Hi Max,


> On May 7, 2017, at 4:24 AM, Max Leske <maxleske at gmail.com> wrote:
> 
> Hi,
> 
> I'm trying to store an image segment with the latest pharo.cog.spur VM (32 bits) but keep failing. The segment should produce a file of around 60 MB. With an old V3 VM this is no problem at all. There, the WordArrayForSegment instance has a size of 4094179 but with the new VM I always run out of space because the primitive returns nil and, therefore, the word array size is constantly being increased.
> 
> I've built a debug VM and am stepping through the code but I don't have a clear understanding of everything that's happening. The failure happens on line 46626 of gcc3x-cointerp.c:
> 
> newOop = (copy - segStart) / 8;
> if (newOop > (identityHashHalfWordMask())) {
>    return PrimErrLimitExceeded;  // <--------------- failure
> }
> 
> What I don't understand, for example, is why "newOop" is checked against "identityHashHalfWordMask()" and not against the segment end ("endSeg"). Here's a list of the current values of the variables upon failure:
> 
> objOop    sqInt    180812096
> segAddr    sqInt    494731288
> segStart    sqInt    461176856
> endSeg    sqInt    815841432
> bodySize    usqInt    64
> contextSize    sqInt    335672448
> copy    sqInt    494731288
> hash    sqInt    0
> hash1    sqInt    4194302
> i    sqInt    833574680
> iLimiT    sqInt    833574688
> methodHeader    sqInt    1193471
> newOop    sqInt    4194304
> numMediatedSlots    sqInt    833574688
> numSlots    usqInt    14
> oop    sqInt    142640272
> 
> As you can see, "endSeg" would be more than large enough to hold the object. Is it possible that there's an error here?

Quite possibly.  Why don't you try and debug it in the simulator?  The Smalltalk code is much more comprehensible and is where you'd have to fix it anyway.

> 
> Cheers,
> Max
>