Commit graph

452 commits

Author SHA1 Message Date
Michael Paquier
9181c870ba Improve type handling of varlena structures
This commit changes the definition of varlena to a typedef, so as it
becomes possible to remove "struct" markers from various declarations in
the code base.  Historically, "struct" markers are not the project style
for variable declarations, so this update simplifies the code and makes
it more consistent across the board.

This change has an impact on the following structures, simplifying
declarations using them:
- varlena
- varatt_indirect
- varatt_external

This cleanup has come up in a different path set that played with
TOAST and varatt.h, independently worth doing on its own.

Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Reviewed-by: Shinya Kato <shinya11.kato@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/aW8xvVbovdhyI4yo@paquier.xyz
2026-02-11 07:33:24 +09:00
Peter Eisentraut
955e507668 Change StaticAssertVariableIsOfType to be a declaration
This allows moving the uses to more natural and useful positions.
Also, a declaration is the more native use of static assertions in C.

Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/2273bc2a-045d-4a75-8584-7cd9396e5534%40eisentraut.org
2026-02-03 08:46:02 +01:00
Peter Eisentraut
137d05df2f Rename AssertVariableIsOfType to StaticAssertVariableIsOfType
This keeps run-time assertions and static assertions clearly separate.

Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/2273bc2a-045d-4a75-8584-7cd9396e5534%40eisentraut.org
2026-02-03 08:45:24 +01:00
Tom Lane
bd9dfac8b1 Further fix extended alignment for older g++.
Commit 6ceef9408 was still one brick shy of a load, because it caused
any usage at all of PGIOAlignedBlock or PGAlignedXLogBlock to fail
under older g++.  Notably, this broke "headerscheck --cplusplus".
We can permit references to these structs as abstract structs though;
only actual declaration of such a variable needs to be forbidden.

Discussion: https://www.postgresql.org/message-id/3119480.1769189606@sss.pgh.pa.us
2026-01-29 16:16:36 -05:00
Peter Eisentraut
6ceef9408c Disable extended alignment uses on older g++
Fix for commit a9bdb63bba.  The previous plan of redefining alignas
didn't work, because it interfered with other C++ header files (e.g.,
LLVM).  So now the new workaround is to just disable the affected
typedefs under the affected compilers.  These are not typically used
in extensions anyway.

Discussion: https://www.postgresql.org/message-id/3119480.1769189606%40sss.pgh.pa.us
2026-01-26 10:23:14 +01:00
Peter Eisentraut
a9bdb63bba Work around buggy alignas in older g++
Older g++ (<9.3) mishandle the alignas specifier (raise warnings that
the alignment is too large), but the more or less equivalent attribute
works.  So as a workaround, #define alignas to that attribute for
those versions.

see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89357>

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/3119480.1769189606%40sss.pgh.pa.us
2026-01-25 11:32:47 +01:00
Nathan Bossart
25dc485074 Refactor some SIMD and popcount macros.
This commit does the following:

* Removes TRY_POPCNT_X86_64.  We now assume that the required CPUID
intrinsics are available when HAVE_X86_64_POPCNTQ is defined, as we
have done since v16 for meson builds when
USE_SSE42_CRC32C_WITH_RUNTIME_CHECK is defined and since v17 when
USE_AVX512_POPCNT_WITH_RUNTIME_CHECK is defined.

* Moves the MSVC check for HAVE_X86_64_POPCNTQ to configure-time.
This way, we set it for all relevant platforms in one place.

* Moves the #defines for USE_SSE2 and USE_NEON to c.h so that they
can be used elsewhere without including simd.h.  Consequently, we
can remove the POPCNT_AARCH64 macro.

* Moves the #includes for pg_bitutils.h to below the system headers
in pg_popcount_{aarch64,x86}.c, since we no longer depend on macros
from pg_bitutils.h to decide which system headers to use.

Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Discussion: https://postgr.es/m/aWf_InS1VrbeXAfP%40nathan
2026-01-21 14:21:00 -06:00
Peter Eisentraut
b4555cb070 Fix for C++ compatibility
After commit 476b35d4e3, some buildfarm members are complaining about
not recognizing _Noreturn when building the new C++ module
test_cplusplusext.  This is not a C++ feature, but it was gated like

    #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
    #define pg_noreturn _Noreturn

But apparently that was not sufficient.  Some platforms define
__STDC_VERSION__ even in C++ mode.  (In this particular case, it was
g++ on Solaris, but apparently this is also done by some other
platforms, and it is allowed by the C++ standard.)  To fix, add a

    ... && !defined(__cplusplus)

Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/CAGECzQR21OnnKiZO_1rLWO0-16kg1JBxnVq-wymYW0-_1cUNtg@mail.gmail.com
2026-01-21 08:54:35 +01:00
Peter Eisentraut
fa16e7fd84 Revert "Replace pg_restrict by standard restrict"
This reverts commit f0f2c0c1ae.

The original problem that led to the use of pg_restrict was that MSVC
couldn't handle plain restrict, and defining it to something else
would conflict with its __declspec(restrict) that is used in system
header files.  In C11 mode, this is no longer a problem, as MSVC
handles plain restrict.  This led to the commit to replace pg_restrict
with restrict.  But this did not take C++ into account.  Standard C++
does not have restrict, so we defined it as something else (for
example, MSVC supports __restrict).  But this then again conflicts
with __declspec(restrict) in system header files.  So we have to
revert this attempt.  The comments are updated to clarify that the
reason for this is now C++ only.

Reported-by: Jelte Fennema-Nio <postgres@jeltef.nl>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/CAGECzQRoD7chJP1-dneSrhxUJv%2BBRcigoGOO4UwGzaShLot2Yw%40mail.gmail.com
2026-01-14 15:12:25 +01:00
Michael Paquier
b139bd3b6e Add data type oid8, 64-bit unsigned identifier
This new identifier type provides support for 64-bit unsigned values,
to be used in catalogs, like OIDs.  An advantage of a new data type is
that it becomes easier to grep for it in the code when assigning this
type to a catalog attribute, linking it to dedicated APIs and internal
structures.

The following operators are added in this commit, with dedicated tests:
- Casts with integer types and OID.
- btree and hash operators
- min/max functions.
- C type with related macros and defines, named around "Oid8".

This has been mentioned as useful on its own on the thread to add
support for 64-bit TOAST values, so as it becomes possible to attach
this data type to the TOAST code and catalog definitions.  However, as
this concept can apply to many more areas, it is implemented as its own
independent change.  This is based on a discussion with Andres Freund
and Tom Lane.

Bump catalog version.

Author: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Greg Burd <greg@burd.me>
Reviewed-by: Nikhil Kumar Veldanda <veldanda.nikhilkumar17@gmail.com>
Discussion: https://postgr.es/m/1891064.1754681536@sss.pgh.pa.us
2026-01-07 11:37:00 +09:00
Michael Paquier
b8cfcb9e00 Fix typos and inconsistencies in code and comments
This change is a cocktail of harmonization of function argument names,
grammar typos, renames for better consistency and unused code (see
ltree).  All of these have been spotted by the author.

Author: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/b2c0d0b7-3944-487d-a03d-d155851958ff@gmail.com
2026-01-05 09:19:15 +09:00
Bruce Momjian
451c43974f Update copyright for 2026
Backpatch-through: 14
2026-01-01 13:24:10 -05:00
Peter Eisentraut
17f446784d Refactor static_assert() support.
HAVE__STATIC_ASSERT was really a test for GCC statement expressions,
as needed for StaticAssertExpr() now that _Static_assert could be
assumed to be available through our C11 requirement.  This
artificially prevented Visual Studio from being able to use
static_assert() in other contexts.

Instead, make a new test for HAVE_STATEMENT_EXPRESSIONS, and use that
to control only whether StaticAssertExpr() uses fallback code, not the
other variants.  This improves the quality of failure messages in the
(much more common) other variants under Visual Studio.

Also get rid of the two separate implementations for C++, since the C
implementation is also also valid as C++11.  While it is a stretch to
apply HAVE_STATEMENT_EXPRESSIONS tested with $CC to a C++ compiler,
the previous C++ coding assumed that the C++ compiler had them
unconditionally, so it isn't a new stretch.  In practice, the C and
C++ compilers are very likely to agree, and if a combination is ever
reported that falsifies this assumption we can always reconsider that.

Author: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGKvr0x_oGmQTUkx%3DODgSksT2EtgCA6LmGx_jQFG%3DsDUpg%40mail.gmail.com
2025-12-15 11:54:23 +01:00
Peter Eisentraut
795e94c70c Make <assert.h> consistently available in frontend and backend
Previously, c.h made <assert.h> only available in frontends (#ifdef
FRONTEND), which was probably reasonable, because the only thing it
would give you is assert(), which you generally shouldn't use in the
backend.  But with C11, <assert.h> also makes available
static_assert(), which would be useful everywhere.  So this patch
moves <assert.h> to the commonly available header files in c.h and
fixes a small complication in regcustom.h that resulted from that.

Co-authored-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CA%2BhUKGKvr0x_oGmQTUkx%3DODgSksT2EtgCA6LmGx_jQFG%3DsDUpg%40mail.gmail.com
2025-12-11 09:56:57 +01:00
Tom Lane
0909380e4c Allow PG_PRINTF_ATTRIBUTE to be different in C and C++ code.
Although clang claims to be compatible with gcc's printf format
archetypes, this appears to be a falsehood: it likes __syslog__
(which gcc does not, on most platforms) and doesn't accept
gnu_printf.  This means that if you try to use gcc with clang++
or clang with g++, you get compiler warnings when compiling
printf-like calls in our C++ code.  This has been true for quite
awhile, but it's gotten more annoying with the recent appearance
of several buildfarm members that are configured like this.

To fix, run separate probes for the format archetype to use with the
C and C++ compilers, and conditionally define PG_PRINTF_ATTRIBUTE
depending on __cplusplus.

(We could alternatively insist that you not mix-and-match C and
C++ compilers; but if the case works otherwise, this is a poor
reason to insist on that.)

No back-patch for now, but we may want to do that if this
patch survives buildfarm testing.

Discussion: https://postgr.es/m/986485.1764825548@sss.pgh.pa.us
2025-12-10 17:09:10 -05:00
Heikki Linnakangas
bd8d9c9bdf Widen MultiXactOffset to 64 bits
This eliminates MultiXactOffset wraparound and the 2^32 limit on the
total number of multixid members. Multixids are still limited to 2^31,
but this is a nice improvement because 'members' can grow much faster
than the number of multixids. On such systems, you can now run longer
before hitting hard limits or triggering anti-wraparound vacuums.

Not having to deal with MultiXactOffset wraparound also simplifies the
code and removes some gnarly corner cases.

We no longer need to perform emergency anti-wraparound freezing
because of running out of 'members' space, so the offset stop limit is
gone. But you might still not want 'members' to consume huge amounts
of disk space. For that reason, I kept the logic for lowering vacuum's
multixid freezing cutoff if a large amount of 'members' space is
used. The thresholds for that are roughly the same as the "safe" and
"danger" thresholds used before, 2 billion transactions and 4 billion
transactions. This keeps the behavior for the freeze cutoff roughly
the same as before. It might make sense to make this smarter or
configurable, now that the threshold is only needed to manage disk
usage, but that's left for the future.

Add code to pg_upgrade to convert multitransactions from the old to
the new format, rewriting the pg_multixact SLRU files. Because
pg_upgrade now rewrites the files, we can get rid of some hacks we had
put in place to deal with old bugs and upgraded clusters. Bump catalog
version for the pg_multixact/offsets format change.

Author: Maxim Orlov <orlovmg@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: wenhui qiu <qiuwenhuifx@gmail.com>
Discussion: https://www.postgresql.org/message-id/CACG%3DezaWg7_nt-8ey4aKv2w9LcuLthHknwCawmBgEeTnJrJTcw@mail.gmail.com
2025-12-09 13:53:03 +02:00
Peter Eisentraut
1b2bb5077e Change Pointer to void *
The comment for the Pointer type said 'XXX Pointer arithmetic is done
with this, so it can't be void * under "true" ANSI compilers.'.  This
has been fixed in the previous commit 756a436893.  This now changes
the definition of the type from char * to void *, as envisaged by that
comment.

Extension code that relies on using Pointer for pointer arithmetic
will need to make changes similar to commit 756a436893, but those
changes would be backward compatible.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://www.postgresql.org/message-id/4154950a-47ae-4223-bd01-1235cc50e933%40eisentraut.org
2025-12-03 10:22:17 +01:00
Peter Eisentraut
d4c0f91f7d C11 alignas instead of unions -- extended alignments
This replaces some uses of pg_attribute_aligned() with the standard
alignas() for cases where extended alignment (larger than max_align_t)
is required.

This patch stipulates that all supported compilers must support
alignments up to PG_IO_ALIGN_SIZE, but that seems pretty likely.

We can then also desupport the case where direct I/O is disabled
because pg_attribute_aligned is not supported.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/46f05236-d4d4-4b4e-84d4-faa500f14691%40eisentraut.org
2025-11-24 07:39:37 +01:00
Peter Eisentraut
97e04c74be C11 alignas instead of unions
This changes a few union members that only existed to ensure
alignments and replaces them with the C11 alignas specifier.

This change only uses fundamental alignments (meaning approximately
alignments of basic types), which all C11 compilers must support.
There are opportunities for similar changes using extended alignments,
for example in PGIOAlignedBlock, but these are not necessarily
supported by all compilers, so they are kept as a separate change.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/46f05236-d4d4-4b4e-84d4-faa500f14691%40eisentraut.org
2025-11-21 10:08:24 +01:00
Peter Eisentraut
300c8f5324 Add <stdalign.h> to c.h
This allows using the C11 constructs alignas and alignof (not done in
this patch).

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/46f05236-d4d4-4b4e-84d4-faa500f14691%40eisentraut.org
2025-11-19 08:18:25 +01:00
David Rowley
586d63214e Adjust MemSet macro to use size_t rather than long
Likewise for MemSetAligned.

"long" wasn't the most suitable type for these macros as with MSVC in
64-bit builds, sizeof(long) == 4, which is narrower than the processor's
word size, therefore these macros had to perform twice as many loops as
they otherwise might.

Author: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CAApHDvoGFjSA3aNyVQ3ivbyc4ST=CC5L-_VjEUQ92HbE2Cxovg@mail.gmail.com
2025-11-17 12:27:00 +13:00
Jeff Davis
3853a6956c Use C11 char16_t and char32_t for Unicode code points.
Reviewed-by: Tatsuo Ishii <ishii@postgresql.org>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/bedcc93d06203dfd89815b10f815ca2de8626e85.camel%40j-davis.com
2025-10-29 14:17:13 -07:00
Peter Eisentraut
f0f2c0c1ae Replace pg_restrict by standard restrict
MSVC in C11 mode supports the standard restrict qualifier, so we don't
need the workaround naming pg_restrict anymore.

Even though restrict is in C99 and should be supported by all
supported compilers, we keep the configure test and the hardcoded
redirection to __restrict, because that will also work in C++ in all
supported compilers.  (restrict is not part of the C++ standard.)

For backward compatibility for extensions, we keep a #define of
pg_restrict around, but our own code doesn't use it anymore.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/0e3d8644-c01d-4374-86ea-9f0a987981f0%40eisentraut.org
2025-10-29 07:52:58 +01:00
Peter Eisentraut
c094be259b Remove obsolete comment
The comment "type prefixes (const, signed, volatile, inline) are
handled in pg_config.h." has been mostly not true for a long time.
2025-10-29 07:32:21 +01:00
Peter Eisentraut
8e2acda2b0 Rename pg_builtin_integer_constant_p to pg_integer_constant_p
Since it's not builtin.  Also fix a related typo.

Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAApHDvom02B_XNVSkvxznVUyZbjGAR%2B5myA89ZcbEd3%3DPA9UcA%40mail.gmail.com
2025-09-30 21:15:46 +02:00
David Rowley
59c2f03d1e Teach MSVC that elog/ereport ERROR doesn't return
It had always been intended that this already works correctly as
pg_unreachable() uses __assume(0) on MSVC, and that directs the compiler
in a way so it knows that a given function won't return.  However, with
ereport_domain(), it didn't work...

It's now understood that the failure to determine that elog(ERROR) does not
return comes from the inability of the MSVC compiler to detect the "const
int elevel_" is the same as the "elevel" macro parameter.  MSVC seems to be
unable to make the "if (elevel_ >= ERROR) branch constantly-true when the
macro is used with any elevel >= ERROR, therefore the pg_unreachable() is
seen to only be present in a *conditional* branch rather than present
*unconditionally*.

While there seems to be no way to force the compiler into knowing that
elevel_ is equal to elevel within the ereport_domain() macro, there is a
way in C11 to determine if the elevel parameter is a compile-time
constant or not.  This is done via some hackery using the _Generic()
intrinsic function, which gives us functionality similar to GCC's
__builtin_constant_p(), albeit only for integers.

Here we define pg_builtin_integer_constant_p() for this purpose.
Callers can check for availability via HAVE_PG_BUILTIN_INTEGER_CONSTANT_P.
ereport_domain() has been adjusted to use
pg_builtin_integer_constant_p() instead of __builtin_constant_p().

It's not quite clear at this stage if this now allows us to forego doing
the likes of "return NULL; /* keep compiler quiet */" as there may be other
compilers in use that have similar struggles.  It's just a matter of time
before someone commits a function that does not "return" a value after
an elog(ERROR).  Let's make time and lack of complaints about said commit
be the judge of if we need to continue the "/* keep compiler quiet */"
palaver.

Author: David Rowley <drowleyml@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CAApHDvom02B_XNVSkvxznVUyZbjGAR+5myA89ZcbEd3=PA9UcA@mail.gmail.com
2025-09-27 22:41:04 +12:00
Peter Eisentraut
a5b35fcedb Remove PointerIsValid()
This doesn't provide any value over the standard style of checking the
pointer directly or comparing against NULL.

Also remove related:
- AllocPointerIsValid() [unused]
- IndexScanIsValid() [had one user]
- HeapScanIsValid() [unused]
- InvalidRelation [unused]

Leaving HeapTupleIsValid(), ItemIdIsValid(), PortalIsValid(),
RelationIsValid for now, to reduce code churn.

Reviewed-by: Jacob Champion <jacob.champion@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/ad50ab6b-6f74-4603-b099-1cd6382fb13d%40eisentraut.org
Discussion: https://www.postgresql.org/message-id/CA+hUKG+NFKnr=K4oybwDvT35dW=VAjAAfiuLxp+5JeZSOV3nBg@mail.gmail.com
Discussion: https://www.postgresql.org/message-id/bccf2803-5252-47c2-9ff0-340502d5bd1c@iki.fi
2025-09-24 15:17:20 +02:00
Nathan Bossart
18cdf5932a Fix obsolete references to postgres.h in comments.
Oversights in commits d08741eab5 and d952373a98.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/aMxbfSJ2wLWd32x-%40nathan
2025-09-19 09:19:03 -05:00
Peter Eisentraut
25f36066dd Remove traces of support for Sun Studio compiler
Per discussion, this compiler suite is no longer maintained, and
it has not been able to compile PostgreSQL since at least PostgreSQL
17.

This removes all the remaining support code for this compiler.

Note that the Solaris operating system continues to be supported, but
using GCC as the compiler.

Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/a0f817ee-fb86-483a-8a14-b6f7f5991b6e%40eisentraut.org
2025-09-12 07:39:05 +02:00
Peter Eisentraut
4fbe015145 Remove checks for no longer supported GCC versions
Since commit f5e0186f86 (Raise C requirement to C11), we effectively
require at least GCC version 4.7, so checks for older versions can be
removed.

Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/a0f817ee-fb86-483a-8a14-b6f7f5991b6e%40eisentraut.org
2025-09-11 12:05:59 +02:00
Tom Lane
ee54046601 Grab the low-hanging fruit from forcing USE_FLOAT8_BYVAL to true.
Remove conditionally-compiled code for the other case.

Replace uses of FLOAT8PASSBYVAL with constant "true", mainly because
it was quite confusing in cases where the type we were dealing with
wasn't float8.

I left the associated pg_control and Pg_magic_struct fields in place.
Perhaps we should get rid of them, but it would save little, so it
doesn't seem worth thinking hard about the compatibility implications.
I just labeled them "vestigial" in places where that seemed helpful.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/1749799.1752797397@sss.pgh.pa.us
2025-08-13 17:18:22 -04:00
Peter Eisentraut
73d33be4da Remove INT64_HEX_FORMAT and UINT64_HEX_FORMAT
These were introduced (commit efdc7d7475) at the same time as we were
moving to using the standard inttypes.h format macros (commit
a0ed19e0a9).  It doesn't seem useful to keep a new already-deprecated
interface like this with only a few users, so remove the new symbols
again and have the callers use PRIx64.

(Also, INT64_HEX_FORMAT was kind of a misnomer, since hex formats all
use unsigned types.)

Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/0ac47b5d-e5ab-4cac-98a7-bdee0e2831e4%40eisentraut.org
2025-08-06 11:08:10 +02:00
Andres Freund
d65eb5b1b8 Add pg_assume(expr) macro
This macro can be used to avoid compiler warnings, particularly when using -O3
and not using assertions, and to get the compiler to generate better code.

A subsequent commit introduces a first user.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3prdb6hkep3duglhsujrn52bkvnlkvhc54fzvph2emrsm4vodl@77yy6j4hkemb
Discussion: https://postgr.es/m/20230316172818.x6375uvheom3ibt2%40awork3.anarazel.de
Discussion: https://postgr.es/m/20240207203138.sknifhlppdtgtxnk%40awork3.anarazel.de
2025-07-09 18:38:05 -04:00
Peter Eisentraut
8fd9bb1d96 Enable MSVC conforming preprocessor
Switch MSVC to use the conforming preprocessor, using the
/Zc:preprocessor option.

This allows us to drop the alternative implementation of
VA_ARGS_NARGS() for the previous "traditional" preprocessor.

This also prepares the way for enabling C11 mode in the future, which
enables the conforming preprocessor by default.

This now requires Visual Studio 2019.  The installation documentation
is adjusted accordingly.

Discussion: https://www.postgresql.org/message-id/flat/01a69441-af54-4822-891b-ca28e05b215a%40eisentraut.org
2025-07-01 09:41:40 +02:00
Andrew Dunstan
8f5e419484 Revert "Use workaround of __builtin_setjmp only on MINGW on MSVCRT"
This reverts commit c313fa4602.

This is found to cause issues on x86_64 Windows even when using UCRT.

Discussion: https://postgr.es/m/3312149.1744001936@sss.pgh.pa.us
2025-04-07 11:01:15 -04:00
Andrew Dunstan
c313fa4602 Use workaround of __builtin_setjmp only on MINGW on MSVCRT
MSVCRT is not present Windows/ARM64 and the workaround is not
necessary on any UCRT based toolchain.

Author: Lars Kanis <lars@greiz-reinsdorf.de>

Discussion: https://postgr.es/m/CAHXCYb2OjNHtoGVKyXtXmw4B3bUXwJX6M-Lcp1KcMCRUMLOocA@mail.gmail.com
2025-04-01 16:24:59 -04:00
Peter Eisentraut
2247281c47 Cast result of i64abs() back to int64
Without the cast, the return type could be long or long long,
depending on what int64 is underneath.  This doesn't affect code
correctness, but it could result in format-mismatch warnings when
attempting to printf such values using PRId64.

Reported-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+hUKGJc4s+Wyb3EFOQNN9VVK+Qv40r2LK41o9PkS9ThxviTvQ@mail.gmail.com
2025-03-28 14:34:57 +01:00
Peter Eisentraut
05cbd6cb22 Swap order of extern/static and pg_nodiscard
When pg_nodiscard was first added, the C standard draft had it as a
function specifier, and so the code comment about placement was
written with that in mind.  The final C23 standard has it as an
attribute and the placement rules are a bit different for that.
Specifically, it needs to be before extern or static.  (Or at least
both current clang and gcc require that.)  So just swap these.  (To be
clear: The current implementation with gcc attributes doesn't care.
This change is just for maximum forward compatibility for non-gcc
compilers.)  This also keeps the order consistent with the previously
introduced pg_noreturn.  Also update the code comment to reflect the
mentioned developments since its introduction.

Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/pxr5b3z7jmkpenssra5zroxi7qzzp6eswuggokw64axmdixpnk@zbwxuq7gbbcw
2025-03-14 07:18:07 +01:00
Peter Eisentraut
3691edfab9 pg_noreturn to replace pg_attribute_noreturn()
We want to support a "noreturn" decoration on more compilers besides
just GCC-compatible ones, but for that we need to move the decoration
in front of the function declaration instead of either behind it or
wherever, which is the current style afforded by GCC-style attributes.
Also rename the macro to "pg_noreturn" to be similar to the C11
standard "noreturn".

pg_noreturn is now supported on all compilers that support C11 (using
_Noreturn), as well as GCC-compatible ones (using __attribute__, as
before), as well as MSVC (using __declspec).  (When PostgreSQL
requires C11, the latter two variants can be dropped.)

Now, all supported compilers effectively support pg_noreturn, so the
extra code for !HAVE_PG_ATTRIBUTE_NORETURN can be dropped.

This also fixes a possible problem if third-party code includes
stdnoreturn.h, because then the current definition of

    #define pg_attribute_noreturn() __attribute__((noreturn))

would cause an error.

Note that the C standard does not support a noreturn attribute on
function pointer types.  So we have to drop these here.  There are
only two instances at this time, so it's not a big loss.  In one case,
we can make up for it by adding the pg_noreturn to a wrapper function
and adding a pg_unreachable(), in the other case, the latter was
already done before.

Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/pxr5b3z7jmkpenssra5zroxi7qzzp6eswuggokw64axmdixpnk@zbwxuq7gbbcw
2025-03-13 12:37:26 +01:00
Peter Eisentraut
74938d1320 IWYU widely useful pragmas
Add various widely useful "IWYU pragma" annotations, such as

- Common header files such as c.h, postgres.h should be "always_keep".

- System headers included in c.h, postgres.h etc. should be considered
  "export".

- Some portability headers such as getopt_long.h should be
  "always_keep", so they are not considered superfluous on some
  platforms.

- Certain system headers included from portability headers should be
  considered "export" because the purpose of the portability header is
  to wrap them.

- Superfluous includes marked as "for backward compatibility" get a
  formal IWYU annotation.

- Generated header included in utils/syscache.h is marked exported.
  This is a very commonly used include and this avoids lots of
  complaints.

Discussion: https://www.postgresql.org/message-id/flat/9395d484-eff4-47c2-b276-8e228526c8ae@eisentraut.org
2025-01-15 18:57:53 +01:00
Bruce Momjian
50e6eb731d Update copyright for 2025
Backpatch-through: 13
2025-01-01 11:21:55 -05:00
Thomas Munro
71cb352904 Fix header inclusion order in c.h.
Commit 962da900a added #include <stdint.h> to postgres_ext.h, which
broke c.h's header ordering rule.

The system headers on some systems would then lock down off_t's size in
private macros, before they'd had a chance to see our definition of
_FILE_OFFSET_BITS (and presumably other things).  This was picked up by
perl's ABI compatibility checks on some 32 bit systems in the build
farm.

Move #include "postgres_ext.h" down below the system header section, and
make the comments clearer (thanks to Tom for the new wording).

Diagnosed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/2397643.1733347237%40sss.pgh.pa.us
2024-12-05 14:31:39 +13:00
Thomas Munro
962da900ac Use <stdint.h> and <inttypes.h> for c.h integers.
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
2024-12-04 15:05:38 +13:00
Thomas Munro
97525bc5c8 Require sizeof(bool) == 1.
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
2024-11-28 12:01:14 +13:00
Thomas Munro
bc5a4dfcf7 Assume that <stdbool.h> conforms to the C standard.
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
2024-11-25 20:54:28 +13:00
Nathan Bossart
efdc7d7475 Add INT64_HEX_FORMAT and UINT64_HEX_FORMAT to c.h.
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
2024-11-22 12:41:57 -06:00
Nathan Bossart
f78667bd91 Use __attribute__((target(...))) for AVX-512 support.
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
2024-11-07 13:58:43 -06:00
Peter Eisentraut
a2d9a9b95a Remove traces of BeOS.
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
2024-10-14 08:33:36 +02:00
Peter Eisentraut
9c2a6c5a5f Simplify checking for xlocale.h
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
2024-10-01 07:23:45 -04:00
John Naylor
db17594ad7 Add macro to disable address safety instrumentation
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
2024-04-06 12:20:40 +07:00