Support quoted strings as arguments to passes

[gussmith23]

Feature Description

I'd like to be able to call a pass like

pass_name "some string" "some other string maybe having \"escaped quotes\""

and have the args list appear as

["pass_name", "some string", "some other string maybe having \"escaped quotes\""]

It currently seems like that might not be possible with the parser. Is that true, or am I missing something?

[povik]

Related: #4429

[whitequark]

IIRC this also affects bugpoint.

[gussmith23]

It seems like this might be supported by the long_strings arg of next_token -- when true, it seems like next_token will grab an entire quoted string as one token (though it looks like it will break on escaped quotes \"). The relevant arg parsing code even sets next_token to true. However, despite this, quoted strings still don't seem to be parsed correctly. I'm wondering if there's bug here:

yosys/kernel/yosys.cc

Lines 201 to 208 in 960bca0

	size_t pos_end = text.find_first_of(sep, pos_begin);
	if (pos_end == std::string::npos)
	pos_end = text.size();
	std::string token = text.substr(pos_begin, pos_end-pos_begin);
	text = text.substr(pos_end);
	return token;

Essentially, if I pass command "some string", next_token will grab command as the first token and return "some string" (note the space) as the rest of the string. Because this string doesn't start with ", it won't trigger the long_strings case I think.

[KrystalDelusion]

Oh huh, I was looking into this for log but it seemed like it was already being handled well enough at the kernel level. I certainly wasn't getting any issues of spaces at the start of strings in log.

I wonder if it's a difference between void Pass::call(RTLIL::Design *design, std::string command) and void Pass::call(RTLIL::Design *design, std::vector<std::string> args)? The former appears to skip spaces (and tabs) in the cmd_buf directly before attempting to grab the next token. That is probably why it works there but not other places?

yosys/kernel/register.cc

Lines 280 to 291 in 960bca0

	for (auto c : cmd_buf) {
	if (c == ' ' || c == '\t')
	continue;
	if (c == '\r' || c == '\n')
	found_nl = true;
	break;
	}
	if (found_nl) {
	call(design, args);
	args.clear();
	}
	tok = next_token(cmd_buf, " \t\r\n", true);

[gussmith23]

Am I able to choose which one should be used when implementing a Pass? I override execute, which i assume is called by call.

[KrystalDelusion]

That I do not know

[KrystalDelusion]

The difference between which call is used is whether it is called with a string (which is the one you want for quote parsing), or as a list of strings (which does not). The only way to get the latter (as far as I can tell), is via tee, debug, and trace, all of which are called via the former and so have already had quotes parsed; or if your pass is a frontend, because for some reason frontends are handled slightly differently.

[KrystalDelusion]

Oh actually backends also run their own arg parsing, and don't use call at all. See

yosys/kernel/register.cc

Lines 712 to 720 in 960bca0

	void Backend::backend_call(RTLIL::Design *design, std::ostream *f, std::string filename, std::string command)
	{
	std::vector<std::string> args;
	char *s = strdup(command.c_str());
	for (char *p = strtok(s, " \t\r\n"); p; p = strtok(NULL, " \t\r\n"))
	args.push_back(p);
	free(s);
	backend_call(design, f, filename, args);
	}