2009-12-02 Rafael Avila de Espindola <espindola@google.com>
[binutils.git] / bfd / elf-vxworks.c
blob06edf8dce61def3f9ce6f5384f297fa8cdea3630
1 /* VxWorks support for ELF
2 Copyright 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston,
19 MA 02111-1307, USA. */
21 /* This file provides routines used by all VxWorks targets. */
23 #include "sysdep.h"
24 #include "bfd.h"
25 #include "libbfd.h"
26 #include "elf-bfd.h"
27 #include "elf-vxworks.h"
28 #include "elf/vxworks.h"
30 /* Return true if symbol NAME, as defined by ABFD, is one of the special
31 __GOTT_BASE__ or __GOTT_INDEX__ symbols. */
33 static bfd_boolean
34 elf_vxworks_gott_symbol_p (bfd *abfd, const char *name)
36 char leading;
38 leading = bfd_get_symbol_leading_char (abfd);
39 if (leading)
41 if (*name != leading)
42 return FALSE;
43 name++;
45 return (strcmp (name, "__GOTT_BASE__") == 0
46 || strcmp (name, "__GOTT_INDEX__") == 0);
49 /* Tweak magic VxWorks symbols as they are loaded. */
50 bfd_boolean
51 elf_vxworks_add_symbol_hook (bfd *abfd,
52 struct bfd_link_info *info,
53 Elf_Internal_Sym *sym,
54 const char **namep,
55 flagword *flagsp,
56 asection **secp ATTRIBUTE_UNUSED,
57 bfd_vma *valp ATTRIBUTE_UNUSED)
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
62 don't even link to libc.so.1 by default...
63 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.
65 This transformation will be undone in
66 elf_i386_vxworks_link_output_symbol_hook. */
67 if ((info->shared || abfd->flags & DYNAMIC)
68 && elf_vxworks_gott_symbol_p (abfd, *namep))
70 sym->st_info = ELF_ST_INFO (STB_WEAK, ELF_ST_TYPE (sym->st_info));
71 *flagsp |= BSF_WEAK;
74 return TRUE;
77 /* Perform VxWorks-specific handling of the create_dynamic_sections hook.
78 When creating an executable, set *SRELPLT2_OUT to the .rel(a).plt.unloaded
79 section. */
81 bfd_boolean
82 elf_vxworks_create_dynamic_sections (bfd *dynobj, struct bfd_link_info *info,
83 asection **srelplt2_out)
85 struct elf_link_hash_table *htab;
86 const struct elf_backend_data *bed;
87 asection *s;
89 htab = elf_hash_table (info);
90 bed = get_elf_backend_data (dynobj);
92 if (!info->shared)
94 s = bfd_make_section_with_flags (dynobj,
95 bed->default_use_rela_p
96 ? ".rela.plt.unloaded"
97 : ".rel.plt.unloaded",
98 SEC_HAS_CONTENTS | SEC_IN_MEMORY
99 | SEC_READONLY | SEC_LINKER_CREATED);
100 if (s == NULL
101 || !bfd_set_section_alignment (dynobj, s, bed->s->log_file_align))
102 return FALSE;
104 *srelplt2_out = s;
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
109 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)
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;
120 if (htab->hplt)
122 htab->hplt->indx = -2;
123 htab->hplt->type = STT_FUNC;
126 return TRUE;
129 /* Tweak magic VxWorks symbols as they are written to the output file. */
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)
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));
144 return 1;
147 /* Copy relocations into the output file. Fixes up relocations against PLT
148 entries, then calls the generic routine. */
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)
157 const struct elf_backend_data *bed;
158 int j;
160 bed = get_elf_backend_data (output_bfd);
162 if (output_bfd->flags & (DYNAMIC|EXEC_P))
164 Elf_Internal_Rela *irela;
165 Elf_Internal_Rela *irelaend;
166 struct elf_link_hash_entry **hash_ptr;
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++)
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)
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++)
195 asection *sec = (*hash_ptr)->root.u.def.section;
196 int this_idx = sec->output_section->target_index;
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;
203 /* Stop the generic routine adjusting this entry. */
204 *hash_ptr = NULL;
208 return _bfd_elf_link_output_relocs (output_bfd, input_section,
209 input_rel_hdr, internal_relocs,
210 rel_hash);
214 /* Set the sh_link and sh_info fields on the static plt relocation secton. */
216 void
217 elf_vxworks_final_write_processing (bfd *abfd,
218 bfd_boolean linker ATTRIBUTE_UNUSED)
220 asection * sec;
221 struct bfd_elf_section_data *d;
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;
235 /* Add the dynamic entries required by VxWorks. These point to the
236 tls sections. */
238 bfd_boolean
239 elf_vxworks_add_dynamic_entries (bfd *output_bfd, struct bfd_link_info *info)
241 if (bfd_get_section_by_name (output_bfd, ".tls_data"))
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;
248 if (bfd_get_section_by_name (output_bfd, ".tls_vars"))
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;
254 return TRUE;
257 /* If *DYN is one of the VxWorks-specific dynamic entries, then fill
258 in the value now and return TRUE. Otherwise return FALSE. */
260 bfd_boolean
261 elf_vxworks_finish_dynamic_entry (bfd *output_bfd, Elf_Internal_Dyn *dyn)
263 asection *sec;
265 switch (dyn->d_tag)
267 default:
268 return FALSE;
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;
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;
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;
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;
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;
296 return TRUE;