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`

1 files changed, 4 insertions, 3 deletions

diff --git a/src/librustc_codegen_llvm/debuginfo/gdb.rs b/src/librustc_codegen_llvm/debuginfo/gdb.rs
index 64d4076cbf0..29edd66049c 100644
--- a/src/librustc_codegen_llvm/debuginfo/gdb.rs
+++ b/src/librustc_codegen_llvm/debuginfo/gdb.rs
@@ -9,7 +9,6 @@ use rustc_codegen_ssa::traits::*;
 use rustc_middle::bug;
 use rustc_session::config::DebugInfo;
 
-use rustc_ast::attr;
 use rustc_span::symbol::sym;
 
 /// Inserts a side-effect free instruction sequence that makes sure that the
@@ -61,8 +60,10 @@ pub fn get_or_insert_gdb_debug_scripts_section_global(cx: &CodegenCx<'ll, '_>) -
 }
 
 pub fn needs_gdb_debug_scripts_section(cx: &CodegenCx<'_, '_>) -> bool {
-    let omit_gdb_pretty_printer_section =
-        attr::contains_name(&cx.tcx.hir().krate_attrs(), sym::omit_gdb_pretty_printer_section);
+    let omit_gdb_pretty_printer_section = cx
+        .tcx
+        .sess
+        .contains_name(&cx.tcx.hir().krate_attrs(), sym::omit_gdb_pretty_printer_section);
 
     !omit_gdb_pretty_printer_section
         && cx.sess().opts.debuginfo != DebugInfo::None