Add flag for rustc_std_internal_symbol attribute

Part of #47320

4 files changed, 9 insertions, 8 deletions

diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index e9bada5a147..69f43bc293d 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -2228,6 +2228,7 @@ bitflags! {
         const RUSTC_ALLOCATOR_NOUNWIND  = 0b0000_1000;
         const NAKED                     = 0b0001_0000;
         const NO_MANGLE                 = 0b0010_0000;
+        const RUSTC_STD_INTERNAL_SYMBOL = 0b0100_0000;
     }
 }
 
diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs
index 10c2f9f758f..20edef8b35c 100644
--- a/src/librustc_mir/monomorphize/collector.rs
+++ b/src/librustc_mir/monomorphize/collector.rs
@@ -188,7 +188,7 @@
 //! this is not implemented however: a mono item will be produced
 //! regardless of whether it is actually needed or not.
 
-use rustc::hir;
+use rustc::hir::{self, TransFnAttrFlags};
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
 
 use rustc::hir::map as hir_map;
@@ -211,8 +211,6 @@ use monomorphize::item::{MonoItemExt, DefPathBasedNames, InstantiationMode};
 
 use rustc_data_structures::bitvec::BitVector;
 
-use syntax::attr;
-
 use std::iter;
 
 #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
@@ -985,8 +983,8 @@ impl<'b, 'a, 'v> RootCollector<'b, 'a, 'v> {
             MonoItemCollectionMode::Lazy => {
                 self.entry_fn == Some(def_id) ||
                 self.tcx.is_reachable_non_generic(def_id) ||
-                attr::contains_name(&self.tcx.get_attrs(def_id),
-                                    "rustc_std_internal_symbol")
+                self.tcx.trans_fn_attrs(def_id).flags.contains(
+                    TransFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)
             }
         }
     }
diff --git a/src/librustc_trans/back/symbol_export.rs b/src/librustc_trans/back/symbol_export.rs
index 799d8319767..fd79ae7435e 100644
--- a/src/librustc_trans/back/symbol_export.rs
+++ b/src/librustc_trans/back/symbol_export.rs
@@ -13,6 +13,7 @@ use std::sync::Arc;
 
 use monomorphize::Instance;
 use rustc::hir;
+use rustc::hir::TransFnAttrFlags;
 use rustc::hir::def_id::CrateNum;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::middle::exported_symbols::{SymbolExportLevel, ExportedSymbol, metadata_symbol_name};
@@ -21,7 +22,6 @@ use rustc::ty::{TyCtxt, SymbolName};
 use rustc::ty::maps::Providers;
 use rustc::util::nodemap::{FxHashMap, DefIdSet};
 use rustc_allocator::ALLOCATOR_METHODS;
-use syntax::attr;
 
 pub type ExportedSymbols = FxHashMap<
     CrateNum,
@@ -258,8 +258,8 @@ fn symbol_export_level_provider(tcx: TyCtxt, sym_def_id: DefId) -> SymbolExportL
     // are not considered for export
     let trans_fn_attrs = tcx.trans_fn_attrs(sym_def_id);
     let is_extern = trans_fn_attrs.contains_extern_indicator();
-    let std_internal = attr::contains_name(&tcx.get_attrs(sym_def_id),
-                                           "rustc_std_internal_symbol");
+    let std_internal = trans_fn_attrs.flags.contains(TransFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL);
+
     if is_extern && !std_internal {
         SymbolExportLevel::C
     } else {
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 76d2be6695c..f8e10c208ac 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -1745,6 +1745,8 @@ fn trans_fn_attrs<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: DefId) -> TransFnAt
             trans_fn_attrs.flags |= TransFnAttrFlags::NAKED;
         } else if attr.check_name("no_mangle") {
             trans_fn_attrs.flags |= TransFnAttrFlags::NO_MANGLE;
+        } else if attr.check_name("rustc_std_internal_symbol") {
+            trans_fn_attrs.flags |= TransFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
         } else if attr.check_name("inline") {
             trans_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
                 if attr.path != "inline" {