Summary:
We are using `bm_max_iters` in folly and other part of the code in fbcode but it didn't really exist in Benchmark.cpp. For example: https://github.com/facebook/folly/blob/master/folly/test/function_benchmark/main.cpp#L29

This patch adds back this functionality.

This diff depends on D3990600.

Reviewed By: yfeldblum

Differential Revision: D3989499

fbshipit-source-id: d2303b2bebb196e84a592d54a72af68171971491

Summary: This patch prepares the later diff which will add a new flag. Just make things nice.

Reviewed By: igorsugak

Differential Revision: D3990600

fbshipit-source-id: d4f53a5b44708ca025e4f6615d161b24de685931

Summary:
Remove all code that create large strings.

This diff does not remove code that deals with large strings, so that the transition to libgcc will be smoother. Note that the FBSTRING_ASSERT inside of setCapacity will be disabled in the libgcc build.

Reviewed By: luciang, ot

Differential Revision: D3977459

fbshipit-source-id: 09c1712854b31509138c5cc8baf19caf3c715bb6

folly: symbolizer: increase default signal-handler symbolizer elf file cache size (make it work with large number of .so)

Summary:
Bump the default size so we can symbolize symbols in dynamically linked
binaries with lots and lots of shared libraries :)

folly/experimental/symbolizer/ElfCache.h
```
  * Will not grow; once the capacity is reached, lookups for files that
  * aren't already in the cache will fail (return nullptr).
  class SignalSafeElfCache
```

Reviewed By: ot, philippv

Differential Revision: D3984649

fbshipit-source-id: acdca9b9adf6c16f3a1556bc3f57b28844cdd9cc

Summary: We want to fail fast if we attempt to stop a scheduler that was not running

Reviewed By: yfeldblum

Differential Revision: D3976919

fbshipit-source-id: d8aa8b35aa9e22758e6a7ef64f48a7dd6d990b1c

Summary:
When `delayed` is called on the Future, the underlying `futures::sleep` call runs on a timer thread, and the resulting callback is called on the same thread. Therefore, in the following sequence:

  f.via(&someExecutor).within(one_ms).then([&]() { /* [1] */ })

The code in [1] is not running in someExecutor. This can cause confusion by users of the library who expect the initial `via` to be sticky.

This change returns to the prior `Executor` after `delayed` is finished.

Reviewed By: yfeldblum

Differential Revision: D3979179

fbshipit-source-id: e1448f5603f0c9440490ae3bf0e670687f4179f3

Summary: Fix shadowing warnings.

Reviewed By: russoue

Differential Revision: D3979165

fbshipit-source-id: 19a3940e210e4d5a698dbc0e6d74b317a74a94fa

Summary:
When `delayed` is called on the Future, the underlying `futures::sleep` call runs on a timer thread, and the resulting callback is called on the same thread. Therefore, in the following sequence:

  f.via(&someExecutor).within(one_ms).then([&]() { /* [1] */ })

The code in [1] is not running in someExecutor. This can cause confusion by users of the library who expect the initial `via` to be sticky.

This change returns to the prior `Executor` after `delayed` is finished.

Reviewed By: yfeldblum

Differential Revision: D3979179

fbshipit-source-id: 936ff5626e8ac377ffb15babf573349466984e3a

Summary: The attribute `__returns_nonnull__` is only applicable for gcc 4.9 or later (https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/Function-Attributes.html#Function-Attributes)

Reviewed By: ot

Differential Revision: D3976598

fbshipit-source-id: 3c678a11c5046e5a8b7686327dbb3ebc9b598616

Summary: It's bad mkey. Says so on the tin can. Alert/annoy its users.

Reviewed By: yfeldblum, ot

Differential Revision: D3973625

fbshipit-source-id: 23f4e16182749d016084fcb378a1170ff402c259

Summary: no uses remain in folly

Reviewed By: yfeldblum

Differential Revision: D3972507

fbshipit-source-id: 356ddbcf24c217b0f589989ab6cc3910d0f7baf3

Updated example and methodology for using DeterministicSchedule support for auxiliary data and global invariants

Summary:
Depends on D3792669

Updating the test and methodology based on the experience with fine-grained testing dynamic MPMCQueue using DeterministicSchedule's support for auxiliary data and global invariants.

Updates D3675447

Reviewed By: djwatson

Differential Revision: D3794217

fbshipit-source-id: d2862895cb8dea120e758beeb24d6ae15191b013

Summary: Initialize Optional internal memory, so that "un-initialized memory" tools don't flag its callsites.

Reviewed By: yfeldblum

Differential Revision: D3960462

fbshipit-source-id: 3bd0109959fb93e040fa2e874f586b3508e46dd2

Summary:
folly::StringPieceHash has a large comment explaining why not to use it, but it's not marked as deprecated.

It's also conveniently named StringPieceHash and not StringPieceHashDEPRECATED so new uses appear from time to time.

Let's nuke the default before it does more damage.

Reviewed By: yfeldblum

Differential Revision: D3967239

fbshipit-source-id: 04b0564fdf2a70f1195ef2afdff092bc63cde975

Summary: #accept2ship

Reviewed By: bixue2010

Differential Revision: D3971138

fbshipit-source-id: 25e0aeddebf001dd8e27a4939842915ccf1000ad

Summary:
The following thrift file doesn't work:
  typedef set<i32> (cpp.template = "folly::sorted_vector_set") IntSet
  struct Test {
    1: map<i32, IntSet> m = {7: [1, 2]},
  }

The generated file looks like this:
  Test()
      : m(std::initializer_list<
          std::pair<const int32_t, folly::sorted_vector_set<int32_t>>>{
          {7, std::initializer_list<int32_t>{1, 2}}}) {}

Given that `std::set` allows implicit construction from `std::initializer_list`, it's probably okay to make `folly::sorted_vector_set` the same.

Reviewed By: ot

Differential Revision: D3968054

fbshipit-source-id: 978d59a7e545e44d603eeb9671815ac7f2c57342

Summary:
Enabling the proposed-for-upstream gcc -Wshadow-local option exposes this shadowing:
```
folly/io/async/AsyncSocket.cpp: In member function 'virtual void folly::AsyncSocket::connect(folly::AsyncSocket::ConnectCallback*, const folly::SocketAddress&, int, const OptionMap&, const folly::SocketAddress&)':
folly/io/async/AsyncSocket.cpp:421:11: error: declaration of 'rv' shadows a previous local [-Werror=shadow-compatible-local]
folly/io/async/AsyncSocket.cpp:364:9: error: shadowed declaration is here [-Werror=shadow-compatible-local]
```

Reviewed By: ngoyal, knekritz

Differential Revision: D3963873

fbshipit-source-id: 85b3ab1fc3b200b81615a00d66a183cc9c792a90

Summary:
This matches what the STL does with e.g. std::vector::swap() and std::shared_ptr::swap().

http://en.cppreference.com/w/cpp/container/vector/swap
http://en.cppreference.com/w/cpp/memory/shared_ptr/swap

Should be relatively uncontroversial, I would think.
Closes https://github.com/facebook/folly/pull/489

Reviewed By: magedm

Differential Revision: D3963285

Pulled By: yfeldblum

fbshipit-source-id: 3fa6bf77e66fa9a673cb648b0bf87b1db3caa6c8

Summary:
gcc's -Wshadow (and the under-review -Wshadow-local) would evoke this:
```
folly/io/Compression.cpp:650:9: error: declaration of 'rc' shadows a previous local [-Werror=shadow-compatible-local]
folly/io/Compression.cpp:637:7: error: shadowed declaration is here [-Werror=shadow-compatible-local]
folly/io/Compression.cpp:566:9: error: declaration of 'rc' shadows a previous local [-Werror=shadow-compatible-local]
folly/io/Compression.cpp:548:7: error: shadowed declaration is here [-Werror=shadow-compatible-local]
```
In each case, I removed the "int" from the latter declaration.

Reviewed By: philippv

Differential Revision: D3966308

fbshipit-source-id: 584cb9ffe8ba0e56914223c440efabe9e0de6b17

Summary: Outline all the non-trivial constructor and the destructor, `assign()`, and `append()` to reduce code size. The fast path of copy, and moves, are instead still inlined.

Reviewed By: philippv

Differential Revision: D3896612

fbshipit-source-id: 25050d4ba28d25da226a7bc49d5b542947d0c512

Reviewed By: lbrandy

Differential Revision: D3964328

fbshipit-source-id: 0b1dc2d4b2a1565019770668445a624625b8257e

Summary:
This diff adds BatchDispatcher, which can be used to batch values while performing IO.
This would be useful in writing single id code in node, and would be use to batch ids while doing IO at storage adapter.

Differential Revision: D3900404

fbshipit-source-id: f53aa352344ff55674c7544302b6a1b4726214b6

Summary:
Almost every method of `fbstring` needs to perform category
dispatching. The category constants are `size_t`, which become 8-byte
immediate values in the dispatching code, so even a simple `if
(category() == Category::isSmall)` is quite large. When inlined
hundreds of thousands of time, it adds up.

This diff redefines the category type to be 1 byte (without changing
the ABI). It also optimizes `size()` and `c_str()` and makes them
branch-free, which probably is not going to have any perf impact but
it saves a few bytes.

Generated code for some small functions:

- `reset()`
Before:
```
48 ba 00 00 00 00 00    movabs $0x1700000000000000,%rdx
00 00 17
48 89 f8                mov    %rdi,%rax
c6 07 00                movb   $0x0,(%rdi)
48 89 57 10             mov    %rdx,0x10(%rdi)
```

20 bytes

After:
```
48 89 f8                mov    %rdi,%rax
c6 47 17 17             movb   $0x17,0x17(%rdi)
c6 07 00                movb   $0x0,(%rdi)
```

10 bytes

- `c_str()`
Before:
```
48 b8 00 00 00 00 00    movabs $0xc000000000000000,%rax
00 00 c0
48 85 47 10             test   %rax,0x10(%rdi)
74 08                   je     401fd8
48 8b 07                mov    (%rdi),%rax
c3                      retq
0f 1f 40 00             nopl   0x0(%rax)
48 89 f8                mov    %rdi,%rax
```

26 bytes (without the `retq`)

After:
```
f6 47 17 c0             testb  $0xc0,0x17(%rdi)
48 89 f8                mov    %rdi,%rax
48 0f 45 07             cmovne (%rdi),%rax
```

11 bytes

- `size()`
Before:
```
48 b8 00 00 00 00 00    movabs $0xc000000000000000,%rax
00 00 c0
48 85 47 10             test   %rax,0x10(%rdi)
74 08                   je     401fa8
48 8b 47 08             mov    0x8(%rdi),%rax
c3                      retq
0f 1f 00                nopl   (%rax)
48 0f be 57 17          movsbq 0x17(%rdi),%rdx
b8 17 00 00 00          mov    $0x17,%eax
48 29 d0                sub    %rdx,%rax
```

36 bytes (without the `retq`)

After:
```
0f b6 57 17             movzbl 0x17(%rdi),%edx
b8 17 00 00 00          mov    $0x17,%eax
48 29 d0                sub    %rdx,%rax
48 0f 48 47 08          cmovs  0x8(%rdi),%rax
```

17 bytes

Reviewed By: philippv

Differential Revision: D3957276

fbshipit-source-id: ef40d82bbbb0456b1044421cd02133c268abe39b

Summary:
D3278901 never worked, GCC (at least 4.9) failed to propagate
`FOLLY_TARGET_ATTRIBUTE("arch=haswell")` down, `blsr` and `select64`
weren't inlined in EF coding on Haswell, showing up in CPU profile.

This diff switches back to inline assembly, removing second dispatching
mechanism (IFUNC; in additional to caller-side `Default` / `Nehalem` / `Haswell`
dispatching) for `compression::instructions`, and disables functionality on
compilers not supporting AT&T syntax (MSVC++) for now.

Added `FOLLY_ALWAYS_INLINE` to make sure failure to inline results in
compilation failure.

Reviewed By: ot

Differential Revision: D3959438

fbshipit-source-id: e40573fbfbf38991caa2cd70293aeaeeec3afad7

Summary:
Any attempt to copy or move an object returned by folly::partial
yields a compiler error because it is invoking the constructor
for wrapping callable objects, which triggers a type mismatch.

This diff fixes that by explicitly naming the default implementations
of copy and move constructors.

This diff also adds additional tests that fail to compile without this fix.

And then this diff also moves the Partial class into folly::detail,
because it is not meant to be named in user code, but only returned
by the folly::partial function.

Reviewed By: mhx

Differential Revision: D3923809

fbshipit-source-id: a8883951afd2a1999acbfffc51296393b058f860

Summary:
A ton of these functions are tiny and should be inlined. `throw std::out_of_range("bla")` generates quite a lot of code.

See godbolt from {D3940968}: https://godbolt.org/g/9K36Km

  advanceNoInline(S):
          movq    %rdi, %rax
          sarq    $32, %rax
          cmpl    %eax, %edi
          jg      .L20
          leal    1(%rdi), %eax
          ret
  .L20:
          subq    $8, %rsp
          call    S::outOfRange() [clone .isra.0]

vs previous implementation

  advance(S):
          movq    %rdi, %rdx
          sarq    $32, %rdx
          cmpl    %edx, %edi
          jg      .L14
          leal    1(%rdi), %eax
          ret
  .L14:
          pushq   %rbp
          pushq   %rbx
          movl    $16, %edi
          subq    $8, %rsp
          call    __cxa_allocate_exception
          movl    $.LC0, %esi
          movq    %rax, %rdi
          movq    %rax, %rbx
          call    std::out_of_range::out_of_range(char const*)
          movl    std::out_of_range::~out_of_range(), %edx
          movl    typeinfo for std::out_of_range, %esi
          movq    %rbx, %rdi
          call    __cxa_throw
          movq    %rax, %rbp
          movq    %rbx, %rdi
          call    __cxa_free_exception
          movq    %rbp, %rdi
          call    _Unwind_Resume

This pattern is in the standard library as well:
```
      reference
      at(size_type __n)
      {
	if (__n >= _Nm)
	  std::__throw_out_of_range(__N("array::at"));
	return _M_instance[__n];
      }
```

https://github.com/gcc-mirror/gcc/blob/edd716b6b1caa1a5cb320a8cd7f626f30198e098/libstdc%2B%2B-v3/include/tr1/array#L138

Reviewed By: yfeldblum

Differential Revision: D3947075

fbshipit-source-id: 6e174c725791762a533a534c8482ea9576460b86

Summary:
libdwarf headers moved from `/usr/include` to `/usr/include/libdwarf` in [dwarfutils 20160613-2](http://metadata.ftp-master.debian.org/changelogs/main/d/dwarfutils/unstable_changelog).

Adds a check for the library as well, and fixes a tiny typo in the `libunwind` check.

No longer checks for `libdwarf.h`; only `dwarf.h` is used.
Closes https://github.com/facebook/folly/pull/480

Reviewed By: yfeldblum

Differential Revision: D3878961

Pulled By: Orvid

fbshipit-source-id: 7970d33511bf6d351cec2c8077cb07b85f2f8d33

Summary:
No need to define our own.

Generated code is similar: https://godbolt.org/g/5xWrNx (one extra move instruction).

```
.L20:
        subq    $8, %rsp
        call    S::outOfRange() [clone .isra.0]
```

```
.LC1:
        .string "out of range"
.L26:
        subq    $8, %rsp
        movl    $.LC1, %edi
        call    std::__throw_out_of_range(char const*)
```

Reviewed By: Orvid

Differential Revision: D3945578

fbshipit-source-id: c65e9dea55e8f01f51766b2695af68d2bc92c266

Summary:
Acquire a SharedMutex at ThreadExit to ensure that after unlinking the ThreadEntry from
the list, future accessAllThreads() won't miss a destroying thread.

This is quite a dangerous fix as it changes some lock ordering semantics. ThreadLocal
elements are now destroyed while holding a lock, so if the destruction function
acquires a different lock, ordering must be consistent with other
uses of accessAllThreads().

I've made accessAllThreads() an opt-in feature via a template parameter and changed
all existing uses. I've also fixed a few lock ordering issues that arose due to this
change.

Reviewed By: andriigrynenko

Differential Revision: D3931072

fbshipit-source-id: 4d464408713184080079698df453b95873bb1a6c

Summary:
When using connectx to do TFO, apple has a bug
where the second write after a TFO write will cause
the socket to throw an ENOTCONN error instead of an
EAGAIN. Linux handles this case fine and returns an
EAGAIN, however apple returns ENOTCONN.

We solve this by treating ENOTCONN as an EAGAIN temporarily.

Reviewed By: yfeldblum

Differential Revision: D3942681

fbshipit-source-id: ab4f0b5fd6cdcfe9c584ea00849705a2d739d65f

Summary:
Adds TFO functions for apple devices
Also allows android as well by removing that
restriction. Newer versions of android support
TFO, so this allows us to experiment with them

Reviewed By: yfeldblum

Differential Revision: D3942664

fbshipit-source-id: faf439783b018cf7c987a2e3ade5ea6c0c02bf48

Summary:
Here's some godbolt: https://godbolt.org/g/9K36Km

  advanceNoInline(S):
          movq    %rdi, %rax
          sarq    $32, %rax
          cmpl    %eax, %edi
          jg      .L20
          leal    1(%rdi), %eax
          ret
  .L20:
          subq    $8, %rsp
          call    S::outOfRange() [clone .isra.0]

vs previous implementation

  advance(S):
          movq    %rdi, %rdx
          sarq    $32, %rdx
          cmpl    %edx, %edi
          jg      .L14
          leal    1(%rdi), %eax
          ret
  .L14:
          pushq   %rbp
          pushq   %rbx
          movl    $16, %edi
          subq    $8, %rsp
          call    __cxa_allocate_exception
          movl    $.LC0, %esi
          movq    %rax, %rdi
          movq    %rax, %rbx
          call    std::out_of_range::out_of_range(char const*)
          movl    std::out_of_range::~out_of_range(), %edx
          movl    typeinfo for std::out_of_range, %esi
          movq    %rbx, %rdi
          call    __cxa_throw
          movq    %rax, %rbp
          movq    %rbx, %rdi
          call    __cxa_free_exception
          movq    %rbp, %rdi
          call    _Unwind_Resume

Reviewed By: ot

Differential Revision: D3940968

fbshipit-source-id: b47a41e7cdd863fcef099ff3c21860b2979ee6e8

Summary:
`Range` has a somewhat inconsistent API: most methods assume
argument validity as a precondition (mirroring their STL
counterparts), others check the arguments and throw for invalid ones.

Since `Range` is intended as a zero-cost abstraction on top of
pointers/iterators, unchecked methods should be preferred. At this
point however we cannot change the semantics of `advance()` and other
methods. This diff adds new unchecked versions of these methods.

Reviewed By: luciang

Differential Revision: D3938480

fbshipit-source-id: 6952683ee0716aa1584e79584158fbf3e083b52e

Summary:
The original code `AC_DEFINE([FOLLY_SUPPLY_MISSING_INT128_TRAITS...` resulted in defining the constant FOLLY_FOLLY_SUPPLY_MISSING_INT128_TRAITS in folly-config.h. This patch fix the name of the constant so that the name match with what appear in Traits.h.
Closes https://github.com/facebook/folly/pull/485

Reviewed By: yfeldblum

Differential Revision: D3931349

Pulled By: Orvid

fbshipit-source-id: bd7e7d3580d02134d36706bd5836822135232d26

Summary: Fix includes in memory_resource.h

Reviewed By: yfeldblum

Differential Revision: D3935848

fbshipit-source-id: 713ce85ad17072779dfa1c667459e367c5e1d4b7

Summary:
`SharedMutexImpl::lockSharedImpl` has a potentially uninitialized access:

  Assume state = 0
  canAlreadyDefer = (state & kMayDefer) != 0 ==> false
  aboveDeferThreshold = (state & kHasS) >= (kNumSharedToStartDeferring - 1) * kIncrHasS ==> false

  if (canAlreadyDefer || (aboveDeferThreshold && !drainInProgress)) ==> false

  line:1452: gotSlot(slot)->compare_exchange_strong(...) uses slot uninitialized

Reviewed By: Orvid

Differential Revision: D3933638

fbshipit-source-id: 0fbce5c00b8b1f34e50c302cb88def97853c5afe

Summary:
This commit introduces a simple function reference type, similar to
std::reference_wrapper, but the template parameter is the function
signature type rather than the type of the referenced object.

A folly::FunctionRef is cheap to construct as it contains only a
pointer to the referenced callable and a pointer to a function which
invokes the callable.

The user of FunctionRef must be aware of the reference semantics:
storing a copy of a FunctionRef is potentially dangerous and should
be avoided unless the referenced object definitely outlives the
FunctionRef object. Thus any function that accepts a FunctionRef
parameter should only use it to invoke the referenced function and
not store a copy of it. Knowing that FunctionRef itself has reference
semantics, it is generally okay to use it to reference lambdas that
capture by reference.

Reviewed By: ericniebler

Differential Revision: D3277364

fbshipit-source-id: 0a7676919cd240da5b6e1f94cadba4289e0aca28

Summary:
This is a start to wrapping various SSL objects going forward so different
binaries can choose different version of OpenSSL (i.e., BoringSSL, OpenSSL
1.1.0, OpenSSL 1.0.2, etc.). There's no change to the caller - everyone just
uses 'SSLSession', but the implementation details vary

Reviewed By: siyengar

Differential Revision: D3707791

fbshipit-source-id: f895334a768cb7d43b41af40c9bc06be5307cc7f

Summary:
OpenSSL SSL_METHOD->get_cipher_by_char is not present in either OpenSSL
1.1.0 or BoringSSL. In addition, knekritz reports that time's being spent in
binary searching for cipher names.

Since the ciphercodes and names are (fairly) static, we store these in a static
hash map.

Reviewed By: siyengar

Differential Revision: D3275185

fbshipit-source-id: 08b36f3e73239b415b74c6ecc30ed65832d9ebd0

Summary: Makes it easy to split a Future into multiple Futures

Reviewed By: rongrong

Differential Revision: D3885897

fbshipit-source-id: 6ac9fb22444dd828fbdebb44b06bf3d93d0f7583