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[binutils.git] / bfd / reloc16.c
blobb4087cbd58abd09e3609ff03abc1a2e45233184d
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, 2007 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 /* We only do global relaxation once. It is not safe to do it multiple
161 times (see discussion of the "shrinks" array below). */
162 *again = FALSE;
164 if (reloc_size < 0)
165 return FALSE;
167 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
168 if (!reloc_vector && reloc_size > 0)
169 return FALSE;
171 /* Get the relocs and think about them. */
172 reloc_count =
173 bfd_canonicalize_reloc (input_bfd, input_section, reloc_vector,
174 _bfd_generic_link_get_symbols (input_bfd));
175 if (reloc_count < 0)
177 free (reloc_vector);
178 return FALSE;
181 /* The reloc16.c and related relaxing code is very simple, the price
182 for that simplicity is we can only call this function once for
183 each section.
185 So, to get the best results within that limitation, we do multiple
186 relaxing passes over each section here. That involves keeping track
187 of the "shrink" at each reloc in the section. This allows us to
188 accurately determine the relative location of two relocs within
189 this section.
191 In theory, if we kept the "shrinks" array for each section for the
192 entire link, we could use the generic relaxing code in the linker
193 and get better results, particularly for jsr->bsr and 24->16 bit
194 memory reference relaxations. */
196 if (reloc_count > 0)
198 int another_pass = 0;
199 bfd_size_type amt;
201 /* Allocate and initialize the shrinks array for this section.
202 The last element is used as an accumulator of shrinks. */
203 amt = reloc_count + 1;
204 amt *= sizeof (unsigned);
205 shrinks = (unsigned *) bfd_zmalloc (amt);
207 /* Loop until nothing changes in this section. */
210 arelent **parent;
211 unsigned int i;
212 long j;
214 another_pass = 0;
216 for (i = 0, parent = reloc_vector; *parent; parent++, i++)
218 /* Let the target/machine dependent code examine each reloc
219 in this section and attempt to shrink it. */
220 shrink = bfd_coff_reloc16_estimate (abfd, input_section, *parent,
221 shrinks[i], link_info);
223 /* If it shrunk, note it in the shrinks array and set up for
224 another pass. */
225 if (shrink != shrinks[i])
227 another_pass = 1;
228 for (j = i + 1; j <= reloc_count; j++)
229 shrinks[j] += shrink - shrinks[i];
233 while (another_pass);
235 shrink = shrinks[reloc_count];
236 free ((char *) shrinks);
239 input_section->rawsize = input_section->size;
240 input_section->size -= shrink;
241 free ((char *) reloc_vector);
242 return TRUE;
245 bfd_byte *
246 bfd_coff_reloc16_get_relocated_section_contents (in_abfd,
247 link_info,
248 link_order,
249 data,
250 relocatable,
251 symbols)
252 bfd *in_abfd;
253 struct bfd_link_info *link_info;
254 struct bfd_link_order *link_order;
255 bfd_byte *data;
256 bfd_boolean relocatable;
257 asymbol **symbols;
259 /* Get enough memory to hold the stuff. */
260 bfd *input_bfd = link_order->u.indirect.section->owner;
261 asection *input_section = link_order->u.indirect.section;
262 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
263 arelent **reloc_vector;
264 long reloc_count;
265 bfd_size_type sz;
267 if (reloc_size < 0)
268 return NULL;
270 /* If producing relocatable output, don't bother to relax. */
271 if (relocatable)
272 return bfd_generic_get_relocated_section_contents (in_abfd, link_info,
273 link_order,
274 data, relocatable,
275 symbols);
277 /* Read in the section. */
278 sz = input_section->rawsize ? input_section->rawsize : input_section->size;
279 if (!bfd_get_section_contents (input_bfd, input_section, data, 0, sz))
280 return NULL;
282 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
283 if (!reloc_vector && reloc_size != 0)
284 return NULL;
286 reloc_count = bfd_canonicalize_reloc (input_bfd,
287 input_section,
288 reloc_vector,
289 symbols);
290 if (reloc_count < 0)
292 free (reloc_vector);
293 return NULL;
296 if (reloc_count > 0)
298 arelent **parent = reloc_vector;
299 arelent *reloc;
300 unsigned int dst_address = 0;
301 unsigned int src_address = 0;
302 unsigned int run;
303 unsigned int idx;
305 /* Find how long a run we can do. */
306 while (dst_address < link_order->size)
308 reloc = *parent;
309 if (reloc)
311 /* Note that the relaxing didn't tie up the addresses in the
312 relocation, so we use the original address to work out the
313 run of non-relocated data. */
314 run = reloc->address - src_address;
315 parent++;
317 else
319 run = link_order->size - dst_address;
322 /* Copy the bytes. */
323 for (idx = 0; idx < run; idx++)
324 data[dst_address++] = data[src_address++];
326 /* Now do the relocation. */
327 if (reloc)
329 bfd_coff_reloc16_extra_cases (input_bfd, link_info, link_order,
330 reloc, data, &src_address,
331 &dst_address);
335 free ((char *) reloc_vector);
336 return data;