Auto merge of #86676 - cjgillot:localexpn, r=petrochenkov

Make expansions stable for incr. comp.

This PR aims to make expansions stable for incr. comp. by using the same architecture as definitions:
- the interned identifier `ExpnId` contains a `CrateNum` and a crate-local id;
- bidirectional maps `ExpnHash <-> ExpnId` are setup;
- incr. comp. on-disk cache saves and reconstructs expansions using their `ExpnHash`.

I tried to use as many `LocalExpnId` as I could in the resolver code, but I may have missed a few opportunities.

All this will allow to use an `ExpnId` as a query key, and to force this query without recomputing caller queries. For instance, this will be used to implement #85999.

r? `@petrochenkov`

Author: bors

compiler/rustc_ast/src/node_id.rs

@@ -1,4 +1,4 @@
-use rustc_span::ExpnId;
+use rustc_span::LocalExpnId;
 use std::fmt;
 
 rustc_index::newtype_index! {
@@ -24,12 +24,12 @@ pub const CRATE_NODE_ID: NodeId = NodeId::from_u32(0);
 pub const DUMMY_NODE_ID: NodeId = NodeId::MAX;
 
 impl NodeId {
-    pub fn placeholder_from_expn_id(expn_id: ExpnId) -> Self {
+    pub fn placeholder_from_expn_id(expn_id: LocalExpnId) -> Self {
         NodeId::from_u32(expn_id.as_u32())
     }
 
-    pub fn placeholder_to_expn_id(self) -> ExpnId {
-        ExpnId::from_u32(self.as_u32())
+    pub fn placeholder_to_expn_id(self) -> LocalExpnId {
+        LocalExpnId::from_u32(self.as_u32())
     }
 }
 

compiler/rustc_builtin_macros/src/deriving/clone.rs

@@ -36,8 +36,9 @@ pub fn expand_deriving_clone(
         Annotatable::Item(ref annitem) => match annitem.kind {
             ItemKind::Struct(_, Generics { ref params, .. })
             | ItemKind::Enum(_, Generics { ref params, .. }) => {
-                let container_id = cx.current_expansion.id.expn_data().parent;
-                if cx.resolver.has_derive_copy(container_id)
+                let container_id = cx.current_expansion.id.expn_data().parent.expect_local();
+                let has_derive_copy = cx.resolver.has_derive_copy(container_id);
+                if has_derive_copy
                     && !params
                         .iter()
                         .any(|param| matches!(param.kind, ast::GenericParamKind::Type { .. }))

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -410,7 +410,7 @@ impl<'a> TraitDef<'a> {
                         .any(|param| matches!(param.kind, ast::GenericParamKind::Type { .. })),
                     _ => unreachable!(),
                 };
-                let container_id = cx.current_expansion.id.expn_data().parent;
+                let container_id = cx.current_expansion.id.expn_data().parent.expect_local();
                 let always_copy = has_no_type_params && cx.resolver.has_derive_copy(container_id);
                 let use_temporaries = is_packed && always_copy;
 

compiler/rustc_builtin_macros/src/proc_macro_harness.rs

@@ -304,7 +304,7 @@ fn mk_decls(
         &[sym::rustc_attrs, sym::proc_macro_internals],
         None,
     );
-    let span = DUMMY_SP.with_def_site_ctxt(expn_id);
+    let span = DUMMY_SP.with_def_site_ctxt(expn_id.to_expn_id());
 
     let proc_macro = Ident::new(sym::proc_macro, span);
     let krate = cx.item(span, proc_macro, Vec::new(), ast::ItemKind::ExternCrate(None));

compiler/rustc_builtin_macros/src/standard_library_imports.rs

@@ -34,8 +34,8 @@ pub fn inject(
         &[sym::prelude_import],
         None,
     );
-    let span = DUMMY_SP.with_def_site_ctxt(expn_id);
-    let call_site = DUMMY_SP.with_call_site_ctxt(expn_id);
+    let span = DUMMY_SP.with_def_site_ctxt(expn_id.to_expn_id());
+    let call_site = DUMMY_SP.with_call_site_ctxt(expn_id.to_expn_id());
 
     let ecfg = ExpansionConfig::default("std_lib_injection".to_string());
     let cx = ExtCtxt::new(sess, ecfg, resolver, None);

compiler/rustc_builtin_macros/src/test_harness.rs

@@ -126,7 +126,8 @@ impl<'a> MutVisitor for TestHarnessGenerator<'a> {
                 for test in &mut tests {
                     // See the comment on `mk_main` for why we're using
                     // `apply_mark` directly.
-                    test.ident.span = test.ident.span.apply_mark(expn_id, Transparency::Opaque);
+                    test.ident.span =
+                        test.ident.span.apply_mark(expn_id.to_expn_id(), Transparency::Opaque);
                 }
                 self.cx.test_cases.extend(tests);
             }
@@ -223,7 +224,7 @@ fn generate_test_harness(
         &[sym::test, sym::rustc_attrs],
         None,
     );
-    let def_site = DUMMY_SP.with_def_site_ctxt(expn_id);
+    let def_site = DUMMY_SP.with_def_site_ctxt(expn_id.to_expn_id());
 
     // Remove the entry points
     let mut cleaner = EntryPointCleaner { sess, depth: 0, def_site };

compiler/rustc_expand/src/base.rs

@@ -16,7 +16,7 @@ use rustc_parse::{self, nt_to_tokenstream, parser, MACRO_ARGUMENTS};
 use rustc_session::{parse::ParseSess, Limit, Session};
 use rustc_span::def_id::{CrateNum, DefId};
 use rustc_span::edition::Edition;
-use rustc_span::hygiene::{AstPass, ExpnData, ExpnId, ExpnKind};
+use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{FileName, MultiSpan, Span, DUMMY_SP};
@@ -813,15 +813,15 @@ impl SyntaxExtension {
 
     pub fn expn_data(
         &self,
-        parent: ExpnId,
+        parent: LocalExpnId,
         call_site: Span,
         descr: Symbol,
         macro_def_id: Option<DefId>,
         parent_module: Option<DefId>,
     ) -> ExpnData {
         ExpnData::new(
             ExpnKind::Macro(self.macro_kind(), descr),
-            parent,
+            parent.to_expn_id(),
             call_site,
             self.span,
             self.allow_internal_unstable.clone(),
@@ -843,7 +843,11 @@ pub trait ResolverExpand {
     fn next_node_id(&mut self) -> NodeId;
 
     fn resolve_dollar_crates(&mut self);
-    fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment);
+    fn visit_ast_fragment_with_placeholders(
+        &mut self,
+        expn_id: LocalExpnId,
+        fragment: &AstFragment,
+    );
     fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind);
 
     fn expansion_for_ast_pass(
@@ -852,37 +856,41 @@ pub trait ResolverExpand {
         pass: AstPass,
         features: &[Symbol],
         parent_module_id: Option<NodeId>,
-    ) -> ExpnId;
+    ) -> LocalExpnId;
 
     fn resolve_imports(&mut self);
 
     fn resolve_macro_invocation(
         &mut self,
         invoc: &Invocation,
-        eager_expansion_root: ExpnId,
+        eager_expansion_root: LocalExpnId,
         force: bool,
     ) -> Result<Lrc<SyntaxExtension>, Indeterminate>;
 
     fn check_unused_macros(&mut self);
 
     /// Some parent node that is close enough to the given macro call.
-    fn lint_node_id(&self, expn_id: ExpnId) -> NodeId;
+    fn lint_node_id(&self, expn_id: LocalExpnId) -> NodeId;
 
     // Resolver interfaces for specific built-in macros.
     /// Does `#[derive(...)]` attribute with the given `ExpnId` have built-in `Copy` inside it?
-    fn has_derive_copy(&self, expn_id: ExpnId) -> bool;
+    fn has_derive_copy(&self, expn_id: LocalExpnId) -> bool;
     /// Resolve paths inside the `#[derive(...)]` attribute with the given `ExpnId`.
     fn resolve_derives(
         &mut self,
-        expn_id: ExpnId,
+        expn_id: LocalExpnId,
         force: bool,
         derive_paths: &dyn Fn() -> DeriveResolutions,
     ) -> Result<(), Indeterminate>;
     /// Take resolutions for paths inside the `#[derive(...)]` attribute with the given `ExpnId`
     /// back from resolver.
-    fn take_derive_resolutions(&mut self, expn_id: ExpnId) -> Option<DeriveResolutions>;
+    fn take_derive_resolutions(&mut self, expn_id: LocalExpnId) -> Option<DeriveResolutions>;
     /// Path resolution logic for `#[cfg_accessible(path)]`.
-    fn cfg_accessible(&mut self, expn_id: ExpnId, path: &ast::Path) -> Result<bool, Indeterminate>;
+    fn cfg_accessible(
+        &mut self,
+        expn_id: LocalExpnId,
+        path: &ast::Path,
+    ) -> Result<bool, Indeterminate>;
 
     /// Decodes the proc-macro quoted span in the specified crate, with the specified id.
     /// No caching is performed.
@@ -913,7 +921,7 @@ impl ModuleData {
 
 #[derive(Clone)]
 pub struct ExpansionData {
-    pub id: ExpnId,
+    pub id: LocalExpnId,
     pub depth: usize,
     pub module: Rc<ModuleData>,
     pub dir_ownership: DirOwnership,
@@ -958,7 +966,7 @@ impl<'a> ExtCtxt<'a> {
             extern_mod_loaded,
             root_path: PathBuf::new(),
             current_expansion: ExpansionData {
-                id: ExpnId::root(),
+                id: LocalExpnId::ROOT,
                 depth: 0,
                 module: Default::default(),
                 dir_ownership: DirOwnership::Owned { relative: None },
@@ -995,19 +1003,19 @@ impl<'a> ExtCtxt<'a> {
     /// Equivalent of `Span::def_site` from the proc macro API,
     /// except that the location is taken from the span passed as an argument.
     pub fn with_def_site_ctxt(&self, span: Span) -> Span {
-        span.with_def_site_ctxt(self.current_expansion.id)
+        span.with_def_site_ctxt(self.current_expansion.id.to_expn_id())
     }
 
     /// Equivalent of `Span::call_site` from the proc macro API,
     /// except that the location is taken from the span passed as an argument.
     pub fn with_call_site_ctxt(&self, span: Span) -> Span {
-        span.with_call_site_ctxt(self.current_expansion.id)
+        span.with_call_site_ctxt(self.current_expansion.id.to_expn_id())
     }
 
     /// Equivalent of `Span::mixed_site` from the proc macro API,
     /// except that the location is taken from the span passed as an argument.
     pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
-        span.with_mixed_site_ctxt(self.current_expansion.id)
+        span.with_mixed_site_ctxt(self.current_expansion.id.to_expn_id())
     }
 
     /// Returns span for the macro which originally caused the current expansion to happen.

compiler/rustc_expand/src/expand.rs

@@ -31,7 +31,7 @@ use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::parse::{feature_err, ParseSess};
 use rustc_session::Limit;
 use rustc_span::symbol::{sym, Ident};
-use rustc_span::{ExpnId, FileName, Span};
+use rustc_span::{FileName, LocalExpnId, Span};
 
 use smallvec::{smallvec, SmallVec};
 use std::ops::DerefMut;
@@ -508,7 +508,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                 .map(|(path, item, _exts)| {
                                     // FIXME: Consider using the derive resolutions (`_exts`)
                                     // instead of enqueuing the derives to be resolved again later.
-                                    let expn_id = ExpnId::fresh_empty();
+                                    let expn_id = LocalExpnId::fresh_empty();
                                     derive_invocations.push((
                                         Invocation {
                                             kind: InvocationKind::Derive { path, item },
@@ -993,7 +993,7 @@ struct InvocationCollector<'a, 'b> {
 
 impl<'a, 'b> InvocationCollector<'a, 'b> {
     fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
-        let expn_id = ExpnId::fresh_empty();
+        let expn_id = LocalExpnId::fresh_empty();
         let vis = kind.placeholder_visibility();
         self.invocations.push((
             Invocation {

compiler/rustc_expand/src/mbe/transcribe.rs

@@ -8,23 +8,23 @@ use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndSpacing};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{pluralize, PResult};
-use rustc_span::hygiene::{ExpnId, Transparency};
+use rustc_span::hygiene::{LocalExpnId, Transparency};
 use rustc_span::symbol::MacroRulesNormalizedIdent;
 use rustc_span::Span;
 
 use smallvec::{smallvec, SmallVec};
 use std::mem;
 
 // A Marker adds the given mark to the syntax context.
-struct Marker(ExpnId, Transparency);
+struct Marker(LocalExpnId, Transparency);
 
 impl MutVisitor for Marker {
     fn token_visiting_enabled(&self) -> bool {
         true
     }
 
     fn visit_span(&mut self, span: &mut Span) {
-        *span = span.apply_mark(self.0, self.1)
+        *span = span.apply_mark(self.0.to_expn_id(), self.1)
     }
 }