Add test

tests/run-make/staticlib-broken-bitcode/rmake.rs

@@ -0,0 +1,23 @@
+// Regression test for https://github.com/rust-lang/rust/issues/128955#issuecomment-2657811196
+// which checks that rustc can read an archive containing LLVM bitcode with a
+// newer version from the one rustc links against.
+use run_make_support::{llvm_ar, path, rfs, rustc, static_lib_name};
+
+fn main() {
+    rfs::create_dir("archive");
+
+    let mut bitcode = b"BC\xC0\xDE".to_vec();
+    bitcode.extend(std::iter::repeat(b'a').take(50));
+    rfs::write("archive/invalid_bitcode.o", &bitcode);
+
+    llvm_ar()
+        .obj_to_thin_ar()
+        .output_input(
+            path("archive").join(static_lib_name("thin_archive")),
+            "archive/invalid_bitcode.o",
+        )
+        .run();
+
+    // Build an rlib which includes the members of this thin archive
+    rustc().input("rust_lib.rs").library_search_path("archive").run();
+}

tests/run-make/staticlib-broken-bitcode/rust_lib.rs

@@ -0,0 +1,6 @@
+#![crate_type = "rlib"]
+
+#[link(name = "thin_archive", kind = "static")]
+extern "C" {
+    pub fn simple_fn();
+}