Port #[export_stable] to the new attribute system

Author: GrigorenkoPV

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -250,6 +250,9 @@ pub enum AttributeKind {
         span: Span,
     },
 
+    /// Represents `#[export_stable]`.
+    ExportStable,
+
     /// Represents `#[inline]` and `#[rustc_force_inline]`.
     Inline(InlineAttr, Span),
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -26,6 +26,7 @@ impl AttributeKind {
             Deprecation { .. } => Yes,
             DocComment { .. } => Yes,
             ExportName { .. } => Yes,
+            ExportStable => No,
             Inline(..) => No,
             LinkName { .. } => Yes,
             LinkSection { .. } => No,

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -1,9 +1,11 @@
 use rustc_attr_data_structures::AttributeKind;
 use rustc_attr_data_structures::AttributeKind::{LinkName, LinkSection};
 use rustc_feature::{AttributeTemplate, template};
-use rustc_span::{Symbol, sym};
+use rustc_span::{Span, Symbol, sym};
 
-use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::attributes::{
+    AttributeOrder, NoArgsAttributeParser, OnDuplicate, SingleAttributeParser,
+};
 use crate::context::{AcceptContext, Stage};
 use crate::parser::ArgParser;
 use crate::session_diagnostics::NullOnLinkSection;
@@ -57,3 +59,10 @@ impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
         Some(LinkSection { name, span: cx.attr_span })
     }
 }
+
+pub(crate) struct ExportStableParser;
+impl<S: Stage> NoArgsAttributeParser<S> for ExportStableParser {
+    const PATH: &[Symbol] = &[sym::export_stable];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::ExportStable;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -22,7 +22,7 @@ use crate::attributes::codegen_attrs::{
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
-use crate::attributes::link_attrs::{LinkNameParser, LinkSectionParser};
+use crate::attributes::link_attrs::{ExportStableParser, LinkNameParser, LinkSectionParser};
 use crate::attributes::lint_helpers::{AsPtrParser, PassByValueParser, PubTransparentParser};
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
 use crate::attributes::must_use::MustUseParser;
@@ -140,6 +140,7 @@ attribute_parsers!(
         Single<WithoutArgs<ColdParser>>,
         Single<WithoutArgs<ConstContinueParser>>,
         Single<WithoutArgs<ConstStabilityIndirectParser>>,
+        Single<WithoutArgs<ExportStableParser>>,
         Single<WithoutArgs<LoopMatchParser>>,
         Single<WithoutArgs<MayDangleParser>>,
         Single<WithoutArgs<NoImplicitPreludeParser>>,

compiler/rustc_parse/src/validate_attr.rs

@@ -286,6 +286,7 @@ fn emit_malformed_attribute(
     if matches!(
         name,
         sym::inline
+            | sym::export_stable
             | sym::may_dangle
             | sym::rustc_as_ptr
             | sym::rustc_pub_transparent

compiler/rustc_passes/src/check_attr.rs

@@ -198,6 +198,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     AttributeKind::RustcLayoutScalarValidRangeStart(_num, attr_span)
                     | AttributeKind::RustcLayoutScalarValidRangeEnd(_num, attr_span),
                 ) => self.check_rustc_layout_scalar_valid_range(*attr_span, span, target),
+                Attribute::Parsed(AttributeKind::ExportStable) => {
+                    // handled in `check_export`
+                }
                 Attribute::Parsed(
                     AttributeKind::BodyStability { .. }
                     | AttributeKind::ConstStabilityIndirect
@@ -338,7 +341,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::cfg_attr
                             | sym::cfg_trace
                             | sym::cfg_attr_trace
-                            | sym::export_stable // handled in `check_export`
                             // need to be fixed
                             | sym::cfi_encoding // FIXME(cfi_encoding)
                             | sym::pointee // FIXME(derive_coerce_pointee)

compiler/rustc_passes/src/check_export.rs

@@ -2,6 +2,7 @@ use std::iter;
 use std::ops::ControlFlow;
 
 use rustc_abi::ExternAbi;
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
@@ -14,7 +15,7 @@ use rustc_middle::ty::{
     self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, Visibility,
 };
 use rustc_session::config::CrateType;
-use rustc_span::{Span, sym};
+use rustc_span::Span;
 
 use crate::errors::UnexportableItem;
 
@@ -44,7 +45,7 @@ impl<'tcx> ExportableItemCollector<'tcx> {
     }
 
     fn item_is_exportable(&self, def_id: LocalDefId) -> bool {
-        let has_attr = self.tcx.has_attr(def_id, sym::export_stable);
+        let has_attr = find_attr!(self.tcx.get_all_attrs(def_id), AttributeKind::ExportStable);
         if !self.in_exportable_mod && !has_attr {
             return false;
         }
@@ -80,7 +81,7 @@ impl<'tcx> ExportableItemCollector<'tcx> {
     fn walk_item_with_mod(&mut self, item: &'tcx hir::Item<'tcx>) {
         let def_id = item.hir_id().owner.def_id;
         let old_exportable_mod = self.in_exportable_mod;
-        if self.tcx.get_attr(def_id, sym::export_stable).is_some() {
+        if find_attr!(self.tcx.get_all_attrs(def_id), AttributeKind::ExportStable) {
             self.in_exportable_mod = true;
         }
         let old_seen_exportable_in_mod = std::mem::replace(&mut self.seen_exportable_in_mod, false);

tests/ui/attributes/malformed-attrs.stderr

@@ -40,12 +40,6 @@ error: malformed `crate_name` attribute input
 LL | #[crate_name]
    | ^^^^^^^^^^^^^ help: must be of the form: `#[crate_name = "name"]`
 
-error: malformed `export_stable` attribute input
-  --> $DIR/malformed-attrs.rs:80:1
-   |
-LL | #[export_stable = 1]
-   | ^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[export_stable]`
-
 error: malformed `coverage` attribute input
   --> $DIR/malformed-attrs.rs:89:1
    |
@@ -496,6 +490,15 @@ LL | #[target_feature]
    | expected this to be a list
    | help: must be of the form: `#[target_feature(enable = "feat1, feat2")]`
 
+error[E0565]: malformed `export_stable` attribute input
+  --> $DIR/malformed-attrs.rs:80:1
+   |
+LL | #[export_stable = 1]
+   | ^^^^^^^^^^^^^^^^---^
+   | |               |
+   | |               didn't expect any arguments here
+   | help: must be of the form: `#[export_stable]`
+
 error[E0539]: malformed `link_name` attribute input
   --> $DIR/malformed-attrs.rs:85:1
    |