[Rcpp-devel] Loading a package using Rcpp Modules results in memory corruption

[Douglas Bates]

On Sat, Jan 8, 2011 at 12:45 AM, Dominick Samperi <djsamperi at gmail.com> wrote:
> I checked things under Linux and Windows (using GCC and VC++ DLL's) and the
> same problem occurs at the same place, which is a good sign when it comes to
> memory issues. Basically, the Rcpp::Reference(std::string) constructor that
> is
> part of S4_field, or S4_CppOverloadedMethods constructors fails, depending
> on
> which comes first (whether there are fields or not). This only happens when
> gctorture() is turned on, so R must be clobbering an unprotected SEXP
> somewhere...

Thanks, Dominick. I too have been working on tracking this down and
got to that point.  If you follow a little further you will find that
it is the evaluation of the R function getCurrentErrorMessage in the
Rcpp::Evaluator::run method where things start to go bad, as far as I
can see.  I hope to be able to isolate this today as I need a working
version of lme4a by tomorrow.

> On Fri, Jan 7, 2011 at 9:47 AM, Romain Francois <romain at r-enthusiasts.com>
> wrote:
>>
>> Hmm. I commited 2845 and 2846 today.
>>
>> Anyway, if you see it also with 0.9.0 this means more detective work.
>>
>> Le 07/01/11 15:05, Douglas Bates a écrit :
>>>
>>> On Fri, Jan 7, 2011 at 5:34 AM, Romain Francois
>>> <romain at r-enthusiasts.com>  wrote:
>>>>
>>>> Le 05/01/11 18:52, Douglas Bates a écrit :
>>>>>
>>>>> I don't know whether this is through error on my part or because of an
>>>>> "infelicity" in the Rcpp module code but the lme4a package, which now
>>>>> uses Rcpp modules extensively, ends up with some difficult-to-trace
>>>>> memory corruption issues.  Yesterday i finally bit the bullet and ran
>>>>> a test with gctorture(TRUE) and valgrind enabled.  It takes a very
>>>>> long time and results in a segfault when trying to load the package.
>>>>> I enclose the transcript.  I should say that this is using Rcpp_0.9.0
>>>>> from CRAN, not the SVN version of Rcpp.
>>>>>
>>>>> I just got these results this morning (it was running overnight) and
>>>>> haven't looked at the code in Module.cpp and cache.cpp yet.  If it
>>>>> seems likely that the code is beyond me I can try to work out a
>>>>> simpler example that triggers the problem.
>>>>
>>>> Hi Doug,
>>>>
>>>> Sorry for the delay, I'm not fully operational yet.
>>>>
>>>> All this might be related to some code I put in during holidays and did
>>>> not
>>>> have a chance to fully test.
>>>>
>>>> Can you try with rev 2845 and let me know if you still see the problem.
>>>>
>>>> Romain
>>>
>>> Regrettably the problem persists with rev 2845 (which was from
>>> 2011-01-04, is that the one you meant?) but it is also present when
>>> using Rcpp_0.9.0
>>
>>
>> --
>> Romain Francois
>> Professional R Enthusiast
>> +33(0) 6 28 91 30 30
>> http://romainfrancois.blog.free.fr
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>>
>>
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