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[/] [openrisc/] [trunk/] [gnu-stable/] [gdb-7.2/] [bfd/] [elf-vxworks.c] - Blame information for rev 841

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Line No. Rev Author Line
1 330 jeremybenn
/* VxWorks support for ELF
2
   Copyright 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
3
 
4
   This file is part of BFD, the Binary File Descriptor library.
5
 
6
   This program is free software; you can redistribute it and/or modify
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   it under the terms of the GNU General Public License as published by
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   the Free Software Foundation; either version 3 of the License, or
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   (at your option) any later version.
10
 
11
   This program is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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   GNU General Public License for more details.
15
 
16
   You should have received a copy of the GNU General Public License
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   along with this program; if not, write to the Free Software
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   Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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   MA 02111-1307, USA.  */
20
 
21
/* This file provides routines used by all VxWorks targets.  */
22
 
23
#include "sysdep.h"
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#include "bfd.h"
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#include "libbfd.h"
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#include "elf-bfd.h"
27
#include "elf-vxworks.h"
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#include "elf/vxworks.h"
29
 
30
/* Return true if symbol NAME, as defined by ABFD, is one of the special
31
   __GOTT_BASE__ or __GOTT_INDEX__ symbols.  */
32
 
33
static bfd_boolean
34
elf_vxworks_gott_symbol_p (bfd *abfd, const char *name)
35
{
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  char leading;
37
 
38
  leading = bfd_get_symbol_leading_char (abfd);
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  if (leading)
40
    {
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      if (*name != leading)
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        return FALSE;
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      name++;
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    }
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  return (strcmp (name, "__GOTT_BASE__") == 0
46
          || strcmp (name, "__GOTT_INDEX__") == 0);
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}
48
 
49
/* Tweak magic VxWorks symbols as they are loaded.  */
50
bfd_boolean
51
elf_vxworks_add_symbol_hook (bfd *abfd,
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                             struct bfd_link_info *info,
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                             Elf_Internal_Sym *sym,
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                             const char **namep,
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                             flagword *flagsp,
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                             asection **secp ATTRIBUTE_UNUSED,
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                             bfd_vma *valp ATTRIBUTE_UNUSED)
58
{
59
  /* Ideally these "magic" symbols would be exported by libc.so.1
60
     which would be found via a DT_NEEDED tag, and then handled
61
     specially by the linker at runtime.  Except shared libraries
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     don't even link to libc.so.1 by default...
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     If the symbol is imported from, or will be put in a shared library,
64
     give the symbol weak binding to get the desired samantics.
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     This transformation will be undone in
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     elf_i386_vxworks_link_output_symbol_hook. */
67
  if ((info->shared || abfd->flags & DYNAMIC)
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      && elf_vxworks_gott_symbol_p (abfd, *namep))
69
    {
70
      sym->st_info = ELF_ST_INFO (STB_WEAK, ELF_ST_TYPE (sym->st_info));
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      *flagsp |= BSF_WEAK;
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    }
73
 
74
  return TRUE;
75
}
76
 
77
/* Perform VxWorks-specific handling of the create_dynamic_sections hook.
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   When creating an executable, set *SRELPLT2_OUT to the .rel(a).plt.unloaded
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   section.  */
80
 
81
bfd_boolean
82
elf_vxworks_create_dynamic_sections (bfd *dynobj, struct bfd_link_info *info,
83
                                     asection **srelplt2_out)
84
{
85
  struct elf_link_hash_table *htab;
86
  const struct elf_backend_data *bed;
87
  asection *s;
88
 
89
  htab = elf_hash_table (info);
90
  bed = get_elf_backend_data (dynobj);
91
 
92
  if (!info->shared)
93
    {
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      s = bfd_make_section_with_flags (dynobj,
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                                       bed->default_use_rela_p
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                                       ? ".rela.plt.unloaded"
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                                       : ".rel.plt.unloaded",
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                                       SEC_HAS_CONTENTS | SEC_IN_MEMORY
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                                       | SEC_READONLY | SEC_LINKER_CREATED);
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      if (s == NULL
101
          || !bfd_set_section_alignment (dynobj, s, bed->s->log_file_align))
102
        return FALSE;
103
 
104
      *srelplt2_out = s;
105
    }
106
 
107
  /* Mark the GOT and PLT symbols as having relocations; they might
108
     not, but we won't know for sure until we build the GOT in
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     finish_dynamic_symbol.  Also make sure that the GOT symbol
110
     is entered into the dynamic symbol table; the loader uses it
111
     to initialize __GOTT_BASE__[__GOTT_INDEX__].  */
112
  if (htab->hgot)
113
    {
114
      htab->hgot->indx = -2;
115
      htab->hgot->other &= ~ELF_ST_VISIBILITY (-1);
116
      htab->hgot->forced_local = 0;
117
      if (!bfd_elf_link_record_dynamic_symbol (info, htab->hgot))
118
        return FALSE;
119
    }
120
  if (htab->hplt)
121
    {
122
      htab->hplt->indx = -2;
123
      htab->hplt->type = STT_FUNC;
124
    }
125
 
126
  return TRUE;
127
}
128
 
129
/* Tweak magic VxWorks symbols as they are written to the output file.  */
130
int
131
elf_vxworks_link_output_symbol_hook (struct bfd_link_info *info
132
                                       ATTRIBUTE_UNUSED,
133
                                     const char *name,
134
                                     Elf_Internal_Sym *sym,
135
                                     asection *input_sec ATTRIBUTE_UNUSED,
136
                                     struct elf_link_hash_entry *h)
137
{
138
  /* Reverse the effects of the hack in elf_vxworks_add_symbol_hook.  */
139
  if (h
140
      && h->root.type == bfd_link_hash_undefweak
141
      && elf_vxworks_gott_symbol_p (h->root.u.undef.abfd, name))
142
    sym->st_info = ELF_ST_INFO (STB_GLOBAL, ELF_ST_TYPE (sym->st_info));
143
 
144
  return 1;
145
}
146
 
147
/* Copy relocations into the output file.  Fixes up relocations against PLT
148
   entries, then calls the generic routine.  */
149
 
150
bfd_boolean
151
elf_vxworks_emit_relocs (bfd *output_bfd,
152
                         asection *input_section,
153
                         Elf_Internal_Shdr *input_rel_hdr,
154
                         Elf_Internal_Rela *internal_relocs,
155
                         struct elf_link_hash_entry **rel_hash)
156
{
157
  const struct elf_backend_data *bed;
158
  int j;
159
 
160
  bed = get_elf_backend_data (output_bfd);
161
 
162
  if (output_bfd->flags & (DYNAMIC|EXEC_P))
163
    {
164
      Elf_Internal_Rela *irela;
165
      Elf_Internal_Rela *irelaend;
166
      struct elf_link_hash_entry **hash_ptr;
167
 
168
      for (irela = internal_relocs,
169
             irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr)
170
                                 * bed->s->int_rels_per_ext_rel),
171
             hash_ptr = rel_hash;
172
           irela < irelaend;
173
           irela += bed->s->int_rels_per_ext_rel,
174
             hash_ptr++)
175
        {
176
          if (*hash_ptr
177
              && (*hash_ptr)->def_dynamic
178
              && !(*hash_ptr)->def_regular
179
              && ((*hash_ptr)->root.type == bfd_link_hash_defined
180
                  || (*hash_ptr)->root.type == bfd_link_hash_defweak)
181
              && (*hash_ptr)->root.u.def.section->output_section != NULL)
182
            {
183
              /* This is a relocation from an executable or shared
184
                 library against a symbol in a different shared
185
                 library.  We are creating a definition in the output
186
                 file but it does not come from any of our normal (.o)
187
                 files. ie. a PLT stub.  Normally this would be a
188
                 relocation against against SHN_UNDEF with the VMA of
189
                 the PLT stub.  This upsets the VxWorks loader.
190
                 Convert it to a section-relative relocation.  This
191
                 gets some other symbols (for instance .dynbss), but
192
                 is conservatively correct.  */
193
              for (j = 0; j < bed->s->int_rels_per_ext_rel; j++)
194
                {
195
                  asection *sec = (*hash_ptr)->root.u.def.section;
196
                  int this_idx = sec->output_section->target_index;
197
 
198
                  irela[j].r_info
199
                    = ELF32_R_INFO (this_idx, ELF32_R_TYPE (irela[j].r_info));
200
                  irela[j].r_addend += (*hash_ptr)->root.u.def.value;
201
                  irela[j].r_addend += sec->output_offset;
202
                }
203
              /* Stop the generic routine adjusting this entry.  */
204
              *hash_ptr = NULL;
205
            }
206
        }
207
    }
208
  return _bfd_elf_link_output_relocs (output_bfd, input_section,
209
                                      input_rel_hdr, internal_relocs,
210
                                      rel_hash);
211
}
212
 
213
 
214
/* Set the sh_link and sh_info fields on the static plt relocation secton.  */
215
 
216
void
217
elf_vxworks_final_write_processing (bfd *abfd,
218
                                    bfd_boolean linker ATTRIBUTE_UNUSED)
219
{
220
  asection * sec;
221
  struct bfd_elf_section_data *d;
222
 
223
  sec = bfd_get_section_by_name (abfd, ".rel.plt.unloaded");
224
  if (!sec)
225
    sec = bfd_get_section_by_name (abfd, ".rela.plt.unloaded");
226
  if (!sec)
227
    return;
228
  d = elf_section_data (sec);
229
  d->this_hdr.sh_link = elf_tdata (abfd)->symtab_section;
230
  sec = bfd_get_section_by_name (abfd, ".plt");
231
  if (sec)
232
    d->this_hdr.sh_info = elf_section_data (sec)->this_idx;
233
}
234
 
235
/* Add the dynamic entries required by VxWorks.  These point to the
236
   tls sections.  */
237
 
238
bfd_boolean
239
elf_vxworks_add_dynamic_entries (bfd *output_bfd, struct bfd_link_info *info)
240
{
241
  if (bfd_get_section_by_name (output_bfd, ".tls_data"))
242
    {
243
      if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_START, 0)
244
          || !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_SIZE, 0)
245
          || !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_ALIGN, 0))
246
        return FALSE;
247
    }
248
  if (bfd_get_section_by_name (output_bfd, ".tls_vars"))
249
    {
250
      if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_START, 0)
251
          || !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_SIZE, 0))
252
        return FALSE;
253
    }
254
  return TRUE;
255
}
256
 
257
/* If *DYN is one of the VxWorks-specific dynamic entries, then fill
258
   in the value now  and return TRUE.  Otherwise return FALSE.  */
259
 
260
bfd_boolean
261
elf_vxworks_finish_dynamic_entry (bfd *output_bfd, Elf_Internal_Dyn *dyn)
262
{
263
  asection *sec;
264
 
265
  switch (dyn->d_tag)
266
    {
267
    default:
268
      return FALSE;
269
 
270
    case DT_VX_WRS_TLS_DATA_START:
271
      sec = bfd_get_section_by_name (output_bfd, ".tls_data");
272
      dyn->d_un.d_ptr = sec->vma;
273
      break;
274
 
275
    case DT_VX_WRS_TLS_DATA_SIZE:
276
      sec = bfd_get_section_by_name (output_bfd, ".tls_data");
277
      dyn->d_un.d_val = sec->size;
278
      break;
279
 
280
    case DT_VX_WRS_TLS_DATA_ALIGN:
281
      sec = bfd_get_section_by_name (output_bfd, ".tls_data");
282
      dyn->d_un.d_val
283
        = (bfd_size_type)1 << bfd_get_section_alignment (abfd, sec);
284
      break;
285
 
286
    case DT_VX_WRS_TLS_VARS_START:
287
      sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
288
      dyn->d_un.d_ptr = sec->vma;
289
      break;
290
 
291
    case DT_VX_WRS_TLS_VARS_SIZE:
292
      sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
293
      dyn->d_un.d_val = sec->size;
294
      break;
295
    }
296
  return TRUE;
297
}
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