1 /* 8 and 16 bit COFF relocation functions, for BFD.
2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 2000, 2001,
3 2002, 2003, 2004 Free Software Foundation, Inc.
4 Written by Cygnus Support.
5
6 This file is part of BFD, the Binary File Descriptor library.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
21
22 /* Most of this hacked by Steve Chamberlain <sac@cygnus.com>. */
23
24 /* These routines are used by coff-h8300 and coff-z8k to do
25 relocation.
26
27 FIXME: This code should be rewritten to support the new COFF
28 linker. Basically, they need to deal with COFF relocs rather than
29 BFD generic relocs. They should store the relocs in some location
30 where coff_link_input_bfd can find them (and coff_link_input_bfd
31 should be changed to use this location rather than rereading the
32 file) (unless info->keep_memory is FALSE, in which case they should
33 free up the relocs after dealing with them). */
34
35 #include "bfd.h"
36 #include "sysdep.h"
37 #include "libbfd.h"
38 #include "bfdlink.h"
39 #include "genlink.h"
40 #include "coff/internal.h"
41 #include "libcoff.h"
42
43 bfd_vma
bfd_coff_reloc16_get_value(reloc,link_info,input_section)44 bfd_coff_reloc16_get_value (reloc, link_info, input_section)
45 arelent *reloc;
46 struct bfd_link_info *link_info;
47 asection *input_section;
48 {
49 bfd_vma value;
50 asymbol *symbol = *(reloc->sym_ptr_ptr);
51 /* A symbol holds a pointer to a section, and an offset from the
52 base of the section. To relocate, we find where the section will
53 live in the output and add that in. */
54
55 if (bfd_is_und_section (symbol->section)
56 || bfd_is_com_section (symbol->section))
57 {
58 struct bfd_link_hash_entry *h;
59
60 /* The symbol is undefined in this BFD. Look it up in the
61 global linker hash table. FIXME: This should be changed when
62 we convert this stuff to use a specific final_link function
63 and change the interface to bfd_relax_section to not require
64 the generic symbols. */
65 h = bfd_wrapped_link_hash_lookup (input_section->owner, link_info,
66 bfd_asymbol_name (symbol),
67 FALSE, FALSE, TRUE);
68 if (h != (struct bfd_link_hash_entry *) NULL
69 && (h->type == bfd_link_hash_defined
70 || h->type == bfd_link_hash_defweak))
71 value = (h->u.def.value
72 + h->u.def.section->output_section->vma
73 + h->u.def.section->output_offset);
74 else if (h != (struct bfd_link_hash_entry *) NULL
75 && h->type == bfd_link_hash_common)
76 value = h->u.c.size;
77 else
78 {
79 if (!((*link_info->callbacks->undefined_symbol)
80 (link_info, bfd_asymbol_name (symbol),
81 input_section->owner, input_section, reloc->address,
82 TRUE)))
83 abort ();
84 value = 0;
85 }
86 }
87 else
88 {
89 value = symbol->value
90 + symbol->section->output_offset
91 + symbol->section->output_section->vma;
92 }
93
94 /* Add the value contained in the relocation. */
95 value += reloc->addend;
96
97 return value;
98 }
99
100 void
bfd_perform_slip(abfd,slip,input_section,value)101 bfd_perform_slip (abfd, slip, input_section, value)
102 bfd *abfd;
103 unsigned int slip;
104 asection *input_section;
105 bfd_vma value;
106 {
107 asymbol **s;
108
109 s = _bfd_generic_link_get_symbols (abfd);
110 BFD_ASSERT (s != (asymbol **) NULL);
111
112 /* Find all symbols past this point, and make them know
113 what's happened. */
114 while (*s)
115 {
116 asymbol *p = *s;
117 if (p->section == input_section)
118 {
119 /* This was pointing into this section, so mangle it. */
120 if (p->value > value)
121 {
122 p->value -= slip;
123 if (p->udata.p != NULL)
124 {
125 struct generic_link_hash_entry *h;
126
127 h = (struct generic_link_hash_entry *) p->udata.p;
128 BFD_ASSERT (h->root.type == bfd_link_hash_defined
129 || h->root.type == bfd_link_hash_defweak);
130 h->root.u.def.value -= slip;
131 BFD_ASSERT (h->root.u.def.value == p->value);
132 }
133 }
134 }
135 s++;
136 }
137 }
138
139 bfd_boolean
bfd_coff_reloc16_relax_section(abfd,input_section,link_info,again)140 bfd_coff_reloc16_relax_section (abfd, input_section, link_info, again)
141 bfd *abfd;
142 asection *input_section;
143 struct bfd_link_info *link_info;
144 bfd_boolean *again;
145 {
146 /* Get enough memory to hold the stuff. */
147 bfd *input_bfd = input_section->owner;
148 unsigned *shrinks;
149 unsigned shrink = 0;
150 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
151 arelent **reloc_vector = NULL;
152 long reloc_count;
153
154 /* We only do global relaxation once. It is not safe to do it multiple
155 times (see discussion of the "shrinks" array below). */
156 *again = FALSE;
157
158 if (reloc_size < 0)
159 return FALSE;
160
161 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
162 if (!reloc_vector && reloc_size > 0)
163 return FALSE;
164
165 /* Get the relocs and think about them. */
166 reloc_count =
167 bfd_canonicalize_reloc (input_bfd, input_section, reloc_vector,
168 _bfd_generic_link_get_symbols (input_bfd));
169 if (reloc_count < 0)
170 {
171 free (reloc_vector);
172 return FALSE;
173 }
174
175 /* The reloc16.c and related relaxing code is very simple, the price
176 for that simplicity is we can only call this function once for
177 each section.
178
179 So, to get the best results within that limitation, we do multiple
180 relaxing passes over each section here. That involves keeping track
181 of the "shrink" at each reloc in the section. This allows us to
182 accurately determine the relative location of two relocs within
183 this section.
184
185 In theory, if we kept the "shrinks" array for each section for the
186 entire link, we could use the generic relaxing code in the linker
187 and get better results, particularly for jsr->bsr and 24->16 bit
188 memory reference relaxations. */
189
190 if (reloc_count > 0)
191 {
192 int another_pass = 0;
193 bfd_size_type amt;
194
195 /* Allocate and initialize the shrinks array for this section.
196 The last element is used as an accumulator of shrinks. */
197 amt = reloc_count + 1;
198 amt *= sizeof (unsigned);
199 shrinks = (unsigned *) bfd_zmalloc (amt);
200
201 /* Loop until nothing changes in this section. */
202 do
203 {
204 arelent **parent;
205 unsigned int i;
206 long j;
207
208 another_pass = 0;
209
210 for (i = 0, parent = reloc_vector; *parent; parent++, i++)
211 {
212 /* Let the target/machine dependent code examine each reloc
213 in this section and attempt to shrink it. */
214 shrink = bfd_coff_reloc16_estimate (abfd, input_section, *parent,
215 shrinks[i], link_info);
216
217 /* If it shrunk, note it in the shrinks array and set up for
218 another pass. */
219 if (shrink != shrinks[i])
220 {
221 another_pass = 1;
222 for (j = i + 1; j <= reloc_count; j++)
223 shrinks[j] += shrink - shrinks[i];
224 }
225 }
226 }
227 while (another_pass);
228
229 shrink = shrinks[reloc_count];
230 free ((char *) shrinks);
231 }
232
233 input_section->rawsize = input_section->size;
234 input_section->size -= shrink;
235 free ((char *) reloc_vector);
236 return TRUE;
237 }
238
239 bfd_byte *
bfd_coff_reloc16_get_relocated_section_contents(in_abfd,link_info,link_order,data,relocatable,symbols)240 bfd_coff_reloc16_get_relocated_section_contents (in_abfd,
241 link_info,
242 link_order,
243 data,
244 relocatable,
245 symbols)
246 bfd *in_abfd;
247 struct bfd_link_info *link_info;
248 struct bfd_link_order *link_order;
249 bfd_byte *data;
250 bfd_boolean relocatable;
251 asymbol **symbols;
252 {
253 /* Get enough memory to hold the stuff. */
254 bfd *input_bfd = link_order->u.indirect.section->owner;
255 asection *input_section = link_order->u.indirect.section;
256 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
257 arelent **reloc_vector;
258 long reloc_count;
259 bfd_size_type sz;
260
261 if (reloc_size < 0)
262 return NULL;
263
264 /* If producing relocatable output, don't bother to relax. */
265 if (relocatable)
266 return bfd_generic_get_relocated_section_contents (in_abfd, link_info,
267 link_order,
268 data, relocatable,
269 symbols);
270
271 /* Read in the section. */
272 sz = input_section->rawsize ? input_section->rawsize : input_section->size;
273 if (!bfd_get_section_contents (input_bfd, input_section, data, 0, sz))
274 return NULL;
275
276 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
277 if (!reloc_vector && reloc_size != 0)
278 return NULL;
279
280 reloc_count = bfd_canonicalize_reloc (input_bfd,
281 input_section,
282 reloc_vector,
283 symbols);
284 if (reloc_count < 0)
285 {
286 free (reloc_vector);
287 return NULL;
288 }
289
290 if (reloc_count > 0)
291 {
292 arelent **parent = reloc_vector;
293 arelent *reloc;
294 unsigned int dst_address = 0;
295 unsigned int src_address = 0;
296 unsigned int run;
297 unsigned int idx;
298
299 /* Find how long a run we can do. */
300 while (dst_address < link_order->size)
301 {
302 reloc = *parent;
303 if (reloc)
304 {
305 /* Note that the relaxing didn't tie up the addresses in the
306 relocation, so we use the original address to work out the
307 run of non-relocated data. */
308 run = reloc->address - src_address;
309 parent++;
310 }
311 else
312 {
313 run = link_order->size - dst_address;
314 }
315
316 /* Copy the bytes. */
317 for (idx = 0; idx < run; idx++)
318 data[dst_address++] = data[src_address++];
319
320 /* Now do the relocation. */
321 if (reloc)
322 {
323 bfd_coff_reloc16_extra_cases (input_bfd, link_info, link_order,
324 reloc, data, &src_address,
325 &dst_address);
326 }
327 }
328 }
329 free ((char *) reloc_vector);
330 return data;
331 }
332