Verilog attributes?

[nkyparissas]

Is there a way to generate Verilog code with attributes? For example, is there a way to tell via my BSV code to generate a
(* keep_hierarchy = "yes" *)
attribute when declaring a module in Verilog?

[quark17]

Issue #445 is an enhancement request to support this. In the meantime, a workaround is to use the doc attribute combined with a post-processing script.

The doc attribute can be used to put comments in the generated Verilog. You can apply it to a module, like this:

(* doc = "ATTRIBUTE: keep_hierarchy = \"yes\"" *)
(* synthesize *)
module mkTest (Ifc);

Then you can tell BSC to run a post-processing script on its generated modules, using the flag -verilog-filter:

bsc  -verilog  -verilog-filter doc_to_attr.py  Test.bsv

Then you'd need to write a script (doc_to_attr.py say), which looks for something unique in the comments (such as ATTRIBUTE:) and adjusts that into an attribute. Unfortunately, the doc attributes for modules will place the string in the header comment at the top of the file, so a simple line replacement won't work; your script will need to look for the later module..endmodule block and move the attribute to be there. For example, the above attribute would result in this:

//
// Generated by Bluespec Compiler, version 2023.01-39-g42fb7b6c (build 42fb7b6c)
//
// On Fri Sep 29 12:13:43 NZDT 2023
//
//
// Ports:
// Name                         I/O  size props
// CLK                            I     1 unused
// RST_N                          I     1 unused
//
// No combinational paths from inputs to outputs
//
//
// ATTRIBUTE: keep_hierarchy = "yes"
//
//

`ifdef BSV_ASSIGNMENT_DELAY
`else
  `define BSV_ASSIGNMENT_DELAY
`endif

`ifdef BSV_POSITIVE_RESET
  `define BSV_RESET_VALUE 1'b1
  `define BSV_RESET_EDGE posedge
`else
  `define BSV_RESET_VALUE 1'b0
  `define BSV_RESET_EDGE negedge
`endif

module mkTest(CLK,
              RST_N);
  input  CLK;
  input  RST_N;

endmodule  // mkTest

[nkyparissas]

Thank you! I am already using a similar script, but I was wondering. :)