This commit introduces the `irdl.attributes` operation, which allows defining named attributes for the parent operation. Each attribute is defined with a name and a type constraint.
Example usage:
```
irdl.dialect @example {
irdl.operation @attr_op {
%0 = irdl.any
%1 = irdl.is i64
irdl.attributes {
"attr1" = %0,
"attr2" = %1
}
}
}
```
In this example the operation will expect an arbitrary attribute "attr1"
and an attribute "attr2" with value `i64`.
Reviewed By: math-fehr, Mogball
Differential Revision: https://reviews.llvm.org/D152618
f1a0402983