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 /* Performs the .ifdef (test_defined == 1) and
  64    the .ifndef (test_defined == 0) pseudo op.  */
  65
  66 void
  67 s_ifdef (test_defined)
  68      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)
 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 (arg)
 127      int arg;
 128 {
 129   expressionS operand;
 130   struct conditional_frame cframe;
 131   int t;
 132   char *stop = NULL;
 133   char stopc;
 134
 135   if (flag_mri)
 136     stop = mri_comment_field (&stopc);
 137
 138   /* Leading whitespace is part of operand.  */
 139   SKIP_WHITESPACE ();
 140
 141   if (current_cframe != NULL && current_cframe->ignoring)
 142     {
 143       operand.X_add_number = 0;
 144       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 145         ++input_line_pointer;
 146     }
 147   else
 148     {
 149       expression (&operand);
 150       if (operand.X_op != O_constant)
 151         as_bad (_("non-constant expression in \".if\" statement"));
 152     }
 153
 154   switch ((operatorT) arg)
 155     {
 156     case O_eq: t = operand.X_add_number == 0; break;
 157     case O_ne: t = operand.X_add_number != 0; break;
 158     case O_lt: t = operand.X_add_number < 0; break;
 159     case O_le: t = operand.X_add_number <= 0; break;
 160     case O_ge: t = operand.X_add_number >= 0; break;
 161     case O_gt: t = operand.X_add_number > 0; break;
 162     default:
 163       abort ();
 164       return;
 165     }
 166
 167   /* If the above error is signaled, this will dispatch
 168      using an undefined result.  No big deal.  */
 169   initialize_cframe (&cframe);
 170   cframe.ignoring = cframe.dead_tree || ! t;
 171   current_cframe = ((struct conditional_frame *)
 172                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 173
 174   if (LISTING_SKIP_COND ()
 175       && cframe.ignoring
 176       && (cframe.previous_cframe == NULL
 177           || ! cframe.previous_cframe->ignoring))
 178     listing_list (2);
 179
 180   if (flag_mri)
 181     mri_comment_end (stop, stopc);
 182
 183   demand_empty_rest_of_line ();
 184 }
 185
 186 /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
 187
 188 static char *
 189 get_mri_string (terminator, len)
 190      int terminator;
 191      int *len;
 192 {
 193   char *ret;
 194   char *s;
 195
 196   SKIP_WHITESPACE ();
 197   s = ret = input_line_pointer;
 198   if (*input_line_pointer == '\'')
 199     {
 200       ++s;
 201       ++input_line_pointer;
 202       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 203         {
 204           *s++ = *input_line_pointer++;
 205           if (s[-1] == '\'')
 206             {
 207               if (*input_line_pointer != '\'')
 208                 break;
 209               ++input_line_pointer;
 210             }
 211         }
 212       SKIP_WHITESPACE ();
 213     }
 214   else
 215     {
 216       while (*input_line_pointer != terminator
 217              && ! is_end_of_line[(unsigned char) *input_line_pointer])
 218         ++input_line_pointer;
 219       s = input_line_pointer;
 220       while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
 221         --s;
 222     }
 223
 224   *len = s - ret;
 225   return ret;
 226 }
 227
 228 /* The MRI IFC and IFNC pseudo-ops.  */
 229
 230 void
 231 s_ifc (arg)
 232      int arg;
 233 {
 234   char *stop = NULL;
 235   char stopc;
 236   char *s1, *s2;
 237   int len1, len2;
 238   int res;
 239   struct conditional_frame cframe;
 240
 241   if (flag_mri)
 242     stop = mri_comment_field (&stopc);
 243
 244   s1 = get_mri_string (',', &len1);
 245
 246   if (*input_line_pointer != ',')
 247     as_bad (_("bad format for ifc or ifnc"));
 248   else
 249     ++input_line_pointer;
 250
 251   s2 = get_mri_string (';', &len2);
 252
 253   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 254
 255   initialize_cframe (&cframe);
 256   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 257   current_cframe = ((struct conditional_frame *)
 258                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 259
 260   if (LISTING_SKIP_COND ()
 261       && cframe.ignoring
 262       && (cframe.previous_cframe == NULL
 263           || ! cframe.previous_cframe->ignoring))
 264     listing_list (2);
 265
 266   if (flag_mri)
 267     mri_comment_end (stop, stopc);
 268
 269   demand_empty_rest_of_line ();
 270 }
 271
 272 void
 273 s_elseif (arg)
 274      int arg;
 275 {
 276   if (current_cframe == NULL)
 277     {
 278       as_bad (_("\".elseif\" without matching \".if\""));
 279     }
 280   else if (current_cframe->else_seen)
 281     {
 282       as_bad (_("\".elseif\" after \".else\""));
 283       as_bad_where (current_cframe->else_file_line.file,
 284                     current_cframe->else_file_line.line,
 285                     _("here is the previous \"else\""));
 286       as_bad_where (current_cframe->if_file_line.file,
 287                     current_cframe->if_file_line.line,
 288                     _("here is the previous \"if\""));
 289     }
 290   else
 291     {
 292       as_where (&current_cframe->else_file_line.file,
 293                 &current_cframe->else_file_line.line);
 294
 295       current_cframe->dead_tree |= !current_cframe->ignoring;
 296       current_cframe->ignoring = current_cframe->dead_tree;
 297     }
 298
 299   if (current_cframe == NULL || current_cframe->ignoring)
 300     {
 301       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 302         ++input_line_pointer;
 303
 304       if (current_cframe == NULL)
 305         return;
 306     }
 307   else
 308     {
 309       expressionS operand;
 310       int t;
 311
 312       /* Leading whitespace is part of operand.  */
 313       SKIP_WHITESPACE ();
 314
 315       expression (&operand);
 316       if (operand.X_op != O_constant)
 317         as_bad (_("non-constant expression in \".elseif\" statement"));
 318
 319       switch ((operatorT) arg)
 320         {
 321         case O_eq: t = operand.X_add_number == 0; break;
 322         case O_ne: t = operand.X_add_number != 0; break;
 323         case O_lt: t = operand.X_add_number < 0; break;
 324         case O_le: t = operand.X_add_number <= 0; break;
 325         case O_ge: t = operand.X_add_number >= 0; break;
 326         case O_gt: t = operand.X_add_number > 0; break;
 327         default:
 328           abort ();
 329           return;
 330         }
 331
 332       current_cframe->ignoring = current_cframe->dead_tree || ! t;
 333     }
 334
 335   if (LISTING_SKIP_COND ()
 336       && (current_cframe->previous_cframe == NULL
 337           || ! current_cframe->previous_cframe->ignoring))
 338     {
 339       if (! current_cframe->ignoring)
 340         listing_list (1);
 341       else
 342         listing_list (2);
 343     }
 344
 345   demand_empty_rest_of_line ();
 346 }
 347
 348 void
 349 s_endif (arg)
 350      int arg ATTRIBUTE_UNUSED;
 351 {
 352   struct conditional_frame *hold;
 353
 354   if (current_cframe == NULL)
 355     {
 356       as_bad (_("\".endif\" without \".if\""));
 357     }
 358   else
 359     {
 360       if (LISTING_SKIP_COND ()
 361           && current_cframe->ignoring
 362           && (current_cframe->previous_cframe == NULL
 363               || ! current_cframe->previous_cframe->ignoring))
 364         listing_list (1);
 365
 366       hold = current_cframe;
 367       current_cframe = current_cframe->previous_cframe;
 368       obstack_free (&cond_obstack, hold);
 369     }                           /* if one pop too many */
 370
 371   if (flag_mri)
 372     {
 373       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 374         ++input_line_pointer;
 375     }
 376
 377   demand_empty_rest_of_line ();
 378 }
 379
 380 void
 381 s_else (arg)
 382      int arg ATTRIBUTE_UNUSED;
 383 {
 384   if (current_cframe == NULL)
 385     {
 386       as_bad (_("\".else\" without matching \".if\""));
 387     }
 388   else if (current_cframe->else_seen)
 389     {
 390       as_bad (_("duplicate \"else\""));
 391       as_bad_where (current_cframe->else_file_line.file,
 392                     current_cframe->else_file_line.line,
 393                     _("here is the previous \"else\""));
 394       as_bad_where (current_cframe->if_file_line.file,
 395                     current_cframe->if_file_line.line,
 396                     _("here is the previous \"if\""));
 397     }
 398   else
 399     {
 400       as_where (&current_cframe->else_file_line.file,
 401                 &current_cframe->else_file_line.line);
 402
 403       current_cframe->ignoring =
 404         current_cframe->dead_tree | !current_cframe->ignoring;
 405
 406       if (LISTING_SKIP_COND ()
 407           && (current_cframe->previous_cframe == NULL
 408               || ! current_cframe->previous_cframe->ignoring))
 409         {
 410           if (! current_cframe->ignoring)
 411             listing_list (1);
 412           else
 413             listing_list (2);
 414         }
 415
 416       current_cframe->else_seen = 1;
 417     }
 418
 419   if (flag_mri)
 420     {
 421       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 422         ++input_line_pointer;
 423     }
 424
 425   demand_empty_rest_of_line ();
 426 }
 427
 428 void
 429 s_ifeqs (arg)
 430      int arg;
 431 {
 432   char *s1, *s2;
 433   int len1, len2;
 434   int res;
 435   struct conditional_frame cframe;
 436
 437   s1 = demand_copy_C_string (&len1);
 438
 439   SKIP_WHITESPACE ();
 440   if (*input_line_pointer != ',')
 441     {
 442       as_bad (_(".ifeqs syntax error"));
 443       ignore_rest_of_line ();
 444       return;
 445     }
 446
 447   ++input_line_pointer;
 448
 449   s2 = demand_copy_C_string (&len2);
 450
 451   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 452
 453   initialize_cframe (&cframe);
 454   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 455   current_cframe = ((struct conditional_frame *)
 456                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 457
 458   if (LISTING_SKIP_COND ()
 459       && cframe.ignoring
 460       && (cframe.previous_cframe == NULL
 461           || ! cframe.previous_cframe->ignoring))
 462     listing_list (2);
 463
 464   demand_empty_rest_of_line ();
 465 }
 466
 467 int
 468 ignore_input ()
 469 {
 470   char *s;
 471
 472   s = input_line_pointer;
 473
 474   if (NO_PSEUDO_DOT || flag_m68k_mri)
 475     {
 476       if (s[-1] != '.')
 477         --s;
 478     }
 479   else
 480     {
 481       if (s[-1] != '.')
 482         return (current_cframe != NULL) && (current_cframe->ignoring);
 483     }
 484
 485   /* We cannot ignore certain pseudo ops.  */
 486   if (((s[0] == 'i'
 487         || s[0] == 'I')
 488        && (!strncasecmp (s, "if", 2)
 489            || !strncasecmp (s, "ifdef", 5)
 490            || !strncasecmp (s, "ifndef", 6)))
 491       || ((s[0] == 'e'
 492            || s[0] == 'E')
 493           && (!strncasecmp (s, "else", 4)
 494               || !strncasecmp (s, "endif", 5)
 495               || !strncasecmp (s, "endc", 4))))
 496     return 0;
 497
 498   return (current_cframe != NULL) && (current_cframe->ignoring);
 499 }
 500
 501 static void
 502 initialize_cframe (cframe)
 503      struct conditional_frame *cframe;
 504 {
 505   memset (cframe, 0, sizeof (*cframe));
 506   as_where (&cframe->if_file_line.file,
 507             &cframe->if_file_line.line);
 508   cframe->previous_cframe = current_cframe;
 509   cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
 510   cframe->macro_nest = macro_nest;
 511 }
 512
 513 /* Give an error if a conditional is unterminated inside a macro or
 514    the assembly as a whole.  If NEST is non negative, we are being
 515    called because of the end of a macro expansion.  If NEST is
 516    negative, we are being called at the of the input files.  */
 517
 518 void
 519 cond_finish_check (nest)
 520      int nest;
 521 {
 522   if (current_cframe != NULL && current_cframe->macro_nest >= nest)
 523     {
 524       if (nest >= 0)
 525         as_bad (_("end of macro inside conditional"));
 526       else
 527         as_bad (_("end of file inside conditional"));
 528       as_bad_where (current_cframe->if_file_line.file,
 529                     current_cframe->if_file_line.line,
 530                     _("here is the start of the unterminated conditional"));
 531       if (current_cframe->else_seen)
 532         as_bad_where (current_cframe->else_file_line.file,
 533                       current_cframe->else_file_line.line,
 534                       _("here is the \"else\" of the unterminated conditional"));
 535     }
 536 }
 537
 538 /* This function is called when we exit out of a macro.  We assume
 539    that any conditionals which began within the macro are correctly
 540    nested, and just pop them off the stack.  */
 541
 542 void
 543 cond_exit_macro (nest)
 544      int nest;
 545 {
 546   while (current_cframe != NULL && current_cframe->macro_nest >= nest)
 547     {
 548       struct conditional_frame *hold;
 549
 550       hold = current_cframe;
 551       current_cframe = current_cframe->previous_cframe;
 552       obstack_free (&cond_obstack, hold);
 553     }
 554 }