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
|
// compressed_output.cc -- manage compressed output sections for gold
// Copyright 2007 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// 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.
#include "gold.h"
#ifdef HAVE_ZLIB_H
#include <zlib.h>
#endif
#include "compressed_output.h"
#include "parameters.h"
namespace gold
{
// Compress UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns true
// if it successfully compressed, false if it failed for any reason
// (including not having zlib support in the library). If it returns
// true, it allocates memory for the compressed data using new, and
// sets *COMPRESSED_DATA and *COMPRESSED_SIZE to appropriate values.
#ifdef HAVE_ZLIB_H
static bool
zlib_compress(const char* uncompressed_data, unsigned long uncompressed_size,
char** compressed_data, unsigned long* compressed_size)
{
*compressed_size = uncompressed_size + uncompressed_size / 1000 + 128;
*compressed_data = new char[*compressed_size];
int compress_level;
if (parameters->optimization_level() >= 1)
compress_level = 9;
else
compress_level = 1;
int rc = compress2(reinterpret_cast<Bytef*>(*compressed_data),
compressed_size,
reinterpret_cast<const Bytef*>(uncompressed_data),
uncompressed_size,
compress_level);
if (rc == Z_OK)
return true;
else
{
delete[] *compressed_data;
*compressed_data = NULL;
return false;
}
}
#else // !defined(HAVE_ZLIB_H)
static bool
zlib_compress(const char*, unsigned long, char**, unsigned long*)
{
return false;
}
#endif // !defined(HAVE_ZLIB_H)
// After compressing an output section, we rename it from foo to
// foo.zlib.nnnn, where nnnn is the uncompressed size of the section.
static std::string
zlib_compressed_suffix(unsigned long uncompressed_size)
{
char size_string[64];
snprintf(size_string, sizeof(size_string), "%lu", uncompressed_size);
return std::string(".zlib.") + size_string;
}
// Class Output_compressed_section_data.
// Add an input section. In this case, we just keep track of the sections.
bool
Output_compressed_section_data::do_add_input_section(Relobj* obj,
unsigned int shndx)
{
this->objects_.push_back(Object_entry(obj, shndx));
return true;
}
// Set the final data size of a compressed section. This is where
// we actually compress the section data.
void
Output_compressed_section_data::set_final_data_size()
{
// FIXME: assert that relocations have already been applied.
off_t uncompressed_size = 0;
for (std::vector<Object_entry>::iterator it = this->objects_.begin();
it != this->objects_.end();
++it)
{
it->contents
= it->object->section_contents(it->shndx, &it->length, false);
uncompressed_size += it->length;
}
// (Try to) compress the data.
unsigned long compressed_size;
char* uncompressed_data = new char[uncompressed_size];
off_t pos = 0;
for (std::vector<Object_entry>::const_iterator it = this->objects_.begin();
it != this->objects_.end();
++it)
{
memcpy(uncompressed_data + pos,
reinterpret_cast<const char*>(it->contents),
it->length);
pos += it->length;
}
bool success = false;
if (options_.zlib_compress_debug_sections())
success = zlib_compress(uncompressed_data, uncompressed_size,
&this->data_, &compressed_size);
if (success)
{
delete[] uncompressed_data;
this->set_data_size(compressed_size);
this->new_section_name_ = zlib_compressed_suffix(uncompressed_size);
}
else
{
gold_warning(_("Not compressing section data: zlib error"));
gold_assert(this->data_ == NULL);
this->data_ = uncompressed_data;
this->set_data_size(uncompressed_size);
}
}
// Change the name of the output section to reflect it's compressed.
// The layout routines call into this right before finalizing the
// shstrtab.
const char*
Output_compressed_section_data::do_modified_output_section_name(
const char* name)
{
// This mean we never compressed the data.
if (this->new_section_name_.empty())
return NULL;
this->new_section_name_ = std::string(name) + this->new_section_name_;
return this->new_section_name_.c_str();
}
// Write out a compressed section. If we couldn't compress, we just
// write it out as normal, uncompressed data.
void
Output_compressed_section_data::do_write(Output_file* of)
{
unsigned char* uview = of->get_output_view(this->offset(),
this->data_size());
char* view = reinterpret_cast<char*>(uview);
memcpy(view, this->data_, this->data_size());
of->write_output_view(this->offset(), this->data_size(), uview);
}
// Class Output_compressed_string.
// Add an input section. We don't do anything special here.
template<typename Char_type>
bool
Output_compressed_string<Char_type>::do_add_input_section(Relobj* object,
unsigned int shndx)
{
return Output_merge_string<Char_type>::do_add_input_section(object, shndx);
}
// Set the final data size of a compressed section. This is where
// we actually compress the section data.
template<typename Char_type>
void
Output_compressed_string<Char_type>::set_final_data_size()
{
// First let the superclass finalize all its data, then write it to
// a buffer.
unsigned long uncompressed_size = this->finalize_merged_data();
char* uncompressed_data = new char[uncompressed_size];
this->stringpool_to_buffer(uncompressed_data, uncompressed_size);
// (Try to) compress the data.
unsigned long compressed_size;
if (options_.zlib_compress_debug_sections()
&& zlib_compress(uncompressed_data, uncompressed_size,
&this->compressed_data_, &compressed_size))
{
this->set_data_size(compressed_size);
// Save some memory.
this->clear_stringpool();
// We will be renaming the section to name.zlib.uncompressed_size.
this->new_section_name_ = zlib_compressed_suffix(uncompressed_size);
}
else
{
this->compressed_data_ = NULL;
this->set_data_size(uncompressed_size);
}
delete[] uncompressed_data;
}
// Change the name of the output section to reflect it's compressed.
// The layout routines call into this right before finalizing the
// shstrtab.
template<typename Char_type>
const char*
Output_compressed_string<Char_type>::do_modified_output_section_name(
const char* name)
{
// This mean we never compressed the data
if (this->new_section_name_.empty())
return NULL;
this->new_section_name_ = std::string(name) + this->new_section_name_;
return this->new_section_name_.c_str();
}
// Write out a compressed string section. If we couldn't compress,
// we just write out the normal string section.
template<typename Char_type>
void
Output_compressed_string<Char_type>::do_write(Output_file* of)
{
if (this->compressed_data_ == NULL)
Output_merge_string<Char_type>::do_write(of);
else
{
unsigned char* uview = of->get_output_view(this->offset(),
this->data_size());
char* view = reinterpret_cast<char*>(uview);
memcpy(view, this->compressed_data_, this->data_size());
of->write_output_view(this->offset(), this->data_size(), uview);
}
}
// Instantiate the templates we need.
template
class Output_compressed_string<char>;
template
class Output_compressed_string<uint16_t>;
template
class Output_compressed_string<uint32_t>;
} // End namespace gold.
|