Extend assembly test to nail down behavior

compiler/rustc_codegen_cranelift/src/abi/mod.rs

@@ -61,6 +61,9 @@ pub(crate) fn conv_to_call_conv(sess: &Session, c: Conv, default_call_conv: Call
         Conv::CCmseNonSecureCall => {
             sess.dcx().fatal("C-cmse-nonsecure-call call conv is not yet implemented");
         }
+        Conv::CCmseNonSecureEntry => {
+            sess.dcx().fatal("C-cmse-nonsecure-entry call conv is not yet implemented");
+        }
 
         Conv::Msp430Intr | Conv::PtxKernel | Conv::AvrInterrupt | Conv::AvrNonBlockingInterrupt => {
             unreachable!("tried to use {c:?} call conv which only exists on an unsupported target");

compiler/rustc_codegen_llvm/src/abi.rs

@@ -407,6 +407,9 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
         if let Conv::RiscvInterrupt { kind } = self.conv {
             func_attrs.push(llvm::CreateAttrStringValue(cx.llcx, "interrupt", kind.as_str()));
         }
+        if let Conv::CCmseNonSecureEntry = self.conv {
+            func_attrs.push(llvm::CreateAttrString(cx.llcx, "cmse_nonsecure_entry"))
+        }
         attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &{ func_attrs });
 
         let mut i = 0;
@@ -606,9 +609,11 @@ impl<'tcx> AbiBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
 impl From<Conv> for llvm::CallConv {
     fn from(conv: Conv) -> Self {
         match conv {
-            Conv::C | Conv::Rust | Conv::CCmseNonSecureCall | Conv::RiscvInterrupt { .. } => {
-                llvm::CCallConv
-            }
+            Conv::C
+            | Conv::Rust
+            | Conv::CCmseNonSecureCall
+            | Conv::CCmseNonSecureEntry
+            | Conv::RiscvInterrupt { .. } => llvm::CCallConv,
             Conv::Cold => llvm::ColdCallConv,
             Conv::PreserveMost => llvm::PreserveMost,
             Conv::PreserveAll => llvm::PreserveAll,

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -475,9 +475,6 @@ pub fn from_fn_attrs<'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" fn entry_function() {}
+pub extern "C-cmse-nonsecure-entry" 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

@@ -678,3 +678,4 @@ E0798: 0798,
 //  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`

compiler/rustc_feature/src/builtin_attrs.rs

@@ -549,10 +549,6 @@ 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

@@ -394,7 +394,7 @@ 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

@@ -111,9 +111,7 @@ 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
-        /// function as an entry function from Non-Secure code.
-        const CMSE_NONSECURE_ENTRY      = 1 << 13;
+        // (Bit 13 was used for `#[cmse_nonsecure_entry]`, but is now unused.)
         // (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_middle/src/ty/layout.rs

@@ -1213,6 +1213,7 @@ pub fn fn_can_unwind(tcx: TyCtxt<'_>, fn_def_id: Option<DefId>, abi: SpecAbi) ->
         | RiscvInterruptM
         | RiscvInterruptS
         | CCmseNonSecureCall
+        | CCmseNonSecureEntry
         | Unadjusted => false,
         Rust | RustCall | RustCold | RustIntrinsic => {
             tcx.sess.panic_strategy() == PanicStrategy::Unwind

compiler/rustc_passes/src/check_attr.rs

@@ -182,9 +182,6 @@ 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),
@@ -555,27 +552,6 @@ 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;

compiler/rustc_smir/src/rustc_internal/internal.rs

@@ -467,6 +467,7 @@ impl RustcInternal for Abi {
             Abi::AvrInterrupt => rustc_target::spec::abi::Abi::AvrInterrupt,
             Abi::AvrNonBlockingInterrupt => rustc_target::spec::abi::Abi::AvrNonBlockingInterrupt,
             Abi::CCmseNonSecureCall => rustc_target::spec::abi::Abi::CCmseNonSecureCall,
+            Abi::CCmseNonSecureEntry => rustc_target::spec::abi::Abi::CCmseNonSecureEntry,
             Abi::System { unwind } => rustc_target::spec::abi::Abi::System { unwind },
             Abi::RustIntrinsic => rustc_target::spec::abi::Abi::RustIntrinsic,
             Abi::RustCall => rustc_target::spec::abi::Abi::RustCall,

compiler/rustc_smir/src/rustc_smir/convert/abi.rs

@@ -105,6 +105,7 @@ impl<'tcx> Stable<'tcx> for rustc_target::abi::call::Conv {
             Conv::PreserveAll => CallConvention::PreserveAll,
             Conv::ArmAapcs => CallConvention::ArmAapcs,
             Conv::CCmseNonSecureCall => CallConvention::CCmseNonSecureCall,
+            Conv::CCmseNonSecureEntry => CallConvention::CCmseNonSecureEntry,
             Conv::Msp430Intr => CallConvention::Msp430Intr,
             Conv::PtxKernel => CallConvention::PtxKernel,
             Conv::X86Fastcall => CallConvention::X86Fastcall,

compiler/rustc_smir/src/rustc_smir/convert/ty.rs

@@ -909,6 +909,7 @@ impl<'tcx> Stable<'tcx> for rustc_target::spec::abi::Abi {
             abi::Abi::AvrInterrupt => Abi::AvrInterrupt,
             abi::Abi::AvrNonBlockingInterrupt => Abi::AvrNonBlockingInterrupt,
             abi::Abi::CCmseNonSecureCall => Abi::CCmseNonSecureCall,
+            abi::Abi::CCmseNonSecureEntry => Abi::CCmseNonSecureEntry,
             abi::Abi::System { unwind } => Abi::System { unwind },
             abi::Abi::RustIntrinsic => Abi::RustIntrinsic,
             abi::Abi::RustCall => Abi::RustCall,

compiler/rustc_target/src/abi/call/mod.rs

@@ -751,6 +751,7 @@ pub enum Conv {
     // Target-specific calling conventions.
     ArmAapcs,
     CCmseNonSecureCall,
+    CCmseNonSecureEntry,
 
     Msp430Intr,
 
@@ -945,6 +946,7 @@ impl FromStr for Conv {
             "RustCold" => Ok(Conv::Rust),
             "ArmAapcs" => Ok(Conv::ArmAapcs),
             "CCmseNonSecureCall" => Ok(Conv::CCmseNonSecureCall),
+            "CCmseNonSecureEntry" => Ok(Conv::CCmseNonSecureEntry),
             "Msp430Intr" => Ok(Conv::Msp430Intr),
             "PtxKernel" => Ok(Conv::PtxKernel),
             "X86Fastcall" => Ok(Conv::X86Fastcall),

compiler/rustc_target/src/json.rs

@@ -103,6 +103,7 @@ impl ToJson for crate::abi::call::Conv {
             Self::PreserveAll => "PreserveAll",
             Self::ArmAapcs => "ArmAapcs",
             Self::CCmseNonSecureCall => "CCmseNonSecureCall",
+            Self::CCmseNonSecureEntry => "CCmseNonSecureEntry",
             Self::Msp430Intr => "Msp430Intr",
             Self::PtxKernel => "PtxKernel",
             Self::X86Fastcall => "X86Fastcall",

compiler/rustc_target/src/spec/abi/mod.rs

@@ -48,6 +48,7 @@ pub enum Abi {
     AvrInterrupt,
     AvrNonBlockingInterrupt,
     CCmseNonSecureCall,
+    CCmseNonSecureEntry,
     System {
         unwind: bool,
     },
@@ -122,6 +123,7 @@ const AbiDatas: &[AbiData] = &[
     AbiData { abi: Abi::AvrInterrupt, name: "avr-interrupt" },
     AbiData { abi: Abi::AvrNonBlockingInterrupt, name: "avr-non-blocking-interrupt" },
     AbiData { abi: Abi::CCmseNonSecureCall, name: "C-cmse-nonsecure-call" },
+    AbiData { abi: Abi::CCmseNonSecureEntry, name: "C-cmse-nonsecure-entry" },
     AbiData { abi: Abi::System { unwind: false }, name: "system" },
     AbiData { abi: Abi::System { unwind: true }, name: "system-unwind" },
     AbiData { abi: Abi::RustIntrinsic, name: "rust-intrinsic" },
@@ -242,6 +244,10 @@ pub fn is_stable(name: &str) -> Result<(), AbiDisabled> {
             feature: sym::abi_c_cmse_nonsecure_call,
             explain: "C-cmse-nonsecure-call ABI is experimental and subject to change",
         }),
+        "C-cmse-nonsecure-entry" => Err(AbiDisabled::Unstable {
+            feature: sym::cmse_nonsecure_entry,
+            explain: "C-cmse-nonsecure-entry ABI is experimental and subject to change",
+        }),
         _ => Err(AbiDisabled::Unrecognized),
     }
 }
@@ -284,15 +290,16 @@ impl Abi {
             AvrInterrupt => 23,
             AvrNonBlockingInterrupt => 24,
             CCmseNonSecureCall => 25,
+            CCmseNonSecureEntry => 26,
             // Cross-platform ABIs
-            System { unwind: false } => 26,
-            System { unwind: true } => 27,
-            RustIntrinsic => 28,
-            RustCall => 29,
-            Unadjusted => 30,
-            RustCold => 31,
-            RiscvInterruptM => 32,
-            RiscvInterruptS => 33,
+            System { unwind: false } => 27,
+            System { unwind: true } => 28,
+            RustIntrinsic => 29,
+            RustCall => 30,
+            Unadjusted => 31,
+            RustCold => 32,
+            RiscvInterruptM => 33,
+            RiscvInterruptS => 34,
         };
         debug_assert!(
             AbiDatas

compiler/rustc_target/src/spec/mod.rs

@@ -2672,7 +2672,10 @@ impl Target {
             }
             X86Interrupt => ["x86", "x86_64"].contains(&&self.arch[..]),
             Aapcs { .. } => "arm" == self.arch,
-            CCmseNonSecureCall => ["arm", "aarch64"].contains(&&self.arch[..]),
+            CCmseNonSecureCall | CCmseNonSecureEntry => {
+                ["thumbv8m.main-none-eabi", "thumbv8m.main-none-eabihf", "thumbv8m.base-none-eabi"]
+                    .contains(&&self.llvm_target[..])
+            }
             Win64 { .. } | SysV64 { .. } => self.arch == "x86_64",
             PtxKernel => self.arch == "nvptx64",
             Msp430Interrupt => self.arch == "msp430",

compiler/rustc_ty_utils/src/abi.rs

@@ -345,6 +345,7 @@ fn conv_from_spec_abi(tcx: TyCtxt<'_>, abi: SpecAbi, c_variadic: bool) -> Conv {
         SysV64 { .. } => Conv::X86_64SysV,
         Aapcs { .. } => Conv::ArmAapcs,
         CCmseNonSecureCall => Conv::CCmseNonSecureCall,
+        CCmseNonSecureEntry => Conv::CCmseNonSecureEntry,
         PtxKernel => Conv::PtxKernel,
         Msp430Interrupt => Conv::Msp430Intr,
         X86Interrupt => Conv::X86Intr,

compiler/stable_mir/src/abi.rs

@@ -433,6 +433,7 @@ pub enum CallConvention {
     // Target-specific calling conventions.
     ArmAapcs,
     CCmseNonSecureCall,
+    CCmseNonSecureEntry,
 
     Msp430Intr,
 

compiler/stable_mir/src/ty.rs

@@ -1062,6 +1062,7 @@ pub enum Abi {
     AvrInterrupt,
     AvrNonBlockingInterrupt,
     CCmseNonSecureCall,
+    CCmseNonSecureEntry,
     System { unwind: bool },
     RustIntrinsic,
     RustCall,

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" fn entry_function(input: u32) -> u32 {
+pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
     input + 6
 }
 ```

src/tools/rust-analyzer/crates/hir-ty/src/lib.rs

@@ -374,6 +374,7 @@ pub enum FnAbi {
     AvrNonBlockingInterrupt,
     C,
     CCmseNonsecureCall,
+    CCmseNonsecureEntry,
     CDecl,
     CDeclUnwind,
     CUnwind,
@@ -431,6 +432,7 @@ impl FnAbi {
             s if *s == sym::avr_dash_interrupt => FnAbi::AvrInterrupt,
             s if *s == sym::avr_dash_non_dash_blocking_dash_interrupt => FnAbi::AvrNonBlockingInterrupt,
             s if *s == sym::C_dash_cmse_dash_nonsecure_dash_call => FnAbi::CCmseNonsecureCall,
+            s if *s == sym::C_dash_cmse_dash_nonsecure_dash_entry => FnAbi::CCmseNonsecureEntry,
             s if *s == sym::C_dash_unwind => FnAbi::CUnwind,
             s if *s == sym::C => FnAbi::C,
             s if *s == sym::cdecl_dash_unwind => FnAbi::CDeclUnwind,
@@ -474,6 +476,7 @@ impl FnAbi {
             FnAbi::AvrNonBlockingInterrupt => "avr-non-blocking-interrupt",
             FnAbi::C => "C",
             FnAbi::CCmseNonsecureCall => "C-cmse-nonsecure-call",
+            FnAbi::CCmseNonsecureEntry => "C-cmse-nonsecure-entry",
             FnAbi::CDecl => "C-decl",
             FnAbi::CDeclUnwind => "cdecl-unwind",
             FnAbi::CUnwind => "C-unwind",

src/tools/rust-analyzer/crates/ide-completion/src/completions/extern_abi.rs

@@ -32,6 +32,7 @@ const SUPPORTED_CALLING_CONVENTIONS: &[&str] = &[
     "riscv-interrupt-m",
     "riscv-interrupt-s",
     "C-cmse-nonsecure-call",
+    "C-cmse-nonsecure-entry",
     "wasm",
     "system",
     "system-unwind",

src/tools/rust-analyzer/crates/intern/src/symbol/symbols.rs

@@ -94,6 +94,7 @@ define_symbols! {
     avr_dash_interrupt = "avr-interrupt",
     avr_dash_non_dash_blocking_dash_interrupt = "avr-non-blocking-interrupt",
     C_dash_cmse_dash_nonsecure_dash_call = "C-cmse-nonsecure-call",
+    C_dash_cmse_dash_nonsecure_dash_entry = "C-cmse-nonsecure-entry",
     C_dash_unwind = "C-unwind",
     cdecl_dash_unwind = "cdecl-unwind",
     fastcall_dash_unwind = "fastcall-unwind",

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