1 /* b.out object file format
2 Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1996, 2000, 2001, 2002
3 Free Software Foundation, Inc.
4
5 This file is part of GAS, the GNU Assembler.
6
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.
11
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.
16
17 You should have received a copy of the GNU General Public License
18 along with GAS; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
21
22 #include "as.h"
23 #include "obstack.h"
24
25 /* In: segT Out: N_TYPE bits */
26 const short seg_N_TYPE[] =
27 {
28 N_ABS,
29 N_TEXT,
30 N_DATA,
31 N_BSS,
32 N_UNDF, /* unknown */
33 N_UNDF, /* error */
34 N_UNDF, /* expression */
35 N_UNDF, /* debug */
36 N_UNDF, /* ntv */
37 N_UNDF, /* ptv */
38 N_REGISTER, /* register */
39 };
40
41 const segT N_TYPE_seg[N_TYPE + 2] =
42 { /* N_TYPE == 0x1E = 32-2 */
43 SEG_UNKNOWN, /* N_UNDF == 0 */
44 SEG_GOOF,
45 SEG_ABSOLUTE, /* N_ABS == 2 */
46 SEG_GOOF,
47 SEG_TEXT, /* N_TEXT == 4 */
48 SEG_GOOF,
49 SEG_DATA, /* N_DATA == 6 */
50 SEG_GOOF,
51 SEG_BSS, /* N_BSS == 8 */
52 SEG_GOOF,
53 SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
54 SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
55 SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
56 SEG_REGISTER, /* dummy N_REGISTER for regs = 30 */
57 SEG_GOOF,
58 };
59
60 static void obj_bout_line PARAMS ((int));
61
62 const pseudo_typeS obj_pseudo_table[] =
63 {
64 {"line", obj_bout_line, 0}, /* Source code line number. */
65
66 /* coff debugging directives. Currently ignored silently. */
67 {"def", s_ignore, 0},
68 {"dim", s_ignore, 0},
69 {"endef", s_ignore, 0},
70 {"ln", s_ignore, 0},
71 {"scl", s_ignore, 0},
72 {"size", s_ignore, 0},
73 {"tag", s_ignore, 0},
74 {"type", s_ignore, 0},
75 {"val", s_ignore, 0},
76
77 /* other stuff we don't handle */
78 {"ABORT", s_ignore, 0},
79 {"ident", s_ignore, 0},
80
81 {NULL, NULL, 0} /* End sentinel. */
82 };
83
84 /* Relocation. */
85
86 /* Crawl along a fixS chain. Emit the segment's relocations. */
87
88 void
obj_emit_relocations(where,fixP,segment_address_in_file)89 obj_emit_relocations (where, fixP, segment_address_in_file)
90 char **where;
91 fixS *fixP; /* Fixup chain for this segment. */
92 relax_addressT segment_address_in_file;
93 {
94 for (; fixP; fixP = fixP->fx_next)
95 {
96 if (fixP->fx_done == 0
97 || fixP->fx_r_type != NO_RELOC)
98 {
99 symbolS *sym;
100
101 sym = fixP->fx_addsy;
102 while (sym->sy_value.X_op == O_symbol
103 && (! S_IS_DEFINED (sym) || S_IS_COMMON (sym)))
104 sym = sym->sy_value.X_add_symbol;
105 fixP->fx_addsy = sym;
106
107 tc_bout_fix_to_chars (*where, fixP, segment_address_in_file);
108 *where += sizeof (struct relocation_info);
109 } /* if there's a symbol */
110 } /* for each fixup */
111 }
112
113 /* Aout file generation & utilities . */
114
115 /* Convert a lvalue to machine dependent data. */
116
117 void
obj_header_append(where,headers)118 obj_header_append (where, headers)
119 char **where;
120 object_headers *headers;
121 {
122 /* Always leave in host byte order. */
123
124 headers->header.a_talign = section_alignment[SEG_TEXT];
125
126 /* Force to at least 2. */
127 if (headers->header.a_talign < 2)
128 {
129 headers->header.a_talign = 2;
130 }
131
132 headers->header.a_dalign = section_alignment[SEG_DATA];
133 headers->header.a_balign = section_alignment[SEG_BSS];
134
135 headers->header.a_tload = 0;
136 headers->header.a_dload =
137 md_section_align (SEG_DATA, H_GET_TEXT_SIZE (headers));
138
139 headers->header.a_relaxable = linkrelax;
140
141 #ifdef CROSS_COMPILE
142 md_number_to_chars (*where, headers->header.a_magic, sizeof (headers->header.a_magic));
143 *where += sizeof (headers->header.a_magic);
144 md_number_to_chars (*where, headers->header.a_text, sizeof (headers->header.a_text));
145 *where += sizeof (headers->header.a_text);
146 md_number_to_chars (*where, headers->header.a_data, sizeof (headers->header.a_data));
147 *where += sizeof (headers->header.a_data);
148 md_number_to_chars (*where, headers->header.a_bss, sizeof (headers->header.a_bss));
149 *where += sizeof (headers->header.a_bss);
150 md_number_to_chars (*where, headers->header.a_syms, sizeof (headers->header.a_syms));
151 *where += sizeof (headers->header.a_syms);
152 md_number_to_chars (*where, headers->header.a_entry, sizeof (headers->header.a_entry));
153 *where += sizeof (headers->header.a_entry);
154 md_number_to_chars (*where, headers->header.a_trsize, sizeof (headers->header.a_trsize));
155 *where += sizeof (headers->header.a_trsize);
156 md_number_to_chars (*where, headers->header.a_drsize, sizeof (headers->header.a_drsize));
157 *where += sizeof (headers->header.a_drsize);
158 md_number_to_chars (*where, headers->header.a_tload, sizeof (headers->header.a_tload));
159 *where += sizeof (headers->header.a_tload);
160 md_number_to_chars (*where, headers->header.a_dload, sizeof (headers->header.a_dload));
161 *where += sizeof (headers->header.a_dload);
162 md_number_to_chars (*where, headers->header.a_talign, sizeof (headers->header.a_talign));
163 *where += sizeof (headers->header.a_talign);
164 md_number_to_chars (*where, headers->header.a_dalign, sizeof (headers->header.a_dalign));
165 *where += sizeof (headers->header.a_dalign);
166 md_number_to_chars (*where, headers->header.a_balign, sizeof (headers->header.a_balign));
167 *where += sizeof (headers->header.a_balign);
168 md_number_to_chars (*where, headers->header.a_relaxable, sizeof (headers->header.a_relaxable));
169 *where += sizeof (headers->header.a_relaxable);
170 #else /* ! CROSS_COMPILE */
171 append (where, (char *) &headers->header, sizeof (headers->header));
172 #endif /* ! CROSS_COMPILE */
173 }
174
175 void
obj_symbol_to_chars(where,symbolP)176 obj_symbol_to_chars (where, symbolP)
177 char **where;
178 symbolS *symbolP;
179 {
180 md_number_to_chars ((char *) &(S_GET_OFFSET (symbolP)),
181 S_GET_OFFSET (symbolP),
182 sizeof (S_GET_OFFSET (symbolP)));
183
184 md_number_to_chars ((char *) &(S_GET_DESC (symbolP)),
185 S_GET_DESC (symbolP),
186 sizeof (S_GET_DESC (symbolP)));
187
188 md_number_to_chars ((char *) &symbolP->sy_symbol.n_value,
189 S_GET_VALUE (symbolP),
190 sizeof (symbolP->sy_symbol.n_value));
191
192 append (where, (char *) &symbolP->sy_symbol, sizeof (obj_symbol_type));
193 }
194
195 void
obj_emit_symbols(where,symbol_rootP)196 obj_emit_symbols (where, symbol_rootP)
197 char **where;
198 symbolS *symbol_rootP;
199 {
200 symbolS *symbolP;
201
202 /* Emit all symbols left in the symbol chain. */
203 for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP))
204 {
205 /* Used to save the offset of the name. It is used to point to
206 the string in memory but must be a file offset. */
207 char *temp;
208
209 temp = S_GET_NAME (symbolP);
210 S_SET_OFFSET (symbolP, symbolP->sy_name_offset);
211
212 /* Any symbol still undefined and is not a dbg symbol is made N_EXT. */
213 if (!S_IS_DEBUG (symbolP) && !S_IS_DEFINED (symbolP))
214 S_SET_EXTERNAL (symbolP);
215
216 obj_symbol_to_chars (where, symbolP);
217 S_SET_NAME (symbolP, temp);
218 }
219 }
220
221 void
obj_symbol_new_hook(symbolP)222 obj_symbol_new_hook (symbolP)
223 symbolS *symbolP;
224 {
225 S_SET_OTHER (symbolP, 0);
226 S_SET_DESC (symbolP, 0);
227 }
228
229 static void
obj_bout_line(ignore)230 obj_bout_line (ignore)
231 int ignore ATTRIBUTE_UNUSED;
232 {
233 /* Assume delimiter is part of expression. */
234 /* BSD4.2 as fails with delightful bug, so we are not being
235 incompatible here. */
236 new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
237 demand_empty_rest_of_line ();
238 }
239
240 void
obj_read_begin_hook()241 obj_read_begin_hook ()
242 {
243 }
244
245 void
obj_crawl_symbol_chain(headers)246 obj_crawl_symbol_chain (headers)
247 object_headers *headers;
248 {
249 symbolS **symbolPP;
250 symbolS *symbolP;
251 int symbol_number = 0;
252
253 tc_crawl_symbol_chain (headers);
254
255 symbolPP = &symbol_rootP; /* -> last symbol chain link. */
256 while ((symbolP = *symbolPP) != NULL)
257 {
258 if (flag_readonly_data_in_text && (S_GET_SEGMENT (symbolP) == SEG_DATA))
259 {
260 S_SET_SEGMENT (symbolP, SEG_TEXT);
261 } /* if pushing data into text */
262
263 resolve_symbol_value (symbolP);
264
265 /* Skip symbols which were equated to undefined or common
266 symbols. */
267 if (symbolP->sy_value.X_op == O_symbol
268 && (! S_IS_DEFINED (symbolP) || S_IS_COMMON (symbolP)))
269 {
270 *symbolPP = symbol_next (symbolP);
271 continue;
272 }
273
274 /* OK, here is how we decide which symbols go out into the
275 brave new symtab. Symbols that do are:
276
277 * symbols with no name (stabd's?)
278 * symbols with debug info in their N_TYPE
279
280 Symbols that don't are:
281 * symbols that are registers
282 * symbols with \1 as their 3rd character (numeric labels)
283 * "local labels" as defined by S_LOCAL_NAME(name)
284 if the -L switch was passed to gas.
285
286 All other symbols are output. We complain if a deleted
287 symbol was marked external. */
288
289 if (1
290 && !S_IS_REGISTER (symbolP)
291 && (!S_GET_NAME (symbolP)
292 || S_IS_DEBUG (symbolP)
293 #ifdef TC_I960
294 /* FIXME-SOON this ifdef seems highly dubious to me. xoxorich. */
295 || !S_IS_DEFINED (symbolP)
296 || S_IS_EXTERNAL (symbolP)
297 #endif /* TC_I960 */
298 || (S_GET_NAME (symbolP)[0] != '\001'
299 && (flag_keep_locals || !S_LOCAL_NAME (symbolP)))))
300 {
301 symbolP->sy_number = symbol_number++;
302
303 /* The + 1 after strlen account for the \0 at the end of
304 each string. */
305 if (!S_IS_STABD (symbolP))
306 {
307 /* Ordinary case. */
308 symbolP->sy_name_offset = string_byte_count;
309 string_byte_count += strlen (S_GET_NAME (symbolP)) + 1;
310 }
311 else /* .Stabd case. */
312 symbolP->sy_name_offset = 0;
313 symbolPP = &(symbolP->sy_next);
314 }
315 else
316 {
317 if (S_IS_EXTERNAL (symbolP) || !S_IS_DEFINED (symbolP))
318 {
319 as_bad (_("Local symbol %s never defined"),
320 S_GET_NAME (symbolP));
321 } /* Oops. */
322
323 /* Unhook it from the chain. */
324 *symbolPP = symbol_next (symbolP);
325 } /* if this symbol should be in the output */
326 } /* for each symbol */
327
328 H_SET_SYMBOL_TABLE_SIZE (headers, symbol_number);
329 }
330
331 /* Find strings by crawling along symbol table chain. */
332
333 void
obj_emit_strings(where)334 obj_emit_strings (where)
335 char **where;
336 {
337 symbolS *symbolP;
338
339 #ifdef CROSS_COMPILE
340 /* Gotta do md_ byte-ordering stuff for string_byte_count first - KWK */
341 md_number_to_chars (*where, string_byte_count, sizeof (string_byte_count));
342 *where += sizeof (string_byte_count);
343 #else /* CROSS_COMPILE */
344 append (where, (char *) &string_byte_count,
345 (unsigned long) sizeof (string_byte_count));
346 #endif /* CROSS_COMPILE */
347
348 for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP))
349 {
350 if (S_GET_NAME (symbolP))
351 append (where, S_GET_NAME (symbolP),
352 (unsigned long) (strlen (S_GET_NAME (symbolP)) + 1));
353 } /* Walk symbol chain. */
354 }
355