@c Copyright (C) 2002 Free Software Foundation, Inc.
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@c Copyright (C) 2002 Free Software Foundation, Inc.
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@c This is part of the GCC manual.
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@c This is part of the GCC manual.
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@c For copying conditions, see the file gcc.texi.
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@c For copying conditions, see the file gcc.texi.
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@node Languages
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@node Languages
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@chapter Language Front Ends in GCC
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@chapter Language Front Ends in GCC
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The interface to front ends for languages in GCC, and in particular
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The interface to front ends for languages in GCC, and in particular
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the @code{tree} structure (@pxref{Trees}), was initially designed for
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the @code{tree} structure (@pxref{Trees}), was initially designed for
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C, and many aspects of it are still somewhat biased towards C and
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C, and many aspects of it are still somewhat biased towards C and
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C-like languages. It is, however, reasonably well suited to other
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C-like languages. It is, however, reasonably well suited to other
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procedural languages, and front ends for many such languages have been
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procedural languages, and front ends for many such languages have been
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written for GCC@.
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written for GCC@.
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Writing a compiler as a front end for GCC, rather than compiling
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Writing a compiler as a front end for GCC, rather than compiling
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directly to assembler or generating C code which is then compiled by
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directly to assembler or generating C code which is then compiled by
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GCC, has several advantages:
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GCC, has several advantages:
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@itemize @bullet
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@itemize @bullet
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@item GCC front ends benefit from the support for many different
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@item GCC front ends benefit from the support for many different
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target machines already present in GCC@.
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target machines already present in GCC@.
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@item GCC front ends benefit from all the optimizations in GCC@. Some
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@item GCC front ends benefit from all the optimizations in GCC@. Some
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of these, such as alias analysis, may work better when GCC is
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of these, such as alias analysis, may work better when GCC is
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compiling directly from source code then when it is compiling from
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compiling directly from source code then when it is compiling from
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generated C code.
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generated C code.
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@item Better debugging information is generated when compiling
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@item Better debugging information is generated when compiling
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directly from source code than when going via intermediate generated C
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directly from source code than when going via intermediate generated C
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code.
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code.
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@end itemize
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@end itemize
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Because of the advantages of writing a compiler as a GCC front end,
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Because of the advantages of writing a compiler as a GCC front end,
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GCC front ends have also been created for languages very different
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GCC front ends have also been created for languages very different
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from those for which GCC was designed, such as the declarative
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from those for which GCC was designed, such as the declarative
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logic/functional language Mercury. For these reasons, it may also be
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logic/functional language Mercury. For these reasons, it may also be
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useful to implement compilers created for specialized purposes (for
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useful to implement compilers created for specialized purposes (for
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example, as part of a research project) as GCC front ends.
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example, as part of a research project) as GCC front ends.
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