[SR-10635] Crash post migration to xcode 10.2

[swift-ci]

Previous ID	SR-10635
Radar	rdar://problem/50858819
Original Reporter	sohilr (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Attachment: Download

Environment

Crashes on Device only

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, 5.0Regression, RunTimeCrash
Assignee	@slavapestov
Priority	Medium

md5: 7688e6f426119ffdb3f24739144588f6

Issue Description:

We recently migrated to Xcode 10.2.1 from Xcode 10.1 and have started observing crash in libswiftCore.dylib framework. Below are two such stacktraces. We noticed that the crash occurs only for the ipa build via command line. we are unable to reproduce this issue in simulator and can only reproduce it on device.

0 libswiftCore.dylib 0x00000001c15a5c64 swift_getAssociatedTypeWitnessSlowImpl+ 2718820 (swift::MetadataRequest, swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*) + 212
1 libswiftCore.dylib 0x00000001c15a5c64 swift_getAssociatedTypeWitnessSlowImpl+ 2718820 (swift::MetadataRequest, swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*) + 212
2 libswiftCore.dylib 0x00000001c15a4340 swift_getAssociatedTypeWitness + 176
3 libswiftCore.dylib 0x00000001c14392bc OptionSet.intersection+ 1225404 (_:) + 76
4 MobileApp 0x0000000107531890 protocol witness for SetAlgebra.intersection+ 16717968 (_:) in conformance UIRectEdge + 80
5 libswiftCore.dylib 0x00000001c1439528 OptionSet<>.insert+ 1226024 (_:) + 220
6 MobileApp 0x0000000107531944 protocol witness for SetAlgebra.insert+ 16718148 (_:) in conformance UIRectEdge + 68
7 libswiftCore.dylib 0x00000001c145f390 SetAlgebra.init<A>+ 1381264 (_:) + 568
8 MobileApp 0x0000000108e48cb0 protocol witness for SetAlgebra.init<A>+ 43027632 (_:) in conformance NSStringDrawingOptions + 44
9 libswiftCore.dylib 0x00000001c145f6a0 SetAlgebra<>.init+ 1382048 (arrayLiteral:) + 168



0 libswiftCore.dylib 0x00000001c15a5c64 swift_getAssociatedTypeWitnessSlowImpl+ 2718820 (swift::MetadataRequest, swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*) + 212
1 libswiftCore.dylib 0x00000001c15a5c64 swift_getAssociatedTypeWitnessSlowImpl+ 2718820 (swift::MetadataRequest, swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*) + 212
2 libswiftCore.dylib 0x00000001c15a4340 swift_getAssociatedTypeWitness + 176
3 libswiftCore.dylib 0x00000001c1436dbc static _SwiftNewtypeWrapper<>._conditionallyBridgeFromObjectiveC+ 1215932 (_:result:) + 76
4 MobileApp 0x00000001076cac60 protocol witness for static _ObjectiveCBridgeable._conditionallyBridgeFromObjectiveC+ 16723040 (_:result:) in conformance UIActivityType + 80
5 libswiftCore.dylib 0x00000001c15904a4 _bridgeNonVerbatimFromObjectiveCConditional<A>+ 2630820 (_:_:_:) + 236
6 libswiftCore.dylib 0x00000001c133c968 _conditionallyBridgeFromObjectiveC<A>+ 190824 (_:_:) + 268

[belkadan]

@mikeash, @rjmccall, does this sound familiar?

[rjmccall]

Other than that being a type-demangling path, no, it doesn't. Any sort of message along with the crash?

[swift-ci]

Comment by Angelo Di Paolo (JIRA)

Here's a more complete version of the crash from the bug description:

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000
VM Region Info: 0 is not in any region.  Bytes before following region: 4334977024
      REGION TYPE                      START - END             [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      UNUSED SPACE AT START
--->  
      __TEXT                 0000000102628000-0000000102ac0000 [ 4704K] r-x/r-x SM=COW  ...t.app/WalmartTermination Signal: Segmentation fault: 11
Termination Reason: Namespace SIGNAL, Code 0xb
Terminating Process: exc handler [4620]
Triggered by Thread:  0Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libswiftCore.dylib              0x00000001f3d47c64 swift_getAssociatedTypeWitnessSlowImpl+ 2718820 (swift::MetadataRequest, swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*) + 212
1   libswiftCore.dylib              0x00000001f3d47c64 swift_getAssociatedTypeWitnessSlowImpl+ 2718820 (swift::MetadataRequest, swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*) + 212
2   libswiftCore.dylib              0x00000001f3d46340 swift_getAssociatedTypeWitness + 176
3   libswiftCore.dylib              0x00000001f3bdb2bc OptionSet.intersection+ 1225404 (_:) + 76
4   WalmartCore                     0x00000001052a1c74 protocol witness for SetAlgebra.intersection+ 16784500 (_:) in conformance UIRectEdge + 80
5   libswiftCore.dylib              0x00000001f3bdb528 OptionSet<>.insert+ 1226024 (_:) + 220
6   WalmartCore                     0x00000001052a1d28 protocol witness for SetAlgebra.insert+ 16784680 (_:) in conformance UIRectEdge + 68
7   libswiftCore.dylib              0x00000001f3c01390 SetAlgebra.init<A>+ 1381264 (_:) + 568
8   WalmartCore                     0x0000000106bb7ee0 protocol witness for SetAlgebra.init<A>+ 43089632 (_:) in conformance NSStringDrawingOptions + 44
9   libswiftCore.dylib              0x00000001f3c016a0 SetAlgebra<>.init+ 1382048 (arrayLiteral:) + 168

[swift-ci]

Comment by Angelo Di Paolo (JIRA)

Possibility related to this? https://bugs.swift.org/browse/SR-10463

[swift-ci]

Comment by Angelo Di Paolo (JIRA)

Also worth noting about the crash in the ticket description: When distributing an archive, if "Rebuild from bitcode" is checked, we don't get a crash in the build. However, if we do not check "rebuild from bitcode", we see the crash.

[swift-ci]

Comment by Sohil Rupani (JIRA)

I have attached additional crash seen in libswiftCore framework. Unlike other crashes, this one is only noticed in iPhone 5, 10.3.3 / 10.2.1

[slavapestov]

Is the crash always at the same point in the program? Is there any way you could share the source or a binary? It looks like findConformingSuperclass() might be returning null. Any ideas, @DougGregor?

[DougGregor]

I'm wondering if it's the runtime bug fixed by

#24759

which hasn't made it into any release yet. The stack trace looks very, very similar.

[DougGregor]

We believe this was fixed in Xcode 11 based on several fixes in that area. Can you confirm whether it is indeed fixed for you? If not, we have more digging to do.