Redefine our exact width types with standard C99 types and macros,
including int64_t, INT64_MAX, INT64_C(), PRId64 etc. We were already
using <stdint.h> types in a few places.
One complication is that Windows' <inttypes.h> uses format strings like
"%I64d", "%I32", "%I" for PRI*64, PRI*32, PTR*PTR, instead of mapping to
other standardized format strings like "%lld" etc as seen on other known
systems. Teach our snprintf.c to understand them.
This removes a lot of configure clutter, and should also allow 64-bit
numbers and other standard types to be used in localized messages
without casting.
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/ME3P282MB3166F9D1F71F787929C0C7E7B6312%40ME3P282MB3166.AUSP282.PROD.OUTLOOK.COM
The C standard says that sizeof(bool) is implementation-defined, but we
know of no current systems where it is not 1. The last known systems
seem to have been Apple macOS/PowerPC 10.5 and Microsoft Visual C++ 4,
both long defunct.
PostgreSQL has always required sizeof(bool) == 1 for the definition of
bool that it used, but previously it would define its own type if the
system-provided bool had a different size. That was liable to cause
memory layout problems when interacting with system and third-party
libraries on (by now hypothetical) computers with wider _Bool, and now
C23 has introduced a new problem by making bool a built-in datatype
(like C++), so the fallback code doesn't even compile. We could
probably work around that, but then we'd be writing new untested code
for a computer that doesn't exist.
Instead, delete the unreachable and C23-uncompilable fallback code, and
let existing static assertions fail if the system-provided bool is too
wide. If we ever get a problem report from a real system, then it will
be time to figure out what to do about it in a way that also works on
modern compilers.
Note on C++: Previously we avoided including <stdbool.h> or trying to
define a new bool type in headers that might be included by C++ code.
These days we might as well just include <stdbool.h> unconditionally:
it should be visible to C++11 but do nothing, just as in C23. We
already include <stdint.h> without C++ guards in c.h, and that falls
under the same C99-compatibility section of the C++11 standard as
<stdbool.h>, so let's remove the guards here too.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3198438.1731895163%40sss.pgh.pa.us
Previously we checked "for <stdbool.h> that conforms to C99" using
autoconf's AC_HEADER_STDBOOL macro. We've required C99 since PostgreSQL
12, so the test was redundant, and under C23 it was broken: autoconf
2.69's implementation doesn't understand C23's new empty header (the
macros it's looking for went away, replaced by language keywords).
Later autoconf versions fixed that, but let's just remove the
anachronistic test.
HAVE_STDBOOL_H and HAVE__BOOL will no longer be defined, but they
weren't directly tested in core or likely extensions (except in 11, see
below). PG_USE_STDBOOL (or USE_STDBOOL in 11 and 12) is still defined
when sizeof(bool) is 1, which should be true on all modern systems.
Otherwise we define our own bool type and values of size 1, which would
fail to compile under C23 as revealed by the broken test. (We'll
probably clean that dead code up in master, but here we want a minimal
back-patchable change.)
This came to our attention when GCC 15 recently started using using C23
by default and failed to compile the replacement code, as reported by
Sam James and build farm animal alligator.
Back-patch to all supported releases, and then two older versions that
also know about <stdbool.h>, per the recently-out-of-support policy[1].
12 requires C99 so it's much like the supported releases, but 11 only
assumes C89 so it now uses AC_CHECK_HEADERS instead of the overly picky
AC_HEADER_STDBOOL. (I could find no discussion of which historical
systems had <stdbool.h> but failed the conformance test; if they ever
existed, they surely aren't relevant to that policy's goals.)
[1] https://wiki.postgresql.org/wiki/Committing_checklist#Policies
Reported-by: Sam James <sam@gentoo.org>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org> (master version)
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (approach)
Discussion: https://www.postgresql.org/message-id/flat/87o72eo9iu.fsf%40gentoo.org
Like INT64_FORMAT and UINT64_FORMAT, these macros produce format
strings for 64-bit integers. However, INT64_HEX_FORMAT and
UINT64_HEX_FORMAT generate the output in hexadecimal instead of
decimal. Besides introducing these macros, this commit makes use
of them in several places. This was originally intended to be part
of commit 5d6187d2a2, but I left it out because I felt there was a
nonzero chance that back-patching these new macros into c.h could
cause problems with third-party code. We tend to be less cautious
with such changes in new major versions.
Note that UINT64_HEX_FORMAT was originally added in commit
ee1b30f128, but it was placed in test_radixtree.c, so it wasn't
widely available. This commit moves UINT64_HEX_FORMAT to c.h.
Discussion: https://postgr.es/m/ZwQvtUbPKaaRQezd%40nathan
Presently, we check for compiler support for the required
intrinsics both with and without extra compiler flags (e.g.,
-mxsave), and then depending on the results of those checks, we
pick which files to compile with which flags. This is tedious and
complicated, and it results in unsustainable coding patterns such
as separate files for each portion of code may need to be built
with different compiler flags.
This commit introduces support for __attribute__((target(...))) and
uses it for the AVX-512 code. This simplifies both the
configure-time checks and the build scripts, and it allows us to
place the functions that use the intrinsics in files that we
otherwise do not want to build with special CPU instructions. We
are careful to avoid using __attribute__((target(...))) on
compilers that do not understand it, but we still perform the
configure-time checks in case the compiler allows using the
intrinsics without it (e.g., MSVC).
A similar change could likely be made for some of the CRC-32C code,
but that is left as a future exercise.
Suggested-by: Andres Freund
Reviewed-by: Raghuveer Devulapalli, Andres Freund
Discussion: https://postgr.es/m/20240731205254.vfpap7uxwmebqeaf%40awork3.anarazel.de
Commit 15abc7788e tolerated namespace pollution from BeOS system
headers. Commit 44f902122 de-supported BeOS. Since that stuff didn't
make it into the Meson build system, synchronize by removing from
configure.
Author: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (the idea, not the patch)
Discussion: https://postgr.es/m/ME3P282MB3166F9D1F71F787929C0C7E7B6312%40ME3P282MB3166.AUSP282.PROD.OUTLOOK.COM
Instead of XXX_IN_XLOCALE_H for several features XXX, let's just
include <xlocale.h> if HAVE_XLOCALE_H. The reason for the extra
complication was apparently that some old glibc systems also had an
<xlocale.h>, and you weren't supposed to include it directly, but it's
gone now (as far as I can tell it was harmless to do so anyway).
Author: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CWZBBRR6YA8D.8EHMDRGLCKCD%40neon.tech
fasthash_accum_cstring_aligned() uses a technique, found in various
strlen() implementations, to detect a string's NUL terminator by
reading a word at at time. That triggers failures when testing with
"-fsanitize=address", at least with frontend code. To enable using
this function anywhere, add a function attribute macro to disable
such testing.
Reviewed by Jeff Davis
Discussion: https://postgr.es/m/CANWCAZbwvp7oUEkbw-xP4L0_S_WNKq-J-ucP4RCNDPJnrakUPw%40mail.gmail.com
There isn't a lot of user demand for AIX support, we have a bunch of
hacks to work around AIX-specific compiler bugs and idiosyncrasies,
and no one has stepped up to the plate to properly maintain it.
Remove support for AIX to get rid of that maintenance overhead. It's
still supported for stable versions.
The acute issue that triggered this decision was that after commit
8af2565248, the AIX buildfarm members have been hitting this
assertion:
TRAP: failed Assert("(uintptr_t) buffer == TYPEALIGN(PG_IO_ALIGN_SIZE, buffer)"), File: "md.c", Line: 472, PID: 2949728
Apperently the "pg_attribute_aligned(a)" attribute doesn't work on AIX
for values larger than PG_IO_ALIGN_SIZE, for a static const variable.
That could be worked around, but we decided to just drop the AIX support
instead.
Discussion: https://www.postgresql.org/message-id/20240224172345.32@rfd.leadboat.com
Reviewed-by: Andres Freund, Noah Misch, Thomas Munro
- Remove MemoryContextAllocZeroAligned(). It was supposed to be a
faster version of MemoryContextAllocZero(), but modern compilers turn
the MemSetLoop() into a call to memset() anyway, making it more or
less identical to MemoryContextAllocZero(). That was the only user of
MemSetTest, MemSetLoop, so remove those too, as well as palloc0fast().
- Convert newNode() to a static inline function. When this was
originally originally written, it was written as a macro because
testing showed that gcc didn't inline the size check as we
intended. Modern compiler versions do, and now that it just calls
palloc0() there is no size-check to inline anyway.
One nice effect is that the palloc0() takes one less argument than
MemoryContextAllocZeroAligned(), which saves a few instructions in the
callers of newNode().
Reviewed-by: Peter Eisentraut, Tom Lane, John Naylor, Thomas Munro
Discussion: https://www.postgresql.org/message-id/b51f1fa7-7e6a-4ecc-936d-90a8a1659e7c@iki.fi
These two macros wouldn't work if used in an inline function definition
in a header seen by g++, because __builtin_types_compatible_p is only
available in C. Redirect to standard C++ const_cast (which also
adds/removes volatile despite its name).
Per cpluspluscheck failure in a development branch.
Suggested-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CA%2BhUKGK3OXFjkOyZiw-DgL2bUqk9by1uGuCnViJX786W%2BfyDSw%40mail.gmail.com
If we define ZLIB_CONST before including zlib.h, zlib augments some
interfaces with const decorations. By doing that we can keep our own
interfaces cleaner and can remove some unconstify calls.
ZLIB_CONST was introduced in zlib 1.2.5.2 (17 Dec 2011). When
compiling with older zlib releases, you might now get compiler
warnings about discarding qualifiers.
CentOS 6 has zlib 1.2.3, but in 8e278b6576, we removed support for the
OpenSSL release in CentOS 6, so it seems ok to de-support the zlib
release in CentOS 6 as well.
Reviewed-by: Tristan Partin <tristan@neon.tech>
Discussion: https://www.postgresql.org/message-id/flat/33462926-bb1e-7cc9-8d92-d86318e8ed1d%40eisentraut.org
In order to have the option to use O_DIRECT/FILE_FLAG_NO_BUFFERING in a
later commit, we need the addresses of user space buffers to be well
aligned. The exact requirements vary by OS and file system (typically
sectors and/or memory pages). The address alignment size is set to
4096, which is enough for currently known systems: it matches modern
sectors and common memory page size. There is no standard governing
O_DIRECT's requirements so we might eventually have to reconsider this
with more information from the field or future systems.
Aligning I/O buffers on memory pages is also known to improve regular
buffered I/O performance.
Three classes of I/O buffers for regular data pages are adjusted:
(1) Heap buffers are now allocated with the new palloc_aligned() or
MemoryContextAllocAligned() functions introduced by commit 439f6175.
(2) Stack buffers now use a new struct PGIOAlignedBlock to respect
PG_IO_ALIGN_SIZE, if possible with this compiler. (3) The buffer
pool is also aligned in shared memory.
WAL buffers were already aligned on XLOG_BLCKSZ. It's possible for
XLOG_BLCKSZ to be configured smaller than PG_IO_ALIGNED_SIZE and thus
for O_DIRECT WAL writes to fail to be well aligned, but that's a
pre-existing condition and will be addressed by a later commit.
BufFiles are not yet addressed (there's no current plan to use O_DIRECT
for those, but they could potentially get some incidental speedup even
in plain buffered I/O operations through better alignment).
If we can't align stack objects suitably using the compiler extensions
we know about, we disable the use of O_DIRECT by setting PG_O_DIRECT to
0. This avoids the need to consider systems that have O_DIRECT but
can't align stack objects the way we want; such systems could in theory
be supported with more work but we don't currently know of any such
machines, so it's easier to pretend there is no O_DIRECT support
instead. That's an existing and tested class of system.
Add assertions that all buffers passed into smgrread(), smgrwrite() and
smgrextend() are correctly aligned, unless PG_O_DIRECT is 0 (= stack
alignment tricks may be unavailable) or the block size has been set too
small to allow arrays of buffers to be all aligned.
Author: Thomas Munro <thomas.munro@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/CA+hUKGK1X532hYqJ_MzFWt0n1zt8trz980D79WbjwnT-yYLZpg@mail.gmail.com
New versions of perl trigger warnings within perl.h with our compiler
flags. At least -Wdeclaration-after-statement, -Wshadow=compatible-local are
known to be problematic.
To avoid these warnings, conditionally use #pragma GCC system_header before
including plperl.h.
Alternatively, we could add the include paths for problematic headers with
-isystem, but that is a larger hammer and is harder to search for.
A more granular alternative would be to use #pragma GCC diagnostic
push/ignored/pop, but gcc warns about unknown warnings being ignored, so every
to-be-ignored-temporarily compiler warning would require its own pg_config.h
symbol and #ifdef.
As the warnings are voluminous, it makes sense to backpatch this change. But
don't do so yet, we first want gather buildfarm coverage - it's e.g. possible
that some compiler claiming to be gcc compatible has issues with the pragma.
Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: Discussion: https://postgr.es/m/20221228182455.hfdwd22zztvkojy2@awork3.anarazel.de
The previous coding of VA_ARGS_NARGS() always returned 1 on Visual
Studio, because it treats __VA_ARGS__ as a single token unless you jump
through extra hoops. Newer compilers have an option to fix that. Add a
comment about that so that we can remember to clean this up in the
future when our minimum MSVC version advances.
Author: Victor Spirin <v.spirin@postgrespro.ru>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/f450fc57-a147-19d0-e50c-33571c52cc13%40postgrespro.ru
Because we added StaticAssertStmt() first before StaticAssertDecl(),
some uses as well as the instructions in c.h are now a bit backwards
from the "native" way static assertions are meant to be used in C.
This updates the guidance and moves some static assertions to better
places.
Specifically, since the addition of StaticAssertDecl(), we can put
static assertions at the file level. This moves a number of static
assertions out of function bodies, where they might have been stuck
out of necessity, to perhaps better places at the file level or in
header files.
Also, when the static assertion appears in a position where a
declaration is allowed, then using StaticAssertDecl() is more native
than StaticAssertStmt().
Reviewed-by: John Naylor <john.naylor@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/941a04e7-dd6f-c0e4-8cdf-a33b3338cbda%40enterprisedb.com
Remove the Trap and TrapMacro macros, which were nearly unused
and confusingly had the opposite condition polarity from the
otherwise-functionally-equivalent Assert macros.
Having done that, it's very hard to justify carrying the errorType
argument of ExceptionalCondition, so drop that too, and just
let it assume everything's an Assert. This saves about 64K
of code space as of current HEAD.
Discussion: https://postgr.es/m/3928703.1665345117@sss.pgh.pa.us
Instead of Abs() for int64, use the C standard functions labs() or
llabs() as appropriate. Define a small wrapper around them that
matches our definition of int64. (labs() is C90, llabs() is C99.)
Reviewed-by: Zhang Mingli <zmlpostgres@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/4beb42b5-216b-bce8-d452-d924d5794c63%40enterprisedb.com
Visual Studio 2015+ has support for a macro to control the alignement of
structures as of __declspec(align(#)), and this commit adds a definition
of pg_attribute_aligned() based on that. It happens that this was
already used in the implementation of atomics for MSVC. Note that there
is still no definition fo pg_attribute_packed(), so this does not impact
itemptr.h.
Author: James Coleman
Discussion: https://postgr.es/m/CAAaqYe-HbtZvR3msoMtk+hYW2S0e0OapzMW8icSMYTMA+mN8Aw@mail.gmail.com
<sys/un.h> is in SUSv3 and every targeted Unix has it. Some Windows
tool chains may still lack the approximately equivalent header
<afunix.h>, so we already defined struct sockaddr_un ourselves on that
OS for now. To harmonize things a bit, move our definition into a new
header src/include/port/win32/sys/un.h.
HAVE_UNIX_SOCKETS is now defined unconditionally. We migh remove that
in a separate commit, pending discussion.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKG%2BL_3brvh%3D8e0BW_VfX9h7MtwgN%3DnFHP5o7X2oZucY9dg%40mail.gmail.com
Previously we fell back to __FUNCTION__ and then NULL. As __func__ is in C99
that shouldn't be necessary anymore.
Solution.pm defined HAVE_FUNCNAME__FUNCTION instead of
HAVE_FUNCNAME__FUNC (originating in 4164e6636e), as at some point in the past
MSVC only supported __FUNCTION__. Our minimum version supports __func__.
Reviewed-By: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/20220807012914.ydz73yte6j3coulo@awork3.anarazel.de
strtoll was backfilled with either __strtoll or strtoq on systems without
strtoll. The last such system on the buildfarm was an ancient HP-UX animal. We
don't support HP-UX anymore, so remove.
On other systems strtoll was present, but did not have a declaration. The last
known instance on the buildfarm was running an ancient OSX and shut down in
2019.
Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/20220804013546.h65najrzig764jar@awork3.anarazel.de
Windows 10 gained support for flushing NTFS files with fdatasync()
semantics. The main advantage over open_datasync (in Windows API terms
FILE_FLAG_WRITE_THROUGH) is that the latter does not flush SATA drive
caches. The default setting is not changed, so users have to opt in to
this.
Discussion: https://postgr.es/m/CA%2BhUKGJZJVO%3DiX%2Beb-PXi2_XS9ZRqnn_4URh0NUQOwt6-_51xQ%40mail.gmail.com
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
pg_attribute_nonnull(...) can be used to generate compiler warnings
when a function is called with the specified arguments set to NULL, as
per an idea from Andres Freund. An empty argument list indicates that
no pointer arguments can be NULL. pg_attribute_nonnull() only works for
compilers that support the nonnull function attribute. If nonnull is
not supported, pg_attribute_nonnull() has no effect.
As a beginning, this commit uses it for the DefineCustomXXXVariable()
functions to generate warnings when the "name" and "value" arguments are
set to NULL. This will likely be expanded to other places in the
future, where it makes sense.
Author: Nathan Bossart
Reviewed by: Michael Paquier, Tom Lane
Discussion: https://postgr.es/m/20220525061739.ur7x535vtzyzkmqo@alap3.anarazel.de
pg_strtouint64() is a wrapper around strtoull/strtoul/_strtoui64, but
it seems no longer necessary to have this indirection.
msvc/Solution.pm claims HAVE_STRTOULL, so the "MSVC only" part seems
unnecessary. Also, we have code in c.h to substitute alternatives for
strtoull() if not found, and that would appear to cover all currently
supported platforms, so having a further fallback in pg_strtouint64()
seems unnecessary.
Therefore, we could remove pg_strtouint64(), and use strtoull()
directly in all call sites. However, it seems useful to keep a
separate notation for parsing exactly 64-bit integers, matching the
type definition int64/uint64. For that, add new macros strtoi64() and
strtou64() in c.h as thin wrappers around strtol()/strtoul() or
strtoll()/stroull(). This makes these functions available everywhere
instead of just in the server code, and it makes the function naming
notably different from the pg_strtointNN() functions in numutils.c,
which have a different API.
Discussion: https://www.postgresql.org/message-id/flat/a3df47c9-b1b4-29f2-7e91-427baf8b75a3%40enterprisedb.com
This reverts commits c2d1eea9e and 11b500072, as well as similar hacks
elsewhere, in favor of setting up the PGDLLIMPORT macro so that it can
just be used unconditionally. That can work because in frontend code,
we need no marking in either the defining or consuming files for a
variable exported from these libraries; and frontend code has no need
to access variables exported from the core backend, either.
While at it, write some actual documentation about the PGDLLIMPORT
and PGDLLEXPORT macros.
Patch by me, based on a suggestion from Robert Haas.
Discussion: https://postgr.es/m/1160385.1638165449@sss.pgh.pa.us
It's hard to avoid the conclusion that there is something wrong with
setjmp/longjmp on MinGW-64, as we have seen failures come and go after
entirely-unrelated-looking changes in our own code. Other projects
such as Ruby have given up and started using gcc's setjmp/longjmp
builtins on that platform; this patch just follows that lead.
Note that this is a pretty fundamental ABI break for functions
containining either setjmp or longjmp, so we can't really consider
a back-patch.
Per reports from Regina Obe and Heath Lord, as well as recent failures
on buildfarm member walleye, and less-recent failures on fairywren.
Juan José Santamaría Flecha
Discussion: https://postgr.es/m/000401d716a0$1ed0fc70$5c72f550$@pcorp.us
Discussion: https://postgr.es/m/CA+BEBhvHhM-Bn628pf-LsjqRh3Ang7qCSBG0Ga+7KwhGqrNUPw@mail.gmail.com
Discussion: https://postgr.es/m/f1caef93-9640-022e-9211-bbe8755a56b0@2ndQuadrant.com
Modern gcc and clang compilers offer alignment sanitizers, which help to detect
pointer misalignment. However, our codebase already contains x86-specific
crc32 computation code, which uses unalignment access. Thankfully, those
compilers also support the attribute, which disables alignment sanitizers at
the function level. This commit adds pg_attribute_no_sanitize_alignment(),
which wraps this attribute, and applies it to pg_comp_crc32c_sse42() function.
Discussion: https://postgr.es/m/CAPpHfdsne3%3DT%3DfMNU45PtxdhSL_J2PjLTeS8rwKnJzUR4YNd4w%40mail.gmail.com
Discussion: https://postgr.es/m/475514.1612745257%40sss.pgh.pa.us
Author: Alexander Korotkov, revised by Tom Lane
Reviewed-by: Tom Lane
This patch generalizes the subscripting infrastructure so that any
data type can be subscripted, if it provides a handler function to
define what that means. Traditional variable-length (varlena) arrays
all use array_subscript_handler(), while the existing fixed-length
types that support subscripting use raw_array_subscript_handler().
It's expected that other types that want to use subscripting notation
will define their own handlers. (This patch provides no such new
features, though; it only lays the foundation for them.)
To do this, move the parser's semantic processing of subscripts
(including coercion to whatever data type is required) into a
method callback supplied by the handler. On the execution side,
replace the ExecEvalSubscriptingRef* layer of functions with direct
calls to callback-supplied execution routines. (Thus, essentially
no new run-time overhead should be caused by this patch. Indeed,
there is room to remove some overhead by supplying specialized
execution routines. This patch does a little bit in that line,
but more could be done.)
Additional work is required here and there to remove formerly
hard-wired assumptions about the result type, collation, etc
of a SubscriptingRef expression node; and to remove assumptions
that the subscript values must be integers.
One useful side-effect of this is that we now have a less squishy
mechanism for identifying whether a data type is a "true" array:
instead of wiring in weird rules about typlen, we can look to see
if pg_type.typsubscript == F_ARRAY_SUBSCRIPT_HANDLER. For this
to be bulletproof, we have to forbid user-defined types from using
that handler directly; but there seems no good reason for them to
do so.
This patch also removes assumptions that the number of subscripts
is limited to MAXDIM (6), or indeed has any hard-wired limit.
That limit still applies to types handled by array_subscript_handler
or raw_array_subscript_handler, but to discourage other dependencies
on this constant, I've moved it from c.h to utils/array.h.
Dmitry Dolgov, reviewed at various times by Tom Lane, Arthur Zakirov,
Peter Eisentraut, Pavel Stehule
Discussion: https://postgr.es/m/CA+q6zcVDuGBv=M0FqBYX8DPebS3F_0KQ6OVFobGJPM507_SZ_w@mail.gmail.com
Discussion: https://postgr.es/m/CA+q6zcVovR+XY4mfk-7oNk-rF91gH0PebnNfuUjuuDsyHjOcVA@mail.gmail.com
The buildfarm animal walleye, running MinGW 8.1 has been having problems
ever since 697e1d02f and 913ec71d6 went in. This appears to be a bug in
assembler which was fixed in a later version.
For now, in order to get that animal running green again, let's just
define pg_attribute_cold and pg_attribute_hot to be empty macros on that
compiler. Hopefully, we can get the support of the owner of the animal to
upgrade to a less buggy compiler and revert this at a later date.
Discussion: https://postgr.es/m/286560.1606233316@sss.pgh.pa.us
1fa22a43a was a quick fix for portability problem I introduced in
697e1d02f. 1fa22a43a adds a few more cases to the preprocessor logic than
I'd have liked. Andres Freund and Dagfinn Ilmari Mannsåker suggested a
better way to do this.
In passing, also adjust the only current usage of these macros so that the
macro comes before the function's return type in the declaration of the
function. This now matches what the definition of the function does.
Discussion: https://postgr.es/m/20200625163553.lt6wocbjhklp5pl4@alap3.anarazel.de
Discussion: https://postgr.es/m/87pn43bmok.fsf@wibble.ilmari.org
This should fix the breakages caused by 697e1d02f, which seems to break
the build for GCC version < 5.
It seems, according to the GCC manual that __has_attribute is a "special
operator" and must be tested without any other conditions in the
preprocessor test.
Per recommendation from the GCC manual via Greg Nancarrow
Reported-by: Greg Nancarrow
Discussion: https://postgr.es/m/CAJcOf-euSu8fhC10v476o9dqnjqKysVs1_vRms-_fvajpZ3kFw@mail.gmail.com
For compilers supporting __has_attribute and __has_attribute (hot/cold).
__has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17.
A followup commit will implement some usages of these macros.
Author: David Rowley
Reviewed-by: Andres Freund, Peter Eisentraut
Discussion: https://postgr.es/m/CAApHDvrVpasrEzLL2er7p9iwZFZ%3DJj6WisePcFeunwfrV0js_A%40mail.gmail.com
pg_nodiscard means the compiler should warn if the result of a
function call is ignored. The name "nodiscard" is chosen in alignment
with (possibly future) C and C++ standards. It maps to the GCC
attribute warn_unused_result.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/e3753562-99cd-b65f-5aca-687dfd1ec2fc@2ndquadrant.com
They are equivalent, except that StrNCpy() zero-fills the entire
destination buffer instead of providing just one trailing zero. For
all but a tiny number of callers, that's just overhead rather than
being desirable.
Remove StrNCpy() as it is now unused.
In some cases, namestrcpy() is the more appropriate function to use.
While we're here, simplify the API of namestrcpy(): Remove the return
value, don't check for NULL input. Nothing was using that anyway.
Also, remove a few unused name-related functions.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/44f5e198-36f6-6cdb-7fa9-60e34784daae%402ndquadrant.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
Thomas Munro