Update exisgting instruction_set error handling

Author: chansuke

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -397,38 +397,20 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                                         unreachable!()
                                     }
                                 }
-                                _ => {
-                                    struct_span_code_err!(
-                                        tcx.dcx(),
-                                        attr.span,
-                                        E0779,
-                                        "invalid instruction set specified",
-                                    )
-                                    .emit();
-                                    None
-                                }
+                                _ => None,
+                                // _ => {
+                                //     struct_span_code_err!(
+                                //         tcx.dcx(),
+                                //         attr.span,
+                                //         E0779,
+                                //         "invalid instruction set specified",
+                                //     )
+                                //     .emit();
+                                //     None
+                                // }
                             }
                         }
-                        [] => {
-                            struct_span_code_err!(
-                                tcx.dcx(),
-                                attr.span,
-                                E0778,
-                                "`#[instruction_set]` requires an argument"
-                            )
-                            .emit();
-                            None
-                        }
-                        _ => {
-                            struct_span_code_err!(
-                                tcx.dcx(),
-                                attr.span,
-                                E0779,
-                                "cannot specify more than one instruction set"
-                            )
-                            .emit();
-                            None
-                        }
+                        _ => None,
                     })
             }
             sym::repr => {

compiler/rustc_passes/messages.ftl

@@ -108,6 +108,10 @@ passes_invalid_instruction_set =
     `[instruction_set]` attribute argument should be valid
     .label = `[instruction_set]` containes invalid argument
 
+passes_empty_instruction_set =
+    `[instruction_set]` requires an argument
+    .label = `[instruction_set]` requires an argument
+
 passes_coverage_not_fn_or_closure =
     attribute should be applied to a function definition or closure
     .label = not a function or closure

compiler/rustc_passes/src/check_attr.rs

@@ -2352,6 +2352,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
+    // TODO: empty
     fn check_instruction_set(&self, attr: &Attribute, _item: Option<ItemLike<'_>>) {
         if let AttrKind::Normal(ref p) = attr.kind {
             let inner_tokens = p.item.args.inner_tokens();
@@ -2360,7 +2361,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             // Valid item for `instruction_set()` is:
             // - arm::a32
             // - arm::t32
-            let valid_attribute = match (tokens.next(), tokens.next(), tokens.next()) {
+            match (tokens.next(), tokens.next(), tokens.next()) {
                 (
                     Some(TokenTree::Token(first_token, _)),
                     Some(TokenTree::Token(second_token, _)),
@@ -2369,18 +2370,23 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     (Some(first_ident), TokenKind::PathSep, Some(third_ident))
                         if first_ident.0.name == sym::arm =>
                     {
-                        third_ident.0.name == sym::a32 || third_ident.0.name == sym::t32
+                        if third_ident.0.name == sym::a32 || third_ident.0.name == sym::t32 {
+                            return;
+                        } else {
+                            self.dcx().emit_err(errors::InvalidInstructionSet { span: attr.span });
+                        }
+                    }
+                    _ => {
+                        self.dcx().emit_err(errors::InvalidInstructionSet { span: attr.span });
                     }
-                    _ => false,
                 },
-                _ => false,
+                (None, None, None) => {
+                    self.dcx().emit_err(errors::EmptyInstructionSet { span: attr.span });
+                }
+                _ => {
+                    self.dcx().emit_err(errors::InvalidInstructionSet { span: attr.span });
+                }
             };
-
-            if !valid_attribute {
-                self.dcx().emit_err(errors::InvalidInstructionSet { span: attr.span });
-            } else {
-                return;
-            }
         }
     }
 }

compiler/rustc_passes/src/errors.rs

@@ -650,6 +650,13 @@ pub struct InvalidInstructionSet {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_empty_instruction_set)]
+pub struct EmptyInstructionSet {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_empty_confusables)]
 pub(crate) struct EmptyConfusables {

tests/ui/error-codes/E0778.stderr

@@ -1,9 +1,8 @@
-error[E0778]: `#[instruction_set]` requires an argument
+error: `[instruction_set]` requires an argument
   --> $DIR/E0778.rs:1:1
    |
 LL | #[instruction_set()]
    | ^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0778`.

tests/ui/error-codes/E0779.stderr

@@ -1,9 +1,8 @@
-error[E0779]: invalid instruction set specified
+error: `[instruction_set]` attribute argument should be valid
   --> $DIR/E0779.rs:1:1
    |
 LL | #[instruction_set(arm::magic)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0779`.