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Rollup merge of rust-lang#130146 - folkertdev:bootstrap-naked-asm, r=…
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…Amanieu

bootstrap `naked_asm!` for `compiler-builtins`

tracking issue: rust-lang#90957
parent PR: rust-lang#128651

in this PR, `naked_asm!` is added as an alias for `asm!` with one difference: `options(noreturn)` is always enabled by `naked_asm!`. That makes it future-compatible for when `naked_asm!` starts disallowing `options(noreturn)` later.

The `naked_asm!` macro must be introduced first so that we can upgrade `compiler-builtins` to use it, and can then change the implementation of `naked_asm!` in rust-lang#128651

I've added some usages for `naked_asm!` in the tests, so we can be confident that it works, but I've left upgrading the whole test suite to the parent PR.

r? `@Amanieu`
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workingjubilee authored Sep 10, 2024
2 parents 0d63d03 + 0237899 commit 91a3cf1
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Showing 5 changed files with 60 additions and 6 deletions.
38 changes: 38 additions & 0 deletions compiler/rustc_builtin_macros/src/asm.rs
Original file line number Diff line number Diff line change
Expand Up @@ -812,6 +812,44 @@ pub(super) fn expand_asm<'cx>(
})
}

pub(super) fn expand_naked_asm<'cx>(
ecx: &'cx mut ExtCtxt<'_>,
sp: Span,
tts: TokenStream,
) -> MacroExpanderResult<'cx> {
ExpandResult::Ready(match parse_args(ecx, sp, tts, false) {
Ok(args) => {
let ExpandResult::Ready(mac) = expand_preparsed_asm(ecx, args) else {
return ExpandResult::Retry(());
};
let expr = match mac {
Ok(mut inline_asm) => {
// for future compatibility, we always set the NORETURN option.
//
// When we turn `asm!` into `naked_asm!` with this implementation, we can drop
// the `options(noreturn)`, which makes the upgrade smooth when `naked_asm!`
// starts disallowing the `noreturn` option in the future
inline_asm.options |= ast::InlineAsmOptions::NORETURN;

P(ast::Expr {
id: ast::DUMMY_NODE_ID,
kind: ast::ExprKind::InlineAsm(P(inline_asm)),
span: sp,
attrs: ast::AttrVec::new(),
tokens: None,
})
}
Err(guar) => DummyResult::raw_expr(sp, Some(guar)),
};
MacEager::expr(expr)
}
Err(err) => {
let guar = err.emit();
DummyResult::any(sp, guar)
}
})
}

pub(super) fn expand_global_asm<'cx>(
ecx: &'cx mut ExtCtxt<'_>,
sp: Span,
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1 change: 1 addition & 0 deletions compiler/rustc_builtin_macros/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -94,6 +94,7 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
line: source_util::expand_line,
log_syntax: log_syntax::expand_log_syntax,
module_path: source_util::expand_mod,
naked_asm: asm::expand_naked_asm,
option_env: env::expand_option_env,
pattern_type: pattern_type::expand,
std_panic: edition_panic::expand_panic,
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1 change: 1 addition & 0 deletions compiler/rustc_span/src/symbol.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1256,6 +1256,7 @@ symbols! {
mut_preserve_binding_mode_2024,
mut_ref,
naked,
naked_asm,
naked_functions,
name,
names,
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14 changes: 14 additions & 0 deletions library/core/src/arch.rs
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,20 @@ pub macro asm("assembly template", $(operands,)* $(options($(option),*))?) {
/* compiler built-in */
}

/// Inline assembly used in combination with `#[naked]` functions.
///
/// Refer to [Rust By Example] for a usage guide and the [reference] for
/// detailed information about the syntax and available options.
///
/// [Rust By Example]: https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html
/// [reference]: https://doc.rust-lang.org/nightly/reference/inline-assembly.html
#[unstable(feature = "naked_functions", issue = "90957")]
#[rustc_builtin_macro]
#[cfg(not(bootstrap))]
pub macro naked_asm("assembly template", $(operands,)* $(options($(option),*))?) {
/* compiler built-in */
}

/// Module-level inline assembly.
///
/// Refer to [Rust By Example] for a usage guide and the [reference] for
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12 changes: 6 additions & 6 deletions tests/ui/asm/naked-functions-inline.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,37 +2,37 @@
#![feature(naked_functions)]
#![crate_type = "lib"]

use std::arch::asm;
use std::arch::naked_asm;

#[naked]
pub unsafe extern "C" fn inline_none() {
asm!("", options(noreturn));
naked_asm!("");
}

#[naked]
#[inline]
//~^ ERROR [E0736]
pub unsafe extern "C" fn inline_hint() {
asm!("", options(noreturn));
naked_asm!("");
}

#[naked]
#[inline(always)]
//~^ ERROR [E0736]
pub unsafe extern "C" fn inline_always() {
asm!("", options(noreturn));
naked_asm!("");
}

#[naked]
#[inline(never)]
//~^ ERROR [E0736]
pub unsafe extern "C" fn inline_never() {
asm!("", options(noreturn));
naked_asm!("");
}

#[naked]
#[cfg_attr(all(), inline(never))]
//~^ ERROR [E0736]
pub unsafe extern "C" fn conditional_inline_never() {
asm!("", options(noreturn));
naked_asm!("");
}

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