[LLVMdev] [RFC] Less memory and greater maintainability for debug info IR

Eric Christopher echristo at gmail.com
Tue Oct 14 13:18:06 PDT 2014


On Tue, Oct 14, 2014 at 1:17 PM, Rafael EspĂ­ndola
<rafael.espindola at gmail.com> wrote:
>>> Stupid question, but when I was working on LTO last Summer the primary
>>> culprit for excessive memory use was due to us not being smart when linking
>>> the IR together (Espindola would know more details). Do we still have that
>>> problem? For starters, how does the memory usage of just llvm-link compare
>>> to the memory usage of the actual LTO run? If the issue I was seeing last
>>> Summer is still there, you should see that the invocation of llvm-link is
>>> actually the most memory-intensive part of the LTO step, by far.
>>>
>>
>> This is vague. Could you be more specific on where you saw all of the memory?
>
> I think Sean is referring to the old problem of nodes not being merged
> because of cycles. It has been fixed by breaking the cycles by having
> some of the edges be represented with stable mangled names.
>

That's what I was thinking and why I was asking :)

> The problem that Duncan is trying to solve is that the debug info is
> still very large, even with the duplicate information removed.

Very much so. Duncan and I (and others) have been chatting about this for a bit.

-eric




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