rewrite cross-lang-lto-upstream-rlibs to rmake

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -1,6 +1,5 @@
 run-make/branch-protection-check-IBT/Makefile
 run-make/cat-and-grep-sanity-check/Makefile
-run-make/cross-lang-lto-upstream-rlibs/Makefile
 run-make/dep-info-doesnt-run-much/Makefile
 run-make/dep-info-spaces/Makefile
 run-make/dep-info/Makefile

tests/run-make/cross-lang-lto-upstream-rlibs/Makefile

@@ -0,0 +1,61 @@
+// When using the flag -C linker-plugin-lto, static libraries could lose their upstream object
+// files during compilation. This bug was fixed in #53031, and this test compiles a staticlib
+// dependent on upstream, checking that the upstream object file still exists after no LTO and
+// thin LTO.
+// See https://github.com/rust-lang/rust/pull/53031
+
+// ignore windows due to libLLVM being present in PATH and the PATH and library path being the same
+// (so fixing it is harder). See #57765 for context
+//FIXME(Oneirical): ignore-windows
+
+use run_make_support::{
+    cwd, has_extension, has_prefix, has_suffix, llvm_ar, rfs, rustc, shallow_find_files,
+    static_lib_name,
+};
+
+fn main() {
+    // The test starts with no LTO enabled.
+    rustc().input("upstream.rs").arg("-Clinker-plugin-lto").codegen_units(1).run();
+    rustc()
+        .input("staticlib.rs")
+        .arg("-Clinker-plugin-lto")
+        .codegen_units(1)
+        .output(static_lib_name("staticlib"))
+        .run();
+    llvm_ar().arg("x").arg(static_lib_name("staticlib")).run();
+    // Ensure the upstream object file was included.
+    assert_eq!(
+        shallow_find_files(cwd(), |path| {
+            has_prefix(path, "upstream.") && has_suffix(path, ".rcgu.o")
+        })
+        .len(),
+        1
+    );
+    // Remove all output files that are not source Rust code for cleanup.
+    for file in shallow_find_files(cwd(), |path| !has_extension(path, "rs")) {
+        rfs::remove_file(file)
+    }
+
+    // Check it again, with Thin LTO.
+    rustc()
+        .input("upstream.rs")
+        .arg("-Clinker-plugin-lto")
+        .codegen_units(1)
+        .arg("-Clto=thin")
+        .run();
+    rustc()
+        .input("staticlib.rs")
+        .arg("-Clinker-plugin-lto")
+        .codegen_units(1)
+        .arg("-Clto=thin")
+        .output(static_lib_name("staticlib"))
+        .run();
+    llvm_ar().arg("x").arg(static_lib_name("staticlib")).run();
+    assert_eq!(
+        shallow_find_files(cwd(), |path| {
+            has_prefix(path, "upstream.") && has_suffix(path, ".rcgu.o")
+        })
+        .len(),
+        1
+    );
+}