gas/input-scrub.c

   1 /* input_scrub.c - Break up input buffers into whole numbers of lines.
   2    Copyright (C) 1987-2019 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 int from_sb_is_expansion = 1;
  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 int logical_input_line;
 106
 107 /* Struct used to save the state of the input handler during include files */
 108 struct input_save {
 109   char *              buffer_start;
 110   char *              partial_where;
 111   size_t              partial_size;
 112   char                save_source[AFTER_SIZE];
 113   size_t              buffer_length;
 114   const char *              physical_input_file;
 115   const char *              logical_input_file;
 116   unsigned int        physical_input_line;
 117   int                 logical_input_line;
 118   size_t              sb_index;
 119   sb                  from_sb;
 120   int                 from_sb_is_expansion; /* Should we do a conditional check?  */
 121   struct input_save * next_saved_file;  /* Chain of input_saves.  */
 122   char *              input_file_save;  /* Saved state of input routines.  */
 123   char *              saved_position;   /* Caller's saved position in buf.  */
 124 };
 125
 126 static struct input_save *input_scrub_push (char *saved_position);
 127 static char *input_scrub_pop (struct input_save *arg);
 128
 129 /* Saved information about the file that .include'd this one.  When we hit EOF,
 130    we automatically pop to that file.  */
 131
 132 static struct input_save *next_saved_file;
 133
 134 /* Initialize input buffering.  */
 135
 136 static void
 137 input_scrub_reinit (void)
 138 {
 139   input_file_begin ();          /* Reinitialize! */
 140   logical_input_line = -1;
 141   logical_input_file = NULL;
 142
 143   buffer_length = input_file_buffer_size () * 2;
 144   buffer_start = XNEWVEC (char, BEFORE_SIZE + AFTER_SIZE + 1 + buffer_length);
 145   memcpy (buffer_start, BEFORE_STRING, (int) BEFORE_SIZE);
 146 }
 147
 148 /* Push the state of input reading and scrubbing so that we can #include.
 149    The return value is a 'void *' (fudged for old compilers) to a save
 150    area, which can be restored by passing it to input_scrub_pop().  */
 151
 152 static struct input_save *
 153 input_scrub_push (char *saved_position)
 154 {
 155   struct input_save *saved;
 156
 157   saved = XNEW (struct input_save);
 158
 159   saved->saved_position = saved_position;
 160   saved->buffer_start = buffer_start;
 161   saved->partial_where = partial_where;
 162   saved->partial_size = partial_size;
 163   saved->buffer_length = buffer_length;
 164   saved->physical_input_file = physical_input_file;
 165   saved->logical_input_file = logical_input_file;
 166   saved->physical_input_line = physical_input_line;
 167   saved->logical_input_line = logical_input_line;
 168   saved->sb_index = sb_index;
 169   saved->from_sb = from_sb;
 170   saved->from_sb_is_expansion = from_sb_is_expansion;
 171   memcpy (saved->save_source, save_source, sizeof (save_source));
 172   saved->next_saved_file = next_saved_file;
 173   saved->input_file_save = input_file_push ();
 174
 175   sb_index = -1;
 176
 177   input_scrub_reinit ();
 178
 179   return saved;
 180 }
 181
 182 static char *
 183 input_scrub_pop (struct input_save *saved)
 184 {
 185   char *saved_position;
 186
 187   input_scrub_end ();           /* Finish off old buffer */
 188
 189   input_file_pop (saved->input_file_save);
 190   saved_position = saved->saved_position;
 191   buffer_start = saved->buffer_start;
 192   buffer_length = saved->buffer_length;
 193   physical_input_file = saved->physical_input_file;
 194   logical_input_file = saved->logical_input_file;
 195   physical_input_line = saved->physical_input_line;
 196   logical_input_line = saved->logical_input_line;
 197   sb_index = saved->sb_index;
 198   from_sb = saved->from_sb;
 199   from_sb_is_expansion = saved->from_sb_is_expansion;
 200   partial_where = saved->partial_where;
 201   partial_size = saved->partial_size;
 202   next_saved_file = saved->next_saved_file;
 203   memcpy (save_source, saved->save_source, sizeof (save_source));
 204
 205   free (saved);
 206   return saved_position;
 207 }
 208 \f
 209 void
 210 input_scrub_begin (void)
 211 {
 212   know (strlen (BEFORE_STRING) == BEFORE_SIZE);
 213   know (strlen (AFTER_STRING) == AFTER_SIZE
 214         || (AFTER_STRING[0] == '\0' && AFTER_SIZE == 1));
 215
 216   physical_input_file = NULL;   /* No file read yet.  */
 217   next_saved_file = NULL;       /* At EOF, don't pop to any other file */
 218   input_scrub_reinit ();
 219   do_scrub_begin (flag_m68k_mri);
 220 }
 221
 222 void
 223 input_scrub_end (void)
 224 {
 225   if (buffer_start)
 226     {
 227       free (buffer_start);
 228       buffer_start = 0;
 229       input_file_end ();
 230     }
 231 }
 232
 233 /* Start reading input from a new file.
 234    Return start of caller's part of buffer.  */
 235
 236 char *
 237 input_scrub_new_file (const char *filename)
 238 {
 239   input_file_open (filename, !flag_no_comments);
 240   physical_input_file = filename[0] ? filename : _("{standard input}");
 241   physical_input_line = 0;
 242
 243   partial_size = 0;
 244   return (buffer_start + BEFORE_SIZE);
 245 }
 246
 247 /* Include a file from the current file.  Save our state, cause it to
 248    be restored on EOF, and begin handling a new file.  Same result as
 249    input_scrub_new_file.  */
 250
 251 char *
 252 input_scrub_include_file (const char *filename, char *position)
 253 {
 254   next_saved_file = input_scrub_push (position);
 255   return input_scrub_new_file (filename);
 256 }
 257
 258 /* Start getting input from an sb structure.  This is used when
 259    expanding a macro.  */
 260
 261 void
 262 input_scrub_include_sb (sb *from, char *position, int is_expansion)
 263 {
 264   int newline;
 265
 266   if (macro_nest > max_macro_nest)
 267     as_fatal (_("macros nested too deeply"));
 268   ++macro_nest;
 269
 270 #ifdef md_macro_start
 271   if (is_expansion)
 272     {
 273       md_macro_start ();
 274     }
 275 #endif
 276
 277   next_saved_file = input_scrub_push (position);
 278
 279   /* Allocate sufficient space: from->len + optional newline.  */
 280   newline = from->len >= 1 && from->ptr[0] != '\n';
 281   sb_build (&from_sb, from->len + newline);
 282   from_sb_is_expansion = is_expansion;
 283   if (newline)
 284     {
 285       /* Add the sentinel required by read.c.  */
 286       sb_add_char (&from_sb, '\n');
 287     }
 288   sb_scrub_and_add_sb (&from_sb, from);
 289
 290   /* Make sure the parser looks at defined contents when it scans for
 291      e.g. end-of-line at the end of a macro.  */
 292   sb_terminate (&from_sb);
 293
 294   sb_index = 1;
 295
 296   /* These variables are reset by input_scrub_push.  Restore them
 297      since we are, after all, still at the same point in the file.  */
 298   logical_input_line = next_saved_file->logical_input_line;
 299   logical_input_file = next_saved_file->logical_input_file;
 300 }
 301
 302 void
 303 input_scrub_close (void)
 304 {
 305   input_file_close ();
 306   physical_input_line = 0;
 307   logical_input_line = -1;
 308 }
 309
 310 char *
 311 input_scrub_next_buffer (char **bufp)
 312 {
 313   char *limit;          /*->just after last char of buffer.  */
 314
 315   if (sb_index != (size_t) -1)
 316     {
 317       if (sb_index >= from_sb.len)
 318         {
 319           sb_kill (&from_sb);
 320           if (from_sb_is_expansion)
 321             {
 322               cond_finish_check (macro_nest);
 323 #ifdef md_macro_end
 324               /* Allow the target to clean up per-macro expansion
 325                  data.  */
 326               md_macro_end ();
 327 #endif
 328             }
 329           --macro_nest;
 330           partial_where = NULL;
 331           partial_size = 0;
 332           if (next_saved_file != NULL)
 333             *bufp = input_scrub_pop (next_saved_file);
 334           return partial_where;
 335         }
 336
 337       partial_where = from_sb.ptr + from_sb.len;
 338       partial_size = 0;
 339       *bufp = from_sb.ptr + sb_index;
 340       sb_index = from_sb.len;
 341       return partial_where;
 342     }
 343
 344   if (partial_size)
 345     {
 346       memmove (buffer_start + BEFORE_SIZE, partial_where, partial_size);
 347       memcpy (buffer_start + BEFORE_SIZE, save_source, AFTER_SIZE);
 348     }
 349
 350   while (1)
 351     {
 352       char *p;
 353       char *start = buffer_start + BEFORE_SIZE + partial_size;
 354
 355       *bufp = buffer_start + BEFORE_SIZE;
 356       limit = input_file_give_next_buffer (start);
 357       if (!limit)
 358         {
 359           if (!partial_size)
 360             /* End of this file.  */
 361             break;
 362
 363           as_warn (_("end of file not at end of a line; newline inserted"));
 364           p = buffer_start + BEFORE_SIZE + partial_size;
 365           *p++ = '\n';
 366           limit = p;
 367         }
 368       else
 369         {
 370           /* Terminate the buffer to avoid confusing TC_EOL_IN_INSN.  */
 371           *limit = '\0';
 372
 373           /* Find last newline.  */
 374           for (p = limit - 1; *p != '\n' || TC_EOL_IN_INSN (p); --p)
 375             if (p < start)
 376               goto read_more;
 377           ++p;
 378         }
 379
 380       /* We found a newline in the newly read chars.  */
 381       partial_where = p;
 382       partial_size = limit - p;
 383
 384       /* Save the fragment after that last newline.  */
 385       memcpy (save_source, partial_where, (int) AFTER_SIZE);
 386       memcpy (partial_where, AFTER_STRING, (int) AFTER_SIZE);
 387       return partial_where;
 388
 389     read_more:
 390       /* Didn't find a newline.  Read more text.  */
 391       partial_size = limit - (buffer_start + BEFORE_SIZE);
 392       if (buffer_length - input_file_buffer_size () < partial_size)
 393         {
 394           /* Increase the buffer when it doesn't have room for the
 395              next block of input.  */
 396           buffer_length *= 2;
 397           buffer_start = XRESIZEVEC (char, buffer_start,
 398                                      (buffer_length
 399                                       + BEFORE_SIZE + AFTER_SIZE + 1));
 400         }
 401     }
 402
 403   /* Tell the listing we've finished the file.  */
 404   LISTING_EOF ();
 405
 406   /* If we should pop to another file at EOF, do it.  */
 407   partial_where = NULL;
 408   if (next_saved_file)
 409     *bufp = input_scrub_pop (next_saved_file);
 410
 411   return partial_where;
 412 }
 413 \f
 414 /* The remaining part of this file deals with line numbers, error
 415    messages and so on.  Return TRUE if we opened any file.  */
 416
 417 int
 418 seen_at_least_1_file (void)
 419 {
 420   return (physical_input_file != NULL);
 421 }
 422
 423 void
 424 bump_line_counters (void)
 425 {
 426   if (sb_index == (size_t) -1)
 427     {
 428       ++physical_input_line;
 429       if (logical_input_line >= 0)
 430         ++logical_input_line;
 431     }
 432 }
 433 \f
 434 /* Tells us what the new logical line number and file are.
 435    If the line_number is -1, we don't change the current logical line
 436    number.  If it is -2, we decrement the logical line number (this is
 437    to support the .appfile pseudo-op inserted into the stream by
 438    do_scrub_chars).
 439    If the fname is NULL, we don't change the current logical file name.
 440    Returns nonzero if the filename actually changes.  */
 441
 442 int
 443 new_logical_line_flags (const char *fname, /* DON'T destroy it!  We point to it!  */
 444                         int line_number,
 445                         int flags)
 446 {
 447   switch (flags)
 448     {
 449     case 0:
 450       break;
 451     case 1:
 452       if (line_number != -1)
 453         abort ();
 454       break;
 455     case 1 << 1:
 456     case 1 << 2:
 457       /* FIXME: we could check that include nesting is correct.  */
 458       break;
 459     default:
 460       abort ();
 461     }
 462
 463   if (line_number >= 0)
 464     logical_input_line = line_number;
 465   else if (line_number == -1 && fname && !*fname && (flags & (1 << 2)))
 466     {
 467       logical_input_file = physical_input_file;
 468       logical_input_line = physical_input_line;
 469       fname = NULL;
 470     }
 471
 472   if (fname
 473       && (logical_input_file == NULL
 474           || filename_cmp (logical_input_file, fname)))
 475     {
 476       logical_input_file = fname;
 477       return 1;
 478     }
 479   else
 480     return 0;
 481 }
 482
 483 int
 484 new_logical_line (const char *fname, int line_number)
 485 {
 486   return new_logical_line_flags (fname, line_number, 0);
 487 }
 488
 489 \f
 490 /* Return the current physical input file name and line number, if known  */
 491
 492 const char *
 493 as_where_physical (unsigned int *linep)
 494 {
 495   if (physical_input_file != NULL)
 496     {
 497       if (linep != NULL)
 498         *linep = physical_input_line;
 499       return physical_input_file;
 500     }
 501
 502   if (linep != NULL)
 503     *linep = 0;
 504   return NULL;
 505 }
 506
 507 /* Return the current file name and line number.  */
 508
 509 const char *
 510 as_where (unsigned int *linep)
 511 {
 512   if (logical_input_file != NULL
 513       && (linep == NULL || logical_input_line >= 0))
 514     {
 515       if (linep != NULL)
 516         *linep = logical_input_line;
 517       return logical_input_file;
 518     }
 519
 520   return as_where_physical (linep);
 521 }
 522