[LLVMdev] TableGen Enhancement Feasibility

[someguy]

Can you give an example of where you would use such a feature?
It seems entirely too abstract (at least to me) at the moment.

On Tue, Apr 7, 2009 at 1:11 AM, David Greene <dag at cray.com> wrote:

> I've got another idea for a tblgen extension but I don't have a good feel
> for
> how feasible it is.  Hopefully someone can provide guidance.
>
> What I want to do is something like this:
>
> class C1<int A, string B> {
>  int foo = A;
>  string bar = B;
> }
>
> class Bb<int A> : C1<A, "foo">;
> class Cb<int A> : C1<A, "bar">;
>
> class C2<C1 Base, int A> : Base<A>;
>
> def I1 : C2<Bb, 1>;
> def I2 : C2<Cb, 2>;
>
> and this:
>
> class Z<int A> {
>  int moo = A;
> }
>
> class Z1 : Z<1>;
> class Z2 : Z<2>;
>
> multiclass C2<int A, string B, Z ZZ> {
>  def D1 : Bb<A>, ZZ;
>  def D2 : Cb<A>, ZZ;
> }
>
> defm D3 : C2<1, Z1>;
> defm D4 : C2<2, Z2>;
>
> Right now tblgen doesn't understand class name arguments like this as it
> expects to resolve subclasses immediately.  Being able to resolve
> subclasses
> lazily would open up a whole lot of opportunity to reduce redundancy in .td
> files.
>
> My sense is to implement this we'd need something like a ClassInit
> (analogous
> to a VarInit) and a call to resolve references at the right time.  But I
> don't
> know how deeply coded subclasses are in tblgen.  Are things going to break
> spectacularly if subclass information isn't available immediately?
>
> Anyone have a sense of the amount of work to add a feature like this?
>
>                                                 -Dave
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20090407/3b88156f/attachment.html>