Ian Lance Taylor
6f8310e238
Based on patch from Andi Kleen. * backtrace.h (backtrace_create_state): Rewrite comment to change threaded parameter to flags. (backtrace_full_callback, backtrace_syminfo_callback): Document behavior change if moredata flag is set. (struct backtrace_moredata): Define. * backtrace-supported.h.in (BACKTRACE_SUPPORTS_MOREDATA): Define. * internal.h (struct backtrace_state): Add moredata field. (BACKTRACE_MOREDATA_VERSION): Define. * state.c (backtrace_create_state): Change threaded parameter to flags. Set state moredata field based on flags. * dwarf.c (struct line): Add disc field. (struct function): Add caller_disc field. (call_callback): New static function. (add_line): Add disc parameter. Change all callers. Store disc in new line value. (read_line_program): Track discriminator value. (read_line_info): Initialize disc field in final line entry. (read_function_entry): Handle DW_AT_GNU_discriminator. (report_inlined_functions): Add disc parameter. Change all callers. Call call_callback rather than calling callback directly. (dwarf_lookup_pc): Handle inlined discriminators. Call call_callback rather than calling callback directly. (dwarf_fileline): Call call_callback rather than calling callback directly. * elf.c (elf_syminfo): Pass moredata if requested. * macho.c (macho_syminfo): Likewise. * pecoff.c (coff_syminfo): Likewise. * xcoff.c (xcoff_syminfo): Likewise. (xcoff_lookup_pc): Likewise. * backtrace.c: #include <string.h>. (unwind): Pass moredata if requested. * unknown.c: #include <string.h>. (unknown_fileline): Pass moredata if requested. * fileline.c (backtrace_syminfo_to_full_callback): Add comment about moredata. * mdtest.c: New test file. * Makefile.am (mdtest_SOURCES): Define. (mdtest_CFLAGS, mdtest_LDFLAGS, mdtest_LDADD): Define. (BUILDTESTS): Add mdtest. * 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.
That said, on systems that use dl_iterate_phdr, such as GNU/Linux,
the first call to a libbacktrace function will call dl_iterate_phdr,
which is not in general async-signal-safe. Therefore, programs
that call libbacktrace from a signal handler should ensure that they
make an initial call from outside of a signal handler.
Similar considerations apply when arranging to call libbacktrace
from within malloc; dl_iterate_phdr can also call malloc,
so make an initial call to a libbacktrace function outside of
malloc before trying to call libbacktrace functions within malloc.
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 July 2024, 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.