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Allow (but don't require) #[unsafe(naked)] so that compiler-builtins can upgrade to it #139797

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Merged
merged 1 commit into from
Apr 15, 2025
+34 −28
Merged

Allow (but don't require) #[unsafe(naked)] so that compiler-builtins can upgrade to it #139797

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6 changes: 6 additions & 0 deletions compiler/rustc_parse/src/validate_attr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -194,6 +194,12 @@ pub fn check_attribute_safety(psess: &ParseSess, safety: AttributeSafety, attr:
}
}
} else if let Safety::Unsafe(unsafe_span) = attr_item.unsafety {
// Allow (but don't require) `#[unsafe(naked)]` so that compiler-builtins can upgrade to it.
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Could this be a FIXME?

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sure, I've made it link back to this PR, which should provide sufficient context.

Also, Ideally this should only be there for a couple of days, the PRs to remove it again are already more or less done, so it's just a matter of getting this change into a nightly build, updating compiler-builtins, and then making #[naked] a proper unsafe attribute.

// FIXME(#139797): remove this special case when compiler-builtins has upgraded.
if attr.has_name(sym::naked) {
return;
}

psess.dcx().emit_err(errors::InvalidAttrUnsafe {
span: unsafe_span,
name: attr_item.path.clone(),
Expand Down
56 changes: 28 additions & 28 deletions tests/ui/asm/naked-functions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@

use std::arch::{asm, naked_asm};

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn inline_asm_macro() {
asm!("", options(raw));
//~^ERROR the `asm!` macro is not allowed in naked functions
Expand All @@ -20,7 +20,7 @@ pub struct P {
y: u16,
}

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn patterns(
mut a: u32,
//~^ ERROR patterns not allowed in naked function parameters
Expand All @@ -34,27 +34,27 @@ pub unsafe extern "C" fn patterns(
naked_asm!("")
}

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn inc(a: u32) -> u32 {
//~^ ERROR naked functions must contain a single `naked_asm!` invocation
a + 1
//~^ ERROR referencing function parameters is not allowed in naked functions
}

#[naked]
#[unsafe(naked)]
#[allow(asm_sub_register)]
pub unsafe extern "C" fn inc_asm(a: u32) -> u32 {
naked_asm!("/* {0} */", in(reg) a)
//~^ ERROR the `in` operand cannot be used with `naked_asm!`
}

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn inc_closure(a: u32) -> u32 {
//~^ ERROR naked functions must contain a single `naked_asm!` invocation
(|| a + 1)()
}

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn unsupported_operands() {
//~^ ERROR naked functions must contain a single `naked_asm!` invocation
let mut a = 0usize;
Expand All @@ -76,12 +76,12 @@ pub unsafe extern "C" fn unsupported_operands() {
);
}

#[naked]
#[unsafe(naked)]
pub extern "C" fn missing_assembly() {
//~^ ERROR naked functions must contain a single `naked_asm!` invocation
}

#[naked]
#[unsafe(naked)]
pub extern "C" fn too_many_asm_blocks() {
//~^ ERROR naked functions must contain a single `naked_asm!` invocation
unsafe {
Expand All @@ -92,7 +92,7 @@ pub extern "C" fn too_many_asm_blocks() {
}

pub fn outer(x: u32) -> extern "C" fn(usize) -> usize {
#[naked]
#[unsafe(naked)]
pub extern "C" fn inner(y: usize) -> usize {
//~^ ERROR naked functions must contain a single `naked_asm!` invocation
*&y
Expand All @@ -101,35 +101,35 @@ pub fn outer(x: u32) -> extern "C" fn(usize) -> usize {
inner
}

#[naked]
#[unsafe(naked)]
unsafe extern "C" fn invalid_options() {
naked_asm!("", options(nomem, preserves_flags));
//~^ ERROR the `nomem` option cannot be used with `naked_asm!`
//~| ERROR the `preserves_flags` option cannot be used with `naked_asm!`
}

#[naked]
#[unsafe(naked)]
unsafe extern "C" fn invalid_options_continued() {
naked_asm!("", options(readonly, nostack), options(pure));
//~^ ERROR the `readonly` option cannot be used with `naked_asm!`
//~| ERROR the `nostack` option cannot be used with `naked_asm!`
//~| ERROR the `pure` option cannot be used with `naked_asm!`
}

#[naked]
#[unsafe(naked)]
unsafe extern "C" fn invalid_may_unwind() {
naked_asm!("", options(may_unwind));
//~^ ERROR the `may_unwind` option cannot be used with `naked_asm!`
}

#[naked]
#[unsafe(naked)]
pub extern "C" fn valid_a<T>() -> T {
unsafe {
naked_asm!("");
}
}

#[naked]
#[unsafe(naked)]
pub extern "C" fn valid_b() {
unsafe {
{
Expand All @@ -140,40 +140,40 @@ pub extern "C" fn valid_b() {
}
}

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn valid_c() {
naked_asm!("");
}

#[cfg(target_arch = "x86_64")]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn valid_att_syntax() {
naked_asm!("", options(att_syntax));
}

#[naked]
#[naked]
#[unsafe(naked)]
#[unsafe(naked)]
pub unsafe extern "C" fn allow_compile_error(a: u32) -> u32 {
compile_error!("this is a user specified error")
//~^ ERROR this is a user specified error
}

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn allow_compile_error_and_asm(a: u32) -> u32 {
compile_error!("this is a user specified error");
//~^ ERROR this is a user specified error
naked_asm!("")
}

#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn invalid_asm_syntax(a: u32) -> u32 {
naked_asm!(invalid_syntax)
//~^ ERROR asm template must be a string literal
}

#[cfg(target_arch = "x86_64")]
#[cfg_attr(target_pointer_width = "64", no_mangle)]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_cfg_attributes() {
naked_asm!("", options(att_syntax));
}
Expand All @@ -182,20 +182,20 @@ pub unsafe extern "C" fn compatible_cfg_attributes() {
#[warn(dead_code)]
#[deny(dead_code)]
#[forbid(dead_code)]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_diagnostic_attributes() {
naked_asm!("", options(raw));
}

#[deprecated = "test"]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_deprecated_attributes() {
naked_asm!("", options(raw));
}

#[cfg(target_arch = "x86_64")]
#[must_use]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_must_use_attributes() -> u64 {
naked_asm!(
"
Expand All @@ -207,13 +207,13 @@ pub unsafe extern "C" fn compatible_must_use_attributes() -> u64 {

#[export_name = "exported_function_name"]
#[link_section = ".custom_section"]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_ffi_attributes_1() {
naked_asm!("", options(raw));
}

#[cold]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_codegen_attributes() {
naked_asm!("", options(raw));
}
Expand All @@ -222,13 +222,13 @@ pub unsafe extern "C" fn compatible_codegen_attributes() {
/// a doc comment
// a normal comment
#[doc(alias = "ADocAlias")]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_doc_attributes() {
naked_asm!("", options(raw));
}

#[linkage = "external"]
#[naked]
#[unsafe(naked)]
pub unsafe extern "C" fn compatible_linkage() {
naked_asm!("", options(raw));
}
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