unable to execute command: Segmentation fault: 11 swift frontend command failed due to signal (use -v to see invocation)

Question

I have an iOS swift program that compiles and runs fine on Xcode Beta2. When I downloaded beta4, I got a few syntax errors for the new swift language which I corrected. I now get this error:

<unknown>:0: error: unable to execute command: Segmentation fault: 11
<unknown>:0: error: swift frontend command failed due to signal (use -v to see invocation)

The problem is that it does not tell me where this error is so that I can further troubleshoot it. Where can I type -v in order to "see the invocation" and troubleshoot further? Without this, there is absolute no way to figure out the problem. Thanks in advance.

Answer 1

Here's how I was able to find out what the problem was:

1. Click on the issue in the issue navigator (⌘ + 4, then click on the line with the red ! at the start)
2. At the bottom of the file that appears, there should be a line that says something like:

1. While emitting IR SIL function @_TToZFC4Down8Resource12getInstancesfMS0_U__FTSS6paramsGVSs10DictionarySSPSs9AnyObject__9onSuccessGSqFGSaQ__T__7onErrorGSqFT5errorCSo7NSError8responseGSqCSo17NSHTTPURLResponse__T___T_ for 'getInstances' at /path/to/file.swift:112:5

3. The location where your error occurred is at the end of that line. (In this case, on line 112 of file.swift in getInstances).

Answer 2

I was trying to add the PayPal framework to my iOS Project (Xcode 7.2 and Objective C language). When building it did not throw any error, but when I tried to archive the Project and make the IPA, I was getting that error

unable to execute command: Segmentation fault: 11

Screenshot:

After struggling for a long time, I disabled the Bitcode in Project's Target > Build Settings > Enable Bitcode. Now the project can be archived. Please check the following screenshot.

Answer 3

Can't really give a straight solution on this (although I'm sure it's an Apple bug), but I just came across the exact same error message and happen to solve it. Here's what I did:

In General

1. Comment out recently changed Swift code (check commits) until the app compiles again
2. Command-click each called method in the failing line and check if there could be an ambiguity

My Example

In my case (I was using the XMPPFramework written in Objective-C) the failing code looked like this:

for roomMessage: XMPPRoomMessage in self.messages {
    let slices = split(roomMessage.nickname(), { $0 == "_" }, allowEmptySlices: false)
}

Once I replaced roomMessage.nickname() with "0_test" the code didn't fail any more. So I command-clicked the method nickname() (twice) and here's what I saw:

My guess was that the Swift 1.1 compiler has problems with figuring out which method to call if the exact type of an object is not clear. So I made the type of roomMessage explicit and got another error which I fixed by removing the braces behind the nickname() method call. This made my app build again. Here's the working code:

for roomMessage: XMPPRoomMessageCoreDataStorageObject in self.messages {
    let slices = split(roomMessage.nickname, { $0 == "_" }, allowEmptySlices: false)
}

I hope this helps someone out there to investigate the issue more quickly than I did.

Answer 4

I also had the same problem,

1. when I cleaned the derived data
2. Remove all removed derived data from Trash as well.
3. Stop Xcode, restart it and clean build

It should be fixed now.

Answer 5

In my case this error because I use Class name for variable

var MYClass : MYClass {
    get {
        return.....
    }
}

And this fixes my problem

var myClass : MYClass {
    get {
        return.....
    }
}

Answer 6

My problem was that I tried to mimic static variables with the so-called module approach (the Module design pattern). So, I had something like that (just a simple static reference to an operation queue declared at the level of a swift file):

let globalQueue: NSOperationQueue = {
    let queue = NSOperationQueue()
    queue.suspended = false
    queue.maxConcurrentOperationCount = NSOperationQueueDefaultMaxConcurrentOperationCount
    return queue
}()

So, that worked fine in Xcode 6.x.x, but ceased to compile in Xcode 7beta. Just want you guys to be aware of it. P.S. In general, I managed to find out what was wrong from the logs (see the screenshot attached). Hope this saves you some time.

Answer 7

I got Segmentation fault when I called a protocol function the same protocols extension.

I had a code something in the line with this:

protocol Rotatable {
    func rotate() -> Self
}

extension Rotatable {
    func rotate(steps: Int) {
        for _ 0..<steps { self.rotate() }
    }
}

When I later made an object and declared that it would follow the Rotatable protocol I got Segmentation fault 11 and the program crashed.

Ex: this would cause Segmentation fault and crash Xcode

struct SomeStruct : Rotatable {

}

If I however first implemented the function rotate() in SomeStruct and then afterwards declared that it conformed to Rotatable there where no problem.

Answer 8

I had a similar today and tried the steps described here including removing files I had recently modified. Nothing seemed to work. I tried something that had been suggested when SourceKit would crash in Xcode.

I when into the derived data directory and deleted everything. The location is listed under "Preferences -> Locations -> Derived Data" There is an arrow icon right next to the path which opens finder with that directory selected. Select all the directories inside and delete them. Close Xcode and Reopen it. That made the problem disappear for me.

I think that some intermediate file is getting corrupted and the compiler does not know how to handle it.

Answer 9

I get this error because a silly mistake!!

in a class I defined

var url: String!?

:)

So it seems that this description is a multiple & generic error for a lot of reasons!!

Answer 10

This can happen as well if you are porting Objective-C code to Swift and you move an objective C protocol to swift. If you leave off the @objc at the protocol definition and you still have Objective-C code that uses that protocol you can get this error.

The solution in that case is adding @objc to the protocol

protocol MyPortedProtocol {}

changes to

@obcj protocol MyPortedProtocol {}

Also make sure any classes that implement this protocol add @objc to the methods

Answer 11

I did answer in "Swift compiler segmentation fault when building"

I had this error too, and i fixed like this:

check your project and find out which files are using twice and remove one, or delete all and re-add them.

Errors in my xCode

:0: error: filename "AttributedString.swift" used twice: '/Users/.../CNJOB/CNJOB/AttributedString.swift' and '/Users/.../CNJOB/CNJOB/AttributedString.swift'

:0: note: filenames are used to distinguish private declarations with the same name

:0: error: filename "APIClient.swift" used twice: '/Users/.../CNJOB/CNJOB/APIClient.swift' and '/Users/.../CNJOB/CNJOB/APIClient.swift'

:0: note: filenames are used to distinguish private declarations with the same name

Command /Applications/Xcode 3.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc failed with exit code 1

Answer 12

For me it's caused by adding the swift files to different targets (today extension in my case).

Answer 13

I forgot to add one @end after @implementation in a .m file that had multiple classes in it. Something like:

@implementation Adjust

@end

@implementation Data //@end For this class was missing 


@implementation Create

@end

Answer 14

I got this bug because of line

self.textView.inputAccessoryView = self.toolbarItems;

If you delete it the error will gone.

My steps: 1)

1. Deleted Derived data
2. Cleared build folder Didn't help
3. Copied class files to another folder as backup and commented everything in this class. Error gone.
4. Commented code blocks one by one until build was success.

Answer 15

For me the problem was mixing Generics, Extensions, and @objc.

It turns out Xcode doesn't like having @objc inside extensions of generic classes:

class FaultyClass<T: TypeValidator>: UIControl where T.ItemType == String {
}

extension FaultyClass: UITextFieldDelegate {
    func textFieldDidEndEditing(_ textField: UITextField) {
    }
}

The above code gives the error @objc is not supported within extensions of generic classes. So I moved the method to the class itself but didn't delete the empty extension. This got rid of the error but when I compiled the project I got the segmentation fault.

The solution was to move UITextFieldDelegate to the class declaration.

class GoodClass: <T: TypeValidator>: UIControl, UITextFieldDelegate where T.ItemType == String {

// MARK: - TextFieldDelegate
    func textFieldDidEndEditing(_ textField: UITextField) {
    }
}

Answer 16

My problem was in methods signatures:

func setCategory(categoryId: Int?, subcategoryId: Int?) -> FilterSettings {

func changeCategory(categoryId: Int?, subcategoryId: Int?, handler: @escaping (Int) -> ()) {

I don't get why compiler cannot handle such declarations.

Answer 17

In my case it was because of an inappropriate inout in the function parameters. So I suggest you to look for that as well.

Answer 18

For me it was something similar to what @LuisCien described in this answer https://stackoverflow.com/a/42803582/4075379

I didn't have any generics or @objc tags, but it was these lines of code that were causing the segmentation fault:

public extension CGFloat {
    /// Whether this number is between `other - tolerance` and `other + tolerance`
    func isEqual(to other: CGFloat, tolerance: CGFloat) -> Bool {
        return (other - tolerance...other + tolerance).contains(self)
    }
}

i.e. an extension on a primarily Objective-C primary type? Very luckily, I was able to delete those lines because the project wasn't using anymore. That fixed the issue.

Answer 19

Dumb mistake. I referred to self in a Class method:

public class func FunctionName() -> UIImage {        
    let bundle = Bundle.init(for: type(of: self))
    ...
}

Answer 20

I run into this problem when building some legacy code whaich was not adapted for latest Swift versions.

Segmentation fault: 11

When you open Report navigator it contains some context like:

1.  Apple Swift version 5.3.2 (swiftlang-1200.0.45 clang-1200.0.32.28)
2.  While evaluating request IRGenSourceFileRequest(IR Generation for file "/Users/alex/Downloads/NSURLProtocolExample-Swift_complete/NSURLProtocolExample/AppDelegate.swift")
3.  While emitting IR SIL function "@$s20NSURLProtocolExample11AppDelegateC11applicationAD29didFinishLaunchingWithOptionsSbSo13UIApplicationC_So12NSDictionaryCSgtF".
 for 'application(application:didFinishLaunchingWithOptions:)' (at /Users/alex/Downloads/NSURLProtocolExample-Swift_complete/NSURLProtocolExample/AppDelegate.swift:17:3)
0  swift                    0x000000010b2d3615 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37
1  swift                    0x000000010b2d2615 llvm::sys::RunSignalHandlers() + 85
2  swift                    0x000000010b2d3bcf SignalHandler(int) + 111
3  libsystem_platform.dylib 0x00007fff2039bd7d _sigtramp + 29
...

To solve this issue:

1. comment the pointed line (line 17 in AppDelegate.swift)
2. Build and fix all others issues
3. uncomment line from step 1

Answer 21

Swift 5 Very Easy And Smooth Solution

1-    Just check your last added Extension / Code / Folder File before then this issue occur
2-    Just Commit the code or save that code 
3-    Clean and Build & DONE :-) 

Happy Coding

Answer 22

I ran into a similar problem when switching from beta2 to beta4.

Clean

then

Build