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Auto merge of #95573 - cjgillot:lower-query, r=michaelwoerister

Make lowering a query

Split from https://github.com/rust-lang/rust/pull/88186.

This PR refactors the relationship between lowering and the resolver outputs in order to make lowering itself a query.
In a first part, lowering is changed to avoid modifying resolver outputs, by maintaining its own data structures for creating new `NodeId`s and so.

Then, the `TyCtxt` is modified to allow creating new `LocalDefId`s from inside it. This is done by:
- enclosing `Definitions` in a lock, so as to allow modification;
- creating a query `register_def` whose purpose is to declare a `LocalDefId` to the query system.

See `TyCtxt::create_def` and `TyCtxt::iter_local_def_id` for more detailed explanations of the design.
This commit is contained in:
bors 2022-07-07 18:14:44 +00:00
commit 0f573a0c54
37 changed files with 462 additions and 391 deletions

View file

@ -701,16 +701,20 @@ fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut S
// If we cannot evaluate the constant to a known type, we fall back
// to emitting a stable hash value of the constant. This isn't very pretty
// but we get a deterministic, virtually unique value for the constant.
let hcx = &mut tcx.create_stable_hashing_context();
let mut hasher = StableHasher::new();
let ct = ct.eval(tcx, ty::ParamEnv::reveal_all());
hcx.while_hashing_spans(false, |hcx| ct.to_valtree().hash_stable(hcx, &mut hasher));
//
// Let's only emit 64 bits of the hash value. That should be plenty for
// avoiding collisions and will make the emitted type names shorter.
// Note: Don't use `StableHashResult` impl of `u64` here directly, since that
// would lead to endianness problems.
let hash: u128 = hasher.finish();
let hash_short = (hash.to_le() as u64).to_le();
let hash_short = tcx.with_stable_hashing_context(|mut hcx| {
let mut hasher = StableHasher::new();
let ct = ct.eval(tcx, ty::ParamEnv::reveal_all());
hcx.while_hashing_spans(false, |hcx| {
ct.to_valtree().hash_stable(hcx, &mut hasher)
});
// Note: Don't use `StableHashResult` impl of `u64` here directly, since that
// would lead to endianness problems.
let hash: u128 = hasher.finish();
(hash.to_le() as u64).to_le()
});
if cpp_like_debuginfo(tcx) {
write!(output, "CONST${:x}", hash_short)