[LLVMdev] Adding intrinsic with variable argument list HOWTO.

[Evan Cheng]

On Aug 3, 2007, at 3:07 AM, Mikael Lepistö wrote:

> Hi, I've been hitting my head to wall two days now. This is  
> practically
> my first contact with InstrInfo.td files. Is there any tutorial how to
> make this kind of stuff? Or should I just keep on studying Sparc and
> other backends?

Unfortunately studying other targets (and trial and error) is the  
best way. This is not well documented.

>
> So I added new intrinsic to llvm/include/llvm/TCEInstrinsics.td:
>
> def int_tce_customop :
>     Intrinsic<[llvm_void_ty, llvm_ptr_ty, llvm_vararg_ty], [],
> "llvm.tce.customop">;
>
> I made opt pass that converts __custom_op() functions to calls to
> llvm.tce.customop calls.
>
> shell> grep llvm.tce.customop hello2.ll
>         tail call void (i8*, ...)* @llvm.tce.customop( i8*  
> getelementptr
> ([7 x i8]* @.str, i32 0, i32 0), i32 %tmp78 )
>         tail call void (i8*, ...)* @llvm.tce.customop( i8*  
> getelementptr
> ([7 x i8]* @.str, i32 0, i32 0), i32 10 )
>         tail call void (i8*, ...)* @llvm.tce.customop( i8*  
> getelementptr
> ([7 x i8]* @.str, i32 0, i32 0), i32 %tmp12 )
> declare void @llvm.tce.customop(i8*, ...)
>
> No I need to add code to llvm/lib/Target/TCE/TCEInstrInfo.td, for
> recognizing that variable argument intrinsic and I have no idea how  
> it's
> done. Right now I'm trying following:
>
> def CustomOpParams : SDTypeProfile<0,2,[]>;
>
> def customop       : SDNode<"ISD::INTRINSIC_VOID", CustomOpParams>;
>
> def : Pat<(customop tglobaladdr:$dst,iPTR:$vararg),
>           (int_tce_customop tglobaladdr:$dst, iAny:$vararg)>;
>
> def : Pat<(call texternalsym:$dst,iAny:$vararg),
>           (int_tce_customop texternalsym:$dst, iAny:$vararg)>;

You want to match an intrinsic pattern to a particular target  
instruction. Try something like

def customop_i8 : I<(outs), (ins r8:$dst, variable_ops), "customop  
$dst",
                                     [(int_tce_customop tglobaladdr: 
$dst)]>;

variable_ops means the instruction has variable number of operands.

You can also use the def : Pat syntax. But you still need the  
instruction definition. Then
def : Pat<(int_tce_customop tglobaladdr:$dst), (customop tglobaladdr: 
$dst)>

Note variable_ops isn't needed on the def : Pat rule, just on the  
instruction.

Hope this helps.

Evan

>
>
> but compilation gives following error:
>
> isVoid:void anonymous.52:       (intrinsic_void:void 197:iPTR,
> (tglobaladdr:iPTR):$dst, isVoid:void)
> /home/elhigu/llvm-install/llvm/Release/bin/tblgen: In anonymous.52:  
> Type
> inference contradiction found in node!
>
> Mikael Lepistö
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