- Move the type parameter from `encode` and `decode` methods to
the trait.
- Remove `UseSpecialized(En|De)codable` traits.
- Remove blanket impls for references.
- Add `RefDecodable` trait to allow deserializing to arena-allocated
references safely.
- Remove ability to (de)serialize HIR.
- Create proc-macros `(Ty)?(En|De)codable` to help implement these new
traits.
Instead of collecting all potential inputs to some metadata entry and
hashing those, we directly hash the values we are storing in metadata.
This is more accurate and doesn't suffer from quadratic blow-up when
many entries have the same dependencies.
This massively speeds up serialization. It also
seems to produce deterministic metadata hashes
(before I was seeing inconsistent results).
Fixes#35232.
This commit reorganizes how the persist code treats hashing. The idea is
that each crate saves a file containing hashes representing the metadata
for each item X. When we see a read from `MetaData(X)`, we can load this
hash up (if we don't find a file for that crate, we just use the SVH for
the entire crate).
To compute the hash for `MetaData(Y)`, where Y is some local item, we
examine all the predecessors of the `MetaData(Y)` node and hash their
hashes together.
Matthew Jasper
Mazdak Farrokhzad
Mark Rousskov
Michael Woerister
Santiago Pastorino
Michael Woerister
Niko Matsakis
Nicholas Nethercote
Seo Sanghyeon
Oliver Schneider