[lldb-dev] Quite annoying assertion

[Andrey Zaytsev]

I just got it. 

NSArray *arr = [NSArray array];

following code will trigger assertion:

SBValue res = frame.EvaluateExpression("[arr respondsToSelector:@selector(objectEnumerator)]");
if (res.IsValid()) {
    res.GetTypeName(); //  <-- here
}

backtrace:
#0  0x00007fff817aa9ce in __semwait_signal_nocancel ()
#1  0x00007fff817aa8d0 in nanosleep$NOCANCEL ()
#2  0x00007fff818073ce in usleep$NOCANCEL ()
#3  0x00007fff81826a00 in abort ()
#4  0x00007fff818139bc in __assert_rtn ()
#5  0x00000001002e5f43 in lldb_private::ClangASTType::GetTypeNameForQualType ()
#6  0x00000001002e60f1 in lldb_private::ClangASTType::GetConstTypeName ()
#7  0x0000000100259bf9 in lldb_private::ValueObjectConstResult::GetTypeName ()
#8  0x0000000100189607 in lldb::SBValue::GetTypeName ()
#9  0x000000010006f29e in jetcidr::EvaluatedValue2LLDBValue (pair=@0x101f86a78, lldb_val=0x1034c5050) at ResponseFactory.h:52
#10 0x000000010007b7cc in jetcidr::ResponseFactory::EvaluateExpression (this=0x103407910, pair=@0x101f86b20) at /Users/zajac/Projects/ULTIMATE/CIDR/LLDBProtobufFrontend/LLDBProtobufFrontend/src/ResponseFactory.cpp:92
#11 0x000000010006b8f1 in jetcidr::ProtobufHandler::HandleEvaluateExpression (this=0x1031001d0, req=@0x1034ade10) at /Users/zajac/Projects/ULTIMATE/CIDR/LLDBProtobufFrontend/LLDBProtobufFrontend/src/ProtobufHandler.cpp:156
#12 0x000000010006c2cf in jetcidr::ProtobufHandler::ProcessMessage (this=0x1031001d0, req=@0x101f86c50) at /Users/zajac/Projects/ULTIMATE/CIDR/LLDBProtobufFrontend/LLDBProtobufFrontend/src/ProtobufHandler.cpp:236
#13 0x000000010006c620 in __HandleHasBytesAvailable_block_invoke_0 (.block_descriptor=<value temporarily unavailable, due to optimizations>) at /Users/zajac/Projects/ULTIMATE/CIDR/LLDBProtobufFrontend/LLDBProtobufFrontend/src/ProtobufHandler.cpp:261
#14 0x00007fff8176cfbb in dispatch_barrier_sync_f ()
#15 0x000000010006c42f in jetcidr::ProtobufHandler::HandleHasBytesAvailable (this=0x1031001d0, r_source=0x103100000) at /Users/zajac/Projects/ULTIMATE/CIDR/LLDBProtobufFrontend/LLDBProtobufFrontend/src/ProtobufHandler.cpp:252
#16 0x00000001000699b1 in __StartHandlingClient_block_invoke_05 (.block_descriptor=<value temporarily unavailable, due to optimizations>) at /Users/zajac/Projects/ULTIMATE/CIDR/LLDBProtobufFrontend/LLDBProtobufFrontend/src/ProtobufServer.cpp:76
#17 0x00007fff817533f3 in _dispatch_source_invoke ()
#18 0x00007fff817527b4 in _dispatch_queue_invoke ()
#19 0x00007fff817528dc in _dispatch_queue_drain ()
#20 0x00007fff81752734 in _dispatch_queue_invoke ()
#21 0x00007fff817522de in _dispatch_worker_thread2 ()
#22 0x00007fff81751c08 in _pthread_wqthread ()
#23 0x00007fff81751aa5 in start_wqthread ()

This happened for me only in 32-bit mode when running app in simulator and attaching to process by pid.
But(!): 

(lldb) p [arr respondsToSelector:@selector(objectEnumerator)]
error: Execution was interrupted, reason: EXC_BAD_ACCESS (code=1, address=0xffffffff).
The process has been returned to the state before execution.

After this lldb won't crash.

What am I doing wrong?

On 09.08.2011, at 2:38, Enrico Granata wrote:

> Would you be able to provide example commands that trigger this?
> This looks like some of your types are not completed, but it's hard to tell which ones and why without something reproducible
> 
> On Aug 8, 2011, at 3:34 PM, Andrey Zaytsev wrote:
> 
>> Hello everyone!
>> I'm very often getting this assertion when evaluating some sort of expressions:
>> 
>> Assertion failed: (!isNull() && "Cannot retrieve a NULL type pointer"), function getCommonPtr, file /SourceCache/lldb/lldb-69/llvm/tools/clang/include/clang/AST/Type.h, line 404.
>> 
>> This assertion fires every time I'm evaluating something like this: "[0x12345.. someSelector]". I'm stuck with it because I need values of this kind of expressions to display ns-collections.
>> 
>> Thanks for your consideration.
>> _______________________________________________
>> lldb-dev mailing list
>> lldb-dev at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> 
> 
> Thanks,
> Enrico Granata
> ✆ 408.974.5572 | ✉ egranata@.com
> 
> 
> 
> 

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