Summary:
Found with readability-container-size-empty
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Pull Request resolved: https://github.com/facebook/folly/pull/1293

Reviewed By: markisaa

Differential Revision: D19241094

Pulled By: yfeldblum

fbshipit-source-id: 9362e8dc5dc1458fcd2b27c11ce81eafe674bcd2

Summary: [Folly] Apply `clang-format` in places.

Reviewed By: markisaa

Differential Revision: D19249033

fbshipit-source-id: 1a768eea013112ee5cd9d8b78114927fd6d6db04

Summary: [Folly] Apply python formatting to a few unsynced places in some `.pyi` files.

Reviewed By: markisaa

Differential Revision: D19249037

fbshipit-source-id: 6b14c5fedbee0f25a4b0fdfdd0f157e62a95a766

Reviewed By: yfeldblum

Differential Revision: D19235483

fbshipit-source-id: 5caea4efb3e811f78f1be3f05adc315bccb0fc0d

Summary:
Found with modernize-use-equals-default
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Pull Request resolved: https://github.com/facebook/folly/pull/1291

Reviewed By: markisaa

Differential Revision: D19229643

Pulled By: yfeldblum

fbshipit-source-id: 69f0bd4f55ea5a3697ab176aab80683b99b4e11c

Summary: [Folly] Return spelled default ctor in `AlignedSysAllocator` - it is necessary until gcc7.

Reviewed By: LeeHowes

Differential Revision: D19235864

fbshipit-source-id: fd0e9c33283e8b646aff56efb10d8e2a8c05e293

Summary:
I'd like to enable UBSAN's unsigned-integer-overflow check. It's not an undefined behavior, but it is often unintentional.

This adds suppressions to folly/hash where unsigned-integer-overflow is expected due the the nature of operations.

Reviewed By: yfeldblum

Differential Revision: D19217819

fbshipit-source-id: 1a468018823e0ac1d01c3ae889e38e9d42bdd8b7

Summary: [Folly] Cut some outdated lines in docs and comments which refer to no-longer supported versions of gcc.

Reviewed By: Orvid

Differential Revision: D19229059

fbshipit-source-id: c8abb81c292091339622e9cc3d4e5fd3cd6459b4

Summary:
libcxx does not have strcmp or strlen as constexpr.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Pull Request resolved: https://github.com/facebook/folly/pull/1288

Reviewed By: Orvid

Differential Revision: D19226813

Pulled By: yfeldblum

fbshipit-source-id: 4b5de4f923f4d7871c059af54eb7d375f344f48a

Summary: [Folly] Use `getCurrentThreadName()` in `EventBaseTestLib.h` v.s. using pthread directly.

Reviewed By: Orvid

Differential Revision: D19226856

fbshipit-source-id: 90f825ab0fc186a896cd63c425e55153daa0fefd

Summary: [Folly] Update a comment in `CacheLocalityBenchmark.cpp` to refer to the direct function used for fetching the thread-id.

Reviewed By: Orvid

Differential Revision: D19226855

fbshipit-source-id: 8cf203daa7b3fbc00e387dca881be7f9ce47af95

Summary:
[Folly] Use `std::thread` in `AtomicHashMapTest.cpp` instead of using the pthread API.

In general in normal C++ code, prefer C++ standard library facilities over C facilities.

Reviewed By: Orvid

Differential Revision: D19226850

fbshipit-source-id: 7edc5fca25266b48ab3e8c8829708594d7563409

Summary:
- EventBaseTestLib.cpp file was moved to EventBaseTestLibProvider.cpp
  in Differential Revision: D19001877.
- Change CMakeLists.txt to specify EventBaseTestLibProvider.cpp so that
  CMake does not fail at configure time due to EventBaseTestLib.cpp not
  existing in the source tree.
Pull Request resolved: https://github.com/facebook/folly/pull/1284

Reviewed By: markisaa

Differential Revision: D19226798

Pulled By: yfeldblum

fbshipit-source-id: 45a5e5ca03a52897a6f8f711761bf78ef386e6f6

Summary: [Folly] Fix typo in `clang-format` control.

Reviewed By: markisaa

Differential Revision: D19224383

fbshipit-source-id: 1d153fb4eaead422d93c235e40163b8ae855d13a

Summary: It's a read-only interface.

Reviewed By: philippv, luciang

Differential Revision: D19199710

fbshipit-source-id: 5e900edd35640cded45e6376eb0b81b9036bd792

Summary: It can be useful for diagnostics to print the stack traces of thrown exceptions that are not yet handled, for example if a fatal error happens during unwinding.

Reviewed By: philippv, luciang

Differential Revision: D19191089

fbshipit-source-id: dae8cc0a095570bfe7d6c4c7ef2b5dc08aa9f1f9

Summary: [Folly] Let `AtFork` accept ptr-to-`const` handle rather than requiring only ptr-to-non-`const`.

Reviewed By: luciang

Differential Revision: D19208255

fbshipit-source-id: c7a6ab42b7b652ebc4ea6465f80db37ef1d155df

Summary: [Folly] Rename `object` to `handle` in `AtFork` since it is used opaquely.

Reviewed By: luciang

Differential Revision: D19208246

fbshipit-source-id: 3fc23e85b64f911f8e172a22f7e7080952d4dfe9

Summary: [Folly] Register with `AtFork` without an object in `BufferedRandomDevice`, since no object is actually needed and since it is possible for the object passed in to be destroyed.

Reviewed By: luciang

Differential Revision: D19207385

fbshipit-source-id: 7c0e2793d9b438e576bf26bc3b3b459b372aec6d

Summary: [Folly] Let `AtFork` ignore unregistration of `nullptr` objects - i.e., let `nullptr` objects be the way of signaling immunity from unregistration.

Reviewed By: luciang

Differential Revision: D19207380

fbshipit-source-id: 6dfee52bf815fc257697fb89d67f69cede0f39f6

Summary:
[Folly] Define `to_narrow` in terms of implicit conversion to take advantage of ubsan's truncation checks.

Note that integer truncation is not undefined behavior per se but is commonly unintended, so ubsan checks for it. Uses of `to_narrow` should not be subject to truncation; wherever truncation is anticipated, better to use an explicit conversion with a named destination type.

Requires suppressing `-Wconversion` around the implicit conversion to avoid extraneous warnings and errors when the compiler detects narrowing implicit conversions. Since `to_narrow` models explicit conversion while merely being defined in terms of implicit conversion, it is already anticipated by all users that a narrowing conversion may occur; the warning is there to inform users only about unanticipated cases.

Reviewed By: luciang

Differential Revision: D19201430

fbshipit-source-id: b3739d3d9aa05e95f7b3e4dff54e719691c1f04c

Summary: [Folly] Mark `co_error` as `final`.

Reviewed By: lewissbaker

Differential Revision: D19173904

fbshipit-source-id: 3dedf9a27629dd495d7097d00566a92753b65778

Summary: [Folly] Forbid `co_error` with empty `exception_wrapper`.

Reviewed By: lewissbaker

Differential Revision: D19172250

fbshipit-source-id: 5ffa7502eb97b6a084be3112b17f29bad2d96a0f

Summary:
Found with modernize-loop-convert
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Pull Request resolved: https://github.com/facebook/folly/pull/1260

Reviewed By: markisaa

Differential Revision: D18747876

Pulled By: yfeldblum

fbshipit-source-id: f2b19654bb3fcbb75b1210edeef536c88f3052d1

Summary: [Folly] Let `PriorityUnboundedQueueSet` align its queues, which have extended alignment, even when `std::allocator` does not honor extended alignment.

Reviewed By: magedm

Differential Revision: D19174993

fbshipit-source-id: 0bc0d75c6d239c97b6e1c7380bffff0363008e16

Summary: [Folly] Let AlignedSysAllocator consider the natural or specified alignment of the type for which memory is being allocated, rather than only considering a constant or fixed alignment.

Reviewed By: nbronson

Differential Revision: D19174932

fbshipit-source-id: e8ed0fbaf30d285cadd061d0fe5d69fcbb16f9e2

Summary: The tagged/specific exception variant of thenError and deferError propagate interrupts where currently the untagged variant of thenError does not. As far as I can tell this was an oversight. This makes untagged thenError behave as expected.

Reviewed By: yfeldblum, mpark

Differential Revision: D18643814

fbshipit-source-id: 42688c4363de2f6b027766b19276b2e8ec6a48a8

Summary: [Folly] Remove spelled default ctor in `AlignedSysAllocator`, which was needed only for gcc49.

Reviewed By: aary

Differential Revision: D19171223

fbshipit-source-id: ee42f6ac188dc896519537870353116c0dfd3acd

Summary:
[Folly] Extended constructibility for `co_error` - constructible from everything `exception_wrapper` is constructible from, but not default-constructible. This permits:

```lang=c++
co_yield folly::coro::co_error(std::runtime_error("foo"));
```

Reviewed By: lewissbaker

Differential Revision: D19172210

fbshipit-source-id: df21c4f2a15ad2286e7cb34aae7c1be05e797a94

Summary: [Folly] Avoid a too-large pointer literal in StlVectorTest, keeping the literal value divisible by 8 to avoid ubsan violations.

Reviewed By: igorsugak

Differential Revision: D19170467

fbshipit-source-id: 2c93d2b3d9f7515761668d3364c4b8b5093a6145

Summary: [Folly] Only use `explicit` copy-ctor in `to_narrow` with C++17 and higher, since C++17 introduces mandatory copy elision and the technique here relies on mandatory copy elision.

Differential Revision: D19175384

fbshipit-source-id: 9d3234a71b1b5e4f31d14137e42dbf3a73c79b2e

Summary:
Fixing warning exposed by -Wpointer-bool-conversion

```
 folly/container/test/F14MapTest.cpp:1370:35: error: address of function 'Tracked<0>::counts' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
            << "key_type ops " << Tracked<0>::counts << ", mapped_type ops "
                               ~~ ^~~~~~~~~~~~~~~~~~
folly/container/test/F14MapTest.cpp:1370:35: note: prefix with the address-of operator to silence this warning
            << "key_type ops " << Tracked<0>::counts << ", mapped_type ops "
                                  ^
                                  &
folly/container/test/F14MapTest.cpp:1371:16: error: address of function 'Tracked<1>::counts' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
            << Tracked<1>::counts;
            ~~ ^~~~~~~~~~~~~~~~~~
folly/container/test/F14MapTest.cpp:1371:16: note: prefix with the address-of operator to silence this warning
            << Tracked<1>::counts;
               ^
               &
2 errors generated.

Reviewed By: yfeldblum

Differential Revision: D19131722

fbshipit-source-id: 9db48848ab5d68bc73ab0d6a4ef557d0db05414e

Summary: [Folly] Extract `has_extended_alignemnt`.

Reviewed By: aary

Differential Revision: D19149753

fbshipit-source-id: c6fa5cf2adcab732a21fbb31ab8ab60e978b9bc8

Summary: [Folly] Canonical impl of futures `Core::removeStaleDependents` using std algorithms.

Reviewed By: leikahing, igorsugak

Differential Revision: D19167292

fbshipit-source-id: 702fdf07bdcc295ed990d2c02cd3380ea81694a2

Summary:
In cores we're only interested in the ElfPhdrs (and there generally
aren't any sections), so apart from some asserts, the code already
does everything we need.

Reviewed By: paulbiss

Differential Revision: D19161810

fbshipit-source-id: fe6e2f34413d61067156858fc652ffffd910433c

Summary:
Exposed by UBSAN's misaligned-pointer-use:
```lang=bash
> folly/test/stl_tests/StlVectorTest.cpp:544:12: runtime error: upcast of misaligned address 0x0000feebdaed for type 'DataTracker<false>', which requires 8 byte alignment
> 0x0000feebdaed: note: pointer points here
> <memory cannot be printed>
>     #0 0x6c9b93 in DataTracker<false>::~DataTracker() folly/test/stl_tests/StlVectorTest.cpp:544
>     #1 0x6c94fe in Data<0u, 0ul>::~Data() folly/test/stl_tests/StlVectorTest.cpp:605
>     #2 0xcc5f93 in void test_iteratorInsertionN2<folly::fbvector<Data<0u, 0ul>, std::allocator<Data<0u, 0ul> > > >(std::integral_constant<bool, true>) folly/test/stl_tests/StlVectorTest.cpp:2422
>     #3 0x5c9bac in void test_iteratorInsertionN3<folly::fbvector<Data<0u, 0ul>, std::allocator<Data<0u, 0ul> > > >() folly/test/stl_tests/StlVectorTest.cpp:2422
>     #4 0x5c67bd in FBVector_iteratorInsertionN_Test::TestBody() folly/test/stl_tests/StlVectorTest.cpp:2422
>     #5 0x7f9c4e5316c9 in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) xplat/third-party/gmock/googletest-1.8.0/googletest/src/gtest.cc:2464
>     #6 0x7f9c4e530dcc in testing::Test::Run() xplat/third-party/gmock/googletest-1.8.0/googletest/src/gtest.cc:2480
>     #7 0x7f9c4e5350a0 in testing::TestInfo::Run() xplat/third-party/gmock/googletest-1.8.0/googletest/src/gtest.cc:2662
>     #8 0x7f9c4e539408 in testing::TestCase::Run() xplat/third-party/gmock/googletest-1.8.0/googletest/src/gtest.cc:2780
>     #9 0x7f9c4e55a672 in testing::internal::UnitTestImpl::RunAllTests() xplat/third-party/gmock/googletest-1.8.0/googletest/src/gtest.cc:4655
>     #10 0x7f9c4e5595de in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) xplat/third-party/gmock/googletest-1.8.0/googletest/src/gtest.cc:2464
>     #11 0x7f9c4e558b72 in testing::UnitTest::Run() xplat/third-party/gmock/googletest-1.8.0/googletest/src/gtest.cc:4263
>     #12 0x6591f3 in RUN_ALL_TESTS() buck-out/cells/fbsource/gen/xplat/third-party/gmock/gtest_headers#header-mode-symlink-tree-with-header-map,headers/gtest/gtest.h:2247
>     #13 0x659139 in main folly/test/stl_tests/StlVectorTest.cpp:3074
>     #14 0x7f9c4c75b1a5 in __libc_start_main /home/engshare/third-party2/glibc/2.26/src/glibc-2.26/csu/libc-start.c:308:16
>     #15 0x4de029 in _start /home/engshare/third-party2/glibc/2.26/src/glibc-2.26/sysdeps/x86_64/start.S:120
>
> SUMMARY: UndefinedBehaviorSanitizer: misaligned-pointer-use folly/test/stl_tests/StlVectorTest.cpp:544:12
```

Make the crafted pointer address aligned.

Reviewed By: Gownta

Differential Revision: D19166262

fbshipit-source-id: f766656d031079350838598b135275bdbc047642

Summary:
Not sure if there is any predefined cross-platform macro that I can use the
detect the build mode.

Reviewed By: luciang

Differential Revision: D19161841

fbshipit-source-id: 49dd12096ab20bbcaada566f2ad854a9ea340c11

Summary: [Folly] Canonical implementation of `IoUringBackend::NotAvailable` - need to export exceptions since they are the most likely use-case for RTTI and can just bring the base class's ctors into scope.

Differential Revision: D19154080

fbshipit-source-id: efaf9440a5ec3d78201448160efe4b8893314956

Reviewed By: yfeldblum, lewissbaker

Differential Revision: D19156701

fbshipit-source-id: 80bd8b7fc6dfde71756411342e5f4eb912150f06

Summary:
Exposed by UBSAN's unsigned-integer-overflow:
```
> folly/experimental/observer/detail/Core.cpp:179:9: runtime error: unsigned integer overflow: 0 - 1 cannot be represented in type 'size_t' (aka 'unsigned long')
>     #0 0x7f605837dfea in folly::observer_detail::Core::removeStaleDependents()::$_4::operator()(std::vector<std::weak_ptr<folly::observer_detail::Core>, std::allocator<std::weak_ptr<folly::observer_detail::Core> > >&) const folly/experimental/observer/detail/Core.cpp:179
>     #1 0x7f6058344b0c in auto folly::SynchronizedBase<folly::Synchronized<std::vector<std::weak_ptr<folly::observer_detail::Core>, std::allocator<std::weak_ptr<folly::observer_detail::Core> > >, folly::SharedMutexImpl<false, void, std::atomic, false, false> >, (folly::detail::MutexLevel)1>::withWLock<folly::observer_detail::Core::removeStaleDependents()::$_4>(folly::observer_detail::Core::removeStaleDependents()::$_4&&) folly/Synchronized.h:210
>     #2 0x7f6058344917 in folly::observer_detail::Core::removeStaleDependents() folly/experimental/observer/detail/Core.cpp:174
>     #3 0x7f60583785cb in folly::observer_detail::Core::~Core()::$_2::operator()(std::unordered_set<std::shared_ptr<folly::observer_detail::Core>, std::hash<std::shared_ptr<folly::observer_detail::Core> >, std::equal_to<std::shared_ptr<folly::observer_detail::Core> >, std::allocator<std::shared_ptr<folly::observer_detail::Core> > > const&) const folly/experimental/observer/detail/Core.cpp:156
>     #4 0x7f6058343cdc in auto folly::SynchronizedBase<folly::Synchronized<std::unordered_set<std::shared_ptr<folly::observer_detail::Core>, std::hash<std::shared_ptr<folly::observer_detail::Core> >, std::equal_to<std::shared_ptr<folly::observer_detail::Core> >, std::allocator<std::shared_ptr<folly::observer_detail::Core> > >, folly::SharedMutexImpl<false, void, std::atomic, false, false> >, (folly::detail::MutexLevel)1>::withWLock<folly::observer_detail::Core::~Core()::$_2>(folly::ob
server_detail::Core::~Core()::$_2&&) folly/Synchronized.h:210
>     #5 0x7f6058343a17 in folly::observer_detail::Core::~Core() folly/experimental/observer/detail/Core.cpp:154
>     #6 0x7f605838b8ca in std::_Sp_counted_ptr<folly::observer_detail::Core*, (__gnu_cxx::_Lock_policy)2>::_M_dispose() buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/bits/shared_ptr_base.h:378
>     #7 0x7f605834d411 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/bits/shared_ptr_base.h:156
>     #8 0x7f605834d332 in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count() buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/bits/shared_ptr_base.h:686
>     #9 0x7f605834d23a in std::__shared_ptr<folly::observer_detail::Core, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr() buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/bits/shared_ptr_base.h:1125
>     #10 0x7f605833c416 in std::shared_ptr<folly::observer_detail::Core>::~shared_ptr() buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/bits/shared_ptr.h:93
>     #11 0x7f6058376413 in folly::observer_detail::ObserverManager::scheduleRefresh(std::shared_ptr<folly::observer_detail::Core>, unsigned long)::'lambda'()::~() folly/experimental/observer/detail/ObserverManager.h:91
>     #12 0x7f6058377014 in unsigned long folly::detail::function::execSmall<folly::observer_detail::ObserverManager::scheduleRefresh(std::shared_ptr<folly::observer_detail::Core>, unsigned long)::'lambda'()>(folly::detail::function::Op, folly::detail::function::Data*, folly::detail::function::Data*) folly/Function.h:592
>     #13 0x7f6058377788 in folly::Function<void ()>::exec(folly::detail::function::Op, folly::detail::function::Data*, folly::detail::function::Data*) const folly/Function.h:649
>     #14 0x7f6058376380 in folly::Function<void ()>::~Function() folly/Function.h:781
>     #15 0x7f6058477b99 in folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()::operator()() const folly/experimental/observer/detail/ObserverManager.cpp:73
>     #16 0x7f6058473de8 in void std::__invoke_impl<void, folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()>(std::__invoke_other, folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()&&) buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/bits/invoke.h:60
>     #17 0x7f6058473c08 in std::__invoke_result<folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()>::type std::__invoke<folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()>(folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()&&) buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/bits/invok
e.h:95
>     #18 0x7f6058473b66 in decltype(std::__invoke(_S_declval<0ul>())) std::thread::_Invoker<std::tuple<folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()> >::_M_invoke<0ul>(std::_Index_tuple<0ul>) buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/thread:234
>     #19 0x7f6058473a43 in std::thread::_Invoker<std::tuple<folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()> >::operator()() buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/thread:243
>     #20 0x7f6058473549 in std::thread::_State_impl<std::thread::_Invoker<std::tuple<folly::observer_detail::ObserverManager::UpdatesManager::CurrentQueue::CurrentQueue()::'lambda'()> > >::_M_run() buck-out/cells/fbsource/gen/third-party/gcc/7.x/stdc++-headers#header-mode-symlink-tree-with-header-map,headers/thread:186
>     #21 0x7f60576bac5f in std::execute_native_thread_routine(void*) third-party/gcc/7.x/libstdc++-v3/src/c++11/thread.cc:83
>     #22 0x7f605639e6b5 in start_thread /home/engshare/third-party2/glibc/2.26/src/glibc-2.26/nptl/pthread_create.c:465:7
>     #23 0x7f6055ecdebe in __GI___clone /home/engshare/third-party2/glibc/2.26/src/glibc-2.26/sysdeps/unix/sysv/linux/x86_64/clone.S:95
>
> SUMMARY: UndefinedBehaviorSanitizer: unsigned-integer-overflow folly/experimental/observer/detail/Core.cpp:179:9
```

Fix the error by rearranging increment and decrement operations.

Reviewed By: leikahing

Differential Revision: D19164999

fbshipit-source-id: d3c9b638492d0bf44c2acaac1e95fafe8b785182