libc/src/stdlib/exit_handler.h

   1 //===-- Implementation header for exit_handler ------------------*- C++ -*-===//
   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 #ifndef LLVM_LIBC_SRC_STDLIB_EXIT_HANDLER_H
  10 #define LLVM_LIBC_SRC_STDLIB_EXIT_HANDLER_H
  11
  12 #include "src/__support/CPP/mutex.h" // lock_guard
  13 #include "src/__support/blockstore.h"
  14 #include "src/__support/common.h"
  15 #include "src/__support/fixedvector.h"
  16 #include "src/__support/macros/config.h"
  17 #include "src/__support/threads/mutex.h"
  18
  19 namespace LIBC_NAMESPACE_DECL {
  20
  21 using AtExitCallback = void(void *);
  22 using StdCAtExitCallback = void(void);
  23 constexpr size_t CALLBACK_LIST_SIZE_FOR_TESTS = 1024;
  24
  25 struct AtExitUnit {
  26   AtExitCallback *callback = nullptr;
  27   void *payload = nullptr;
  28   LIBC_INLINE constexpr AtExitUnit() = default;
  29   LIBC_INLINE constexpr AtExitUnit(AtExitCallback *c, void *p)
  30       : callback(c), payload(p) {}
  31 };
  32
  33 #if defined(LIBC_TARGET_ARCH_IS_GPU)
  34 using ExitCallbackList = FixedVector<AtExitUnit, 64>;
  35 #elif defined(LIBC_COPT_PUBLIC_PACKAGING)
  36 using ExitCallbackList = ReverseOrderBlockStore<AtExitUnit, 32>;
  37 #else
  38 using ExitCallbackList = FixedVector<AtExitUnit, CALLBACK_LIST_SIZE_FOR_TESTS>;
  39 #endif
  40
  41 // This is handled by the 'atexit' implementation and shared by 'at_quick_exit'.
  42 extern Mutex handler_list_mtx;
  43
  44 LIBC_INLINE void stdc_at_exit_func(void *payload) {
  45   reinterpret_cast<StdCAtExitCallback *>(payload)();
  46 }
  47
  48 LIBC_INLINE void call_exit_callbacks(ExitCallbackList &callbacks) {
  49   handler_list_mtx.lock();
  50   while (!callbacks.empty()) {
  51     AtExitUnit &unit = callbacks.back();
  52     callbacks.pop_back();
  53     handler_list_mtx.unlock();
  54     unit.callback(unit.payload);
  55     handler_list_mtx.lock();
  56   }
  57   ExitCallbackList::destroy(&callbacks);
  58 }
  59
  60 LIBC_INLINE int add_atexit_unit(ExitCallbackList &callbacks,
  61                                 const AtExitUnit &unit) {
  62   cpp::lock_guard lock(handler_list_mtx);
  63   if (callbacks.push_back(unit))
  64     return 0;
  65   return -1;
  66 }
  67
  68 } // namespace LIBC_NAMESPACE_DECL
  69
  70 #endif // LLVM_LIBC_SRC_STDLIB_EXIT_HANDLER_H