Does create() utilize string parameter 'Tname' of class uvm_*_registry

SystemVerilog
,
1

I was going through Source Code to understand Factory Registration .

Class uvm_component_registry ( uvm_object_registry ) has 2 parameters , type parameter T and string parameter Tname .

String Registration utilizes both parameters ::


 //  Within  class  uvm_component_registry  / uvm_object_registry
 
     typedef  uvm_component_registry  #( T , Tname )   this_type  ;   // [A] 

     local   static  this_type  me  =  get() ;   
 
     //  Within  static  function   get()  ::
          
          if ( me ==  null )  begin
            
               me  =  new() ;      
           factory.register( me ) ;   //  Factory  Registration  
         
           ....................

Factory Registration takes place via following 2 properties [ Associative Array ] ::


 protected  uvm_object_wrapper   m_type_names [ string ]  ;       //   Used  for  String  Registration   

 protected  bit  m_types [ uvm_object_wrapper ]  ;               //   Used  for   Type  Registration

Now during string registration ::


  
  //   Within  Factory  function  register  with  I/P  Argument  ::  uvm_object_wrapper  obj  ;  //  Base  type  handle  !!
 
       m_type_names[ obj.get_type_name() ]  =  obj  ; 

  //   When  create_component_by_name()  is  called  via  run_test()  ::  
         
         wrapper = m_type_names[requested_type_name];   //  **. 
  
  //  LHS  is  ::  uvm_object_wrapper   wrapper ;

So essentially string index utilizes the string Argument Tname , whereas RHS obj

( points to extended object of class uvm_*_registry class ) [b]utilizes both parameters ( Since it’s of type ‘this_type’ ( Refer [A] above ) )**

**Hence String - Registration uses both type parameter ‘T’ as well as String
parameter ‘Tname’ during String Registration .

 Therefore   function  create_component_by_name()  uses  both  type parameter  'T'  
 as  well  as  String  parameter  'Tname'**

[Q] What about create() function ( which uses Type - based Factory ) ?
create() function internally calls create_component_by_type() .
OR Is it independent of string parameter Tname ??

 I   observe  that  Type  Registration  is  done  via  function  register()  in  uvm_factory  :: 



//   Within  Factory  function  register  with  I/P  Argument  ::  uvm_object_wrapper  obj  ;  //  Base  type  handle  !!
 
       m_types[ obj ]  =  1  ;   //   obj  is  of  type  'this_type'

But unlike array m_type_names which is read back ( Refer [ B ] above )
to create appropriate component , m_types isn’t read anywhere in Code

2

In reply to TC_2017:

Trying to read and understand the UVM source code accelerates your aging process. I only read it if the code does not behave as it is supposed to be documented.

The associative array m_type_names is just an extra layer that maps string names to proxy (wrapper) object types. The factory create mechanism only deals with types, and the type of the object is parameterized into that proxy object; there is no need to look it up.