Add perf-test for wildmatch.
* ab/perf-wildmatch:
perf: add test showing exponential growth in path globbing
perf: add function to setup a fresh test repo
Simplify parse_pathspec() codepath and stop it from looking at the
default in-core index.
* bw/pathspec-sans-the-index:
pathspec: convert find_pathspecs_matching_against_index to take an index
pathspec: remove PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP
ls-files: prevent prune_cache from overeagerly pruning submodules
pathspec: remove PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE flag
submodule: add die_in_unpopulated_submodule function
pathspec: provide a more descriptive die message
"git describe --contains" penalized light-weight tags so much that
they were almost never considered. Instead, give them about the
same chance to be considered as an annotated tag that is the same
age as the underlying commit would.
* jc/name-rev-lw-tag:
name-rev: favor describing with tags and use committer date to tiebreak
name-rev: refactor logic to see if a new candidate is a better name
Using the is_missing_file_error() helper introduced in the previous
step, update all hits from
$ git grep -e ENOENT --and -e ENOTDIR
There are codepaths that only check ENOENT, and it is possible that
some of them should be checking both. Updating them is kept out of
this step deliberately, as we do not want to change behaviour in this
step.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our code often opens a path to an optional file, to work on its
contents when we can successfully open it. We can ignore a failure
to open if such an optional file does not exist, but we do want to
report a failure in opening for other reasons (e.g. we got an I/O
error, or the file is there, but we lack the permission to open).
The exact errors we need to ignore are ENOENT (obviously) and
ENOTDIR (less obvious). Instead of repeating comparison of errno
with these two constants, introduce a helper function to do so.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fixes the test by changing "branch.s/s/dummy" to "branch.s/s.dummy" which is
the right way of accessing config key "branch.s/s.dummy". Purpose of
this test is to confirm that this key doesn't exist after the branch
"s/s" has been renamed to "s".
Earlier it was trying to access invalid config key and hence was getting
an error. However, this wasn't caught because we were expecting the
command to fail for other reason as mentioned above.
Signed-off-by: Sahil Dua <sahildua2305@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Tag objects, which are not reachable from any ref, that point at
missing objects were mishandled by "git gc" and friends (they
should silently be ignored instead)
* jk/ignore-broken-tags-when-ignoring-missing-links:
revision.c: ignore broken tags with ignore_missing_links
A test allowed both "git push" and "git receive-pack" on the other
end write their traces into the same file. This is OK on platforms
that allows atomically appending to a file opened with O_APPEND,
but on other platforms led to a mangled output, causing
intermittent test failures. This has been fixed by disabling
traces from "receive-pack" in the test.
* jk/alternate-ref-optim:
t5400: avoid concurrent writes into a trace file
"git interpret-trailers", when used as GIT_EDITOR for "git commit
-v", looked for and appended to a trailer block at the very end,
i.e. at the end of the "diff" output. The command has been
corrected to pay attention to the cut-mark line "commit -v" adds to
the buffer---the real trailer block should appear just before it.
* bm/interpret-trailers-cut-line-is-eom:
interpret-trailers: honor the cut line
Regression fix to topic recently merged to 'master'.
* pw/rebase-i-regression-fix:
rebase -i: add missing newline to end of message
rebase -i: silence stash apply
rebase -i: fix reflog message
"git for-each-ref --format=..." with %(HEAD) in the format used to
resolve the HEAD symref as many times as it had processed refs,
which was wasteful, and "git branch" shared the same problem.
* kn/ref-filter-branch-list:
ref-filter: resolve HEAD when parsing %(HEAD) atom
A few http:// links that are redirected to https:// in the
documentation have been updated to https:// links.
* jk/update-links-in-docs:
doc: use https links to Wikipedia to avoid http redirects
Git sometimes gives an advice in a rhetorical question that does
not require an answer, which can confuse new users and non native
speakers. Attempt to rephrase them.
* ja/do-not-ask-needless-questions:
git-filter-branch: be more direct in an error message
read-tree -m: make error message for merging 0 trees less smart aleck
usability: don't ask questions if no reply is required
Clarify documentation for include.path and includeIf.<condition>.path
configuration variables.
* jk/doc-config-include:
docs/config: consistify include.path examples
docs/config: avoid the term "expand" for includes
docs/config: give a relative includeIf example
docs/config: clarify include/includeIf relationship
Introduce the BUG() macro to improve die("BUG: ...").
* jk/bug-to-abort:
usage: add NORETURN to BUG() function definitions
config: complain about --local outside of a git repo
setup_git_env: convert die("BUG") to BUG()
usage.c: add BUG() function
Make sure our tests would pass when the sources are checked out
with "platform native" line ending convention by default on
Windows. Some "text" files out tests use and the test scripts
themselves that are meant to be run with /bin/sh, ought to be
checked out with eol=LF even on Windows.
* js/eol-on-ourselves:
t4051: mark supporting files as requiring LF-only line endings
Fix the remaining tests that failed with core.autocrlf=true
t3901: move supporting files into t/t3901/
completion: mark bash script as LF-only
git-new-workdir: mark script as LF-only
Fix build with core.autocrlf=true
"git read-tree -m" (no tree-ish) gave a nonsense suggestion "use
--empty if you want to clear the index". With "-m", such a request
will still fail anyway, as you'd need to name at least one tree-ish
to be merged.
* jc/read-tree-empty-with-m:
read-tree: "read-tree -m --empty" does not make sense
"pack-objects" can stream a slice of an existing packfile out when
the pack bitmap can tell that the reachable objects are all needed
in the output, without inspecting individual objects. This
strategy however would not work well when "--local" and other
options are in use, and need to be disabled.
* jk/disable-pack-reuse-when-broken:
t5310: fix "; do" style
pack-objects: disable pack reuse for object-selection options
Conversion from uchar[20] to struct object_id continues.
* bc/object-id: (53 commits)
object: convert parse_object* to take struct object_id
tree: convert parse_tree_indirect to struct object_id
sequencer: convert do_recursive_merge to struct object_id
diff-lib: convert do_diff_cache to struct object_id
builtin/ls-tree: convert to struct object_id
merge: convert checkout_fast_forward to struct object_id
sequencer: convert fast_forward_to to struct object_id
builtin/ls-files: convert overlay_tree_on_cache to object_id
builtin/read-tree: convert to struct object_id
sha1_name: convert internals of peel_onion to object_id
upload-pack: convert remaining parse_object callers to object_id
revision: convert remaining parse_object callers to object_id
revision: rename add_pending_sha1 to add_pending_oid
http-push: convert process_ls_object and descendants to object_id
refs/files-backend: convert many internals to struct object_id
refs: convert struct ref_update to use struct object_id
ref-filter: convert some static functions to struct object_id
Convert struct ref_array_item to struct object_id
Convert the verify_pack callback to struct object_id
Convert lookup_tag to struct object_id
...
Plug some leaks and updates internal API used to implement the
split index feature to make it easier to avoid such a leak in the
future.
* nd/split-index-unshare:
p3400: add perf tests for rebasing many changes
split-index: add and use unshare_split_index()
"git repack" learned to accept the --threads=<n> option and pass it
to pack-objects.
* jc/repack-threads:
repack: accept --threads=<n> and pass it down to pack-objects
API update.
* bw/dir-c-stops-relying-on-the-index:
dir: convert fill_directory to take an index
dir: convert read_directory to take an index
dir: convert read_directory_recursive to take an index
dir: convert open_cached_dir to take an index
dir: convert is_excluded to take an index
dir: convert prep_exclude to take an index
dir: convert add_excludes to take an index
dir: convert is_excluded_from_list to take an index
dir: convert last_exclude_matching_from_list to take an index
dir: convert dir_add* to take an index
dir: convert get_dtype to take index
dir: convert directory_exists_in_index to take index
dir: convert read_skip_worktree_file_from_index to take an index
dir: stop using the index compatibility macros
"git checkout --recurse-submodules" did not quite work with a
submodule that itself has submodules.
* sb/checkout-recurse-submodules:
submodule: properly recurse for read-tree and checkout
submodule: avoid auto-discovery in new working tree manipulator code
submodule_move_head: reuse child_process structure for futher commands
The looks_like_pathspec() check is much cheaper than
check_filename(), which actually stats the file. Since
either is sufficient for our return value, we should do the
cheaper one first, potentially short-circuiting the other.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For commands that take revisions and pathspecs, magic
pathspecs like ":(exclude)foo" require the user to specify
a disambiguating "--", since they do not match a file in the
filesystem, like:
git grep foo -- :(exclude)bar
This makes them more annoying to use than they need to be.
We loosened the rules for wildcards in 28fcc0b71 (pathspec:
avoid the need of "--" when wildcard is used, 2015-05-02).
Let's do the same for pathspecs with long-form magic.
We already handle the short-forms ":/" and ":^" specially in
check_filename(), so we don't need to handle them here. And
in fact, we could do the same with long-form magic, parsing
out the actual filename and making sure it exists. But there
are a few reasons not to do it that way:
- the parsing gets much more complicated, and we'd want to
hand it off to the pathspec code. But that code isn't
ready to do this kind of speculative parsing (it's happy
to die() when it sees a syntactically invalid pathspec).
- not all pathspec magic maps to a filesystem path. E.g.,
:(attr) should be treated as a pathspec regardless of
what is in the filesystem
- we can be a bit looser with ":(" than with the
short-form ":/", because it is much less likely to have
a false positive. Whereas ":/" also means "search for a
commit with this regex".
Note that because the change is in verify_filename() and not
in its helper check_filename(), this doesn't affect the
verify_non_filename() case. I.e., if an item that matches
our new rule doesn't resolve as an object, we may fallback
to treating it as a pathspec (rather than complaining it
doesn't exist). But if it does resolve (e.g., as a file in
the index that starts with an open-paren), we won't then
complain that it's also a valid pathspec. This matches the
wildcard-exception behavior.
And of course in either case, one can always insert the "--"
to get more precise results.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We special-case "git log :/foo" to work when "foo" exists in
the working tree. But :^ (and its alias :!) do not get the
same treatment, requiring the user to supply a
disambiguating "--". Let's make them work without requiring
the user to type the "--".
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This avoids some magic numbers (and we'll be adding more
similar calls in a minute).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We handle arguments with the ":/" pathspec magic specially,
making sure the name exists at the top-level. We'll want to
handle more pathspec magic in future patches, so let's do a
little rearranging to make that easier.
Instead of relying on an if/else cascade to avoid the
prefix_filename() call, we'll just set prefix to NULL.
Likewise, we'll get rid of the "name" variable entirely, and
just push the "arg" pointer forward to skip past the magic.
That means by the time we get to the prefix-handling, we're
set up appropriately whether we saw ":/" or not.
Note that this does impact the final error message we
produce when stat() fails, as it shows "arg" (which we'll
have modified to skip magic and include the prefix). This is
a good thing; the original message would say something like
"failed to stat ':/foo'", which is confusing (we tried to
stat "foo").
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The DWIM magic in check_filename() doesn't just recognize
":/". It actually makes sure that the file it points to
exists. t4208 checks only the case where the path is
present, not the opposite. Since the next patches will be
touching this area, let's add a test to make sure it
continues working.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove a test line that's exactly the same as the preceding
line.
This was brought in in commit feabcc173b ("Integrate wildmatch to
git", 2012-10-15), these tests are originally copied from rsync.git,
but the duplicate line was never present there, so must have just
snuck in during integration with git by accident.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function `set_ident` in `filter-branch` exported the variables
GIT_(AUTHOR|COMMITTER)_(NAME|EMAIL|DATE) at least since 6f6826c52b in 2007.
Therefore the filter scripts don't need to re-eport them again.
Signed-off-by: Andreas Heiduk <asheiduk@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Amend my change earlier in this series ("grep: add support for the
PCRE v1 JIT API", 2017-04-11) to un-break the build on PCRE v1
versions earlier than 8.20.
The 8.20 release was the first release to have JIT & pcre_jit_stack in
the headers, so a mock type needs to be provided for it on those
releases.
Now git should compile with all PCRE versions that it supported before
my JIT change.
I've tested it as far back as version 7.5 released on 2008-01-10, once
I got down to version 7.0 it wouldn't build anymore with GCC 7.1.1,
and I couldn't be bothered to anything older than 7.5 as I'm confident
that if the build breaks on those older versions it's not because of
my JIT change.
See the "un-break" change in this series ("grep: un-break building
with PCRE < 8.32", 2017-05-10) for why this isn't squashed into the
main PCRE JIT commit.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Amend my change earlier in this series ("grep: add support for the
PCRE v1 JIT API", 2017-04-11) to un-break the build on PCRE v1
versions earlier than 8.32.
The JIT support was added in version 8.20 released on 2011-10-21, but
it wasn't until 8.32 released on 2012-11-30 that the fast code path to
use the JIT via pcre_jit_exec() was added[1] (see also [2]).
This means that versions 8.20 through 8.31 could still use the JIT,
but supporting it on those versions would add to the already verbose
macro soup around JIT support it, and I don't expect that the use-case
of compiling a brand new git against a 5 year old PCRE is particularly
common, and if someone does that they can just get the existing
pre-JIT slow codepath.
So just take the easy way out and disable the JIT on any version older
than 8.32.
The reason this change isn't part of the initial change PCRE JIT
support is to have a cleaner history showing which parts of the
implementation are only used for ancient PCRE versions. This also
makes it easier to revert this change if we ever decide to stop
supporting those old versions.
1. http://www.pcre.org/original/changelog.txt ("28. Introducing a
native interface for JIT. Through this interface, the
compiled[...]")
2. https://bugs.exim.org/show_bug.cgi?id=2121
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the grep PCRE v1 code to use JIT when available. When PCRE
support was initially added in commit 63e7e9d8b6 ("git-grep: Learn
PCRE", 2011-05-09) PCRE had no JIT support, it was integrated into
8.20 released on 2011-10-21.
Enabling JIT support usually improves performance by more than
40%. The pattern compilation times are relatively slower, but those
relative numbers are tiny, and are easily made back in all but the
most trivial cases of grep. Detailed benchmarks & overview of
compilation times is at: http://sljit.sourceforge.net/pcre.html
With this change the difference in a t/perf/p7820-grep-engines.sh run
is, with just the /perl/ tests shown:
$ GIT_PERF_REPEAT_COUNT=30 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_MAKE_OPTS='-j8 USE_LIBPCRE=YesPlease CC=~/perl5/installed/bin/gcc NO_R_TO_GCC_LINKER=YesPlease CFLAGS=-O3 LIBPCREDIR=/home/avar/g/pcre/inst LDFLAGS=-Wl,-rpath,/home/avar/g/pcre/inst/lib' ./run HEAD~ HEAD p7820-grep-engines.sh
Test HEAD~ HEAD
---------------------------------------------------------------------------------------
7820.3: perl grep 'how.to' 0.35(1.11+0.43) 0.23(0.42+0.46) -34.3%
7820.7: perl grep '^how to' 0.64(2.71+0.36) 0.27(0.66+0.44) -57.8%
7820.11: perl grep '[how] to' 0.63(2.51+0.42) 0.33(0.98+0.39) -47.6%
7820.15: perl grep '(e.t[^ ]*|v.ry) rare' 1.17(5.61+0.35) 0.34(1.08+0.46) -70.9%
7820.19: perl grep 'm(ú|u)lt.b(æ|y)te' 0.43(1.52+0.44) 0.30(0.88+0.42) -30.2%
The conditional support for JIT is implemented as suggested in the
pcrejit(3) man page. E.g. defining PCRE_STUDY_JIT_COMPILE to 0 if it's
not present.
The implementation is relatively verbose because even if
PCRE_CONFIG_JIT is defined only a call to pcre_config() can determine
if the JIT is available, and if so the faster pcre_jit_exec() function
should be called instead of pcre_exec(), and a different (but not
complimentary!) function needs to be called to free pcre1_extra_info.
There's no graceful fallback if pcre_jit_stack_alloc() fails under
PCRE_CONFIG_JIT, instead the program will simply abort. I don't think
this is worth handling gracefully, it'll only fail in cases where
malloc() doesn't work, in which case we're screwed anyway.
That there's no assignment of `p->pcre1_jit_on = 0` when
PCRE_CONFIG_JIT isn't defined isn't a bug. The create_grep_pat()
function allocates the grep_pat allocates it with calloc(), so it's
guaranteed to be 0 when PCRE_CONFIG_JIT isn't defined.
I you're bisecting and find this change, check that your PCRE isn't
older than 8.32. This change intentionally broke really old versions
of PCRE, but that's fixed in follow-up commits.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a short -P option as a synonym for the longer --perl-regexp, for
consistency with the options the corresponding grep invocations
accept.
This was intentionally omitted in commit 727b6fc3ed ("log --grep:
accept --basic-regexp and --perl-regexp", 2012-10-03) for unspecified
future use.
Make it consistent with "grep" rather than to keep it open for future
use, and to avoid the confusion of -P meaning different things for
grep & log, as is the case with the -G option.
As noted in the aforementioned commit the --basic-regexp option can't
have a corresponding -G argument, as the log command already uses that
for -G<regex>.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Skip the administrative overhead of using pthreads when only using one
thread. Instead take the non-threaded path which would be taken under
NO_PTHREADS.
The threading support was initially added in commit
5b594f457a ("Threaded grep", 2010-01-25) with a hardcoded compile-time
number of 8 threads. Later the number of threads was made configurable
in commit 89f09dd34e ("grep: add --threads=<num> option and
grep.threads configuration", 2015-12-15).
That change did not add any special handling for --threads=1. Now we
take a slightly faster path by skipping thread handling entirely when
1 thread is requested.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the pattern compilation logic under threading so that grep
doesn't compile a pattern it never ends up using on the non-threaded
code path, only to compile it again N times for N threads which will
each use their own copy, ignoring the initially compiled pattern.
This redundant compilation dates back to the initial introduction of
the threaded grep in commit 5b594f457a ("Threaded grep",
2010-01-25).
There was never any reason for doing this redundant work other than an
oversight in the initial commit. Jeff King suggested on-list in
<20170414212325.fefrl3qdjigwyitd@sigill.intra.peff.net> that this
might be needed to check the pattern for sanity before threaded
execution commences.
That's not the case. The pattern is compiled under threading in
start_threads() before any concurrent execution has started by calling
pthread_create(), so if the pattern contains an error we still do the
right thing. I.e. die with one error before any threaded execution has
commenced, instead of e.g. spewing out an error for each N threads,
which could be a regression a change like this might inadvertently
introduce.
This change is not meant as an optimization, any performance gains
from this are in the hundreds to thousands of nanoseconds at most. If
we wanted more performance here we could just re-use the compiled
patterns in multiple threads (regcomp(3) is thread-safe), or partially
re-use them and the associated structures in the case of later PCRE
JIT changes.
Rather, it's just to make the code easier to reason about. It's
confusing to debug this under threading & non-threading when the
threading codepaths redundantly compile a pattern which is never used.
The reason the patterns are recompiled is as a side-effect of
duplicating the whole grep_opt structure, which is not thread safe,
writable, and munged during execution. The grep_opt structure then
points to the grep_pat structure where pattern or patterns are stored.
I looked into e.g. splitting the API into some "do & alloc threadsafe
stuff", "spawn thread", "do and alloc non-threadsafe stuff", but the
execution time of grep_opt_dup() & pattern compilation is trivial
compared to actually executing the grep, so there was no point. Even
with the more expensive JIT changes to follow the most expensive PCRE
patterns take something like 0.0X milliseconds to compile at most[1].
The undocumented --debug mode added in commit 17bf35a3c7 ("grep: teach
--debug option to dump the parse tree", 2012-09-13) still works
properly with this change. It only emits debugging info during pattern
compilation, which is now dumped by the pattern compiled just before
the first thread is started.
1. http://sljit.sourceforge.net/pcre.html
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the grep_{lock,unlock} functions to assert that num_threads is
true, instead of only locking & unlocking the pthread mutex lock when
it is.
These functions are never called when num_threads isn't true, this
logic has gone through multiple iterations since the initial
introduction of grep threading in commit 5b594f457a ("Threaded grep",
2010-01-25), but ever since then they'd only be called if num_threads
was true, so this check made the code confusing to read.
Replace the check with an assertion, so that it's clear to the reader
that this code path is never taken unless we're spawning threads.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a warning about missing thread support when grep.threads or
--threads is set to a non 0 (default) or 1 (no parallelism) value
under NO_PTHREADS=YesPlease.
This is for consistency with the index-pack & pack-objects commands,
which also take a --threads option & are configurable via
pack.threads, and have long warned about the same under
NO_PTHREADS=YesPlease.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a buggy warning about threads under NO_PTHREADS=YesPlease. Due to
re-using the delta_search_threads variable for both the state of the
"pack.threads" config & the --threads option, setting "pack.threads"
but not supplying --threads would trigger the warning for both
"pack.threads" & --threads.
Solve this bug by resetting the delta_search_threads variable in
git_pack_config(), it might then be set by --threads again and be
subsequently warned about, as the test I'm changing here asserts.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a test for the warning that's emitted when --threads or
pack.threads is provided under NO_PTHREADS=YesPlease. This uses the
new PTHREADS prerequisite.
The assertion for C_LOCALE_OUTPUT in the latter test is currently
redundant, since unlike index-pack the pack-objects warnings aren't
i18n'd. However they might be changed to be i18n'd in the future, and
there's no harm in future-proofing the test.
There's an existing bug in the implementation of pack-objects which
this test currently tests for as-is. Details about the bug & the fix
are included in a follow-up change.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a PTHREADS prerequisite which is false when git is compiled with
NO_PTHREADS=YesPlease.
There's lots of custom code that runs when threading isn't available,
but before this prerequisite there was no way to test it.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the is_fixed() function which are currently only used in
compile_regexp() earlier so it can be used in the PCRE family of
functions in a later change.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>