1 //===-- Implementation of atexit ------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "src/stdlib/atexit.h"
10 #include "src/__support/CPP/vector.h"
11 #include "src/__support/common.h"
12 #include "src/__support/threads/mutex.h"
13 
14 namespace __llvm_libc {
15 
16 namespace {
17 
18 Mutex handler_list_mtx(false, false, false);
19 
20 // TOOD should we make cpp::vector like llvm::SmallVector<T, N> where it will
21 // allocate at least N before needing dynamic allocation?
22 static cpp::vector<void (*)(void)> handlers;
23 
24 } // namespace
25 
26 namespace internal {
27 
28 void call_exit_handlers() {
29   handler_list_mtx.lock();
30   // TODO: implement rbegin() + rend() for cpp::vector
31   for (int i = handlers.size() - 1; i >= 0; i--) {
32     handler_list_mtx.unlock();
33     handlers[i]();
34     handler_list_mtx.lock();
35   }
36 }
37 
38 } // namespace internal
39 
40 LLVM_LIBC_FUNCTION(int, atexit, (void (*function)())) {
41   handler_list_mtx.lock();
42   handlers.push_back(function);
43   handler_list_mtx.unlock();
44   return 0;
45 }
46 
47 } // namespace __llvm_libc
48