I have three iOS projects:
First one - 35k Swift LOC, Swift 2.1 (or 2.0?), compiled using Xcode 7.2.3
Second one - 15k Swift LOC, Swift 2.3, compiled using Xcode 8.2.1
Third one - 15k Swift LOC, Swift 3.0, compiled using Xcode 8.2.1
The compile times for all of these are abysmal (10+ minutes for a clean build), and the development on each one of these is slowing to a crawl.
I have already tried:
Using Whole Module Optimization
Changing C Dialect to compiler default
Analyzing build times for the project and optimizing bottlenecks (a few methods that took 6-10s to compile with array concatenation, nil coalescing operators and such), which shaved like 15 seconds - completely unnoticeable difference
HEADERMAP_USES_VFS = YES
A few other I don't remember now
I'm working on a Mac mini Late 2014 with an SSD, 8GB RAM & 2.6ghz i5, if that matters.
Anyone knows what might cause that, what to do with that or even any workarounds for now? From what I've read on SO and other places, it seems like an unresolved compiler issue.
EDIT: Yes, I'm using Cocoapods for dependencies. I'll try moving to Carthage and see what happens.
Try set the following in Build Settings as a workaround. I am assuming you have just one Target.
Set the Build Active Architecture Only to Yes.
Set Optimization Level to None [-Onone]
Add User-Defined setting called "SWIFT_WHOLE_MODULE_OPTIMIZATION" with the value "YES"
Empty your derived data and build.
You can also then use this tool to analyze any slow compiling Swift files: https://github.com/RobertGummesson/BuildTimeAnalyzer-for-Xcode
I was experiencing build times that were taking 6-7 minutes. I moved away from Cocoapods and started using Carthage which helped for clean builds. Even then builds were still taking 3 minutes. The biggest improvement came with the steps I mentioned above.
Update
Instead of adding the User-Defined setting, on your Debug build set the Optimization Level to 'Fast, Whole Module Optimization'. Then in Other Swift Flags for your debug build add '-Onone'.
It's an open issue on swift's site: https://bugs.swift.org/browse/SR-6037
Hopefully they'll fix it soon.
Related
I am posting this after reading many similar posts on here regarding this issue and none of the solutions that worked for other people not working...
Xcode Version 8.3.3 (8E3004b)
Swift 3.1
Things I tried
Deleting Derived Data folder
Deleting Workspace File
Cleaning Build Folder
Cleaning Build
Reinstalled Xcode (after complete removal)
I also looked for Swift Issues:
Removed all concatenating strings
Cleaned up Swift arrays and dictionaries
Added Whole module optimizations
This all started happening after last Xcode update of 8.3.3. My project was compiling within seconds and now I have to wait at least 15 mins for it to index, then 5 minutes to compile after everything I change even something small in code.
When Building, it get stuck in "Compiling Swift source files". Is there way for me to look in to where it is actually getting stuck?
BIG UPDATE
I tried pretty much everything. Read every article, post, ect. NOTHING worked. My project was created right after 10.0.
Solution
Creating a new project and copying each file worked! It used to take 8-9 minuted to build. Now less than 2 seconds!
Apple knows about this problem, and says that Xcode 9 beta will perform much better. Note that if you don't want to update to Swift 4, you can continue compiling in Swift 3 mode using Xcode 9. The big limitation is that you won't be able to submit your project to the App Store until Xcode 9 goes final.
Also, Xcode 9 contains a new build system. You don't get it by default: you have to turn it on for this project. Choose File > Project Settings and switch the pop-up menu to New Build System (Preview). This is experimental, but it will be the default build system eventually, so it would be interesting to know whether this makes an appreciable difference.
If you don't want to update to Xcode 9 beta, you will just have to do a binary search: comment out all your code and start adding it back, piece by piece, until you find that piece that's causing the trouble.
The best way to work this out is to find what out what the build is doing while compiling your code. This is a really useful tool to use: https://github.com/RobertGummesson/BuildTimeAnalyzer-for-Xcode
When you run this tool it will show you what methods are taking the longest to compile, and then you fix those. Once you have done that, you can also try the answer I gave here to decrease the build times: Extremely long compilation times with Swift in Xcode
I like Apple and the things they do, but Swift... OH GOD!
I have a problem with `Swift` compile time.
Configuration:
MacBook Pro (Retina, 13-inch, Mid 2014)
2,6 GHz Intel Core i5
8 GB 1600 MHz DDR3
SSD 256 (up to 800 MB/s)
1k classes
10 pods
Compile time: 3 min.
Looks like for "new best and amazing swift, the dream" this configuration is not enough and it works like Google Chrome - InfiniteLoop(find free memory - eat)
I tried various methods to speed up the compile time:
Set HEADERMAP_USES_VFS to YES (no change)
Set Build Settings / Architectures / Build Active Architecture Only
to YES (some improvement)
Set defaults write com.apple.Xcode PBXNumberOfParallelBuildSubtasks 4 (8)
(sometimes it's become even worse)
Set optimisation level to -Onone (no major improvement)
Set debug information format - DWARF instead of DWARF with dSYM File
Disable Find implicit dependencies from your scheme (no major
improvement)
Created a new project and moved all files to the new one (takes too long and give small time improvement)
Change compilator from default to others available (even worse)
Strict rules on how to write fast compiled Swift code (below more details)
I've found a few posts where people describe the same problem: here and here
I guess everyone is waiting for new Xcode 8.2 beta 2 where:
Xcode will not rebuild an entire target when only small
changes have occurred. (28892475)
But this is only partially true, I still have long compile time - moved from 6-12 minutes to 3-8. Detailed description of this can be found here and here
Also, I followed all these rules during code writing:
Chained function reduction
Unwrapping the optionals
Implicit typing for an object (dictionary especially)
Avoiding ?? operator (this one extremely hungry!!)
Avoiding ?: operator
In othe words, don't use any "new cool features" because you'll wait for ages.
One more try - is a workaround described here:
Go to Product -> Scheme -> Edit Scheme. Select Build in left side
column and uncheck "Find implicit dependencies" But this flag should
remain checked when you are building the project for the first time.
But, this workaround isn't what I'm looking for and this is also can be as a temporary solution.
Swift is a pain not because it's hard to write, but because it's hard to use (at least on some machines).
For comparison: I have a project on Objective-C with 2k classes, and 11 pods - clean compile time is ~30 seconds.
Also I found a lot of opened bugs on swift performance:
SR-2461
SR-1465
SR-1707
SR-663
and many others, the list is too long, and some of them were opened a few years ago
My question is:
Does anyone have any solution on improving compile time for Swift?
This issue has been extremely frustrating for me as well. We've tried several of the solutions you've mentioned and none of them worked.
The one thing that made a significant improvement in compilation time is:
Turning on the Whole Module Optimization while adding -Onone in Other Swift Flags.
See this - Speed Up Swift Compilation
I'm using Swift 3 with Xcode 8.3.
We improved our compile times a lot by using Carthage instead of Cocoapods to include third party libraries.
It's likely you have code optimisation switched on, whilst this is a must for building your release version, for dev builds it isn't particularly important.
What code optimisation does is exactly what it says, it optimises your code to make the end binary that is produced smaller. It does things such as rename variables/methods to single characters etc... Like I said you obviously want this when submitting to the app store but you might not care if the app is larger whilst developing it.
You can turn off code optimisation for development builds by going to Project Settings > Build Settings, searching 'optim', under Swift Compiler - Code Generation set Optimization Level to None [-Onone] for Debug builds.
This should significantly improve your build times.
WHOLE MODULE OPTIMIZATION WITH NO DEBUGGING RESTRICTIONS
Just add SWIFT_WHOLE_MODULE_OPTIMIZATION as an user-defined setting with the value YES and your compile times should improve a lot.
This fix was introduced by the developers at Zalando. Shout out to them.
https://jobs.zalando.com/tech/blog/improving-swift-compilation-times-from-12-to-2-minutes/?gh_src=4n3gxh1
This Issue Occurred On A SpriteKit Xcode Project
I have an issue with Swift where, once my project reaches a certain level of complexity where I have tons of classes and methods around, my autocompletion breaks so that "Jump To Definition" ceases to work and my IDE is reduced to the usefulness of a basic TextEditor/Notepad.
My code's color will change to white completely, which causes a lot of strain on my eyes, and this seems to only happen when I remove and add large blocks of code as I watch my CPU activity climb up to 75% usage on all CPU cores.
I think this started happening when I switched the target iOS from 9.3 over to 8.0. Is this an issue with the compiler trying to interpret old Swift syntax?
I also will have cases where I wait two minutes for minor changes to compile, only for the build to fail due to "Linker command failed with exit code", which is easily fixed by compiling twice.
Here's my specs:
OS X 10.11.4
Core i7 Skylake 4.0GHz
16 GB DDR4 RAM
256GB SSD
I'm thinking about building a system running OS X with dual processors which might alleviate the issue, since it can take upwards of 2 minutes just to compile code that's different by 1 line.
Okay, I found one solution which resolved my issue.
Remove All Emojis From Variable Names & .Swift File Names
Contrary to Apple's official Swift 2.0 textbook, DO NOT use ANY kind of Emoji's for things like Variable Names and Swift File Names UNLESS you know that the emoji you're using is a very old emoji (but even then, I wouldn't recommend it).
After opening my project in AppCode, AppCode had unicode problems with file names such as: foobar🔵.swift. It was very buggy and it would break Xcode later if I opened and saved a project with pre-existing emojis in AppCode.
So avoid using emojis in your code unless it's for strings like:
let someString = "⬛️🗡💣📚"
Welcome to Swift! Great language, awful tooling.
Joking aside, there are a couple of issues at play here. First off, syntax highlighting disappears when SourceKit crashes. SourceKit is the library which parses Swift on-the-fly so that Xcode can do things like indexing, syntax highlighting and code completion. It's a lot better than it used to be (using Swift 1.0 in Xcode was almost comical at times), but it's still far from perfect. Until SourceKit improves, you won't see much difference.
As for your build times, it's worth trying something like the Swift Build Time Analyzer to see which functions are taking a particularly long time to compile. I recently halved the compile time of the project I work on by removing all lazy vars set via closures. A recent compiler change made type inference for these sorts of closures incredibly slow, so each one was taking ~6 seconds to compile.
I have updated my Swift project to version 1.2 and the build times have been improved after using Build Setting option Whole Module Optimization=Yes. But even if there is a small change in Swift file the entire Objective C files are getting compiled when I tried to build. Is there any other optimization option Available? I'm using Xcode 6.3.2
Why don't you only enable Whole Module Optimization in your Release build and leave it off for Debug. That way you won't have to wait long for compilation and testing builds but your users still get the benefit of the speeds of Whole Module Optimization.
One of the long anticipated features of Swift 1.2/Xcode 6.3 is incremental builds. They worked fine for me until recently, but now almost every time I change even a single line of code it does full rebuild.
I tried restarting Xcode, computer, cleaning derived data, but to no avail. Googling doesn't seem to reveal anything.
Does anyone else have this problem? How do I fix it?
I think that this is what you searching for
I am not this is a source of the problem. According to https://developer.apple.com
Swift Performance
A new compilation mode has been introduced for Swift called Whole Module Optimization. This option optimizes all of the files in a target together and enables better performance (at the cost of increased compile time). The new flag can be enabled in Xcode using the “Whole Module Optimization” build setting or by using the swiftc command line tool with the flag -whole-module-optimization. (18603795)