uvm_component 构造函数中的父参数

Question

我希望my_child在下面的代码中继承my_parent的say_hello函数，但它没有。

谁能给我解释一下 parent 参数的作用？

class my_parent extends uvm_component;
  `uvm_component_utils(my_parent);
  
  function new(string name = "my_parent", uvm_component parent);
    super.new(name, parent);
  endfunction: new
  
  function void say_hello;
    $display("Hello, UVM!");
  endfunction: say_hello
endclass: my_parent
/*========================================*/

class my_child extends uvm_component;
  `uvm_component_utils(my_child);
  
  function new(string name = "my_child", uvm_component parent);
    super.new(name, parent);
  endfunction: new
endclass: my_child
/*========================================*/

module top;
  my_parent p;
  my_child c;
  
  initial begin
    p = my_parent::type_id::create("p", null);
    c = my_child::type_id::create("c", p);
    c.say_hello;
  end 
endmodule: top

Answer 1

当您想从 my_parent 继承时，您应该从 my_parent class 扩展 my_child class 而不是 uvm_component class。变化：

class my_child extends uvm_component;

至：

class my_child extends my_parent;

当您进行此更改并运行模拟时，它会按预期打印以下内容：

Hello, UVM!

parent 变量在 uvm_component 下的 UVM Class Reference 文档中有解释。

Answer 2

您混淆了术语 parent 和 child 与 [=29= 】传承。它们是不同的 objects。一个 parent 创建一个 child，而 uvm_component 代表数据库中的分层家谱。您创建的每个组件都有一个 parent 句柄，parent 有一个句柄列表，即 children.

class my_child extends uvm_component;
  `uvm_component_utils(my_child);
  function new(string name = "my_child", uvm_component parent);
    super.new(name, parent);
  endfunction: new
endclass: my_child
class my_parent extends uvm_component;
  `uvm_component_utils(my_parent);
  my_child child;
  function new(string name = "my_parent", uvm_component parent);
    super.new(name, parent);
  endfunction: new
  function void build_phase(uvm_phase phase;
     child = my_child::type_id::create("child", this); // 'this' is the parent object
  endfunction : build_phase
endclass: my_parent
module top;
  my_parent p;  
  initial begin
    p = my_parent::type_id::create("p", null);
  end 
endmodule: top

当使用继承时，我们有 entended 或 derived classes，它们不是 child基仁class.

import uvm_pkg::*;
`include "uvm_macros.svh"
class my_child extends uvm_component;
  `uvm_component_utils(my_child);

  function new(string name = "my_child", uvm_component parent);
    super.new(name, parent);
  endfunction: new
  task  run_phase(uvm_phase phase);
    $display("Hello, UVM!, from base");
  endtask: run_phase
endclass: my_child
class my_parent extends uvm_component;
  `uvm_component_utils(my_parent);
  my_child child;
  function new(string name = "my_parent", uvm_component parent);
    super.new(name, parent);
  endfunction: new
  function void build_phase(uvm_phase phase);
    child = my_child::type_id::create("cchild", this); // 'this' is the parent object
  endfunction : build_phase
endclass: my_parent
class my_child_extended extends my_child;
  `uvm_component_utils(my_child_extended);

  function new(string name = "my_child", uvm_component parent);
    super.new(name, parent);
  endfunction: new
endclass: my_child_extended
module top;
  my_parent p;  
  initial begin
    my_child::type_id::set_type_override(my_child_extended::get_type());
    run_test("my_parent");
  end 
endmodule: top

uvm_component 构造函数中的父参数

The parent argument in the uvm_component constructor

system-verilog

uvm