Until now postgres built extension libraries with global visibility, i.e.
exporting all symbols. On the one platform where that behavior is not
natively available, namely windows, we emulate it by analyzing the input files
to the shared library and exporting all the symbols therein.
Not exporting all symbols is actually desirable, as it can improve loading
speed, reduces the likelihood of symbol conflicts and can improve intra
extension library function call performance. It also makes the non-windows
builds more similar to windows builds.
Additionally, with meson implementing the export-all-symbols behavior for
windows, turns out to be more verbose than desirable.
This patch adds support for hiding symbols by default and, to counteract that,
explicit symbol visibility annotation for compilers that support
__attribute__((visibility("default"))) and -fvisibility=hidden. That is
expected to be most, if not all, compilers except msvc (for which we already
support explicit symbol export annotations).
Now that extension library symbols are explicitly exported, we don't need to
export all symbols on windows anymore, hence remove that behavior from
src/tools/msvc. The supporting code can't be removed, as we still need to
export all symbols from the main postgres binary.
Author: Andres Freund <andres@anarazel.de>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/20211101020311.av6hphdl6xbjbuif@alap3.anarazel.de
No members of the buildfarm are using this version of Visual Studio,
resulting in all the code cleaned up here as being mostly dead, and
VS2017 is the oldest version still supported.
More versions could be cut, but the gain would be minimal, while
removing only VS2013 has the advantage to remove from the core code all
the dependencies on the value defined by _MSC_VER, where compatibility
tweaks have accumulated across the years mostly around locales and
strtof(), so that's a nice isolated cleanup.
Note that this commit additionally allows a revert of 3154e16. The
versions of Visual Studio now supported range from 2015 to 2022.
Author: Michael Paquier
Reviewed-by: Juan José Santamaría Flecha, Tom Lane, Thomas Munro, Justin
Pryzby
Discussion: https://postgr.es/m/YoH2IMtxcS3ncWn+@paquier.xyz
HP-UX hardware is no longer produced, build farm coverage recently
ended, and there are no known active maintainers targeting this OS.
Since there is a major rewrite of the build system in the pipeline for
PostgreSQL 16, and that requires development, testing and maintainance
for each OS and tool chain, it seems like a good time to drop support
for:
* HP-UX, the operating system.
* HP aCC, the HP-UX native compiler.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Discussion: https://postgr.es/m/1415825.1656893299%40sss.pgh.pa.us
macOS has traditionally used extension .dylib for shared libraries
(used at build time) and .so for dynamically loaded modules (used by
dlopen()). This complicates the build system a bit. Also, Meson uses
.dylib for both, so it would be worth unifying this in order to be
able to get equal build output.
There doesn't appear to be any reason to use any particular extension
for dlopened modules, since dlopen() will accept anything and
PostgreSQL is well-factored to be able to deal with any extension.
Other software packages that I have handy appear to be about 50/50
split on which extension they use for their plugins. So it seems
possible to change this safely.
Discussion: https://www.postgresql.org/message-id/flat/bcc45f78-e3c3-8fb3-7c42-5371b48b5266%40enterprisedb.com
In OpenLDAP 2.5 and later, libldap itself is always thread-safe and
there's never a libldap_r. Our existing coding dealt with that
by assuming it wouldn't find libldap_r if libldap is thread-safe.
But that rule fails to cope if there are multiple OpenLDAP versions
visible, as is likely to be the case on macOS in particular. We'd
end up using shiny new libldap in the backend and a hoary libldap_r
in libpq.
Instead, once we've found libldap, check if it's >= 2.5 (by
probing for a function introduced then) and don't bother looking
for libldap_r if so. While one can imagine library setups that
this'd still give the wrong answer for, they seem unlikely to
occur in practice.
Per report from Peter Eisentraut. Back-patch to all supported branches.
Discussion: https://postgr.es/m/fedacd7c-2a38-25c9-e7ff-dea549d0e979@enterprisedb.com
The test for lz4.h used AC_CHECK_HEADERS, but nothing was using the
resulting symbol HAVE_LZ4_H. Change this to use AC_CHECK_HEADER
instead. This was probably an oversight, seeing that the nearby
similar tests do this correctly.
It emerges that our new zstd code depends on features that were not
present (or at least not enabled by default) in zstd before 1.4.0.
That's already four years old, so there's little reason to try to
make our code work with something older. Instead make configure
check that zstd is at least 1.4.0, and document this requirement.
Justin Pryzby (doc changes by me)
Discussion: https://postgr.es/m/efbd94cd1102f99fd1300e44905ee4a994ee2ef6.camel@gunduz.org
The current implementation supports exactly one IP address in a server
certificate's Common Name, which is brittle (the strings must match
exactly). This patch adds support for IPv4 and IPv6 addresses in a
server's Subject Alternative Names.
Per discussion on-list:
- If the client's expected host is an IP address, we allow fallback to
the Subject Common Name if an iPAddress SAN is not present, even if
a dNSName is present. This matches the behavior of NSS, in
violation of the relevant RFCs.
- We also, counter-intuitively, match IP addresses embedded in dNSName
SANs. From inspection this appears to have been the behavior since
the SAN matching feature was introduced in acd08d76.
- Unlike NSS, we don't map IPv4 to IPv6 addresses, or vice-versa.
Author: Jacob Champion <pchampion@vmware.com>
Co-authored-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Co-authored-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/flat/9f5f20974cd3a4091a788cf7f00ab663d5fcdffe.camel@vmware.com
Move DLSUFFIX from makefiles into header files for all platforms.
Move the DLSUFFIX assignment from src/makefiles/ to src/templates/,
have configure read it, and then substitute it into Makefile.global
and pg_config.h. This avoids the need for all makefile rules that
need it to locally set CPPFLAGS. It also resolves an inconsistent
setup between the two Windows build systems.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/2f9861fb-8969-9005-7518-b8e60f2bead9@enterprisedb.com
When building with sanitizers the sanitizer library provides dlopen, but not
dlsym(), making configure think that -ldl isn't needed. Just checking for
dlsym() ought to suffice, hard to see dlsym() being provided without dlopen()
also being provided.
Backpatch to all branches, for the same reasons as 46ab07ffda.
Reviewed-By: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/20220323173537.ll7klrglnp4gn2um@alap3.anarazel.de
Backpatch: 10-
In particular, perl with $Config{osname} = msys should only be used if
the build target is msys (which is currently buildable but not usable).
For builds targeted at native Windows, perl from the ucrt64 toolchain is
suitable.
Discussion: https://postgr.es/m/20220216210141.5glt5isg5qtwty4c@alap3.anarazel.de
GCC 12 complains that set_stack_base is storing the address of
a local variable in a long-lived pointer. This is an entirely
reasonable warning (indeed, it just helped us find a bug);
but that behavior is intentional here. We can work around it
by using __builtin_frame_address(0) instead of a specific local
variable; that produces an address a dozen or so bytes different,
in my testing, but we don't care about such a small difference.
Maybe someday a compiler lacking that function will start to issue
a similar warning, but we'll worry about that when it happens.
Patch by me, per a suggestion from Andres Freund. Back-patch to
v12, which is as far back as the patch will go without some pain.
(Recently-established project policy would permit a back-patch as
far as 9.2, but I'm disinclined to expend the work until GCC 12
is much more widespread.)
Discussion: https://postgr.es/m/3773792.1645141467@sss.pgh.pa.us
Python 2.7 went EOL 2020-01-01 and the support for Python 2 requires a fair
bit of infrastructure. Therefore we are removing Python 2 support in plpython.
This patch just rejects Python 2 during configure / mkvcbuild.pl. Future
commits will remove the code and infrastructure for Python 2 support and
adjust more of the documentation. This way we can see the buildfarm state
after the removal sooner and we can be sure that failures are due to
desupporting Python 2, rather than caused by infrastructure cleanup.
Reviewed-By: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/20211031184548.g4sxfe47n2kyi55r@alap3.anarazel.de
Some environments may compile with --with-lz4 while the command "lz4"
goes missing, causing two failures in the TAP tests of pg_verifybackup
(008_untar.pl and 010_client_untar.pl) as the code assumed that the
command always existed with a hardcoded value in src/Makefile.global.
Rather than this method, this adds a ./configure check based on
PGAC_PATH_PROGS() to find automatically the command and get an absolute
path to it.
Both tests need to be adjusted for the case where the command does not
exist, actually, as Makefile.global would set now LZ4 to an empty value
in this case. The TAP tests of pg_receivewal already do that.
Per report from buildfarm member copperhead, as an effect of dab2984.
The origin of the failure is actually babbbb5 that did not centralize
the check for the existence of a "lz4" command at ./configure to shave a
few cycles. Note that one just needs to tweak an environment to move
"lz4" out of the way to reproduce the problem, which is what I did to
test this change.
Per discussion with Robert Haas, Tom Lane, Andres Freund and myself.
Discussion: https://postgr.es/m/Ygc51WVAFGocSu4h@paquier.xyz
Commit 6a2a70a02 supposed that any platform having <sys/epoll.h>
would also have <sys/signalfd.h>. It turns out there are still a
few people using platforms where that's not so, so we'd better make
a separate configure probe for it. But since it took this long to
notice, I'm content with the decision to not have a separate code
path for epoll-only machines; we'll just fall back to using poll()
for these stragglers.
Per gripe from Gabriela Serventi. Back-patch to v14 where this
code came in.
Discussion: https://postgr.es/m/CAHOHWE-JjJDfcYuLAAEO7Jk07atFAU47z8TzHzg71gbC0aMy=g@mail.gmail.com
The comment for PGAC_READLINE_VARIABLES says "Readline versions < 2.1
don't have rl_completion_append_character". It seems certain that such
versions are extinct in the wild, though; for sure there are none in the
buildfarm. Libedit has had this variable for at least twenty years too.
Also, tab-complete.c's behavior without it is quite unfriendly, since
we'll emit a space even when completion fails; but we've had no
complaints about that.
Therefore, let's assume this variable is always there, and drop the
configure check to save a few build cycles.
Discussion: https://postgr.es/m/147685.1643858911@sss.pgh.pa.us
With Python 3.10, configure spits out warnings about the module
distutils.sysconfig being deprecated and scheduled for removal in
Python 3.12. Change the uses in configure to use the module sysconfig
instead. The logic stays largely the same, although we have to
rely on INCLUDEPY instead of the deprecated get_python_inc function.
Note that sysconfig exists since Python 2.7, so this moves the minimum
required version up from Python 2.6. Also, sysconfig didn't exist in
Python 3.1, so the minimum 3.x version is now 3.2.
We should consider back-patching this if it gives no further trouble,
as the no-longer-supported versions are old enough to probably not
be interesting to anyone.
Peter Eisentraut, Tom Lane, Andres Freund
Discussion: https://postgr.es/m/c74add3c-09c4-a9dd-1a03-a846e5b2fc52@enterprisedb.com
We're still (see e0e567a106, e0e567a106) working on replacing use of the
deprecated distutils. This commit just makes configure print out the results
of different ways of determining the include path. Hopefully this will help us
to find a way to transition away from distutils without turning the buildfarm
red for prolonged amounts of time.
Discussion: https://postgr.es/m/20220124025301.qu36x44w6m67cnap@alap3.anarazel.de
This avoids possibly selecting Python 2.x on systems that have
both Python 2 and Python 3. We used to feel that what "python"
links to is a user choice that we should honor. However, we're
about to cease support for Python 2, so users will no longer have
any choice of that sort. This small change is being made ahead
of the big Python-2-ectomy so that we can see how much of the
buildfarm is not yet prepared for that. Systems with only
Python 2 will continue to build that way, for now.
Discussion: https://postgr.es/m/2872c9a0-4b0a-1354-d5f6-94d6f85ba354@enterprisedb.com
This reverts commit e0e567a106.
On various platforms, the new approach using the sysconfig module
reported incorrect values for the include directory, and so any
Python-related compilations failed. Revert for now and revisit later.
With Python 3.10, configure spits out warnings about the module
distutils.sysconfig being deprecated and scheduled for removal in
Python 3.12. Change the uses in configure to use the module sysconfig
instead. The logic stays the same.
Note that sysconfig exists since Python 2.7, so this moves the minimum
required version up from Python 2.6.
Discussion: https://www.postgresql.org/message-id/flat/c74add3c-09c4-a9dd-1a03-a846e5b2fc52%40enterprisedb.com
Try to disable ASLR when building in EXEC_BACKEND mode, to avoid random
memory mapping failures while testing. For developer use only, no
effect on regular builds.
Suggested-by: Andres Freund <andres@anarazel.de>
Tested-by: Bossart, Nathan <bossartn@amazon.com>
Discussion: https://postgr.es/m/20210806032944.m4tz7j2w47mant26%40alap3.anarazel.de
1. Update our open() wrapper to check for NT's STATUS_DELETE_PENDING
and translate it to Unix-like errors. This is done with
RtlGetLastNtStatus(), which is dynamically loaded from ntdll. A new
file win32ntdll.c centralizes lookup of NT functions, in case we decide
to add more in the future.
2. Remove non-working code that was trying to do something similar for
stat(), and just reuse the open() wrapper code. As a side effect,
stat() also gains resilience against "sharing violation" errors.
3. Since stat() is used very early in process startup, remove the
requirement that the Win32 signal event has been created before
pgwin32_open_handle() is reached. Instead, teach pg_usleep() to fall
back to a non-interruptible sleep if reached before the signal event is
available.
This could be back-patched, but for now it's in master only. The
problem has apparently been with us for a long time and generated only a
few complaints. Proposed patches trigger it more often, which led to
this investigation and fix.
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Alexander Lakhin <exclusion@gmail.com>
Reviewed-by: Juan José Santamaría Flecha <juanjo.santamaria@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGJz_pZTF9mckn6XgSv69%2BjGwdgLkxZ6b3NWGLBCVjqUZA%40mail.gmail.com
Commit 16f96c74d neglected to consider the possibility of cross-compiling,
causing cross-compiles to fail at the configure stage unless you'd
selected --with-openssl. Since we're now more or less assuming that
/dev/urandom is available everywhere, it seems reasonable to assume
that the cross-compile target has it too, rather than failing.
Per complaint from Vincas Dargis. Back-patch to v14 where this came in.
Discussion: https://postgr.es/m/0dc14a31-acaf-8cae-0df4-a87339b22bd9@gmail.com
Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating
a bunch of platform dependencies as well as fundamentally-obsolete PRNG
code. In addition, this API replacement will ease replacing the
algorithm again in future, should that become necessary.
xoroshiro128** is a few percent slower than the drand48 family,
but it can produce full-width 64-bit random values not only 48-bit,
and it should be much more trustworthy. It's likely to be noticeably
faster than the platform's random(), depending on which platform you
are thinking about; and we can have non-global state vectors easily,
unlike with random(). It is not cryptographically strong, but neither
are the functions it replaces.
Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself
Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
Normally "prove" and "perl" come from the same Perl installation,
but we support the case where they don't (mainly because the MSys
buildfarm animals need this). In that case, AX_PROG_PERL_MODULES
is completely the wrong thing to use, because it's checking what
"perl" has. Instead, make a little TAP test script including the
required modules, and run that under "prove".
We don't need ax_prog_perl_modules.m4 at all after this change,
so remove it.
Back-patch to all supported branches, for the buildfarm's benefit.
(In v10, this also back-patches the effects of commit 264eb03aa.)
Andrew Dunstan and Tom Lane, per an observation by Noah Misch
Discussion: https://postgr.es/m/E1moZHS-0002Cu-Ei@gemulon.postgresql.org
We use "clang" to compile bitcode files for LLVM inlining. That might
be different from the build's main C compiler, so it needs its own set
of compiler flags. To simplify configure, we don't bother adding any
-W switches to that flag set; there's little need since the main build
will show us any warnings. However, if we don't want to see unwanted
warnings, we still have to add any -Wno-warning switches we'd normally
use with clang.
This escaped notice before commit 9ff47ea41, which tried to add
-Wno-compound-token-split-by-macro; buildfarm animals using mismatched
CC and CLANG still showed those warnings. I'm not sure why we never
saw any effects from the lack of -Wno-unused-command-line-argument
(maybe that's only activated by -Wall?). clang does not currently
support -Wno-format-truncation or -Wno-stringop-truncation, although
in the interests of future-proofing and consistency I included tests
for those.
Back-patch to v11 where we started building bitcode files.
Discussion: https://postgr.es/m/2921539.1637254619@sss.pgh.pa.us
Configure tests for the presence of perl modules required for TAP tests,
and that they meet specified minimum version requirements. This patch
makes it report the version of the module that's actually found rather
than just an 'ok' message. This will help in deciding if we can upgrade
minimum requirements for these modules.
Discussion: https://postgr.es/m/f5e1d308-4e33-37a7-bdf1-f6e0c75119de@dunslane.net
clang-12 has introduced -Wcompound-token-split-by-macro, that is causing
a large amount of warnings when building PL/Perl because of its
interactions with upstream Perl. This commit adds one -Wno to CFLAGS at
./configure time if the flag is supported by the compiler to silence all
those warnings.
Upstream perl has fixed this issue, but it is going to take some time
before this is spread across the buildfarm, and we have noticed that
some animals would be useful with an extra -Werror to help with the
detection of incorrect placeholders (see b0cf544), dangomushi being
one.
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/YYr3qYa/R3Gw+Sbg@paquier.xyz
Backpatch-through: 10
This check was used to accommodate a staggering variety in particular
in the type of the third argument of accept(). This is no longer of
concern on currently supported systems. We can just use socklen_t in
the code and put in a simple check that substitutes int for socklen_t
if it's missing, to cover the few stragglers.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/3538f4c4-1886-64f2-dcff-aaad8267fb82@enterprisedb.com
Per the discussion around 3eb1f4d09, let's have configure verify that
the available IPC::Run version is at least 0.79, the agreed-on minimum.
It seems unlikely that this could bite anybody anymore, but it's useful
as documentation. (Based on that, there's little need to back-patch.)
For consistency, also supply a minimum version for the other Perl
module we have an explicit check for, Time::HiRes. I used the
version that ships with Perl 5.8.3.
Discussion: https://postgr.es/m/E1mYY6Z-0006OL-QN@gemulon.postgresql.org
Previously it only checked for version >= 5.8.0, although the
documentation has said that the minimum version is 5.8.3 since
commit dea6ba939. Per the discussion leading up to that commit,
I (tgl) left it that way intentionally because you could, at the
time, do some bare-bones stuff with 5.8.0. But we aren't actually
testing against anything older than 5.8.3, so who knows if that's
still true. It's pretty unlikely that anyone would care anyway,
so let's just make configure's version check match the docs.
Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/87y278s6iq.fsf@wibble.ilmari.org
Discussion: https://postgr.es/m/16894.1501392088@sss.pgh.pa.us
This testing was useful when it was written, nigh twenty years ago,
but it seems fairly pointless for any platform built in the last
dozen or more years. (Compare also the comments at 8a2121185.)
Also we now have reports that the test program itself fails under
ThreadSanitizer. Rather than invest effort in fixing it, let's
just drop it, and assume that the few people who still care
already know they need to use --disable-thread-safety.
Back-patch into v14, for consistency with 8a2121185.
Discussion: https://postgr.es/m/CADhDkKzPSiNvA3Hyq+wSR_icuPmazG0cFe=YnC3U-CFcYLc8Xw@mail.gmail.com
Build farm animals running ancient HPUX and Solaris have a non-standard
sigwait() from draft versions of POSIX, so they didn't like commit
7c09d279. To avoid the problem in general, only try to use sigwait() if
it's declared by <signal.h> and matches the expected declaration. To
select the modern declaration on Solaris (even in non-threaded
programs), move -D_POSIX_PTHREAD_SEMANTICS into the right place to
affect all translation units.
Also fix the error checking. Modern sigwait() doesn't set errno.
Thanks to Tom Lane for help with this.
Discussion: https://postgr.es/m/3187588.1626136248%40sss.pgh.pa.us
Apple's mechanism for dealing with functions that are available
in only some OS versions confuses AC_CHECK_FUNCS, and therefore
AC_REPLACE_FUNCS. We can use AC_CHECK_DECLS instead, so long as
we enable -Werror=unguarded-availability-new. This allows people
compiling for macOS to control whether or not preadv/pwritev are
used by setting MACOSX_DEPLOYMENT_TARGET, rather than supplying
a back-rev SDK. (Of course, the latter still works, too.)
James Hilliard
Discussion: https://postgr.es/m/20210122193230.25295-1-james.hilliard1@gmail.com
Sigh ... I was expecting AC_CHECK_LIB to do something it didn't,
namely update LIBS. This led to not finding ldap_initialize.
Fix by moving the probe for ldap_initialize. In some sense this
is more correct anyway, since (at least for now) we care about
whether ldap_initialize exists in libldap not libldap_r.
Per buildfarm member elver and local testing.
Discussion: https://postgr.es/m/17083-a19190d9591946a7@postgresql.org
I incorrectly diagnosed the reason why hoverfly is unhappy.
Looking closer, it appears that it fails to link libldap
unless libssl is also present; so the problem was my
idea of clearing LIBS before making the check. Revert
to essentially the original coding, except that instead
of failing when libldap_r isn't there, use libldap.
Per buildfarm member hoverfly.
Discussion: https://postgr.es/m/17083-a19190d9591946a7@postgresql.org
In commit d0a02bdb8, I'd supposed that uniformly probing for
ldap_bind would make the intent clearer. However, that seems
not to work on AIX, for obscure reasons (maybe it's a macro
there?). Revert to the former behavior of probing
ldap_simple_bind for thread-safe cases and ldap_bind otherwise.
Per buildfarm member hoverfly.
Discussion: https://postgr.es/m/17083-a19190d9591946a7@postgresql.org
The separate libldap_r is gone and libldap itself is now always
thread-safe. Unfortunately there seems no easy way to tell by
inspection whether libldap is thread-safe, so we have to take
it on faith that libldap is thread-safe if there's no libldap_r.
That should be okay, as it appears that libldap_r was a standard
part of the installation going back at least 20 years.
Report and patch by Adrian Ho. Back-patch to all supported
branches, since people might try to build any of them with
a newer OpenLDAP.
Discussion: https://postgr.es/m/17083-a19190d9591946a7@postgresql.org
Similarly to the cryptohash implementations, this refactors the existing
HMAC code into a single set of APIs that can be plugged with any crypto
libraries PostgreSQL is built with (only OpenSSL currently). If there
is no such libraries, a fallback implementation is available. Those new
APIs are designed similarly to the existing cryptohash layer, so there
is no real new design here, with the same logic around buffer bound
checks and memory handling.
HMAC has a dependency on cryptohashes, so all the cryptohash types
supported by cryptohash{_openssl}.c can be used with HMAC. This
refactoring is an advantage mainly for SCRAM, that included its own
implementation of HMAC with SHA256 without relying on the existing
crypto libraries even if PostgreSQL was built with their support.
This code has been tested on Windows and Linux, with and without
OpenSSL, across all the versions supported on HEAD from 1.1.1 down to
1.0.1. I have also checked that the implementations are working fine
using some sample results, a custom extension of my own, and doing
cross-checks across different major versions with SCRAM with the client
and the backend.
Author: Michael Paquier
Reviewed-by: Bruce Momjian
Discussion: https://postgr.es/m/X9m0nkEJEzIPXjeZ@paquier.xyz
This seems to have been just copied-and-pasted from some other
header checks. But our C code is entirely unprepared to support
such a header name, so it's only wasting cycles to look for it.
If we did need to support it, some #ifdefs would be required.
(A quick trawl at codesearch.debian.net finds some packages that
reference lz4/lz4.h; but they use *only* that spelling, and
appear to be intending to reference their own copy rather than
a system-level installation of liblz4. There's no evidence of
freestanding installations that require this spelling.)
Discussion: https://postgr.es/m/457962.1616362509@sss.pgh.pa.us
It's not okay to just shove the pkg_config results right into our
build flags, for a couple different reasons:
* This fails to maintain the separation between CPPFLAGS and CFLAGS,
as well as that between LDFLAGS and LIBS. (The CPPFLAGS angle is,
I believe, the reason for warning messages reported when building
with MacPorts' liblz4.)
* If pkg_config emits anything other than -I/-D/-L/-l switches,
it's highly unlikely that we want to absorb those. That'd be more
likely to break the build than do anything helpful. (Even the -D
case is questionable; but we're doing that for libxml2, so I kept it.)
Also, it's not okay to skip doing an AC_CHECK_LIB probe, as
evidenced by recent build failure on topminnow; that should
have been caught at configure time.
Model fixes for this on configure's libxml2 support.
It appears that somebody overlooked an autoheader run, too.
Discussion: https://postgr.es/m/20210119190720.GL8560@telsasoft.com
Since commit 2ce439f3 we have opened every file in the data directory
and called fsync() at the start of crash recovery. This can be very
slow if there are many files, leading to field complaints of systems
taking minutes or even hours to begin crash recovery.
Provide an alternative method, for Linux only, where we call syncfs() on
every possibly different filesystem under the data directory. This is
equivalent, but avoids faulting in potentially many inodes from
potentially slow storage.
The new mode comes with some caveats, described in the documentation, so
the default value for the new setting is "fsync", preserving the older
behavior.
Reported-by: Michael Brown <michael.brown@discourse.org>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Paul Guo <guopa@vmware.com>
Reviewed-by: Bruce Momjian <bruce@momjian.us>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: David Steele <david@pgmasters.net>
Discussion: https://postgr.es/m/11bc2bb7-ecb5-3ad0-b39f-df632734cd81%40discourse.org
Discussion: https://postgr.es/m/CAEET0ZHGnbXmi8yF3ywsDZvb3m9CbdsGZgfTXscQ6agcbzcZAw%40mail.gmail.com
There is now a per-column COMPRESSION option which can be set to pglz
(the default, and the only option in up until now) or lz4. Or, if you
like, you can set the new default_toast_compression GUC to lz4, and
then that will be the default for new table columns for which no value
is specified. We don't have lz4 support in the PostgreSQL code, so
to use lz4 compression, PostgreSQL must be built --with-lz4.
In general, TOAST compression means compression of individual column
values, not the whole tuple, and those values can either be compressed
inline within the tuple or compressed and then stored externally in
the TOAST table, so those properties also apply to this feature.
Prior to this commit, a TOAST pointer has two unused bits as part of
the va_extsize field, and a compessed datum has two unused bits as
part of the va_rawsize field. These bits are unused because the length
of a varlena is limited to 1GB; we now use them to indicate the
compression type that was used. This means we only have bit space for
2 more built-in compresison types, but we could work around that
problem, if necessary, by introducing a new vartag_external value for
any further types we end up wanting to add. Hopefully, it won't be
too important to offer a wide selection of algorithms here, since
each one we add not only takes more coding but also adds a build
dependency for every packager. Nevertheless, it seems worth doing
at least this much, because LZ4 gets better compression than PGLZ
with less CPU usage.
It's possible for LZ4-compressed datums to leak into composite type
values stored on disk, just as it is for PGLZ. It's also possible for
LZ4-compressed attributes to be copied into a different table via SQL
commands such as CREATE TABLE AS or INSERT .. SELECT. It would be
expensive to force such values to be decompressed, so PostgreSQL has
never done so. For the same reasons, we also don't force recompression
of already-compressed values even if the target table prefers a
different compression method than was used for the source data. These
architectural decisions are perhaps arguable but revisiting them is
well beyond the scope of what seemed possible to do as part of this
project. However, it's relatively cheap to recompress as part of
VACUUM FULL or CLUSTER, so this commit adjusts those commands to do
so, if the configured compression method of the table happens not to
match what was used for some column value stored therein.
Dilip Kumar. The original patches on which this work was based were
written by Ildus Kurbangaliev, and those were patches were based on
even earlier work by Nikita Glukhov, but the design has since changed
very substantially, since allow a potentially large number of
compression methods that could be added and dropped on a running
system proved too problematic given some of the architectural issues
mentioned above; the choice of which specific compression method to
add first is now different; and a lot of the code has been heavily
refactored. More recently, Justin Przyby helped quite a bit with
testing and reviewing and this version also includes some code
contributions from him. Other design input and review from Tomas
Vondra, Álvaro Herrera, Andres Freund, Oleg Bartunov, Alexander
Korotkov, and me.
Discussion: http://postgr.es/m/20170907194236.4cefce96%40wp.localdomain
Discussion: http://postgr.es/m/CAFiTN-uUpX3ck%3DK0mLEk-G_kUQY%3DSNOTeqdaNRR9FMdQrHKebw%40mail.gmail.com
Don't try to compile src/port/pthread_barrier_wait.c if we opted out of
threads at configure time. Revealed by build farm member gaur, which
can't compile this code because of problems with its pthread
implementation. It shouldn't be trying to, because it's using
--disable-thread-safety.
Defect in commit 44bf3d50.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/2568537.1615603606%40sss.pgh.pa.us
This is a replacement for the existing --with-openssl, extending the
logic to make easier the addition of new SSL libraries. The grammar is
chosen to be similar to --with-uuid, where multiple values can be
chosen, with "openssl" as the only supported value for now.
The original switch, --with-openssl, is kept for compatibility.
Author: Daniel Gustafsson, Michael Paquier
Reviewed-by: Jacob Champion
Discussion: https://postgr.es/m/FAB21FC8-0F62-434F-AA78-6BD9336D630A@yesql.se
With this commit, SHA1 goes through the implementation provided by
OpenSSL via EVP when building the backend with it, and uses as fallback
implementation KAME which was located in pgcrypto and already shaped for
an integration with a set of init, update and final routines.
Structures and routines have been renamed to make things consistent with
the fallback implementations of MD5 and SHA2.
uuid-ossp has used for ages a shortcut with pgcrypto to fetch a copy of
SHA1 if needed. This was built depending on the build options within
./configure, so this cleans up some code and removes the build
dependency between pgcrypto and uuid-ossp.
Note that this will help with the refactoring of HMAC, as pgcrypto
offers the option to use MD5, SHA1 or SHA2, so only the second option
was missing to make that possible.
Author: Michael Paquier
Reviewed-by: Heikki Linnakangas
Discussion: https://postgr.es/m/X9HXKTgrvJvYO7Oh@paquier.xyz
macOS's ranlib issued a warning about an empty pread.o file with the
previous arrangement, on systems new enough to require no replacement
functions. Let's go back to using configure's AC_REPLACE_FUNCS system
to build and include each .o in the library only if it's needed, which
requires moving the *v() functions to their own files.
Also move the _with_retry() wrapper to a more permanent home.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1283127.1610554395%40sss.pgh.pa.us
Provide synchronous vectored file I/O routines. These map to preadv()
and pwritev(), with fallback implementations for systems that don't have
them. Also provide a wrapper pg_pwritev_with_retry() that automatically
retries on short writes.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKGJA%2Bu-220VONeoREBXJ9P3S94Y7J%2BkqCnTYmahvZJwM%3Dg%40mail.gmail.com
Since at least 2001 we've used putenv() and avoided setenv(), on the
grounds that the latter was unportable and not in POSIX. However,
POSIX added it that same year, and by now the situation has reversed:
setenv() is probably more portable than putenv(), since POSIX now
treats the latter as not being a core function. And setenv() has
cleaner semantics too. So, let's reverse that old policy.
This commit adds a simple src/port/ implementation of setenv() for
any stragglers (we have one in the buildfarm, but I'd not be surprised
if that code is never used in the field). More importantly, extend
win32env.c to also support setenv(). Then, replace usages of putenv()
with setenv(), and get rid of some ad-hoc implementations of setenv()
wannabees.
Also, adjust our src/port/ implementation of unsetenv() to follow the
POSIX spec that it returns an error indicator, rather than returning
void as per the ancient BSD convention. I don't feel a need to make
all the call sites check for errors, but the portability stub ought
to match real-world practice.
Discussion: https://postgr.es/m/2065122.1609212051@sss.pgh.pa.us
This module had a dependency on pgcrypto's md5.c that got removed by
b67b57a. Instead of the code from pgcrypto, this code can just use the
new cryptohash routines for MD5 as a drop-in replacement, so let's just
do this switch. This has also the merit to simplify a bit the
compilation of uuid-ossp.
This requires --with-uuid to be reproduced, and I have used e2fs as a
way to reproduce the failure, then test this commit.
Per reports from buildfarm members longfin, florican and sifaka.
Discussion: https://postgr.es/m/X9GToVd3QmWeNvj8@paquier.xyz
Until recently 'native' was implicitly included via 'orcjit', but a change
included in LLVM 11 (not yet released) removed a number of such indirect
component references.
Reported-By: Fabien COELHO <coelho@cri.ensmp.fr>
Reported-By: Andres Freund <andres@anarazel.de>
Reported-By: Thomas Munro <thomas.munro@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20201201064949.mex6kvi2kygby3ni@alap3.anarazel.de
Backpatch: 11-, where jit support was added
Checking for DocBook being installed was valuable when we were on the
OpenSP docs toolchain, because that was rather hard to get installed
fully. Nowadays, as long as you have xmllint and xsltproc installed,
you're good, because those programs will fetch the DocBook files off
the net at need. Moreover, testing this at configure time means that
a network access may well occur whether or not you have any interest
in building the docs later. That can be slow (typically 2 or 3
seconds, though much higher delays have been reported), and it seems
not very nice to be doing an off-machine access without warning, too.
Hence, drop the PGAC_CHECK_DOCBOOK probe, and adjust related
documentation. Without that macro, there's not much left of
config/docbook.m4 at all, so I just removed it.
Back-patch to v11, where we started to use xmllint in the
PGAC_CHECK_DOCBOOK probe.
Discussion: https://postgr.es/m/E2EE6B76-2D96-408A-B961-CAE47D1A86F0@yesql.se
Discussion: https://postgr.es/m/A55A7FC9-FA60-47FE-98B5-139CDC57CE6E@gmail.com
Remove the ability to select random number generator independently from
SSL library. Instead, use the random number generator from the SSL
library (today only OpenSSL supported) if one is configured. If no SSL
library is configured, use the platform default (which means use
CryptoAPI on Win32 and /dev/urandom on Linux).
This also restructures pg_strong_random.c to have three clearly separate
sections, one for each implementation, with two functions in each,
instead of a scattered set of ifdefs throughout the whole file.
Author: Daniel Gustafsson, Magnus Hagander, Michael Paquier
Discussion: https://postgr.es/m/632623.1605460616@sss.pgh.pa.us
We previously put the -isysroot switch only into CPPFLAGS, theorizing
that it was only needed to find the right copies of include files.
However, it seems that we also need to use it while linking programs,
to find the right stub ".tbd" files for libraries. We got away
without that up to now, but apparently that was mostly luck. It may
also be that failures are only observed when the Xcode version is
noticeably out of sync with the host macOS version; the case that's
prompting action right now is that builds fail when using latest Xcode
(12.2) on macOS Catalina, even though it's fine on Big Sur.
Hence, add -isysroot to LDFLAGS as well. (It seems that the more
common practice is to put it in CFLAGS, whence it'd be included at
both compile and link steps. However, we can't mess with CFLAGS in
the platform template file without confusing configure's logic for
choosing default CFLAGS.)
This should be back-patched, but first let's see if the buildfarm
likes it on HEAD.
Report and patch by James Hilliard (some cosmetic mods by me)
Discussion: https://postgr.es/m/20201120003314.20560-1-james.hilliard1@gmail.com
Theoretically one could go into src/test/thread and build/run this
program there. In practice, that hasn't worked since 96bf88d52,
and probably much longer on some platforms (likely including just
the sort of hoary leftovers where this test might be of interest).
While it wouldn't be too hard to repair the breakage, the fact that
nobody has noticed for two years shows that there is zero usefulness
in maintaining this build pathway. Let's get rid of it and decree
that thread_test.c is *only* meant to be built/used in configure.
Given that decision, it makes sense to put thread_test.c under config/
and get rid of src/test/thread altogether, so that's what I did.
In passing, update src/test/README, which had been ignored by some
not-so-recent additions of subdirectories.
Discussion: https://postgr.es/m/227659.1603041612@sss.pgh.pa.us
Hack things so that our idea of "struct stat" is equivalent to Windows'
struct __stat64, allowing it to have a wide enough st_size field.
Instead of relying on native stat(), use GetFileInformationByHandle().
This avoids a number of issues with Microsoft's multiple and rather
slipshod emulations of stat(). We still need to jump through hoops
to deal with ERROR_DELETE_PENDING, though :-(
Pull the relevant support code out of dirmod.c and put it into
its own file, win32stat.c.
Still TODO: do we need to do something different with lstat(),
rather than treating it identically to stat()?
Juan José Santamaría Flecha, reviewed by Emil Iggland;
based on prior work by Michael Paquier, Sergey Zubkovsky, and others
Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905CF5099@g01jpexmbkw24
Discussion: https://postgr.es/m/15858-9572469fd3b73263@postgresql.org
Replace CFLAGS_VECTOR with CFLAGS_UNROLL_LOOPS and CFLAGS_VECTORIZE,
allowing us to distinguish whether we want to apply -funroll-loops,
-ftree-vectorize, or both to a particular source file. Up to now
the only consumer of the symbol has been checksum.c which wants
both, so that there was no need to distinguish; but that's about
to change.
Amit Khandekar, reviewed and edited a little by me
Discussion: https://postgr.es/m/CAJ3gD9evtA_vBo+WMYMyT-u=keHX7-r8p2w7OSRfXf42LTwCZQ@mail.gmail.com
Three groups of issues needed to be addressed:
load_external_function() and related functions returned PGFunction,
even though not necessarily all callers are looking for a function of
type PGFunction. Since these functions are really just wrappers
around dlsym(), change to return void * just like dlsym().
In dynahash.c, we are using strlcpy() where a function with a
signature like memcpy() is expected. This should be safe, as the new
comment there explains, but the cast needs to be augmented to avoid
the warning.
In PL/Python, methods all need to be cast to PyCFunction, per Python
API, but this now runs afoul of these warnings. (This issue also
exists in core CPython.)
To fix the second and third case, we add a new type pg_funcptr_t that
is defined specifically so that gcc accepts it as a special function
pointer that can be cast to any other function pointer without the
warning.
Also add -Wcast-function-type to the standard warning flags, subject
to configure check.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/1e97628e-6447-b4fd-e230-d109cec2d584%402ndquadrant.com
The additional pain from level 4 is excessive for the gain.
Also revert all the source annotation changes to their original
wordings, to avoid back-patching pain.
Discussion: https://postgr.es/m/31166.1589378554@sss.pgh.pa.us
Use it at level 4, a bit more restrictive than the default level, and
tweak our commanding comments to FALLTHROUGH.
(However, leave zic.c alone, since it's external code; to avoid the
warnings that would appear there, change CFLAGS for that file in the
Makefile.)
Author: Julien Rouhaud <rjuju123@gmail.com>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/20200412081825.qyo5vwwco3fv4gdo@nol
Discussion: https://postgr.es/m/flat/E1fDenm-0000C8-IJ@gemulon.postgresql.org
As of Windows 10 version 1803, Unix-domain sockets are supported on
Windows. But it's not automatically detected by configure because it
looks for struct sockaddr_un and Windows doesn't define that. So we
just make our own definition on Windows and override the configure
result.
Set DEFAULT_PGSOCKET_DIR to empty on Windows so by default no
Unix-domain socket is used, because there is no good standard
location.
In pg_upgrade, we have to do some extra tweaking to preserve the
existing behavior of not using Unix-domain sockets on Windows. Adding
support would be desirable, but it needs further work, in particular a
way to select whether to use Unix-domain sockets from the command-line
or with a run-time test.
The pg_upgrade test script needs a fix. The previous code passed
"localhost" to postgres -k, which only happened to work because
Windows used to ignore the -k argument value altogether. We instead
need to pass an empty string to get the desired effect.
The test suites will continue to not use Unix-domain sockets on
Windows. This requires a small tweak in pg_regress.c. The TAP tests
don't need to be changed because they decide by the operating system
rather than HAVE_UNIX_SOCKETS.
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/54bde68c-d134-4eb8-5bd3-8af33b72a010@2ndquadrant.com
It was for unclear reasons defined in a separate location, which makes
it more cumbersome to override for testing, and it also did not have
any prominent documentation. Move to pg_config_manual.h, where
similar things are already collected.
The previous definition on the command-line had the effect of defining
it to the value 1, but now that we don't need that anymore we just
define it to empty, to simplify manual editing a bit.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/b7053ba8-b008-5335-31de-2fe4fe41ef0f%402ndquadrant.com
If pkg-config is installed and knows about libxml2, use its information
rather than asking xml2-config. Otherwise proceed as before. This
patch allows "configure --with-libxml" to succeed on platforms that
have pkg-config but not xml2-config, which is likely to soon become
a typical situation.
The old mechanism can be forced by setting XML2_CONFIG explicitly
(hence, build processes that were already doing so will certainly
not need adjustment). Also, it's now possible to set XML2_CFLAGS
and XML2_LIBS explicitly to override both programs.
There is a small risk of this breaking existing build processes,
if there are multiple libxml2 installations on the machine and
pkg-config disagrees with xml2-config about which to use. The
only case where that seems really likely is if a builder has tried
to select a non-default xml2-config by putting it early in his PATH
rather than setting XML2_CONFIG. Plan to warn against that in the
minor release notes.
Back-patch to v10; before that we had no pkg-config infrastructure,
and it doesn't seem worth adding it for this.
Hugh McMaster and Tom Lane; Peter Eisentraut also made an earlier
attempt at this, from which I lifted most of the docs changes.
Discussion: https://postgr.es/m/CAN9BcdvfUwc9Yx5015bLH2TOiQ-M+t_NADBSPhMF7dZ=pLa_iw@mail.gmail.com
This removes another relic from the old nmake-based Windows build.
version_stamp.pl put version number information into win32ver.rc. But
win32ver.rc already gets other version number information from the
preprocessor at build time, so it would make more sense if all version
number information would be handled in the same way and we don't have
two places that do it.
What we need for this is having the major version number and the minor
version number as separate integer symbols. Both configure and
Solution.pm already have that logic, because they compute
PG_VERSION_NUM. So we just keep all the logic there now. Put the
minor version number into a new symbol PG_MINORVERSION_NUM. Also, add
a symbol PG_MAJORVERSION_NUM, which is a number, alongside the
existing PG_MAJORVERSION, which is a string.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/1ee46ac4-a9b2-4531-bf54-5ec2e374634d@2ndquadrant.com
These compiler features are required by C99, so remove the configure
probes for them.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
Windows has this, and so do all other live platforms according to the
buildfarm; it's been required by POSIX since SUSv2. So remove the
configure probe and tests of HAVE_WCHAR_H.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
These are required by POSIX since SUSv2, and no live platforms fail
to provide them. On Windows, utime() exists and we bring our own
<utime.h>, so we're good there too. So remove the configure probes
and ad-hoc substitute code. We don't need to check for utimes()
anymore either, since that was only used as a substitute.
In passing, make the Windows build include <sys/utime.h> only where
we need it, not everywhere.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
Windows has this since _MSC_VER >= 1200, and so do all other live
platforms according to the buildfarm, so remove the configure probe
and src/port/ substitution.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
Windows has this, and so do all other live platforms according to the
buildfarm, so remove the configure probe and c.h's substitute code.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
Windows has this, and so do all other live platforms according to the
buildfarm, so remove the configure probe and float.c's substitute code.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
Windows has this, and so do all other live platforms according to the
buildfarm, so remove the configure probe and src/port/ substitution.
This also lets us get rid of some configure probes that existed only
to support src/port/isinf.c. I kept the port.h hack to force using
__builtin_isinf() on clang, though.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
Windows has this, and so do all other live platforms according to the
buildfarm, so remove the configure probe and src/port/ substitution.
Keep the probe that detects whether _LARGEFILE_SOURCE has to be
defined to get that, though ... that seems to be still relevant in
some places.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
stdint.h belongs to the compiler (as opposed to inttypes.h), so by
requiring a C99 compiler we can also require stdint.h
unconditionally. Remove configure checks and other workarounds for
it.
This also removes a few steps in the required portability adjustments
to the imported time zone code, which can be applied on the next
import.
When using GCC on a platform that is otherwise pre-C99, this will now
require at least GCC 4.5, which is the first release that supplied a
standard-conforming stdint.h if the native platform didn't have it.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/5d398bbb-262a-5fed-d839-d0e5cff3c0d7%402ndquadrant.com
The previous system had configure put the value into the makefiles and
then have the makefiles pass them to the build of pg_config. That was
put in place when pg_config was a shell script. We can simplify that
by having configure put the value into pg_config.h directly. This
also makes the standard build system match how the MSVC build system
already does it.
Discussion: https://www.postgresql.org/message-id/flat/6e457870-cef5-5f1d-b57c-fc89cfb8a788%402ndquadrant.com
Use kevent(2) to wait for events on the BSD family of operating
systems and macOS. This is similar to the epoll(2) support added
for Linux by commit 98a64d0bd.
Author: Thomas Munro
Reviewed-by: Andres Freund, Marko Tiikkaja, Tom Lane
Tested-by: Mateusz Guzik, Matteo Beccati, Keith Fiske, Heikki Linnakangas, Michael Paquier, Peter Eisentraut, Rui DeSousa, Tom Lane, Mark Wong
Discussion: https://postgr.es/m/CAEepm%3D37oF84-iXDTQ9MrGjENwVGds%2B5zTr38ca73kWR7ez_tA%40mail.gmail.com
I had supposed that all versions of Readline that have filename
quoting hooks also have the rl_completion_suppress_quote variable.
But it seems OpenBSD managed to find a version someplace that does
not, so we'll have to expend a separate configure probe for that.
(Light testing suggests that this version also lacks the bugs that
make it necessary to frob that variable. Hooray!)
Per buildfarm.
The Readline library contains a fair amount of knowledge about how to
tab-complete filenames, but it turns out that that doesn't work too well
unless we follow its expectation that we use its filename quoting hooks
to quote and de-quote filenames. We were trying to do such quote handling
within complete_from_files(), and that's still what we have to do if we're
using libedit, which lacks those hooks. But for Readline, it works a lot
better if we tell Readline that single-quote is a quoting character and
then provide hooks that know the details of the quoting rules for SQL
and psql meta-commands.
Hence, resurrect the quoting hook functions that existed in the original
version of tab-complete.c (and were disabled by commit f6689a328 because
they "didn't work so well yet"), and whack on them until they do seem to
work well.
Notably, this fixes bug #16059 from Steven Winfield, who pointed out
that the previous coding would strip quote marks from filenames in SQL
COPY commands, even though they're syntactically necessary there.
Now, we not only don't do that, but we'll add a quote mark when you
tab-complete, even if you didn't type one.
Getting this to work across a range of libedit versions (and, to a
lesser extent, libreadline versions) was depressingly difficult.
It will be interesting to see whether the new regression test cases
pass everywhere in the buildfarm.
Some future patch might try to handle quoted SQL identifiers with
similar explicit quoting/dequoting logic, but that's for another day.
Patch by me, reviewed by Peter Eisentraut.
Discussion: https://postgr.es/m/16059-8836946734c02b84@postgresql.org
Supporting very old Python versions is a maintenance burden,
especially with the several variant test files to maintain for Python
<2.6.
Since we have dropped support for older OpenSSL versions in
7b283d0e1d, RHEL 5 is now effectively
desupported, and that was also the only mainstream operating system
still using Python versions before 2.6, so it's a good time to drop
those as well.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/98b69261-298c-13d2-f34d-836fd9c29b21%402ndquadrant.com
Up to now, psql's tab-complete.c has had exactly no regression test
coverage. This patch is an experimental attempt to add some.
This needs Perl's IO::Pty module, which isn't installed everywhere,
so the test script just skips all tests if that's not present.
There may be other portability gotchas too, so I await buildfarm
results with interest.
So far this just covers a few very basic keyword-completion and
query-driven-completion scenarios, which should be enough to let us
get a feel for whether this is practical at all from a portability
standpoint. If it is, there's lots more that can be done.
Discussion: https://postgr.es/m/10967.1577562752@sss.pgh.pa.us
The getpeereid() uses have so far been protected by HAVE_UNIX_SOCKETS,
so they didn't ever care about Windows support. But in anticipation
of Unix-domain socket support on Windows, that needs to be handled
differently.
Windows doesn't support getpeereid() at this time, so we use the
existing not-supported code path. We let configure do its usual thing
of picking up the replacement from libpgport, instead of the custom
overrides that it was doing before.
But then Windows doesn't have struct passwd, so this patch sprinkles
some additional #ifdef WIN32 around to make it work. This is similar
to existing code that deals with this issue.
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/5974caea-1267-7708-40f2-6009a9d653b0@2ndquadrant.com
This function is supported down to OpenSSL 0.9.8, which is the oldest
version supported since 593d4e4 (from Postgres 10 onwards), and is used
since e3bdb2d (from 11 onwards). It is defined as a macro from OpenSSL
0.9.8 to 1.0.2, and as a function in 1.1.0 and newer versions. However,
the configure check present is only adapted for functions. So, even if
the code would be able to compile, configure fails to detect the macro,
causing it to be ignored when compiling the code with OpenSSL from 0.9.8
to 1.0.2.
The code needs a configure check as per a364dfa, which has fixed a
compilation issue with a past version of LibreSSL in NetBSD 5.1. On
HEAD, just remove the configure check as the last release of NetBSD 5 is
from 2014 (and we have no more buildfarm members for it). In 11 and 12,
improve the configure logic so as both macros and functions are
correctly detected. This makes NetBSD 5 still work on already-released
branches, but not for 13 onwards.
The patch for HEAD is from me, and Daniel has written the version to use
for the back-branches.
Author: Michael Paquier, Daniel Gustaffson
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20191205083252.GE5064@paquier.xyz
Discussion: https://postgr.es/m/98F7F99E-1129-41D8-B86B-FE3B1E286881@yesql.se
Backpatch-through: 11
This build option was once useful to maintain compatibility with
version-0 functions, but those are no longer supported, so this option
is no longer useful for end users. We keep the option available to
developers in pg_config_manual.h so that it is easy to test the
pass-by-reference code paths without having to fire up a 32-bit
machine.
Discussion: https://www.postgresql.org/message-id/flat/f3e1e576-2749-bbd7-2d57-3f9dcf75255a@2ndquadrant.com
This completes the task begun in commit 1408d5d86, to synchronize
ECPG's exported definitions with the definition of bool used by
c.h (and, therefore, the one actually in use in the ECPG library).
On practically all modern platforms, ecpglib.h will now just
include <stdbool.h>, which should surprise nobody anymore.
That removes a header-inclusion-order hazard for ECPG clients,
who previously might get build failures or unexpected behavior
depending on whether they'd included <stdbool.h> themselves,
and if so, whether before or after ecpglib.h.
On platforms where sizeof(_Bool) is not 1 (only old PPC-based
Mac systems, as far as I know), things are still messy, as
inclusion of <stdbool.h> could still break ECPG client code.
There doesn't seem to be any clean fix for that, and given the
probably-negligible population of users who would care anymore,
it's not clear we should go far out of our way to cope with it.
This change at least fixes some header-inclusion-order hazards
for our own code, since c.h and ecpglib.h previously disagreed
on whether bool should be char or unsigned char.
To implement this with minimal invasion of ECPG client namespace,
move the choice of whether to rely on <stdbool.h> into configure,
and have it export a configuration symbol PG_USE_STDBOOL.
ecpglib.h no longer exports definitions for TRUE and FALSE,
only their lowercase brethren. We could undo that if we get
push-back about it.
Ideally we'd back-patch this as far as v11, which is where c.h
started to rely on <stdbool.h>. But the odds of creating problems
for formerly-working ECPG client code seem about as large as the
odds of fixing any non-working cases, so we'll just do this in HEAD.
Discussion: https://postgr.es/m/CAA4eK1LmaKO7Du9M9Lo=kxGU8sB6aL8fa3sF6z6d5yYYVe3BuQ@mail.gmail.com
Add some support for automatically showing backtraces in certain error
situations in the server. Backtraces are shown on assertion failure;
also, a new setting backtrace_functions can be set to a list of C
function names, and all ereport()s and elog()s from the mentioned
functions will have backtraces generated. Finally, the function
errbacktrace() can be manually added to an ereport() call to generate a
backtrace for that call.
Authors: Peter Eisentraut, Álvaro Herrera
Discussion: https://postgr.es/m//5f48cb47-bf1e-05b6-7aae-3bf2cd01586d@2ndquadrant.com
Discussion: https://postgr.es/m/CAMsr+YGL+yfWE=JvbUbnpWtrRZNey7hJ07+zT4bYJdVp4Szdrg@mail.gmail.com
On recent Red Hat platforms (at least RHEL 8 and Fedora 30, maybe older),
configure's probe for libperl failed if the user forces CFLAGS to be -O0.
This is because some code in perl's inline.h fails to be optimized away
at -O0, and said code doesn't work if compiled without -fPIC.
To fix, add CFLAGS_SL to the compile flags used during the libperl probe.
This is a better simulation of the way that plperl is built, anyway,
so it might forestall other issues in future.
Per gripe from Kyotaro Horiguchi. Back-patch to all supported branches,
since people might want to build older branches on these platforms.
Discussion: https://postgr.es/m/20191010.144533.263180400.horikyota.ntt@gmail.com
Move the platform-dependent logic that sets CFLAGS_SL from
src/makefiles/Makefile.foo to src/template/foo, so that the value
is determined at configure time and thus is available while running
configure's tests.
On a couple of platforms this might save a few microseconds of build
time by eliminating a test that make otherwise has to do over and over.
Otherwise it's pretty much a wash for build purposes; in particular,
this makes no difference to anyone who might be overriding CFLAGS_SL
via a make option.
This patch in itself does nothing with the value and thus should not
change any behavior, though you'll probably have to re-run configure
to get a correctly updated Makefile.global. We'll use the new
configure variable in a follow-on patch.
Per gripe from Kyotaro Horiguchi. Back-patch to all supported branches,
because the follow-on patch is a portability bug fix.
Discussion: https://postgr.es/m/20191010.144533.263180400.horikyota.ntt@gmail.com
This reverts commit e7ff59686e. It
defined pg_atomic_fetch_add_u32_impl() without defining
pg_atomic_compare_exchange_u32_impl(), which is incompatible with
src/include/port/atomics/fallback.h. Per buildfarm member prairiedog.
Discussion: https://postgr.es/m/7517.1568470247@sss.pgh.pa.us
Use the explicit_bzero() function in places where it is important that
security information such as passwords is cleared from memory. There
might be other places where it could be useful; this is just an
initial collection.
For platforms that don't have explicit_bzero(), provide various
fallback implementations. (explicit_bzero() itself isn't standard,
but as Linux/glibc, FreeBSD, and OpenBSD have it, it's the most common
spelling, so it makes sense to make that the invocation point.)
Discussion: https://www.postgresql.org/message-id/flat/42d26bde-5d5b-c90d-87ae-6cab875f73be%402ndquadrant.com
fe0a0b5 has removed the last use of this routine from pgcrypto, leading
to a useless symbol definition and an extra configure check.
Author: Michael Paquier
Reviewed-by: Daniel Gustafsson, Tom Lane
Discussion: https://postgr.es/m/20190626142544.GN1714@paquier.xyz
Currently only frogmouth in the buildfarm uses the 32bit params, and
it's not able to build past release 10, so put those last, saving
substantial configure time on more modern systems. Even if we get a
modern 32 bit Windows system at some stage we should probably prefer the
64 bit interface here these days.
Test for the compiler builtins __builtin_clz, __builtin_ctz, and
__builtin_popcount, and make use of these in preference to
handwritten C code if they're available. Create src/port
infrastructure for "leftmost one", "rightmost one", and "popcount"
so as to centralize these decisions.
On x86_64, __builtin_popcount generally won't make use of the POPCNT
opcode because that's not universally supported yet. Provide code
that checks CPUID and then calls POPCNT via asm() if available.
This requires indirecting through a function pointer, which is
an annoying amount of overhead for a one-instruction operation,
but it's probably not worth working harder than this for our
current use-cases.
I'm not sure we've found all the existing places that could profit
from this new infrastructure; but we at least touched all the
ones that used copied-and-pasted versions of the bitmapset.c code,
and got rid of multiple copies of the associated constant arrays.
While at it, replace c-compiler.m4's one-per-builtin-function
macros with a single one that can handle all the cases we need
to worry about so far. Also, because I'm paranoid, make those
checks into AC_LINK checks rather than just AC_COMPILE; the
former coding failed to verify that libgcc has support for the
builtin, in cases where it's not inline code.
David Rowley, Thomas Munro, Alvaro Herrera, Tom Lane
Discussion: https://postgr.es/m/CAKJS1f9WTAGG1tPeJnD18hiQW5gAk59fQ6WK-vfdAKEHyRg2RA@mail.gmail.com
Deal with silent-underflow errors in float4 for cygwin and mingw by
using our strtof() wrapper; deal with misrounding errors by adding
them to the resultmap. Some slight reorganization of declarations was
done to avoid duplicating material between cygwin.h and win32_port.h.
While here, remove from the resultmap all references to
float8-small-is-zero; inspection of cygwin output suggests it's no
longer required there, and the freebsd/netbsd/openbsd entries should
no longer be necessary (these date back to c. 2000). This commit
doesn't remove the file itself nor the documentation references for
it; that will happen in a subsequent commit if all goes well.
This reverts commits fc6c72747a, 109de05cbb, d0b4663c23 and
711bab1e4d.
Somebody will have to try harder before submitting this patch again.
I've spent entirely too much time on it already, and the #ifdef maze yet
to be written in order for it to build at all got on my nerves. The
amount of work needed to get a platform-specific performance improvement
that's barely above the noise level is not worth it.
Split out these new functions in three parts: one in a new file that
uses the compiler builtin and gets compiled with the -mpopcnt compiler
option if it exists; another one that uses the compiler builtin but not
the compiler option; and finally the fallback with open-coded
algorithms.
Split out the configure logic: in the original commit, it was selecting
to use the -mpopcnt compiler switch together with deciding whether to
use the compiler builtin, but those two things are really separate.
Split them out. Also, expose whether the builtin exists to
Makefile.global, so that src/port's Makefile can decide whether to
compile the hw-optimized file.
Remove CPUID test for CTZ/CLZ. Make pg_{right,left}most_ones use either
the compiler intrinsic or open-coded algo; trying to use the
HW-optimized version is a waste of time. Make them static inline
functions.
Discussion: https://postgr.es/m/20190213221719.GA15976@alvherre.pgsql
We were using uint64 function arguments as "long int" arguments to
compiler builtins, which fails on machines where long ints are 32 bits:
the upper half of the uint64 was being ignored. Fix by using the "ll"
builtin variants instead, which on those machines take 64 bit arguments.
Also, remove configure tests for __builtin_popcountl() (as well as
"long" variants for ctz and clz): the theory here is that any compiler
version will provide all widths or none, so one test suffices. Were
this theory to be wrong, we'd have to add tests for
__builtin_popcountll() and friends, which would be tedious.
Per failures in buildfarm member lapwing and ensuing discussion.
These opcodes have been around in the AMD world since 2007, and 2008 in
the case of intel. They're supported in GCC and Clang via some __builtin
macros. The opcodes may be unavailable during runtime, in which case we
fall back on a C-based implementation of the code. In order to get the
POPCNT instruction we must pass the -mpopcnt option to the compiler. We
do this only for the pg_bitutils.c file.
David Rowley (with fragments taken from a patch by Thomas Munro)
Discussion: https://postgr.es/m/CAKJS1f9WTAGG1tPeJnD18hiQW5gAk59fQ6WK-vfdAKEHyRg2RA@mail.gmail.com
Previously, floating-point output was done by rounding to a specific
decimal precision; by default, to 6 or 15 decimal digits (losing
information) or as requested using extra_float_digits. Drivers that
wanted exact float values, and applications like pg_dump that must
preserve values exactly, set extra_float_digits=3 (or sometimes 2 for
historical reasons, though this isn't enough for float4).
Unfortunately, decimal rounded output is slow enough to become a
noticable bottleneck when dealing with large result sets or COPY of
large tables when many floating-point values are involved.
Floating-point output can be done much faster when the output is not
rounded to a specific decimal length, but rather is chosen as the
shortest decimal representation that is closer to the original float
value than to any other value representable in the same precision. The
recently published Ryu algorithm by Ulf Adams is both relatively
simple and remarkably fast.
Accordingly, change float4out/float8out to output shortest decimal
representations if extra_float_digits is greater than 0, and make that
the new default. Applications that need rounded output can set
extra_float_digits back to 0 or below, and take the resulting
performance hit.
We make one concession to portability for systems with buggy
floating-point input: we do not output decimal values that fall
exactly halfway between adjacent representable binary values (which
would rely on the reader doing round-to-nearest-even correctly). This
is known to be a problem at least for VS2013 on Windows.
Our version of the Ryu code originates from
https://github.com/ulfjack/ryu/ at commit c9c3fb1979, but with the
following (significant) modifications:
- Output format is changed to use fixed-point notation for small
exponents, as printf would, and also to use lowercase 'e', a
minimum of 2 exponent digits, and a mandatory sign on the exponent,
to keep the formatting as close as possible to previous output.
- The output of exact midpoint values is disabled as noted above.
- The integer fast-path code is changed somewhat (since we have
fixed-point output and the upstream did not).
- Our project style has been largely applied to the code with the
exception of C99 declaration-after-statement, which has been
retained as an exception to our present policy.
- Most of upstream's debugging and conditionals are removed, and we
use our own configure tests to determine things like uint128
availability.
Changing the float output format obviously affects a number of
regression tests. This patch uses an explicit setting of
extra_float_digits=0 for test output that is not expected to be
exactly reproducible (e.g. due to numerical instability or differing
algorithms for transcendental functions).
Conversions from floats to numeric are unchanged by this patch. These
may appear in index expressions and it is not yet clear whether any
change should be made, so that can be left for another day.
This patch assumes that the only supported floating point format is
now IEEE format, and the documentation is updated to reflect that.
Code by me, adapting the work of Ulf Adams and other contributors.
References:
https://dl.acm.org/citation.cfm?id=3192369
Reviewed-by: Tom Lane, Andres Freund, Donald Dong
Discussion: https://postgr.es/m/87r2el1bx6.fsf@news-spur.riddles.org.uk
Using strtod() creates a double-rounding problem; the input decimal
value is first rounded to the nearest double; rounding that to the
nearest float may then give an incorrect result.
An example is that 7.038531e-26 when input via strtod and then rounded
to float4 gives 0xAE43FEp-107 instead of the correct 0xAE43FDp-107.
Values output by earlier PG versions with extra_float_digits=3 should
all be read in with the same values as previously. However, values
supplied by other software using shortest representations could be
mis-read.
On platforms that lack a strtof() entirely, we fall back to the old
incorrect rounding behavior. (As strtof() is required by C99, such
platforms are considered of primarily historical interest.) On VS2013,
some workarounds are used to get correct error handling.
The regression tests now test for the correct input values, so
platforms that lack strtof() will need resultmap entries. An entry for
HP-UX 10 is included (more may be needed).
Reviewed-By: Tom Lane
Discussion: https://postgr.es/m/871s5emitx.fsf@news-spur.riddles.org.uk
Discussion: https://postgr.es/m/87d0owlqpv.fsf@news-spur.riddles.org.uk
The comment marker "#" is copied to the output, so it's only
appropriate for comments that make sense in the shell output. For
comments about the Autoconf language, "dnl" should be used.
While Windows (allegedly) has _configthreadlocale() pretty far back,
it seems MinGW didn't acquire support for that till more recently.
Fortunately, we can use an autoconf probe on that toolchain,
instead of guessing whether it's there. (Hm, I wonder whether Cygwin
will need this also.)
Per buildfarm.
Discussion: https://postgr.es/m/20190121193512.tdmcnic2yjxlufaw@alap3.anarazel.de
ecpglib attempts to force the LC_NUMERIC locale to "C" while reading
server output, to avoid problems with strtod() and related functions.
Historically it's just issued setlocale() calls to do that, but that
has major problems if we're in a threaded application. setlocale()
itself is not required by POSIX to be thread-safe (and indeed is not,
on recent OpenBSD). Moreover, its effects are process-wide, so that
we could cause unexpected results in other threads, or another thread
could change our setting.
On platforms having uselocale(), which is required by POSIX:2008,
we can avoid these problems by using uselocale() instead. Windows
goes its own way as usual, but we can make it safe by using
_configthreadlocale(). Platforms having neither continue to use the
old code, but that should be pretty much nobody among current systems.
This should get back-patched, but let's see what the buildfarm
thinks of it first.
Michael Meskes and Tom Lane; thanks also to Takayuki Tsunakawa.
Discussion: https://postgr.es/m/31420.1547783697@sss.pgh.pa.us
Commit c0d0e54084 replaced the ones in the documentation, but missed out
on the ones in the code. Replace those as well, but unlike c0d0e54084,
don't backpatch the code changes to avoid breaking translations.
Recent OpenBSD (at least 5.9 and up) has a version of getopt(3)
that will not cope with the "-:" spec we use to accept double-dash
options in postgres.c and postmaster.c. Admittedly, that's a hack
because POSIX only requires getopt() to allow alphanumeric option
characters. I have no desire to find another way, however, so
let's just do what we were already doing on Solaris: force use
of our own src/port/getopt.c implementation.
In passing, improve some of the comments around said implementation.
Per buildfarm and local testing. Back-patch to all supported branches.
Discussion: https://postgr.es/m/30197.1547835700@sss.pgh.pa.us
AC_ARG_VAR is necessary if an environment variable influences a
configure result that is then used by other tests that are cached.
With AC_ARG_VAR, a change in the variable is detected on subsequent
configure runs and the user is then advised to remove the cache.
This adds AC_ARG_VAR calls for: MSGFMT, PERL, PYTHON, TCLSH, XML2_CONFIG
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/30672.1546816567@sss.pgh.pa.us
This removes a portion of infrastructure introduced by fe0a0b5 to allow
compilation of Postgres in environments where no strong random source is
available, meaning that there is no linking to OpenSSL and no
/dev/urandom (Windows having its own CryptoAPI). No systems shipped
this century lack /dev/urandom, and the buildfarm is actually not
testing this switch at all, so just remove it. This simplifies
particularly some backend code which included a fallback implementation
using shared memory, and removes a set of alternate regression output
files from pgcrypto.
Author: Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20181230063219.GG608@paquier.xyz
It appears that all platforms that have sys_siglist[] also have
strsignal(), making that fallback case in pg_strsignal() dead code.
Getting rid of it allows dropping a configure test, which seems worth
more than providing textual signal descriptions on whatever platforms
might still hypothetically have use for the fallback case.
Discussion: https://postgr.es/m/25758.1544983503@sss.pgh.pa.us
At least as far back as the 2008 spec, POSIX has defined strsignal(3)
for looking up descriptive strings for signal numbers. We hadn't gotten
the word though, and were still using the crufty old sys_siglist array,
which is in no standard even though most Unixen provide it.
Aside from not being formally standards-compliant, this was just plain
ugly because it involved #ifdef's at every place using the code.
To eliminate the #ifdef's, create a portability function pg_strsignal,
which wraps strsignal(3) if available and otherwise falls back to
sys_siglist[] if available. The set of Unixen with neither API is
probably empty these days, but on any platform with neither, you'll
just get "unrecognized signal". All extant callers print the numeric
signal number too, so no need to work harder than that.
Along the way, upgrade pg_basebackup's child-error-exit reporting
to match the rest of the system.
Discussion: https://postgr.es/m/25758.1544983503@sss.pgh.pa.us
This change doesn't fix any bugs that we've heard about, but it seems
like a good idea on general principles to track upstream occasionally.
Discussion: https://postgr.es/m/3320.1542647565@sss.pgh.pa.us
Calling AC_CHECK_DECLS before we've finished setting up the compiler's
CFLAGS seems like a pretty risky proposition, especially now that the
first use of that macro will result in a test to see whether the compiler
gives warning or error for undeclared built-in functions. That answer
could very easily get changed later than where PGAC_LLVM_SUPPORT is
called; furthermore, it's hardly unlikely that flags such as -D_GNU_SOURCE
could change visibility of declarations. Hence, be a little less cavalier
about where to do LLVM-related tests. This results in v11 and HEAD doing
the warning-or-error check at the same place in the script as older
branches are doing it, which seems like a good thing.
Per further thought about commits 0b59b0e8b and 16fbac39f.
The test case that Autoconf uses to discover whether a function has
been declared doesn't work reliably with clang, because clang reports
a warning not an error if the name is a known built-in function.
On some platforms, this results in a lot of compile-time warnings about
strlcpy and related functions not having been declared.
There is a fix for this (by Noah Misch) in the upstream Autoconf sources,
but since they've not made a release in years and show no indication of
doing so anytime soon, let's just absorb their fix directly. We can
revert this when and if we update to a newer Autoconf release.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/26819.1542515567@sss.pgh.pa.us
Any Autoconf macro that uses AC_REQUIRES -- directly or indirectly --
must not be inside a plain shell "if" test; if it is, whatever code
gets pulled in by the AC_REQUIRES will also be inside that "if".
Instead of "if" we can use AS_IF, which knows how to get this right
(cf commit 01051a987).
The only immediate problem from getting this wrong was that AC_PROG_AWK
had to be run twice, once inside the "if llvm" block and once in the
main line. However, it broke a different patch I'm about to submit
more thoroughly.