3 files changed, 39 insertions, 0 deletions
diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
index dc0776c5dad..214c6d70960 100644
--- a/compiler/rustc_passes/messages.ftl
+++ b/compiler/rustc_passes/messages.ftl
@@ -648,6 +648,10 @@ passes_rustc_lint_opt_ty =
     `#[rustc_lint_opt_ty]` should be applied to a struct
     .label = not a struct
 
+passes_rustc_safe_intrinsic =
+    attribute should be applied to intrinsic functions
+    .label = not an intrinsic function
+
 passes_rustc_std_internal_symbol =
     attribute should be applied to functions or statics
     .label = not a function or static
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 12118a0268b..0296215c8f9 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -195,6 +195,9 @@ impl CheckAttrVisitor<'_> {
                 | sym::rustc_promotable => self.check_stability_promotable(&attr, span, target),
                 sym::link_ordinal => self.check_link_ordinal(&attr, span, target),
                 sym::rustc_confusables => self.check_confusables(&attr, target),
+                sym::rustc_safe_intrinsic => {
+                    self.check_rustc_safe_intrinsic(hir_id, attr, span, target)
+                }
                 _ => true,
             };
 
@@ -2042,6 +2045,29 @@ impl CheckAttrVisitor<'_> {
         }
     }
 
+    fn check_rustc_safe_intrinsic(
+        &self,
+        hir_id: HirId,
+        attr: &Attribute,
+        span: Span,
+        target: Target,
+    ) -> bool {
+        let hir = self.tcx.hir();
+
+        if let Target::ForeignFn = target
+            && let Some(parent) = hir.opt_parent_id(hir_id)
+            && let hir::Node::Item(Item {
+                kind: ItemKind::ForeignMod { abi: Abi::RustIntrinsic | Abi::PlatformIntrinsic, .. },
+                ..
+            }) = hir.get(parent)
+        {
+            return true;
+        }
+
+        self.tcx.sess.emit_err(errors::RustcSafeIntrinsic { attr_span: attr.span, span });
+        false
+    }
+
     fn check_rustc_std_internal_symbol(
         &self,
         attr: &Attribute,
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 2ec6a0b9241..bcf5abbfe7d 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -621,6 +621,15 @@ pub struct RustcAllowConstFnUnstable {
 }
 
 #[derive(Diagnostic)]
+#[diag(passes_rustc_safe_intrinsic)]
+pub struct RustcSafeIntrinsic {
+    #[primary_span]
+    pub attr_span: Span,
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
 #[diag(passes_rustc_std_internal_symbol)]
 pub struct RustcStdInternalSymbol {
     #[primary_span]