gas/cond.c

   1 /* cond.c - conditional assembly pseudo-ops, and .include
   2    Copyright (C) 1990-2020 Free Software Foundation, Inc.
   3
   4    This file is part of GAS, the GNU Assembler.
   5
   6    GAS is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    GAS is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GAS; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  19    02110-1301, USA.  */
  20
  21 #include "as.h"
  22 #include "sb.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 {
  33   const 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 {
  42   /* The source file & line number of the "if".  */
  43   struct file_line if_file_line;
  44   /* The source file & line of the "else".  */
  45   struct file_line else_file_line;
  46   /* The previous conditional.  */
  47   struct conditional_frame *previous_cframe;
  48   /* Have we seen an else yet?  */
  49   int else_seen;
  50   /* Whether we are currently ignoring input.  */
  51   int ignoring;
  52   /* Whether a conditional at a higher level is ignoring input.
  53      Set also when a branch of an "if .. elseif .." tree has matched
  54      to prevent further matches.  */
  55   int dead_tree;
  56   /* Macro nesting level at which this conditional was created.  */
  57   int macro_nest;
  58 };
  59
  60 static void initialize_cframe (struct conditional_frame *cframe);
  61 static char *get_mri_string (int, int *);
  62
  63 static struct conditional_frame *current_cframe = NULL;
  64
  65 /* Performs the .ifdef (test_defined == 1) and
  66    the .ifndef (test_defined == 0) pseudo op.  */
  67
  68 void
  69 s_ifdef (int test_defined)
  70 {
  71   /* Points to name of symbol.  */
  72   char *name;
  73   /* Points to symbol.  */
  74   symbolS *symbolP;
  75   struct conditional_frame cframe;
  76   char c;
  77
  78   /* Leading whitespace is part of operand.  */
  79   SKIP_WHITESPACE ();
  80   name = input_line_pointer;
  81
  82   if (!is_name_beginner (*name) && *name != '"')
  83     {
  84       as_bad (_("invalid identifier for \".ifdef\""));
  85       obstack_1grow (&cond_obstack, 0);
  86       ignore_rest_of_line ();
  87       return;
  88     }
  89
  90   c = get_symbol_name (& name);
  91   symbolP = symbol_find (name);
  92   (void) restore_line_pointer (c);
  93
  94   initialize_cframe (&cframe);
  95
  96   if (cframe.dead_tree)
  97     cframe.ignoring = 1;
  98   else
  99     {
 100       int is_defined;
 101
 102       /* Use the same definition of 'defined' as .equiv so that a symbol
 103          which has been referenced but not yet given a value/address is
 104          considered to be undefined.  */
 105       is_defined =
 106         symbolP != NULL
 107         && (S_IS_DEFINED (symbolP) || symbol_equated_p (symbolP))
 108         && S_GET_SEGMENT (symbolP) != reg_section;
 109
 110       cframe.ignoring = ! (test_defined ^ is_defined);
 111     }
 112
 113   current_cframe =
 114     (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
 115   memcpy (current_cframe, &cframe, sizeof cframe);
 116
 117   if (LISTING_SKIP_COND ()
 118       && cframe.ignoring
 119       && (cframe.previous_cframe == NULL
 120           || ! cframe.previous_cframe->ignoring))
 121     listing_list (2);
 122
 123   demand_empty_rest_of_line ();
 124 }
 125
 126 void
 127 s_if (int arg)
 128 {
 129   expressionS operand;
 130   struct conditional_frame cframe;
 131   int t;
 132   char *stop = NULL;
 133   char stopc = 0;
 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_and_evaluate (&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 =
 172     (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
 173   memcpy (current_cframe, & cframe, sizeof cframe);
 174
 175   if (LISTING_SKIP_COND ()
 176       && cframe.ignoring
 177       && (cframe.previous_cframe == NULL
 178           || ! cframe.previous_cframe->ignoring))
 179     listing_list (2);
 180
 181   if (flag_mri)
 182     mri_comment_end (stop, stopc);
 183
 184   demand_empty_rest_of_line ();
 185 }
 186
 187 /* Performs the .ifb (test_blank == 1) and
 188    the .ifnb (test_blank == 0) pseudo op.  */
 189
 190 void
 191 s_ifb (int test_blank)
 192 {
 193   struct conditional_frame cframe;
 194
 195   initialize_cframe (&cframe);
 196
 197   if (cframe.dead_tree)
 198     cframe.ignoring = 1;
 199   else
 200     {
 201       int is_eol;
 202
 203       SKIP_WHITESPACE ();
 204       is_eol = is_end_of_line[(unsigned char) *input_line_pointer];
 205       cframe.ignoring = (test_blank == !is_eol);
 206     }
 207
 208   current_cframe =
 209     (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
 210   memcpy (current_cframe, &cframe, sizeof cframe);
 211
 212   if (LISTING_SKIP_COND ()
 213       && cframe.ignoring
 214       && (cframe.previous_cframe == NULL
 215           || ! cframe.previous_cframe->ignoring))
 216     listing_list (2);
 217
 218   ignore_rest_of_line ();
 219 }
 220
 221 /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
 222
 223 static char *
 224 get_mri_string (int terminator, int *len)
 225 {
 226   char *ret;
 227   char *s;
 228
 229   SKIP_WHITESPACE ();
 230   s = ret = input_line_pointer;
 231   if (*input_line_pointer == '\'')
 232     {
 233       ++s;
 234       ++input_line_pointer;
 235       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 236         {
 237           *s++ = *input_line_pointer++;
 238           if (s[-1] == '\'')
 239             {
 240               if (*input_line_pointer != '\'')
 241                 break;
 242               ++input_line_pointer;
 243             }
 244         }
 245       SKIP_WHITESPACE ();
 246     }
 247   else
 248     {
 249       while (*input_line_pointer != terminator
 250              && ! is_end_of_line[(unsigned char) *input_line_pointer])
 251         ++input_line_pointer;
 252       s = input_line_pointer;
 253       while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
 254         --s;
 255     }
 256
 257   *len = s - ret;
 258   return ret;
 259 }
 260
 261 /* The MRI IFC and IFNC pseudo-ops.  */
 262
 263 void
 264 s_ifc (int arg)
 265 {
 266   char *stop = NULL;
 267   char stopc = 0;
 268   char *s1, *s2;
 269   int len1, len2;
 270   int res;
 271   struct conditional_frame cframe;
 272
 273   if (flag_mri)
 274     stop = mri_comment_field (&stopc);
 275
 276   s1 = get_mri_string (',', &len1);
 277
 278   if (*input_line_pointer != ',')
 279     as_bad (_("bad format for ifc or ifnc"));
 280   else
 281     ++input_line_pointer;
 282
 283   s2 = get_mri_string (';', &len2);
 284
 285   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 286
 287   initialize_cframe (&cframe);
 288   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 289   current_cframe =
 290     (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
 291   memcpy (current_cframe, &cframe, sizeof cframe);
 292
 293  if (LISTING_SKIP_COND ()
 294       && cframe.ignoring
 295       && (cframe.previous_cframe == NULL
 296           || ! cframe.previous_cframe->ignoring))
 297     listing_list (2);
 298
 299   if (flag_mri)
 300     mri_comment_end (stop, stopc);
 301
 302   demand_empty_rest_of_line ();
 303 }
 304
 305 void
 306 s_elseif (int arg)
 307 {
 308   if (current_cframe == NULL)
 309     {
 310       as_bad (_("\".elseif\" without matching \".if\""));
 311     }
 312   else if (current_cframe->else_seen)
 313     {
 314       as_bad (_("\".elseif\" after \".else\""));
 315       as_bad_where (current_cframe->else_file_line.file,
 316                     current_cframe->else_file_line.line,
 317                     _("here is the previous \".else\""));
 318       as_bad_where (current_cframe->if_file_line.file,
 319                     current_cframe->if_file_line.line,
 320                     _("here is the previous \".if\""));
 321     }
 322   else
 323     {
 324       current_cframe->else_file_line.file
 325         = as_where (&current_cframe->else_file_line.line);
 326
 327       current_cframe->dead_tree |= !current_cframe->ignoring;
 328       current_cframe->ignoring = current_cframe->dead_tree;
 329     }
 330
 331   if (current_cframe == NULL || current_cframe->ignoring)
 332     {
 333       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 334         ++input_line_pointer;
 335
 336       if (current_cframe == NULL)
 337         return;
 338     }
 339   else
 340     {
 341       expressionS operand;
 342       int t;
 343
 344       /* Leading whitespace is part of operand.  */
 345       SKIP_WHITESPACE ();
 346
 347       expression_and_evaluate (&operand);
 348       if (operand.X_op != O_constant)
 349         as_bad (_("non-constant expression in \".elseif\" statement"));
 350
 351       switch ((operatorT) arg)
 352         {
 353         case O_eq: t = operand.X_add_number == 0; break;
 354         case O_ne: t = operand.X_add_number != 0; break;
 355         case O_lt: t = operand.X_add_number < 0; break;
 356         case O_le: t = operand.X_add_number <= 0; break;
 357         case O_ge: t = operand.X_add_number >= 0; break;
 358         case O_gt: t = operand.X_add_number > 0; break;
 359         default:
 360           abort ();
 361           return;
 362         }
 363
 364       current_cframe->ignoring = current_cframe->dead_tree || ! t;
 365     }
 366
 367   if (LISTING_SKIP_COND ()
 368       && (current_cframe->previous_cframe == NULL
 369           || ! current_cframe->previous_cframe->ignoring))
 370     {
 371       if (! current_cframe->ignoring)
 372         listing_list (1);
 373       else
 374         listing_list (2);
 375     }
 376
 377   demand_empty_rest_of_line ();
 378 }
 379
 380 void
 381 s_endif (int arg ATTRIBUTE_UNUSED)
 382 {
 383   struct conditional_frame *hold;
 384
 385   if (current_cframe == NULL)
 386     {
 387       as_bad (_("\".endif\" without \".if\""));
 388     }
 389   else
 390     {
 391       if (LISTING_SKIP_COND ()
 392           && current_cframe->ignoring
 393           && (current_cframe->previous_cframe == NULL
 394               || ! current_cframe->previous_cframe->ignoring))
 395         listing_list (1);
 396
 397       hold = current_cframe;
 398       current_cframe = current_cframe->previous_cframe;
 399       obstack_free (&cond_obstack, hold);
 400     }                           /* if one pop too many */
 401
 402   if (flag_mri)
 403     {
 404       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 405         ++input_line_pointer;
 406     }
 407
 408   demand_empty_rest_of_line ();
 409 }
 410
 411 void
 412 s_else (int arg ATTRIBUTE_UNUSED)
 413 {
 414   if (current_cframe == NULL)
 415     {
 416       as_bad (_("\".else\" without matching \".if\""));
 417     }
 418   else if (current_cframe->else_seen)
 419     {
 420       as_bad (_("duplicate \".else\""));
 421       as_bad_where (current_cframe->else_file_line.file,
 422                     current_cframe->else_file_line.line,
 423                     _("here is the previous \".else\""));
 424       as_bad_where (current_cframe->if_file_line.file,
 425                     current_cframe->if_file_line.line,
 426                     _("here is the previous \".if\""));
 427     }
 428   else
 429     {
 430       current_cframe->else_file_line.file
 431         = as_where (&current_cframe->else_file_line.line);
 432
 433       current_cframe->ignoring =
 434         current_cframe->dead_tree | !current_cframe->ignoring;
 435
 436       if (LISTING_SKIP_COND ()
 437           && (current_cframe->previous_cframe == NULL
 438               || ! current_cframe->previous_cframe->ignoring))
 439         {
 440           if (! current_cframe->ignoring)
 441             listing_list (1);
 442           else
 443             listing_list (2);
 444         }
 445
 446       current_cframe->else_seen = 1;
 447     }
 448
 449   if (flag_mri)
 450     {
 451       while (! is_end_of_line[(unsigned char) *input_line_pointer])
 452         ++input_line_pointer;
 453     }
 454
 455   demand_empty_rest_of_line ();
 456 }
 457
 458 void
 459 s_ifeqs (int arg)
 460 {
 461   char *s1, *s2;
 462   int len1, len2;
 463   int res;
 464   struct conditional_frame cframe;
 465
 466   s1 = demand_copy_C_string (&len1);
 467
 468   SKIP_WHITESPACE ();
 469   if (*input_line_pointer != ',')
 470     {
 471       as_bad (_(".ifeqs syntax error"));
 472       ignore_rest_of_line ();
 473       return;
 474     }
 475
 476   ++input_line_pointer;
 477
 478   s2 = demand_copy_C_string (&len2);
 479
 480   res = len1 == len2 && strncmp (s1, s2, len1) == 0;
 481
 482   initialize_cframe (&cframe);
 483   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
 484   current_cframe =
 485     (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
 486   memcpy (current_cframe, &cframe, sizeof cframe);
 487
 488   if (LISTING_SKIP_COND ()
 489       && cframe.ignoring
 490       && (cframe.previous_cframe == NULL
 491           || ! cframe.previous_cframe->ignoring))
 492     listing_list (2);
 493
 494   demand_empty_rest_of_line ();
 495 }
 496
 497 int
 498 ignore_input (void)
 499 {
 500   char *s;
 501
 502   s = input_line_pointer;
 503
 504   if (NO_PSEUDO_DOT || flag_m68k_mri)
 505     {
 506       if (s[-1] != '.')
 507         --s;
 508     }
 509   else
 510     {
 511       if (s[-1] != '.')
 512         return (current_cframe != NULL) && (current_cframe->ignoring);
 513     }
 514
 515   /* We cannot ignore certain pseudo ops.  */
 516   if (((s[0] == 'i'
 517         || s[0] == 'I')
 518        && (!strncasecmp (s, "if", 2)
 519            || !strncasecmp (s, "ifdef", 5)
 520            || !strncasecmp (s, "ifndef", 6)))
 521       || ((s[0] == 'e'
 522            || s[0] == 'E')
 523           && (!strncasecmp (s, "else", 4)
 524               || !strncasecmp (s, "endif", 5)
 525               || !strncasecmp (s, "endc", 4))))
 526     return 0;
 527
 528   return (current_cframe != NULL) && (current_cframe->ignoring);
 529 }
 530
 531 static void
 532 initialize_cframe (struct conditional_frame *cframe)
 533 {
 534   memset (cframe, 0, sizeof (*cframe));
 535   cframe->if_file_line.file
 536             = as_where (&cframe->if_file_line.line);
 537   cframe->previous_cframe = current_cframe;
 538   cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
 539   cframe->macro_nest = macro_nest;
 540 }
 541
 542 /* Give an error if a conditional is unterminated inside a macro or
 543    the assembly as a whole.  If NEST is non negative, we are being
 544    called because of the end of a macro expansion.  If NEST is
 545    negative, we are being called at the of the input files.  */
 546
 547 void
 548 cond_finish_check (int nest)
 549 {
 550   if (current_cframe != NULL && current_cframe->macro_nest >= nest)
 551     {
 552       if (nest >= 0)
 553         as_bad (_("end of macro inside conditional"));
 554       else
 555         as_bad (_("end of file inside conditional"));
 556
 557       as_bad_where (current_cframe->if_file_line.file,
 558                     current_cframe->if_file_line.line,
 559                     _("here is the start of the unterminated conditional"));
 560       if (current_cframe->else_seen)
 561         as_bad_where (current_cframe->else_file_line.file,
 562                       current_cframe->else_file_line.line,
 563                       _("here is the \"else\" of the unterminated conditional"));
 564     }
 565 }
 566
 567 /* This function is called when we exit out of a macro.  We assume
 568    that any conditionals which began within the macro are correctly
 569    nested, and just pop them off the stack.  */
 570
 571 void
 572 cond_exit_macro (int nest)
 573 {
 574   while (current_cframe != NULL && current_cframe->macro_nest >= nest)
 575     {
 576       struct conditional_frame *hold;
 577
 578       hold = current_cframe;
 579       current_cframe = current_cframe->previous_cframe;
 580       obstack_free (&cond_obstack, hold);
 581     }
 582 }