Summary: Avoid a needless use of the preprocessor in FixedString.h by using `kIsDebug` instead of the `NDEBUG` preprocessor macro in `checkNullTerminated`.

Reviewed By: yfeldblum

Differential Revision: D23411248

fbshipit-source-id: 78990ade25bcfa3956f917b2b285c096b76ecb09

Summary:
It's insufficient to infer support for `constexpr` `std::strlen` by merely testing that we're using libstdc++ on a compiler other than clang. Some other compilers besides gcc can be using libstdc++ that _don't_ have `constexpr` `std::strlen`.

Rather, use the compiler itself to detect support for either (a) the builtins, or (b) a `constexpr` implementation of the stdlb function, falling back to a custom `constexpr` implementation otherwise.

Also, handle MSVC, which supports `__builtin_strlen` but which doesn't support either `__has_feature` or `__has_builtin`.

Give `constexpr_strcmp` the same handling, but leave MSVC out of the fun because it doesn't provide `__builtin_strcmp`.

Also, remove the unnecessary include of `<type_traits>`.

Finally, make these functions `noexcept` for good measure.

Extra info: The overload sets in the `detail` namespace in this diff are a little magical. The first overload only compiles if (a) the string literal `"a"` can be `static_cast` to `const Char*` (that is, only if `Char` is `char`), and (b) if `FOLLY_DETAIL_STR???` yields a compile-time constant (so it can be used to initialize a non-type template parameter). If both of those things are true, that overload is preferred because the last argument requires no conversion. If either of those two conditions is false, that overload has a substitution failure and is removed from consideration. Then the second overload is selected.

Reviewed By: yfeldblum

Differential Revision: D23407997

fbshipit-source-id: f5838c578cb62b8fd777052223222882a6575429

Summary: References the folly logo from within README.md.

Reviewed By: yfeldblum

Differential Revision: D23490077

fbshipit-source-id: 103c0a7838f9f9982c542e5a82e8382a45d8a0b7

Summary: This adds the folly logo svg to the repo to make it available at a stable location.

Reviewed By: yfeldblum

Differential Revision: D23503775

fbshipit-source-id: 4ba0410c6f49d1ebc5b88c21c0ba8b60f9bf96d4

Summary: [Folly] Revise `is_constexpr_default_constructible_v` as a variable and as eager, and `is_constexpr_default_constructible` as a type and as deferred.

Reviewed By: Mizuchi

Differential Revision: D23371343

fbshipit-source-id: 192b5df78053c89acadab285b6dfb9ab52b14528

Reviewed By: yfeldblum, Mizuchi

Differential Revision: D23436113

fbshipit-source-id: 940cdca0d1d674ab4929b8f88ce48438fa0e4b25

Summary: Check result against kBlockSize

Reviewed By: kevin-vigor

Differential Revision: D23501893

fbshipit-source-id: b6a43474422049c93f02e0b5defd300a471bccf5

Summary:
Pull Request resolved: https://github.com/facebook/folly/pull/1438

The file `folly/experimental/io/test/IoTestTempFileUtil.h` does not have `pragma once` and can be included several times. It produces compilation errors.

Reviewed By: Orvid

Differential Revision: D23496733

fbshipit-source-id: 0309847f60992b21d07b2377d49539d78570fb09

Summary:
CMake's find modules may have target-based generator expressions, which get propagated to us when generating the pkg-config file.
CMake 3.19 introduces the TARGET argument to file(GENERATE), which allows resolving such generator expressions and will avoid future issues.
A workaround proposed by adriaandegroot is added for CMake 3.18.

Additionally changed list->string conversion to use list(JOIN) instead of string replacement.

Fixes https://github.com/facebook/folly/issues/1414.

Pull Request resolved: https://github.com/facebook/folly/pull/1433

Reviewed By: yfeldblum

Differential Revision: D23433365

Pulled By: Orvid

fbshipit-source-id: 6ef5f180e13b41f0c92137f53fd8c19ba6355dd6

Summary: [Folly] Fix possible UB in `constexpr_strcmp` since signed arithmetic wraparound is undefined.

Differential Revision: D23435902

fbshipit-source-id: f71103f58f9a1a69dbc7fa462703605d1fc78348

Summary:
Because of https://github.com/google/sanitizers/issues/1116, any races detected during pthread_atfork deadlock the process.
For forks issued from folly we can use an instrumented fork version to minimize the amount of code running via pthread_atfork.

Reviewed By: yfeldblum

Differential Revision: D23281093

fbshipit-source-id: fd4d3bf06b7992ff314f631ed899854a8b3f6c4b

Summary: [Folly] Cut `FOLLY_CREATE_HAS_MEMBER_TYPE_TRAITS` since its margin of utility is too small given `folly::is_detected`.

Reviewed By: Mizuchi

Differential Revision: D23371271

fbshipit-source-id: 6db49163d54ffd4d862bb98345d0e71b4d114674

Summary: When setting halt_on_error to 0 (which is the default setting now for TSAN in fbcode because we want to catch all bugs), a deadlock does not immediately cause an issue. So we include exit(0) as part of the death test to handle that case.

Reviewed By: yfeldblum

Differential Revision: D23493015

fbshipit-source-id: fb4910edddab11e1cd00e402b6b7350a6dc941a7

Summary:
We use Re2 in D22877942 for parsing multiple path prefix data fetch logging,
this introduces the dependency for eden's opensource builds.

Reviewed By: chadaustin

Differential Revision: D23431175

fbshipit-source-id: 44b399e92cb89ba1403295ecd10bc8f8d769b02c

Summary: [Folly] Simplify the fallback implementations of `constexpr_strlen` and `constexpr_strcmp` by taking advantage of C++14 `constexpr` syntax.

Differential Revision: D23416900

fbshipit-source-id: 93a969282faa61b3c9ff8e75519ad4e6edd71e4e

Summary: TSAN just needs more stack doing this...

Reviewed By: yfeldblum

Differential Revision: D23484864

fbshipit-source-id: e5412982349f73f8ead795403dfbde2830f4e5fd

Summary: Apparently the code says, being signal unsafe is OK because the signal is created with raise(). So let's just skip that test under TSAN.

Reviewed By: yfeldblum

Differential Revision: D23484012

fbshipit-source-id: 697234b9f57db97c6c6aaf8131058d3ecec3d059

Summary:
To preserve void type in roundtrip
Doing this generically is pretty gross (you need to check if awaiter_type<decltype(co_viaIfAsync({}, SemiAwaitable))> has a member await_resume_try), while the cost of adding explicit overloads is low as there are only two types we care about, so I chose to do it that way.

Reviewed By: yfeldblum

Differential Revision: D23407270

fbshipit-source-id: cc952e2d8fa4297dbe363e22e99192fdf858134f

Summary:
The Timekeeper parameter can be used to pass in manually-controlled time-sources
for testing purposes if required.

Reviewed By: yfeldblum

Differential Revision: D23386677

fbshipit-source-id: bea09292b00f6cd018568d26e5409d2c7ff01dbe

Summary: [Folly] Test `constexpr_strlen`, `constexpr_strcmp` fallback implementations alongside the main implementations, since the main implementations may fall back to the fallback implementations on some platforms but not on others, and we may only be testing on the other platforms.

Differential Revision: D23432301

fbshipit-source-id: 271705cb8c2b1ab6d11c1be20e2c3023cacab583

Summary: [Folly] Cut `FOLLY_CREATE_HAS_MEMBER_FN_TRAITS` since it is unused and does not match the current invoker model, replacing uses which need it with `FOLLY_CREATE_MEMBER_INVOKER`.

Reviewed By: vitaut

Differential Revision: D23371070

fbshipit-source-id: 7fb0f5af21321a5056e06933ebd364a0a48a8fa1

Summary: Reduce boilerplate when defining simple coroutines, e.g. in tests

Reviewed By: yfeldblum

Differential Revision: D23404552

fbshipit-source-id: a19e9cb6640e3897d3c166499014ebe4c19fbf04

Summary: D9312236 (https://github.com/facebook/folly/commit/bc16b096b1f6659e29379a650998bbfcf0c03eca) made these tests conditional on using libstdc++, but the header that defines the macro is not included prior to the `#ifdef`, so the tests (and benchmarks) are disabled unconditionally.

Reviewed By: yfeldblum

Differential Revision: D23469536

fbshipit-source-id: 2ab0b2d28748419d88e946eff9b09b98d361dedb

Summary: [Folly] Revise `is_transparent_v` as a variable and as eager, and atop `is_detected`, and `is_transparent` as a type and as deferred.

Reviewed By: Mizuchi

Differential Revision: D23367991

fbshipit-source-id: be30184b04e2a1977db3faccd57e947dd33282ce

Summary:
Change name of warning_list_too_large to hazptr_warning_list_too_large for consistency with other hazptr warning functions.

Add missing  FOLLY_EXPORT.

Reviewed By: yfeldblum

Differential Revision: D23436826

fbshipit-source-id: 149c62c9d1cd3320ef525a90c0b591b274228054

Summary: [Folly] `is_detected`, for a common pattern around `void_t`, backported from Library Fundamentals TS v2.

Reviewed By: Mizuchi

Differential Revision: D23367990

fbshipit-source-id: 3a0e9a5b7eb668f872ce699757e32bb620bb5404

Summary: Add support for microsecond intervals in the function scheduler

Reviewed By: arushiagg

Differential Revision: D23433411

fbshipit-source-id: 39d201feaaed8007ec880a799129ed94bedd827a

Summary: Add io_uring registered buffers support

Reviewed By: kevin-vigor

Differential Revision: D23421043

fbshipit-source-id: b9c6a4bbd7a6b6cc580b1e3f64320d9e59d04ab2

Summary: [Folly] Revise is_instantiation_of_v as a variable and as eager, and is_instantiation_of as a type and as deferred.

Reviewed By: Mizuchi

Differential Revision: D23367989

fbshipit-source-id: bf6ebd74b8e7758818dfcebd04152e1297bc99e4

Summary: These lightweight functions are useful on their own, but were tied to `Benchmarking.h` & all their dependencies.

Reviewed By: yfeldblum, ot

Differential Revision: D20239087

fbshipit-source-id: 644601b6f869191db1492d0738f3af723b9e0f4b

Summary: Fix overspecified LoggerTest.

Reviewed By: yfeldblum, simpkins

Differential Revision: D23425421

fbshipit-source-id: ecfd7d0e73555b3a94a81b54ffd1287bf9664697

Reviewed By: xavierd

Differential Revision: D23434438

fbshipit-source-id: 813f987cf62e72c0b6704b31e6e9168006735b6f

Summary: Original commit changeset: 10f18d7b774c

Reviewed By: arushiagg

Differential Revision: D23431208

fbshipit-source-id: d2c79f81fd0ada202dc2eaa96b0f061828ca107e

Summary: Many unit tests ended up already depending on the scheduling order. Relax the logic to only reschedule once we reach a high nesting depth.

Reviewed By: iahs

Differential Revision: D23415806

fbshipit-source-id: dde682293ded0061cf331fa5f46e1f6b55928a3e

Summary:
std::iterator was deprecated in C++17, so define the iterator trait
properties directly. This fixes warnings during compilation with Clang
on Windows.

Reviewed By: yfeldblum

Differential Revision: D23353495

fbshipit-source-id: 7c6c0b7fb175251260e5b519ce98bd679b6c99c4

Summary: Add support for async range submit

Reviewed By: yfeldblum

Differential Revision: D23389493

fbshipit-source-id: 7171893a2eeccc20fcdd625e98f88d365027c930

Summary: TSAN breaks symmetric transfer behavior in compiler. Work around it by rescheduling work on executor when possible.

Reviewed By: yfeldblum

Differential Revision: D23391328

fbshipit-source-id: 7b25a0c89664ca14114f8ae0dc650ff9bb786fe1

Summary: Switch from VLA to folly::small_vector

Reviewed By: yfeldblum, ot

Differential Revision: D23391426

fbshipit-source-id: c6c61f3f0eef5b6e71ad3a639fcfdb4fa1b7268e

Summary: Add support for microsecond intervals in the function scheduler

Reviewed By: yfeldblum, Mizuchi

Differential Revision: D23153179

fbshipit-source-id: 10f18d7b774c47659fe8191f8d92dca341e1cf97

Summary: [Folly] Remove the guard around `tag`, the inline variable of type `tag_t`.

Reviewed By: Mizuchi

Differential Revision: D23370037

fbshipit-source-id: 59a48d834904b7e503f807c62fff8534568c9a0a