Re: [PATCH 2/2] recordmcount: Handle sections with no non-weak symbols

From: Naveen N. Rao
Date: Thu Apr 28 2022 - 13:24:58 EST


Steven Rostedt wrote:
On Thu, 28 Apr 2022 13:15:22 +0530
"Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> wrote:

Indeed, plain old -pg will be a problem. I'm not sure there is a generic way to address this. I suppose architectures will have to validate the mcount locations, something like this?

Perhaps another solution is to make the mcount locations after the linking
is done. The main downside to that is that it takes time to go over the
entire vmlinux, and will slow down a compile that only modified a couple of
files.

Yes, and I think that is also very useful with LTO. So, that would be a good one to consider in the longer term.

For now, I have posted a v2 of this series with your comments addressed. It is working well in my tests on powerpc in the different configurations, including the older elf abi v1 that uses -pg. If it looks ok to you, we can use this approach for now.


Thanks,
Naveen