_endif (int arg ATTRIBUTE_UNUSED)
 379 {
 380   struct conditional_frame *hold;
 381
 382   if (current_cframe == NULL)
 383     {
 384       as_bad (_("\".endif\" without \".if\""));
 385     }
 386   else
 387     {
 388       if (LISTING_SKIP_COND ()
 389           && current_cframe->ignoring
 390           && (current_cframe->previous_cframe == NULL
 391               || ! current_cframe->previous_cframe->ignoring))
 392         listing_list (1);
 393
 394       hold = current_cframe;
 395       current_cframe = current_cframe->previous_cframe;
 396       obstack_free (&cond_obstack, hold);
 397     }                           /* if one pop too many */
 398
 399   if (flag_mri)
 400     {
 401       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 402         ++input_line_pointer;
 403     }
 404
 405   demand_empty_rest_of_line ();
 406 }
 407
 408 void
 409 s_else (int arg ATTRIBUTE_UNUSED)
 410 {
 411   if (current_cframe == NULL)
 412     {
 413       as_bad (_("\".else\" without matching \".if\""));
 414     }
 415   else if (current_cframe->else_seen)
 416     {
 417       as_bad (_("duplicate \"else\""));
 418       as_bad_where (current_cframe->else_file_line.file,
 419                     current_cframe->else_file_line.line,
 420                     _("here is the previous \"else\""));
 421       as_bad_where (current_cframe->if_file_line.file,
 422                     current_cframe->if_file_line.line,
 423                     _("here is the previous \"if\""));
 424     }
 425   else
 426     {
 427       as_where (&current_cframe->else_file_line.file,
 428                 &current_cframe->else_file_line.line);
 429
 430       current_cframe->ignoring =
 431         current_cframe->dead_tree | !current_cframe->ignoring;
 432
 433       if (LISTING_SKIP_COND ()
 434           && (current_cframe->previous_cframe == NULL
 435               || ! current_cframe->previous_cframe->ignoring))
 436         {
 437           if (! current_cframe->ignoring)
 438             listing_list (1);
 439           else
 440             listing_list (2);
 441         }
 442
 443       current_cframe->else_seen = 1;
 444     }
 445
 446   if (flag_mri)
 447     {
 448       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 449         ++input_line_pointer;
 450     }
 451
 452   demand_empty_rest_of_line ();
 453 }
 454
 455 void
 456 s_ifeqs (int arg)
 457 {
 458   char *s1, *s2;
 459   int len1, len2;
 460   int res;
 461   struct conditional_frame cframe;
 462
 463   s1 = demand_copy_C_string (&len1);
 464
 465   SKIP_WHITESPACE ();
 466   if (*input_line_pointer != ',')
 467     {
 468       as_bad (_(".ifeqs syntax error"));
 469       ignore_rest_of_line ();
 470       return;
 471     }
 472
 473   ++input_line_pointer;
 474
 475   s2 = demand_copy_C_string (&len2);
 476
 477   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 478
 479   initialize_cframe (&cframe);
 480   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 481   current_cframe = ((struct conditional_frame *)
 482                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 483
 484   if (LISTING_SKIP_COND ()
 485       && cframe.ignoring
 486       && (cframe.previous_cframe == NULL
 487           || ! cframe.previous_cframe->ignoring))
 488     listing_list (2);
 489
 490   demand_empty_rest_of_line ();
 491 }
 492
 493 int
 494 ignore_input (void)
 495 {
 496   char *s;
 497
 498   s = input_line_pointer;
 499
 500   if (NO_PSEUDO_DOT || flag_m68k_mri)
 501     {
 502       if (s[-1] != '.')
 503         --s;
 504     }
 505   else
 506     {
 507       if (s[-1] != '.')
 508         return (current_cframe != NULL) && (current_cframe->ignoring);
 509     }
 510
 511   /* We cannot ignore certain pseudo ops.  */
 512   if (((s[0] == 'i'
 513         || s[0] == 'I')
 514        && (!strncasecmp (s, "if", 2)
 515            || !strncasecmp (s, "ifdef", 5)
 516            || !strncasecmp (s, "ifndef", 6)))
 517       || ((s[0] == 'e'
 518            || s[0] == 'E')
 519           && (!strncasecmp (s, "else", 4)
 520               || !strncasecmp (s, "endif", 5)
 521               || !strncasecmp (s, "endc", 4))))
 522     return 0;
 523
 524   return (current_cframe != NULL) && (current_cframe->ignoring);
 525 }
 526
 527 static void
 528 initialize_cframe (struct conditional_frame *cframe)
 529 {
 530   memset (cframe, 0, sizeof (*cframe));
 531   as_where (&cframe->if_file_line.file,
 532             &cframe->if_file_line.line);
 533   cframe->previous_cframe = current_cframe;
 534   cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
 535   cframe->macro_nest = macro_nest;
 536 }
 537
 538 /* Give an error if a conditional is unterminated inside a macro or
 539    the assembly as a whole.  If NEST is non negative, we are being
 540    called because of the end of a macro expansion.  If NEST is
 541    negative, we are being called at the of the input files.  */
 542
 543 void
 544 cond_finish_check (int nest)
 545 {
 546   if (current_cframe != NULL && current_cframe->macro_nest >= nest)
 547     {
 548       if (nest >= 0)
 549         as_bad (_("end of macro inside conditional"));
 550       else
 551         as_bad (_("end of file inside conditional"));
 552       as_bad_where (current_cframe->if_file_line.file,
 553                     current_cframe->if_file_line.line,
 554                     _("here is the start of the unterminated conditional"));
 555       if (current_cframe->else_seen)
 556         as_bad_where (current_cframe->else_file_line.file,
 557                       current_cframe->else_file_line.line,
 558                       _("here is the \"else\" of the unterminated conditional"));
 559     }
 560 }
 561
 562 /* This function is called when we exit out of a macro.  We assume
 563    that any conditionals which began within the macro are correctly
 564    nested, and just pop them off the stack.  */
 565
 566 void
 567 cond_exit_macro (int nest)
 568 {
 569   while (current_cframe != NULL && current_cframe->macro_nest >= nest)
 570     {
 571       struct conditional_frame *hold;
 572
 573       hold = current_cframe;
 574       current_cframe = current_cframe->previous_cframe;
 575       obstack_free (&cond_obstack, hold);
 576     }
 577 }