Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

do not add prolog for variadic naked functions #123249

Merged
merged 1 commit into from
Apr 12, 2024
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 7 additions & 0 deletions compiler/rustc_codegen_ssa/src/mir/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ use crate::base;
use crate::traits::*;
use rustc_index::bit_set::BitSet;
use rustc_index::IndexVec;
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::mir;
use rustc_middle::mir::traversal;
use rustc_middle::mir::UnwindTerminateReason;
Expand Down Expand Up @@ -290,6 +291,12 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(

let mut num_untupled = None;

let codegen_fn_attrs = bx.tcx().codegen_fn_attrs(fx.instance.def_id());
let naked = codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED);
if naked {
return vec![];
}

let args = mir
.args_iter()
.enumerate()
Expand Down
19 changes: 19 additions & 0 deletions tests/codegen/cffi/c-variadic-naked.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
//@ needs-asm-support
//@ only-x86_64

// tests that `va_start` is not injected into naked functions

#![crate_type = "lib"]
#![feature(c_variadic)]
#![feature(naked_functions)]
#![no_std]

#[naked]
pub unsafe extern "C" fn c_variadic(_: usize, _: ...) {
// CHECK-NOT: va_start
// CHECK-NOT: alloca
core::arch::asm! {
"ret",
options(noreturn),
}
}
2 changes: 1 addition & 1 deletion tests/codegen/naked-fn/naked-functions.rs
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ pub unsafe extern "C" fn naked_empty() {
}

// CHECK: Function Attrs: naked
// CHECK-NEXT: define{{.*}}i{{[0-9]+}} @naked_with_args_and_return(i64 %a, i64 %b)
// CHECK-NEXT: define{{.*}}i{{[0-9]+}} @naked_with_args_and_return(i64 %0, i64 %1)
#[no_mangle]
#[naked]
pub unsafe extern "C" fn naked_with_args_and_return(a: isize, b: isize) -> isize {
Expand Down
Loading