[PATCH] D107097: [llvm-profgen] An option to ignore parsing MMap events

[Lei Wang via Phabricator via llvm-commits]

wlei added a comment.

In D107097#2914552 <https://reviews.llvm.org/D107097#2914552>, @hoy wrote:

> In D107097#2914528 <https://reviews.llvm.org/D107097#2914528>, @wlei wrote:
>
>> In D107097#2914487 <https://reviews.llvm.org/D107097#2914487>, @hoy wrote:
>>
>>> Can the mmap events be treated as optional, so when they present we parse them otherwise just move forward to other events?
>>
>> That might have issues with the leading samples before we meet a MMAP, they won't know which binary it belongs to. Currently If not specify `ignore-mmap-events`, we will always check the `Addr2Binary` table which is empty without mmap events parsed.
>
> Can this be fixed? Without mmap events we can just use the preferred address as the load address.
>
> It sounds a bit unclear to me by giving `ignore-mmap-events` when the map events are there. That means we basically do not trust those events.

Understood! My concern is if the scripts has mmap events and only the leading sample missed the load address, they still can be loaded at a different base address which is not the preferred address. it's wrong base address in that case,

How about change it to `always-trust-mmap-events`, with this, the leading no-matched samples will be dropped. otherwise, it will use preferred address as load address.


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https://reviews.llvm.org/D107097