Re: BUG #18899: FreeBSD, assembly by means of GCC with ASAN ends with error: undef reference to backtrace_symbols_fd

PG Bug reporting form <noreply@postgresql.org> writes:
> With ASAN, configtest.c is built without the need for some additional
> libraries, because `backtrace_symbols' defined in
> /usr/local/lib/gcc13/libasan.so.8.

> $ nm -D /usr/local/lib/gcc13/libasan.so.8 | grep backtrace_symbols
> 000000000007e6c0 T __interceptor_backtrace_symbols
> 000000000007e6c0 T backtrace_symbols

Isn't this a flat-out bug/oversight in libasan?  It's hard to believe
that they have a reason for overriding backtrace_symbols that would
not also apply to backtrace_symbols_fd.  Nor that it's a good idea
to risk applications seeing different behaviors from those functions.

> This corrects the problem for me:

> -AC_SEARCH_LIBS(backtrace_symbols, execinfo)
> +AC_SEARCH_LIBS(backtrace_symbols_fd, execinfo)

I do not love this fix.  It's certainly arguable that we shouldn't
assume that backtrace_symbols_fd is available just because
backtrace_symbols is, but the reverse assumption is not much better.
If we were to do anything about this, I think what it ought to be
is to make separate configure probes for the two functions and then
have assert.c say "#ifdef HAVE_BACKTRACE_SYMBOLS_FD".  But on the
whole I think this is libasan's problem not ours.  While you're
waiting for them to fix it you could just manually add
LDFLAGS=-lexecinfo in ASAN builds.

            regards, tom lane