use an allow list for allowed asm options in naked functions

Author: folkertdev

compiler/rustc_passes/src/naked_functions.rs

@@ -244,22 +244,19 @@ impl<'tcx> CheckInlineAssembly<'tcx> {
             self.tcx.dcx().emit_err(NakedFunctionsOperands { unsupported_operands });
         }
 
-        let unsupported_options: Vec<&'static str> = [
-            (InlineAsmOptions::MAY_UNWIND, "`may_unwind`"),
-            (InlineAsmOptions::NOMEM, "`nomem`"),
-            (InlineAsmOptions::NOSTACK, "`nostack`"),
-            (InlineAsmOptions::PRESERVES_FLAGS, "`preserves_flags`"),
-            (InlineAsmOptions::PURE, "`pure`"),
-            (InlineAsmOptions::READONLY, "`readonly`"),
-        ]
-        .iter()
-        .filter_map(|&(option, name)| if asm.options.contains(option) { Some(name) } else { None })
-        .collect();
+        let supported_options =
+            InlineAsmOptions::RAW | InlineAsmOptions::NORETURN | InlineAsmOptions::ATT_SYNTAX;
+        let unsupported_options = asm.options.difference(supported_options);
 
         if !unsupported_options.is_empty() {
             self.tcx.dcx().emit_err(NakedFunctionsAsmOptions {
                 span,
-                unsupported_options: unsupported_options.join(", "),
+                unsupported_options: unsupported_options
+                    .human_readable_names()
+                    .into_iter()
+                    .map(|name| format!("`{name}`"))
+                    .collect::<Vec<_>>()
+                    .join(", "),
             });
         }
 

tests/ui/asm/naked-functions.rs

@@ -111,7 +111,7 @@ unsafe extern "C" fn invalid_options() {
 unsafe extern "C" fn invalid_options_continued() {
     asm!("", options(readonly, nostack), options(pure));
     //~^ ERROR asm with the `pure` option must have at least one output
-    //~| ERROR asm options unsupported in naked functions: `nostack`, `pure`, `readonly`
+    //~| ERROR asm options unsupported in naked functions: `pure`, `readonly`, `nostack`
     //~| ERROR asm in naked functions must use `noreturn` option
 }
 

tests/ui/asm/naked-functions.stderr

@@ -212,7 +212,7 @@ error[E0787]: asm options unsupported in naked functions: `nomem`, `preserves_fl
 LL |     asm!("", options(nomem, preserves_flags, noreturn));
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0787]: asm options unsupported in naked functions: `nostack`, `pure`, `readonly`
+error[E0787]: asm options unsupported in naked functions: `pure`, `readonly`, `nostack`
   --> $DIR/naked-functions.rs:112:5
    |
 LL |     asm!("", options(readonly, nostack), options(pure));