llvm dev - Apr 2013 - [LLVMdev] Does DragonEgg support parameters like -fno-builtin in clang?

Hi,

I have been using clang for quite a while, and I can use `clang
-fno-builtin hello.c` to prevent the generation of llvm built-in functions,
such as llvm.memset. Recently, I switched to gcc with DragonEgg, since the
program to be built is originally designed to be compiled with gcc. I
searched on the web, but did not find any information about how to set
DragonEgg parameters. Could anyone please give me some help? Thanks in
advance!

-- 
Jeff Jia
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On Tue, Apr 09, 2013 at 04:39:14PM -0700, Jeff Jia
wrote:
> Hi,
> 
> I have been using clang for quite a while, and I can use `clang
-fno-builtin
> hello.c` to prevent the generation of llvm built-in functions, such as
> llvm.memset. Recently, I switched to gcc with DragonEgg, since the program
to
> be built is originally designed to be compiled with gcc. I searched on the
web,
> but did not find any information about how to set DragonEgg parameters.
Could
> anyone please give me some help? Thanks in advance!
  Dragonegg is a GCC plugin, I think you can just pass "-fno-builtin"
[1] to gcc. Doesn't it work?

[1]
http://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Option-Summary.html#Option-Summary

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj

Hi Jeff,
> I have been using clang for quite a while, and I can use `clang
-fno-builtin
> hello.c` to prevent the generation of llvm built-in functions, such as
> llvm.memset. Recently, I switched to gcc with DragonEgg, since the program
to be
> built is originally designed to be compiled with gcc. I searched on the
web, but
> did not find any information about how to set DragonEgg parameters. Could
anyone
> please give me some help? Thanks in advance!
dragonegg just uses the same parameters as gcc.  However -fno-builtin has no
effect (this is a bug) because it is surprisingly tricky to get the appropriate
information from inside gcc.  To be more precise: it's not too hard to set
up
something that works OK for C, but then it works poorly for Fortran and Ada.  I
didn't yet come up with a scheme that works well for all languages.

Ciao, Duncan.

Hi chenwj,

Thanks! I have tried it, but the generated byte code still uses
`llvm.memset`. I guess the flag `-fno-builtin` is not used by DragonEgg, or
I missed some other
configuration parameters.


On Tue, Apr 9, 2013 at 7:45 PM, 陳韋任 (Wei-Ren Chen) <chenwj at
iis.sinica.edu.tw
> wrote:
> On Tue, Apr 09, 2013 at 04:39:14PM -0700, Jeff Jia wrote:
> > Hi,
> >
> > I have been using clang for quite a while, and I can use `clang
> -fno-builtin
> > hello.c` to prevent the generation of llvm built-in functions, such as
> > llvm.memset. Recently, I switched to gcc with DragonEgg, since the
> program to
> > be built is originally designed to be compiled with gcc. I searched on
> the web,
> > but did not find any information about how to set DragonEgg
parameters.
> Could
> > anyone please give me some help? Thanks in advance!
>
>   Dragonegg is a GCC plugin, I think you can just pass
"-fno-builtin"
> [1] to gcc. Doesn't it work?
>
> [1]
>
>
http://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Option-Summary.html#Option-Summary
>
> Regards,
> chenwj
>
> --
> Wei-Ren Chen (陳韋任)
> Computer Systems Lab, Institute of Information Science,
> Academia Sinica, Taiwan (R.O.C.)
> Tel:886-2-2788-3799 #1667
> Homepage: http://people.cs.nctu.edu.tw/~chenwj
>


-- 
Jeff Jia
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