1 files changed, 78 insertions, 0 deletions
diff --git a/tensorflow/core/kernels/host_constant_op.cc b/tensorflow/core/kernels/host_constant_op.cc
new file mode 100644
index 0000000000..d08a7c9bd2
--- /dev/null
+++ b/tensorflow/core/kernels/host_constant_op.cc
@@ -0,0 +1,78 @@
+/* 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.
+==============================================================================*/
+
+#include "tensorflow/core/kernels/host_constant_op.h"
+
+#include "tensorflow/core/framework/allocator.h"
+#include "tensorflow/core/framework/op_kernel.h"
+#include "tensorflow/core/framework/types.h"
+#include "tensorflow/core/lib/core/status.h"
+#include "tensorflow/core/platform/logging.h"
+#include "tensorflow/core/platform/macros.h"
+
+namespace tensorflow {
+
+_HostConstantOp::_HostConstantOp(OpKernelConstruction* ctx)
+    : OpKernel(ctx), tensor_(ctx->output_type(0)) {
+  const TensorProto* proto = nullptr;
+  AllocatorAttributes alloc_attr;
+  alloc_attr.set_on_host(true);
+  OP_REQUIRES_OK(ctx, ctx->GetAttr("value", &proto));
+  OP_REQUIRES_OK(
+      ctx, ctx->device()->MakeTensorFromProto(*proto, alloc_attr, &tensor_));
+  OP_REQUIRES(
+      ctx, ctx->output_type(0) == tensor_.dtype(),
+      errors::InvalidArgument("Type mismatch between value (",
+                              DataTypeString(tensor_.dtype()), ") and dtype (",
+                              DataTypeString(ctx->output_type(0)), ")"));
+}
+
+void _HostConstantOp::Compute(OpKernelContext* ctx) {
+  ctx->set_output(0, tensor_);
+}
+
+#if GOOGLE_CUDA
+// A special GPU kernel for int32.
+// TODO(b/25387198): Also enable int32 in device memory. This kernel
+// registration requires all int32 inputs and outputs to be in host memory.
+REGISTER_KERNEL_BUILDER(Name("Const")
+                            .Device(DEVICE_GPU)
+                            .HostMemory("output")
+                            .TypeConstraint<int32>("dtype"),
+                        _HostConstantOp);
+#endif
+
+#ifdef TENSORFLOW_USE_SYCL
+REGISTER_KERNEL_BUILDER(Name("Const")
+                            .Device(DEVICE_SYCL)
+                            .HostMemory("output")
+                            .TypeConstraint<int32>("dtype"),
+                        _HostConstantOp);
+#endif  // TENSORFLOW_USE_SYCL
+
+// HostConst: forced to generate output on the host.
+// Only used in tests; no op is registered for this kernel
+// externally (i.e., in array_ops.cc)
+REGISTER_KERNEL_BUILDER(Name("HostConst").Device(DEVICE_CPU), _HostConstantOp);
+REGISTER_KERNEL_BUILDER(
+    Name("HostConst").Device(DEVICE_GPU).HostMemory("output"), _HostConstantOp);
+#ifdef TENSORFLOW_USE_SYCL
+REGISTER_KERNEL_BUILDER(
+    Name("HostConst").Device(DEVICE_SYCL).HostMemory("output"),
+    _HostConstantOp);
+#endif  // TENSORFLOW_USE_SYCL
+
+}  // end namespace tensorflow
+