[LLVMdev] ExecutionEngine always comes back NULL

Kaylor, Andrew andrew.kaylor at intel.com
Wed Jan 9 09:47:11 PST 2013

I agree that it is quite horrible.  I've been bitten by the same problem you had and was equally mystified.  I'm not entirely sure why it was done that way.  It's been like that for as long as I've been working with LLVM.  I'd guess that it had something to do with being able to build and link without the JIT enabled.  I know there's a specific LLVM coding standard against this sort of construct.  We just haven't gotten around to cleaning this up yet.


-----Original Message-----
From: Rick Mann [mailto:rmann at latencyzero.com] 
Sent: Tuesday, January 08, 2013 8:13 PM
To: Kaylor, Andrew
Cc: llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] ExecutionEngine always comes back NULL

On Jan 8, 2013, at 13:55 , "Kaylor, Andrew" <andrew.kaylor at intel.com> wrote:

> You need to include 'llvm/ExecutionEngine/JIT.h' (or 'llvm/ExecutionEngine/JIT.h' if you want that engine) from your main file.  Including that file forces the JIT static constructor to be linked into your executable.  Without it, the JIT static constructor gets optimized out and you get the result you're seeing.

Wow, how obscure! Thank you; I never would've figured that out.

Why is it done that way? That seems...quite horrible, actually. Why not just instantiate the JIT on demand as part of instantiating the Engine?

Thanks again. It works now. Thank you. Thank you.


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