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9a0910c3 ILT |
1 | // compressed_output.cc -- manage compressed output sections for gold |
2 | ||
3 | // Copyright 2007 Free Software Foundation, Inc. | |
4 | // Written by Ian Lance Taylor <iant@google.com>. | |
5 | ||
6 | // This file is part of gold. | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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. | |
22 | ||
23 | #include "gold.h" | |
24 | ||
25 | #ifdef HAVE_ZLIB_H | |
26 | #include <zlib.h> | |
27 | #endif | |
28 | ||
29 | #include "compressed_output.h" | |
30 | #include "parameters.h" | |
31 | ||
32 | namespace gold | |
33 | { | |
34 | ||
35 | // Compress UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns true | |
36 | // if it successfully compressed, false if it failed for any reason | |
37 | // (including not having zlib support in the library). If it returns | |
38 | // true, it allocates memory for the compressed data using new, and | |
39 | // sets *COMPRESSED_DATA and *COMPRESSED_SIZE to appropriate values. | |
40 | ||
41 | static bool | |
42 | zlib_compress(const char* uncompressed_data, unsigned long uncompressed_size, | |
43 | char** compressed_data, unsigned long* compressed_size) | |
44 | { | |
45 | #ifndef HAVE_ZLIB_H | |
46 | return false; | |
47 | #else | |
48 | *compressed_size = uncompressed_size + uncompressed_size / 1000 + 128; | |
49 | *compressed_data = new char[*compressed_size]; | |
50 | ||
51 | int compress_level; | |
52 | if (parameters->optimization_level() >= 1) | |
53 | compress_level = 9; | |
54 | else | |
55 | compress_level = 1; | |
56 | ||
57 | int rc = compress2(reinterpret_cast<Bytef*>(*compressed_data), | |
58 | compressed_size, | |
59 | reinterpret_cast<const Bytef*>(uncompressed_data), | |
60 | uncompressed_size, | |
61 | compress_level); | |
62 | if (rc == Z_OK) | |
63 | return true; | |
64 | else | |
65 | { | |
66 | delete[] *compressed_data; | |
67 | *compressed_data = NULL; | |
68 | return false; | |
69 | } | |
70 | #endif // #ifdef HAVE_ZLIB_H | |
71 | } | |
72 | ||
73 | // After compressing an output section, we rename it from foo to | |
74 | // foo.zlib.nnnn, where nnnn is the uncompressed size of the section. | |
75 | ||
76 | static std::string | |
77 | zlib_compressed_suffix(unsigned long uncompressed_size) | |
78 | { | |
79 | char size_string[64]; | |
80 | snprintf(size_string, sizeof(size_string), "%lu", uncompressed_size); | |
81 | return std::string(".zlib.") + size_string; | |
82 | } | |
83 | ||
84 | // Class Output_compressed_section_data. | |
85 | ||
86 | // Add an input section. In this case, we just keep track of the sections. | |
87 | ||
88 | bool | |
89 | Output_compressed_section_data::do_add_input_section(Relobj* obj, | |
90 | unsigned int shndx) | |
91 | { | |
92 | this->objects_.push_back(Object_entry(obj, shndx)); | |
93 | return true; | |
94 | } | |
95 | ||
96 | // Set the final data size of a compressed section. This is where | |
97 | // we actually compress the section data. | |
98 | ||
99 | void | |
100 | Output_compressed_section_data::set_final_data_size() | |
101 | { | |
102 | // FIXME: assert that relocations have already been applied. | |
103 | ||
104 | off_t uncompressed_size = 0; | |
105 | for (std::vector<Object_entry>::iterator it = this->objects_.begin(); | |
106 | it != this->objects_.end(); | |
107 | ++it) | |
108 | { | |
109 | it->contents | |
110 | = it->object->section_contents(it->shndx, &it->length, false); | |
111 | uncompressed_size += it->length; | |
112 | } | |
113 | ||
114 | // (Try to) compress the data. | |
115 | unsigned long compressed_size; | |
116 | char* uncompressed_data = new char[uncompressed_size]; | |
117 | off_t pos = 0; | |
118 | for (std::vector<Object_entry>::const_iterator it = this->objects_.begin(); | |
119 | it != this->objects_.end(); | |
120 | ++it) | |
121 | { | |
122 | memcpy(uncompressed_data + pos, | |
123 | reinterpret_cast<const char*>(it->contents), | |
124 | it->length); | |
125 | pos += it->length; | |
126 | } | |
127 | ||
128 | bool success = false; | |
129 | if (options_.zlib_compress_debug_sections()) | |
130 | success = zlib_compress(uncompressed_data, uncompressed_size, | |
131 | &this->data_, &compressed_size); | |
132 | if (success) | |
133 | { | |
134 | delete[] uncompressed_data; | |
135 | this->set_data_size(compressed_size); | |
136 | this->new_section_name_ = zlib_compressed_suffix(uncompressed_size); | |
137 | } | |
138 | else | |
139 | { | |
140 | gold_warning(_("Not compressing section data: zlib error")); | |
141 | gold_assert(this->data_ == NULL); | |
142 | this->data_ = uncompressed_data; | |
143 | this->set_data_size(uncompressed_size); | |
144 | } | |
145 | } | |
146 | ||
147 | // Change the name of the output section to reflect it's compressed. | |
148 | // The layout routines call into this right before finalizing the | |
149 | // shstrtab. | |
150 | ||
151 | const char* | |
152 | Output_compressed_section_data::do_modified_output_section_name( | |
153 | const char* name) | |
154 | { | |
155 | // This mean we never compressed the data. | |
156 | if (this->new_section_name_.empty()) | |
157 | return NULL; | |
158 | this->new_section_name_ = std::string(name) + this->new_section_name_; | |
159 | return this->new_section_name_.c_str(); | |
160 | } | |
161 | ||
162 | // Write out a compressed section. If we couldn't compress, we just | |
163 | // write it out as normal, uncompressed data. | |
164 | ||
165 | void | |
166 | Output_compressed_section_data::do_write(Output_file* of) | |
167 | { | |
168 | unsigned char* uview = of->get_output_view(this->offset(), | |
169 | this->data_size()); | |
170 | char* view = reinterpret_cast<char*>(uview); | |
171 | memcpy(view, this->data_, this->data_size()); | |
172 | of->write_output_view(this->offset(), this->data_size(), uview); | |
173 | } | |
174 | ||
175 | // Class Output_compressed_string. | |
176 | ||
177 | // Add an input section. We don't do anything special here. | |
178 | ||
179 | template<typename Char_type> | |
180 | bool | |
181 | Output_compressed_string<Char_type>::do_add_input_section(Relobj* object, | |
182 | unsigned int shndx) | |
183 | { | |
184 | return Output_merge_string<Char_type>::do_add_input_section(object, shndx); | |
185 | } | |
186 | ||
187 | // Set the final data size of a compressed section. This is where | |
188 | // we actually compress the section data. | |
189 | ||
190 | template<typename Char_type> | |
191 | void | |
192 | Output_compressed_string<Char_type>::set_final_data_size() | |
193 | { | |
194 | // First let the superclass finalize all its data, then write it to | |
195 | // a buffer. | |
196 | unsigned long uncompressed_size = this->finalize_merged_data(); | |
197 | char* uncompressed_data = new char[uncompressed_size]; | |
198 | this->stringpool_to_buffer(uncompressed_data, uncompressed_size); | |
199 | ||
200 | // (Try to) compress the data. | |
201 | unsigned long compressed_size; | |
202 | if (options_.zlib_compress_debug_sections() | |
203 | && zlib_compress(uncompressed_data, uncompressed_size, | |
204 | &this->compressed_data_, &compressed_size)) | |
205 | { | |
206 | this->set_data_size(compressed_size); | |
207 | // Save some memory. | |
208 | this->clear_stringpool(); | |
209 | // We will be renaming the section to name.zlib.uncompressed_size. | |
210 | this->new_section_name_ = zlib_compressed_suffix(uncompressed_size); | |
211 | } | |
212 | else | |
213 | { | |
214 | this->compressed_data_ = NULL; | |
215 | this->set_data_size(uncompressed_size); | |
216 | } | |
217 | ||
218 | delete[] uncompressed_data; | |
219 | } | |
220 | ||
221 | // Change the name of the output section to reflect it's compressed. | |
222 | // The layout routines call into this right before finalizing the | |
223 | // shstrtab. | |
224 | ||
225 | template<typename Char_type> | |
226 | const char* | |
227 | Output_compressed_string<Char_type>::do_modified_output_section_name( | |
228 | const char* name) | |
229 | { | |
230 | // This mean we never compressed the data | |
231 | if (this->new_section_name_.empty()) | |
232 | return NULL; | |
233 | this->new_section_name_ = std::string(name) + this->new_section_name_; | |
234 | return this->new_section_name_.c_str(); | |
235 | } | |
236 | ||
237 | // Write out a compressed string section. If we couldn't compress, | |
238 | // we just write out the normal string section. | |
239 | ||
240 | template<typename Char_type> | |
241 | void | |
242 | Output_compressed_string<Char_type>::do_write(Output_file* of) | |
243 | { | |
244 | if (this->compressed_data_ == NULL) | |
245 | Output_merge_string<Char_type>::do_write(of); | |
246 | else | |
247 | { | |
248 | unsigned char* uview = of->get_output_view(this->offset(), | |
249 | this->data_size()); | |
250 | char* view = reinterpret_cast<char*>(uview); | |
251 | memcpy(view, this->compressed_data_, this->data_size()); | |
252 | of->write_output_view(this->offset(), this->data_size(), uview); | |
253 | } | |
254 | } | |
255 | ||
256 | // Instantiate the templates we need. | |
257 | ||
258 | template | |
259 | class Output_compressed_string<char>; | |
260 | ||
261 | template | |
262 | class Output_compressed_string<uint16_t>; | |
263 | ||
264 | template | |
265 | class Output_compressed_string<uint32_t>; | |
266 | ||
267 | } // End namespace gold. |