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Auto merge of rust-lang#87393 - michaelwoerister:backport-85834-and-8…
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…6368, r=Mark-Simulacrum

Backport rust-lang#85834 and rust-lang#86368

As per discussion in https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/backport.20.2386368, backporting rust-lang#85834 too seems like the safest option for cleanly backporting rust-lang#86368.

r? `@Mark-Simulacrum`
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bors committed Jul 23, 2021
2 parents b959328 + 741e208 commit c8fb0b5
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Showing 7 changed files with 129 additions and 86 deletions.
8 changes: 4 additions & 4 deletions compiler/rustc_metadata/src/rmeta/decoder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -252,6 +252,10 @@ impl<'a, 'tcx> DecodeContext<'a, 'tcx> {
self.cdata.expect("missing CrateMetadata in DecodeContext")
}

fn map_encoded_cnum_to_current(&self, cnum: CrateNum) -> CrateNum {
if cnum == LOCAL_CRATE { self.cdata().cnum } else { self.cdata().cnum_map[cnum] }
}

fn read_lazy_with_meta<T: ?Sized + LazyMeta>(
&mut self,
meta: T::Meta,
Expand Down Expand Up @@ -324,10 +328,6 @@ impl<'a, 'tcx> TyDecoder<'tcx> for DecodeContext<'a, 'tcx> {
r
}

fn map_encoded_cnum_to_current(&self, cnum: CrateNum) -> CrateNum {
if cnum == LOCAL_CRATE { self.cdata().cnum } else { self.cdata().cnum_map[cnum] }
}

fn decode_alloc_id(&mut self) -> Result<rustc_middle::mir::interpret::AllocId, Self::Error> {
if let Some(alloc_decoding_session) = self.alloc_decoding_session {
alloc_decoding_session.decode_alloc_id(self)
Expand Down
4 changes: 1 addition & 3 deletions compiler/rustc_middle/src/ty/codec.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ use crate::mir::{
use crate::ty::subst::SubstsRef;
use crate::ty::{self, List, Ty, TyCtxt};
use rustc_data_structures::fx::FxHashMap;
use rustc_hir::def_id::{CrateNum, DefId};
use rustc_hir::def_id::DefId;
use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
use rustc_span::Span;
use std::hash::Hash;
Expand Down Expand Up @@ -179,8 +179,6 @@ pub trait TyDecoder<'tcx>: Decoder {
where
F: FnOnce(&mut Self) -> R;

fn map_encoded_cnum_to_current(&self, cnum: CrateNum) -> CrateNum;

fn positioned_at_shorthand(&self) -> bool {
(self.peek_byte() & (SHORTHAND_OFFSET as u8)) != 0
}
Expand Down
6 changes: 6 additions & 0 deletions compiler/rustc_middle/src/ty/context.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,7 @@ use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
use rustc_session::config::{BorrowckMode, CrateType, OutputFilenames};
use rustc_session::lint::{Level, Lint};
use rustc_session::Session;
use rustc_span::def_id::StableCrateId;
use rustc_span::source_map::MultiSpan;
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{Span, DUMMY_SP};
Expand Down Expand Up @@ -1264,6 +1265,11 @@ impl<'tcx> TyCtxt<'tcx> {
}
}

#[inline]
pub fn stable_crate_id(self, cnum: CrateNum) -> StableCrateId {
self.def_path_hash(cnum.as_def_id()).stable_crate_id()
}

pub fn def_path_debug_str(self, def_id: DefId) -> String {
// We are explicitly not going through queries here in order to get
// crate name and disambiguator since this code is called from debug!()
Expand Down
131 changes: 62 additions & 69 deletions compiler/rustc_middle/src/ty/query/on_disk_cache.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ use rustc_data_structures::sync::{HashMapExt, Lock, Lrc, OnceCell};
use rustc_data_structures::thin_vec::ThinVec;
use rustc_data_structures::unhash::UnhashMap;
use rustc_errors::Diagnostic;
use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LocalDefId, LOCAL_CRATE};
use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LocalDefId, StableCrateId, LOCAL_CRATE};
use rustc_hir::definitions::DefPathHash;
use rustc_index::vec::{Idx, IndexVec};
use rustc_query_system::dep_graph::DepContext;
Expand All @@ -18,7 +18,7 @@ use rustc_serialize::{
opaque::{self, FileEncodeResult, FileEncoder, IntEncodedWithFixedSize},
Decodable, Decoder, Encodable, Encoder,
};
use rustc_session::{CrateDisambiguator, Session};
use rustc_session::Session;
use rustc_span::hygiene::{
ExpnDataDecodeMode, ExpnDataEncodeMode, ExpnId, HygieneDecodeContext, HygieneEncodeContext,
SyntaxContext, SyntaxContextData,
Expand Down Expand Up @@ -51,11 +51,10 @@ pub struct OnDiskCache<'sess> {
// session.
current_diagnostics: Lock<FxHashMap<DepNodeIndex, Vec<Diagnostic>>>,

prev_cnums: Vec<(u32, String, CrateDisambiguator)>,
cnum_map: OnceCell<IndexVec<CrateNum, Option<CrateNum>>>,
cnum_map: OnceCell<UnhashMap<StableCrateId, CrateNum>>,

source_map: &'sess SourceMap,
file_index_to_stable_id: FxHashMap<SourceFileIndex, StableSourceFileId>,
file_index_to_stable_id: FxHashMap<SourceFileIndex, EncodedSourceFileId>,

// Caches that are populated lazily during decoding.
file_index_to_file: Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
Expand Down Expand Up @@ -112,8 +111,7 @@ pub struct OnDiskCache<'sess> {
// This type is used only for serialization and deserialization.
#[derive(Encodable, Decodable)]
struct Footer {
file_index_to_stable_id: FxHashMap<SourceFileIndex, StableSourceFileId>,
prev_cnums: Vec<(u32, String, CrateDisambiguator)>,
file_index_to_stable_id: FxHashMap<SourceFileIndex, EncodedSourceFileId>,
query_result_index: EncodedQueryResultIndex,
diagnostics_index: EncodedQueryResultIndex,
// The location of all allocations.
Expand Down Expand Up @@ -159,6 +157,32 @@ crate struct RawDefId {
pub index: u32,
}

/// An `EncodedSourceFileId` is the same as a `StableSourceFileId` except that
/// the source crate is represented as a [StableCrateId] instead of as a
/// `CrateNum`. This way `EncodedSourceFileId` can be encoded and decoded
/// without any additional context, i.e. with a simple `opaque::Decoder` (which
/// is the only thing available when decoding the cache's [Footer].
#[derive(Encodable, Decodable, Clone, Debug)]
struct EncodedSourceFileId {
file_name_hash: u64,
stable_crate_id: StableCrateId,
}

impl EncodedSourceFileId {
fn translate(&self, cnum_map: &UnhashMap<StableCrateId, CrateNum>) -> StableSourceFileId {
let cnum = cnum_map[&self.stable_crate_id];
StableSourceFileId { file_name_hash: self.file_name_hash, cnum }
}

fn new(tcx: TyCtxt<'_>, file: &SourceFile) -> EncodedSourceFileId {
let source_file_id = StableSourceFileId::new(file);
EncodedSourceFileId {
file_name_hash: source_file_id.file_name_hash,
stable_crate_id: tcx.stable_crate_id(source_file_id.cnum),
}
}
}

impl<'sess> OnDiskCache<'sess> {
/// Creates a new `OnDiskCache` instance from the serialized data in `data`.
pub fn new(sess: &'sess Session, data: Vec<u8>, start_pos: usize) -> Self {
Expand Down Expand Up @@ -186,7 +210,6 @@ impl<'sess> OnDiskCache<'sess> {
serialized_data: data,
file_index_to_stable_id: footer.file_index_to_stable_id,
file_index_to_file: Default::default(),
prev_cnums: footer.prev_cnums,
cnum_map: OnceCell::new(),
source_map: sess.source_map(),
current_diagnostics: Default::default(),
Expand All @@ -207,7 +230,6 @@ impl<'sess> OnDiskCache<'sess> {
serialized_data: Vec::new(),
file_index_to_stable_id: Default::default(),
file_index_to_file: Default::default(),
prev_cnums: vec![],
cnum_map: OnceCell::new(),
source_map,
current_diagnostics: Default::default(),
Expand Down Expand Up @@ -242,7 +264,8 @@ impl<'sess> OnDiskCache<'sess> {
let index = SourceFileIndex(index as u32);
let file_ptr: *const SourceFile = &**file as *const _;
file_to_file_index.insert(file_ptr, index);
file_index_to_stable_id.insert(index, StableSourceFileId::new(&file));
let source_file_id = EncodedSourceFileId::new(tcx, &file);
file_index_to_stable_id.insert(index, source_file_id);
}

(file_to_file_index, file_index_to_stable_id)
Expand Down Expand Up @@ -327,16 +350,6 @@ impl<'sess> OnDiskCache<'sess> {
interpret_alloc_index
};

let sorted_cnums = sorted_cnums_including_local_crate(tcx);
let prev_cnums: Vec<_> = sorted_cnums
.iter()
.map(|&cnum| {
let crate_name = tcx.crate_name(cnum).to_string();
let crate_disambiguator = tcx.crate_disambiguator(cnum);
(cnum.as_u32(), crate_name, crate_disambiguator)
})
.collect();

let mut syntax_contexts = FxHashMap::default();
let mut expn_ids = FxHashMap::default();

Expand Down Expand Up @@ -368,7 +381,6 @@ impl<'sess> OnDiskCache<'sess> {
TAG_FILE_FOOTER,
&Footer {
file_index_to_stable_id,
prev_cnums,
query_result_index,
diagnostics_index,
interpret_alloc_index,
Expand All @@ -385,16 +397,7 @@ impl<'sess> OnDiskCache<'sess> {
// DO NOT WRITE ANYTHING TO THE ENCODER AFTER THIS POINT! The address
// of the footer must be the last thing in the data stream.

return Ok(());

fn sorted_cnums_including_local_crate(tcx: TyCtxt<'_>) -> Vec<CrateNum> {
let mut cnums = vec![LOCAL_CRATE];
cnums.extend_from_slice(tcx.crates());
cnums.sort_unstable();
// Just to be sure...
cnums.dedup();
cnums
}
Ok(())
})
}

Expand Down Expand Up @@ -429,12 +432,11 @@ impl<'sess> OnDiskCache<'sess> {
self.foreign_def_path_hashes.get(hash).copied()
}

fn try_remap_cnum(&self, tcx: TyCtxt<'_>, cnum: u32) -> Option<CrateNum> {
let cnum_map =
self.cnum_map.get_or_init(|| Self::compute_cnum_map(tcx, &self.prev_cnums[..]));
debug!("try_remap_cnum({}): cnum_map={:?}", cnum, cnum_map);
fn try_remap_cnum(&self, tcx: TyCtxt<'_>, stable_crate_id: StableCrateId) -> Option<CrateNum> {
let cnum_map = self.cnum_map.get_or_init(|| Self::compute_cnum_map(tcx));
debug!("try_remap_cnum({:?}): cnum_map={:?}", stable_crate_id, cnum_map);

cnum_map[CrateNum::from_u32(cnum)]
cnum_map.get(&stable_crate_id).copied()
}

pub(crate) fn store_foreign_def_id_hash(&self, def_id: DefId, hash: DefPathHash) {
Expand Down Expand Up @@ -533,8 +535,7 @@ impl<'sess> OnDiskCache<'sess> {
where
T: Decodable<CacheDecoder<'a, 'tcx>>,
{
let cnum_map =
self.cnum_map.get_or_init(|| Self::compute_cnum_map(tcx, &self.prev_cnums[..]));
let cnum_map = self.cnum_map.get_or_init(|| Self::compute_cnum_map(tcx));

let mut decoder = CacheDecoder {
tcx,
Expand All @@ -555,31 +556,16 @@ impl<'sess> OnDiskCache<'sess> {
// current-session-`CrateNum`. There might be `CrateNum`s from the previous
// `Session` that don't occur in the current one. For these, the mapping
// maps to None.
fn compute_cnum_map(
tcx: TyCtxt<'_>,
prev_cnums: &[(u32, String, CrateDisambiguator)],
) -> IndexVec<CrateNum, Option<CrateNum>> {
fn compute_cnum_map(tcx: TyCtxt<'_>) -> UnhashMap<StableCrateId, CrateNum> {
tcx.dep_graph.with_ignore(|| {
let current_cnums = tcx
.all_crate_nums(())
tcx.all_crate_nums(())
.iter()
.chain(std::iter::once(&LOCAL_CRATE))
.map(|&cnum| {
let crate_name = tcx.crate_name(cnum).to_string();
let crate_disambiguator = tcx.crate_disambiguator(cnum);
((crate_name, crate_disambiguator), cnum)
let hash = tcx.def_path_hash(cnum.as_def_id()).stable_crate_id();
(hash, cnum)
})
.collect::<FxHashMap<_, _>>();

let map_size = prev_cnums.iter().map(|&(cnum, ..)| cnum).max().unwrap_or(0) + 1;
let mut map = IndexVec::from_elem_n(None, map_size as usize);

for &(prev_cnum, ref crate_name, crate_disambiguator) in prev_cnums {
let key = (crate_name.clone(), crate_disambiguator);
map[CrateNum::from_u32(prev_cnum)] = current_cnums.get(&key).cloned();
}

map[LOCAL_CRATE] = Some(LOCAL_CRATE);
map
.collect()
})
}

Expand Down Expand Up @@ -612,7 +598,7 @@ impl<'sess> OnDiskCache<'sess> {
debug!("def_path_hash_to_def_id({:?}): raw_def_id = {:?}", hash, raw_def_id);
// If the owning crate no longer exists, the corresponding definition definitely
// no longer exists.
let krate = self.try_remap_cnum(tcx, raw_def_id.krate)?;
let krate = self.try_remap_cnum(tcx, hash.stable_crate_id())?;
debug!("def_path_hash_to_def_id({:?}): krate = {:?}", hash, krate);
// If our `DefPathHash` corresponded to a definition in the local crate,
// we should have either found it in `local_def_path_hash_to_def_id`, or
Expand Down Expand Up @@ -644,9 +630,9 @@ pub struct CacheDecoder<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
opaque: opaque::Decoder<'a>,
source_map: &'a SourceMap,
cnum_map: &'a IndexVec<CrateNum, Option<CrateNum>>,
cnum_map: &'a UnhashMap<StableCrateId, CrateNum>,
file_index_to_file: &'a Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
file_index_to_stable_id: &'a FxHashMap<SourceFileIndex, StableSourceFileId>,
file_index_to_stable_id: &'a FxHashMap<SourceFileIndex, EncodedSourceFileId>,
alloc_decoding_session: AllocDecodingSession<'a>,
syntax_contexts: &'a FxHashMap<u32, AbsoluteBytePos>,
expn_data: &'a FxHashMap<u32, AbsoluteBytePos>,
Expand All @@ -659,14 +645,15 @@ impl<'a, 'tcx> CacheDecoder<'a, 'tcx> {
ref file_index_to_file,
ref file_index_to_stable_id,
ref source_map,
ref cnum_map,
..
} = *self;

file_index_to_file
.borrow_mut()
.entry(index)
.or_insert_with(|| {
let stable_id = file_index_to_stable_id[&index];
let stable_id = file_index_to_stable_id[&index].translate(cnum_map);
source_map
.source_file_by_stable_id(stable_id)
.expect("failed to lookup `SourceFile` in new context")
Expand Down Expand Up @@ -765,10 +752,6 @@ impl<'a, 'tcx> TyDecoder<'tcx> for CacheDecoder<'a, 'tcx> {
r
}

fn map_encoded_cnum_to_current(&self, cnum: CrateNum) -> CrateNum {
self.cnum_map[cnum].unwrap_or_else(|| bug!("could not find new `CrateNum` for {:?}", cnum))
}

fn decode_alloc_id(&mut self) -> Result<interpret::AllocId, Self::Error> {
let alloc_decoding_session = self.alloc_decoding_session;
alloc_decoding_session.decode_alloc_id(self)
Expand Down Expand Up @@ -850,8 +833,9 @@ impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for Span {

impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for CrateNum {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
let cnum = CrateNum::from_u32(u32::decode(d)?);
Ok(d.map_encoded_cnum_to_current(cnum))
let stable_id = StableCrateId::decode(d)?;
let cnum = d.cnum_map[&stable_id];
Ok(cnum)
}
}

Expand Down Expand Up @@ -1061,6 +1045,15 @@ where
}
}

impl<'a, 'tcx, E> Encodable<CacheEncoder<'a, 'tcx, E>> for CrateNum
where
E: 'a + OpaqueEncoder,
{
fn encode(&self, s: &mut CacheEncoder<'a, 'tcx, E>) -> Result<(), E::Error> {
s.tcx.stable_crate_id(*self).encode(s)
}
}

impl<'a, 'tcx, E> Encodable<CacheEncoder<'a, 'tcx, E>> for DefId
where
E: 'a + OpaqueEncoder,
Expand Down
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