How to get source code location information

uses
  EClasses,
  EDebugInfo;

procedure Test;
begin

end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Info: TELLocationInfo;
begin
  Info := GetLocationInfo(@Test);
  Label1.Caption := Info.UnitName + '.' + Info.ProcedureName;
  // Will output 'Unit1.Test'
end;