bug#42761: 28.0.50; [feature/native-comp] allow customizing command line/driver options?

[Andrea Corallo via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Andreas Fuchs <asf@boinkor.net> writes:

> On Sun, Aug 9, 2020 at 3:58 AM Andrea Corallo <akrl@sdf.org> wrote:
>> From the patch:
>> > + #ifdef LIBGCCJIT_HAVE_gcc_jit_context_add_command_line_option
>> > + DEF_DLL_FN (void, gcc_jit_context_add_driver_option,
>> > +             (gcc_jit_context *ctxt, const char *optname));
>> > + #endif
>> [...]
>> > + #ifdef LIBGCCJIT_HAVE_gcc_jit_context_add_command_line_option
>> > +   LOAD_DLL_FN (library, gcc_jit_context_add_driver_option);
>> > + #endif
>>
>> The above should not be ifdef'd as they allow the function to be
> used
>> only if present in the library in use at runtime on Windows
> systems.
>>
>> Unfortunatelly we do not have such system for Linux where the
> decision
>> to include the call is done at compile time.  So unless we
> implement
>> that too also the call site has to be a little changed to handle
> this.
>>
>> Please have a look for that into in Fcomp_libgccjit_version where
> we use
>> gcc_jit_version_*.  These are the only "optional" libgccjit entry
> point
>> we used so far.
>
> Ah, I misread the #ifdef condition above those. Makes sense, I've
> adjusted
> the branch and added one more commit that should ensure we pass the
> `comp-native-driver-options' to async compilation child processes
> correctly.
>
> This patch builds on my system, builds on darwin under nix (with
> some 
> additional changes to emit "-L" library path entries), and
> asynchronously 
> compiles code, too!

Sounds great.

Some small notes:

> + static void
> + add_driver_options ()
> + {
> +   Lisp_Object options = Fsymbol_value (Qcomp_native_driver_options);
> + 
> + #ifdef LIBGCCJIT_HAVE_gcc_jit_context_add_command_line_option

I think here would be better to use something like

#if defined (LIBGCCJIT_HAVE_gcc_jit_context_add_driver_option) || defined (WINDOWSNT)

plus the pragma to cleanup the warning as we do in Fcomp_libgccjit_version.

> +   while (CONSP (options))
> +     {
> +       gcc_jit_context_add_driver_option (comp.ctxt, SSDATA (XCAR (options)));
> +       options = XCDR (options);
> +     }
> + #else
> +   if (CONSP (options))
> +     {
> +       xsignal1 (Qnative_compiler_error,
> +                 build_string ("Customizing native compiler options via `comp-native-driver-options' is only available on libgccjit version 9 and above."));

We should break this line to be max 80 columns wide.

> +     }
> + #endif
> + }

[...]

With those changes looks good to me once the paperwork is completed.

Thanks!

  Andrea
  
-- 
akrl@sdf.org