summaryrefslogtreecommitdiffstats
path: root/bfd/reloc16.c
blob: 768b288d824fd489e8e58a39c7a2673a3b11941e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
/* 8 and 16 bit COFF relocation functions, for BFD.
   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 2000, 2001,
   2002, 2003, 2004, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
   Written by Cygnus Support.

   This file is part of BFD, the Binary File Descriptor library.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */


/* Most of this hacked by Steve Chamberlain <sac@cygnus.com>.  */

/* These routines are used by coff-h8300 and coff-z8k to do
   relocation.

   FIXME: This code should be rewritten to support the new COFF
   linker.  Basically, they need to deal with COFF relocs rather than
   BFD generic relocs.  They should store the relocs in some location
   where coff_link_input_bfd can find them (and coff_link_input_bfd
   should be changed to use this location rather than rereading the
   file) (unless info->keep_memory is FALSE, in which case they should
   free up the relocs after dealing with them).  */

#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "bfdlink.h"
#include "genlink.h"
#include "coff/internal.h"
#include "libcoff.h"

bfd_vma
bfd_coff_reloc16_get_value (reloc, link_info, input_section)
     arelent *reloc;
     struct bfd_link_info *link_info;
     asection *input_section;
{
  bfd_vma value;
  asymbol *symbol = *(reloc->sym_ptr_ptr);
  /* A symbol holds a pointer to a section, and an offset from the
     base of the section.  To relocate, we find where the section will
     live in the output and add that in.  */

  if (bfd_is_und_section (symbol->section)
      || bfd_is_com_section (symbol->section))
    {
      struct bfd_link_hash_entry *h;

      /* The symbol is undefined in this BFD.  Look it up in the
	 global linker hash table.  FIXME: This should be changed when
	 we convert this stuff to use a specific final_link function
	 and change the interface to bfd_relax_section to not require
	 the generic symbols.  */
      h = bfd_wrapped_link_hash_lookup (input_section->owner, link_info,
					bfd_asymbol_name (symbol),
					FALSE, FALSE, TRUE);
      if (h != (struct bfd_link_hash_entry *) NULL
	  && (h->type == bfd_link_hash_defined
	      || h->type == bfd_link_hash_defweak))
	value = (h->u.def.value
		 + h->u.def.section->output_section->vma
		 + h->u.def.section->output_offset);
      else if (h != (struct bfd_link_hash_entry *) NULL
	       && h->type == bfd_link_hash_common)
	value = h->u.c.size;
      else if (h != (struct bfd_link_hash_entry *) NULL
	       && h->type == bfd_link_hash_undefweak)
	/* This is a GNU extension.  */
	value = 0;
      else
	{
	  if (!((*link_info->callbacks->undefined_symbol)
		(link_info, bfd_asymbol_name (symbol),
		 input_section->owner, input_section, reloc->address,
		 TRUE)))
	    abort ();
	  value = 0;
	}
    }
  else
    {
      value = symbol->value
	+ symbol->section->output_offset
	+ symbol->section->output_section->vma;
    }

  /* Add the value contained in the relocation.  */
  value += reloc->addend;

  return value;
}

void
bfd_perform_slip (abfd, slip, input_section, value)
     bfd *abfd;
     unsigned int slip;
     asection *input_section;
     bfd_vma value;
{
  asymbol **s;

  s = _bfd_generic_link_get_symbols (abfd);
  BFD_ASSERT (s != (asymbol **) NULL);

  /* Find all symbols past this point, and make them know
     what's happened.  */
  while (*s)
    {
      asymbol *p = *s;
      if (p->section == input_section)
	{
	  /* This was pointing into this section, so mangle it.  */
	  if (p->value > value)
	    {
	      p->value -= slip;
	      if (p->udata.p != NULL)
		{
		  struct generic_link_hash_entry *h;

		  h = (struct generic_link_hash_entry *) p->udata.p;
		  BFD_ASSERT (h->root.type == bfd_link_hash_defined
			      || h->root.type == bfd_link_hash_defweak);
		  h->root.u.def.value -= slip;
		  BFD_ASSERT (h->root.u.def.value == p->value);
		}
	    }
	}
      s++;
    }
}

bfd_boolean
bfd_coff_reloc16_relax_section (abfd, input_section, link_info, again)
     bfd *abfd;
     asection *input_section;
     struct bfd_link_info *link_info;
     bfd_boolean *again;
{
  /* Get enough memory to hold the stuff.  */
  bfd *input_bfd = input_section->owner;
  unsigned *shrinks;
  unsigned shrink = 0;
  long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
  arelent **reloc_vector = NULL;
  long reloc_count;

  if (link_info->relocatable)
    (*link_info->callbacks->einfo)
      (_("%P%F: --relax and -r may not be used together\n"));

  /* We only do global relaxation once.  It is not safe to do it multiple
     times (see discussion of the "shrinks" array below).  */
  *again = FALSE;

  if (reloc_size < 0)
    return FALSE;

  reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
  if (!reloc_vector && reloc_size > 0)
    return FALSE;

  /* Get the relocs and think about them.  */
  reloc_count =
    bfd_canonicalize_reloc (input_bfd, input_section, reloc_vector,
			    _bfd_generic_link_get_symbols (input_bfd));
  if (reloc_count < 0)
    {
      free (reloc_vector);
      return FALSE;
    }

  /* The reloc16.c and related relaxing code is very simple, the price
     for that simplicity is we can only call this function once for
     each section.

     So, to get the best results within that limitation, we do multiple
     relaxing passes over each section here.  That involves keeping track
     of the "shrink" at each reloc in the section.  This allows us to
     accurately determine the relative location of two relocs within
     this section.

     In theory, if we kept the "shrinks" array for each section for the
     entire link, we could use the generic relaxing code in the linker
     and get better results, particularly for jsr->bsr and 24->16 bit
     memory reference relaxations.  */

  if (reloc_count > 0)
    {
      int another_pass = 0;
      bfd_size_type amt;

      /* Allocate and initialize the shrinks array for this section.
	 The last element is used as an accumulator of shrinks.  */
      amt = reloc_count + 1;
      amt *= sizeof (unsigned);
      shrinks = (unsigned *) bfd_zmalloc (amt);

      /* Loop until nothing changes in this section.  */
      do
	{
	  arelent **parent;
	  unsigned int i;
	  long j;

	  another_pass = 0;

	  for (i = 0, parent = reloc_vector; *parent; parent++, i++)
	    {
	      /* Let the target/machine dependent code examine each reloc
		 in this section and attempt to shrink it.  */
	      shrink = bfd_coff_reloc16_estimate (abfd, input_section, *parent,
						  shrinks[i], link_info);

	      /* If it shrunk, note it in the shrinks array and set up for
		 another pass.  */
	      if (shrink != shrinks[i])
		{
		  another_pass = 1;
		  for (j = i + 1; j <= reloc_count; j++)
		    shrinks[j] += shrink - shrinks[i];
		}
	    }
	}
      while (another_pass);

      shrink = shrinks[reloc_count];
      free ((char *) shrinks);
    }

  input_section->rawsize = input_section->size;
  input_section->size -= shrink;
  free ((char *) reloc_vector);
  return TRUE;
}

bfd_byte *
bfd_coff_reloc16_get_relocated_section_contents (in_abfd,
						 link_info,
						 link_order,
						 data,
						 relocatable,
						 symbols)
     bfd *in_abfd;
     struct bfd_link_info *link_info;
     struct bfd_link_order *link_order;
     bfd_byte *data;
     bfd_boolean relocatable;
     asymbol **symbols;
{
  /* Get enough memory to hold the stuff.  */
  bfd *input_bfd = link_order->u.indirect.section->owner;
  asection *input_section = link_order->u.indirect.section;
  long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
  arelent **reloc_vector;
  long reloc_count;
  bfd_size_type sz;

  if (reloc_size < 0)
    return NULL;

  /* If producing relocatable output, don't bother to relax.  */
  if (relocatable)
    return bfd_generic_get_relocated_section_contents (in_abfd, link_info,
						       link_order,
						       data, relocatable,
						       symbols);

  /* Read in the section.  */
  sz = input_section->rawsize ? input_section->rawsize : input_section->size;
  if (!bfd_get_section_contents (input_bfd, input_section, data, 0, sz))
    return NULL;

  reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
  if (!reloc_vector && reloc_size != 0)
    return NULL;

  reloc_count = bfd_canonicalize_reloc (input_bfd,
					input_section,
					reloc_vector,
					symbols);
  if (reloc_count < 0)
    {
      free (reloc_vector);
      return NULL;
    }

  if (reloc_count > 0)
    {
      arelent **parent = reloc_vector;
      arelent *reloc;
      unsigned int dst_address = 0;
      unsigned int src_address = 0;
      unsigned int run;
      unsigned int idx;

      /* Find how long a run we can do.  */
      while (dst_address < link_order->size)
	{
	  reloc = *parent;
	  if (reloc)
	    {
	      /* Note that the relaxing didn't tie up the addresses in the
		 relocation, so we use the original address to work out the
		 run of non-relocated data.  */
	      run = reloc->address - src_address;
	      parent++;
	    }
	  else
	    {
	      run = link_order->size - dst_address;
	    }

	  /* Copy the bytes.  */
	  for (idx = 0; idx < run; idx++)
	    data[dst_address++] = data[src_address++];

	  /* Now do the relocation.  */
	  if (reloc)
	    {
	      bfd_coff_reloc16_extra_cases (input_bfd, link_info, link_order,
					    reloc, data, &src_address,
					    &dst_address);
	    }
	}
    }
  free ((char *) reloc_vector);
  return data;
}
OpenPOWER on IntegriCloud