1 /* a.out object file format
2 Copyright (C) 1989-2014 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
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
27 void
obj_aout_frob_symbol(symbolS * sym,int * punt ATTRIBUTE_UNUSED)28 obj_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
116 void
obj_aout_frob_file_before_fix(void)117 obj_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 bfd_byte b = 0;
123 bfd_boolean x = TRUE;
124 if (bfd_section_size (stdoutput, text_section) != 0)
125 x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0,
126 (bfd_size_type) 1);
127 else if (bfd_section_size (stdoutput, data_section) != 0)
128 x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0,
129 (bfd_size_type) 1);
130
131 gas_assert (x);
132 }
133
134 static void
obj_aout_line(int ignore ATTRIBUTE_UNUSED)135 obj_aout_line (int ignore ATTRIBUTE_UNUSED)
136 {
137 /* Assume delimiter is part of expression.
138 BSD4.2 as fails with delightful bug, so we
139 are not being incompatible here. */
140 new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
141 demand_empty_rest_of_line ();
142 }
143
144 /* Handle .weak. This is a GNU extension. */
145
146 static void
obj_aout_weak(int ignore ATTRIBUTE_UNUSED)147 obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
148 {
149 char *name;
150 int c;
151 symbolS *symbolP;
152
153 do
154 {
155 name = input_line_pointer;
156 c = get_symbol_end ();
157 symbolP = symbol_find_or_make (name);
158 *input_line_pointer = c;
159 SKIP_WHITESPACE ();
160 S_SET_WEAK (symbolP);
161 if (c == ',')
162 {
163 input_line_pointer++;
164 SKIP_WHITESPACE ();
165 if (*input_line_pointer == '\n')
166 c = '\n';
167 }
168 }
169 while (c == ',');
170 demand_empty_rest_of_line ();
171 }
172
173 /* Handle .type. On {Net,Open}BSD, this is used to set the n_other field,
174 which is then apparently used when doing dynamic linking. Older
175 versions of gas ignored the .type pseudo-op, so we also ignore it if
176 we can't parse it. */
177
178 static void
obj_aout_type(int ignore ATTRIBUTE_UNUSED)179 obj_aout_type (int ignore ATTRIBUTE_UNUSED)
180 {
181 char *name;
182 int c;
183 symbolS *sym;
184
185 name = input_line_pointer;
186 c = get_symbol_end ();
187 sym = symbol_find_or_make (name);
188 *input_line_pointer = c;
189 SKIP_WHITESPACE ();
190 if (*input_line_pointer == ',')
191 {
192 ++input_line_pointer;
193 SKIP_WHITESPACE ();
194 if (*input_line_pointer == '@')
195 {
196 ++input_line_pointer;
197 if (strncmp (input_line_pointer, "object", 6) == 0)
198 S_SET_OTHER (sym, 1);
199 else if (strncmp (input_line_pointer, "function", 8) == 0)
200 S_SET_OTHER (sym, 2);
201 }
202 }
203
204 /* Ignore everything else on the line. */
205 s_ignore (0);
206 }
207
208 /* Support for an AOUT emulation. */
209
210 static void
aout_pop_insert(void)211 aout_pop_insert (void)
212 {
213 pop_insert (aout_pseudo_table);
214 }
215
216 static int
obj_aout_s_get_other(symbolS * sym)217 obj_aout_s_get_other (symbolS *sym)
218 {
219 return aout_symbol (symbol_get_bfdsym (sym))->other;
220 }
221
222 static void
obj_aout_s_set_other(symbolS * sym,int o)223 obj_aout_s_set_other (symbolS *sym, int o)
224 {
225 aout_symbol (symbol_get_bfdsym (sym))->other = o;
226 }
227
228 static int
obj_aout_sec_sym_ok_for_reloc(asection * sec ATTRIBUTE_UNUSED)229 obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
230 {
231 return obj_sec_sym_ok_for_reloc (sec);
232 }
233
234 static void
obj_aout_process_stab(segT seg ATTRIBUTE_UNUSED,int w,const char * s,int t,int o,int d)235 obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
236 int w,
237 const char *s,
238 int t,
239 int o,
240 int d)
241 {
242 aout_process_stab (w, s, t, o, d);
243 }
244
245 static int
obj_aout_s_get_desc(symbolS * sym)246 obj_aout_s_get_desc (symbolS *sym)
247 {
248 return aout_symbol (symbol_get_bfdsym (sym))->desc;
249 }
250
251 static void
obj_aout_s_set_desc(symbolS * sym,int d)252 obj_aout_s_set_desc (symbolS *sym, int d)
253 {
254 aout_symbol (symbol_get_bfdsym (sym))->desc = d;
255 }
256
257 static int
obj_aout_s_get_type(symbolS * sym)258 obj_aout_s_get_type (symbolS *sym)
259 {
260 return aout_symbol (symbol_get_bfdsym (sym))->type;
261 }
262
263 static void
obj_aout_s_set_type(symbolS * sym,int t)264 obj_aout_s_set_type (symbolS *sym, int t)
265 {
266 aout_symbol (symbol_get_bfdsym (sym))->type = t;
267 }
268
269 static int
obj_aout_separate_stab_sections(void)270 obj_aout_separate_stab_sections (void)
271 {
272 return 0;
273 }
274
275 /* When changed, make sure these table entries match the single-format
276 definitions in obj-aout.h. */
277
278 const struct format_ops aout_format_ops =
279 {
280 bfd_target_aout_flavour,
281 1, /* dfl_leading_underscore. */
282 0, /* emit_section_symbols. */
283 0, /* begin. */
284 0, /* app_file. */
285 obj_aout_frob_symbol,
286 0, /* frob_file. */
287 0, /* frob_file_before_adjust. */
288 obj_aout_frob_file_before_fix,
289 0, /* frob_file_after_relocs. */
290 0, /* s_get_size. */
291 0, /* s_set_size. */
292 0, /* s_get_align. */
293 0, /* s_set_align. */
294 obj_aout_s_get_other,
295 obj_aout_s_set_other,
296 obj_aout_s_get_desc,
297 obj_aout_s_set_desc,
298 obj_aout_s_get_type,
299 obj_aout_s_set_type,
300 0, /* copy_symbol_attributes. */
301 0, /* generate_asm_lineno. */
302 obj_aout_process_stab,
303 obj_aout_separate_stab_sections,
304 0, /* init_stab_section. */
305 obj_aout_sec_sym_ok_for_reloc,
306 aout_pop_insert,
307 0, /* ecoff_set_ext. */
308 0, /* read_begin_hook. */
309 0, /* symbol_new_hook. */
310 0, /* symbol_clone_hook. */
311 0 /* adjust_symtab. */
312 };
313
314 const pseudo_typeS aout_pseudo_table[] =
315 {
316 {"line", obj_aout_line, 0}, /* Source code line number. */
317 {"ln", obj_aout_line, 0}, /* COFF line number that we use anyway. */
318
319 {"weak", obj_aout_weak, 0}, /* Mark symbol as weak. */
320
321 {"type", obj_aout_type, 0},
322
323 /* coff debug pseudos (ignored) */
324 {"def", s_ignore, 0},
325 {"dim", s_ignore, 0},
326 {"endef", s_ignore, 0},
327 {"ident", s_ignore, 0},
328 {"line", s_ignore, 0},
329 {"ln", s_ignore, 0},
330 {"scl", s_ignore, 0},
331 {"size", s_ignore, 0},
332 {"tag", s_ignore, 0},
333 {"val", s_ignore, 0},
334 {"version", s_ignore, 0},
335
336 {"optim", s_ignore, 0}, /* For sun386i cc (?). */
337
338 /* other stuff */
339 {"ABORT", s_abort, 0},
340
341 {NULL, NULL, 0}
342 };
343