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[binutils.git] / bfd / reloc16.c
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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 Free Software Foundation, Inc.
4 Written by Cygnus Support.
6 This file is part of BFD, the Binary File Descriptor library.
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.
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.
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 /* Most of this hacked by Steve Chamberlain <sac@cygnus.com>. */
24 /* These routines are used by coff-h8300 and coff-z8k to do
25 relocation.
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). */
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"
43 bfd_vma
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;
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. */
55 if (bfd_is_und_section (symbol->section)
56 || bfd_is_com_section (symbol->section))
58 struct bfd_link_hash_entry *h;
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
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;
87 else
89 value = symbol->value
90 + symbol->section->output_offset
91 + symbol->section->output_section->vma;
94 /* Add the value contained in the relocation. */
95 value += reloc->addend;
97 return value;
100 void
101 bfd_perform_slip (abfd, slip, input_section, value)
102 bfd *abfd;
103 unsigned int slip;
104 asection *input_section;
105 bfd_vma value;
107 asymbol **s;
109 s = _bfd_generic_link_get_symbols (abfd);
110 BFD_ASSERT (s != (asymbol **) NULL);
112 /* Find all symbols past this point, and make them know
113 what's happened. */
114 while (*s)
116 asymbol *p = *s;
117 if (p->section == input_section)
119 /* This was pointing into this section, so mangle it. */
120 if (p->value > value)
122 p->value -= slip;
123 if (p->udata.p != NULL)
125 struct generic_link_hash_entry *h;
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);
135 s++;
139 bfd_boolean
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;
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;
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;
158 if (reloc_size < 0)
159 return FALSE;
161 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
162 if (!reloc_vector && reloc_size > 0)
163 return FALSE;
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)
171 free (reloc_vector);
172 return FALSE;
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.
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.
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. */
190 if (reloc_count > 0)
192 int another_pass = 0;
193 bfd_size_type amt;
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);
201 /* Loop until nothing changes in this section. */
204 arelent **parent;
205 unsigned int i;
206 long j;
208 another_pass = 0;
210 for (i = 0, parent = reloc_vector; *parent; parent++, i++)
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);
217 /* If it shrunk, note it in the shrinks array and set up for
218 another pass. */
219 if (shrink != shrinks[i])
221 another_pass = 1;
222 for (j = i + 1; j <= reloc_count; j++)
223 shrinks[j] += shrink - shrinks[i];
227 while (another_pass);
229 shrink = shrinks[reloc_count];
230 free ((char *) shrinks);
233 input_section->_cooked_size -= shrink;
234 free ((char *) reloc_vector);
235 return TRUE;
238 bfd_byte *
239 bfd_coff_reloc16_get_relocated_section_contents (in_abfd,
240 link_info,
241 link_order,
242 data,
243 relocatable,
244 symbols)
245 bfd *in_abfd;
246 struct bfd_link_info *link_info;
247 struct bfd_link_order *link_order;
248 bfd_byte *data;
249 bfd_boolean relocatable;
250 asymbol **symbols;
252 /* Get enough memory to hold the stuff. */
253 bfd *input_bfd = link_order->u.indirect.section->owner;
254 asection *input_section = link_order->u.indirect.section;
255 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
256 arelent **reloc_vector;
257 long reloc_count;
259 if (reloc_size < 0)
260 return NULL;
262 /* If producing relocatable output, don't bother to relax. */
263 if (relocatable)
264 return bfd_generic_get_relocated_section_contents (in_abfd, link_info,
265 link_order,
266 data, relocatable,
267 symbols);
269 /* Read in the section. */
270 if (!bfd_get_section_contents (input_bfd,
271 input_section,
272 data,
273 (bfd_vma) 0,
274 input_section->_raw_size))
275 return NULL;
277 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
278 if (!reloc_vector && reloc_size != 0)
279 return NULL;
281 reloc_count = bfd_canonicalize_reloc (input_bfd,
282 input_section,
283 reloc_vector,
284 symbols);
285 if (reloc_count < 0)
287 free (reloc_vector);
288 return NULL;
291 if (reloc_count > 0)
293 arelent **parent = reloc_vector;
294 arelent *reloc;
295 unsigned int dst_address = 0;
296 unsigned int src_address = 0;
297 unsigned int run;
298 unsigned int idx;
300 /* Find how long a run we can do. */
301 while (dst_address < link_order->size)
303 reloc = *parent;
304 if (reloc)
306 /* Note that the relaxing didn't tie up the addresses in the
307 relocation, so we use the original address to work out the
308 run of non-relocated data. */
309 run = reloc->address - src_address;
310 parent++;
312 else
314 run = link_order->size - dst_address;
317 /* Copy the bytes. */
318 for (idx = 0; idx < run; idx++)
319 data[dst_address++] = data[src_address++];
321 /* Now do the relocation. */
322 if (reloc)
324 bfd_coff_reloc16_extra_cases (input_bfd, link_info, link_order,
325 reloc, data, &src_address,
326 &dst_address);
330 free ((char *) reloc_vector);
331 return data;