[LLVMdev] Adding register allocator to LLVM

Jim Laskey jlaskey at apple.com
Thu Aug 3 04:38:26 CDT 2006

Welcome to the world of pluggable machine passes.  This work was done  
to lighten the load of some llvm tools, ie., only link in the  
register allocators and instruction schedulers that are actually  
needed in a particular circumstance.  I guess I will have to write  
this up, but generally it works like this.

In your register allocator .cpp file add the following include;

   #include ""llvm/CodeGen/RegAllocRegistry.h""

In your register allocator .cpp file define a create function in the  

   FunctionPass *createMyRegisterAllocator() {
     return new MyRegisterAllocator();

and the "installing" static constructor declaration, in the form;

   static RegisterRegAlloc myRegAlloc("myregalloc",
     "  my register allocator help string",

To force the load/linking of your register allocator into the llc/lli  
tools, add your create function's global declaration to "Passes.h"  
and add a "pseudo" call line to "llvm/Codegen/ 
LinkAllCodegenComponents.h" .

And that should do it.


-- Jim

On Aug 3, 2006, at 6:00 AM, Anton Vayvod wrote:

> Hi!
> I'm developing a register allocator and need it to be available as  
> an option for llc tool. I used to edit /lib/CodeGen/Passes.cpp for  
> this aim but after yesterday's update these options are defined  
> somewhere else and I can't find the place.
> Thanks for your help.
> Tony.
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

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