Hi,

I'm trying to understand a few implementation details of gcc for implementing a 
new warning.  For that, I first read the GCC manual [1].

[1]: <https://gcc.gnu.org/onlinedocs/gcc-12.2.0/gcc.pdf>

However, that manual has nothing about internals, such as 'LangEnabledBy()'.
Then I checked what's in the root of the repo to see what I can read:

     $ ls
     ABOUT-NLS           config-ml.in  libcody          libvtv
     COPYING             config.guess  libcpp           ltgcc.m4
     COPYING.LIB         config.rpath  libdecnumber     ltmain.sh
     COPYING.RUNTIME     config.sub    libffi           lto-plugin
     COPYING3            configure     libgcc           ltoptions.m4
     COPYING3.LIB        configure.ac  libgfortran      ltsugar.m4
     ChangeLog           contrib       libgo            ltversion.m4
     ChangeLog.jit       depcomp       libgomp          lt~obsolete.m4
     ChangeLog.tree-ssa  fixincludes   libiberty        maintainer-scripts
     INSTALL             gcc           libitm           missing
     MAINTAINERS         gnattools     libobjc          mkdep
     Makefile.def        gotools       liboffloadmic    mkinstalldirs
     Makefile.in         include       libphobos        move-if-change
     Makefile.tpl        install-sh    libquadmath      multilib.am
     README              intl          libsanitizer     symlink-tree
     ar-lib              libada        libssp           test-driver
     c++tools            libatomic     libstdc++-v3     ylwrap
     compile             libbacktrace  libtool-ldflags  zlib
     config              libcc1        libtool.m4

The only interesting file seems to be the README.  Let's see what it says:

> The directory INSTALL contains copies of the installation information
> as HTML and plain text.  The source of this information is
> gcc/doc/install.texi.  The installation information includes details
> of what is included in the GCC sources and what files GCC installs.
> 
> See the file gcc/doc/gcc.texi (together with other files that it
> includes) for usage and porting information.  An online readable
> version of the manual is in the files gcc/doc/gcc.info*.

Okay, let's see the online readable version of the manual:

     $ ls gcc/doc/gcc.info*
     ls: cannot access 'gcc/doc/gcc.info*': No such file or directory

No files with that glob(7).  BTW, it might be interesting to provide that manual 
in a package, so that I could install it as something like:

     apt-get install gcc-doc-internal

Cheers,

Alex

-- 
<http://www.alejandro-colomar.es/>