Make #[naked] an unsafe attribute

compiler/rustc_builtin_macros/messages.ftl

@@ -247,9 +247,9 @@ builtin_macros_multiple_defaults = multiple declared defaults
     .suggestion = make `{$ident}` default
 
 builtin_macros_naked_functions_testing_attribute =
-    cannot use `#[naked]` with testing attributes
+    cannot use `#[unsafe(naked)]` with testing attributes
     .label = function marked with testing attribute here
-    .naked_attribute = `#[naked]` is incompatible with testing attributes
+    .naked_attribute = `#[unsafe(naked)]` is incompatible with testing attributes
 
 builtin_macros_no_default_variant = `#[derive(Default)]` on enum with no `#[default]`
     .label = this enum needs a unit variant marked with `#[default]`

compiler/rustc_codegen_cranelift/example/mini_core_hello_world.rs

@@ -387,11 +387,9 @@ global_asm! {
 }
 
 #[cfg(all(not(jit), target_arch = "x86_64"))]
-#[naked]
+#[unsafe(naked)]
 extern "C" fn naked_test() {
-    unsafe {
-        naked_asm!("ret");
-    }
+    naked_asm!("ret")
 }
 
 #[repr(C)]

compiler/rustc_error_codes/src/error_codes/E0736.md

@@ -11,7 +11,7 @@ Erroneous code example:
 
 ```compile_fail,E0736
 #[inline]
-#[naked]
+#[unsafe(naked)]
 fn foo() {}
 ```
 

compiler/rustc_error_codes/src/error_codes/E0787.md

@@ -5,7 +5,7 @@ Erroneous code example:
 ```compile_fail,E0787
 #![feature(naked_functions)]
 
-#[naked]
+#[unsafe(naked)]
 pub extern "C" fn f() -> u32 {
     42
 }

compiler/rustc_feature/src/builtin_attrs.rs

@@ -517,7 +517,7 @@ pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
 
     // Linking:
     gated!(
-        naked, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
+        unsafe naked, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
         naked_functions, experimental!(naked)
     ),
 

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -564,13 +564,17 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
                 }
             }
             ExprKind::InlineAsm(box InlineAsmExpr {
-                asm_macro: AsmMacro::Asm | AsmMacro::NakedAsm,
+                asm_macro: asm_macro @ (AsmMacro::Asm | AsmMacro::NakedAsm),
                 ref operands,
                 template: _,
                 options: _,
                 line_spans: _,
             }) => {
-                self.requires_unsafe(expr.span, UseOfInlineAssembly);
+                // The `naked` attribute and the `naked_asm!` block form one atomic unit of
+                // unsafety, and `naked_asm!` does not itself need to be wrapped in an unsafe block.
+                if let AsmMacro::Asm = asm_macro {
+                    self.requires_unsafe(expr.span, UseOfInlineAssembly);
+                }
 
                 // For inline asm, do not use `walk_expr`, since we want to handle the label block
                 // specially.

compiler/rustc_parse/src/validate_attr.rs

@@ -194,12 +194,6 @@ pub fn check_attribute_safety(psess: &ParseSess, safety: AttributeSafety, attr:
             }
         }
     } else if let Safety::Unsafe(unsafe_span) = attr_item.unsafety {
-        // Allow (but don't require) `#[unsafe(naked)]` so that compiler-builtins can upgrade to it.
-        // FIXME(#139797): remove this special case when compiler-builtins has upgraded.
-        if attr.has_name(sym::naked) {
-            return;
-        }
-
         psess.dcx().emit_err(errors::InvalidAttrUnsafe {
             span: unsafe_span,
             name: attr_item.path.clone(),

compiler/rustc_passes/messages.ftl

@@ -508,7 +508,7 @@ passes_must_use_no_effect =
     `#[must_use]` has no effect when applied to {$article} {$target}
 
 passes_naked_asm_outside_naked_fn =
-    the `naked_asm!` macro can only be used in functions marked with `#[naked]`
+    the `naked_asm!` macro can only be used in functions marked with `#[unsafe(naked)]`
 
 passes_naked_functions_asm_block =
     naked functions must contain a single `naked_asm!` invocation
@@ -516,9 +516,9 @@ passes_naked_functions_asm_block =
     .label_non_asm = not allowed in naked functions
 
 passes_naked_functions_incompatible_attribute =
-    attribute incompatible with `#[naked]`
-    .label = the `{$attr}` attribute is incompatible with `#[naked]`
-    .naked_attribute = function marked with `#[naked]` here
+    attribute incompatible with `#[unsafe(naked)]`
+    .label = the `{$attr}` attribute is incompatible with `#[unsafe(naked)]`
+    .naked_attribute = function marked with `#[unsafe(naked)]` here
 
 passes_naked_functions_must_naked_asm =
     the `asm!` macro is not allowed in naked functions