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Rollup merge of #146144 - heiher:entry-func-features, r=petrochenkov

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compiler: Apply target features to the entry function

Fixes rust-lang/rust#146143
This commit is contained in:
León Orell Valerian Liehr 2025-09-05 22:47:20 +02:00 • committed by GitHub
commit 1c2d264eb0
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GPG key ID: B5690EEEBB952194
2 changed files with 22 additions and 10 deletions
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22
compiler/rustc_codegen_llvm/src/attributes.rs
View file

@ -296,6 +296,19 @@ pub(crate) fn tune_cpu_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribu
.map(|tune_cpu| llvm::CreateAttrStringValue(cx.llcx, "tune-cpu", tune_cpu))
}
/// Get the `target-features` LLVM attribute.
pub(crate) fn target_features_attr<'ll>(
cx: &CodegenCx<'ll, '_>,
function_features: Vec<String>,
) -> Option<&'ll Attribute> {
let global_features = cx.tcx.global_backend_features(()).iter().map(String::as_str);
let function_features = function_features.iter().map(String::as_str);
let target_features =
global_features.chain(function_features).intersperse(",").collect::<String>();
(!target_features.is_empty())
.then(|| llvm::CreateAttrStringValue(cx.llcx, "target-features", &target_features))
}
/// Get the `NonLazyBind` LLVM attribute,
/// if the codegen options allow skipping the PLT.
pub(crate) fn non_lazy_bind_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribute> {
@ -523,14 +536,7 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
}
}
let global_features = cx.tcx.global_backend_features(()).iter().map(|s| s.as_str());
let function_features = function_features.iter().map(|s| s.as_str());
let target_features: String =
global_features.chain(function_features).intersperse(",").collect();
if !target_features.is_empty() {
to_add.push(llvm::CreateAttrStringValue(cx.llcx, "target-features", &target_features));
}
to_add.extend(target_features_attr(cx, function_features));
attributes::apply_to_llfn(llfn, Function, &to_add);
}

10
compiler/rustc_codegen_llvm/src/context.rs
View file

@ -853,7 +853,7 @@ impl<'ll, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
fn declare_c_main(&self, fn_type: Self::Type) -> Option<Self::Function> {
let entry_name = self.sess().target.entry_name.as_ref();
if self.get_declared_value(entry_name).is_none() {
Some(self.declare_entry_fn(
let llfn = self.declare_entry_fn(
entry_name,
llvm::CallConv::from_conv(
self.sess().target.entry_abi,
@ -861,7 +861,13 @@ impl<'ll, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
),
llvm::UnnamedAddr::Global,
fn_type,
))
);
attributes::apply_to_llfn(
llfn,
llvm::AttributePlace::Function,
attributes::target_features_attr(self, vec![]).as_slice(),
);
Some(llfn)
} else {
// If the symbol already exists, it is an error: for example, the user wrote
// #[no_mangle] extern "C" fn main(..) {..}