[LLVMdev] Analysis Pass

John Criswell criswell at cs.uiuc.edu
Mon Jun 8 07:34:05 PDT 2009

Rotem Varon wrote:
> Hi,
> I am trying to set a prerequisite pass.
> void PassName::getAnalysisUsage(AnalysisUsage &AU) const
>     {
>         AU.setPreservesAll();
>         AU.addRequired<LiveVariables>();
>     }
> But when i am running the pass with the opt i get this error:
> undefined symbol: _ZN4llvm13LiveVariables2IDE
I'm not sure if this has already been answered, so I'll answer it.

The reason why you're getting this error is because the code containing
the LiveVariables pass is not compiled into the opt program and it is
not loaded into the opt program via the -load option.  The reason for
that, I suspect, is that LiveVariables, I believe, is a pass that is
used for code generation (i.e., it is not a pure LLVM IR
transformation), so it is not included in opt.

-- John T.

> If you need more information ...
> Thank you.

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