Add error for invalid item of instruction_set

Author: chansuke

compiler/rustc_passes/messages.ftl

@@ -104,6 +104,10 @@ 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

compiler/rustc_passes/src/check_attr.rs

@@ -4,11 +4,9 @@
 //! conflicts between multiple such attributes attached to the same
 //! item.
 
-use std::cell::Cell;
-use std::collections::hash_map::Entry;
-
 use rustc_ast::{
-    ast, AttrKind, AttrStyle, Attribute, LitKind, MetaItemKind, MetaItemLit, NestedMetaItem,
+    ast, token::TokenKind, tokenstream::TokenTree, AttrKind, AttrStyle, Attribute, LitKind,
+    MetaItemKind, MetaItemLit, NestedMetaItem,
 };
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{Applicability, DiagCtxtHandle, IntoDiagArg, MultiSpan, StashKey};
@@ -38,6 +36,8 @@ 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};
@@ -243,6 +243,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 [sym::coroutine, ..] => {
                     self.check_coroutine(attr, target);
                 }
+                [sym::instruction_set, ..] => {
+                    self.check_instruction_set(attr, item);
+                }
                 [
                     // ok
                     sym::allow
@@ -260,7 +263,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | sym::omit_gdb_pretty_printer_section // FIXME(omit_gdb_pretty_printer_section)
                     | sym::used // handled elsewhere to restrict to static items
                     | sym::repr // handled elsewhere to restrict to type decls items
-                    | sym::instruction_set // broken on stable!!!
                     | sym::windows_subsystem // broken on stable!!!
                     | sym::patchable_function_entry // FIXME(patchable_function_entry)
                     | sym::deprecated_safe // FIXME(deprecated_safe)
@@ -2349,6 +2351,38 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             }
         }
     }
+
+    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();
+            let mut tokens = inner_tokens.trees();
+
+            // Valid item for `instruction_set()` is:
+            // - arm::a32
+            // - arm::t32
+            let valid_attribute = match (tokens.next(), tokens.next(), tokens.next()) {
+                (
+                    Some(TokenTree::Token(first_token, _)),
+                    Some(TokenTree::Token(second_token, _)),
+                    Some(TokenTree::Token(third_token, _)),
+                ) => match (first_token.ident(), second_token.kind.clone(), third_token.ident()) {
+                    (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
+                    }
+                    _ => false,
+                },
+                _ => false,
+            };
+
+            if !valid_attribute {
+                self.dcx().emit_err(errors::InvalidInstructionSet { span: attr.span });
+            } else {
+                return;
+            }
+        }
+    }
 }
 
 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {

compiler/rustc_passes/src/errors.rs

@@ -643,6 +643,13 @@ pub struct CoroutineOnNonClosure {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_invalid_instruction_set)]
+pub struct InvalidInstructionSet {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_empty_confusables)]
 pub(crate) struct EmptyConfusables {

tests/ui/attributes/instruction-set.rs

@@ -0,0 +1,21 @@
+#![feature(stmt_expr_attributes)]
+
+#[instruction_set(arm::a32)]
+type ValidA = ();
+
+#[instruction_set(arm::t32)]
+type ValidB = ();
+
+#[instruction_set(asdfasdf)] //~ ERROR `[instruction_set]` attribute argument should be valid
+type InvalidA = ();
+
+#[instruction_set(asdfasdf)] //~ ERROR `[instruction_set]` attribute argument should be valid
+mod InvalidB {}
+
+#[instruction_set(asdfasdf)] //~ ERROR `[instruction_set]` attribute argument should be valid
+struct InvalidC;
+
+#[instruction_set(asdfasdf)] //~ ERROR `[instruction_set]` attribute argument should be valid
+impl InvalidC {}
+
+fn main() {}

tests/ui/attributes/instruction-set.stderr

@@ -0,0 +1,26 @@
+error: `[instruction_set]` attribute argument should be valid
+  --> $DIR/instruction-set.rs:9:1
+   |
+LL | #[instruction_set(asdfasdf)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `[instruction_set]` attribute argument should be valid
+  --> $DIR/instruction-set.rs:12:1
+   |
+LL | #[instruction_set(asdfasdf)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `[instruction_set]` attribute argument should be valid
+  --> $DIR/instruction-set.rs:15:1
+   |
+LL | #[instruction_set(asdfasdf)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `[instruction_set]` attribute argument should be valid
+  --> $DIR/instruction-set.rs:18:1
+   |
+LL | #[instruction_set(asdfasdf)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
+