llvm dev - Mar 2007 - [LLVMdev] JIT slow

Hi!

It appeared to me that runFunction in JIT.cpp is slow for repeatedly
executing the same function with nontrivial arguments since the "Stub"
function in JiT.cpp:183 (LLVM 1.9) is compiled again and again.
Is there something I can do to accelerate this?

g

On 2007-03-15, at 11:42, Gonsolo wrote:
> It appeared to me that runFunction in JIT.cpp is slow for  
> repeatedly executing the same function with nontrivial arguments  
> since the "Stub" function in JiT.cpp:183 (LLVM 1.9) is compiled  
> again and again. Is there something I can do to accelerate this?
Hi G,

Have you tried using this method instead?

   /// getPointerToFunctionOrStub - If the specified function has been
   /// code-gen'd, return a pointer to the function.  If not, compile  
it, or use
   /// a stub to implement lazy compilation if available.
   ///
   virtual void *getPointerToFunctionOrStub(Function *F);

If you can use it, this eliminates out the overhead in question,  
reducing it to an indirect function call.

— G

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