Allow foreign exceptions to unwind through Rust code

3 files changed, 132 insertions, 0 deletions

diff --git a/src/test/run-make-fulldeps/foreign-exceptions/Makefile b/src/test/run-make-fulldeps/foreign-exceptions/Makefile
new file mode 100644
index 00000000000..fd15db9f151
--- /dev/null
+++ b/src/test/run-make-fulldeps/foreign-exceptions/Makefile
@@ -0,0 +1,10 @@
+-include ../tools.mk
+
+all: foo
+	$(call RUN,foo)
+
+foo: foo.rs $(call NATIVE_STATICLIB,foo)
+	$(RUSTC) $< -lfoo $(EXTRACXXFLAGS)
+
+$(TMPDIR)/libfoo.o: foo.cpp
+	$(call COMPILE_OBJ_CXX,$@,$<)
diff --git a/src/test/run-make-fulldeps/foreign-exceptions/foo.cpp b/src/test/run-make-fulldeps/foreign-exceptions/foo.cpp
new file mode 100644
index 00000000000..9a6fab49f49
--- /dev/null
+++ b/src/test/run-make-fulldeps/foreign-exceptions/foo.cpp
@@ -0,0 +1,59 @@
+#include <assert.h>
+#include <stddef.h>
+#include <stdio.h>
+
+void println(const char* s) {
+    puts(s);
+    fflush(stdout);
+}
+
+struct exception {};
+
+struct drop_check {
+    bool* ok;
+    ~drop_check() {
+        println("~drop_check");
+
+        if (ok)
+            *ok = true;
+    }
+};
+
+extern "C" {
+    void rust_catch_callback(void (*cb)(), bool* rust_ok);
+
+    static void callback() {
+        println("throwing C++ exception");
+        throw exception();
+    }
+
+    void throw_cxx_exception() {
+        bool rust_ok = false;
+        try {
+            rust_catch_callback(callback, &rust_ok);
+            assert(false && "unreachable");
+        } catch (exception e) {
+            println("caught C++ exception");
+            assert(rust_ok);
+            return;
+        }
+        assert(false && "did not catch thrown C++ exception");
+    }
+
+    void cxx_catch_callback(void (*cb)(), bool* cxx_ok) {
+        drop_check x;
+        x.ok = NULL;
+        try {
+            cb();
+        } catch (exception e) {
+            assert(false && "shouldn't be able to catch a rust panic");
+        } catch (...) {
+            println("caught foreign exception in catch (...)");
+            // Foreign exceptions are caught by catch (...). We only set the ok
+            // flag if we successfully caught the panic. The destructor of
+            // drop_check will then set the flag to true if it is executed.
+            x.ok = cxx_ok;
+            throw;
+        }
+    }
+}
diff --git a/src/test/run-make-fulldeps/foreign-exceptions/foo.rs b/src/test/run-make-fulldeps/foreign-exceptions/foo.rs
new file mode 100644
index 00000000000..83adf000d9e
--- /dev/null
+++ b/src/test/run-make-fulldeps/foreign-exceptions/foo.rs
@@ -0,0 +1,63 @@
+// Tests that C++ exceptions can unwind through Rust code, run destructors and
+// are ignored by catch_unwind. Also tests that Rust panics can unwind through
+// C++ code.
+
+#![feature(unwind_attributes)]
+
+use std::panic::{catch_unwind, AssertUnwindSafe};
+
+struct DropCheck<'a>(&'a mut bool);
+impl<'a> Drop for DropCheck<'a> {
+    fn drop(&mut self) {
+        println!("DropCheck::drop");
+        *self.0 = true;
+    }
+}
+
+extern "C" {
+    fn throw_cxx_exception();
+
+    #[unwind(allowed)]
+    fn cxx_catch_callback(cb: extern "C" fn(), ok: *mut bool);
+}
+
+#[no_mangle]
+#[unwind(allowed)]
+extern "C" fn rust_catch_callback(cb: extern "C" fn(), rust_ok: &mut bool) {
+    let _caught_unwind = catch_unwind(AssertUnwindSafe(|| {
+        let _drop = DropCheck(rust_ok);
+        cb();
+        unreachable!("should have unwound instead of returned");
+    }));
+    unreachable!("catch_unwind should not have caught foreign exception");
+}
+
+fn throw_rust_panic() {
+    #[unwind(allowed)]
+    extern "C" fn callback() {
+        println!("throwing rust panic");
+        panic!(1234i32);
+    }
+
+    let mut dropped = false;
+    let mut cxx_ok = false;
+    let caught_unwind = catch_unwind(AssertUnwindSafe(|| {
+        let _drop = DropCheck(&mut dropped);
+        unsafe {
+            cxx_catch_callback(callback, &mut cxx_ok);
+        }
+        unreachable!("should have unwound instead of returned");
+    }));
+    println!("caught rust panic");
+    assert!(dropped);
+    assert!(caught_unwind.is_err());
+    let panic_obj = caught_unwind.unwrap_err();
+    let panic_int = *panic_obj.downcast_ref::<i32>().unwrap();
+    assert_eq!(panic_int, 1234);
+    assert!(cxx_ok);
+}
+
+fn main() {
+    unsafe { throw_cxx_exception() };
+    throw_rust_panic();
+}