[llvm-commits] [llvm] r99400 - in /llvm/trunk: lib/CodeGen/LiveIntervalAnalysis.cpp test/CodeGen/Generic/2010-03-24-liveintervalleak.ll

[Török Edwin]

On 03/26/2010 02:29 AM, Jakob Stoklund Olesen wrote:
> On Mar 25, 2010, at 4:48 PM, Evan Cheng wrote:
> 
>> On Mar 25, 2010, at 4:39 PM, Jakob Stoklund Olesen wrote:
>>
>>> On Mar 25, 2010, at 4:32 PM, Evan Cheng wrote:
>>>
>>>> On Mar 25, 2010, at 4:30 PM, Jakob Stoklund Olesen wrote:
>>>>
>>>>> On Mar 24, 2010, at 6:50 AM, Torok Edwin wrote:
>>>>>
>>>>>> Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
>>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=99400&r1=99399&r2=99400&view=diff
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
>>>>>> +++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Wed Mar 24 08:50:36 2010
>>>>>> @@ -85,8 +85,10 @@
>>>>>> void LiveIntervals::releaseMemory() {
>>>>>> // Free the live intervals themselves.
>>>>>> for (DenseMap<unsigned, LiveInterval*>::iterator I = r2iMap_.begin(),
>>>>>> -       E = r2iMap_.end(); I != E; ++I)
>>>>>> +       E = r2iMap_.end(); I != E; ++I) {
>>>>>> +    I->second->clear();
>>>>>> delete I->second;
>>>>>> +  }
>>>>>>
>>>>>> r2iMap_.clear();
>>>>> I think LiveInterval::clear is broken. I calls VNI->~VNInfo(), but those VNIs can be referenced from multiple intervals.
>>>> Really? Multiple liveinterval's or liverange's?
>>> LiveIntervals.
>>>
>>> Is a VNI supposed to belong to only one LiveInterval? I don't know any concrete examples where that is not the case, but a lot of funny stuff is going on when coalescing.
>> I don't think VNI should be shared between liveinterval's. It may be shared temporarily during coalescing though.
> 
> Let's call it a bug. In that case, clear() is fine, but a VNI is accidentally shared somewhere.
> 
>>  Either way, VNI are all bump allocated so the dtor should not be called?
> 
> Yeah, but they contain a SmallVector that leaks if it is not destroyed.

Adding more clear()s doesn't fix the leaks though, and sometimes I get
double-frees.
I don't really understand what happens with VNInfos after liveintervals
are joined.

So instead of using clear() I tought BumpPtrAllocator to iterate over
all the allocated slabs, and call a destructor function.
In our case all the objects we allocate are of same size, so by simply
iterating on the slabs with that size (and alignment) we find the
pointers to all the VNInfos we allocated, and call their destructor.

The valnos list doesn't seem to be reliable for that purpose.

I'm testing the attached patch now.

Best regards,
--Edwin
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