xilinx - Connecting ports by name in VHDL, UCF-style -

i have vhdl entity defined this:

entity realentity   port(     clk_50mhz: in std_logic;     led : out std_logic_vector(3 downto 0)     ); end realentity; 

if have ucf entries led<0>..led<3> , clk_50mhz, can compile entity directly.

however, don't have 50 mhz clock on board, have use clock manager chip. i'm using xilinx tools has wizard add dcm core, , wrap in vhdl entity easy use:

entity dcm   port(     clk_32mhz: in std_logic;     clk_50mhz: out std_logic     ); end dcm; 

where clk_32mhz exists in ucf.

to connect these two, using third entity used toplevel one:

entity main   port(     clk_32mhz : in  std_logic;     led       : out std_logic_vector(3 downto 0)     ); end main;  architecture arch of main   signal clk_50mhz : std_logic;    component dcm     port(       clk_32mhz : in  std_logic;       clk_50mhz : out std_logic       );   end component;    component realentity     port(clk_50mhz : in  std_logic;          led       : out std_logic_vector(3 downto 0)          );   end component;  begin   inst_dcm : dcm     port map(       clk_32mhz => clk_32mhz,       clk_50mhz => clk_50mhz       );    inst_realentity : realentity     port map(       clk_50mhz => clk_50mhz,       led       => led       );  end arch; 

as can see, third entity 100% boilerplate. question is, possible avoid writing main entity, , instead use realentity , dcm directly, , connect 2 clk_50mhz ports virtue of them sharing name, emulating clk_50mhz being present in ucf file?

somehow have tell tools how wire dcm , real entity. "boilerplate" top-level entity achieves that. can't in ucf file doesn't allow create connections, attach various attributes connections have made.

so problem becomes 1 of tools exist enable "wire things up" efficiently possible. brian has enumerated options there...

you can reduce boilerplate using direct instantiation. remove component declarations , do:

inst_realentity : entity work.realentity     port map(       clk_50mhz => clk_50mhz,       led       => led       );