| //! Machinery for hygienic macros. |
| //! |
| //! Inspired by Matthew Flatt et al., “Macros That Work Together: Compile-Time Bindings, Partial |
| //! Expansion, and Definition Contexts,” *Journal of Functional Programming* 22, no. 2 |
| //! (March 1, 2012): 181–216, <https://doi.org/10.1017/S0956796812000093>. |
| |
| // Hygiene data is stored in a global variable and accessed via TLS, which |
| // means that accesses are somewhat expensive. (`HygieneData::with` |
| // encapsulates a single access.) Therefore, on hot code paths it is worth |
| // ensuring that multiple HygieneData accesses are combined into a single |
| // `HygieneData::with`. |
| // |
| // This explains why `HygieneData`, `SyntaxContext` and `ExpnId` have interfaces |
| // with a certain amount of redundancy in them. For example, |
| // `SyntaxContext::outer_expn_data` combines `SyntaxContext::outer` and |
| // `ExpnId::expn_data` so that two `HygieneData` accesses can be performed within |
| // a single `HygieneData::with` call. |
| // |
| // It also explains why many functions appear in `HygieneData` and again in |
| // `SyntaxContext` or `ExpnId`. For example, `HygieneData::outer` and |
| // `SyntaxContext::outer` do the same thing, but the former is for use within a |
| // `HygieneData::with` call while the latter is for use outside such a call. |
| // When modifying this file it is important to understand this distinction, |
| // because getting it wrong can lead to nested `HygieneData::with` calls that |
| // trigger runtime aborts. (Fortunately these are obvious and easy to fix.) |
| |
| use std::hash::Hash; |
| use std::sync::Arc; |
| use std::{fmt, iter, mem}; |
| |
| use rustc_data_structures::fingerprint::Fingerprint; |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
| use rustc_data_structures::stable_hasher::{HashStable, HashingControls, StableHasher}; |
| use rustc_data_structures::sync::Lock; |
| use rustc_data_structures::unhash::UnhashMap; |
| use rustc_hashes::Hash64; |
| use rustc_index::IndexVec; |
| use rustc_macros::{Decodable, Encodable, HashStable_Generic}; |
| use rustc_serialize::{Decodable, Decoder, Encodable, Encoder}; |
| use tracing::{debug, trace}; |
| |
| use crate::def_id::{CRATE_DEF_ID, CrateNum, DefId, LOCAL_CRATE, StableCrateId}; |
| use crate::edition::Edition; |
| use crate::source_map::SourceMap; |
| use crate::symbol::{Symbol, kw, sym}; |
| use crate::{DUMMY_SP, HashStableContext, Span, SpanDecoder, SpanEncoder, with_session_globals}; |
| |
| /// A `SyntaxContext` represents a chain of pairs `(ExpnId, Transparency)` named "marks". |
| #[derive(Clone, Copy, PartialEq, Eq, Hash)] |
| pub struct SyntaxContext(u32); |
| |
| // To ensure correctness of incremental compilation, |
| // `SyntaxContext` must not implement `Ord` or `PartialOrd`. |
| // See https://github.com/rust-lang/rust/issues/90317. |
| impl !Ord for SyntaxContext {} |
| impl !PartialOrd for SyntaxContext {} |
| |
| /// If this part of two syntax contexts is equal, then the whole syntax contexts should be equal. |
| /// The other fields are only for caching. |
| pub type SyntaxContextKey = (SyntaxContext, ExpnId, Transparency); |
| |
| #[derive(Clone, Copy, Debug)] |
| struct SyntaxContextData { |
| outer_expn: ExpnId, |
| outer_transparency: Transparency, |
| parent: SyntaxContext, |
| /// This context, but with all transparent and semi-opaque expansions filtered away. |
| opaque: SyntaxContext, |
| /// This context, but with all transparent expansions filtered away. |
| opaque_and_semiopaque: SyntaxContext, |
| /// Name of the crate to which `$crate` with this context would resolve. |
| dollar_crate_name: Symbol, |
| } |
| |
| impl SyntaxContextData { |
| fn root() -> SyntaxContextData { |
| SyntaxContextData { |
| outer_expn: ExpnId::root(), |
| outer_transparency: Transparency::Opaque, |
| parent: SyntaxContext::root(), |
| opaque: SyntaxContext::root(), |
| opaque_and_semiopaque: SyntaxContext::root(), |
| dollar_crate_name: kw::DollarCrate, |
| } |
| } |
| |
| fn key(&self) -> SyntaxContextKey { |
| (self.parent, self.outer_expn, self.outer_transparency) |
| } |
| } |
| |
| rustc_index::newtype_index! { |
| /// A unique ID associated with a macro invocation and expansion. |
| #[orderable] |
| pub struct ExpnIndex {} |
| } |
| |
| /// A unique ID associated with a macro invocation and expansion. |
| #[derive(Clone, Copy, PartialEq, Eq, Hash)] |
| pub struct ExpnId { |
| pub krate: CrateNum, |
| pub local_id: ExpnIndex, |
| } |
| |
| impl fmt::Debug for ExpnId { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| // Generate crate_::{{expn_}}. |
| write!(f, "{:?}::{{{{expn{}}}}}", self.krate, self.local_id.as_u32()) |
| } |
| } |
| |
| rustc_index::newtype_index! { |
| /// A unique ID associated with a macro invocation and expansion. |
| #[debug_format = "expn{}"] |
| pub struct LocalExpnId {} |
| } |
| |
| // To ensure correctness of incremental compilation, |
| // `LocalExpnId` must not implement `Ord` or `PartialOrd`. |
| // See https://github.com/rust-lang/rust/issues/90317. |
| impl !Ord for LocalExpnId {} |
| impl !PartialOrd for LocalExpnId {} |
| |
| /// Assert that the provided `HashStableContext` is configured with the 'default' |
| /// `HashingControls`. We should always have bailed out before getting to here |
| /// with a non-default mode. With this check in place, we can avoid the need |
| /// to maintain separate versions of `ExpnData` hashes for each permutation |
| /// of `HashingControls` settings. |
| fn assert_default_hashing_controls(ctx: &impl HashStableContext, msg: &str) { |
| match ctx.hashing_controls() { |
| // Note that we require that `hash_spans` be set according to the global |
| // `-Z incremental-ignore-spans` option. Normally, this option is disabled, |
| // which will cause us to require that this method always be called with `Span` hashing |
| // enabled. |
| // |
| // Span hashing can also be disabled without `-Z incremental-ignore-spans`. |
| // This is the case for instance when building a hash for name mangling. |
| // Such configuration must not be used for metadata. |
| HashingControls { hash_spans } |
| if hash_spans != ctx.unstable_opts_incremental_ignore_spans() => {} |
| other => panic!("Attempted hashing of {msg} with non-default HashingControls: {other:?}"), |
| } |
| } |
| |
| /// A unique hash value associated to an expansion. |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, Encodable, Decodable, HashStable_Generic)] |
| pub struct ExpnHash(Fingerprint); |
| |
| impl ExpnHash { |
| /// Returns the [StableCrateId] identifying the crate this [ExpnHash] |
| /// originates from. |
| #[inline] |
| pub fn stable_crate_id(self) -> StableCrateId { |
| StableCrateId(self.0.split().0) |
| } |
| |
| /// Returns the crate-local part of the [ExpnHash]. |
| /// |
| /// Used for assertions. |
| #[inline] |
| pub fn local_hash(self) -> Hash64 { |
| self.0.split().1 |
| } |
| |
| #[inline] |
| pub fn is_root(self) -> bool { |
| self.0 == Fingerprint::ZERO |
| } |
| |
| /// Builds a new [ExpnHash] with the given [StableCrateId] and |
| /// `local_hash`, where `local_hash` must be unique within its crate. |
| fn new(stable_crate_id: StableCrateId, local_hash: Hash64) -> ExpnHash { |
| ExpnHash(Fingerprint::new(stable_crate_id.0, local_hash)) |
| } |
| } |
| |
| /// A property of a macro expansion that determines how identifiers |
| /// produced by that expansion are resolved. |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Hash, Debug, Encodable, Decodable)] |
| #[derive(HashStable_Generic)] |
| pub enum Transparency { |
| /// Identifier produced by a transparent expansion is always resolved at call-site. |
| /// Call-site spans in procedural macros, hygiene opt-out in `macro` should use this. |
| Transparent, |
| /// Identifier produced by a semi-opaque expansion may be resolved |
| /// either at call-site or at definition-site. |
| /// If it's a local variable, label or `$crate` then it's resolved at def-site. |
| /// Otherwise it's resolved at call-site. |
| /// `macro_rules` macros behave like this, built-in macros currently behave like this too, |
| /// but that's an implementation detail. |
| SemiOpaque, |
| /// Identifier produced by an opaque expansion is always resolved at definition-site. |
| /// Def-site spans in procedural macros, identifiers from `macro` by default use this. |
| Opaque, |
| } |
| |
| impl Transparency { |
| pub fn fallback(macro_rules: bool) -> Self { |
| if macro_rules { Transparency::SemiOpaque } else { Transparency::Opaque } |
| } |
| } |
| |
| impl LocalExpnId { |
| /// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST. |
| pub const ROOT: LocalExpnId = LocalExpnId::ZERO; |
| |
| #[inline] |
| fn from_raw(idx: ExpnIndex) -> LocalExpnId { |
| LocalExpnId::from_u32(idx.as_u32()) |
| } |
| |
| #[inline] |
| pub fn as_raw(self) -> ExpnIndex { |
| ExpnIndex::from_u32(self.as_u32()) |
| } |
| |
| pub fn fresh_empty() -> LocalExpnId { |
| HygieneData::with(|data| { |
| let expn_id = data.local_expn_data.push(None); |
| let _eid = data.local_expn_hashes.push(ExpnHash(Fingerprint::ZERO)); |
| debug_assert_eq!(expn_id, _eid); |
| expn_id |
| }) |
| } |
| |
| pub fn fresh(mut expn_data: ExpnData, ctx: impl HashStableContext) -> LocalExpnId { |
| debug_assert_eq!(expn_data.parent.krate, LOCAL_CRATE); |
| let expn_hash = update_disambiguator(&mut expn_data, ctx); |
| HygieneData::with(|data| { |
| let expn_id = data.local_expn_data.push(Some(expn_data)); |
| let _eid = data.local_expn_hashes.push(expn_hash); |
| debug_assert_eq!(expn_id, _eid); |
| let _old_id = data.expn_hash_to_expn_id.insert(expn_hash, expn_id.to_expn_id()); |
| debug_assert!(_old_id.is_none()); |
| expn_id |
| }) |
| } |
| |
| #[inline] |
| pub fn expn_data(self) -> ExpnData { |
| HygieneData::with(|data| data.local_expn_data(self).clone()) |
| } |
| |
| #[inline] |
| pub fn to_expn_id(self) -> ExpnId { |
| ExpnId { krate: LOCAL_CRATE, local_id: self.as_raw() } |
| } |
| |
| #[inline] |
| pub fn set_expn_data(self, mut expn_data: ExpnData, ctx: impl HashStableContext) { |
| debug_assert_eq!(expn_data.parent.krate, LOCAL_CRATE); |
| let expn_hash = update_disambiguator(&mut expn_data, ctx); |
| HygieneData::with(|data| { |
| let old_expn_data = &mut data.local_expn_data[self]; |
| assert!(old_expn_data.is_none(), "expansion data is reset for an expansion ID"); |
| *old_expn_data = Some(expn_data); |
| debug_assert_eq!(data.local_expn_hashes[self].0, Fingerprint::ZERO); |
| data.local_expn_hashes[self] = expn_hash; |
| let _old_id = data.expn_hash_to_expn_id.insert(expn_hash, self.to_expn_id()); |
| debug_assert!(_old_id.is_none()); |
| }); |
| } |
| |
| #[inline] |
| pub fn is_descendant_of(self, ancestor: LocalExpnId) -> bool { |
| self.to_expn_id().is_descendant_of(ancestor.to_expn_id()) |
| } |
| |
| /// Returns span for the macro which originally caused this expansion to happen. |
| /// |
| /// Stops backtracing at include! boundary. |
| #[inline] |
| pub fn expansion_cause(self) -> Option<Span> { |
| self.to_expn_id().expansion_cause() |
| } |
| } |
| |
| impl ExpnId { |
| /// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST. |
| /// Invariant: we do not create any ExpnId with local_id == 0 and krate != 0. |
| pub const fn root() -> ExpnId { |
| ExpnId { krate: LOCAL_CRATE, local_id: ExpnIndex::ZERO } |
| } |
| |
| #[inline] |
| pub fn expn_hash(self) -> ExpnHash { |
| HygieneData::with(|data| data.expn_hash(self)) |
| } |
| |
| #[inline] |
| pub fn from_hash(hash: ExpnHash) -> Option<ExpnId> { |
| HygieneData::with(|data| data.expn_hash_to_expn_id.get(&hash).copied()) |
| } |
| |
| #[inline] |
| pub fn as_local(self) -> Option<LocalExpnId> { |
| if self.krate == LOCAL_CRATE { Some(LocalExpnId::from_raw(self.local_id)) } else { None } |
| } |
| |
| #[inline] |
| #[track_caller] |
| pub fn expect_local(self) -> LocalExpnId { |
| self.as_local().unwrap() |
| } |
| |
| #[inline] |
| pub fn expn_data(self) -> ExpnData { |
| HygieneData::with(|data| data.expn_data(self).clone()) |
| } |
| |
| #[inline] |
| pub fn is_descendant_of(self, ancestor: ExpnId) -> bool { |
| // a few "fast path" cases to avoid locking HygieneData |
| if ancestor == ExpnId::root() || ancestor == self { |
| return true; |
| } |
| if ancestor.krate != self.krate { |
| return false; |
| } |
| HygieneData::with(|data| data.is_descendant_of(self, ancestor)) |
| } |
| |
| /// `expn_id.outer_expn_is_descendant_of(ctxt)` is equivalent to but faster than |
| /// `expn_id.is_descendant_of(ctxt.outer_expn())`. |
| pub fn outer_expn_is_descendant_of(self, ctxt: SyntaxContext) -> bool { |
| HygieneData::with(|data| data.is_descendant_of(self, data.outer_expn(ctxt))) |
| } |
| |
| /// Returns span for the macro which originally caused this expansion to happen. |
| /// |
| /// Stops backtracing at include! boundary. |
| pub fn expansion_cause(mut self) -> Option<Span> { |
| let mut last_macro = None; |
| loop { |
| // Fast path to avoid locking. |
| if self == ExpnId::root() { |
| break; |
| } |
| let expn_data = self.expn_data(); |
| // Stop going up the backtrace once include! is encountered |
| if expn_data.kind == ExpnKind::Macro(MacroKind::Bang, sym::include) { |
| break; |
| } |
| self = expn_data.call_site.ctxt().outer_expn(); |
| last_macro = Some(expn_data.call_site); |
| } |
| last_macro |
| } |
| } |
| |
| #[derive(Debug)] |
| pub(crate) struct HygieneData { |
| /// Each expansion should have an associated expansion data, but sometimes there's a delay |
| /// between creation of an expansion ID and obtaining its data (e.g. macros are collected |
| /// first and then resolved later), so we use an `Option` here. |
| local_expn_data: IndexVec<LocalExpnId, Option<ExpnData>>, |
| local_expn_hashes: IndexVec<LocalExpnId, ExpnHash>, |
| /// Data and hash information from external crates. We may eventually want to remove these |
| /// maps, and fetch the information directly from the other crate's metadata like DefIds do. |
| foreign_expn_data: FxHashMap<ExpnId, ExpnData>, |
| foreign_expn_hashes: FxHashMap<ExpnId, ExpnHash>, |
| expn_hash_to_expn_id: UnhashMap<ExpnHash, ExpnId>, |
| syntax_context_data: Vec<SyntaxContextData>, |
| syntax_context_map: FxHashMap<SyntaxContextKey, SyntaxContext>, |
| /// Maps the `local_hash` of an `ExpnData` to the next disambiguator value. |
| /// This is used by `update_disambiguator` to keep track of which `ExpnData`s |
| /// would have collisions without a disambiguator. |
| /// The keys of this map are always computed with `ExpnData.disambiguator` |
| /// set to 0. |
| expn_data_disambiguators: UnhashMap<Hash64, u32>, |
| } |
| |
| impl HygieneData { |
| pub(crate) fn new(edition: Edition) -> Self { |
| let root_data = ExpnData::default( |
| ExpnKind::Root, |
| DUMMY_SP, |
| edition, |
| Some(CRATE_DEF_ID.to_def_id()), |
| None, |
| ); |
| |
| let root_ctxt_data = SyntaxContextData::root(); |
| HygieneData { |
| local_expn_data: IndexVec::from_elem_n(Some(root_data), 1), |
| local_expn_hashes: IndexVec::from_elem_n(ExpnHash(Fingerprint::ZERO), 1), |
| foreign_expn_data: FxHashMap::default(), |
| foreign_expn_hashes: FxHashMap::default(), |
| expn_hash_to_expn_id: iter::once((ExpnHash(Fingerprint::ZERO), ExpnId::root())) |
| .collect(), |
| syntax_context_data: vec![root_ctxt_data], |
| syntax_context_map: iter::once((root_ctxt_data.key(), SyntaxContext(0))).collect(), |
| expn_data_disambiguators: UnhashMap::default(), |
| } |
| } |
| |
| fn with<R>(f: impl FnOnce(&mut HygieneData) -> R) -> R { |
| with_session_globals(|session_globals| f(&mut session_globals.hygiene_data.borrow_mut())) |
| } |
| |
| #[inline] |
| fn expn_hash(&self, expn_id: ExpnId) -> ExpnHash { |
| match expn_id.as_local() { |
| Some(expn_id) => self.local_expn_hashes[expn_id], |
| None => self.foreign_expn_hashes[&expn_id], |
| } |
| } |
| |
| fn local_expn_data(&self, expn_id: LocalExpnId) -> &ExpnData { |
| self.local_expn_data[expn_id].as_ref().expect("no expansion data for an expansion ID") |
| } |
| |
| fn expn_data(&self, expn_id: ExpnId) -> &ExpnData { |
| if let Some(expn_id) = expn_id.as_local() { |
| self.local_expn_data[expn_id].as_ref().expect("no expansion data for an expansion ID") |
| } else { |
| &self.foreign_expn_data[&expn_id] |
| } |
| } |
| |
| fn is_descendant_of(&self, mut expn_id: ExpnId, ancestor: ExpnId) -> bool { |
| // a couple "fast path" cases to avoid traversing parents in the loop below |
| if ancestor == ExpnId::root() { |
| return true; |
| } |
| if expn_id.krate != ancestor.krate { |
| return false; |
| } |
| loop { |
| if expn_id == ancestor { |
| return true; |
| } |
| if expn_id == ExpnId::root() { |
| return false; |
| } |
| 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_semiopaque |
| } |
| |
| 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.is_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 { |
| let orig_span = span; |
| debug!("walk_chain({:?}, {:?})", span, to); |
| debug!("walk_chain: span ctxt = {:?}", span.ctxt()); |
| while span.ctxt() != to && span.from_expansion() { |
| 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; |
| } |
| debug!("walk_chain: for span {:?} >>> return span = {:?}", orig_span, span); |
| span |
| } |
| |
| fn walk_chain_collapsed(&self, mut span: Span, to: Span) -> Span { |
| let orig_span = span; |
| let mut ret_span = span; |
| debug!("walk_chain_collapsed({:?}, {:?})", span, to); |
| debug!("walk_chain_collapsed: span ctxt = {:?}", span.ctxt()); |
| while let ctxt = span.ctxt() |
| && !ctxt.is_root() |
| && ctxt != to.ctxt() |
| { |
| let outer_expn = self.outer_expn(ctxt); |
| debug!("walk_chain_collapsed({:?}): outer_expn={:?}", span, outer_expn); |
| let expn_data = self.expn_data(outer_expn); |
| debug!("walk_chain_collapsed({:?}): expn_data={:?}", span, expn_data); |
| span = expn_data.call_site; |
| if expn_data.collapse_debuginfo { |
| ret_span = span; |
| } |
| } |
| debug!("walk_chain_collapsed: for span {:?} >>> return span = {:?}", orig_span, ret_span); |
| ret_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.alloc_ctxt(ctxt, expn_id, transparency); |
| } |
| |
| let call_site_ctxt = self.expn_data(expn_id).call_site.ctxt(); |
| let mut call_site_ctxt = if transparency == Transparency::SemiOpaque { |
| 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.alloc_ctxt(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.alloc_ctxt(call_site_ctxt, expn_id, transparency); |
| } |
| self.alloc_ctxt(call_site_ctxt, expn_id, transparency) |
| } |
| |
| /// Allocate a new context with the given key, or retrieve it from cache if the given key |
| /// already exists. The auxiliary fields are calculated from the key. |
| fn alloc_ctxt( |
| &mut self, |
| parent: SyntaxContext, |
| expn_id: ExpnId, |
| transparency: Transparency, |
| ) -> SyntaxContext { |
| // Look into the cache first. |
| let key = (parent, expn_id, transparency); |
| if let Some(ctxt) = self.syntax_context_map.get(&key) { |
| return *ctxt; |
| } |
| |
| // Reserve a new syntax context. |
| // The inserted dummy data can only be potentially accessed by nested `alloc_ctxt` calls, |
| // the assert below ensures that it doesn't happen. |
| let ctxt = SyntaxContext::from_usize(self.syntax_context_data.len()); |
| self.syntax_context_data |
| .push(SyntaxContextData { dollar_crate_name: sym::dummy, ..SyntaxContextData::root() }); |
| self.syntax_context_map.insert(key, ctxt); |
| |
| // Opaque and semi-opaque versions of the parent. Note that they may be equal to the |
| // parent itself. E.g. `parent_opaque` == `parent` if the expn chain contains only opaques, |
| // and `parent_opaque_and_semiopaque` == `parent` if the expn contains only (semi-)opaques. |
| let parent_data = &self.syntax_context_data[parent.0 as usize]; |
| assert_ne!(parent_data.dollar_crate_name, sym::dummy); |
| let parent_opaque = parent_data.opaque; |
| let parent_opaque_and_semiopaque = parent_data.opaque_and_semiopaque; |
| |
| // Evaluate opaque and semi-opaque versions of the new syntax context. |
| let (opaque, opaque_and_semiopaque) = match transparency { |
| Transparency::Transparent => (parent_opaque, parent_opaque_and_semiopaque), |
| Transparency::SemiOpaque => ( |
| parent_opaque, |
| // Will be the same as `ctxt` if the expn chain contains only (semi-)opaques. |
| self.alloc_ctxt(parent_opaque_and_semiopaque, expn_id, transparency), |
| ), |
| Transparency::Opaque => ( |
| // Will be the same as `ctxt` if the expn chain contains only opaques. |
| self.alloc_ctxt(parent_opaque, expn_id, transparency), |
| // Will be the same as `ctxt` if the expn chain contains only (semi-)opaques. |
| self.alloc_ctxt(parent_opaque_and_semiopaque, expn_id, transparency), |
| ), |
| }; |
| |
| // Fill the full data, now that we have it. |
| self.syntax_context_data[ctxt.as_u32() as usize] = SyntaxContextData { |
| outer_expn: expn_id, |
| outer_transparency: transparency, |
| parent, |
| opaque, |
| opaque_and_semiopaque, |
| dollar_crate_name: kw::DollarCrate, |
| }; |
| ctxt |
| } |
| } |
| |
| pub fn walk_chain(span: Span, to: SyntaxContext) -> Span { |
| HygieneData::with(|data| data.walk_chain(span, to)) |
| } |
| |
| /// In order to have good line stepping behavior in debugger, for the given span we return its |
| /// outermost macro call site that still has a `#[collapse_debuginfo(yes)]` property on it. |
| /// We also stop walking call sites at the function body level because no line stepping can occur |
| /// at the level above that. |
| /// The returned span can then be used in emitted debuginfo. |
| pub fn walk_chain_collapsed(span: Span, to: Span) -> Span { |
| HygieneData::with(|data| data.walk_chain_collapsed(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 mut to_update = vec![]; |
| HygieneData::with(|data| { |
| for (idx, scdata) in data.syntax_context_data.iter().enumerate().rev() { |
| if scdata.dollar_crate_name == kw::DollarCrate { |
| to_update.push((idx, kw::DollarCrate)); |
| } else { |
| break; |
| } |
| } |
| }); |
| // The callback must be called from outside of the `HygieneData` lock, |
| // since it will try to acquire it too. |
| for (idx, name) in &mut to_update { |
| *name = get_name(SyntaxContext::from_usize(*idx)); |
| } |
| HygieneData::with(|data| { |
| for (idx, name) in to_update { |
| 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) |
| } |
| |
| #[inline] |
| pub(crate) const fn from_u16(raw: u16) -> SyntaxContext { |
| SyntaxContext(raw as u32) |
| } |
| |
| fn from_usize(raw: usize) -> SyntaxContext { |
| SyntaxContext(u32::try_from(raw).unwrap()) |
| } |
| |
| /// Extend a syntax context with a given expansion and transparency. |
| pub 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::$f`. |
| /// } |
| /// ``` |
| /// This returns the expansion whose definition scope we use to privacy check the resolution, |
| /// or `None` if we privacy check as usual (i.e., not w.r.t. a macro definition scope). |
| pub fn adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> { |
| HygieneData::with(|data| data.adjust(self, expn_id)) |
| } |
| |
| /// Like `SyntaxContext::adjust`, but also normalizes `self` to macros 2.0. |
| pub(crate) fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> { |
| HygieneData::with(|data| { |
| *self = data.normalize_to_macros_2_0(*self); |
| data.adjust(self, expn_id) |
| }) |
| } |
| |
| /// Adjust this context for resolution in a scope created by the given expansion |
| /// via a glob import with the given `SyntaxContext`. |
| /// For example: |
| /// |
| /// ```compile_fail,E0425 |
| /// #![feature(decl_macro)] |
| /// m!(f); |
| /// macro m($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(crate) 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(crate) 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] |
| fn outer_mark(self) -> (ExpnId, Transparency) { |
| HygieneData::with(|data| data.outer_mark(self)) |
| } |
| |
| pub(crate) 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) |
| } |
| |
| /// Returns whether this context originates in a foreign crate's external macro. |
| /// |
| /// This is used to test whether a lint should not even begin to figure out whether it should |
| /// be reported on the current node. |
| pub fn in_external_macro(self, sm: &SourceMap) -> bool { |
| let expn_data = self.outer_expn_data(); |
| match expn_data.kind { |
| ExpnKind::Root |
| | ExpnKind::Desugaring( |
| DesugaringKind::ForLoop |
| | DesugaringKind::WhileLoop |
| | DesugaringKind::OpaqueTy |
| | DesugaringKind::Async |
| | DesugaringKind::Await, |
| ) => false, |
| ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external" |
| ExpnKind::Macro(MacroKind::Bang, _) => { |
| // Dummy span for the `def_site` means it's an external macro. |
| expn_data.def_site.is_dummy() || sm.is_imported(expn_data.def_site) |
| } |
| ExpnKind::Macro { .. } => true, // definitely a plugin |
| } |
| } |
| } |
| |
| impl fmt::Debug for SyntaxContext { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| write!(f, "#{}", self.0) |
| } |
| } |
| |
| impl Span { |
| /// 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<Arc<[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.apply_mark(expn_id.to_expn_id(), Transparency::Transparent) |
| } |
| } |
| |
| /// 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<Arc<[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(crate) 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(crate) collapse_debuginfo: bool, |
| /// When true, we do not display the note telling people to use the `-Zmacro-backtrace` flag. |
| pub hide_backtrace: 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<Arc<[Symbol]>>, |
| edition: Edition, |
| macro_def_id: Option<DefId>, |
| parent_module: Option<DefId>, |
| allow_internal_unsafe: bool, |
| local_inner_macros: bool, |
| collapse_debuginfo: bool, |
| hide_backtrace: 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, |
| hide_backtrace, |
| } |
| } |
| |
| /// 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, |
| hide_backtrace: false, |
| } |
| } |
| |
| pub fn allow_unstable( |
| kind: ExpnKind, |
| call_site: Span, |
| edition: Edition, |
| allow_internal_unstable: Arc<[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 AST 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, PartialOrd, Ord, 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 { |
| 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, |
| /// `async Fn()` bound modifier |
| BoundModifier, |
| /// Calls to contract checks (`#[requires]` to precond, `#[ensures]` to postcond) |
| Contract, |
| /// A pattern type range start/end |
| PatTyRange, |
| /// A format literal. |
| FormatLiteral { |
| /// Was this format literal written in the source? |
| /// - `format!("boo")` => Yes, |
| /// - `format!(concat!("b", "o", "o"))` => No, |
| /// - `format!(include_str!("boo.txt"))` => No, |
| /// |
| /// If it wasn't written in the source then we have to be careful with suggestions about |
| /// rewriting it. |
| source: bool, |
| }, |
| } |
| |
| impl DesugaringKind { |
| /// The description wording should combine well with "desugaring of {}". |
| pub fn descr(self) -> &'static str { |
| match self { |
| 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", |
| DesugaringKind::BoundModifier => "trait bound modifier", |
| DesugaringKind::Contract => "contract check", |
| DesugaringKind::PatTyRange => "pattern type", |
| DesugaringKind::FormatLiteral { source: true } => "format string literal", |
| DesugaringKind::FormatLiteral { source: false } => { |
| "expression that expanded into a format string literal" |
| } |
| } |
| } |
| |
| /// For use with `rustc_unimplemented` to support conditions |
| /// like `from_desugaring = "QuestionMark"` |
| pub fn matches(&self, value: &str) -> bool { |
| match self { |
| DesugaringKind::Async => value == "Async", |
| DesugaringKind::Await => value == "Await", |
| DesugaringKind::QuestionMark => value == "QuestionMark", |
| DesugaringKind::TryBlock => value == "TryBlock", |
| DesugaringKind::YeetExpr => value == "YeetExpr", |
| DesugaringKind::OpaqueTy => value == "OpaqueTy", |
| DesugaringKind::ForLoop => value == "ForLoop", |
| DesugaringKind::WhileLoop => value == "WhileLoop", |
| DesugaringKind::BoundModifier => value == "BoundModifier", |
| DesugaringKind::Contract => value == "Contract", |
| DesugaringKind::PatTyRange => value == "PatTyRange", |
| DesugaringKind::FormatLiteral { .. } => value == "FormatLiteral", |
| } |
| } |
| } |
| |
| #[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, &SyntaxContextKey), |
| 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 syntax contexts. |
| // Drop the lock() temporary early. |
| // 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)] |
| let latest_ctxts = { mem::take(&mut *self.latest_ctxts.lock()) }.into_iter(); |
| let all_ctxt_data: Vec<_> = HygieneData::with(|data| { |
| latest_ctxts |
| .map(|ctxt| (ctxt, data.syntax_context_data[ctxt.0 as usize].key())) |
| .collect() |
| }); |
| for (ctxt, ctxt_key) in all_ctxt_data { |
| if self.serialized_ctxts.lock().insert(ctxt) { |
| encode_ctxt(encoder, ctxt.0, &ctxt_key); |
| } |
| } |
| |
| // Same as above, but for expansions instead of syntax contexts. |
| #[allow(rustc::potential_query_instability)] |
| let latest_expns = { mem::take(&mut *self.latest_expns.lock()) }.into_iter(); |
| let all_expn_data: Vec<_> = HygieneData::with(|data| { |
| latest_expns |
| .map(|expn| (expn, data.expn_data(expn).clone(), data.expn_hash(expn))) |
| .collect() |
| }); |
| for (expn, expn_data, expn_hash) in all_expn_data { |
| if self.serialized_expns.lock().insert(expn) { |
| encode_expn(encoder, expn, &expn_data, expn_hash); |
| } |
| } |
| } |
| debug!("encode_hygiene: Done serializing SyntaxContextData"); |
| } |
| } |
| |
| /// Additional information used to assist in decoding hygiene data |
| #[derive(Default)] |
| pub struct HygieneDecodeContext { |
| // A cache mapping raw serialized per-crate syntax context ids to corresponding decoded |
| // `SyntaxContext`s in the current global `HygieneData`. |
| remapped_ctxts: Lock<IndexVec<u32, Option<SyntaxContext>>>, |
| } |
| |
| /// 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); |
| 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>( |
| d: &mut D, |
| context: &HygieneDecodeContext, |
| decode_data: impl FnOnce(&mut D, u32) -> SyntaxContextKey, |
| ) -> 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(); |
| } |
| |
| // Look into the cache first. |
| // Reminder: `HygieneDecodeContext` is per-crate, so there are no collisions between |
| // raw ids from different crate metadatas. |
| if let Some(Some(ctxt)) = context.remapped_ctxts.lock().get(raw_id) { |
| return *ctxt; |
| } |
| |
| // Don't try to decode data while holding the lock, since we need to |
| // be able to recursively decode a SyntaxContext |
| let (parent, expn_id, transparency) = decode_data(d, raw_id); |
| let ctxt = |
| HygieneData::with(|hygiene_data| hygiene_data.alloc_ctxt(parent, expn_id, transparency)); |
| |
| context.remapped_ctxts.lock().insert(raw_id, ctxt); |
| |
| ctxt |
| } |
| |
| impl<E: SpanEncoder> Encodable<E> for LocalExpnId { |
| fn encode(&self, e: &mut E) { |
| self.to_expn_id().encode(e); |
| } |
| } |
| |
| impl<D: SpanDecoder> Decodable<D> for LocalExpnId { |
| fn decode(d: &mut D) -> Self { |
| ExpnId::expect_local(ExpnId::decode(d)) |
| } |
| } |
| |
| pub fn raw_encode_syntax_context( |
| ctxt: SyntaxContext, |
| context: &HygieneEncodeContext, |
| e: &mut impl Encoder, |
| ) { |
| if !context.serialized_ctxts.lock().contains(&ctxt) { |
| context.latest_ctxts.lock().insert(ctxt); |
| } |
| ctxt.0.encode(e); |
| } |
| |
| /// 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); |
| } |
| } |
