mirror of
https://github.com/jart/cosmopolitan.git
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b8a6a989c0
This change greatly reduces the number of modules that need to be compiled. The only issue right now is that sometimes when viewing symbol table entries, the aliased symbol is chosen.
122 lines
4.4 KiB
C
122 lines
4.4 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 2021 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/assert.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/str/str.h"
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#ifndef __aarch64__
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static inline const char *strchr_pure(const char *s, int c) {
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for (;; ++s) {
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if ((*s & 255) == (c & 255)) return s;
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if (!*s) return 0;
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}
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}
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#ifdef __x86_64__
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typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
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noasan static inline const char *strchr_sse(const char *s, unsigned char c) {
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unsigned k;
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unsigned m;
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xmm_t v, *p;
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xmm_t z = {0};
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xmm_t n = {c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c};
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k = (uintptr_t)s & 15;
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p = (const xmm_t *)((uintptr_t)s & -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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m = __builtin_ctzl(m);
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s = (const char *)p + m;
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if (c && !*s) s = 0;
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return s;
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}
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#endif
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static noasan inline const char *strchr_x64(const char *p, uint64_t c) {
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unsigned a, b;
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uint64_t w, x, y;
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for (c *= 0x0101010101010101;; p += 8) {
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w = (uint64_t)(255 & p[7]) << 070 | (uint64_t)(255 & p[6]) << 060 |
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(uint64_t)(255 & p[5]) << 050 | (uint64_t)(255 & p[4]) << 040 |
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(uint64_t)(255 & p[3]) << 030 | (uint64_t)(255 & p[2]) << 020 |
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(uint64_t)(255 & p[1]) << 010 | (uint64_t)(255 & p[0]) << 000;
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if ((x = ~(w ^ c) & ((w ^ c) - 0x0101010101010101) & 0x8080808080808080) |
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(y = ~w & (w - 0x0101010101010101) & 0x8080808080808080)) {
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if (x) {
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a = __builtin_ctzll(x);
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if (y) {
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b = __builtin_ctzll(y);
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if (a <= b) {
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return p + (a >> 3);
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} else {
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return 0;
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}
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} else {
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return p + (a >> 3);
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}
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} else {
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return 0;
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}
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}
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}
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}
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/**
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* Returns pointer to first instance of character.
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*
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* @param s is a NUL-terminated string
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* @param c is masked with 255 as byte to search for
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* @return pointer to first instance of c or NULL if not found
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* noting that if c is NUL we return pointer to terminator
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* @asyncsignalsafe
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* @vforksafe
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*/
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char *strchr(const char *s, int c) {
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#ifdef __x86_64__
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const char *r;
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if (X86_HAVE(SSE)) {
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if (IsAsan()) __asan_verify(s, 1);
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r = strchr_sse(s, c);
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} else {
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r = strchr_pure(s, c);
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}
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_unassert(!r || *r || !(c & 255));
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return (char *)r;
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#else
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char *r;
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for (c &= 255; (uintptr_t)s & 7; ++s) {
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if ((*s & 255) == c) return s;
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if (!*s) return NULL;
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}
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r = strchr_x64(s, c);
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_unassert(!r || *r || !c);
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return r;
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#endif
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}
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__strong_reference(strchr, index);
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#endif /* __aarch64__ */
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