New XLA API to launch a program.

1. Propose a new API with ability to do input/output.
2. Start to enable ABSL in TF's codebase.

PiperOrigin-RevId: 210783617

1 files changed, 70 insertions, 0 deletions

diff --git a/tensorflow/compiler/xla/service/maybe_owning_device_memory.h b/tensorflow/compiler/xla/service/maybe_owning_device_memory.h
new file mode 100644
index 0000000000..82e7f1183c
--- /dev/null
+++ b/tensorflow/compiler/xla/service/maybe_owning_device_memory.h
@@ -0,0 +1,70 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#ifndef TENSORFLOW_COMPILER_XLA_SERVICE_MAYBE_OWNING_DEVICE_MEMORY_H_
+#define TENSORFLOW_COMPILER_XLA_SERVICE_MAYBE_OWNING_DEVICE_MEMORY_H_
+
+#include "absl/types/optional.h"
+#include "absl/types/variant.h"
+#include "tensorflow/compiler/xla/service/device_memory_allocator.h"
+#include "tensorflow/compiler/xla/service/owning_device_memory.h"
+
+namespace xla {
+
+// MaybeOwningDeviceMemory represents either an owned or unowned device memory.
+// Like std::variant<OwningDeviceMemory, DeviceMemory>. When the object goes
+// output of scope, it will free the underlying memory if it owns it.
+class MaybeOwningDeviceMemory {
+ public:
+  MaybeOwningDeviceMemory() = default;
+  explicit MaybeOwningDeviceMemory(OwningDeviceMemory owned)
+      : mem_(std::move(owned)) {}
+  explicit MaybeOwningDeviceMemory(se::DeviceMemoryBase unowned)
+      : mem_(unowned) {}
+  MaybeOwningDeviceMemory(MaybeOwningDeviceMemory&&) = default;
+  ~MaybeOwningDeviceMemory() = default;
+
+  MaybeOwningDeviceMemory& operator=(se::DeviceMemoryBase unowned) {
+    mem_ = unowned;
+    return *this;
+  }
+
+  MaybeOwningDeviceMemory& operator=(OwningDeviceMemory owned) {
+    mem_ = std::move(owned);
+    return *this;
+  }
+
+  MaybeOwningDeviceMemory& operator=(MaybeOwningDeviceMemory&&) = default;
+
+  // Fetches the underlying DeviceMemoryBase from a MaybeOwningDeviceMemory. The
+  // caller of this function is *not* responsible for freeing the memory.
+  se::DeviceMemoryBase AsDeviceMemoryBase();
+
+  // Release the OwningDeviceMemory without freeing it, and moves the ownership
+  // of the memory buffer from the object to the caller.
+  //
+  // A nullopt is returned if the HasOwnership() == false;
+  absl::optional<OwningDeviceMemory> Release();
+
+  // Returns true if the device_memory has ownership over underlying memory.
+  bool HasOwnership() const;
+
+ private:
+  absl::variant<OwningDeviceMemory, se::DeviceMemoryBase> mem_;
+};
+
+}  // namespace xla
+
+#endif  // TENSORFLOW_COMPILER_XLA_SERVICE_MAYBE_OWNING_DEVICE_MEMORY_H_