Port #[rustc_allocator_zeroed_variant] to attr parser

Author: Bryntet

compiler/rustc_attr_parsing/src/attributes/rustc_allocator.rs

@@ -20,6 +20,25 @@ impl<S: Stage> NoArgsAttributeParser<S> for RustcAllocatorZeroedParser {
     const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcAllocatorZeroed;
 }
 
+pub(crate) struct RustcAllocatorZeroedVariantParser;
+
+impl<S: Stage> SingleAttributeParser<S> for RustcAllocatorZeroedVariantParser {
+    const PATH: &[Symbol] = &[sym::rustc_allocator_zeroed_variant];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets =
+        AllowedTargets::AllowList(&[Allow(Target::Fn), Allow(Target::ForeignFn)]);
+    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "function");
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+        let Some(name) = args.name_value().and_then(NameValueParser::value_as_str) else {
+            cx.expected_name_value(cx.attr_span, None);
+            return None;
+        };
+
+        Some(AttributeKind::RustcAllocatorZeroedVariant { name })
+    }
+}
+
 pub(crate) struct RustcDeallocatorParser;
 
 impl<S: Stage> NoArgsAttributeParser<S> for RustcDeallocatorParser {

compiler/rustc_attr_parsing/src/context.rs

@@ -65,8 +65,8 @@ use crate::attributes::proc_macro_attrs::{
 use crate::attributes::prototype::CustomMirParser;
 use crate::attributes::repr::{AlignParser, AlignStaticParser, ReprParser};
 use crate::attributes::rustc_allocator::{
-    RustcAllocatorParser, RustcAllocatorZeroedParser, RustcDeallocatorParser,
-    RustcReallocatorParser,
+    RustcAllocatorParser, RustcAllocatorZeroedParser, RustcAllocatorZeroedVariantParser,
+    RustcDeallocatorParser, RustcReallocatorParser,
 };
 use crate::attributes::rustc_dump::{
     RustcDumpDefParents, RustcDumpItemBounds, RustcDumpPredicates, RustcDumpUserArgs,
@@ -227,6 +227,7 @@ attribute_parsers!(
         Single<PatternComplexityLimitParser>,
         Single<ProcMacroDeriveParser>,
         Single<RecursionLimitParser>,
+        Single<RustcAllocatorZeroedVariantParser>,
         Single<RustcBuiltinMacroParser>,
         Single<RustcForceInlineParser>,
         Single<RustcLayoutScalarValidRangeEndParser>,

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -1,6 +1,7 @@
 //! Set and unset common attributes on LLVM values.
 use rustc_hir::attrs::{InlineAttr, InstructionSetAttr, OptimizeAttr, RtsanSetting};
 use rustc_hir::def_id::DefId;
+use rustc_hir::find_attr;
 use rustc_middle::middle::codegen_fn_attrs::{
     CodegenFnAttrFlags, CodegenFnAttrs, PatchableFunctionEntry, SanitizerFnAttrs,
 };
@@ -470,9 +471,7 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
     {
         to_add.push(create_alloc_family_attr(cx.llcx));
         if let Some(instance) = instance
-            && let Some(zv) =
-                tcx.get_attr(instance.def_id(), rustc_span::sym::rustc_allocator_zeroed_variant)
-            && let Some(name) = zv.value_str()
+            && let Some(name) = find_attr!(tcx.get_all_attrs(instance.def_id()), rustc_hir::attrs::AttributeKind::RustcAllocatorZeroedVariant {name} => name)
         {
             to_add.push(llvm::CreateAttrStringValue(
                 cx.llcx,

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -912,6 +912,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_allocator_zeroed]`
     RustcAllocatorZeroed,
 
+    /// Represents `#[rustc_allocator_zeroed_variant]`
+    RustcAllocatorZeroedVariant { name: Symbol },
+
     /// Represents `#[rustc_builtin_macro]`.
     RustcBuiltinMacro { builtin_name: Option<Symbol>, helper_attrs: ThinVec<Symbol>, span: Span },
 

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -99,6 +99,7 @@ impl AttributeKind {
             Repr { .. } => No,
             RustcAllocator => No,
             RustcAllocatorZeroed => No,
+            RustcAllocatorZeroedVariant { .. } => Yes,
             RustcBuiltinMacro { .. } => Yes,
             RustcCoherenceIsCore(..) => No,
             RustcDeallocator => No,

compiler/rustc_passes/src/check_attr.rs

@@ -318,6 +318,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::NeedsAllocator
                     | AttributeKind::RustcAllocator
                     | AttributeKind::RustcAllocatorZeroed
+                    | AttributeKind::RustcAllocatorZeroedVariant { .. }
                     | AttributeKind::RustcDeallocator
                     | AttributeKind::RustcReallocator
                 ) => { /* do nothing  */ }
@@ -365,7 +366,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::rustc_reservation_impl
                             | sym::rustc_doc_primitive
                             | sym::rustc_conversion_suggestion
-                            | sym::rustc_allocator_zeroed_variant
                             | sym::rustc_deprecated_safe_2024
                             | sym::rustc_test_marker
                             | sym::rustc_abi