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Add atomics to chibicc

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This change also fixes #434 and makes the chibicc assembler better.
This commit is contained in:
Justine Tunney 2022-06-20 03:08:00 -07:00
parent 5ddf43332e
commit a988896048
21 changed files with 650 additions and 445 deletions
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7
libc/intrin/refcount.h
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@ -1,7 +0,0 @@
#ifndef COSMOPOLITAN_LIBC_INTRIN_REFCOUNT_H_
#define COSMOPOLITAN_LIBC_INTRIN_REFCOUNT_H_
#define _incref(x) __atomic_fetch_add(x, 1, __ATOMIC_RELAXED)
#define _decref(x) __atomic_sub_fetch(x, 1, __ATOMIC_SEQ_CST)
#endif /* COSMOPOLITAN_LIBC_INTRIN_REFCOUNT_H_ */

43
libc/intrin/wait0.c Normal file
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@ -0,0 +1,43 @@
/*-*- 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/bits/atomic.h"
#include "libc/calls/calls.h"
#include "libc/dce.h"
#include "libc/intrin/wait0.internal.h"
#include "libc/linux/futex.h"
/**
* Blocks until memory location becomes zero.
*
* This is intended to be used on the child thread id, which is updated
* by the clone() system call when a thread terminates. The purpose of
* this operation is to know when it's safe to munmap() a thread stack.
*/
void _wait0(int *ptid) {
int x;
for (;;) {
if (!(x = atomic_load_explicit(ptid, memory_order_relaxed))) {
break;
} else if (IsLinux()) {
LinuxFutexWait(ptid, x, 0);
} else {
sched_yield();
}
}
}

20
libc/intrin/wait0.internal.h
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@ -1,20 +1,10 @@
#ifndef COSMOPOLITAN_LIBC_INTRIN_WAIT0_H_
#define COSMOPOLITAN_LIBC_INTRIN_WAIT0_H_
#include "libc/bits/atomic.h"
#include "libc/calls/calls.h"
#include "libc/dce.h"
#include "libc/linux/futex.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
#define _wait0(ptid) \
do { \
int x; \
if (!(x = atomic_load_explicit(ptid, memory_order_relaxed))) { \
break; \
} else if (IsLinux()) { \
LinuxFutexWait(ptid, x, 0); \
} else { \
sched_yield(); \
} \
} while (1)
void _wait0(int *) hidden;
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_INTRIN_WAIT0_H_ */

10
libc/linux/futex.h
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@ -1,16 +1,16 @@
#ifndef COSMOPOLITAN_LIBC_LINUX_FUTEX_H_
#define COSMOPOLITAN_LIBC_LINUX_FUTEX_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
#include "libc/calls/struct/timespec.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
forceinline int LinuxFutexWait(void *addr, int expect,
struct timespec *timeout) {
int ax;
register void *r10 asm("r10") = timeout;
asm volatile("syscall"
asm volatile("mov\t%5,%%r10\n\t"
"syscall"
: "=a"(ax)
: "0"(202), "D"(addr), "S"(0), "d"(expect), "r"(r10)
: "rcx", "r11", "memory");
: "0"(202), "D"(addr), "S"(0), "d"(expect), "g"(timeout)
: "rcx", "r10", "r11", "memory");
return ax;
}