mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 15:03:34 +00:00
28997f3acb
This program usually runs once at the begininng of each GNU Make invocation. It generates an o//depend file with 170,000 lines of Makefile code to define source -> headers relationships. This change makes that take 650 milliseconds rather than 1,100ms by improving the performance of strstr(), using longsort(), plus migrating to the new append library.
70 lines
3.5 KiB
C
70 lines
3.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
|
│ Copyright 2020 Justine Alexandra Roberts Tunney │
|
|
│ │
|
|
│ Permission to use, copy, modify, and/or distribute this software for │
|
|
│ any purpose with or without fee is hereby granted, provided that the │
|
|
│ above copyright notice and this permission notice appear in all copies. │
|
|
│ │
|
|
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
|
|
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
|
|
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
|
|
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
|
|
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
|
|
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
|
|
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
|
|
│ PERFORMANCE OF THIS SOFTWARE. │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "libc/dce.h"
|
|
#include "libc/intrin/asan.internal.h"
|
|
#include "libc/str/str.h"
|
|
|
|
typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
|
|
|
|
/**
|
|
* Searches for substring.
|
|
*
|
|
* @param haystack is the search area, as a NUL-terminated string
|
|
* @param needle is the desired substring, also NUL-terminated
|
|
* @return pointer to first substring within haystack, or NULL
|
|
* @note this implementation goes fast in practice but isn't hardened
|
|
* against pathological cases, and therefore shouldn't be used on
|
|
* untrustworthy data
|
|
* @asyncsignalsafe
|
|
* @see memmem()
|
|
*/
|
|
noasan char *strstr(const char *haystack, const char *needle) {
|
|
xmm_t *p;
|
|
size_t i;
|
|
unsigned k, m;
|
|
xmm_t v, n, z = {0};
|
|
if (IsAsan()) __asan_verify(needle, 1);
|
|
if (IsAsan()) __asan_verify(haystack, 1);
|
|
if (haystack == needle || !*needle) return haystack;
|
|
n = (xmm_t){*needle, *needle, *needle, *needle, *needle, *needle,
|
|
*needle, *needle, *needle, *needle, *needle, *needle,
|
|
*needle, *needle, *needle, *needle};
|
|
for (;;) {
|
|
k = (uintptr_t)haystack & 15;
|
|
p = (const xmm_t *)((uintptr_t)haystack & -16);
|
|
v = *p;
|
|
m = __builtin_ia32_pmovmskb128(__builtin_ia32_pcmpeqb128(v, z) |
|
|
__builtin_ia32_pcmpeqb128(v, n));
|
|
m >>= k;
|
|
m <<= k;
|
|
while (!m) {
|
|
v = *++p;
|
|
m = __builtin_ia32_pmovmskb128(__builtin_ia32_pcmpeqb128(v, z) |
|
|
__builtin_ia32_pcmpeqb128(v, n));
|
|
}
|
|
haystack = (const char *)p + __builtin_ctzl(m);
|
|
for (i = 0;; ++i) {
|
|
if (!needle[i]) return (/*unconst*/ char *)haystack;
|
|
if (!haystack[i]) break;
|
|
if (needle[i] != haystack[i]) break;
|
|
}
|
|
if (!*haystack++) break;
|
|
}
|
|
return 0;
|
|
}
|