rewrite compiler-rt-works-on-mingw to rmake

src/tools/run-make-support/src/external_deps/cc.rs

@@ -15,6 +15,12 @@ pub fn cc() -> Cc {
     Cc::new()
 }
 
+/// Construct a new platform-specific CXX compiler invocation.
+#[track_caller]
+pub fn cxx() -> Cc {
+    Cc::new_cxx()
+}
+
 /// A platform-specific C compiler invocation builder. The specific C compiler used is
 /// passed down from compiletest.
 #[derive(Debug)]
@@ -44,6 +50,21 @@ impl Cc {
         Self { cmd }
     }
 
+    /// Construct a new platform-specific CXX compiler invocation.
+    #[track_caller]
+    pub fn new_cxx() -> Self {
+        let compiler = env_var("CXX");
+
+        let mut cmd = Command::new(compiler);
+
+        let default_cflags = env_var("CXX_DEFAULT_FLAGS");
+        for flag in default_cflags.split(char::is_whitespace) {
+            cmd.arg(flag);
+        }
+
+        Self { cmd }
+    }
+
     /// Specify path of the input file.
     pub fn input<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
         self.cmd.arg(path.as_ref());

src/tools/run-make-support/src/lib.rs

@@ -44,7 +44,7 @@ pub use external_deps::{c_build, cc, clang, htmldocck, llvm, python, rustc, rust
 
 // These rely on external dependencies.
 pub use c_build::build_native_static_lib;
-pub use cc::{cc, extra_c_flags, extra_cxx_flags, Cc};
+pub use cc::{cc, cxx, extra_c_flags, extra_cxx_flags, Cc};
 pub use clang::{clang, Clang};
 pub use htmldocck::htmldocck;
 pub use llvm::{

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -4,7 +4,6 @@ run-make/c-dynamic-rlib/Makefile
 run-make/c-unwind-abi-catch-lib-panic/Makefile
 run-make/cat-and-grep-sanity-check/Makefile
 run-make/cdylib-dylib-linkage/Makefile
-run-make/compiler-rt-works-on-mingw/Makefile
 run-make/cross-lang-lto-clang/Makefile
 run-make/cross-lang-lto-pgo-smoketest/Makefile
 run-make/cross-lang-lto-upstream-rlibs/Makefile

tests/run-make/compiler-rt-works-on-mingw/rmake.rs

@@ -0,0 +1,15 @@
+// `compiler-rt` ("runtime") is a suite of LLVM features compatible with rustc.
+// After building it was enabled on Windows-gnu in #29874, this test checks
+// that compilation and execution with it are successful.
+// See https://github.com/rust-lang/rust/pull/29478
+
+//@ only-windows-gnu
+
+use run_make_support::{cxx, is_msvc, llvm_ar, run, rustc, static_lib_name};
+
+fn main() {
+    cxx().input("foo.cpp").arg("-c").out_exe("foo.o").run();
+    llvm_ar().obj_to_ar().output_input(static_lib_name("foo"), "foo.o").run();
+    rustc().input("foo.rs").arg("-lfoo").arg("-lstdc++").run();
+    run("foo");
+}