Auto merge of #142921 - JonathanBrouwer:rustc_attributes_parser, r=oli-obk

Port `#[rustc_layout_scalar_valid_range_start/end]` to the new attrib…

Ports `rustc_layout_scalar_valid_range_start` and `rustc_layout_scalar_valid_range_end` to the new attribute parsing infrastructure for https://github.com/rust-lang/rust/issues/131229#issuecomment-2971353197

r? `@jdonszelmann`

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -36,6 +36,7 @@ pub(crate) mod lint_helpers;
 pub(crate) mod loop_match;
 pub(crate) mod must_use;
 pub(crate) mod repr;
+pub(crate) mod rustc_internal;
 pub(crate) mod semantics;
 pub(crate) mod stability;
 pub(crate) mod traits;

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -0,0 +1,59 @@
+use rustc_ast::LitKind;
+use rustc_attr_data_structures::AttributeKind;
+use rustc_feature::{AttributeTemplate, template};
+use rustc_span::{Symbol, sym};
+
+use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::context::{AcceptContext, Stage};
+use crate::parser::ArgParser;
+
+pub(crate) struct RustcLayoutScalarValidRangeStart;
+
+impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeStart {
+    const PATH: &'static [Symbol] = &[sym::rustc_layout_scalar_valid_range_start];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const TEMPLATE: AttributeTemplate = template!(List: "start");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        parse_rustc_layout_scalar_valid_range(cx, args)
+            .map(|n| AttributeKind::RustcLayoutScalarValidRangeStart(n, cx.attr_span))
+    }
+}
+
+pub(crate) struct RustcLayoutScalarValidRangeEnd;
+
+impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeEnd {
+    const PATH: &'static [Symbol] = &[sym::rustc_layout_scalar_valid_range_end];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const TEMPLATE: AttributeTemplate = template!(List: "end");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        parse_rustc_layout_scalar_valid_range(cx, args)
+            .map(|n| AttributeKind::RustcLayoutScalarValidRangeEnd(n, cx.attr_span))
+    }
+}
+
+fn parse_rustc_layout_scalar_valid_range<S: Stage>(
+    cx: &mut AcceptContext<'_, '_, S>,
+    args: &ArgParser<'_>,
+) -> Option<Box<u128>> {
+    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 Some(lit) = single.lit() else {
+        cx.expected_integer_literal(single.span());
+        return None;
+    };
+    let LitKind::Int(num, _ty) = lit.kind else {
+        cx.expected_integer_literal(single.span());
+        return None;
+    };
+    Some(Box::new(num.0))
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -27,6 +27,9 @@ use crate::attributes::lint_helpers::{AsPtrParser, PubTransparentParser};
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
 use crate::attributes::must_use::MustUseParser;
 use crate::attributes::repr::{AlignParser, ReprParser};
+use crate::attributes::rustc_internal::{
+    RustcLayoutScalarValidRangeEnd, RustcLayoutScalarValidRangeStart,
+};
 use crate::attributes::semantics::MayDangleParser;
 use crate::attributes::stability::{
     BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
@@ -131,6 +134,8 @@ attribute_parsers!(
         Single<OptimizeParser>,
         Single<PubTransparentParser>,
         Single<RustcForceInlineParser>,
+        Single<RustcLayoutScalarValidRangeEnd>,
+        Single<RustcLayoutScalarValidRangeStart>,
         Single<SkipDuringMethodDispatchParser>,
         Single<TrackCallerParser>,
         Single<TransparencyParser>,
@@ -274,6 +279,16 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         })
     }
 
+    pub(crate) fn expected_integer_literal(&self, span: Span) -> ErrorGuaranteed {
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            attribute: self.attr_path.clone(),
+            reason: AttributeParseErrorReason::ExpectedIntegerLiteral,
+        })
+    }
+
     pub(crate) fn expected_list(&self, span: Span) -> ErrorGuaranteed {
         self.emit_err(AttributeParseError {
             span,

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -510,6 +510,7 @@ pub(crate) struct NakedFunctionIncompatibleAttribute {
 pub(crate) enum AttributeParseErrorReason {
     ExpectedNoArgs,
     ExpectedStringLiteral { byte_string: Option<Span> },
+    ExpectedIntegerLiteral,
     ExpectedAtLeastOneArgument,
     ExpectedSingleArgument,
     ExpectedList,
@@ -550,6 +551,9 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                     diag.span_label(self.span, "expected a string literal here");
                 }
             }
+            AttributeParseErrorReason::ExpectedIntegerLiteral => {
+                diag.span_label(self.span, "expected an integer literal here");
+            }
             AttributeParseErrorReason::ExpectedSingleArgument => {
                 diag.span_label(self.span, "expected a single argument here");
                 diag.code(E0805);