Eliminate the `SessionGlobals` from `librustc_ast`.

By moving `{known,used}_attrs` from `SessionGlobals` to `Session`. This
means they are accessed via the `Session`, rather than via TLS. A few
`Attr` methods and `librustc_ast` functions are now methods of
`Session`.

All of this required passing a `Session` to lots of functions that didn't
already have one. Some of these functions also had arguments removed, because
those arguments could be accessed directly via the `Session` argument.

`contains_feature_attr()` was dead, and is removed.

Some functions were moved from `librustc_ast` elsewhere because they now need
to access `Session`, which isn't available in that crate.
- `entry_point_type()` --> `librustc_builtin_macros`
- `global_allocator_spans()` --> `librustc_metadata`
- `is_proc_macro_attr()` --> `Session`

2 files changed, 6 insertions, 6 deletions

diff --git a/src/librustc_plugin_impl/build.rs b/src/librustc_plugin_impl/build.rs
index db2363316cd..d16dd701a12 100644
--- a/src/librustc_plugin_impl/build.rs
+++ b/src/librustc_plugin_impl/build.rs
@@ -1,6 +1,5 @@
 //! Used by `rustc` when compiling a plugin crate.
 
-use rustc_ast::attr;
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
@@ -9,14 +8,15 @@ use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
-struct RegistrarFinder {
+struct RegistrarFinder<'tcx> {
+    tcx: TyCtxt<'tcx>,
     registrars: Vec<(hir::HirId, Span)>,
 }
 
-impl<'v> ItemLikeVisitor<'v> for RegistrarFinder {
+impl<'v, 'tcx> ItemLikeVisitor<'v> for RegistrarFinder<'tcx> {
     fn visit_item(&mut self, item: &hir::Item<'_>) {
         if let hir::ItemKind::Fn(..) = item.kind {
-            if attr::contains_name(&item.attrs, sym::plugin_registrar) {
+            if self.tcx.sess.contains_name(&item.attrs, sym::plugin_registrar) {
                 self.registrars.push((item.hir_id, item.span));
             }
         }
@@ -35,7 +35,7 @@ pub fn find_plugin_registrar(tcx: TyCtxt<'_>) -> Option<DefId> {
 fn plugin_registrar_fn(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<DefId> {
     assert_eq!(cnum, LOCAL_CRATE);
 
-    let mut finder = RegistrarFinder { registrars: Vec::new() };
+    let mut finder = RegistrarFinder { tcx, registrars: Vec::new() };
     tcx.hir().krate().visit_all_item_likes(&mut finder);
 
     match finder.registrars.len() {
diff --git a/src/librustc_plugin_impl/load.rs b/src/librustc_plugin_impl/load.rs
index 62a87b47a2f..2f307302db0 100644
--- a/src/librustc_plugin_impl/load.rs
+++ b/src/librustc_plugin_impl/load.rs
@@ -32,7 +32,7 @@ pub fn load_plugins(
     let mut plugins = Vec::new();
 
     for attr in &krate.attrs {
-        if !attr.check_name(sym::plugin) {
+        if !sess.check_name(attr, sym::plugin) {
             continue;
         }