add a flag to codegen fn attrs for foreign items

2 files changed, 5 insertions, 4 deletions

diff --git a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
index 78cafe8566b..866736f74a0 100644
--- a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
+++ b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
@@ -2,7 +2,6 @@ use std::borrow::Cow;
 
 use rustc_abi::Align;
 use rustc_hir::attrs::{InlineAttr, InstructionSetAttr, Linkage, OptimizeAttr};
-use rustc_hir::def_id::DefId;
 use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 use rustc_span::Symbol;
 use rustc_target::spec::SanitizerSet;
@@ -161,6 +160,8 @@ bitflags::bitflags! {
         const ALLOCATOR_ZEROED          = 1 << 14;
         /// `#[no_builtins]`: indicates that disable implicit builtin knowledge of functions for the function.
         const NO_BUILTINS               = 1 << 15;
+        /// Marks foreign items, to make `contains_extern_indicator` cheaper.
+        const FOREIGN_ITEM              = 1 << 16;
     }
 }
 rustc_data_structures::external_bitflags_debug! { CodegenFnAttrFlags }
@@ -194,8 +195,8 @@ impl CodegenFnAttrs {
     /// * `#[linkage]` is present
     ///
     /// Keep this in sync with the logic for the unused_attributes for `#[inline]` lint.
-    pub fn contains_extern_indicator(&self, tcx: TyCtxt<'_>, did: DefId) -> bool {
-        if tcx.is_foreign_item(did) {
+    pub fn contains_extern_indicator(&self) -> bool {
+        if self.flags.contains(CodegenFnAttrFlags::FOREIGN_ITEM) {
             return false;
         }
 
diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs
index 533066bdef9..6b45b2dc3ff 100644
--- a/compiler/rustc_middle/src/mir/mono.rs
+++ b/compiler/rustc_middle/src/mir/mono.rs
@@ -149,7 +149,7 @@ impl<'tcx> MonoItem<'tcx> {
         // instantiation:
         // We emit an unused_attributes lint for this case, which should be kept in sync if possible.
         let codegen_fn_attrs = tcx.codegen_instance_attrs(instance.def);
-        if codegen_fn_attrs.contains_extern_indicator(tcx, instance.def.def_id())
+        if codegen_fn_attrs.contains_extern_indicator()
             || codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED)
         {
             return InstantiationMode::GloballyShared { may_conflict: false };