According to the specification of ISO/IEC TS 18661-1:2014,
The strfromd, strfromf, and strfroml functions are equivalent to
snprintf(s, n, format, fp) (7.21.6.5), except the format string contains only
the character %, an optional precision that does not contain an asterisk *, and
one of the conversion specifiers a, A, e, E, f, F, g, or G, which applies to
the type (double, float, or long double) indicated by the function suffix
(rather than by a length modifier). Use of these functions with any other 20
format string results in undefined behavior.
strfromf will convert the arguement with type float to double first.
According to the latest version of IEEE754 which is published in 2019,
Conversion of a quiet NaN from a narrower format to a wider format in the same
radix, and then back to the same narrower format, should not change the quiet
NaN payload in any way except to make it canonical.
When either an input or result is a NaN, this standard does not interpret the
sign of a NaN. However, operations on bit strings—copy, negate, abs,
copySign—specify the sign bit of a NaN result, sometimes based upon the sign
bit of a NaN operand. The logical predicates totalOrder and isSignMinus are
also affected by the sign bit of a NaN operand. For all other operations, this
standard does not specify the sign bit of a NaN result, even when there is only
one input NaN, or when the NaN is produced from an invalid operation.
converting NAN or -NAN with type float to double doesn't need to keep
the signbit. As a result, this test case isn't mandatory.
The problem is that according to RISC-V ISA manual in chapter 11.3 of
riscv-isa-20191213,
Except when otherwise stated, if the result of a floating-point operation is
NaN, it is the canonical NaN. The canonical NaN has a positive sign and all
significand bits clear except the MSB, a.k.a. the quiet bit. For
single-precision floating-point, this corresponds to the pattern 0x7fc00000.
which means that conversion -NAN from float to double won't keep the signbit.
Since glibc ought to be consistent here between types and architectures, this
patch adds copysign to fix this problem if the string is NAN. This patch
adds two different functions under sysdeps directory to work around the
issue.
This patch has been tested on x86_64 and riscv64.
Resolves: BZ #29501
v2: Change from macros to different inline functions.
v3: Add unlikely check to isnan.
v4: Fix wrong commit message header.
v5: Fix style: add space before parentheses.
v6: Add copyright.
Signed-off-by: Letu Ren <fantasquex@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
ulimit is a variadic function and the second argument must have type
long (or unsigned long).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
sscanf is only defined on nul terminated string input, but '\0' was
missing in this test which caused _IO_str_init_static_internal to
read OOB on the stack when computing the bounds of the string.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
The alloca size did not consider the optional width parameter for
padding which could cause buffer underflow. The width is currently used
e.g. by _dl_map_object_from_fd which passes 2 * sizeof(void *) which
can be larger than the alloca buffer size on targets where
sizeof(void *) >= 2 * sizeof(unsigned long).
Even if large width is not used on existing targets it is better to fix
the formatting code to avoid surprises.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
The extension header is two 32bit words and in the last header both
should be 0. There is plenty space in the __reserved area, but it's
better not to write more than we mean to.
Use an empty wordcopy.c to avoid building the generic one.
It does not seem to be used anywhere.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The initializer for a tunable_t set the bool initialized flag to NULL.
This causes a build failure when pointer to bool conversion warns.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
This consolidates the destructor invocations from _dl_fini and
dlclose. Remove the micro-optimization that avoids
calling _dl_call_fini if they are no destructors (as dlclose is quite
expensive anyway). The debug log message is now printed
unconditionally.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This allows the rest of dynamic loader to check whether the TCB
has been set up (and THREAD_GETMEM and THREAD_SETMEM will work).
Reviewed-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
On csky-linux-gnuabiv2, binutils 2.33 produces a DT_JMPREL entry
for the dynamic loader if it does not contain any PLT relocations:
Dynamic section at offset 0x1df48 contains 19 entries:
Tag Type Name/Value
0x0000000e (SONAME) Library soname: [ld-linux-cskyv2-hf.so.1]
0x00000004 (HASH) 0xd4
0x6ffffef5 (GNU_HASH) 0x1a8
0x00000005 (STRTAB) 0x4ac
0x00000006 (SYMTAB) 0x28c
0x0000000a (STRSZ) 527 (bytes)
0x0000000b (SYMENT) 16 (bytes)
0x00000003 (PLTGOT) 0x1f000
0x00000002 (PLTRELSZ) 0 (bytes)
0x00000014 (PLTREL) RELA
0x00000017 (JMPREL) 0xaa4
0x00000007 (RELA) 0x75c
0x00000008 (RELASZ) 840 (bytes)
0x00000009 (RELAENT) 12 (bytes)
0x6ffffffc (VERDEF) 0x700
0x6ffffffd (VERDEFNUM) 3
0x6ffffff0 (VERSYM) 0x6bc
0x6ffffff9 (RELACOUNT) 68
0x00000000 (NULL) 0x0
This confuses the script:
Unexpected output from check-localplt: …/elf/ld.so.jmprel:
*** DT_JMPREL does not match any section's address
This commit changes the script to record the DT_PLTRELSZ value and
reject DT_JMPREL values not a section boundary only if DT_PLTRELSZ
is present with a non-zero value.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Since __memcpy_simd is the fastest memcpy on almost all cores, replace
the generic memcpy with it. If SVE is available, a SVE memcpy will be
used by default (including for Neoverse N2).
This patch implements following evex512 version of string functions.
evex512 version takes up to 30% less cycle as compared to evex,
depending on length and alignment.
- strchrnul function using 512 bit vectors.
- strchr function using 512 bit vectors.
- wcschr function using 512 bit vectors.
Code size data:
strchrnul-evex.o 599 byte
strchrnul-evex512.o 569 byte (-5%)
strchr-evex.o 639 byte
strchr-evex512.o 595 byte (-7%)
wcschr-evex.o 644 byte
wcschr-evex512.o 607 byte (-6%)
Placeholder function, not used by any processor at the moment.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The generic Linux struct_stat misses the conditionals to use
bits/struct_stat_time64_helper.h in the __USE_TIME_BITS64 for
architecture that uses __TIMESIZE == 32 (currently csky and nios2).
Since newer ports should not support 32 bit time_t, the generic
implementation should be used as default.
For arm, hppa, and sh a copy of default struct_stat is added,
while for csky and nios a new one based on generic is used, along
with conditionals to use bits/struct_stat_time64_helper.h.
The default struct_stat is also replaced with the generic one.
Checked on aarch64-linux-gnu and arm-linux-gnueabihf.
Detecting an overflow edge case depended on signed overflow of a long
long. Replace the additions and the overflow checks by
__builtin_add_overflow().
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
The builtin bswap is already used if optimziation is enabled for
GCC 4.8+, so glibc symbols will be used in a very limited scenarios.
Also, gcc generated code is quite similar to all but ia64 and i386
htons.
Checked on alpha, i686, and ia64.
Generic implementation on top of __bswap_32 always expands
inline to either bswap or movbe depending on -march=*.
Signed-off-by: Cristian Rodríguez <crrodriguez@opensuse.org>
Avoid moving code across SET_RESTORE_ROUNDL in order to fix
[BZ #29463].
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Linux 6.0 adds a constant ADDRB, a termios c_cflag bit, to its
include/uapi/asm-generic/termbits-common.h.
Add it accordingly to glibc's bits/termios-c_cflag.h headers. As
other constants in these headers are generally in octal, I converted
the value to octal to match. As ADDRB isn't in a POSIX-reserved
namespace, I made it conditional on __USE_MISC.
Tested for x86_64.
Unused at the moment, but evex512 strcmp, strncmp, strcasecmp{l}, and
strncasecmp{l} functions can be added by including strcmp-evex.S with
"x86-evex512-vecs.h" defined.
In addition save code size a bit in a few places.
1. tzcnt ... -> bsf ...
2. vpcmp{b|d} $0 ... -> vpcmpeq{b|d}
This saves a touch of code size but has minimal net affect.
Full check passes on x86-64.
commit b412213eee
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date: Tue Oct 18 17:44:07 2022 -0700
x86: Optimize strrchr-evex.S and implement with VMM headers
Added `vpcompress{b|d}` to the page-cross logic with is an
AVX512-VBMI2 instruction. This is not supported on SKX. Since the
page-cross logic is relatively cold and the benefit is minimal
revert the page-cross case back to the old logic which is supported
on SKX.
Tested on x86-64.
The ARM preconfigure script tries to detect the capabilities of the
target platform by checking the compiler's predefined architecture
macros. However, if the compiler is tuning for AArch32 on ARMv8/v9 this
step fails:
checking for sysdeps preconfigure fragments... aarch64 alpha arc arm
WARNING: arm/preconfigure: Did not find ARM architecture type; using default
This is because preconfigure.ac doesn't escape the square brackets in
the glob for matching compilers targeting ARMv8. Adding another pair of
brackets to escape the first pair fixes this:
checking for sysdeps preconfigure fragments... aarch64 alpha arc arm
Found compiler is configured for something newer than v7 - using v7
Signed-off-by: Felix Riemann <felix.riemann@sma.de>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Remove implicit conversion from enumeration type 'zotypes' to different
type 'nstype'.
Checked on x86_64-linux-gnu.
Reviewed-by: Arjun Shankar <arjun@redhat.com>
The current macros uses pid as signed value, which triggers a compiler
warning for process and thread timers. Replace MAKE_PROCESS_CPUCLOCK
with static inline function that expects the pid as unsigned. These
are similar to what Linux does internally.
Checked on x86_64-linux-gnu.
Reviewed-by: Arjun Shankar <arjun@redhat.com>
Optimization is:
1. Cache latest result in "fast path" loop with `vmovdqu` instead of
`kunpckdq`. This helps if there are more than one matches.
Code Size Changes:
strrchr-evex.S : +30 bytes (Same number of cache lines)
Net perf changes:
Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.
strrchr-evex.S : 0.932 (From cases with higher match frequency)
Full results attached in email.
Full check passes on x86-64.
Optimizations are:
1. Use the fact that lzcnt(0) -> VEC_SIZE for memchr to save a branch
in short string case.
2. Save several instructions in len = [VEC_SIZE, 4 * VEC_SIZE] case.
3. Use more code-size efficient instructions.
- tzcnt ... -> bsf ...
- vpcmpb $0 ... -> vpcmpeq ...
Code Size Changes:
memrchr-evex.S : -29 bytes
Net perf changes:
Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.
memrchr-evex.S : 0.949 (Mostly from improvements in small strings)
Full results attached in email.
Full check passes on x86-64.
Optimizations are:
1. Use the fact that bsf(0) leaves the destination unchanged to save a
branch in short string case.
2. Restructure code so that small strings are given the hot path.
- This is a net-zero on the benchmark suite but in general makes
sense as smaller sizes are far more common.
3. Use more code-size efficient instructions.
- tzcnt ... -> bsf ...
- vpcmpb $0 ... -> vpcmpeq ...
4. Align labels less aggressively, especially if it doesn't save fetch
blocks / causes the basic-block to span extra cache-lines.
The optimizations (especially for point 2) make the strnlen and
strlen code essentially incompatible so split strnlen-evex
to a new file.
Code Size Changes:
strlen-evex.S : -23 bytes
strnlen-evex.S : -167 bytes
Net perf changes:
Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.
strlen-evex.S : 0.992 (No real change)
strnlen-evex.S : 0.947
Full results attached in email.
Full check passes on x86-64.
Size Optimizations:
1. Condence hot path for better cache-locality.
- This is most impact for strchrnul where the logic strings with
len <= VEC_SIZE or with a match in the first VEC no fits entirely
in the first cache line.
2. Reuse common targets in first 4x VEC and after the loop.
3. Don't align targets so aggressively if it doesn't change the number
of fetch blocks it will require and put more care in avoiding the
case where targets unnecessarily split cache lines.
4. Align the loop better for DSB/LSD
5. Use more code-size efficient instructions.
- tzcnt ... -> bsf ...
- vpcmpb $0 ... -> vpcmpeq ...
6. Align labels less aggressively, especially if it doesn't save fetch
blocks / causes the basic-block to span extra cache-lines.
Code Size Changes:
strchr-evex.S : -63 bytes
strchrnul-evex.S: -48 bytes
Net perf changes:
Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.
strchr-evex.S (Fixed) : 0.971
strchr-evex.S (Rand) : 0.932
strchrnul-evex.S : 0.965
Full results attached in email.
Full check passes on x86-64.
Optimizations are:
1. Use the fact that tzcnt(0) -> VEC_SIZE for memchr to save a branch
in short string case.
2. Restructure code so that small strings are given the hot path.
- This is a net-zero on the benchmark suite but in general makes
sense as smaller sizes are far more common.
3. Use more code-size efficient instructions.
- tzcnt ... -> bsf ...
- vpcmpb $0 ... -> vpcmpeq ...
4. Align labels less aggressively, especially if it doesn't save fetch
blocks / causes the basic-block to span extra cache-lines.
The optimizations (especially for point 2) make the memchr and
rawmemchr code essentially incompatible so split rawmemchr-evex
to a new file.
Code Size Changes:
memchr-evex.S : -107 bytes
rawmemchr-evex.S : -53 bytes
Net perf changes:
Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.
memchr-evex.S : 0.928
rawmemchr-evex.S : 0.986 (Less targets cross cache lines)
Full results attached in email.
Full check passes on x86-64.
This patch implements following evex512 version of string functions.
evex512 version takes up to 30% less cycle as compared to evex,
depending on length and alignment.
- memchr function using 512 bit vectors.
- rawmemchr function using 512 bit vectors.
- wmemchr function using 512 bit vectors.
Code size data:
memchr-evex.o 762 byte
memchr-evex512.o 576 byte (-24%)
rawmemchr-evex.o 461 byte
rawmemchr-evex512.o 412 byte (-11%)
wmemchr-evex.o 794 byte
wmemchr-evex512.o 552 byte (-30%)
Placeholder function, not used by any processor at the moment.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
In the future, this will result in a compilation failure if the
macros are unexpectedly undefined (due to header inclusion ordering
or header inclusion missing altogether).
Assembler sources are more difficult to convert. In many cases,
they are hand-optimized for the mangling and no-mangling variants,
which is why they are not converted.
sysdeps/s390/s390-32/__longjmp.c and sysdeps/s390/s390-64/__longjmp.c
are special: These are C sources, but most of the implementation is
in assembler, so the PTR_DEMANGLE macro has to be undefined in some
cases, to match the assembler style.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This allows us to define a generic no-op version of PTR_MANGLE and
PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE
unconditionally in C sources, avoiding an unintended loss of hardening
due to missing include files or unlucky header inclusion ordering.
In i386 and x86_64, we can avoid a <tls.h> dependency in the C
code by using the computed constant from <tcb-offsets.h>. <sysdep.h>
no longer includes these definitions, so there is no cyclic dependency
anymore when computing the <tcb-offsets.h> constants.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This way, we can define the pointer guard macros without including
<sysdep.h> on x86-64. Other architectures will not have such an
inclusion dependency, and the implied header file inclusion would
create a porting hazard.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This works around a gcc issue where it const folded inf/inf into nan,
preventing the invalid exception to be signalled.
(x-x)/(x-x) is more robust against optimizations and works for all
out of bounds values including x==nan.
The gcc issue https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95115
should be fixed on release branches starting from gcc-10, but it is
better to change the code in case glibc is built with older gcc.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To avoid duplicate the VMM / GPR / mask insn macros in all incoming
evex512 files use the macros defined in 'reg-macros.h' and
'{vec}-macros.h'
This commit does not change libc.so
Tested build on x86-64
