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Make _Thread_local more seamlessly working

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Justine Tunney 2022-07-10 08:27:50 -07:00
parent 5f4f6b0e69
commit 5fa77f1e8f
23 changed files with 217 additions and 283 deletions
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57
libc/runtime/enable_threads.c Normal file
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@ -0,0 +1,57 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/strace.internal.h"
#include "libc/nexgen32e/threaded.h"
#include "libc/runtime/runtime.h"
extern int __threadcalls_end[];
extern int __threadcalls_start[];
privileged void __enable_threads(void) {
if (__threaded) return;
STRACE("__enable_threads()");
__threaded = gettid();
__morph_begin();
/*
* _NOPL("__threadcalls", func)
*
* The big ugly macro above is used by Cosmopolitan Libc to unser
* locking primitive (e.g. flockfile, funlockfile) have zero impact on
* performance and binary size when threads aren't actually in play.
*
* we have this
*
* 0f 1f 05 b1 19 00 00 nopl func(%rip)
*
* we're going to turn it into this
*
* 67 67 e8 b1 19 00 00 addr32 addr32 call func
*
* This is cheap and fast because the big ugly macro stored in the
* binary the offsets of all the instructions we need to change.
*/
for (int *p = __threadcalls_start; p < __threadcalls_end; ++p) {
_base[*p + 0] = 0x67;
_base[*p + 1] = 0x67;
_base[*p + 2] = 0xe8;
}
__morph_end();
}