[LLVMdev] Preferring to use GCC instead of LLVM

[Bill Wendling]

On May 10, 2008, at 3:06 AM, kr512 wrote:

>
> Oh another thing, consider this question that some people
> will be asking:  Why not use GCC to do what LLVM does, and
> skip the hassle of using LLVM entirely?
>
> ESPECIALLY considering that LLVM cannot be used without GCC.
> Even if you are using LLVM as a back-end only, for compiling
> LLVM bytecode only, GCC is still required to convert the
> "llc" output assembly .S file into a ready-to-execute native
> machine code .EXE or .DLL file.
>
I don't know about your computer, by mine comes with an assembler. GCC  
invokes this assembler, and I can invoke it from the command line just  
fine.

> Thus if LLVM is an incomplete back-end replacement for GCC,
> why not just use the normal version of GCC?
>
> I do understand the LLVM project and I think it is great and
> very worthwhile,

This I agree with.

-bw

> but while LLVM cannot be used as a complete
> back-end by itself, then GCC is a more attractive solution
> for our project.
>
> See, in our project, we have a front-end compiler.  For
> input to the back-end, we can generate LLVM bytecode, or we
> can generate C source code, and then we need it converted to
> a native machine code .EXE or DLL ready to load and run.  So
> you see, either GCC or LLVM can be used as our back-end.
>
> Now what advantage does LLVM have that will entice us to
> pick LLVM over GCC?   LLVM is smaller?  Not really, because
> LLVM still requires the use of GCC for the .S file, as I
> said above.
>
> LLVM would be a considerably more attractive solution than
> GCC *if* the following were true:
> (a) LLVM could be used as a back-end without use of GCC.
> Meaning LLVM by itself can generate a ready-to-execute .EXE
> or .DLL file.
> (b) LLVM was provided as a precompiled DLL, not only as
> command-line tools.
>
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