Allow to create definitions inside the query system.

Author: cjgillot

compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs

@@ -93,8 +93,9 @@ impl<'tcx> UniqueTypeId<'tcx> {
     /// Right now this takes the form of a hex-encoded opaque hash value.
     pub fn generate_unique_id_string(self, tcx: TyCtxt<'tcx>) -> String {
         let mut hasher = StableHasher::new();
-        let mut hcx = tcx.create_stable_hashing_context();
-        hcx.while_hashing_spans(false, |hcx| self.hash_stable(hcx, &mut hasher));
+        tcx.with_stable_hashing_context(|mut hcx| {
+            hcx.while_hashing_spans(false, |hcx| self.hash_stable(hcx, &mut hasher))
+        });
         hasher.finish::<Fingerprint>().to_hex()
     }
 

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -701,16 +701,20 @@ fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut S
                 // If we cannot evaluate the constant to a known type, we fall back
                 // to emitting a stable hash value of the constant. This isn't very pretty
                 // but we get a deterministic, virtually unique value for the constant.
-                let hcx = &mut tcx.create_stable_hashing_context();
-                let mut hasher = StableHasher::new();
-                let ct = ct.eval(tcx, ty::ParamEnv::reveal_all());
-                hcx.while_hashing_spans(false, |hcx| ct.to_valtree().hash_stable(hcx, &mut hasher));
+                //
                 // Let's only emit 64 bits of the hash value. That should be plenty for
                 // avoiding collisions and will make the emitted type names shorter.
-                // Note: Don't use `StableHashResult` impl of `u64` here directly, since that
-                // would lead to endianness problems.
-                let hash: u128 = hasher.finish();
-                let hash_short = (hash.to_le() as u64).to_le();
+                let hash_short = tcx.with_stable_hashing_context(|mut hcx| {
+                    let mut hasher = StableHasher::new();
+                    let ct = ct.eval(tcx, ty::ParamEnv::reveal_all());
+                    hcx.while_hashing_spans(false, |hcx| {
+                        ct.to_valtree().hash_stable(hcx, &mut hasher)
+                    });
+                    // Note: Don't use `StableHashResult` impl of `u64` here directly, since that
+                    // would lead to endianness problems.
+                    let hash: u128 = hasher.finish();
+                    (hash.to_le() as u64).to_le()
+                });
 
                 if cpp_like_debuginfo(tcx) {
                     write!(output, "CONST${:x}", hash_short)

compiler/rustc_data_structures/src/lib.rs

@@ -10,6 +10,7 @@
 #![feature(array_windows)]
 #![feature(associated_type_bounds)]
 #![feature(auto_traits)]
+#![feature(cell_leak)]
 #![feature(control_flow_enum)]
 #![feature(extend_one)]
 #![feature(let_else)]

compiler/rustc_data_structures/src/sync.rs

@@ -539,6 +539,33 @@ impl<T> RwLock<T> {
     pub fn borrow_mut(&self) -> WriteGuard<'_, T> {
         self.write()
     }
+
+    #[cfg(not(parallel_compiler))]
+    #[inline(always)]
+    pub fn clone_guard<'a>(rg: &ReadGuard<'a, T>) -> ReadGuard<'a, T> {
+        ReadGuard::clone(rg)
+    }
+
+    #[cfg(parallel_compiler)]
+    #[inline(always)]
+    pub fn clone_guard<'a>(rg: &ReadGuard<'a, T>) -> ReadGuard<'a, T> {
+        ReadGuard::rwlock(&rg).read()
+    }
+
+    #[cfg(not(parallel_compiler))]
+    #[inline(always)]
+    pub fn leak(&self) -> &T {
+        ReadGuard::leak(self.read())
+    }
+
+    #[cfg(parallel_compiler)]
+    #[inline(always)]
+    pub fn leak(&self) -> &T {
+        let guard = self.read();
+        let ret = unsafe { &*(&*guard as *const T) };
+        std::mem::forget(guard);
+        ret
+    }
 }
 
 // FIXME: Probably a bad idea

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -423,7 +423,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     }
 
     fn encode_def_path_table(&mut self) {
-        let table = self.tcx.definitions_untracked().def_path_table();
+        let table = self.tcx.def_path_table();
         if self.is_proc_macro {
             for def_index in std::iter::once(CRATE_DEF_INDEX)
                 .chain(self.tcx.resolutions(()).proc_macros.iter().map(|p| p.local_def_index))
@@ -443,9 +443,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     }
 
     fn encode_def_path_hash_map(&mut self) -> LazyValue<DefPathHashMapRef<'static>> {
-        self.lazy(DefPathHashMapRef::BorrowedFromTcx(
-            self.tcx.definitions_untracked().def_path_hash_to_def_index_map(),
-        ))
+        self.lazy(DefPathHashMapRef::BorrowedFromTcx(self.tcx.def_path_hash_to_def_index_map()))
     }
 
     fn encode_source_map(&mut self) -> LazyArray<rustc_span::SourceFile> {
@@ -614,7 +612,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         let interpret_alloc_index_bytes = self.position() - i;
 
         // Encode the proc macro data. This affects 'tables',
-        // so we need to do this before we encode the tables
+        // so we need to do this before we encode the tables.
+        // This overwrites def_keys, so it must happen after encode_def_path_table.
         i = self.position();
         let proc_macro_data = self.encode_proc_macros();
         let proc_macro_data_bytes = self.position() - i;
@@ -992,8 +991,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             return;
         }
         let tcx = self.tcx;
-        let hir = tcx.hir();
-        for local_id in hir.iter_local_def_id() {
+        for local_id in tcx.iter_local_def_id() {
             let def_id = local_id.to_def_id();
             let def_kind = tcx.opt_def_kind(local_id);
             let Some(def_kind) = def_kind else { continue };
@@ -1854,12 +1852,13 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         debug!("EncodeContext::encode_traits_and_impls()");
         empty_proc_macro!(self);
         let tcx = self.tcx;
-        let mut ctx = tcx.create_stable_hashing_context();
         let mut all_impls: Vec<_> = tcx.crate_inherent_impls(()).incoherent_impls.iter().collect();
-        all_impls.sort_by_cached_key(|&(&simp, _)| {
-            let mut hasher = StableHasher::new();
-            simp.hash_stable(&mut ctx, &mut hasher);
-            hasher.finish::<Fingerprint>();
+        tcx.with_stable_hashing_context(|mut ctx| {
+            all_impls.sort_by_cached_key(|&(&simp, _)| {
+                let mut hasher = StableHasher::new();
+                simp.hash_stable(&mut ctx, &mut hasher);
+                hasher.finish::<Fingerprint>()
+            })
         });
         let all_impls: Vec<_> = all_impls
             .into_iter()

compiler/rustc_middle/src/dep_graph/mod.rs

@@ -71,8 +71,8 @@ impl<'tcx> DepContext for TyCtxt<'tcx> {
     type DepKind = DepKind;
 
     #[inline]
-    fn create_stable_hashing_context(&self) -> StableHashingContext<'_> {
-        TyCtxt::create_stable_hashing_context(*self)
+    fn with_stable_hashing_context<R>(&self, f: impl FnOnce(StableHashingContext<'_>) -> R) -> R {
+        TyCtxt::with_stable_hashing_context(*self, f)
     }
 
     #[inline]

compiler/rustc_middle/src/hir/map/mod.rs

@@ -218,13 +218,6 @@ impl<'hir> Map<'hir> {
         self.tcx.local_def_id_to_hir_id(def_id)
     }
 
-    pub fn iter_local_def_id(self) -> impl Iterator<Item = LocalDefId> + 'hir {
-        // Create a dependency to the crate to be sure we re-execute this when the amount of
-        // definitions change.
-        self.tcx.ensure().hir_crate(());
-        self.tcx.definitions_untracked().iter_local_def_id()
-    }
-
     /// Do not call this function directly. The query should be called.
     pub(super) fn opt_def_kind(self, local_def_id: LocalDefId) -> Option<DefKind> {
         let hir_id = self.local_def_id_to_hir_id(local_def_id);
@@ -1141,34 +1134,35 @@ pub(super) fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
 
     source_file_names.sort_unstable();
 
-    let mut hcx = tcx.create_stable_hashing_context();
-    let mut stable_hasher = StableHasher::new();
-    hir_body_hash.hash_stable(&mut hcx, &mut stable_hasher);
-    upstream_crates.hash_stable(&mut hcx, &mut stable_hasher);
-    source_file_names.hash_stable(&mut hcx, &mut stable_hasher);
-    if tcx.sess.opts.debugging_opts.incremental_relative_spans {
-        let definitions = &tcx.definitions_untracked();
-        let mut owner_spans: Vec<_> = krate
-            .owners
-            .iter_enumerated()
-            .filter_map(|(def_id, info)| {
-                let _ = info.as_owner()?;
-                let def_path_hash = definitions.def_path_hash(def_id);
-                let span = resolutions.source_span[def_id];
-                debug_assert_eq!(span.parent(), None);
-                Some((def_path_hash, span))
-            })
-            .collect();
-        owner_spans.sort_unstable_by_key(|bn| bn.0);
-        owner_spans.hash_stable(&mut hcx, &mut stable_hasher);
-    }
-    tcx.sess.opts.dep_tracking_hash(true).hash_stable(&mut hcx, &mut stable_hasher);
-    tcx.sess.local_stable_crate_id().hash_stable(&mut hcx, &mut stable_hasher);
-    // Hash visibility information since it does not appear in HIR.
-    resolutions.visibilities.hash_stable(&mut hcx, &mut stable_hasher);
-    resolutions.has_pub_restricted.hash_stable(&mut hcx, &mut stable_hasher);
+    let crate_hash: Fingerprint = tcx.with_stable_hashing_context(|mut hcx| {
+        let mut stable_hasher = StableHasher::new();
+        hir_body_hash.hash_stable(&mut hcx, &mut stable_hasher);
+        upstream_crates.hash_stable(&mut hcx, &mut stable_hasher);
+        source_file_names.hash_stable(&mut hcx, &mut stable_hasher);
+        if tcx.sess.opts.debugging_opts.incremental_relative_spans {
+            let definitions = tcx.definitions_untracked();
+            let mut owner_spans: Vec<_> = krate
+                .owners
+                .iter_enumerated()
+                .filter_map(|(def_id, info)| {
+                    let _ = info.as_owner()?;
+                    let def_path_hash = definitions.def_path_hash(def_id);
+                    let span = resolutions.source_span[def_id];
+                    debug_assert_eq!(span.parent(), None);
+                    Some((def_path_hash, span))
+                })
+                .collect();
+            owner_spans.sort_unstable_by_key(|bn| bn.0);
+            owner_spans.hash_stable(&mut hcx, &mut stable_hasher);
+        }
+        tcx.sess.opts.dep_tracking_hash(true).hash_stable(&mut hcx, &mut stable_hasher);
+        tcx.sess.local_stable_crate_id().hash_stable(&mut hcx, &mut stable_hasher);
+        // Hash visibility information since it does not appear in HIR.
+        resolutions.visibilities.hash_stable(&mut hcx, &mut stable_hasher);
+        resolutions.has_pub_restricted.hash_stable(&mut hcx, &mut stable_hasher);
+        stable_hasher.finish()
+    });
 
-    let crate_hash: Fingerprint = stable_hasher.finish();
     Svh::new(crate_hash.to_smaller_hash())
 }
 

compiler/rustc_middle/src/query/mod.rs

@@ -20,6 +20,12 @@ rustc_queries! {
         desc { "trigger a delay span bug" }
     }
 
+    /// Create a new definition within the incr. comp. engine.
+    query register_def(_: ty::RawLocalDefId) -> LocalDefId {
+        eval_always
+        desc { "register a DefId with the incr. comp. engine" }
+    }
+
     query resolutions(_: ()) -> &'tcx ty::ResolverOutputs {
         eval_always
         no_hash