@c Copyright (C) 2002-2018 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.

@node Languages
@chapter Language Front Ends in GCC

The interface to front ends for languages in GCC, and in particular
the @code{tree} structure (@pxref{GENERIC}), was initially designed for
C, and many aspects of it are still somewhat biased towards C and
C-like languages.  It is, however, reasonably well suited to other
procedural languages, and front ends for many such languages have been
written for GCC@.

Writing a compiler as a front end for GCC, rather than compiling
directly to assembler or generating C code which is then compiled by
GCC, has several advantages:

@itemize @bullet
@item GCC front ends benefit from the support for many different
target machines already present in GCC@.
@item GCC front ends benefit from all the optimizations in GCC@.  Some
of these, such as alias analysis, may work better when GCC is
compiling directly from source code then when it is compiling from
generated C code.
@item Better debugging information is generated when compiling
directly from source code than when going via intermediate generated C
code.
@end itemize

Because of the advantages of writing a compiler as a GCC front end,
GCC front ends have also been created for languages very different
from those for which GCC was designed, such as the declarative
logic/functional language Mercury.  For these reasons, it may also be
useful to implement compilers created for specialized purposes (for
example, as part of a research project) as GCC front ends.