[PATCH] D19871: Add an AST matcher for CastExpr kind

[Aaron Ballman via cfe-commits]

aaron.ballman added a comment.

In http://reviews.llvm.org/D19871#420095, @etienneb wrote:

> > I agree that when possible, matchers should be available via the dynamic matchers API. It doesn't seem overly complicated to add this support here. As far as I understand, we just need to register the matcher in lib/ASTMatchers/Dynamic/Registry.cpp and add support for `CastKind` argument type (by adding a corresponding `ArgTypeTraits` instantiation). Etienne, can you try this?
>
>
>
>
> 1. The parameter is passed as a string (which is not the case for the hasCastKind matcher): hasAttr("attr::CUDADevice").


Correct. The dynamic registry has no support for enumerations of values, and so it uses strings instead. I think that's fine here as well.

> 2. There is no easy way to list every cast kind. Which means we need to hardcode them (or iterate over the domain) [both solution sounds terrible to me]. ``` static clang::CastKind getCastKind(llvm::StringRef AttrKind) { return llvm::StringSwitch<clang::CastKind>(AttrKind) .Case("CK_Dependent", CK_Dependent) [...]    <<-- list every cast kind here. .Default(clang::CastKind(-1)); } ```


This is unfortunate, but is likely the way we would move forward.

> So even if the above solution is working, we still need to call it that way (as a string):

>  clang-query> match castExpr(hasCastKind("CK_Dependent"))


Correct, that's expected behavior for clang-query (though I would love if someday we could expose actual enumerations somehow instead of string literals).


http://reviews.llvm.org/D19871