1 /* a.out object file format
2 Copyright (C) 1989-2016 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 c = get_symbol_name (&name);
156 symbolP = symbol_find_or_make (name);
157 (void) restore_line_pointer (c);
158 SKIP_WHITESPACE ();
159 S_SET_WEAK (symbolP);
160 if (c == ',')
161 {
162 input_line_pointer++;
163 SKIP_WHITESPACE ();
164 if (*input_line_pointer == '\n')
165 c = '\n';
166 }
167 }
168 while (c == ',');
169 demand_empty_rest_of_line ();
170 }
171
172 /* Handle .type. On {Net,Open}BSD, this is used to set the n_other field,
173 which is then apparently used when doing dynamic linking. Older
174 versions of gas ignored the .type pseudo-op, so we also ignore it if
175 we can't parse it. */
176
177 static void
obj_aout_type(int ignore ATTRIBUTE_UNUSED)178 obj_aout_type (int ignore ATTRIBUTE_UNUSED)
179 {
180 char *name;
181 int c;
182 symbolS *sym;
183
184 c = get_symbol_name (&name);
185 sym = symbol_find_or_make (name);
186 (void) restore_line_pointer (c);
187 SKIP_WHITESPACE ();
188 if (*input_line_pointer == ',')
189 {
190 ++input_line_pointer;
191 SKIP_WHITESPACE ();
192 if (*input_line_pointer == '@')
193 {
194 ++input_line_pointer;
195 if (strncmp (input_line_pointer, "object", 6) == 0)
196 S_SET_OTHER (sym, 1);
197 else if (strncmp (input_line_pointer, "function", 8) == 0)
198 S_SET_OTHER (sym, 2);
199 }
200 }
201
202 /* Ignore everything else on the line. */
203 s_ignore (0);
204 }
205
206 /* Support for an AOUT emulation. */
207
208 static void
aout_pop_insert(void)209 aout_pop_insert (void)
210 {
211 pop_insert (aout_pseudo_table);
212 }
213
214 static int
obj_aout_s_get_other(symbolS * sym)215 obj_aout_s_get_other (symbolS *sym)
216 {
217 return aout_symbol (symbol_get_bfdsym (sym))->other;
218 }
219
220 static void
obj_aout_s_set_other(symbolS * sym,int o)221 obj_aout_s_set_other (symbolS *sym, int o)
222 {
223 aout_symbol (symbol_get_bfdsym (sym))->other = o;
224 }
225
226 static int
obj_aout_sec_sym_ok_for_reloc(asection * sec ATTRIBUTE_UNUSED)227 obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
228 {
229 return obj_sec_sym_ok_for_reloc (sec);
230 }
231
232 static void
obj_aout_process_stab(segT seg ATTRIBUTE_UNUSED,int w,const char * s,int t,int o,int d)233 obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
234 int w,
235 const char *s,
236 int t,
237 int o,
238 int d)
239 {
240 aout_process_stab (w, s, t, o, d);
241 }
242
243 static int
obj_aout_s_get_desc(symbolS * sym)244 obj_aout_s_get_desc (symbolS *sym)
245 {
246 return aout_symbol (symbol_get_bfdsym (sym))->desc;
247 }
248
249 static void
obj_aout_s_set_desc(symbolS * sym,int d)250 obj_aout_s_set_desc (symbolS *sym, int d)
251 {
252 aout_symbol (symbol_get_bfdsym (sym))->desc = d;
253 }
254
255 static int
obj_aout_s_get_type(symbolS * sym)256 obj_aout_s_get_type (symbolS *sym)
257 {
258 return aout_symbol (symbol_get_bfdsym (sym))->type;
259 }
260
261 static void
obj_aout_s_set_type(symbolS * sym,int t)262 obj_aout_s_set_type (symbolS *sym, int t)
263 {
264 aout_symbol (symbol_get_bfdsym (sym))->type = t;
265 }
266
267 static int
obj_aout_separate_stab_sections(void)268 obj_aout_separate_stab_sections (void)
269 {
270 return 0;
271 }
272
273 /* When changed, make sure these table entries match the single-format
274 definitions in obj-aout.h. */
275
276 const struct format_ops aout_format_ops =
277 {
278 bfd_target_aout_flavour,
279 1, /* dfl_leading_underscore. */
280 0, /* emit_section_symbols. */
281 0, /* begin. */
282 0, /* app_file. */
283 obj_aout_frob_symbol,
284 0, /* frob_file. */
285 0, /* frob_file_before_adjust. */
286 obj_aout_frob_file_before_fix,
287 0, /* frob_file_after_relocs. */
288 0, /* s_get_size. */
289 0, /* s_set_size. */
290 0, /* s_get_align. */
291 0, /* s_set_align. */
292 obj_aout_s_get_other,
293 obj_aout_s_set_other,
294 obj_aout_s_get_desc,
295 obj_aout_s_set_desc,
296 obj_aout_s_get_type,
297 obj_aout_s_set_type,
298 0, /* copy_symbol_attributes. */
299 0, /* generate_asm_lineno. */
300 obj_aout_process_stab,
301 obj_aout_separate_stab_sections,
302 0, /* init_stab_section. */
303 obj_aout_sec_sym_ok_for_reloc,
304 aout_pop_insert,
305 0, /* ecoff_set_ext. */
306 0, /* read_begin_hook. */
307 0, /* symbol_new_hook. */
308 0, /* symbol_clone_hook. */
309 0 /* adjust_symtab. */
310 };
311
312 const pseudo_typeS aout_pseudo_table[] =
313 {
314 {"line", obj_aout_line, 0}, /* Source code line number. */
315 {"ln", obj_aout_line, 0}, /* COFF line number that we use anyway. */
316
317 {"weak", obj_aout_weak, 0}, /* Mark symbol as weak. */
318
319 {"type", obj_aout_type, 0},
320
321 /* coff debug pseudos (ignored) */
322 {"def", s_ignore, 0},
323 {"dim", s_ignore, 0},
324 {"endef", s_ignore, 0},
325 {"ident", s_ignore, 0},
326 {"line", s_ignore, 0},
327 {"ln", s_ignore, 0},
328 {"scl", s_ignore, 0},
329 {"size", s_ignore, 0},
330 {"tag", s_ignore, 0},
331 {"val", s_ignore, 0},
332 {"version", s_ignore, 0},
333
334 {"optim", s_ignore, 0}, /* For sun386i cc (?). */
335
336 /* other stuff */
337 {"ABORT", s_abort, 0},
338
339 {NULL, NULL, 0}
340 };
341