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Diffstat (limited to 'binutils-2.25/gold/compressed_output.cc')
| -rw-r--r-- | binutils-2.25/gold/compressed_output.cc | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/binutils-2.25/gold/compressed_output.cc b/binutils-2.25/gold/compressed_output.cc new file mode 100644 index 0000000..9c7c7dd --- /dev/null +++ b/binutils-2.25/gold/compressed_output.cc @@ -0,0 +1,247 @@ +// compressed_output.cc -- manage compressed debug sections for gold + +// Copyright 2007, 2008, 2010 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 "parameters.h" +#include "options.h" +#include "compressed_output.h" + +namespace gold +{ + +#ifdef HAVE_ZLIB_H + +// 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. +// It also writes a header before COMPRESSED_DATA: 4 bytes saying +// "ZLIB", and 8 bytes indicating the uncompressed size, in big-endian +// order. + +static bool +zlib_compress(const unsigned char* uncompressed_data, + unsigned long uncompressed_size, + unsigned char** compressed_data, + unsigned long* compressed_size) +{ + const int header_size = 12; + *compressed_size = uncompressed_size + uncompressed_size / 1000 + 128; + *compressed_data = new unsigned char[*compressed_size + header_size]; + + int compress_level; + if (parameters->options().optimize() >= 1) + compress_level = 9; + else + compress_level = 1; + + int rc = compress2(reinterpret_cast<Bytef*>(*compressed_data) + header_size, + compressed_size, + reinterpret_cast<const Bytef*>(uncompressed_data), + uncompressed_size, + compress_level); + if (rc == Z_OK) + { + memcpy(*compressed_data, "ZLIB", 4); + elfcpp::Swap_unaligned<64, true>::writeval(*compressed_data + 4, + uncompressed_size); + *compressed_size += header_size; + return true; + } + else + { + delete[] *compressed_data; + *compressed_data = NULL; + return false; + } +} + +// Decompress COMPRESSED_DATA of size COMPRESSED_SIZE, into a buffer +// UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns TRUE if it +// decompressed successfully, false if it failed. The buffer, of +// appropriate size, is provided by the caller, and is typically part +// of the memory-mapped output file. + +static bool +zlib_decompress(const unsigned char* compressed_data, + unsigned long compressed_size, + unsigned char* uncompressed_data, + unsigned long uncompressed_size) +{ + z_stream strm; + int rc; + + /* It is possible the section consists of several compressed + buffers concatenated together, so we uncompress in a loop. */ + strm.zalloc = NULL; + strm.zfree = NULL; + strm.opaque = NULL; + strm.avail_in = compressed_size; + strm.next_in = const_cast<Bytef*>(compressed_data); + strm.avail_out = uncompressed_size; + + rc = inflateInit(&strm); + while (strm.avail_in > 0) + { + if (rc != Z_OK) + return false; + strm.next_out = ((Bytef*) uncompressed_data + + (uncompressed_size - strm.avail_out)); + rc = inflate(&strm, Z_FINISH); + if (rc != Z_STREAM_END) + return false; + rc = inflateReset(&strm); + } + rc = inflateEnd(&strm); + if (rc != Z_OK || strm.avail_out != 0) + return false; + + return true; +} + +#else // !defined(HAVE_ZLIB_H) + +static bool +zlib_compress(const unsigned char*, unsigned long, + unsigned char**, unsigned long*) +{ + return false; +} + +static bool +zlib_decompress(const unsigned char*, unsigned long, + unsigned char*, unsigned long) +{ + return false; +} + +#endif // !defined(HAVE_ZLIB_H) + +// Read the compression header of a compressed debug section and return +// the uncompressed size. + +uint64_t +get_uncompressed_size(const unsigned char* compressed_data, + section_size_type compressed_size) +{ + const unsigned int zlib_header_size = 12; + + /* Verify the compression header. Currently, we support only zlib + compression, so it should be "ZLIB" followed by the uncompressed + section size, 8 bytes in big-endian order. */ + if (compressed_size >= zlib_header_size + && strncmp(reinterpret_cast<const char*>(compressed_data), + "ZLIB", 4) == 0) + return elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4); + return -1ULL; +} + +// Decompress a compressed debug section directly into the output file. + +bool +decompress_input_section(const unsigned char* compressed_data, + unsigned long compressed_size, + unsigned char* uncompressed_data, + unsigned long uncompressed_size) +{ + const unsigned int zlib_header_size = 12; + + /* Verify the compression header. Currently, we support only zlib + compression, so it should be "ZLIB" followed by the uncompressed + section size, 8 bytes in big-endian order. */ + if (compressed_size >= zlib_header_size + && strncmp(reinterpret_cast<const char*>(compressed_data), + "ZLIB", 4) == 0) + { + unsigned long uncompressed_size_check = + elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4); + gold_assert(uncompressed_size_check == uncompressed_size); + return zlib_decompress(compressed_data + zlib_header_size, + compressed_size - zlib_header_size, + uncompressed_data, + uncompressed_size); + } + return false; +} + +// Class Output_compressed_section. + +// Set the final data size of a compressed section. This is where +// we actually compress the section data. + +void +Output_compressed_section::set_final_data_size() +{ + off_t uncompressed_size = this->postprocessing_buffer_size(); + + // (Try to) compress the data. + unsigned long compressed_size; + unsigned char* uncompressed_data = this->postprocessing_buffer(); + + // At this point the contents of all regular input sections will + // have been copied into the postprocessing buffer, and relocations + // will have been applied. Now we need to copy in the contents of + // anything other than a regular input section. + this->write_to_postprocessing_buffer(); + + bool success = false; + if (strcmp(this->options_->compress_debug_sections(), "zlib") == 0) + success = zlib_compress(uncompressed_data, uncompressed_size, + &this->data_, &compressed_size); + if (success) + { + // This converts .debug_foo to .zdebug_foo + this->new_section_name_ = std::string(".z") + (this->name() + 1); + this->set_name(this->new_section_name_.c_str()); + this->set_data_size(compressed_size); + } + else + { + gold_warning(_("not compressing section data: zlib error")); + gold_assert(this->data_ == NULL); + this->set_data_size(uncompressed_size); + } +} + +// Write out a compressed section. If we couldn't compress, we just +// write it out as normal, uncompressed data. + +void +Output_compressed_section::do_write(Output_file* of) +{ + off_t offset = this->offset(); + off_t data_size = this->data_size(); + unsigned char* view = of->get_output_view(offset, data_size); + if (this->data_ == NULL) + memcpy(view, this->postprocessing_buffer(), data_size); + else + memcpy(view, this->data_, data_size); + of->write_output_view(offset, data_size, view); +} + +} // End namespace gold. |