src/hotspot/share/code/codeBlob.hpp

   const char*         _name;
   S390_ONLY(int       _ctable_offset;)
 
   CodeBlob(const char* name, CompilerType type, const CodeBlobLayout& layout, int frame_complete_offset, int frame_size, ImmutableOopMapSet* oop_maps, bool caller_must_gc_arguments);
   CodeBlob(const char* name, CompilerType type, const CodeBlobLayout& layout, CodeBuffer* cb, int frame_complete_offset, int frame_size, OopMapSet* oop_maps, bool caller_must_gc_arguments);
+
 public:
+  // Only used by unit test.
+  CodeBlob()
+    : _type(compiler_none) {}
+
   // Returns the space needed for CodeBlob
   static unsigned int allocation_size(CodeBuffer* cb, int header_size);
   static unsigned int align_code_offset(int offset);
 
   // Deletion