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1 /* input_scrub.c - Break up input buffers into whole numbers of lines.
2    Copyright (C) 1987-2014 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 
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 int 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 /* What is the largest size buffer that input_file_give_next_buffer()
72    could return to us?  */
73 static unsigned int buffer_length;
74 
75 /* The index into an sb structure we are reading from.  -1 if none.  */
76 static size_t sb_index = -1;
77 
78 /* If we are reading from an sb structure, this is it.  */
79 static sb from_sb;
80 
81 /* Should we do a conditional check on from_sb? */
82 static int from_sb_is_expansion = 1;
83 
84 /* The number of nested sb structures we have included.  */
85 int macro_nest;
86 
87 /* We can have more than one source file open at once, though the info for all
88    but the latest one are saved off in a struct input_save.  These files remain
89    open, so we are limited by the number of open files allowed by the
90    underlying OS. We may also sequentially read more than one source file in an
91    assembly.  */
92 
93 /* We must track the physical file and line number for error messages. We also
94    track a "logical" file and line number corresponding to (C?)  compiler
95    source line numbers.  Whenever we open a file we must fill in
96    physical_input_file. So if it is NULL we have not opened any files yet.  */
97 
98 static char *physical_input_file;
99 static char *logical_input_file;
100 
101 /* 1-origin line number in a source file.  */
102 /* A line ends in '\n' or eof.  */
103 static unsigned int physical_input_line;
104 static int logical_input_line;
105 
106 /* Struct used to save the state of the input handler during include files */
107 struct input_save {
108   char *              buffer_start;
109   char *              partial_where;
110   int                 partial_size;
111   char                save_source[AFTER_SIZE];
112   size_t              buffer_length;
113   char *              physical_input_file;
114   char *              logical_input_file;
115   unsigned int        physical_input_line;
116   int                 logical_input_line;
117   size_t              sb_index;
118   sb                  from_sb;
119   int                 from_sb_is_expansion; /* Should we do a conditional check?  */
120   struct input_save * next_saved_file;	/* Chain of input_saves.  */
121   char *              input_file_save;	/* Saved state of input routines.  */
122   char *              saved_position;	/* Caller's saved position in buf.  */
123 };
124 
125 static struct input_save *input_scrub_push (char *saved_position);
126 static char *input_scrub_pop (struct input_save *arg);
127 
128 /* Saved information about the file that .include'd this one.  When we hit EOF,
129    we automatically pop to that file.  */
130 
131 static struct input_save *next_saved_file;
132 
133 /* Push the state of input reading and scrubbing so that we can #include.
134    The return value is a 'void *' (fudged for old compilers) to a save
135    area, which can be restored by passing it to input_scrub_pop().  */
136 
137 static struct input_save *
input_scrub_push(char * saved_position)138 input_scrub_push (char *saved_position)
139 {
140   struct input_save *saved;
141 
142   saved = (struct input_save *) xmalloc (sizeof *saved);
143 
144   saved->saved_position = saved_position;
145   saved->buffer_start = buffer_start;
146   saved->partial_where = partial_where;
147   saved->partial_size = partial_size;
148   saved->buffer_length = buffer_length;
149   saved->physical_input_file = physical_input_file;
150   saved->logical_input_file = logical_input_file;
151   saved->physical_input_line = physical_input_line;
152   saved->logical_input_line = logical_input_line;
153   saved->sb_index = sb_index;
154   saved->from_sb = from_sb;
155   saved->from_sb_is_expansion = from_sb_is_expansion;
156   memcpy (saved->save_source, save_source, sizeof (save_source));
157   saved->next_saved_file = next_saved_file;
158   saved->input_file_save = input_file_push ();
159 
160   input_file_begin ();		/* Reinitialize! */
161   logical_input_line = -1;
162   logical_input_file = (char *) NULL;
163   buffer_length = input_file_buffer_size ();
164   sb_index = -1;
165 
166   buffer_start = (char *) xmalloc ((BEFORE_SIZE + buffer_length
167                                     + buffer_length + AFTER_SIZE));
168   memcpy (buffer_start, BEFORE_STRING, (int) BEFORE_SIZE);
169 
170   return saved;
171 }
172 
173 static char *
input_scrub_pop(struct input_save * saved)174 input_scrub_pop (struct input_save *saved)
175 {
176   char *saved_position;
177 
178   input_scrub_end ();		/* Finish off old buffer */
179 
180   input_file_pop (saved->input_file_save);
181   saved_position = saved->saved_position;
182   buffer_start = saved->buffer_start;
183   buffer_length = saved->buffer_length;
184   physical_input_file = saved->physical_input_file;
185   logical_input_file = saved->logical_input_file;
186   physical_input_line = saved->physical_input_line;
187   logical_input_line = saved->logical_input_line;
188   sb_index = saved->sb_index;
189   from_sb = saved->from_sb;
190   from_sb_is_expansion = saved->from_sb_is_expansion;
191   partial_where = saved->partial_where;
192   partial_size = saved->partial_size;
193   next_saved_file = saved->next_saved_file;
194   memcpy (save_source, saved->save_source, sizeof (save_source));
195 
196   free (saved);
197   return saved_position;
198 }
199 
200 void
input_scrub_begin(void)201 input_scrub_begin (void)
202 {
203   know (strlen (BEFORE_STRING) == BEFORE_SIZE);
204   know (strlen (AFTER_STRING) == AFTER_SIZE
205 	|| (AFTER_STRING[0] == '\0' && AFTER_SIZE == 1));
206 
207   input_file_begin ();
208 
209   buffer_length = input_file_buffer_size ();
210 
211   buffer_start = (char *) xmalloc ((BEFORE_SIZE + buffer_length
212                                     + buffer_length + AFTER_SIZE));
213   memcpy (buffer_start, BEFORE_STRING, (int) BEFORE_SIZE);
214 
215   /* Line number things.  */
216   logical_input_line = -1;
217   logical_input_file = (char *) NULL;
218   physical_input_file = NULL;	/* No file read yet.  */
219   next_saved_file = NULL;	/* At EOF, don't pop to any other file */
220   do_scrub_begin (flag_m68k_mri);
221 }
222 
223 void
input_scrub_end(void)224 input_scrub_end (void)
225 {
226   if (buffer_start)
227     {
228       free (buffer_start);
229       buffer_start = 0;
230       input_file_end ();
231     }
232 }
233 
234 /* Start reading input from a new file.
235    Return start of caller's part of buffer.  */
236 
237 char *
input_scrub_new_file(char * filename)238 input_scrub_new_file (char *filename)
239 {
240   input_file_open (filename, !flag_no_comments);
241   physical_input_file = filename[0] ? filename : _("{standard input}");
242   physical_input_line = 0;
243 
244   partial_size = 0;
245   return (buffer_start + BEFORE_SIZE);
246 }
247 
248 /* Include a file from the current file.  Save our state, cause it to
249    be restored on EOF, and begin handling a new file.  Same result as
250    input_scrub_new_file.  */
251 
252 char *
input_scrub_include_file(char * filename,char * position)253 input_scrub_include_file (char *filename, char *position)
254 {
255   next_saved_file = input_scrub_push (position);
256   return input_scrub_new_file (filename);
257 }
258 
259 /* Start getting input from an sb structure.  This is used when
260    expanding a macro.  */
261 
262 void
input_scrub_include_sb(sb * from,char * position,int is_expansion)263 input_scrub_include_sb (sb *from, char *position, int is_expansion)
264 {
265   int newline;
266 
267   if (macro_nest > max_macro_nest)
268     as_fatal (_("macros nested too deeply"));
269   ++macro_nest;
270 
271 #ifdef md_macro_start
272   if (is_expansion)
273     {
274       md_macro_start ();
275     }
276 #endif
277 
278   next_saved_file = input_scrub_push (position);
279 
280   /* Allocate sufficient space: from->len + optional newline.  */
281   newline = from->len >= 1 && from->ptr[0] != '\n';
282   sb_build (&from_sb, from->len + newline);
283   from_sb_is_expansion = is_expansion;
284   if (newline)
285     {
286       /* Add the sentinel required by read.c.  */
287       sb_add_char (&from_sb, '\n');
288     }
289   sb_scrub_and_add_sb (&from_sb, from);
290 
291   /* Make sure the parser looks at defined contents when it scans for
292      e.g. end-of-line at the end of a macro.  */
293   sb_terminate (&from_sb);
294 
295   sb_index = 1;
296 
297   /* These variables are reset by input_scrub_push.  Restore them
298      since we are, after all, still at the same point in the file.  */
299   logical_input_line = next_saved_file->logical_input_line;
300   logical_input_file = next_saved_file->logical_input_file;
301 }
302 
303 void
input_scrub_close(void)304 input_scrub_close (void)
305 {
306   input_file_close ();
307   physical_input_line = 0;
308   logical_input_line = -1;
309 }
310 
311 char *
input_scrub_next_buffer(char ** bufp)312 input_scrub_next_buffer (char **bufp)
313 {
314   char *limit;		/*->just after last char of buffer.  */
315 
316   if (sb_index != (size_t) -1)
317     {
318       if (sb_index >= from_sb.len)
319 	{
320 	  sb_kill (&from_sb);
321 	  if (from_sb_is_expansion)
322 	    {
323 	      cond_finish_check (macro_nest);
324 #ifdef md_macro_end
325 	      /* Allow the target to clean up per-macro expansion
326 	         data.  */
327 	      md_macro_end ();
328 #endif
329 	    }
330 	  --macro_nest;
331 	  partial_where = NULL;
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   *bufp = buffer_start + BEFORE_SIZE;
345 
346   if (partial_size)
347     {
348       memmove (buffer_start + BEFORE_SIZE, partial_where,
349 	       (unsigned int) partial_size);
350       memcpy (buffer_start + BEFORE_SIZE, save_source, AFTER_SIZE);
351     }
352   limit = input_file_give_next_buffer (buffer_start
353 				       + BEFORE_SIZE
354 				       + partial_size);
355   if (limit)
356     {
357       char *p;		/* Find last newline.  */
358       /* Terminate the buffer to avoid confusing TC_EOL_IN_INSN.  */
359       *limit = '\0';
360       for (p = limit - 1; *p != '\n' || TC_EOL_IN_INSN (p); --p)
361 	;
362       ++p;
363 
364       while (p <= buffer_start + BEFORE_SIZE)
365 	{
366 	  int limoff;
367 
368 	  limoff = limit - buffer_start;
369 	  buffer_length += input_file_buffer_size ();
370 	  buffer_start = (char *) xrealloc (buffer_start,
371                                             (BEFORE_SIZE
372                                              + 2 * buffer_length
373                                              + AFTER_SIZE));
374 	  *bufp = buffer_start + BEFORE_SIZE;
375 	  limit = input_file_give_next_buffer (buffer_start + limoff);
376 
377 	  if (limit == NULL)
378 	    {
379 	      as_warn (_("partial line at end of file ignored"));
380 	      partial_where = NULL;
381 	      if (next_saved_file)
382 		*bufp = input_scrub_pop (next_saved_file);
383 	      return NULL;
384 	    }
385 
386 	  /* Terminate the buffer to avoid confusing TC_EOL_IN_INSN.  */
387 	  *limit = '\0';
388 	  for (p = limit - 1; *p != '\n' || TC_EOL_IN_INSN (p); --p)
389 	    ;
390 	  ++p;
391 	}
392 
393       partial_where = p;
394       partial_size = limit - p;
395       memcpy (save_source, partial_where, (int) AFTER_SIZE);
396       memcpy (partial_where, AFTER_STRING, (int) AFTER_SIZE);
397     }
398   else
399     {
400       partial_where = 0;
401       if (partial_size > 0)
402 	{
403 	  as_warn (_("partial line at end of file ignored"));
404 	}
405 
406       /* Tell the listing we've finished the file.  */
407       LISTING_EOF ();
408 
409       /* If we should pop to another file at EOF, do it.  */
410       if (next_saved_file)
411 	{
412 	  *bufp = input_scrub_pop (next_saved_file);	/* Pop state */
413 	  /* partial_where is now correct to return, since we popped it.  */
414 	}
415     }
416   return (partial_where);
417 }
418 
419 /* The remaining part of this file deals with line numbers, error
420    messages and so on.  Return TRUE if we opened any file.  */
421 
422 int
seen_at_least_1_file(void)423 seen_at_least_1_file (void)
424 {
425   return (physical_input_file != NULL);
426 }
427 
428 void
bump_line_counters(void)429 bump_line_counters (void)
430 {
431   if (sb_index == (size_t) -1)
432     {
433       ++physical_input_line;
434       if (logical_input_line >= 0)
435 	++logical_input_line;
436     }
437 }
438 
439 /* Tells us what the new logical line number and file are.
440    If the line_number is -1, we don't change the current logical line
441    number.  If it is -2, we decrement the logical line number (this is
442    to support the .appfile pseudo-op inserted into the stream by
443    do_scrub_chars).
444    If the fname is NULL, we don't change the current logical file name.
445    Returns nonzero if the filename actually changes.  */
446 
447 int
new_logical_line_flags(char * fname,int line_number,int flags)448 new_logical_line_flags (char *fname, /* DON'T destroy it!  We point to it!  */
449 			int line_number,
450 			int flags)
451 {
452   switch (flags)
453     {
454     case 0:
455       break;
456     case 1:
457       if (line_number != -1)
458 	abort ();
459       break;
460     case 1 << 1:
461     case 1 << 2:
462       /* FIXME: we could check that include nesting is correct.  */
463       break;
464     default:
465       abort ();
466     }
467 
468   if (line_number >= 0)
469     logical_input_line = line_number;
470   else if (line_number == -1 && fname && !*fname && (flags & (1 << 2)))
471     {
472       logical_input_file = physical_input_file;
473       logical_input_line = physical_input_line;
474       fname = NULL;
475     }
476 
477   if (fname
478       && (logical_input_file == NULL
479 	  || filename_cmp (logical_input_file, fname)))
480     {
481       logical_input_file = fname;
482       return 1;
483     }
484   else
485     return 0;
486 }
487 
488 int
new_logical_line(char * fname,int line_number)489 new_logical_line (char *fname, int line_number)
490 {
491   return new_logical_line_flags (fname, line_number, 0);
492 }
493 
494 
495 /* Return the current file name and line number.
496    namep should be char * const *, but there are compilers which screw
497    up declarations like that, and it's easier to avoid it.  */
498 
499 void
as_where(char ** namep,unsigned int * linep)500 as_where (char **namep, unsigned int *linep)
501 {
502   if (logical_input_file != NULL
503       && (linep == NULL || logical_input_line >= 0))
504     {
505       *namep = logical_input_file;
506       if (linep != NULL)
507 	*linep = logical_input_line;
508     }
509   else if (physical_input_file != NULL)
510     {
511       *namep = physical_input_file;
512       if (linep != NULL)
513 	*linep = physical_input_line;
514     }
515   else
516     {
517       *namep = 0;
518       if (linep != NULL)
519 	*linep = 0;
520     }
521 }
522