1 // merge.cc -- handle section merging for gold
3 // Copyright 2006, 2007 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.
32 // Sort the entries in a merge mapping. The key is an input object, a
33 // section index in that object, and an offset in that section.
36 Output_merge_base::Merge_key_less::operator()(const Merge_key
& mk1
,
37 const Merge_key
& mk2
) const
39 // The order of different objects and different sections doesn't
40 // matter. We want to get consistent results across links so we
41 // don't use pointer comparison.
42 if (mk1
.object
!= mk2
.object
)
43 return mk1
.object
->name() < mk2
.object
->name();
44 if (mk1
.shndx
!= mk2
.shndx
)
45 return mk1
.shndx
< mk2
.shndx
;
46 return mk1
.offset
< mk2
.offset
;
49 // Add a mapping from an OFFSET in input section SHNDX in object
50 // OBJECT to an OUTPUT_OFFSET in a merged output section. This
51 // manages the mapping used to resolve relocations against merged
55 Output_merge_base::add_mapping(Relobj
* object
, unsigned int shndx
,
56 off_t offset
, off_t output_offset
)
62 std::pair
<Merge_map::iterator
, bool> ins
=
63 this->merge_map_
.insert(std::make_pair(mk
, output_offset
));
64 gold_assert(ins
.second
);
67 // Return the output address for an input address. The input address
68 // is at offset OFFSET in section SHNDX in OBJECT.
69 // OUTPUT_SECTION_ADDRESS is the address of the output section. If we
70 // know the address, set *POUTPUT and return true. Otherwise return
74 Output_merge_base::do_output_address(const Relobj
* object
, unsigned int shndx
,
76 uint64_t output_section_address
,
77 uint64_t* poutput
) const
79 gold_assert(output_section_address
== this->address());
85 Merge_map::const_iterator p
= this->merge_map_
.lower_bound(mk
);
87 // If MK is not in the map, lower_bound returns the next iterator
89 if (p
->first
.object
!= object
90 || p
->first
.shndx
!= shndx
91 || p
->first
.offset
!= offset
)
93 if (p
== this->merge_map_
.begin())
98 if (p
->first
.object
!= object
|| p
->first
.shndx
!= shndx
)
101 // Any input section is fully mapped: we don't need to know the size
102 // of the range starting at P->FIRST.OFFSET.
103 *poutput
= output_section_address
+ p
->second
+ (offset
- p
->first
.offset
);
107 // Compute the hash code for a fixed-size constant.
110 Output_merge_data::Merge_data_hash::operator()(Merge_data_key k
) const
112 const unsigned char* p
= this->pomd_
->constant(k
);
113 uint64_t entsize
= this->pomd_
->entsize();
115 // Fowler/Noll/Vo (FNV) hash (type FNV-1a).
116 if (sizeof(size_t) == 8)
118 size_t result
= static_cast<size_t>(14695981039346656037ULL);
119 for (uint64_t i
= 0; i
< entsize
; ++i
)
121 result
&= (size_t) *p
++;
122 result
*= 1099511628211ULL;
128 size_t result
= 2166136261UL;
129 for (uint64_t i
= 0; i
< entsize
; ++i
)
131 result
^= (size_t) *p
++;
132 result
*= 16777619UL;
138 // Return whether one hash table key equals another.
141 Output_merge_data::Merge_data_eq::operator()(Merge_data_key k1
,
142 Merge_data_key k2
) const
144 const unsigned char* p1
= this->pomd_
->constant(k1
);
145 const unsigned char* p2
= this->pomd_
->constant(k2
);
146 return memcmp(p1
, p2
, this->pomd_
->entsize()) == 0;
149 // Add a constant to the end of the section contents.
152 Output_merge_data::add_constant(const unsigned char* p
)
154 uint64_t entsize
= this->entsize();
155 if (this->len_
+ entsize
> this->alc_
)
158 this->alc_
= 128 * entsize
;
161 this->p_
= static_cast<unsigned char*>(realloc(this->p_
, this->alc_
));
162 if (this->p_
== NULL
)
163 gold_fatal("out of memory", true);
166 memcpy(this->p_
+ this->len_
, p
, entsize
);
167 this->len_
+= entsize
;
170 // Add the input section SHNDX in OBJECT to a merged output section
171 // which holds fixed length constants. Return whether we were able to
172 // handle the section; if not, it will be linked as usual without
176 Output_merge_data::do_add_input_section(Relobj
* object
, unsigned int shndx
)
179 const unsigned char* p
= object
->section_contents(shndx
, &len
);
181 uint64_t entsize
= this->entsize();
183 if (len
% entsize
!= 0)
186 for (off_t i
= 0; i
< len
; i
+= entsize
, p
+= entsize
)
188 // Add the constant to the section contents. If we find that it
189 // is already in the hash table, we will remove it again.
190 Merge_data_key k
= this->len_
;
191 this->add_constant(p
);
193 std::pair
<Merge_data_hashtable::iterator
, bool> ins
=
194 this->hashtable_
.insert(k
);
198 // Key was already present. Remove the copy we just added.
199 this->len_
-= entsize
;
203 // Record the offset of this constant in the output section.
204 this->add_mapping(object
, shndx
, i
, k
);
210 // Set the final data size in a merged output section with fixed size
214 Output_merge_data::do_set_address(uint64_t, off_t
)
216 // Release the memory we don't need.
217 this->p_
= static_cast<unsigned char*>(realloc(this->p_
, this->len_
));
218 gold_assert(this->p_
!= NULL
);
219 this->set_data_size(this->len_
);
222 // Write the data of a merged output section with fixed size constants
226 Output_merge_data::do_write(Output_file
* of
)
228 of
->write(this->offset(), this->p_
, this->len_
);
231 // Add an input section to a merged string section.
233 template<typename Char_type
>
235 Output_merge_string
<Char_type
>::do_add_input_section(Relobj
* object
,
239 const unsigned char* pdata
= object
->section_contents(shndx
, &len
);
241 const Char_type
* p
= reinterpret_cast<const Char_type
*>(pdata
);
243 if (len
% sizeof(Char_type
) != 0)
246 _("%s: %s: mergeable string section length not multiple of "
248 program_name
, object
->name().c_str());
251 len
/= sizeof(Char_type
);
257 for (const Char_type
* pl
= p
; *pl
!= 0; ++pl
)
263 _("%s: %s: entry in mergeable string section "
264 "not null terminated\n"),
265 program_name
, object
->name().c_str());
270 const Char_type
* str
= this->stringpool_
.add(p
, NULL
);
272 this->merged_strings_
.push_back(Merged_string(object
, shndx
, i
, str
));
281 // Set the final data size of a merged string section. This is where
282 // we finalize the mappings from the input sections to the output
285 template<typename Char_type
>
287 Output_merge_string
<Char_type
>::do_set_address(uint64_t, off_t
)
289 this->stringpool_
.set_string_offsets();
291 for (typename
Merged_strings::const_iterator p
=
292 this->merged_strings_
.begin();
293 p
!= this->merged_strings_
.end();
295 this->add_mapping(p
->object
, p
->shndx
, p
->offset
,
296 this->stringpool_
.get_offset(p
->string
));
298 this->set_data_size(this->stringpool_
.get_strtab_size());
301 this->merged_strings_
.clear();
304 // Write out a merged string section.
306 template<typename Char_type
>
308 Output_merge_string
<Char_type
>::do_write(Output_file
* of
)
310 this->stringpool_
.write(of
, this->offset());
313 // Instantiate the templates we need.
316 class Output_merge_string
<char>;
319 class Output_merge_string
<uint16_t>;
322 class Output_merge_string
<uint32_t>;
324 } // End namespace gold.
This page took 0.057886 seconds and 5 git commands to generate.