##### 6.3.8.1 The Front End `language` Directory

A front end `language` directory contains the source files of that front end (but not of any runtime libraries, which should be outside the `gcc` directory). This includes documentation, and possibly some subsidiary programs build alongside the front end. Certain files are special and other parts of the compiler depend on their names:

`config-lang.in`
  This file is required in all language subdirectories. See The Front End `config-lang.in` File, for details of its contents
`Make-lang.in`
  This file is required in all language subdirectories. It contains targets lang`.`hook (where lang is the setting of `language` in `config-lang.in`) for the following values of hook, and any other Makefile rules required to build those targets (which may if necessary use other Makefiles specified in `outputs` in `config-lang.in`, although this is deprecated). It also adds any testsuite targets that can use the standard rule in `gcc/Makefile.in` to the variable `lang_checks`.
  `all.cross`
  `start.encap`
  `rest.encap`
    FIXME: exactly what goes in each of these targets?
  `tags`
    Build an `etags` `TAGS` file in the language subdirectory in the source tree.
  `info`
    Build info documentation for the front end, in the build directory. This target is only called by ‘`make bootstrap`’ if a suitable version of `makeinfo` is available, so does not need to check for this, and should fail if an error occurs.
  `dvi`
    Build DVI documentation for the front end, in the build directory. This should be done using `$(TEXI2DVI)`, with appropriate `-I` arguments pointing to directories of included files.
  `pdf`
    Build PDF documentation for the front end, in the build directory. This should be done using `$(TEXI2PDF)`, with appropriate `-I` arguments pointing to directories of included files.
  `html`
    Build HTML documentation for the front end, in the build directory.
  `man`
    Build generated man pages for the front end from Texinfo manuals (see Man Page Generation), in the build directory. This target is only called if the necessary tools are available, but should ignore errors so as not to stop the build if errors occur; man pages are optional and the tools involved may be installed in a broken way.
  `install-common`
    Install everything that is part of the front end, apart from the compiler executables listed in `compilers` in `config-lang.in`.
  `install-info`
    Install info documentation for the front end, if it is present in the source directory. This target should have dependencies on info files that should be installed.
  `install-man`
    Install man pages for the front end. This target should ignore errors.
  `srcextra`
    Copies its dependencies into the source directory. This generally should be used for generated files such as Bison output files which are not present in CVS, but should be included in any release tarballs. This target will be executed during a bootstrap if ‘`--enable-generated-files-in-srcdir`’ was specified as a `configure` option.
  `srcinfo`
  `srcman`
    Copies its dependencies into the source directory. These targets will be executed during a bootstrap if ‘`--enable-generated-files-in-srcdir`’ was specified as a `configure` option.
  `uninstall`
    Uninstall files installed by installing the compiler. This is currently documented not to be supported, so the hook need not do anything.
  `mostlyclean`
  `clean`
  `distclean`
  `maintainer-clean`
    The language parts of the standard GNU ‘`*clean`’ targets. See Standard Targets for Users, for details of the standard targets. For GCC, `maintainer-clean` should delete all generated files in the source directory that are not checked into CVS, but should not delete anything checked into CVS.
  `stage1`
  `stage2`
  `stage3`
  `stage4`
  `stageprofile`
  `stagefeedback`
    Move to the stage directory files not included in `stagestuff` in `config-lang.in` or otherwise moved by the main `Makefile`.
`lang.opt`
  This file registers the set of switches that the front end accepts on the command line, and their `--help` text. See Options.
`lang-specs.h`
  This file provides entries for `default_compilers` in `gcc.c` which override the default of giving an error that a compiler for that language is not installed.
`language-tree.def`
  This file, which need not exist, defines any language-specific tree codes.