Move some code from Compiler::enter to GlobalCtxt::finish

compiler/rustc_incremental/src/lib.rs

@@ -16,8 +16,15 @@ mod persist;
 
 pub use persist::{
     LoadResult, copy_cgu_workproduct_to_incr_comp_cache_dir, finalize_session_directory,
-    in_incr_comp_dir, in_incr_comp_dir_sess, load_query_result_cache, save_dep_graph,
-    save_work_product_index, setup_dep_graph,
+    in_incr_comp_dir, in_incr_comp_dir_sess, load_query_result_cache, save_work_product_index,
+    setup_dep_graph,
 };
+use rustc_middle::util::Providers;
+
+#[allow(missing_docs)]
+pub fn provide(providers: &mut Providers) {
+    providers.hooks.save_dep_graph =
+        |tcx| tcx.sess.time("serialize_dep_graph", || persist::save_dep_graph(tcx.tcx));
+}
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }

compiler/rustc_incremental/src/persist/mod.rs

@@ -12,5 +12,6 @@ mod work_product;
 
 pub use fs::{finalize_session_directory, in_incr_comp_dir, in_incr_comp_dir_sess};
 pub use load::{LoadResult, load_query_result_cache, setup_dep_graph};
-pub use save::{save_dep_graph, save_work_product_index};
+pub(crate) use save::save_dep_graph;
+pub use save::save_work_product_index;
 pub use work_product::copy_cgu_workproduct_to_incr_comp_cache_dir;

compiler/rustc_incremental/src/persist/save.rs

@@ -25,7 +25,7 @@ use crate::errors;
 ///
 /// This function should only run after all queries have completed.
 /// Trying to execute a query afterwards would attempt to read the result cache we just dropped.
-pub fn save_dep_graph(tcx: TyCtxt<'_>) {
+pub(crate) fn save_dep_graph(tcx: TyCtxt<'_>) {
     debug!("save_dep_graph()");
     tcx.dep_graph.with_ignore(|| {
         let sess = tcx.sess;

compiler/rustc_interface/src/passes.rs

@@ -704,10 +704,12 @@ pub static DEFAULT_QUERY_PROVIDERS: LazyLock<Providers> = LazyLock::new(|| {
     rustc_const_eval::provide(providers);
     rustc_middle::hir::provide(providers);
     rustc_borrowck::provide(providers);
+    rustc_incremental::provide(providers);
     rustc_mir_build::provide(providers);
     rustc_mir_transform::provide(providers);
     rustc_monomorphize::provide(providers);
     rustc_privacy::provide(providers);
+    rustc_query_impl::provide(providers);
     rustc_resolve::provide(providers);
     rustc_hir_analysis::provide(providers);
     rustc_hir_typeck::provide(providers);

compiler/rustc_interface/src/queries.rs

@@ -12,13 +12,12 @@ use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::arena::Arena;
 use rustc_middle::dep_graph::DepGraph;
 use rustc_middle::ty::{GlobalCtxt, TyCtxt};
-use rustc_serialize::opaque::FileEncodeResult;
 use rustc_session::Session;
 use rustc_session::config::{self, OutputFilenames, OutputType};
 
 use crate::errors::FailedWritingFile;
 use crate::interface::{Compiler, Result};
-use crate::{errors, passes};
+use crate::passes;
 
 /// Represent the result of a query.
 ///
@@ -90,8 +89,10 @@ impl<'tcx> Queries<'tcx> {
         }
     }
 
-    pub fn finish(&self) -> FileEncodeResult {
-        if let Some(gcx) = self.gcx_cell.get() { gcx.finish() } else { Ok(0) }
+    pub fn finish(&'tcx self) {
+        if let Some(gcx) = self.gcx_cell.get() {
+            gcx.finish();
+        }
     }
 
     pub fn parse(&self) -> Result<QueryResult<'_, ast::Crate>> {
@@ -209,29 +210,10 @@ impl Compiler {
         let queries = Queries::new(self);
         let ret = f(&queries);
 
-        // NOTE: intentionally does not compute the global context if it hasn't been built yet,
-        // since that likely means there was a parse error.
-        if let Some(Ok(gcx)) = &mut *queries.gcx.result.borrow_mut() {
-            let gcx = gcx.get_mut();
-            // We assume that no queries are run past here. If there are new queries
-            // after this point, they'll show up as "<unknown>" in self-profiling data.
-            {
-                let _prof_timer =
-                    queries.compiler.sess.prof.generic_activity("self_profile_alloc_query_strings");
-                gcx.enter(rustc_query_impl::alloc_self_profile_query_strings);
-            }
-
-            self.sess.time("serialize_dep_graph", || gcx.enter(rustc_incremental::save_dep_graph));
-
-            gcx.enter(rustc_query_impl::query_key_hash_verify_all);
-        }
-
         // The timer's lifetime spans the dropping of `queries`, which contains
         // the global context.
         _timer = self.sess.timer("free_global_ctxt");
-        if let Err((path, error)) = queries.finish() {
-            self.sess.dcx().emit_fatal(errors::FailedWritingFile { path: &path, error });
-        }
+        queries.finish();
 
         ret
     }

compiler/rustc_middle/messages.ftl

@@ -73,6 +73,9 @@ middle_drop_check_overflow =
 
 middle_erroneous_constant = erroneous constant encountered
 
+middle_failed_writing_file =
+    failed to write file {$path}: {$error}"
+
 middle_layout_references_error =
     the type has an unknown layout
 

compiler/rustc_middle/src/error.rs

@@ -1,5 +1,5 @@
-use std::fmt;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
+use std::{fmt, io};
 
 use rustc_errors::codes::*;
 use rustc_errors::{DiagArgName, DiagArgValue, DiagMessage};
@@ -18,6 +18,13 @@ pub struct DropCheckOverflow<'tcx> {
     pub overflow_ty: Ty<'tcx>,
 }
 
+#[derive(Diagnostic)]
+#[diag(middle_failed_writing_file)]
+pub struct FailedWritingFile<'a> {
+    pub path: &'a Path,
+    pub error: io::Error,
+}
+
 #[derive(Diagnostic)]
 #[diag(middle_opaque_hidden_type_mismatch)]
 pub struct OpaqueHiddenTypeMismatch<'tcx> {

compiler/rustc_middle/src/hooks/mod.rs

@@ -108,6 +108,19 @@ declare_hooks! {
     /// Returns `true` if we should codegen an instance in the local crate, or returns `false` if we
     /// can just link to the upstream crate and therefore don't need a mono item.
     hook should_codegen_locally(instance: crate::ty::Instance<'tcx>) -> bool;
+
+    hook alloc_self_profile_query_strings() -> ();
+
+    /// Saves and writes the DepGraph to the file system.
+    ///
+    /// This function saves both the dep-graph and the query result cache,
+    /// and drops the result cache.
+    ///
+    /// This function should only run after all queries have completed.
+    /// Trying to execute a query afterwards would attempt to read the result cache we just dropped.
+    hook save_dep_graph() -> ();
+
+    hook query_key_hash_verify_all() -> ();
 }
 
 #[cold]

compiler/rustc_middle/src/ty/context.rs

@@ -1365,8 +1365,17 @@ impl<'tcx> GlobalCtxt<'tcx> {
         tls::enter_context(&icx, || f(icx.tcx))
     }
 
-    pub fn finish(&self) -> FileEncodeResult {
-        self.dep_graph.finish_encoding()
+    pub fn finish(&'tcx self) {
+        // We assume that no queries are run past here. If there are new queries
+        // after this point, they'll show up as "<unknown>" in self-profiling data.
+        self.enter(|tcx| tcx.alloc_self_profile_query_strings());
+
+        self.enter(|tcx| tcx.save_dep_graph());
+        self.enter(|tcx| tcx.query_key_hash_verify_all());
+
+        if let Err((path, error)) = self.dep_graph.finish_encoding() {
+            self.sess.dcx().emit_fatal(crate::error::FailedWritingFile { path: &path, error });
+        }
     }
 }
 

compiler/rustc_query_impl/src/lib.rs

@@ -222,3 +222,9 @@ pub fn query_system<'tcx>(
 }
 
 rustc_middle::rustc_query_append! { define_queries! }
+
+pub fn provide(providers: &mut rustc_middle::util::Providers) {
+    providers.hooks.alloc_self_profile_query_strings =
+        |tcx| alloc_self_profile_query_strings(tcx.tcx);
+    providers.hooks.query_key_hash_verify_all = |tcx| query_key_hash_verify_all(tcx.tcx);
+}

compiler/rustc_query_impl/src/profiling_support.rs

@@ -252,6 +252,8 @@ pub fn alloc_self_profile_query_strings(tcx: TyCtxt<'_>) {
         return;
     }
 
+    let _prof_timer = tcx.sess.prof.generic_activity("self_profile_alloc_query_strings");
+
     let mut string_cache = QueryKeyStringCache::new();
 
     for alloc in super::ALLOC_SELF_PROFILE_QUERY_STRINGS.iter() {