Adds the ability to create external passes using the C-API. This allows passes
to be written in C or languages that use the C-bindings.
Differential Revision: https://reviews.llvm.org/D121866
Symbol tables are a largely useful top-level IR construct, for example, they
make it easy to access functions in a module by name instead of traversing the
list of module's operations to find the corresponding function.
Depends On D112886
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D112821
Numerous MLIR functions return instances of `StringRef` to refer to a
non-owning fragment of a string (usually owned by the context). This is a
relatively simple class that is defined in LLVM. Provide a simple wrapper in
the MLIR C API that contains the pointer and length of the string fragment and
use it for Standard attribute functions that return StringRef instead of the
previous, callback-based mechanism.
Reviewed By: stellaraccident
Differential Revision: https://reviews.llvm.org/D87677
