gas/cond.c

   1 /* cond.c - conditional assembly pseudo-ops, and .include
   2    Copyright (C) 1990, 91, 92, 93, 95, 96, 97, 98, 1999
   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 scanned. */
  28 struct obstack cond_obstack;
  29
  30 struct file_line
  31 {
  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 {
  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   int dead_tree;
  53   /* Macro nesting level at which this conditional was created.  */
  54   int macro_nest;
  55 };
  56
  57 static void initialize_cframe PARAMS ((struct conditional_frame *cframe));
  58 static char *get_mri_string PARAMS ((int, int *));
  59
  60 static struct conditional_frame *current_cframe = NULL;
  61
  62 void
  63 s_ifdef (arg)
  64      int arg;
  65 {
  66   register char *name;          /* points to name of symbol */
  67   register symbolS *symbolP;    /* Points to symbol */
  68   struct conditional_frame cframe;
  69
  70   SKIP_WHITESPACE ();           /* Leading whitespace is part of operand. */
  71   name = input_line_pointer;
  72
  73   if (!is_name_beginner (*name))
  74     {
  75       as_bad (_("invalid identifier for \".ifdef\""));
  76       obstack_1grow (&cond_obstack, 0);
  77       ignore_rest_of_line ();
  78     }
  79   else
  80     {
  81       char c;
  82
  83       c = get_symbol_end ();
  84       symbolP = symbol_find (name);
  85       *input_line_pointer = c;
  86
  87       initialize_cframe (&cframe);
  88       cframe.ignoring = cframe.dead_tree || !((symbolP != 0) ^ arg);
  89       current_cframe = ((struct conditional_frame *)
  90                         obstack_copy (&cond_obstack, &cframe,
  91                                       sizeof (cframe)));
  92
  93       if (LISTING_SKIP_COND ()
  94           && cframe.ignoring
  95           && (cframe.previous_cframe == NULL
  96               || ! cframe.previous_cframe->ignoring))
  97         listing_list (2);
  98
  99       demand_empty_rest_of_line ();
 100     }                           /* if a valid identifyer name */
 101 }                               /* s_ifdef() */
 102
 103 void
 104 s_if (arg)
 105      int arg;
 106 {
 107   expressionS operand;
 108   struct conditional_frame cframe;
 109   int t;
 110   char *stop = NULL;
 111   char stopc;
 112
 113   if (flag_mri)
 114     stop = mri_comment_field (&stopc);
 115
 116   SKIP_WHITESPACE ();           /* Leading whitespace is part of operand. */
 117
 118   if (current_cframe != NULL && current_cframe->ignoring)
 119     {
 120       operand.X_add_number = 0;
 121       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 122         ++input_line_pointer;
 123     }
 124   else
 125     {
 126       expression (&operand);
 127       if (operand.X_op != O_constant)
 128         as_bad (_("non-constant expression in \".if\" statement"));
 129     }
 130
 131   switch ((operatorT) arg)
 132     {
 133     case O_eq: t = operand.X_add_number == 0; break;
 134     case O_ne: t = operand.X_add_number != 0; break;
 135     case O_lt: t = operand.X_add_number < 0; break;
 136     case O_le: t = operand.X_add_number <= 0; break;
 137     case O_ge: t = operand.X_add_number >= 0; break;
 138     case O_gt: t = operand.X_add_number > 0; break;
 139     default:
 140       abort ();
 141       return;
 142     }
 143
 144   /* If the above error is signaled, this will dispatch
 145      using an undefined result.  No big deal.  */
 146   initialize_cframe (&cframe);
 147   cframe.ignoring = cframe.dead_tree || ! t;
 148   current_cframe = ((struct conditional_frame *)
 149                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 150
 151   if (LISTING_SKIP_COND ()
 152       && cframe.ignoring
 153       && (cframe.previous_cframe == NULL
 154           || ! cframe.previous_cframe->ignoring))
 155     listing_list (2);
 156
 157   if (flag_mri)
 158     mri_comment_end (stop, stopc);
 159
 160   demand_empty_rest_of_line ();
 161 }                               /* s_if() */
 162
 163 /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
 164
 165 static char *
 166 get_mri_string (terminator, len)
 167      int terminator;
 168      int *len;
 169 {
 170   char *ret;
 171   char *s;
 172
 173   SKIP_WHITESPACE ();
 174   s = ret = input_line_pointer;
 175   if (*input_line_pointer == '\'')
 176     {
 177       ++s;
 178       ++input_line_pointer;
 179       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 180         {
 181           *s++ = *input_line_pointer++;
 182           if (s[-1] == '\'')
 183             {
 184               if (*input_line_pointer != '\'')
 185                 break;
 186               ++input_line_pointer;
 187             }
 188         }
 189       SKIP_WHITESPACE ();
 190     }
 191   else
 192     {
 193       while (*input_line_pointer != terminator
 194              && ! is_end_of_line[(unsigned char) *input_line_pointer])
 195         ++input_line_pointer;
 196       s = input_line_pointer;
 197       while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
 198         --s;
 199     }
 200
 201   *len = s - ret;
 202   return ret;
 203 }
 204
 205 /* The MRI IFC and IFNC pseudo-ops.  */
 206
 207 void
 208 s_ifc (arg)
 209      int arg;
 210 {
 211   char *stop = NULL;
 212   char stopc;
 213   char *s1, *s2;
 214   int len1, len2;
 215   int res;
 216   struct conditional_frame cframe;
 217
 218   if (flag_mri)
 219     stop = mri_comment_field (&stopc);
 220
 221   s1 = get_mri_string (',', &len1);
 222
 223   if (*input_line_pointer != ',')
 224     as_bad (_("bad format for ifc or ifnc"));
 225   else
 226     ++input_line_pointer;
 227
 228   s2 = get_mri_string (';', &len2);
 229
 230   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 231
 232   initialize_cframe (&cframe);
 233   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 234   current_cframe = ((struct conditional_frame *)
 235                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 236
 237   if (LISTING_SKIP_COND ()
 238       && cframe.ignoring
 239       && (cframe.previous_cframe == NULL
 240           || ! cframe.previous_cframe->ignoring))
 241     listing_list (2);
 242
 243   if (flag_mri)
 244     mri_comment_end (stop, stopc);
 245
 246   demand_empty_rest_of_line ();
 247 }
 248
 249 void
 250 s_endif (arg)
 251      int arg;
 252 {
 253   struct conditional_frame *hold;
 254
 255   if (current_cframe == NULL)
 256     {
 257       as_bad (_("\".endif\" without \".if\""));
 258     }
 259   else
 260     {
 261       if (LISTING_SKIP_COND ()
 262           && current_cframe->ignoring
 263           && (current_cframe->previous_cframe == NULL
 264               || ! current_cframe->previous_cframe->ignoring))
 265         listing_list (1);
 266
 267       hold = current_cframe;
 268       current_cframe = current_cframe->previous_cframe;
 269       obstack_free (&cond_obstack, hold);
 270     }                           /* if one pop too many */
 271
 272   if (flag_mri)
 273     {
 274       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 275         ++input_line_pointer;
 276     }
 277
 278   demand_empty_rest_of_line ();
 279 }                               /* s_endif() */
 280
 281 void
 282 s_else (arg)
 283      int arg;
 284 {
 285   if (current_cframe == NULL)
 286     {
 287       as_bad (_(".else without matching .if - ignored"));
 288
 289     }
 290   else if (current_cframe->else_seen)
 291     {
 292       as_bad (_("duplicate \"else\" - ignored"));
 293       as_bad_where (current_cframe->else_file_line.file,
 294                     current_cframe->else_file_line.line,
 295                     _("here is the previous \"else\""));
 296       as_bad_where (current_cframe->if_file_line.file,
 297                     current_cframe->if_file_line.line,
 298                     _("here is the previous \"if\""));
 299     }
 300   else
 301     {
 302       as_where (&current_cframe->else_file_line.file,
 303                 &current_cframe->else_file_line.line);
 304
 305       if (!current_cframe->dead_tree)
 306         {
 307           current_cframe->ignoring = !current_cframe->ignoring;
 308           if (LISTING_SKIP_COND ())
 309             {
 310               if (! current_cframe->ignoring)
 311                 listing_list (1);
 312               else
 313                 listing_list (2);
 314             }
 315         }                       /* if not a dead tree */
 316
 317       current_cframe->else_seen = 1;
 318     }                           /* if error else do it */
 319
 320   if (flag_mri)
 321     {
 322       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 323         ++input_line_pointer;
 324     }
 325
 326   demand_empty_rest_of_line ();
 327 }                               /* s_else() */
 328
 329 void
 330 s_ifeqs (arg)
 331      int arg;
 332 {
 333   char *s1, *s2;
 334   int len1, len2;
 335   int res;
 336   struct conditional_frame cframe;
 337
 338   s1 = demand_copy_C_string (&len1);
 339
 340   SKIP_WHITESPACE ();
 341   if (*input_line_pointer != ',')
 342     {
 343       as_bad (_(".ifeqs syntax error"));
 344       ignore_rest_of_line ();
 345       return;
 346     }
 347
 348   ++input_line_pointer;
 349
 350   s2 = demand_copy_C_string (&len2);
 351
 352   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 353
 354   initialize_cframe (&cframe);
 355   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 356   current_cframe = ((struct conditional_frame *)
 357                     obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
 358
 359   if (LISTING_SKIP_COND ()
 360       && cframe.ignoring
 361       && (cframe.previous_cframe == NULL
 362           || ! cframe.previous_cframe->ignoring))
 363     listing_list (2);
 364
 365   demand_empty_rest_of_line ();
 366 }                               /* s_ifeqs() */
 367
 368 int
 369 ignore_input ()
 370 {
 371   char *s;
 372
 373   s = input_line_pointer;
 374
 375   if (flag_m68k_mri
 376 #ifdef NO_PSEUDO_DOT
 377       || 1
 378 #endif
 379       )
 380     {
 381       if (s[-1] != '.')
 382         --s;
 383     }
 384   else
 385     {
 386       if (s[-1] != '.')
 387         return (current_cframe != NULL) && (current_cframe->ignoring);
 388     }
 389
 390   /* We cannot ignore certain pseudo ops.  */
 391   if (((s[0] == 'i'
 392         || s[0] == 'I')
 393        && (!strncasecmp (s, "if", 2)
 394            || !strncasecmp (s, "ifdef", 5)
 395            || !strncasecmp (s, "ifndef", 6)))
 396       || ((s[0] == 'e'
 397            || s[0] == 'E')
 398           && (!strncasecmp (s, "else", 4)
 399               || !strncasecmp (s, "endif", 5)
 400               || !strncasecmp (s, "endc", 4))))
 401     return 0;
 402
 403   return (current_cframe != NULL) && (current_cframe->ignoring);
 404 }                               /* ignore_input() */
 405
 406 static void
 407 initialize_cframe (cframe)
 408      struct conditional_frame *cframe;
 409 {
 410   memset (cframe, 0, sizeof (*cframe));
 411   as_where (&cframe->if_file_line.file,
 412             &cframe->if_file_line.line);
 413   cframe->previous_cframe = current_cframe;
 414   cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
 415   cframe->macro_nest = macro_nest;
 416 }
 417
 418 /* Give an error if a conditional is unterminated inside a macro or
 419    the assembly as a whole.  If NEST is non negative, we are being
 420    called because of the end of a macro expansion.  If NEST is
 421    negative, we are being called at the of the input files.  */
 422
 423 void
 424 cond_finish_check (nest)
 425      int nest;
 426 {
 427   if (current_cframe != NULL && current_cframe->macro_nest >= nest)
 428     {
 429       if (nest >= 0)
 430         as_bad (_("end of macro inside conditional"));
 431       else
 432         as_bad (_("end of file inside conditional"));
 433       as_bad_where (current_cframe->if_file_line.file,
 434                     current_cframe->if_file_line.line,
 435                     _("here is the start of the unterminated conditional"));
 436       if (current_cframe->else_seen)
 437         as_bad_where (current_cframe->else_file_line.file,
 438                       current_cframe->else_file_line.line,
 439                       _("here is the \"else\" of the unterminated conditional"));
 440     }
 441 }
 442
 443 /* This function is called when we exit out of a macro.  We assume
 444    that any conditionals which began within the macro are correctly
 445    nested, and just pop them off the stack.  */
 446
 447 void
 448 cond_exit_macro (nest)
 449      int nest;
 450 {
 451   while (current_cframe != NULL && current_cframe->macro_nest >= nest)
 452     {
 453       struct conditional_frame *hold;
 454
 455       hold = current_cframe;
 456       current_cframe = current_cframe->previous_cframe;
 457       obstack_free (&cond_obstack, hold);
 458     }
 459 }
 460
 461 /* end of cond.c */