Verilog file list suport

[JasonBrave]

What are the reasons/motivation for this change?

Most large Verilog/SystemVerilog IP use a file list/command '.f' file to hold list of Verilog file need to be compiled, this change make yosys able to directly parse file list.

Explain how this is achieved.

Implement a read_verilog_file_list command, that read in file list, and calls read_verilog on each Verilog file in the file list. Currently the command only handles file path in file list file, in a future PR I will implement support for +define+ and +incdir+ in file list file.

If applicable, please suggest to reviewers how they can test the change.

[udif]

Please note that most, if not all tools, accept any command line argument in their file lists, not just filenames or +define/+incdir.
As far as I remember, the slang front end handles this by reading -f files recursively as part of the command line parser.

[KrystalDelusion]

If you're adding file list support for the verilog frontend, you should update the read pass in /frontends/verific/verific.cc to call it.

[KrystalDelusion]

@udif The verific frontend for Yosys doesn't do this, so I don't think there's any reason that the read_verilog frontend should. It does however allow recursive calls with -f/-F in the file list. Also it calls it a command-file instead of a file list.

[JasonBrave]

All comments addressed, please review @KrystalDelusion

[KrystalDelusion]

read_verilog_file_list is gated by !defined(__wasm), so it's usage here should be too.

Suggested change

	args[0] = "read_verilog_file_list";
	#if !defined(__wasm)
	args[0] = "read_verilog_file_list";
	#else
	cmd_error(args, 1, "Command files are not supported on this platform.\n");
	#endif

[KrystalDelusion]

Suggested change

	log(" File list file contains list of Verilog files to be parsed, any path is treated relative to the file list file\n");
	log(" File list file contains list of Verilog files to be parsed, any path is\n");
	log(" treated relative to the file list file\n");

[KrystalDelusion]

Suggested change

	log("Parse a Verilog file list, and pass the list of Verilog files to read_verilog command.\n");
	log("Parse a Verilog file list, and pass the list of Verilog files to read_verilog\n");
	log("command.\n");

[KrystalDelusion]

Help messages should break at 80 characters (which is why the |---v---| guides are there).

[KrystalDelusion]

Suggested change

	log(" File list file contains list of Verilog files to be parsed, any path is treated relative to current working directroy\n");
	log(" File list file contains list of Verilog files to be parsed, any path is\n");
	log(" treated relative to current working directroy\n");