clang might generate an abort call when cleanup functions (set by
__attribute__ ((cleanup)) calls functions not marked as nothrow.
We can mitigate by marking some internal functions as __THROW,
but it is not possible for functions that issue used-provided
callbacks (for instance pthread_once).
The pointer alias comparison will be optimized away by the compiler,
and gcc and clang will evaluate differently (clang evaluates as
false, while gcc as true).
clang does not handle pseudo normal numbers, so disable the fpclassify
and isnormal builtin optimization if clang is used. This only affect
x86, so add a new header, fp-builtin-denormal.h, which defines whether
the architecture required to disable the optimization through a new
glibc define (__FP_BUILTIN_DENORMAL).
It fixes the regression on test-ldouble-fpclassify and test-float64x-fpclassify
when built with clang:
Failure: fpclassify (pseudo_zero): Exception "Invalid operation" set
Failure: fpclassify (pseudo_inf): Exception "Invalid operation" set
Failure: fpclassify (pseudo_qnan): Exception "Invalid operation" set
Failure: fpclassify (pseudo_snan): Exception "Invalid operation" set
Failure: fpclassify (pseudo_unnormal): Exception "Invalid operation" set
Failure: fpclassify_downward (pseudo_zero): Exception "Invalid operation" set
Failure: fpclassify_downward (pseudo_inf): Exception "Invalid operation" set
Failure: fpclassify_downward (pseudo_qnan): Exception "Invalid operation" set
Failure: fpclassify_downward (pseudo_snan): Exception "Invalid operation" set
Failure: fpclassify_downward (pseudo_unnormal): Exception "Invalid operation" set
Failure: fpclassify_towardzero (pseudo_zero): Exception "Invalid operation" set
Failure: fpclassify_towardzero (pseudo_inf): Exception "Invalid operation" set
Failure: fpclassify_towardzero (pseudo_qnan): Exception "Invalid operation" set
Failure: fpclassify_towardzero (pseudo_snan): Exception "Invalid operation" set
Failure: fpclassify_towardzero (pseudo_unnormal): Exception "Invalid operation" set
Failure: fpclassify_upward (pseudo_zero): Exception "Invalid operation" set
Failure: fpclassify_upward (pseudo_inf): Exception "Invalid operation" set
Failure: fpclassify_upward (pseudo_qnan): Exception "Invalid operation" set
Failure: fpclassify_upward (pseudo_snan): Exception "Invalid operation" set
Failure: fpclassify_upward (pseudo_unnormal): Exception "Invalid operation" set
clang generates internal calls for some _chk symbol, so add internal
aliases for them, and stub some with rtld-stubbed-symbols to avoid
ld.so linker issues.
riscv: Suppress clang -Wignored-attributes for feupdateenv
clang warns that the alias will be always resolve to
__GI___feupdateenv even if weak definition of __GI_feupdateenv
is overridden, which is really the intention.
Recent clang version optimizes some loops contructions to strlen [1],
which might generate function calls when self-relocation is not
already done (on tunable parsing). Use an out-of-line function
with __attribute_optimization_barrier__ to avoid this.
Check if linker sets --no-undefined-version by default
Recent lld version default to --no-undefined-version, which triggers
errors when building multiple libraries. For ld.so it fails with:
ld.lld: error: version script assignment of 'GLIBC_2.4' to symbol '__stack_chk_guard' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_PRIVATE' to symbol '__nptl_set_robust_list_avail' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_PRIVATE' to symbol '__pointer_chk_guard' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_PRIVATE' to symbol '_dl_starting_up' failed: symbol not defined
While for libc.so:
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_clearerr' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_fgetc' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_fileno' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_freopen' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_fscanf' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_fseek' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_peekc_unlocked' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_stderr_' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_stdin_' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_stdout_' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_pclose' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_perror' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_rewind' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_scanf' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_setbuf' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_setlinebuf' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_wdefault_setbuf' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '_IO_wfile_setbuf' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '__ctype32_tolower' failed: symbol not defined
ld.lld: error: version script assignment of 'GLIBC_2.17' to symbol '__ctype32_toupper' failed: symbol not defined
ld.lld: error: too many errors emitted, stopping now (use --error-limit=0 to see all errors)
The way version script is created with multiple missing symbols is
to simplify the build for multiple ABIs with different symbol
symbols. For instance, __stack_chk_guard is defined by default to
avoid the need of each ABI to add this symbol on its own version
script depending of which stack protector ABI it uses.
The libc.so warnings does show unused symbol being defined (like
_IO_clearerr), which might trigger potential errors depending of
how symbol are exported. However, since we do have teh ABI checks
for missing and extra symbol the linker extra checks are not really
required. So disable them for now.
Supress unused command arguments warning with clang
clang 20 triggers an error for the unused '-c' argument used to create
errlist-data-aux-shared.S, errlist-data-aux.S, siglist-aux-shared.S,
and siglist-aux.S.
GCC enables it by default, clang in the other hand sets -fno-trapping-math.
This is required to fix some math and stdlib tests that explicit raises
floating point exceptions:
math/test-double-canonicalize.out
testing double (without inline functions)
Failure: canonicalize (max_value): Exception "Overflow" set
Failure: canonicalize (max_value): Exception "Inexact" set
Failure: canonicalize (-max_value): Exception "Overflow" set
Failure: canonicalize (-max_value): Exception "Inexact" set
Failure: canonicalize_downward (max_value): Exception "Overflow" set
Failure: canonicalize_downward (max_value): Exception "Inexact" set
Failure: canonicalize_downward (-max_value): Exception "Overflow" set
Failure: canonicalize_downward (-max_value): Exception "Inexact" set
Failure: canonicalize_towardzero (max_value): Exception "Overflow" set
Failure: canonicalize_towardzero (max_value): Exception "Inexact" set
Failure: canonicalize_towardzero (-max_value): Exception "Overflow" set
Failure: canonicalize_towardzero (-max_value): Exception "Inexact" set
Failure: canonicalize_upward (max_value): Exception "Overflow" set
Failure: canonicalize_upward (max_value): Exception "Inexact" set
Failure: canonicalize_upward (-max_value): Exception "Overflow" set
Failure: canonicalize_upward (-max_value): Exception "Inexact" set
test-float-catanh.out
testing float (without inline functions)
Failure: Real part of: catanh (-0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh (-0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh (-0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh (-0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh (-0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh (-0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh (0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh (0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh (0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh (0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh (0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh (0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (-0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (-0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (-0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (-0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (-0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (-0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_downward (0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (-0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (-0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (-0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (-0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (-0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (-0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_towardzero (0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (-0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (-0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (-0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (-0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (-0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (-0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (0x1.000002p+0 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (0x1.000002p+0 - 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (0x1.000002p+0 + 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (0x1.000002p+0 + 0x8p-152 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (0xf.fffffp-4 - 0x4p-128 i): Exception "Underflow" set
Failure: Real part of: catanh_upward (0xf.fffffp-4 + 0x4p-128 i): Exception "Underflow" set
Add fall-through between switch labels annotations
The clang default to warning for missing fall-through and it does
not support all comment-like annotation that gcc does. Use a
proper attribute instead.
And although NAME_IFUNC is and alias for NAME, clang still emits
an 'unused function 'name_ifunc' [-Werror,-Wunused-function]'
warning. The static is used to avoid name pollution on static
linkage.
x86: Use __always_inline on ifunc auxiliary functions
clang does correctly propagate the no_stack_protector attribute for
inline function used in ifunc selectors. For instance, the exp function
is expanded as:
The ifunc selection ended being compiled with -fstack-protector, and
with debug function set to the ifunc selector
(ieee754_exp_ifunc_selector) auxiliary function instead of the
selector itself.
The ifunc selector are called early, before TCB is setup, which
causes SIGSEGV for statically linked binaries.
To fix it use __always_inline instead of inline. It should not change
code generation on gcc and it fixes the code generation issue on
clang. It also fixes function debug information.
clang-19 does support it, but it should be gated as an option to
assemble (either with -Wa or -Xassembler). So add a test for -Wa
as well if -msse2avx is not supported.
stdio: Fix -Wtautological-constant-out-of-range-compare on clang
clang emits an error while building vfprintf-internal for default
case:
error: result of comparison of constant 255 with expression of type
'char' is always true
[-Werror,-Wtautological-constant-out-of-range-compare]
if (spec <= UCHAR_MAX
The test is indeed not required for default non-wide build.
On ABIs with defined 'char' was unsigned type, clang fails to build
support_process_state.c with:
support_process_state.c:70:21: error: result of comparison of constant -1 with expression of type 'char' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
70 | if (cur_state == -1)
| ~~~~~~~~~ ^ ~~
1 error generated.
The constant should be used with c_cc, which for all supported ABIs
is defined as unsigned char. By using it as literar char constant,
clang triggers an error when compared with signal literal o ABIs that
define 'char' as unsigned.
On aarch64, clang shows:
../sysdeps/posix/fpathconf.c:118:21: error: right side of operator
converted from negative value to unsigned: -1 to 18446744073709551615
[-Werror]
#if _POSIX_VDISABLE == -1
~~~~~~~~~~~~~~~ ^ ~~
Use $(config-cflags-wno-ignored-attributes) on some files
clang emits an warning when a double alias redirection is used, to warn
the the original symbol will be used even when weak definition is
overridden. Howerver, this is a common pattern for weak_alias, where
multiple alias are set to same symbol.
math: Suppress clang -Wincompatible-library-redeclaration on s_llround
Clang issues:
../sysdeps/ieee754/dbl-64/s_llround.c:83:30: error: incompatible
redeclaration of library function 'lround'
[-Werror,-Wincompatible-library-redeclaration]
libm_alias_double (__lround, lround)
^
../sysdeps/ieee754/dbl-64/s_llround.c:83:30: note: 'lround' is a builtin
with type 'long (double)'
math: Suppress clang warning on math_check_force_underflow
clang warns:
../sysdeps/x86/fpu/powl_helper.c:233:3: error: absolute value function
'__builtin_fabsf' given an argument of type 'typeof (res)' (aka 'long
double') but has parameter of type 'float' which may cause truncation of
value [-Werror,-Wabsolute-value]
math_check_force_underflow (res);
^
./math-underflow.h:45:11: note: expanded from macro
'math_check_force_underflow'
if (fabs_tg (force_underflow_tmp) \
^
./math-underflow.h:27:20: note: expanded from macro 'fabs_tg'
#define fabs_tg(x) __MATH_TG ((x), (__typeof (x)) __builtin_fabs, (x))
^
../math/math.h:899:16: note: expanded from macro '__MATH_TG'
float: FUNC ## f ARGS, \
^
<scratch space>:73:1: note: expanded from here
__builtin_fabsf
^
It simplifies the code a bit and avoid the clang warning:
./config.h:12:2: error: #include_next in file found relative to primary
source file or found by absolute path; will search from start of include
path [-Werror,-Winclude-next-absolute-path]
#include_next <config.h>
^
programs/ld-collate.c:1824:55: error: implicit conversion from 'unsigned
long' to 'unsigned int' changes value from 18446744073709551615 to 4294967295 [-Werror,-Wconstant-conversion]
collate->undefined.used_in_level = need_undefined ? ~0ul : 0;
~ ^~~~
elf: Supress clang -Wsometimes-uninitialized on _dl_debug_initialize
clang issues an warning where variable 'r' is used uninitialized
whenever 'if' condition is false. The _dl_debug_initialize is called
for static case always with LM_ID_BASE (csu/libc-start.c and
elf/dl-reloc-static-pie.c) and DL_NSS will be always larger than 1
for shared case.
clang complains if a flexible array member (struct cmsghdr) is not a
the end of the struct (since it is a GNU extension). The __msgread
explicit expects that 'struct ucred' is after the 'cmsg', so suppress
the warning.
clang issues a 'equality comparison with extraneous parentheses
[-Werror,-Wparentheses-equality]' in this. Instead of suppress
the warning, just use the more usual comparison style.
argp: Expand argp_usage, _option_is_short, and _option_is_end
The argp code uses some clever macro redefine to avoid need to
duplicate the optimized static inline implementations for
argp_usage, _option_is_short, and _option_is_end. This however
leads to some build issues with clang, since some function
prototypes are redefined to add the hidden attribute with
libc_hidden_proto.
To avoid extensive changes on internal headers, just expand the
function implementations and avoid the macro redefine tricks.
clang does not allow to redefine attributes after function declaration.
Although it work for external usage, its breaks the build for internal
symbol that glibc provides as optimization (for instance bsearch
with stdlib-bsearch.h or __cmsg_nxthdr).
Disable such optimization for clang while building glibc.
stdlib: longlong.h: Do no use asm input cast for clang
clang by default rejects the input casts with:
error: invalid use of a cast in a inline asm context requiring an
lvalue: remove the cast or build with -fheinous-gnu-extensions
And even with -fheinous-gnu-extensions clang still throws an warning
and also states that this option might be removed in the future.
For gcc the cast are still useful [1] as type-checking.
elf: Extend glibc.rtld.execstack tunable to force executable stack (BZ 32653)
From the bug report [1], multiple programs still require to dlopen
shared libraries with either missing PT_GNU_STACK or with the executable
bit set. Although, in some cases, it seems to be a hard-craft assembly
source without the required .note.GNU-stack marking (so the static linker
is forced to set the stack executable if the ABI requires it), other
cases seem that the library uses trampolines [2].
Unfortunately, READ_IMPLIES_EXEC is not an option since on some ABIs
(x86_64), the kernel clears the bit, making it unsupported. To avoid
reinstating the broken code that changes stack permission on dlopen
(0ca8785a28), this patch extends the glibc.rtld.execstack tunable to
allow an option to force an executable stack at the program startup.
The tunable is a security issue because it defeats the PT_GNU_STACK
hardening. It has the slight advantage of making it explicit by the
caller, and, as for other tunables, this is disabled for setuid binaries.
A tunable also allows us to eventually remove it, but from previous
experiences, it would require some time.
Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=32653
[2] https://github.com/conda-forge/ctng-compiler-activation-feedstock/issues/143 Reviewed-by: Sam James <sam@gentoo.org>
stdio-common: In tst-setvbuf2, close helper thread descriptor only if opened
The helper thread may get canceled before the open system
call succeds. Then ThreadData.fd remains zero, and eventually
the xclose call in end_reader_thread fails because descriptor 0
is not open.
Instead, initialize the fd member to -1 (not a valid descriptor)
and close the descriptor only if valid. Do this in a new end_thread
helper routine.
Scan xstate IDs up to the maximum supported xstate ID. Remove the
separate AMX xstate calculation. Instead, exclude the AMX space from
the start of TILECFG to the end of TILEDATA in xsave_state_size.
Completed validation on SKL/SKX/SPR/SDE and compared xsave state size
with "ld.so --list-diagnostics" option, no regression.
Co-Authored-By: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
stdlib: Fix qsort memory leak if callback throws (BZ 32058)
If the input buffer exceeds the stack auxiliary buffer, qsort will
malloc a temporary one to call mergesort. Since C++ standard does
allow the callback comparison function to throw [1], the glibc
implementation can potentially leak memory.
The fixes uses a pthread_cleanup_combined_push and
pthread_cleanup_combined_pop, so it can work with and without
exception enables. The qsort code path that calls malloc now
requires some extra setup and a call to __pthread_cleanup_push
anmd __pthread_cleanup_pop (which should be ok since they just
setup some buffer state).
Support older versions of GCC to build glibc 2.42:
1. Need to work around bugs in older versions of GCC.
2. Can't use the new features in newer versions of GCC, which may be
required for new features, like _Float16 which requires GCC 12.1 or
above, in glibc,
The main benefit of supporting older versions of GCC is easier backport
of bug fixes to the older releases of glibc, which can be mitigated by
avoiding incompatible features in newer versions of GCC for critical bug
fixes. Require GCC 12.1 or newer to build. Remove GCC version check for
PowerPC and s390x.
TEST_CC and TEST_CXX can be used to test the glibc build with the older
versions of GCC.
For glibc developers who are using Linux OSes which don't come with GCC
12.1 or newer, they should build and install GCC 12.1 or newer to work
on glibc.
This fixes BZ #32539.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Sam James <sam@gentoo.org>
Collin Funk [Thu, 27 Mar 2025 06:36:30 +0000 (23:36 -0700)]
manual: Document functions adopted by POSIX.1-2024.
Here is a patch updating the documentation to mention GNU and BSD
extensions that were adopted by POSIX.1-2024.
* manual/llio.texi (Memory-mapped I/O): Add that MAP_ANON and
MAP_ANONYMOUS were added by POSIX.1-2024.
* manual/memory.texi (Changing Block Size): Mention that reallocarray
was added by POSIX.1-2024.
* manual/message.texi (Message Translation): Adjust wording to match
standardization.
(Translation with gettext): Mention the gettext family of functions were
added by POSIX.1-2024.
* manual/pattern.texi (Wildcard Matching): Mention that FNM_CASEFOLD was
added by POSIX.1-2024.
* manual/process.texi (Creating a Process): Mention that _Fork and
WCOREDUMP were added by POSIX.1-2024.
* manual/signal.texi (Miscellaneous Signals): Mention that SIGWINCH was
added by POSIX-1.2024.
* manual/startup.texi (Environment Access): Mention that secure_getenv
was added by POSIX.1-2024.
* manual/string.texi (Truncating Strings): Mention that strlcpy,
strlcat, wcslcpy, and wslcat were added by POSIX-1.2024.
(Search Functions): Document that memmem was added by POSIX-1.2024.
* manual/terminal.texi (Allocation): Mention that ptsname_r was added by
POSIX-1.2024.
* manual/threads.texi (Waiting with Explicit Clocks): Move node under
POSIX Threads. Mention pthread_cond_clockwait,
pthread_rwlock_clockrdlock, and pthread_rwlock_clockwrlock were added by
POSIX-1.2024.
(Joining Threads): New node under Non-POSIX Extensions.
aarch64: Fix _dl_tlsdesc_dynamic unwind for pac-ret (BZ 32612)
When libgcc is built with pac-ret, it requires to autenticate the
unwinding frame based on CFI information. The _dl_tlsdesc_dynamic
uses a custom calling convention, where it is responsible to save
and restore all registers it might use (even volatile).
The pac-ret support added by 1be3d6eb823d8b952fa54b7bbc90cbecb8981380
was added only on the slow-path, but the fast path also adds DWARF
Register Rule Instruction (cfi_adjust_cfa_offset) since it requires
to save/restore some auxiliary register. It seems that this is not
fully supported neither by libgcc nor AArch64 ABI [1].
Instead, move paciasp/autiasp to function prologue/epilogue to be
used on both fast and slow paths.
I also corrected the _dl_tlsdesc_dynamic comment description, it was
copied from i386 implementation without any adjustment.
Checked on aarch64-linux-gnu with a toolchain built with
--enable-standard-branch-protection on a system with pac-ret
support.
Florian Weimer [Fri, 28 Mar 2025 08:26:59 +0000 (09:26 +0100)]
x86: Use separate variable for TLSDESC XSAVE/XSAVEC state size (bug 32810)
Previously, the initialization code reused the xsave_state_full_size
member of struct cpu_features for the TLSDESC state size. However,
the tunable processing code assumes that this member has the
original XSAVE (non-compact) state size, so that it can use its
value if XSAVEC is disabled via tunable.
This change uses a separate variable and not a struct member because
the value is only needed in ld.so and the static libc, but not in
libc.so. As a result, struct cpu_features layout does not change,
helping a future backport of this change.
Florian Weimer [Fri, 28 Mar 2025 08:26:06 +0000 (09:26 +0100)]
x86: Skip XSAVE state size reset if ISA level requires XSAVE
If we have to use XSAVE or XSAVEC trampolines, do not adjust the size
information they need. Technically, it is an operator error to try to
run with -XSAVE,-XSAVEC on such builds, but this change here disables
some unnecessary code with higher ISA levels and simplifies testing.
Wilco Dijkstra [Thu, 20 Mar 2025 20:04:14 +0000 (20:04 +0000)]
malloc: Improve performance of __libc_malloc
Improve performance of __libc_malloc by splitting it into 2 parts: first handle
the tcache fastpath, then do the rest in a separate tailcalled function.
This results in significant performance gains since __libc_malloc doesn't need
to setup a frame and we delay tcache initialization and setting of errno until
later.
On Neoverse V2, bench-malloc-simple improves by 6.7% overall (up to 8.5% for
ST case) and bench-malloc-thread improves by 20.3% for 1 thread and 14.4% for
32 threads.
stdio-common: Reject real data w/o exponent digits in scanf [BZ #12701]
Reject invalid formatted scanf real input data the exponent part of
which is comprised of an exponent introducing character, optionally
followed by a sign, and with no actual digits following. Such data is a
prefix of, but not a matching input sequence and it is required by ISO C
to cause a matching failure.
Currently a matching success is instead incorrectly produced along with
the conversion result according to the input significand read and the
exponent of zero, with the significand and the exponent part wholly
consumed from input.
Correct an invalid `tstscanf.c' test accordingly that expects a matching
success for input data provided in the ISO C standard as an example for
a matching failure.
Enable input data that causes test failures without this fix in place.
stdio-common: Reject significand prefixes in scanf [BZ #12701]
Reject invalid formatted scanf real input data that is comprised of a
hexadecimal prefix, optionally preceded by a sign, and with no actual
digits following owing to the field width restriction in effect. Such
data is a prefix of, but not a matching input sequence and it is
required by ISO C to cause a matching failure.
Currently a matching success is instead incorrectly produced along with
the conversion result of zero, with the prefix wholly consumed from
input. Where the end of input is marked by the end-of-file condition
rather than the field width restriction in effect a matching failure is
already correctly produced.
Enable input data that causes test failures without this fix in place.
stdio-common: Reject integer prefixes in scanf [BZ #12701]
Reject invalid formatted scanf integer input data that is comprised of a
binary or hexadecimal prefix, optionally preceded by a sign, and with no
actual digits following. Such data is a prefix of, but not a matching
input sequence and it is required by ISO C to cause a matching failure.
Currently a matching success is instead incorrectly produced along with
the conversion result of zero, with the prefix wholly consumed from
input.
Enable input data that causes test failures without this fix in place.
stdio-common: Also reject exp char w/o significand in i18n scanf [BZ #13988]
Fix the handling of real 'scanf' input such as "+.e" as per BZ #13988
for the i18n case as well, complementing commit 6ecec3b616ae ("Don't
accept exp char without preceding digits in scanf float parsing"), where
the 'e' character is incorrectly consumed from input. Add a test case
matching stdio-common/bug26.c, with bits from localedata/tst-sscanf.c.
stdio-common: Add scanf long double data for Intel/Motorola 80-bit format
Add Makefile infrastructure, a format-specific test skeleton providing a
data comparison implementation that ignores bits of data representation
in memory that do not participate in holding floating-point data, and
`long double' real input data for targets using the Intel/Motorola
80-bit format.
Keep input data disabled and referring to BZ #12701 for entries that are
are currently incorrectly accepted as valid data, such as '0e', '0e+',
'0x', '0x8p', '0x0p-', etc.
Joseph Myers [Thu, 27 Mar 2025 10:44:44 +0000 (10:44 +0000)]
Implement C23 pown
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the pown functions, which are like pow but with an
integer exponent. That exponent has type long long int in C23; it was
intmax_t in TS 18661-4, and as with other interfaces changed after
their initial appearance in the TS, I don't think we need to support
the original version of the interface. The test inputs are based on
the subset of test inputs for pow that use integer exponents that fit
in long long.
As the first such template implementation that saves and restores the
rounding mode internally (to avoid possible issues with directed
rounding and intermediate overflows or underflows in the wrong
rounding mode), support also needed to be added for using
SET_RESTORE_ROUND* in such template function implementations. This
required math-type-macros-float128.h to include <fenv_private.h>, so
it can tell whether SET_RESTORE_ROUNDF128 is defined. In turn, the
include order with <fenv_private.h> included before <math_private.h>
broke loongarch builds, showing up that
sysdeps/loongarch/math_private.h is really a fenv_private.h file
(maybe implemented internally before the consistent split of those
headers in 2018?) and needed to be renamed to fenv_private.h to avoid
errors with duplicate macro definitions if <math_private.h> is
included after <fenv_private.h>.
The underlying implementation uses __ieee754_pow functions (called
more than once in some cases, where the exponent does not fit in the
floating type). I expect a custom implementation for a given format,
that only handles integer exponents but handles larger exponents
directly, could be faster and more accurate in some cases.
I encourage searching for worst cases for ulps error for these
implementations (necessarily non-exhaustively, given the size of the
input space).
Tested for x86_64 and x86, and with build-many-glibcs.py.
Florian Weimer [Wed, 26 Mar 2025 16:46:40 +0000 (17:46 +0100)]
support: Use unwinder in links-dso-program-c only with libgcc_s
Do not build links-dso-program-c with exception (unwinding) support
if libgcc_s is not available. In this case, the unwinder may be
part of libgcc.a or libgcc_eh.a, depending on how GCC was built.
If the unwinder is in libgcc_eh.a only, linking links-dso-program-c
failed before this change. After this change, the exception
handling landing pad is only generated if libgcc_s available,
avoiding an undefined _Unwind_Resume (or equivalent) symbol
reference in the non-libgcc_s case.
projects / thirdparty / glibc.git / log
