[swift-users] stack trace of Swift executable
Greg Parker
gparker at apple.com
Tue May 2 16:43:30 CDT 2017
That doesn't look symbolicated. If it were symbolicated, and the build used -g, you would have a file and line number for the main+345 frame.
> On May 2, 2017, at 2:31 PM, Nick Snyder via swift-users <swift-users at swift.org> wrote:
>
> In practice, I would need the stack trace first to figure out how to reproduce the issue, so lldb doesn't really help.
>
> How would I go about symbolicating this further on macOS (Xcode or otherwise)?
>
> From reading the docs it seems like the crash report I get is already completely symbolicated:
> https://developer.apple.com/library/content/technotes/tn2151/_index.html#//apple_ref/doc/uid/DTS40008184-CH1-SYMBOLICATION-_DETERMINING_WHETHER_A_CRASH_REPORT_IS_SYMBOLICATED <https://developer.apple.com/library/content/technotes/tn2151/_index.html#//apple_ref/doc/uid/DTS40008184-CH1-SYMBOLICATION-_DETERMINING_WHETHER_A_CRASH_REPORT_IS_SYMBOLICATED>
>
> On Tue, May 2, 2017 at 1:21 AM, Alex Blewitt <alblue at apple.com <mailto:alblue at apple.com>> wrote:
> If you can reproduce it, and run it under lldb, it will print the source line for you:
>
> $ lldb .build/debug/main
> (lldb) target create ".build/debug/main"
> ruCurrent executable set to '.build/debug/main' (x86_64).
> (lldb) run
> Process 19013 launched: '/private/tmp/main/.build/debug/main' (x86_64)
> Hello, world!
> fatal error: unexpectedly found nil while unwrapping an Optional value
> 2017-05-02 09:17:11.351608+0100 asdf[19013:54205130] fatal error: unexpectedly found nil while unwrapping an Optional value
> Current stack trace:
> 0 libswiftCore.dylib 0x00000001002c1160 swift_reportError + 125
> 1 libswiftCore.dylib 0x00000001002ddac0 _swift_stdlib_reportFatalError + 60
> 2 libswiftCore.dylib 0x00000001000ce260 specialized specialized StaticString.withUTF8Buffer<A> ((UnsafeBufferPointer<UInt8>) -> A) -> A + 342
> 3 libswiftCore.dylib 0x0000000100249120 partial apply for (_fatalErrorMessage(StaticString, StaticString, file : StaticString, line : UInt, flags : UInt32) -> Never).(closure #2) + 109
> 4 libswiftCore.dylib 0x00000001000ce260 specialized specialized StaticString.withUTF8Buffer<A> ((UnsafeBufferPointer<UInt8>) -> A) -> A + 342
> 5 libswiftCore.dylib 0x00000001001fbd00 specialized _fatalErrorMessage(StaticString, StaticString, file : StaticString, line : UInt, flags : UInt32) -> Never + 96
> 6 main 0x0000000100001340 say(message : String?) -> () + 248
> 7 main 0x00000001000011e0 main + 328
> 8 libdyld.dylib 0x00007fffb444d234 start + 1
> Process 19013 stopped
> * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
> frame #0: 0x00000001001fbd60 libswiftCore.dylib`function signature specialization <preserving fragile attribute, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, file : Swift.StaticString, line : Swift.UInt, flags : Swift.UInt32) -> Swift.Never + 96
> libswiftCore.dylib`function signature specialization <preserving fragile attribute, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, file : Swift.StaticString, line : Swift.UInt, flags : Swift.UInt32) -> Swift.Never:
> -> 0x1001fbd60 <+96>: ud2
> 0x1001fbd62 <+98>: nopw %cs:(%rax,%rax)
>
> libswiftCore.dylib`protocol witness table accessor for <A> Swift.AnySequence<A> : Swift.Sequence in Swift:
> 0x1001fbd70 <+0>: pushq %rbp
> 0x1001fbd71 <+1>: movq %rsp, %rbp
>
> (lldb) bt
> * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
> * frame #0: 0x00000001001fbd60 libswiftCore.dylib`function signature specialization <preserving fragile attribute, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, file : Swift.StaticString, line : Swift.UInt, flags : Swift.UInt32) -> Swift.Never + 96
> frame #1: 0x0000000100001438 main`say(message=nil) -> () at main.swift:5
> frame #2: 0x0000000100001328 main`main at main.swift:8
> frame #3: 0x00007fffb444d235 libdyld.dylib`start + 1
> frame #4: 0x00007fffb444d235 libdyld.dylib`start + 1
>
> There is a symbolication tool available for Linux in the ~/swift/utils/symbolicate-linux-fatal, and Xcode can do the same symbolication for you as well.
>
> Alex
>
>> On 28 Apr 2017, at 22:28, Nick Snyder via swift-users <swift-users at swift.org <mailto:swift-users at swift.org>> wrote:
>>
>> I have a simple main.swift that looks like this:
>>
>> ```
>> print("Hello, world!")
>> let x: String? = nil
>>
>> func say(message: String?) {
>> print(x!) // intentional crash
>> }
>>
>> say(message: x)
>> ```
>>
>> Running this results in the crash
>>
>> ```
>> $ swift build && ./.build/debug/hello
>> Hello, world!
>> fatal error: unexpectedly found nil while unwrapping an Optional value
>> Current stack trace:
>> 0 libswiftCore.dylib 0x0000000110120130 swift_reportError + 129
>> 1 libswiftCore.dylib 0x000000011013cb50 _swift_stdlib_reportFatalError + 60
>> 2 libswiftCore.dylib 0x000000010ff2d250 specialized specialized StaticString.withUTF8Buffer<A> ((UnsafeBufferPointer<UInt8>) -> A) -> A + 342
>> 3 libswiftCore.dylib 0x00000001100a7e90 partial apply for (_fatalErrorMessage(StaticString, StaticString, file : StaticString, line : UInt, flags : UInt32) -> Never).(closure #2) + 109
>> 4 libswiftCore.dylib 0x000000010ff2d250 specialized specialized StaticString.withUTF8Buffer<A> ((UnsafeBufferPointer<UInt8>) -> A) -> A + 342
>> 5 libswiftCore.dylib 0x000000011005a9a0 specialized _fatalErrorMessage(StaticString, StaticString, file : StaticString, line : UInt, flags : UInt32) -> Never + 96
>> 6 hello 0x000000010fee6200 main + 345
>> 7 libdyld.dylib 0x00007fffe0375234 start + 1
>> Illegal instruction: 4
>> ```
>>
>> From the crash, how do I map back line 6 to an actual line in main.swift?
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>
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