gas/input-scrub.c

   1 /* input_scrub.c - Break up input buffers into whole numbers of lines.
   2    Copyright (C) 1987-2023 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       if (multibyte_handling == multibyte_warn)
 390         (void) scan_for_multibyte_characters ((const unsigned char *) p,
 391                                               (const unsigned char *) limit,
 392                                               true /* Generate warnings */);
 393
 394       /* We found a newline in the newly read chars.  */
 395       partial_where = p;
 396       partial_size = limit - p;
 397
 398       /* Save the fragment after that last newline.  */
 399       memcpy (save_source, partial_where, (int) AFTER_SIZE);
 400       memcpy (partial_where, AFTER_STRING, (int) AFTER_SIZE);
 401       return partial_where;
 402
 403     read_more:
 404       /* Didn't find a newline.  Read more text.  */
 405       partial_size = limit - (buffer_start + BEFORE_SIZE);
 406       if (buffer_length - input_file_buffer_size () < partial_size)
 407         {
 408           /* Increase the buffer when it doesn't have room for the
 409              next block of input.  */
 410           buffer_length *= 2;
 411           buffer_start = XRESIZEVEC (char, buffer_start,
 412                                      (buffer_length
 413                                       + BEFORE_SIZE + AFTER_SIZE + 1));
 414         }
 415     }
 416
 417   /* Tell the listing we've finished the file.  */
 418   LISTING_EOF ();
 419
 420   /* If we should pop to another file at EOF, do it.  */
 421   partial_where = NULL;
 422   if (next_saved_file)
 423     *bufp = input_scrub_pop (next_saved_file);
 424
 425   return partial_where;
 426 }
 427 \f
 428 /* The remaining part of this file deals with line numbers, error
 429    messages and so on.  Return TRUE if we opened any file.  */
 430
 431 int
 432 seen_at_least_1_file (void)
 433 {
 434   return (physical_input_file != NULL);
 435 }
 436
 437 void
 438 bump_line_counters (void)
 439 {
 440   if (sb_index == (size_t) -1)
 441     ++physical_input_line;
 442
 443   if (logical_input_line != -1u)
 444     ++logical_input_line;
 445 }
 446 \f
 447 /* Tells us what the new logical line number and file are.
 448    If the line_number is -1, we don't change the current logical line
 449    number.
 450    If fname is NULL, we don't change the current logical file name, unless
 451    bit 3 of flags is set.
 452    Returns nonzero if the filename actually changes.  */
 453
 454 void
 455 new_logical_line_flags (const char *fname, /* DON'T destroy it!  We point to it!  */
 456                         int line_number,
 457                         int flags)
 458 {
 459   switch (flags)
 460     {
 461     case 0:
 462       break;
 463     case 1:
 464       if (line_number != -1)
 465         abort ();
 466       break;
 467     case 1 << 1:
 468     case 1 << 2:
 469       /* FIXME: we could check that include nesting is correct.  */
 470       break;
 471     case 1 << 3:
 472       if (line_number < 0 || fname != NULL)
 473         abort ();
 474       if (next_saved_file == NULL)
 475         fname = physical_input_file;
 476       else if (next_saved_file->logical_input_file)
 477         fname = next_saved_file->logical_input_file;
 478       else
 479         fname = next_saved_file->physical_input_file;
 480       break;
 481     default:
 482       abort ();
 483     }
 484
 485   is_linefile = flags != 1 && (flags != 0 || fname);
 486
 487   if (line_number >= 0)
 488     logical_input_line = line_number;
 489   else if (line_number == -1 && fname && !*fname && (flags & (1 << 2)))
 490     {
 491       logical_input_file = physical_input_file;
 492       logical_input_line = physical_input_line;
 493       fname = NULL;
 494     }
 495
 496   if (fname
 497       && (logical_input_file == NULL
 498           || filename_cmp (logical_input_file, fname)))
 499     logical_input_file = fname;
 500 }
 501
 502 void
 503 new_logical_line (const char *fname, int line_number)
 504 {
 505   new_logical_line_flags (fname, line_number, 0);
 506 }
 507
 508 void
 509 as_report_context (void)
 510 {
 511   const struct input_save *saved = next_saved_file;
 512   enum expansion expansion = from_sb_expansion;
 513   int indent = 1;
 514
 515   if (!macro_nest)
 516     return;
 517
 518   do
 519     {
 520       if (expansion != expanding_macro)
 521         /* Nothing.  */;
 522       else if (saved->logical_input_file != NULL
 523                && saved->logical_input_line != -1u)
 524         as_info_where (saved->logical_input_file, saved->logical_input_line,
 525                        indent, _("macro invoked from here"));
 526       else
 527         as_info_where (saved->physical_input_file, saved->physical_input_line,
 528                        indent, _("macro invoked from here"));
 529
 530       expansion = saved->from_sb_expansion;
 531       ++indent;
 532     }
 533   while ((saved = saved->next_saved_file) != NULL);
 534 }
 535 \f
 536 /* Return the current physical input file name and line number, if known  */
 537
 538 const char *
 539 as_where_physical (unsigned int *linep)
 540 {
 541   if (physical_input_file != NULL)
 542     {
 543       if (linep != NULL)
 544         *linep = physical_input_line;
 545       return physical_input_file;
 546     }
 547
 548   if (linep != NULL)
 549     *linep = 0;
 550   return NULL;
 551 }
 552
 553 /* Return the file name and line number at the top most macro
 554    invocation, unless .file / .line were used inside a macro.  */
 555
 556 const char *
 557 as_where (unsigned int *linep)
 558 {
 559   const char *file = as_where_top (linep);
 560
 561   if (macro_nest && is_linefile)
 562     {
 563       const struct input_save *saved = next_saved_file;
 564       enum expansion expansion = from_sb_expansion;
 565
 566       do
 567         {
 568           if (expansion != expanding_macro)
 569             /* Nothing.  */;
 570           else if (saved->logical_input_file != NULL
 571                    && (linep == NULL || saved->logical_input_line != -1u))
 572             {
 573               if (linep != NULL)
 574                 *linep = saved->logical_input_line;
 575               file = saved->logical_input_file;
 576             }
 577           else if (saved->physical_input_file != NULL)
 578             {
 579               if (linep != NULL)
 580                 *linep = saved->physical_input_line;
 581               file = saved->physical_input_file;
 582             }
 583
 584           expansion = saved->from_sb_expansion;
 585         }
 586       while ((saved = saved->next_saved_file) != NULL);
 587     }
 588
 589   return file;
 590 }
 591
 592 /* Return the current file name and line number.  */
 593
 594 const char *
 595 as_where_top (unsigned int *linep)
 596 {
 597   if (logical_input_file != NULL
 598       && (linep == NULL || logical_input_line != -1u))
 599     {
 600       if (linep != NULL)
 601         *linep = logical_input_line;
 602       return logical_input_file;
 603     }
 604
 605   return as_where_physical (linep);
 606 }