1 /* b.out object file format
2 Copyright (C) 1989, 1990, 1991 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
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 2,
9 or (at your option) any later version.
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.
16 You should have received a copy of the GNU General Public
17 License along with GAS; see the file COPYING. If not, write
18 to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
25 const short /* in: segT out: N_TYPE bits */
35 N_UNDF
, /* bignum/flonum */
36 N_UNDF
, /* difference */
37 N_REGISTER
, /* register */
40 const segT N_TYPE_seg
[N_TYPE
+2] = { /* 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 */
59 static void obj_bout_stab(int what
);
60 static void obj_bout_line(void);
61 static void obj_bout_desc(void);
63 static void obj_bout_desc();
64 static void obj_bout_stab();
65 static void obj_bout_line();
68 const pseudo_typeS obj_pseudo_table
[] = {
69 /* stabs (aka a.out aka b.out directives for debug symbols) */
70 { "desc", obj_bout_desc
, 0 }, /* def */
71 { "line", obj_bout_line
, 0 }, /* source code line number */
72 { "stabd", obj_bout_stab
, 'd' }, /* stabs */
73 { "stabn", obj_bout_stab
, 'n' }, /* stabs */
74 { "stabs", obj_bout_stab
, 's' }, /* stabs */
76 /* coff debugging directives. Currently ignored silently */
77 { "def", s_ignore
, 0 },
78 { "dim", s_ignore
, 0 },
79 { "endef", s_ignore
, 0 },
80 { "ln", s_ignore
, 0 },
81 { "scl", s_ignore
, 0 },
82 { "size", s_ignore
, 0 },
83 { "tag", s_ignore
, 0 },
84 { "type", s_ignore
, 0 },
85 { "val", s_ignore
, 0 },
87 /* other stuff we don't handle */
88 { "ABORT", s_ignore
, 0 },
89 { "ident", s_ignore
, 0 },
91 { NULL
} /* end sentinel */
92 }; /* obj_pseudo_table */
99 * Crawl along a fixS chain. Emit the segment's relocations.
101 void obj_emit_relocations(where
, fixP
, segment_address_in_file
)
103 fixS
*fixP
; /* Fixup chain for this segment. */
104 relax_addressT segment_address_in_file
;
106 for (; fixP
; fixP
= fixP
->fx_next
) {
107 if (fixP
->fx_addsy
!= NULL
) {
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 */
118 void obj_header_append(where
, headers
)
120 object_headers
*headers
;
122 /* Always leave in host byte order */
124 headers
->header
.a_talign
= section_alignment
[SEG_TEXT
];
126 if (headers
->header
.a_talign
< 2){
127 headers
->header
.a_talign
= 2;
128 } /* force to at least 2 */
130 headers
->header
.a_dalign
= section_alignment
[SEG_DATA
];
131 headers
->header
.a_balign
= section_alignment
[SEG_BSS
];
133 headers
->header
.a_tload
= 0;
134 headers
->header
.a_dload
= md_section_align(SEG_DATA
, H_GET_TEXT_SIZE(headers
));
136 append(where
, (char *) &headers
->header
, sizeof(headers
->header
));
137 } /* a_header_append() */
139 void obj_symbol_to_chars(where
, symbolP
)
143 /* leave in host byte order */
144 append(where
, (char *)&symbolP
->sy_symbol
, sizeof(obj_symbol_type
));
145 } /* obj_symbol_to_chars() */
147 void obj_emit_symbols(where
, symbol_rootP
)
149 symbolS
*symbol_rootP
;
154 * Emit all symbols left in the symbol chain.
156 for(symbolP
= symbol_rootP
; symbolP
; symbolP
= symbol_next(symbolP
)) {
157 /* Used to save the offset of the name. It is used to point
158 to the string in memory but must be a file offset. */
161 temp
= S_GET_NAME(symbolP
);
162 S_SET_OFFSET(symbolP
, symbolP
->sy_name_offset
);
164 /* Any symbol still undefined and is not a dbg symbol is made N_EXT. */
165 if (!S_IS_DEBUG(symbolP
) && !S_IS_DEFINED(symbolP
)) S_SET_EXTERNAL(symbolP
);
167 obj_symbol_to_chars(where
, symbolP
);
168 S_SET_NAME(symbolP
,temp
);
170 } /* emit_symbols() */
172 void obj_symbol_new_hook(symbolP
)
175 S_SET_OTHER(symbolP
, 0);
176 S_SET_DESC(symbolP
, 0);
178 } /* obj_symbol_new_hook() */
180 static void obj_bout_line() {
181 /* Assume delimiter is part of expression. */
182 /* BSD4.2 as fails with delightful bug, so we */
183 /* are not being incompatible here. */
184 new_logical_line ((char *)NULL
, (int)(get_absolute_expression ()));
185 demand_empty_rest_of_line();
186 } /* obj_bout_line() */
191 * Handle .stabX directives, which used to be open-coded.
192 * So much creeping featurism overloaded the semantics that we decided
193 * to put all .stabX thinking in one place. Here.
195 * We try to make any .stabX directive legal. Other people's AS will often
196 * do assembly-time consistency checks: eg assigning meaning to n_type bits
197 * and "protecting" you from setting them to certain values. (They also zero
198 * certain bits before emitting symbols. Tut tut.)
200 * If an expression is not absolute we either gripe or use the relocation
201 * information. Other people's assemblers silently forget information they
202 * don't need and invent information they need that you didn't supply.
204 * .stabX directives always make a symbol table entry. It may be junk if
205 * the rest of your .stabX directive is malformed.
207 static void obj_bout_stab(what
)
210 register symbolS
* symbolP
= 0;
211 register char * string
;
214 int goof
; /* TRUE if we have aborted. */
218 * Enter with input_line_pointer pointing past .stabX and any following
221 goof
= 0; /* JF who forgot this?? */
223 string
= demand_copy_C_string(& length
);
225 if (*input_line_pointer
== ',')
226 input_line_pointer
++;
228 as_bad("I need a comma after symbol's name");
235 * Input_line_pointer->after ','. String->symbol name.
238 symbolP
= symbol_new(string
,
244 S_SET_NAME(symbolP
,NULL
); /* .stabd feature. */
245 S_SET_VALUE(symbolP
,obstack_next_free(&frags
) -
246 frag_now
->fr_literal
);
247 symbolP
->sy_frag
= frag_now
;
251 symbolP
->sy_frag
= &zero_address_frag
;
255 symbolP
->sy_frag
= & zero_address_frag
;
262 if (get_absolute_expression_and_terminator(& longint
) == ',')
263 symbolP
->sy_symbol
.n_type
= saved_type
= longint
;
265 as_bad("I want a comma after the n_type expression");
267 input_line_pointer
--; /* Backup over a non-',' char. */
271 if (get_absolute_expression_and_terminator (& longint
) == ',')
272 S_SET_OTHER(symbolP
,longint
);
274 as_bad("I want a comma after the n_other expression");
276 input_line_pointer
--; /* Backup over a non-',' char. */
280 S_SET_DESC(symbolP
, get_absolute_expression ());
281 if (what
== 's' || what
== 'n') {
282 if (* input_line_pointer
!= ',') {
283 as_bad("I want a comma after the n_desc expression");
286 input_line_pointer
++;
290 if ((! goof
) && (what
=='s' || what
=='n')) {
292 symbolP
->sy_symbol
.n_type
= saved_type
;
295 ignore_rest_of_line ();
297 demand_empty_rest_of_line ();
298 } /* obj_bout_stab() */
300 static void obj_bout_desc() {
304 register symbolS
* symbolP
;
308 * Frob invented at RMS' request. Set the n_desc of a symbol.
310 name
= input_line_pointer
;
311 c
= get_symbol_end();
312 p
= input_line_pointer
;
315 if (*input_line_pointer
!= ',') {
317 as_bad("Expected comma after name \"%s\"", name
);
319 ignore_rest_of_line();
321 input_line_pointer
++;
322 temp
= get_absolute_expression ();
324 symbolP
= symbol_find_or_make(name
);
326 S_SET_DESC(symbolP
,temp
);
328 demand_empty_rest_of_line();
329 } /* obj_bout_desc() */
331 void obj_read_begin_hook() {
333 } /* obj_read_begin_hook() */
335 void obj_crawl_symbol_chain(headers
)
336 object_headers
*headers
;
340 int symbol_number
= 0;
342 /* JF deal with forward references first... */
343 for (symbolP
= symbol_rootP
; symbolP
; symbolP
= symbol_next(symbolP
)) {
344 if (symbolP
->sy_forward
) {
345 S_SET_VALUE(symbolP
, S_GET_VALUE(symbolP
)
346 + S_GET_VALUE(symbolP
->sy_forward
)
347 + symbolP
->sy_forward
->sy_frag
->fr_address
);
349 symbolP
->sy_forward
=0;
350 } /* if it has a forward reference */
351 } /* walk the symbol chain */
353 tc_crawl_symbol_chain(headers
);
355 symbolPP
= & symbol_rootP
; /*->last symbol chain link. */
356 while ((symbolP
= *symbolPP
) != NULL
) {
357 if (flagseen
['R'] && (S_GET_SEGMENT(symbolP
) == SEG_DATA
)) {
358 S_SET_SEGMENT(symbolP
, SEG_TEXT
);
359 } /* if pusing data into text */
361 S_SET_VALUE(symbolP
, S_GET_VALUE(symbolP
) + symbolP
->sy_frag
->fr_address
);
363 /* OK, here is how we decide which symbols go out into the
364 brave new symtab. Symbols that do are:
366 * symbols with no name (stabd's?)
367 * symbols with debug info in their N_TYPE
369 Symbols that don't are:
370 * symbols that are registers
371 * symbols with \1 as their 3rd character (numeric labels)
372 * "local labels" as defined by S_LOCAL_NAME(name)
373 if the -L switch was passed to gas.
375 All other symbols are output. We complain if a deleted
376 symbol was marked external. */
380 && !S_IS_REGISTER(symbolP
)
381 && (!S_GET_NAME(symbolP
)
382 || S_IS_DEBUG(symbolP
)
384 /* FIXME-SOON this ifdef seems highly dubious to me. xoxorich. */
385 || !S_IS_DEFINED(symbolP
)
386 || S_IS_EXTERNAL(symbolP
)
388 || (S_GET_NAME(symbolP
)[0] != '\001' && (flagseen
['L'] || ! S_LOCAL_NAME(symbolP
))))) {
389 symbolP
->sy_number
= symbol_number
++;
391 /* The + 1 after strlen account for the \0 at the
392 end of each string */
393 if (!S_IS_STABD(symbolP
)) {
395 symbolP
->sy_name_offset
= string_byte_count
;
396 string_byte_count
+= strlen(S_GET_NAME(symbolP
)) + 1;
398 else /* .Stabd case. */
399 symbolP
->sy_name_offset
= 0;
400 symbolPP
= &(symbol_next(symbolP
));
402 if (S_IS_EXTERNAL(symbolP
) || !S_IS_DEFINED(symbolP
)) {
403 as_bad("Local symbol %s never defined", S_GET_NAME(symbolP
));
406 /* Unhook it from the chain */
407 *symbolPP
= symbol_next(symbolP
);
408 } /* if this symbol should be in the output */
409 } /* for each symbol */
411 H_SET_SYMBOL_TABLE_SIZE(headers
, symbol_number
);
414 } /* obj_crawl_symbol_chain() */
417 * Find strings by crawling along symbol table chain.
420 void obj_emit_strings(where
)
426 /* Gotta do md_ byte-ordering stuff for string_byte_count first - KWK */
427 md_number_to_chars(*where
, string_byte_count
, sizeof(string_byte_count
));
428 *where
+= sizeof(string_byte_count
);
429 #else /* CROSS_COMPILE */
430 append(where
, (char *) &string_byte_count
, (unsigned long) sizeof(string_byte_count
));
431 #endif /* CROSS_COMPILE */
433 for(symbolP
= symbol_rootP
; symbolP
; symbolP
= symbol_next(symbolP
)) {
434 if(S_GET_NAME(symbolP
))
435 append(where
, S_GET_NAME(symbolP
), (unsigned long)(strlen (S_GET_NAME(symbolP
)) + 1));
436 } /* walk symbol chain */
439 } /* obj_emit_strings() */
448 /* end of obj-bout.c */