[LLVMdev] GCC3.5 tree-ssa

[Chris Lattner]

On Wed, 24 Dec 2003, yue wrote:

> we work on distribute software development, most programs are wroten in
> java.
> but the running speed of that is slowly,  it requires thread library to
> support, you know.

I'm not sure exactly what you mean here.  LLVM does not currently have a
Java front-end, though there is one in development.  Thread support should
not be a problem, you can make pthreads calls just like you can with any
other compiler.

I'm probably missing your point, can you restate it?

-Chris

> >On Wed, 24 Dec 2003, yue wrote:
> >
> >
> >
> >>why doesn't llvm transfer bytecode to RTL form? I mean the
> >>cross-platform compile in GCC. Could LLVM do that?
> >>
> >>
> >
> >Sure, it would be a realtively straight-forward (but large and hard to get
> >right, if you're not a GCC expert), project to build an LLVM front-end for
> >GCC.  This would allow you to effectively use LLVM as a mid-level
> >representation for GCC, and would allow you to use all of the GCC
> >back-ends with LLVM.
> >
> >However, note that LLVM already does have a C backend, which allows you to
> >interface the LLVM optimizer to GCC or any other platform compiler.  This
> >effectively gives you most of the advantages of a real "RTL backend", with
> >the added advantage that we support the Intel, Sun, SGI, etc compilers as
> >well (at least in theory, we have only tried compiling the CBE output with
> >the GCC and Intel compilers).  Also "C" is a very stable interface
> >language, where the RTL interfaces and APIs are constantly changing.  The
> >one advantage an RTL backend would have over the C backend is speed of
> >compilation.
> >
> >
> >
> >>maybe tree-ssa also create the representation with a testual format if
> >>needed. is it very difficalt? I want to know.
> >>
> >>
> >
> >There are _very strong_ political reasons that will prevent this from
> >happening any time in the near future.  I suggest that you ask on the GCC
> >list if you want more details.  All tree-ssa supports are some debugging
> >dumps, which do not contain all of the information needed for compilation.
> >
> >
> >
> >>BWT: if we port pthread library to llvm, what do we consider at first?
> >>
> >>
> >
> >I'm not sure exactly what you mean.  If it's written in C, you should be
> >able to just compile it with LLVM as you would any other program or
> >library.  Have you run into a problem or bug?
> >
> >-Chris
> >
> >
> >
> >
> >>Chris Lattner wrote:
> >>
> >>
> >>
> >>>On Wed, 24 Dec 2003, yue wrote:
> >>>
> >>>
> >>>
> >>>
> >>>>what difference is between gcc3.5 tree-ssa and llvm?
> >>>>
> >>>>
> >>>>
> >>>>
> >>>They are completely different projects.  The short version is that LLVM is
> >>>more mature and stable than tree-ssa is, LLVM supports interprocedural and
> >>>runtime optimization, and LLVM has a well defined intermediate
> >>>representation with a textual format.  On the other hand tree-ssa may be a
> >>>part of GCC 3.5 someday once it has stabilized and enough bugs have been
> >>>fixed.  Oh, LLVM is written in C++ and tree-ssa is written in C.
> >>>
> >>>If there is something more specific you want to know, please ask.  It's
> >>>very much the difference between apples and oranges.
> >>>
> >>>-Chris
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >
> >-Chris
> >
> >
> >
>
>

-Chris

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