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* Update copyright dates with scripts/update-copyrightsJoseph Myers2023-01-061168-1168/+1168
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* stdio-common: Convert vfprintf and related functions to buffersFlorian Weimer2022-12-191-18/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vfprintf is entangled with vfwprintf (of course), __printf_fp, __printf_fphex, __vstrfmon_l_internal, and the strfrom family of functions. The latter use the internal snprintf functionality, so vsnprintf is converted as well. The simples conversion is __printf_fphex, followed by __vstrfmon_l_internal and __printf_fp, and finally __vfprintf_internal and __vfwprintf_internal. __vsnprintf_internal and strfrom* are mostly consuming the new interfaces, so they are comparatively simple. __printf_fp is a public symbol, so the FILE *-based interface had to preserved. The __printf_fp rewrite does not change the actual binary-to-decimal conversion algorithm, and digits are still not emitted directly to the target buffer. However, the staging buffer now uses bytes instead of wide characters, and one buffer copy is eliminated. The changes are at least performance-neutral in my testing. Floating point printing and snprintf improved measurably, so that this Lua script for i=1,5000000 do print(i, i * math.pi) end runs about 5% faster for me. To preserve fprintf performance for a simple "%d" format, this commit has some logic changes under LABEL (unsigned_number) to avoid additional function calls. There are certainly some very easy performance improvements here: binary, octal and hexadecimal formatting can easily avoid the temporary work buffer (the number of digits can be computed ahead-of-time using one of the __builtin_clz* built-ins). Decimal formatting can use a specialized version of _itoa_word for base 10. The existing (inconsistent) width handling between strfmon and printf is preserved here. __print_fp_buffer_1 would have to use __translated_number_width to achieve ISO conformance for printf. Test expectations in libio/tst-vtables-common.c are adjusted because the internal staging buffer merges all virtual function calls into one. In general, stack buffer usage is greatly reduced, particularly for unbuffered input streams. __printf_fp can still use a large buffer in binary128 mode for %g, though. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* x86: Prevent SIGSEGV in memcmp-sse2 when data is concurrently modified [BZ ↵Noah Goldstein2022-12-151-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | #29863] In the case of INCORRECT usage of `memcmp(a, b, N)` where `a` and `b` are concurrently modified as `memcmp` runs, there can be a SIGSEGV in `L(ret_nonzero_vec_end_0)` because the sequential logic assumes that `(rdx - 32 + rax)` is a positive 32-bit integer. To be clear, this change does not mean the usage of `memcmp` is supported. The program behaviour is undefined (UB) in the presence of data races, and `memcmp` is incorrect when the values of `a` and/or `b` are modified concurrently (data race). This UB may manifest itself as a SIGSEGV. That being said, if we can allow the idiomatic use cases, like those in yottadb with opportunistic concurrency control (OCC), to execute without a SIGSEGV, at no cost to regular use cases, then we can aim to minimize harm to those existing users. The fix replaces a 32-bit `addl %edx, %eax` with the 64-bit variant `addq %rdx, %rax`. The 1-extra byte of code size from using the 64-bit instruction doesn't contribute to overall code size as the next target is aligned and has multiple bytes of `nop` padding before it. As well all the logic between the add and `ret` still fits in the same fetch block, so the cost of this change is basically zero. The relevant sequential logic can be seen in the following pseudo-code: ``` /* * rsi = a * rdi = b * rdx = len - 32 */ /* cmp a[0:15] and b[0:15]. Since length is known to be [17, 32] in this case, this check is also assumed to cover a[0:(31 - len)] and b[0:(31 - len)]. */ movups (%rsi), %xmm0 movups (%rdi), %xmm1 PCMPEQ %xmm0, %xmm1 pmovmskb %xmm1, %eax subl %ecx, %eax jnz L(END_NEQ) /* cmp a[len-16:len-1] and b[len-16:len-1]. */ movups 16(%rsi, %rdx), %xmm0 movups 16(%rdi, %rdx), %xmm1 PCMPEQ %xmm0, %xmm1 pmovmskb %xmm1, %eax subl %ecx, %eax jnz L(END_NEQ2) ret L(END2): /* Position first mismatch. */ bsfl %eax, %eax /* The sequential version is able to assume this value is a positive 32-bit value because the first check included bytes in range a[0:(31 - len)] and b[0:(31 - len)] so `eax` must be greater than `31 - len` so the minimum value of `edx` + `eax` is `(len - 32) + (32 - len) >= 0`. In the concurrent case, however, `a` or `b` could have been changed so a mismatch in `eax` less or equal than `(31 - len)` is possible (the new low bound is `(16 - len)`. This can result in a negative 32-bit signed integer, which when zero extended to 64-bits is a random large value this out out of bounds. */ addl %edx, %eax /* Crash here because 32-bit negative number in `eax` zero extends to out of bounds 64-bit offset. */ movzbl 16(%rdi, %rax), %ecx movzbl 16(%rsi, %rax), %eax ``` This fix is quite simple, just make the `addl %edx, %eax` 64 bit (i.e `addq %rdx, %rax`). This prevents the 32-bit zero extension and since `eax` is still a low bound of `16 - len` the `rdx + rax` is bound by `(len - 32) - (16 - len) >= -16`. Since we have a fixed offset of `16` in the memory access this must be in bounds.
* x86-64 strncpy: Properly handle the length parameter [BZ# 29839]H.J. Lu2022-12-022-0/+8
| | | | | | | | | | | | On x32, the size_t parameter may be passed in the lower 32 bits of a 64-bit register with the non-zero upper 32 bits. The string/memory functions written in assembly can only use the lower 32 bits of a 64-bit register as length or must clear the upper 32 bits before using the full 64-bit register for length. This pach fixes strncpy for x32. Tested on x86-64 and x32. On x86-64, libc.so is the same with and without the fix. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* x86-64 strncat: Properly handle the length parameter [BZ# 24097]H.J. Lu2022-12-025-1/+73
| | | | | | | | | | | | On x32, the size_t parameter may be passed in the lower 32 bits of a 64-bit register with the non-zero upper 32 bits. The string/memory functions written in assembly can only use the lower 32 bits of a 64-bit register as length or must clear the upper 32 bits before using the full 64-bit register for length. This pach fixes strncat for x32. Tested on x86-64 and x32. On x86-64, libc.so is the same with and without the fix. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* x86/fpu: Factor out shared avx2/avx512 code in svml_{s|d}_wrapper_impl.hNoah Goldstein2022-11-273-342/+192
| | | | | | | Code is exactly the same for the two so better to only maintain one version. All math and mathvec tests pass on x86.
* x86/fpu: Cleanup code in svml_{s|d}_wrapper_impl.hNoah Goldstein2022-11-272-242/+172
| | | | | | | 1. Remove unnecessary spills. 2. Fix some small nit missed optimizations. All math and mathvec tests pass on x86.
* x86/fpu: Reformat svml_{s|d}_wrapper_impl.hNoah Goldstein2022-11-272-510/+510
| | | | | Just reformat with the style convention used in other x86 assembler files. This doesn't change libm.so or libmvec.so.
* x86/fpu: Fix misspelled evex512 section in variety of svml filesNoah Goldstein2022-11-2721-21/+21
| | | | | | | | | | | | ``` .section .text.evex512, "ax", @progbits ``` With misspelled as: ``` .section .text.exex512, "ax", @progbits ```
* x86/fpu: Add missing ISA sections to variety of svml filesNoah Goldstein2022-11-27198-198/+198
| | | | Many sse4/avx2/avx512 files where just in .text.
* x86: Add avx2 optimized functions for the wchar_t strcpy familyNoah Goldstein2022-11-0827-18/+115
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implemented: wcscat-avx2 (+ 744 bytes wcscpy-avx2 (+ 539 bytes) wcpcpy-avx2 (+ 577 bytes) wcsncpy-avx2 (+1108 bytes) wcpncpy-avx2 (+1214 bytes) wcsncat-avx2 (+1085 bytes) Performance Changes: Times are from N = 10 runs of the benchmark suite and are reported as geometric mean of all ratios of New Implementation / Best Old Implementation. Best Old Implementation was determined with the highest ISA implementation. wcscat-avx2 -> 0.975 wcscpy-avx2 -> 0.591 wcpcpy-avx2 -> 0.698 wcsncpy-avx2 -> 0.730 wcpncpy-avx2 -> 0.711 wcsncat-avx2 -> 0.954 Code Size Changes: This change increase the size of libc.so by ~5.5kb bytes. For reference the patch optimizing the normal strcpy family functions decreases libc.so by ~5.2kb. Full check passes on x86-64 and build succeeds for all ISA levels w/ and w/o multiarch.
* x86: Add evex optimized functions for the wchar_t strcpy familyNoah Goldstein2022-11-0833-7/+858
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implemented: wcscat-evex (+ 905 bytes) wcscpy-evex (+ 674 bytes) wcpcpy-evex (+ 709 bytes) wcsncpy-evex (+1358 bytes) wcpncpy-evex (+1467 bytes) wcsncat-evex (+1213 bytes) Performance Changes: Times are from N = 10 runs of the benchmark suite and are reported as geometric mean of all ratios of New Implementation / Best Old Implementation. Best Old Implementation was determined with the highest ISA implementation. wcscat-evex -> 0.991 wcscpy-evex -> 0.587 wcpcpy-evex -> 0.695 wcsncpy-evex -> 0.719 wcpncpy-evex -> 0.694 wcsncat-evex -> 0.979 Code Size Changes: This change increase the size of libc.so by ~6.3kb bytes. For reference the patch optimizing the normal strcpy family functions decreases libc.so by ~5.7kb. Full check passes on x86-64 and build succeeds for all ISA levels w/ and w/o multiarch.
* x86: Optimize and shrink st{r|p}{n}{cat|cpy}-avx2 functionsNoah Goldstein2022-11-0813-1234/+1594
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Optimizations are: 1. Use more overlapping stores to avoid branches. 2. Reduce how unrolled the aligning copies are (this is more of a code-size save, its a negative for some sizes in terms of perf). 3. For st{r|p}n{cat|cpy} re-order the branches to minimize the number that are taken. Performance Changes: Times are from N = 10 runs of the benchmark suite and are reported as geometric mean of all ratios of New Implementation / Old Implementation. strcat-avx2 -> 0.998 strcpy-avx2 -> 0.937 stpcpy-avx2 -> 0.971 strncpy-avx2 -> 0.793 stpncpy-avx2 -> 0.775 strncat-avx2 -> 0.962 Code Size Changes: function -> Bytes New / Bytes Old -> Ratio strcat-avx2 -> 685 / 1639 -> 0.418 strcpy-avx2 -> 560 / 903 -> 0.620 stpcpy-avx2 -> 592 / 939 -> 0.630 strncpy-avx2 -> 1176 / 2390 -> 0.492 stpncpy-avx2 -> 1268 / 2438 -> 0.520 strncat-avx2 -> 1042 / 2563 -> 0.407 Notes: 1. Because of the significant difference between the implementations they are split into three files. strcpy-avx2.S -> strcpy, stpcpy, strcat strncpy-avx2.S -> strncpy strncat-avx2.S > strncat I couldn't find a way to merge them without making the ifdefs incredibly difficult to follow. Full check passes on x86-64 and build succeeds for all ISA levels w/ and w/o multiarch.
* x86: Optimize and shrink st{r|p}{n}{cat|cpy}-evex functionsNoah Goldstein2022-11-087-1173/+2115
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Optimizations are: 1. Use more overlapping stores to avoid branches. 2. Reduce how unrolled the aligning copies are (this is more of a code-size save, its a negative for some sizes in terms of perf). 3. Improve the loop a bit (similiar to what we do in strlen with 2x vpminu + kortest instead of 3x vpminu + kmov + test). 4. For st{r|p}n{cat|cpy} re-order the branches to minimize the number that are taken. Performance Changes: Times are from N = 10 runs of the benchmark suite and are reported as geometric mean of all ratios of New Implementation / Old Implementation. stpcpy-evex -> 0.922 strcat-evex -> 0.985 strcpy-evex -> 0.880 strncpy-evex -> 0.831 stpncpy-evex -> 0.780 strncat-evex -> 0.958 Code Size Changes: function -> Bytes New / Bytes Old -> Ratio strcat-evex -> 819 / 1874 -> 0.437 strcpy-evex -> 700 / 1074 -> 0.652 stpcpy-evex -> 735 / 1094 -> 0.672 strncpy-evex -> 1397 / 2611 -> 0.535 stpncpy-evex -> 1489 / 2691 -> 0.553 strncat-evex -> 1184 / 2832 -> 0.418 Notes: 1. Because of the significant difference between the implementations they are split into three files. strcpy-evex.S -> strcpy, stpcpy, strcat strncpy-evex.S -> strncpy strncat-evex.S > strncat I couldn't find a way to merge them without making the ifdefs incredibly difficult to follow. 2. All implementations can be made evex512 by including "x86-evex512-vecs.h" at the top. 3. All implementations have an optional define: `USE_EVEX_MASKED_STORE` Setting to one uses evex-masked stores for handling short strings. This saves code size and branches. It's disabled for all implementations are the moment as there are some serious drawbacks to masked stores in certain cases, but that may be fixed on future architectures. Full check passes on x86-64 and build succeeds for all ISA levels w/ and w/o multiarch.
* x86: Use VMM API in memcmpeq-evex.S and minor changesNoah Goldstein2022-11-081-100/+155
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Changes to generated code are: 1. In a few places use `vpcmpeqb` instead of `vpcmpneq` to save a byte of code size. 2. Add a branch for length <= (VEC_SIZE * 6) as opposed to doing the entire block of [VEC_SIZE * 4 + 1, VEC_SIZE * 8] in a single basic-block (the space to add the extra branch without changing code size is bought with the above change). Change (2) has roughly a 20-25% speedup for sizes in [VEC_SIZE * 4 + 1, VEC_SIZE * 6] and negligible to no-cost for [VEC_SIZE * 6 + 1, VEC_SIZE * 8] From N=10 runs on Tigerlake: align1,align2 ,length ,result ,New Time ,Cur Time ,New Time / Old Time 0 ,0 ,129 ,0 ,5.404 ,6.887 ,0.785 0 ,0 ,129 ,1 ,5.308 ,6.826 ,0.778 0 ,0 ,129 ,18446744073709551615 ,5.359 ,6.823 ,0.785 0 ,0 ,161 ,0 ,5.284 ,6.827 ,0.774 0 ,0 ,161 ,1 ,5.317 ,6.745 ,0.788 0 ,0 ,161 ,18446744073709551615 ,5.406 ,6.778 ,0.798 0 ,0 ,193 ,0 ,6.804 ,6.802 ,1.000 0 ,0 ,193 ,1 ,6.950 ,6.754 ,1.029 0 ,0 ,193 ,18446744073709551615 ,6.792 ,6.719 ,1.011 0 ,0 ,225 ,0 ,6.625 ,6.699 ,0.989 0 ,0 ,225 ,1 ,6.776 ,6.735 ,1.003 0 ,0 ,225 ,18446744073709551615 ,6.758 ,6.738 ,0.992 0 ,0 ,256 ,0 ,5.402 ,5.462 ,0.989 0 ,0 ,256 ,1 ,5.364 ,5.483 ,0.978 0 ,0 ,256 ,18446744073709551615 ,5.341 ,5.539 ,0.964 Rewriting with VMM API allows for memcmpeq-evex to be used with evex512 by including "x86-evex512-vecs.h" at the top. Complete check passes on x86-64.
* x86: Use VMM API in memcmp-evex-movbe.S and minor changesNoah Goldstein2022-11-081-133/+175
| | | | | | | | | | The only change to the existing generated code is `tzcnt` -> `bsf` to save a byte of code size here and there. Rewriting with VMM API allows for memcmp-evex-movbe to be used with evex512 by including "x86-evex512-vecs.h" at the top. Complete check passes on x86-64.
* x86_64: Implement evex512 version of strrchr and wcsrchrSunil K Pandey2022-11-035-0/+297
| | | | | | | | | | | | | | | | | | | | | | | | | | | Changes from v1: Use vec api for register. Replace VPCMP with VPCMPEQ Restructure and remove 1 unconditional jump. Change page cross logic to use sall. 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. - strrchr function using 512 bit vectors. - wcsrchr function using 512 bit vectors. Code size data: strrchr-evex.o 879 byte strrchr-evex512.o 601 byte (-32%) wcsrchr-evex.o 882 byte wcsrchr-evex512.o 572 byte (-35%) Placeholder function, not used by any processor at the moment. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* elf: Introduce <dl-call_tls_init_tp.h> and call_tls_init_tp (bug 29249)Florian Weimer2022-11-031-1/+1
| | | | | | | | This makes it more likely that the compiler can compute the strlen argument in _startup_fatal at compile time, which is required to avoid a dependency on strlen this early during process startup. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* elf: Rework exception handling in the dynamic loader [BZ #25486]Florian Weimer2022-11-031-5/+0
| | | | | | | | | | | | | | | | | | | | | | | The old exception handling implementation used function interposition to replace the dynamic loader implementation (no TLS support) with the libc implementation (TLS support). This results in problems if the link order between the dynamic loader and libc is reversed (bug 25486). The new implementation moves the entire implementation of the exception handling functions back into the dynamic loader, using THREAD_GETMEM and THREAD_SETMEM for thread-local data support. These depends on Hurd support for these macros, added in commit b65a82e4e757c1e6cb7073916 ("hurd: Add THREAD_GET/SETMEM/_NC"). One small obstacle is that the exception handling facilities are used before the TCB has been set up, so a check is needed if the TCB is available. If not, a regular global variable is used to store the exception handling information. Also rename dl-error.c to dl-catch.c, to avoid confusion with the dlerror function. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* Fix build with GCC 13 _FloatN, _FloatNx built-in functionsJoseph Myers2022-10-311-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | GCC 13 has added more _FloatN and _FloatNx versions of existing <math.h> and <complex.h> built-in functions, for use in libstdc++-v3. This breaks the glibc build because of how those functions are defined as aliases to functions with the same ABI but different types. Add appropriate -fno-builtin-* options for compiling relevant files, as already done for the case of long double functions aliasing double ones and based on the list of files used there. I fixed some mistakes in that list of double files that I noticed while implementing this fix, but there may well be more such (harmless) cases, in this list or the new one (files that don't actually exist or don't define the named functions as aliases so don't need the options). I did try to exclude cases where glibc doesn't define certain functions for _FloatN or _FloatNx types at all from the new uses of -fno-builtin-* options. As with the options for double files (see the commit message for commit 49348beafe9ba150c9bd48595b3f372299bddbb0, "Fix build with GCC 10 when long double = double."), it's deliberate that the options are used even if GCC currently doesn't have a built-in version of a given functions, so providing some level of future-proofing against more such built-in functions being added in future. Tested with build-many-glibcs.py for aarch64-linux-gnu powerpc-linux-gnu powerpc64le-linux-gnu x86_64-linux-gnu (compilers and glibcs builds) with GCC mainline.
* x86-64: Improve evex512 version of strlen functionsSunil K Pandey2022-10-301-34/+57
| | | | | | | | | | | This patch improves following functionality - Replace VPCMP with VPCMPEQ. - Replace page cross check logic with sall. - Remove extra lea from align_more. - Remove uncondition loop jump. - Use bsf to check max length in first vector. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* x86_64: Implement evex512 version of strchrnul, strchr and wcschrSunil K Pandey2022-10-256-0/+322
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Remove htonl.S for i386/x86_64Cristian Rodríguez2022-10-241-34/+0
| | | | | | | 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>
* x86: Use `testb` for FSRM check in memmove-vec-unaligned-ermsNoah Goldstein2022-10-201-0/+4
| | | | | | | `testb` saves a bit of code size is the imm-operand can be encoded 1-bytes. Tested on x86-64.
* x86: Use `testb` for case-locale check in str{n}casecmp-sse42Noah Goldstein2022-10-201-2/+2
| | | | | | | `testb` saves a bit of code size is the imm-operand can be encoded 1-bytes. Tested on x86-64.
* x86: Use `testb` for case-locale check in str{n}casecmp-sse2Noah Goldstein2022-10-201-2/+2
| | | | | | | `testb` saves a bit of code size is the imm-operand can be encoded 1-bytes. Tested on x86-64.
* x86: Use `testb` for case-locale check in str{n}casecmp-avx2Noah Goldstein2022-10-201-1/+1
| | | | | | | `testb` saves a bit of code size is the imm-operand can be encoded 1-bytes. Tested on x86-64.
* x86: Add support for VEC_SIZE == 64 in strcmp-evex.S implNoah Goldstein2022-10-201-246/+438
| | | | | | | | | | | | | | | 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.
* x86: Remove AVX512-BVMI2 instruction from strrchr-evex.SNoah Goldstein2022-10-201-40/+29
| | | | | | | | | | | | | | | | commit b412213eee0afa3b51dfe92b736dfc7c981309f5 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.
* x86: Optimize strrchr-evex.S and implement with VMM headersNoah Goldstein2022-10-191-171/+200
| | | | | | | | | | | | | | | | | | | | | 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.
* x86: Optimize memrchr-evex.SNoah Goldstein2022-10-191-214/+324
| | | | | | | | | | | | | | | | | | | | | | | | | 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.
* x86: Optimize strnlen-evex.S and implement with VMM headersNoah Goldstein2022-10-193-404/+572
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* x86: Shrink / minorly optimize strchr-evex and implement with VMM headersNoah Goldstein2022-10-191-218/+340
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* x86: Optimize memchr-evex.S and implement with VMM headersNoah Goldstein2022-10-193-410/+851
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* x86_64: Implement evex512 version of memchr, rawmemchr and wmemchrSunil K Pandey2022-10-186-0/+346
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sourcesFlorian Weimer2022-10-181-2/+0
| | | | | | | | | | | | | | | | | 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>
* Introduce <pointer_guard.h>, extracted from <sysdep.h>Florian Weimer2022-10-183-0/+3
| | | | | | | | | | | | | | 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>
* x86-64: Move LP_SIZE definition to its own headerFlorian Weimer2022-10-184-11/+48
| | | | | | | | | 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>
* x86: Update strlen-evex-base to use new reg/vec macros.Noah Goldstein2022-10-142-76/+44
| | | | | | | | | | 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
* x86: Remove now unused vec header macros.Noah Goldstein2022-10-147-328/+0
| | | | | | This commit does not change libc.so Tested build on x86-64
* x86: Update memset to use new VEC macrosNoah Goldstein2022-10-146-99/+43
| | | | | | | | Replace %VEC(n) -> %VMM(n) This commit does not change libc.so Tested build on x86-64
* x86: Update memmove to use new VEC macrosNoah Goldstein2022-10-146-221/+132
| | | | | | | | Replace %VEC(n) -> %VMM(n) This commit does not change libc.so Tested build on x86-64
* x86: Update memrchr to use new VEC macrosNoah Goldstein2022-10-141-21/+21
| | | | | | | | Replace %VEC(n) -> %VMM(n) This commit does not change libc.so Tested build on x86-64
* x86: Update VEC macros to complete API for evex/evex512 implsNoah Goldstein2022-10-149-0/+635
| | | | | | | | | | | | | | | | | | | | | | | 1) Copy so that backport will be easier. 2) Make section only define if there is not a previous definition 3) Add `VEC_lo` definition for proper reg-width but in the ymm/zmm0-15 range. 4) Add macros for accessing GPRs based on VEC_SIZE This is to make it easier to do think like: ``` vpcmpb %VEC(0), %VEC(1), %k0 kmov{d|q} %k0, %{eax|rax} test %{eax|rax} ``` It adds macro s.t any GPR can get the proper width with: `V{upcase_GPR_name}` and any mask insn can get the proper width with: `{upcase_mask_insn_without_postfix}` This commit does not change libc.so Tested build on x86-64
* elf: Remove -fno-tree-loop-distribute-patterns usage on dl-supportAdhemerval Zanella2022-10-101-0/+34
| | | | | | | | | | | | | | Besides the option being gcc specific, this approach is still fragile and not future proof since we do not know if this will be the only optimization option gcc will add that transforms loops to memset (or any libcall). This patch adds a new header, dl-symbol-redir-ifunc.h, that can b used to redirect the compiler generated libcalls to port the generic memset implementation if required. Checked on x86_64-linux-gnu and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* x86_64: Remove platform directory library loading testJavier Pello2022-10-063-64/+0
| | | | | | | | | This was to test loading of shared libraries from platform subdirectories, but this functionality is going away in the following commits. Signed-off-by: Javier Pello <devel@otheo.eu> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* x86: Fix -Os build (BZ #29576)Adhemerval Zanella Netto2022-10-051-0/+18
| | | | | | | | | | | The compiler might transform __stpcpy calls (which are routed to __builtin_stpcpy as an optimization) to strcpy and x86_64 strcpy multiarch implementation does not build any working symbol due ISA_SHOULD_BUILD not being evaluated for IS_IN(rtld). Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* x86-64: Require BMI1/BMI2 for AVX2 strrchr and wcsrchr implementationsAurelien Jarno2022-10-032-3/+15
| | | | | | | | | | | The AVX2 strrchr and wcsrchr implementation uses the 'blsmsk' instruction which belongs to the BMI1 CPU feature and the 'shrx' instruction, which belongs to the BMI2 CPU feature. Fixes: df7e295d18ff ("x86: Optimize {str|wcs}rchr-avx2") Partially resolves: BZ #29611 Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* x86-64: Require BMI2 and LZCNT for AVX2 memrchr implementationAurelien Jarno2022-10-032-2/+9
| | | | | | | | | | | The AVX2 memrchr implementation uses the 'shlxl' instruction, which belongs to the BMI2 CPU feature and uses the 'lzcnt' instruction, which belongs to the LZCNT CPU feature. Fixes: af5306a735eb ("x86: Optimize memrchr-avx2.S") Partially resolves: BZ #29611 Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* x86-64: Require BMI2 for AVX2 (raw|w)memchr implementationsAurelien Jarno2022-10-031-3/+9
| | | | | | | | | | The AVX2 memchr, rawmemchr and wmemchr implementations use the 'bzhi' and 'sarx' instructions, which belongs to the BMI2 CPU feature. Fixes: acfd088a1963 ("x86: Optimize memchr-avx2.S") Partially resolves: BZ #29611 Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-11-07 12:13:39 +0000