[swift-users] Swift 4.0 LLDBFrontend Crash

[Edward Connell]

I was able to boil down a repro that has nothing to do with my project, woo
hoo!
Put a break at the print statement and run. When it hits the break point
LLDBFrontend crashes.
The do/catch seems to be necessary to trigger the crash

Swift 4.0 release
Ubuntu 16.04

Ed

----------------------------
import Foundation

public class SomeClass { }

public struct SomeStruct {
  public weak var someClass: SomeClass?
}

do {
  let data = SomeStruct()

  print("break here")
} catch {
  print(String(describing: error))
}


On Fri, Oct 13, 2017 at 10:21 AM, Edward Connell via swift-users <
swift-users at swift.org> wrote:

> Hi Michael,
> Thanks, I created and attached a log for you with "types" and
> "expressions" enabled
> I set a breakpoint right before calling the function that triggers the
> crash, enabled logging, then continued. I was trying to reduce the amount
> of log output to sift through.
>
> This was run with the Swift 4.0 release version
> Let me know if you want me to try anything else.
>
> Thanks, Ed
>
>
>
> On Thu, Oct 12, 2017 at 11:13 AM, Michael Gottesman <mgottesman at apple.com>
> wrote:
>
>> I just added a section to ./docs/DebuggingTheCompiler.rst on how to get
>> enable logging from LLDB.
>>
>> Can you enable the logging there and add file an SR?
>>
>> Michael
>>
>> On Oct 7, 2017, at 11:27 AM, Edward Connell <ewconnell at gmail.com> wrote:
>>
>> Hi Michael,
>> No I am not evaluating an expression or anything. This all worked fine in
>> past builds.
>>
>> I simply set a breakpoint in a function and after stopping while
>> gathering values for the debugger view, it crashes.
>>
>> It doesn't crash in all functions, but it does crash when trying to stop
>> in many different functions.
>> An example function signature where it crashes is (DataView is a concrete
>> struct):
>>
>> public func setupForward(mode: EvaluationMode, inData: DataView, labels:
>> DataView?,
>>                                  outData: inout DataView, backData: inout
>> DataView?) throws { ... }
>>
>> Before calling the function, all of the parameters have valid values that
>> I can examine. But as soon as I step into this function, LLDB crashes with
>> that message. It behaves the same way with other functions that have
>> different signatures.
>>
>> I tried to create a very simple repro case using this signature, but it
>> didn't crash. My project is on GitHub and this can be easily reproduced.
>> The only pain is installing my project on your test machine.
>>
>> Ubuntu 16.04
>> Swift 4.0 release
>> NVidia gpu
>> Netlib https://github.com/ewconnell/Netlib/wiki#installation
>> CLion IDE with Swift plugin
>>
>> 1) do a debug build
>> 2) set a breakpoint at CudaSoftmax.swift:44  or any line in the function
>> 3) run
>> 4) when it stops LLDBFrontend crashes
>>
>> *LLDBFrontend:
>> /home/buildnode/jenkins/workspace/oss-swift-4.0-package-linux-ubuntu-16_04/swift/lib/SILOptimizer/Mandatory/AccessEnforcementSelection.cpp:613:
>> (anonymous namespace)::SourceAccess (anonymous
>> namespace)::AccessEnforcementSelection::getSourceAccess(swift::SILValue):
>> Assertion `isa<AllocStackInst>(address) || isa<SILUndef>(address)' failed.*
>> *Stack dump:*
>> *0. While running pass #10 SILModuleTransform ""Access Enforcement
>> Selection"".*
>>
>>
>> Using the LLDB CLI I am able to stop there. If I try "fr var -O" with
>>
>>    - mode, inData, and labels, it prints their values no problem
>>    - outData and backData gives me a segmentation violation
>>
>> The visible difference is the "inout"
>>
>> Not sure what the problem is. It worked fine in the past.
>>
>> If you can think of an experiment I can try to create a simple repro
>> case, please let me know.
>>
>> Thanks, Ed
>>
>> On Fri, Oct 6, 2017 at 4:34 PM, Michael Gottesman <mgottesman at apple.com>
>> wrote:
>>
>>> It looks like this is failing during guaranteed optimization. Are you
>>> running an expression in the debugger and we are crashing there?
>>>
>>> Michael
>>>
>>> On Oct 6, 2017, at 11:53 AM, Edward Connell via swift-users <
>>> swift-users at swift.org> wrote:
>>>
>>> While trying to debug a Netlib function, LLDB is crashing
>>>
>>> I'm not sure what this assert means.
>>>
>>> *LLDBFrontend:
>>> /home/buildnode/jenkins/workspace/oss-swift-4.0-package-linux-ubuntu-16_04/swift/lib/SILOptimizer/Mandatory/AccessEnforcementSelection.cpp:613:
>>> (anonymous namespace)::SourceAccess (anonymous
>>> namespace)::AccessEnforcementSelection::getSourceAccess(swift::SILValue):
>>> Assertion `isa<AllocStackInst>(address) || isa<SILUndef>(address)' failed.*
>>> *Stack dump:*
>>> *0. While running pass #10 SILModuleTransform ""Access Enforcement
>>> Selection"".*
>>>
>>> It fails every time and the same way in several functions, but not all
>>> functions.
>>> I tried to create a simple repro with the same function signature, but I
>>> can't get the simple case to fail.
>>> A debug build isn't doing whole-module-optimization, so that's not it
>>>
>>> Ideas anyone?
>>>
>>> Who owns the LLDBFrontend?
>>>
>>> Thanks, Ed
>>> _______________________________________________
>>> swift-users mailing list
>>> swift-users at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-users
>>>
>>>
>>>
>>
>>
>
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