This patch adds three functions to the C API:
- mlirAttributeIsALocation: returns true if the attribute is a LocationAttr,
false otherwise.
- mlirLocationGetAttribute: returns the underlying LocationAttr of a Location.
- mlirLocationFromAttribute: gets a Location from a LocationAttr.
Reviewed By: mikeurbach, Mogball
Differential Revision: https://reviews.llvm.org/D142182
7bfdac0e6d