bfd/
[binutils.git] / bfd / reloc16.c
blob768b288d824fd489e8e58a39c7a2673a3b11941e
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, 2005, 2007, 2008, 2009 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 3 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., 51 Franklin Street - Fifth Floor, Boston,
21 MA 02110-1301, USA. */
24 /* Most of this hacked by Steve Chamberlain <sac@cygnus.com>. */
26 /* These routines are used by coff-h8300 and coff-z8k to do
27 relocation.
29 FIXME: This code should be rewritten to support the new COFF
30 linker. Basically, they need to deal with COFF relocs rather than
31 BFD generic relocs. They should store the relocs in some location
32 where coff_link_input_bfd can find them (and coff_link_input_bfd
33 should be changed to use this location rather than rereading the
34 file) (unless info->keep_memory is FALSE, in which case they should
35 free up the relocs after dealing with them). */
37 #include "sysdep.h"
38 #include "bfd.h"
39 #include "libbfd.h"
40 #include "bfdlink.h"
41 #include "genlink.h"
42 #include "coff/internal.h"
43 #include "libcoff.h"
45 bfd_vma
46 bfd_coff_reloc16_get_value (reloc, link_info, input_section)
47 arelent *reloc;
48 struct bfd_link_info *link_info;
49 asection *input_section;
51 bfd_vma value;
52 asymbol *symbol = *(reloc->sym_ptr_ptr);
53 /* A symbol holds a pointer to a section, and an offset from the
54 base of the section. To relocate, we find where the section will
55 live in the output and add that in. */
57 if (bfd_is_und_section (symbol->section)
58 || bfd_is_com_section (symbol->section))
60 struct bfd_link_hash_entry *h;
62 /* The symbol is undefined in this BFD. Look it up in the
63 global linker hash table. FIXME: This should be changed when
64 we convert this stuff to use a specific final_link function
65 and change the interface to bfd_relax_section to not require
66 the generic symbols. */
67 h = bfd_wrapped_link_hash_lookup (input_section->owner, link_info,
68 bfd_asymbol_name (symbol),
69 FALSE, FALSE, TRUE);
70 if (h != (struct bfd_link_hash_entry *) NULL
71 && (h->type == bfd_link_hash_defined
72 || h->type == bfd_link_hash_defweak))
73 value = (h->u.def.value
74 + h->u.def.section->output_section->vma
75 + h->u.def.section->output_offset);
76 else if (h != (struct bfd_link_hash_entry *) NULL
77 && h->type == bfd_link_hash_common)
78 value = h->u.c.size;
79 else if (h != (struct bfd_link_hash_entry *) NULL
80 && h->type == bfd_link_hash_undefweak)
81 /* This is a GNU extension. */
82 value = 0;
83 else
85 if (!((*link_info->callbacks->undefined_symbol)
86 (link_info, bfd_asymbol_name (symbol),
87 input_section->owner, input_section, reloc->address,
88 TRUE)))
89 abort ();
90 value = 0;
93 else
95 value = symbol->value
96 + symbol->section->output_offset
97 + symbol->section->output_section->vma;
100 /* Add the value contained in the relocation. */
101 value += reloc->addend;
103 return value;
106 void
107 bfd_perform_slip (abfd, slip, input_section, value)
108 bfd *abfd;
109 unsigned int slip;
110 asection *input_section;
111 bfd_vma value;
113 asymbol **s;
115 s = _bfd_generic_link_get_symbols (abfd);
116 BFD_ASSERT (s != (asymbol **) NULL);
118 /* Find all symbols past this point, and make them know
119 what's happened. */
120 while (*s)
122 asymbol *p = *s;
123 if (p->section == input_section)
125 /* This was pointing into this section, so mangle it. */
126 if (p->value > value)
128 p->value -= slip;
129 if (p->udata.p != NULL)
131 struct generic_link_hash_entry *h;
133 h = (struct generic_link_hash_entry *) p->udata.p;
134 BFD_ASSERT (h->root.type == bfd_link_hash_defined
135 || h->root.type == bfd_link_hash_defweak);
136 h->root.u.def.value -= slip;
137 BFD_ASSERT (h->root.u.def.value == p->value);
141 s++;
145 bfd_boolean
146 bfd_coff_reloc16_relax_section (abfd, input_section, link_info, again)
147 bfd *abfd;
148 asection *input_section;
149 struct bfd_link_info *link_info;
150 bfd_boolean *again;
152 /* Get enough memory to hold the stuff. */
153 bfd *input_bfd = input_section->owner;
154 unsigned *shrinks;
155 unsigned shrink = 0;
156 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
157 arelent **reloc_vector = NULL;
158 long reloc_count;
160 if (link_info->relocatable)
161 (*link_info->callbacks->einfo)
162 (_("%P%F: --relax and -r may not be used together\n"));
164 /* We only do global relaxation once. It is not safe to do it multiple
165 times (see discussion of the "shrinks" array below). */
166 *again = FALSE;
168 if (reloc_size < 0)
169 return FALSE;
171 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
172 if (!reloc_vector && reloc_size > 0)
173 return FALSE;
175 /* Get the relocs and think about them. */
176 reloc_count =
177 bfd_canonicalize_reloc (input_bfd, input_section, reloc_vector,
178 _bfd_generic_link_get_symbols (input_bfd));
179 if (reloc_count < 0)
181 free (reloc_vector);
182 return FALSE;
185 /* The reloc16.c and related relaxing code is very simple, the price
186 for that simplicity is we can only call this function once for
187 each section.
189 So, to get the best results within that limitation, we do multiple
190 relaxing passes over each section here. That involves keeping track
191 of the "shrink" at each reloc in the section. This allows us to
192 accurately determine the relative location of two relocs within
193 this section.
195 In theory, if we kept the "shrinks" array for each section for the
196 entire link, we could use the generic relaxing code in the linker
197 and get better results, particularly for jsr->bsr and 24->16 bit
198 memory reference relaxations. */
200 if (reloc_count > 0)
202 int another_pass = 0;
203 bfd_size_type amt;
205 /* Allocate and initialize the shrinks array for this section.
206 The last element is used as an accumulator of shrinks. */
207 amt = reloc_count + 1;
208 amt *= sizeof (unsigned);
209 shrinks = (unsigned *) bfd_zmalloc (amt);
211 /* Loop until nothing changes in this section. */
214 arelent **parent;
215 unsigned int i;
216 long j;
218 another_pass = 0;
220 for (i = 0, parent = reloc_vector; *parent; parent++, i++)
222 /* Let the target/machine dependent code examine each reloc
223 in this section and attempt to shrink it. */
224 shrink = bfd_coff_reloc16_estimate (abfd, input_section, *parent,
225 shrinks[i], link_info);
227 /* If it shrunk, note it in the shrinks array and set up for
228 another pass. */
229 if (shrink != shrinks[i])
231 another_pass = 1;
232 for (j = i + 1; j <= reloc_count; j++)
233 shrinks[j] += shrink - shrinks[i];
237 while (another_pass);
239 shrink = shrinks[reloc_count];
240 free ((char *) shrinks);
243 input_section->rawsize = input_section->size;
244 input_section->size -= shrink;
245 free ((char *) reloc_vector);
246 return TRUE;
249 bfd_byte *
250 bfd_coff_reloc16_get_relocated_section_contents (in_abfd,
251 link_info,
252 link_order,
253 data,
254 relocatable,
255 symbols)
256 bfd *in_abfd;
257 struct bfd_link_info *link_info;
258 struct bfd_link_order *link_order;
259 bfd_byte *data;
260 bfd_boolean relocatable;
261 asymbol **symbols;
263 /* Get enough memory to hold the stuff. */
264 bfd *input_bfd = link_order->u.indirect.section->owner;
265 asection *input_section = link_order->u.indirect.section;
266 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
267 arelent **reloc_vector;
268 long reloc_count;
269 bfd_size_type sz;
271 if (reloc_size < 0)
272 return NULL;
274 /* If producing relocatable output, don't bother to relax. */
275 if (relocatable)
276 return bfd_generic_get_relocated_section_contents (in_abfd, link_info,
277 link_order,
278 data, relocatable,
279 symbols);
281 /* Read in the section. */
282 sz = input_section->rawsize ? input_section->rawsize : input_section->size;
283 if (!bfd_get_section_contents (input_bfd, input_section, data, 0, sz))
284 return NULL;
286 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
287 if (!reloc_vector && reloc_size != 0)
288 return NULL;
290 reloc_count = bfd_canonicalize_reloc (input_bfd,
291 input_section,
292 reloc_vector,
293 symbols);
294 if (reloc_count < 0)
296 free (reloc_vector);
297 return NULL;
300 if (reloc_count > 0)
302 arelent **parent = reloc_vector;
303 arelent *reloc;
304 unsigned int dst_address = 0;
305 unsigned int src_address = 0;
306 unsigned int run;
307 unsigned int idx;
309 /* Find how long a run we can do. */
310 while (dst_address < link_order->size)
312 reloc = *parent;
313 if (reloc)
315 /* Note that the relaxing didn't tie up the addresses in the
316 relocation, so we use the original address to work out the
317 run of non-relocated data. */
318 run = reloc->address - src_address;
319 parent++;
321 else
323 run = link_order->size - dst_address;
326 /* Copy the bytes. */
327 for (idx = 0; idx < run; idx++)
328 data[dst_address++] = data[src_address++];
330 /* Now do the relocation. */
331 if (reloc)
333 bfd_coff_reloc16_extra_cases (input_bfd, link_info, link_order,
334 reloc, data, &src_address,
335 &dst_address);
339 free ((char *) reloc_vector);
340 return data;