[cfe-dev] [CrossTU] [CTU] Status of Cross Translation Unit Static Analysis, and a new build server

David Blaikie via cfe-dev cfe-dev at lists.llvm.org
Wed Nov 20 11:10:12 PST 2019

On Wed, Nov 20, 2019 at 2:47 AM Gábor Márton <martongabesz at gmail.com> wrote:

> > Any chance this could be wired up to the existing buildbot or jenkins
> infrastructure, rather than having another one?
> Parallel to the Jenkins job we started to work on a simplified buildbot
> instance, see https://reviews.llvm.org/D61848. The process of integrating
> that, however, seems to be stuck. Maybe Galina and Endre could revive that
> process? Also, the Jenkins job is long running job, it takes 8 hours to
> complete (8cores/64GB azure vm), but it analyzes 6 C/C++ projects. The
> buildbot is quick, it takes roughly 1-2 hours, but analyzes only one simple
> C project.
> About Jenkins in LLVM I have many infrastructural questions:
> Is there a way to integrate our Jenkins job to any LLVM Jenkins cluster? I
> know about http://green.lab.llvm.org/green/,  but that cluster seems to
> be OSX only. We need Linux. Is there a Jenkins cluster of Linux executors
> we could use? Should we somehow connect our Azure vm into that cluster as
> an additional executor?

Hey Adrian - is there any likelihood/interest in having Green Dragon
include non-apple-managed builders/scenarios in part to avoid proliferation
of distinct CI systems?

> Gabor
> On Tue, Nov 19, 2019 at 8:48 PM David Blaikie <dblaikie at gmail.com> wrote:
>> Any chance this could be wired up to the existing buildbot or jenkins
>> infrastructure, rather than having another one?
>> (I'm not 100% sure it's better for it to all be together, but figured I'd
>> ask/perhaps there are reasons that've already been considered/articulated)
>> On Mon, Nov 18, 2019 at 9:18 AM Gábor Márton via cfe-dev <
>> cfe-dev at lists.llvm.org> wrote:
>>> Dear Clang Community,
>>> TLDR; I'd like to encourage you to experiment with CTU static analysis
>>> because it has evolved a lot this year! Usage documentation
>>> <https://clang.llvm.org/docs/analyzer/user-docs/CrossTranslationUnit.html>
>>> is available online.
>>> This year, we have landed several ASTImporter patches that made it
>>> possible to analyze even C++11/14 projects with reasonable stability. I
>>> can confidently assure you that the upstream master of llvm/llvm-project
>>> is as stable as our downstream fork. We've made enormous efforts to
>>> properly implement the error handling of ASTImporter and this way we could
>>> dramatically improve the stability of CTU. We do have a few more patches
>>> <https://github.com/Ericsson/clang/projects/2> that we still want to
>>> land in the future, but they are not error handling related. From Clang
>>> version 10, we no longer plan to maintain our CTU downstream fork.
>>> We have set up a publicly available Jenkins build server
>>> <http://codechecker-buildbot.eastus.cloudapp.azure.com:8080/job/ctu_pipeline_clang-master-monorepo/>
>>> that continuously analyzes the following C and C++ projects:
>>> - Tmux (C)
>>> - Curl (C)
>>> - Redis (C)
>>> - Xerces (C++14)
>>> - Bitcoin (C++11)
>>> - Protobuf (C++11/C++14)
>>> CTU analysis results are compared to non-CTU results
>>> <http://codechecker-buildbot.eastus.cloudapp.azure.com:8080/job/ctu_pipeline_clang-master-monorepo/CTU_20results_20on_20open_20projects_20_28C_29/>,
>>> both for C projects and C++ projects. CTU always results in more
>>> findings, and the false-positive/true-positive ratio remains roughly
>>> the same [1]. We are monitoring the analysis job, and if an
>>> assertion/crash happens then we are going to get in touch with the
>>> author of the commit that plausibly caused the error. We also have a buildbot
>>> patch <https://reviews.llvm.org/D61848> in Phabricator which is ought
>>> to analyse only one simple C project (Tmux). We decided to install
>>> Jenkins because of ownership and flexibility. The buildbot code is
>>> pretty convoluted and review and communication are very slow. The buildbot
>>> also uses CodeChecker as a dependency, changes to its workflow requires
>>> changes in the buildbot configuration as well.
>>> Notes:
>>> Please note that our primary target for CTU is Linux, and we encourage everybody
>>> to use CodeChecker <https://github.com/Ericsson/codechecker> for CTU
>>> (scan-build is no longer supported *by CTU developers*). Projects that
>>> use templates heavily may expect an increase in analysis time. Also
>>> note that CTU can be very memory consuming, e.g. in case of the
>>> analysis run on LLVM code we've seen 10GB of resident memory usage for
>>> one process. Thus, it may be useful to set a maximum limit for the
>>> loaded ASTUnits (e.g. -analyzer-config ctu-import-threshold=8, with
>>> CodeChecker you need to edit an saargs file
>>> <https://github.com/Ericsson/codechecker/blob/master/docs/analyzer/checker_and_analyzer_configuration.md>
>>> ).
>>> [1] 2017 EuroLLVM Developers’ Meeting: G. Horvath “Cross Translational
>>> Unit Analysis in Clang ...”
>>> Cheers,
>>> Gabor Marton
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at lists.llvm.org
>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
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