| // compressed_output.cc -- manage compressed debug sections for gold |
| |
| // Copyright (C) 2007-2021 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" |
| #include <zlib.h> |
| #include "parameters.h" |
| #include "options.h" |
| #include "compressed_output.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. |
| // 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(int header_size, |
| const unsigned char* uncompressed_data, |
| unsigned long uncompressed_size, |
| unsigned char** compressed_data, |
| unsigned long* compressed_size) |
| { |
| *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) |
| { |
| *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; |
| } |
| |
| // 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, |
| int size, |
| bool big_endian, |
| elfcpp::Elf_Xword sh_flags) |
| { |
| if ((sh_flags & elfcpp::SHF_COMPRESSED) != 0) |
| { |
| unsigned int compression_header_size; |
| if (size == 32) |
| { |
| compression_header_size = elfcpp::Elf_sizes<32>::chdr_size; |
| if (big_endian) |
| { |
| elfcpp::Chdr<32, true> chdr(compressed_data); |
| if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB) |
| return false; |
| } |
| else |
| { |
| elfcpp::Chdr<32, false> chdr(compressed_data); |
| if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB) |
| return false; |
| } |
| } |
| else if (size == 64) |
| { |
| compression_header_size = elfcpp::Elf_sizes<64>::chdr_size; |
| if (big_endian) |
| { |
| elfcpp::Chdr<64, true> chdr(compressed_data); |
| if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB) |
| return false; |
| } |
| else |
| { |
| elfcpp::Chdr<64, false> chdr(compressed_data); |
| if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB) |
| return false; |
| } |
| } |
| else |
| gold_unreachable(); |
| |
| return zlib_decompress(compressed_data + compression_header_size, |
| compressed_size - compression_header_size, |
| uncompressed_data, |
| 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; |
| enum { none, gnu_zlib, gabi_zlib } compress; |
| int compression_header_size = 12; |
| const int size = parameters->target().get_size(); |
| if (strcmp(this->options_->compress_debug_sections(), "zlib-gnu") == 0) |
| compress = gnu_zlib; |
| else if (strcmp(this->options_->compress_debug_sections(), "zlib-gabi") == 0 |
| || strcmp(this->options_->compress_debug_sections(), "zlib") == 0) |
| { |
| compress = gabi_zlib; |
| if (size == 32) |
| compression_header_size = elfcpp::Elf_sizes<32>::chdr_size; |
| else if (size == 64) |
| compression_header_size = elfcpp::Elf_sizes<64>::chdr_size; |
| else |
| gold_unreachable(); |
| } |
| else |
| compress = none; |
| if (compress != none) |
| success = zlib_compress(compression_header_size, uncompressed_data, |
| uncompressed_size, &this->data_, |
| &compressed_size); |
| if (success) |
| { |
| elfcpp::Elf_Xword flags = this->flags(); |
| if (compress == gabi_zlib) |
| { |
| // Set the SHF_COMPRESSED bit. |
| flags |= elfcpp::SHF_COMPRESSED; |
| const bool is_big_endian = parameters->target().is_big_endian(); |
| uint64_t addralign = this->addralign(); |
| if (size == 32) |
| { |
| if (is_big_endian) |
| { |
| elfcpp::Chdr_write<32, true> chdr(this->data_); |
| chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB); |
| chdr.put_ch_size(uncompressed_size); |
| chdr.put_ch_addralign(addralign); |
| } |
| else |
| { |
| elfcpp::Chdr_write<32, false> chdr(this->data_); |
| chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB); |
| chdr.put_ch_size(uncompressed_size); |
| chdr.put_ch_addralign(addralign); |
| } |
| } |
| else if (size == 64) |
| { |
| if (is_big_endian) |
| { |
| elfcpp::Chdr_write<64, true> chdr(this->data_); |
| chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB); |
| chdr.put_ch_size(uncompressed_size); |
| chdr.put_ch_addralign(addralign); |
| // Clear the reserved field. |
| chdr.put_ch_reserved(0); |
| } |
| else |
| { |
| elfcpp::Chdr_write<64, false> chdr(this->data_); |
| chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB); |
| chdr.put_ch_size(uncompressed_size); |
| chdr.put_ch_addralign(addralign); |
| // Clear the reserved field. |
| chdr.put_ch_reserved(0); |
| } |
| } |
| else |
| gold_unreachable(); |
| } |
| else |
| { |
| // Write out the zlib header. |
| memcpy(this->data_, "ZLIB", 4); |
| elfcpp::Swap_unaligned<64, true>::writeval(this->data_ + 4, |
| uncompressed_size); |
| // 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_flags(flags); |
| 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. |