Stabilize c_variadic

Author: folkertdev

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -1,4 +1,4 @@
-use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
+use rustc_ast::visit::{self, AssocCtxt, FnKind, Visitor};
 use rustc_ast::{self as ast, AttrVec, GenericBound, NodeId, PatKind, attr, token};
 use rustc_attr_parsing::AttributeParser;
 use rustc_errors::msg;
@@ -388,7 +388,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         visit::walk_poly_trait_ref(self, t);
     }
 
-    fn visit_fn(&mut self, fn_kind: FnKind<'a>, _: &AttrVec, span: Span, _: NodeId) {
+    fn visit_fn(&mut self, fn_kind: FnKind<'a>, _: &AttrVec, _: Span, _: NodeId) {
         if let Some(_header) = fn_kind.header() {
             // Stability of const fn methods are covered in `visit_assoc_item` below.
         }
@@ -397,10 +397,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             self.check_late_bound_lifetime_defs(generic_params);
         }
 
-        if fn_kind.ctxt() != Some(FnCtxt::Foreign) && fn_kind.decl().c_variadic() {
-            gate!(self, c_variadic, span, "C-variadic functions are unstable");
-        }
-
         visit::walk_fn(self, fn_kind)
     }
 

compiler/rustc_feature/src/accepted.rs

@@ -94,6 +94,8 @@ declare_features! (
     (accepted, c_str_literals, "1.77.0", Some(105723)),
     /// Allows `extern "C-unwind" fn` to enable unwinding across ABI boundaries and treat `extern "C" fn` as nounwind.
     (accepted, c_unwind, "1.81.0", Some(74990)),
+    /// Allows using C-variadics.
+    (accepted, c_variadic, "CURRENT_RUSTC_VERSION", Some(44930)),
     /// Allows `#[cfg_attr(predicate, multiple, attributes, here)]`.
     (accepted, cfg_attr_multi, "1.33.0", Some(54881)),
     /// Allows the use of `#[cfg(<true/false>)]`.

compiler/rustc_feature/src/unstable.rs

@@ -391,8 +391,6 @@ declare_features! (
     (unstable, avx10_target_feature, "1.88.0", Some(138843)),
     /// Target features on bpf.
     (unstable, bpf_target_feature, "1.54.0", Some(150247)),
-    /// Allows using C-variadics.
-    (unstable, c_variadic, "1.34.0", Some(44930)),
     /// Allows defining c-variadic naked functions with any extern ABI that is allowed
     /// on c-variadic foreign functions.
     (unstable, c_variadic_naked_functions, "1.93.0", Some(148767)),

library/core/src/ffi/mod.rs

@@ -23,20 +23,10 @@ use crate::fmt;
 #[stable(feature = "c_str_module", since = "1.88.0")]
 pub mod c_str;
 
-#[unstable(
-    feature = "c_variadic",
-    issue = "44930",
-    reason = "the `c_variadic` feature has not been properly tested on all supported platforms"
-)]
+mod va_list;
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 pub use self::va_list::{VaArgSafe, VaList};
 
-#[unstable(
-    feature = "c_variadic",
-    issue = "44930",
-    reason = "the `c_variadic` feature has not been properly tested on all supported platforms"
-)]
-pub mod va_list;
-
 mod primitives;
 #[stable(feature = "core_ffi_c", since = "1.64.0")]
 pub use self::primitives::{

library/core/src/ffi/va_list.rs

@@ -189,8 +189,6 @@ crate::cfg_select! {
 /// is automatically initialized (equivalent to calling `va_start` in C).
 ///
 /// ```
-/// #![feature(c_variadic)]
-///
 /// use std::ffi::VaList;
 ///
 /// /// # Safety
@@ -224,11 +222,13 @@ crate::cfg_select! {
 /// terms of layout and ABI.
 #[repr(transparent)]
 #[lang = "va_list"]
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 pub struct VaList<'a> {
     inner: VaListInner,
     _marker: PhantomCovariantLifetime<'a>,
 }
 
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 impl fmt::Debug for VaList<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // No need to include `_marker` in debug output.
@@ -243,6 +243,7 @@ impl VaList<'_> {
     }
 }
 
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 #[rustc_const_unstable(feature = "const_c_variadic", issue = "151787")]
 impl<'f> const Clone for VaList<'f> {
     #[inline] // Avoid codegen when not used to help backends that don't support VaList.
@@ -255,6 +256,7 @@ impl<'f> const Clone for VaList<'f> {
     }
 }
 
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 #[rustc_const_unstable(feature = "const_c_variadic", issue = "151787")]
 impl<'f> const Drop for VaList<'f> {
     #[inline] // Avoid codegen when not used to help backends that don't support VaList.
@@ -264,6 +266,7 @@ impl<'f> const Drop for VaList<'f> {
     }
 }
 
+#[unstable(feature = "c_variadic_internals", issue = "none")]
 mod sealed {
     pub trait Sealed {}
 
@@ -318,6 +321,7 @@ mod sealed {
 // types with an alignment larger than 8, or with a non-scalar layout. Inline assembly can be used
 // to accept unsupported types in the meantime.
 #[lang = "va_arg_safe"]
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 pub unsafe trait VaArgSafe: sealed::Sealed {}
 
 crate::cfg_select! {
@@ -326,7 +330,9 @@ crate::cfg_select! {
         //
         // - i8 is implicitly promoted to c_int in C, and cannot implement `VaArgSafe`.
         // - u8 is implicitly promoted to c_uint in C, and cannot implement `VaArgSafe`.
+        #[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
         unsafe impl VaArgSafe for i16 {}
+        #[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
         unsafe impl VaArgSafe for u16 {}
     }
     _ => {
@@ -340,6 +346,7 @@ crate::cfg_select! {
 crate::cfg_select! {
     target_arch = "avr" => {
         // c_double is f32 on this target.
+        #[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
         unsafe impl VaArgSafe for f32 {}
     }
     _ => {
@@ -349,17 +356,26 @@ crate::cfg_select! {
     }
 }
 
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl VaArgSafe for i32 {}
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl VaArgSafe for i64 {}
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl VaArgSafe for isize {}
 
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl VaArgSafe for u32 {}
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl VaArgSafe for u64 {}
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl VaArgSafe for usize {}
 
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl VaArgSafe for f64 {}
 
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl<T> VaArgSafe for *mut T {}
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 unsafe impl<T> VaArgSafe for *const T {}
 
 // Check that relevant `core::ffi` types implement `VaArgSafe`.
@@ -390,6 +406,7 @@ impl<'f> VaList<'f> {
     /// Calling this function with an incompatible type, an invalid value, or when there
     /// are no more variable arguments, is unsound.
     #[inline] // Avoid codegen when not used to help backends that don't support VaList.
+    #[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
     #[rustc_const_unstable(feature = "const_c_variadic", issue = "151787")]
     pub const unsafe fn next_arg<T: VaArgSafe>(&mut self) -> T {
         // SAFETY: the caller must uphold the safety contract for `va_arg`.

library/core/src/intrinsics/mod.rs

@@ -53,7 +53,7 @@
     issue = "none"
 )]
 
-use crate::ffi::va_list::{VaArgSafe, VaList};
+use crate::ffi::{VaArgSafe, VaList};
 use crate::marker::{ConstParamTy, DiscriminantKind, PointeeSized, Tuple};
 use crate::{mem, ptr};
 

library/std/src/ffi/mod.rs

@@ -166,12 +166,7 @@ pub mod c_str;
 
 #[stable(feature = "core_c_void", since = "1.30.0")]
 pub use core::ffi::c_void;
-#[unstable(
-    feature = "c_variadic",
-    reason = "the `c_variadic` feature has not been properly tested on \
-              all supported platforms",
-    issue = "44930"
-)]
+#[stable(feature = "c_variadic", since = "CURRENT_RUSTC_VERSION")]
 pub use core::ffi::{VaArgSafe, VaList};
 #[stable(feature = "core_ffi_c", since = "1.64.0")]
 pub use core::ffi::{

library/std/src/lib.rs

@@ -403,7 +403,6 @@
 // Only for re-exporting:
 // tidy-alphabetical-start
 #![feature(async_iterator)]
-#![feature(c_variadic)]
 #![feature(cfg_accessible)]
 #![feature(cfg_eval)]
 #![feature(concat_bytes)]

src/doc/unstable-book/src/language-features/c-variadic.md

@@ -1,5 +1,3 @@
-#![feature(c_variadic)]
-
 unsafe extern "C" fn helper(_: i32, _: ...) {}
 
 fn main() {