Summary:
[Folly] Cut build config items for `bits/functexcept.h`.

Folly no longer uses the non-portable functions declared in that internal libstdc++ header.

Reviewed By: mzlee

Differential Revision: D7119064

fbshipit-source-id: 6879dc6a5bc490726b188d65d7686a2eca136980

Summary:
Removing calls to folly::Promise::getFuture from Future-inl.h's simpler cases. Replacing with getSemiFuture.

In the case of the collect variants I continue to return a Future, completing inline, until those functions are modified to return SemiFuture.

Reviewed By: yfeldblum

Differential Revision: D7103938

fbshipit-source-id: 3737887a934cd0fe8f7c1511ae2ba252ea047a49

Summary:
Some OSes do not define `IP_MTU_DISCOVER` or `IPV6_MTU_DISCOVER`. As such, this would result in the function argument parameter `df` being unused, which is a warning that is then treated as an error.

Earlier today (2806dda4), this logic was added about setting the DF which broke Mac builds.
Closes https://github.com/facebook/folly/pull/791

Reviewed By: igorsugak

Differential Revision: D7116863

Pulled By: yfeldblum

fbshipit-source-id: 5092891c8977a44ab58723f8cef352dd4eaa1210

Summary:
Exposed by UBSAN:
{P59121025}
{P59121310}
{P59121558}

Add appropriate checks to avoid the UB.

Reviewed By: yfeldblum

Differential Revision: D7112776

fbshipit-source-id: 82bd9f85ed4c82aa1b030a38d6ad9358e8f2d38a

Summary: Some application requires IP not to fragment the the datagram. Add an API to AsyncUDPSocket to set such option.

Reviewed By: siyengar

Differential Revision: D5421406

fbshipit-source-id: 6cd3ab262f1420e22eb0948e0e2bfef77b7b6e92

Summary:
Introduce a specialization for `std::vector<bool>` as the existing
specialization for "other ranges" is not sufficient for binding the
proxy iterator (`bit_const_reference`) to an lvalue when iterating over
the `vector<bool>`.

I do not think you can simply change the type from `const auto&` to `auto&&` when iterating over the container for the "other ranges" specialization.  This is because we cannot bind an rvalue to an lvalue reference (which is the function argument type for our `construct` specializations).

See #752 and https://github.com/facebook/folly/pull/756 for more info.
Closes https://github.com/facebook/folly/pull/781

Reviewed By: andrewjcg

Differential Revision: D7078659

Pulled By: yfeldblum

fbshipit-source-id: 0089183a3c68d20ed14e483859e950dfb4ae729e

Summary:
Add a find_package module for Snappy
Closes https://github.com/facebook/folly/pull/783

Reviewed By: simpkins

Differential Revision: D7079554

Pulled By: yfeldblum

fbshipit-source-id: bf5dc3f3c37367f43fcbf8b40aaa3bb0a030bee5

Summary:
Previously, there are a number of tests in `FBVectorTestBenchmarks.cpp.h` that
are not used anywhere. This diff separates out the tests from the benchmarks
and actually include them in `FBVectorTest.cpp`.

Reviewed By: yfeldblum

Differential Revision: D7103453

fbshipit-source-id: 9427bb1ddcebefb2bbd2c91707fdd572890dc42e

Summary:
getOpenSSLNumericVersion was not static, while getOpenSSLLongVersion() was.
Rather than change it to static, these functions should simply be free
functions.

Reviewed By: yfeldblum

Differential Revision: D7094066

fbshipit-source-id: 808a9d169100c9d94d466d9348418a4e8a50c751

Summary: [Folly] Tweak throw_exception condition, fixing reference to `__GNUC__` and restructuring to make adding checks for alternative compilers more trivial.

Reviewed By: mzlee

Differential Revision: D7102307

fbshipit-source-id: e4e00ded71f37db8fa93822744b608b42960a58a

Reviewed By: yfeldblum

Differential Revision: D7091797

fbshipit-source-id: cbba7e5c17e1b6d4446570fb7a2b888db8bcd17e

Summary:
Re-committing.  Original: D6993857 revert: D7051998

Fixes for hazptr deletion on map destruction.
Several iteration cases don't properly release their hazard pointers.
This isn't disastrous, but means objects may stick around longer than necessary.
Adds tests and fixes for iteration to ensure we eagerly reset all hazard pointers.

Reviewed By: yfeldblum

Differential Revision: D7063727

fbshipit-source-id: 2ae32ead4965b37866096d2a8c6ea8c42c201335

Summary: [Folly] Let `to_signed` be `constexpr` under C++11 rules.

Reviewed By: simpkins

Differential Revision: D7079545

fbshipit-source-id: 69a56f2180f9ec3492cd1ad9cd26dd8bba255442

Summary:
CMake find_package modules are case sensitive. Since the script is called
"FindLZ4.cmake" the corresponding call to `find_package` must match LZ4
and not "lz4".

For an example of the problem, see the [Travis Log](https://travis-ci.org/facebook/folly/jobs/345661072). Namely:

```
CMake Warning at CMake/folly-deps.cmake:101 (find_package):
  No "Findlz4.cmake" found in CMAKE_MODULE_PATH.
Call Stack (most recent call first):
  CMakeLists.txt:65 (include)
CMake Warning (dev) at CMake/folly-deps.cmake:101 (find_package):
  Findlz4.cmake must either be part of this project itself, in this case
  adjust CMAKE_MODULE_PATH so that it points to the correct location inside
  its source tree.
```

This was not caught on my local machine as I use case-insensitive options in my terminal; in addition, this is not a "hard error" for CMake, so the builds happily continued successfully when 7dc5a4ed landed.
Closes https://github.com/facebook/folly/pull/782

Reviewed By: simpkins

Differential Revision: D7079535

Pulled By: yfeldblum

fbshipit-source-id: dd51d8c6ffa804be72c2d9cd264890280dcf5ab9

Summary: [Folly] Cut `folly/portability/BitsFunctexcept.h`.

Reviewed By: simpkins

Differential Revision: D7066504

fbshipit-source-id: ed260ab36759a58dee103addd92c6a5a47dac330

Summary: Add DECLARE/DEFINE_uint32 to the portability layer

Reviewed By: yfeldblum

Differential Revision: D7085534

fbshipit-source-id: 3f6f1bf79371b052706f4b3a03dca1d503b879da

Summary:
folly::dynamic's operator[] was documented as never invalidating
iterators.  In the object case when a key is implicitly inserted the
underlying unordered_map can rehash, which does invalidate the iterators.
This diff amends the comment to reflect this case.

Reviewed By: yfeldblum

Differential Revision: D7085861

fbshipit-source-id: 41ce0497bc60dba9f4529d10010f3b92f9a6c2b3

Summary:
Adds a find_package module for Zstd.
Closes https://github.com/facebook/folly/pull/785

Reviewed By: pixelb

Differential Revision: D7080036

Pulled By: yfeldblum

fbshipit-source-id: 018ff087df725de5344a245dea64ce1b813f6938

Summary: We are going to enable `-Werror=unused-parameter` flag and I need to manually fix some files so we rest of this process can be automated with a tool called clang-tidy.

Reviewed By: yfeldblum

Differential Revision: D7071617

fbshipit-source-id: 0165d9c79834b479ad0f598ea64404a86f47dcc6

Summary:
[Folly] `to_signed` and `to_unsigned`, for casting a value to the signed or unsigned version of the value's type.

And use them in time conversion functions.

Reviewed By: markw65

Differential Revision: D7020215

fbshipit-source-id: 47a6aeeea487cd7d59d23e7ded40cc66dcc57c52

Summary:
[Folly] `throw_exception` to support `-fno-exceptions`, switching all invocations of `std::__throw_....`.

Removes the need to use the non-portable `bits/functexcept.h`.

Reviewed By: mzlee, ot

Differential Revision: D7050335

fbshipit-source-id: 53d15639baa268a51f703816f04f314454d64979

Summary:
This test suite used to wrap equality of two paths by using `EXPECT_TRUE` to
avoid an old bug in GTest 1.6.0. Now that we use GTest 1.8.0, we can
simplify our test.
Closes https://github.com/facebook/folly/pull/780

Differential Revision: D7052503

Pulled By: yfeldblum

fbshipit-source-id: 5459736fca04cc45acf88a3d7dffc855ad7c9376

Summary: format changes, purely generated by clang-format.

Differential Revision: D7035579

fbshipit-source-id: 8452e1613adefe7dcfbbed4a3ef97be681790416

Summary: Packing the structs disregards the alignment of the storage. We should only do this on platforms where we do not need alignment.

Reviewed By: yfeldblum

Differential Revision: D7058593

fbshipit-source-id: 63b0d86bcf8b4f660ca244b1a4696e3ca64ecd6a

Reviewed By: yfeldblum

Differential Revision: D7060959

fbshipit-source-id: 914c517b4c8e93c15771f6acefaddce3138776a4

Summary:
Add a CMake find_package script for LZ4

simpkins
Closes https://github.com/facebook/folly/pull/778

Reviewed By: simpkins

Differential Revision: D7064988

Pulled By: yfeldblum

fbshipit-source-id: 60596ead4b4fd38474dab4c33d4c3fbb0f37549c

Summary:
Clang does not support the warning option "-Wclobbered", so we cannot
do a pragma push and pop for this warning. So, we push and pop this
particular warning for GCC only.

As it stands currently, Clang accepts `#pragma GCC` directives. If this
sort of thing comes up more in the future, it may make sense for Folly
to define a macro for easily disabling warnings for either just GCC or
just Clang.

simpkins yfeldblum
Closes https://github.com/facebook/folly/pull/779

Reviewed By: simpkins

Differential Revision: D7059916

Pulled By: yfeldblum

fbshipit-source-id: a6d420dc6ae435e3be1229b2bb421910bc8794ff

Summary:
Clear hazard pointers in ~hazptr_array() and ~hazptr_local().
Added tests to detect uncleared hazard pointers when using hazptr_array and hazptr_local.

Differential Revision: D6995057

fbshipit-source-id: 5b8fa1d197c3959ed670d0a019959bd57f5df3d0

Reviewed By: igorsugak

fbshipit-source-id: 4a93675cc1931089ddd574cacdb15d228b1e5f37

Summary: Since sysfs doesn't have cache information for the CPU on Android guard this on Android

Reviewed By: yfeldblum

Differential Revision: D7051199

fbshipit-source-id: 20fcfa91aa2f642c6cab33b0fb55f121b609d58f

Reviewed By: everiq, igorsugak

Differential Revision: D7046710

fbshipit-source-id: 8e10b1f1e2aecebbfb229c742e214db887e5a461

Summary:
This allows to create a Channel with AsyncSSLSocket while evb in not looping yet.
Also add ssl channel tests to thrift.

Reviewed By: yfeldblum

Differential Revision: D6991017

fbshipit-source-id: 0852b18e03a6b9d072cb4ec0182f1a41a5960eef

Summary:
[Folly] Fix `folly/experimental/hazptr/` under gcc7, which has a bug in emitting TLS init functions for `extern thread_local` variables.

Fixes:
```
folly/experimental/hazptr/test/HazptrTest.cpp:642: error: undefined reference to 'TLS init function for folly::hazptr::tls_priv_data_'
folly/experimental/hazptr/test/HazptrTest.cpp:642: error: undefined reference to 'TLS init function for folly::hazptr::tls_priv_data_'
```

The trick is to use a template class with `static thread_local` members with member definitions in the same header, and then to use only one instance of that template class.

Reviewed By: pixelb, magedm

Differential Revision: D7047235

fbshipit-source-id: 0551179a40f13796d6c0bb99aa806c73bd9dd471

Summary:
Original commit changeset: bee63b3f597d.

Original revision is breaking integration tests by failing with the SIGSEGV in operator++, please check D6993857 for more details.

Reviewed By: anshulverma

Differential Revision: D7051998

fbshipit-source-id: e5cfbb22aee5f5ec9871a9a34bb27eb5b0036d1b

Summary:
Fixes for hazptr deletion on map destruction.

Several iteration cases don't properly release their hazard pointers.
This isn't disastrous, but means objects may stick around longer than necessary.

This diff adds tests and fixes for iteration to ensure we eagerly reset all hazard pointers.

Reviewed By: magedm

Differential Revision: D6993857

fbshipit-source-id: bee63b3f597d1ed16cae5ed22a971fd4be2e1a77

Summary:
If a pthread_rwlock_t shared mutex is currently write-locked, we can
find its owner. However, if it is not write-locked or read-locked
(possibly by multiple threads), we will be unable to find the owner.

We can extend our deadlock detector to find deadlocks involving write-locked
pthread_rwlock_t mutexes as well.

Example output:

  Type "deadlock" to detect deadlocks.
  (gdb) deadlock
  Found deadlock!
  Thread 2 (LWP ...) is waiting on pthread_mutex_t (0x...) held by Thread 3 (LWP ...)
  Thread 3 (LWP ...) is waiting on pthread_rwlock_t (0x...) held by Thread 2 (LWP ...)

Reviewed By: yfeldblum

Differential Revision: D6974509

fbshipit-source-id: 8e64cb35f93958a9785070184df4c818b086ff0f

Summary:
The install step for folly CMake-based builds installs a folly-config.cmake
file that downstream projects can use to depend on folly in their own
CMakeLists.txt files.

CMakeLists.txt was previously generating the folly-config.cmake file by copying
CMake/folly-deps.cmake.  This seems wrong, as the installed folly-config.cmake
file should not contain `find_package()` statements that depend on CMake
modules only available in the folly source.

This adds a new folly-config.cmake.in template instead.

Reviewed By: yfeldblum

Differential Revision: D7035992

fbshipit-source-id: e6023094a807cf481ac49998c6f21b213be6c288

Summary:
When compiling with optimization enabled, gcc 7.2 complains about the
`childDir` variable potentially being clobbered by the child process after
`vfork()`.  This shouldn't matter since `childDir` is only used in the child
process, and not in the parent after the `vfork()`.

Reviewed By: yfeldblum

Differential Revision: D7035993

fbshipit-source-id: c80a4e18ad4f629a3d08e310cfd4500ebaf70994

Summary:
gcc does not complain about unknown `-Wno-*` flags by default, and older
versions of gcc do not support `-Werror=unknown-warning-option`.  Therefore
these checks for `-Wno-noexcept-type` and `-Wno-nullability-completeness` could
incorrectly indicate that the compiler supports these flags.

This changes the checks to check against the positive version of the warning
flag.

Reviewed By: yfeldblum

Differential Revision: D7035995

fbshipit-source-id: b1511d31721aeb779859848e20820c8a7fea4faa

Summary:
This brings us closer to being able to compile the open
source version of Folly with Clang. There are a few other
open pull requests that need to be addressed to allow us to
compile on Clang without any warnings that aren't already
explicitly disabled. See pull requests #745 and #756.

Closes https://github.com/facebook/folly/pull/772

Reviewed By: simpkins

Differential Revision: D7021595

Pulled By: yfeldblum

fbshipit-source-id: 350b972c74502ca2bc147f21428c622b19805b89