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| //===-- main.cpp ------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// This file deliberately uses low level linux-specific API for thread creation because:
// - instruction-stepping over thread creation using higher-level functions was very slow
// - it was also unreliable due to single-stepping bugs unrelated to this test
// - some threading libraries do not create or destroy threads when we would expect them to
#include <sched.h>
#include <atomic>
#include <cstdio>
enum { STACK_SIZE = 0x2000 };
static uint8_t child_stack[STACK_SIZE];
pid_t child_tid;
std::atomic<bool> flag(false);
int thread_main(void *)
{
while (! flag) // Make sure the thread does not exit prematurely
;
return 0;
}
int main ()
{
int ret = clone(thread_main,
child_stack + STACK_SIZE/2, // Don't care whether the stack grows up or down,
// just point to the middle
CLONE_CHILD_CLEARTID | CLONE_FILES | CLONE_FS | CLONE_PARENT_SETTID |
CLONE_SIGHAND | CLONE_SYSVSEM | CLONE_THREAD | CLONE_VM,
nullptr, // thread_main argument
&child_tid);
if (ret == -1)
{
perror("clone");
return 1;
}
flag = true;
return 0;
}
|