Verification Engineer's Blog: Override in UVM using factory with Example

One of the main advantage of UVM is Creating each components using factory enables them to be overridden in different tests or environments without changing underlying code base.

uvm_factory provides four different methods to override particular instance or all instances of particular class.
set_inst_override_by_type
set_inst_override_by_name
set_type_override_by_type
set_type_override_by_name

Let's go through example of each one of above four ways.

set_inst_override_by_type
-------------------------------------------------------

	// set_inst_override_by_type
	`include "uvm.svh"
	import uvm_pkg::*;
	//--------------------uvm_component------------------------------
	class A extends uvm_agent;
	`uvm_component_utils(A)

	function new (string name="A", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A new"), UVM_LOW);
	endfunction : new

	virtual function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'A'"), UVM_LOW);
	endfunction : hello
	endclass : A

	class A_ovr extends A;
	`uvm_component_utils(A_ovr)

	function new (string name="A_ovr", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_ovr new"), UVM_LOW);
	endfunction : new

	function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : A_ovr

	//--------------------uvm_object------------------------------
	class B extends uvm_object;
	`uvm_object_utils(B)

	function new (string name="B");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B new"), UVM_LOW);
	endfunction : new

	virtual function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'B'"), UVM_LOW);
	endfunction : hello
	endclass : B

	class B_ovr extends B;
	`uvm_object_utils(B_ovr)

	function new (string name="B_ovr");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_ovr new"), UVM_LOW);
	endfunction : new

	function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : B_ovr

	class B_override extends B_ovr;
	`uvm_object_utils(B_override)

	function new (string name="B_override");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_override new"), UVM_LOW);
	endfunction : new

	function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_override'"), UVM_LOW);
	endfunction : hello
	endclass : B_override

	//--------------------env class--------------------
	class environment extends uvm_env;
	`uvm_component_utils(environment)
	A a1;
	B b1, b2;

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

	function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	// arguments of create method:
	// 1. string name = ""
	// 2. uvm_component parent = null
	// 3. string contxt = ""
	// The contxt argument, if supplied, supercedes the parent's context.
	a1 = A::type_id::create("a1", this);
	b1 = B::type_id::create("b1", , "path1");
	b2 = B::type_id::create("b2", , "path2");

	a1.hello(); // This will print from overridden class A_ovr
	b1.hello(); // This will print from overridden class B_ovr
	b2.hello(); // This will print from overridden class B_override
	endfunction : build_phase
	endclass : environment

	//-------------------test class--------------------------
	class test extends uvm_test;
	`uvm_component_utils(test)
	environment env;

	function new(string name = "test", uvm_component parent = null);
	super.new(name, parent);
	endfunction : new

	virtual function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	env = environment::type_id::create("env", this);
	`uvm_info(get_full_name, $sformatf("TEST set_inst_override_by_type"), UVM_LOW);

	factory.set_inst_override_by_type(A::get_type(), A_ovr::get_type(), {get_full_name, ".", "env.a1"}); // Working

	//factory.set_inst_override_by_type(B::get_type(), B_ovr::get_type(), {get_full_name, ".", "env.b1"}); // Not working
	factory.set_inst_override_by_type(B::get_type(), B_ovr::get_type(), "path1.b1"); // Working

	//factory.set_inst_override_by_type(B::get_type(), B_override::get_type(), {get_full_name, ".", "env.b2"}); // Not working
	factory.set_inst_override_by_type(B::get_type(), B_override::get_type(), "path2.b2"); // Working

	factory.print(); // This will print info about overridden classes.
	endfunction : build_phase
	endclass : test

	module top();
	initial begin
	run_test("test");
	end
	endmodule : top

view raw set_instance_override_by_type.sv hosted with ❤ by GitHub

-------------------------------------------------------

-------------------------------------------------------

	//Output:
	// UVM_INFO @ 0: reporter [RNTST] Running test test...
	// UVM_INFO top.sv(118) @ 0: uvm_test_top [uvm_test_top] TEST set_inst_override_by_type
	//
	// #### Factory Configuration (*)
	// Instance Overrides:
	// Requested Type Override Path Override Type
	// -------------- ------------------- -------------
	// A uvm_test_top.env.a1 A_ovr
	// B path1.b1 B_ovr
	// B path2.b2 B_override
	//
	// No type overrides are registered with this factory
	//
	// All types registered with the factory: 45 total
	// (types without type names will not be printed)
	// Type Name
	// ---------
	// A
	// A_ovr
	// B
	// B_override
	// B_ovr
	// environment
	// test
	// (*) Types with no associated type name will be printed as <unknown>
	// ####
	//
	// UVM_INFO top.sv(15) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A new
	// UVM_INFO top.sv(28) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A_ovr new
	// UVM_INFO top.sv(42) @ 0: reporter [B_ovr] B new
	// UVM_INFO top.sv(55) @ 0: reporter [B_ovr] B_ovr new
	// UVM_INFO top.sv(42) @ 0: reporter [B_override] B new
	// UVM_INFO top.sv(55) @ 0: reporter [B_override] B_ovr new
	// UVM_INFO top.sv(68) @ 0: reporter [B_override] B_override new
	// UVM_INFO top.sv(32) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] HELLO from override class 'A_ovr'
	// UVM_INFO top.sv(59) @ 0: reporter [b1] HELLO from override class 'B_ovr'
	// UVM_INFO top.sv(72) @ 0: reporter [b2] HELLO from override class 'B_override'

view raw set_instance_override_by_type_op.sv hosted with ❤ by GitHub

-------------------------------------------------------

set_inst_override_by_name
-------------------------------------------------------

	// set_inst_override_by_name
	`include "uvm.svh"
	import uvm_pkg::*;
	//--------------------uvm_component------------------------------
	class A extends uvm_agent;
	`uvm_component_utils(A)

	function new (string name="A", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A new"), UVM_LOW);
	endfunction : new

	virtual function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'A'"), UVM_LOW);
	endfunction : hello
	endclass : A

	class A_ovr extends A;
	`uvm_component_utils(A_ovr)

	function new (string name="A_ovr", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_ovr new"), UVM_LOW);
	endfunction : new

	function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : A_ovr

	//--------------------uvm_object------------------------------
	class B extends uvm_object;
	`uvm_object_utils(B)

	function new (string name="B");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B new"), UVM_LOW);
	endfunction : new

	virtual function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'B'"), UVM_LOW);
	endfunction : hello
	endclass : B

	class B_ovr extends B;
	`uvm_object_utils(B_ovr)

	function new (string name="B_ovr");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_ovr new"), UVM_LOW);
	endfunction : new

	function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : B_ovr

	class B_override extends B_ovr;
	`uvm_object_utils(B_override)

	function new (string name="B_override");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_override new"), UVM_LOW);
	endfunction : new

	function hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_override'"), UVM_LOW);
	endfunction : hello
	endclass : B_override

	//--------------------env class--------------------
	class environment extends uvm_env;
	`uvm_component_utils(environment)
	A a1;
	B b1, b2;

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

	function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	// arguments of create method:
	// 1. string name = ""
	// 2. uvm_component parent = null
	// 3. string contxt = ""
	// The contxt argument, if supplied, supercedes the parent's context.
	a1 = A::type_id::create("a1", this);
	b1 = B::type_id::create("b1", , "path1");
	b2 = B::type_id::create("b2", , "path2");

	a1.hello(); // This will print from overridden class A_ovr
	b1.hello(); // This will print from overridden class B_ovr
	b2.hello(); // This will print from overridden class B_override
	endfunction : build_phase
	endclass : environment

	//-------------------test class--------------------------
	class test extends uvm_test;
	`uvm_component_utils(test)
	environment env;

	function new(string name = "test", uvm_component parent = null);
	super.new(name, parent);
	endfunction : new

	virtual function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	env = environment::type_id::create("env", this);
	`uvm_info(get_full_name, $sformatf("TEST set_inst_override_by_name"), UVM_LOW);

	factory.set_inst_override_by_name("A", "A_ovr", {get_full_name, ".", "env.a1"}); // Working

	//factory.set_inst_override_by_name("B", "B_ovr", {get_full_name, ".", "env.b1"}); // Not working
	factory.set_inst_override_by_name("B", "B_ovr", "path1.b1"); // Working

	//factory.set_inst_override_by_name("B", "B_override", {get_full_name, ".", "env.b2"}); // Not working
	factory.set_inst_override_by_name("B", "B_override", "path2.b2"); // Working

	factory.print(); // This will print info about overridden classes.
	endfunction : build_phase
	endclass : test

	module top();
	initial begin
	run_test("test");
	end
	endmodule : top

view raw set_instance_override_by_name.sv hosted with ❤ by GitHub

-------------------------------------------------------

-------------------------------------------------------

	//Output:
	// UVM_INFO @ 0: reporter [RNTST] Running test test...
	// UVM_INFO top.sv(118) @ 0: uvm_test_top [uvm_test_top] TEST set_inst_override_by_name
	//
	// #### Factory Configuration (*)
	// Instance Overrides:
	// Requested Type Override Path Override Type
	// -------------- ------------------- -------------
	// A uvm_test_top.env.a1 A_ovr
	// B path1.b1 B_ovr
	// B path2.b2 B_override
	//
	// No type overrides are registered with this factory
	//
	// All types registered with the factory: 45 total
	// (types without type names will not be printed)
	// Type Name
	// ---------
	// A
	// A_ovr
	// B
	// B_override
	// B_ovr
	// environment
	// test
	// (*) Types with no associated type name will be printed as <unknown>
	// ####
	//
	// UVM_INFO top.sv(15) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A new
	// UVM_INFO top.sv(28) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A_ovr new
	// UVM_INFO top.sv(42) @ 0: reporter [B_ovr] B new
	// UVM_INFO top.sv(55) @ 0: reporter [B_ovr] B_ovr new
	// UVM_INFO top.sv(42) @ 0: reporter [B_override] B new
	// UVM_INFO top.sv(55) @ 0: reporter [B_override] B_ovr new
	// UVM_INFO top.sv(68) @ 0: reporter [B_override] B_override new
	// UVM_INFO top.sv(32) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] HELLO from override class 'A_ovr'
	// UVM_INFO top.sv(59) @ 0: reporter [b1] HELLO from override class 'B_ovr'
	// UVM_INFO top.sv(72) @ 0: reporter [b2] HELLO from override class 'B_override'

view raw set_instance_override_by_name_op.sv hosted with ❤ by GitHub

-------------------------------------------------------

set_type_override_by_type
-------------------------------------------------------

	// set_type_override_by_type
	`include "uvm.svh"
	import uvm_pkg::*;
	//--------------------uvm_component------------------------------
	class A extends uvm_agent;
	`uvm_component_utils(A)

	function new (string name="A", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'A'"), UVM_LOW);
	endfunction : hello
	endclass : A

	class A_ovr extends A;
	`uvm_component_utils(A_ovr)

	function new (string name="A_ovr", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : A_ovr

	//--------------------uvm_object------------------------------
	class B extends uvm_object;
	`uvm_object_utils(B)

	function new (string name="B");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'B'"), UVM_LOW);
	endfunction : hello
	endclass : B

	class B_ovr extends B;
	`uvm_object_utils(B_ovr)

	function new (string name="B_ovr");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : B_ovr

	class B_override extends B_ovr;
	`uvm_object_utils(B_override)

	function new (string name="B_override");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_override new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_override'"), UVM_LOW);
	endfunction : hello
	endclass : B_override

	//--------------------env class--------------------
	class environment extends uvm_env;
	`uvm_component_utils(environment)
	A a1;
	B b1, b2;

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

	function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	// arguments of create method:
	// 1. string name = ""
	// 2. uvm_component parent = null
	// 3. string contxt = ""
	// The contxt argument, if supplied, supercedes the parent's context.
	a1 = A::type_id::create("a1", this);
	b1 = B::type_id::create("b1", , "path1");
	b2 = B::type_id::create("b2", , "path2");

	void'(a1.hello()); // This will print from overridden class A_ovr
	void'(b1.hello()); // This will print from overridden class B_override
	void'(b2.hello()); // This will print from overridden class B_override
	endfunction : build_phase
	endclass : environment

	//-------------------test class--------------------------
	class test extends uvm_test;
	`uvm_component_utils(test)
	environment env;

	function new(string name = "test", uvm_component parent = null);
	super.new(name, parent);
	endfunction : new

	virtual function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	env = environment::type_id::create("env", this);
	`uvm_info(get_full_name, $sformatf("TEST set_inst_override_by_name"), UVM_LOW);

	factory.set_type_override_by_type(A::get_type(), A_ovr::get_type()); // Working

	factory.set_type_override_by_type(B::get_type(), B_override::get_type()); // Working

	factory.print(); // This will print info about overridden classes.
	endfunction : build_phase
	endclass : test

	module top();
	initial begin
	run_test("test");
	end
	endmodule : top

view raw set_type_override_by_type.sv hosted with ❤ by GitHub

-------------------------------------------------------

-------------------------------------------------------

	//Output:
	UVM_INFO @ 0: reporter [RNTST] Running test test...
	UVM_INFO testbench.sv(109) @ 0: uvm_test_top [uvm_test_top] TEST set_inst_override_by_name

	#### Factory Configuration (*)

	No instance overrides are registered with this factory

	Type Overrides:

	Requested Type Override Type
	-------------- -------------
	A A_ovr
	B B_override

	All types registered with the factory: 45 total
	(types without type names will not be printed)

	Type Name
	---------
	A
	A_ovr
	B
	B_override
	B_ovr
	environment
	snps_uvm_reg_bank_group
	snps_uvm_reg_map
	test
	(*) Types with no associated type name will be printed as <unknown>

	####

	UVM_INFO testbench.sv(9) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A new
	UVM_INFO testbench.sv(22) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A_ovr new
	UVM_INFO testbench.sv(36) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(49) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(62) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(36) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(49) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(62) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(26) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] HELLO from override class 'A_ovr'
	UVM_INFO testbench.sv(66) @ 0: reporter [b1] HELLO from override class 'B_override'
	UVM_INFO testbench.sv(66) @ 0: reporter [b2] HELLO from override class 'B_override'

view raw set_type_override_by_type_op.sv hosted with ❤ by GitHub

-------------------------------------------------------

set_type_override_by_name
-------------------------------------------------------

	// set_type_override_by_name
	`include "uvm.svh"
	import uvm_pkg::*;
	//--------------------uvm_component------------------------------
	class A extends uvm_agent;
	`uvm_component_utils(A)

	function new (string name="A", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'A'"), UVM_LOW);
	endfunction : hello
	endclass : A

	class A_ovr extends A;
	`uvm_component_utils(A_ovr)

	function new (string name="A_ovr", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : A_ovr

	//--------------------uvm_object------------------------------
	class B extends uvm_object;
	`uvm_object_utils(B)

	function new (string name="B");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'B'"), UVM_LOW);
	endfunction : hello
	endclass : B

	class B_ovr extends B;
	`uvm_object_utils(B_ovr)

	function new (string name="B_ovr");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : B_ovr

	class B_override extends B_ovr;
	`uvm_object_utils(B_override)

	function new (string name="B_override");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_override new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_override'"), UVM_LOW);
	endfunction : hello
	endclass : B_override

	//--------------------env class--------------------
	class environment extends uvm_env;
	`uvm_component_utils(environment)
	A a1;
	B b1, b2;
	B_ovr b3;

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

	function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	// arguments of create method:
	// 1. string name = ""
	// 2. uvm_component parent = null
	// 3. string contxt = ""
	// The contxt argument, if supplied, supercedes the parent's context.
	// contxt argument is not required for set_type_override_*,
	// It is only required for set_inst_override_* to locate
	// instance of uvm_object which is not part of uvm hierarchy.
	a1 = A::type_id::create("a1", this);
	b1 = B::type_id::create("b1", , "path1");
	b2 = B::type_id::create("b2");
	b3 = B_ovr::type_id::create("b3");

	void'(a1.hello()); // This will print from overridden class A_ovr
	void'(b1.hello()); // This will print from overridden class B_override
	void'(b2.hello()); // This will print from overridden class B_override
	void'(b3.hello()); // This will print from overridden class B_ovr
	endfunction : build_phase
	endclass : environment

	//-------------------test class--------------------------
	class test extends uvm_test;
	`uvm_component_utils(test)
	environment env;

	function new(string name = "test", uvm_component parent = null);
	super.new(name, parent);
	endfunction : new

	virtual function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	env = environment::type_id::create("env", this);
	`uvm_info(get_full_name, $sformatf("TEST set_inst_override_by_name"), UVM_LOW);

	factory.set_type_override_by_name("A", "A_ovr"); // Working

	factory.set_type_override_by_name("B", "B_override"); // Working

	factory.print(); // This will print info about overridden classes.
	endfunction : build_phase
	endclass : test

	module top();
	initial begin
	run_test("test");
	end
	endmodule : top

view raw set_type_override_by_name.sv hosted with ❤ by GitHub

-------------------------------------------------------

-------------------------------------------------------

	//Output:
	UVM_INFO @ 0: reporter [RNTST] Running test test...
	UVM_INFO testbench.sv(117) @ 0: uvm_test_top [uvm_test_top] TEST set_inst_override_by_name

	#### Factory Configuration (*)

	No instance overrides are registered with this factory

	Type Overrides:

	Requested Type Override Type
	-------------- -------------
	A A_ovr
	B B_override

	All types registered with the factory: 45 total
	(types without type names will not be printed)

	Type Name
	---------
	A
	A_ovr
	B
	B_override
	B_ovr
	environment
	snps_uvm_reg_bank_group
	snps_uvm_reg_map
	test
	(*) Types with no associated type name will be printed as <unknown>

	####

	UVM_INFO testbench.sv(11) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A new
	UVM_INFO testbench.sv(24) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A_ovr new
	UVM_INFO testbench.sv(38) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(51) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(64) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(38) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(51) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(64) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(38) @ 0: reporter [B_ovr] B new
	UVM_INFO testbench.sv(51) @ 0: reporter [B_ovr] B_ovr new
	UVM_INFO testbench.sv(28) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] HELLO from override class 'A_ovr'
	UVM_INFO testbench.sv(68) @ 0: reporter [b1] HELLO from override class 'B_override'
	UVM_INFO testbench.sv(68) @ 0: reporter [b2] HELLO from override class 'B_override'
	UVM_INFO testbench.sv(55) @ 0: reporter [b3] HELLO from override class 'B_ovr'

view raw set_type_override_by_name_op.sv hosted with ❤ by GitHub

-------------------------------------------------------

set_inst_override_* has high precedence than set_type_override_*.
i.e. If any particular instance of class is override by using set_inst_override_* and type of same class is overridden by using set_type_override_* then that particular instance of class is overridden by set_inst_override_* and rest other instances are overridden by set_type_override_*

-------------------------------------------------------

	// set_inst_override_* hase high priority than set_type_override_*
	`include "uvm.svh"
	import uvm_pkg::*;
	//--------------------uvm_component------------------------------
	class A extends uvm_agent;
	`uvm_component_utils(A)

	function new (string name="A", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'A'"), UVM_LOW);
	endfunction : hello
	endclass : A

	class A_ovr extends A;
	`uvm_component_utils(A_ovr)

	function new (string name="A_ovr", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : A_ovr

	class A_override extends A;
	`uvm_component_utils(A_override)

	function new (string name="A_override", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_override new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_override'"), UVM_LOW);
	endfunction : hello
	endclass : A_override

	//--------------------uvm_object------------------------------
	class B extends uvm_object;
	`uvm_object_utils(B)

	function new (string name="B");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'B'"), UVM_LOW);
	endfunction : hello
	endclass : B

	class B_ovr extends B;
	`uvm_object_utils(B_ovr)

	function new (string name="B_ovr");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : B_ovr

	class B_override extends B_ovr;
	`uvm_object_utils(B_override)

	function new (string name="B_override");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_override new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_override'"), UVM_LOW);
	endfunction : hello
	endclass : B_override

	//--------------------env class--------------------
	class environment extends uvm_env;
	`uvm_component_utils(environment)
	A a1, a2, a3;
	B b1, b2, b3;

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

	function void build_phase(uvm_phase phase);
	super.build_phase(phase);

	a1 = A::type_id::create("a1", this);
	a2 = A::type_id::create("a2", this);
	a3 = A::type_id::create("a3", this);
	b1 = B::type_id::create("b1", , "path1");
	b2 = B::type_id::create("b2", , "path2");
	b3 = B::type_id::create("b3", , "path3");

	void'(a1.hello()); // This will print from overridden class A_ovr
	void'(a2.hello()); // This will print from overridden class A_ovr
	void'(a3.hello()); // This will print from overridden class A_override
	void'(b1.hello()); // This will print from overridden class B_ovr
	void'(b2.hello()); // This will print from overridden class B_override
	void'(b3.hello()); // This will print from overridden class B_override
	endfunction : build_phase
	endclass : environment

	//-------------------test class--------------------------
	class test extends uvm_test;
	`uvm_component_utils(test)
	environment env;

	function new(string name = "test", uvm_component parent = null);
	super.new(name, parent);
	endfunction : new

	virtual function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	env = environment::type_id::create("env", this);
	`uvm_info(get_full_name, $sformatf("TEST set_inst_override_by_name"), UVM_LOW);


	factory.set_type_override_by_type(A::get_type(), A_ovr::get_type()); // Working
	factory.set_type_override_by_name("B", "B_override"); // Working

	factory.set_inst_override_by_type(A::get_type(), A_override::get_type(), {get_full_name, ".", "env.a3"});
	factory.set_inst_override_by_name("B", "B_ovr", "path1.b1");

	factory.print(); // This will print info about overridden classes.
	endfunction : build_phase
	endclass : test

	module top();
	initial begin
	run_test("test");
	end
	endmodule : top

view raw override_precedence.sv hosted with ❤ by GitHub

-------------------------------------------------------

-------------------------------------------------------

	//Output:
	UVM_INFO @ 0: reporter [RNTST] Running test test...
	UVM_INFO testbench.sv(122) @ 0: uvm_test_top [uvm_test_top] TEST set_inst_override_by_name

	#### Factory Configuration (*)

	Instance Overrides:

	Requested Type Override Path Override Type
	-------------- ------------------- -------------
	A uvm_test_top.env.a3 A_override
	B path1.b1 B_ovr

	Type Overrides:

	Requested Type Override Type
	-------------- -------------------
	A A_ovr
	B B_override

	All types registered with the factory: 46 total
	(types without type names will not be printed)

	Type Name
	---------
	A
	A_override
	A_ovr
	B
	B_override
	B_ovr
	environment
	snps_uvm_reg_bank_group
	snps_uvm_reg_map
	test
	(*) Types with no associated type name will be printed as <unknown>

	####

	UVM_INFO testbench.sv(7) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A new
	UVM_INFO testbench.sv(20) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A_ovr new
	UVM_INFO testbench.sv(7) @ 0: uvm_test_top.env.a2 [uvm_test_top.env.a2] A new
	UVM_INFO testbench.sv(20) @ 0: uvm_test_top.env.a2 [uvm_test_top.env.a2] A_ovr new
	UVM_INFO testbench.sv(7) @ 0: uvm_test_top.env.a3 [uvm_test_top.env.a3] A new
	UVM_INFO testbench.sv(33) @ 0: uvm_test_top.env.a3 [uvm_test_top.env.a3] A_override new
	UVM_INFO testbench.sv(47) @ 0: reporter [B_ovr] B new
	UVM_INFO testbench.sv(60) @ 0: reporter [B_ovr] B_ovr new
	UVM_INFO testbench.sv(47) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(60) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(73) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(47) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(60) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(73) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(24) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] HELLO from override class 'A_ovr'
	UVM_INFO testbench.sv(24) @ 0: uvm_test_top.env.a2 [uvm_test_top.env.a2] HELLO from override class 'A_ovr'
	UVM_INFO testbench.sv(37) @ 0: uvm_test_top.env.a3 [uvm_test_top.env.a3] HELLO from override class 'A_override'
	UVM_INFO testbench.sv(64) @ 0: reporter [b1] HELLO from override class 'B_ovr'
	UVM_INFO testbench.sv(77) @ 0: reporter [b2] HELLO from override class 'B_override'
	UVM_INFO testbench.sv(77) @ 0: reporter [b3] HELLO from override class 'B_override'

view raw override_precedence_op.sv hosted with ❤ by GitHub

-------------------------------------------------------

UVM also support override through command line,
+uvm_set_inst_override=,,
+uvm_set_type_override=,[,]
work like the name based overrides in the factory--factory.set_inst_override_by_name() and factory.set_type_override_by_name().

Let's implement same example as above using command line arguments.
-------------------------------------------------------

	//--------------------uvm_component------------------------------
	class A extends uvm_agent;
	`uvm_component_utils(A)

	function new (string name="A", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'A'"), UVM_LOW);
	endfunction : hello
	endclass : A

	class A_ovr extends A;
	`uvm_component_utils(A_ovr)

	function new (string name="A_ovr", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : A_ovr

	class A_override extends A;
	`uvm_component_utils(A_override)

	function new (string name="A_override", uvm_component parent);
	super.new(name, parent);
	`uvm_info(get_full_name, $sformatf("A_override new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'A_override'"), UVM_LOW);
	endfunction : hello
	endclass : A_override

	//--------------------uvm_object------------------------------
	class B extends uvm_object;
	`uvm_object_utils(B)

	function new (string name="B");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B new"), UVM_LOW);
	endfunction : new

	virtual function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from Original class 'B'"), UVM_LOW);
	endfunction : hello
	endclass : B

	class B_ovr extends B;
	`uvm_object_utils(B_ovr)

	function new (string name="B_ovr");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_ovr new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_ovr'"), UVM_LOW);
	endfunction : hello
	endclass : B_ovr

	class B_override extends B_ovr;
	`uvm_object_utils(B_override)

	function new (string name="B_override");
	super.new(name);
	`uvm_info(get_full_name, $sformatf("B_override new"), UVM_LOW);
	endfunction : new

	function void hello();
	`uvm_info(get_full_name, $sformatf("HELLO from override class 'B_override'"), UVM_LOW);
	endfunction : hello
	endclass : B_override

	//--------------------env class--------------------
	class environment extends uvm_env;
	`uvm_component_utils(environment)
	A a1, a2, a3;
	B b1, b2, b3;

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

	function void build_phase(uvm_phase phase);
	super.build_phase(phase);

	a1 = A::type_id::create("a1", this);
	a2 = A::type_id::create("a2", this);
	a3 = A::type_id::create("a3", this);
	b1 = B::type_id::create("b1", , "path1");
	b2 = B::type_id::create("b2", , "path2");
	b3 = B::type_id::create("b3", , "path3");

	void'(a1.hello()); // This will print from overridden class A_ovr
	void'(a2.hello()); // This will print from overridden class A_ovr
	void'(a3.hello()); // This will print from overridden class A_override
	void'(b1.hello()); // This will print from overridden class B_ovr
	void'(b2.hello()); // This will print from overridden class B_override
	void'(b3.hello()); // This will print from overridden class B_override
	endfunction : build_phase
	endclass : environment

	//-------------------test class--------------------------
	class test extends uvm_test;
	`uvm_component_utils(test)
	environment env;

	function new(string name = "test", uvm_component parent = null);
	super.new(name, parent);
	endfunction : new

	virtual function void build_phase(uvm_phase phase);
	super.build_phase(phase);
	env = environment::type_id::create("env", this);
	`uvm_info(get_full_name, $sformatf("TEST set_inst_override_by_name"), UVM_LOW);

	//factory.set_type_override_by_type(A::get_type(), A_ovr::get_type()); // Working
	//factory.set_type_override_by_name("B", "B_override"); // Working

	//factory.set_inst_override_by_type(A::get_type(), A_override::get_type(), {get_full_name, ".", "env.a3"});
	//factory.set_inst_override_by_name("B", "B_ovr", "path1.b1");

	factory.print(); // This will print info about overridden classes.
	endfunction : build_phase
	endclass : test

	module top();
	initial begin
	run_test("test");
	end
	endmodule : top

view raw override_by_cmd_line.sv hosted with ❤ by GitHub

-------------------------------------------------------

Simulation time argument:
+uvm_set_inst_override=A,A_override,uvm_test_top.env.a3 \
+uvm_set_inst_override=B,B_ovr,path1.b1 \
+uvm_set_type_override=A,A_ovr \
+uvm_set_type_override=B,B_override
-------------------------------------------------------

	UVM_INFO @ 0: reporter [RNTST] Running test test...
	UVM_INFO @ 0: reporter [INSTOVR] Applying instance override from the command line: +uvm_set_inst_override=A,A_override,uvm_test_top.env.a3
	UVM_INFO @ 0: reporter [INSTOVR] Applying instance override from the command line: +uvm_set_inst_override=B,B_ovr,path1.b1
	UVM_INFO @ 0: reporter [UVM_CMDLINE_PROC] Applying type override from the command line: +uvm_set_type_override=A,A_ovr
	UVM_INFO @ 0: reporter [UVM_CMDLINE_PROC] Applying type override from the command line: +uvm_set_type_override=B,B_override
	UVM_INFO testbench.sv(122) @ 0: uvm_test_top [uvm_test_top] TEST set_inst_override_by_name

	#### Factory Configuration (*)

	Instance Overrides:

	Requested Type Override Path Override Type
	-------------- ------------------- -------------
	A uvm_test_top.env.a3 A_override
	B path1.b1 B_ovr

	Type Overrides:

	Requested Type Override Type
	-------------- -------------------
	A A_ovr
	B B_override

	All types registered with the factory: 46 total
	(types without type names will not be printed)

	Type Name
	---------
	A
	A_override
	A_ovr
	B
	B_override
	B_ovr
	environment
	snps_uvm_reg_bank_group
	snps_uvm_reg_map
	test
	(*) Types with no associated type name will be printed as <unknown>

	####

	UVM_INFO testbench.sv(7) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A new
	UVM_INFO testbench.sv(20) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] A_ovr new
	UVM_INFO testbench.sv(7) @ 0: uvm_test_top.env.a2 [uvm_test_top.env.a2] A new
	UVM_INFO testbench.sv(20) @ 0: uvm_test_top.env.a2 [uvm_test_top.env.a2] A_ovr new
	UVM_INFO testbench.sv(7) @ 0: uvm_test_top.env.a3 [uvm_test_top.env.a3] A new
	UVM_INFO testbench.sv(33) @ 0: uvm_test_top.env.a3 [uvm_test_top.env.a3] A_override new
	UVM_INFO testbench.sv(47) @ 0: reporter [B_ovr] B new
	UVM_INFO testbench.sv(60) @ 0: reporter [B_ovr] B_ovr new
	UVM_INFO testbench.sv(47) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(60) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(73) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(47) @ 0: reporter [B_override] B new
	UVM_INFO testbench.sv(60) @ 0: reporter [B_override] B_ovr new
	UVM_INFO testbench.sv(73) @ 0: reporter [B_override] B_override new
	UVM_INFO testbench.sv(24) @ 0: uvm_test_top.env.a1 [uvm_test_top.env.a1] HELLO from override class 'A_ovr'
	UVM_INFO testbench.sv(24) @ 0: uvm_test_top.env.a2 [uvm_test_top.env.a2] HELLO from override class 'A_ovr'
	UVM_INFO testbench.sv(37) @ 0: uvm_test_top.env.a3 [uvm_test_top.env.a3] HELLO from override class 'A_override'
	UVM_INFO testbench.sv(64) @ 0: reporter [b1] HELLO from override class 'B_ovr'
	UVM_INFO testbench.sv(77) @ 0: reporter [b2] HELLO from override class 'B_override'
	UVM_INFO testbench.sv(77) @ 0: reporter [b3] HELLO from override class 'B_override'

view raw override_by_cmd_line_op.sv hosted with ❤ by GitHub

-------------------------------------------------------

11 comments:

maddy_uk1 October 2016 at 02:09
Great post. I see some of the code is commented and for some you said not working. Is that something you tried before coming out with a working example.

On a related note, can you add examples for parameterized class overrides ?
maddy_uk1 October 2016 at 03:40
Also, running the examples as it is gives error as uvm.svh is not inside package or module ?
Vineet Sharma13 February 2019 at 21:06
Very nice article. many many thanks
Anonymous24 October 2019 at 16:58
you should not call set_override function , after creating environment.
you should call it before.
Unknown7 January 2020 at 12:16
Hi Sagar,
Just wanted to know. if by any chance you tried the above overriding example for parameterized class
Yajur16 January 2020 at 16:33
One more way :

B_driver::type_id::set_type_override(D_driver::get_type());
gariks30 January 2020 at 02:22
Thank You Sagar...these are nice articles to understanding UVM fundamentals.as per your examples what ever content is not working might be a tool problem.I have tested not working code from your examples with latest version of VCS and I can see it is working after adding below code.
uvm_factory factory; //declaration in test class
//in build_phase function just call below line to resolve factory object
factory = uvm_factory::get();

also Anonymous mentioned in above chat.That would be UVM coding guide line.once we do required object overriding,then we can construct env based on new overridden objects(at least from this example).
Jitander Rawat20 February 2020 at 15:07
i am facing error in set_int_override_type example

Error (suppressible): (vsim-13215) factory_type_override.sv(121): Cannot assign an unpacked type 'class work.uvm_pkg::uvm_object_registry #(class work.factory_type_override_sv_unit::B_ovr, "B_ovr")' to a packed type 'reg'.

Unresolved reference to 'factory' in $root.factory.print.

i am not able to resole

Saturday, 30 April 2016

Override in UVM using factory with Example

11 comments: