[LLVMdev] Compiling whole programs to bitcode

[Charles Davis]

On 6/3/11 10:12 PM, Russell Wallace wrote:
> With Clang, it's reasonably straightforward to compile a C/C++ file to bitcode.
> 
> Is there a way to compile a program together with all the standard
> library functions it uses, to that format? That is, suppose you have
> hello.c that calls printf, how would you go about generating the
> bitcode representation of both the main function from hello.c, and
> printf itself (plus whatever other standard library functions printf
> calls)?
> 
> Or put another way, given that one answer to the above question would
> be 'download the source of GNU libc, manually run Clang to compile the
> whole lot to bitcode, then manually extract the bitcode versions of
> the functions you are interested in,'  is there a more automated way
> to do it (in the sense that a linker provides a more automated way to
> do a similar job of building an executable)?
You can link your bitcode together with glibc's bitcode by using the
llvm-link utility. Then you can run DCE over the bitcode with "opt -dce"
and cull all the functions you don't need.

But why are you trying to do this at all?

Chip