Fix warnings about the `native` target-cpu

This fixes a regression from #53031 where specifying `-C target-cpu=native` is
printing a lot of warnings from LLVM about `native` being an unknown CPU. It
turns out that `native` is indeed an unknown CPU and we have to perform a
mapping to an actual CPU name, but this mapping is only performed in one
location rather than all locations we inform LLVM about the target CPU.

This commit centralizes the mapping of `native` to LLVM's value of the native
CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's
never `native`.

Closes #53322

1 files changed, 2 insertions, 1 deletions

diff --git a/src/librustc_codegen_llvm/attributes.rs b/src/librustc_codegen_llvm/attributes.rs
index 2b64642b766..c8a2b47e98d 100644
--- a/src/librustc_codegen_llvm/attributes.rs
+++ b/src/librustc_codegen_llvm/attributes.rs
@@ -124,7 +124,8 @@ pub fn llvm_target_features(sess: &Session) -> impl Iterator<Item = &str> {
 }
 
 pub fn apply_target_cpu_attr(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
-    let target_cpu = CString::new(cx.tcx.sess.target_cpu().to_string()).unwrap();
+    let cpu = llvm_util::target_cpu(cx.tcx.sess);
+    let target_cpu = CString::new(cpu).unwrap();
     llvm::AddFunctionAttrStringValue(
             llfn,
             llvm::AttributePlace::Function,