cold

Author: jdonszelmann

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -199,6 +199,9 @@ pub enum AttributeKind {
         span: Span,
     },
 
+    /// Represents `#[cold]`.
+    Cold(Span),
+
     /// Represents `#[rustc_confusables]`.
     Confusables {
         symbols: ThinVec<Symbol>,

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -38,3 +38,21 @@ impl<S: Stage> SingleAttributeParser<S> for OptimizeParser {
         Some(AttributeKind::Optimize(res, cx.attr_span))
     }
 }
+
+pub(crate) struct ColdParser;
+
+impl<S: Stage> SingleAttributeParser<S> for ColdParser {
+    const PATH: &[rustc_span::Symbol] = &[sym::cold];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const TEMPLATE: AttributeTemplate = template!(Word);
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if !args.no_args() {
+            cx.expected_no_args(cx.attr_span);
+            return None;
+        };
+
+        Some(AttributeKind::Cold(cx.attr_span))
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -15,7 +15,7 @@ use rustc_session::Session;
 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::codegen_attrs::{ColdParser, OptimizeParser};
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
@@ -105,6 +105,7 @@ attribute_parsers!(
 
         // tidy-alphabetical-start
         Single<AsPtrParser>,
+        Single<ColdParser>,
         Single<ConstStabilityIndirectParser>,
         Single<DeprecationParser>,
         Single<InlineParser>,
@@ -233,6 +234,16 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         })
     }
 
+    pub(crate) fn expected_no_args(&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::ExpectedNoArgs,
+        })
+    }
+
     /// emit an error that a `name = value` pair was expected at this span. The symbol can be given for
     /// a nicer error message talking about the specific name that was found lacking a value.
     pub(crate) fn expected_name_value(&self, span: Span, name: Option<Symbol>) -> ErrorGuaranteed {

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -466,6 +466,7 @@ pub(crate) struct UnrecognizedReprHint {
 }
 
 pub(crate) enum AttributeParseErrorReason {
+    ExpectedNoArgs,
     ExpectedStringLiteral { byte_string: Option<Span> },
     ExpectedSingleArgument,
     ExpectedList,
@@ -521,6 +522,10 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                 diag.span_label(self.span, format!("didn't expect a literal here"));
                 diag.code(E0565);
             }
+            AttributeParseErrorReason::ExpectedNoArgs => {
+                diag.span_label(self.span, format!("didn't expect any arguments here"));
+                diag.code(E0565);
+            }
             AttributeParseErrorReason::ExpectedNameValue(None) => {
                 diag.span_label(
                     self.span,

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -118,6 +118,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                         .filter_map(|(r, _)| if let ReprAlign(x) = r { Some(*x) } else { None })
                         .max();
                 }
+                AttributeKind::Cold(_) => codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD,
 
                 _ => {}
             }
@@ -128,7 +129,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
         };
 
         match name {
-            sym::cold => codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD,
             sym::rustc_allocator => codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR,
             sym::ffi_pure => codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_PURE,
             sym::ffi_const => codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_CONST,

compiler/rustc_passes/src/check_attr.rs

@@ -149,6 +149,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 }
                 Attribute::Parsed(AttributeKind::Repr(_)) => { /* handled below this loop and elsewhere */
                 }
+                Attribute::Parsed(AttributeKind::Cold(attr_span)) => {
+                    self.check_cold(hir_id, *attr_span, span, target)
+                }
                 Attribute::Parsed(
                     AttributeKind::BodyStability { .. }
                     | AttributeKind::ConstStabilityIndirect
@@ -241,7 +244,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         [sym::ffi_pure, ..] => self.check_ffi_pure(attr.span(), attrs, target),
                         [sym::ffi_const, ..] => self.check_ffi_const(attr.span(), target),
                         [sym::link_ordinal, ..] => self.check_link_ordinal(attr, span, target),
-                        [sym::cold, ..] => self.check_cold(hir_id, attr, span, target),
                         [sym::link, ..] => self.check_link(hir_id, attr, span, target),
                         [sym::link_name, ..] => self.check_link_name(hir_id, attr, span, target),
                         [sym::link_section, ..] => self.check_link_section(hir_id, attr, span, target),
@@ -646,8 +648,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             sym::instruction_set,
             sym::repr,
             sym::rustc_std_internal_symbol,
-            // code generation
-            sym::cold,
             // documentation
             sym::doc,
         ];
@@ -681,7 +681,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     // this check can be part of the parser and be removed here
                     match other_attr {
                         Attribute::Parsed(
-                            AttributeKind::Deprecation { .. } | AttributeKind::Repr { .. },
+                            AttributeKind::Deprecation { .. }
+                            | AttributeKind::Repr { .. }
+                            | AttributeKind::Cold(..),
                         ) => {
                             continue;
                         }
@@ -1630,23 +1632,23 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     /// Checks if `#[cold]` is applied to a non-function.
-    fn check_cold(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+    fn check_cold(&self, hir_id: HirId, attr_span: Span, span: Span, target: Target) {
         match target {
             Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => {}
             // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
             // `#[cold]` attribute with just a lint, because we previously
             // erroneously allowed it and some crates used it accidentally, to be compatible
             // with crates depending on them, we can't throw an error here.
             Target::Field | Target::Arm | Target::MacroDef => {
-                self.inline_attr_str_error_with_macro_def(hir_id, attr.span(), "cold");
+                self.inline_attr_str_error_with_macro_def(hir_id, attr_span, "cold");
             }
             _ => {
                 // FIXME: #[cold] was previously allowed on non-functions and some crates used
                 // this, so only emit a warning.
                 self.tcx.emit_node_span_lint(
                     UNUSED_ATTRIBUTES,
                     hir_id,
-                    attr.span(),
+                    attr_span,
                     errors::Cold { span, on_crate: hir_id == CRATE_HIR_ID },
                 );
             }

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.stderr

@@ -379,14 +379,6 @@ warning: `#[proc_macro_derive]` only has an effect on functions
 LL | #![proc_macro_derive()]
    | ^^^^^^^^^^^^^^^^^^^^^^^
 
-warning: attribute should be applied to a function definition
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:62:1
-   |
-LL | #![cold]
-   | ^^^^^^^^ cannot be applied to crates
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-
 warning: attribute should be applied to an `extern` block with non-Rust ABI
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:64:1
    |
@@ -417,6 +409,14 @@ warning: `#[must_use]` has no effect when applied to a module
 LL | #![must_use]
    | ^^^^^^^^^^^^
 
+warning: attribute should be applied to a function definition
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:62:1
+   |
+LL | #![cold]
+   | ^^^^^^^^ cannot be applied to crates
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+
 warning: `#[macro_use]` only has an effect on `extern crate` and modules
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:176:5
    |

tests/ui/lint/unused/unused-attr-duplicate.stderr

@@ -102,18 +102,6 @@ note: attribute also specified here
 LL | #[automatically_derived]
    | ^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:77:1
-   |
-LL | #[cold]
-   | ^^^^^^^ help: remove this attribute
-   |
-note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:76:1
-   |
-LL | #[cold]
-   | ^^^^^^^
-
 error: unused attribute
   --> $DIR/unused-attr-duplicate.rs:79:1
    |
@@ -289,5 +277,17 @@ LL | #[inline(always)]
    | ^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
+error: unused attribute
+  --> $DIR/unused-attr-duplicate.rs:77:1
+   |
+LL | #[cold]
+   | ^^^^^^^ help: remove this attribute
+   |
+note: attribute also specified here
+  --> $DIR/unused-attr-duplicate.rs:76:1
+   |
+LL | #[cold]
+   | ^^^^^^^
+
 error: aborting due to 23 previous errors