[RFC PATCH] Emit DW_LANG_Fortran{03,08}

[Tobias Burnus]

Jakub Jelinek wrote:
> DW_LANG_Fortran03 and DW_LANG_Fortran08 DW_AT_language values were recently
> accepted into DWARF5.  This patch changes GCC to handle those similarly to
> how e.g. the -std=c++11, -std=c++14 or -std=c11 are handled.

For completeness: gfortran currently produces "GNU Fortran" and 
DW_LANG_Fortran95; GCC itself also handles ...Fortran77 and 
...Fortran90, but those are not produced with gfortran.

With the patch, it produces for -gdwarf-2/3/4 (4 is default) or 
"-gdwarf-5 -std=f95" the same as above. For -std=f2003 -gdwarf-5, it 
yields "GNU Fortran2003" and DW_LANG_Fortran2003. And for -gdwarf-5 and 
the rest of -std= (f2008, f2008ts, gnu, legacy), it produces "GNU 
Fortran2008" and DW_LANG_Fortran2008.

(In principle, they could have prepared for the future and added Fortran 
2015 as well.)


Regarding the change: it is fine with me. (However, I wonder how much 
will break, once the "|| !dwarf_strict" is enabled, knowing that 
compilers are often more frequently updated as debuggers, valgrind and 
similar programs. On the other, except of debuggers, most tools should 
care much about the DW_LANG.)

Tobias

PS: Talking about DWARF5, do you know when it will be available as 
public draft? I am especially looking forward to 
http://dwarfstd.org/ShowIssue.php?issue=121221.1 (Allow DW_AT_type with 
DW_TAG_string_type), which would be a low-hanging fruit in terms of 
implementation. Contrary to the array additions of 130313.5.

> As it will take some time for consumers to catch up, I'm enabling that
> only if -gdwarf-5 is used for now.
>
> 2015-01-27  Jakub Jelinek  <jakub@redhat.com>
>
> 	* dwarf2.h (enum dwarf_source_language): Add DW_LANG_Fortran03
> 	and DW_LANG_Fortran08.
> 	* dwarf2out.c (is_fortran): Also return true for DW_LANG_Fortran03
> 	or DW_LANG_Fortran08.
> 	(lower_bound_default): Return 1 for DW_LANG_Fortran03 or
> 	DW_LANG_Fortran08.
> 	(gen_compile_unit_die): Handle "GNU Fortran2003" and
> 	"GNU Fortran2008" language strings.
> 	* dbxout.c (get_lang_number): Use lang_GNU_Fortran.
> 	* langhooks.h (lang_GNU_Fortran): New prototype.
> 	* langhooks.c (lang_GNU_Fortran): New function.
> fortran/
> 	* options.c: Include langhooks.h.
> 	(gfc_post_options): Change lang_hooks.name based on
> 	selected -std= mode.