Use safe AttrValue to invoke TF_SetAttrValueProto.

Author: Oceania2018

src/TensorFlowNET.Core/Attributes/c_api.ops.cs

@@ -61,7 +61,7 @@ public partial class c_api
         public static extern void TF_SetAttrBool(IntPtr desc, string attr_name, bool value);
 
         [DllImport(TensorFlowLibName)]
-        public static extern void TF_SetAttrValueProto(IntPtr desc, string attr_name, IntPtr proto, uint proto_len, SafeStatusHandle status);
+        public static extern void TF_SetAttrValueProto(IntPtr desc, string attr_name, byte[] proto, int proto_len, SafeStatusHandle status);
 
         /// <summary>
         /// Set `num_dims` to -1 to represent "unknown rank".

src/TensorFlowNET.Core/Contexts/ContextSwitch.cs

@@ -33,5 +33,8 @@ public class ContextSwitch
         public Action EnterContextFn { get; set; }
 
         public string DeviceStack { get; set; }
+
+        public override string ToString()
+            => $"EagerMode: {EagerMode}, IsBuildingFunction: {IsBuildingFunction}";
     }
 }

src/TensorFlowNET.Core/Operations/Operation.cs

@@ -168,7 +168,7 @@ public Operation(NodeDef node_def, Graph g, Tensor[] inputs = null, TF_DataType[
             if (op_def == null)
                 op_def = g.GetOpDef(node_def.Op);
 
-            (_handle, OpDesc) = ops._create_c_op(g, node_def, inputs, control_input_ops.ToArray());
+            (_handle, OpDesc) = ops._create_c_op(g, node_def, inputs, control_input_ops.ToArray(), op_def);
             _is_stateful = op_def.IsStateful;
 
             // Initialize self._outputs.

src/TensorFlowNET.Core/ops.cs

@@ -190,13 +190,9 @@ public static (IntPtr, OperationDescription) _create_c_op(Graph graph, NodeDef n
                 // Add attrs
                 foreach (var attr in node_def.Attr)
                 {
-                    var bytes = attr.Value.ToByteArray(); //TODO: we can use attr.Value.WriteTo with a memory stream.
-                    var protoHandle = Marshal.AllocHGlobal(bytes.Length);
-                    Marshal.Copy(bytes, 0, protoHandle, bytes.Length);
-                    uint len = (uint)bytes.Length;
-                    c_api.TF_SetAttrValueProto(op_desc, attr.Key, protoHandle, proto_len: len, status: status.Handle);
+                    var bytes = attr.Value.ToByteArray();
+                    c_api.TF_SetAttrValueProto(op_desc, attr.Key, bytes, proto_len: bytes.Length, status: status.Handle);
                     status.Check(true);
-                    Marshal.FreeHGlobal(protoHandle);
                 }
 
                 var c_op = c_api.TF_FinishOperation(op_desc, status.Handle);