--prof-process CLI args no longer work in 10.10.0

[bengl]

• Version: v10.10.0
• Platform: Linux 4.18.5-arch1-1-ARCH deps: update openssl to 1.0.1j #1 SMP PREEMPT Fri Aug 24 12:48:58 UTC 2018 x86_64 GNU/Linux
• Subsystem: cli

Prior Node 10.10.0, the node --prof-process tool could be passed arguments altering its behavior. For example, --preprocess could be passed to deliver JSON data, and -j to only show JS VM ticks.

It seems that in Node 10.10.0, none of the --prof-process-specific arguments work anymore.

This currenly breaks 0x, clinic flame and probably some other perf-analysis tools.

e.g.

Node 10.9.0

$ node --prof-process --preprocess isolate-0x3b065a0-v8.log
# ... tons of useful JSON data

Node 10.10.0

$ node --prof-process --preprocess isolate-0x3b065a0-v8.log
node: bad option: --preprocess

I think this might be because of #22490. (/cc @addaleax)

[targos]

Are those arguments documented somewhere? I didn't know about them before you opened this issue

[joyeecheung]

This looks like an argument being passed down to the v8 scripts by v8_prof_processor.js, it's supposed to be treated as an exec argument but the file is run by us when --prof-process is on

node/lib/internal/v8_prof_processor.js

Lines 31 to 37 in 03b8258

	tickArguments.push.apply(tickArguments, process.argv.slice(1));
	script = `(function(module, require) {
	arguments = ${JSON.stringify(tickArguments)};
	function write (s) { process.stdout.write(s) }
	function printErr(err) { console.error(err); }
	${script}
	})`;

[addaleax]

This currenly breaks 0x, clinic flame and probably some other perf-analysis tools.

Would clinic be a candidate for CITGM?

I think this might be because of #22490. (/cc @addaleax)

#22392 could be the culprit too – either way, this is probably my fault.

[joyeecheung]

Maybe we should just break out of the argument parse loop once we reach --prof-process? That's how the user would've imagined how it works?

[addaleax]

Proposed fix in #22790, would be cool if you could try that?

[jasnell]

We can definitely explore getting clinic into citgm