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Flesh out the dragonegg section.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115179 91177308-0d34-0410-b5e6-96231b3b80d8
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Duncan Sands 2010-09-30 17:37:34 +00:00
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docs/ReleaseNotes.html
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@ -240,28 +240,33 @@ Soft float support
<div class="doc_text">
<p>
<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
whatsoever (currently one small patch is needed). This is thanks to the new
<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
which is nothing more than a dynamic library which conforms to the gcc plugin
interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
instead of the gcc optimizers, and the LLVM code generators instead of the gcc
code generators, just like llvm-gcc. To use it, you add
"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
becomes llvm-gcc-4.5!
gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
modifications whatsoever (currently one small patch is needed) thanks to the
new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
generators instead of gcc's, just like with llvm-gcc.
</p>
<p>
DragonEgg is still a work in progress. Currently C works very well, while C++,
Ada and Fortran work fairly well. All other languages either don't work at all,
or only work poorly. For the moment only the x86-32 and x86-64 targets are
supported, and only on linux and darwin (darwin needs an additional gcc patch).
DragonEgg is still a work in progress, but it is able to compile a lot of code,
for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
well, while all other languages either don't work at all or only work poorly.
For the moment only the x86-32 and x86-64 targets are supported, and only on
linux and darwin (darwin may need additional gcc patches).
</p>
<p>
2.8 status here.
The 2.8 release has the following notable changes:
<ul>
<li>The plugin loads faster due to exporting fewer symbols.</li>
<li>Additional vector operations such as addps256 are now supported.</li>
<li>Ada global variables with no initial value are no longer zero initialized,
resulting in better optimization.</li>
<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
optimizers, rather than just a handful.</li>
<li>Fortran programs using common variables now link correctly.</li>
<li>GNU OMP constructs no longer crash the compiler.</li>
</ul>
</p>
</div>