mirror of
https://github.com/jart/cosmopolitan.git
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7e0a09feec
This change ports APE Loader to Linux AARCH64, so that Raspberry Pi users can run programs like redbean, without the executable needing to modify itself. Progress has also slipped into this change on the issue of making progress better conforming to user expectations and industry standards regarding which symbols we're allowed to declare
84 lines
3.7 KiB
C
84 lines
3.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/str/str.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
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/**
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* Searches for substring.
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*
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* @param haystack is the search area, as a NUL-terminated string
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* @param needle is the desired substring, also NUL-terminated
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* @return pointer to first substring within haystack, or NULL
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* @note this implementation goes fast in practice but isn't hardened
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* against pathological cases, and therefore shouldn't be used on
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* untrustworthy data
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* @asyncsignalsafe
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* @see strcasestr()
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* @see memmem()
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*/
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dontasan char *strstr(const char *haystack, const char *needle) {
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#ifdef __x86_64__
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xmm_t *p;
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size_t i;
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unsigned k, m;
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xmm_t v, n, z = {0};
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if (IsAsan()) __asan_verify(needle, 1);
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if (IsAsan()) __asan_verify(haystack, 1);
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if (haystack == needle || !*needle) return haystack;
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n = (xmm_t){*needle, *needle, *needle, *needle, *needle, *needle,
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*needle, *needle, *needle, *needle, *needle, *needle,
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*needle, *needle, *needle, *needle};
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for (;;) {
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k = (uintptr_t)haystack & 15;
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p = (const xmm_t *)((uintptr_t)haystack & -16);
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v = *p;
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m = __builtin_ia32_pmovmskb128((v == z) | (v == n));
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m >>= k;
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m <<= k;
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while (!m) {
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v = *++p;
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m = __builtin_ia32_pmovmskb128((v == z) | (v == n));
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}
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haystack = (const char *)p + __builtin_ctzl(m);
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for (i = 0;; ++i) {
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if (!needle[i]) return (/*unconst*/ char *)haystack;
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if (!haystack[i]) break;
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if (needle[i] != haystack[i]) break;
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}
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if (!*haystack++) break;
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}
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return 0;
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#else
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size_t i;
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unsigned k, m;
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if (haystack == needle || !*needle) return haystack;
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for (;;) {
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for (i = 0;; ++i) {
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if (!needle[i]) return (/*unconst*/ char *)haystack;
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if (!haystack[i]) break;
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if (needle[i] != haystack[i]) break;
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}
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if (!*haystack++) break;
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}
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return 0;
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#endif
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}
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