rust/compiler/rustc_query_impl/src/on_disk_cache.rs

1096 lines
40 KiB
Rust

use crate::QueryCtxt;
use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
use rustc_data_structures::memmap::Mmap;
use rustc_data_structures::sync::{HashMapExt, Lock, Lrc, RwLock};
use rustc_data_structures::unhash::UnhashMap;
use rustc_data_structures::unord::UnordSet;
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_middle::dep_graph::{DepNodeIndex, SerializedDepNodeIndex};
use rustc_middle::mir::interpret::{AllocDecodingSession, AllocDecodingState};
use rustc_middle::mir::{self, interpret};
use rustc_middle::ty::codec::{RefDecodable, TyDecoder, TyEncoder};
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_query_system::dep_graph::DepContext;
use rustc_query_system::query::{QueryCache, QuerySideEffects};
use rustc_serialize::{
opaque::{FileEncodeResult, FileEncoder, IntEncodedWithFixedSize, MemDecoder},
Decodable, Decoder, Encodable, Encoder,
};
use rustc_session::Session;
use rustc_span::hygiene::{
ExpnId, HygieneDecodeContext, HygieneEncodeContext, SyntaxContext, SyntaxContextData,
};
use rustc_span::source_map::{SourceMap, StableSourceFileId};
use rustc_span::{BytePos, ExpnData, ExpnHash, Pos, SourceFile, Span};
use rustc_span::{CachingSourceMapView, Symbol};
use std::collections::hash_map::Entry;
use std::io;
use std::mem;
const TAG_FILE_FOOTER: u128 = 0xC0FFEE_C0FFEE_C0FFEE_C0FFEE_C0FFEE;
// A normal span encoded with both location information and a `SyntaxContext`
const TAG_FULL_SPAN: u8 = 0;
// A partial span with no location information, encoded only with a `SyntaxContext`
const TAG_PARTIAL_SPAN: u8 = 1;
const TAG_RELATIVE_SPAN: u8 = 2;
const TAG_SYNTAX_CONTEXT: u8 = 0;
const TAG_EXPN_DATA: u8 = 1;
// Tags for encoding Symbol's
const SYMBOL_STR: u8 = 0;
const SYMBOL_OFFSET: u8 = 1;
const SYMBOL_PREINTERNED: u8 = 2;
/// Provides an interface to incremental compilation data cached from the
/// previous compilation session. This data will eventually include the results
/// of a few selected queries (like `typeck` and `mir_optimized`) and
/// any side effects that have been emitted during a query.
pub struct OnDiskCache<'sess> {
// The complete cache data in serialized form.
serialized_data: RwLock<Option<Mmap>>,
// Collects all `QuerySideEffects` created during the current compilation
// session.
current_side_effects: Lock<FxHashMap<DepNodeIndex, QuerySideEffects>>,
source_map: &'sess SourceMap,
file_index_to_stable_id: FxHashMap<SourceFileIndex, EncodedSourceFileId>,
// Caches that are populated lazily during decoding.
file_index_to_file: Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
// A map from dep-node to the position of the cached query result in
// `serialized_data`.
query_result_index: FxHashMap<SerializedDepNodeIndex, AbsoluteBytePos>,
// A map from dep-node to the position of any associated `QuerySideEffects` in
// `serialized_data`.
prev_side_effects_index: FxHashMap<SerializedDepNodeIndex, AbsoluteBytePos>,
alloc_decoding_state: AllocDecodingState,
// A map from syntax context ids to the position of their associated
// `SyntaxContextData`. We use a `u32` instead of a `SyntaxContext`
// to represent the fact that we are storing *encoded* ids. When we decode
// a `SyntaxContext`, a new id will be allocated from the global `HygieneData`,
// which will almost certainly be different than the serialized id.
syntax_contexts: FxHashMap<u32, AbsoluteBytePos>,
// A map from the `DefPathHash` of an `ExpnId` to the position
// of their associated `ExpnData`. Ideally, we would store a `DefId`,
// but we need to decode this before we've constructed a `TyCtxt` (which
// makes it difficult to decode a `DefId`).
// Note that these `DefPathHashes` correspond to both local and foreign
// `ExpnData` (e.g `ExpnData.krate` may not be `LOCAL_CRATE`). Alternatively,
// we could look up the `ExpnData` from the metadata of foreign crates,
// but it seemed easier to have `OnDiskCache` be independent of the `CStore`.
expn_data: UnhashMap<ExpnHash, AbsoluteBytePos>,
// Additional information used when decoding hygiene data.
hygiene_context: HygieneDecodeContext,
// Maps `ExpnHash`es to their raw value from the *previous*
// compilation session. This is used as an initial 'guess' when
// we try to map an `ExpnHash` to its value in the current
// compilation session.
foreign_expn_data: UnhashMap<ExpnHash, u32>,
}
// This type is used only for serialization and deserialization.
#[derive(Encodable, Decodable)]
struct Footer {
file_index_to_stable_id: FxHashMap<SourceFileIndex, EncodedSourceFileId>,
query_result_index: EncodedDepNodeIndex,
side_effects_index: EncodedDepNodeIndex,
// The location of all allocations.
interpret_alloc_index: Vec<u32>,
// See `OnDiskCache.syntax_contexts`
syntax_contexts: FxHashMap<u32, AbsoluteBytePos>,
// See `OnDiskCache.expn_data`
expn_data: UnhashMap<ExpnHash, AbsoluteBytePos>,
foreign_expn_data: UnhashMap<ExpnHash, u32>,
}
pub type EncodedDepNodeIndex = Vec<(SerializedDepNodeIndex, AbsoluteBytePos)>;
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Encodable, Decodable)]
struct SourceFileIndex(u32);
#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq, Encodable, Decodable)]
pub struct AbsoluteBytePos(u64);
impl AbsoluteBytePos {
fn new(pos: usize) -> AbsoluteBytePos {
AbsoluteBytePos(pos.try_into().expect("Incremental cache file size overflowed u64."))
}
fn to_usize(self) -> usize {
self.0 as usize
}
}
/// 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, tcx: TyCtxt<'_>) -> StableSourceFileId {
let cnum = tcx.stable_crate_id_to_crate_num(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> rustc_middle::ty::OnDiskCache<'sess> for OnDiskCache<'sess> {
/// Creates a new `OnDiskCache` instance from the serialized data in `data`.
fn new(sess: &'sess Session, data: Mmap, start_pos: usize) -> Self {
debug_assert!(sess.opts.incremental.is_some());
// Wrap in a scope so we can borrow `data`.
let footer: Footer = {
let mut decoder = MemDecoder::new(&data, start_pos);
// Decode the *position* of the footer, which can be found in the
// last 8 bytes of the file.
decoder.set_position(data.len() - IntEncodedWithFixedSize::ENCODED_SIZE);
let footer_pos = IntEncodedWithFixedSize::decode(&mut decoder).0 as usize;
// Decode the file footer, which contains all the lookup tables, etc.
decoder.set_position(footer_pos);
decode_tagged(&mut decoder, TAG_FILE_FOOTER)
};
Self {
serialized_data: RwLock::new(Some(data)),
file_index_to_stable_id: footer.file_index_to_stable_id,
file_index_to_file: Default::default(),
source_map: sess.source_map(),
current_side_effects: Default::default(),
query_result_index: footer.query_result_index.into_iter().collect(),
prev_side_effects_index: footer.side_effects_index.into_iter().collect(),
alloc_decoding_state: AllocDecodingState::new(footer.interpret_alloc_index),
syntax_contexts: footer.syntax_contexts,
expn_data: footer.expn_data,
foreign_expn_data: footer.foreign_expn_data,
hygiene_context: Default::default(),
}
}
fn new_empty(source_map: &'sess SourceMap) -> Self {
Self {
serialized_data: RwLock::new(None),
file_index_to_stable_id: Default::default(),
file_index_to_file: Default::default(),
source_map,
current_side_effects: Default::default(),
query_result_index: Default::default(),
prev_side_effects_index: Default::default(),
alloc_decoding_state: AllocDecodingState::new(Vec::new()),
syntax_contexts: FxHashMap::default(),
expn_data: UnhashMap::default(),
foreign_expn_data: UnhashMap::default(),
hygiene_context: Default::default(),
}
}
/// Execute all cache promotions and release the serialized backing Mmap.
///
/// Cache promotions require invoking queries, which needs to read the serialized data.
/// In order to serialize the new on-disk cache, the former on-disk cache file needs to be
/// deleted, hence we won't be able to refer to its memmapped data.
fn drop_serialized_data(&self, tcx: TyCtxt<'_>) {
// Load everything into memory so we can write it out to the on-disk
// cache. The vast majority of cacheable query results should already
// be in memory, so this should be a cheap operation.
// Do this *before* we clone 'latest_foreign_def_path_hashes', since
// loading existing queries may cause us to create new DepNodes, which
// may in turn end up invoking `store_foreign_def_id_hash`
tcx.dep_graph.exec_cache_promotions(tcx);
*self.serialized_data.write() = None;
}
fn serialize(&self, tcx: TyCtxt<'_>, encoder: FileEncoder) -> FileEncodeResult {
// Serializing the `DepGraph` should not modify it.
tcx.dep_graph.with_ignore(|| {
// Allocate `SourceFileIndex`es.
let (file_to_file_index, file_index_to_stable_id) = {
let files = tcx.sess.source_map().files();
let mut file_to_file_index =
FxHashMap::with_capacity_and_hasher(files.len(), Default::default());
let mut file_index_to_stable_id =
FxHashMap::with_capacity_and_hasher(files.len(), Default::default());
for (index, file) in files.iter().enumerate() {
let index = SourceFileIndex(index as u32);
let file_ptr: *const SourceFile = &**file as *const _;
file_to_file_index.insert(file_ptr, index);
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)
};
let hygiene_encode_context = HygieneEncodeContext::default();
let mut encoder = CacheEncoder {
tcx,
encoder,
type_shorthands: Default::default(),
predicate_shorthands: Default::default(),
interpret_allocs: Default::default(),
source_map: CachingSourceMapView::new(tcx.sess.source_map()),
file_to_file_index,
hygiene_context: &hygiene_encode_context,
symbol_table: Default::default(),
};
// Encode query results.
let mut query_result_index = EncodedDepNodeIndex::new();
tcx.sess.time("encode_query_results", || {
let enc = &mut encoder;
let qri = &mut query_result_index;
QueryCtxt::from_tcx(tcx).encode_query_results(enc, qri);
});
// Encode side effects.
let side_effects_index: EncodedDepNodeIndex = self
.current_side_effects
.borrow()
.iter()
.map(|(dep_node_index, side_effects)| {
let pos = AbsoluteBytePos::new(encoder.position());
let dep_node_index = SerializedDepNodeIndex::new(dep_node_index.index());
encoder.encode_tagged(dep_node_index, side_effects);
(dep_node_index, pos)
})
.collect();
let interpret_alloc_index = {
let mut interpret_alloc_index = Vec::new();
let mut n = 0;
loop {
let new_n = encoder.interpret_allocs.len();
// If we have found new IDs, serialize those too.
if n == new_n {
// Otherwise, abort.
break;
}
interpret_alloc_index.reserve(new_n - n);
for idx in n..new_n {
let id = encoder.interpret_allocs[idx];
let pos = encoder.position() as u32;
interpret_alloc_index.push(pos);
interpret::specialized_encode_alloc_id(&mut encoder, tcx, id);
}
n = new_n;
}
interpret_alloc_index
};
let mut syntax_contexts = FxHashMap::default();
let mut expn_data = UnhashMap::default();
let mut foreign_expn_data = UnhashMap::default();
// Encode all hygiene data (`SyntaxContextData` and `ExpnData`) from the current
// session.
hygiene_encode_context.encode(
&mut encoder,
|encoder, index, ctxt_data| {
let pos = AbsoluteBytePos::new(encoder.position());
encoder.encode_tagged(TAG_SYNTAX_CONTEXT, ctxt_data);
syntax_contexts.insert(index, pos);
},
|encoder, expn_id, data, hash| {
if expn_id.krate == LOCAL_CRATE {
let pos = AbsoluteBytePos::new(encoder.position());
encoder.encode_tagged(TAG_EXPN_DATA, data);
expn_data.insert(hash, pos);
} else {
foreign_expn_data.insert(hash, expn_id.local_id.as_u32());
}
},
);
// Encode the file footer.
let footer_pos = encoder.position() as u64;
encoder.encode_tagged(
TAG_FILE_FOOTER,
&Footer {
file_index_to_stable_id,
query_result_index,
side_effects_index,
interpret_alloc_index,
syntax_contexts,
expn_data,
foreign_expn_data,
},
);
// Encode the position of the footer as the last 8 bytes of the
// file so we know where to look for it.
IntEncodedWithFixedSize(footer_pos).encode(&mut encoder.encoder);
// DO NOT WRITE ANYTHING TO THE ENCODER AFTER THIS POINT! The address
// of the footer must be the last thing in the data stream.
encoder.finish()
})
}
}
impl<'sess> OnDiskCache<'sess> {
pub fn as_dyn(&self) -> &dyn rustc_middle::ty::OnDiskCache<'sess> {
self as _
}
/// Loads a `QuerySideEffects` created during the previous compilation session.
pub fn load_side_effects(
&self,
tcx: TyCtxt<'_>,
dep_node_index: SerializedDepNodeIndex,
) -> QuerySideEffects {
let side_effects: Option<QuerySideEffects> =
self.load_indexed(tcx, dep_node_index, &self.prev_side_effects_index);
side_effects.unwrap_or_default()
}
/// Stores a `QuerySideEffects` emitted during the current compilation session.
/// Anything stored like this will be available via `load_side_effects` in
/// the next compilation session.
#[inline(never)]
#[cold]
pub fn store_side_effects(&self, dep_node_index: DepNodeIndex, side_effects: QuerySideEffects) {
let mut current_side_effects = self.current_side_effects.borrow_mut();
let prev = current_side_effects.insert(dep_node_index, side_effects);
debug_assert!(prev.is_none());
}
/// Return whether the cached query result can be decoded.
pub fn loadable_from_disk(&self, dep_node_index: SerializedDepNodeIndex) -> bool {
self.query_result_index.contains_key(&dep_node_index)
// with_decoder is infallible, so we can stop here
}
/// Returns the cached query result if there is something in the cache for
/// the given `SerializedDepNodeIndex`; otherwise returns `None`.
pub fn try_load_query_result<'tcx, T>(
&self,
tcx: TyCtxt<'tcx>,
dep_node_index: SerializedDepNodeIndex,
) -> Option<T>
where
T: for<'a> Decodable<CacheDecoder<'a, 'tcx>>,
{
let opt_value = self.load_indexed(tcx, dep_node_index, &self.query_result_index);
debug_assert_eq!(opt_value.is_some(), self.loadable_from_disk(dep_node_index));
opt_value
}
/// Stores side effect emitted during computation of an anonymous query.
/// Since many anonymous queries can share the same `DepNode`, we aggregate
/// them -- as opposed to regular queries where we assume that there is a
/// 1:1 relationship between query-key and `DepNode`.
#[inline(never)]
#[cold]
pub fn store_side_effects_for_anon_node(
&self,
dep_node_index: DepNodeIndex,
side_effects: QuerySideEffects,
) {
let mut current_side_effects = self.current_side_effects.borrow_mut();
let x = current_side_effects.entry(dep_node_index).or_default();
x.append(side_effects);
}
fn load_indexed<'tcx, T>(
&self,
tcx: TyCtxt<'tcx>,
dep_node_index: SerializedDepNodeIndex,
index: &FxHashMap<SerializedDepNodeIndex, AbsoluteBytePos>,
) -> Option<T>
where
T: for<'a> Decodable<CacheDecoder<'a, 'tcx>>,
{
let pos = index.get(&dep_node_index).cloned()?;
let value = self.with_decoder(tcx, pos, |decoder| decode_tagged(decoder, dep_node_index));
Some(value)
}
fn with_decoder<'a, 'tcx, T, F: for<'s> FnOnce(&mut CacheDecoder<'s, 'tcx>) -> T>(
&'sess self,
tcx: TyCtxt<'tcx>,
pos: AbsoluteBytePos,
f: F,
) -> T
where
T: Decodable<CacheDecoder<'a, 'tcx>>,
{
let serialized_data = self.serialized_data.read();
let mut decoder = CacheDecoder {
tcx,
opaque: MemDecoder::new(serialized_data.as_deref().unwrap_or(&[]), pos.to_usize()),
source_map: self.source_map,
file_index_to_file: &self.file_index_to_file,
file_index_to_stable_id: &self.file_index_to_stable_id,
alloc_decoding_session: self.alloc_decoding_state.new_decoding_session(),
syntax_contexts: &self.syntax_contexts,
expn_data: &self.expn_data,
foreign_expn_data: &self.foreign_expn_data,
hygiene_context: &self.hygiene_context,
};
f(&mut decoder)
}
}
//- DECODING -------------------------------------------------------------------
/// A decoder that can read from the incremental compilation cache. It is similar to the one
/// we use for crate metadata decoding in that it can rebase spans and eventually
/// will also handle things that contain `Ty` instances.
pub struct CacheDecoder<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
opaque: MemDecoder<'a>,
source_map: &'a SourceMap,
file_index_to_file: &'a Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
file_index_to_stable_id: &'a FxHashMap<SourceFileIndex, EncodedSourceFileId>,
alloc_decoding_session: AllocDecodingSession<'a>,
syntax_contexts: &'a FxHashMap<u32, AbsoluteBytePos>,
expn_data: &'a UnhashMap<ExpnHash, AbsoluteBytePos>,
foreign_expn_data: &'a UnhashMap<ExpnHash, u32>,
hygiene_context: &'a HygieneDecodeContext,
}
impl<'a, 'tcx> CacheDecoder<'a, 'tcx> {
fn file_index_to_file(&self, index: SourceFileIndex) -> Lrc<SourceFile> {
let CacheDecoder {
tcx,
ref file_index_to_file,
ref file_index_to_stable_id,
ref source_map,
..
} = *self;
file_index_to_file
.borrow_mut()
.entry(index)
.or_insert_with(|| {
let stable_id = file_index_to_stable_id[&index].translate(tcx);
// If this `SourceFile` is from a foreign crate, then make sure
// that we've imported all of the source files from that crate.
// This has usually already been done during macro invocation.
// However, when encoding query results like `TypeckResults`,
// we might encode an `AdtDef` for a foreign type (because it
// was referenced in the body of the function). There is no guarantee
// that we will load the source files from that crate during macro
// expansion, so we use `import_source_files` to ensure that the foreign
// source files are actually imported before we call `source_file_by_stable_id`.
if stable_id.cnum != LOCAL_CRATE {
self.tcx.cstore_untracked().import_source_files(self.tcx.sess, stable_id.cnum);
}
source_map
.source_file_by_stable_id(stable_id)
.expect("failed to lookup `SourceFile` in new context")
})
.clone()
}
}
trait DecoderWithPosition: Decoder {
fn position(&self) -> usize;
}
impl<'a> DecoderWithPosition for MemDecoder<'a> {
fn position(&self) -> usize {
self.position()
}
}
impl<'a, 'tcx> DecoderWithPosition for CacheDecoder<'a, 'tcx> {
fn position(&self) -> usize {
self.opaque.position()
}
}
// Decodes something that was encoded with `encode_tagged()` and verify that the
// tag matches and the correct amount of bytes was read.
fn decode_tagged<D, T, V>(decoder: &mut D, expected_tag: T) -> V
where
T: Decodable<D> + Eq + std::fmt::Debug,
V: Decodable<D>,
D: DecoderWithPosition,
{
let start_pos = decoder.position();
let actual_tag = T::decode(decoder);
assert_eq!(actual_tag, expected_tag);
let value = V::decode(decoder);
let end_pos = decoder.position();
let expected_len: u64 = Decodable::decode(decoder);
assert_eq!((end_pos - start_pos) as u64, expected_len);
value
}
impl<'a, 'tcx> TyDecoder for CacheDecoder<'a, 'tcx> {
type I = TyCtxt<'tcx>;
const CLEAR_CROSS_CRATE: bool = false;
#[inline]
fn interner(&self) -> TyCtxt<'tcx> {
self.tcx
}
#[inline]
fn position(&self) -> usize {
self.opaque.position()
}
#[inline]
fn peek_byte(&self) -> u8 {
self.opaque.data[self.opaque.position()]
}
fn cached_ty_for_shorthand<F>(&mut self, shorthand: usize, or_insert_with: F) -> Ty<'tcx>
where
F: FnOnce(&mut Self) -> Ty<'tcx>,
{
let tcx = self.tcx;
let cache_key = ty::CReaderCacheKey { cnum: None, pos: shorthand };
if let Some(&ty) = tcx.ty_rcache.borrow().get(&cache_key) {
return ty;
}
let ty = or_insert_with(self);
// This may overwrite the entry, but it should overwrite with the same value.
tcx.ty_rcache.borrow_mut().insert_same(cache_key, ty);
ty
}
fn with_position<F, R>(&mut self, pos: usize, f: F) -> R
where
F: FnOnce(&mut Self) -> R,
{
debug_assert!(pos < self.opaque.data.len());
let new_opaque = MemDecoder::new(self.opaque.data, pos);
let old_opaque = mem::replace(&mut self.opaque, new_opaque);
let r = f(self);
self.opaque = old_opaque;
r
}
fn decode_alloc_id(&mut self) -> interpret::AllocId {
let alloc_decoding_session = self.alloc_decoding_session;
alloc_decoding_session.decode_alloc_id(self)
}
}
rustc_middle::implement_ty_decoder!(CacheDecoder<'a, 'tcx>);
// This ensures that the `Decodable<opaque::Decoder>::decode` specialization for `Vec<u8>` is used
// when a `CacheDecoder` is passed to `Decodable::decode`. Unfortunately, we have to manually opt
// into specializations this way, given how `CacheDecoder` and the decoding traits currently work.
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for Vec<u8> {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
Decodable::decode(&mut d.opaque)
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for SyntaxContext {
fn decode(decoder: &mut CacheDecoder<'a, 'tcx>) -> Self {
let syntax_contexts = decoder.syntax_contexts;
rustc_span::hygiene::decode_syntax_context(decoder, decoder.hygiene_context, |this, id| {
// This closure is invoked if we haven't already decoded the data for the `SyntaxContext` we are deserializing.
// We look up the position of the associated `SyntaxData` and decode it.
let pos = syntax_contexts.get(&id).unwrap();
this.with_position(pos.to_usize(), |decoder| {
let data: SyntaxContextData = decode_tagged(decoder, TAG_SYNTAX_CONTEXT);
data
})
})
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for ExpnId {
fn decode(decoder: &mut CacheDecoder<'a, 'tcx>) -> Self {
let hash = ExpnHash::decode(decoder);
if hash.is_root() {
return ExpnId::root();
}
if let Some(expn_id) = ExpnId::from_hash(hash) {
return expn_id;
}
let krate = decoder.tcx.stable_crate_id_to_crate_num(hash.stable_crate_id());
let expn_id = if krate == LOCAL_CRATE {
// We look up the position of the associated `ExpnData` and decode it.
let pos = decoder
.expn_data
.get(&hash)
.unwrap_or_else(|| panic!("Bad hash {:?} (map {:?})", hash, decoder.expn_data));
let data: ExpnData = decoder
.with_position(pos.to_usize(), |decoder| decode_tagged(decoder, TAG_EXPN_DATA));
let expn_id = rustc_span::hygiene::register_local_expn_id(data, hash);
#[cfg(debug_assertions)]
{
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
let local_hash: u64 = decoder.tcx.with_stable_hashing_context(|mut hcx| {
let mut hasher = StableHasher::new();
expn_id.expn_data().hash_stable(&mut hcx, &mut hasher);
hasher.finish()
});
debug_assert_eq!(hash.local_hash(), local_hash);
}
expn_id
} else {
let index_guess = decoder.foreign_expn_data[&hash];
decoder.tcx.cstore_untracked().expn_hash_to_expn_id(
decoder.tcx.sess,
krate,
index_guess,
hash,
)
};
debug_assert_eq!(expn_id.krate, krate);
expn_id
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for Span {
fn decode(decoder: &mut CacheDecoder<'a, 'tcx>) -> Self {
let ctxt = SyntaxContext::decode(decoder);
let parent = Option::<LocalDefId>::decode(decoder);
let tag: u8 = Decodable::decode(decoder);
if tag == TAG_PARTIAL_SPAN {
return Span::new(BytePos(0), BytePos(0), ctxt, parent);
} else if tag == TAG_RELATIVE_SPAN {
let dlo = u32::decode(decoder);
let dto = u32::decode(decoder);
let enclosing = decoder.tcx.source_span_untracked(parent.unwrap()).data_untracked();
let span = Span::new(
enclosing.lo + BytePos::from_u32(dlo),
enclosing.lo + BytePos::from_u32(dto),
ctxt,
parent,
);
return span;
} else {
debug_assert_eq!(tag, TAG_FULL_SPAN);
}
let file_lo_index = SourceFileIndex::decode(decoder);
let line_lo = usize::decode(decoder);
let col_lo = BytePos::decode(decoder);
let len = BytePos::decode(decoder);
let file_lo = decoder.file_index_to_file(file_lo_index);
let lo = file_lo.lines(|lines| lines[line_lo - 1] + col_lo);
let hi = lo + len;
Span::new(lo, hi, ctxt, parent)
}
}
// copy&paste impl from rustc_metadata
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for Symbol {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
let tag = d.read_u8();
match tag {
SYMBOL_STR => {
let s = d.read_str();
Symbol::intern(s)
}
SYMBOL_OFFSET => {
// read str offset
let pos = d.read_usize();
let old_pos = d.opaque.position();
// move to str ofset and read
d.opaque.set_position(pos);
let s = d.read_str();
let sym = Symbol::intern(s);
// restore position
d.opaque.set_position(old_pos);
sym
}
SYMBOL_PREINTERNED => {
let symbol_index = d.read_u32();
Symbol::new_from_decoded(symbol_index)
}
_ => unreachable!(),
}
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for CrateNum {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
let stable_id = StableCrateId::decode(d);
let cnum = d.tcx.stable_crate_id_to_crate_num(stable_id);
cnum
}
}
// This impl makes sure that we get a runtime error when we try decode a
// `DefIndex` that is not contained in a `DefId`. Such a case would be problematic
// because we would not know how to transform the `DefIndex` to the current
// context.
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for DefIndex {
fn decode(_d: &mut CacheDecoder<'a, 'tcx>) -> DefIndex {
panic!("trying to decode `DefIndex` outside the context of a `DefId`")
}
}
// Both the `CrateNum` and the `DefIndex` of a `DefId` can change in between two
// compilation sessions. We use the `DefPathHash`, which is stable across
// sessions, to map the old `DefId` to the new one.
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for DefId {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
// Load the `DefPathHash` which is was we encoded the `DefId` as.
let def_path_hash = DefPathHash::decode(d);
// Using the `DefPathHash`, we can lookup the new `DefId`.
// Subtle: We only encode a `DefId` as part of a query result.
// If we get to this point, then all of the query inputs were green,
// which means that the definition with this hash is guaranteed to
// still exist in the current compilation session.
d.tcx.def_path_hash_to_def_id(def_path_hash, &mut || {
panic!("Failed to convert DefPathHash {def_path_hash:?}")
})
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx UnordSet<LocalDefId> {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
RefDecodable::decode(d)
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx FxHashMap<DefId, Ty<'tcx>> {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
RefDecodable::decode(d)
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>>
for &'tcx IndexVec<mir::Promoted, mir::Body<'tcx>>
{
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
RefDecodable::decode(d)
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [(ty::Predicate<'tcx>, Span)] {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
RefDecodable::decode(d)
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [(ty::Clause<'tcx>, Span)] {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
RefDecodable::decode(d)
}
}
impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [rustc_ast::InlineAsmTemplatePiece] {
fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
RefDecodable::decode(d)
}
}
macro_rules! impl_ref_decoder {
(<$tcx:tt> $($ty:ty,)*) => {
$(impl<'a, $tcx> Decodable<CacheDecoder<'a, $tcx>> for &$tcx [$ty] {
fn decode(d: &mut CacheDecoder<'a, $tcx>) -> Self {
RefDecodable::decode(d)
}
})*
};
}
impl_ref_decoder! {<'tcx>
Span,
rustc_ast::Attribute,
rustc_span::symbol::Ident,
ty::Variance,
rustc_span::def_id::DefId,
rustc_span::def_id::LocalDefId,
(rustc_middle::middle::exported_symbols::ExportedSymbol<'tcx>, rustc_middle::middle::exported_symbols::SymbolExportInfo),
ty::DeducedParamAttrs,
}
//- ENCODING -------------------------------------------------------------------
/// An encoder that can write to the incremental compilation cache.
pub struct CacheEncoder<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
encoder: FileEncoder,
type_shorthands: FxHashMap<Ty<'tcx>, usize>,
predicate_shorthands: FxHashMap<ty::PredicateKind<'tcx>, usize>,
interpret_allocs: FxIndexSet<interpret::AllocId>,
source_map: CachingSourceMapView<'tcx>,
file_to_file_index: FxHashMap<*const SourceFile, SourceFileIndex>,
hygiene_context: &'a HygieneEncodeContext,
symbol_table: FxHashMap<Symbol, usize>,
}
impl<'a, 'tcx> CacheEncoder<'a, 'tcx> {
fn source_file_index(&mut self, source_file: Lrc<SourceFile>) -> SourceFileIndex {
self.file_to_file_index[&(&*source_file as *const SourceFile)]
}
/// Encode something with additional information that allows to do some
/// sanity checks when decoding the data again. This method will first
/// encode the specified tag, then the given value, then the number of
/// bytes taken up by tag and value. On decoding, we can then verify that
/// we get the expected tag and read the expected number of bytes.
fn encode_tagged<T: Encodable<Self>, V: Encodable<Self>>(&mut self, tag: T, value: &V) {
let start_pos = self.position();
tag.encode(self);
value.encode(self);
let end_pos = self.position();
((end_pos - start_pos) as u64).encode(self);
}
fn finish(self) -> Result<usize, io::Error> {
self.encoder.finish()
}
}
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for SyntaxContext {
fn encode(&self, s: &mut CacheEncoder<'a, 'tcx>) {
rustc_span::hygiene::raw_encode_syntax_context(*self, s.hygiene_context, s);
}
}
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for ExpnId {
fn encode(&self, s: &mut CacheEncoder<'a, 'tcx>) {
s.hygiene_context.schedule_expn_data_for_encoding(*self);
self.expn_hash().encode(s);
}
}
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for Span {
fn encode(&self, s: &mut CacheEncoder<'a, 'tcx>) {
let span_data = self.data_untracked();
span_data.ctxt.encode(s);
span_data.parent.encode(s);
if span_data.is_dummy() {
return TAG_PARTIAL_SPAN.encode(s);
}
if let Some(parent) = span_data.parent {
let enclosing = s.tcx.source_span(parent).data_untracked();
if enclosing.contains(span_data) {
TAG_RELATIVE_SPAN.encode(s);
(span_data.lo - enclosing.lo).to_u32().encode(s);
(span_data.hi - enclosing.lo).to_u32().encode(s);
return;
}
}
let pos = s.source_map.byte_pos_to_line_and_col(span_data.lo);
let partial_span = match &pos {
Some((file_lo, _, _)) => !file_lo.contains(span_data.hi),
None => true,
};
if partial_span {
return TAG_PARTIAL_SPAN.encode(s);
}
let (file_lo, line_lo, col_lo) = pos.unwrap();
let len = span_data.hi - span_data.lo;
let source_file_index = s.source_file_index(file_lo);
TAG_FULL_SPAN.encode(s);
source_file_index.encode(s);
line_lo.encode(s);
col_lo.encode(s);
len.encode(s);
}
}
// copy&paste impl from rustc_metadata
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for Symbol {
fn encode(&self, s: &mut CacheEncoder<'a, 'tcx>) {
// if symbol preinterned, emit tag and symbol index
if self.is_preinterned() {
s.encoder.emit_u8(SYMBOL_PREINTERNED);
s.encoder.emit_u32(self.as_u32());
} else {
// otherwise write it as string or as offset to it
match s.symbol_table.entry(*self) {
Entry::Vacant(o) => {
s.encoder.emit_u8(SYMBOL_STR);
let pos = s.encoder.position();
o.insert(pos);
s.emit_str(self.as_str());
}
Entry::Occupied(o) => {
let x = *o.get();
s.emit_u8(SYMBOL_OFFSET);
s.emit_usize(x);
}
}
}
}
}
impl<'a, 'tcx> TyEncoder for CacheEncoder<'a, 'tcx> {
type I = TyCtxt<'tcx>;
const CLEAR_CROSS_CRATE: bool = false;
fn position(&self) -> usize {
self.encoder.position()
}
fn type_shorthands(&mut self) -> &mut FxHashMap<Ty<'tcx>, usize> {
&mut self.type_shorthands
}
fn predicate_shorthands(&mut self) -> &mut FxHashMap<ty::PredicateKind<'tcx>, usize> {
&mut self.predicate_shorthands
}
fn encode_alloc_id(&mut self, alloc_id: &interpret::AllocId) {
let (index, _) = self.interpret_allocs.insert_full(*alloc_id);
index.encode(self);
}
}
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for CrateNum {
fn encode(&self, s: &mut CacheEncoder<'a, 'tcx>) {
s.tcx.stable_crate_id(*self).encode(s);
}
}
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for DefId {
fn encode(&self, s: &mut CacheEncoder<'a, 'tcx>) {
s.tcx.def_path_hash(*self).encode(s);
}
}
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for DefIndex {
fn encode(&self, _: &mut CacheEncoder<'a, 'tcx>) {
bug!("encoding `DefIndex` without context");
}
}
macro_rules! encoder_methods {
($($name:ident($ty:ty);)*) => {
#[inline]
$(fn $name(&mut self, value: $ty) {
self.encoder.$name(value)
})*
}
}
impl<'a, 'tcx> Encoder for CacheEncoder<'a, 'tcx> {
encoder_methods! {
emit_usize(usize);
emit_u128(u128);
emit_u64(u64);
emit_u32(u32);
emit_u16(u16);
emit_u8(u8);
emit_isize(isize);
emit_i128(i128);
emit_i64(i64);
emit_i32(i32);
emit_i16(i16);
emit_i8(i8);
emit_bool(bool);
emit_f64(f64);
emit_f32(f32);
emit_char(char);
emit_str(&str);
emit_raw_bytes(&[u8]);
}
}
// This ensures that the `Encodable<opaque::FileEncoder>::encode` specialization for byte slices
// is used when a `CacheEncoder` having an `opaque::FileEncoder` is passed to `Encodable::encode`.
// Unfortunately, we have to manually opt into specializations this way, given how `CacheEncoder`
// and the encoding traits currently work.
impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx>> for [u8] {
fn encode(&self, e: &mut CacheEncoder<'a, 'tcx>) {
self.encode(&mut e.encoder);
}
}
pub fn encode_query_results<'a, 'tcx, Q>(
query: Q,
qcx: QueryCtxt<'tcx>,
encoder: &mut CacheEncoder<'a, 'tcx>,
query_result_index: &mut EncodedDepNodeIndex,
) where
Q: super::QueryConfig<QueryCtxt<'tcx>>,
Q::Value: Encodable<CacheEncoder<'a, 'tcx>>,
{
let _timer = qcx
.tcx
.profiler()
.verbose_generic_activity_with_arg("encode_query_results_for", query.name());
assert!(query.query_state(qcx).all_inactive());
let cache = query.query_cache(qcx);
cache.iter(&mut |key, value, dep_node| {
if query.cache_on_disk(qcx.tcx, &key) {
let dep_node = SerializedDepNodeIndex::new(dep_node.index());
// Record position of the cache entry.
query_result_index.push((dep_node, AbsoluteBytePos::new(encoder.encoder.position())));
// Encode the type check tables with the `SerializedDepNodeIndex`
// as tag.
encoder.encode_tagged(dep_node, value);
}
});
}