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| <a name="Language-Front-Ends-in-GCC"></a> |
| <h2 class="chapter">5 Language Front Ends in GCC</h2> |
| |
| <p>The interface to front ends for languages in GCC, and in particular |
| the <code>tree</code> structure (see <a href="GENERIC.html#GENERIC">GENERIC</a>), 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. |
| </p> |
| <p>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: |
| </p> |
| <ul> |
| <li> GCC front ends benefit from the support for many different |
| target machines already present in GCC. |
| </li><li> 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. |
| </li><li> Better debugging information is generated when compiling |
| directly from source code than when going via intermediate generated C |
| code. |
| </li></ul> |
| |
| <p>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. |
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