Make #[used] statics have external linkage

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

@@ -127,6 +127,8 @@ impl CodegenFnAttrs {
     /// * `#[linkage]` is present
     pub fn contains_extern_indicator(&self) -> bool {
         self.flags.contains(CodegenFnAttrFlags::NO_MANGLE)
+            || self.flags.contains(CodegenFnAttrFlags::USED)
+            || self.flags.contains(CodegenFnAttrFlags::USED_LINKER)
             || self.export_name.is_some()
             || match self.linkage {
                 // These are private, so make sure we don't try to consider

compiler/rustc_passes/src/dead.rs

@@ -11,7 +11,6 @@ use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::{Node, PatKind, TyKind};
 use rustc_middle::hir::nested_filter;
-use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::middle::privacy;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
@@ -466,10 +465,7 @@ fn has_allow_dead_code_or_lang_attr(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
 
     // #[used], #[no_mangle], #[export_name], etc also keeps the item alive
     // forcefully, e.g., for placing it in a specific section.
-    if cg_attrs.contains_extern_indicator()
-        || cg_attrs.flags.contains(CodegenFnAttrFlags::USED)
-        || cg_attrs.flags.contains(CodegenFnAttrFlags::USED_LINKER)
-    {
+    if cg_attrs.contains_extern_indicator() {
         return true;
     }
 

src/test/codegen/external-used-statics.rs

@@ -0,0 +1,78 @@
+// revisions: lib staticlib
+// ignore-emscripten default visibility is hidden
+// compile-flags: -O
+// `#[used]`d static variables always have external linkage, i.e., no `internal` in their
+// definitions
+
+#![cfg_attr(lib, crate_type = "lib")]
+#![cfg_attr(staticlib, crate_type = "staticlib")]
+
+// CHECK: @{{.*}}A{{.*}} = constant
+#[used]
+static A: u8 = 0;
+
+// CHECK: @{{.*}}B{{.*}} = global
+#[used]
+static mut B: u8 = 0;
+
+// CHECK: @{{.*}}C{{.*}} = constant
+#[used]
+pub static C: u8 = 0;
+
+// CHECK: @{{.*}}D{{.*}} = global
+#[used]
+pub static mut D: u8 = 0;
+
+mod private {
+    // CHECK: @{{.*}}E{{.*}} = constant
+    #[used]
+    static E: u8 = 0;
+
+    // CHECK: @{{.*}}F{{.*}} = global
+    #[used]
+    static mut F: u8 = 0;
+
+    // CHECK: @{{.*}}G{{.*}} = constant
+    #[used]
+    pub static G: u8 = 0;
+
+    // CHECK: @{{.*}}H{{.*}} = global
+    #[used]
+    pub static mut H: u8 = 0;
+}
+
+const HIDDEN: () = {
+    // CHECK: @{{.*}}I{{.*}} = constant
+    #[used]
+    static I: u8 = 0;
+
+    // CHECK: @{{.*}}J{{.*}} = global
+    #[used]
+    static mut J: u8 = 0;
+
+    // CHECK: @{{.*}}K{{.*}} = constant
+    #[used]
+    pub static K: u8 = 0;
+
+    // CHECK: @{{.*}}L{{.*}} = global
+    #[used]
+    pub static mut L: u8 = 0;
+};
+
+fn x() {
+    // CHECK: @{{.*}}M{{.*}} = constant
+    #[used]
+    static M: fn() = x;
+
+    // CHECK: @{{.*}}N{{.*}} = global
+    #[used]
+    static mut N: u8 = 0;
+
+    // CHECK: @{{.*}}O{{.*}} = constant
+    #[used]
+    pub static O: u8 = 0;
+
+    // CHECK: @{{.*}}P{{.*}} = global
+    #[used]
+    pub static mut P: u8 = 0;
+}