Rollup merge of #138682 - Alexendoo:extra-symbols, r=fee1-dead

Allow drivers to supply a list of extra symbols to intern

Allows adding new symbols as `const`s in external drivers, desirable in Clippy so we can use them in patterns to replace code like https://github.com/rust-lang/rust/blob/75530e9f72a1990ed2305e16fd51d02f47048f12/src/tools/clippy/clippy_lints/src/casts/cast_ptr_alignment.rs#L66

The Clippy change adds a couple symbols as a demo, the exact `clippy_utils` API and replacing other usages can be done on the Clippy side to minimise sync conflicts

---

try-job: aarch64-gnu

3 files changed, 27 insertions, 11 deletions

diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 33b4a48b28d..708fe23b791 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -348,6 +348,10 @@ pub struct Config {
     /// the list of queries.
     pub override_queries: Option<fn(&Session, &mut Providers)>,
 
+    /// An extra set of symbols to add to the symbol interner, the symbol indices
+    /// will start at [`PREDEFINED_SYMBOLS_COUNT`](rustc_span::symbol::PREDEFINED_SYMBOLS_COUNT)
+    pub extra_symbols: Vec<&'static str>,
+
     /// This is a callback from the driver that is called to create a codegen backend.
     ///
     /// Has no uses within this repository, but is used by bjorn3 for "the
@@ -409,6 +413,7 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
         &early_dcx,
         config.opts.edition,
         config.opts.unstable_opts.threads,
+        &config.extra_symbols,
         SourceMapInputs { file_loader, path_mapping, hash_kind, checksum_hash_kind },
         |current_gcx| {
             // The previous `early_dcx` can't be reused here because it doesn't
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index a8e55663257..75a1b61b416 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -53,7 +53,7 @@ where
         checksum_hash_kind,
     });
 
-    rustc_span::create_session_globals_then(DEFAULT_EDITION, sm_inputs, || {
+    rustc_span::create_session_globals_then(DEFAULT_EDITION, &[], sm_inputs, || {
         let temps_dir = sessopts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
         let io = CompilerIO {
             input: Input::Str { name: FileName::Custom(String::new()), input: String::new() },
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index 83d80938b4e..f5d4f3fc118 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -117,6 +117,7 @@ fn run_in_thread_with_globals<F: FnOnce(CurrentGcx) -> R + Send, R: Send>(
     thread_stack_size: usize,
     edition: Edition,
     sm_inputs: SourceMapInputs,
+    extra_symbols: &[&'static str],
     f: F,
 ) -> R {
     // The "thread pool" is a single spawned thread in the non-parallel
@@ -134,9 +135,12 @@ fn run_in_thread_with_globals<F: FnOnce(CurrentGcx) -> R + Send, R: Send>(
         // name contains null bytes.
         let r = builder
             .spawn_scoped(s, move || {
-                rustc_span::create_session_globals_then(edition, Some(sm_inputs), || {
-                    f(CurrentGcx::new())
-                })
+                rustc_span::create_session_globals_then(
+                    edition,
+                    extra_symbols,
+                    Some(sm_inputs),
+                    || f(CurrentGcx::new()),
+                )
             })
             .unwrap()
             .join();
@@ -152,6 +156,7 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce(CurrentGcx) -> R + Send,
     thread_builder_diag: &EarlyDiagCtxt,
     edition: Edition,
     threads: usize,
+    extra_symbols: &[&'static str],
     sm_inputs: SourceMapInputs,
     f: F,
 ) -> R {
@@ -168,12 +173,18 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce(CurrentGcx) -> R + Send,
     let registry = sync::Registry::new(std::num::NonZero::new(threads).unwrap());
 
     if !sync::is_dyn_thread_safe() {
-        return run_in_thread_with_globals(thread_stack_size, edition, sm_inputs, |current_gcx| {
-            // Register the thread for use with the `WorkerLocal` type.
-            registry.register();
-
-            f(current_gcx)
-        });
+        return run_in_thread_with_globals(
+            thread_stack_size,
+            edition,
+            sm_inputs,
+            extra_symbols,
+            |current_gcx| {
+                // Register the thread for use with the `WorkerLocal` type.
+                registry.register();
+
+                f(current_gcx)
+            },
+        );
     }
 
     let current_gcx = FromDyn::from(CurrentGcx::new());
@@ -230,7 +241,7 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce(CurrentGcx) -> R + Send,
     // pool. Upon creation, each worker thread created gets a copy of the
     // session globals in TLS. This is possible because `SessionGlobals` impls
     // `Send` in the parallel compiler.
-    rustc_span::create_session_globals_then(edition, Some(sm_inputs), || {
+    rustc_span::create_session_globals_then(edition, extra_symbols, Some(sm_inputs), || {
         rustc_span::with_session_globals(|session_globals| {
             let session_globals = FromDyn::from(session_globals);
             builder