[Offload] Implement the remaining initial Offload API (#122106)

Implement the complete initial version of the Offload API, to the extent
that is usable for simple offloading programs. Tested with a basic SYCL
program.

As far as possible, these are simple wrappers over existing
functionality in the plugins.

* Allocating and freeing memory (host, device, shared).
* Creating a program 
* Creating a queue (wrapper over asynchronous stream resource)
* Enqueuing memcpy operations
* Enqueuing kernel executions
* Waiting on (optional) output events from the enqueue operations
* Waiting on a queue to finish

Objects created with the API have reference counting semantics to handle
their lifetime. They are created with an initial reference count of 1,
which can be incremented and decremented with retain and release
functions. They are freed when their reference count reaches 0. Platform
and device objects are not reference counted, as they are expected to
persist as long as the library is in use, and it's not meaningful for
users to create or destroy them.

Tests have been added to `offload.unittests`, including device code for
testing program and kernel related functionality.

The API should still be considered unstable and it's very likely we will
need to change the existing entry points.

5 files changed, 50 insertions, 72 deletions

diff --git a/offload/unittests/OffloadAPI/device/olGetDevice.cpp b/offload/unittests/OffloadAPI/device/olGetDevice.cpp
deleted file mode 100644
index 68d4682dd335..000000000000
--- a/offload/unittests/OffloadAPI/device/olGetDevice.cpp
+++ /dev/null
@@ -1,39 +0,0 @@
-//===------- Offload API tests - olGetDevice -------------------------===//
-//
-// 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 "../common/Fixtures.hpp"
-#include <OffloadAPI.h>
-#include <gtest/gtest.h>
-
-using olGetDeviceTest = offloadPlatformTest;
-
-TEST_F(olGetDeviceTest, Success) {
-  uint32_t Count = 0;
-  ASSERT_SUCCESS(olGetDeviceCount(Platform, &Count));
-  if (Count == 0)
-    GTEST_SKIP() << "No available devices on this platform.";
-
-  std::vector<ol_device_handle_t> Devices(Count);
-  ASSERT_SUCCESS(olGetDevice(Platform, Count, Devices.data()));
-  for (auto Device : Devices) {
-    ASSERT_NE(nullptr, Device);
-  }
-}
-
-TEST_F(olGetDeviceTest, SuccessSubsetOfDevices) {
-  uint32_t Count;
-  ASSERT_SUCCESS(olGetDeviceCount(Platform, &Count));
-  if (Count < 2)
-    GTEST_SKIP() << "Only one device is available on this platform.";
-
-  std::vector<ol_device_handle_t> Devices(Count - 1);
-  ASSERT_SUCCESS(olGetDevice(Platform, Count - 1, Devices.data()));
-  for (auto Device : Devices) {
-    ASSERT_NE(nullptr, Device);
-  }
-}
diff --git a/offload/unittests/OffloadAPI/device/olGetDeviceCount.cpp b/offload/unittests/OffloadAPI/device/olGetDeviceCount.cpp
deleted file mode 100644
index ef377d671bf6..000000000000
--- a/offload/unittests/OffloadAPI/device/olGetDeviceCount.cpp
+++ /dev/null
@@ -1,28 +0,0 @@
-//===------- Offload API tests - olGetDeviceCount --------------------===//
-//
-// 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 "../common/Fixtures.hpp"
-#include <OffloadAPI.h>
-#include <gtest/gtest.h>
-
-using olGetDeviceCountTest = offloadPlatformTest;
-
-TEST_F(olGetDeviceCountTest, Success) {
-  uint32_t Count = 0;
-  ASSERT_SUCCESS(olGetDeviceCount(Platform, &Count));
-}
-
-TEST_F(olGetDeviceCountTest, InvalidNullPlatform) {
-  uint32_t Count = 0;
-  ASSERT_ERROR(OL_ERRC_INVALID_NULL_HANDLE, olGetDeviceCount(nullptr, &Count));
-}
-
-TEST_F(olGetDeviceCountTest, InvalidNullPointer) {
-  ASSERT_ERROR(OL_ERRC_INVALID_NULL_POINTER,
-               olGetDeviceCount(Platform, nullptr));
-}
diff --git a/offload/unittests/OffloadAPI/device/olGetDeviceInfo.cpp b/offload/unittests/OffloadAPI/device/olGetDeviceInfo.cpp
index c936802fb1e4..f71f60a2c057 100644
--- a/offload/unittests/OffloadAPI/device/olGetDeviceInfo.cpp
+++ b/offload/unittests/OffloadAPI/device/olGetDeviceInfo.cpp
@@ -11,10 +11,10 @@
 #include <OffloadAPI.h>
 #include <gtest/gtest.h>
 
-struct olGetDeviceInfoTest : offloadDeviceTest,
+struct olGetDeviceInfoTest : OffloadDeviceTest,
                              ::testing::WithParamInterface<ol_device_info_t> {
 
-  void SetUp() override { RETURN_ON_FATAL_FAILURE(offloadDeviceTest::SetUp()); }
+  void SetUp() override { RETURN_ON_FATAL_FAILURE(OffloadDeviceTest::SetUp()); }
 };
 
 INSTANTIATE_TEST_SUITE_P(
@@ -37,7 +37,7 @@ TEST_P(olGetDeviceInfoTest, Success) {
   if (InfoType == OL_DEVICE_INFO_PLATFORM) {
     auto *ReturnedPlatform =
         reinterpret_cast<ol_platform_handle_t *>(InfoData.data());
-    ASSERT_EQ(Platform, *ReturnedPlatform);
+    ASSERT_NE(nullptr, *ReturnedPlatform);
   }
 }
 
diff --git a/offload/unittests/OffloadAPI/device/olGetDeviceInfoSize.cpp b/offload/unittests/OffloadAPI/device/olGetDeviceInfoSize.cpp
index 9e792d1c3e25..b4b5042dbfd8 100644
--- a/offload/unittests/OffloadAPI/device/olGetDeviceInfoSize.cpp
+++ b/offload/unittests/OffloadAPI/device/olGetDeviceInfoSize.cpp
@@ -12,10 +12,10 @@
 #include "olDeviceInfo.hpp"
 
 struct olGetDeviceInfoSizeTest
-    : offloadDeviceTest,
+    : OffloadDeviceTest,
       ::testing::WithParamInterface<ol_device_info_t> {
 
-  void SetUp() override { RETURN_ON_FATAL_FAILURE(offloadDeviceTest::SetUp()); }
+  void SetUp() override { RETURN_ON_FATAL_FAILURE(OffloadDeviceTest::SetUp()); }
 };
 
 // TODO: We could autogenerate the list of enum values
diff --git a/offload/unittests/OffloadAPI/device/olIterateDevices.cpp b/offload/unittests/OffloadAPI/device/olIterateDevices.cpp
new file mode 100644
index 000000000000..5bdbd17e9e97
--- /dev/null
+++ b/offload/unittests/OffloadAPI/device/olIterateDevices.cpp
@@ -0,0 +1,45 @@
+//===------- Offload API tests - olIterateDevices -------------------------===//
+//
+// 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 "../common/Fixtures.hpp"
+#include <OffloadAPI.h>
+#include <gtest/gtest.h>
+
+using olIterateDevicesTest = OffloadTest;
+
+TEST_F(olIterateDevicesTest, SuccessEmptyCallback) {
+  ASSERT_SUCCESS(olIterateDevices(
+      [](ol_device_handle_t, void *) { return false; }, nullptr));
+}
+
+TEST_F(olIterateDevicesTest, SuccessGetDevice) {
+  uint32_t DeviceCount = 0;
+  ol_device_handle_t Device = nullptr;
+
+  ASSERT_SUCCESS(olIterateDevices(
+      [](ol_device_handle_t, void *Data) {
+        auto Count = static_cast<uint32_t *>(Data);
+        *Count += 1;
+        return false;
+      },
+      &DeviceCount));
+
+  if (DeviceCount == 0) {
+    GTEST_SKIP() << "No available devices.";
+  }
+
+  ASSERT_SUCCESS(olIterateDevices(
+      [](ol_device_handle_t D, void *Data) {
+        auto DevicePtr = static_cast<ol_device_handle_t *>(Data);
+        *DevicePtr = D;
+        return true;
+      },
+      &Device));
+
+  ASSERT_NE(Device, nullptr);
+}