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https://github.com/jart/cosmopolitan.git
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85 lines
3.7 KiB
C
85 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 et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2023 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/calls/calls.h"
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#include "libc/intrin/x86.h"
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#include "libc/runtime/runtime.h"
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#include "third_party/getopt/getopt.internal.h"
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/**
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* @fileoverview Command for printing `-march=native` flags.
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*
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* In recent years (2023) compilers have decided to remove support for
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* the `-march=native` flag, even on x86. That's unfortunate, since as
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* we can see below, grokking all the various microarchitecture is not
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* something a compiler should reasonably expect from users especially
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* not for a flag as important as this one, which can have a night and
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* day impact for apps that do scientific computing.
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*
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* This is a tiny program, that makes it easy for shell scripts to get
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* these flags.
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*/
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#define VERSION \
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"-march=native flag printer v0.2\n" \
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"copyright 2024 justine alexandra roberts tunney\n"
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#define USAGE \
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"usage: march-native [-hvc]\n" \
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" -h show help\n" \
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" -v show version\n" \
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" -c assume we're using clang (not gcc)\n"
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static bool isclang;
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static void GetOpts(int argc, char *argv[]) {
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int opt;
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while ((opt = getopt(argc, argv, "hvc")) != -1) {
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switch (opt) {
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case 'c':
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isclang = true;
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break;
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case 'v':
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tinyprint(1, VERSION, NULL);
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exit(0);
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case 'h':
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tinyprint(1, VERSION, USAGE, NULL);
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exit(0);
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default:
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tinyprint(2, VERSION, USAGE, NULL);
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exit(1);
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}
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}
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}
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static void Puts(const char *s) {
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tinyprint(1, s, "\n", NULL);
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}
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int main(int argc, char *argv[]) {
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GetOpts(argc, argv);
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#ifdef __x86_64__
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const char *march;
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if ((march = __cpu_march(__cpu_model.__cpu_subtype)))
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tinyprint(1, "-march=", march, "\n", NULL);
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#elif defined(__aarch64__)
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// TODO(jart): How can we determine CPU features on AARCH64?
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#else
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// otherwise do nothing (it's usually best)
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#endif
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}
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