remove #[cmse_nonsecure_entry]

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -483,9 +483,6 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
         let allocated_pointer = AttributeKind::AllocatedPointer.create_attr(cx.llcx);
         attributes::apply_to_llfn(llfn, AttributePlace::Argument(0), &[allocated_pointer]);
     }
-    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY) {
-        to_add.push(llvm::CreateAttrString(cx.llcx, "cmse_nonsecure_entry"));
-    }
     if let Some(align) = codegen_fn_attrs.alignment {
         llvm::set_alignment(llfn, align);
     }

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -195,24 +195,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                     }
                 }
             }
-            sym::cmse_nonsecure_entry => {
-                if let Some(fn_sig) = fn_sig()
-                    && !matches!(fn_sig.skip_binder().abi(), abi::Abi::C { .. })
-                {
-                    struct_span_code_err!(
-                        tcx.dcx(),
-                        attr.span,
-                        E0776,
-                        "`#[cmse_nonsecure_entry]` requires C ABI"
-                    )
-                    .emit();
-                }
-                if !tcx.sess.target.llvm_target.contains("thumbv8m") {
-                    struct_span_code_err!(tcx.dcx(), attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension")
-                    .emit();
-                }
-                codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY
-            }
             sym::thread_local => codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL,
             sym::track_caller => {
                 let is_closure = tcx.is_closure_like(did.to_def_id());

compiler/rustc_error_codes/src/error_codes/E0775.md

@@ -3,11 +3,10 @@ extension.
 
 Erroneous code example:
 
-```compile_fail,E0775
+```ignore (no longer emitted)
 #![feature(cmse_nonsecure_entry)]
 
-#[cmse_nonsecure_entry]
+pub extern "C-cmse-nonsecure-entry" fn entry_function() {}
-pub extern "C" fn entry_function() {}
 ```
 
 To fix this error, compile your code for a Rust target that supports the

compiler/rustc_error_codes/src/error_codes/E0776.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 `#[cmse_nonsecure_entry]` functions require a C ABI
 
 Erroneous code example:
 
-```compile_fail,E0776
+```ignore (no longer emitted)
 #![feature(cmse_nonsecure_entry)]
 
 #[no_mangle]

compiler/rustc_error_codes/src/lib.rs

@@ -681,4 +681,5 @@ E0800: 0800,
 //  E0723, // unstable feature in `const` context
 //  E0738, // Removed; errored on `#[track_caller] fn`s in `extern "Rust" { ... }`.
 //  E0744, // merged into E0728
+//  E0776, // Removed; cmse_nonsecure_entry is now `C-cmse-nonsecure-entry`
 //  E0796, // unused error code. We use `static_mut_refs` lint instead.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -551,10 +551,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         EncodeCrossCrate::No, experimental!(register_tool),
     ),
 
-    gated!(
-        cmse_nonsecure_entry, Normal, template!(Word), WarnFollowing,
-        EncodeCrossCrate::No, experimental!(cmse_nonsecure_entry)
-    ),
     // RFC 2632
     gated!(
         const_trait, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No, const_trait_impl,

compiler/rustc_feature/src/unstable.rs

@@ -395,7 +395,7 @@ declare_features! (
     (unstable, closure_lifetime_binder, "1.64.0", Some(97362)),
     /// Allows `#[track_caller]` on closures and coroutines.
     (unstable, closure_track_caller, "1.57.0", Some(87417)),
-    /// Allows to use the `#[cmse_nonsecure_entry]` attribute.
+    /// Allows `extern "C-cmse-nonsecure-entry" fn()`.
     (unstable, cmse_nonsecure_entry, "1.48.0", Some(75835)),
     /// Allows `async {}` expressions in const contexts.
     (unstable, const_async_blocks, "1.53.0", Some(85368)),

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

@@ -120,9 +120,7 @@ bitflags::bitflags! {
         /// #[ffi_const]: applies clang's `const` attribute to a foreign function
         /// declaration.
         const FFI_CONST                 = 1 << 12;
-        /// #[cmse_nonsecure_entry]: with a TrustZone-M extension, declare a
+        // (Bit 13 was used for `#[cmse_nonsecure_entry]`, but is now unused.)
-        /// function as an entry function from Non-Secure code.
-        const CMSE_NONSECURE_ENTRY      = 1 << 13;
         // (Bit 14 was used for `#[coverage(off)]`, but is now unused.)
         /// `#[used(linker)]`:
         /// indicates that neither LLVM nor the linker will eliminate this function.

compiler/rustc_passes/src/check_attr.rs

@@ -188,9 +188,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 | [sym::rustc_must_implement_one_of, ..]
                 | [sym::rustc_deny_explicit_impl, ..]
                 | [sym::const_trait, ..] => self.check_must_be_applied_to_trait(attr, span, target),
-                [sym::cmse_nonsecure_entry, ..] => {
-                    self.check_cmse_nonsecure_entry(hir_id, attr, span, target)
-                }
                 [sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),
                 [sym::must_not_suspend, ..] => self.check_must_not_suspend(attr, span, target),
                 [sym::must_use, ..] => self.check_must_use(hir_id, attr, target),
@@ -563,27 +560,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
-    fn check_cmse_nonsecure_entry(
-        &self,
-        hir_id: HirId,
-        attr: &Attribute,
-        span: Span,
-        target: Target,
-    ) {
-        match target {
-            Target::Fn
-            | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => {}
-            _ => {
-                self.dcx().emit_err(errors::AttrShouldBeAppliedToFn {
-                    attr_span: attr.span,
-                    defn_span: span,
-                    on_crate: hir_id == CRATE_HIR_ID,
-                });
-            }
-        }
-    }
-
     /// Debugging aid for `object_lifetime_default` query.
     fn check_object_lifetime_default(&self, hir_id: HirId) {
         let tcx = self.tcx;

src/doc/unstable-book/src/language-features/cmse-nonsecure-entry.md

@@ -15,10 +15,10 @@ LLVM, the Rust compiler and the linker are providing
 TrustZone-M feature.
 
 One of the things provided, with this unstable feature, is the
-`cmse_nonsecure_entry` attribute.  This attribute marks a Secure function as an
+`C-cmse-nonsecure-entry` ABI. This ABI marks a Secure function as an
 entry function (see [section
 5.4](https://developer.arm.com/documentation/ecm0359818/latest/) for details).
-With this attribute, the compiler will do the following:
+With this ABI, the compiler will do the following:
 * add a special symbol on the function which is the `__acle_se_` prefix and the
   standard function name
 * constrain the number of parameters to avoid using the Non-Secure stack
@@ -38,11 +38,11 @@ gateway veneer.
 <!-- NOTE(ignore) this example is specific to thumbv8m targets -->
 
 ``` rust,ignore
+#![no_std]
 #![feature(cmse_nonsecure_entry)]
 
 #[no_mangle]
-#[cmse_nonsecure_entry]
+pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
-pub extern "C" fn entry_function(input: u32) -> u32 {
     input + 6
 }
 ```

src/tools/tidy/src/issues.txt

@@ -467,7 +467,6 @@ ui/closures/issue-87814-2.rs
 ui/closures/issue-90871.rs
 ui/closures/issue-97607.rs
 ui/closures/issue-99565.rs
-ui/cmse-nonsecure/cmse-nonsecure-entry/issue-83475.rs
 ui/codegen/auxiliary/issue-97708-aux.rs
 ui/codegen/issue-101585-128bit-repeat.rs
 ui/codegen/issue-16602-1.rs

tests/ui/attributes/issue-105594-invalid-attr-validation.rs

@@ -1,13 +1,7 @@
 // This checks that the attribute validation ICE in issue #105594 doesn't
 // recur.
-//
-//@ ignore-thumbv8m.base-none-eabi
-#![feature(cmse_nonsecure_entry)]
 
 fn main() {}
 
 #[track_caller] //~ ERROR attribute should be applied to a function
 static _A: () = ();
-
-#[cmse_nonsecure_entry] //~ ERROR attribute should be applied to a function
-static _B: () = (); //~| ERROR #[cmse_nonsecure_entry]` is only valid for targets

tests/ui/attributes/issue-105594-invalid-attr-validation.stderr

@@ -1,26 +1,11 @@
 error[E0739]: attribute should be applied to a function definition
-  --> $DIR/issue-105594-invalid-attr-validation.rs:9:1
+  --> $DIR/issue-105594-invalid-attr-validation.rs:6:1
    |
 LL | #[track_caller]
    | ^^^^^^^^^^^^^^^
 LL | static _A: () = ();
    | ------------------- not a function definition
 
-error: attribute should be applied to a function definition
+error: aborting due to 1 previous error
-  --> $DIR/issue-105594-invalid-attr-validation.rs:12:1
-   |
-LL | #[cmse_nonsecure_entry]
-   | ^^^^^^^^^^^^^^^^^^^^^^^
-LL | static _B: () = ();
-   | ------------------- not a function definition
 
-error[E0775]: `#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension
+For more information about this error, try `rustc --explain E0739`.
-  --> $DIR/issue-105594-invalid-attr-validation.rs:12:1
-   |
-LL | #[cmse_nonsecure_entry]
-   | ^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 3 previous errors
-
-Some errors have detailed explanations: E0739, E0775.
-For more information about an error, try `rustc --explain E0739`.

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/gate_test.rs

@@ -1,10 +1,9 @@
 // gate-test-cmse_nonsecure_entry
 
 #[no_mangle]
-#[cmse_nonsecure_entry]
+pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
-//~^ ERROR [E0775]
+    //~^ ERROR [E0570]
-//~| ERROR [E0658]
+    //~| ERROR [E0658]
-pub extern "C" fn entry_function(input: u32) -> u32 {
     input + 6
 }
 

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/gate_test.stderr

@@ -1,20 +1,20 @@
-error[E0658]: the `#[cmse_nonsecure_entry]` attribute is an experimental feature
+error[E0658]: C-cmse-nonsecure-entry ABI is experimental and subject to change
-  --> $DIR/gate_test.rs:4:1
+  --> $DIR/gate_test.rs:4:12
    |
-LL | #[cmse_nonsecure_entry]
+LL | pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
-   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #75835 <https://github.com/rust-lang/rust/issues/75835> for more information
    = help: add `#![feature(cmse_nonsecure_entry)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0775]: `#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension
+error[E0570]: `"C-cmse-nonsecure-entry"` is not a supported ABI for the current target
   --> $DIR/gate_test.rs:4:1
    |
-LL | #[cmse_nonsecure_entry]
+LL | pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
-   | ^^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0658, E0775.
+Some errors have detailed explanations: E0570, E0658.
-For more information about an error, try `rustc --explain E0658`.
+For more information about an error, try `rustc --explain E0570`.

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/issue-83475.rs

@@ -1,9 +0,0 @@
-// Regression test for the ICE described in #83475.
-
-#![crate_type="lib"]
-
-#![feature(cmse_nonsecure_entry)]
-#[cmse_nonsecure_entry]
-//~^ ERROR: attribute should be applied to a function definition
-struct XEmpty2;
-//~^ NOTE: not a function definition

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/issue-83475.stderr

@@ -1,11 +0,0 @@
-error: attribute should be applied to a function definition
-  --> $DIR/issue-83475.rs:6:1
-   |
-LL | #[cmse_nonsecure_entry]
-   | ^^^^^^^^^^^^^^^^^^^^^^^
-LL |
-LL | struct XEmpty2;
-   | --------------- not a function definition
-
-error: aborting due to 1 previous error
-

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/params-on-registers.rs

@@ -3,14 +3,14 @@
 //@ needs-llvm-components: arm
 #![feature(cmse_nonsecure_entry, no_core, lang_items)]
 #![no_core]
-#[lang="sized"]
+#![crate_type = "lib"]
-trait Sized { }
+#[lang = "sized"]
-#[lang="copy"]
+trait Sized {}
-trait Copy { }
+#[lang = "copy"]
+trait Copy {}
 impl Copy for u32 {}
 
 #[no_mangle]
-#[cmse_nonsecure_entry]
+pub extern "C-cmse-nonsecure-entry" fn entry_function(_: u32, _: u32, _: u32, d: u32) -> u32 {
-pub extern "C" fn entry_function(_: u32, _: u32, _: u32, d: u32) -> u32 {
     d
 }

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/params-on-stack.rs

@@ -3,14 +3,19 @@
 //@ needs-llvm-components: arm
 #![feature(cmse_nonsecure_entry, no_core, lang_items)]
 #![no_core]
-#[lang="sized"]
+#[lang = "sized"]
-trait Sized { }
+trait Sized {}
-#[lang="copy"]
+#[lang = "copy"]
-trait Copy { }
+trait Copy {}
 impl Copy for u32 {}
 
 #[no_mangle]
-#[cmse_nonsecure_entry]
+pub extern "C-cmse-nonsecure-entry" fn entry_function(
-pub extern "C" fn entry_function(_: u32, _: u32, _: u32, _: u32, e: u32) -> u32 {
+    _: u32,
+    _: u32,
+    _: u32,
+    _: u32,
+    e: u32,
+) -> u32 {
     e
 }

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/trustzone-only.rs

@@ -2,8 +2,8 @@
 #![feature(cmse_nonsecure_entry)]
 
 #[no_mangle]
-#[cmse_nonsecure_entry] //~ ERROR [E0775]
+pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
-pub extern "C" fn entry_function(input: u32) -> u32 {
+    //~^ ERROR [E0570]
     input + 6
 }
 

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/trustzone-only.stderr

@@ -1,9 +1,9 @@
-error[E0775]: `#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension
+error[E0570]: `"C-cmse-nonsecure-entry"` is not a supported ABI for the current target
   --> $DIR/trustzone-only.rs:5:1
    |
-LL | #[cmse_nonsecure_entry]
+LL | pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
-   | ^^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0775`.
+For more information about this error, try `rustc --explain E0570`.

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/wrong-abi.rs

@@ -1,16 +0,0 @@
-//@ compile-flags: --target thumbv8m.main-none-eabi --crate-type lib
-//@ needs-llvm-components: arm
-#![feature(cmse_nonsecure_entry, no_core, lang_items)]
-#![no_core]
-#[lang = "sized"]
-trait Sized {}
-
-#[lang = "copy"]
-trait Copy {}
-
-#[no_mangle]
-#[cmse_nonsecure_entry]
-//~^ ERROR `#[cmse_nonsecure_entry]` requires C ABI [E0776]
-pub fn entry_function(_: u32, _: u32, _: u32, d: u32) -> u32 {
-    d
-}

tests/ui/cmse-nonsecure/cmse-nonsecure-entry/wrong-abi.stderr

@@ -1,9 +0,0 @@
-error[E0776]: `#[cmse_nonsecure_entry]` requires C ABI
-  --> $DIR/wrong-abi.rs:12:1
-   |
-LL | #[cmse_nonsecure_entry]
-   | ^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0776`.