bjoernager/rust
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Directly encode DefPathHash in metadata.

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This commit is contained in:
Camille GILLOT 2022-04-10 11:14:58 +02:00
parent 72be5b81df
commit 6142f50845
4 changed files with 25 additions and 7 deletions
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6
compiler/rustc_metadata/src/rmeta/decoder.rs
View file

@ -1459,9 +1459,9 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
index: DefIndex,
def_path_hashes: &mut FxHashMap<DefIndex, DefPathHash>,
) -> DefPathHash {
*def_path_hashes.entry(index).or_insert_with(|| {
self.root.tables.def_path_hashes.get(self, index).unwrap().decode(self)
})
*def_path_hashes
.entry(index)
.or_insert_with(|| self.root.tables.def_path_hashes.get(self, index).unwrap())
}
#[inline]

5
compiler/rustc_metadata/src/rmeta/encoder.rs
View file

@ -461,16 +461,15 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
.chain(self.tcx.resolutions(()).proc_macros.iter().map(|p| p.local_def_index))
{
let def_key = self.lazy(table.def_key(def_index));
let def_path_hash = self.lazy(table.def_path_hash(def_index));
let def_path_hash = table.def_path_hash(def_index);
self.tables.def_keys.set(def_index, def_key);
self.tables.def_path_hashes.set(def_index, def_path_hash);
}
} else {
for (def_index, def_key, def_path_hash) in table.enumerated_keys_and_path_hashes() {
let def_key = self.lazy(def_key);
let def_path_hash = self.lazy(def_path_hash);
self.tables.def_keys.set(def_index, def_key);
self.tables.def_path_hashes.set(def_index, def_path_hash);
self.tables.def_path_hashes.set(def_index, *def_path_hash);
}
}
}

2
compiler/rustc_metadata/src/rmeta/mod.rs
View file

@ -332,7 +332,7 @@ define_tables! {
// `DefPathTable` up front, since we may only ever use a few
// definitions from any given crate.
def_keys: Table<DefIndex, Lazy<DefKey>>,
def_path_hashes: Table<DefIndex, Lazy<DefPathHash>>,
def_path_hashes: Table<DefIndex, DefPathHash>,
proc_macro_quoted_spans: Table<usize, Lazy<Span>>,
}

19
compiler/rustc_metadata/src/rmeta/table.rs
View file

@ -1,5 +1,6 @@
use crate::rmeta::*;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_hir::def::{CtorKind, CtorOf};
use rustc_index::vec::Idx;
use rustc_serialize::opaque::Encoder;
@ -181,6 +182,24 @@ fixed_size_enum! {
}
}
// We directly encode `DefPathHash` because a `Lazy` would encur a 25% cost.
impl FixedSizeEncoding for Option<DefPathHash> {
fixed_size_encoding_byte_len_and_defaults!(16);
#[inline]
fn from_bytes(b: &[u8]) -> Self {
Some(DefPathHash(Fingerprint::from_le_bytes(b.try_into().unwrap())))
}
#[inline]
fn write_to_bytes(self, b: &mut [u8]) {
let Some(DefPathHash(fingerprint)) = self else {
panic!("Trying to encode absent DefPathHash.")
};
b[..Self::BYTE_LEN].copy_from_slice(&fingerprint.to_le_bytes());
}
}
// NOTE(eddyb) there could be an impl for `usize`, which would enable a more
// generic `Lazy<T>` impl, but in the general case we might not need / want to
// fit every `usize` in `u32`.