Xcode9b2 - slow performance jumping to symbol definition in pathologically large objc file

Originator:markd
Number:rdar://32968244 Date Originated:6/24/2017
Status:Open Resolved:
Product:Developer Tools Product Version:Version 9.0 beta 2 (9M137d)
Classification:Performance Reproducible:Sometimes
 
Summary:
Hi!

Much to my chagrin I have an objc source file that is 10K LoC.  Jumping to a symbol definition can take 2-5 seconds.  Xcode8 is near instantaneous.

Here's a video: https://www.dropbox.com/s/[redacted]/slow-symbol-in-pathological-file.mp4?dl=0

Restarting Xcode (after a round-trip through Xcode8 to see if it had similar problems) made it fast again.

Steps to Reproduce:
Have a file that is (as the younguns say) totes-redonk large
Have Xcode been running for awhile
command-control click to jump to a symbol (in this case a method implementation)  The source is about line 5723, and destination at line 5867.

Expected Results:
Jumps to the location instantaneously

Observed Results:
It takes a noticable amount of time 3-5 seconds

Version:
Version 9.0 beta 2 (9M137d)
10.12.5 (16F73)

Notes:
Xcode 8 was instantaneous.  Returning to Xcode9 it's fast again.  So I guess there's might be some "Xcode's been in use for a while and stuff is building up somewhere".

I did not try it with a smaller file when misbehaving, to see if it was the large-file aspect, or just something else being pokey.

Configuration:

Comments


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