[LLVMdev] [proposal] Extensible IR metadata
dag at cray.com
Fri Sep 11 17:54:31 PDT 2009
On Friday 11 September 2009 19:22, Chris Lattner wrote:
> > - I don't like the separation between "built-in" metadata and
> > "extended"
> > metadata. Why not make all metadata use the RegisterMDKind
> > interface and
> > just have the LLVM libraries do it automatically for the "built-in"
> > stuff?
> > Having a separate namespace of enums is going to get confusing.
> > Practically
> > every day I curse the fact that "int" is different than "MyInt" in C
> > ++. :-/
> "builtin" metadata would also be registered, the only magic would be
> that the encoding would be smaller in the IR.
Except the API is different. Built-in types use a well-known enum
value not available to extended metadata. I have no problem with a
smaller IR encoding. It's the programming interface I'm concerned
about. I'd rather it be the same for everything.
> I don't expect metadata to be commonly stripped. This could be just
> as bad a perf problem for other things like TBAA or high level type
> information for a dynamic language. I think it is important that the
> IR is possible to reason about even in uncommon cases though.
Sure. Just something we need to be aware of.
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