1 // compressed_output.cc -- manage compressed output sections for gold
3 // Copyright 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.
29 #include "parameters.h"
31 #include "compressed_output.h"
36 // Compress UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns true
37 // if it successfully compressed, false if it failed for any reason
38 // (including not having zlib support in the library). If it returns
39 // true, it allocates memory for the compressed data using new, and
40 // sets *COMPRESSED_DATA and *COMPRESSED_SIZE to appropriate values.
45 zlib_compress(const char* uncompressed_data, unsigned long uncompressed_size,
46 char** compressed_data, unsigned long* compressed_size)
48 *compressed_size = uncompressed_size + uncompressed_size / 1000 + 128;
49 *compressed_data = new char[*compressed_size];
52 if (parameters->options().optimize() >= 1)
57 int rc = compress2(reinterpret_cast<Bytef*>(*compressed_data),
59 reinterpret_cast<const Bytef*>(uncompressed_data),
66 delete[] *compressed_data;
67 *compressed_data = NULL;
72 #else // !defined(HAVE_ZLIB_H)
75 zlib_compress(const char*, unsigned long, char**, unsigned long*)
80 #endif // !defined(HAVE_ZLIB_H)
82 // After compressing an output section, we rename it from foo to
83 // foo.zlib.nnnn, where nnnn is the uncompressed size of the section.
86 zlib_compressed_suffix(unsigned long uncompressed_size)
89 snprintf(size_string, sizeof(size_string), "%lu", uncompressed_size);
90 return std::string(".zlib.") + size_string;
93 // Class Output_compressed_section.
95 // Set the final data size of a compressed section. This is where
96 // we actually compress the section data.
99 Output_compressed_section::set_final_data_size()
101 off_t uncompressed_size = this->postprocessing_buffer_size();
103 // (Try to) compress the data.
104 unsigned long compressed_size;
105 unsigned char* u_uncompressed_data = this->postprocessing_buffer();
106 char* uncompressed_data = reinterpret_cast<char*>(u_uncompressed_data);
108 // At this point the contents of all regular input sections will
109 // have been copied into the postprocessing buffer, and relocations
110 // will have been applied. Now we need to copy in the contents of
111 // anything other than a regular input section.
112 this->write_to_postprocessing_buffer();
114 bool success = false;
115 if (strcmp(this->options_->compress_debug_sections(), "zlib") == 0)
116 success = zlib_compress(uncompressed_data, uncompressed_size,
117 &this->data_, &compressed_size);
120 std::string suffix(zlib_compressed_suffix(uncompressed_size));
121 this->new_section_name_ = std::string(this->name()) + suffix;
122 this->set_name(this->new_section_name_.c_str());
123 this->set_data_size(compressed_size);
127 gold_warning(_("not compressing section data: zlib error"));
128 gold_assert(this->data_ == NULL);
129 this->set_data_size(uncompressed_size);
133 // Write out a compressed section. If we couldn't compress, we just
134 // write it out as normal, uncompressed data.
137 Output_compressed_section::do_write(Output_file* of)
139 off_t offset = this->offset();
140 off_t data_size = this->data_size();
141 unsigned char* view = of->get_output_view(offset, data_size);
142 if (this->data_ == NULL)
143 memcpy(view, this->postprocessing_buffer(), data_size);
145 memcpy(view, this->data_, data_size);
146 of->write_output_view(offset, data_size, view);
149 } // End namespace gold.