1 /* All symbol handling for the linker
2 Copyright (C) 1991 Free Software Foundation, Inc.
3 Written by Steve Chamberlain steve@cygnus.com
5 This file is part of GLD, the Gnu Linker.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
22 We keep a hash table of global symbols. Each entry in a hash table
23 is called an ldsym_type. Each has three chains; a pointer to a
24 chain of definitions for the symbol (hopefully one long), a pointer
25 to a chain of references to the symbol, and a pointer to a chain of
26 common symbols. Each pointer points into the canonical symbol table
27 provided by bfd, each one of which points to an asymbol. During
28 linkage, the linker uses the udata field to point to the next entry
29 in a canonical table....
34 +----------+ +----------+
35 | defs | a canonical symbol table
36 +----------+ +----------+
37 | refs | -----> | one entry| -----> asymbol
38 +----------+ +----------+ | |
39 | coms | | | +---------+
40 +----------+ +----------+ | udata |-----> another canonical symbol
45 It is very simple to make all the symbol pointers point to the same
46 definition - just run down the chain and make the asymbols pointers
47 within the canonical table point to the asymbol attacthed to the
48 definition of the symbol.
61 extern bfd
*output_bfd
;
62 extern strip_symbols_type strip_symbols
;
63 extern discard_locals_type discard_locals
;
64 /* Head and tail of global symbol table chronological list */
66 ldsym_type
*symbol_head
= (ldsym_type
*)NULL
;
67 ldsym_type
**symbol_tail_ptr
= &symbol_head
;
69 extern ld_config_type config
;
71 struct obstack global_sym_obstack
;
72 #define obstack_chunk_alloc ldmalloc
73 #define obstack_chunk_free free
76 incremented for each symbol in the ldsym_type table
77 no matter what flavour it is
79 unsigned int global_symbol_count
;
83 extern boolean option_longmap
;
87 static ldsym_type
*global_symbol_hash_table
[TABSIZE
];
89 /* Compute the hash code for symbol name KEY. */
96 DEFUN(hash_string
,(key
),
99 register CONST
char *cp
;
105 k
= (((k
<< 1) + (k
>> 14)) ^ (*cp
++)) & 0x3fff;
113 #endif ldsym_type *bp;
115 DEFUN(search
,(key
,hashval
) ,
120 for (bp
= global_symbol_hash_table
[hashval
]; bp
; bp
= bp
->link
)
121 if (! strcmp (key
, bp
->name
)) {
122 if (bp
->flags
& SYM_INDIRECT
) {
123 /* Use the symbol we're aliased to instead */
124 return (ldsym_type
*)(bp
->sdefs_chain
);
132 /* Get the symbol table entry for the global symbol named KEY.
133 Create one if there is none. */
135 DEFUN(ldsym_get
,(key
),
138 register int hashval
;
139 register ldsym_type
*bp
;
141 /* Determine the proper bucket. */
143 hashval
= hash_string (key
) % TABSIZE
;
145 /* Search the bucket. */
146 bp
= search(key
, hashval
);
151 /* Nothing was found; create a new symbol table entry. */
153 bp
= (ldsym_type
*) obstack_alloc (&global_sym_obstack
, (bfd_size_type
)(sizeof (ldsym_type
)));
154 bp
->srefs_chain
= (asymbol
**)NULL
;
155 bp
->sdefs_chain
= (asymbol
**)NULL
;
156 bp
->scoms_chain
= (asymbol
**)NULL
;
157 bp
->name
= obstack_copy(&global_sym_obstack
, key
, strlen(key
)+1);
159 /* Add the entry to the bucket. */
161 bp
->link
= global_symbol_hash_table
[hashval
];
162 global_symbol_hash_table
[hashval
] = bp
;
164 /* Keep the chronological list up to date too */
165 *symbol_tail_ptr
= bp
;
166 symbol_tail_ptr
= &bp
->next
;
168 global_symbol_count
++;
173 /* Like `ldsym_get' but return 0 if the symbol is not already known. */
176 DEFUN(ldsym_get_soft
,(key
),
179 register int hashval
;
180 /* Determine which bucket. */
182 hashval
= hash_string (key
) % TABSIZE
;
184 /* Search the bucket. */
185 return search(key
, hashval
);
193 list_file_locals (entry
)
194 lang_input_statement_type
*entry
;
197 fprintf (config
.map_file
, "\nLocal symbols of ");
199 fprintf (config
.map_file
, ":\n\n");
200 if (entry
->asymbols
) {
201 for (q
= entry
->asymbols
; *q
; q
++)
204 /* If this is a definition,
205 update it if necessary by this file's start address. */
206 if (p
->flags
& BSF_LOCAL
)
207 info(" %V %s\n",p
->value
, p
->name
);
214 DEFUN(print_file_stuff
,(f
),
215 lang_input_statement_type
*f
)
217 fprintf (config
.map_file
," %s\n", f
->filename
);
218 if (f
->just_syms_flag
)
220 fprintf (config
.map_file
, " symbols only\n");
225 if (true || option_longmap
) {
226 for (s
= f
->the_bfd
->sections
;
227 s
!= (asection
*)NULL
;
229 print_address(s
->output_offset
);
232 fprintf (config
.map_file
, " %08x 2**%2ud %s\n",
233 (unsigned)bfd_get_section_size_after_reloc(s
),
234 s
->alignment_power
, s
->name
);
239 fprintf (config
.map_file
, " %08x 2**%2ud %s\n",
240 (unsigned)bfd_get_section_size_before_reloc(s
),
241 s
->alignment_power
, s
->name
);
247 for (s
= f
->the_bfd
->sections
;
248 s
!= (asection
*)NULL
;
250 fprintf(config
.map_file
, "%s ", s
->name
);
251 print_address(s
->output_offset
);
252 fprintf(config
.map_file
, "(%x)", (unsigned)bfd_get_section_size_after_reloc(s
));
254 fprintf(config
.map_file
, "hex \n");
257 fprintf (config
.map_file
, "\n");
261 ldsym_print_symbol_table ()
263 fprintf (config
.map_file
, "**FILES**\n\n");
265 lang_for_each_file(print_file_stuff
);
267 fprintf(config
.map_file
, "**GLOBAL SYMBOLS**\n\n");
268 fprintf(config
.map_file
, "offset section offset symbol\n");
270 register ldsym_type
*sp
;
272 for (sp
= symbol_head
; sp
; sp
= sp
->next
)
274 if (sp
->flags
& SYM_INDIRECT
) {
275 fprintf(config
.map_file
,"indirect %s to %s\n",
276 sp
->name
, (((ldsym_type
*)(sp
->sdefs_chain
))->name
));
281 asymbol
*defsym
= *(sp
->sdefs_chain
);
282 asection
*defsec
= bfd_get_section(defsym
);
283 print_address(defsym
->value
);
286 fprintf(config
.map_file
, " %-10s",
287 bfd_section_name(output_bfd
,
290 print_address(defsym
->value
+defsec
->vma
);
295 fprintf(config
.map_file
, " .......");
301 if (sp
->scoms_chain
) {
302 fprintf(config
.map_file
, "common ");
303 print_address((*(sp
->scoms_chain
))->value
);
304 fprintf(config
.map_file
, " %s ",sp
->name
);
306 else if (sp
->sdefs_chain
) {
307 fprintf(config
.map_file
, " %s ",sp
->name
);
310 fprintf(config
.map_file
, "undefined ");
311 fprintf(config
.map_file
, "%s ",sp
->name
);
319 if (option_longmap
) {
320 lang_for_each_file(list_file_locals
);
324 extern lang_output_section_statement_type
*create_object_symbols
;
327 write_file_locals(output_buffer
)
328 asymbol
**output_buffer
;
330 LANG_FOR_EACH_INPUT_STATEMENT(entry
)
332 /* Run trough the symbols and work out what to do with them */
335 /* Add one for the filename symbol if needed */
336 if (create_object_symbols
337 != (lang_output_section_statement_type
*)NULL
) {
339 for (s
= entry
->the_bfd
->sections
;
340 s
!= (asection
*)NULL
;
342 if (s
->output_section
== create_object_symbols
->bfd_section
) {
343 /* Add symbol to this section */
345 (asymbol
*)bfd_make_empty_symbol(entry
->the_bfd
);
346 newsym
->name
= entry
->local_sym_name
;
347 /* The symbol belongs to the output file's text section */
349 /* The value is the start of this section in the output file*/
351 newsym
->flags
= BSF_LOCAL
;
353 *output_buffer
++ = newsym
;
358 for (i
= 0; i
< entry
->symbol_count
; i
++)
360 asymbol
*p
= entry
->asymbols
[i
];
361 /* FIXME, temporary hack, since not all of ld knows about the new abs section convention */
364 p
->section
= &bfd_abs_section
;
365 if (flag_is_global(p
->flags
) )
367 /* We are only interested in outputting
368 globals at this stage in special circumstances */
369 if (p
->the_bfd
== entry
->the_bfd
370 && flag_is_not_at_end(p
->flags
)) {
371 /* And this is one of them */
372 *(output_buffer
++) = p
;
373 p
->flags
|= BSF_KEEP
;
377 if (flag_is_debugger(p
->flags
))
379 /* Only keep the debugger symbols if no stripping required */
380 if (strip_symbols
== STRIP_NONE
) {
381 *output_buffer
++ = p
;
384 else if (p
->section
== &bfd_und_section
385 || p
->section
== &bfd_com_section
)
387 /* These must be global. */
389 else if (flag_is_ordinary_local(p
->flags
))
391 if (discard_locals
== DISCARD_ALL
)
393 else if (discard_locals
== DISCARD_L
&&
394 (p
->name
[0] == lprefix
))
396 else if (p
->flags
== BSF_WARNING
)
399 { *output_buffer
++ = p
; }
401 else if (p
->flags
& BSF_CTOR
) {
413 return output_buffer
;
418 write_file_globals(symbol_table
)
419 asymbol
**symbol_table
;
423 if ((sp
->flags
& SYM_INDIRECT
) == 0 && sp
->sdefs_chain
!= (asymbol
**)NULL
) {
424 asymbol
*bufp
= (*(sp
->sdefs_chain
));
426 if ((bufp
->flags
& BSF_KEEP
) ==0) {
427 ASSERT(bufp
!= (asymbol
*)NULL
);
429 bufp
->name
= sp
->name
;
431 if (sp
->scoms_chain
!= (asymbol
**)NULL
)
435 defined as common but not allocated, this happens
436 only with -r and not -d, write out a common
439 bufp
= *(sp
->scoms_chain
);
441 *symbol_table
++ = bufp
;
444 else if (sp
->scoms_chain
!= (asymbol
**)NULL
) {
445 /* This symbol is a common - just output */
446 asymbol
*bufp
= (*(sp
->scoms_chain
));
447 *symbol_table
++ = bufp
;
449 else if (sp
->srefs_chain
!= (asymbol
**)NULL
) {
450 /* This symbol is undefined but has a reference */
451 asymbol
*bufp
= (*(sp
->srefs_chain
));
452 *symbol_table
++ = bufp
;
456 This symbol has neither defs nor refs, it must have come
457 from the command line, since noone has used it it has no
458 data attatched, so we'll ignore it
470 if (strip_symbols
!= STRIP_ALL
) {
471 /* We know the maximum size of the symbol table -
472 it's the size of all the global symbols ever seen +
473 the size of all the symbols from all the files +
474 the number of files (for the per file symbols)
475 +1 (for the null at the end)
477 extern unsigned int total_files_seen
;
478 extern unsigned int total_symbols_seen
;
480 asymbol
** symbol_table
= (asymbol
**)
481 ldmalloc ((bfd_size_type
)(global_symbol_count
+
483 total_symbols_seen
+ 1) * sizeof (asymbol
*));
484 asymbol
** tablep
= write_file_locals(symbol_table
);
486 tablep
= write_file_globals(tablep
);
488 *tablep
= (asymbol
*)NULL
;
489 bfd_set_symtab(output_bfd
, symbol_table
, (unsigned)( tablep
- symbol_table
));
494 return true if the supplied symbol name is not in the
498 DEFUN(ldsym_undefined
,(sym
),
501 ldsym_type
*from_table
= ldsym_get_soft(sym
);
502 if (from_table
!= (ldsym_type
*)NULL
)
504 if (from_table
->sdefs_chain
!= (asymbol
**)NULL
) return false;
510 DEFUN_VOID(ldsym_init
)
512 obstack_begin(&global_sym_obstack
, 20000);