Auto merge of #128562 - Oneirical:no-contest-expected, r=<try>

Migrate `incr-add-rust-src-component` and `issue-84395-lto-embed-bitcode` `run-make` tests to rmake

Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).

In `incr-add-rust-src-component`, I directly modify the sysroot, unlike the original test which used a symlink. This is probably a very bad idea, but I want to see what happens.

try-job: x86_64-gnu-debug

Author: bors

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -7,8 +7,6 @@ run-make/dep-info-spaces/Makefile
 run-make/dep-info/Makefile
 run-make/emit-to-stdout/Makefile
 run-make/extern-fn-reachable/Makefile
-run-make/incr-add-rust-src-component/Makefile
-run-make/issue-84395-lto-embed-bitcode/Makefile
 run-make/jobserver-error/Makefile
 run-make/libs-through-symlinks/Makefile
 run-make/libtest-json/Makefile

tests/run-make/incr-add-rust-src-component/Makefile

@@ -0,0 +1,21 @@
+// 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.
+// See https://github.com/rust-lang/rust/pull/72952
+
+//FIXME(Oneirical): try on test-various and windows
+//FIXME(Oneirical): check that the direct edit of the sysroot is not messing things up
+
+use run_make_support::{path, rfs, rustc};
+
+fn main() {
+    let sysroot = rustc().print("sysroot").run().stdout_utf8();
+    let sysroot = sysroot.trim();
+    rfs::remove_dir_all(path(&sysroot).join("lib/rustlib/src/rust"));
+    rustc().arg("--sysroot").arg(&sysroot).incremental("incr").input("main.rs").run();
+    rfs::create_dir_all(path(&sysroot).join("lib/rustlib/src/rust/src/libstd"));
+    rfs::create_file(path(&sysroot).join("lib/rustlib/src/rust/src/libstd/lib.rs"));
+    rustc().arg("--sysroot").arg(&sysroot).incremental("incr").input("main.rs").run();
+}

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

@@ -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("-Clinker-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();
+}