1/* a.out object file format
2   Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1999, 2000,
3   2001, 2002, 2003, 2004, 2005, 2007, 2009, 2010
4   Free Software Foundation, Inc.
5
6   This file is part of GAS, the GNU Assembler.
7
8   GAS is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as
10   published by the Free Software Foundation; either version 3,
11   or (at your option) any later version.
12
13   GAS is distributed in the hope that it will be useful, but
14   WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
16   the GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with GAS; see the file COPYING.  If not, write to the Free
20   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
21   02110-1301, USA.  */
22
23#define OBJ_HEADER "obj-aout.h"
24
25#include "as.h"
26#undef NO_RELOC
27#include "aout/aout64.h"
28#include "obstack.h"
29
30void
31obj_aout_frob_symbol (symbolS *sym, int *punt ATTRIBUTE_UNUSED)
32{
33  flagword flags;
34  asection *sec;
35  int type;
36
37  flags = symbol_get_bfdsym (sym)->flags;
38  type = aout_symbol (symbol_get_bfdsym (sym))->type;
39  sec = S_GET_SEGMENT (sym);
40
41  /* Only frob simple symbols this way right now.  */
42  if (! (type & ~ (N_TYPE | N_EXT)))
43    {
44      if (type == (N_UNDF | N_EXT)
45	  && sec == &bfd_abs_section)
46	{
47	  sec = bfd_und_section_ptr;
48	  S_SET_SEGMENT (sym, sec);
49	}
50
51      if ((type & N_TYPE) != N_INDR
52	  && (type & N_TYPE) != N_SETA
53	  && (type & N_TYPE) != N_SETT
54	  && (type & N_TYPE) != N_SETD
55	  && (type & N_TYPE) != N_SETB
56	  && type != N_WARNING
57	  && (sec == &bfd_abs_section
58	      || sec == &bfd_und_section))
59	return;
60      if (flags & BSF_EXPORT)
61	type |= N_EXT;
62
63      switch (type & N_TYPE)
64	{
65	case N_SETA:
66	case N_SETT:
67	case N_SETD:
68	case N_SETB:
69	  /* Set the debugging flag for constructor symbols so that
70	     BFD leaves them alone.  */
71	  symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
72
73	  /* You can't put a common symbol in a set.  The way a set
74	     element works is that the symbol has a definition and a
75	     name, and the linker adds the definition to the set of
76	     that name.  That does not work for a common symbol,
77	     because the linker can't tell which common symbol the
78	     user means.  FIXME: Using as_bad here may be
79	     inappropriate, since the user may want to force a
80	     particular type without regard to the semantics of sets;
81	     on the other hand, we certainly don't want anybody to be
82	     mislead into thinking that their code will work.  */
83	  if (S_IS_COMMON (sym))
84	    as_bad (_("Attempt to put a common symbol into set %s"),
85		    S_GET_NAME (sym));
86	  /* Similarly, you can't put an undefined symbol in a set.  */
87	  else if (! S_IS_DEFINED (sym))
88	    as_bad (_("Attempt to put an undefined symbol into set %s"),
89		    S_GET_NAME (sym));
90
91	  break;
92	case N_INDR:
93	  /* Put indirect symbols in the indirect section.  */
94	  S_SET_SEGMENT (sym, bfd_ind_section_ptr);
95	  symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT;
96	  if (type & N_EXT)
97	    {
98	      symbol_get_bfdsym (sym)->flags |= BSF_EXPORT;
99	      symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL;
100	    }
101	  break;
102	case N_WARNING:
103	  /* Mark warning symbols.  */
104	  symbol_get_bfdsym (sym)->flags |= BSF_WARNING;
105	  break;
106	}
107    }
108  else
109    symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
110
111  aout_symbol (symbol_get_bfdsym (sym))->type = type;
112
113  /* Double check weak symbols.  */
114  if (S_IS_WEAK (sym) && S_IS_COMMON (sym))
115    as_bad (_("Symbol `%s' can not be both weak and common"),
116	    S_GET_NAME (sym));
117}
118
119void
120obj_aout_frob_file_before_fix (void)
121{
122  /* Relocation processing may require knowing the VMAs of the sections.
123     Since writing to a section will cause the BFD back end to compute the
124     VMAs, fake it out here....  */
125  bfd_byte b = 0;
126  bfd_boolean x = TRUE;
127  if (bfd_section_size (stdoutput, text_section) != 0)
128    x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0,
129				  (bfd_size_type) 1);
130  else if (bfd_section_size (stdoutput, data_section) != 0)
131    x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0,
132				  (bfd_size_type) 1);
133
134  gas_assert (x);
135}
136
137static void
138obj_aout_line (int ignore ATTRIBUTE_UNUSED)
139{
140  /* Assume delimiter is part of expression.
141     BSD4.2 as fails with delightful bug, so we
142     are not being incompatible here.  */
143  new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
144  demand_empty_rest_of_line ();
145}
146
147/* Handle .weak.  This is a GNU extension.  */
148
149static void
150obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
151{
152  char *name;
153  int c;
154  symbolS *symbolP;
155
156  do
157    {
158      name = input_line_pointer;
159      c = get_symbol_end ();
160      symbolP = symbol_find_or_make (name);
161      *input_line_pointer = c;
162      SKIP_WHITESPACE ();
163      S_SET_WEAK (symbolP);
164      if (c == ',')
165	{
166	  input_line_pointer++;
167	  SKIP_WHITESPACE ();
168	  if (*input_line_pointer == '\n')
169	    c = '\n';
170	}
171    }
172  while (c == ',');
173  demand_empty_rest_of_line ();
174}
175
176/* Handle .type.  On {Net,Open}BSD, this is used to set the n_other field,
177   which is then apparently used when doing dynamic linking.  Older
178   versions of gas ignored the .type pseudo-op, so we also ignore it if
179   we can't parse it.  */
180
181static void
182obj_aout_type (int ignore ATTRIBUTE_UNUSED)
183{
184  char *name;
185  int c;
186  symbolS *sym;
187
188  name = input_line_pointer;
189  c = get_symbol_end ();
190  sym = symbol_find_or_make (name);
191  *input_line_pointer = c;
192  SKIP_WHITESPACE ();
193  if (*input_line_pointer == ',')
194    {
195      ++input_line_pointer;
196      SKIP_WHITESPACE ();
197      if (*input_line_pointer == '@')
198	{
199	  ++input_line_pointer;
200	  if (strncmp (input_line_pointer, "object", 6) == 0)
201	    S_SET_OTHER (sym, 1);
202	  else if (strncmp (input_line_pointer, "function", 8) == 0)
203	    S_SET_OTHER (sym, 2);
204	}
205    }
206
207  /* Ignore everything else on the line.  */
208  s_ignore (0);
209}
210
211/* Support for an AOUT emulation.  */
212
213static void
214aout_pop_insert (void)
215{
216  pop_insert (aout_pseudo_table);
217}
218
219static int
220obj_aout_s_get_other (symbolS *sym)
221{
222  return aout_symbol (symbol_get_bfdsym (sym))->other;
223}
224
225static void
226obj_aout_s_set_other (symbolS *sym, int o)
227{
228  aout_symbol (symbol_get_bfdsym (sym))->other = o;
229}
230
231static int
232obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
233{
234  return obj_sec_sym_ok_for_reloc (sec);
235}
236
237static void
238obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
239		       int w,
240		       const char *s,
241		       int t,
242		       int o,
243		       int d)
244{
245  aout_process_stab (w, s, t, o, d);
246}
247
248static int
249obj_aout_s_get_desc (symbolS *sym)
250{
251  return aout_symbol (symbol_get_bfdsym (sym))->desc;
252}
253
254static void
255obj_aout_s_set_desc (symbolS *sym, int d)
256{
257  aout_symbol (symbol_get_bfdsym (sym))->desc = d;
258}
259
260static int
261obj_aout_s_get_type (symbolS *sym)
262{
263  return aout_symbol (symbol_get_bfdsym (sym))->type;
264}
265
266static void
267obj_aout_s_set_type (symbolS *sym, int t)
268{
269  aout_symbol (symbol_get_bfdsym (sym))->type = t;
270}
271
272static int
273obj_aout_separate_stab_sections (void)
274{
275  return 0;
276}
277
278/* When changed, make sure these table entries match the single-format
279   definitions in obj-aout.h.  */
280
281const struct format_ops aout_format_ops =
282{
283  bfd_target_aout_flavour,
284  1,	/* dfl_leading_underscore.  */
285  0,	/* emit_section_symbols.  */
286  0,	/* begin.  */
287  0,	/* app_file.  */
288  obj_aout_frob_symbol,
289  0,	/* frob_file.  */
290  0,	/* frob_file_before_adjust.  */
291  obj_aout_frob_file_before_fix,
292  0,	/* frob_file_after_relocs.  */
293  0,	/* s_get_size.  */
294  0,	/* s_set_size.  */
295  0,	/* s_get_align.  */
296  0,	/* s_set_align.  */
297  obj_aout_s_get_other,
298  obj_aout_s_set_other,
299  obj_aout_s_get_desc,
300  obj_aout_s_set_desc,
301  obj_aout_s_get_type,
302  obj_aout_s_set_type,
303  0,	/* copy_symbol_attributes.  */
304  0,	/* generate_asm_lineno.  */
305  obj_aout_process_stab,
306  obj_aout_separate_stab_sections,
307  0,	/* init_stab_section.  */
308  obj_aout_sec_sym_ok_for_reloc,
309  aout_pop_insert,
310  0,	/* ecoff_set_ext.  */
311  0,	/* read_begin_hook.  */
312  0,	/* symbol_new_hook.  */
313  0,	/* symbol_clone_hook.  */
314  0	/* adjust_symtab.  */
315};
316
317const pseudo_typeS aout_pseudo_table[] =
318{
319  {"line", obj_aout_line, 0},	/* Source code line number.  */
320  {"ln", obj_aout_line, 0},	/* COFF line number that we use anyway.  */
321
322  {"weak", obj_aout_weak, 0},	/* Mark symbol as weak.  */
323
324  {"type", obj_aout_type, 0},
325
326  /* coff debug pseudos (ignored) */
327  {"def", s_ignore, 0},
328  {"dim", s_ignore, 0},
329  {"endef", s_ignore, 0},
330  {"ident", s_ignore, 0},
331  {"line", s_ignore, 0},
332  {"ln", s_ignore, 0},
333  {"scl", s_ignore, 0},
334  {"size", s_ignore, 0},
335  {"tag", s_ignore, 0},
336  {"val", s_ignore, 0},
337  {"version", s_ignore, 0},
338
339  {"optim", s_ignore, 0},	/* For sun386i cc (?).  */
340
341  /* other stuff */
342  {"ABORT", s_abort, 0},
343
344  {NULL, NULL, 0}
345};
346