From 9cba898481368ce16c6a2d30ef781a82dce27c55 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 13 Jul 2020 10:33:47 -0700 Subject: [PATCH] x86: Pass a copy of the string length to cmpstrnqi cmpstrnsi expander may pass the actual string length directly to cmpstrnqi patterns. For cmpstrnsi, one of the strings must be a constant and expand_builtin_strncmp rewrites the length argument to be the minimum of the const string length and the actual string length. But it is not the case for cmpmemsi. Pass a copy of the string length to cmpstrnqi patterns to avoid changing the actual string length by cmpstrnqi patterns. gcc/ PR target/95443 * config/i386/i386.md (cmpstrnsi): Pass a copy of the string length to cmpstrnqi patterns. gcc/testsuite/ PR target/95443 * gcc.target/i386/pr95443-1.c: New test. * gcc.target/i386/pr95443-2.c: Likewise. --- gcc/config/i386/i386.md | 6 +- gcc/testsuite/gcc.target/i386/pr95443-1.c | 130 ++++++++++++++++++++++++++++++ gcc/testsuite/gcc.target/i386/pr95443-2.c | 79 ++++++++++++++++++ 3 files changed, 214 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr95443-1.c create mode 100644 gcc/testsuite/gcc.target/i386/pr95443-2.c diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md index d0ecd9e..b24a455 100644 --- a/gcc/config/i386/i386.md +++ b/gcc/config/i386/i386.md @@ -18057,7 +18057,11 @@ if (addr2 != XEXP (operands[2], 0)) operands[2] = replace_equiv_address_nv (operands[2], addr2); - countreg = ix86_zero_extend_to_Pmode (operands[3]); + /* NB: Make a copy of the data length to avoid changing the original + data length by cmpstrnqi patterns. */ + rtx count = ix86_zero_extend_to_Pmode (operands[3]); + countreg = gen_reg_rtx (Pmode); + emit_move_insn (countreg, count); /* %%% Iff we are testing strict equality, we can use known alignment to good advantage. This may be possible with combine, particularly diff --git a/gcc/testsuite/gcc.target/i386/pr95443-1.c b/gcc/testsuite/gcc.target/i386/pr95443-1.c new file mode 100644 index 0000000..292ff16 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr95443-1.c @@ -0,0 +1,130 @@ +/* { dg-do run { target mmap } } */ +/* { dg-options "-O2 -minline-all-stringops" } */ + +#include +#include +#include +#include +#include +#ifndef MAP_ANON +#define MAP_ANON 0 +#endif +#ifndef MAP_FAILED +#define MAP_FAILED ((void *)-1) +#endif + +uint8_t shift[256]; + +static size_t +__attribute__ ((noclone, noinline)) +hash2(const unsigned char *p) +{ + return (((size_t)(p)[0] - ((size_t)(p)[-1] << 3)) % sizeof (shift)); +} + +char * +simple_strstr (const char *haystack, const char *needle) +{ + const unsigned char *hs = (const unsigned char *) haystack; + const unsigned char *ne = (const unsigned char *) needle; + size_t ne_len = strlen ((const char*)ne); + size_t hs_len = strnlen ((const char*)hs, ne_len | 512); + + if (hs_len < ne_len) + return NULL; + + if (memcmp (hs, ne, ne_len) == 0) + return (char *) hs; + + const unsigned char *end = hs + hs_len - ne_len; + size_t tmp, shift1; + size_t m1 = ne_len - 1; + size_t offset = 0; + + memset (shift, 0, sizeof (shift)); + for (int i = 1; i < m1; i++) + shift[hash2 (ne + i)] = i; + shift1 = m1 - shift[hash2 (ne + m1)]; + shift[hash2 (ne + m1)] = m1; + + while (1) + { + if (__glibc_unlikely (hs > end)) + { + end += strnlen ((const char*)end + m1 + 1, 2048); + if (hs > end) + return NULL; + } + + do + { + hs += m1; + tmp = shift[hash2 (hs)]; + } + while (tmp == 0 && hs <= end); + + hs -= tmp; + if (tmp < m1) + continue; + + if (m1 < 15 || memcmp (hs + offset, ne + offset, 8) == 0) + { + if (memcmp (hs, ne, m1) == 0) + return (void *) hs; + + offset = (offset >= 8 ? offset : m1) - 8; + } + + hs += shift1; + } +} + +static int +check_result (const char *s1, const char *s2, + char *exp_result) +{ + char *result = simple_strstr (s1, s2); + if (result != exp_result) + return -1; + + return 0; +} + +void +__attribute__ ((noclone, noinline)) +check1 (void) +{ + const char s1[] = + "F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD_C3_A7_20_EF_BF_BD"; + const char s2[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"; + char *exp_result; + + exp_result = simple_strstr (s1, s2); + if (check_result (s1, s2, exp_result) != 0) + abort (); +} + +int +main (void) +{ + unsigned char *buf1, *buf2; + size_t page_size = 2 * sysconf(_SC_PAGESIZE); + buf1 = mmap (0, (1 + 1) * page_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON, -1, 0); + if (buf1 == MAP_FAILED) + return -1; + if (mprotect (buf1 + 1 * page_size, page_size, PROT_NONE)) + return -1; + buf2 = mmap (0, 2 * page_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON, -1, 0); + if (buf2 == MAP_FAILED) + return -1; + if (mprotect (buf2 + page_size, page_size, PROT_NONE)) + return -1; + + memset (buf1, 0xa5, 1 * page_size); + memset (buf2, 0x5a, page_size); + + check1 (); + return 0; +} diff --git a/gcc/testsuite/gcc.target/i386/pr95443-2.c b/gcc/testsuite/gcc.target/i386/pr95443-2.c new file mode 100644 index 0000000..23bb13a --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr95443-2.c @@ -0,0 +1,79 @@ +/* { dg-do run { target mmap } } */ +/* { dg-options "-O2 -minline-all-stringops" } */ + +#include +#include +#include +#include +#include +#ifndef MAP_ANON +#define MAP_ANON 0 +#endif +#ifndef MAP_FAILED +#define MAP_FAILED ((void *)-1) +#endif + +int ret; + +static void +do_one_test (char *dst, char *src, const char *orig_src, unsigned int len) +{ + __builtin_memcpy (src, orig_src, len); + __builtin_memmove (dst, src, len); + + if (__builtin_memcmp (dst, orig_src, len) != 0) + { + ret = 1; + return; + } +} + +void +do_test (char *s1, char *s2, int n, unsigned int len) +{ + int i; + for (i = 0; i < n; i++) + do_one_test (s2, s2, s1, len); +} + +int +main (void) +{ + unsigned char *buf1, *buf2; + size_t page_size = 2 * sysconf(_SC_PAGESIZE); + + buf1 = mmap (0, (1 + 1) * page_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON, -1, 0); + if (buf1 == MAP_FAILED) + return -1; + if (mprotect (buf1 + 1 * page_size, page_size, PROT_NONE)) + return -1; + buf2 = mmap (0, 2 * page_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON, -1, 0); + if (buf2 == MAP_FAILED) + return -1; + if (mprotect (buf2 + page_size, page_size, PROT_NONE)) + return -1; + + memset (buf1, 0xa5, 1 * page_size); + memset (buf2, 0x5a, page_size); + + char *s1 = (char *) buf1; + char *s2 = (char *) buf2; + + size_t len; + size_t i, j; + len = 1 << 2; + for (i = 0, j = 1; i < len; i++, j += 23) + s1[i] = j; + + do_test (s1, s2, 10, 1 << 2); + + len = 1 << 4; + for (i = 0, j = 1; i < len; i++, j += 23) + s1[i] = j; + + do_test (s1, s2, 10, 1 << 4); + + return ret; +} -- 2.7.4