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   if (current_cframe == NULL)
 259     {
 260       as_bad (_("\".elseif\" without matching \".if\""));
 261     }
 262   else if (current_cframe->else_seen)
 263     {
 264       as_bad (_("\".elseif\" after \".else\""));
 265       as_bad_where (current_cframe->else_file_line.file,
 266                     current_cframe->else_file_line.line,
 267                     _("here is the previous \"else\""));
 268       as_bad_where (current_cframe->if_file_line.file,
 269                     current_cframe->if_file_line.line,
 270                     _("here is the previous \"if\""));
 271     }
 272   else
 273     {
 274       as_where (&current_cframe->else_file_line.file,
 275                 &current_cframe->else_file_line.line);
 276
 277       current_cframe->dead_tree |= !current_cframe->ignoring;
 278       current_cframe->ignoring = current_cframe->dead_tree;
 279     }
 280
 281   if (current_cframe == NULL || current_cframe->ignoring)
 282     {
 283       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 284         ++input_line_pointer;
 285
 286       if (current_cframe == NULL)
 287         return;
 288     }
 289   else
 290     {
 291       expressionS operand;
 292       int t;
 293
 294       /* Leading whitespace is part of operand.  */
 295       SKIP_WHITESPACE ();
 296
 297       expression (&operand);
 298       if (operand.X_op != O_constant)
 299         as_bad (_("non-constant expression in \".elseif\" statement"));
 300
 301       switch ((operatorT) arg)
 302         {
 303         case O_eq: t = operand.X_add_number == 0; break;
 304         case O_ne: t = operand.X_add_number != 0; break;
 305         case O_lt: t = operand.X_add_number < 0; break;
 306         case O_le: t = operand.X_add_number <= 0; break;
 307         case O_ge: t = operand.X_add_number >= 0; break;
 308         case O_gt: t = operand.X_add_number > 0; break;
 309         default:
 310           abort ();
 311           return;
 312         }
 313
 314       current_cframe->ignoring = current_cframe->dead_tree || ! t;
 315     }
 316
 317   if (LISTING_SKIP_COND ()
 318       && (current_cframe->previous_cframe == NULL
 319           || ! current_cframe->previous_cframe->ignoring))
 320     {
 321       if (! current_cframe->ignoring)
 322         listing_list (1);
 323       else
 324         listing_list (2);
 325     }
 326
 327   demand_empty_rest_of_line ();
 328 }
 329
 330 void
 331 s_endif (arg)
 332      int arg ATTRIBUTE_UNUSED;
 333 {
 334   struct conditional_frame *hold;
 335
 336   if (current_cframe == NULL)
 337     {
 338       as_bad (_("\".endif\" without \".if\""));
 339     }
 340   else
 341     {
 342       if (LISTING_SKIP_COND ()
 343           && current_cframe->ignoring
 344           && (current_cframe->previous_cframe == NULL
 345               || ! current_cframe->previous_cframe->ignoring))
 346         listing_list (1);
 347
 348       hold = current_cframe;
 349       current_cframe = current_cframe->previous_cframe;
 350       obstack_free (&cond_obstack, hold);
 351     }                           /* if one pop too many */
 352
 353   if (flag_mri)
 354     {
 355       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 356         ++input_line_pointer;
 357     }
 358
 359   demand_empty_rest_of_line ();
 360 }
 361
 362 void
 363 s_else (arg)
 364      int arg ATTRIBUTE_UNUSED;
 365 {
 366   if (current_cframe == NULL)
 367     {
 368       as_bad (_("\".else\" without matching \".if\""));
 369     }
 370   else if (current_cframe->else_seen)
 371     {
 372       as_bad (_("duplicate \"else\""));
 373       as_bad_where (current_cframe->else_file_line.file,
 374                     current_cframe->else_file_line.line,
 375                     _("here is the previous \"else\""));
 376       as_bad_where (current_cframe->if_file_line.file,
 377                     current_cframe->if_file_line.line,
 378                     _("here is the previous \"if\""));
 379     }
 380   else
 381     {
 382       as_where (&current_cframe->else_file_line.file,
 383                 &current_cframe->else_file_line.line);
 384
 385       current_cframe->ignoring =
 386         current_cframe->dead_tree | !current_cframe->ignoring;
 387
 388       if (LISTING_SKIP_COND ()
 389           && (current_cframe->previous_cframe == NULL
 390               || ! current_cframe->previous_cframe->ignoring))
 391         {
 392           if (! current_cframe->ignoring)
 393             listing_list (1);
 394           else
 395             listing_list (2);
 396         }
 397
 398       current_cframe->else_seen = 1;
 399     }
 400
 401   if (flag_mri)
 402     {
 403       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 404         ++input_line_pointer;
 405     }
 406
 407   demand_empty_rest_of_line ();
 408 }
 409
 410 void
 411 s_ifeqs (arg)
 412      int arg;
 413 {
 414   char *s1, *s2;
 415   int len1, len2;
 416   int res;
 417   struct conditional_frame cframe;
 418
 419   s1 = demand_copy_C_string (&len1);
 420
 421   SKIP_WHITESPACE ();
 422   if (*input_line_pointer != ',')
 423     {
 424       as_bad (_(".ifeqs syntax error"));
 425       ignore_rest_of_line ();
 426       return;
 427     }
 428
 429   ++input_line_pointer;
 430
 431   s2 = demand_copy_C_string (&len2);
 432
 433   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 434
 435   initialize_cframe (&cframe);
 436   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 437   current_cframe = ((struct conditional_frame *)
 438                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 439
 440   if (LISTING_SKIP_COND ()
 441       && cframe.ignoring
 442       && (cframe.previous_cframe == NULL
 443           || ! cframe.previous_cframe->ignoring))
 444     listing_list (2);
 445
 446   demand_empty_rest_of_line ();
 447 }
 448
 449 int
 450 ignore_input ()
 451 {
 452   char *s;
 453
 454   s = input_line_pointer;
 455
 456   if (NO_PSEUDO_DOT || flag_m68k_mri)
 457     {
 458       if (s[-1] != '.')
 459         --s;
 460     }
 461   else
 462     {
 463       if (s[-1] != '.')
 464         return (current_cframe != NULL) && (current_cframe->ignoring);
 465     }
 466
 467   /* We cannot ignore certain pseudo ops.  */
 468   if (((s[0] == 'i'
 469         || s[0] == 'I')
 470        && (!strncasecmp (s, "if", 2)
 471            || !strncasecmp (s, "ifdef", 5)
 472            || !strncasecmp (s, "ifndef", 6)))
 473       || ((s[0] == 'e'
 474            || s[0] == 'E')
 475           && (!strncasecmp (s, "else", 4)
 476               || !strncasecmp (s, "endif", 5)
 477               || !strncasecmp (s, "endc", 4))))
 478     return 0;
 479
 480   return (current_cframe != NULL) && (current_cframe->ignoring);
 481 }
 482
 483 static void
 484 initialize_cframe (cframe)
 485      struct conditional_frame *cframe;
 486 {
 487   memset (cframe, 0, sizeof (*cframe));
 488   as_where (&cframe->if_file_line.file,
 489             &cframe->if_file_line.line);
 490   cframe->previous_cframe = current_cframe;
 491   cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
 492   cframe->macro_nest = macro_nest;
 493 }
 494
 495 /* Give an error if a conditional is unterminated inside a macro or
 496    the assembly as a whole.  If NEST is non negative, we are being
 497    called because of the end of a macro expansion.  If NEST is
 498    negative, we are being called at the of the input files.  */
 499
 500 void
 501 cond_finish_check (nest)
 502      int nest;
 503 {
 504   if (current_cframe != NULL && current_cframe->macro_nest >= nest)
 505     {
 506       if (nest >= 0)
 507         as_bad (_("end of macro inside conditional"));
 508       else
 509         as_bad (_("end of file inside conditional"));
 510       as_bad_where (current_cframe->if_file_line.file,
 511                     current_cframe->if_file_line.line,
 512                     _("here is the start of the unterminated conditional"));
 513       if (current_cframe->else_seen)
 514         as_bad_where (current_cframe->else_file_line.file,
 515                       current_cframe->else_file_line.line,
 516                       _("here is the \"else\" of the unterminated conditional"));
 517     }
 518 }
 519
 520 /* This function is called when we exit out of a macro.  We assume
 521    that any conditionals which began within the macro are correctly
 522    nested, and just pop them off the stack.  */
 523
 524 void
 525 cond_exit_macro (nest)
 526      int nest;
 527 {
 528   while (current_cframe != NULL && current_cframe->macro_nest >= nest)
 529     {
 530       struct conditional_frame *hold;
 531
 532       hold = current_cframe;
 533       current_cframe = current_cframe->previous_cframe;
 534       obstack_free (&cond_obstack, hold);
 535     }
 536 }