[LLVMdev] ManagedStatic and order of destruction

[Justin Holewinski]

Right, I'm suggesting we keep llvm_shutdown() for users who want this
control, but also destroy still-live ManagedStatic instances if
llvm_shutdown() is not called.  This helps in the case where there is not a
clear time when llvm_shutdown() can be called, especially given that LLVM
cannot be resurrected in the same process due to current limitations in the
pass registry, and perhaps elsewhere.


On Wed, Feb 13, 2013 at 7:47 AM, Nicholas Chapman
<admin at indigorenderer.com>wrote:

>  Hi Justin,
> I don't know anything about the details of llvm_shutdown and the
> ManagedStatic implementation.
> But it's nice to be able to explicitly free memory allocated by LLVM,
> otherwise such memory (allocated by global objects) can show up as memory
> leaks.
>
> Thanks,
>     Nick C.
>
>  On 12/02/2013 6:31 p.m., Justin Holewinski wrote:
>
> Ping.  Anyone with knowledge of detailed knowledge of the ManagedStatic
> implementation?
>
>  The use-case we are looking at is getting rid of llvm_shutdown() by
> cleaning up the ManagedStatic data when the global destructors run.
>
>
> On Sat, Feb 9, 2013 at 5:25 PM, Justin Holewinski <
> justin.holewinski at gmail.com> wrote:
>
>> I'm curious about the design rationale for how ManagedStatic instances
>> are cleaned up, and I'm hoping someone can shed some light on it.
>>
>>  Currently, ManagedStatic objects are cleaned up when llvm_shutdown()
>> traverses the global list of initialized objects and calls destroy() on
>> each.  This leads to two questions:
>>
>>  1. An assertion enforces that the objects are deleted in reverse order
>> of allocation.  Is there any hard requirement for this, or is it only
>> because of the way the linked list is created?
>>
>>  2. Would anything change (functionally) if we simply called destroy()
>> in the ManagedStatic destructor?  Wouldn't this be safer than relying on a
>> client to call llvm_shutdown()?  It seems like the whole purpose of
>> llvm_shutdown() is to allow clients to free the data allocated by
>> ManagedStatic instances.  Could we not just give them an option, but by
>> default clean up during global destruction?
>>
>>  --
>>
>> Thanks,
>>
>>  Justin Holewinski
>>
>
>
>
>  --
>
> Thanks,
>
>  Justin Holewinski
>
>
> _______________________________________________
> LLVM Developers mailing listLLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.eduhttp://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>


-- 

Thanks,

Justin Holewinski
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130213/f3e362c3/attachment.html>