[patch, fortran] PR18428: use libcpp for preprocessing (review of C/C++ and fortran maintainers needed)

[Tobias Burnus]

* PING*

at least to my knowledge the C/C++ part is still unapproved. 
(François-Xavier approved the Fortran part.) 
http://gcc.gnu.org/ml/gcc-patches/2008-04/msg01753.html

Tobias

Daniel Franke wrote:
> Hi all.
>
> This is to integrate libcpp into gfortran and not to rely on cc1 to do the 
> preprocessing. The change became necessary to simplify the implementation of 
> feature requests and fixing of problems related to preprocessing.
>
> Essentially, this patch does not change anything for the outside world but one 
> detail: to preprocess files it is not necessary to rename x.f90 to x.F90, one 
> now can also invoke:
>
> 	$> gfortran -cpp x.f90
>
> Hence, any workarounds using "-x f95-cpp-input" or resorting to .spec-files is 
> now obsolete.
>
> The C changes may be devided into two parts: firstly, the cleanup of an 
> undocumented option and its handling; secondly, moving some functionality 
> from gcc to libbackend to be reused by the fortran frontend (see also [1]). 
> The latter changes should be reviewed very carefully as I am not very 
> involved in with the build process ...
>
> On the fortran side, the largest part of the changes went into the new files 
> cpp.[ch] - large portions of that code were borrowed from c-ppoutput. Any 
> outside change should be simple and straight forward.
>
> Still to do: general clean- and brushing up, testcases and documentation.
>
> Besides the TODO items, I plan to implement/fix the following PRs next:
>  * PR31588 - Makefile dependencies with -M* options
>  * PR35707 - additional search paths for .mod files
>  * PR35505 - missing path to finclude directory when compiling .F90 files
>
> If the requirement of traditional-cpp can be dropped:
>  * PR28662 - traditional-cpp versus newer macros like #x
>  * PR29671 - preprocessor statements must start in column 1
>
> Thanks to Tom Tromey and all others who helped me to implement this so far!
>
>
> :ADDPATCH gcc/fortan:
>
> gcc:
> 2008-04-23  Daniel Franke  <franke.daniel@gmail.com>
>
> 	PR fortran/18428
> 	* c.opt: Removed undocumented option '-lang-fortran'.
> 	* c-common.h: Removed global variable 'lang_fortran'.
> 	* c-opts.c (c_common_handle_option): Removed code to handle
> 	option '-lang-fortran'.
> 	* c-cppbuiltin.c (c_cpp_builtins): Removed conditional
> 	definition of '__GFORTRAN__'.
> 	(define__GNUC__): Reimplemented to use BASEVER and 
> 	cpp_define_formatted.
> 	(builtin_define_with_value_n): Removed.
> 	* c-incpath.h: Renamed to ...
> 	* incpath.h: ... this.
> 	* c-incpath.c: Renamed to ...
> 	* incpath.c: ... this.
> 	* fix-header.c: Updated includes.
> 	* Makefile.in: Replaced c-incpath.[ch] by incpath.[ch].
> 	(c-cppbuiltin.o): Added dependency on and definition of BASEVER.
> 	(OBJ-archive): Added cppdefault.o, incpath.o and prefix.o.
> 	(PROTO_OBJS): Adjusted dependencies.
> 	(fix-header): Likewise.
>
>
> gcc/cp:
> 2008-04-23  Daniel Franke  <franke.daniel@gmail.com>
>
> 	* Makefile.in: Adjusted dependencies.
>
>
> gcc/fortran:
> 2008-04-23  Daniel Franke  <franke.daniel@gmail.com>
>
> 	PR fortran/18428
> 	* lang.opt (A, C, CC, D, E, H, P, U, cpp, d, fworking-directory,
> 	imultilib, iprefix, iquote, isysroot, isystem, nostdinc, o, undef, v): 
> 	New options.
> 	* options.c (gfc_init_options): Also initialize preprocessor
> 	options.
> 	(gfc_post_options): Also handle post-initialization of preprocessor
> 	options.
> 	(gfc_handle_option): Check if option is a preprocessor option.
> 	If yes, let gfc_cpp_handle_option() handle the option.
> 	* lang-specs.h: Reorganized to handle new options.
> 	* scanner.c (gfc_new_file): Read temporary file instead of 
> 	input source if preprocessing is enabled.
> 	* f95-lang.c (gfc_init): Initialize preprocessor.
> 	(gfc_finish): Clean up preprocessor.
> 	* cpp.c: New.
> 	* cpp.h: New.
> 	* Make-lang.in: Added new objects and dependencies.
>
>
> Bootstrapped and regression tested on i686-pc-linux-gnu.
> Ok for trunk?
>
> Regards
>
> 	Daniel
>
> P.S. To apply the patch, one needs to manually rename c-incpath.[ch], 
> otherwise it won't apply cleanly.
>
> [1] http://gcc.gnu.org/ml/gcc/2008-04/msg00389.html
>