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[binutils.git] / gas / stabs.c
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1 /* Generic stabs parsing for gas.
2 Copyright 1989, 1990, 1991, 1993, 1995, 1996, 1997, 1998, 2000, 2001
3 2002, 2003, 2004, 2005, 2007, 2009 Free Software Foundation, Inc.
5 This file is part of GAS, the GNU Assembler.
7 GAS is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as
9 published by the Free Software Foundation; either version 3,
10 or (at your option) any later version.
12 GAS is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 the GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GAS; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
20 02110-1301, USA. */
22 #include "as.h"
23 #include "filenames.h"
24 #include "obstack.h"
25 #include "subsegs.h"
26 #include "ecoff.h"
28 /* We need this, despite the apparent object format dependency, since
29 it defines stab types, which all object formats can use now. */
31 #include "aout/stab_gnu.h"
33 /* Holds whether the assembler is generating stabs line debugging
34 information or not. Potentially used by md_cleanup function. */
36 int outputting_stabs_line_debug = 0;
38 static void s_stab_generic (int, char *, char *);
39 static void generate_asm_file (int, char *);
41 /* Allow backends to override the names used for the stab sections. */
42 #ifndef STAB_SECTION_NAME
43 #define STAB_SECTION_NAME ".stab"
44 #endif
46 #ifndef STAB_STRING_SECTION_NAME
47 #define STAB_STRING_SECTION_NAME ".stabstr"
48 #endif
50 /* Non-zero if we're in the middle of a .func function, in which case
51 stabs_generate_asm_lineno emits function relative line number stabs.
52 Otherwise it emits line number stabs with absolute addresses. Note that
53 both cases only apply to assembler code assembled with -gstabs. */
54 static int in_dot_func_p;
56 /* Label at start of current function if in_dot_func_p != 0. */
57 static const char *current_function_label;
60 * Handle .stabX directives, which used to be open-coded.
61 * So much creeping featurism overloaded the semantics that we decided
62 * to put all .stabX thinking in one place. Here.
64 * We try to make any .stabX directive legal. Other people's AS will often
65 * do assembly-time consistency checks: eg assigning meaning to n_type bits
66 * and "protecting" you from setting them to certain values. (They also zero
67 * certain bits before emitting symbols. Tut tut.)
69 * If an expression is not absolute we either gripe or use the relocation
70 * information. Other people's assemblers silently forget information they
71 * don't need and invent information they need that you didn't supply.
75 * Build a string dictionary entry for a .stabX symbol.
76 * The symbol is added to the .<secname>str section.
79 #ifndef SEPARATE_STAB_SECTIONS
80 #define SEPARATE_STAB_SECTIONS 0
81 #endif
83 unsigned int
84 get_stab_string_offset (const char *string, const char *stabstr_secname)
86 unsigned int length;
87 unsigned int retval;
88 segT save_seg;
89 subsegT save_subseg;
90 segT seg;
91 char *p;
93 if (! SEPARATE_STAB_SECTIONS)
94 abort ();
96 length = strlen (string);
98 save_seg = now_seg;
99 save_subseg = now_subseg;
101 /* Create the stab string section. */
102 seg = subseg_new (stabstr_secname, 0);
104 retval = seg_info (seg)->stabu.stab_string_size;
105 if (retval <= 0)
107 /* Make sure the first string is empty. */
108 p = frag_more (1);
109 *p = 0;
110 retval = seg_info (seg)->stabu.stab_string_size = 1;
111 bfd_set_section_flags (stdoutput, seg, SEC_READONLY | SEC_DEBUGGING);
112 if (seg->name == stabstr_secname)
113 seg->name = xstrdup (stabstr_secname);
116 if (length > 0)
117 { /* Ordinary case. */
118 p = frag_more (length + 1);
119 strcpy (p, string);
121 seg_info (seg)->stabu.stab_string_size += length + 1;
123 else
124 retval = 0;
126 subseg_set (save_seg, save_subseg);
128 return retval;
131 #ifdef AOUT_STABS
132 #ifndef OBJ_PROCESS_STAB
133 #define OBJ_PROCESS_STAB(SEG,W,S,T,O,D) aout_process_stab(W,S,T,O,D)
134 #endif
136 /* Here instead of obj-aout.c because other formats use it too. */
137 void
138 aout_process_stab (what, string, type, other, desc)
139 int what;
140 const char *string;
141 int type, other, desc;
143 /* Put the stab information in the symbol table. */
144 symbolS *symbol;
146 /* Create the symbol now, but only insert it into the symbol chain
147 after any symbols mentioned in the value expression get into the
148 symbol chain. This is to avoid "continuation symbols" (where one
149 ends in "\" and the debug info is continued in the next .stabs
150 directive) from being separated by other random symbols. */
151 symbol = symbol_create (string, undefined_section, 0,
152 &zero_address_frag);
153 if (what == 's' || what == 'n')
155 /* Pick up the value from the input line. */
156 pseudo_set (symbol);
158 else
160 /* .stabd sets the name to NULL. Why? */
161 S_SET_NAME (symbol, NULL);
162 symbol_set_frag (symbol, frag_now);
163 S_SET_VALUE (symbol, (valueT) frag_now_fix ());
166 symbol_append (symbol, symbol_lastP, &symbol_rootP, &symbol_lastP);
168 symbol_get_bfdsym (symbol)->flags |= BSF_DEBUGGING;
170 S_SET_TYPE (symbol, type);
171 S_SET_OTHER (symbol, other);
172 S_SET_DESC (symbol, desc);
174 #endif
176 /* This can handle different kinds of stabs (s,n,d) and different
177 kinds of stab sections. */
179 static void
180 s_stab_generic (int what, char *stab_secname, char *stabstr_secname)
182 long longint;
183 char *string, *saved_string_obstack_end;
184 int type;
185 int other;
186 int desc;
188 /* The general format is:
189 .stabs "STRING",TYPE,OTHER,DESC,VALUE
190 .stabn TYPE,OTHER,DESC,VALUE
191 .stabd TYPE,OTHER,DESC
192 At this point input_line_pointer points after the pseudo-op and
193 any trailing whitespace. The argument what is one of 's', 'n' or
194 'd' indicating which type of .stab this is. */
196 if (what != 's')
198 string = "";
199 saved_string_obstack_end = 0;
201 else
203 int length;
205 string = demand_copy_C_string (&length);
206 /* FIXME: We should probably find some other temporary storage
207 for string, rather than leaking memory if someone else
208 happens to use the notes obstack. */
209 saved_string_obstack_end = notes.next_free;
210 SKIP_WHITESPACE ();
211 if (*input_line_pointer == ',')
212 input_line_pointer++;
213 else
215 as_warn (_(".stab%c: missing comma"), what);
216 ignore_rest_of_line ();
217 return;
221 if (get_absolute_expression_and_terminator (&longint) != ',')
223 as_warn (_(".stab%c: missing comma"), what);
224 ignore_rest_of_line ();
225 return;
227 type = longint;
229 if (get_absolute_expression_and_terminator (&longint) != ',')
231 as_warn (_(".stab%c: missing comma"), what);
232 ignore_rest_of_line ();
233 return;
235 other = longint;
237 desc = get_absolute_expression ();
239 if ((desc > 0xffff) || (desc < -0x8000))
240 /* This could happen for example with a source file with a huge
241 number of lines. The only cure is to use a different debug
242 format, probably DWARF. */
243 as_warn (_(".stab%c: description field '%x' too big, try a different debug format"),
244 what, desc);
246 if (what == 's' || what == 'n')
248 if (*input_line_pointer != ',')
250 as_warn (_(".stab%c: missing comma"), what);
251 ignore_rest_of_line ();
252 return;
254 input_line_pointer++;
255 SKIP_WHITESPACE ();
258 #ifdef TC_PPC
259 #ifdef OBJ_ELF
260 /* Solaris on PowerPC has decided that .stabd can take 4 arguments, so if we were
261 given 4 arguments, make it a .stabn */
262 else if (what == 'd')
264 char *save_location = input_line_pointer;
266 SKIP_WHITESPACE ();
267 if (*input_line_pointer == ',')
269 input_line_pointer++;
270 what = 'n';
272 else
273 input_line_pointer = save_location;
275 #endif /* OBJ_ELF */
276 #endif /* TC_PPC */
278 #ifndef NO_LISTING
279 if (listing)
281 switch (type)
283 case N_SLINE:
284 listing_source_line ((unsigned int) desc);
285 break;
286 case N_SO:
287 case N_SOL:
288 listing_source_file (string);
289 break;
292 #endif /* ! NO_LISTING */
294 /* We have now gathered the type, other, and desc information. For
295 .stabs or .stabn, input_line_pointer is now pointing at the
296 value. */
298 if (SEPARATE_STAB_SECTIONS)
299 /* Output the stab information in a separate section. This is used
300 at least for COFF and ELF. */
302 segT saved_seg = now_seg;
303 subsegT saved_subseg = now_subseg;
304 fragS *saved_frag = frag_now;
305 valueT dot;
306 segT seg;
307 unsigned int stroff;
308 char *p;
310 static segT cached_sec;
311 static char *cached_secname;
313 dot = frag_now_fix ();
315 #ifdef md_flush_pending_output
316 md_flush_pending_output ();
317 #endif
319 if (cached_secname && !strcmp (cached_secname, stab_secname))
321 seg = cached_sec;
322 subseg_set (seg, 0);
324 else
326 seg = subseg_new (stab_secname, 0);
327 if (cached_secname)
328 free (cached_secname);
329 cached_secname = xstrdup (stab_secname);
330 cached_sec = seg;
333 if (! seg_info (seg)->hadone)
335 bfd_set_section_flags (stdoutput, seg,
336 SEC_READONLY | SEC_RELOC | SEC_DEBUGGING);
337 #ifdef INIT_STAB_SECTION
338 INIT_STAB_SECTION (seg);
339 #endif
340 seg_info (seg)->hadone = 1;
343 stroff = get_stab_string_offset (string, stabstr_secname);
344 if (what == 's')
346 /* Release the string, if nobody else has used the obstack. */
347 if (saved_string_obstack_end == notes.next_free)
348 obstack_free (&notes, string);
351 /* At least for now, stabs in a special stab section are always
352 output as 12 byte blocks of information. */
353 p = frag_more (8);
354 md_number_to_chars (p, (valueT) stroff, 4);
355 md_number_to_chars (p + 4, (valueT) type, 1);
356 md_number_to_chars (p + 5, (valueT) other, 1);
357 md_number_to_chars (p + 6, (valueT) desc, 2);
359 if (what == 's' || what == 'n')
361 /* Pick up the value from the input line. */
362 cons (4);
363 input_line_pointer--;
365 else
367 symbolS *symbol;
368 expressionS exp;
370 /* Arrange for a value representing the current location. */
371 symbol = symbol_temp_new (saved_seg, dot, saved_frag);
373 exp.X_op = O_symbol;
374 exp.X_add_symbol = symbol;
375 exp.X_add_number = 0;
377 emit_expr (&exp, 4);
380 #ifdef OBJ_PROCESS_STAB
381 OBJ_PROCESS_STAB (seg, what, string, type, other, desc);
382 #endif
384 subseg_set (saved_seg, saved_subseg);
386 else
388 #ifdef OBJ_PROCESS_STAB
389 OBJ_PROCESS_STAB (0, what, string, type, other, desc);
390 #else
391 abort ();
392 #endif
395 demand_empty_rest_of_line ();
398 /* Regular stab directive. */
400 void
401 s_stab (int what)
403 s_stab_generic (what, STAB_SECTION_NAME, STAB_STRING_SECTION_NAME);
406 /* "Extended stabs", used in Solaris only now. */
408 void
409 s_xstab (int what)
411 int length;
412 char *stab_secname, *stabstr_secname;
413 static char *saved_secname, *saved_strsecname;
415 /* @@ MEMORY LEAK: This allocates a copy of the string, but in most
416 cases it will be the same string, so we could release the storage
417 back to the obstack it came from. */
418 stab_secname = demand_copy_C_string (&length);
419 SKIP_WHITESPACE ();
420 if (*input_line_pointer == ',')
421 input_line_pointer++;
422 else
424 as_bad (_("comma missing in .xstabs"));
425 ignore_rest_of_line ();
426 return;
429 /* To get the name of the stab string section, simply add "str" to
430 the stab section name. */
431 if (saved_secname == 0 || strcmp (saved_secname, stab_secname))
433 stabstr_secname = (char *) xmalloc (strlen (stab_secname) + 4);
434 strcpy (stabstr_secname, stab_secname);
435 strcat (stabstr_secname, "str");
436 if (saved_secname)
438 free (saved_secname);
439 free (saved_strsecname);
441 saved_secname = stab_secname;
442 saved_strsecname = stabstr_secname;
444 s_stab_generic (what, saved_secname, saved_strsecname);
447 #ifdef S_SET_DESC
449 /* Frob invented at RMS' request. Set the n_desc of a symbol. */
451 void
452 s_desc (ignore)
453 int ignore ATTRIBUTE_UNUSED;
455 char *name;
456 char c;
457 char *p;
458 symbolS *symbolP;
459 int temp;
461 name = input_line_pointer;
462 c = get_symbol_end ();
463 p = input_line_pointer;
464 *p = c;
465 SKIP_WHITESPACE ();
466 if (*input_line_pointer != ',')
468 *p = 0;
469 as_bad (_("expected comma after \"%s\""), name);
470 *p = c;
471 ignore_rest_of_line ();
473 else
475 input_line_pointer++;
476 temp = get_absolute_expression ();
477 *p = 0;
478 symbolP = symbol_find_or_make (name);
479 *p = c;
480 S_SET_DESC (symbolP, temp);
482 demand_empty_rest_of_line ();
483 } /* s_desc() */
485 #endif /* defined (S_SET_DESC) */
487 /* Generate stabs debugging information to denote the main source file. */
489 void
490 stabs_generate_asm_file (void)
492 char *file;
493 unsigned int lineno;
495 as_where (&file, &lineno);
496 if (use_gnu_debug_info_extensions)
498 const char *dir;
499 char *dir2;
501 dir = remap_debug_filename (getpwd ());
502 dir2 = (char *) alloca (strlen (dir) + 2);
503 sprintf (dir2, "%s%s", dir, "/");
504 generate_asm_file (N_SO, dir2);
505 xfree ((char *) dir);
507 generate_asm_file (N_SO, file);
510 /* Generate stabs debugging information to denote the source file.
511 TYPE is one of N_SO, N_SOL. */
513 static void
514 generate_asm_file (int type, char *file)
516 static char *last_file;
517 static int label_count;
518 char *hold;
519 char sym[30];
520 char *buf;
521 char *tmp = file;
522 char *file_endp = file + strlen (file);
523 char *bufp;
525 if (last_file != NULL
526 && filename_cmp (last_file, file) == 0)
527 return;
529 /* Rather than try to do this in some efficient fashion, we just
530 generate a string and then parse it again. That lets us use the
531 existing stabs hook, which expect to see a string, rather than
532 inventing new ones. */
533 hold = input_line_pointer;
535 sprintf (sym, "%sF%d", FAKE_LABEL_NAME, label_count);
536 ++label_count;
538 /* Allocate enough space for the file name (possibly extended with
539 doubled up backslashes), the symbol name, and the other characters
540 that make up a stabs file directive. */
541 bufp = buf = (char *) xmalloc (2 * strlen (file) + strlen (sym) + 12);
543 *bufp++ = '"';
545 while (tmp < file_endp)
547 char *bslash = strchr (tmp, '\\');
548 size_t len = (bslash) ? (size_t) (bslash - tmp + 1) : strlen (tmp);
550 /* Double all backslashes, since demand_copy_C_string (used by
551 s_stab to extract the part in quotes) will try to replace them as
552 escape sequences. backslash may appear in a filespec. */
553 strncpy (bufp, tmp, len);
555 tmp += len;
556 bufp += len;
558 if (bslash != NULL)
559 *bufp++ = '\\';
562 sprintf (bufp, "\",%d,0,0,%s\n", type, sym);
564 input_line_pointer = buf;
565 s_stab ('s');
566 colon (sym);
568 if (last_file != NULL)
569 free (last_file);
570 last_file = xstrdup (file);
572 free (buf);
574 input_line_pointer = hold;
577 /* Generate stabs debugging information for the current line. This is
578 used to produce debugging information for an assembler file. */
580 void
581 stabs_generate_asm_lineno (void)
583 static int label_count;
584 char *hold;
585 char *file;
586 unsigned int lineno;
587 char *buf;
588 char sym[30];
589 /* Remember the last file/line and avoid duplicates. */
590 static unsigned int prev_lineno = -1;
591 static char *prev_file = NULL;
593 /* Rather than try to do this in some efficient fashion, we just
594 generate a string and then parse it again. That lets us use the
595 existing stabs hook, which expect to see a string, rather than
596 inventing new ones. */
598 hold = input_line_pointer;
600 as_where (&file, &lineno);
602 /* Don't emit sequences of stabs for the same line. */
603 if (prev_file == NULL)
605 /* First time thru. */
606 prev_file = xstrdup (file);
607 prev_lineno = lineno;
609 else if (lineno == prev_lineno
610 && filename_cmp (file, prev_file) == 0)
612 /* Same file/line as last time. */
613 return;
615 else
617 /* Remember file/line for next time. */
618 prev_lineno = lineno;
619 if (filename_cmp (file, prev_file) != 0)
621 free (prev_file);
622 prev_file = xstrdup (file);
626 /* Let the world know that we are in the middle of generating a
627 piece of stabs line debugging information. */
628 outputting_stabs_line_debug = 1;
630 generate_asm_file (N_SOL, file);
632 sprintf (sym, "%sL%d", FAKE_LABEL_NAME, label_count);
633 ++label_count;
635 if (in_dot_func_p)
637 buf = (char *) alloca (100 + strlen (current_function_label));
638 sprintf (buf, "%d,0,%d,%s-%s\n", N_SLINE, lineno,
639 sym, current_function_label);
641 else
643 buf = (char *) alloca (100);
644 sprintf (buf, "%d,0,%d,%s\n", N_SLINE, lineno, sym);
646 input_line_pointer = buf;
647 s_stab ('n');
648 colon (sym);
650 input_line_pointer = hold;
651 outputting_stabs_line_debug = 0;
654 /* Emit a function stab.
655 All assembler functions are assumed to have return type `void'. */
657 void
658 stabs_generate_asm_func (const char *funcname, const char *startlabname)
660 static int void_emitted_p;
661 char *hold = input_line_pointer;
662 char *buf;
663 char *file;
664 unsigned int lineno;
666 if (! void_emitted_p)
668 input_line_pointer = "\"void:t1=1\",128,0,0,0";
669 s_stab ('s');
670 void_emitted_p = 1;
673 as_where (&file, &lineno);
674 if (asprintf (&buf, "\"%s:F1\",%d,0,%d,%s",
675 funcname, N_FUN, lineno + 1, startlabname) == -1)
676 as_fatal ("%s", xstrerror (errno));
677 input_line_pointer = buf;
678 s_stab ('s');
679 free (buf);
681 input_line_pointer = hold;
682 current_function_label = xstrdup (startlabname);
683 in_dot_func_p = 1;
686 /* Emit a stab to record the end of a function. */
688 void
689 stabs_generate_asm_endfunc (const char *funcname ATTRIBUTE_UNUSED,
690 const char *startlabname)
692 static int label_count;
693 char *hold = input_line_pointer;
694 char *buf;
695 char sym[30];
697 sprintf (sym, "%sendfunc%d", FAKE_LABEL_NAME, label_count);
698 ++label_count;
699 colon (sym);
701 if (asprintf (&buf, "\"\",%d,0,0,%s-%s", N_FUN, sym, startlabname) == -1)
702 as_fatal ("%s", xstrerror (errno));
703 input_line_pointer = buf;
704 s_stab ('s');
705 free (buf);
707 input_line_pointer = hold;
708 in_dot_func_p = 0;
709 current_function_label = NULL;