1/* a.out object file format
2   Copyright (C) 1989-2020 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
8   published by the Free Software Foundation; either version 3,
9   or (at your option) any later version.
10
11   GAS is distributed in the hope that it will be useful, but
12   WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
14   the 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#define OBJ_HEADER "obj-aout.h"
22
23#include "as.h"
24#undef NO_RELOC
25#include "aout/aout64.h"
26
27void
28obj_aout_frob_symbol (symbolS *sym, int *punt ATTRIBUTE_UNUSED)
29{
30  flagword flags;
31  asection *sec;
32  int type;
33
34  flags = symbol_get_bfdsym (sym)->flags;
35  type = aout_symbol (symbol_get_bfdsym (sym))->type;
36  sec = S_GET_SEGMENT (sym);
37
38  /* Only frob simple symbols this way right now.  */
39  if (! (type & ~ (N_TYPE | N_EXT)))
40    {
41      if (type == (N_UNDF | N_EXT)
42	  && sec == bfd_abs_section_ptr)
43	{
44	  sec = bfd_und_section_ptr;
45	  S_SET_SEGMENT (sym, sec);
46	}
47
48      if ((type & N_TYPE) != N_INDR
49	  && (type & N_TYPE) != N_SETA
50	  && (type & N_TYPE) != N_SETT
51	  && (type & N_TYPE) != N_SETD
52	  && (type & N_TYPE) != N_SETB
53	  && type != N_WARNING
54	  && (sec == bfd_abs_section_ptr
55	      || sec == bfd_und_section_ptr))
56	return;
57      if (flags & BSF_EXPORT)
58	type |= N_EXT;
59
60      switch (type & N_TYPE)
61	{
62	case N_SETA:
63	case N_SETT:
64	case N_SETD:
65	case N_SETB:
66	  /* Set the debugging flag for constructor symbols so that
67	     BFD leaves them alone.  */
68	  symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
69
70	  /* You can't put a common symbol in a set.  The way a set
71	     element works is that the symbol has a definition and a
72	     name, and the linker adds the definition to the set of
73	     that name.  That does not work for a common symbol,
74	     because the linker can't tell which common symbol the
75	     user means.  FIXME: Using as_bad here may be
76	     inappropriate, since the user may want to force a
77	     particular type without regard to the semantics of sets;
78	     on the other hand, we certainly don't want anybody to be
79	     mislead into thinking that their code will work.  */
80	  if (S_IS_COMMON (sym))
81	    as_bad (_("Attempt to put a common symbol into set %s"),
82		    S_GET_NAME (sym));
83	  /* Similarly, you can't put an undefined symbol in a set.  */
84	  else if (! S_IS_DEFINED (sym))
85	    as_bad (_("Attempt to put an undefined symbol into set %s"),
86		    S_GET_NAME (sym));
87
88	  break;
89	case N_INDR:
90	  /* Put indirect symbols in the indirect section.  */
91	  S_SET_SEGMENT (sym, bfd_ind_section_ptr);
92	  symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT;
93	  if (type & N_EXT)
94	    {
95	      symbol_get_bfdsym (sym)->flags |= BSF_EXPORT;
96	      symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL;
97	    }
98	  break;
99	case N_WARNING:
100	  /* Mark warning symbols.  */
101	  symbol_get_bfdsym (sym)->flags |= BSF_WARNING;
102	  break;
103	}
104    }
105  else
106    symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
107
108  aout_symbol (symbol_get_bfdsym (sym))->type = type;
109
110  /* Double check weak symbols.  */
111  if (S_IS_WEAK (sym) && S_IS_COMMON (sym))
112    as_bad (_("Symbol `%s' can not be both weak and common"),
113	    S_GET_NAME (sym));
114}
115
116void
117obj_aout_frob_file_before_fix (void)
118{
119  /* Relocation processing may require knowing the VMAs of the sections.
120     Since writing to a section will cause the BFD back end to compute the
121     VMAs, fake it out here....
122     Writing to the end of the section ensures the file contents
123     extend to cover the entire aligned size.  We possibly won't know
124     the aligned size until after VMAs and sizes are set on the first
125     bfd_set_section_contents call, so it might be necessary to repeat.  */
126  asection *sec = NULL;
127  if (data_section->size != 0)
128    sec = data_section;
129  else if (text_section->size != 0)
130    sec = text_section;
131  if (sec)
132    {
133      bfd_size_type size;
134      do
135	{
136	  bfd_byte b = 0;
137	  size = sec->size;
138	  gas_assert (bfd_set_section_contents (stdoutput, sec, &b,
139						size - 1, (bfd_size_type) 1));
140	} while (size != sec->size);
141    }
142}
143
144static void
145obj_aout_line (int ignore ATTRIBUTE_UNUSED)
146{
147  /* Assume delimiter is part of expression.
148     BSD4.2 as fails with delightful bug, so we
149     are not being incompatible here.  */
150  new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
151  demand_empty_rest_of_line ();
152}
153
154/* Handle .weak.  This is a GNU extension.  */
155
156static void
157obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
158{
159  char *name;
160  int c;
161  symbolS *symbolP;
162
163  do
164    {
165      c = get_symbol_name (&name);
166      symbolP = symbol_find_or_make (name);
167      (void) restore_line_pointer (c);
168      SKIP_WHITESPACE ();
169      S_SET_WEAK (symbolP);
170      if (c == ',')
171	{
172	  input_line_pointer++;
173	  SKIP_WHITESPACE ();
174	  if (*input_line_pointer == '\n')
175	    c = '\n';
176	}
177    }
178  while (c == ',');
179  demand_empty_rest_of_line ();
180}
181
182/* Handle .type.  On {Net,Open}BSD, this is used to set the n_other field,
183   which is then apparently used when doing dynamic linking.  Older
184   versions of gas ignored the .type pseudo-op, so we also ignore it if
185   we can't parse it.  */
186
187static void
188obj_aout_type (int ignore ATTRIBUTE_UNUSED)
189{
190  char *name;
191  int c;
192  symbolS *sym;
193
194  c = get_symbol_name (&name);
195  sym = symbol_find_or_make (name);
196  (void) restore_line_pointer (c);
197  SKIP_WHITESPACE ();
198  if (*input_line_pointer == ',')
199    {
200      ++input_line_pointer;
201      SKIP_WHITESPACE ();
202      if (*input_line_pointer == '@')
203	{
204	  ++input_line_pointer;
205	  if (strncmp (input_line_pointer, "object", 6) == 0)
206	    S_SET_OTHER (sym, 1);
207	  else if (strncmp (input_line_pointer, "function", 8) == 0)
208	    S_SET_OTHER (sym, 2);
209	}
210    }
211
212  /* Ignore everything else on the line.  */
213  s_ignore (0);
214}
215
216/* Support for an AOUT emulation.  */
217
218static void
219aout_pop_insert (void)
220{
221  pop_insert (aout_pseudo_table);
222}
223
224static int
225obj_aout_s_get_other (symbolS *sym)
226{
227  return aout_symbol (symbol_get_bfdsym (sym))->other;
228}
229
230static void
231obj_aout_s_set_other (symbolS *sym, int o)
232{
233  aout_symbol (symbol_get_bfdsym (sym))->other = o;
234}
235
236static int
237obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
238{
239  return obj_sec_sym_ok_for_reloc (sec);
240}
241
242static void
243obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
244		       int w,
245		       const char *s,
246		       int t,
247		       int o,
248		       int d)
249{
250  aout_process_stab (w, s, t, o, d);
251}
252
253static int
254obj_aout_s_get_desc (symbolS *sym)
255{
256  return aout_symbol (symbol_get_bfdsym (sym))->desc;
257}
258
259static void
260obj_aout_s_set_desc (symbolS *sym, int d)
261{
262  aout_symbol (symbol_get_bfdsym (sym))->desc = d;
263}
264
265static int
266obj_aout_s_get_type (symbolS *sym)
267{
268  return aout_symbol (symbol_get_bfdsym (sym))->type;
269}
270
271static void
272obj_aout_s_set_type (symbolS *sym, int t)
273{
274  aout_symbol (symbol_get_bfdsym (sym))->type = t;
275}
276
277static int
278obj_aout_separate_stab_sections (void)
279{
280  return 0;
281}
282
283/* When changed, make sure these table entries match the single-format
284   definitions in obj-aout.h.  */
285
286const struct format_ops aout_format_ops =
287{
288  bfd_target_aout_flavour,
289  1,	/* dfl_leading_underscore.  */
290  0,	/* emit_section_symbols.  */
291  0,	/* begin.  */
292  0,	/* app_file.  */
293  obj_aout_frob_symbol,
294  0,	/* frob_file.  */
295  0,	/* frob_file_before_adjust.  */
296  obj_aout_frob_file_before_fix,
297  0,	/* frob_file_after_relocs.  */
298  0,	/* s_get_size.  */
299  0,	/* s_set_size.  */
300  0,	/* s_get_align.  */
301  0,	/* s_set_align.  */
302  obj_aout_s_get_other,
303  obj_aout_s_set_other,
304  obj_aout_s_get_desc,
305  obj_aout_s_set_desc,
306  obj_aout_s_get_type,
307  obj_aout_s_set_type,
308  0,	/* copy_symbol_attributes.  */
309  0,	/* generate_asm_lineno.  */
310  obj_aout_process_stab,
311  obj_aout_separate_stab_sections,
312  0,	/* init_stab_section.  */
313  obj_aout_sec_sym_ok_for_reloc,
314  aout_pop_insert,
315  0,	/* ecoff_set_ext.  */
316  0,	/* read_begin_hook.  */
317  0,	/* symbol_new_hook.  */
318  0,	/* symbol_clone_hook.  */
319  0	/* adjust_symtab.  */
320};
321
322const pseudo_typeS aout_pseudo_table[] =
323{
324  {"line", obj_aout_line, 0},	/* Source code line number.  */
325  {"ln", obj_aout_line, 0},	/* COFF line number that we use anyway.  */
326
327  {"weak", obj_aout_weak, 0},	/* Mark symbol as weak.  */
328
329  {"type", obj_aout_type, 0},
330
331  /* coff debug pseudos (ignored) */
332  {"def", s_ignore, 0},
333  {"dim", s_ignore, 0},
334  {"endef", s_ignore, 0},
335  {"ident", s_ignore, 0},
336  {"line", s_ignore, 0},
337  {"ln", s_ignore, 0},
338  {"scl", s_ignore, 0},
339  {"size", s_ignore, 0},
340  {"tag", s_ignore, 0},
341  {"val", s_ignore, 0},
342  {"version", s_ignore, 0},
343
344  {"optim", s_ignore, 0},	/* For sun386i cc (?).  */
345
346  /* other stuff */
347  {"ABORT", s_abort, 0},
348
349  {NULL, NULL, 0}
350};
351