Auto merge of #126607 - Oneirical:the-testern-world, r=jieyouxu

Rewrite `separate-link`, `separate-link-fail` and `allocator-shim-circular-deps` `run-make` tests to `ui` or `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).

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -1,4 +1,3 @@
-run-make/allocator-shim-circular-deps/Makefile
 run-make/archive-duplicate-names/Makefile
 run-make/atomic-lock-free/Makefile
 run-make/branch-protection-check-IBT/Makefile
@@ -185,8 +184,6 @@ run-make/rustdoc-io-error/Makefile
 run-make/sanitizer-cdylib-link/Makefile
 run-make/sanitizer-dylib-link/Makefile
 run-make/sanitizer-staticlib-link/Makefile
-run-make/separate-link-fail/Makefile
-run-make/separate-link/Makefile
 run-make/sepcomp-cci-copies/Makefile
 run-make/sepcomp-inlining/Makefile
 run-make/sepcomp-separate/Makefile

tests/run-make/allocator-shim-circular-deps/rmake.rs

@@ -0,0 +1,16 @@
+// This test is designed to intentionally introduce a circular dependency scenario to check
+// that a specific compiler bug doesn't make a resurgence.
+// The bug in question arose when at least one crate
+// required a global allocator, and that crate was placed after
+// the one defining it in the linker order.
+// The generated symbols.o should not result in any linker errors.
+// See https://github.com/rust-lang/rust/issues/112715
+
+//@ ignore-cross-compile
+
+use run_make_support::{rust_lib_name, rustc};
+
+fn main() {
+    rustc().input("my_lib.rs").run();
+    rustc().input("main.rs").arg("--test").extern_("my_lib", rust_lib_name("my_lib")).run();
+}

tests/run-make/separate-link-fail/foo.rs

@@ -0,0 +1 @@
+fn main() {}

tests/run-make/separate-link-fail/rmake.rs

@@ -0,0 +1,15 @@
+// rustc usually wants Rust code as its input. The flag `link-only` is one
+// exception, where a .rlink file is instead requested. The compiler should
+// fail when the user is wrongly passing the original Rust code
+// instead of the generated .rlink file when this flag is on.
+// https://github.com/rust-lang/rust/issues/95297
+
+use run_make_support::rustc;
+
+fn main() {
+    rustc()
+        .arg("-Zlink-only")
+        .input("foo.rs")
+        .run_fail()
+        .assert_stderr_contains("The input does not look like a .rlink file");
+}

tests/run-make/separate-link/rmake.rs

@@ -0,0 +1,14 @@
+// The compiler flags no-link (and by extension, link-only) used to be broken
+// due to changes in encoding/decoding. This was patched, and this test checks
+// that these flags are not broken again, resulting in successful compilation.
+// See https://github.com/rust-lang/rust/issues/77857
+
+//@ ignore-cross-compile
+
+use run_make_support::{run, rustc};
+
+fn main() {
+    rustc().stdin(b"fn main(){}").arg("-Zno-link").arg("-").run();
+    rustc().arg("-Zlink-only").input("rust_out.rlink").run();
+    run("rust_out");
+}