rewrite and rename issue-84395-lto-embed-bitcode to rmake

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -12,7 +12,6 @@ run-make/extern-fn-reachable/Makefile
 run-make/foreign-double-unwind/Makefile
 run-make/foreign-exceptions/Makefile
 run-make/issue-36710/Makefile
-run-make/issue-84395-lto-embed-bitcode/Makefile
 run-make/issue-88756-default-output/Makefile
 run-make/jobserver-error/Makefile
 run-make/libs-through-symlinks/Makefile

tests/run-make/incr-add-rust-src-component/rmake.rs

@@ -1,5 +1,5 @@
-// rust-lang/rust#70924: Test that if we add rust-src component in between two
-// incremental compiles, the compiler does not ICE on the second.
+// rust-lang/rust#70924: Test that if we add rust-src component in between
+// two incremental compiles, the compiler does not ICE on the second.
 // Remove the rust-src part of the sysroot for the *first* build.
 // Then put in a facsimile of the rust-src
 // component for the second build, in order to expose the ICE from issue #70924.

tests/run-make/issue-84395-lto-embed-bitcode/Makefile

@@ -0,0 +1,30 @@
+// This test checks that the embed bitcode in elf created with
+// lto-embed-bitcode=optimized is a valid llvm bitcode module.
+// Otherwise, the `test.bc` file will cause an error when
+// `llvm-dis` attempts to disassemble it.
+// See https://github.com/rust-lang/rust/issues/84395
+
+//@ needs-force-clang-based-tests
+// NOTE(#126180): This test only runs on `x86_64-gnu-debug`, because that CI job sets
+// RUSTBUILD_FORCE_CLANG_BASED_TESTS and only runs tests which contain "clang" in their
+// name.
+
+use run_make_support::llvm::llvm_bin_dir;
+use run_make_support::{cmd, env_var, rustc};
+
+fn main() {
+    rustc()
+        .input("test.rs")
+        .link_arg("-fuse-ld=lld")
+        .arg("linker-plugin-lto")
+        .linker(&env_var("CLANG"))
+        .link_arg("-Wl,--plugin-opt=-lto-embed-bitcode=optimized")
+        .arg("-Zemit-thin-lto=no")
+        .run();
+    cmd(llvm_bin_dir().join("objcopy"))
+        .arg("--dump-section")
+        .arg(".llvmbc=test.bc")
+        .arg("test")
+        .run();
+    cmd(llvm_bin_dir().join("llvm-dis")).arg("test.bc").run();
+}