llvm dev - Jul 2006 - [LLVMdev] static compilation with the LLVM C frontend

Hello all,

I'm wondering if static compilation using llvm-gcc, i.e. including the 
library code (for example prinft) in the LLVM bytecode, is possible?

I've tried adding the -static option to the llvm-gcc4 compiler, but that 
doesn't seem to change much (I got the same instruction count either 
with or without the option).
Compiling and interpreting a small test program (hello world + a small 
loop), resulted in 240 dynamic instructions on bytecode level. This was 
obtained using lli -stats -force-interpreter on Mac OSX.

When I compile the same program on the Alpha architecture (using gcc 
2.95, but that doesn't matter for these purposes), and count the amount 
of dynamic instructions (using instrumentation with ATOM), I get:
dynamic: 389
static: 4250

Apparently including the library functions (i.e. printf) in the code 
itself, matters a lot. I only used 2 printf calls in my test program. 
The test program is available on 
http://www.elis.ugent.be/~kehoste/hello_with_loop.c,
for anyone who would like to try.

I hope this is possible using LLVM, because otherwise it would mean LLVM 
is not really usefull for me. Any solutions, even compiling glibc 
myself, are an option.

greetings,

Kenneth

-- 
Statistics are like a bikini. What they reveal is suggestive, but what 
they conceal is vital (Aaron Levenstein)

Kenneth Hoste
ELIS - Ghent University
kenneth.hoste at elis.ugent.be
http://www.elis.ugent.be/~kehoste

On Fri, 2006-07-14 at 15:15 +0200, Kenneth Hoste wrote:
> Hello all,
> 
> I'm wondering if static compilation using llvm-gcc, i.e. including the 
> library code (for example prinft) in the LLVM bytecode, is possible?
Static won't help you any.  Unless the library is in bytecode form and
you are linking it in that form before analsis/instrumentation, it will
not be counted.
> I hope this is possible using LLVM, because otherwise it would mean LLVM 
> is not really usefull for me. Any solutions, even compiling glibc 
> myself, are an option.
You need to compile glibc or at least as much of it as you care about
and link it in as bytecode to your application.

Andrew