Move lint_store from GlobalCtxt to Session.

This was made possible by the removal of plugin support, which
simplified lint store creation.

This simplifies the places in rustc and rustdoc that call
`describe_lints`, which are early on. The lint store is now built before
those places, so they don't have to create their own lint store for
temporary use, they can just use the main one.

Author: nnethercote

compiler/rustc_driver_impl/src/lib.rs

@@ -33,7 +33,7 @@ use rustc_feature::find_gated_cfg;
 use rustc_fluent_macro::fluent_messages;
 use rustc_interface::util::{self, collect_crate_types, get_codegen_backend};
 use rustc_interface::{interface, Queries};
-use rustc_lint::{unerased_lint_store, LintStore};
+use rustc_lint::unerased_lint_store;
 use rustc_metadata::locator;
 use rustc_session::config::{nightly_options, CG_OPTIONS, Z_OPTIONS};
 use rustc_session::config::{ErrorOutputType, Input, OutFileName, OutputType, TrimmedDefPaths};
@@ -355,16 +355,7 @@ fn run_compiler(
                     let handler = EarlyErrorHandler::new(sopts.error_format);
 
                     if sopts.describe_lints {
-                        let mut lint_store =
-                            rustc_lint::new_lint_store(compiler.session().enable_internal_lints());
-                        let registered_lints =
-                            if let Some(register_lints) = compiler.register_lints() {
-                                register_lints(compiler.session(), &mut lint_store);
-                                true
-                            } else {
-                                false
-                            };
-                        describe_lints(compiler.session(), &lint_store, registered_lints);
+                        describe_lints(compiler.session());
                         return;
                     }
                     let should_stop = print_crate_info(
@@ -437,9 +428,7 @@ fn run_compiler(
             }
 
             if sess.opts.describe_lints {
-                queries
-                    .global_ctxt()?
-                    .enter(|tcx| describe_lints(sess, unerased_lint_store(tcx), true));
+                describe_lints(sess);
                 return early_exit();
             }
 
@@ -991,7 +980,7 @@ the command line flag directly.
 }
 
 /// Write to stdout lint command options, together with a list of all available lints
-pub fn describe_lints(sess: &Session, lint_store: &LintStore, loaded_lints: bool) {
+pub fn describe_lints(sess: &Session) {
     safe_println!(
         "
 Available lint options:
@@ -1017,6 +1006,7 @@ Available lint options:
         lints
     }
 
+    let lint_store = unerased_lint_store(sess);
     let (loaded, builtin): (Vec<_>, _) =
         lint_store.get_lints().iter().cloned().partition(|&lint| lint.is_loaded);
     let loaded = sort_lints(sess, loaded);
@@ -1094,7 +1084,7 @@ Available lint options:
 
     print_lint_groups(builtin_groups, true);
 
-    match (loaded_lints, loaded.len(), loaded_groups.len()) {
+    match (sess.registered_lints, loaded.len(), loaded_groups.len()) {
         (false, 0, _) | (false, _, 0) => {
             safe_println!("Lint tools like Clippy can load additional lints and lint groups.");
         }

compiler/rustc_interface/src/interface.rs

@@ -452,6 +452,15 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
                 config.expanded_args,
             );
 
+            // Even though the session holds the lint store, we can't build the
+            // lint store until the session exists. So do that now.
+            let mut lint_store = rustc_lint::new_lint_store(sess.enable_internal_lints());
+            if let Some(register_lints) = config.register_lints.as_deref() {
+                register_lints(&sess, &mut lint_store);
+                sess.registered_lints = true;
+            }
+            sess.lint_store = Some(Lrc::new(lint_store));
+
             codegen_backend.init(&sess);
 
             let cfg = parse_cfg(&handler, config.crate_cfg);

compiler/rustc_interface/src/passes.rs

@@ -127,7 +127,7 @@ fn configure_and_expand(
     let tcx = resolver.tcx();
     let sess = tcx.sess;
     let features = tcx.features();
-    let lint_store = unerased_lint_store(tcx);
+    let lint_store = unerased_lint_store(&tcx.sess);
     let crate_name = tcx.crate_name(LOCAL_CRATE);
     let lint_check_node = (&krate, pre_configured_attrs);
     pre_expansion_lint(
@@ -319,7 +319,7 @@ fn early_lint_checks(tcx: TyCtxt<'_>, (): ()) {
         }
     });
 
-    let lint_store = unerased_lint_store(tcx);
+    let lint_store = unerased_lint_store(&tcx.sess);
     rustc_lint::check_ast_node(
         sess,
         tcx.features(),
@@ -634,7 +634,6 @@ pub fn create_global_ctxt<'tcx>(
     compiler: &'tcx Compiler,
     crate_types: Vec<CrateType>,
     stable_crate_id: StableCrateId,
-    lint_store: Lrc<LintStore>,
     dep_graph: DepGraph,
     untracked: Untracked,
     gcx_cell: &'tcx OnceLock<GlobalCtxt<'tcx>>,
@@ -665,7 +664,6 @@ pub fn create_global_ctxt<'tcx>(
                 sess,
                 crate_types,
                 stable_crate_id,
-                lint_store,
                 arena,
                 hir_arena,
                 untracked,

compiler/rustc_interface/src/queries.rs

@@ -148,12 +148,6 @@ impl<'tcx> Queries<'tcx> {
             );
             let dep_graph = setup_dep_graph(sess, crate_name, stable_crate_id)?;
 
-            let mut lint_store = rustc_lint::new_lint_store(sess.enable_internal_lints());
-            if let Some(register_lints) = self.compiler.register_lints.as_deref() {
-                register_lints(sess, &mut lint_store);
-            }
-            let lint_store = Lrc::new(lint_store);
-
             let cstore = FreezeLock::new(Box::new(CStore::new(
                 self.codegen_backend().metadata_loader(),
                 stable_crate_id,
@@ -168,7 +162,6 @@ impl<'tcx> Queries<'tcx> {
                 self.compiler,
                 crate_types,
                 stable_crate_id,
-                lint_store,
                 dep_graph,
                 untracked,
                 &self.gcx_cell,

compiler/rustc_lint/src/late.rs

@@ -17,22 +17,25 @@
 use crate::{passes::LateLintPassObject, LateContext, LateLintPass, LintStore};
 use rustc_ast as ast;
 use rustc_data_structures::stack::ensure_sufficient_stack;
-use rustc_data_structures::sync::join;
+use rustc_data_structures::sync::{join, Lrc};
 use rustc_hir as hir;
 use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_hir::intravisit as hir_visit;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::lint::LintPass;
+use rustc_session::Session;
 use rustc_span::Span;
 
 use std::any::Any;
 use std::cell::Cell;
 
 /// Extract the `LintStore` from the query context.
 /// This function exists because we've erased `LintStore` as `dyn Any` in the context.
-pub fn unerased_lint_store(tcx: TyCtxt<'_>) -> &LintStore {
-    let store: &dyn Any = &*tcx.lint_store;
+pub fn unerased_lint_store(sess: &Session) -> &LintStore {
+    assert!(sess.lint_store.is_some());
+    let store: &Lrc<_> = sess.lint_store.as_ref().unwrap();
+    let store: &dyn Any = &**store;
     store.downcast_ref().unwrap()
 }
 
@@ -361,8 +364,11 @@ pub fn late_lint_mod<'tcx, T: LateLintPass<'tcx> + 'tcx>(
     // Note: `passes` is often empty. In that case, it's faster to run
     // `builtin_lints` directly rather than bundling it up into the
     // `RuntimeCombinedLateLintPass`.
-    let mut passes: Vec<_> =
-        unerased_lint_store(tcx).late_module_passes.iter().map(|mk_pass| (mk_pass)(tcx)).collect();
+    let mut passes: Vec<_> = unerased_lint_store(&tcx.sess)
+        .late_module_passes
+        .iter()
+        .map(|mk_pass| (mk_pass)(tcx))
+        .collect();
     if passes.is_empty() {
         late_lint_mod_inner(tcx, module_def_id, context, builtin_lints);
     } else {
@@ -399,7 +405,7 @@ fn late_lint_mod_inner<'tcx, T: LateLintPass<'tcx>>(
 fn late_lint_crate<'tcx>(tcx: TyCtxt<'tcx>) {
     // Note: `passes` is often empty.
     let mut passes: Vec<_> =
-        unerased_lint_store(tcx).late_passes.iter().map(|mk_pass| (mk_pass)(tcx)).collect();
+        unerased_lint_store(&tcx.sess).late_passes.iter().map(|mk_pass| (mk_pass)(tcx)).collect();
 
     if passes.is_empty() {
         return;

compiler/rustc_lint/src/levels.rs

@@ -123,7 +123,7 @@ impl LintLevelSets {
 }
 
 fn lint_expectations(tcx: TyCtxt<'_>, (): ()) -> Vec<(LintExpectationId, LintExpectation)> {
-    let store = unerased_lint_store(tcx);
+    let store = unerased_lint_store(&tcx.sess);
 
     let mut builder = LintLevelsBuilder {
         sess: tcx.sess,
@@ -152,7 +152,7 @@ fn lint_expectations(tcx: TyCtxt<'_>, (): ()) -> Vec<(LintExpectationId, LintExp
 
 #[instrument(level = "trace", skip(tcx), ret)]
 fn shallow_lint_levels_on(tcx: TyCtxt<'_>, owner: hir::OwnerId) -> ShallowLintLevelMap {
-    let store = unerased_lint_store(tcx);
+    let store = unerased_lint_store(&tcx.sess);
     let attrs = tcx.hir_attrs(owner);
 
     let mut levels = LintLevelsBuilder {

compiler/rustc_middle/src/ty/context.rs

@@ -39,7 +39,7 @@ use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::sharded::{IntoPointer, ShardedHashMap};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::steal::Steal;
-use rustc_data_structures::sync::{self, FreezeReadGuard, Lock, Lrc, WorkerLocal};
+use rustc_data_structures::sync::{FreezeReadGuard, Lock, WorkerLocal};
 use rustc_data_structures::unord::UnordSet;
 use rustc_errors::{
     DecorateLint, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, MultiSpan,
@@ -69,7 +69,6 @@ use rustc_type_ir::TyKind::*;
 use rustc_type_ir::WithCachedTypeInfo;
 use rustc_type_ir::{CollectAndApply, Interner, TypeFlags};
 
-use std::any::Any;
 use std::borrow::Borrow;
 use std::cmp::Ordering;
 use std::fmt;
@@ -544,12 +543,6 @@ pub struct GlobalCtxt<'tcx> {
     /// `rustc_symbol_mangling` crate for more information.
     stable_crate_id: StableCrateId,
 
-    /// This only ever stores a `LintStore` but we don't want a dependency on that type here.
-    ///
-    /// FIXME(Centril): consider `dyn LintStoreMarker` once
-    /// we can upcast to `Any` for some additional type safety.
-    pub lint_store: Lrc<dyn Any + sync::DynSync + sync::DynSend>,
-
     pub dep_graph: DepGraph,
 
     pub prof: SelfProfilerRef,
@@ -709,7 +702,6 @@ impl<'tcx> TyCtxt<'tcx> {
         s: &'tcx Session,
         crate_types: Vec<CrateType>,
         stable_crate_id: StableCrateId,
-        lint_store: Lrc<dyn Any + sync::DynSend + sync::DynSync>,
         arena: &'tcx WorkerLocal<Arena<'tcx>>,
         hir_arena: &'tcx WorkerLocal<hir::Arena<'tcx>>,
         untracked: Untracked,
@@ -730,7 +722,6 @@ impl<'tcx> TyCtxt<'tcx> {
             sess: s,
             crate_types,
             stable_crate_id,
-            lint_store,
             arena,
             hir_arena,
             interners,

compiler/rustc_session/src/session.rs

@@ -17,7 +17,7 @@ use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
 use rustc_data_structures::jobserver::{self, Client};
 use rustc_data_structures::profiling::{duration_to_secs_str, SelfProfiler, SelfProfilerRef};
 use rustc_data_structures::sync::{
-    AtomicU64, AtomicUsize, Lock, Lrc, OneThread, Ordering, Ordering::SeqCst,
+    AtomicU64, AtomicUsize, DynSend, DynSync, Lock, Lrc, OneThread, Ordering, Ordering::SeqCst,
 };
 use rustc_errors::annotate_snippet_emitter_writer::AnnotateSnippetEmitterWriter;
 use rustc_errors::emitter::{DynEmitter, EmitterWriter, HumanReadableErrorType};
@@ -39,6 +39,7 @@ use rustc_target::spec::{
     DebuginfoKind, SanitizerSet, SplitDebuginfo, StackProtector, Target, TargetTriple, TlsModel,
 };
 
+use std::any::Any;
 use std::cell::{self, RefCell};
 use std::env;
 use std::fmt;
@@ -173,6 +174,15 @@ pub struct Session {
     /// false positives about a job server in our environment.
     pub jobserver: Client,
 
+    /// This only ever stores a `LintStore` but we don't want a dependency on that type here.
+    ///
+    /// FIXME(Centril): consider `dyn LintStoreMarker` once
+    /// we can upcast to `Any` for some additional type safety.
+    pub lint_store: Option<Lrc<dyn Any + DynSync + DynSend>>,
+
+    /// Should be set if any lints are registered in `lint_store`.
+    pub registered_lints: bool,
+
     /// Cap lint level specified by a driver specifically.
     pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
 
@@ -1525,6 +1535,8 @@ pub fn build_session(
         optimization_fuel,
         print_fuel,
         jobserver: jobserver::client(),
+        lint_store: None,
+        registered_lints: false,
         driver_lint_caps,
         ctfe_backtrace,
         miri_unleashed_features: Lock::new(Default::default()),

src/librustdoc/lib.rs

@@ -796,14 +796,7 @@ fn main_args(
         let sess = compiler.session();
 
         if sess.opts.describe_lints {
-            let mut lint_store = rustc_lint::new_lint_store(sess.enable_internal_lints());
-            let registered_lints = if let Some(register_lints) = compiler.register_lints() {
-                register_lints(sess, &mut lint_store);
-                true
-            } else {
-                false
-            };
-            rustc_driver::describe_lints(sess, &lint_store, registered_lints);
+            rustc_driver::describe_lints(sess);
             return Ok(());
         }