Reland "Get rid of tail padding within `absl::Duration`. This reduces memory usage needs when storing duration in containers (e.g. `vector<absl::Duration>` uses 25% less memory), and allows classes with `absl::Duration` fields to fit other stuff in memory previously used by tail padding (e.g. `std::optional<absl::Duration>` is now 16 bytes instead of 24)."

PiperOrigin-RevId: 524256689
Change-Id: Ibf40d9e5411020179fa34c972349c7b58aa9d908

PiperOrigin-RevId: 524112966
Change-Id: I197f98f95b1c4de7f53295a6a01db9b0379b4f55

tests under sanitizers. The overrides break the sanitizers.

PiperOrigin-RevId: 524037272
Change-Id: I85b87d3870c488cb316505e94b394c6f98e9f60f

for relative timeouts

PiperOrigin-RevId: 523789416
Change-Id: Ide4cfdcae9ea7bffca3355c80ea9c8833a9536e6

PiperOrigin-RevId: 523745259
Change-Id: Ia2be4ee672a4c1b72c6ecc035ed9c2e401b56d1e

In debug mode, detect cases of btree comparators that violate transitivity, i.e. comp(A,B) && comp(B,C) -> comp(A,C).

When inserting a new element, we verify that the key is ordered correctly with respect to all the other values on the node, which can be done in constant time.

PiperOrigin-RevId: 523729309
Change-Id: Idb5a5912a9aa5411d086cb9fa76791523046778a

std::is_trivially_copyable

PiperOrigin-RevId: 523724345
Change-Id: Id68c79c3bbb253d892bdef4659ac8a926e023d12

Use Linux's prctl(PR_SET_VMA) system call to name memory arenas being
allocated using mmap(MAP_ANONYMOUS).

This change allows Abseil's memory arena(s) to be distinguished from
other uses of anonymous memory within a process, which in turn helps
investigations into the memory usage of applications.

The change adds a new prctl() system call to the code paths that call
mmap(). This is not expected to add significant overhead to applications.

The call to prctl(PR_SET_VMA, ...) can fail if the Linux kernel in use was
not configured with the CONFIG_ANON_VMA_NAME kernel option.  This should
be OK since the naming memory regions is primarily a debugging aid.

PiperOrigin-RevId: 523687348
Change-Id: Ie404e5eeef0a6da53330b3a56149c4f3bc6bf5c7

This has nothing to do with copy assignment or with destruction.

PiperOrigin-RevId: 523576913
Change-Id: Iddb6ab73bcfd8b01a29880cdf4db4bc2b5aead8a

This has nothing to do with copy construction or copy assignment.

PiperOrigin-RevId: 523571907
Change-Id: I338b5a40616594406ca8c80b747540c8935798e9

This has nothing to do with copy construction or copy assignment.

PiperOrigin-RevId: 523557887
Change-Id: I332d6ceaf738305157605f1271cb577a83d198c5

Don't require a trivial move constructor and trivial destructor. This excludes
types that have declared themselves trivially relocatable by another means, like
std::unique_ptr. Instead use "is trivially relocatable" directly, which includes
all previous types as well as those that have opted in.
PiperOrigin-RevId: 523557136
Change-Id: Icea2dbb8f36f99623308155f2e5b1edd8e5bd36b

PiperOrigin-RevId: 523220096
Change-Id: Iaffea2c9c4d112839ca8c2c7f130f72c3d7cc35b

This is to highlight contributing guidelines and in particular call
out that Googlers must send us Piper CLs.

PiperOrigin-RevId: 523127713
Change-Id: I38e219d811adc5f14c7aeaa952d5f25de75198f5

proposed standard pthread_cond_clockwait() and sem_clockwait().
These are currently implemented in glibc >= 2.30.

These methods take a clock and use an absolute time with reference
to that clock, so KernelTimeout now can produce these values.

PiperOrigin-RevId: 522824226
Change-Id: Ife98713f6f95d800b1f8e52d5364a3dbebc4f8a6

PiperOrigin-RevId: 522411202
Change-Id: Ifc99f5f6a227efd697039344ea75f53c6f282e53

PiperOrigin-RevId: 522393331
Change-Id: Ia5f4ad6a2d16c033ea97f3c7e27e8eb7ee429242

PiperOrigin-RevId: 522392902
Change-Id: I5764edbe85612e90d02caae49bbf629dcb8879e3

using the non-portable pthread_cond_timedwait_relative_np()

PiperOrigin-RevId: 522340555
Change-Id: I08682f74d8d94965330f12274c7a92632b1a29f1

PiperOrigin-RevId: 521932692
Change-Id: If637de6501a4ac41f0078d581049d23aad3480a4

https://github.com/google/oss-policies-info/blob/main/foundational-cxx-support-matrix.md

PiperOrigin-RevId: 521573177
Change-Id: I1f12ddbd8516314ee2ed7f8ba6a6895b03c6c270

PiperOrigin-RevId: 521556211
Change-Id: I1e1812eb11bfc5772abbf38ce348580c3afa5612

were broken on MSVC 2017, but MSVC 2017 is no longer supported

PiperOrigin-RevId: 521527454
Change-Id: I7203708bdc9aa03c9764c9c36db7ce5777e43c3c

PiperOrigin-RevId: 521525676
Change-Id: I40083f534c6904b4823138666deac18ffe6deab6

PiperOrigin-RevId: 521450545
Change-Id: Ia4fe02a57d23411f0a80443c0ad89dfaf4117a37

PiperOrigin-RevId: 521133781
Change-Id: I1334ea683bc01ef9b1b9800d6681e29dd2a1ec55

We know that the elements are trivially destructible if this path is used, so
there is no need to call their destructors one by one.

PiperOrigin-RevId: 521088624
Change-Id: I3edff97a073770f99031eefa7a34968fad5d7880

The fact that this is called from paths where the element type may not have a
trivial destructor is preventing an optimization (see the TODO). Stop calling
from those paths so that the optimization can be made in an upcoming CL.

PiperOrigin-RevId: 521087730
Change-Id: Id2b66d8f36bb0d294784d0793fdd8f07e315739f

The copy constructor isn't doing or simulating copy assignment; nor is it
destroying anything. We don't need to require that those operations be trivial.

PiperOrigin-RevId: 521020499
Change-Id: I0f36a720384b333ea15e6c8275872fd4fd9a738f

PiperOrigin-RevId: 520955097
Change-Id: I50a19305aed2b60dea0293b1a2106673e4cb7756

PiperOrigin-RevId: 520925224
Change-Id: I8b7eb8b4d4b99d72b860aec532516b428fb2be23

PiperOrigin-RevId: 520724148
Change-Id: Ia90c4a711649e89454bc2ca0a9d0d771d56e79c0

This change fixes -Wimplicit-const-int-float-conversion warnings
by making the conversions explicit.

PiperOrigin-RevId: 520707623
Change-Id: Ib6917469120cd7458257195cbf39beb3fd397543

For function N in the stack, the current code reports the size of
frame N - 1. Fix that.

PiperOrigin-RevId: 520688072
Change-Id: I984729f72f79aebae1b6997cb51d3ddef9199d1e

These have nothing to do with copy construction or copy assignment, and using
"is trivially copy constructible" can in theory even give the wrong result if
the copy constructor is trivial but the move constructor is not.

PiperOrigin-RevId: 520488816
Change-Id: I6da4d57f3ce23b03044e0bf9aa70a14b51651fa3

PiperOrigin-RevId: 520197681
Change-Id: I96d0253b61bb683bf30060a9b4c19e2c9dce629b

PiperOrigin-RevId: 519939158
Change-Id: I9b049fa55167ed4064f3909887eec7bc52601677

It currently gives the wrong result for types with a user-provided destructor:

    struct S {
      ~S();
    };

    static_assert(!__is_trivially_relocatable(S));

PiperOrigin-RevId: 519855600
Change-Id: I5f0659ad0831974805a5ed4b615e3b6250d23154

There's no reason to require the type to be trivially
copy-constructible/assignable in order to avoid running destructors—those
traits have nothing to do with destruction.

PiperOrigin-RevId: 519822201
Change-Id: I2ed7bbb53f0c1a512017115ff29fb27a24c6b11a

absl int128: avoid shifting signed integer by a number of bits greater than or equal to the precision of the operand

PiperOrigin-RevId: 519808237
Change-Id: I9123b167b606d609b8f3924d6f4fd298fa866a90