gas/input-scrub.c

   1 /* input_scrub.c - Break up input buffers into whole numbers of lines.
   2    Copyright (C) 1987-2024 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 "filenames.h"
  23 #include "input-file.h"
  24 #include "sb.h"
  25 #include "listing.h"
  26
  27 /*
  28  * O/S independent module to supply buffers of sanitised source code
  29  * to rest of assembler.  We get sanitised input data of arbitrary length.
  30  * We break these buffers on line boundaries, recombine pieces that
  31  * were broken across buffers, and return a buffer of full lines to
  32  * the caller.
  33  * The last partial line begins the next buffer we build and return to caller.
  34  * The buffer returned to caller is preceded by BEFORE_STRING and followed
  35  * by AFTER_STRING, as sentinels. The last character before AFTER_STRING
  36  * is a newline.
  37  * Also looks after line numbers, for e.g. error messages.
  38  */
  39
  40 /*
  41  * We don't care how filthy our buffers are, but our callers assume
  42  * that the following sanitation has already been done.
  43  *
  44  * No comments, reduce a comment to a space.
  45  * Reduce a tab to a space unless it is 1st char of line.
  46  * All multiple tabs and spaces collapsed into 1 char. Tab only
  47  *   legal if 1st char of line.
  48  * # line file statements converted to .line x;.file y; statements.
  49  * Escaped newlines at end of line: remove them but add as many newlines
  50  *   to end of statement as you removed in the middle, to synch line numbers.
  51  */
  52 \f
  53 #define BEFORE_STRING ("\n")
  54 #define AFTER_STRING ("\0")     /* memcpy of 0 chars might choke.  */
  55 #define BEFORE_SIZE (1)
  56 #define AFTER_SIZE  (1)
  57
  58 #ifndef TC_EOL_IN_INSN
  59 #define TC_EOL_IN_INSN(P) 0
  60 #endif
  61
  62 static char *buffer_start;      /*->1st char of full buffer area.  */
  63 static char *partial_where;     /*->after last full line in buffer.  */
  64 static size_t partial_size;     /* >=0. Number of chars in partial line in buffer.  */
  65
  66 /* Because we need AFTER_STRING just after last full line, it clobbers
  67    1st part of partial line. So we preserve 1st part of partial line
  68    here.  */
  69 static char save_source[AFTER_SIZE];
  70
  71 /* The size of the input buffer we concatenate
  72    input_file_give_next_buffer chunks into.  Excludes the BEFORE and
  73    AFTER counts.  */
  74 static size_t buffer_length;
  75
  76 /* The index into an sb structure we are reading from.  -1 if none.  */
  77 static size_t sb_index = -1;
  78
  79 /* If we are reading from an sb structure, this is it.  */
  80 static sb from_sb;
  81
  82 /* Should we do a conditional check on from_sb? */
  83 static enum expansion from_sb_expansion = expanding_none;
  84
  85 /* The number of nested sb structures we have included.  */
  86 int macro_nest;
  87
  88 /* We can have more than one source file open at once, though the info for all
  89    but the latest one are saved off in a struct input_save.  These files remain
  90    open, so we are limited by the number of open files allowed by the
  91    underlying OS. We may also sequentially read more than one source file in an
  92    assembly.  */
  93
  94 /* We must track the physical file and line number for error messages. We also
  95    track a "logical" file and line number corresponding to (C?)  compiler
  96    source line numbers.  Whenever we open a file we must fill in
  97    physical_input_file. So if it is NULL we have not opened any files yet.  */
  98
  99 static const char *physical_input_file;
 100 static const char *logical_input_file;
 101
 102 /* 1-origin line number in a source file.  */
 103 /* A line ends in '\n' or eof.  */
 104 static unsigned int physical_input_line;
 105 static unsigned int logical_input_line;
 106
 107 /* Indicator whether the origin of an update was a .linefile directive. */
 108 static bool is_linefile;
 109
 110 /* Struct used to save the state of the input handler during include files */
 111 struct input_save {
 112   char *              buffer_start;
 113   char *              partial_where;
 114   size_t              partial_size;
 115   char                save_source[AFTER_SIZE];
 116   size_t              buffer_length;
 117   const char *        physical_input_file;
 118   const char *        logical_input_file;
 119   unsigned int        physical_input_line;
 120   unsigned int        logical_input_line;
 121   bool                is_linefile;
 122   size_t              sb_index;
 123   sb                  from_sb;
 124   enum expansion      from_sb_expansion; /* Should we do a conditional check?  */
 125   struct input_save * next_saved_file;  /* Chain of input_saves.  */
 126   char *              input_file_save;  /* Saved state of input routines.  */
 127   char *              saved_position;   /* Caller's saved position in buf.  */
 128 };
 129
 130 static struct input_save *input_scrub_push (char *saved_position);
 131 static char *input_scrub_pop (struct input_save *arg);
 132
 133 /* Saved information about the file that .include'd this one.  When we hit EOF,
 134    we automatically pop to that file.  */
 135
 136 static struct input_save *next_saved_file;
 137
 138 /* Initialize input buffering.  */
 139
 140 static void
 141 input_scrub_reinit (void)
 142 {
 143   input_file_begin ();          /* Reinitialize! */
 144   logical_input_line = -1u;
 145   logical_input_file = NULL;
 146   sb_index = -1;
 147
 148   buffer_length = input_file_buffer_size () * 2;
 149   buffer_start = XNEWVEC (char, BEFORE_SIZE + AFTER_SIZE + 1 + buffer_length);
 150   memcpy (buffer_start, BEFORE_STRING, (int) BEFORE_SIZE);
 151 }
 152
 153 /* Push the state of input reading and scrubbing so that we can #include.
 154    The return value is a 'void *' (fudged for old compilers) to a save
 155    area, which can be restored by passing it to input_scrub_pop().  */
 156
 157 static struct input_save *
 158 input_scrub_push (char *saved_position)
 159 {
 160   struct input_save *saved;
 161
 162   saved = XNEW (struct input_save);
 163
 164   saved->saved_position = saved_position;
 165   saved->buffer_start = buffer_start;
 166   saved->partial_where = partial_where;
 167   saved->partial_size = partial_size;
 168   saved->buffer_length = buffer_length;
 169   saved->physical_input_file = physical_input_file;
 170   saved->logical_input_file = logical_input_file;
 171   saved->physical_input_line = physical_input_line;
 172   saved->logical_input_line = logical_input_line;
 173   saved->is_linefile = is_linefile;
 174   saved->sb_index = sb_index;
 175   saved->from_sb = from_sb;
 176   saved->from_sb_expansion = from_sb_expansion;
 177   memcpy (saved->save_source, save_source, sizeof (save_source));
 178   saved->next_saved_file = next_saved_file;
 179   saved->input_file_save = input_file_push ();
 180
 181   input_scrub_reinit ();
 182
 183   return saved;
 184 }
 185
 186 static char *
 187 input_scrub_pop (struct input_save *saved)
 188 {
 189   char *saved_position;
 190
 191   input_scrub_end ();           /* Finish off old buffer */
 192
 193   input_file_pop (saved->input_file_save);
 194   saved_position = saved->saved_position;
 195   buffer_start = saved->buffer_start;
 196   buffer_length = saved->buffer_length;
 197   physical_input_file = saved->physical_input_file;
 198   logical_input_file = saved->logical_input_file;
 199   physical_input_line = saved->physical_input_line;
 200   logical_input_line = saved->logical_input_line;
 201   is_linefile = saved->is_linefile;
 202   sb_index = saved->sb_index;
 203   from_sb = saved->from_sb;
 204   from_sb_expansion = saved->from_sb_expansion;
 205   partial_where = saved->partial_where;
 206   partial_size = saved->partial_size;
 207   next_saved_file = saved->next_saved_file;
 208   memcpy (save_source, saved->save_source, sizeof (save_source));
 209
 210   free (saved);
 211   return saved_position;
 212 }
 213 \f
 214 void
 215 input_scrub_begin (void)
 216 {
 217   know (strlen (BEFORE_STRING) == BEFORE_SIZE);
 218   know (strlen (AFTER_STRING) == AFTER_SIZE
 219         || (AFTER_STRING[0] == '\0' && AFTER_SIZE == 1));
 220
 221   physical_input_file = NULL;   /* No file read yet.  */
 222   next_saved_file = NULL;       /* At EOF, don't pop to any other file */
 223   macro_nest = 0;
 224   input_scrub_reinit ();
 225   do_scrub_begin (flag_m68k_mri);
 226 }
 227
 228 void
 229 input_scrub_end (void)
 230 {
 231   if (buffer_start)
 232     {
 233       free (buffer_start);
 234       buffer_start = 0;
 235       input_file_end ();
 236     }
 237 }
 238
 239 /* Start reading input from a new file.
 240    Return start of caller's part of buffer.  */
 241
 242 char *
 243 input_scrub_new_file (const char *filename)
 244 {
 245   input_file_open (filename, !flag_no_comments);
 246   physical_input_file = filename[0] ? filename : _("{standard input}");
 247   physical_input_line = 0;
 248
 249   partial_size = 0;
 250   return (buffer_start + BEFORE_SIZE);
 251 }
 252
 253 /* Include a file from the current file.  Save our state, cause it to
 254    be restored on EOF, and begin handling a new file.  Same result as
 255    input_scrub_new_file.  */
 256
 257 char *
 258 input_scrub_include_file (const char *filename, char *position)
 259 {
 260   next_saved_file = input_scrub_push (position);
 261   from_sb_expansion = expanding_none;
 262   return input_scrub_new_file (filename);
 263 }
 264
 265 /* Start getting input from an sb structure.  This is used when
 266    expanding a macro.  */
 267
 268 void
 269 input_scrub_include_sb (sb *from, char *position, enum expansion expansion)
 270 {
 271   int newline;
 272
 273   if (macro_nest > max_macro_nest)
 274     as_fatal (_("macros nested too deeply"));
 275   ++macro_nest;
 276
 277 #ifdef md_macro_start
 278   if (expansion == expanding_macro)
 279     {
 280       md_macro_start ();
 281     }
 282 #endif
 283
 284   next_saved_file = input_scrub_push (position);
 285
 286   /* Allocate sufficient space: from->len plus optional newline
 287      plus two ".linefile " directives, plus a little more for other
 288      expansion.  */
 289   newline = from->len >= 1 && from->ptr[0] != '\n';
 290   sb_build (&from_sb, from->len + newline + 2 * sizeof (".linefile") + 30);
 291   from_sb_expansion = expansion;
 292   if (newline)
 293     {
 294       /* Add the sentinel required by read.c.  */
 295       sb_add_char (&from_sb, '\n');
 296     }
 297   sb_scrub_and_add_sb (&from_sb, from);
 298
 299   /* Make sure the parser looks at defined contents when it scans for
 300      e.g. end-of-line at the end of a macro.  */
 301   sb_terminate (&from_sb);
 302
 303   sb_index = 1;
 304
 305   /* These variables are reset by input_scrub_push.  Restore them
 306      since we are, after all, still at the same point in the file.  */
 307   logical_input_line = next_saved_file->logical_input_line;
 308   logical_input_file = next_saved_file->logical_input_file;
 309 }
 310
 311 void
 312 input_scrub_close (void)
 313 {
 314   input_file_close ();
 315   physical_input_line = 0;
 316   logical_input_line = -1u;
 317 }
 318
 319 char *
 320 input_scrub_next_buffer (char **bufp)
 321 {
 322   char *limit;          /*->just after last char of buffer.  */
 323
 324   if (sb_index != (size_t) -1)
 325     {
 326       if (sb_index >= from_sb.len)
 327         {
 328           sb_kill (&from_sb);
 329           if (from_sb_expansion == expanding_macro)
 330             {
 331               cond_finish_check (macro_nest);
 332 #ifdef md_macro_end
 333               /* Allow the target to clean up per-macro expansion
 334                  data.  */
 335               md_macro_end ();
 336 #endif
 337             }
 338           --macro_nest;
 339           partial_where = NULL;
 340           partial_size = 0;
 341           if (next_saved_file != NULL)
 342             *bufp = input_scrub_pop (next_saved_file);
 343           return partial_where;
 344         }
 345
 346       partial_where = from_sb.ptr + from_sb.len;
 347       partial_size = 0;
 348       *bufp = from_sb.ptr + sb_index;
 349       sb_index = from_sb.len;
 350       return partial_where;
 351     }
 352
 353   if (partial_size)
 354     {
 355       memmove (buffer_start + BEFORE_SIZE, partial_where, partial_size);
 356       memcpy (buffer_start + BEFORE_SIZE, save_source, AFTER_SIZE);
 357     }
 358
 359   while (1)
 360     {
 361       char *p;
 362       char *start = buffer_start + BEFORE_SIZE + partial_size;
 363
 364       *bufp = buffer_start + BEFORE_SIZE;
 365       limit = input_file_give_next_buffer (start);
 366       if (!limit)
 367         {
 368           if (!partial_size)
 369             /* End of this file.  */
 370             break;
 371
 372           as_warn (_("end of file not at end of a line; newline inserted"));
 373           p = buffer_start + BEFORE_SIZE + partial_size;
 374           *p++ = '\n';
 375           limit = p;
 376         }
 377       else
 378         {
 379           /* Terminate the buffer to avoid confusing TC_EOL_IN_INSN.  */
 380           *limit = '\0';
 381
 382           /* Find last newline.  */
 383           for (p = limit - 1; *p != '\n' || TC_EOL_IN_INSN (p); --p)
 384             if (p < start)
 385               goto read_more;
 386           ++p;
 387         }
 388
 389       /* We found a newline in the newly read chars.  */
 390       partial_where = p;
 391       partial_size = limit - p;
 392
 393       /* Save the fragment after that last newline.  */
 394       memcpy (save_source, partial_where, (int) AFTER_SIZE);
 395       memcpy (partial_where, AFTER_STRING, (int) AFTER_SIZE);
 396       return partial_where;
 397
 398     read_more:
 399       /* Didn't find a newline.  Read more text.  */
 400       partial_size = limit - (buffer_start + BEFORE_SIZE);
 401       if (buffer_length - input_file_buffer_size () < partial_size)
 402         {
 403           /* Increase the buffer when it doesn't have room for the
 404              next block of input.  */
 405           buffer_length *= 2;
 406           buffer_start = XRESIZEVEC (char, buffer_start,
 407                                      (buffer_length
 408                                       + BEFORE_SIZE + AFTER_SIZE + 1));
 409         }
 410     }
 411
 412   /* Tell the listing we've finished the file.  */
 413   LISTING_EOF ();
 414
 415   /* If we should pop to another file at EOF, do it.  */
 416   partial_where = NULL;
 417   if (next_saved_file)
 418     *bufp = input_scrub_pop (next_saved_file);
 419
 420   return partial_where;
 421 }
 422 \f
 423 /* The remaining part of this file deals with line numbers, error
 424    messages and so on.  Return TRUE if we opened any file.  */
 425
 426 int
 427 seen_at_least_1_file (void)
 428 {
 429   return (physical_input_file != NULL);
 430 }
 431
 432 void
 433 bump_line_counters (void)
 434 {
 435   if (sb_index == (size_t) -1)
 436     ++physical_input_line;
 437
 438   if (logical_input_line != -1u)
 439     ++logical_input_line;
 440 }
 441 \f
 442 /* Tells us what the new logical line number and file are.
 443    If the line_number is -1, we don't change the current logical line
 444    number.
 445    If fname is NULL, we don't change the current logical file name, unless
 446    bit 3 of flags is set.
 447    Returns nonzero if the filename actually changes.  */
 448
 449 void
 450 new_logical_line_flags (const char *fname, /* DON'T destroy it!  We point to it!  */
 451                         int line_number,
 452                         int flags)
 453 {
 454   switch (flags)
 455     {
 456     case 0:
 457       break;
 458     case 1:
 459       if (line_number != -1)
 460         abort ();
 461       break;
 462     case 1 << 1:
 463     case 1 << 2:
 464       /* FIXME: we could check that include nesting is correct.  */
 465       break;
 466     case 1 << 3:
 467       if (line_number < 0 || fname != NULL)
 468         abort ();
 469       if (next_saved_file == NULL)
 470         fname = physical_input_file;
 471       else if (next_saved_file->logical_input_file)
 472         fname = next_saved_file->logical_input_file;
 473       else
 474         fname = next_saved_file->physical_input_file;
 475       break;
 476     default:
 477       abort ();
 478     }
 479
 480   is_linefile = flags != 1 && (flags != 0 || fname);
 481
 482   if (line_number >= 0)
 483     logical_input_line = line_number;
 484   else if (line_number == -1 && fname && !*fname && (flags & (1 << 2)))
 485     {
 486       logical_input_file = physical_input_file;
 487       logical_input_line = physical_input_line;
 488       fname = NULL;
 489     }
 490
 491   if (fname
 492       && (logical_input_file == NULL
 493           || filename_cmp (logical_input_file, fname)))
 494     logical_input_file = fname;
 495 }
 496
 497 void
 498 new_logical_line (const char *fname, int line_number)
 499 {
 500   new_logical_line_flags (fname, line_number, 0);
 501 }
 502
 503 void
 504 as_report_context (void)
 505 {
 506   const struct input_save *saved = next_saved_file;
 507   enum expansion expansion = from_sb_expansion;
 508   int indent = 1;
 509
 510   if (!macro_nest)
 511     return;
 512
 513   do
 514     {
 515       if (expansion != expanding_macro)
 516         /* Nothing.  */;
 517       else if (saved->logical_input_file != NULL
 518                && saved->logical_input_line != -1u)
 519         as_info_where (saved->logical_input_file, saved->logical_input_line,
 520                        indent, _("macro invoked from here"));
 521       else
 522         as_info_where (saved->physical_input_file, saved->physical_input_line,
 523                        indent, _("macro invoked from here"));
 524
 525       expansion = saved->from_sb_expansion;
 526       ++indent;
 527     }
 528   while ((saved = saved->next_saved_file) != NULL);
 529 }
 530 \f
 531 /* Return the current physical input file name and line number, if known  */
 532
 533 const char *
 534 as_where_physical (unsigned int *linep)
 535 {
 536   if (physical_input_file != NULL)
 537     {
 538       if (linep != NULL)
 539         *linep = physical_input_line;
 540       return physical_input_file;
 541     }
 542
 543   if (linep != NULL)
 544     *linep = 0;
 545   return NULL;
 546 }
 547
 548 /* Return the file name and line number at the top most macro
 549    invocation, unless .file / .line were used inside a macro.  */
 550
 551 const char *
 552 as_where (unsigned int *linep)
 553 {
 554   const char *file = as_where_top (linep);
 555
 556   if (macro_nest && is_linefile)
 557     {
 558       const struct input_save *saved = next_saved_file;
 559       enum expansion expansion = from_sb_expansion;
 560
 561       do
 562         {
 563           if (expansion != expanding_macro)
 564             /* Nothing.  */;
 565           else if (saved->logical_input_file != NULL
 566                    && (linep == NULL || saved->logical_input_line != -1u))
 567             {
 568               if (linep != NULL)
 569                 *linep = saved->logical_input_line;
 570               file = saved->logical_input_file;
 571             }
 572           else if (saved->physical_input_file != NULL)
 573             {
 574               if (linep != NULL)
 575                 *linep = saved->physical_input_line;
 576               file = saved->physical_input_file;
 577             }
 578
 579           expansion = saved->from_sb_expansion;
 580         }
 581       while ((saved = saved->next_saved_file) != NULL);
 582     }
 583
 584   return file;
 585 }
 586
 587 /* Return the current file name and line number.  */
 588
 589 const char *
 590 as_where_top (unsigned int *linep)
 591 {
 592   if (logical_input_file != NULL
 593       && (linep == NULL || logical_input_line != -1u))
 594     {
 595       if (linep != NULL)
 596         *linep = logical_input_line;
 597       return logical_input_file;
 598     }
 599
 600   return as_where_physical (linep);
 601 }