Summary:
Remove the standalone fb-mercurial-rust target that was an internal-only
dependency for the Eden build.  This build step is now done entirely in the
Eden build.

Reviewed By: fanzeyi

Differential Revision: D18623943

fbshipit-source-id: c62a1155ddd1c0a6b2270c472176ba25194c6145

Summary:
Re-implementation of fiber gdb integration.  All previous functionality still works as well.

Commands:
* `fiber`: switch to fiber by address, alias, or assigned short id
* `fiber apply`: run arbitrary gdb commands for each specified fiber (or "all")
* `fiber deactivate`: switch back to normal thread behavior
* `fiber name`: assign or clear an alias to a particular fiber
* `info fibers`: print out each fiber manager and fiber, with ids and current frame info

Parameters:
* `fiber info-frame-skip-words`: the "uninteresting" function matches to skip frames of when showing fiber info
* `fiber manager-print-limit`: limit of the number of fibers displayed when printing a fiber manager

Fibers are assigned ids of the form "<MANAGER_ID>.<FIBER_ID>".  When specifying fibers for `info fibers` or `fiber apply`, you can specify any number of space-separated fiber ids, and additionally you can specify a manager id by itself to refer to all fibers in that manager.

When printing info with `info fibers`, every stopped fiber will be in `folly::fibers::FiberImpl::deactivate()`, which isn't particularly useful.  To give more-useful information, it will skip past all frames whose function names include the strings "folly::fibers" or "wait" and print the first non-matching frame's information instead.  The `fiber info-frame-skip-words` parameter defines the strings to match on, specified as a space-separated list of words.

Due to gdb limitations, the selecting a fiber "masks" the currently selected thread, and to see the current thread again you will need to run `fiber deactivate`, same as before.

Reviewed By: andriigrynenko

Differential Revision: D18342802

fbshipit-source-id: 5b2204bb09eca4c8f977c6c17b0348e39465dff6

Summary:
- Added sai to getdeps
- added SAI to FBOSS as a dependency
- Included path of SAI headers to FBOSS's cmake file.

Reviewed By: shri-khare

Differential Revision: D18629127

fbshipit-source-id: 119a6b7f2b64bd84414d9e16a903bc8df48a35e7

Summary:
The mutable global executor is problematic: it defaults to Inline, and it is constructed off of an error-prone weak_ptr and it returns a shared_ptr. A KeepAlive-based global immutable executor is a cleaner default.

This change adds immutable global executors, and moves the default executors into separate singletons for cleaner interaction between the mutable executor and the underlying default immutable ones, including the default inline global cpu executor.

Reviewed By: andriigrynenko

Differential Revision: D18513433

fbshipit-source-id: 0ad825c34cc7ba935f57ff81adb8cff3bf001a45

Summary:
With THP set to madvise, page faults on these pages will block until a
huge page is found to service it. However, if memory becomes fragmented
before these pages are touched, then we end up blocking for kcompactd to
make a page available. As this increase pressure, oomd comes in and kills
us :(. So, preemptively touch these pages to get them backed as early as
possible to prevent stalling due to no available huge pages.

Reviewed By: hnaz, interwq

Differential Revision: D18579722

fbshipit-source-id: 5f54676a128207026cb16b9cdc03a055cbb1f9b9

Summary: This diff disables the purging of huge pages and hence they will never be freed and will be counted towards the RSS of the process. This was done to ensure that we don't block on madvise call to get the huge pages and increase memory pressure on the system.

Reviewed By: gdankel

Differential Revision: D18607196

fbshipit-source-id: 79e483a715290fdfbdd1963433ec3918561a0e0e

Summary:
Clang 7 seems to have trouble with `FOLLY_CREATE_MEMBER_INVOKER()` on Windows targets if the invoker's name is the same as the invocable name. It's spewing `-Wmicrosoft-explicit-constructor-call` warnings and the `static_assert`s in LockTraits.h are failing. As a workaround, we can rename the LockTraits.h invokers to use an `_invoker` suffix.

See https://gcc.godbolt.org/z/j4qRd9 for a demonstration of the issue.

Reviewed By: vitaut

Differential Revision: D18626335

fbshipit-source-id: c9147daaa10b02b0692c32963f9ede8cc645e329

Summary:
Include tools/lfs in the shipit path map for now, since it is needed to
download vendored Rust crates on internal builds.  Also correctly indicate
that the fb-mercurial* dependencies also apply only to internal builds.

Reviewed By: chadaustin

Differential Revision: D18621421

fbshipit-source-id: 74f00bf318ff9aefdca8696a61a8f33587749e66

Summary:
Automatically detect the `--facebook-internal` flag based on the current
repository project name.

Reviewed By: wez

Differential Revision: D18621358

fbshipit-source-id: f2b3018169b151811eec455863a8bfc17667d4d8

Summary:
Dovetailing off of https://github.com/facebook/folly/issues/1262 ; Folly's dependency on `fmt` isn't explicitly mentioned nor are from-source install instructions provided. This PR adds a short section to the README describing how to build and install fmt from source.
Pull Request resolved: https://github.com/facebook/folly/pull/1263

Reviewed By: vitaut

Differential Revision: D18622693

Pulled By: yfeldblum

fbshipit-source-id: e43ab8c5524df9decc79cdd0cb2aea3d88826617

Reviewed By: yfeldblum

Differential Revision: D18614792

fbshipit-source-id: 9b77ae8aba9153c9051dd5935cda807dfad4e6e2

Summary: [Folly] `FOLLY_CREATE_STATIC_MEMBER_INVOKER`, for creating invoker types which can invoke class static members.

Reviewed By: vitaut

Differential Revision: D18035183

fbshipit-source-id: 2bcab988f684042b26843d5fe0a13ad7c549e43a

Summary:
Since D18140137 `reset()` doesn't perform any data reads, so we can simplify the implementation of the `jump*` functions to just reset the reader in case of a backward jump. The only tricky case we need to handle is when `jumpTo` is called from the middle of a run of identical values.

Delegating to `skip*` the additional benefit of inheriting the optimizations for small forward skips.

Differential Revision: D18496743

fbshipit-source-id: 73dc8b21534fba90f1ac2a924a7cebc56ffaba94

Summary: [Folly] `to_narrow`, for explicitly performing a possibly-narrowing integral conversion without specifying the destination type. Does not permit changing signs.

Reviewed By: luciang

Differential Revision: D18498269

fbshipit-source-id: be597daf981376758effa0b3721cad67a49c9ef1

Summary:
1) SharedPromise is semantically a regular Promise one can get multiple Futures off. One would expect that all methods which are const in Promise to also be const in SharedPromise - but they are not because their implementations needs using a mutex.
2) Semantically, `SharedPromise::getFuture()` and `SharedPromise::getSemiFuture()` do not change the observable state of the object.
3) As real-life consequence,  these non-const `SharedPromise` methods become viral in downstream code which then has to hack around it in downstream `const` methods by marking the SharedPromise instance mutable. That solution leads to the program being less const-correct than it should be, as now the type system allows `const` methods to reassign or `setValue` the SharedPromise.

This diff changes `hasResult`, `isFulfilled`, `size()`, `getFuture()` and `getSemiFuture()` to be `const`. In order to achieve that, the private fields `mutex_` and `size_` had to be marked `mutable`.

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D18565877

fbshipit-source-id: ff63a48c02235f72c5b0191423ae68f7b7c42fb3

Summary:
On Windows, compile a small C executable to prepend to the zip file, to allow
the resulting executable files to be run directly on Windows, without needing
to explicitly invoke the Python interpreter to run the output file.

Reviewed By: wez

Differential Revision: D17733616

fbshipit-source-id: 989a93851412d0bbe1e7857aa9111db082f67a4c

Reviewed By: yfeldblum

Differential Revision: D18449687

fbshipit-source-id: 6d630cef35132abb157e80d02ad2b6dee7268fce

Summary: Expose the call to folly::Optional::value_or() in the Cython bindings

Reviewed By: nanshu

Differential Revision: D18526111

fbshipit-source-id: f2694ca589bf73653bc86d5c98b52e15406bed77

Summary:
Add basic wrapper to support wrapping C++ APIs that contain
folly::Function in their interfaces. Does not support calling operator() from
within Cython, but only pass through of folly::Function<> to such APIs.

Reviewed By: nanshu

Differential Revision: D18526112

fbshipit-source-id: d219d480e59464099a109e5ef30d015151588b1f

Summary:
Add new cython wrapper class to expose folly::Expected to other
cython_libraries

Reviewed By: jkedgar

Differential Revision: D18523642

fbshipit-source-id: 0dfb4820b2613361b7c1af05b89b5231a1bfecbc

Summary:
EliasFanoCoding supports sequences with duplicate values, but there is no test coverage and the behavior of some corner cases (`skipTo` and `jumpTo` from the middle of a run) is not documented.

This diff adds coverage and documentation.

Reviewed By: yfeldblum

Differential Revision: D18496744

fbshipit-source-id: 00e112a902a8b11ac9601520b858172a1d2c0f57

Summary:
Now that fmt is available in Folly builds (D14813810), use it to reduce binary code size in Folly Logger. This is done by moving most of the formatting logic behind the type-erased `vformat` API. Previously it was instantiated for all combinations of formatting argument types used in calls to `FB_LOGF` and `XLOGF` in a program.

The effect of this change can be illustrated by looking at symbol sizes as given by `nm -S -td` for the following test function:

```
void test_log() {
  FB_LOGF(logger, WARN, "num events: {:06d}, duration: {:6.3f}", 1234, 5.6789);
}
```
compiled in `opt` mode.

`nm` before:

```
0000000004236736 0000000000000231 T test_log()
0000000004236992 0000000000001002 W std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > folly::LogStreamProcessor::formatLogString<int, double>(folly::Range<char const*>, int const&, double const&)
```

`nm` after:

```
0000000004237536 0000000000000231 T test_log()
0000000004237792 0000000000000251 W std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > folly::LogStreamProcessor::formatLogString<int, double>(folly::Range<char const*>, int const&, double const&)
0000000004238048 0000000000000740 W folly::LogStreamProcessor::vformatLogString[abi:cxx11](folly::Range<char const*>, fmt::v5::format_args, bool&)
```

Before we had one 1002 byte instantiation of `formatLogString<int, double>`. With this change it was reduced 4x to 251 bytes and non-template function `vformatLogString` was added which is shared among all logging calls. The size of `test_log` remained unchanged. There are even bigger savings from Folly Formatter instantiations which are no longer needed, e.g.

```
0000000004238032 0000000000001363 W _ZNK5folly13BaseFormatterINS_9FormatterILb0EJRKiRKdEEELb0EJS3_S5_EEclIZNKS7_8appendToINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEENSt9enable_ifIXsr12IsSomeStringIT_EE5valueEvE4typeERSH_EUlNS_5RangeIPKcEEE_EEvSK_
```

So in total this change results in ~5x per-call/instantiation binary size. It is possible to reduce binary size even further but it is not done in the current diff to keep it manageable.

In addition to binary size improvements, switching to fmt will potentially

* allow catching errors in format strings at compile time,
* simplify future migration to C++20 [`std::format`](http://eel.is/c++draft/format).

Reviewed By: simpkins

Differential Revision: D15485589

fbshipit-source-id: 06db4436839f11c2c3dbed7b36658e2193343411

Summary:
When we detect that we are building out of the fbsource
monorepo internal to FB, pre-set some environment variables to help
projects detect our internally pinned versions of node and yarn.

Previously, the detection logic was deciding that the `yarn` shell
script was the executable to invoke, but since that is a bash script
it would fail to spawn.

Reviewed By: simpkins

Differential Revision: D18523871

fbshipit-source-id: b932d2b0ccd7b79d6f9cd74d363bc426c288e38f

Summary: Original commit changeset: 6021479ab36c

Reviewed By: d4l3k

Differential Revision: D18535981

fbshipit-source-id: 4f9e5da29ed6d9bae04f29bcf273b41d39cc5754

Summary: Original commit changeset: a1af88dfa1b6

Reviewed By: d4l3k

Differential Revision: D18535282

fbshipit-source-id: 16da3084a519f978bf33f197ab7f937b61bb9d07

Reviewed By: yfeldblum

Differential Revision: D18528940

fbshipit-source-id: 288abb510535540698416ac046c1057e110e4478

Summary: [Folly] Erase the invokers. A catchy title, but forcibly inline the invoker call operators.

Reviewed By: vitaut

Differential Revision: D18035184

fbshipit-source-id: 5cf57d785523904a5260f7ed24c9ed34148370eb

Summary:
[Folly] Fix possible segv in `Function` shared proxy when invoking the (public!) `nullptr`-taking ctor.

This proxy is used when converting `folly::Function` to `std::function` with shared state.

Reviewed By: ot

Differential Revision: D18517365

fbshipit-source-id: c414c1d1ae2b4f30ffa3269b216be07fedbf838c

Summary: [Folly] Avoid overloading other names from within detail namespaces - prefer renaming or at least mangling.

Reviewed By: Orvid

Differential Revision: D18502700

fbshipit-source-id: a4f455db69396962b298c6291929f1eb152e1576

Summary:
The instruction is identical to the x86 one. First introduced in MIPS32r2.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Pull Request resolved: https://github.com/facebook/folly/pull/1257

Reviewed By: Orvid

Differential Revision: D18467031

Pulled By: yfeldblum

fbshipit-source-id: 04b695167184db8ef71df47e82e414793ddb0ab9

Summary:
[Folly] `FOLLY_CREATE_FREE_INVOKER` and `FOLLY_CREATE_MEMBER_INVOKER` to replace `FOLLY_CREATE_FREE_INVOKE_TRAITS` and `FOLLY_CREATE_MEMBER_INVOKE_TRAITS`.

New approach: just emit an invoker object. For the traits, just use the normal traits instead of rewriting them, or use `invoke_traits` to get an invoke-traits type specialized to the invoker.

Reviewed By: vitaut

Differential Revision: D18079121

fbshipit-source-id: 8258c36b8ba6ee62a8ecc104cd1b6281d313960f

Summary:
Found with modernize-use-auto
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Pull Request resolved: https://github.com/facebook/folly/pull/1256

Reviewed By: Orvid

Differential Revision: D18421629

Pulled By: yfeldblum

fbshipit-source-id: c49418a3b3413acd1506c550af44c806332eedb8

Summary:
This diff adds support for optionally setting an obj batch such that objects retired to the batch bypass the batch and are directly pushed to the domain.
This is useful in cases where the benefits of earlier reclamation outweigh the benefits of amortizing the cost of pushing objects to the domain.

Reviewed By: davidtgoldblatt

Differential Revision: D18114444

fbshipit-source-id: a1af88dfa1b601827b2f71e700fb1dfcb08e513c

Summary:
Fix -Wshorten-64-to-32 compile warning treated as error

(Note: this ignores all push blocking failures!)

Reviewed By: nbronson

Differential Revision: D18493255

fbshipit-source-id: 10a2a576c7f587d02a61860285171f2c5f0534ad

Summary:
Allows a category to be configured to selectively propagate messages to its parent category.

I preferred this over a simple `true`/`false` filter because it can be useful to have one log file for all DBG logs from a component while still limiting it to `INFO` or whatever in the main application log file.

Reviewed By: simpkins

Differential Revision: D18360804

fbshipit-source-id: a45098c81fdc8b984e440748880e8943df95acd2

Summary:
Allow hazptr_obj_batch-es to outlive the default domain.

Background: Until now it was expected that batches are destructed before the destruction of the default domain. This may be restrictive to good use cases.

This diff removes the above mentioned restriction and gives hazptr_obj_batch::shutdown_and_reclaim() to decide whether or not to access the default domain by supporting a singleton bool in default_hazptr_domain_alive() that could be made to outlive the default domain by calling that function before constructing the user object that may outlive the default domain.

Reviewed By: aary

Differential Revision: D18297698

fbshipit-source-id: 6021479ab36ce86d2c411fd71974fde47f7502a2

Summary: In a coroutine returning a `coro::Task<T>`, make `co_return {};` return a default-constructed `T` rather than a default-constructed `folly::Try`.

Reviewed By: yfeldblum, andriigrynenko

Differential Revision: D18466785

fbshipit-source-id: ed20f0f5ad98a0ef8e693e490417a7e36f706822

Summary: Newer CRT versions have changed how certain definitions were gated, so we need to update to support them.

Reviewed By: akrieger, guangyfb

Differential Revision: D18435320

fbshipit-source-id: 40ffc57ed1fe0ad1b01ab834aed9762bde5563cb

Summary:
Not supported under ARMv6 and below.
Pull Request resolved: https://github.com/facebook/folly/pull/1176

Reviewed By: yfeldblum

Differential Revision: D18145021

Pulled By: Orvid

fbshipit-source-id: 21796e225f650038479d1f5a858313dab0477e66

Summary: As title.

Reviewed By: yfeldblum

Differential Revision: D18351375

fbshipit-source-id: 594270e7b6b7056f7223fa7575ee33fed8f7d266