1 /* b.out object file format
2 Copyright (C) 1989, 90, 91, 92, 93, 94, 95, 1996
3 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 2,
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
18 License along with GAS; see the file COPYING. If not, write
19 to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
23 const short /* in: segT out: N_TYPE bits */
32 N_UNDF
, /* expression */
36 N_REGISTER
, /* register */
39 const segT N_TYPE_seg
[N_TYPE
+ 2] =
40 { /* N_TYPE == 0x1E = 32-2 */
41 SEG_UNKNOWN
, /* N_UNDF == 0 */
43 SEG_ABSOLUTE
, /* N_ABS == 2 */
45 SEG_TEXT
, /* N_TEXT == 4 */
47 SEG_DATA
, /* N_DATA == 6 */
49 SEG_BSS
, /* N_BSS == 8 */
51 SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
,
52 SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
,
53 SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
,
54 SEG_REGISTER
, /* dummy N_REGISTER for regs = 30 */
58 static void obj_bout_line
PARAMS ((int));
60 const pseudo_typeS obj_pseudo_table
[] =
62 {"line", obj_bout_line
, 0}, /* source code line number */
64 /* coff debugging directives. Currently ignored silently */
67 {"endef", s_ignore
, 0},
70 {"size", s_ignore
, 0},
72 {"type", s_ignore
, 0},
75 /* other stuff we don't handle */
76 {"ABORT", s_ignore
, 0},
77 {"ident", s_ignore
, 0},
79 {NULL
} /* end sentinel */
80 }; /* obj_pseudo_table */
87 * Crawl along a fixS chain. Emit the segment's relocations.
90 obj_emit_relocations (where
, fixP
, segment_address_in_file
)
92 fixS
*fixP
; /* Fixup chain for this segment. */
93 relax_addressT segment_address_in_file
;
95 for (; fixP
; fixP
= fixP
->fx_next
)
97 if (fixP
->fx_done
== 0
98 || fixP
->fx_r_type
!= NO_RELOC
)
102 sym
= fixP
->fx_addsy
;
103 while (sym
->sy_value
.X_op
== O_symbol
104 && (! S_IS_DEFINED (sym
) || S_IS_COMMON (sym
)))
105 sym
= sym
->sy_value
.X_add_symbol
;
106 fixP
->fx_addsy
= sym
;
108 tc_bout_fix_to_chars (*where
, fixP
, segment_address_in_file
);
109 *where
+= sizeof (struct relocation_info
);
110 } /* if there's a symbol */
111 } /* for each fixup */
113 } /* emit_relocations() */
115 /* Aout file generation & utilities */
117 /* Convert a lvalue to machine dependent data */
119 obj_header_append (where
, headers
)
121 object_headers
*headers
;
123 /* Always leave in host byte order */
125 headers
->header
.a_talign
= section_alignment
[SEG_TEXT
];
127 if (headers
->header
.a_talign
< 2)
129 headers
->header
.a_talign
= 2;
130 } /* force to at least 2 */
132 headers
->header
.a_dalign
= section_alignment
[SEG_DATA
];
133 headers
->header
.a_balign
= section_alignment
[SEG_BSS
];
135 headers
->header
.a_tload
= 0;
136 headers
->header
.a_dload
= md_section_align (SEG_DATA
, H_GET_TEXT_SIZE (headers
));
138 headers
->header
.a_relaxable
= linkrelax
;
141 md_number_to_chars (*where
, headers
->header
.a_magic
, sizeof (headers
->header
.a_magic
));
142 *where
+= sizeof (headers
->header
.a_magic
);
143 md_number_to_chars (*where
, headers
->header
.a_text
, sizeof (headers
->header
.a_text
));
144 *where
+= sizeof (headers
->header
.a_text
);
145 md_number_to_chars (*where
, headers
->header
.a_data
, sizeof (headers
->header
.a_data
));
146 *where
+= sizeof (headers
->header
.a_data
);
147 md_number_to_chars (*where
, headers
->header
.a_bss
, sizeof (headers
->header
.a_bss
));
148 *where
+= sizeof (headers
->header
.a_bss
);
149 md_number_to_chars (*where
, headers
->header
.a_syms
, sizeof (headers
->header
.a_syms
));
150 *where
+= sizeof (headers
->header
.a_syms
);
151 md_number_to_chars (*where
, headers
->header
.a_entry
, sizeof (headers
->header
.a_entry
));
152 *where
+= sizeof (headers
->header
.a_entry
);
153 md_number_to_chars (*where
, headers
->header
.a_trsize
, sizeof (headers
->header
.a_trsize
));
154 *where
+= sizeof (headers
->header
.a_trsize
);
155 md_number_to_chars (*where
, headers
->header
.a_drsize
, sizeof (headers
->header
.a_drsize
));
156 *where
+= sizeof (headers
->header
.a_drsize
);
157 md_number_to_chars (*where
, headers
->header
.a_tload
, sizeof (headers
->header
.a_tload
));
158 *where
+= sizeof (headers
->header
.a_tload
);
159 md_number_to_chars (*where
, headers
->header
.a_dload
, sizeof (headers
->header
.a_dload
));
160 *where
+= sizeof (headers
->header
.a_dload
);
161 md_number_to_chars (*where
, headers
->header
.a_talign
, sizeof (headers
->header
.a_talign
));
162 *where
+= sizeof (headers
->header
.a_talign
);
163 md_number_to_chars (*where
, headers
->header
.a_dalign
, sizeof (headers
->header
.a_dalign
));
164 *where
+= sizeof (headers
->header
.a_dalign
);
165 md_number_to_chars (*where
, headers
->header
.a_balign
, sizeof (headers
->header
.a_balign
));
166 *where
+= sizeof (headers
->header
.a_balign
);
167 md_number_to_chars (*where
, headers
->header
.a_relaxable
, sizeof (headers
->header
.a_relaxable
));
168 *where
+= sizeof (headers
->header
.a_relaxable
);
169 #else /* ! CROSS_COMPILE */
170 append (where
, (char *) &headers
->header
, sizeof (headers
->header
));
171 #endif /* ! CROSS_COMPILE */
172 } /* a_header_append() */
175 obj_symbol_to_chars (where
, symbolP
)
179 md_number_to_chars ((char *) &(S_GET_OFFSET (symbolP
)), S_GET_OFFSET (symbolP
), sizeof (S_GET_OFFSET (symbolP
)));
180 md_number_to_chars ((char *) &(S_GET_DESC (symbolP
)), S_GET_DESC (symbolP
), sizeof (S_GET_DESC (symbolP
)));
181 md_number_to_chars ((char *) &symbolP
->sy_symbol
.n_value
, S_GET_VALUE (symbolP
), sizeof (symbolP
->sy_symbol
.n_value
));
183 append (where
, (char *) &symbolP
->sy_symbol
, sizeof (obj_symbol_type
));
184 } /* obj_symbol_to_chars() */
187 obj_emit_symbols (where
, symbol_rootP
)
189 symbolS
*symbol_rootP
;
194 * Emit all symbols left in the symbol chain.
196 for (symbolP
= symbol_rootP
; symbolP
; symbolP
= symbol_next (symbolP
))
198 /* Used to save the offset of the name. It is used to point
199 to the string in memory but must be a file offset. */
202 temp
= S_GET_NAME (symbolP
);
203 S_SET_OFFSET (symbolP
, symbolP
->sy_name_offset
);
205 /* Any symbol still undefined and is not a dbg symbol is made N_EXT. */
206 if (!S_IS_DEBUG (symbolP
) && !S_IS_DEFINED (symbolP
))
207 S_SET_EXTERNAL (symbolP
);
209 obj_symbol_to_chars (where
, symbolP
);
210 S_SET_NAME (symbolP
, temp
);
212 } /* emit_symbols() */
215 obj_symbol_new_hook (symbolP
)
218 S_SET_OTHER (symbolP
, 0);
219 S_SET_DESC (symbolP
, 0);
223 obj_bout_line (ignore
)
226 /* Assume delimiter is part of expression. */
227 /* BSD4.2 as fails with delightful bug, so we */
228 /* are not being incompatible here. */
229 new_logical_line ((char *) NULL
, (int) (get_absolute_expression ()));
230 demand_empty_rest_of_line ();
231 } /* obj_bout_line() */
234 obj_read_begin_hook ()
239 obj_crawl_symbol_chain (headers
)
240 object_headers
*headers
;
244 int symbol_number
= 0;
246 tc_crawl_symbol_chain (headers
);
248 symbolPP
= &symbol_rootP
; /*->last symbol chain link. */
249 while ((symbolP
= *symbolPP
) != NULL
)
251 if (flag_readonly_data_in_text
&& (S_GET_SEGMENT (symbolP
) == SEG_DATA
))
253 S_SET_SEGMENT (symbolP
, SEG_TEXT
);
254 } /* if pusing data into text */
256 resolve_symbol_value (symbolP
, 1);
258 /* Skip symbols which were equated to undefined or common
260 if (symbolP
->sy_value
.X_op
== O_symbol
261 && (! S_IS_DEFINED (symbolP
) || S_IS_COMMON (symbolP
)))
263 *symbolPP
= symbol_next (symbolP
);
267 /* OK, here is how we decide which symbols go out into the
268 brave new symtab. Symbols that do are:
270 * symbols with no name (stabd's?)
271 * symbols with debug info in their N_TYPE
273 Symbols that don't are:
274 * symbols that are registers
275 * symbols with \1 as their 3rd character (numeric labels)
276 * "local labels" as defined by S_LOCAL_NAME(name)
277 if the -L switch was passed to gas.
279 All other symbols are output. We complain if a deleted
280 symbol was marked external. */
284 && !S_IS_REGISTER (symbolP
)
285 && (!S_GET_NAME (symbolP
)
286 || S_IS_DEBUG (symbolP
)
288 /* FIXME-SOON this ifdef seems highly dubious to me. xoxorich. */
289 || !S_IS_DEFINED (symbolP
)
290 || S_IS_EXTERNAL (symbolP
)
292 || (S_GET_NAME (symbolP
)[0] != '\001' && (flag_keep_locals
|| !S_LOCAL_NAME (symbolP
)))))
294 symbolP
->sy_number
= symbol_number
++;
296 /* The + 1 after strlen account for the \0 at the
297 end of each string */
298 if (!S_IS_STABD (symbolP
))
301 symbolP
->sy_name_offset
= string_byte_count
;
302 string_byte_count
+= strlen (S_GET_NAME (symbolP
)) + 1;
304 else /* .Stabd case. */
305 symbolP
->sy_name_offset
= 0;
306 symbolPP
= &(symbol_next (symbolP
));
310 if (S_IS_EXTERNAL (symbolP
) || !S_IS_DEFINED (symbolP
))
312 as_bad (_("Local symbol %s never defined"), S_GET_NAME (symbolP
));
315 /* Unhook it from the chain */
316 *symbolPP
= symbol_next (symbolP
);
317 } /* if this symbol should be in the output */
318 } /* for each symbol */
320 H_SET_SYMBOL_TABLE_SIZE (headers
, symbol_number
);
324 * Find strings by crawling along symbol table chain.
328 obj_emit_strings (where
)
334 /* Gotta do md_ byte-ordering stuff for string_byte_count first - KWK */
335 md_number_to_chars (*where
, string_byte_count
, sizeof (string_byte_count
));
336 *where
+= sizeof (string_byte_count
);
337 #else /* CROSS_COMPILE */
338 append (where
, (char *) &string_byte_count
, (unsigned long) sizeof (string_byte_count
));
339 #endif /* CROSS_COMPILE */
341 for (symbolP
= symbol_rootP
; symbolP
; symbolP
= symbol_next (symbolP
))
343 if (S_GET_NAME (symbolP
))
344 append (where
, S_GET_NAME (symbolP
), (unsigned long) (strlen (S_GET_NAME (symbolP
)) + 1));
345 } /* walk symbol chain */
348 /* end of obj-bout.c */