190075Sobrien@c Copyright (C) 2002 Free Software Foundation, Inc.
290075Sobrien@c This is part of the GCC manual.
390075Sobrien@c For copying conditions, see the file gcc.texi.
490075Sobrien
590075Sobrien@node Languages
690075Sobrien@chapter Language Front Ends in GCC
790075Sobrien
890075SobrienThe interface to front ends for languages in GCC, and in particular
990075Sobrienthe @code{tree} structure (@pxref{Trees}), was initially designed for
1090075SobrienC, and many aspects of it are still somewhat biased towards C and
1190075SobrienC-like languages.  It is, however, reasonably well suited to other
1290075Sobrienprocedural languages, and front ends for many such languages have been
1390075Sobrienwritten for GCC@.
1490075Sobrien
1590075SobrienWriting a compiler as a front end for GCC, rather than compiling
1690075Sobriendirectly to assembler or generating C code which is then compiled by
1790075SobrienGCC, has several advantages:
1890075Sobrien
1990075Sobrien@itemize @bullet
2090075Sobrien@item GCC front ends benefit from the support for many different
2190075Sobrientarget machines already present in GCC@.
2290075Sobrien@item GCC front ends benefit from all the optimizations in GCC@.  Some
2390075Sobrienof these, such as alias analysis, may work better when GCC is
2490075Sobriencompiling directly from source code then when it is compiling from
2590075Sobriengenerated C code.
2690075Sobrien@item Better debugging information is generated when compiling
2790075Sobriendirectly from source code than when going via intermediate generated C
2890075Sobriencode.
2990075Sobrien@end itemize
3090075Sobrien
3190075SobrienBecause of the advantages of writing a compiler as a GCC front end,
3290075SobrienGCC front ends have also been created for languages very different
3390075Sobrienfrom those for which GCC was designed, such as the declarative
3490075Sobrienlogic/functional language Mercury.  For these reasons, it may also be
3590075Sobrienuseful to implement compilers created for specialized purposes (for
3690075Sobrienexample, as part of a research project) as GCC front ends.
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