rethrow_current_exception

Summary: [Folly] `rethrow_current_exception`, a `-fno-exceptions` compatibility wrapper for `throw;`.

Reviewed By: ispeters

Differential Revision: D21656269

fbshipit-source-id: 8f37fe71c6255162b8f05268cae04ac5927013d7

folly/lang/Exception.h

@@ -237,4 +237,17 @@ FOLLY_ERASE_TRYCATCH auto catch_exception(Try&& t, Catch&& c, CatchA&&... a) ->
 #endif
 }
 
+/// rethrow_current_exception
+///
+/// Equivalent to:
+///
+///   throw;
+[[noreturn]] FOLLY_ERASE void rethrow_current_exception() {
+#if FOLLY_HAS_EXCEPTIONS
+  throw;
+#else
+  std::terminate();
+#endif
+}
+
 } // namespace folly

folly/lang/test/ExceptionTest.cpp

@@ -115,3 +115,15 @@ TEST_F(ExceptionTest, catch_exception) {
   EXPECT_EQ(4, folly::catch_exception(thrower(3), returner(4)));
   EXPECT_EQ(3, folly::catch_exception<int>(thrower(3), identity));
 }
+
+TEST_F(ExceptionTest, rethrow_current_exception) {
+  EXPECT_THROW(
+      folly::invoke_noreturn_cold([] {
+        try {
+          throw std::runtime_error("bad");
+        } catch (...) {
+          folly::rethrow_current_exception();
+        }
+      }),
+      std::runtime_error);
+}