Fields
param: Index,
Populated if there is exactly 1 parameter. Otherwise there are 0 parameters.
align_expr: Index,
Populated if align(A) is present.
addrspace_expr: Index,
Populated if addrspace(A) is present.
section_expr: Index,
Populated if linksection(A) is present.
callconv_expr: Index,
Populated if callconv(A) is present.