# undefined reference to `pcre_jit_exec'

6 messages from 2017-10-12 to 2017-10-12. Participants: Jeffrey Walton, Jeff King, Ævar Arnfjörð Bjarmason.
Thread: https://gitlist.dev/t/46960

## Jeffrey Walton, 2017-10-12 20:06

Subject: undefined reference to `pcre_jit_exec'
Message-ID: <CAH8yC8mvG3bSpgshHay7B0SSyAafWLrPTtVZRuq2cShn9xQ9JA@mail.gmail.com>
URL: https://gitlist.dev/e/CAH8yC8mvG3bSpgshHay7B0SSyAafWLrPTtVZRuq2cShn9xQ9JA%40mail.gmail.com

```
Hi Everyone,

I have a script to build Git on some old platforms to ease testing.
Old platforms include CentOS 5. The script is available at
https://github.com/noloader/Build-Scripts/blob/master/build-ssh.sh.

It looks like something got knocked loose recently. I'm seeing several
of these when building with PCRE 8.41 with Git 2.14.2. Old and new
platforms are witnessing it. I observe it on CentOS 5 with GCC 4.1;
and Fedora 26 with GCC 7.2.

    ...
    LINK git-credential-store
libgit.a(grep.o): In function `pcre1match':
grep.c:(.text+0x1219): undefined reference to `pcre_jit_exec'
collect2: error: ld returned 1 exit status
make: *** [Makefile:2145: git-credential-store] Error 1

Jeff

****************************************

./configure ...

config.status: executing config.mak.autogen commands
    * new build flags
    * new prefix flags
    * new link flags
    GEN common-cmds.h
    CC hex.o
    CC ident.o
    CC kwset.o
    CC levenshtein.o
    CC line-log.o
    CC line-range.o
    CC list-objects.o
    CC ll-merge.o
    CC lockfile.o
    CC log-tree.o
    CC mailinfo.o
    CC mailmap.o
    CC match-trees.o
    CC merge.o
    CC merge-blobs.o
    CC merge-recursive.o
    CC mergesort.o
    CC mru.o
    CC name-hash.o
    CC notes.o
    CC notes-cache.o
    CC notes-merge.o
    CC notes-utils.o
    CC object.o
    CC oidset.o
    CC pack-bitmap.o
    CC pack-bitmap-write.o
    CC pack-check.o
    CC pack-objects.o
    CC pack-revindex.o
    CC pack-write.o
    CC pager.o
    CC parse-options.o
    CC parse-options-cb.o
    CC patch-delta.o
    CC patch-ids.o
    CC path.o
    CC pathspec.o
    CC pkt-line.o
    CC preload-index.o
    CC pretty.o
    CC prio-queue.o
    CC progress.o
    CC prompt.o
    CC quote.o
    CC reachable.o
    CC read-cache.o
    CC reflog-walk.o
    CC refs.o
    CC refs/files-backend.o
    CC refs/iterator.o
    CC refs/ref-cache.o
    CC ref-filter.o
    CC remote.o
    CC replace_object.o
    CC repository.o
    CC rerere.o
    CC resolve-undo.o
    CC revision.o
    CC run-command.o
    CC send-pack.o
    CC sequencer.o
    CC server-info.o
    CC setup.o
    CC sha1-array.o
    CC sha1-lookup.o
    CC sha1_file.o
    CC sha1_name.o
    CC shallow.o
    CC sideband.o
    CC sigchain.o
    CC split-index.o
    CC strbuf.o
    CC streaming.o
    CC string-list.o
    CC submodule.o
    CC submodule-config.o
    CC sub-process.o
    CC symlinks.o
    CC tag.o
    CC tempfile.o
    CC tmp-objdir.o
    CC trace.o
    CC trailer.o
    CC transport.o
    CC transport-helper.o
    CC tree-diff.o
    CC tree.o
    CC tree-walk.o
    CC unpack-trees.o
    CC url.o
    CC urlmatch.o
    CC usage.o
    CC userdiff.o
    CC utf8.o
    CC varint.o
    CC versioncmp.o
    CC walker.o
    CC wildmatch.o
    CC worktree.o
    CC wrapper.o
    CC write_or_die.o
    CC ws.o
    CC wt-status.o
    CC xdiff-interface.o
    CC zlib.o
    CC unix-socket.o
    CC sha1dc/sha1.o
    CC sha1dc/ubc_check.o
    CC thread-utils.o
    CC compat/fopen.o
    CC compat/strlcpy.o
    CC compat/qsort_s.o
    CC xdiff/xdiffi.o
    CC xdiff/xprepare.o
    CC xdiff/xutils.o
    CC xdiff/xemit.o
    CC xdiff/xmerge.o
    CC xdiff/xpatience.o
    CC xdiff/xhistogram.o
    CC daemon.o
    CC fast-import.o
    CC http-backend.o
    CC imap-send.o
    CC http.o
    CC sh-i18n--envsubst.o
    CC shell.o
    CC show-index.o
    CC upload-pack.o
    CC remote-testsvn.o
    CC vcs-svn/line_buffer.o
    CC vcs-svn/sliding_window.o
    CC vcs-svn/fast_export.o
    CC vcs-svn/svndiff.o
    CC vcs-svn/svndump.o
    CC http-walker.o
    CC http-fetch.o
    CC credential-cache.o
    CC credential-cache--daemon.o
    CC remote-curl.o
    * new script parameters
    * new perl-specific parameters
    * new Python interpreter location
    GEN git-instaweb
    GEN git-mergetool--lib
    GEN git-parse-remote
    GEN git-rebase--am
    GEN git-rebase--interactive
    GEN git-rebase--merge
    GEN git-sh-setup
    GEN git-sh-i18n
    CC git.o
    CC builtin/add.o
    CC builtin/am.o
    CC builtin/annotate.o
    CC builtin/apply.o
    CC builtin/archive.o
    CC builtin/bisect--helper.o
    CC builtin/blame.o
    CC builtin/branch.o
    CC builtin/bundle.o
    CC builtin/cat-file.o
    CC builtin/check-attr.o
    CC builtin/check-ignore.o
    CC builtin/check-mailmap.o
    CC builtin/check-ref-format.o
    CC builtin/checkout-index.o
    CC builtin/checkout.o
    CC builtin/clean.o
    CC builtin/clone.o
    CC builtin/column.o
    CC builtin/commit-tree.o
    CC builtin/commit.o
    CC builtin/config.o
    CC builtin/count-objects.o
    CC builtin/credential.o
    CC builtin/describe.o
    CC builtin/diff-files.o
    CC builtin/diff-index.o
    CC builtin/diff-tree.o
    CC builtin/diff.o
    CC builtin/difftool.o
    CC builtin/fast-export.o
    CC builtin/fetch-pack.o
    CC builtin/fetch.o
    CC builtin/fmt-merge-msg.o
    CC builtin/for-each-ref.o
    CC builtin/fsck.o
    CC builtin/gc.o
    CC builtin/get-tar-commit-id.o
    CC builtin/grep.o
    CC builtin/hash-object.o
    CC builtin/help.o
    CC builtin/index-pack.o
    CC builtin/init-db.o
    CC builtin/interpret-trailers.o
    CC builtin/log.o
    CC builtin/ls-files.o
    CC builtin/ls-remote.o
    CC builtin/ls-tree.o
    CC builtin/mailinfo.o
    CC builtin/mailsplit.o
    CC builtin/merge.o
    CC builtin/merge-base.o
    CC builtin/merge-file.o
    CC builtin/merge-index.o
    CC builtin/merge-ours.o
    CC builtin/merge-recursive.o
    CC builtin/merge-tree.o
    CC builtin/mktag.o
    CC builtin/mktree.o
    CC builtin/mv.o
    CC builtin/name-rev.o
    CC builtin/notes.o
    CC builtin/pack-objects.o
    CC builtin/pack-redundant.o
    CC builtin/pack-refs.o
    CC builtin/patch-id.o
    CC builtin/prune-packed.o
    CC builtin/prune.o
    CC builtin/pull.o
    CC builtin/push.o
    CC builtin/read-tree.o
    CC builtin/rebase--helper.o
    CC builtin/receive-pack.o
    CC builtin/reflog.o
    CC builtin/remote.o
    CC builtin/remote-ext.o
    CC builtin/remote-fd.o
    CC builtin/repack.o
    CC builtin/replace.o
    CC builtin/rerere.o
    CC builtin/reset.o
    CC builtin/rev-list.o
    CC builtin/rev-parse.o
    CC builtin/revert.o
    CC builtin/rm.o
    CC builtin/send-pack.o
    CC builtin/shortlog.o
    CC builtin/show-branch.o
    CC builtin/show-ref.o
    CC builtin/stripspace.o
    CC builtin/submodule--helper.o
    CC builtin/symbolic-ref.o
    CC builtin/tag.o
    CC builtin/unpack-file.o
    CC builtin/unpack-objects.o
    CC builtin/update-index.o
    CC builtin/update-ref.o
    CC builtin/update-server-info.o
    CC builtin/upload-archive.o
    CC builtin/var.o
    CC builtin/verify-commit.o
    CC builtin/verify-pack.o
    CC builtin/verify-tag.o
    CC builtin/worktree.o
    CC builtin/write-tree.o
    CC credential-store.o
    CC common-main.o
    CC abspath.o
    CC advice.o
    CC alias.o
    CC alloc.o
    CC apply.o
    CC archive.o
    CC archive-tar.o
    CC archive-zip.o
    CC argv-array.o
    CC attr.o
    CC base85.o
    CC bisect.o
    CC blame.o
    CC blob.o
    CC branch.o
    CC bulk-checkin.o
    CC bundle.o
    CC cache-tree.o
    CC color.o
    CC column.o
    CC combine-diff.o
    CC commit.o
    CC compat/obstack.o
    CC compat/terminal.o
    CC config.o
    CC connect.o
    CC connected.o
    CC convert.o
    CC copy.o
    CC credential.o
    CC csum-file.o
    CC ctype.o
    CC date.o
    CC decorate.o
    CC diffcore-break.o
    CC diffcore-delta.o
    CC diffcore-order.o
    CC diffcore-pickaxe.o
    CC diffcore-rename.o
    CC diff-delta.o
    CC diff-lib.o
    CC diff-no-index.o
    CC diff.o
    CC dir.o
    CC dir-iterator.o
    CC editor.o
    CC entry.o
    CC environment.o
    CC ewah/bitmap.o
    CC ewah/ewah_bitmap.o
    CC ewah/ewah_io.o
    CC ewah/ewah_rlw.o
    CC exec_cmd.o
    CC fetch-pack.o
    CC fsck.o
    CC gettext.o
    CC gpg-interface.o
    CC graph.o
    CC grep.o
    CC hashmap.o
    CC help.o
    CC version.o
    AR xdiff/lib.a
    AR vcs-svn/lib.a
    GEN git-bisect
    GEN git-difftool--helper
    GEN git-filter-branch
    GEN git-merge-octopus
    GEN git-merge-one-file
    GEN git-merge-resolve
    GEN git-mergetool
    GEN git-quiltimport
    GEN git-rebase
    GEN git-request-pull
    GEN git-stash
    GEN git-submodule
    GEN git-web--browse
    SUBDIR perl
    GEN git-p4
/usr/local/bin/perl Makefile.PL PREFIX='/usr/local' INSTALL_BASE=''
--localedir='/usr/local/share/locale'
    AR libgit.a
    LINK git-credential-store
    LINK git-daemon
    LINK git-fast-import
libgit.a(grep.o): In function `pcre1match':
grep.c:(.text+0x1219): undefined reference to `pcre_jit_exec'
collect2: error: ld returned 1 exit status
make: *** [Makefile:2145: git-credential-store] Error 1
make: *** Waiting for unfinished jobs....
libgit.a(grep.o): In function `pcre1match':
grep.c:(.text+0x1219): undefined reference to `pcre_jit_exec'
collect2: error: ld returned 1 exit status
make: *** [Makefile:2145: git-fast-import] Error 1
libgit.a(grep.o): In function `pcre1match':
grep.c:(.text+0x1219): undefined reference to `pcre_jit_exec'
collect2: error: ld returned 1 exit status
make: *** [Makefile:2145: git-daemon] Error 1
Generating a Unix-style perl.mak
Writing perl.mak for Git
Writing MYMETA.yml and MYMETA.json
    * new build flags
    CC credential-store.o
    CC common-main.o
    CC abspath.o
    CC advice.o
    CC alias.o
    CC alloc.o
    CC apply.o
    CC archive.o
    CC archive-tar.o
    CC archive-zip.o
    CC argv-array.o
    CC attr.o
    CC base85.o
    CC bisect.o
    CC blame.o
    CC blob.o
    CC branch.o
    CC bulk-checkin.o
    CC bundle.o
    CC cache-tree.o
    CC color.o
    CC column.o
    CC combine-diff.o
    CC commit.o
    CC compat/obstack.o
    CC compat/terminal.o
    CC config.o
    CC connect.o
    CC connected.o
    CC convert.o
    CC copy.o
    CC credential.o
    CC csum-file.o
    CC ctype.o
    CC date.o
    CC decorate.o
    CC diffcore-break.o
    CC diffcore-delta.o
    CC diffcore-order.o
    CC diffcore-pickaxe.o
    CC diffcore-rename.o
    CC diff-delta.o
    CC diff-lib.o
    CC diff-no-index.o
    CC diff.o
    CC dir.o
    CC dir-iterator.o
    CC editor.o
    CC entry.o
    CC environment.o
    CC ewah/bitmap.o
    CC ewah/ewah_bitmap.o
    CC ewah/ewah_io.o
    CC ewah/ewah_rlw.o
    CC exec_cmd.o
    CC fetch-pack.o
    CC fsck.o
    CC gettext.o
    CC gpg-interface.o
    CC graph.o
    CC grep.o
    CC hashmap.o
    CC help.o
    CC hex.o
    CC ident.o
    CC kwset.o
    CC levenshtein.o
    CC line-log.o
    CC line-range.o
    CC list-objects.o
    CC ll-merge.o
    CC lockfile.o
    CC log-tree.o
    CC mailinfo.o
    CC mailmap.o
    CC match-trees.o
    CC merge.o
    CC merge-blobs.o
    CC merge-recursive.o
    CC mergesort.o
    CC mru.o
    CC name-hash.o
    CC notes.o
    CC notes-cache.o
    CC notes-merge.o
    CC notes-utils.o
    CC object.o
    CC oidset.o
    CC pack-bitmap.o
    CC pack-bitmap-write.o
    CC pack-check.o
    CC pack-objects.o
    CC pack-revindex.o
    CC pack-write.o
    CC pager.o
    CC parse-options.o
    CC parse-options-cb.o
    CC patch-delta.o
    CC patch-ids.o
    CC path.o
    CC pathspec.o
    CC pkt-line.o
    CC preload-index.o
    CC pretty.o
    CC prio-queue.o
    CC progress.o
    CC prompt.o
    CC quote.o
    CC reachable.o
    CC read-cache.o
    CC reflog-walk.o
    CC refs.o
    CC refs/files-backend.o
    CC refs/iterator.o
    CC refs/ref-cache.o
    CC ref-filter.o
    CC remote.o
    CC replace_object.o
    CC repository.o
    CC rerere.o
    CC resolve-undo.o
    CC revision.o
    CC run-command.o
    CC send-pack.o
    CC sequencer.o
    CC server-info.o
    CC setup.o
    CC sha1-array.o
    CC sha1-lookup.o
    CC sha1_file.o
    CC sha1_name.o
    CC shallow.o
    CC sideband.o
    CC sigchain.o
    CC split-index.o
    CC strbuf.o
    CC streaming.o
    CC string-list.o
    CC submodule.o
    CC submodule-config.o
    CC sub-process.o
    CC symlinks.o
    CC tag.o
    CC tempfile.o
    CC tmp-objdir.o
    CC trace.o
    CC trailer.o
    CC transport.o
    CC transport-helper.o
    CC tree-diff.o
    CC tree.o
    CC tree-walk.o
    CC unpack-trees.o
    CC url.o
    CC urlmatch.o
    CC usage.o
    CC userdiff.o
    CC utf8.o
    CC varint.o
    CC version.o
    CC versioncmp.o
    CC walker.o
    CC wildmatch.o
    CC worktree.o
    CC wrapper.o
    CC write_or_die.o
    CC ws.o
    CC wt-status.o
    CC xdiff-interface.o
    CC zlib.o
    CC unix-socket.o
    CC sha1dc/sha1.o
    CC sha1dc/ubc_check.o
    CC thread-utils.o
    CC compat/fopen.o
    CC compat/strlcpy.o
    CC compat/qsort_s.o
    AR libgit.a
    CC xdiff/xdiffi.o
    CC xdiff/xprepare.o
    CC xdiff/xutils.o
    CC xdiff/xemit.o
    CC xdiff/xmerge.o
    CC xdiff/xpatience.o
    CC xdiff/xhistogram.o
    AR xdiff/lib.a
    LINK git-credential-store
libgit.a(grep.o): In function `pcre1match':
grep.c:(.text+0x1219): undefined reference to `pcre_jit_exec'
collect2: error: ld returned 1 exit status
make: *** [Makefile:2145: git-credential-store] Error 1

```

## Jeff King, 2017-10-12 20:10

Subject: Re: undefined reference to `pcre_jit_exec'
Message-ID: <20171012201023.wrfbs7p7lups5glz@sigill.intra.peff.net>
URL: https://gitlist.dev/e/20171012201023.wrfbs7p7lups5glz%40sigill.intra.peff.net
In-Reply-To: <CAH8yC8mvG3bSpgshHay7B0SSyAafWLrPTtVZRuq2cShn9xQ9JA@mail.gmail.com>

```
On Thu, Oct 12, 2017 at 04:06:11PM -0400, Jeffrey Walton wrote:

> I have a script to build Git on some old platforms to ease testing.
> Old platforms include CentOS 5. The script is available at
> https://github.com/noloader/Build-Scripts/blob/master/build-ssh.sh.
> 
> It looks like something got knocked loose recently. I'm seeing several
> of these when building with PCRE 8.41 with Git 2.14.2. Old and new
> platforms are witnessing it. I observe it on CentOS 5 with GCC 4.1;
> and Fedora 26 with GCC 7.2.
> 
>     ...
>     LINK git-credential-store
> libgit.a(grep.o): In function `pcre1match':
> grep.c:(.text+0x1219): undefined reference to `pcre_jit_exec'
> collect2: error: ld returned 1 exit status
> make: *** [Makefile:2145: git-credential-store] Error 1

Maybe:

  $ git grep -h -B5 -A1 pcre_jit Makefile
  # When using USE_LIBPCRE1, define NO_LIBPCRE1_JIT if the PCRE v1
  # library is compiled without --enable-jit. We will auto-detect
  # whether the version of the PCRE v1 library in use has JIT support at
  # all, but we unfortunately can't auto-detect whether JIT support
  # hasn't been compiled in in an otherwise JIT-supporting version. If
  # you have link-time errors about a missing `pcre_jit_exec` define
  # this, or recompile PCRE v1 with --enable-jit.

It looks like autoconf turns on USE_LIBPCRE1, but isn't smart enough to
test NO_LIBPCRE1_JIT.

-Peff

```

## Jeffrey Walton, 2017-10-12 20:34

Subject: Re: undefined reference to `pcre_jit_exec'
Message-ID: <CAH8yC8nHpdA+fX3pcaLRzEYwTCmoxF3NKSh6SUkORZuEvg0JGA@mail.gmail.com>
URL: https://gitlist.dev/e/CAH8yC8nHpdA%2BfX3pcaLRzEYwTCmoxF3NKSh6SUkORZuEvg0JGA%40mail.gmail.com
In-Reply-To: <20171012201023.wrfbs7p7lups5glz@sigill.intra.peff.net>

```
On Thu, Oct 12, 2017 at 4:10 PM, Jeff King <peff@peff.net> wrote:
> On Thu, Oct 12, 2017 at 04:06:11PM -0400, Jeffrey Walton wrote:
>
>> I have a script to build Git on some old platforms to ease testing.
>> Old platforms include CentOS 5. The script is available at
>> https://github.com/noloader/Build-Scripts/blob/master/build-ssh.sh.
>>
>> It looks like something got knocked loose recently. I'm seeing several
>> of these when building with PCRE 8.41 with Git 2.14.2. Old and new
>> platforms are witnessing it. I observe it on CentOS 5 with GCC 4.1;
>> and Fedora 26 with GCC 7.2.
>>
>>     ...
>>     LINK git-credential-store
>> libgit.a(grep.o): In function `pcre1match':
>> grep.c:(.text+0x1219): undefined reference to `pcre_jit_exec'
>> collect2: error: ld returned 1 exit status
>> make: *** [Makefile:2145: git-credential-store] Error 1
>
> Maybe:
>
>   $ git grep -h -B5 -A1 pcre_jit Makefile
>   # When using USE_LIBPCRE1, define NO_LIBPCRE1_JIT if the PCRE v1
>   # library is compiled without --enable-jit. We will auto-detect
>   # whether the version of the PCRE v1 library in use has JIT support at
>   # all, but we unfortunately can't auto-detect whether JIT support
>   # hasn't been compiled in in an otherwise JIT-supporting version. If
>   # you have link-time errors about a missing `pcre_jit_exec` define
>   # this, or recompile PCRE v1 with --enable-jit.

Ah, thanks. A quick search did not find that comment. And it did not
occur to me to re-run --help to read about it.

> It looks like autoconf turns on USE_LIBPCRE1, but isn't smart enough to
> test NO_LIBPCRE1_JIT.

If Git wants Jit, then I am inclined to configure PCRE to provide it.

A quick question if you happen to know... Does PCRE Jit cause a loss
of NX-stacks? If it causes a loss of NX-stacks, then I think I prefer
to disable it.

Jeff

```

## Jeff King, 2017-10-12 20:38

Subject: Re: undefined reference to `pcre_jit_exec'
Message-ID: <20171012203832.ui52j7cdrztc6vhs@sigill.intra.peff.net>
URL: https://gitlist.dev/e/20171012203832.ui52j7cdrztc6vhs%40sigill.intra.peff.net
In-Reply-To: <CAH8yC8nHpdA+fX3pcaLRzEYwTCmoxF3NKSh6SUkORZuEvg0JGA@mail.gmail.com>

```
On Thu, Oct 12, 2017 at 04:34:38PM -0400, Jeffrey Walton wrote:

> > It looks like autoconf turns on USE_LIBPCRE1, but isn't smart enough to
> > test NO_LIBPCRE1_JIT.
> 
> If Git wants Jit, then I am inclined to configure PCRE to provide it.

It does make things faster. OTOH, we lived for many years without it, so
certainly it's not the end of the world to build without it.

There are some numbers in the commit message of fbaceaac47 (grep: add
support for the PCRE v1 JIT API, 2017-05-25).

> A quick question if you happen to know... Does PCRE Jit cause a loss
> of NX-stacks? If it causes a loss of NX-stacks, then I think I prefer
> to disable it.

I don't know. Ævar (cc'd) might.

-Peff

```

## Jeffrey Walton, 2017-10-12 21:00

Subject: Re: undefined reference to `pcre_jit_exec'
Message-ID: <CAH8yC8kSpON5UP=pfsGXQ9JhhZOHVPetFHbr0BqBPnoYzj4Hog@mail.gmail.com>
URL: https://gitlist.dev/e/CAH8yC8kSpON5UP%3DpfsGXQ9JhhZOHVPetFHbr0BqBPnoYzj4Hog%40mail.gmail.com
In-Reply-To: <20171012203832.ui52j7cdrztc6vhs@sigill.intra.peff.net>

```
On Thu, Oct 12, 2017 at 4:38 PM, Jeff King <peff@peff.net> wrote:
> On Thu, Oct 12, 2017 at 04:34:38PM -0400, Jeffrey Walton wrote:
>
>> > It looks like autoconf turns on USE_LIBPCRE1, but isn't smart enough to
>> > test NO_LIBPCRE1_JIT.
>>
>> If Git wants Jit, then I am inclined to configure PCRE to provide it.
>
> It does make things faster. OTOH, we lived for many years without it, so
> certainly it's not the end of the world to build without it.
>
> There are some numbers in the commit message of fbaceaac47 (grep: add
> support for the PCRE v1 JIT API, 2017-05-25).
>
>> A quick question if you happen to know... Does PCRE Jit cause a loss
>> of NX-stacks? If it causes a loss of NX-stacks, then I think I prefer
>> to disable it.
>
> I don't know. Ævar (cc'd) might.

Thanks. Building PCRE with Jit enabled results in:

$ readelf -l /usr/local/libexec/git-core/git-credential-re| grep -i -A1 stack
  GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
                 0x0000000000000000 0x0000000000000000  RW     10

So it looks like the NX-stacks were not lost.

Thanks again.

Jeff

```

## Ævar Arnfjörð Bjarmason, 2017-10-12 21:05

Subject: Re: undefined reference to `pcre_jit_exec'
Message-ID: <874lr46prx.fsf@evledraar.booking.com>
URL: https://gitlist.dev/e/874lr46prx.fsf%40evledraar.booking.com
In-Reply-To: <20171012203832.ui52j7cdrztc6vhs@sigill.intra.peff.net>

```

On Thu, Oct 12 2017, Jeff King jotted:

> On Thu, Oct 12, 2017 at 04:34:38PM -0400, Jeffrey Walton wrote:
>
>> > It looks like autoconf turns on USE_LIBPCRE1, but isn't smart enough to
>> > test NO_LIBPCRE1_JIT.
>>
>> If Git wants Jit, then I am inclined to configure PCRE to provide it.
>
> It does make things faster. OTOH, we lived for many years without it, so
> certainly it's not the end of the world to build without it.
>
> There are some numbers in the commit message of fbaceaac47 (grep: add
> support for the PCRE v1 JIT API, 2017-05-25).
>
>> A quick question if you happen to know... Does PCRE Jit cause a loss
>> of NX-stacks? If it causes a loss of NX-stacks, then I think I prefer
>> to disable it.
>
> I don't know. Ævar (cc'd) might.

Sorry, no idea. I do see some references to that in sljit (which pcre
JIT uses), but haven't tried this myself. From what I understand of how
NX works it should fail really fast if it doesn't, so it would be cool
if you could try it and report if it works.

```