[SYCL] Test error handling undefined device symbol (#712)

Add a test for the case when a kernel references an undefined symbol.
We expect an exception at kernel submission time with a message
telling the name of the undefined symbol.

Author: gmlueck

SYCL/KernelAndProgram/undefined-symbol.cpp

@@ -0,0 +1,56 @@
+// XFAIL: cuda || hip
+// UNSUPPORTED: host
+// RUN: %clangxx -fsycl %s -o %t.out
+// RUN: %CPU_RUN_PLACEHOLDER %t.out
+// RUN: %GPU_RUN_PLACEHOLDER %t.out
+// RUN: %ACC_RUN_PLACEHOLDER %t.out
+//
+//==--- undefined-symbol.cpp - Error handling for undefined device symbol --==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===--------------------------------------------------------------===//
+
+#include <sycl/sycl.hpp>
+SYCL_EXTERNAL
+void symbol_that_does_not_exist();
+
+void test() {
+  sycl::queue Queue;
+
+  auto Kernel = []() {
+#ifdef __SYCL_DEVICE_ONLY__
+    // This is not guaranteed by the SYCL specification, but DPC++ currently
+    // does not diagnose an error at compilation/link time if a kernel
+    // references an undefined symbol from within code that is protected by
+    // __SYCL_DEVICE_ONLY__.  As a result, this error is delayed and diagnosed
+    // at runtime when the kernel is submitted to a device.
+    //
+    // This test is "unsupported" on the host device because the kernel does
+    // not actually contain an undefined reference in that case.
+    symbol_that_does_not_exist();
+#endif // __SYCL_DEVICE_ONLY__
+  };
+
+  try {
+    Queue.submit(
+        [&](sycl::handler &CGH) { CGH.single_task<class SingleTask>(Kernel); });
+    assert(false && "Expected error submitting kernel");
+  } catch (const sycl::exception &e) {
+    assert((e.code() == sycl::errc::build) && "Wrong error code");
+
+    // Error message should mention name of undefined symbol.
+    std::string Msg(e.what());
+    assert(Msg.find("symbol_that_does_not_exist") != std::string::npos);
+  } catch (...) {
+    assert(false && "Expected sycl::exception");
+  }
+}
+
+int main() {
+  test();
+
+  return 0;
+}