1 | /* |
2 | * Copyright 2013-present Facebook, Inc. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | |
17 | #pragma once |
18 | |
19 | #include <exception> |
20 | |
21 | #if !defined(FOLLY_FORCE_EXCEPTION_COUNT_USE_STD) && \ |
22 | (defined(__GNUG__) || defined(__clang__)) |
23 | #define FOLLY_EXCEPTION_COUNT_USE_CXA_GET_GLOBALS |
24 | namespace __cxxabiv1 { |
25 | // forward declaration (originally defined in unwind-cxx.h from from libstdc++) |
26 | struct __cxa_eh_globals; |
27 | // declared in cxxabi.h from libstdc++-v3 |
28 | extern "C" __cxa_eh_globals* __cxa_get_globals() noexcept; |
29 | } // namespace __cxxabiv1 |
30 | #elif defined(_MSC_VER) && (_MSC_VER >= 1400) && \ |
31 | (_MSC_VER < 1900) // MSVC++ 8.0 or greater |
32 | #define FOLLY_EXCEPTION_COUNT_USE_GETPTD |
33 | // forward declaration (originally defined in mtdll.h from MSVCRT) |
34 | struct _tiddata; |
35 | extern "C" _tiddata* _getptd(); // declared in mtdll.h from MSVCRT |
36 | #elif defined(FOLLY_FORCE_EXCEPTION_COUNT_USE_STD) || \ |
37 | (defined(_MSC_VER) && (_MSC_VER >= 1900)) // MSVC++ 2015 |
38 | #define FOLLY_EXCEPTION_COUNT_USE_STD |
39 | #else |
40 | // Raise an error when trying to use this on unsupported platforms. |
41 | #error "Unsupported platform, don't include this header." |
42 | #endif |
43 | |
44 | namespace folly { |
45 | |
46 | /** |
47 | * Returns the number of uncaught exceptions. |
48 | * |
49 | * This function is based on Evgeny Panasyuk's implementation from here: |
50 | * http://fburl.com/15190026 |
51 | */ |
52 | inline int uncaught_exceptions() noexcept { |
53 | #if defined(FOLLY_EXCEPTION_COUNT_USE_CXA_GET_GLOBALS) |
54 | // __cxa_get_globals returns a __cxa_eh_globals* (defined in unwind-cxx.h). |
55 | // The offset below returns __cxa_eh_globals::uncaughtExceptions. |
56 | return *(reinterpret_cast<unsigned int*>( |
57 | static_cast<char*>(static_cast<void*>(__cxxabiv1::__cxa_get_globals())) + |
58 | sizeof(void*))); |
59 | #elif defined(FOLLY_EXCEPTION_COUNT_USE_GETPTD) |
60 | // _getptd() returns a _tiddata* (defined in mtdll.h). |
61 | // The offset below returns _tiddata::_ProcessingThrow. |
62 | return *(reinterpret_cast<int*>( |
63 | static_cast<char*>(static_cast<void*>(_getptd())) + sizeof(void*) * 28 + |
64 | 0x4 * 8)); |
65 | #elif defined(FOLLY_EXCEPTION_COUNT_USE_STD) |
66 | return std::uncaught_exceptions(); |
67 | #endif |
68 | } |
69 | |
70 | } // namespace folly |
71 | |