Using Set_inst_override_by_type() override uvm_object

UVM
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1

I have a requirement which need to override a uvm_object in uvm based test-bench.


`include "uvm_macros.svh"
import uvm_pkg::*;

class config_0 extends uvm_object;
  int number_of_axi = 0;
  `uvm_object_utils(config_0)

  function new(string name = "config_0");
    super.new(name);
    //`uvm_info("cfg","config-0 created",UVM_LOW)
  endfunction
endclass

class config_1 extends config_0;
  int number_of_axi = 1;
  `uvm_object_utils(config_1)
  function new(string name = "config_1");
    super.new(name);
    //`uvm_info("cfg","config-1 created",UVM_LOW)
  endfunction
endclass

class config_2 extends config_0;
  int number_of_axi = 2;
  `uvm_object_utils(config_2)
  function new(string name = "config_2");
    super.new(name);
    //`uvm_info("cfg","config-2 created",UVM_LOW)
  endfunction
endclass

class agent extends uvm_agent;
  config_0 cfg;
  `uvm_component_utils(agent)
  function new(string name, uvm_component parent);
    super.new(name, parent);
  endfunction : new
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    cfg = config_0::type_id::create("cfg",this);
    `uvm_info("cfg_value_print_in_agt",$sformatf("cfg.number_of_axi = %0d",cfg.number_of_axi),UVM_LOW)
  endfunction
endclass

class mem_model_env extends uvm_env;
  config_0 cfg;
  agent agt;
  `uvm_component_utils(mem_model_env)
  function new(string name, uvm_component parent);
    super.new(name, parent);
  endfunction : new
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    cfg = config_0::type_id::create("cfg");
    agt = agent::type_id::create("cfg",this);
    if(!uvm_config_db #(config_0)::get(this, "*", "cfg_i", cfg)) 
      `uvm_error("ERROR","not geting cfg")
    `uvm_info("cfg_value_print",$sformatf("cfg.number_of_axi = %0d",cfg.number_of_axi),UVM_LOW)
  endfunction : build_phase
endclass : mem_model_env
class top_env extends uvm_env;
  config_0 cfg0;
  config_1 cfg1;
  config_2 cfg2;
  mem_model_env env[3];
  uvm_factory factory;
  `uvm_component_utils(top_env)
  function new(string name = "top_env", uvm_component parent);
    super.new(name,parent);
    factory = uvm_factory::get();
    set_inst_override_by_type("env[0].cfg",config_0::get_type(),config_1::get_type());
    set_inst_override_by_type("env[1].cfg",config_0::get_type(),config_1::get_type());
    set_inst_override_by_type("env[2].cfg",config_0::get_type(),config_2::get_type());
  endfunction
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    factory = uvm_factory::get();
    cfg1 = config_1::type_id::create("cfg1");
    cfg2 = config_2::type_id::create("cfg2");
    uvm_config_db #(config_1)::set(this, "*.env[0]*", "cfg_i", cfg1);
    uvm_config_db #(config_1)::set(this, "*.env[1]*", "cfg_i", cfg1);  
    uvm_config_db #(config_2)::set(this, "*.env[2]*", "cfg_i", cfg2);  
    factory.print();
    foreach(env[i]) begin
      env[i] = mem_model_env::type_id::create($sformatf("env[%0d]",i),this);
    end
  endfunction: build_phase
endclass

class base_test extends uvm_test;
  top_env env;
  `uvm_component_utils(base_test)
  function new(string name, uvm_component parent);
    super.new(name, parent);
  endfunction
   virtual function void build_phase(uvm_phase phase);
     super.build_phase(phase);
     env = top_env::type_id::create("env",this);
   endfunction
endclass
module test;
  initial begin
    run_test("base_test");
  end
endmodule

When I follow above code I get 0 value in `uvm_info(“cfg_value_print”,$sformatf(“cfg.number_of_axi = %0d”,cfg.number_of_axi),UVM_LOW) (at mem_model_env build_phase). I want to get value from top_env which I set using config_db. If any one know to to do that please provide a solution for that.
Thanks.

2

In reply to Kashyap_14:

There are essentially 2 properties named ’ number_of_axi ’ within objects of class ’ config_1 ’ and ’ config_2 ’ .
SV says you can’t access extended class properties using base class handle .
As a result you observe value as 0 i.e value of property ’ number_of_axi ’ in base class .

A few notable issues with your code :

  1. For uvm_config_get to be successful the specialization should Match .You have set using specialization as config_1 ( twice ) and config_2 ( once ) . Whereas your get is done using specialization as config_0 . As a result your get fails thrice !!
  2. The 2nd argument to set is incorrect
  3. Instead of declaring property ’ number_of_axi ’ within extended class , simply re-assign it from extended class constructor.

You can check the following : edalink

Also please not that for future threads it’s easier for us to help if you could share an edalink of your working code .