[SYCL] Test Level Zero static link flow (#716)

Add a test that traces the PI calls and the Level Zero driver calls,
and makes sure that the sequence of calls is consistent with the
"static linking" implementation.

Author: gmlueck

SYCL/KernelAndProgram/level-zero-static-link-flow.cpp

@@ -0,0 +1,52 @@
+// RUN: %clangxx -fsycl %s -o %t.out
+// RUN: %GPU_RUN_PLACEHOLDER SYCL_PI_TRACE=-1 ZE_DEBUG=1 %t.out 2>&1 | FileCheck %s
+// REQUIRES: level_zero
+//
+//==--- level-zero-static-link-flow.cpp.cpp - Check L0 static link flow --==//
+//
+// Run a simple program that uses online linking and verify that the sequence
+// of calls to the plugin and to the Level Zero driver are consistent with the
+// "static linking" implementation.
+//
+// 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
+//
+//===--------------------------------------------------------------===//
+
+// The key thing we check here is that the call to "zeModuleCreate" does not
+// happen from "piProgramCompile".  Instead, we expect it to be delayed and
+// called from "piProgramLink".
+//
+// CHECK: ---> piProgramCreate
+// CHECK: ---> piProgramCompile
+// CHECK-NOT: ZE ---> zeModuleCreate
+// CHECK: ---> piProgramLink
+// CHECK: ZE ---> zeModuleCreate
+
+#include <sycl/sycl.hpp>
+
+class MyKernel;
+
+void test() {
+  sycl::queue Queue;
+  sycl::context Context = Queue.get_context();
+
+  auto BundleInput =
+      sycl::get_kernel_bundle<MyKernel, sycl::bundle_state::input>(Context);
+  auto BundleObject = sycl::compile(BundleInput);
+  sycl::link(BundleObject);
+
+  // We need to define the kernel function, but we don't actually need to
+  // submit it to the device.
+  if (false) {
+    Queue.submit([&](sycl::handler &CGH) { CGH.single_task<MyKernel>([=] {}); })
+        .wait();
+  }
+}
+
+int main() {
+  test();
+
+  return 0;
+}