Function get_constraint

cranelift/codegen/meta/src/gen_inst.rs:788–814

Get the value type constraint for an SSA value operand, where `ctrl_typevar` is the controlling type variable. Each operand constraint is represented as a string, one of: - `Concrete(vt)`, where `vt` is a value type name. - `Free(idx)` where `idx` is an index into `type_sets`. - `Same`, `Lane`, `AsTruthy` for controlling typevar-derived constraints.

(
    operand: &'entries Operand,
    ctrl_typevar: Option<&TypeVar>,
    type_sets: &'table mut UniqueTable<'entries, TypeSet>,
)

/// - `Free(idx)` where `idx` is an index into `type_sets`.
/// - `Same`, `Lane`, `AsTruthy` for controlling typevar-derived constraints.
fn get_constraint<'entries, 'table>(
    operand: &'entries Operand,
    ctrl_typevar: Option<&TypeVar>,
    type_sets: &'table mut UniqueTable<'entries, TypeSet>,
) -> String {
    assert!(operand.is_value());
    let type_var = operand.type_var().unwrap();

    if let Some(typ) = type_var.singleton_type() {
        return format!("Concrete({})", typ.rust_name());
    }

    if let Some(free_typevar) = type_var.free_typevar() {
        if ctrl_typevar.is_some() && free_typevar != *ctrl_typevar.unwrap() {
            assert!(type_var.base.is_none());
            return format!("Free({})", type_sets.add(type_var.get_raw_typeset()));
        }
    }

    if let Some(base) = &type_var.base {
        assert!(base.type_var == *ctrl_typevar.unwrap());
        return camel_case(base.derived_func.name());
    }

    assert!(type_var == ctrl_typevar.unwrap());
    "Same".into()
}

fn gen_bitset<'a, T: IntoIterator<Item = &'a u16>>(
    iterable: T,