glibc/include
Joseph Myers b34b46b880 Implement C23 <stdbit.h>
C23 adds a header <stdbit.h> with various functions and type-generic
macros for bit-manipulation of unsigned integers (plus macro defines
related to endianness).  Implement this header for glibc.

The functions have both inline definitions in the header (referenced
by macros defined in the header) and copies with external linkage in
the library (which are implemented in terms of those macros to avoid
duplication).  They are documented in the glibc manual.  Tests, as
well as verifying results for various inputs (of both the macros and
the out-of-line functions), verify the types of those results (which
showed up a bug in an earlier version with the type-generic macro
stdc_has_single_bit wrongly returning a promoted type), that the
macros can be used at top level in a source file (so don't use ({})),
that they evaluate their arguments exactly once, and that the macros
for the type-specific functions have the expected implicit conversions
to the relevant argument type.

Jakub previously referred to -Wconversion warnings in type-generic
macros, so I've included a test with -Wconversion (but the only
warnings I saw and fixed from that test were actually in inline
functions in the <stdbit.h> header - not anything coming from use of
the type-generic macros themselves).

This implementation of the type-generic macros does not handle
unsigned __int128, or unsigned _BitInt types with a width other than
that of a standard integer type (and C23 doesn't require the header to
handle such types either).  Support for those types, using the new
type-generic built-in functions Jakub's added for GCC 14, can
reasonably be added in a followup (along of course with associated
tests).

This implementation doesn't do anything special to handle C++, or have
any tests of functionality in C++ beyond the existing tests that all
headers can be compiled in C++ code; it's not clear exactly what form
this header should take in C++, but probably not one using macros.

DIS ballot comment AT-107 asks for the word "count" to be added to the
names of the stdc_leading_zeros, stdc_leading_ones,
stdc_trailing_zeros and stdc_trailing_ones functions and macros.  I
don't think it's likely to be accepted (accepting any technical
comments would mean having an FDIS ballot), but if it is accepted at
the WG14 meeting (22-26 January in Strasbourg, starting with DIS
ballot comment handling) then there would still be time to update
glibc for the renaming before the 2.39 release.

The new functions and header are placed in the stdlib/ directory in
glibc, rather than creating a new toplevel stdbit/ or putting them in
string/ alongside ffs.

Tested for x86_64 and x86.
2024-01-03 12:07:14 +00:00
..
arpa Fix all the remaining misspellings -- BZ 25337 2023-06-02 01:39:48 +00:00
bits Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
gnu Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
net Fix resolver if_* namespace (bug 17717). 2014-12-16 18:18:49 +00:00
netinet nss_files: Consolidate line parse declarations in <nss_files.h> 2020-07-21 07:33:20 +02:00
programs Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
protocols (abmon): Remove spaces. 1998-11-12 18:03:43 +00:00
rpc Handle out-of-memory case in svc_tcp.c/svc_unix.c:rendezvous_request. 2020-12-10 11:11:20 +01:00
rpcsvc Remove --enable-obsolete-nsl configure flag 2020-07-08 17:25:57 +02:00
sys Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
aio.h Linux: Move aio_suspend, aio_suspend64, __aio_suspend_time64 to libc 2021-06-25 11:55:27 +02:00
aliases.h Move 'aliases' routines from 'inet' into 'nss' 2023-10-24 12:30:59 +02:00
alloc_buffer.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
alloca.h Remove macros extend_alloca, extend_alloca_account [BZ #18023] 2018-06-27 19:20:37 +02:00
allocate_once.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
ar.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
argp-fmtstream.h Mark internal argp functions with attribute_hidden [BZ #18822] 2017-10-01 15:10:27 -07:00
argp.h ldbl-opt: Add argp_error and argp_failure (bug 23983) 2019-03-01 15:21:32 -03:00
argz.h Use libc_hidden_* for argz_next, __argz_next (bug 15105). 2018-02-15 21:00:02 +00:00
array_length.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
assert.h assert: Do not use stderr in libc-internal assert 2022-08-03 11:43:04 +02:00
atomic_wide_counter.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
atomic.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
byteswap.h
clone_internal.h posix: Add pidfd_spawn and pidfd_spawnp (BZ 30349) 2023-09-05 13:08:59 -03:00
complex.h float128: Add private _Float128 declarations for libm. 2017-05-15 10:23:28 -03:00
cpio.h Add more headers to include/ for conform tests. 2014-12-11 21:41:30 +00:00
ctype.h Use libc_hidden_* for tolower, toupper (bug 15105). 2018-02-23 13:54:53 +00:00
des.h
dirent.h Use 64 bit time_t stat internally 2021-06-22 12:09:52 -03:00
dlfcn.h elf: Remove LD_PROFILE for static binaries 2023-11-21 16:15:42 -03:00
dso_handle.h Mark __dso_handle as hidden [BZ #18822] 2017-09-26 16:53:44 -07:00
elf.h elf: Refuse to dlopen PIE objects [BZ #24323] 2019-06-18 16:42:10 +02:00
endian.h Update. 2001-03-30 05:34:59 +00:00
envz.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
err.h ldbl-128ibm-compat: PLT redirects for using ldbl redirects internally 2020-03-25 14:34:23 -05:00
errno.h Remove tls.h inclusion from internal errno.h 2020-11-13 12:59:19 -03:00
error.h Mark various cold functions as __COLD 2023-05-01 19:33:21 +02:00
execinfo.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
fcntl.h Fix Linux fcntl OFD locks for non-LFS architectures (BZ#20251) 2018-06-26 13:22:53 -03:00
features-time64.h y2038: Add support for 64-bit time on legacy ABIs 2021-06-15 10:42:11 -03:00
features.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
fenv.h Move fenv.h soft-float inlines from fenv_private.h to include/fenv.h. 2018-09-04 19:52:06 +00:00
file_change_detection.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
filename.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
float.h Make totalorder and totalordermag functions take pointer arguments. 2019-08-15 15:18:34 +00:00
fmtmsg.h Add more headers to include/ for conform tests. 2014-12-11 21:41:30 +00:00
fnmatch.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
fpu_control.h Hide internal __setfpucw function [BZ #18822] 2017-10-01 17:52:15 -07:00
fstab.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
fts.h io: Add fts64 with 64-bit time_t support 2021-06-15 10:42:11 -03:00
ftw.h io: Add ftw64 with 64-bit time_t support 2021-06-15 10:42:11 -03:00
gconv.h
getopt_int.h Update. 2004-03-09 10:36:53 +00:00
getopt.h getopt: remove USE_NONOPTION_FLAGS 2017-04-07 07:45:53 -04:00
glob.h Fix extra PLT reference in libc.so due to __glob64_time64 if build with gcc 7.5 on 32bit. 2021-07-01 16:46:59 +02:00
gmp.h Apply asm redirection in gmp.h before first use 2022-11-07 10:40:21 -03:00
gnu-versions.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
grp-merge.h Remove 'grp' and merge into 'nss' and 'posix' 2023-10-24 12:30:59 +02:00
grp.h Remove 'grp' and merge into 'nss' and 'posix' 2023-10-24 12:30:59 +02:00
gshadow.h Remove 'gshadow' and merge into 'nss' 2023-10-24 12:30:59 +02:00
iconv.h Update. 1999-08-21 00:38:15 +00:00
idx.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
ifaddrs.h nscd: Do not rebuild getaddrinfo (bug 30709) 2023-08-11 10:10:16 +02:00
ifreq.h Hide internal __ifreq function [BZ #18822] 2017-10-01 17:35:46 -07:00
ifunc-impl-list.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
inline-hashtab.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
intprops.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
inttypes.h Make strtoimax, strtoumax, wcstoimax, wcstoumax into aliases 2020-12-08 18:15:27 +00:00
langinfo.h Add first fixes for conformtest for POSIX2008 2012-02-26 21:32:56 -05:00
lastlog.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
libc-diag.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
libc-internal.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
libc-pointer-arith.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
libc-symbols.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
libgen.h
libintl.h Document the internal _ and N_ macros 2020-05-06 17:35:40 +02:00
limits.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
link.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
list_t.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
list.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
locale.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
loop_unroll.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
malloc.h Simplify __malloc_initialized 2021-07-22 18:38:04 +05:30
math-narrow-eval.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
math.h Redirect fma calls to __fma in libm 2021-09-15 22:57:35 +00:00
mcheck.h mcheck: Wean away from malloc hooks [BZ #23489] 2021-07-22 18:38:02 +05:30
memory.h
mntent.h Hide internal __hasmntopt function [BZ #18822] 2017-10-01 17:37:42 -07:00
monetary.h Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 2020-04-30 08:52:08 -05:00
mqueue.h Linux: Move mq_send, mq_timedsend, __mq_timedsend_time64 to libc 2021-06-25 12:21:12 +02:00
netdb.h Move 'netgroup' routines from 'inet' into 'nss' 2023-10-24 12:30:59 +02:00
netgroup.h Move 'netgroup' routines from 'inet' into 'nss' 2023-10-24 12:30:59 +02:00
nl_types.h
nss_dns.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
nss_files.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
nss.h nss: Export nscd hash function as __nss_hash [BZ #22459] 2017-11-23 14:08:11 +01:00
nsswitch.h
obstack.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
plural-exp.h Hide internal __gettextparse function [BZ #18822] 2017-10-01 17:31:05 -07:00
poll.h Update. 2000-08-21 16:02:48 +00:00
printf_buffer.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
printf.h stdio-common: Convert vfprintf and related functions to buffers 2022-12-19 18:56:54 +01:00
pthread.h Linux: Move mq_notify from librt to libc 2021-06-25 12:20:47 +02:00
pty.h login: Move libutil into libc 2021-06-30 08:43:37 +02:00
pwd.h Remove 'pwd' and merge into 'nss' 2023-10-24 12:30:59 +02:00
random-bits.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
re_comp.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
regex.h Fix regex type usage 2023-05-01 09:08:59 -04:00
regexp.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
register-atfork.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
resolv.h resolv: Add internal __res_binary_hnok function 2022-08-30 10:02:49 +02:00
rounding-mode.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
rtld-malloc.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
sched.h Add hidden prototypes for __sched_getparam, __sched_getscheduler 2020-02-20 08:57:01 +01:00
scratch_buffer.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
search.h misc: Add twalk_r function 2019-05-02 11:42:51 +02:00
set-freeres.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
setjmp.h chk: Add and fix hidden builtin definitions for *_chk 2023-08-03 22:46:48 +02:00
sgtty.h
shadow.h Remove 'shadow' and merge into 'nss' 2023-10-24 12:30:59 +02:00
shlib-compat.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
shm-directory.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
signal.h stdio: Remove the usage of $(fno-unit-at-a-time) for siglist.c 2022-05-13 10:54:41 -03:00
spawn.h posix: Use posix_spawn for wordexp 2019-10-09 17:48:41 -03:00
stab.h
stackinfo.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
stap-probe.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
stdbit.h Implement C23 <stdbit.h> 2024-01-03 12:07:14 +00:00
stdc-predef.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
stdint.h Move inttypes.h and stdint.h to stdlib. 2019-03-13 09:42:09 -04:00
stdio_ext.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
stdio.h stdio: Remove __libc_message alloca usage 2023-09-11 16:16:49 +00:00
stdlib.h stdlib: Remove use of mergesort on qsort (BZ 21719) 2023-10-31 14:18:05 -03:00
string.h chk: Add and fix hidden builtin definitions for *_chk 2023-08-03 22:46:48 +02:00
strings.h
struct___timeb64.h time: Add 64-bit time_t support for ftime 2020-10-27 09:54:50 -03:00
struct___timespec64.h y2038: include: Move struct __timespec64 definition to a separate file 2020-04-06 23:05:11 +02:00
struct___timeval64.h y2038: include: Move struct __timeval64 definition to a separate file 2020-05-05 19:36:25 +02:00
stubs-prologue.h * sysdeps/generic/bits/libc-tsd.h [USE___THREAD]: Conditional 2002-10-11 10:52:20 +00:00
syscall.h
sysexits.h
syslog.h
tar.h
termios.h Hide internal __tcgetattr function [BZ #18822] 2017-10-01 17:48:24 -07:00
tgmath.h
time.h Define in_int32_t_range to check if the 64 bit time_t syscall should be used 2022-11-17 14:35:13 -03:00
ttyent.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
uchar.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
ucontext.h Update. 1999-10-12 18:17:41 +00:00
ulimit.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
unistd_ext.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
unistd.h unistd: Avoid PLT entries with _FORTIFY_SOURCE 2023-07-05 16:59:48 +02:00
utime.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
utmp.h login: Move libutil into libc 2021-06-30 08:43:37 +02:00
values.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
verify.h posix: Sync regex with gnulib 2019-11-06 09:20:52 -03:00
wait.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
wchar.h wchar: Avoid PLT entries with _FORTIFY_SOURCE 2023-07-05 16:59:48 +02:00
wctype.h Remove __need macros from stdio.h and wchar.h. 2017-06-08 13:58:17 -04:00
wordexp.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00