Can't compile openzfs with "-Og" - inline failed within the ZSTD module

[ocehugo]

System information

Distribution Name | Gentoo
Distribution Version | None
Kernel Version | 5.1.14-6.1.22
Architecture | x86_64
OpenZFS Version | 2.1.9-2.1.10

Describe the problem you're observing

I can't compile ZFS with gcc-12 and "-Og". There is an error about inlining within the ZSTD module:

module/zstd/lib/zstd.c:18954:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_selectMLS': function not considered for inlining

Changing back to "-O2" does solve the problem. A corner case I believe, but since I use "-Og" globally for simplicity and zfs is usually only updated when I also upgrade the kernel, this was a hurdle at the wrong time :)

PS: I can't tell you when this surfaced, but certainly after 2.1.4.

Describe how to reproduce the problem

Just compile zfs with CFLAGS="-Og"

[admnd]

Could you please put the full command-line here or better: what emerge --info reports ?
Unless you are tracking down a ZFS issue / debugging it there is not point to use -Og, but you might have hit a compiler issue.

PS: If not done already, could you also, please, open a Gentoo bug here => https://bugs.gentoo.org (and link your Gentoo bug with this one).

[thesamesam]

This is probably related to:

• GCC-12 fails to inline XXX_FORCED_INLINE functions, XXH3_accumulate_512_sse2(), and XXH3_scrambleAcc_sse2() with -Og flag. Cyan4973/xxHash#800
• https://bugs.gentoo.org/895080 - Build failure with gcc-12 Perl/perl5#19776
• https://bugs.gentoo.org/896444
• https://bugs.gentoo.org/902075
• https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107931

Really, forced-inlining is extremely brittle.

[stale]

This issue has been automatically marked as "stale" because it has not had any activity for a while. It will be closed in 90 days if no further activity occurs. Thank you for your contributions.

[intelfx]

Not stale, still happens building current master (b6bd322) with GCC 15.2.1 and these flags (which is essentially Arch flags but s/-O2/-Og -ggdb3/ + -Wno-error to avoid tripping over -Wmaybe-uninitialized):

$ export CFLAGS='-march=native -pipe -fno-plt -fexceptions -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security -fstack-clash-protection -fcf-protection -fuse-ld=mold -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -Og -ggdb3 -Wno-error'

$ export LDFLAGS='-Wl,-O1 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro -Wl,-z,now -Wl,-z,pack-relative-relocs -fuse-ld=mold'

$ ./autogen.sh && ./configure --prefix=/usr --with-config=all --enable-linux-experimental --enable-debug && make -j$(nproc)
In function 'ZSTD_compressBlock_lazy_generic',
    inlined from 'zfs_ZSTD_compressBlock_lazy2' at module/zstd/lib/compress/zstd_lazy.c:883:12:
module/zstd/lib/compress/zstd_lazy.c:572:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_selectMLS': function not considered for inlining
  572 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:718:32: note: called from here
  718 |             size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:572:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_selectMLS': function not considered for inlining
  572 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:756:36: note: called from here
  756 |                 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:572:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_selectMLS': function not considered for inlining
  572 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:791:40: note: called from here
  791 |                     size_t const ml2 = searchMax(ms, ip, iend, &offset2);
      |                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'ZSTD_compressBlock_lazy_generic',
    inlined from 'zfs_ZSTD_compressBlock_lazy' at module/zstd/lib/compress/zstd_lazy.c:890:12:
module/zstd/lib/compress/zstd_lazy.c:572:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_selectMLS': function not considered for inlining
  572 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:718:32: note: called from here
  718 |             size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:572:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_selectMLS': function not considered for inlining
  572 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:756:36: note: called from here
  756 |                 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'ZSTD_compressBlock_lazy_generic',
    inlined from 'zfs_ZSTD_compressBlock_greedy' at module/zstd/lib/compress/zstd_lazy.c:897:12:
module/zstd/lib/compress/zstd_lazy.c:572:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_selectMLS': function not considered for inlining
  572 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:718:32: note: called from here
  718 |             size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'ZSTD_compressBlock_lazy_extDict_generic',
    inlined from 'zfs_ZSTD_compressBlock_greedy_extDict' at module/zstd/lib/compress/zstd_lazy.c:1118:12:
module/zstd/lib/compress/zstd_lazy.c:604:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_extDict_selectMLS': function not considered for inlining
  604 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:990:32: note: called from here
  990 |             size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'ZSTD_compressBlock_lazy_extDict_generic',
    inlined from 'zfs_ZSTD_compressBlock_lazy_extDict' at module/zstd/lib/compress/zstd_lazy.c:1126:12:
module/zstd/lib/compress/zstd_lazy.c:604:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_extDict_selectMLS': function not considered for inlining
  604 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:990:32: note: called from here
  990 |             size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:604:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_extDict_selectMLS': function not considered for inlining
  604 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:1025:36: note: called from here
 1025 |                 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'ZSTD_compressBlock_lazy_extDict_generic',
    inlined from 'zfs_ZSTD_compressBlock_lazy2_extDict' at module/zstd/lib/compress/zstd_lazy.c:1134:12:
module/zstd/lib/compress/zstd_lazy.c:604:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_extDict_selectMLS': function not considered for inlining
  604 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:990:32: note: called from here
  990 |             size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:604:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_extDict_selectMLS': function not considered for inlining
  604 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:1025:36: note: called from here
 1025 |                 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:604:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_extDict_selectMLS': function not considered for inlining
  604 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module/zstd/lib/compress/zstd_lazy.c:1057:40: note: called from here
 1057 |                     size_t const ml2 = searchMax(ms, ip, iend, &offset2);
      |                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
make[2]: *** [Makefile:11149: module/zstd/lib/compress/libzstd_la-zstd_lazy.lo] Error 1
make[2]: Leaving directory '/home/intelfx/devel/ext/zfs'
make[1]: *** [Makefile:12625: all-recursive] Error 1
make[1]: Leaving directory '/home/intelfx/devel/ext/zfs'
make: *** [Makefile:4820: all] Error 2

[alex-moch]

Could someone please check a build with -Og -g -DZSTD_NO_INLINE before and after my pull request #18089?

Before the pull request, the build fails with:

  CC       module/zstd/lib/compress/libzstd_la-zstd_lazy.lo
In function 'ZSTD_compressBlock_lazy_generic',                                                                        
    inlined from 'zfs_ZSTD_compressBlock_lazy2' at module/zstd/lib/compress/zstd_lazy.c:883:12:
module/zstd/lib/compress/zstd_lazy.c:572:30: error: inlining failed in call to 'always_inline' 'ZSTD_HcFindBestMatch_s
electMLS': function not considered for inlining                                                                       
  572 | FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (       
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[...]

After the pull request, the build succeeds (with a few warnings).