stabilize extended_varargs_abi_support

4 files changed, 27 insertions, 40 deletions

diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index eccb88a938f..08b344638dd 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -978,7 +978,7 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
                         tcx.ensure_ok().fn_sig(def_id);
                         let item = tcx.hir_foreign_item(item);
                         let hir::ForeignItemKind::Fn(sig, ..) = item.kind else { bug!() };
-                        require_c_abi_if_c_variadic(tcx, sig.decl, abi, item.span);
+                        check_c_variadic_abi(tcx, sig.decl, abi, item.span);
                     }
                     DefKind::Static { .. } => {
                         tcx.ensure_ok().codegen_fn_attrs(def_id);
diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs
index 2e4b151d4dc..b5c0ca4727c 100644
--- a/compiler/rustc_hir_analysis/src/check/mod.rs
+++ b/compiler/rustc_hir_analysis/src/check/mod.rs
@@ -98,7 +98,7 @@ use tracing::debug;
 
 use self::compare_impl_item::collect_return_position_impl_trait_in_trait_tys;
 use self::region::region_scope_tree;
-use crate::{errors, require_c_abi_if_c_variadic};
+use crate::{check_c_variadic_abi, errors};
 
 /// Adds query implementations to the [Providers] vtable, see [`rustc_middle::query`]
 pub(super) fn provide(providers: &mut Providers) {
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
index c7b984d9b25..c5e079fe89a 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
@@ -52,11 +52,11 @@ use rustc_trait_selection::traits::{self, FulfillmentError};
 use tracing::{debug, instrument};
 
 use crate::check::check_abi;
+use crate::check_c_variadic_abi;
 use crate::errors::{AmbiguousLifetimeBound, BadReturnTypeNotation};
 use crate::hir_ty_lowering::errors::{GenericsArgsErrExtend, prohibit_assoc_item_constraint};
 use crate::hir_ty_lowering::generics::{check_generic_arg_count, lower_generic_args};
 use crate::middle::resolve_bound_vars as rbv;
-use crate::require_c_abi_if_c_variadic;
 
 /// A path segment that is semantically allowed to have generic arguments.
 #[derive(Debug)]
@@ -2412,7 +2412,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 Ty::new_tup_from_iter(tcx, fields.iter().map(|t| self.lower_ty(t)))
             }
             hir::TyKind::FnPtr(bf) => {
-                require_c_abi_if_c_variadic(tcx, bf.decl, bf.abi, hir_ty.span);
+                check_c_variadic_abi(tcx, bf.decl, bf.abi, hir_ty.span);
 
                 Ty::new_fn_ptr(
                     tcx,
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index 44a5ceed469..2562ab7542a 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -90,7 +90,7 @@ mod outlives;
 mod variance;
 
 pub use errors::NoVariantNamed;
-use rustc_abi::ExternAbi;
+use rustc_abi::{CVariadicStatus, ExternAbi};
 use rustc_hir::def::DefKind;
 use rustc_hir::lints::DelayedLint;
 use rustc_hir::{self as hir};
@@ -99,7 +99,6 @@ use rustc_middle::mir::interpret::GlobalId;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, Const, Ty, TyCtxt};
 use rustc_session::parse::feature_err;
-use rustc_span::symbol::sym;
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_trait_selection::traits;
 
@@ -108,46 +107,34 @@ use crate::hir_ty_lowering::{FeedConstTy, HirTyLowerer};
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 
-fn require_c_abi_if_c_variadic(
-    tcx: TyCtxt<'_>,
-    decl: &hir::FnDecl<'_>,
-    abi: ExternAbi,
-    span: Span,
-) {
-    // ABIs which can stably use varargs
-    if !decl.c_variadic || matches!(abi, ExternAbi::C { .. } | ExternAbi::Cdecl { .. }) {
+fn check_c_variadic_abi(tcx: TyCtxt<'_>, decl: &hir::FnDecl<'_>, abi: ExternAbi, span: Span) {
+    if !decl.c_variadic {
+        // Not even a variadic function.
         return;
     }
 
-    // ABIs with feature-gated stability
-    let extended_abi_support = tcx.features().extended_varargs_abi_support();
-    let extern_system_varargs = tcx.features().extern_system_varargs();
-
-    // If the feature gate has been enabled, we can stop here
-    if extern_system_varargs && let ExternAbi::System { .. } = abi {
-        return;
-    };
-    if extended_abi_support && abi.supports_varargs() {
-        return;
-    };
-
-    // Looks like we need to pick an error to emit.
-    // Is there any feature which we could have enabled to make this work?
-    let unstable_explain =
-        format!("C-variadic functions with the {abi} calling convention are unstable");
-    match abi {
-        ExternAbi::System { .. } => {
-            feature_err(&tcx.sess, sym::extern_system_varargs, span, unstable_explain)
+    match abi.supports_c_variadic() {
+        CVariadicStatus::Stable => {}
+        CVariadicStatus::NotSupported => {
+            tcx.dcx()
+                .create_err(errors::VariadicFunctionCompatibleConvention {
+                    span,
+                    convention: &format!("{abi}"),
+                })
+                .emit();
         }
-        abi if abi.supports_varargs() => {
-            feature_err(&tcx.sess, sym::extended_varargs_abi_support, span, unstable_explain)
+        CVariadicStatus::Unstable { feature } => {
+            if !tcx.features().enabled(feature) {
+                feature_err(
+                    &tcx.sess,
+                    feature,
+                    span,
+                    format!("C-variadic functions with the {abi} calling convention are unstable"),
+                )
+                .emit();
+            }
         }
-        _ => tcx.dcx().create_err(errors::VariadicFunctionCompatibleConvention {
-            span,
-            convention: &format!("{abi}"),
-        }),
     }
-    .emit();
 }
 
 /// Adds query implementations to the [Providers] vtable, see [`rustc_middle::query`]