UVM factory registration

UVM
,
1

I found people always use the phrase “Factory Registration” to refer to uvm_component_utils and uvm_object_utils, however when unwrapping the macro, it’s just some static variables and functions like below, it’s not interacting with factory,

typedef uvm_component_registry #(my_component, “my_component”) type_id;

static function type_id get_type();
return type_id::get();
endfunction

…

I understand type_id is a proxy class containing create() function talking with factory for class override stuffs, also inside type_id::create() it will call type_id::get() which will register this type_id to the factory hash m_type_names and I suppose this is the only time registration happens.

However someone must trigger type_id::create to do the factory registration as we always do in the UVM testbench right? Why I’m seeing no one is triggering type_id::create() but still that class type is registered into factory, like below example:
uvm factory registration question - EDA Playground
In this example, foo_component is not even newed or created, how come it’s in the factory registered class type list??
Type Name

base_test
foo_component
snps_uvm_reg_bank_group
snps_uvm_reg_map

This question has been in my mind for a long time, really appreciate it if someone can answer it.

2

In reply to yangshh08:

We do not register objects with the factory, we are registering objects and components, i.e. classes. Classes will be considered as types.

3

In reply to chr_sue:

Thanks chr_sue, but I think you’re not answering my questions.
Basically the question is below:

  1. Why do people call uvm_component_utils and uvm_object_utils factory registrations but the macro is actually just some variables and function definitions, not registering to the factory at all.
  2. Why we don’t call type_id::create to new the object at all but it’s still shown in the factory registered type list and appears to have been registered to the factory. Click the link I provided and run you’ll know what I’m saying
4

In reply to yangshh08:

What do you mean it is not registering and what do you believe the macro should o? I do not know all the details, but this is not of interest for me, because I do not want to extend/enhance the UVM Base Class Library. I’m a user and it works perfectly. This is what counts.

5

In reply to chr_sue:

True, but that part is within my curiosity.
@dave_59 Hi Dave, could you throw out some inspirations?

6

In reply to yangshh08:

See my articles and video for more information on how factory registration works:

http://go.mentor.com/mcem
http://go.mentor.com/yin-and-yang
http://go.mentor.com/SV-OOP

7

In reply to dave_59:

Thanks Dave, I got the idea.
I didn’t know when we typedef a class it will create those static variables, during the creation of those static variables it will call get() then call f.register().