Summary: [Folly] Use simpler `cacheline_aligned` v.s. `CachelinePadded` in `LifoSem`, per comments atop `CachelinePadded`.

Reviewed By: aary

Differential Revision: D18166262

fbshipit-source-id: 807c668666fbbc9c16d5f449fa20234e56b29042

Summary: Fixes CVE-2019-11934

Reviewed By: mingtaoy

Differential Revision: D18020613

fbshipit-source-id: db82bb250e53f0d225f1280bd67bc74abd417836

Summary: `EliasFanoCoding` is used with 64-bits values in some logic, but we have no tests for that. Also, we weren't testing the larges admissible value. Finally, clarify in the comments what the various size types are for.

Reviewed By: philippv

Differential Revision: D18146549

fbshipit-source-id: e97ec9e1344db6e56a591a9b4c77c5929e10b22b

Reviewed By: Orvid

Differential Revision: D18169787

fbshipit-source-id: 1580df251c9ae87e9c268f1599d8c61232b48a4d

Summary: [Folly] Use attribute-based suppression in free-invoke traits v.s. pragma-based suppression for suppressing warnings about unused functions.

Reviewed By: vitaut

Differential Revision: D18112966

fbshipit-source-id: 2519f94d4ff4609c8418d4fd009a24acefe23ab2

Summary: [Folly] Remove `classname` from free-invoke traits inner names - it's already present for disambiguation in the outer private namespace name. Also adjust some of the names better to fit a singular pattern.

Reviewed By: vitaut

Differential Revision: D18112947

fbshipit-source-id: 0a3e76a72a16fff7d4c127c2994a8c38639083e2

Summary: [Folly] `is_constexpr_default_constructible`, for deciding whether a type is constexpr default-constructible.

Reviewed By: vitaut

Differential Revision: D18092652

fbshipit-source-id: a4642726a9495135abca1506c5dbb3d57c0e0558

Summary: [Folly] Cut `folly/futures/exercises/`, which was never finished.

Reviewed By: fugalh

Differential Revision: D18149557

fbshipit-source-id: ec5654c2d37996c42a3673523422bafe2a64c89e

Summary: The computation of the upper bits size is incorrect when both `kUpperFirst` and `kChecked` are true. In addition, when `kUpperFirst` is true, we might actually need 8 additional bytes in the buffer, for when `numLowerBits = 0`, so clarify the comment.

Reviewed By: philippv

Differential Revision: D18145144

fbshipit-source-id: 1372d39023e2d5d1c5ccbfb8e6c7af9a5a930f1d

Summary: In most cases lists are not iterated from the beginning, so reading the first word wastes a memory access.

Reviewed By: philippv

Differential Revision: D18140137

fbshipit-source-id: d5cd07a8b9ed67febcc89cef0314a538e5ca8423

Summary:
Our CI environment cannot directly connect to the internet,
and even if it could, doing so is undesirable to fetch javascript deps.
We maintain an offline mirror of packages used by the build(s) so that
we don't have to go out to the internet.

When running in fbsource, configure the environment to use that offline
mirror.

Reviewed By: chadaustin

Differential Revision: D18061773

fbshipit-source-id: 1a5e112f23c1baaedfb3dff0c4c2a1641f6bb9a1

Summary: Ask testpilot to include more output in test failures.

Reviewed By: fanzeyi

Differential Revision: D18061772

fbshipit-source-id: 0c14092557c21396c877d3b1776c5707437a117c

Reviewed By: davidtgoldblatt

Differential Revision: D16530636

fbshipit-source-id: 0ea2b9b628f3c41f87a3d31e0b4c1dc71101f639

Summary:
AsyncServerSocket::bind - call bindSocket with isExistingSocket = false

(Note: this ignores all push blocking failures!)

Reviewed By: danobi

Differential Revision: D18144178

fbshipit-source-id: 0c673bb397fabb737f8595dd0453826bb57c826e

Summary: [Folly] Change an `#ifdef` to a constexpr ternary for `MemoryMapping`.

Reviewed By: meyering

Differential Revision: D18024494

fbshipit-source-id: 7ee040891ecee9bccf46af1dc43e54946e676c70

Summary:
currently, the implementation of `eden prefetch` calls into
a mercurial function that is overly eager in making network connections,
which results in what should be a fast NOP second prefetch call taking
more time than is desirable.

This diff adds a little cache to avoid repeatedly calling prefetch
for the same directory more than once for the life of the getdeps
process.

Given the usage pattern of getdeps it is OK that we don't provide
a way to invalidate this cache.

Reviewed By: fanzeyi

Differential Revision: D18005408

fbshipit-source-id: 0ec3f477da1043a5a715704b512c81fcfaa0acde

Summary:
[Folly] Optimize `Function::operator()` codegen for size and speed.

* Avoid translating between values and references for trivially-copyable values.
* Avoid shifting all arguments to make room for the function object address.

In the optimal case, the codegen for calling a `Function` with many arguments translates into just a `jmp`.

See:
* https://github.com/thecppzoo/zoo/commits/master/inc/zoo/AnyCallable.h
* https://github.com/bloomberg/bde/blob/3.38.0.1/groups/bsl/bslstl/bslstl_function.h
* https://github.com/bloomberg/bde/blob/3.38.0.1/groups/bsl/bslmf/bslmf_forwardingtype.h

Given this example code:

```lang=c++,name=check.cpp
extern "C" void check_0(folly::Function<void()>& f) { f(); }
extern "C" void check_1(int i, folly::Function<void(int)>& f) { f(i); }
extern "C" void check_2(int i, int j, folly::Function<void(int, int)>& f) { f(i, j); }
extern "C" void check_3(int i, int j, int k, folly::Function<void(int, int, int)>& f) { f(i, j, k); }
extern "C" void check_4(int i, int j, int k, int l, folly::Function<void(int, int, int, int)>& f) { f(i, j, k, l); }
```

Before:

```name=check.o
0000000000000000 <check_0>:
   0:   ff 67 30                jmp    QWORD PTR [rdi+0x30]
0000000000000000 <check_1>:
   0:   55                      push   rbp
   1:   48 89 f0                mov    rax,rsi
   4:   48 89 e5                mov    rbp,rsp
   7:   48 83 ec 10             sub    rsp,0x10
   b:   89 7d fc                mov    DWORD PTR [rbp-0x4],edi
   e:   48 8d 75 fc             lea    rsi,[rbp-0x4]
  12:   48 89 c7                mov    rdi,rax
  15:   ff 50 30                call   QWORD PTR [rax+0x30]
  18:   c9                      leave
  19:   c3                      ret
0000000000000000 <check_2>:
   0:   55                      push   rbp
   1:   48 89 d0                mov    rax,rdx
   4:   48 89 e5                mov    rbp,rsp
   7:   48 83 ec 10             sub    rsp,0x10
   b:   89 7d f8                mov    DWORD PTR [rbp-0x8],edi
   e:   89 75 fc                mov    DWORD PTR [rbp-0x4],esi
  11:   48 8d 55 fc             lea    rdx,[rbp-0x4]
  15:   48 8d 75 f8             lea    rsi,[rbp-0x8]
  19:   48 89 c7                mov    rdi,rax
  1c:   ff 50 30                call   QWORD PTR [rax+0x30]
  1f:   c9                      leave
  20:   c3                      ret
0000000000000000 <check_3>:
   0:   55                      push   rbp
   1:   48 89 c8                mov    rax,rcx
   4:   48 89 e5                mov    rbp,rsp
   7:   48 83 ec 10             sub    rsp,0x10
   b:   89 7d f4                mov    DWORD PTR [rbp-0xc],edi
   e:   89 75 f8                mov    DWORD PTR [rbp-0x8],esi
  11:   89 55 fc                mov    DWORD PTR [rbp-0x4],edx
  14:   48 8d 4d fc             lea    rcx,[rbp-0x4]
  18:   48 8d 55 f8             lea    rdx,[rbp-0x8]
  1c:   48 8d 75 f4             lea    rsi,[rbp-0xc]
  20:   48 89 c7                mov    rdi,rax
  23:   ff 50 30                call   QWORD PTR [rax+0x30]
  26:   c9                      leave
  27:   c3                      ret
0000000000000000 <check_4>:
   0:   55                      push   rbp
   1:   4c 89 c0                mov    rax,r8
   4:   48 89 e5                mov    rbp,rsp
   7:   48 83 ec 10             sub    rsp,0x10
   b:   89 7d f0                mov    DWORD PTR [rbp-0x10],edi
   e:   89 75 f4                mov    DWORD PTR [rbp-0xc],esi
  11:   89 55 f8                mov    DWORD PTR [rbp-0x8],edx
  14:   89 4d fc                mov    DWORD PTR [rbp-0x4],ecx
  17:   4c 8d 45 fc             lea    r8,[rbp-0x4]
  1b:   48 8d 4d f8             lea    rcx,[rbp-0x8]
  1f:   48 8d 55 f4             lea    rdx,[rbp-0xc]
  23:   48 8d 75 f0             lea    rsi,[rbp-0x10]
  27:   48 89 c7                mov    rdi,rax
  2a:   ff 50 30                call   QWORD PTR [rax+0x30]
  2d:   c9                      leave
  2e:   c3                      ret
```

After:

```name=check.o
0000000000000000 <check_0>:
   0:   ff 67 30                jmp    QWORD PTR [rdi+0x30]
0000000000000000 <check_1>:
   0:   ff 66 30                jmp    QWORD PTR [rsi+0x30]
0000000000000000 <check_2>:
   0:   ff 62 30                jmp    QWORD PTR [rdx+0x30]
0000000000000000 <check_3>:
   0:   ff 61 30                jmp    QWORD PTR [rcx+0x30]
0000000000000000 <check_4>:
   0:   41 ff 60 30             jmp    QWORD PTR [r8+0x30]
```

Reviewed By: luciang

Differential Revision: D17523239

fbshipit-source-id: beed0bae827aad8290e807374e8596f71f98ce99

Summary: This allows the caller to guarantee that the coroutine starts executing on the current thread. This can be necessary for correctness in some situations, where having the coroutine enqueued to the executor, as `.start()` does, and potentially allowing other code to run in the meantime could invalidate some assumptions.

Reviewed By: andriigrynenko

Differential Revision: D18076197

fbshipit-source-id: a6c5c226f2d7189f37e8f9713a30896767e9b8e9

Summary:
MemorySanitizer was failing due to uninitialized memory in the stack.

```
==596112==WARNING: MemorySanitizer: use-of-uninitialized-value
[testserver][INFO]: IOBuff received. Len = 128
    #0 0x9d4b21 in folly::SocketAddress::updateUnixAddressLength(unsigned int) xplat/folly/SocketAddress.cpp:710:7
    #1 0x9d4740 in folly::SocketAddress::setFromSockaddr(sockaddr_un const*, unsigned int) xplat/folly/SocketAddress.cpp:338:3

  Uninitialized value was created by an allocation of 'addrStorage' in the stack frame of function '_ZN5folly17AsyncServerSocket12handler
ReadyEtNS_13NetworkSocketEt'
    #0 0x7de840 in folly::AsyncServerSocket::handlerReady(unsigned short, folly::NetworkSocket, unsigned short) xplat/folly/io/async/Asyn
cServerSocket.cpp:835
```

Differential Revision: D18086738

fbshipit-source-id: f36013b157d7b34d3b29c08d4533f01be1a1a8c9

Summary:
Until [very recently](https://github.com/google/googletest/pull/2517), `googletest` did not print the skip message in any shape or form, so nothing can possibly depend on us customizing the skip message here.

The default is perfectly fine, let's keep it simple.

Reviewed By: yfeldblum

Differential Revision: D18051635

fbshipit-source-id: f7b889b0adf5e34a70c2579a34748bb159809b3c

Summary:
Add `annotate_ignore_thread_sanitizer_guard` class.

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D18045913

fbshipit-source-id: 39113e8df3deef3374a3c44246bc55a156bc4d8d

Summary: Allow AsyncServerSocket::bind to be called for multiple addrs (same as for port bind)

Reviewed By: yfeldblum

Differential Revision: D18046496

fbshipit-source-id: efde498fbaa02357d7c66905b8c1e5e839062076

Reviewed By: yfeldblum, lewissbaker

Differential Revision: D18052431

fbshipit-source-id: 9fb1b3faba25093cf67bdf9c6cbe5cc70794deee

Summary:
Generalises the specialisation of collectAllRange() and collectAllWindowed() on a std::vector<Task<T>> to now work for any std::vector<SemiAwaitable>.

This will allow them to work when passed a std::vector<TaskWithExecutor<T>>.

Reviewed By: andriigrynenko

Differential Revision: D18049190

fbshipit-source-id: 658213f93ff3eadda041ac2262cc6bcb759e331c

Summary:
[Folly] Extract `strlcpy` to a new c-string lib in `folly/lang/CString.h`.

This new lib would be for routines that should but don't appear in `<cstring>`.

Reviewed By: marcinpe

Differential Revision: D18032925

fbshipit-source-id: 746851f68e86a5ec2bea5cc659c19c4fe2f0f02a

Summary: [Folly] Guard the forward declaration of `fibers::Baton` by the same condition which determines whether `fibers::Baton` is ever used in futures.

Reviewed By: lewissbaker

Differential Revision: D17962552

fbshipit-source-id: 2494026999cd170c36adec91108732254212abf1

Summary: [Folly] Prefer a C++ symbol over back-defining `MAP_POPULATE`.

Reviewed By: nbronson

Differential Revision: D18024313

fbshipit-source-id: 7f3b754a7911d6947e5a6f34860f9f0d3833aa51

Summary: [Folly] Add missing `inline` to `co_current_executor`.

Reviewed By: ericniebler

Differential Revision: D18034078

fbshipit-source-id: 8c212ef6278112cc8e90075494a3038d9111bb64

Summary:
The PAUSE instruction's latency varies widely across x64
architectures, resulting in too much spinning on Skylake in some
scenarios.  This diff switches to using cycle counts to limit spinning
on x64, so that the minimum and maximum spin durations are independent
of asm_volatile_pause's latency.

Reviewed By: yfeldblum

Differential Revision: D17961663

fbshipit-source-id: 6170bfa48d007ca21b73b1a5c7e68da0043cda2c

Summary:
This avoids invalidating the entire build in response
to just running `hg amend`, which is frustrating and slow.

Reviewed By: chadaustin

Differential Revision: D18005409

fbshipit-source-id: ef93313859919298be78204046eb08bcadc5398e

Summary: [Folly] Backport invocability variable templates: `is_invocable_v`, `is_invocable_r_v`, `is_nothrow_invocable_v`, `is_nothrow_invocable_r_v`. And for the member-invoke and free-invoke traits.

Reviewed By: ericniebler

Differential Revision: D17950331

fbshipit-source-id: 5409d7a72116b0976573e1f64760c5ef9274966f

Summary:
If CH parsing is enabled, also parse out the ServerName extension. OpenSSL 1.1.1
changes the behavior of `SSL_get_servername`: an SNI value is stored in
the underlying SESSION if and only if both parties negotiated that SNI.

There are some situations where one would wish to retrieve the original
ServerName that the client sent.

Reviewed By: knekritz

Differential Revision: D17893443

fbshipit-source-id: b29ee42e90629c869dd5e68c93c7cb2abc19745f

Summary:
No longer allow a child task's modifications to the RequestContext made before it's first suspension point to bleed into the next child task's context.

Now always restore the parent task's RequestContext before starting subsequent tasks.

Reviewed By: andriigrynenko

Differential Revision: D17846070

fbshipit-source-id: 44e206d4c833759fc36c7d1bd0f3545ca6bb9ab1

Summary: Relax DFATAL message

Reviewed By: yfeldblum

Differential Revision: D18001089

fbshipit-source-id: 2027d0257e1cba6905dc4eb1863b70a8fe6a7366

Summary: trim, ltrim and rtrim are similar to ltrimWhitespace, rtrimWhitespace and trimWhitespace but you can specify what you want to remove

Reviewed By: yfeldblum

Differential Revision: D17946658

fbshipit-source-id: 9bdc5e6eb810e628a8c16b5142c17a3313f884f2

Summary:
ThreadPoolExecutor::getPoolStats depends on derived classes implementation.
Calling `getPoolStats` is specially useful from `ThreadPoolExecutor::withAll`.

This change moves registration of thread pool executor instances to derived classes
to avoid `ThreadPoolExecutor::withAll` racing with thread pool destruction while calling `getPoolStats`.

Reviewed By: yfeldblum

Differential Revision: D17965135

fbshipit-source-id: 637de55ed78b085dc86fffa0e0f4a66cd4cfcede

Summary: keepAliveRelease code reorg

Reviewed By: kevin-vigor

Differential Revision: D17835172

fbshipit-source-id: 48c60b04324f0d9bd1ac628e2625d3d4d2654c99

Summary: Add missing switch case

Reviewed By: yfeldblum

Differential Revision: D17945170

fbshipit-source-id: 8128c40e1c86b2a5ff8d1bad3c0e9fe197adc174

Summary:
this should help avoid this particular error:

```
IOError: [Errno socket error] [Errno 11001] getaddrinfo failed
```

Reviewed By: chadaustin

Differential Revision: D17886598

fbshipit-source-id: bd9f5b84ebd7ca5c339be3afec3a975fa907d052

Summary:
This diff allows passing a watchman version number override
via the environment as well as via the cmake `WATCHMAN_VERSION_OVERRIDE`
option.

To help invalidate the build I've added a new section to the manifest
files that allows listing out additional env vars that the project
hashes should be sensitive to.  The effect of this is that we'll
re-run the cmake configure step if the listed env vars are changed.

Reviewed By: Ben0mega

Differential Revision: D17865896

fbshipit-source-id: 8ea5572b0b9b7af95ec5c310e494cb17a139ced4