Add `rustc_interface::interface::Config::parse_sess_created`

compiler/rustc_driver/src/lib.rs

@@ -215,6 +215,7 @@ fn run_compiler(
             diagnostic_output,
             stderr: None,
             lint_caps: Default::default(),
+            parse_sess_created: None,
             register_lints: None,
             override_queries: None,
             make_codegen_backend: make_codegen_backend.take().unwrap(),
@@ -298,6 +299,7 @@ fn run_compiler(
         diagnostic_output,
         stderr: None,
         lint_caps: Default::default(),
+        parse_sess_created: None,
         register_lints: None,
         override_queries: None,
         make_codegen_backend: make_codegen_backend.unwrap(),

compiler/rustc_interface/src/interface.rs

@@ -142,6 +142,9 @@ pub struct Config {
 
     pub lint_caps: FxHashMap<lint::LintId, lint::Level>,
 
+    /// This is a callback from the driver that is called when [`ParseSess`] is created.
+    pub parse_sess_created: Option<Box<dyn FnOnce(&mut ParseSess) + Send>>,
+
     /// This is a callback from the driver that is called when we're registering lints;
     /// it is called during plugin registration when we have the LintStore in a non-shared state.
     ///
@@ -166,7 +169,7 @@ pub struct Config {
 
 pub fn create_compiler_and_run<R>(config: Config, f: impl FnOnce(&Compiler) -> R) -> R {
     let registry = &config.registry;
-    let (sess, codegen_backend) = util::create_session(
+    let (mut sess, codegen_backend) = util::create_session(
         config.opts,
         config.crate_cfg,
         config.diagnostic_output,
@@ -177,6 +180,10 @@ pub fn create_compiler_and_run<R>(config: Config, f: impl FnOnce(&Compiler) -> R
         registry.clone(),
     );
 
+    if let Some(parse_sess_created) = config.parse_sess_created {
+        parse_sess_created(&mut Lrc::get_mut(&mut sess).unwrap().parse_sess);
+    }
+
     let compiler = Compiler {
         sess,
         codegen_backend,

src/librustdoc/core.rs

@@ -311,6 +311,7 @@ impl<'tcx> DocContext<'tcx> {
         diagnostic_output: DiagnosticOutput::Default,
         stderr: None,
         lint_caps,
+        parse_sess_created: None,
         register_lints: Some(box crate::lint::register_lints),
         override_queries: Some(|_sess, providers, _external_providers| {
             // Most lints will require typechecking, so just don't run them.

src/librustdoc/doctest.rs

@@ -95,6 +95,7 @@
         diagnostic_output: DiagnosticOutput::Default,
         stderr: None,
         lint_caps,
+        parse_sess_created: None,
         register_lints: Some(box crate::lint::register_lints),
         override_queries: None,
         make_codegen_backend: None,