Update exisgting instruction_set error handling

Author: chansuke

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -380,38 +380,10 @@ 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,
-                                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

@@ -112,10 +112,6 @@ passes_coroutine_on_non_closure =
     attribute should be applied to closures
     .label = not a closure
 
-passes_invalid_instruction_set =
-    `[instruction_set]` attribute argument should be valid
-    .label = `[instruction_set]` containes invalid argument
-
 passes_coverage_not_fn_or_closure =
     attribute should be applied to a function definition or closure
     .label = not a function or closure
@@ -315,6 +311,10 @@ passes_duplicate_lang_item_crate_depends =
 passes_empty_confusables =
     expected at least one confusable name
 
+passes_empty_instruction_set =
+    `[instruction_set]` requires an argument
+    .label = `[instruction_set]` requires an argument
+
 passes_export_name =
     attribute should be applied to a free function, impl method or static
     .label = not a free function, impl method or static
@@ -404,6 +404,10 @@ passes_invalid_attr_at_crate_level =
 passes_invalid_attr_at_crate_level_item =
     the inner attribute doesn't annotate this {$kind}
 
+passes_invalid_instruction_set =
+    `[instruction_set]` attribute argument should be valid
+    .label = `[instruction_set]` containes invalid argument
+
 passes_invalid_macro_export_arguments = `{$name}` isn't a valid `#[macro_export]` argument
 
 passes_invalid_macro_export_arguments_too_many_items = `#[macro_export]` can only take 1 or 0 arguments

compiler/rustc_passes/src/check_attr.rs

@@ -4,6 +4,11 @@
 //! conflicts between multiple such attributes attached to the same
 //! item.
 
+use std::cell::Cell;
+use std::collections::hash_map::Entry;
+
+use rustc_ast::token::TokenKind;
+use rustc_ast::tokenstream::TokenTree;
 use rustc_ast::{
     AttrKind, AttrStyle, Attribute, LitKind, MetaItemInner, MetaItemKind, MetaItemLit, ast,
     token::TokenKind, tokenstream::TokenTree, AttrKind, AttrStyle, Attribute, LitKind,
@@ -38,8 +43,6 @@ use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::infer::{TyCtxtInferExt, ValuePairs};
 use rustc_trait_selection::traits::ObligationCtxt;
-use std::cell::Cell;
-use std::collections::hash_map::Entry;
 use tracing::debug;
 
 use crate::{errors, fluent_generated as fluent};
@@ -2412,7 +2415,7 @@ 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, _)),
@@ -2421,18 +2424,23 @@ 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

@@ -703,6 +703,13 @@ 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`.