[LLVMdev] Newbie: Target Lowering info.

[Evan Cheng]

On Nov 24, 2007, at 7:28 PM, Sanjiv Gupta wrote:

> Could anybody guide me what information do I need to know about my
> target in order to provide the target lowering info to the llvm DAG
> generator? We do not have any fixed registers for argument passing.
> Everything including the formal and actual arguments will take part in
> a global interprocedural regalloc.

You don't have to formally specify calling convention. For example,  
ARM backend does not have a ARMCallingConv.td file, all the argument  
passing info are implicitly defined in the lowering code.

To start, you should specify legal register files, legal operations,  
etc. See XXXISelLowering.cpp for examples.

Evan

>
>
> Any pointers to learn about this will be a great help.
> Sanjiv
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