Summary: [Folly] Just use `constexpr` keyword in `folly/lang/Bits.h` - since they are now template functions, `constexpr` is okay even when all instantiations would be non-`constexpr`.

Reviewed By: Orvid

Differential Revision: D9934124

fbshipit-source-id: cdf4fc87262a058af6f63e28bb2c390e44f2cad0

Summary:
`hash_range(c.begin(), c.end()` combines hashes of individual elements of a
container in an ordered manner. This diff provides the equivalent for
unordered containers.

Unlike `hash_range`, `commutative_hash_combine_range` defaults to `folly::Hash`
as its hasher; it mixes the individual hash if the `hasher` is not deemed
avalanching.

It uses a commutative accumulator described in this paper:
https://www.preprints.org/manuscript/201710.0192/v1/download
In the experiments in the paper, the symmetric polynomial yielded a better
spread of hash values and lower collision rates than `+` or `xor`.

Reviewed By: yfeldblum

Differential Revision: D9688687

fbshipit-source-id: c812b25975a53a868d98f78645146cb8bdbb5c32

Summary:
`IOThreadPoolExecutor.pickThread()` has some sketchy behavior where, if the
threadpool has no threads, it returns `*thisThread_` unconditionally. My read
is that this can happen only in two cases.

First, `getEventBase` could be called from outside the threadpool while the
threadpool has no threads (either because it was stopped or because somebody
set it to 0 threads.) In this case, `*thisThread_` will be nullptr and
`getEventBase` will try to immediately dereference it, (hopefully) crashing.

Second, `getEventBase` could be called from inside the threadpool, but from a
thread which is shutting down. This is also somewhat dodgy, because by the time
we get to this case (`me && !contains(threadList_.get(), me)`), stopThreads
will have already called terminateLoopSoon on the evb. While it would still be
possible to use the evb safely (in the sense that one could write a program
which does not hit undefined behavior), I think it'd be strongly dependent on
the way IOTPE and EventBase are currently implemented and therefore probably a
bad idea.

I don't have the bandwidth to really dig into this now and figure out what the
correct behavior is, or how to fix people who might be relying on the broken
one. But I figure I can at least leave a comment behind that this is something
maybe worth looking into.

Reviewed By: meyering

Differential Revision: D9754314

fbshipit-source-id: 6851d49e634707cacc803a95763eda023967b932

Summary: Because reasons :(

Reviewed By: yfeldblum

Differential Revision: D9923447

fbshipit-source-id: 7a3a9ab86764dc5c7f5b70f2f728aec8b67bdf1f

Summary:
This diff adds spurious rehash at places where the caller should
not be assuming reference (unless guaranteed) or iterator stability,
allowing ASAN to detect these problems.  Under ASAN it also junk-fills
deleted value_type instances that can't be immediately deallocated.

Reviewed By: yfeldblum

Differential Revision: D9826273

fbshipit-source-id: 2d543473b17ffd7debb52082a3e72842121ece1a

Summary:
An allocator that uses a jemalloc arena backed by 2MB huge pages.

This uses the jemalloc extent hooks to let jemalloc hand out memory backed by huge pages.
The huge pages are allocated when init(int nr_pages) is called, and does not grow (although extending it to grow in the future should be fairly straightforward).

madvise is used to mark the pages as huge. It does not guarantee success, and the only way to tell is by looking at /proc/<pid>/smaps and the total huge pages in /proc/<pid>/status.

The HugePageAllocator can be used as template parameter for stl and folly collections.

Reviewed By: yfeldblum

Differential Revision: D9297627

fbshipit-source-id: 734ca1b19972a8b5d7a12ee60cba1ffa3da50dc2

Reviewed By: ngoyal, mingtaoy

Differential Revision: D9862034

fbshipit-source-id: ce1f00fe12c52e755ff67775e980ff3ff4227bbf

Summary: No semantic changes. Reordering, and removal of an unnecessary fwd decl

Reviewed By: nbronson

Differential Revision: D9851048

fbshipit-source-id: dd306435ad2f77e42f74dc29b19ec5d6fe09ae2a

Summary: It's no longer needed, and was a pain to support properly.

Reviewed By: yfeldblum

Differential Revision: D9846778

fbshipit-source-id: b727a3459efed4e6df3db50f8d7fe0963c3608f8

Summary: Handle the dlopen static initialization

Reviewed By: yfeldblum

Differential Revision: D9847032

fbshipit-source-id: 089628ef88cf72d189a8904a3f2231f1affc764c

Summary: It's no longer needed.

Reviewed By: yfeldblum

Differential Revision: D9847073

fbshipit-source-id: 072f4e5fc207ab199689e42c4f492d4fcb67aa8e

Summary:
The last bits of pthread needed for thrift.
Also define PTHREAD_MUTEX_NORMAL properly.

Reviewed By: yfeldblum

Differential Revision: D9846774

fbshipit-source-id: 124013c6df07f9faa214b77fa8ebe8b37d8f460e

Summary: [Folly] Fix `rcu_domain` move-assignment pointer copy which seemingly should be a pointer exchange.

Reviewed By: magedm

Differential Revision: D9846892

fbshipit-source-id: ef3a113780af7456d66dacd376b3bf43670fcb9e

Summary: Documentation has drifted out of date with updated plan. This brings the core parts into line.

Reviewed By: yfeldblum

Differential Revision: D9833211

fbshipit-source-id: b372f9cfc0c787feab86490beeb1dcaa290e8566

Summary:
[Folly] Tweak `ThreadLocal` inlining.

Shrinks overly-large generated code for `ThreadLocal::get()`.

Reviewed By: luciang

Differential Revision: D9732837

fbshipit-source-id: 71eb10d9759e1fa17248e0feed75f610948afe21

Summary: [Folly] Tweak `ThreadLocal` fast-path functions. Mostly code golf.

Differential Revision: D9732836

fbshipit-source-id: fc48a7c067c6961413e6aa94106ae26f87d3d603

Summary: Let's see what breaks.

Reviewed By: yfeldblum

Differential Revision: D9569029

fbshipit-source-id: 2edbafc018ec70d8640f2e28d35735089c9eb69d

Summary: This only exists for perf comparisons, and has been unused for years.

Reviewed By: yfeldblum

Differential Revision: D9846361

fbshipit-source-id: ad28ff12fe16deb0ceee50ce6c098f234e8f9692

Summary: Make comments consistent with the updated recommendations where it makes sense.

Reviewed By: yfeldblum

Differential Revision: D9833280

fbshipit-source-id: 8de3372b013a322e57cd2d54a512d75bf963d1a5

Summary:
lock bts and lock btr with the varying lengths turn out to be faster than
a single CAS instruction

fetch_set uses lock bts and fetch_reset uses lock btr when possible.
std::atomic::fetch_or and std::atomic::fetch_and with a mask otherwise

Reviewed By: yfeldblum

Differential Revision: D9652759

fbshipit-source-id: e6d10fdb119a10e15e32131c7389f1d4203a0d91

Make rcu_default_domain_ folly::Indestructible<rcu_domain<RcuTag>> to avoid asserts on _dl_open/_dl_init __static_initialization_and_destruction_0

Summary: Make rcu_default_domain_ folly::Indestructible<rcu_domain<RcuTag>> to avoid asserts on _dl_open/_dl_init __static_initialization_and_destruction_0

Reviewed By: yfeldblum

Differential Revision: D9845303

fbshipit-source-id: e858e86a6f7885bf6a3ad8d5e957ee947a5ce2b3

Summary: Because explicit is better.

Reviewed By: sathyaphoenix

Differential Revision: D9834733

fbshipit-source-id: 6e6af1d5215021db522284b6c58c753522df20df

Summary: I want to use TestLogHandler::getMessageValues with a const TestLogHandler reference. Mark getMessageValues as const so it can be called on a const TestLogHandler. getMessageValues doesn't mutate class state, so this should be safe.

Reviewed By: chadaustin

Differential Revision: D9815552

fbshipit-source-id: 275625d1a001fe536586229228eb2c9eee7e6330

Summary: The pthread library we were using is getting to be annoying so just implement things ourself.

Reviewed By: yfeldblum

Differential Revision: D9777661

fbshipit-source-id: fb53d0d369ed27a869e9f6285a548778c3492f2e

Summary:
It first looks for the name, then looks for a section with that
offset. But strings can be overlaid; eg .rela.debug_info and .debug_info
can be overlapped, so we won't find .debug_info at all.

Instead, just iterate the sections checking to see if the name matches
the one we're looking for.

Reviewed By: ricklavoie, palmtenor

Differential Revision: D9809817

fbshipit-source-id: b165719c6f9004ecc964096677114bce357ece30

Summary:
Pull Request resolved: https://github.com/facebook/folly/pull/932

As title.

Reviewed By: yfeldblum

Differential Revision: D9817328

fbshipit-source-id: 261c68f21316e91f3ed752c4aeab9e9c95dfe16d

Summary:
toAppend support DoubleToStringConverter::SHORTEST_SINGLE for float type.
Pull Request resolved: https://github.com/facebook/folly/pull/928

Reviewed By: yfeldblum

Differential Revision: D9790564

Pulled By: Orvid

fbshipit-source-id: b38d6542518aa0ed7f2b0e222e9870bb5f3a51e5

Summary: As title.

Reviewed By: JohnRambo

Differential Revision: D9820130

fbshipit-source-id: 58128c561825681d463759da33be94b861057f2e

Summary:
The `__cpuid()` and `__cpuidex()` instructions are only available on
x86 and x64 https://fburl.com/ejw47bcl.

Reported in zstd [Issue#1313](https://github.com/facebook/zstd/issues/1313).

Reviewed By: Orvid

Differential Revision: D9800189

fbshipit-source-id: 8e846d2220e544b16547db16d21c7c7b0e21cefb

Summary: MSVC wants template arguments to have exact same names in forward declarations.

Reviewed By: yfeldblum

Differential Revision: D9780751

fbshipit-source-id: 18cc529603c128e4c5d5a20bc61e0e44c0d0240c

Summary:
- GLock<SpinLock> -> GoogleSpinLockAdapter
- Duplicated BENCH_BASE -> BENCH_REL

Reviewed By: yfeldblum

Differential Revision: D9803057

fbshipit-source-id: a69961f6d429eadca6feaacd0d5d999b55d13300

Summary:
`align()` was private, so the converting construct didn't have access
to `other.align()`.

Reviewed By: yfeldblum

Differential Revision: D9785137

fbshipit-source-id: e64a66eccd8a8b28db27873c0aaa7305b642c926

Summary: [Folly] Fix weird formatting of `break` after switch-case-close-brace.

Reviewed By: Orvid

Differential Revision: D9796573

fbshipit-source-id: 5f392e9fcf33be24acb9fc7a79bdf9ca846fd33c

Summary:
[Folly] Find `libiberty` headers in subdir also.

Fixes #792.

Reviewed By: simpkins

Differential Revision: D9330225

fbshipit-source-id: 6a9c3aaf4e76e3b5c8947cb15d0b43ed6cbcc778

Summary:
Warning: https://msdn.microsoft.com/en-us/library/cxdxz3x6.aspx

Provide matching placement delete operator to avoid the false-positive MSVC warning about memory leak when exception is thrown inside the constructor.

Reviewed By: yfeldblum

Differential Revision: D9773561

fbshipit-source-id: e6c4ab1d230e567491271c4cc2c23cd98469e672

Summary: No semantic changes

Reviewed By: yfeldblum

Differential Revision: D9788374

fbshipit-source-id: e619bc19d6064899ce61acc6b67b8b8a8f92101d

Summary: [Folly] Revise the `kSelectInByte` comments - hopefully be clearer and include an example.

Reviewed By: luciang

Differential Revision: D9780161

fbshipit-source-id: 6e9b5798afed9fe161b527ab597852232c278564

Summary: [Folly] Compute `kSelectInByte` table at compile time rather than hardcoding the resulting precomputed table.

Reviewed By: luciang

Differential Revision: D9627807

fbshipit-source-id: 01fbb07dd14aac4b84ad72bac10a12d3657be589

Summary:
Currently malloc(goodMallocSize(x)) will succeed when x is larger
than the maximum possible allocation supported by jemalloc.  This is
not desirable.  Currently goodMallocSize(x) returns 0 if x is too large,
but 0 is a valid argument for malloc and causes a 1 byte allocation.
This diff causes goodMallocSize(x) to return x in that case, which will
cause the subsequent malloc to fail.  The caller may catch that failure
or crash immediately, but those are both preferrable to returning a
pointer to a valid 1-byte allocation.

Reviewed By: al13n321

Differential Revision: D9778137

fbshipit-source-id: 3eb8da72d6240b28da85483f0d91653f5e04b333

Summary:
[Folly] Refactor `StaticSingletonManager`.

* Move implementation to `.cpp`.
* Remove all `#include`s possible from `.h`.
* Control inlining.

Differential Revision: D9734721

fbshipit-source-id: 82a1cda187674a6bb62e14a80431aeb07c65156c