[llvm-dev] Undefined behaviour in command line parser

[Lorenzo Laneve via llvm-dev]

Done, I added as much info as I could that describes how I got that behavior.

> On Mar 27, 2016, at 7:40 PM, Renato Golin <renato.golin at linaro.org> wrote:
> 
> Hi Lorenzo,
> 
> Thanks for the report. Can you create a new entry in Bugzilla? With
> steps to reproduce (command line options, etc) and how you're getting
> the value of the triple (debugger?).
> 
> http://llvm.org/bugs/
> 
> cheers,
> --renato
> 
> On 27 March 2016 at 17:15, Lorenzo Laneve via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
>> In these days I’ve integrated llc code into my compiler.
>> 
>> I had an undefined behaviour because when
>> cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion)
>> is called, the modules I give to the code in input to compile got somehow
>> “corrupted" by this function.
>> It is definitely an undefined behaviour because every debug I do, modules
>> gets different changes, producing different assertions every run:
>> 
>> - Target triple string gets changes with null characters
>> (“\0\0\0\0\0\0\0\0\0\0\0”), or other values that have nothing to do with an
>> llvm triple
>> - Head of the function list contained in the module becomes NULL (I said
>> functions but maybe other components may be nullified as well)
>> 
>> I tried to see where the modules change, and I figured out that 6/10 times
>> the target triple is ok before that instruction, then it takes weird changes
>> after it.
>> The problem is that function because when I removed it, everything worked
>> fine.
>> 
>> I didn't figure out how that function may change modules that way, so I just
>> report this bug here.
>> 
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