convert the optimize attribute to a new parser

Author: jdonszelmann

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -38,7 +38,8 @@ pub enum InstructionSetAttr {
     ArmT32,
 }
 
-#[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq, HashStable_Generic, Default)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Default, PrintAttribute)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
 pub enum OptimizeAttr {
     /// No `#[optimize(..)]` attribute
     #[default]
@@ -191,6 +192,7 @@ pub enum AttributeKind {
     },
     Inline(InlineAttr, Span),
     MacroTransparency(Transparency),
+    Optimize(OptimizeAttr, Span),
     Repr(ThinVec<(ReprAttr, Span)>),
     RustcForceInline(Span, Option<Symbol>),
     Stability {

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -0,0 +1,40 @@
+use rustc_attr_data_structures::{AttributeKind, OptimizeAttr};
+use rustc_feature::{AttributeTemplate, template};
+use rustc_span::sym;
+
+use super::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::context::{AcceptContext, Stage};
+use crate::parser::ArgParser;
+
+pub(crate) struct OptimizeParser;
+
+impl<S: Stage> SingleAttributeParser<S> for OptimizeParser {
+    const PATH: &[rustc_span::Symbol] = &[sym::optimize];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
+    const TEMPLATE: AttributeTemplate = template!(List: "size|speed|none");
+
+    fn convert(cx: &AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let Some(list) = args.list() else {
+            cx.expected_list(cx.attr_span);
+            return None;
+        };
+
+        let Some(single) = list.single() else {
+            cx.expected_single_argument(list.span);
+            return None;
+        };
+
+        let res = match single.meta_item().and_then(|i| i.word_without_args().map(|i| i.name)) {
+            Some(sym::size) => OptimizeAttr::Size,
+            Some(sym::speed) => OptimizeAttr::Speed,
+            Some(sym::none) => OptimizeAttr::DoNotOptimize,
+            _ => {
+                cx.expected_specific_argument(single.span(), vec!["size", "speed", "none"]);
+                OptimizeAttr::Default
+            }
+        };
+
+        Some(AttributeKind::Optimize(res, cx.attr_span))
+    }
+}

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -28,6 +28,7 @@ use crate::session_diagnostics::{self, UnusedMultiple};
 
 pub(crate) mod allow_unstable;
 pub(crate) mod cfg;
+pub(crate) mod codegen_attrs;
 pub(crate) mod confusables;
 pub(crate) mod deprecation;
 pub(crate) mod inline;

compiler/rustc_attr_parsing/src/context.rs

@@ -17,6 +17,7 @@ use rustc_span::symbol::kw;
 use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Symbol, sym};
 
 use crate::attributes::allow_unstable::{AllowConstFnUnstableParser, AllowInternalUnstableParser};
+use crate::attributes::codegen_attrs::OptimizeParser;
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
@@ -107,6 +108,7 @@ attribute_groups!(
         Single<ConstStabilityIndirectParser>,
         Single<DeprecationParser>,
         Single<InlineParser>,
+        Single<OptimizeParser>,
         Single<RustcForceInlineParser>,
         Single<TransparencyParser>,
         // tidy-alphabetical-end

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -533,34 +533,8 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
         codegen_fn_attrs.inline = InlineAttr::Never;
     }
 
-    codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::Default, |ia, attr| {
-        if !attr.has_name(sym::optimize) {
-            return ia;
-        }
-        let err = |sp, s| struct_span_code_err!(tcx.dcx(), sp, E0722, "{}", s).emit();
-        if attr.is_word() {
-            err(attr.span(), "expected one argument");
-            return ia;
-        }
-        let Some(ref items) = attr.meta_item_list() else {
-            return OptimizeAttr::Default;
-        };
-
-        let [item] = &items[..] else {
-            err(attr.span(), "expected one argument");
-            return OptimizeAttr::Default;
-        };
-        if item.has_name(sym::size) {
-            OptimizeAttr::Size
-        } else if item.has_name(sym::speed) {
-            OptimizeAttr::Speed
-        } else if item.has_name(sym::none) {
-            OptimizeAttr::DoNotOptimize
-        } else {
-            err(item.span(), "invalid argument");
-            OptimizeAttr::Default
-        }
-    });
+    codegen_fn_attrs.optimize =
+        find_attr!(attrs, AttributeKind::Optimize(i, _) => *i).unwrap_or(OptimizeAttr::Default);
 
     // #73631: closures inherit `#[target_feature]` annotations
     //

compiler/rustc_error_codes/src/error_codes/E0722.md

@@ -1,8 +1,14 @@
+#### Note: this error code is no longer emitted by the compiler
+
+This is because it was too specific to the `optimize` attribute.
+Similar diagnostics occur for other attributes too.
+The example here will now emit `E0539`
+
 The `optimize` attribute was malformed.
 
 Erroneous code example:
 
-```compile_fail,E0722
+```compile_fail,E0539
 #![feature(optimize_attribute)]
 
 #[optimize(something)] // error: invalid argument

compiler/rustc_error_codes/src/lib.rs

@@ -685,6 +685,7 @@ E0804: 0804,
 //  E0707, // multiple elided lifetimes used in arguments of `async fn`
 //  E0709, // multiple different lifetimes used in arguments of `async fn`
 //  E0721, // `await` keyword
+//  E0722, // replaced with a generic attribute input check
 //  E0723, // unstable feature in `const` context
 //  E0738, // Removed; errored on `#[track_caller] fn`s in `extern "Rust" { ... }`.
 //  E0744, // merged into E0728

compiler/rustc_parse/src/validate_attr.rs

@@ -243,6 +243,7 @@ fn emit_malformed_attribute(
             | sym::rustc_confusables
             | sym::repr
             | sym::deprecated
+            | sym::optimize
     ) {
         return;
     }

compiler/rustc_passes/src/check_attr.rs

@@ -128,6 +128,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 Attribute::Parsed(AttributeKind::Inline(_, attr_span)) => {
                     self.check_inline(hir_id, *attr_span, span, target)
                 }
+                Attribute::Parsed(AttributeKind::Optimize(_, attr_span)) => {
+                    self.check_optimize(hir_id, *attr_span, span, target)
+                }
                 Attribute::Parsed(AttributeKind::AllowInternalUnstable(syms)) => self
                     .check_allow_internal_unstable(
                         hir_id,
@@ -145,7 +148,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             self.check_diagnostic_on_unimplemented(attr.span(), hir_id, target)
                         }
                         [sym::coverage, ..] => self.check_coverage(attr, span, target),
-                        [sym::optimize, ..] => self.check_optimize(hir_id, attr, span, target),
                         [sym::no_sanitize, ..] => {
                             self.check_no_sanitize(attr, span, target)
                         }
@@ -485,7 +487,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
 
     /// Checks that `#[optimize(..)]` is applied to a function/closure/method,
     /// or to an impl block or module.
-    fn check_optimize(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+    fn check_optimize(&self, hir_id: HirId, attr_span: Span, span: Span, target: Target) {
         let is_valid = matches!(
             target,
             Target::Fn
@@ -494,7 +496,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         );
         if !is_valid {
             self.dcx().emit_err(errors::OptimizeInvalidTarget {
-                attr_span: attr.span(),
+                attr_span,
                 defn_span: span,
                 on_crate: hir_id == CRATE_HIR_ID,
             });

tests/ui/feature-gates/feature-gate-optimize_attribute.rs

@@ -11,5 +11,5 @@ fn none() {}
 
 #[optimize(banana)]
 //~^ ERROR the `#[optimize]` attribute is an experimental feature
-//~| ERROR E0722
+//~| ERROR malformed `optimize` attribute input [E0539]
 fn not_known() {}