Enum Backend 

pub(crate) enum Backend {
    Ast,
    Vm,
}

Which backend produced a number.

ADR 0019 requires every number this harness reports to say so, because the two are not interchangeable: fuel_spent is defined per backend, and a wall-clock figure that did not name its backend would be a comparison missing half of itself.

Variants

Ast

The tree-walking interpreter, which is the oracle: it runs every construct the language has, straight off the checked program, with no lowering of its own and nothing to refuse.

Vm

The linear-memory backend of ADR 0034, over cove_ir.

The production path. ADR 0034 replaced the executable IR, the lowering, the VM, and — once the replacement had proven itself — an experimental eight-byte-word frame that existed only to make the two backends’ comparison measurable within one build; its completion condition 8 was to delete all of that once this backend took over, which is why vm is the only lowered backend left here.

It has no admission predicate. cove_ir refuses nothing on purpose — a construct it has not been taught is a gap in the lowering rather than a program the backend declines — so a vm row that is missing is a bug, and this harness reports one as a failure.

Implementations

impl Backend

pub(crate) fn kind(self) -> &'static str

The value of the kind field, which keeps the string the interpreter’s rows have always carried so that a reader of the older format finds exactly the rows it was reading and no more.

pub(crate) fn parse(name: &str) -> Option<Backend>

The name --backend accepts for this backend, and the one a row is reported under.

Trait Implementations

impl Clone for Backend

fn clone(&self) -> Backend

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Backend

impl Debug for Backend

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Backend

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Backend

impl PartialEq for Backend

fn eq(&self, other: &Backend) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Backend