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49cdf06b4a
Allow overwriting ExpnId for concurrent decoding These assertions only hold for the single threaded compiler. They were triggered in https://github.com/rust-lang/rust/pull/115003.
1582 lines
59 KiB
Rust
1582 lines
59 KiB
Rust
//! Machinery for hygienic macros.
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//!
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//! Inspired by Matthew Flatt et al., “Macros That Work Together: Compile-Time Bindings, Partial
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//! Expansion, and Definition Contexts,” *Journal of Functional Programming* 22, no. 2
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//! (March 1, 2012): 181–216, <https://doi.org/10.1017/S0956796812000093>.
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// Hygiene data is stored in a global variable and accessed via TLS, which
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// means that accesses are somewhat expensive. (`HygieneData::with`
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// encapsulates a single access.) Therefore, on hot code paths it is worth
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// ensuring that multiple HygieneData accesses are combined into a single
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// `HygieneData::with`.
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//
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// This explains why `HygieneData`, `SyntaxContext` and `ExpnId` have interfaces
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// with a certain amount of redundancy in them. For example,
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// `SyntaxContext::outer_expn_data` combines `SyntaxContext::outer` and
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// `ExpnId::expn_data` so that two `HygieneData` accesses can be performed within
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// a single `HygieneData::with` call.
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//
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// It also explains why many functions appear in `HygieneData` and again in
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// `SyntaxContext` or `ExpnId`. For example, `HygieneData::outer` and
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// `SyntaxContext::outer` do the same thing, but the former is for use within a
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// `HygieneData::with` call while the latter is for use outside such a call.
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// When modifying this file it is important to understand this distinction,
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// because getting it wrong can lead to nested `HygieneData::with` calls that
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// trigger runtime aborts. (Fortunately these are obvious and easy to fix.)
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use crate::edition::Edition;
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use crate::symbol::{kw, sym, Symbol};
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use crate::with_session_globals;
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use crate::{HashStableContext, Span, DUMMY_SP};
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use crate::def_id::{CrateNum, DefId, StableCrateId, CRATE_DEF_ID, LOCAL_CRATE};
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use rustc_data_structures::fingerprint::Fingerprint;
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use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_data_structures::stable_hasher::HashingControls;
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use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
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use rustc_data_structures::sync::{Lock, Lrc, WorkerLocal};
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use rustc_data_structures::unhash::UnhashMap;
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use rustc_index::IndexVec;
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use rustc_macros::HashStable_Generic;
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use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
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use std::cell::RefCell;
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use std::collections::hash_map::Entry;
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use std::fmt;
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use std::hash::Hash;
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/// A `SyntaxContext` represents a chain of pairs `(ExpnId, Transparency)` named "marks".
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#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
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pub struct SyntaxContext(u32);
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#[derive(Debug, Encodable, Decodable, Clone)]
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pub struct SyntaxContextData {
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outer_expn: ExpnId,
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outer_transparency: Transparency,
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parent: SyntaxContext,
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/// This context, but with all transparent and semi-transparent expansions filtered away.
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opaque: SyntaxContext,
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/// This context, but with all transparent expansions filtered away.
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opaque_and_semitransparent: SyntaxContext,
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/// Name of the crate to which `$crate` with this context would resolve.
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dollar_crate_name: Symbol,
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}
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rustc_index::newtype_index! {
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/// A unique ID associated with a macro invocation and expansion.
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#[custom_encodable]
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pub struct ExpnIndex {}
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}
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/// A unique ID associated with a macro invocation and expansion.
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#[derive(Clone, Copy, PartialEq, Eq, Hash)]
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pub struct ExpnId {
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pub krate: CrateNum,
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pub local_id: ExpnIndex,
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}
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impl fmt::Debug for ExpnId {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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// Generate crate_::{{expn_}}.
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write!(f, "{:?}::{{{{expn{}}}}}", self.krate, self.local_id.as_u32())
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}
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}
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rustc_index::newtype_index! {
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/// A unique ID associated with a macro invocation and expansion.
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#[custom_encodable]
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#[no_ord_impl]
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#[debug_format = "expn{}"]
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pub struct LocalExpnId {}
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}
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// To ensure correctness of incremental compilation,
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// `LocalExpnId` must not implement `Ord` or `PartialOrd`.
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// See https://github.com/rust-lang/rust/issues/90317.
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impl !Ord for LocalExpnId {}
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impl !PartialOrd for LocalExpnId {}
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/// Assert that the provided `HashStableContext` is configured with the 'default'
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/// `HashingControls`. We should always have bailed out before getting to here
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/// with a non-default mode. With this check in place, we can avoid the need
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/// to maintain separate versions of `ExpnData` hashes for each permutation
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/// of `HashingControls` settings.
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fn assert_default_hashing_controls<CTX: HashStableContext>(ctx: &CTX, msg: &str) {
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match ctx.hashing_controls() {
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// Note that we require that `hash_spans` be set according to the global
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// `-Z incremental-ignore-spans` option. Normally, this option is disabled,
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// which will cause us to require that this method always be called with `Span` hashing
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// enabled.
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//
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// Span hashing can also be disabled without `-Z incremental-ignore-spans`.
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// This is the case for instance when building a hash for name mangling.
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// Such configuration must not be used for metadata.
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HashingControls { hash_spans }
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if hash_spans != ctx.unstable_opts_incremental_ignore_spans() => {}
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other => panic!("Attempted hashing of {msg} with non-default HashingControls: {other:?}"),
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}
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}
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/// A unique hash value associated to an expansion.
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#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, Encodable, Decodable, HashStable_Generic)]
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pub struct ExpnHash(Fingerprint);
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impl ExpnHash {
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/// Returns the [StableCrateId] identifying the crate this [ExpnHash]
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/// originates from.
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#[inline]
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pub fn stable_crate_id(self) -> StableCrateId {
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StableCrateId(self.0.split().0)
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}
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/// Returns the crate-local part of the [ExpnHash].
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///
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/// Used for tests.
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#[inline]
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pub fn local_hash(self) -> Hash64 {
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self.0.split().1
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}
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#[inline]
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pub fn is_root(self) -> bool {
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self.0 == Fingerprint::ZERO
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}
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/// Builds a new [ExpnHash] with the given [StableCrateId] and
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/// `local_hash`, where `local_hash` must be unique within its crate.
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fn new(stable_crate_id: StableCrateId, local_hash: Hash64) -> ExpnHash {
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ExpnHash(Fingerprint::new(stable_crate_id.0, local_hash))
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}
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}
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/// A property of a macro expansion that determines how identifiers
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/// produced by that expansion are resolved.
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#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Hash, Debug, Encodable, Decodable)]
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#[derive(HashStable_Generic)]
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pub enum Transparency {
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/// Identifier produced by a transparent expansion is always resolved at call-site.
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/// Call-site spans in procedural macros, hygiene opt-out in `macro` should use this.
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Transparent,
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/// Identifier produced by a semi-transparent expansion may be resolved
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/// either at call-site or at definition-site.
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/// If it's a local variable, label or `$crate` then it's resolved at def-site.
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/// Otherwise it's resolved at call-site.
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/// `macro_rules` macros behave like this, built-in macros currently behave like this too,
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/// but that's an implementation detail.
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SemiTransparent,
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/// Identifier produced by an opaque expansion is always resolved at definition-site.
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/// Def-site spans in procedural macros, identifiers from `macro` by default use this.
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Opaque,
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}
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impl LocalExpnId {
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/// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST.
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pub const ROOT: LocalExpnId = LocalExpnId::from_u32(0);
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#[inline]
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pub fn from_raw(idx: ExpnIndex) -> LocalExpnId {
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LocalExpnId::from_u32(idx.as_u32())
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}
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#[inline]
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pub fn as_raw(self) -> ExpnIndex {
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ExpnIndex::from_u32(self.as_u32())
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}
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pub fn fresh_empty() -> LocalExpnId {
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HygieneData::with(|data| {
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let expn_id = data.local_expn_data.push(None);
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let _eid = data.local_expn_hashes.push(ExpnHash(Fingerprint::ZERO));
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debug_assert_eq!(expn_id, _eid);
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expn_id
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})
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}
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pub fn fresh(mut expn_data: ExpnData, ctx: impl HashStableContext) -> LocalExpnId {
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debug_assert_eq!(expn_data.parent.krate, LOCAL_CRATE);
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let expn_hash = update_disambiguator(&mut expn_data, ctx);
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HygieneData::with(|data| {
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let expn_id = data.local_expn_data.push(Some(expn_data));
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let _eid = data.local_expn_hashes.push(expn_hash);
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debug_assert_eq!(expn_id, _eid);
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let _old_id = data.expn_hash_to_expn_id.insert(expn_hash, expn_id.to_expn_id());
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debug_assert!(_old_id.is_none());
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expn_id
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})
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}
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#[inline]
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pub fn expn_hash(self) -> ExpnHash {
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HygieneData::with(|data| data.local_expn_hash(self))
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}
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#[inline]
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pub fn expn_data(self) -> ExpnData {
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HygieneData::with(|data| data.local_expn_data(self).clone())
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}
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#[inline]
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pub fn to_expn_id(self) -> ExpnId {
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ExpnId { krate: LOCAL_CRATE, local_id: self.as_raw() }
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}
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#[inline]
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pub fn set_expn_data(self, mut expn_data: ExpnData, ctx: impl HashStableContext) {
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debug_assert_eq!(expn_data.parent.krate, LOCAL_CRATE);
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let expn_hash = update_disambiguator(&mut expn_data, ctx);
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HygieneData::with(|data| {
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let old_expn_data = &mut data.local_expn_data[self];
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assert!(old_expn_data.is_none(), "expansion data is reset for an expansion ID");
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*old_expn_data = Some(expn_data);
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debug_assert_eq!(data.local_expn_hashes[self].0, Fingerprint::ZERO);
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data.local_expn_hashes[self] = expn_hash;
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let _old_id = data.expn_hash_to_expn_id.insert(expn_hash, self.to_expn_id());
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debug_assert!(_old_id.is_none());
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});
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}
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#[inline]
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pub fn is_descendant_of(self, ancestor: LocalExpnId) -> bool {
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self.to_expn_id().is_descendant_of(ancestor.to_expn_id())
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}
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/// `expn_id.outer_expn_is_descendant_of(ctxt)` is equivalent to but faster than
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/// `expn_id.is_descendant_of(ctxt.outer_expn())`.
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#[inline]
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pub fn outer_expn_is_descendant_of(self, ctxt: SyntaxContext) -> bool {
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self.to_expn_id().outer_expn_is_descendant_of(ctxt)
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}
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/// Returns span for the macro which originally caused this expansion to happen.
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///
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/// Stops backtracing at include! boundary.
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#[inline]
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pub fn expansion_cause(self) -> Option<Span> {
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self.to_expn_id().expansion_cause()
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}
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#[inline]
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#[track_caller]
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pub fn parent(self) -> LocalExpnId {
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self.expn_data().parent.as_local().unwrap()
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}
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}
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impl ExpnId {
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/// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST.
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/// Invariant: we do not create any ExpnId with local_id == 0 and krate != 0.
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pub const fn root() -> ExpnId {
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ExpnId { krate: LOCAL_CRATE, local_id: ExpnIndex::from_u32(0) }
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}
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#[inline]
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pub fn expn_hash(self) -> ExpnHash {
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HygieneData::with(|data| data.expn_hash(self))
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}
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#[inline]
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pub fn from_hash(hash: ExpnHash) -> Option<ExpnId> {
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HygieneData::with(|data| data.expn_hash_to_expn_id.get(&hash).copied())
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}
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#[inline]
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pub fn as_local(self) -> Option<LocalExpnId> {
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if self.krate == LOCAL_CRATE { Some(LocalExpnId::from_raw(self.local_id)) } else { None }
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}
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#[inline]
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#[track_caller]
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pub fn expect_local(self) -> LocalExpnId {
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self.as_local().unwrap()
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}
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#[inline]
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pub fn expn_data(self) -> ExpnData {
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HygieneData::with(|data| data.expn_data(self).clone())
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}
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#[inline]
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pub fn is_descendant_of(self, ancestor: ExpnId) -> bool {
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// a few "fast path" cases to avoid locking HygieneData
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if ancestor == ExpnId::root() || ancestor == self {
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return true;
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}
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if ancestor.krate != self.krate {
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return false;
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}
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HygieneData::with(|data| data.is_descendant_of(self, ancestor))
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}
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/// `expn_id.outer_expn_is_descendant_of(ctxt)` is equivalent to but faster than
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/// `expn_id.is_descendant_of(ctxt.outer_expn())`.
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pub fn outer_expn_is_descendant_of(self, ctxt: SyntaxContext) -> bool {
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HygieneData::with(|data| data.is_descendant_of(self, data.outer_expn(ctxt)))
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}
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/// Returns span for the macro which originally caused this expansion to happen.
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///
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/// Stops backtracing at include! boundary.
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pub fn expansion_cause(mut self) -> Option<Span> {
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let mut last_macro = None;
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loop {
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let expn_data = self.expn_data();
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// Stop going up the backtrace once include! is encountered
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if expn_data.is_root()
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|| expn_data.kind == ExpnKind::Macro(MacroKind::Bang, sym::include)
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{
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break;
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}
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self = expn_data.call_site.ctxt().outer_expn();
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last_macro = Some(expn_data.call_site);
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}
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last_macro
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}
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}
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#[derive(Debug)]
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pub struct HygieneData {
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/// Each expansion should have an associated expansion data, but sometimes there's a delay
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/// between creation of an expansion ID and obtaining its data (e.g. macros are collected
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/// first and then resolved later), so we use an `Option` here.
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local_expn_data: IndexVec<LocalExpnId, Option<ExpnData>>,
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local_expn_hashes: IndexVec<LocalExpnId, ExpnHash>,
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/// Data and hash information from external crates. We may eventually want to remove these
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/// maps, and fetch the information directly from the other crate's metadata like DefIds do.
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foreign_expn_data: FxHashMap<ExpnId, ExpnData>,
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foreign_expn_hashes: FxHashMap<ExpnId, ExpnHash>,
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expn_hash_to_expn_id: UnhashMap<ExpnHash, ExpnId>,
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syntax_context_data: Vec<SyntaxContextData>,
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syntax_context_map: FxHashMap<(SyntaxContext, ExpnId, Transparency), SyntaxContext>,
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/// Maps the `local_hash` of an `ExpnData` to the next disambiguator value.
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/// This is used by `update_disambiguator` to keep track of which `ExpnData`s
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/// would have collisions without a disambiguator.
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/// The keys of this map are always computed with `ExpnData.disambiguator`
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/// set to 0.
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expn_data_disambiguators: FxHashMap<Hash64, u32>,
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}
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impl HygieneData {
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pub(crate) fn new(edition: Edition) -> Self {
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let root_data = ExpnData::default(
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ExpnKind::Root,
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DUMMY_SP,
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edition,
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Some(CRATE_DEF_ID.to_def_id()),
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None,
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);
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HygieneData {
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local_expn_data: IndexVec::from_elem_n(Some(root_data), 1),
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local_expn_hashes: IndexVec::from_elem_n(ExpnHash(Fingerprint::ZERO), 1),
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foreign_expn_data: FxHashMap::default(),
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foreign_expn_hashes: FxHashMap::default(),
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expn_hash_to_expn_id: std::iter::once((ExpnHash(Fingerprint::ZERO), ExpnId::root()))
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.collect(),
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syntax_context_data: vec![SyntaxContextData {
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outer_expn: ExpnId::root(),
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outer_transparency: Transparency::Opaque,
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parent: SyntaxContext(0),
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opaque: SyntaxContext(0),
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opaque_and_semitransparent: SyntaxContext(0),
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dollar_crate_name: kw::DollarCrate,
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}],
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syntax_context_map: FxHashMap::default(),
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expn_data_disambiguators: FxHashMap::default(),
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}
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}
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pub fn with<T, F: FnOnce(&mut HygieneData) -> T>(f: F) -> T {
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with_session_globals(|session_globals| f(&mut session_globals.hygiene_data.borrow_mut()))
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}
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#[inline]
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fn local_expn_hash(&self, expn_id: LocalExpnId) -> ExpnHash {
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self.local_expn_hashes[expn_id]
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}
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#[inline]
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fn expn_hash(&self, expn_id: ExpnId) -> ExpnHash {
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match expn_id.as_local() {
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Some(expn_id) => self.local_expn_hashes[expn_id],
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None => self.foreign_expn_hashes[&expn_id],
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}
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}
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fn local_expn_data(&self, expn_id: LocalExpnId) -> &ExpnData {
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self.local_expn_data[expn_id].as_ref().expect("no expansion data for an expansion ID")
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}
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fn expn_data(&self, expn_id: ExpnId) -> &ExpnData {
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if let Some(expn_id) = expn_id.as_local() {
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self.local_expn_data[expn_id].as_ref().expect("no expansion data for an expansion ID")
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} else {
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&self.foreign_expn_data[&expn_id]
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}
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}
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fn is_descendant_of(&self, mut expn_id: ExpnId, ancestor: ExpnId) -> bool {
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// a couple "fast path" cases to avoid traversing parents in the loop below
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if ancestor == ExpnId::root() {
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return true;
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}
|
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if expn_id.krate != ancestor.krate {
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return false;
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}
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loop {
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if expn_id == ancestor {
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return true;
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}
|
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if expn_id == ExpnId::root() {
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return false;
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}
|
||
expn_id = self.expn_data(expn_id).parent;
|
||
}
|
||
}
|
||
|
||
fn normalize_to_macros_2_0(&self, ctxt: SyntaxContext) -> SyntaxContext {
|
||
self.syntax_context_data[ctxt.0 as usize].opaque
|
||
}
|
||
|
||
fn normalize_to_macro_rules(&self, ctxt: SyntaxContext) -> SyntaxContext {
|
||
self.syntax_context_data[ctxt.0 as usize].opaque_and_semitransparent
|
||
}
|
||
|
||
fn outer_expn(&self, ctxt: SyntaxContext) -> ExpnId {
|
||
self.syntax_context_data[ctxt.0 as usize].outer_expn
|
||
}
|
||
|
||
fn outer_mark(&self, ctxt: SyntaxContext) -> (ExpnId, Transparency) {
|
||
let data = &self.syntax_context_data[ctxt.0 as usize];
|
||
(data.outer_expn, data.outer_transparency)
|
||
}
|
||
|
||
fn parent_ctxt(&self, ctxt: SyntaxContext) -> SyntaxContext {
|
||
self.syntax_context_data[ctxt.0 as usize].parent
|
||
}
|
||
|
||
fn remove_mark(&self, ctxt: &mut SyntaxContext) -> (ExpnId, Transparency) {
|
||
let outer_mark = self.outer_mark(*ctxt);
|
||
*ctxt = self.parent_ctxt(*ctxt);
|
||
outer_mark
|
||
}
|
||
|
||
fn marks(&self, mut ctxt: SyntaxContext) -> Vec<(ExpnId, Transparency)> {
|
||
let mut marks = Vec::new();
|
||
while ctxt != SyntaxContext::root() {
|
||
debug!("marks: getting parent of {:?}", ctxt);
|
||
marks.push(self.outer_mark(ctxt));
|
||
ctxt = self.parent_ctxt(ctxt);
|
||
}
|
||
marks.reverse();
|
||
marks
|
||
}
|
||
|
||
fn walk_chain(&self, mut span: Span, to: SyntaxContext) -> Span {
|
||
debug!("walk_chain({:?}, {:?})", span, to);
|
||
debug!("walk_chain: span ctxt = {:?}", span.ctxt());
|
||
while span.from_expansion() && span.ctxt() != to {
|
||
let outer_expn = self.outer_expn(span.ctxt());
|
||
debug!("walk_chain({:?}): outer_expn={:?}", span, outer_expn);
|
||
let expn_data = self.expn_data(outer_expn);
|
||
debug!("walk_chain({:?}): expn_data={:?}", span, expn_data);
|
||
span = expn_data.call_site;
|
||
}
|
||
span
|
||
}
|
||
|
||
fn adjust(&self, ctxt: &mut SyntaxContext, expn_id: ExpnId) -> Option<ExpnId> {
|
||
let mut scope = None;
|
||
while !self.is_descendant_of(expn_id, self.outer_expn(*ctxt)) {
|
||
scope = Some(self.remove_mark(ctxt).0);
|
||
}
|
||
scope
|
||
}
|
||
|
||
fn apply_mark(
|
||
&mut self,
|
||
ctxt: SyntaxContext,
|
||
expn_id: ExpnId,
|
||
transparency: Transparency,
|
||
) -> SyntaxContext {
|
||
assert_ne!(expn_id, ExpnId::root());
|
||
if transparency == Transparency::Opaque {
|
||
return self.apply_mark_internal(ctxt, expn_id, transparency);
|
||
}
|
||
|
||
let call_site_ctxt = self.expn_data(expn_id).call_site.ctxt();
|
||
let mut call_site_ctxt = if transparency == Transparency::SemiTransparent {
|
||
self.normalize_to_macros_2_0(call_site_ctxt)
|
||
} else {
|
||
self.normalize_to_macro_rules(call_site_ctxt)
|
||
};
|
||
|
||
if call_site_ctxt.is_root() {
|
||
return self.apply_mark_internal(ctxt, expn_id, transparency);
|
||
}
|
||
|
||
// Otherwise, `expn_id` is a macros 1.0 definition and the call site is in a
|
||
// macros 2.0 expansion, i.e., a macros 1.0 invocation is in a macros 2.0 definition.
|
||
//
|
||
// In this case, the tokens from the macros 1.0 definition inherit the hygiene
|
||
// at their invocation. That is, we pretend that the macros 1.0 definition
|
||
// was defined at its invocation (i.e., inside the macros 2.0 definition)
|
||
// so that the macros 2.0 definition remains hygienic.
|
||
//
|
||
// See the example at `test/ui/hygiene/legacy_interaction.rs`.
|
||
for (expn_id, transparency) in self.marks(ctxt) {
|
||
call_site_ctxt = self.apply_mark_internal(call_site_ctxt, expn_id, transparency);
|
||
}
|
||
self.apply_mark_internal(call_site_ctxt, expn_id, transparency)
|
||
}
|
||
|
||
fn apply_mark_internal(
|
||
&mut self,
|
||
ctxt: SyntaxContext,
|
||
expn_id: ExpnId,
|
||
transparency: Transparency,
|
||
) -> SyntaxContext {
|
||
let syntax_context_data = &mut self.syntax_context_data;
|
||
let mut opaque = syntax_context_data[ctxt.0 as usize].opaque;
|
||
let mut opaque_and_semitransparent =
|
||
syntax_context_data[ctxt.0 as usize].opaque_and_semitransparent;
|
||
|
||
if transparency >= Transparency::Opaque {
|
||
let parent = opaque;
|
||
opaque = *self
|
||
.syntax_context_map
|
||
.entry((parent, expn_id, transparency))
|
||
.or_insert_with(|| {
|
||
let new_opaque = SyntaxContext(syntax_context_data.len() as u32);
|
||
syntax_context_data.push(SyntaxContextData {
|
||
outer_expn: expn_id,
|
||
outer_transparency: transparency,
|
||
parent,
|
||
opaque: new_opaque,
|
||
opaque_and_semitransparent: new_opaque,
|
||
dollar_crate_name: kw::DollarCrate,
|
||
});
|
||
new_opaque
|
||
});
|
||
}
|
||
|
||
if transparency >= Transparency::SemiTransparent {
|
||
let parent = opaque_and_semitransparent;
|
||
opaque_and_semitransparent = *self
|
||
.syntax_context_map
|
||
.entry((parent, expn_id, transparency))
|
||
.or_insert_with(|| {
|
||
let new_opaque_and_semitransparent =
|
||
SyntaxContext(syntax_context_data.len() as u32);
|
||
syntax_context_data.push(SyntaxContextData {
|
||
outer_expn: expn_id,
|
||
outer_transparency: transparency,
|
||
parent,
|
||
opaque,
|
||
opaque_and_semitransparent: new_opaque_and_semitransparent,
|
||
dollar_crate_name: kw::DollarCrate,
|
||
});
|
||
new_opaque_and_semitransparent
|
||
});
|
||
}
|
||
|
||
let parent = ctxt;
|
||
*self.syntax_context_map.entry((parent, expn_id, transparency)).or_insert_with(|| {
|
||
let new_opaque_and_semitransparent_and_transparent =
|
||
SyntaxContext(syntax_context_data.len() as u32);
|
||
syntax_context_data.push(SyntaxContextData {
|
||
outer_expn: expn_id,
|
||
outer_transparency: transparency,
|
||
parent,
|
||
opaque,
|
||
opaque_and_semitransparent,
|
||
dollar_crate_name: kw::DollarCrate,
|
||
});
|
||
new_opaque_and_semitransparent_and_transparent
|
||
})
|
||
}
|
||
}
|
||
|
||
pub fn clear_syntax_context_map() {
|
||
HygieneData::with(|data| data.syntax_context_map = FxHashMap::default());
|
||
}
|
||
|
||
pub fn walk_chain(span: Span, to: SyntaxContext) -> Span {
|
||
HygieneData::with(|data| data.walk_chain(span, to))
|
||
}
|
||
|
||
pub fn update_dollar_crate_names(mut get_name: impl FnMut(SyntaxContext) -> Symbol) {
|
||
// The new contexts that need updating are at the end of the list and have `$crate` as a name.
|
||
let (len, to_update) = HygieneData::with(|data| {
|
||
(
|
||
data.syntax_context_data.len(),
|
||
data.syntax_context_data
|
||
.iter()
|
||
.rev()
|
||
.take_while(|scdata| scdata.dollar_crate_name == kw::DollarCrate)
|
||
.count(),
|
||
)
|
||
});
|
||
// The callback must be called from outside of the `HygieneData` lock,
|
||
// since it will try to acquire it too.
|
||
let range_to_update = len - to_update..len;
|
||
let names: Vec<_> =
|
||
range_to_update.clone().map(|idx| get_name(SyntaxContext::from_u32(idx as u32))).collect();
|
||
HygieneData::with(|data| {
|
||
range_to_update.zip(names).for_each(|(idx, name)| {
|
||
data.syntax_context_data[idx].dollar_crate_name = name;
|
||
})
|
||
})
|
||
}
|
||
|
||
pub fn debug_hygiene_data(verbose: bool) -> String {
|
||
HygieneData::with(|data| {
|
||
if verbose {
|
||
format!("{data:#?}")
|
||
} else {
|
||
let mut s = String::from("Expansions:");
|
||
let mut debug_expn_data = |(id, expn_data): (&ExpnId, &ExpnData)| {
|
||
s.push_str(&format!(
|
||
"\n{:?}: parent: {:?}, call_site_ctxt: {:?}, def_site_ctxt: {:?}, kind: {:?}",
|
||
id,
|
||
expn_data.parent,
|
||
expn_data.call_site.ctxt(),
|
||
expn_data.def_site.ctxt(),
|
||
expn_data.kind,
|
||
))
|
||
};
|
||
data.local_expn_data.iter_enumerated().for_each(|(id, expn_data)| {
|
||
let expn_data = expn_data.as_ref().expect("no expansion data for an expansion ID");
|
||
debug_expn_data((&id.to_expn_id(), expn_data))
|
||
});
|
||
|
||
// Sort the hash map for more reproducible output.
|
||
// Because of this, it is fine to rely on the unstable iteration order of the map.
|
||
#[allow(rustc::potential_query_instability)]
|
||
let mut foreign_expn_data: Vec<_> = data.foreign_expn_data.iter().collect();
|
||
foreign_expn_data.sort_by_key(|(id, _)| (id.krate, id.local_id));
|
||
foreign_expn_data.into_iter().for_each(debug_expn_data);
|
||
s.push_str("\n\nSyntaxContexts:");
|
||
data.syntax_context_data.iter().enumerate().for_each(|(id, ctxt)| {
|
||
s.push_str(&format!(
|
||
"\n#{}: parent: {:?}, outer_mark: ({:?}, {:?})",
|
||
id, ctxt.parent, ctxt.outer_expn, ctxt.outer_transparency,
|
||
));
|
||
});
|
||
s
|
||
}
|
||
})
|
||
}
|
||
|
||
impl SyntaxContext {
|
||
#[inline]
|
||
pub const fn root() -> Self {
|
||
SyntaxContext(0)
|
||
}
|
||
|
||
#[inline]
|
||
pub const fn is_root(self) -> bool {
|
||
self.0 == SyntaxContext::root().as_u32()
|
||
}
|
||
|
||
#[inline]
|
||
pub(crate) const fn as_u32(self) -> u32 {
|
||
self.0
|
||
}
|
||
|
||
#[inline]
|
||
pub(crate) const fn from_u32(raw: u32) -> SyntaxContext {
|
||
SyntaxContext(raw)
|
||
}
|
||
|
||
/// Extend a syntax context with a given expansion and transparency.
|
||
pub(crate) fn apply_mark(self, expn_id: ExpnId, transparency: Transparency) -> SyntaxContext {
|
||
HygieneData::with(|data| data.apply_mark(self, expn_id, transparency))
|
||
}
|
||
|
||
/// Pulls a single mark off of the syntax context. This effectively moves the
|
||
/// context up one macro definition level. That is, if we have a nested macro
|
||
/// definition as follows:
|
||
///
|
||
/// ```ignore (illustrative)
|
||
/// macro_rules! f {
|
||
/// macro_rules! g {
|
||
/// ...
|
||
/// }
|
||
/// }
|
||
/// ```
|
||
///
|
||
/// and we have a SyntaxContext that is referring to something declared by an invocation
|
||
/// of g (call it g1), calling remove_mark will result in the SyntaxContext for the
|
||
/// invocation of f that created g1.
|
||
/// Returns the mark that was removed.
|
||
pub fn remove_mark(&mut self) -> ExpnId {
|
||
HygieneData::with(|data| data.remove_mark(self).0)
|
||
}
|
||
|
||
pub fn marks(self) -> Vec<(ExpnId, Transparency)> {
|
||
HygieneData::with(|data| data.marks(self))
|
||
}
|
||
|
||
/// Adjust this context for resolution in a scope created by the given expansion.
|
||
/// For example, consider the following three resolutions of `f`:
|
||
///
|
||
/// ```rust
|
||
/// #![feature(decl_macro)]
|
||
/// mod foo { pub fn f() {} } // `f`'s `SyntaxContext` is empty.
|
||
/// m!(f);
|
||
/// macro m($f:ident) {
|
||
/// mod bar {
|
||
/// pub fn f() {} // `f`'s `SyntaxContext` has a single `ExpnId` from `m`.
|
||
/// pub fn $f() {} // `$f`'s `SyntaxContext` is empty.
|
||
/// }
|
||
/// foo::f(); // `f`'s `SyntaxContext` has a single `ExpnId` from `m`
|
||
/// //^ Since `mod foo` is outside this expansion, `adjust` removes the mark from `f`,
|
||
/// //| and it resolves to `::foo::f`.
|
||
/// bar::f(); // `f`'s `SyntaxContext` has a single `ExpnId` from `m`
|
||
/// //^ Since `mod bar` not outside this expansion, `adjust` does not change `f`,
|
||
/// //| and it resolves to `::bar::f`.
|
||
/// bar::$f(); // `f`'s `SyntaxContext` is empty.
|
||
/// //^ Since `mod bar` is not outside this expansion, `adjust` does not change `$f`,
|
||
/// //| and it resolves to `::bar::$f`.
|
||
/// }
|
||
/// ```
|
||
/// This returns the expansion whose definition scope we use to privacy check the resolution,
|
||
/// or `None` if we privacy check as usual (i.e., not w.r.t. a macro definition scope).
|
||
pub fn adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
|
||
HygieneData::with(|data| data.adjust(self, expn_id))
|
||
}
|
||
|
||
/// Like `SyntaxContext::adjust`, but also normalizes `self` to macros 2.0.
|
||
pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
|
||
HygieneData::with(|data| {
|
||
*self = data.normalize_to_macros_2_0(*self);
|
||
data.adjust(self, expn_id)
|
||
})
|
||
}
|
||
|
||
/// Adjust this context for resolution in a scope created by the given expansion
|
||
/// via a glob import with the given `SyntaxContext`.
|
||
/// For example:
|
||
///
|
||
/// ```compile_fail,E0425
|
||
/// #![feature(decl_macro)]
|
||
/// m!(f);
|
||
/// macro m($i:ident) {
|
||
/// mod foo {
|
||
/// pub fn f() {} // `f`'s `SyntaxContext` has a single `ExpnId` from `m`.
|
||
/// pub fn $i() {} // `$i`'s `SyntaxContext` is empty.
|
||
/// }
|
||
/// n!(f);
|
||
/// macro n($j:ident) {
|
||
/// use foo::*;
|
||
/// f(); // `f`'s `SyntaxContext` has a mark from `m` and a mark from `n`
|
||
/// //^ `glob_adjust` removes the mark from `n`, so this resolves to `foo::f`.
|
||
/// $i(); // `$i`'s `SyntaxContext` has a mark from `n`
|
||
/// //^ `glob_adjust` removes the mark from `n`, so this resolves to `foo::$i`.
|
||
/// $j(); // `$j`'s `SyntaxContext` has a mark from `m`
|
||
/// //^ This cannot be glob-adjusted, so this is a resolution error.
|
||
/// }
|
||
/// }
|
||
/// ```
|
||
/// This returns `None` if the context cannot be glob-adjusted.
|
||
/// Otherwise, it returns the scope to use when privacy checking (see `adjust` for details).
|
||
pub fn glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option<Option<ExpnId>> {
|
||
HygieneData::with(|data| {
|
||
let mut scope = None;
|
||
let mut glob_ctxt = data.normalize_to_macros_2_0(glob_span.ctxt());
|
||
while !data.is_descendant_of(expn_id, data.outer_expn(glob_ctxt)) {
|
||
scope = Some(data.remove_mark(&mut glob_ctxt).0);
|
||
if data.remove_mark(self).0 != scope.unwrap() {
|
||
return None;
|
||
}
|
||
}
|
||
if data.adjust(self, expn_id).is_some() {
|
||
return None;
|
||
}
|
||
Some(scope)
|
||
})
|
||
}
|
||
|
||
/// Undo `glob_adjust` if possible:
|
||
///
|
||
/// ```ignore (illustrative)
|
||
/// if let Some(privacy_checking_scope) = self.reverse_glob_adjust(expansion, glob_ctxt) {
|
||
/// assert!(self.glob_adjust(expansion, glob_ctxt) == Some(privacy_checking_scope));
|
||
/// }
|
||
/// ```
|
||
pub fn reverse_glob_adjust(
|
||
&mut self,
|
||
expn_id: ExpnId,
|
||
glob_span: Span,
|
||
) -> Option<Option<ExpnId>> {
|
||
HygieneData::with(|data| {
|
||
if data.adjust(self, expn_id).is_some() {
|
||
return None;
|
||
}
|
||
|
||
let mut glob_ctxt = data.normalize_to_macros_2_0(glob_span.ctxt());
|
||
let mut marks = Vec::new();
|
||
while !data.is_descendant_of(expn_id, data.outer_expn(glob_ctxt)) {
|
||
marks.push(data.remove_mark(&mut glob_ctxt));
|
||
}
|
||
|
||
let scope = marks.last().map(|mark| mark.0);
|
||
while let Some((expn_id, transparency)) = marks.pop() {
|
||
*self = data.apply_mark(*self, expn_id, transparency);
|
||
}
|
||
Some(scope)
|
||
})
|
||
}
|
||
|
||
pub fn hygienic_eq(self, other: SyntaxContext, expn_id: ExpnId) -> bool {
|
||
HygieneData::with(|data| {
|
||
let mut self_normalized = data.normalize_to_macros_2_0(self);
|
||
data.adjust(&mut self_normalized, expn_id);
|
||
self_normalized == data.normalize_to_macros_2_0(other)
|
||
})
|
||
}
|
||
|
||
#[inline]
|
||
pub fn normalize_to_macros_2_0(self) -> SyntaxContext {
|
||
HygieneData::with(|data| data.normalize_to_macros_2_0(self))
|
||
}
|
||
|
||
#[inline]
|
||
pub fn normalize_to_macro_rules(self) -> SyntaxContext {
|
||
HygieneData::with(|data| data.normalize_to_macro_rules(self))
|
||
}
|
||
|
||
#[inline]
|
||
pub fn outer_expn(self) -> ExpnId {
|
||
HygieneData::with(|data| data.outer_expn(self))
|
||
}
|
||
|
||
/// `ctxt.outer_expn_data()` is equivalent to but faster than
|
||
/// `ctxt.outer_expn().expn_data()`.
|
||
#[inline]
|
||
pub fn outer_expn_data(self) -> ExpnData {
|
||
HygieneData::with(|data| data.expn_data(data.outer_expn(self)).clone())
|
||
}
|
||
|
||
#[inline]
|
||
pub fn outer_mark(self) -> (ExpnId, Transparency) {
|
||
HygieneData::with(|data| data.outer_mark(self))
|
||
}
|
||
|
||
pub fn dollar_crate_name(self) -> Symbol {
|
||
HygieneData::with(|data| data.syntax_context_data[self.0 as usize].dollar_crate_name)
|
||
}
|
||
|
||
pub fn edition(self) -> Edition {
|
||
HygieneData::with(|data| data.expn_data(data.outer_expn(self)).edition)
|
||
}
|
||
}
|
||
|
||
impl fmt::Debug for SyntaxContext {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
write!(f, "#{}", self.0)
|
||
}
|
||
}
|
||
|
||
impl Span {
|
||
/// Creates a fresh expansion with given properties.
|
||
/// Expansions are normally created by macros, but in some cases expansions are created for
|
||
/// other compiler-generated code to set per-span properties like allowed unstable features.
|
||
/// The returned span belongs to the created expansion and has the new properties,
|
||
/// but its location is inherited from the current span.
|
||
pub fn fresh_expansion(self, expn_id: LocalExpnId) -> Span {
|
||
HygieneData::with(|data| {
|
||
self.with_ctxt(data.apply_mark(
|
||
self.ctxt(),
|
||
expn_id.to_expn_id(),
|
||
Transparency::Transparent,
|
||
))
|
||
})
|
||
}
|
||
|
||
/// Reuses the span but adds information like the kind of the desugaring and features that are
|
||
/// allowed inside this span.
|
||
pub fn mark_with_reason(
|
||
self,
|
||
allow_internal_unstable: Option<Lrc<[Symbol]>>,
|
||
reason: DesugaringKind,
|
||
edition: Edition,
|
||
ctx: impl HashStableContext,
|
||
) -> Span {
|
||
let expn_data = ExpnData {
|
||
allow_internal_unstable,
|
||
..ExpnData::default(ExpnKind::Desugaring(reason), self, edition, None, None)
|
||
};
|
||
let expn_id = LocalExpnId::fresh(expn_data, ctx);
|
||
self.fresh_expansion(expn_id)
|
||
}
|
||
}
|
||
|
||
/// A subset of properties from both macro definition and macro call available through global data.
|
||
/// Avoid using this if you have access to the original definition or call structures.
|
||
#[derive(Clone, Debug, Encodable, Decodable, HashStable_Generic)]
|
||
pub struct ExpnData {
|
||
// --- The part unique to each expansion.
|
||
/// The kind of this expansion - macro or compiler desugaring.
|
||
pub kind: ExpnKind,
|
||
/// The expansion that produced this expansion.
|
||
pub parent: ExpnId,
|
||
/// The location of the actual macro invocation or syntax sugar , e.g.
|
||
/// `let x = foo!();` or `if let Some(y) = x {}`
|
||
///
|
||
/// This may recursively refer to other macro invocations, e.g., if
|
||
/// `foo!()` invoked `bar!()` internally, and there was an
|
||
/// expression inside `bar!`; the call_site of the expression in
|
||
/// the expansion would point to the `bar!` invocation; that
|
||
/// call_site span would have its own ExpnData, with the call_site
|
||
/// pointing to the `foo!` invocation.
|
||
pub call_site: Span,
|
||
/// Used to force two `ExpnData`s to have different `Fingerprint`s.
|
||
/// Due to macro expansion, it's possible to end up with two `ExpnId`s
|
||
/// that have identical `ExpnData`s. This violates the contract of `HashStable`
|
||
/// - the two `ExpnId`s are not equal, but their `Fingerprint`s are equal
|
||
/// (since the numerical `ExpnId` value is not considered by the `HashStable`
|
||
/// implementation).
|
||
///
|
||
/// The `disambiguator` field is set by `update_disambiguator` when two distinct
|
||
/// `ExpnId`s would end up with the same `Fingerprint`. Since `ExpnData` includes
|
||
/// a `krate` field, this value only needs to be unique within a single crate.
|
||
disambiguator: u32,
|
||
|
||
// --- The part specific to the macro/desugaring definition.
|
||
// --- It may be reasonable to share this part between expansions with the same definition,
|
||
// --- but such sharing is known to bring some minor inconveniences without also bringing
|
||
// --- noticeable perf improvements (PR #62898).
|
||
/// The span of the macro definition (possibly dummy).
|
||
/// This span serves only informational purpose and is not used for resolution.
|
||
pub def_site: Span,
|
||
/// List of `#[unstable]`/feature-gated features that the macro is allowed to use
|
||
/// internally without forcing the whole crate to opt-in
|
||
/// to them.
|
||
pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
|
||
/// Edition of the crate in which the macro is defined.
|
||
pub edition: Edition,
|
||
/// The `DefId` of the macro being invoked,
|
||
/// if this `ExpnData` corresponds to a macro invocation
|
||
pub macro_def_id: Option<DefId>,
|
||
/// The normal module (`mod`) in which the expanded macro was defined.
|
||
pub parent_module: Option<DefId>,
|
||
/// Suppresses the `unsafe_code` lint for code produced by this macro.
|
||
pub allow_internal_unsafe: bool,
|
||
/// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
|
||
pub local_inner_macros: bool,
|
||
/// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
|
||
/// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
|
||
pub collapse_debuginfo: bool,
|
||
}
|
||
|
||
impl !PartialEq for ExpnData {}
|
||
impl !Hash for ExpnData {}
|
||
|
||
impl ExpnData {
|
||
pub fn new(
|
||
kind: ExpnKind,
|
||
parent: ExpnId,
|
||
call_site: Span,
|
||
def_site: Span,
|
||
allow_internal_unstable: Option<Lrc<[Symbol]>>,
|
||
edition: Edition,
|
||
macro_def_id: Option<DefId>,
|
||
parent_module: Option<DefId>,
|
||
allow_internal_unsafe: bool,
|
||
local_inner_macros: bool,
|
||
collapse_debuginfo: bool,
|
||
) -> ExpnData {
|
||
ExpnData {
|
||
kind,
|
||
parent,
|
||
call_site,
|
||
def_site,
|
||
allow_internal_unstable,
|
||
edition,
|
||
macro_def_id,
|
||
parent_module,
|
||
disambiguator: 0,
|
||
allow_internal_unsafe,
|
||
local_inner_macros,
|
||
collapse_debuginfo,
|
||
}
|
||
}
|
||
|
||
/// Constructs expansion data with default properties.
|
||
pub fn default(
|
||
kind: ExpnKind,
|
||
call_site: Span,
|
||
edition: Edition,
|
||
macro_def_id: Option<DefId>,
|
||
parent_module: Option<DefId>,
|
||
) -> ExpnData {
|
||
ExpnData {
|
||
kind,
|
||
parent: ExpnId::root(),
|
||
call_site,
|
||
def_site: DUMMY_SP,
|
||
allow_internal_unstable: None,
|
||
edition,
|
||
macro_def_id,
|
||
parent_module,
|
||
disambiguator: 0,
|
||
allow_internal_unsafe: false,
|
||
local_inner_macros: false,
|
||
collapse_debuginfo: false,
|
||
}
|
||
}
|
||
|
||
pub fn allow_unstable(
|
||
kind: ExpnKind,
|
||
call_site: Span,
|
||
edition: Edition,
|
||
allow_internal_unstable: Lrc<[Symbol]>,
|
||
macro_def_id: Option<DefId>,
|
||
parent_module: Option<DefId>,
|
||
) -> ExpnData {
|
||
ExpnData {
|
||
allow_internal_unstable: Some(allow_internal_unstable),
|
||
..ExpnData::default(kind, call_site, edition, macro_def_id, parent_module)
|
||
}
|
||
}
|
||
|
||
#[inline]
|
||
pub fn is_root(&self) -> bool {
|
||
matches!(self.kind, ExpnKind::Root)
|
||
}
|
||
|
||
#[inline]
|
||
fn hash_expn(&self, ctx: &mut impl HashStableContext) -> Hash64 {
|
||
let mut hasher = StableHasher::new();
|
||
self.hash_stable(ctx, &mut hasher);
|
||
hasher.finish()
|
||
}
|
||
}
|
||
|
||
/// Expansion kind.
|
||
#[derive(Clone, Debug, PartialEq, Encodable, Decodable, HashStable_Generic)]
|
||
pub enum ExpnKind {
|
||
/// No expansion, aka root expansion. Only `ExpnId::root()` has this kind.
|
||
Root,
|
||
/// Expansion produced by a macro.
|
||
Macro(MacroKind, Symbol),
|
||
/// Transform done by the compiler on the AST.
|
||
AstPass(AstPass),
|
||
/// Desugaring done by the compiler during HIR lowering.
|
||
Desugaring(DesugaringKind),
|
||
}
|
||
|
||
impl ExpnKind {
|
||
pub fn descr(&self) -> String {
|
||
match *self {
|
||
ExpnKind::Root => kw::PathRoot.to_string(),
|
||
ExpnKind::Macro(macro_kind, name) => match macro_kind {
|
||
MacroKind::Bang => format!("{name}!"),
|
||
MacroKind::Attr => format!("#[{name}]"),
|
||
MacroKind::Derive => format!("#[derive({name})]"),
|
||
},
|
||
ExpnKind::AstPass(kind) => kind.descr().to_string(),
|
||
ExpnKind::Desugaring(kind) => format!("desugaring of {}", kind.descr()),
|
||
}
|
||
}
|
||
}
|
||
|
||
/// The kind of macro invocation or definition.
|
||
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
|
||
#[derive(HashStable_Generic)]
|
||
pub enum MacroKind {
|
||
/// A bang macro `foo!()`.
|
||
Bang,
|
||
/// An attribute macro `#[foo]`.
|
||
Attr,
|
||
/// A derive macro `#[derive(Foo)]`
|
||
Derive,
|
||
}
|
||
|
||
impl MacroKind {
|
||
pub fn descr(self) -> &'static str {
|
||
match self {
|
||
MacroKind::Bang => "macro",
|
||
MacroKind::Attr => "attribute macro",
|
||
MacroKind::Derive => "derive macro",
|
||
}
|
||
}
|
||
|
||
pub fn descr_expected(self) -> &'static str {
|
||
match self {
|
||
MacroKind::Attr => "attribute",
|
||
_ => self.descr(),
|
||
}
|
||
}
|
||
|
||
pub fn article(self) -> &'static str {
|
||
match self {
|
||
MacroKind::Attr => "an",
|
||
_ => "a",
|
||
}
|
||
}
|
||
}
|
||
|
||
/// The kind of AST transform.
|
||
#[derive(Clone, Copy, Debug, PartialEq, Encodable, Decodable, HashStable_Generic)]
|
||
pub enum AstPass {
|
||
StdImports,
|
||
TestHarness,
|
||
ProcMacroHarness,
|
||
}
|
||
|
||
impl AstPass {
|
||
pub fn descr(self) -> &'static str {
|
||
match self {
|
||
AstPass::StdImports => "standard library imports",
|
||
AstPass::TestHarness => "test harness",
|
||
AstPass::ProcMacroHarness => "proc macro harness",
|
||
}
|
||
}
|
||
}
|
||
|
||
/// The kind of compiler desugaring.
|
||
#[derive(Clone, Copy, PartialEq, Debug, Encodable, Decodable, HashStable_Generic)]
|
||
pub enum DesugaringKind {
|
||
/// We desugar `if c { i } else { e }` to `match $ExprKind::Use(c) { true => i, _ => e }`.
|
||
/// However, we do not want to blame `c` for unreachability but rather say that `i`
|
||
/// is unreachable. This desugaring kind allows us to avoid blaming `c`.
|
||
/// This also applies to `while` loops.
|
||
CondTemporary,
|
||
QuestionMark,
|
||
TryBlock,
|
||
YeetExpr,
|
||
/// Desugaring of an `impl Trait` in return type position
|
||
/// to an `type Foo = impl Trait;` and replacing the
|
||
/// `impl Trait` with `Foo`.
|
||
OpaqueTy,
|
||
Async,
|
||
Await,
|
||
ForLoop,
|
||
WhileLoop,
|
||
}
|
||
|
||
impl DesugaringKind {
|
||
/// The description wording should combine well with "desugaring of {}".
|
||
pub fn descr(self) -> &'static str {
|
||
match self {
|
||
DesugaringKind::CondTemporary => "`if` or `while` condition",
|
||
DesugaringKind::Async => "`async` block or function",
|
||
DesugaringKind::Await => "`await` expression",
|
||
DesugaringKind::QuestionMark => "operator `?`",
|
||
DesugaringKind::TryBlock => "`try` block",
|
||
DesugaringKind::YeetExpr => "`do yeet` expression",
|
||
DesugaringKind::OpaqueTy => "`impl Trait`",
|
||
DesugaringKind::ForLoop => "`for` loop",
|
||
DesugaringKind::WhileLoop => "`while` loop",
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Default)]
|
||
pub struct HygieneEncodeContext {
|
||
/// All `SyntaxContexts` for which we have written `SyntaxContextData` into crate metadata.
|
||
/// This is `None` after we finish encoding `SyntaxContexts`, to ensure
|
||
/// that we don't accidentally try to encode any more `SyntaxContexts`
|
||
serialized_ctxts: Lock<FxHashSet<SyntaxContext>>,
|
||
/// The `SyntaxContexts` that we have serialized (e.g. as a result of encoding `Spans`)
|
||
/// in the most recent 'round' of serializing. Serializing `SyntaxContextData`
|
||
/// may cause us to serialize more `SyntaxContext`s, so serialize in a loop
|
||
/// until we reach a fixed point.
|
||
latest_ctxts: Lock<FxHashSet<SyntaxContext>>,
|
||
|
||
serialized_expns: Lock<FxHashSet<ExpnId>>,
|
||
|
||
latest_expns: Lock<FxHashSet<ExpnId>>,
|
||
}
|
||
|
||
impl HygieneEncodeContext {
|
||
/// Record the fact that we need to serialize the corresponding `ExpnData`.
|
||
pub fn schedule_expn_data_for_encoding(&self, expn: ExpnId) {
|
||
if !self.serialized_expns.lock().contains(&expn) {
|
||
self.latest_expns.lock().insert(expn);
|
||
}
|
||
}
|
||
|
||
pub fn encode<T>(
|
||
&self,
|
||
encoder: &mut T,
|
||
mut encode_ctxt: impl FnMut(&mut T, u32, &SyntaxContextData),
|
||
mut encode_expn: impl FnMut(&mut T, ExpnId, &ExpnData, ExpnHash),
|
||
) {
|
||
// When we serialize a `SyntaxContextData`, we may end up serializing
|
||
// a `SyntaxContext` that we haven't seen before
|
||
while !self.latest_ctxts.lock().is_empty() || !self.latest_expns.lock().is_empty() {
|
||
debug!(
|
||
"encode_hygiene: Serializing a round of {:?} SyntaxContextData: {:?}",
|
||
self.latest_ctxts.lock().len(),
|
||
self.latest_ctxts
|
||
);
|
||
|
||
// Consume the current round of SyntaxContexts.
|
||
// Drop the lock() temporary early
|
||
let latest_ctxts = { std::mem::take(&mut *self.latest_ctxts.lock()) };
|
||
|
||
// It's fine to iterate over a HashMap, because the serialization
|
||
// of the table that we insert data into doesn't depend on insertion
|
||
// order
|
||
#[allow(rustc::potential_query_instability)]
|
||
for_all_ctxts_in(latest_ctxts.into_iter(), |index, ctxt, data| {
|
||
if self.serialized_ctxts.lock().insert(ctxt) {
|
||
encode_ctxt(encoder, index, data);
|
||
}
|
||
});
|
||
|
||
let latest_expns = { std::mem::take(&mut *self.latest_expns.lock()) };
|
||
|
||
// Same as above, this is fine as we are inserting into a order-independent hashset
|
||
#[allow(rustc::potential_query_instability)]
|
||
for_all_expns_in(latest_expns.into_iter(), |expn, data, hash| {
|
||
if self.serialized_expns.lock().insert(expn) {
|
||
encode_expn(encoder, expn, data, hash);
|
||
}
|
||
});
|
||
}
|
||
debug!("encode_hygiene: Done serializing SyntaxContextData");
|
||
}
|
||
}
|
||
|
||
#[derive(Default)]
|
||
/// Additional information used to assist in decoding hygiene data
|
||
struct HygieneDecodeContextInner {
|
||
// Maps serialized `SyntaxContext` ids to a `SyntaxContext` in the current
|
||
// global `HygieneData`. When we deserialize a `SyntaxContext`, we need to create
|
||
// a new id in the global `HygieneData`. This map tracks the ID we end up picking,
|
||
// so that multiple occurrences of the same serialized id are decoded to the same
|
||
// `SyntaxContext`. This only stores `SyntaxContext`s which are completly decoded.
|
||
remapped_ctxts: Vec<Option<SyntaxContext>>,
|
||
|
||
/// Maps serialized `SyntaxContext` ids that are currently being decoded to a `SyntaxContext`.
|
||
decoding: FxHashMap<u32, SyntaxContext>,
|
||
}
|
||
|
||
#[derive(Default)]
|
||
/// Additional information used to assist in decoding hygiene data
|
||
pub struct HygieneDecodeContext {
|
||
inner: Lock<HygieneDecodeContextInner>,
|
||
|
||
/// A set of serialized `SyntaxContext` ids that are currently being decoded on each thread.
|
||
local_in_progress: WorkerLocal<RefCell<FxHashMap<u32, ()>>>,
|
||
}
|
||
|
||
/// Register an expansion which has been decoded from the on-disk-cache for the local crate.
|
||
pub fn register_local_expn_id(data: ExpnData, hash: ExpnHash) -> ExpnId {
|
||
HygieneData::with(|hygiene_data| {
|
||
let expn_id = hygiene_data.local_expn_data.next_index();
|
||
hygiene_data.local_expn_data.push(Some(data));
|
||
let _eid = hygiene_data.local_expn_hashes.push(hash);
|
||
debug_assert_eq!(expn_id, _eid);
|
||
|
||
let expn_id = expn_id.to_expn_id();
|
||
|
||
let _old_id = hygiene_data.expn_hash_to_expn_id.insert(hash, expn_id);
|
||
debug_assert!(_old_id.is_none());
|
||
expn_id
|
||
})
|
||
}
|
||
|
||
/// Register an expansion which has been decoded from the metadata of a foreign crate.
|
||
pub fn register_expn_id(
|
||
krate: CrateNum,
|
||
local_id: ExpnIndex,
|
||
data: ExpnData,
|
||
hash: ExpnHash,
|
||
) -> ExpnId {
|
||
debug_assert!(data.parent == ExpnId::root() || krate == data.parent.krate);
|
||
let expn_id = ExpnId { krate, local_id };
|
||
HygieneData::with(|hygiene_data| {
|
||
let _old_data = hygiene_data.foreign_expn_data.insert(expn_id, data);
|
||
debug_assert!(_old_data.is_none() || cfg!(parallel_compiler));
|
||
let _old_hash = hygiene_data.foreign_expn_hashes.insert(expn_id, hash);
|
||
debug_assert!(_old_hash.is_none() || _old_hash == Some(hash));
|
||
let _old_id = hygiene_data.expn_hash_to_expn_id.insert(hash, expn_id);
|
||
debug_assert!(_old_id.is_none() || _old_id == Some(expn_id));
|
||
});
|
||
expn_id
|
||
}
|
||
|
||
/// Decode an expansion from the metadata of a foreign crate.
|
||
pub fn decode_expn_id(
|
||
krate: CrateNum,
|
||
index: u32,
|
||
decode_data: impl FnOnce(ExpnId) -> (ExpnData, ExpnHash),
|
||
) -> ExpnId {
|
||
if index == 0 {
|
||
trace!("decode_expn_id: deserialized root");
|
||
return ExpnId::root();
|
||
}
|
||
|
||
let index = ExpnIndex::from_u32(index);
|
||
|
||
// This function is used to decode metadata, so it cannot decode information about LOCAL_CRATE.
|
||
debug_assert_ne!(krate, LOCAL_CRATE);
|
||
let expn_id = ExpnId { krate, local_id: index };
|
||
|
||
// Fast path if the expansion has already been decoded.
|
||
if HygieneData::with(|hygiene_data| hygiene_data.foreign_expn_data.contains_key(&expn_id)) {
|
||
return expn_id;
|
||
}
|
||
|
||
// Don't decode the data inside `HygieneData::with`, since we need to recursively decode
|
||
// other ExpnIds
|
||
let (expn_data, hash) = decode_data(expn_id);
|
||
|
||
register_expn_id(krate, index, expn_data, hash)
|
||
}
|
||
|
||
// Decodes `SyntaxContext`, using the provided `HygieneDecodeContext`
|
||
// to track which `SyntaxContext`s we have already decoded.
|
||
// The provided closure will be invoked to deserialize a `SyntaxContextData`
|
||
// if we haven't already seen the id of the `SyntaxContext` we are deserializing.
|
||
pub fn decode_syntax_context<D: Decoder, F: FnOnce(&mut D, u32) -> SyntaxContextData>(
|
||
d: &mut D,
|
||
context: &HygieneDecodeContext,
|
||
decode_data: F,
|
||
) -> SyntaxContext {
|
||
let raw_id: u32 = Decodable::decode(d);
|
||
if raw_id == 0 {
|
||
trace!("decode_syntax_context: deserialized root");
|
||
// The root is special
|
||
return SyntaxContext::root();
|
||
}
|
||
|
||
let ctxt = {
|
||
let mut inner = context.inner.lock();
|
||
|
||
if let Some(ctxt) = inner.remapped_ctxts.get(raw_id as usize).copied().flatten() {
|
||
// This has already beeen decoded.
|
||
return ctxt;
|
||
}
|
||
|
||
match inner.decoding.entry(raw_id) {
|
||
Entry::Occupied(ctxt_entry) => {
|
||
match context.local_in_progress.borrow_mut().entry(raw_id) {
|
||
Entry::Occupied(..) => {
|
||
// We're decoding this already on the current thread. Return here
|
||
// and let the function higher up the stack finish decoding to handle
|
||
// recursive cases.
|
||
return *ctxt_entry.get();
|
||
}
|
||
Entry::Vacant(entry) => {
|
||
entry.insert(());
|
||
|
||
// Some other thread is current decoding this. Race with it.
|
||
*ctxt_entry.get()
|
||
}
|
||
}
|
||
}
|
||
Entry::Vacant(entry) => {
|
||
// We are the first thread to start decoding. Mark the current thread as being progress.
|
||
context.local_in_progress.borrow_mut().insert(raw_id, ());
|
||
|
||
// Allocate and store SyntaxContext id *before* calling the decoder function,
|
||
// as the SyntaxContextData may reference itself.
|
||
let new_ctxt = HygieneData::with(|hygiene_data| {
|
||
let new_ctxt = SyntaxContext(hygiene_data.syntax_context_data.len() as u32);
|
||
// Push a dummy SyntaxContextData to ensure that nobody else can get the
|
||
// same ID as us. This will be overwritten after call `decode_Data`
|
||
hygiene_data.syntax_context_data.push(SyntaxContextData {
|
||
outer_expn: ExpnId::root(),
|
||
outer_transparency: Transparency::Transparent,
|
||
parent: SyntaxContext::root(),
|
||
opaque: SyntaxContext::root(),
|
||
opaque_and_semitransparent: SyntaxContext::root(),
|
||
dollar_crate_name: kw::Empty,
|
||
});
|
||
new_ctxt
|
||
});
|
||
entry.insert(new_ctxt);
|
||
new_ctxt
|
||
}
|
||
}
|
||
};
|
||
|
||
// Don't try to decode data while holding the lock, since we need to
|
||
// be able to recursively decode a SyntaxContext
|
||
let mut ctxt_data = decode_data(d, raw_id);
|
||
// Reset `dollar_crate_name` so that it will be updated by `update_dollar_crate_names`
|
||
// We don't care what the encoding crate set this to - we want to resolve it
|
||
// from the perspective of the current compilation session
|
||
ctxt_data.dollar_crate_name = kw::DollarCrate;
|
||
|
||
// Overwrite the dummy data with our decoded SyntaxContextData
|
||
HygieneData::with(|hygiene_data| {
|
||
let dummy = std::mem::replace(
|
||
&mut hygiene_data.syntax_context_data[ctxt.as_u32() as usize],
|
||
ctxt_data,
|
||
);
|
||
if cfg!(not(parallel_compiler)) {
|
||
// Make sure nothing weird happened while `decode_data` was running.
|
||
// We used `kw::Empty` for the dummy value and we expect nothing to be
|
||
// modifying the dummy entry.
|
||
// This does not hold for the parallel compiler as another thread may
|
||
// have inserted the fully decoded data.
|
||
assert_eq!(dummy.dollar_crate_name, kw::Empty);
|
||
}
|
||
});
|
||
|
||
// Mark the context as completed
|
||
|
||
context.local_in_progress.borrow_mut().remove(&raw_id);
|
||
|
||
let mut inner = context.inner.lock();
|
||
let new_len = raw_id as usize + 1;
|
||
if inner.remapped_ctxts.len() < new_len {
|
||
inner.remapped_ctxts.resize(new_len, None);
|
||
}
|
||
inner.remapped_ctxts[raw_id as usize] = Some(ctxt);
|
||
inner.decoding.remove(&raw_id);
|
||
|
||
ctxt
|
||
}
|
||
|
||
fn for_all_ctxts_in<F: FnMut(u32, SyntaxContext, &SyntaxContextData)>(
|
||
ctxts: impl Iterator<Item = SyntaxContext>,
|
||
mut f: F,
|
||
) {
|
||
let all_data: Vec<_> = HygieneData::with(|data| {
|
||
ctxts.map(|ctxt| (ctxt, data.syntax_context_data[ctxt.0 as usize].clone())).collect()
|
||
});
|
||
for (ctxt, data) in all_data.into_iter() {
|
||
f(ctxt.0, ctxt, &data);
|
||
}
|
||
}
|
||
|
||
fn for_all_expns_in(
|
||
expns: impl Iterator<Item = ExpnId>,
|
||
mut f: impl FnMut(ExpnId, &ExpnData, ExpnHash),
|
||
) {
|
||
let all_data: Vec<_> = HygieneData::with(|data| {
|
||
expns.map(|expn| (expn, data.expn_data(expn).clone(), data.expn_hash(expn))).collect()
|
||
});
|
||
for (expn, data, hash) in all_data.into_iter() {
|
||
f(expn, &data, hash);
|
||
}
|
||
}
|
||
|
||
impl<E: Encoder> Encodable<E> for LocalExpnId {
|
||
fn encode(&self, e: &mut E) {
|
||
self.to_expn_id().encode(e);
|
||
}
|
||
}
|
||
|
||
impl<E: Encoder> Encodable<E> for ExpnId {
|
||
default fn encode(&self, _: &mut E) {
|
||
panic!("cannot encode `ExpnId` with `{}`", std::any::type_name::<E>());
|
||
}
|
||
}
|
||
|
||
impl<D: Decoder> Decodable<D> for LocalExpnId {
|
||
fn decode(d: &mut D) -> Self {
|
||
ExpnId::expect_local(ExpnId::decode(d))
|
||
}
|
||
}
|
||
|
||
impl<D: Decoder> Decodable<D> for ExpnId {
|
||
default fn decode(_: &mut D) -> Self {
|
||
panic!("cannot decode `ExpnId` with `{}`", std::any::type_name::<D>());
|
||
}
|
||
}
|
||
|
||
pub fn raw_encode_syntax_context<E: Encoder>(
|
||
ctxt: SyntaxContext,
|
||
context: &HygieneEncodeContext,
|
||
e: &mut E,
|
||
) {
|
||
if !context.serialized_ctxts.lock().contains(&ctxt) {
|
||
context.latest_ctxts.lock().insert(ctxt);
|
||
}
|
||
ctxt.0.encode(e);
|
||
}
|
||
|
||
impl<E: Encoder> Encodable<E> for SyntaxContext {
|
||
default fn encode(&self, _: &mut E) {
|
||
panic!("cannot encode `SyntaxContext` with `{}`", std::any::type_name::<E>());
|
||
}
|
||
}
|
||
|
||
impl<D: Decoder> Decodable<D> for SyntaxContext {
|
||
default fn decode(_: &mut D) -> Self {
|
||
panic!("cannot decode `SyntaxContext` with `{}`", std::any::type_name::<D>());
|
||
}
|
||
}
|
||
|
||
/// Updates the `disambiguator` field of the corresponding `ExpnData`
|
||
/// such that the `Fingerprint` of the `ExpnData` does not collide with
|
||
/// any other `ExpnIds`.
|
||
///
|
||
/// This method is called only when an `ExpnData` is first associated
|
||
/// with an `ExpnId` (when the `ExpnId` is initially constructed, or via
|
||
/// `set_expn_data`). It is *not* called for foreign `ExpnId`s deserialized
|
||
/// from another crate's metadata - since `ExpnHash` includes the stable crate id,
|
||
/// collisions are only possible between `ExpnId`s within the same crate.
|
||
fn update_disambiguator(expn_data: &mut ExpnData, mut ctx: impl HashStableContext) -> ExpnHash {
|
||
// This disambiguator should not have been set yet.
|
||
assert_eq!(expn_data.disambiguator, 0, "Already set disambiguator for ExpnData: {expn_data:?}");
|
||
assert_default_hashing_controls(&ctx, "ExpnData (disambiguator)");
|
||
let mut expn_hash = expn_data.hash_expn(&mut ctx);
|
||
|
||
let disambiguator = HygieneData::with(|data| {
|
||
// If this is the first ExpnData with a given hash, then keep our
|
||
// disambiguator at 0 (the default u32 value)
|
||
let disambig = data.expn_data_disambiguators.entry(expn_hash).or_default();
|
||
let disambiguator = *disambig;
|
||
*disambig += 1;
|
||
disambiguator
|
||
});
|
||
|
||
if disambiguator != 0 {
|
||
debug!("Set disambiguator for expn_data={:?} expn_hash={:?}", expn_data, expn_hash);
|
||
|
||
expn_data.disambiguator = disambiguator;
|
||
expn_hash = expn_data.hash_expn(&mut ctx);
|
||
|
||
// Verify that the new disambiguator makes the hash unique
|
||
#[cfg(debug_assertions)]
|
||
HygieneData::with(|data| {
|
||
assert_eq!(
|
||
data.expn_data_disambiguators.get(&expn_hash),
|
||
None,
|
||
"Hash collision after disambiguator update!",
|
||
);
|
||
});
|
||
}
|
||
|
||
ExpnHash::new(ctx.def_path_hash(LOCAL_CRATE.as_def_id()).stable_crate_id(), expn_hash)
|
||
}
|
||
|
||
impl<CTX: HashStableContext> HashStable<CTX> for SyntaxContext {
|
||
fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
|
||
const TAG_EXPANSION: u8 = 0;
|
||
const TAG_NO_EXPANSION: u8 = 1;
|
||
|
||
if self.is_root() {
|
||
TAG_NO_EXPANSION.hash_stable(ctx, hasher);
|
||
} else {
|
||
TAG_EXPANSION.hash_stable(ctx, hasher);
|
||
let (expn_id, transparency) = self.outer_mark();
|
||
expn_id.hash_stable(ctx, hasher);
|
||
transparency.hash_stable(ctx, hasher);
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<CTX: HashStableContext> HashStable<CTX> for ExpnId {
|
||
fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
|
||
assert_default_hashing_controls(ctx, "ExpnId");
|
||
let hash = if *self == ExpnId::root() {
|
||
// Avoid fetching TLS storage for a trivial often-used value.
|
||
Fingerprint::ZERO
|
||
} else {
|
||
self.expn_hash().0
|
||
};
|
||
|
||
hash.hash_stable(ctx, hasher);
|
||
}
|
||
}
|