bjoernager/rust
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Simplify metadata decoding.

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This commit is contained in:
Camille GILLOT 2021-06-27 10:03:10 +02:00
parent 47ea2ae933
commit c2d43e1329
2 changed files with 12 additions and 44 deletions
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38
compiler/rustc_span/src/hygiene.rs
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@ -1136,14 +1136,12 @@ pub fn decode_expn_id_incrcomp<D: Decoder>(
Ok(expn_id)
}
pub fn decode_expn_id<'a, D: Decoder>(
pub fn decode_expn_id<D: Decoder>(
d: &mut D,
get_context: impl FnOnce(CrateNum) -> &'a HygieneDecodeContext,
decode_data: impl FnOnce(&mut D, u32) -> Result<(ExpnData, ExpnHash), D::Error>,
decode_data: impl FnOnce(CrateNum, u32) -> (ExpnData, ExpnHash),
) -> Result<ExpnId, D::Error> {
let index = u32::decode(d)?;
let krate = CrateNum::decode(d)?;
let context = get_context(krate);
// Do this after decoding, so that we decode a `CrateNum`
// if necessary
@ -1152,18 +1150,14 @@ pub fn decode_expn_id<'a, D: Decoder>(
return Ok(ExpnId::root());
}
let outer_expns = &context.remapped_expns;
// Ensure that the lock() temporary is dropped early
{
if let Some(expn_id) = outer_expns.lock().get(index as usize).copied().flatten() {
return Ok(expn_id);
}
}
// This function is used to decode metadata, so it cannot decode information about LOCAL_CRATE.
debug_assert_ne!(krate, LOCAL_CRATE);
// Don't decode the data inside `HygieneData::with`, since we need to recursively decode
// other ExpnIds
let (mut expn_data, hash) = decode_data(d, index)?;
let (expn_data, hash) = decode_data(krate, index);
debug_assert_eq!(krate, expn_data.krate);
debug_assert_eq!(expn_data.orig_id, Some(index));
let expn_id = HygieneData::with(|hygiene_data| {
if let Some(&expn_id) = hygiene_data.expn_hash_to_expn_id.get(&hash) {
@ -1171,30 +1165,14 @@ pub fn decode_expn_id<'a, D: Decoder>(
}
let expn_id = ExpnId(hygiene_data.expn_data.len() as u32);
// If we just deserialized an `ExpnData` owned by
// the local crate, its `orig_id` will be stale,
// so we need to update it to its own value.
// This only happens when we deserialize the incremental cache,
// since a crate will never decode its own metadata.
if expn_data.krate == LOCAL_CRATE {
expn_data.orig_id = Some(expn_id.0);
}
hygiene_data.expn_data.push(Some(expn_data));
hygiene_data.expn_hashes.push(hash);
let _old_id = hygiene_data.expn_hash_to_expn_id.insert(hash, expn_id);
debug_assert!(_old_id.is_none());
let mut expns = outer_expns.lock();
let new_len = index as usize + 1;
if expns.len() < new_len {
expns.resize(new_len, None);
}
expns[index as usize] = Some(expn_id);
drop(expns);
expn_id
});
Ok(expn_id)
}