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// Copyright (C) 2012-2022 Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// GCC is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3, or (at your option)
// any later version.
// GCC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#include <cxxabi.h>
#include <cstdlib>
#include <new>
#include "bits/gthr.h"
#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif
// Simplify it a little for this file.
#ifndef _GLIBCXX_CDTOR_CALLABI
# define _GLIBCXX_CDTOR_CALLABI
#endif
#if _GLIBCXX_HAVE___CXA_THREAD_ATEXIT
// Libc provides __cxa_thread_atexit definition.
#elif _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL
extern "C" int __cxa_thread_atexit_impl (void (_GLIBCXX_CDTOR_CALLABI *func) (void *),
void *arg, void *d);
extern "C" int
__cxxabiv1::__cxa_thread_atexit (void (_GLIBCXX_CDTOR_CALLABI *dtor)(void *),
void *obj, void *dso_handle)
_GLIBCXX_NOTHROW
{
return __cxa_thread_atexit_impl (dtor, obj, dso_handle);
}
#else /* _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL */
namespace {
// One element in a singly-linked stack of cleanups.
struct elt
{
void (_GLIBCXX_CDTOR_CALLABI *destructor)(void *);
void *object;
elt *next;
#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
HMODULE dll;
#endif
};
// Keep a per-thread list of cleanups in gthread_key storage.
__gthread_key_t key;
// But also support non-threaded mode.
elt *single_thread;
// Run the specified stack of cleanups.
void run (void *p)
{
elt *e = static_cast<elt*>(p);
while (e)
{
elt *old_e = e;
e->destructor (e->object);
#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
/* Decrement DLL count */
if (e->dll)
FreeLibrary (e->dll);
#endif
e = e->next;
delete (old_e);
}
}
// Run the stack of cleanups for the current thread.
void run ()
{
void *e;
if (__gthread_active_p ())
{
e = __gthread_getspecific (key);
__gthread_setspecific (key, NULL);
}
else
{
e = single_thread;
single_thread = NULL;
}
run (e);
}
// Initialize the key for the cleanup stack. We use a static local for
// key init/delete rather than atexit so that delete is run on dlclose.
void key_init() {
struct key_s {
key_s() { __gthread_key_create (&key, run); }
~key_s() { __gthread_key_delete (key); }
};
static key_s ks;
// Also make sure the destructors are run by std::exit.
// FIXME TLS cleanups should run before static cleanups and atexit
// cleanups.
std::atexit (run);
}
}
extern "C" int
__cxxabiv1::__cxa_thread_atexit (void (_GLIBCXX_CDTOR_CALLABI *dtor)(void *),
void *obj, void */*dso_handle*/)
_GLIBCXX_NOTHROW
{
// Do this initialization once.
if (__gthread_active_p ())
{
// When threads are active use __gthread_once.
static __gthread_once_t once = __GTHREAD_ONCE_INIT;
__gthread_once (&once, key_init);
}
else
{
// And when threads aren't active use a static local guard.
static bool queued;
if (!queued)
{
queued = true;
std::atexit (run);
}
}
elt *first;
if (__gthread_active_p ())
first = static_cast<elt*>(__gthread_getspecific (key));
else
first = single_thread;
elt *new_elt = new (std::nothrow) elt;
if (!new_elt)
return -1;
new_elt->destructor = dtor;
new_elt->object = obj;
new_elt->next = first;
#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
/* Store the DLL address for a later call to FreeLibrary in new_elt and
increment DLL load count. This blocks the unloading of the DLL
before the thread-local dtors have been called. This does NOT help
if FreeLibrary/dlclose is called in excess. */
GetModuleHandleExW (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
(LPCWSTR) dtor, &new_elt->dll);
#endif
if (__gthread_active_p ())
__gthread_setspecific (key, new_elt);
else
single_thread = new_elt;
return 0;
}
#endif /* _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL */
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