Summary:
encodeVarintToIOBuf and decodeVarintFromCursor are not used when
FOLLY_HAVE_LIBLZMA and FOLLY_HAVE_LIBLZ4 are false, which will trigger
-Werror,-Wunused-function on compile on mobile.

Test Plan: unit test

Reviewed By: seanc@fb.com

Subscribers: meisner, trunkagent, seanc, folly-diffs@, yfeldblum

FB internal diff: D1864016

Signature: t1:1864016:1424702813:75535ea92ac16385ce5c272d93bba507ccbb67a1

Summary:
Previously leak-fatal could never happen because we were incorrectly checking singleton state.
Sending this diff to see how many tests will actually fail and potentially fix worst offenders.

Test Plan: unit tests

Reviewed By: stepan@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1838405

Signature: t1:1838405:1424478983:94cda86ed57f38b0cf626b74804fbc168d182c66

Summary:
Add option to disable time measurement in EventBase::loopBody()
to improve performances when time measurement is not used.

Test Plan:
Unit tests, benchmarking and manual tests.

Reviewed By: pavlo@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1846020

Tasks: 6086197

Signature: t1:1846020:1424459703:9686a84027e1137ee43eb0458b0baa4fee3a8abf

Summary:
This 'moves' bistro::AutoTimer into folly. I actually changed it a bit, so I'm
not migrating any existing uses in this diff, but I can do that as a followup.
We're using it in various places now, so it doesn't make sense to have it in
bistro.

Basically this class lets you conveniently time a series of things while
printing log messages, e.g.:
{
AutoTimer t("Done");
processA();
t.log("processA() complete");
}

would print
"processA() complete in XXX seconds"
"Done in YYY seconds"

I changed some things from bistro::AutoTimer:
- Use std::chrono::time_point<Clock> to store the start time.
- I removed the gflags. It seems weird to rely on those to control the timer,
since they would affect all uses of this. If a specific user of the timer
wants to actually control timing at runtime, I think it's better to use a
custom logger.
- I removed the 'min log duration'. As implemented it actually made the
constructor conflict: AutoTimer("foo", 1.2) is ambiguous. Also, it should
probably be set on the logger, so this likewise feels like a place where you
could make a custom logger.

I'm not sure that the way I use the default logger as a template argument is
best, so please suggest improvements to that.

Test Plan: unit test

Reviewed By: lesha@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1860794

Signature: t1:1860794:1424458219:a2dd0d428aedf063a888b2937b1443c7142554e8

Summary: I thought this was a race, but I think now it was something to do with using a value that had been moved out or something. Anyway, this refactor is cleaner and consolidates a few methods so it's all kinds of fuzzy feelings.

Test Plan: unit tests

Reviewed By: hannesr@fb.com

Subscribers: exa, folly-diffs@, yfeldblum, jsedgwick

FB internal diff: D1861376

Tasks: 6298004

Signature: t1:1861376:1424465861:736353ab3174656fec9e036e0ebd964970da38d0

Summary:
a couple of files were catching this exception and included the .cpp file :O. So we moved
to .h before realizing this was not intended to be caught. reverting the move to .h. codemod will follow.

Test Plan: fbmake -r folly && fbmake && fbmake runtests

Reviewed By: delong.j@fb.com

Subscribers: trunkagent, doug, seanc, folly-diffs@, yfeldblum

FB internal diff: D1854301

Tasks: 6245781

Signature: t1:1854301:1424375745:7e226196315fac99835752896cc5e549e91df2da

Summary:
Instead of returning a deactivated future, have `via` just set the executor. Propagate the executor from `then`. This fixes the `via().get()` problem, and has semantics similar to before for `via().then().then()`.

However, the semantics are now slightly different - each `then` goes back through the executor. This adds some overhead and tweaks the semantics (e.g. if the executor is a threadpool it might execute subsequent `then`s in another thread). However, with `futures::chain` recently introduced, and any other convenience methods that you can dream up and make a case for, we can reasonably get the old once-through-the-executor behavior when performance or other concerns demand it. e.g. `via().then(futures::chain(a, b, c))`.

Test Plan: unit tests

Reviewed By: hannesr@fb.com

Subscribers: zeus-diffs@, mmandal, steveo, rituraj, trunkagent, exa, folly-diffs@, yfeldblum, jsedgwick, davejwatson

FB internal diff: D1839691

Tasks: 6048744

Signature: t1:1839691:1424397180:ca0b0ea7b3867769ab8abd254a510059df67011e

Summary:
This reverts commit 1e407b48d379a41f32e7a980285dbdf4dadb2e33.

Test Plan: revert-hammer

Reviewed By: yitingli@fb.com

Subscribers: folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1858994

Signature: t1:1858994:1424386588:5c4608ecbe1f9ab1108ac12e506b157b54d0078b

Summary:
These were doing more assignments than necessary.
1) We don't need to set `core_` to `nullptr` and then immediately
overwrite it with `other.core_`.
2) Don't need to swap the booleans (this was actually an unitialized
memory access).

Test Plan: Ran all the tests.

Reviewed By: hans@fb.com

Subscribers: trunkagent, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1852386

Signature: t1:1852386:1424375154:25997209e76ccd16169125597e868932a5143ffb

Summary: This diff should let us include folly/io:compression into iOS and Android projects without pulling in a lot of dependencies and should allow the use of zlib.

Test Plan: fbconfig -r folly/io/tests && fbmake runtests

Reviewed By: seanc@fb.com

Subscribers: trunkagent, bmatheny, folly-diffs@, yfeldblum, seanc, benyluo

FB internal diff: D1853058

Tasks: 6245912

Signature: t1:1853058:1424370881:2ea243d93e6041502e5e356fa430c2483f652b40

Summary:
Use server bootstrap.

* code reuse
* Allows multiple accept threads easily.

Accept now doesn't happen in the server's eventBase, but a new thread.

I think I hit all the corner cases involving existingSocket, duplex, stopListening(), etc.

There are a lot of minor changes here to support all the cases, let me know if I should split anything to separate diffs

Test Plan: fbconfig -r thrift/lib/cpp2; fbmake runtests

Reviewed By: hans@fb.com

Subscribers: haijunz, yfeldblum, ruibalp, fbcode-common-diffs@, davejwatson, jsedgwick, trunkagent, doug, alandau, bmatheny, mshneer, folly-diffs@, mcduff, andrewcox, fugalh

FB internal diff: D1732895

Tasks: 5788102

Signature: t1:1732895:1423087631:379bbb131c35ce2221801bc7cec226f87ba0b1d9

Summary: from discussion

Test Plan: unit tests

Reviewed By: hans@fb.com

Subscribers: doug, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1829282

Signature: t1:1829282:1423180907:3630dac1378750b05f316c672fbbd71138d2bc0a

Summary: They are functionaly equivalent, no need to have more than one

Test Plan: fbconfig -r realtime/voip; fbmake runtests

Reviewed By: naizhi@fb.com

Subscribers: trunkagent, doug, ps, bmatheny, folly-diffs@, yfeldblum

FB internal diff: D1828044

Tasks: 6154007

Signature: t1:1828044:1423165354:f71d2fd28ca76a8f67a597c747f8578d2909823c

Summary: After D1827390 regular get and get_weak is comparable to Meyers and static singletons, so there's no need to keey _fast APIs.

Test Plan: benchmark && fbmake

Reviewed By: mshneer@fb.com

Subscribers: trunkagent, configerator-diffs@, fbcode-common-diffs@, mcduff, hitesh, mshneer, fugalh, acampi, alikhtarov, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1843219

Signature: t1:1843219:1424216566:f2f182a1c86bb5f0fb1f978d8c6b7a4388198f5f

Summary: This are the open-source-related additions. A separate diff will replace the current implementation in common/concurrency/ to use this one.

Test Plan: fbmake runtests

Reviewed By: simpkins@fb.com

Subscribers: trunkagent, net-systems@, folly-diffs@, yfeldblum

FB internal diff: D1845525

Signature: t1:1845525:1424207291:d30e3c5e85222527c2aff39c1250aa1e41b9a2cf

Summary:
The continuation at the end of the line with the while
was causing gcc to complain about it because it's a
single line comment.

Reformat it into a multiline comment and wrap it to 80 chars.

Test Plan: It's just a comment...

Reviewed By: paulbiss@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1850876

Signature: t1:1850876:1424124973:b2afbc2a8177ac6d11a21bf5a52093bcfd9cbb3e

Summary: I think this makes sense, especially if `interrupt_` is really rare.

Test Plan:
============================================================================
folly/futures/test/Benchmark.cpp                relative  time/iter  iters/s
============================================================================
constantFuture                                             101.25ns    9.88M
promiseAndFuture                                  92.86%   109.03ns    9.17M
withThen                                          28.96%   349.65ns    2.86M
----------------------------------------------------------------------------
oneThen                                                    337.33ns    2.96M
twoThens                                          58.46%   577.06ns    1.73M
fourThens                                         32.42%     1.04us  961.23K
hundredThens                                       1.45%    23.24us   43.04K
----------------------------------------------------------------------------
no_contention                                                4.45ms   224.48
contention                                        72.89%     6.11ms   163.61
----------------------------------------------------------------------------
throwAndCatch                                                6.34us  157.77K
throwAndCatchWrapped                              95.65%     6.63us  150.91K
throwWrappedAndCatch                             142.58%     4.45us  224.95K
throwWrappedAndCatchWrapped                      488.86%     1.30us  771.27K
----------------------------------------------------------------------------
throwAndCatchContended                                        1.01s  987.01m
throwAndCatchWrappedContended                    100.03%      1.01s  987.27m
throwWrappedAndCatchContended                    148.37%   682.86ms     1.46
throwWrappedAndCatchWrappedContended            18765.19%     5.40ms   185.21
============================================================================

Compare to D1843129#31 (seems to be an improvement?)

Reviewed By: hans@fb.com

Subscribers: trunkagent, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1847843

Signature: t1:1847843:1423855151:3602d49df245eda3f85325ab5efd63514213ca44

Summary:
Disable the -Wunevaluated-expression warning for this test:

EXPECT_EQ(typeid(ie), typeid(IntException));

Otherwise, clang warns about the unevaluated expression because
the expansion of EXPECT_EQ applies sizeof to an expression
with side effects:

folly/test/ExceptionWrapperTest.cpp:179:122: error: expression with side effects has no effect in an unevaluated context [-Werror,-Wunevaluated-expression]
switch (0) case 0: default: if (const ::testing::AssertionResult gtest_ar = (::testing::internal:: EqHelper<(sizeof(::testing::internal::IsNullLiteralHelper(typeid(ie))) == 1)>::Compare("typeid(ie)", "typeid(IntException)", typeid(ie), typeid(IntException)))) ; else ::testing::internal::AssertHelper(::testing::TestPartResult::kNonFatalFailure, "folly/test/ExceptionWrapperTest.cpp", 179, gtest_ar.failure_message()) = ::testing::Message();

Test Plan:
Ensure this compiles with clang-3.4, 3.5 and clang:dev.
I.e., ensure that this prints PASS at the end.

for i in '' 3.5 dev; do
test -n "$i" && i=--with-project-version=clang:$i
fbconfig -r --clang $i folly/test:exception_wrapper_test && fbmake dbgo
done && echo PASS

Reviewed By: mpawlowski@fb.com

Subscribers: mathieubaudet, folly-diffs@, yfeldblum

FB internal diff: D1850778

Tasks: 6244745

Signature: t1:1850778:1424111029:136478e9a3cc3a219047547d501de4c579a1a181

Summary:
* folly/wangle/channel/test/MockChannelHandler.h:
Avoiding a new warning that rendered this file uncompilable
by clang-3.5 and older.  Add cpp conditionals to protect
against that.

Test Plan:
Ensure it works with clang-3.4, 3.5 and clang:dev.
I.e., ensure that this prints PASS at the end.

for i in '' 3.5 dev; do
test -n "$i" && i=--with-project-version=clang:$i
fbconfig -r --clang $i folly/wangle/channel/test && fbmake runtests_dbgo
done && echo PASS

Reviewed By: meyering@fb.com

Subscribers: mpawlowski, fugalh, mathieubaudet, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1849474

Tasks: 6244745

Blame Revision: D1848330
@build-break

Summary:
Clang's new -Wself-move warning dings this code:

b = std::move(b);

But in this case, that is a deliberate test of
this capability, so we suppress that particular
warning for the duration of this small test function.

Test Plan:
Run this and note that it now compiles: (it passes the tests, too)
fbconfig --clang --with-project-version=clang:dev -r folly/test:optional_test && fbmake dbgo

Reviewed By: watashi@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1849689

Tasks: 6244745

Signature: t1:1849689:1423877932:4f479d682bd8ba97dcabed7fc29ce0a22c013969

@build-break (using this to work around bogus push failure: https://phabricator.fb.com/P19730606)

Summary:
* folly/ExceptionWrapper.h (class_name): Clang is not yet smart enough to
see that there is no harm in dereferencing an "item_" that we've just
verified is non-NULL.  Accommodate it, to avoid this:
./folly/ExceptionWrapper.h:199:30: error: expression with side effects will be evaluated despite being used as an operand to 'typeid' [-Werror,-Wpotentially-evaluated-expression]
return demangle(typeid(*item_));
^

Test Plan:
Run these commands and note there are fewer errors than before:
fbconfig --clang --with-project-version=clang:dev -r folly && fbmake dbgo

Reviewed By: mhorowitz@fb.com

Subscribers: trunkagent, yfeldblum, folly-diffs@

FB internal diff: D1848327

Tasks: 6244745

Signature: t1:1848327:1423869597:a58c9e9e3671befb78ae07fbd274a13d08ffb2a7

Blame Revision:

Summary: [Folly] clang:dev rejects vector<atomic<T>> in EventBaseTest.cpp.

Test Plan: Build and run `folly/io/async/test/EventBaseTest.cpp` using the current `clang`; try building with `clang:dev` and verifying that at least the related failures are gone.

Reviewed By: meyering@fb.com

Subscribers: mathieubaudet, folly-diffs@, yfeldblum, dougw, brettp

FB internal diff: D1848749

Tasks: 6244720

Signature: t1:1848749:1423866420:7b7354d4568b6a6d6a824236ae8d271f6855d90b

Summary:
This avoids warnings about e.g., sizeof(k++) that result
from macro expansion.
* folly/futures/test/ExecutorTest.cpp: Move increment out
of macro argument list.
* folly/test/FBVectorTestBenchmarks.cpp.h: Likewise.
* folly/test/LazyTest.cpp: Likewise.
Otherwise, we'd get errors like this:

folly/test/LazyTest.cpp:49:118: error: expression with side effects has no effect in an unevaluated context [-Werror,-Wunevaluated-expression]
switch (0) case 0: default: if (const ::testing::AssertionResult gtest_ar = (::testing::internal:: EqHelper<(sizeof(::testing::internal::IsNullLiteralHelper(++globalCount())) == 1)>::Compare("++globalCount()", "1", ++globalCount(), 1))) ; else ::testing::internal::AssertHelper(::testing::TestPartResult::kNonFatalFailure, "folly/test/LazyTest.cpp", 49, gtest_ar.failure_message()) = ::testing::Message();
^

Test Plan:
Run these commands and note there are fewer errors than before:
fbconfig --clang --with-project-version=clang:dev -r folly && fbmake dbgo

Reviewed By: njormrod@fb.com

Subscribers: folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1848324

Tasks: 6244745

Signature: t1:1848324:1423860890:bce44c5e0895804a21957893ae6b78e76dfbc4d3

Summary:
Upgrading to clang:dev (clang >3.6) brought in some new warnings.
This change address all of the issues exposed by the new
-Winconsistent-missing-override, usually by simply adding the
missing "override" keyword.  However, in
folly/wangle/channel/test/MockChannelHandler.h, I chose
to ignore those warnings for the mocked functions.
* folly/futures/test/ViaTest.cpp: Add missing "override"(s).
* folly/io/async/AsyncSSLSocket.h: Likewise.
* folly/io/async/AsyncSocket.h: Likewise.
* folly/io/async/EventBase.h: Likewise.
* folly/test/ExceptionWrapperTest.cpp: Likewise.
* folly/wangle/channel/AsyncSocketHandler.h: Likewise.
* folly/wangle/channel/test/MockChannelHandler.h: Ignore
the new warning for these functions.

Test Plan:
Run these commands and note there are fewer errors than before:
fbconfig --clang --with-project-version=clang:dev -r folly && fbmake dbgo

Reviewed By: hans@fb.com

Subscribers: trunkagent, fugalh, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1848330

Tasks: 6244745

Signature: t1:1848330:1423858909:b167ca220d6c9fe036d3adca08cf3053a7a9de16

Summary:
This seems cleaner. I also moved a Core member around and changed state to be a smaller size to save us 16 bytes. Might be neat to try to get this down to 128?

Fixed compilation with GCC 4.9, too.

Test Plan: Ran all the tests. Will also benchmark.

Reviewed By: hans@fb.com

Subscribers: trunkagent, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1843129

Signature: t1:1843129:1423789502:60e56d1af553994991195fcc350d37d644a556ca

Summary:
Pass TransportInfo object through connection setup.  This allows us to
pass along additional info from the setup if necessary.

Test Plan:
Run proxygen on my devserver listening on ipv4 and ipv6 for ports 80 and 443.
Configure it to run a lua request rule with the following lines:

io.stderr:write("jonlog: proxy " .. conn:getClientAddrOriginal() .. "\n")
io.stderr:write("jonlog: client " .. request:getClientIPStr() .. "\n")

Run haproxy also on my devserver, listening on ports 8555-8558, with each
forwarding to one of the four pairs (ipv4-localhost/ipv6-localhost, 80/443)

From my laptop, run curls against each of these four endpoints and make
sure that we print out "127.0.0.1" as the proxy IP, and my laptop's IP
as the client IP.

Reviewed By: cgheorghe@fb.com

Subscribers: jsedgwick, yfeldblum, trunkagent, ruibalp, bmatheny, folly-diffs@, dsp, nbm

FB internal diff: D1746590

Tasks: 5688127

Signature: t1:1746590:1423695880:f647964d95636a69a00304e144aef71ee0213d28

Summary:
`EliasFanoReader::position()` used to return `size() - 1` both when
the reader is positioned on the last element, and after `next()` is
called after that (and it return `false`). Now in the latter case
`position()` returns `size()` (consistently with the usual behaviour
of past-the-end iterators).

Also fix the return type of `jumpTo`.

Test Plan:
fbconfig folly/experimental/test:eliasfano_test && fbmake runtests_opt

Reviewed By: philipp@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1846275

Signature: t1:1846275:1423790264:151f5d2e1e09d4e24dfb758473dfb9cd52c070bd

Summary:
A colleague at another company started making fun of
MicroSpinLock for its x86 assembly and ad hoc compiler memory
barriers. Use C++11 (which wasn't really a thing at the time I wrote
this).

Test Plan: folly's runtests. What else would we like?

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1841563

Signature: t1:1841563:1423780458:a447c081fbd72e3420b23e95dcf26575c9a06798

Summary:
Short skips have been optimized by adding special cases that use simple iteration when it is convenient. Large skips have been optimized by using the broadword selection algorithm by Vigna (improved with ideas by Gog&Petri) instead of iterating on the zeros/ones of the upper bits.

The benchmarks had to be made more granular to measure the differences, in particular they used to test skipping with a fixed skip length for each test, while now we average over a range of skips to better simulate a random distribution.

The improvements are very significant for `skipTo()` on short skips, about 2-3x for skips at distance 1 or 2, which can occur when intersecting dense lists. On large skips the gain is about 17%.

`skip()` exhibits slightly smaller improvements.

before               after
============================================================================  ==================
folly/experimental/test/EliasFanoCodingTest.cpp relative  time/iter  iters/s  time/iter  iters/s
============================================================================  ==================
Next                                                         2.52ns  396.26M     2.52ns  397.28M
Skip_ForwardQ128(1)                                          8.66ns  115.52M     3.92ns  255.28M
Skip_ForwardQ128(2)                                          8.37ns  119.42M     5.08ns  197.04M
Skip_ForwardQ128(4_pm_1)                                     9.67ns  103.41M     7.04ns  142.02M
Skip_ForwardQ128(16_pm_4)                                   21.44ns   46.65M    19.68ns   50.82M
Skip_ForwardQ128(64_pm_16)                                  30.86ns   32.40M    27.58ns   36.26M
Skip_ForwardQ128(256_pm_64)                                 37.80ns   26.45M    32.49ns   30.78M
Skip_ForwardQ128(1024_pm_256)                               38.99ns   25.65M    33.39ns   29.95M
Jump_ForwardQ128                                            37.91ns   26.37M    34.05ns   29.37M
----------------------------------------------------------------------------  ------------------
SkipTo_SkipQ128(1)                                          13.87ns   72.10M     4.42ns  226.49M
SkipTo_SkipQ128(2)                                          18.80ns   53.20M     8.58ns  116.55M
SkipTo_SkipQ128(4_pm_1)                                     23.59ns   42.38M    11.43ns   87.50M
SkipTo_SkipQ128(16_pm_4)                                    36.04ns   27.74M    31.19ns   32.06M
SkipTo_SkipQ128(64_pm_16)                                   53.34ns   18.75M    43.88ns   22.79M
SkipTo_SkipQ128(256_pm_64)                                  62.27ns   16.06M    49.08ns   20.37M
SkipTo_SkipQ128(1024_pm_256)                                65.63ns   15.24M    52.24ns   19.14M
JumpTo_SkipQ128                                             65.89ns   15.18M    54.61ns   18.31M
----------------------------------------------------------------------------  ------------------
Encode_10                                                  111.94ns    8.93M   117.24ns    8.53M
Encode                                                       5.35ms   187.02     5.64ms   177.15
----------------------------------------------------------------------------  ------------------
Select64                                                     8.07ns  123.96M     8.04ns  124.35M
============================================================================  ==================

Test Plan:
fbconfig folly/experimental/test:eliasfano_test && fbmake runtests_opt

Reviewed By: philipp@fb.com

Subscribers: yfeldblum, fbcode-common-diffs@, chaoyc, search-fbcode-diffs@, unicorn-diffs@, trunkagent, folly-diffs@

FB internal diff: D1793554

Signature: t1:1793554:1423619344:1b078c0789639f317342ebcc77b11fe91859cd7b

Summary: Saw this while debugging some stuff. Just an oversight, right?

Test Plan: Ran all the tests.

Reviewed By: hans@fb.com

Subscribers: folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1843016

Signature: t1:1843016:1423704557:d9fdb4b879ab4fcfda54a5fcb16a639df15872b5

Summary: That is, for all inputs except r-values. Now with support for GCC.

Test Plan: Run tests

Reviewed By: ajaymenon@fb.com

Subscribers: moharrami, trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1822339

Signature: t1:1822339:1423683482:027871549d69017a7a23a675025851a0b876ad77

Summary:
This was recently added by @andrii to provide stack traces,
but it no longer needed since he now produces them from a hook in
folly/experimental/SingletonStackTrace.cpp

Test Plan: Continues to build without the include.

Reviewed By: andrii@fb.com

Subscribers: folly-diffs@, yfeldblum, andrii

FB internal diff: D1842654

Signature: t1:1842654:1423696133:cfa91851f28696082f790eb13c3b0b015c813590

Summary:
This reverts commit 4ebb2303bbcf343d7c2bcc95d55557c0a3b444f3.
The caching mechanism was based on a misunderstanding of the
implementation of CLOCK_MONOTONIC_COARSE, and is not correct.
On the plus side, the upstream kernel patch

e76b027e6408 x86,vdso: Use LSL unconditionally for vgetcpu

gets the vdso getcpu from 16 nanos down to 10 (half of which is the
inherent indirect call).

Test Plan: unit tests

Reviewed By: delong.j@fb.com

Subscribers: trunkagent, bmaurer, tudorb, folly-diffs@, yfeldblum, jdelong

FB internal diff: D1840690

Signature: t1:1840690:1423693026:33801341ec0b83bf47e050be6528c5dd05021ed5

Summary: Open-source build was broken because Symbolizer is not part of it.

Test Plan: singleton unit test w/ and w/o SingletonStackTrace.cpp linked in.

Reviewed By: alikhtarov@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1840346

Signature: t1:1840346:1423690004:926c2aa21e0b7916260749120997ad56fab6f742

Summary: This is usually available on linux

Test Plan: Existing tests and manual test on arclinux

Reviewed By: mpawlowski@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1840081

Signature: t1:1840081:1423619986:911c95f9f04f286e9f113543ab4b705cf1b17396

Summary: removing // as it could break some comment parser

Test Plan: unitz

Reviewed By: dancol@fb.com

Subscribers: trunkagent, doug, seanc, folly-diffs@, yfeldblum

FB internal diff: D1830591

Signature: t1:1830591:1423203436:9e8b28b714eb2dc080462ab3e8ce04c176df8586

Summary:
I have half a mind to just rip this out and let people use std::bind if they need this. But I won't be so cruel.

Why isn't this just implemented as `then(std::bind(method, object))` anyway? Is the template soup we have now faster?

Test Plan:
Fixed the unit tests to use the new format.
Will look to contbuild to catch all the things this might break (if anyone is using it at all?), and will fix them.

Reviewed By: hannesr@fb.com

Subscribers: trunkagent, exa, folly-diffs@, yfeldblum, jsedgwick, davejwatson

FB internal diff: D1831118

Signature: t1:1831118:1423243771:65db9a89daf14d8bd88331c503ba1ea7ab03b679

Summary:
`futures::chain<A,Z>(a, b, c, d, e, f, ..., z)` where `a` is a callback suitable for `Future<A>::then` and `z` is a callback suitable for `Future<Y>::then<Z>`.

This will be important, at least in the background, for the new `via`. It will probably also be useful to some user sometime.

I imagine this will be tweaked over time if people find magic ways to get it to deduce the types better. But this works and it's not *too* much trouble to specify A and Z.

Test Plan: unit

Reviewed By: davejwatson@fb.com

Subscribers: trunkagent, exa, folly-diffs@, yfeldblum, jsedgwick

FB internal diff: D1831073

Tasks: 6048744

Signature: t1:1831073:1423259292:711be0e047a2acb706fd74e529d5d5fb6abda566