Re: [PATCH] perf/x86/intel: Mark expected switch fall-throughs

Arnaldo Carvalho de Melo
2019-06-25T23:46:40Z

Em Tue, Jun 25, 2019 at 01:27:46PM -0700, Nathan Chancellor escreveu:
> On Tue, Jun 25, 2019 at 09:53:09PM +0200, Thomas Gleixner wrote:
> > On Tue, 25 Jun 2019, Nathan Chancellor wrote:
> > > On Tue, Jun 25, 2019 at 10:12:42AM -0700, Kees Cook wrote:
> > > > On Tue, Jun 25, 2019 at 09:18:46AM +0200, Peter Zijlstra wrote:
> > > > > Can it build a kernel without patches yet? That is, why should I care
> > > > > what LLVM does?
> > > >
> > > > Yes. LLVM trunk builds and boots x86 now. As for distro availability,
> > > > AIUI, the asm-goto feature missed the 9.0 LLVM branch point, so it'll
> > > > appear in the following release.
> > > >
> > > > --
> > > > Kees Cook
> > >
> > > I don't think that's right. LLVM 9 hasn't been branched yet so it should
> > > make it in.
> > >
> > > http://lists.llvm.org/pipermail/llvm-dev/2019-June/133155.html
> > >
> > > If anyone wants to play around with it before then, we wrote a
> > > self-contained script that will build an LLVM toolchain suitable for
> > > kernel development:
> > >
> > > https://github.com/ClangBuiltLinux/tc-build
> >
> > Useful!
> >
> > But can the script please check for a minimal clang version required to
> > build that thing.
> >
> > The default clang-3.8 which is installed on Debian stretch explodes. The
> > 6.0 variant from backports works as advertised.
> >
>
> Hmmm interesting, I test a lot of different distros using Docker
> containers to make sure the script works universally and that includes
> Debian stretch, which is the stress tester because all of the packages
> are older.

Interesting, I've been building tools/perf, tools/{lib,arch/include},
etc with lots of clang versions for quite a while, all in containers,
using podman:

----------------------------
The first ones are container based builds of tools/perf with and without libelf
support. Where clang is available, it is also used to build perf with/without
libelf, and building with LIBCLANGLLVM=1 (built-in clang) with gcc and clang
when clang and its devel libraries are installed.

Several are cross builds, the ones with -x-ARCH and the android one, and those
may not have all the features built, due to lack of multi-arch devel packages,
available and being used so far on just a few, like
debian:experimental-x-{arm64,mipsel}.

$ export PERF_TARBALL=http://192.168.124.1/perf/perf-5.2.0-rc4.tar.xz
$ dm
1 alpine:3.4 : Ok gcc (Alpine 5.3.0) 5.3.0, clang version 3.8.0 (tags/RELEASE_380/final)
2 alpine:3.5 : Ok gcc (Alpine 6.2.1) 6.2.1 20160822, clang version 3.8.1 (tags/RELEASE_381/final)
3 alpine:3.6 : Ok gcc (Alpine 6.3.0) 6.3.0, clang version 4.0.0 (tags/RELEASE_400/final)
4 alpine:3.7 : Ok gcc (Alpine 6.4.0) 6.4.0, Alpine clang version 5.0.0 (tags/RELEASE_500/final) (based on LLVM 5.0.0)
5 alpine:3.8 : Ok gcc (Alpine 6.4.0) 6.4.0, Alpine clang version 5.0.1 (tags/RELEASE_501/final) (based on LLVM 5.0.1)
6 alpine:3.9 : Ok gcc (Alpine 8.3.0) 8.3.0, Alpine clang version 5.0.1 (tags/RELEASE_502/final) (based on LLVM 5.0.1)
7 alpine:edge : Ok gcc (Alpine 8.3.0) 8.3.0, Alpine clang version 7.0.1 (tags/RELEASE_701/final) (based on LLVM 7.0.1)
8 amazonlinux:1 : Ok gcc (GCC) 7.2.1 20170915 (Red Hat 7.2.1-2), clang version 3.6.2 (tags/RELEASE_362/final)
9 amazonlinux:2 : Ok gcc (GCC) 7.3.1 20180303 (Red Hat 7.3.1-5), clang version 7.0.1 (Amazon Linux 2 7.0.1-1.amzn2.0.2)
10 android-ndk:r12b-arm : Ok arm-linux-androideabi-gcc (GCC) 4.9.x 20150123 (prerelease)
11 android-ndk:r15c-arm : Ok arm-linux-androideabi-gcc (GCC) 4.9.x 20150123 (prerelease)
12 centos:5 : Ok gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-55)
13 centos:6 : Ok gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23)
14 centos:7 : Ok gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-36)
15 clearlinux:latest : Ok gcc (Clear Linux OS for Intel Architecture) 9.1.1 20190611 gcc-9-branch@272162
16 debian:8 : Ok gcc (Debian 4.9.2-10+deb8u2) 4.9.2, Debian clang version 3.5.0-10 (tags/RELEASE_350/final) (based on LLVM 3.5.0)
17 debian:9 : Ok gcc (Debian 6.3.0-18+deb9u1) 6.3.0 20170516, clang version 3.8.1-24 (tags/RELEASE_381/final)
18 debian:experimental : Ok gcc (Debian 8.3.0-7) 8.3.0, clang version 7.0.1-8 (tags/RELEASE_701/final)
19 debian:experimental-x-arm64 : Ok aarch64-linux-gnu-gcc (Debian 8.3.0-7) 8.3.0
20 debian:experimental-x-mips : Ok mips-linux-gnu-gcc (Debian 8.3.0-7) 8.3.0
21 debian:experimental-x-mips64 : Ok mips64-linux-gnuabi64-gcc (Debian 8.3.0-7) 8.3.0
22 debian:experimental-x-mipsel : Ok mipsel-linux-gnu-gcc (Debian 8.3.0-7) 8.3.0
23 fedora:20 : Ok gcc (GCC) 4.8.3 20140911 (Red Hat 4.8.3-7), clang version 3.4.2 (tags/RELEASE_34/dot2-final)
24 fedora:22 : Ok gcc (GCC) 5.3.1 20160406 (Red Hat 5.3.1-6)
25 fedora:23 : Ok gcc (GCC) 5.3.1 20160406 (Red Hat 5.3.1-6), clang version 3.7.0 (tags/RELEASE_370/final)
26 fedora:24 : Ok gcc (GCC) 6.3.1 20161221 (Red Hat 6.3.1-1), clang version 3.8.1 (tags/RELEASE_381/final)
27 fedora:24-x-ARC-uClibc : Ok arc-linux-gcc (ARCompact ISA Linux uClibc toolchain 2017.09-rc2) 7.1.1 20170710
28 fedora:25 : Ok gcc (GCC) 6.4.1 20170727 (Red Hat 6.4.1-1), clang version 3.9.1 (tags/RELEASE_391/final)
29 fedora:26 : Ok gcc (GCC) 7.3.1 20180130 (Red Hat 7.3.1-2), clang version 4.0.1 (tags/RELEASE_401/final)
30 fedora:27 : Ok gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-6), clang version 5.0.2 (tags/RELEASE_502/final)
31 fedora:28 : Ok gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2), clang version 6.0.1 (tags/RELEASE_601/final)
32 fedora:29 : Ok gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2), clang version 7.0.1 (Fedora 7.0.1-6.fc29)
33 fedora:30 : Ok gcc (GCC) 9.1.1 20190503 (Red Hat 9.1.1-1), clang version 8.0.0 (Fedora 8.0.0-1.fc30)
34 fedora:30-x-ARC-glibc : Ok arc-linux-gcc (ARC HS GNU/Linux glibc toolchain 2019.03-rc1) 8.3.1 20190225
35 fedora:30-x-ARC-uClibc : Ok arc-linux-gcc (ARCv2 ISA Linux uClibc toolchain 2019.03-rc1) 8.3.1 20190225
36 fedora:31 : Ok gcc (GCC) 9.1.1 20190605 (Red Hat 9.1.1-2), clang version 8.0.0 (Fedora 8.0.0-3.fc31)
37 fedora:rawhide : Ok gcc (GCC) 9.1.1 20190605 (Red Hat 9.1.1-2), clang version 8.0.0 (Fedora 8.0.0-3.fc31)
38 gentoo-stage3-amd64:latest : Ok gcc (Gentoo 8.3.0-r1 p1.1) 8.3.0
39 mageia:5 : Ok gcc (GCC) 4.9.2, clang version 3.5.2 (tags/RELEASE_352/final)
40 mageia:6 : Ok gcc (Mageia 5.5.0-1.mga6) 5.5.0, clang version 3.9.1 (tags/RELEASE_391/final)
41 mageia:7 : Ok gcc (Mageia 8.3.1-0.20190524.1.mga7) 8.3.1 20190524, clang version 8.0.0 (Mageia 8.0.0-1.mga7)
42 manjaro:latest : Ok gcc (GCC) 8.3.0, clang version 8.0.0 (tags/RELEASE_800/final)
1 openmandriva:cooker : Ok gcc (GCC) 9.1.0 20190503 (OpenMandriva)
43 opensuse:15.0 : Ok gcc (SUSE Linux) 7.4.1 20190424 [gcc-7-branch revision 270538], clang version 5.0.1 (tags/RELEASE_501/final 312548)
44 opensuse:15.1 : Ok gcc (SUSE Linux) 7.4.0, clang version 7.0.1 (tags/RELEASE_701/final 349238)
45 opensuse:42.3 : Ok gcc (SUSE Linux) 4.8.5, clang version 3.8.0 (tags/RELEASE_380/final 262553)
46 opensuse:tumbleweed : Ok gcc (SUSE Linux) 9.1.1 20190520 [gcc-9-branch revision 271396], clang version 7.0.1 (tags/RELEASE_701/final 349238)
47 oraclelinux:6 : Ok gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23.0.1)
48 oraclelinux:7 : Ok gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-36.0.1), clang version 3.4.2 (tags/RELEASE_34/dot2-final)
49 ubuntu:12.04 : Ok gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
50 ubuntu:14.04 : Ok gcc (Ubuntu 4.8.4-2ubuntu1~14.04.4) 4.8.4, Ubuntu clang version 3.4-1ubuntu3 (tags/RELEASE_34/final) (based on LLVM 3.4)
51 ubuntu:16.04 : Ok gcc (Ubuntu 5.4.0-6ubuntu1~16.04.11) 5.4.0 20160609, clang version 3.8.0-2ubuntu4 (tags/RELEASE_380/final)
52 ubuntu:16.04-x-arm : Ok arm-linux-gnueabihf-gcc (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
53 ubuntu:16.04-x-arm64 : Ok aarch64-linux-gnu-gcc (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
54 ubuntu:16.04-x-powerpc : Ok powerpc-linux-gnu-gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
55 ubuntu:16.04-x-powerpc64 : Ok powerpc64-linux-gnu-gcc (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
56 ubuntu:16.04-x-powerpc64el : Ok powerpc64le-linux-gnu-gcc (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
57 ubuntu:16.04-x-s390 : Ok s390x-linux-gnu-gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
58 ubuntu:18.04 : Ok gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0, clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
59 ubuntu:18.04-x-arm : Ok arm-linux-gnueabihf-gcc (Ubuntu/Linaro 7.4.0-1ubuntu1~18.04) 7.4.0
60 ubuntu:18.04-x-arm64 : Ok aarch64-linux-gnu-gcc (Ubuntu/Linaro 7.4.0-1ubuntu1~18.04) 7.4.0
61 ubuntu:18.04-x-m68k : Ok m68k-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
62 ubuntu:18.04-x-powerpc : Ok powerpc-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
63 ubuntu:18.04-x-powerpc64 : Ok powerpc64-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
64 ubuntu:18.04-x-powerpc64el : Ok powerpc64le-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
65 ubuntu:18.04-x-riscv64 : Ok riscv64-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
66 ubuntu:18.04-x-s390 : Ok s390x-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
67 ubuntu:18.04-x-sh4 : Ok sh4-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
68 ubuntu:18.04-x-sparc64 : Ok sparc64-linux-gnu-gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0
69 ubuntu:18.10 : Ok gcc (Ubuntu 8.3.0-6ubuntu1~18.10.1) 8.3.0, clang version 7.0.0-3 (tags/RELEASE_700/final)
70 ubuntu:19.04 : Ok gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0, clang version 8.0.0-3 (tags/RELEASE_800/final)
71 ubuntu:19.04-x-alpha : Ok alpha-linux-gnu-gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0
72 ubuntu:19.04-x-arm64 : Ok aarch64-linux-gnu-gcc (Ubuntu/Linaro 8.3.0-6ubuntu1) 8.3.0
73 ubuntu:19.04-x-hppa : Ok hppa-linux-gnu-gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0
$

- Arnaldo