expand: Pass ast::Crate by reference to AST transforming passes

Also some more attributes are passed by reference.

Author: petrochenkov

Diff for: compiler/rustc_builtin_macros/src/cmdline_attrs.rs

@@ -6,7 +6,7 @@ use rustc_ast::{self as ast, AttrItem, AttrStyle};
 use rustc_session::parse::ParseSess;
 use rustc_span::FileName;
 
-pub fn inject(mut krate: ast::Crate, parse_sess: &ParseSess, attrs: &[String]) -> ast::Crate {
+pub fn inject(krate: &mut ast::Crate, parse_sess: &ParseSess, attrs: &[String]) {
     for raw_attr in attrs {
         let mut parser = rustc_parse::new_parser_from_source_str(
             parse_sess,
@@ -36,6 +36,4 @@ pub fn inject(mut krate: ast::Crate, parse_sess: &ParseSess, attrs: &[String]) -
             start_span.to(end_span),
         ));
     }
-
-    krate
 }

Diff for: compiler/rustc_builtin_macros/src/proc_macro_harness.rs

@@ -43,14 +43,14 @@ struct CollectProcMacros<'a> {
 }
 
 pub fn inject(
+    krate: &mut ast::Crate,
     sess: &Session,
     resolver: &mut dyn ResolverExpand,
-    mut krate: ast::Crate,
     is_proc_macro_crate: bool,
     has_proc_macro_decls: bool,
     is_test_crate: bool,
     handler: &rustc_errors::Handler,
-) -> ast::Crate {
+) {
     let ecfg = ExpansionConfig::default("proc_macro".to_string());
     let mut cx = ExtCtxt::new(sess, ecfg, resolver, None);
 
@@ -64,22 +64,20 @@ pub fn inject(
     };
 
     if has_proc_macro_decls || is_proc_macro_crate {
-        visit::walk_crate(&mut collect, &krate);
+        visit::walk_crate(&mut collect, krate);
     }
     let macros = collect.macros;
 
     if !is_proc_macro_crate {
-        return krate;
+        return;
     }
 
     if is_test_crate {
-        return krate;
+        return;
     }
 
     let decls = mk_decls(&mut cx, &macros);
     krate.items.push(decls);
-
-    krate
 }
 
 impl<'a> CollectProcMacros<'a> {

Diff for: compiler/rustc_builtin_macros/src/standard_library_imports.rs

@@ -8,16 +8,12 @@ use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::DUMMY_SP;
 use thin_vec::thin_vec;
 
-pub fn inject(
-    mut krate: ast::Crate,
-    resolver: &mut dyn ResolverExpand,
-    sess: &Session,
-) -> ast::Crate {
+pub fn inject(krate: &mut ast::Crate, resolver: &mut dyn ResolverExpand, sess: &Session) {
     let edition = sess.parse_sess.edition;
 
     // the first name in this list is the crate name of the crate with the prelude
     let names: &[Symbol] = if attr::contains_name(&krate.attrs, sym::no_core) {
-        return krate;
+        return;
     } else if attr::contains_name(&krate.attrs, sym::no_std) {
         if attr::contains_name(&krate.attrs, sym::compiler_builtins) {
             &[sym::core]
@@ -88,6 +84,4 @@ pub fn inject(
     );
 
     krate.items.insert(0, use_item);
-
-    krate
 }

Diff for: compiler/rustc_builtin_macros/src/test_harness.rs

@@ -37,7 +37,7 @@ struct TestCtxt<'a> {
 
 /// Traverse the crate, collecting all the test functions, eliding any
 /// existing main functions, and synthesizing a main test harness
-pub fn inject(sess: &Session, resolver: &mut dyn ResolverExpand, krate: &mut ast::Crate) {
+pub fn inject(krate: &mut ast::Crate, sess: &Session, resolver: &mut dyn ResolverExpand) {
     let span_diagnostic = sess.diagnostic();
     let panic_strategy = sess.panic_strategy();
     let platform_panic_strategy = sess.target.panic_strategy;

Diff for: compiler/rustc_expand/src/config.rs

@@ -192,38 +192,32 @@ fn get_features(sess: &Session, krate_attrs: &[ast::Attribute]) -> Features {
 }
 
 /// `cfg_attr`-process the crate's attributes and compute the crate's features.
-pub fn features(
-    sess: &Session,
-    mut krate: ast::Crate,
-    lint_node_id: NodeId,
-) -> (ast::Crate, Features) {
+pub fn features(sess: &Session, krate: &mut ast::Crate, lint_node_id: NodeId) -> Features {
     let mut strip_unconfigured =
         StripUnconfigured { sess, features: None, config_tokens: false, lint_node_id };
 
-    let unconfigured_attrs = krate.attrs.clone();
+    let mut unconfigured_attrs = krate.attrs.clone();
     let diag = &sess.parse_sess.span_diagnostic;
     let err_count = diag.err_count();
-    let features = match strip_unconfigured.configure_krate_attrs(krate.attrs) {
-        None => {
-            // The entire crate is unconfigured.
-            krate.attrs = ast::AttrVec::new();
-            krate.items = ThinVec::new();
-            Features::default()
-        }
-        Some(attrs) => {
-            krate.attrs = attrs;
-            let features = get_features(sess, &krate.attrs);
-            if err_count == diag.err_count() {
-                // Avoid reconfiguring malformed `cfg_attr`s.
-                strip_unconfigured.features = Some(&features);
-                // Run configuration again, this time with features available
-                // so that we can perform feature-gating.
-                strip_unconfigured.configure_krate_attrs(unconfigured_attrs);
-            }
-            features
+
+    krate.attrs.flat_map_in_place(|attr| strip_unconfigured.process_cfg_attr(&attr));
+    if !strip_unconfigured.in_cfg(&krate.attrs) {
+        // The entire crate is unconfigured.
+        krate.attrs = ast::AttrVec::new();
+        krate.items = ThinVec::new();
+        Features::default()
+    } else {
+        let features = get_features(sess, &krate.attrs);
+        if err_count == diag.err_count() {
+            // Avoid reconfiguring malformed `cfg_attr`s.
+            strip_unconfigured.features = Some(&features);
+            // Run configuration again, this time with features available
+            // so that we can perform feature-gating.
+            unconfigured_attrs.flat_map_in_place(|attr| strip_unconfigured.process_cfg_attr(&attr));
+            strip_unconfigured.in_cfg(&unconfigured_attrs);
         }
-    };
-    (krate, features)
+        features
+    }
 }
 
 #[macro_export]
@@ -254,11 +248,6 @@ impl<'a> StripUnconfigured<'a> {
         }
     }
 
-    fn configure_krate_attrs(&self, mut attrs: ast::AttrVec) -> Option<ast::AttrVec> {
-        attrs.flat_map_in_place(|attr| self.process_cfg_attr(attr));
-        self.in_cfg(&attrs).then_some(attrs)
-    }
-
     /// Performs cfg-expansion on `stream`, producing a new `AttrTokenStream`.
     /// This is only used during the invocation of `derive` proc-macros,
     /// which require that we cfg-expand their entire input.
@@ -281,7 +270,7 @@ impl<'a> StripUnconfigured<'a> {
             .iter()
             .flat_map(|tree| match tree.clone() {
                 AttrTokenTree::Attributes(mut data) => {
-                    data.attrs.flat_map_in_place(|attr| self.process_cfg_attr(attr));
+                    data.attrs.flat_map_in_place(|attr| self.process_cfg_attr(&attr));
 
                     if self.in_cfg(&data.attrs) {
                         data.tokens = LazyAttrTokenStream::new(
@@ -319,12 +308,16 @@ impl<'a> StripUnconfigured<'a> {
     /// the syntax of any `cfg_attr` is incorrect.
     fn process_cfg_attrs<T: HasAttrs>(&self, node: &mut T) {
         node.visit_attrs(|attrs| {
-            attrs.flat_map_in_place(|attr| self.process_cfg_attr(attr));
+            attrs.flat_map_in_place(|attr| self.process_cfg_attr(&attr));
         });
     }
 
-    fn process_cfg_attr(&self, attr: Attribute) -> Vec<Attribute> {
-        if attr.has_name(sym::cfg_attr) { self.expand_cfg_attr(attr, true) } else { vec![attr] }
+    fn process_cfg_attr(&self, attr: &Attribute) -> Vec<Attribute> {
+        if attr.has_name(sym::cfg_attr) {
+            self.expand_cfg_attr(attr, true)
+        } else {
+            vec![attr.clone()]
+        }
     }
 
     /// Parse and expand a single `cfg_attr` attribute into a list of attributes
@@ -334,9 +327,9 @@ impl<'a> StripUnconfigured<'a> {
     /// Gives a compiler warning when the `cfg_attr` contains no attributes and
     /// is in the original source file. Gives a compiler error if the syntax of
     /// the attribute is incorrect.
-    pub(crate) fn expand_cfg_attr(&self, attr: Attribute, recursive: bool) -> Vec<Attribute> {
+    pub(crate) fn expand_cfg_attr(&self, attr: &Attribute, recursive: bool) -> Vec<Attribute> {
         let Some((cfg_predicate, expanded_attrs)) =
-            rustc_parse::parse_cfg_attr(&attr, &self.sess.parse_sess) else {
+            rustc_parse::parse_cfg_attr(attr, &self.sess.parse_sess) else {
                 return vec![];
             };
 
@@ -365,10 +358,10 @@ impl<'a> StripUnconfigured<'a> {
             //  `#[cfg_attr(false, cfg_attr(true, some_attr))]`.
             expanded_attrs
                 .into_iter()
-                .flat_map(|item| self.process_cfg_attr(self.expand_cfg_attr_item(&attr, item)))
+                .flat_map(|item| self.process_cfg_attr(&self.expand_cfg_attr_item(attr, item)))
                 .collect()
         } else {
-            expanded_attrs.into_iter().map(|item| self.expand_cfg_attr_item(&attr, item)).collect()
+            expanded_attrs.into_iter().map(|item| self.expand_cfg_attr_item(attr, item)).collect()
         }
     }
 

Diff for: compiler/rustc_expand/src/expand.rs

@@ -1688,7 +1688,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
         res
     }
 
-    fn expand_cfg_attr(&self, node: &mut impl HasAttrs, attr: ast::Attribute, pos: usize) {
+    fn expand_cfg_attr(&self, node: &mut impl HasAttrs, attr: &ast::Attribute, pos: usize) {
         node.visit_attrs(|attrs| {
             // Repeated `insert` calls is inefficient, but the number of
             // insertions is almost always 0 or 1 in practice.
@@ -1712,7 +1712,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
                         Default::default()
                     }
                     sym::cfg_attr => {
-                        self.expand_cfg_attr(&mut node, attr, pos);
+                        self.expand_cfg_attr(&mut node, &attr, pos);
                         continue;
                     }
                     _ => {
@@ -1760,7 +1760,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
                         continue;
                     }
                     sym::cfg_attr => {
-                        self.expand_cfg_attr(node, attr, pos);
+                        self.expand_cfg_attr(node, &attr, pos);
                         continue;
                     }
                     _ => visit_clobber(node, |node| {

Diff for: compiler/rustc_interface/src/passes.rs

@@ -76,18 +76,18 @@ pub fn register_plugins<'a>(
     sess: &'a Session,
     metadata_loader: &'a dyn MetadataLoader,
     register_lints: impl Fn(&Session, &mut LintStore),
-    mut krate: ast::Crate,
+    krate: &mut ast::Crate,
     crate_name: Symbol,
-) -> Result<(ast::Crate, LintStore)> {
-    krate = sess.time("attributes_injection", || {
+) -> Result<LintStore> {
+    sess.time("attributes_injection", || {
         rustc_builtin_macros::cmdline_attrs::inject(
             krate,
             &sess.parse_sess,
             &sess.opts.unstable_opts.crate_attr,
         )
     });
 
-    let (krate, features) = rustc_expand::config::features(sess, krate, CRATE_NODE_ID);
+    let features = rustc_expand::config::features(sess, krate, CRATE_NODE_ID);
     // these need to be set "early" so that expansion sees `quote` if enabled.
     sess.init_features(features);
 
@@ -117,16 +117,16 @@ pub fn register_plugins<'a>(
     let mut lint_store = rustc_lint::new_lint_store(sess.enable_internal_lints());
     register_lints(sess, &mut lint_store);
 
-    let registrars =
-        sess.time("plugin_loading", || plugin::load::load_plugins(sess, metadata_loader, &krate));
+    let registrars = sess
+        .time("plugin_loading", || plugin::load::load_plugins(sess, metadata_loader, &krate.attrs));
     sess.time("plugin_registration", || {
         let mut registry = plugin::Registry { lint_store: &mut lint_store };
         for registrar in registrars {
             registrar(&mut registry);
         }
     });
 
-    Ok((krate, lint_store))
+    Ok(lint_store)
 }
 
 fn pre_expansion_lint<'a>(
@@ -181,8 +181,8 @@ fn configure_and_expand(mut krate: ast::Crate, resolver: &mut Resolver<'_, '_>)
     pre_expansion_lint(sess, lint_store, tcx.registered_tools(()), &krate, crate_name);
     rustc_builtin_macros::register_builtin_macros(resolver);
 
-    krate = sess.time("crate_injection", || {
-        rustc_builtin_macros::standard_library_imports::inject(krate, resolver, sess)
+    sess.time("crate_injection", || {
+        rustc_builtin_macros::standard_library_imports::inject(&mut krate, resolver, sess)
     });
 
     util::check_attr_crate_type(sess, &krate.attrs, &mut resolver.lint_buffer());
@@ -263,7 +263,7 @@ fn configure_and_expand(mut krate: ast::Crate, resolver: &mut Resolver<'_, '_>)
     });
 
     sess.time("maybe_building_test_harness", || {
-        rustc_builtin_macros::test_harness::inject(sess, resolver, &mut krate)
+        rustc_builtin_macros::test_harness::inject(&mut krate, sess, resolver)
     });
 
     let has_proc_macro_decls = sess.time("AST_validation", || {
@@ -287,12 +287,12 @@ fn configure_and_expand(mut krate: ast::Crate, resolver: &mut Resolver<'_, '_>)
         sess.emit_warning(errors::ProcMacroCratePanicAbort);
     }
 
-    krate = sess.time("maybe_create_a_macro_crate", || {
+    sess.time("maybe_create_a_macro_crate", || {
         let is_test_crate = sess.opts.test;
         rustc_builtin_macros::proc_macro_harness::inject(
+            &mut krate,
             sess,
             resolver,
-            krate,
             is_proc_macro_crate,
             has_proc_macro_decls,
             is_test_crate,

Diff for: compiler/rustc_interface/src/queries.rs

@@ -136,14 +136,14 @@ impl<'tcx> Queries<'tcx> {
     pub fn register_plugins(&self) -> Result<QueryResult<'_, (ast::Crate, Lrc<LintStore>)>> {
         self.register_plugins.compute(|| {
             let crate_name = *self.crate_name()?.borrow();
-            let krate = self.parse()?.steal();
+            let mut krate = self.parse()?.steal();
 
             let empty: &(dyn Fn(&Session, &mut LintStore) + Sync + Send) = &|_, _| {};
-            let (krate, lint_store) = passes::register_plugins(
+            let lint_store = passes::register_plugins(
                 self.session(),
                 &*self.codegen_backend().metadata_loader(),
                 self.compiler.register_lints.as_deref().unwrap_or_else(|| empty),
-                krate,
+                &mut krate,
                 crate_name,
             )?;
 

Diff for: compiler/rustc_plugin_impl/src/load.rs

@@ -3,7 +3,7 @@
 use crate::errors::{LoadPluginError, MalformedPluginAttribute};
 use crate::Registry;
 use libloading::Library;
-use rustc_ast::Crate;
+use rustc_ast::Attribute;
 use rustc_metadata::locator;
 use rustc_session::cstore::MetadataLoader;
 use rustc_session::Session;
@@ -20,11 +20,11 @@ type PluginRegistrarFn = fn(&mut Registry<'_>);
 pub fn load_plugins(
     sess: &Session,
     metadata_loader: &dyn MetadataLoader,
-    krate: &Crate,
+    attrs: &[Attribute],
 ) -> Vec<PluginRegistrarFn> {
     let mut plugins = Vec::new();
 
-    for attr in &krate.attrs {
+    for attr in attrs {
         if !attr.has_name(sym::plugin) {
             continue;
         }