clattner at apple.com
Wed Nov 12 15:29:21 PST 2008
On Nov 12, 2008, at 2:59 PM, David Greene wrote:
> Is there some reason that RefineAbstractType doesn't recurse down
> and further resolve abstract types?
Because that would resolve two different types. RefineAbstractType
just refines the one type you request, and further uniques types based
In fact, I strongly suspect that RefineAbstractType doesn't work if
you give it something that isn't Opaque. I'd recommend only using it
on Opaque, not random abstract types.
> In Fortran it is possible to have a routine that takes a function
> pointer to a
> routine with the same signature. This is not possible to express in
> I'm not sure it's possible to express in LLVM either without using
> (opinions welcome).
Sure, LLVM is more general than C. In LLVM, you can have a pointer
that points to itself, for example:
%t = type %t*
which is "\1*" if you like up references.
I'm not sure what a function pointer that takes a pointer to itself
has to do with opaque types, but you'd write it like this:
%t = type void (%t)*
or if you want the function:
%t = type void (%t*)
> Unfortunately, calling FunctionType::refineAbstractType(opaque, void
> doesn't work because RefineAbstractType doesn't recurse down into the
> pointee types.
What types are you starting out with? If you had the equivalent of:
%t1 = type opaque
%t2 = type void(%t1*)
and you refine t1 -> t2, it should work.
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