mirror of
https://github.com/jart/cosmopolitan.git
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6f7d0cb1c3
This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
104 lines
4.4 KiB
C
104 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=8 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/assert.h"
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#include "libc/calls/asan.internal.h"
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#include "libc/calls/clock_gettime.internal.h"
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#include "libc/calls/state.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/calls/struct/timespec.internal.h"
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#include "libc/calls/struct/timeval.h"
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#include "libc/calls/syscall_support-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/fmt/conv.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/asmflag.h"
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#include "libc/intrin/bits.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/mem/alloca.h"
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#include "libc/nt/synchronization.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Returns nanosecond time.
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*
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* This is a high-precision timer that supports multiple definitions of
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* time. Among the more popular is CLOCK_MONOTONIC. This function has a
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* zero syscall implementation of that on modern x86.
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*
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* nowl l: 45𝑐 15𝑛𝑠
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* rdtsc l: 13𝑐 4𝑛𝑠
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* gettimeofday l: 44𝑐 14𝑛𝑠
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* clock_gettime l: 40𝑐 13𝑛𝑠
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* __clock_gettime l: 35𝑐 11𝑛𝑠
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* sys_clock_gettime l: 220𝑐 71𝑛𝑠
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*
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* @param clock can be CLOCK_REALTIME, CLOCK_MONOTONIC, etc.
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* @param ts is where the result is stored
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* @return 0 on success, or -1 w/ errno
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* @error EINVAL if clock isn't supported on this system
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* @see strftime(), gettimeofday()
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* @asyncsignalsafe
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*/
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int clock_gettime(int clock, struct timespec *ts) {
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int rc;
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if (clock == 127) {
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rc = einval(); // 127 is used by consts.sh to mean unsupported
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} else if (!ts || (IsAsan() && !__asan_is_valid_timespec(ts))) {
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rc = efault();
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} else {
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rc = __clock_gettime(clock, ts);
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}
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#if SYSDEBUG
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if (!__time_critical) {
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STRACE("clock_gettime(%s, [%s]) → %d% m", DescribeClockName(clock),
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DescribeTimespec(rc, ts), rc);
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}
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#endif
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return rc;
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}
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/**
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* Returns pointer to fastest clock_gettime().
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*/
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clock_gettime_f *__clock_gettime_get(bool *opt_out_isfast) {
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bool isfast;
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clock_gettime_f *res;
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if (IsLinux() && (res = __vdsosym("LINUX_2.6", "__vdso_clock_gettime"))) {
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isfast = true;
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} else if (IsXnu()) {
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isfast = false;
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res = sys_clock_gettime_xnu;
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} else if (IsWindows()) {
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isfast = true;
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res = sys_clock_gettime_nt;
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} else {
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isfast = false;
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res = sys_clock_gettime;
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}
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if (opt_out_isfast) {
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*opt_out_isfast = isfast;
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}
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return res;
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}
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hidden int __clock_gettime_init(int clockid, struct timespec *ts) {
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clock_gettime_f *gettime;
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__clock_gettime = gettime = __clock_gettime_get(0);
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return gettime(clockid, ts);
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}
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