class Crystal::LLVMId
inherits Reference
¶
This class assigns a pair of IDs {min, max} to every type in the program.
For a regular class or struct (not metaclass), this pair
of ids is such that min is the minimum ID of its subtypes,
and max is 1 + the maximum ID of its subtypes. In this way
we can quickly know if a type implements another type: its ID
must be between {min, max} of such type.
For example, ids could be assigned like this:
- Foo: {1, 8}
- Bar: {1, 2}
- Baz: {1, 1}
- Qux: {3, 3}
- Gen(T): {5, 7}
- Gen(Int32): {4, 4}
- Gen2(T): {5, 6}
- Gen2(Char): {5, 5}
Note that generic instances and generic subtypes are considered as subtypes of a generic type.
For metaclasses IDs are assigned sequentially as they are needed, because dispatch on metaclasses is less often.