Auto merge of #123126 - oli-obk:feed_crate_num, r=davidtwco

Enable `CrateNum` query feeding via `TyCtxt`

Instead of having a magic function that violates some `TyCtxtFeed` invariants, add a `create_def` equivalent for `CrateNum`s.

Note that this still isn't tracked by the query system (unlike `create_def`), and that feeding most `CrateNum` queries for crates other than the local one will likely cause performance regressions.

These things should be attempted on their own separately, but this PR should stand on its own

compiler/rustc_metadata/src/creader.rs

@@ -13,10 +13,10 @@ use rustc_data_structures::sync::{self, FreezeReadGuard, FreezeWriteGuard};
 use rustc_errors::DiagCtxt;
 use rustc_expand::base::SyntaxExtension;
 use rustc_fs_util::try_canonicalize;
-use rustc_hir::def_id::{CrateNum, LocalDefId, StableCrateId, StableCrateIdMap, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, LocalDefId, StableCrateId, LOCAL_CRATE};
 use rustc_hir::definitions::Definitions;
 use rustc_index::IndexVec;
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{TyCtxt, TyCtxtFeed};
 use rustc_session::config::{self, CrateType, ExternLocation};
 use rustc_session::cstore::{CrateDepKind, CrateSource, ExternCrate, ExternCrateSource};
 use rustc_session::lint;
@@ -62,9 +62,6 @@ pub struct CStore {
     /// This crate has a `#[alloc_error_handler]` item.
     has_alloc_error_handler: bool,
 
-    /// The interned [StableCrateId]s.
-    pub(crate) stable_crate_ids: StableCrateIdMap,
-
     /// Unused externs of the crate
     unused_externs: Vec<Symbol>,
 }
@@ -165,25 +162,27 @@ impl CStore {
         })
     }
 
-    fn intern_stable_crate_id(&mut self, root: &CrateRoot) -> Result<CrateNum, CrateError> {
-        assert_eq!(self.metas.len(), self.stable_crate_ids.len());
-        let num = CrateNum::new(self.stable_crate_ids.len());
-        if let Some(&existing) = self.stable_crate_ids.get(&root.stable_crate_id()) {
+    fn intern_stable_crate_id<'tcx>(
+        &mut self,
+        root: &CrateRoot,
+        tcx: TyCtxt<'tcx>,
+    ) -> Result<TyCtxtFeed<'tcx, CrateNum>, CrateError> {
+        assert_eq!(self.metas.len(), tcx.untracked().stable_crate_ids.read().len());
+        let num = tcx.create_crate_num(root.stable_crate_id()).map_err(|existing| {
             // Check for (potential) conflicts with the local crate
             if existing == LOCAL_CRATE {
-                Err(CrateError::SymbolConflictsCurrent(root.name()))
+                CrateError::SymbolConflictsCurrent(root.name())
             } else if let Some(crate_name1) = self.metas[existing].as_ref().map(|data| data.name())
             {
                 let crate_name0 = root.name();
-                Err(CrateError::StableCrateIdCollision(crate_name0, crate_name1))
+                CrateError::StableCrateIdCollision(crate_name0, crate_name1)
             } else {
-                Err(CrateError::NotFound(root.name()))
+                CrateError::NotFound(root.name())
             }
-        } else {
-            self.metas.push(None);
-            self.stable_crate_ids.insert(root.stable_crate_id(), num);
-            Ok(num)
-        }
+        })?;
+
+        self.metas.push(None);
+        Ok(num)
     }
 
     pub fn has_crate_data(&self, cnum: CrateNum) -> bool {
@@ -289,12 +288,7 @@ impl CStore {
         }
     }
 
-    pub fn new(
-        metadata_loader: Box<MetadataLoaderDyn>,
-        local_stable_crate_id: StableCrateId,
-    ) -> CStore {
-        let mut stable_crate_ids = StableCrateIdMap::default();
-        stable_crate_ids.insert(local_stable_crate_id, LOCAL_CRATE);
+    pub fn new(metadata_loader: Box<MetadataLoaderDyn>) -> CStore {
         CStore {
             metadata_loader,
             // We add an empty entry for LOCAL_CRATE (which maps to zero) in
@@ -307,7 +301,6 @@ impl CStore {
             alloc_error_handler_kind: None,
             has_global_allocator: false,
             has_alloc_error_handler: false,
-            stable_crate_ids,
             unused_externs: Vec::new(),
         }
     }
@@ -416,7 +409,8 @@ impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
         let private_dep = self.is_private_dep(name.as_str(), private_dep);
 
         // Claim this crate number and cache it
-        let cnum = self.cstore.intern_stable_crate_id(&crate_root)?;
+        let feed = self.cstore.intern_stable_crate_id(&crate_root, self.tcx)?;
+        let cnum = feed.key();
 
         info!(
             "register crate `{}` (cnum = {}. private_dep = {})",

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -629,13 +629,6 @@ impl CrateStore for CStore {
         self.get_crate_data(cnum).root.stable_crate_id
     }
 
-    fn stable_crate_id_to_crate_num(&self, stable_crate_id: StableCrateId) -> CrateNum {
-        *self
-            .stable_crate_ids
-            .get(&stable_crate_id)
-            .unwrap_or_else(|| bug!("uninterned StableCrateId: {stable_crate_id:?}"))
-    }
-
     /// Returns the `DefKey` for a given `DefId`. This indicates the
     /// parent `DefId` as well as some idea of what kind of data the
     /// `DefId` refers to.
@@ -657,7 +650,13 @@ fn provide_cstore_hooks(providers: &mut Providers) {
         // If this is a DefPathHash from an upstream crate, let the CrateStore map
         // it to a DefId.
         let cstore = CStore::from_tcx(tcx.tcx);
-        let cnum = cstore.stable_crate_id_to_crate_num(stable_crate_id);
+        let cnum = *tcx
+            .untracked()
+            .stable_crate_ids
+            .read()
+            .get(&stable_crate_id)
+            .unwrap_or_else(|| bug!("uninterned StableCrateId: {stable_crate_id:?}"));
+        assert_ne!(cnum, LOCAL_CRATE);
         let def_index = cstore.get_crate_data(cnum).def_path_hash_to_def_index(hash);
         DefId { krate: cnum, index: def_index }
     };