1 // copy-relocs.cc -- handle COPY relocations for gold.
3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
26 #include "copy-relocs.h"
31 // Copy_relocs::Copy_reloc_entry methods.
33 // Emit the reloc if appropriate.
35 template<int sh_type
, int size
, bool big_endian
>
37 Copy_relocs
<sh_type
, size
, big_endian
>::Copy_reloc_entry::emit(
38 Output_data_reloc
<sh_type
, true, size
, big_endian
>* reloc_section
)
40 // If the symbol is no longer defined in a dynamic object, then we
41 // emitted a COPY relocation, and we do not want to emit this
42 // dynamic relocation.
43 if (this->sym_
->is_from_dynobj())
44 reloc_section
->add_global(this->sym_
, this->reloc_type_
,
45 this->output_section_
, this->relobj_
,
46 this->shndx_
, this->address_
,
50 // Copy_relocs methods.
52 // Handle a relocation against a symbol which may force us to generate
55 template<int sh_type
, int size
, bool big_endian
>
57 Copy_relocs
<sh_type
, size
, big_endian
>::copy_reloc(
60 Sized_symbol
<size
>* sym
,
61 Sized_relobj
<size
, big_endian
>* object
,
63 Output_section
*output_section
,
65 Output_data_reloc
<sh_type
, true, size
, big_endian
>* reloc_section
)
67 if (this->need_copy_reloc(sym
, object
, shndx
))
68 this->emit_copy_reloc(symtab
, layout
, sym
, reloc_section
);
71 // We may not need a COPY relocation. Save this relocation to
72 // possibly be emitted later.
73 this->save(sym
, object
, shndx
, output_section
, rel
);
77 // Return whether we need a COPY reloc for a relocation against SYM.
78 // The relocation is begin applied to section SHNDX in OBJECT.
80 template<int sh_type
, int size
, bool big_endian
>
82 Copy_relocs
<sh_type
, size
, big_endian
>::need_copy_reloc(
83 Sized_symbol
<size
>* sym
,
84 Sized_relobj
<size
, big_endian
>* object
,
85 unsigned int shndx
) const
87 if (!parameters
->options().copyreloc())
90 if (sym
->symsize() == 0)
93 // If this is a readonly section, then we need a COPY reloc.
94 // Otherwise we can use a dynamic reloc. Note that calling
95 // section_flags here can be slow, as the information is not cached;
96 // fortunately we shouldn't see too many potential COPY relocs.
97 if ((object
->section_flags(shndx
) & elfcpp::SHF_WRITE
) == 0)
103 // Emit a COPY relocation for SYM.
105 template<int sh_type
, int size
, bool big_endian
>
107 Copy_relocs
<sh_type
, size
, big_endian
>::emit_copy_reloc(
108 Symbol_table
* symtab
,
110 Sized_symbol
<size
>* sym
,
111 Output_data_reloc
<sh_type
, true, size
, big_endian
>* reloc_section
)
113 // We should not be here if -z nocopyreloc is given.
114 gold_assert(parameters
->options().copyreloc());
116 typename
elfcpp::Elf_types
<size
>::Elf_WXword symsize
= sym
->symsize();
118 // There is no defined way to determine the required alignment of
119 // the symbol. We know that the symbol is defined in a dynamic
120 // object. We start with the alignment of the section in which it
121 // is defined; presumably we do not require an alignment larger than
122 // that. Then we reduce that alignment if the symbol is not aligned
123 // within the section.
124 gold_assert(sym
->is_from_dynobj());
126 unsigned int shndx
= sym
->shndx(&is_ordinary
);
127 gold_assert(is_ordinary
);
128 typename
elfcpp::Elf_types
<size
>::Elf_WXword addralign
=
129 sym
->object()->section_addralign(shndx
);
131 typename Sized_symbol
<size
>::Value_type value
= sym
->value();
132 while ((value
& (addralign
- 1)) != 0)
135 if (this->dynbss_
== NULL
)
137 this->dynbss_
= new Output_data_space(addralign
, "** dynbss");
138 layout
->add_output_section_data(".bss",
140 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
141 this->dynbss_
, false, false, false,
145 Output_data_space
* dynbss
= this->dynbss_
;
147 if (addralign
> dynbss
->addralign())
148 dynbss
->set_space_alignment(addralign
);
150 section_size_type dynbss_size
=
151 convert_to_section_size_type(dynbss
->current_data_size());
152 dynbss_size
= align_address(dynbss_size
, addralign
);
153 section_size_type offset
= dynbss_size
;
154 dynbss
->set_current_data_size(dynbss_size
+ symsize
);
156 // Define the symbol as being copied.
157 symtab
->define_with_copy_reloc(sym
, dynbss
, offset
);
159 // Add the COPY relocation to the dynamic reloc section.
160 this->add_copy_reloc(sym
, offset
, reloc_section
);
163 // Add a COPY relocation for SYM to RELOC_SECTION.
165 template<int sh_type
, int size
, bool big_endian
>
167 Copy_relocs
<sh_type
, size
, big_endian
>::add_copy_reloc(
169 section_size_type offset
,
170 Output_data_reloc
<sh_type
, true, size
, big_endian
>* reloc_section
)
172 reloc_section
->add_global(sym
, this->copy_reloc_type_
, this->dynbss_
,
176 // Save a relocation to possibly be emitted later.
178 template<int sh_type
, int size
, bool big_endian
>
180 Copy_relocs
<sh_type
, size
, big_endian
>::save(
182 Sized_relobj
<size
, big_endian
>* object
,
184 Output_section
* output_section
,
187 unsigned int reloc_type
= elfcpp::elf_r_type
<size
>(rel
.get_r_info());
188 typename
elfcpp::Elf_types
<size
>::Elf_Addr addend
=
189 Reloc_types
<sh_type
, size
, big_endian
>::get_reloc_addend_noerror(&rel
);
190 this->entries_
.push_back(Copy_reloc_entry(sym
, reloc_type
, object
, shndx
,
191 output_section
, rel
.get_r_offset(),
195 // Emit any saved relocs.
197 template<int sh_type
, int size
, bool big_endian
>
199 Copy_relocs
<sh_type
, size
, big_endian
>::emit(
200 Output_data_reloc
<sh_type
, true, size
, big_endian
>* reloc_section
)
202 for (typename
Copy_reloc_entries::iterator p
= this->entries_
.begin();
203 p
!= this->entries_
.end();
205 p
->emit(reloc_section
);
207 // We no longer need the saved information.
208 this->entries_
.clear();
211 // Instantiate the templates we need.
213 #ifdef HAVE_TARGET_32_LITTLE
215 class Copy_relocs
<elfcpp::SHT_REL
, 32, false>;
218 class Copy_relocs
<elfcpp::SHT_RELA
, 32, false>;
221 #ifdef HAVE_TARGET_32_BIG
223 class Copy_relocs
<elfcpp::SHT_REL
, 32, true>;
226 class Copy_relocs
<elfcpp::SHT_RELA
, 32, true>;
229 #ifdef HAVE_TARGET_64_LITTLE
231 class Copy_relocs
<elfcpp::SHT_REL
, 64, false>;
234 class Copy_relocs
<elfcpp::SHT_RELA
, 64, false>;
237 #ifdef HAVE_TARGET_64_BIG
239 class Copy_relocs
<elfcpp::SHT_REL
, 64, true>;
242 class Copy_relocs
<elfcpp::SHT_RELA
, 64, true>;
245 } // End namespace gold.