The object at dereference depth 1 is being used before it was constructed/allocated. Please make sure that the object is allocated before using it

UVM
,
24

I posted my toplevel model. You can there is a clock(clk).

calc_driver.sv
include "calc_sequence.sv" class calc_driver extends uvm_driver #(calc_trans); uvm_component_utils(calc_driver)

virtual calc_if dut_ifc1;

function new(string name, uvm_component parent);
super.new(name,parent);
endfunction: new

function void build_phase(uvm_phase phase);
super.build_phase(phase);
if(!uvm_config_db#(virtual calc_if)::get(this,“”,“dut_vif”, dut_ifc1))
`uvm_fatal(“NOVIF”,{“virtual interface must be set for: “,get_full_name(),”.dut_ifc”});
$display(“driver”);
endfunction: build_phase

task run_phase(uvm_phase phase);

repeat(300)

begin
calc_trans tx;
seq_item_port.get_next_item(tx);

   dut_ifc1.a <= tx.a;
   dut_ifc1.b <= tx.b;
   dut_ifc1.opcode <= tx.opcode;
   
 seq_item_port.item_done();
end

endtask: run_phase
endclass: calc_driver

calc_sequence.sv
class calc_sequence extends uvm_sequence#(calc_trans);
`uvm_object_utils(calc_sequence)

function new(string name = “calc_sequence”);
super.new(name);
endfunction: new

task body();
	calc_trans req;
$display("calc_seq");
	
repeat(300) begin
	req = calc_trans::type_id::create("req");

start_item(req);
	assert(req.randomize());
	finish_item(req);
$display("a = ", req.a);
$display("b = ", req.b);
$display("opcode = ", req.opcode);
	end
endtask: body

endclass: calc_sequence

calc_test.sv
class calc_test extends uvm_test;

`uvm_component_utils(calc_test)

calc_env env;
calc_sequence calc_seq;

function new(string name = “calc_test”,uvm_component parent=null);
super.new(name,parent);
endfunction : new

virtual function void build_phase(uvm_phase phase);
super.build_phase(phase);
env = calc_env::type_id::create(“env”, this);
calc_seq = calc_sequence::type_id::create(“calc_seq”, this);
endfunction : build_phase

task run_phase(uvm_phase phase);
phase.raise_objection(this);
calc_seq.start(env.calc_agent_h.calc_sequencer_h);
phase.drop_objection(this);
endtask : run_phase

endclass : calc_test