[Intel MKL] Static code analysis tool fixes

- mkl_cpu_allocator.h: disallowing copy constructor and assignement operator; returning nullptr from non-void functions even though they generate Unimplemented Status code
- mkl_graph_util.h: making kTensorOrdering const because it never gets changed anyway
- mkl_layout_pass.cc: adding checks for nullptr before dereferencing

2 files changed, 4 insertions, 1 deletions

diff --git a/tensorflow/core/graph/mkl_graph_util.h b/tensorflow/core/graph/mkl_graph_util.h
index 333bf761b0..bab1df87a4 100644
--- a/tensorflow/core/graph/mkl_graph_util.h
+++ b/tensorflow/core/graph/mkl_graph_util.h
@@ -41,7 +41,7 @@ namespace tensorflow {
 typedef enum { TENSORS_INTERLEAVED, TENSORS_CONTIGUOUS } MklTfTensorOrdering;
 // NOTE: Currently, we use contiguous ordering. If you change this, then you
 // would need to change Mkl op definitions in nn_ops.cc.
-static MklTfTensorOrdering kTensorOrdering = TENSORS_CONTIGUOUS;
+static const MklTfTensorOrdering kTensorOrdering = TENSORS_CONTIGUOUS;
 
 // Get index of MetaData tensor from index 'n' of Data tensor.
 inline int DataIndexToMetaDataIndex(int n, int total_tensors) {
diff --git a/tensorflow/core/graph/mkl_layout_pass.cc b/tensorflow/core/graph/mkl_layout_pass.cc
index 5683944e46..82a3a31e79 100644
--- a/tensorflow/core/graph/mkl_layout_pass.cc
+++ b/tensorflow/core/graph/mkl_layout_pass.cc
@@ -1042,6 +1042,7 @@ void MklLayoutRewritePass::GetDummyMklTensorNode(std::unique_ptr<Graph>* g,
                                                       // device of the original
                                                       // node.
                   .Finalize(&**g, out));
+  CHECK_NOTNULL(*out); // Make sure we got a valid object before using it
 
   // If number of inputs to the original node is > 0, then we add
   // control dependency between 1st input (index 0) of the original node and
@@ -1335,6 +1336,7 @@ void MklLayoutRewritePass::GetDummyWorkspaceTensorNode(
                                                       // device of the original
                                                       // node.
                   .Finalize(&**g, out));
+  CHECK_NOTNULL(*out); // Make sure we got a valid object before using it
 
   // If number of inputs to the original node is > 0, then we add
   // control dependency between 1st input (index 0) of the original node and
@@ -3177,6 +3179,7 @@ void MklLayoutRewritePass::GetDummyMklTensorNode(std::unique_ptr<Graph>* g,
                                                       // device of the original
                                                       // node.
                   .Finalize(&**g, out));
+  CHECK_NOTNULL(*out); // Make sure we got a valid object before using it
 
   // If number of inputs to the original node is > 0, then we add
   // control dependency between 1st input (index 0) of the original node and