bjoernager/rust
bjoernager/rust
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Unify SourceFile::name_hash and StableSourceFileId

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This commit is contained in:
Michael Woerister 2023-12-19 22:34:26 +01:00
parent be69926a73
commit fa8ef25372
10 changed files with 131 additions and 118 deletions
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55
compiler/rustc_span/src/source_map.rs
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@ -13,7 +13,6 @@ use crate::*;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::sync::{IntoDynSyncSend, MappedReadGuard, ReadGuard, RwLock};
use std::fs;
use std::hash::Hash;
use std::io::{self, BorrowedBuf, Read};
use std::path::{self};
@ -152,45 +151,6 @@ impl FileLoader for RealFileLoader {
}
}
/// This is a [SourceFile] identifier that is used to correlate source files between
/// subsequent compilation sessions (which is something we need to do during
/// incremental compilation).
///
/// The [StableSourceFileId] also contains the CrateNum of the crate the source
/// file was originally parsed for. This way we get two separate entries in
/// the [SourceMap] if the same file is part of both the local and an upstream
/// crate. Trying to only have one entry for both cases is problematic because
/// at the point where we discover that there's a local use of the file in
/// addition to the upstream one, we might already have made decisions based on
/// the assumption that it's an upstream file. Treating the two files as
/// different has no real downsides.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
pub struct StableSourceFileId {
/// A hash of the source file's [`FileName`]. This is hash so that it's size
/// is more predictable than if we included the actual [`FileName`] value.
pub file_name_hash: Hash64,
/// The [`CrateNum`] of the crate this source file was originally parsed for.
/// We cannot include this information in the hash because at the time
/// of hashing we don't have the context to map from the [`CrateNum`]'s numeric
/// value to a `StableCrateId`.
pub cnum: CrateNum,
}
// FIXME: we need a more globally consistent approach to the problem solved by
// StableSourceFileId, perhaps built atop source_file.name_hash.
impl StableSourceFileId {
pub fn new(source_file: &SourceFile) -> StableSourceFileId {
StableSourceFileId::new_from_name(&source_file.name, source_file.cnum)
}
fn new_from_name(name: &FileName, cnum: CrateNum) -> StableSourceFileId {
let mut hasher = StableHasher::new();
name.hash(&mut hasher);
StableSourceFileId { file_name_hash: hasher.finish(), cnum }
}
}
// _____________________________________________________________________________
// SourceMap
//
@ -320,17 +280,17 @@ impl SourceMap {
// be empty, so the working directory will be used.
let (filename, _) = self.path_mapping.map_filename_prefix(&filename);
let file_id = StableSourceFileId::new_from_name(&filename, LOCAL_CRATE);
match self.source_file_by_stable_id(file_id) {
let stable_id = StableSourceFileId::from_filename_in_current_crate(&filename);
match self.source_file_by_stable_id(stable_id) {
Some(lrc_sf) => Ok(lrc_sf),
None => {
let source_file = SourceFile::new(filename, src, self.hash_kind)?;
// Let's make sure the file_id we generated above actually matches
// the ID we generate for the SourceFile we just created.
debug_assert_eq!(StableSourceFileId::new(&source_file), file_id);
debug_assert_eq!(source_file.stable_id, stable_id);
self.register_source_file(file_id, source_file)
self.register_source_file(stable_id, source_file)
}
}
}
@ -343,7 +303,7 @@ impl SourceMap {
&self,
filename: FileName,
src_hash: SourceFileHash,
name_hash: Hash128,
stable_id: StableSourceFileId,
source_len: u32,
cnum: CrateNum,
file_local_lines: FreezeLock<SourceFileLines>,
@ -368,12 +328,11 @@ impl SourceMap {
multibyte_chars,
non_narrow_chars,
normalized_pos,
name_hash,
stable_id,
cnum,
};
let file_id = StableSourceFileId::new(&source_file);
self.register_source_file(file_id, source_file)
self.register_source_file(stable_id, source_file)
.expect("not enough address space for imported source file")
}