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eeb20775d2
This will help C++ code that uses exceptions to be tinier. For example, this change shaves away 1000 lines of assembly code from LLVM's libcxx, which is 0.7% of all assembly instructions in the entire library.
70 lines
3.3 KiB
C
70 lines
3.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et 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/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/syscall-nt.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/str/str.h"
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#include "libc/sysv/errfuns.h"
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int sys_fadvise_netbsd(int, int, int64_t, int64_t, int) asm("sys_fadvise");
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/**
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* Drops hints to O/S about intended I/O behavior.
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*
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* It makes a huge difference. For example, when copying a large file,
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* it can stop the system from persisting GBs of useless memory content.
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*
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* @param len 0 means until end of file
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* @param advice can be MADV_SEQUENTIAL, MADV_RANDOM, etc.
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* @return 0 on success, or -1 w/ errno
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* @raise EBADF if `fd` isn't a valid file descriptor
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* @raise ESPIPE if `fd` refers to a pipe
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* @raise EINVAL if `advice` was invalid
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* @raise ENOSYS on XNU and OpenBSD
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*/
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int fadvise(int fd, uint64_t offset, uint64_t len, int advice) {
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int rc;
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if (IsLinux()) {
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rc = sys_fadvise(fd, offset, len, advice);
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} else if (IsFreebsd() || IsNetbsd()) {
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if (IsFreebsd()) {
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rc = sys_fadvise(fd, offset, len, advice);
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} else {
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rc = sys_fadvise_netbsd(fd, offset, offset, len, advice);
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}
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npassert(rc >= 0);
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if (rc) {
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errno = rc;
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rc = -1;
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}
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} else if (IsWindows()) {
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rc = sys_fadvise_nt(fd, offset, len, advice);
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} else {
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rc = enosys();
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}
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STRACE("fadvise(%d, %'lu, %'lu, %d) → %d% m", fd, offset, len, advice, rc);
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return rc;
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}
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__weak_reference(fadvise, fadvise64);
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