llvm dev - Jul 2012 - [LLVMdev] Preventing pure function declarations from being removed

Hi all,

is there any way to mark a non-referenced function declaration as
"used"
in any way (by using the C++ code generator) so that it will be ignored by  
the stripDeadPrototypes and globalDCE pass (and any other pass that  
possibly might remove seemingly unused functions)?

Basically, my modules have a set of function declarations (without an  
actual body, just a global mapping on the C++ side) that shall not be  
removed during code optimization, because I need to find them again after  
optimization.


Greetings

Marcus

Hi Marcus,
> is there any way to mark a non-referenced function declaration as
"used"
> in any way (by using the C++ code generator) so that it will be ignored by
> the stripDeadPrototypes and globalDCE pass (and any other pass that
> possibly might remove seemingly unused functions)?
try adding it to the llvm.used array.  To see what that is, I suggest you
compile some C code in which you have marked some function with attribute
"used", and observe the use that clang makes of this array.

Ciao, Duncan.