Compile program in the nightly CI

Author: antoyo

.github/workflows/nightly_rustc.yml

@@ -65,3 +65,20 @@ jobs:
         cd rust
         # TODO: add --host=${{ matrix.arch.host_target }} if needed (should not be since it's in the toml config file)
         ./x build --stage 2 --config ../rustc_codegen_gcc/tests/bootstraps/bootstrap.${{ matrix.arch.host_target }}.toml
+
+    - name: Link toolchain
+      run: rustup toolchain link my-toolchain build/${{ matrix.arch.host_target }}/stage2
+
+    - name: Compile test program
+      run: |
+        cd rustc_codegen_gcc/tests/hello-world
+        cargo +my-toolchain build
+        cargo +my-toolchain run > hello_world_stdout
+
+        expected_output="40"
+        test $(cat hello_world_stdout) == $expected_output || (echo "Output differs. Actual output: $(cat hello_world_stdout)"; exit 1)
+
+        objcopy --dump-section .comment=comment target/debug/hello_world
+        grep --text "^.rustc version .* with libgccjit" comment
+        grep --text 'libgccjit' comment
+        grep --text 'GCC: ' comment