c992dd8a9b
Support decompressing --compress-debug-sections=zstd. * configure.ac: Check for zstd library and --compress-debug-sections=zstd linker option. * Makefile.am (zstdtest_*): New targets. (zstdtest_alloc_*, ctestzstd_*): New targets. (BUILDTESTS): Add zstdtest, zstdtest_alloc, ctestzstd as appropriate. * elf.c (ELFCOMPRESS_ZSTD): Define. (elf_fetch_bits): Rename from elf_zlib_fetch. Update uses. (elf_fetch_bits_backward): New static function. (ZLIB_HUFFMAN_*): Rename from HUFFMAN_*. Update uses. (ZLIB_TABLE_*): Rename from ZDEBUG_TABLE_*. Update uses. (ZSTD_TABLE_*): Define. (struct elf_zstd_fse_entry): Define. (elf_zstd_read_fse): New static function. (elf_zstd_build_fse): Likewise. (lit): Define if BACKTRACE_GENERATE_ZSTD_FSE_TABLES. (match, offset, next, print_table, main): Likewise. (elf_zstd_lit_table): New static const array. (elf_zstd_match_table, elf_zstd_offset_table): Likewise. (elf_zstd_read_huff): New static function. (struct elf_zstd_seq_decode): Define. (elf_zstd_unpack_seq_decode): New static function. (ZSTD_LIT_*): Define. (struct elf_zstd_literals): Define. (elf_zstd_literal_output): New static function. (ZSTD_LITERAL_LENGTH_BASELINE_OFFSET): Define. (elf_zstd_literal_length_baseline): New static const array. (elf_zstd_literal_length_bits): Likewise. (ZSTD_MATCH_LENGTH_BASELINE_OFFSET): Define. (elf_zstd_match_length_baseline): New static const array. (elf_zstd_match_length_bits): Likewise. (elf_zstd_decompress): New static function. (ZDEBUG_TABLE_SIZE): New definition. (elf_uncompress_chdr): Support ELF_COMPRESS_ZSTD. (backtrace_uncompress_zstd): New function. (elf_add): Use ZLIB_TABLE_SIZE for zlib-gnu sections. * internal.h (backtrace_uncompress_zstd): Declare. * zstdtest.c: New file. * configure, config.h.in, Makefile.in: Regenerate.
libbacktrace
A C library that may be linked into a C/C++ program to produce symbolic backtraces
Initially written by Ian Lance Taylor iant@golang.org.
This is version 1.0. It is likely that this will always be version 1.0.
The libbacktrace library may be linked into a program or library and used to produce symbolic backtraces. Sample uses would be to print a detailed backtrace when an error occurs or to gather detailed profiling information. In general the functions provided by this library are async-signal-safe, meaning that they may be safely called from a signal handler.
The libbacktrace library is provided under a BSD license. See the source files for the exact license text.
The public functions are declared and documented in the header file backtrace.h, which should be #include'd by a user of the library.
Building libbacktrace will generate a file backtrace-supported.h, which a user of the library may use to determine whether backtraces will work. See the source file backtrace-supported.h.in for the macros that it defines.
As of October 2020, libbacktrace supports ELF, PE/COFF, Mach-O, and XCOFF executables with DWARF debugging information. In other words, it supports GNU/Linux, *BSD, macOS, Windows, and AIX. The library is written to make it straightforward to add support for other object file and debugging formats.
The library relies on the C++ unwind API defined at https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html This API is provided by GCC and clang.