Stabilize target_feature_11

Author: calebzulawski

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -255,10 +255,9 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                 {
                     if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc {
                         // The `#[target_feature]` attribute is allowed on
-                        // WebAssembly targets on all functions, including safe
-                        // ones. Other targets require that `#[target_feature]` is
-                        // only applied to unsafe functions (pending the
-                        // `target_feature_11` feature) because on most targets
+                        // WebAssembly targets on all functions. Prior to stabilizing
+                        // the `target_feature_11` feature, `#[target_feature]` was
+                        // only permitted on safe functions because on most targets
                         // execution of instructions that are not supported is
                         // considered undefined behavior. For WebAssembly which is a
                         // 100% safe target at execution time it's not possible to
@@ -272,17 +271,10 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                         // if a target is documenting some wasm-specific code then
                         // it's not spuriously denied.
                         //
-                        // This exception needs to be kept in sync with allowing
-                        // `#[target_feature]` on `main` and `start`.
-                    } else if !tcx.features().target_feature_11() {
-                        feature_err(
-                            &tcx.sess,
-                            sym::target_feature_11,
-                            attr.span,
-                            "`#[target_feature(..)]` can only be applied to `unsafe` functions",
-                        )
-                        .with_span_label(tcx.def_span(did), "not an `unsafe` function")
-                        .emit();
+                        // Now that `#[target_feature]` is permitted on safe functions,
+                        // this exception must still exist for allowing the attribute on
+                        // `main`, `start`, and other functions that are not usually
+                        // allowed.
                     } else {
                         check_target_feature_trait_unsafe(tcx, did, attr.span);
                     }
@@ -599,10 +591,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
     // its parent function, which effectively inherits the features anyway. Boxing this closure
     // would result in this closure being compiled without the inherited target features, but this
     // is probably a poor usage of `#[inline(always)]` and easily avoided by not using the attribute.
-    if tcx.features().target_feature_11()
-        && tcx.is_closure_like(did.to_def_id())
-        && codegen_fn_attrs.inline != InlineAttr::Always
-    {
+    if tcx.is_closure_like(did.to_def_id()) && codegen_fn_attrs.inline != InlineAttr::Always {
         let owner_id = tcx.parent(did.to_def_id());
         if tcx.def_kind(owner_id).has_codegen_attrs() {
             codegen_fn_attrs

compiler/rustc_feature/src/accepted.rs

@@ -387,6 +387,8 @@ declare_features! (
     (accepted, struct_variant, "1.0.0", None),
     /// Allows `#[target_feature(...)]`.
     (accepted, target_feature, "1.27.0", None),
+    /// Allows the use of `#[target_feature]` on safe functions.
+    (accepted, target_feature_11, "CURRENT_RUSTC_VERSION", Some(69098)),
     /// Allows `fn main()` with return types which implements `Termination` (RFC 1937).
     (accepted, termination_trait, "1.26.0", Some(43301)),
     /// Allows `#[test]` functions where the return type implements `Termination` (RFC 1937).

compiler/rustc_feature/src/unstable.rs

@@ -613,8 +613,6 @@ declare_features! (
     (unstable, strict_provenance_lints, "1.61.0", Some(130351)),
     /// Allows string patterns to dereference values to match them.
     (unstable, string_deref_patterns, "1.67.0", Some(87121)),
-    /// Allows the use of `#[target_feature]` on safe functions.
-    (unstable, target_feature_11, "1.45.0", Some(69098)),
     /// Allows using `#[thread_local]` on `static` items.
     (unstable, thread_local, "1.0.0", Some(29594)),
     /// Allows defining `trait X = A + B;` alias items.

library/core/src/lib.rs

@@ -187,7 +187,6 @@
 #![feature(staged_api)]
 #![feature(stmt_expr_attributes)]
 #![feature(strict_provenance_lints)]
-#![feature(target_feature_11)]
 #![feature(trait_alias)]
 #![feature(transparent_unions)]
 #![feature(try_blocks)]

tests/assembly/closure-inherit-target-feature.rs

@@ -4,7 +4,6 @@
 // make sure the feature is not enabled at compile-time
 //@ compile-flags: -C opt-level=3 -C target-feature=-sse4.1 -C llvm-args=-x86-asm-syntax=intel
 
-#![feature(target_feature_11)]
 #![crate_type = "rlib"]
 
 use std::arch::x86_64::{__m128, _mm_blend_ps};

tests/codegen/target-feature-inline-closure.rs

@@ -3,7 +3,6 @@
 //@ compile-flags: -Copt-level=3 -Ctarget-cpu=x86-64
 
 #![crate_type = "lib"]
-#![feature(target_feature_11)]
 
 #[cfg(target_arch = "x86_64")]
 use std::arch::x86_64::*;

tests/mir-opt/inline/inline_compatibility.rs

@@ -4,7 +4,6 @@
 
 #![crate_type = "lib"]
 #![feature(no_sanitize)]
-#![feature(target_feature_11)]
 #![feature(c_variadic)]
 
 #[inline]

tests/ui/asm/x86_64/issue-89875.rs

@@ -2,8 +2,6 @@
 //@ needs-asm-support
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-
 use std::arch::asm;
 
 #[target_feature(enable = "avx")]

tests/ui/async-await/async-closures/fn-exception-target-features.rs

@@ -1,14 +1,13 @@
 //@ edition: 2021
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-// `target_feature_11` just to test safe functions w/ target features.
-
-use std::pin::Pin;
 use std::future::Future;
+use std::pin::Pin;
 
 #[target_feature(enable = "sse2")]
-fn target_feature()  -> Pin<Box<dyn Future<Output = ()> + 'static>> { todo!() }
+fn target_feature() -> Pin<Box<dyn Future<Output = ()> + 'static>> {
+    todo!()
+}
 
 fn test(f: impl AsyncFn()) {}
 

tests/ui/async-await/async-closures/fn-exception-target-features.stderr

@@ -1,13 +1,13 @@
 error[E0277]: the trait bound `fn() -> Pin<Box<(dyn Future<Output = ()> + 'static)>> {target_feature}: AsyncFn()` is not satisfied
-  --> $DIR/fn-exception-target-features.rs:16:10
+  --> $DIR/fn-exception-target-features.rs:15:10
    |
 LL |     test(target_feature);
    |     ---- ^^^^^^^^^^^^^^ the trait `AsyncFn()` is not implemented for fn item `fn() -> Pin<Box<(dyn Future<Output = ()> + 'static)>> {target_feature}`
    |     |
    |     required by a bound introduced by this call
    |
 note: required by a bound in `test`
-  --> $DIR/fn-exception-target-features.rs:13:17
+  --> $DIR/fn-exception-target-features.rs:12:17
    |
 LL | fn test(f: impl AsyncFn()) {}
    |                 ^^^^^^^^^ required by this bound in `test`

tests/ui/lang-items/start_lang_item_with_target_feature.rs

@@ -1,7 +1,7 @@
 //@ only-x86_64
 //@ check-fail
 
-#![feature(lang_items, no_core, target_feature_11)]
+#![feature(lang_items, no_core)]
 #![no_core]
 
 #[lang = "copy"]

tests/ui/panic-handler/panic-handler-with-target-feature.rs

@@ -1,7 +1,6 @@
 //@ compile-flags:-C panic=abort
 //@ only-x86_64
 
-#![feature(target_feature_11)]
 #![no_std]
 #![no_main]
 

tests/ui/panic-handler/panic-handler-with-target-feature.stderr

@@ -1,5 +1,5 @@
 error: `#[panic_handler]` function is not allowed to have `#[target_feature]`
-  --> $DIR/panic-handler-with-target-feature.rs:11:1
+  --> $DIR/panic-handler-with-target-feature.rs:10:1
    |
 LL | #[target_feature(enable = "avx2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/rfcs/rfc-2396-target_feature-11/check-pass.rs

@@ -9,8 +9,6 @@
 //@ check-pass
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-
 #[target_feature(enable = "sse2")]
 const fn sse2() {}
 

tests/ui/rfcs/rfc-2396-target_feature-11/closures-inherit-target_feature.rs

@@ -3,8 +3,6 @@
 //@ check-pass
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-
 #[target_feature(enable = "avx")]
 fn also_use_avx() {
     println!("Hello from AVX")

tests/ui/rfcs/rfc-2396-target_feature-11/feature-gate-target_feature_11.rs

@@ -1,7 +1,5 @@
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-
 #[target_feature(enable = "sse2")]
 fn foo() {}
 

tests/ui/rfcs/rfc-2396-target_feature-11/feature-gate-target_feature_11.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/fn-ptr.rs:9:21
+  --> $DIR/fn-ptr.rs:7:21
    |
 LL | #[target_feature(enable = "sse2")]
    | ---------------------------------- `#[target_feature]` added here

tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.rs

@@ -0,0 +1,23 @@
+error[E0308]: mismatched types
+  --> $DIR/fn-ptr.rs:9:21
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ---------------------------------- `#[target_feature]` added here
+...
+LL |     let foo: fn() = foo;
+   |              ----   ^^^ cannot coerce functions with `#[target_feature]` to safe function pointers
+   |              |
+   |              expected due to this
+   |
+   = note: expected fn pointer `fn()`
+                 found fn item `fn() {foo}`
+   = note: fn items are distinct from fn pointers
+   = note: functions with `#[target_feature]` can only be coerced to `unsafe` function pointers
+help: consider casting to a fn pointer
+   |
+LL |     let foo: fn() = foo as fn();
+   |                     ~~~~~~~~~~~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.stderr

@@ -1,7 +1,5 @@
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-
 #[target_feature(enable = "avx")]
 fn foo() {}
 

tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.thir.stderr

@@ -1,5 +1,5 @@
 error[E0277]: expected a `Fn()` closure, found `fn() {foo}`
-  --> $DIR/fn-traits.rs:24:10
+  --> $DIR/fn-traits.rs:22:10
    |
 LL |     call(foo);
    |     ---- ^^^ expected an `Fn()` closure, found `fn() {foo}`
@@ -10,13 +10,13 @@ LL |     call(foo);
    = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call`
-  --> $DIR/fn-traits.rs:11:17
+  --> $DIR/fn-traits.rs:9:17
    |
 LL | fn call(f: impl Fn()) {
    |                 ^^^^ required by this bound in `call`
 
 error[E0277]: expected a `FnMut()` closure, found `fn() {foo}`
-  --> $DIR/fn-traits.rs:25:14
+  --> $DIR/fn-traits.rs:23:14
    |
 LL |     call_mut(foo);
    |     -------- ^^^ expected an `FnMut()` closure, found `fn() {foo}`
@@ -27,13 +27,13 @@ LL |     call_mut(foo);
    = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_mut`
-  --> $DIR/fn-traits.rs:15:25
+  --> $DIR/fn-traits.rs:13:25
    |
 LL | fn call_mut(mut f: impl FnMut()) {
    |                         ^^^^^^^ required by this bound in `call_mut`
 
 error[E0277]: expected a `FnOnce()` closure, found `fn() {foo}`
-  --> $DIR/fn-traits.rs:26:15
+  --> $DIR/fn-traits.rs:24:15
    |
 LL |     call_once(foo);
    |     --------- ^^^ expected an `FnOnce()` closure, found `fn() {foo}`
@@ -44,13 +44,13 @@ LL |     call_once(foo);
    = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_once`
-  --> $DIR/fn-traits.rs:19:22
+  --> $DIR/fn-traits.rs:17:22
    |
 LL | fn call_once(f: impl FnOnce()) {
    |                      ^^^^^^^^ required by this bound in `call_once`
 
 error[E0277]: expected a `Fn()` closure, found `unsafe fn() {foo_unsafe}`
-  --> $DIR/fn-traits.rs:28:10
+  --> $DIR/fn-traits.rs:26:10
    |
 LL |     call(foo_unsafe);
    |     ---- ^^^^^^^^^^ call the function in a closure: `|| unsafe { /* code */ }`
@@ -62,13 +62,13 @@ LL |     call(foo_unsafe);
    = note: wrap the `unsafe fn() {foo_unsafe}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call`
-  --> $DIR/fn-traits.rs:11:17
+  --> $DIR/fn-traits.rs:9:17
    |
 LL | fn call(f: impl Fn()) {
    |                 ^^^^ required by this bound in `call`
 
 error[E0277]: expected a `FnMut()` closure, found `unsafe fn() {foo_unsafe}`
-  --> $DIR/fn-traits.rs:30:14
+  --> $DIR/fn-traits.rs:28:14
    |
 LL |     call_mut(foo_unsafe);
    |     -------- ^^^^^^^^^^ call the function in a closure: `|| unsafe { /* code */ }`
@@ -80,13 +80,13 @@ LL |     call_mut(foo_unsafe);
    = note: wrap the `unsafe fn() {foo_unsafe}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_mut`
-  --> $DIR/fn-traits.rs:15:25
+  --> $DIR/fn-traits.rs:13:25
    |
 LL | fn call_mut(mut f: impl FnMut()) {
    |                         ^^^^^^^ required by this bound in `call_mut`
 
 error[E0277]: expected a `FnOnce()` closure, found `unsafe fn() {foo_unsafe}`
-  --> $DIR/fn-traits.rs:32:15
+  --> $DIR/fn-traits.rs:30:15
    |
 LL |     call_once(foo_unsafe);
    |     --------- ^^^^^^^^^^ call the function in a closure: `|| unsafe { /* code */ }`
@@ -98,7 +98,7 @@ LL |     call_once(foo_unsafe);
    = note: wrap the `unsafe fn() {foo_unsafe}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_once`
-  --> $DIR/fn-traits.rs:19:22
+  --> $DIR/fn-traits.rs:17:22
    |
 LL | fn call_once(f: impl FnOnce()) {
    |                      ^^^^^^^^ required by this bound in `call_once`

tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.rs

@@ -1,7 +1,5 @@
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-
 #[target_feature(enable = "avx2")]
 fn main() {}
 //~^ ERROR `main` function is not allowed to have `#[target_feature]`

tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr

@@ -1,5 +1,5 @@
 error: `main` function is not allowed to have `#[target_feature]`
-  --> $DIR/issue-108645-target-feature-on-main.rs:6:1
+  --> $DIR/issue-108645-target-feature-on-main.rs:4:1
    |
 LL | fn main() {}
    | ^^^^^^^^^ `main` function is not allowed to have `#[target_feature]`

tests/ui/rfcs/rfc-2396-target_feature-11/issue-108645-target-feature-on-main.rs

@@ -1,7 +1,6 @@
 //@ only-x86_64
 
 #![feature(start)]
-#![feature(target_feature_11)]
 
 #[start]
 #[target_feature(enable = "avx2")]

tests/ui/rfcs/rfc-2396-target_feature-11/issue-108645-target-feature-on-main.stderr

@@ -1,5 +1,5 @@
 error: `#[start]` function is not allowed to have `#[target_feature]`
-  --> $DIR/issue-108645-target-feature-on-start.rs:7:1
+  --> $DIR/issue-108645-target-feature-on-start.rs:6:1
    |
 LL | #[target_feature(enable = "avx2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/rfcs/rfc-2396-target_feature-11/issue-108645-target-feature-on-start.rs

@@ -3,8 +3,6 @@
 //@ check-pass
 //@ only-x86_64
 
-#![feature(target_feature_11)]
-
 #[target_feature(enable = "avx")]
 pub unsafe fn test() {
     ({

tests/ui/rfcs/rfc-2396-target_feature-11/issue-108645-target-feature-on-start.stderr

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(target_feature_11)]
-
 struct S<T>(T)
 where
     [T; (|| {}, 1).1]: Copy;