Static Code Analysis result Update (#2624)

BUG="static code analysis result update"

Build test was done with the command below
  make -f tensorflow/lite/micro/tools/make/Makefile test

There will be an additional pull request later related to static code analysis

tensorflow/lite/micro/micro_allocation_info.h

@@ -129,7 +129,8 @@ class AllocationInfoBuilder {
 
   const tflite::Model* model_ = nullptr;
   INonPersistentBufferAllocator* non_persistent_allocator_ = nullptr;
-  GraphAllocationInfo info_;
+  GraphAllocationInfo info_ =
+      {};  // Prevents problems caused by accessing uninitialized memory.
   int allocation_scope_count_ = 0;
 };
 

tensorflow/lite/micro/micro_allocator.h

@@ -322,7 +322,9 @@ class MicroAllocator {
   IPersistentBufferAllocator* persistent_buffer_allocator_;
 
   // Allocator used to allocate persistent builtin data.
-  TfLiteBridgeBuiltinDataAllocator* builtin_data_allocator_;
+  TfLiteBridgeBuiltinDataAllocator* builtin_data_allocator_ =
+      nullptr;  // Initialized as nullptr to prevent any possible issues related
+                // to accessing uninitialized memory.
 
   // Activation buffer memory planner.
   MicroMemoryPlanner* memory_planner_;

tensorflow/lite/micro/micro_interpreter_graph.h

@@ -106,7 +106,9 @@ class MicroInterpreterGraph : public MicroGraph {
   int current_subgraph_index_;
   uint32_t current_operator_index_;
   MicroResourceVariables* resource_variables_;
-  const flatbuffers::Vector<flatbuffers::Offset<SubGraph>>* subgraphs_;
+  const flatbuffers::Vector<flatbuffers::Offset<SubGraph>>* subgraphs_ =
+      nullptr;  // Initialized as nullptr to prevent any possible issues
+                // related to accessing uninitialized memory.
 
   TF_LITE_REMOVE_VIRTUAL_DELETE
 };

tensorflow/lite/micro/micro_time.h

@@ -27,8 +27,11 @@ uint32_t ticks_per_second();
 uint32_t GetCurrentTimeTicks();
 
 inline uint32_t TicksToMs(int32_t ticks) {
+  uint32_t _ticks_per_second = ticks_per_second();
+  _ticks_per_second =
+      _ticks_per_second > 0 ? _ticks_per_second : 1;  // zero divide prevention
   return static_cast<uint32_t>(1000.0f * static_cast<float>(ticks) /
-                               static_cast<float>(ticks_per_second()));
+                               static_cast<float>(_ticks_per_second));
 }
 
 }  // namespace tflite

tensorflow/lite/micro/recording_micro_allocator.cc

@@ -78,9 +78,14 @@ RecordedAllocation RecordingMicroAllocator::GetRecordedAllocation(
       return recorded_node_and_registration_array_data_;
     case RecordedAllocationType::kOpData:
       return recorded_op_data_;
+    // the function MicroPrintf was never reached outside the switch, because
+    // each case has a return. As the intention of the MicroPrintf is to be
+    // called when no matching case is found, a default case was added to
+    // contemplate an invalid allocation type
+    default:
+      MicroPrintf("Invalid allocation type supplied: %d", allocation_type);
+      return RecordedAllocation();
   }
-  MicroPrintf("Invalid allocation type supplied: %d", allocation_type);
-  return RecordedAllocation();
 }
 
 const RecordingSingleArenaBufferAllocator*