Auto merge of rust-lang#85296 - bjorn3:plugin_cleanup, r=petrochenkov

Plugin interface cleanup

The first commit performs two uncontroversial cleanups. The second commit removes `#[plugin_registrar]` and instead requires you to export a `__rustc_plugin_registrar` function, this will require a change to servo's script_plugins (cc `@jdm)`

Author: bors

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -375,14 +375,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             }
 
             ast::ItemKind::Fn(..) => {
-                if self.sess.contains_name(&i.attrs[..], sym::plugin_registrar) {
-                    gate_feature_post!(
-                        &self,
-                        plugin_registrar,
-                        i.span,
-                        "compiler plugins are experimental and possibly buggy"
-                    );
-                }
                 if self.sess.contains_name(&i.attrs[..], sym::start) {
                     gate_feature_post!(
                         &self,

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -137,10 +137,6 @@ fn reachable_non_generics_provider(tcx: TyCtxt<'_>, cnum: CrateNum) -> DefIdMap<
         reachable_non_generics.insert(id.to_def_id(), SymbolExportLevel::C);
     }
 
-    if let Some(id) = tcx.plugin_registrar_fn(()) {
-        reachable_non_generics.insert(id.to_def_id(), SymbolExportLevel::C);
-    }
-
     reachable_non_generics
 }
 

compiler/rustc_feature/src/active.rs

@@ -281,9 +281,6 @@ declare_features! (
     // feature-group-start: actual feature gates
     // -------------------------------------------------------------------------
 
-    /// Allows using `#[plugin_registrar]` on functions.
-    (active, plugin_registrar, "1.0.0", Some(29597), None),
-
     /// Allows using `#![plugin(myplugin)]`.
     (active, plugin, "1.0.0", Some(29597), None),
 

compiler/rustc_feature/src/builtin_attrs.rs

@@ -291,18 +291,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
 
     // Plugins:
-    (
-        sym::plugin_registrar, Normal, template!(Word),
-        Gated(
-            Stability::Deprecated(
-                "https://github.com/rust-lang/rust/pull/64675",
-                Some("may be removed in a future compiler version"),
-            ),
-            sym::plugin_registrar,
-            "compiler plugins are deprecated",
-            cfg_fn!(plugin_registrar)
-        )
-    ),
     (
         sym::plugin, CrateLevel, template!(List: "name"),
         Gated(

compiler/rustc_feature/src/removed.rs

@@ -136,9 +136,12 @@ declare_features! (
     (removed, main, "1.53.0", Some(29634), None, None),
     (removed, pub_macro_rules, "1.53.0", Some(78855), None,
      Some("removed due to being incomplete, in particular it does not work across crates")),
-     /// Allows the definition of `const` functions with some advanced features.
+    /// Allows the definition of `const` functions with some advanced features.
     (removed, const_fn, "1.54.0", Some(57563), None,
      Some("split into finer-grained feature gates")),
+    /// Allows using `#[plugin_registrar]` on functions.
+    (removed, plugin_registrar, "1.54.0", Some(29597), None,
+     Some("a __rustc_plugin_registrar symbol must now be defined instead")),
 
     /// Allows `#[doc(include = "some-file")]`.
     (removed, external_doc, "1.54.0", Some(44732), None,

compiler/rustc_interface/src/passes.rs

@@ -741,7 +741,6 @@ pub static DEFAULT_QUERY_PROVIDERS: SyncLazy<Providers> = SyncLazy::new(|| {
     let providers = &mut Providers::default();
     providers.analysis = analysis;
     proc_macro_decls::provide(providers);
-    plugin::build::provide(providers);
     rustc_middle::hir::provide(providers);
     mir::provide(providers);
     mir_build::provide(providers);
@@ -856,8 +855,6 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
             {
                 entry_point = sess.time("looking_for_entry_point", || tcx.entry_fn(()));
 
-                sess.time("looking_for_plugin_registrar", || tcx.ensure().plugin_registrar_fn(()));
-
                 sess.time("looking_for_derive_registrar", || {
                     tcx.ensure().proc_macro_decls_static(())
                 });

compiler/rustc_metadata/src/locator.rs

@@ -226,7 +226,7 @@ use rustc_session::config::{self, CrateType};
 use rustc_session::filesearch::{FileDoesntMatch, FileMatches, FileSearch};
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::CanonicalizedPath;
-use rustc_session::{Session, StableCrateId};
+use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use rustc_target::spec::{Target, TargetTriple};
@@ -787,7 +787,7 @@ pub fn find_plugin_registrar(
     metadata_loader: &dyn MetadataLoader,
     span: Span,
     name: Symbol,
-) -> (PathBuf, StableCrateId) {
+) -> PathBuf {
     match find_plugin_registrar_impl(sess, metadata_loader, name) {
         Ok(res) => res,
         // `core` is always available if we got as far as loading plugins.
@@ -799,7 +799,7 @@ fn find_plugin_registrar_impl<'a>(
     sess: &'a Session,
     metadata_loader: &dyn MetadataLoader,
     name: Symbol,
-) -> Result<(PathBuf, StableCrateId), CrateError> {
+) -> Result<PathBuf, CrateError> {
     info!("find plugin registrar `{}`", name);
     let mut locator = CrateLocator::new(
         sess,
@@ -816,7 +816,7 @@ fn find_plugin_registrar_impl<'a>(
 
     match locator.maybe_load_library_crate()? {
         Some(library) => match library.source.dylib {
-            Some(dylib) => Ok((dylib.0, library.metadata.get_root().stable_crate_id())),
+            Some(dylib) => Ok(dylib.0),
             None => Err(CrateError::NonDylibPlugin(name)),
         },
         None => Err(locator.into_error()),

compiler/rustc_middle/src/query/mod.rs

@@ -1252,9 +1252,6 @@ rustc_queries! {
     query entry_fn(_: ()) -> Option<(DefId, EntryFnType)> {
         desc { "looking up the entry function of a crate" }
     }
-    query plugin_registrar_fn(_: ()) -> Option<LocalDefId> {
-        desc { "looking up the plugin registrar for a crate" }
-    }
     query proc_macro_decls_static(_: ()) -> Option<LocalDefId> {
         desc { "looking up the derive registrar for a crate" }
     }

compiler/rustc_plugin_impl/src/build.rs

@@ -12,7 +12,6 @@
 
 use rustc_lint::LintStore;
 
-pub mod build;
 pub mod load;
 
 /// Structure used to register plugins.