Bug 20155 – Web Inspector: profiler lumps together anonymous functions created by "new Function" and unnamed evals

• Component: Web Inspector
• Status: RESOLVED FIXED

[Oliver Hunt]

Create multiple functions with the same name, say
f1 = new Function("return 1;")
f2 = new Function("return 2;")

And call them lots of times.  Both functions will be called anonymous, and will get the same entry in the profiler.

[Kevin McCullough]

The title is wrong, if you have two functions with the same name they will not get the same entry in the profiler.  Two anonymous function functions will, because they don't have any line number information or other data to distinguish them.

This would be fixed if we fix https://bugs.webkit.org/show_bug.cgi?id=19229

[Timothy Hatcher]

Why don't we have line numbers? I guess the reason is more specific. If the anonymous function is made with new Function() it seems. Because we do the right things for:

f1 = function() { return 1; }
f2 = function() { return 2; }

[Oliver Hunt]

I suspect that the profiler should be comparing sourceId (or whatever that property is) because
eval("function(){1}") and eval("function(){2}") will both have the same line number, and url (eg. no url)

--Oliver

[Kevin McCullough]

It's dependent on what information is available at the time of execution.  Previously filename and line number were not known.  Can we know the sourceId at execution time?

[Oliver Hunt]

Do we not provide such info?  we do for exceptions and the debugger, so the info is actually available to us.

[Timothy Hatcher]

*** Bug 25175 has been marked as a duplicate of this bug. ***

[Patrick Mueller]

Created attachment 50934 [details]
sample named/unnamed and source/eval functions for debugging/profiling

I had put this sample together to submit a new bug regarding lack of source information provided to the profiler, but then found this bug, so thought I'd just paste it on here, since it seems relevant enough.

What it basically shows is that using the latest bits available (including displayName property on Functions to name them, and //@sourceURL= to name eval()'d chunks), the profiler still doesn't provide the source information for eval()'d functions.  But the debugger does.  One of my users has requested that the //@sourceURL bit be supported for profiling as well as debugging.

[Radar WebKit Bug Importer]

<rdar://problem/19281484>

[Timothy Hatcher]

Is this an issue with the new sampling profiler?

[Saam Barati]

(In reply to comment #9)
> Is this an issue with the new sampling profiler?

I'm not sure. I will look into it.

[Timothy Hatcher]

This works as expected in WebKit now with the attached test case.