On Sat, Mar 3, 2012 at 00:35, FX fxcoud...@gmail.com wrote:
I'll offer my first patch to the new 4.8 trunk. I noticed that the
-fbacktrace option and the GFORTRAN_ERROR_BACKTRACE environment variable are
somewhat inconsistently handled. Currently, the environment variabled doesn't
actually override the compilation option, as it should. So, I set to change
that (checking both options.backtrace and compile_options.backtrace instead
of only the latter) when I realized that we could improve this further by
moving the checking code: it is currently located in the set_options()
function, which is called from the main Fortran routine (call generated by
the front-end). This means that it's not triggered if the main program is C.
Full disclosure: I removed the function maybe_find_addr2line() because it's
not needed anymore now the code was regrouped. However, I'll note that I
don't understand why it was useful before, and that I think the comment on
top of it was wrong (variable options could be seen in the function, it was
just shadowed by the local function argument!). Thus, while I was at it, I
renamed the options argument to set_options(), just to make sure we didn't
have a problem of this sort in the future.
I added it because, as you say, the argument options in
set_options() prevented access to the global variable options, and I
was lazy and considered a new function faster than renaming the
The change was bootstrapped and regtested on x86_64-apple-darwin11, but is an
area not covered by the testsuite. I have manually checked that running
various types of abort, both in a pure Fortran code and a mixed C/Fortran
(with C main), with all combinations -fno-backtrace/GFORTRAN_ERROR_BACKTRACE,
behaved as expected.
I don't think it will work if you have a C main program which then
calls _gfortran_set_options() to enable backtracing per the
mixed-language programming chapter in the manual. You probably need to
move the setup code to a separate function which is called both from
init and set_options.
Also, in the patch as it stands now, you could make find_addr2line
static and remove the prototype from libgfortran.h. That being said,
I'd recommend moving both find_addr2line and the signal handler setup
code to backtrace.c, and then do a bit of janitorial work checking
which functions and variables can be made static.