llvm dev - Jan 2013 - [LLVMdev] Help! Linking to external functions.

Hi. I've had moderate success so far with LLVM. I've got an OS X app in
Xcode that is able to parse my DSL, generate code into an LLVM Module, and pass
it to an ExecutionEngine to execute.

But now I'm stuck.

That code needs to reference an external function I define in my app. If I
define that function in the same source file as the file that invokes the
ExecutionEngine, everything is fine. But if I define that function in a separate
file, it does not work correctly (LLVM says "LLVM ERROR: Program used
external function 'foo' which could not be resolved!").

I've verified that the function is in fact linked in, by calling it once
from the same code that invokes the ExecutionEngine. This works. But for some
reason, LLVM can't see it. It is 'extern "C"'.

What am I missing? Thanks!

-- 
Rick

Solved my own problem.

I had declared my function inside an 'extern "C"' block like
this:

#ifndef __cplusplus
extern "C" {
#endif

Notice my error? Should be "#ifdef", not "@ifndef".

Durrrr…

-- 
Rick

On Jan 15, 2013, at 18:09 , Rick Mann <rmann at latencyzero.com> wrote:
> Hi. I've had moderate success so far with LLVM. I've got an OS X
app in Xcode that is able to parse my DSL, generate code into an LLVM Module,
and pass it to an ExecutionEngine to execute.
> 
> But now I'm stuck.
> 
> That code needs to reference an external function I define in my app. If I
define that function in the same source file as the file that invokes the
ExecutionEngine, everything is fine. But if I define that function in a separate
file, it does not work correctly (LLVM says "LLVM ERROR: Program used
external function 'foo' which could not be resolved!").
> 
> I've verified that the function is in fact linked in, by calling it
once from the same code that invokes the ExecutionEngine. This works. But for
some reason, LLVM can't see it. It is 'extern "C"'.
> 
> What am I missing? Thanks!
> 
> -- 
> Rick
> 
> 
> 
> 
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