override UVM phase?

[jleng]

I just wonder if it is possible to override a build phase from uvm_driver?  Seems there's only way is to override driver type/instance, but not phase.  

 

 

 

 

thanks,

 

Jennifer,

[tudor.timi]

I think you are a bit confused about overriding. If you want to override the default behavior of build_phase(...) which is a function, then you just declare your own implementation:

class my_driver extends uvm_driver #(my_item);
  // factory registration stuff
  
  function void build_phase(uvm_phase phase);
    // super.build_phase means calling the build_phase function
    // as it was defined in the base class (our case uvm_driver)
    super.build_phase(phase);

    // up to now our build_phase does the exact same thing that
    // it did in the base class
    
    // add your extra code here
    // - code that does more stuff that you need
  endfunction

Whenever you extend a class (create a subclass) and redefine a method, this means you are overriding the method (method means function or task). Method overrides control what object actually do. When you instantiate an object of type my_driver and call build_phase, then the implementation we have defined above will get executed.

 

Type and instance overrides are a different thing that applies to the factory. They control what types of objects actually get instantiated.

[David Black]

To reinforce Tudor's reply, you will need to "override" twice - once in the OO sense, and once in the factory sense:

1. derive a new driver class (assuming you are overriding an existing driver)

2. implement your new build_phase -- IMPORTANT: you will probably want to call super.build_phase from within your new implementation

3. set_type_override or set_instance_override in the test class (or possibly the environment) during the build_phase of that class