Port #[link_ordinal] to the new attribute parsing infrastructure

Author: Periodic1911

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -261,6 +261,9 @@ pub enum AttributeKind {
     /// Represents `#[link_name]`.
     LinkName { name: Symbol, span: Span },
 
+    /// Represents `#[link_ordinal]`.
+    LinkOrdinal { ordinal: u16, span: Span },
+
     /// Represents [`#[link_section]`](https://doc.rust-lang.org/reference/abi.html#the-link_section-attribute)
     LinkSection { name: Symbol, span: Span },
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -29,6 +29,7 @@ impl AttributeKind {
             Ignore { .. } => No,
             Inline(..) => No,
             LinkName { .. } => Yes,
+            LinkOrdinal { .. } => Yes,
             LinkSection { .. } => No,
             LoopMatch(..) => No,
             MacroTransparency(..) => Yes,

compiler/rustc_attr_parsing/messages.ftl

@@ -32,6 +32,9 @@ attr_parsing_ill_formed_attribute_input = {$num_suggestions ->
         *[other] valid forms for the attribute are {$suggestions}
     }
 
+attr_parsing_illegal_link_ordinal_format = illegal ordinal format in `link_ordinal`
+    .note = an unsuffixed integer value, e.g., `1`, is expected
+
 attr_parsing_incorrect_repr_format_align_one_arg =
     incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
 
@@ -78,6 +81,9 @@ attr_parsing_invalid_repr_hint_no_value =
 attr_parsing_invalid_since =
     'since' must be a Rust version number, such as "1.31.0"
 
+attr_parsing_link_ordinal_out_of_range = ordinal value in `link_ordinal` is too large: `{$ordinal}`
+    .note = the value may not exceed `u16::MAX`
+
 attr_parsing_missing_feature =
     missing 'feature'
 

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -1,11 +1,13 @@
+use rustc_ast::{LitIntType, LitKind, MetaItemLit};
 use rustc_attr_data_structures::AttributeKind;
-use rustc_attr_data_structures::AttributeKind::{LinkName, LinkSection};
+use rustc_attr_data_structures::AttributeKind::{LinkName, LinkOrdinal, LinkSection};
 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;
+use crate::session_diagnostics::{InvalidLinkOrdinalFormat, LinkOrdinalOutOfRange};
 use crate::session_diagnostics::NullOnLinkSection;
 
 pub(crate) struct LinkNameParser;
@@ -57,3 +59,51 @@ impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
         Some(LinkSection { name, span: cx.attr_span })
     }
 }
+
+pub(crate) struct LinkOrdinalParser;
+
+impl<S: Stage> SingleAttributeParser<S> for LinkOrdinalParser {
+    const PATH: &[Symbol] = &[sym::link_ordinal];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const TEMPLATE: AttributeTemplate = template!(List: "ordinal");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let Some(arg_list) = args.list() else {
+            cx.expected_list(cx.attr_span);
+            return None;
+        };
+
+        let Some(single_arg) = arg_list.single() else {
+            cx.expected_single_argument(cx.attr_span);
+            return None;
+        };
+
+        let Some(MetaItemLit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) =
+            single_arg.lit()
+        else {
+            cx.emit_err(InvalidLinkOrdinalFormat { span: cx.attr_span });
+            return None;
+        };
+
+        // According to the table at
+        // https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-header, the
+        // ordinal must fit into 16 bits. Similarly, the Ordinal field in COFFShortExport (defined
+        // in llvm/include/llvm/Object/COFFImportFile.h), which we use to communicate import
+        // information to LLVM for `#[link(kind = "raw-dylib"_])`, is also defined to be uint16_t.
+        //
+        // FIXME: should we allow an ordinal of 0?  The MSVC toolchain has inconsistent support for
+        // this: both LINK.EXE and LIB.EXE signal errors and abort when given a .DEF file that
+        // specifies a zero ordinal. However, llvm-dlltool is perfectly happy to generate an import
+        // library for such a .DEF file, and MSVC's LINK.EXE is also perfectly happy to consume an
+        // import library produced by LLVM with an ordinal of 0, and it generates an .EXE.  (I
+        // don't know yet if the resulting EXE runs, as I haven't yet built the necessary DLL --
+        // see earlier comment about LINK.EXE failing.)
+        let Ok(ordinal) = ordinal.get().try_into() else {
+            cx.emit_err(LinkOrdinalOutOfRange { span: cx.attr_span, ordinal: ordinal.get() });
+            return None;
+        };
+
+        Some(LinkOrdinal { ordinal, span: cx.attr_span })
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -22,8 +22,8 @@ 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::lint_helpers::{AsPtrParser, PassByValueParser, PubTransparentParser};
+use crate::attributes::link_attrs::{LinkNameParser, LinkSectionParser, LinkOrdinalParser};
+use crate::attributes::lint_helpers::{AsPtrParser, PubTransparentParser};
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
 use crate::attributes::must_use::MustUseParser;
 use crate::attributes::no_implicit_prelude::NoImplicitPreludeParser;
@@ -130,6 +130,7 @@ attribute_parsers!(
         Single<IgnoreParser>,
         Single<InlineParser>,
         Single<LinkNameParser>,
+        Single<LinkOrdinalParser>,
         Single<LinkSectionParser>,
         Single<MustUseParser>,
         Single<OptimizeParser>,

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -514,6 +514,23 @@ pub(crate) struct NakedFunctionIncompatibleAttribute {
     pub attr: String,
 }
 
+#[derive(Diagnostic)]
+#[diag(attr_parsing_illegal_link_ordinal_format)]
+#[note]
+pub(crate) struct InvalidLinkOrdinalFormat {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_link_ordinal_out_of_range)]
+#[note]
+pub(crate) struct LinkOrdinalOutOfRange {
+    #[primary_span]
+    pub span: Span,
+    pub ordinal: u128,
+}
+
 pub(crate) enum AttributeParseErrorReason {
     ExpectedNoArgs,
     ExpectedStringLiteral { byte_string: Option<Span> },

compiler/rustc_codegen_ssa/messages.ftl

@@ -80,9 +80,6 @@ codegen_ssa_ignoring_emit_path = ignoring emit path because multiple .{$extensio
 
 codegen_ssa_ignoring_output = ignoring -o because multiple .{$extension} files were produced
 
-codegen_ssa_illegal_link_ordinal_format = illegal ordinal format in `link_ordinal`
-    .note = an unsuffixed integer value, e.g., `1`, is expected
-
 codegen_ssa_incorrect_cgu_reuse_type =
     CGU-reuse for `{$cgu_user_name}` is `{$actual_reuse}` but should be {$at_least ->
     [one] {"at least "}
@@ -93,9 +90,6 @@ codegen_ssa_insufficient_vs_code_product = VS Code is a different product, and i
 
 codegen_ssa_invalid_instruction_set = invalid instruction set specified
 
-codegen_ssa_invalid_link_ordinal_nargs = incorrect number of arguments to `#[link_ordinal]`
-    .note = the attribute requires exactly one argument
-
 codegen_ssa_invalid_literal_value = invalid literal value
     .label = value must be an integer between `0` and `255`
 

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -124,6 +124,10 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                 AttributeKind::Naked(_) => codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED,
                 AttributeKind::Align { align, .. } => codegen_fn_attrs.alignment = Some(*align),
                 AttributeKind::LinkName { name, .. } => codegen_fn_attrs.link_name = Some(*name),
+                AttributeKind::LinkOrdinal { ordinal, span } => {
+                    codegen_fn_attrs.link_ordinal = Some(*ordinal);
+                    link_ordinal_span = Some(*span);
+                }
                 AttributeKind::LinkSection { name, .. } => {
                     codegen_fn_attrs.link_section = Some(*name)
                 }
@@ -256,12 +260,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                     }
                 }
             }
-            sym::link_ordinal => {
-                link_ordinal_span = Some(attr.span());
-                if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) {
-                    codegen_fn_attrs.link_ordinal = ordinal;
-                }
-            }
             sym::no_sanitize => {
                 no_sanitize_span = Some(attr.span());
                 if let Some(list) = attr.meta_item_list() {
@@ -574,45 +572,6 @@ fn inherited_align<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<Align> {
     tcx.codegen_fn_attrs(opt_trait_item(tcx, def_id)?).alignment
 }
 
-fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &hir::Attribute) -> Option<u16> {
-    use rustc_ast::{LitIntType, LitKind, MetaItemLit};
-    let meta_item_list = attr.meta_item_list()?;
-    let [sole_meta_list] = &meta_item_list[..] else {
-        tcx.dcx().emit_err(errors::InvalidLinkOrdinalNargs { span: attr.span() });
-        return None;
-    };
-    if let Some(MetaItemLit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) =
-        sole_meta_list.lit()
-    {
-        // According to the table at
-        // https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-header, the
-        // ordinal must fit into 16 bits. Similarly, the Ordinal field in COFFShortExport (defined
-        // in llvm/include/llvm/Object/COFFImportFile.h), which we use to communicate import
-        // information to LLVM for `#[link(kind = "raw-dylib"_])`, is also defined to be uint16_t.
-        //
-        // FIXME: should we allow an ordinal of 0?  The MSVC toolchain has inconsistent support for
-        // this: both LINK.EXE and LIB.EXE signal errors and abort when given a .DEF file that
-        // specifies a zero ordinal. However, llvm-dlltool is perfectly happy to generate an import
-        // library for such a .DEF file, and MSVC's LINK.EXE is also perfectly happy to consume an
-        // import library produced by LLVM with an ordinal of 0, and it generates an .EXE.  (I
-        // don't know yet if the resulting EXE runs, as I haven't yet built the necessary DLL --
-        // see earlier comment about LINK.EXE failing.)
-        if *ordinal <= u16::MAX as u128 {
-            Some(ordinal.get() as u16)
-        } else {
-            let msg = format!("ordinal value in `link_ordinal` is too large: `{ordinal}`");
-            tcx.dcx()
-                .struct_span_err(attr.span(), msg)
-                .with_note("the value may not exceed `u16::MAX`")
-                .emit();
-            None
-        }
-    } else {
-        tcx.dcx().emit_err(errors::InvalidLinkOrdinalFormat { span: attr.span() });
-        None
-    }
-}
-
 fn check_link_name_xor_ordinal(
     tcx: TyCtxt<'_>,
     codegen_fn_attrs: &CodegenFnAttrs,

compiler/rustc_codegen_ssa/src/errors.rs

@@ -1101,22 +1101,6 @@ pub(crate) struct InvalidNoSanitize {
     pub span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_invalid_link_ordinal_nargs)]
-#[note]
-pub(crate) struct InvalidLinkOrdinalNargs {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_illegal_link_ordinal_format)]
-#[note]
-pub(crate) struct InvalidLinkOrdinalFormat {
-    #[primary_span]
-    pub span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(codegen_ssa_target_feature_safe_trait)]
 pub(crate) struct TargetFeatureSafeTrait {

compiler/rustc_metadata/src/native_libs.rs

@@ -3,6 +3,7 @@ use std::path::{Path, PathBuf};
 
 use rustc_abi::ExternAbi;
 use rustc_ast::CRATE_NODE_ID;
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_attr_parsing as attr;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::query::LocalCrate;
@@ -496,14 +497,9 @@ impl<'tcx> Collector<'tcx> {
                 }
                 _ => {
                     for &child_item in foreign_items {
-                        if self.tcx.def_kind(child_item).has_codegen_attrs()
-                            && self.tcx.codegen_fn_attrs(child_item).link_ordinal.is_some()
+                        if let Some(span) = find_attr!(self.tcx.get_all_attrs(child_item), AttributeKind::LinkOrdinal {span, ..} => *span)
                         {
-                            let link_ordinal_attr =
-                                self.tcx.get_attr(child_item, sym::link_ordinal).unwrap();
-                            sess.dcx().emit_err(errors::LinkOrdinalRawDylib {
-                                span: link_ordinal_attr.span(),
-                            });
+                            sess.dcx().emit_err(errors::LinkOrdinalRawDylib { span });
                         }
                     }