GitHub pull request #3391 of commit e63b436d936c2dba01af2c7750ec3273b7ac5e7a, no merge conflicts.sha1origin/pr/3391/mergeghprbActualCommite63b436d936c2dba01af2c7750ec3273b7ac5e7aghprbActualCommitAuthorghprbActualCommitAuthorEmailghprbAuthorRepoGitUrlhttps://github.com/davemarchevsky/bcc.gitghprbTriggerAuthorghprbTriggerAuthorEmailghprbTriggerAuthorLoginyonghong-songghprbTriggerAuthorLoginMention@yonghong-songghprbPullId3391ghprbTargetBranchmasterghprbSourceBranchfix_bswap_includesGIT_BRANCHfix_bswap_includesghprbPullAuthorEmaildavemarchevsky@gmail.comghprbPullAuthorLogindavemarchevskyghprbPullAuthorLoginMention@davemarchevskyghprbPullDescriptionGitHub pull request #3391 of commit e63b436d936c2dba01af2c7750ec3273b7ac5e7a, no merge conflicts.ghprbPullTitleMove HAVE_BUILTIN_BSWAP includes to separate headerghprbPullLinkhttps://github.com/iovisor/bcc/pull/3391ghprbPullLongDescriptionAs reported in #3366, on newer kernels bcc complains about macro\r\nredefinition when compiling bpf programs:\r\n\r\n```\r\ninclude/linux/compiler-clang.h:46:9: warning: '__HAVE_BUILTIN_BSWAP64__' macro redefined [-Wmacro-redefined]\r\n\#define __HAVE_BUILTIN_BSWAP64__\r\n ^\r\n<command line>:5:9: note: previous definition is here\r\n\#define __HAVE_BUILTIN_BSWAP64__ 1\r\n```\r\n\r\nSince these macros are passed in as `-D` cflags, they appear first\r\nbefore any \#define statements in code. Since an [upstream kernel\r\npatch](https://lore.kernel.org/linux-csky/20210226161151.2629097-1-arnd@kernel.org/)\r\nadded these defines in a kernel header, we see the warning.\r\n\r\nThis patch moves these definitions to a separate 'virtual' header that's included\r\nafter virtual_bpf.h and adds an ifndef guard. As a result, newer kernels\r\nwith the patch will not trigger the warning, while older kernels will\r\nnot lose the definition.\r\n\r\nThis should be safe based on my digging - some existing bcc programs use\r\n`__builtin_bswap` methods, but without checking HAVE_BUILTIN_BSWAP.\r\nMacros that may be conditionally defined based on HAVE_BUILTIN_BSWAP,\r\nlike those in `bpf_endian.h`, aren't. If a similar macro or struct def\r\nin virtual_bpf.h - or any header it pulls in - changes depending on\r\nHAVE_BUILTIN_BSWAP this could cause problems on older kernels, but I\r\ndon't believe that this is the case, or will be based on how\r\ninfrequently the defines are checked.ghprbCommentBody[buildbot, test this please]ghprbGhRepositoryiovisor/bccghprbCredentialsId6d3daf13-69b8-48b1-9c8f-ec5353264113false<a title="Move HAVE_BUILTIN_BSWAP includes to separate header" href="https://github.com/iovisor/bcc/pull/3391">PR #3391</a>: Move HAVE_BUILTIN_BSWAP inc...#95312369927460664bcc-pr #953953false9537633SUCCESS1619823952212https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/953/git953https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc25/953/953https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc26/953/953https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc27/953/953https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc28/953/953https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=ubuntu1604/953/953https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=ubuntu1710/953/953https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=ubuntu1804/953/