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https://sourceware.org/git/glibc.git
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645a158978
This commit fixes the bug mentioned in the previous commit. The previous implementations of wmemchr in these files relied on n * sizeof(wchar_t) which was not guranteed by the standard. The new overflow tests added in the previous commit now pass (As well as all the other tests). Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
433 lines
9.7 KiB
ArmAsm
433 lines
9.7 KiB
ArmAsm
/* memchr/wmemchr optimized with AVX2.
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Copyright (C) 2017-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#if IS_IN (libc)
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# include <sysdep.h>
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# ifndef MEMCHR
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# define MEMCHR __memchr_avx2
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# endif
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# ifdef USE_AS_WMEMCHR
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# define VPCMPEQ vpcmpeqd
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# define VPBROADCAST vpbroadcastd
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# define CHAR_SIZE 4
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# else
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# define VPCMPEQ vpcmpeqb
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# define VPBROADCAST vpbroadcastb
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# define CHAR_SIZE 1
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# endif
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# ifdef USE_AS_RAWMEMCHR
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# define ERAW_PTR_REG ecx
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# define RRAW_PTR_REG rcx
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# define ALGN_PTR_REG rdi
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# else
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# define ERAW_PTR_REG edi
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# define RRAW_PTR_REG rdi
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# define ALGN_PTR_REG rcx
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# endif
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# ifndef VZEROUPPER
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# define VZEROUPPER vzeroupper
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# endif
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# ifndef SECTION
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# define SECTION(p) p##.avx
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# endif
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# define VEC_SIZE 32
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# define PAGE_SIZE 4096
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# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
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.section SECTION(.text),"ax",@progbits
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ENTRY (MEMCHR)
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# ifndef USE_AS_RAWMEMCHR
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/* Check for zero length. */
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# ifdef __ILP32__
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/* Clear upper bits. */
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and %RDX_LP, %RDX_LP
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# else
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test %RDX_LP, %RDX_LP
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# endif
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jz L(null)
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# endif
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/* Broadcast CHAR to YMMMATCH. */
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vmovd %esi, %xmm0
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VPBROADCAST %xmm0, %ymm0
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/* Check if we may cross page boundary with one vector load. */
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movl %edi, %eax
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andl $(PAGE_SIZE - 1), %eax
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cmpl $(PAGE_SIZE - VEC_SIZE), %eax
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ja L(cross_page_boundary)
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/* Check the first VEC_SIZE bytes. */
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VPCMPEQ (%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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# ifndef USE_AS_RAWMEMCHR
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/* If length < CHAR_PER_VEC handle special. */
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cmpq $CHAR_PER_VEC, %rdx
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jbe L(first_vec_x0)
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# endif
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testl %eax, %eax
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jz L(aligned_more)
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tzcntl %eax, %eax
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addq %rdi, %rax
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VZEROUPPER_RETURN
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# ifndef USE_AS_RAWMEMCHR
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.p2align 5
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L(first_vec_x0):
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/* Check if first match was before length. */
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tzcntl %eax, %eax
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# ifdef USE_AS_WMEMCHR
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/* NB: Multiply length by 4 to get byte count. */
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sall $2, %edx
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# endif
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xorl %ecx, %ecx
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cmpl %eax, %edx
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leaq (%rdi, %rax), %rax
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cmovle %rcx, %rax
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VZEROUPPER_RETURN
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L(null):
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xorl %eax, %eax
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ret
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# endif
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.p2align 4
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L(cross_page_boundary):
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/* Save pointer before aligning as its original value is
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necessary for computer return address if byte is found or
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adjusting length if it is not and this is memchr. */
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movq %rdi, %rcx
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/* Align data to VEC_SIZE - 1. ALGN_PTR_REG is rcx for memchr
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and rdi for rawmemchr. */
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orq $(VEC_SIZE - 1), %ALGN_PTR_REG
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VPCMPEQ -(VEC_SIZE - 1)(%ALGN_PTR_REG), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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# ifndef USE_AS_RAWMEMCHR
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/* Calculate length until end of page (length checked for a
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match). */
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leaq 1(%ALGN_PTR_REG), %rsi
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subq %RRAW_PTR_REG, %rsi
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# ifdef USE_AS_WMEMCHR
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/* NB: Divide bytes by 4 to get wchar_t count. */
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shrl $2, %esi
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# endif
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# endif
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/* Remove the leading bytes. */
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sarxl %ERAW_PTR_REG, %eax, %eax
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# ifndef USE_AS_RAWMEMCHR
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/* Check the end of data. */
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cmpq %rsi, %rdx
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jbe L(first_vec_x0)
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# endif
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testl %eax, %eax
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jz L(cross_page_continue)
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tzcntl %eax, %eax
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addq %RRAW_PTR_REG, %rax
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L(return_vzeroupper):
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ZERO_UPPER_VEC_REGISTERS_RETURN
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.p2align 4
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L(first_vec_x1):
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tzcntl %eax, %eax
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incq %rdi
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addq %rdi, %rax
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VZEROUPPER_RETURN
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.p2align 4
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L(first_vec_x2):
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tzcntl %eax, %eax
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addq $(VEC_SIZE + 1), %rdi
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addq %rdi, %rax
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VZEROUPPER_RETURN
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.p2align 4
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L(first_vec_x3):
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tzcntl %eax, %eax
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addq $(VEC_SIZE * 2 + 1), %rdi
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addq %rdi, %rax
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VZEROUPPER_RETURN
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.p2align 4
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L(first_vec_x4):
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tzcntl %eax, %eax
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addq $(VEC_SIZE * 3 + 1), %rdi
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addq %rdi, %rax
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VZEROUPPER_RETURN
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.p2align 4
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L(aligned_more):
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/* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time
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since data is only aligned to VEC_SIZE. */
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# ifndef USE_AS_RAWMEMCHR
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L(cross_page_continue):
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/* Align data to VEC_SIZE - 1. */
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xorl %ecx, %ecx
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subl %edi, %ecx
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orq $(VEC_SIZE - 1), %rdi
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/* esi is for adjusting length to see if near the end. */
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leal (VEC_SIZE * 4 + 1)(%rdi, %rcx), %esi
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# ifdef USE_AS_WMEMCHR
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/* NB: Divide bytes by 4 to get the wchar_t count. */
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sarl $2, %esi
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# endif
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# else
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orq $(VEC_SIZE - 1), %rdi
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L(cross_page_continue):
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# endif
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/* Load first VEC regardless. */
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VPCMPEQ 1(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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# ifndef USE_AS_RAWMEMCHR
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/* Adjust length. If near end handle specially. */
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subq %rsi, %rdx
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jbe L(last_4x_vec_or_less)
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# endif
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testl %eax, %eax
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jnz L(first_vec_x1)
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VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x2)
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VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x3)
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VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x4)
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# ifndef USE_AS_RAWMEMCHR
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/* Check if at last VEC_SIZE * 4 length. */
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subq $(CHAR_PER_VEC * 4), %rdx
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jbe L(last_4x_vec_or_less_cmpeq)
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/* Align data to VEC_SIZE * 4 - 1 for the loop and readjust
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length. */
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incq %rdi
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movl %edi, %ecx
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orq $(VEC_SIZE * 4 - 1), %rdi
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andl $(VEC_SIZE * 4 - 1), %ecx
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# ifdef USE_AS_WMEMCHR
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/* NB: Divide bytes by 4 to get the wchar_t count. */
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sarl $2, %ecx
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# endif
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addq %rcx, %rdx
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# else
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/* Align data to VEC_SIZE * 4 - 1 for loop. */
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incq %rdi
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orq $(VEC_SIZE * 4 - 1), %rdi
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# endif
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/* Compare 4 * VEC at a time forward. */
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.p2align 4
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L(loop_4x_vec):
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VPCMPEQ 1(%rdi), %ymm0, %ymm1
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VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm2
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VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm3
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VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm4
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vpor %ymm1, %ymm2, %ymm5
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vpor %ymm3, %ymm4, %ymm6
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vpor %ymm5, %ymm6, %ymm5
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vpmovmskb %ymm5, %ecx
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# ifdef USE_AS_RAWMEMCHR
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subq $-(VEC_SIZE * 4), %rdi
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testl %ecx, %ecx
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jz L(loop_4x_vec)
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# else
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testl %ecx, %ecx
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jnz L(loop_4x_vec_end)
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subq $-(VEC_SIZE * 4), %rdi
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subq $(CHAR_PER_VEC * 4), %rdx
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ja L(loop_4x_vec)
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/* Fall through into less than 4 remaining vectors of length
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case. */
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VPCMPEQ (VEC_SIZE * 0 + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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.p2align 4
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L(last_4x_vec_or_less):
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# ifdef USE_AS_WMEMCHR
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/* NB: Multiply length by 4 to get byte count. */
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sall $2, %edx
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# endif
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/* Check if first VEC contained match. */
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testl %eax, %eax
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jnz L(first_vec_x1_check)
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/* If remaining length > VEC_SIZE * 2. */
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addl $(VEC_SIZE * 2), %edx
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jg L(last_4x_vec)
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L(last_2x_vec):
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/* If remaining length < VEC_SIZE. */
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addl $VEC_SIZE, %edx
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jle L(zero_end)
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/* Check VEC2 and compare any match with remaining length. */
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VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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tzcntl %eax, %eax
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cmpl %eax, %edx
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jbe L(set_zero_end)
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addq $(VEC_SIZE + 1), %rdi
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addq %rdi, %rax
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L(zero_end):
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VZEROUPPER_RETURN
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.p2align 4
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L(loop_4x_vec_end):
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# endif
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/* rawmemchr will fall through into this if match was found in
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loop. */
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(last_vec_x1_return)
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vpmovmskb %ymm2, %eax
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testl %eax, %eax
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jnz L(last_vec_x2_return)
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vpmovmskb %ymm3, %eax
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/* Combine VEC3 matches (eax) with VEC4 matches (ecx). */
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salq $32, %rcx
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orq %rcx, %rax
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tzcntq %rax, %rax
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# ifdef USE_AS_RAWMEMCHR
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subq $(VEC_SIZE * 2 - 1), %rdi
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# else
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subq $-(VEC_SIZE * 2 + 1), %rdi
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# endif
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addq %rdi, %rax
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VZEROUPPER_RETURN
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# ifndef USE_AS_RAWMEMCHR
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.p2align 4
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L(first_vec_x1_check):
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tzcntl %eax, %eax
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/* Adjust length. */
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subl $-(VEC_SIZE * 4), %edx
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/* Check if match within remaining length. */
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cmpl %eax, %edx
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jbe L(set_zero_end)
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incq %rdi
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addq %rdi, %rax
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VZEROUPPER_RETURN
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.p2align 4
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L(set_zero_end):
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xorl %eax, %eax
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VZEROUPPER_RETURN
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# endif
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.p2align 4
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L(last_vec_x1_return):
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tzcntl %eax, %eax
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# ifdef USE_AS_RAWMEMCHR
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subq $(VEC_SIZE * 4 - 1), %rdi
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# else
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incq %rdi
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# endif
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addq %rdi, %rax
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VZEROUPPER_RETURN
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.p2align 4
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L(last_vec_x2_return):
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tzcntl %eax, %eax
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# ifdef USE_AS_RAWMEMCHR
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subq $(VEC_SIZE * 3 - 1), %rdi
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# else
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subq $-(VEC_SIZE + 1), %rdi
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# endif
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addq %rdi, %rax
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VZEROUPPER_RETURN
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# ifndef USE_AS_RAWMEMCHR
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.p2align 4
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L(last_4x_vec_or_less_cmpeq):
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VPCMPEQ (VEC_SIZE * 4 + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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# ifdef USE_AS_WMEMCHR
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/* NB: Multiply length by 4 to get byte count. */
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sall $2, %edx
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# endif
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subq $-(VEC_SIZE * 4), %rdi
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/* Check first VEC regardless. */
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testl %eax, %eax
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jnz L(first_vec_x1_check)
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/* If remaining length <= CHAR_PER_VEC * 2. */
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addl $(VEC_SIZE * 2), %edx
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jle L(last_2x_vec)
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.p2align 4
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L(last_4x_vec):
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VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(last_vec_x2_return)
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VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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/* Create mask for possible matches within remaining length. */
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movq $-1, %rcx
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bzhiq %rdx, %rcx, %rcx
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/* Test matches in data against length match. */
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andl %ecx, %eax
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jnz L(last_vec_x3)
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/* if remaining length <= VEC_SIZE * 3 (Note this is after
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remaining length was found to be > VEC_SIZE * 2. */
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subl $VEC_SIZE, %edx
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jbe L(zero_end2)
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VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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/* Shift remaining length mask for last VEC. */
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shrq $32, %rcx
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andl %ecx, %eax
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jz L(zero_end2)
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tzcntl %eax, %eax
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addq $(VEC_SIZE * 3 + 1), %rdi
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addq %rdi, %rax
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L(zero_end2):
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VZEROUPPER_RETURN
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.p2align 4
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L(last_vec_x3):
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tzcntl %eax, %eax
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subq $-(VEC_SIZE * 2 + 1), %rdi
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addq %rdi, %rax
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VZEROUPPER_RETURN
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# endif
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END (MEMCHR)
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#endif
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