[llvm-dev] Switching to the New Pass Manager by Default
Eric Christopher via llvm-dev
llvm-dev at lists.llvm.org
Fri Aug 2 17:20:45 PDT 2019
Getting ubsan ported would be good if it hasn't. Do you happen to know
what's needed there?
On Fri, Aug 2, 2019 at 2:29 PM Leonard Chan via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> I believe a good amount of them (if not most of them) have already been ported! Off the top of my head, I remember that asan, tsan, msan, hwasan, the kernel santizers, and sancov have been ported. I don't think ubsan has been ported yet though.
> You can also check if other passes you need run under the new PM by checking PassRegistry.def.
> On Fri, Aug 2, 2019, 14:20 Jordan Rupprecht <rupprecht at google.com> wrote:
>> Hi Leonard,
>> Is the new pass manager expected to work with sanitizers now?
>> On Fri, Aug 2, 2019 at 1:25 PM Leonard Chan via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>>> I think so far most individual projects have their own statistics on build time/performance impact on switching to the new PM, but I agree that there should at least be one place that people can reference on the impact.
>>> On Fri, Aug 2, 2019 at 1:14 PM Philip Reames <listmail at philipreames.com> wrote:
>>>> Thanks for all the hard work that went into getting it here.
>>>> Can you spell out what performance validation has been done? Informally, I know there's been quite a bit, but getting a summary in one place for later reference would be super helpful.
>>>> On 8/2/19 10:25 AM, Leonard Chan via llvm-dev wrote:
>>>> Hello all,
>>>> As of now, all LLVM and Clang tests have been updated/addressed to run under the new/experimental pass manager (at least the ones that failed when using the new PM).
>>>> For those who aren't aware of what the new pass manager (PM) is, the tl;dr is that this will serve as a replacement for the legacy PM, and promises faster build times by restructuring how passes are run over IR units. For some time, when someone wants to create a new pass, they may need to implement it for both pass managers since the legacy one is what is enabled by default. Passes that were initially made under the new PM have also slowly been ported over time.
>>>> Now that LLVM 9.0.0 has branched, we have about 6 months before the next release. We think it would be a good idea to take this opportunity and make the new PM the default one which gives us enough time to work out any kinks that might come out of this switch before LLVM 10.0.0 branch point. We suspect that there may be other LLVM projects that will be affected by this, probably from unported passes.
>>>> Does anyone have any opinions on this?
>>>> Off the top of my head, the next immediate work would be to update the docs with instructions on how to write or port a new PM pass, and address any breakages for other LLVM projects.
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
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