mirror_zfs/config/user-libunwind.m4
Rob Norris 051460b8b2 libspl/assert: use libunwind for backtrace when available
libunwind seems to do a better job of resolving a symbols than
backtrace(), and is also useful on platforms that don't have backtrace()
(eg musl). If it's available, use it.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/
Closes #16140
2024-05-01 10:52:05 -07:00

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dnl
dnl Checks for libunwind, which usually does a better job than backtrace() when
dnl resolving symbols in the stack backtrace. Newer versions have support for
dnl getting info about the object file the function came from, so we look for
dnl that too and use it if found.
dnl
AC_DEFUN([ZFS_AC_CONFIG_USER_LIBUNWIND], [
AC_ARG_WITH([libunwind],
AS_HELP_STRING([--with-libunwind],
[use libunwind for backtraces in userspace assertions]),
[],
[with_libunwind=auto])
AS_IF([test "x$with_libunwind" != "xno"], [
ZFS_AC_FIND_SYSTEM_LIBRARY(LIBUNWIND, [libunwind], [libunwind.h], [], [unwind], [], [
dnl unw_get_elf_filename() is sometimes a macro, other
dnl times a proper symbol, so we can't just do a link
dnl check; we need to include the header properly.
AX_SAVE_FLAGS
CFLAGS="$CFLAGS $LIBUNWIND_CFLAGS"
LIBS="$LIBS $LIBUNWIND_LIBS"
AC_MSG_CHECKING([for unw_get_elf_filename in libunwind])
AC_LINK_IFELSE([
AC_LANG_PROGRAM([
#define UNW_LOCAL_ONLY
#include <libunwind.h>
], [
unw_get_elf_filename(0, 0, 0, 0);
])
], [
AC_MSG_RESULT([yes])
AC_DEFINE(HAVE_LIBUNWIND_ELF, 1,
[libunwind has unw_get_elf_filename])
], [
AC_MSG_RESULT([no])
])
AX_RESTORE_FLAGS
], [
AS_IF([test "x$with_libunwind" = "xyes"], [
AC_MSG_FAILURE([--with-libunwind was given, but libunwind is not available, try installing libunwind-devel])
])
])
])
])