1*ec02198aSmrg@c Copyright (C) 2002-2020 Free Software Foundation, Inc. 210d565efSmrg@c This is part of the GCC manual. 310d565efSmrg@c For copying conditions, see the file gcc.texi. 410d565efSmrg 510d565efSmrg@node Languages 610d565efSmrg@chapter Language Front Ends in GCC 710d565efSmrg 810d565efSmrgThe interface to front ends for languages in GCC, and in particular 910d565efSmrgthe @code{tree} structure (@pxref{GENERIC}), was initially designed for 1010d565efSmrgC, and many aspects of it are still somewhat biased towards C and 1110d565efSmrgC-like languages. It is, however, reasonably well suited to other 1210d565efSmrgprocedural languages, and front ends for many such languages have been 1310d565efSmrgwritten for GCC@. 1410d565efSmrg 1510d565efSmrgWriting a compiler as a front end for GCC, rather than compiling 1610d565efSmrgdirectly to assembler or generating C code which is then compiled by 1710d565efSmrgGCC, has several advantages: 1810d565efSmrg 1910d565efSmrg@itemize @bullet 2010d565efSmrg@item GCC front ends benefit from the support for many different 2110d565efSmrgtarget machines already present in GCC@. 2210d565efSmrg@item GCC front ends benefit from all the optimizations in GCC@. Some 2310d565efSmrgof these, such as alias analysis, may work better when GCC is 2410d565efSmrgcompiling directly from source code then when it is compiling from 2510d565efSmrggenerated C code. 2610d565efSmrg@item Better debugging information is generated when compiling 2710d565efSmrgdirectly from source code than when going via intermediate generated C 2810d565efSmrgcode. 2910d565efSmrg@end itemize 3010d565efSmrg 3110d565efSmrgBecause of the advantages of writing a compiler as a GCC front end, 3210d565efSmrgGCC front ends have also been created for languages very different 3310d565efSmrgfrom those for which GCC was designed, such as the declarative 3410d565efSmrglogic/functional language Mercury. For these reasons, it may also be 3510d565efSmrguseful to implement compilers created for specialized purposes (for 3610d565efSmrgexample, as part of a research project) as GCC front ends. 37