Export of internal Abseil changes

--
049ac45508e335c6f010f2d28d71016b9fa65b4e by Derek Mauro <dmauro@google.com>:

Fix librt detection

PiperOrigin-RevId: 280207723

--
6382c3a9fb2643af9dc031f92ca846c4a78e249c by Andy Getzendanner <durandal@google.com>:

Fix Conan builds

Import of https://github.com/abseil/abseil-cpp/pull/400

PiperOrigin-RevId: 280025424

--
aebcd52b1686ac82663a8d0193b60d0122a43372 by Samuel Benzaquen <sbenza@google.com>:

Enable the assertion in the iterator's operator== and operator!=

PiperOrigin-RevId: 279998951

--
5b61d909e2159ac6fd45e0e456818db1e725ecd1 by Derek Mauro <dmauro@google.com>:

Add best effort support for compiling much of Abseil with MinGW.
This involves disabling ABSL_ATTRIBUTE_WEAK and adding link flags.

A change to CCTZ is still necessary.

Tests were not run yet, but most of them now build.

PiperOrigin-RevId: 279966541

--
4336f8b10cff906e2defdd7d1d449cde4907da5d by Abseil Team <absl-team@google.com>:

Add comments and relax memory orders in base_internal::CallOnceImpl.

Add a comment to document the memory order guarantee if
base_internal::SpinLockWait() is called and returns kOnceDone.

Add a comment for the load/store sequence in base_internal::CallOnceImpl
based on Mike Burrows' explanation.

The atomic load of 'control' in the #ifndef NDEBUG block does not need
std::memory_order_acquire. It can use std::memory_order_relaxed.

The atomic compare_exchange_strong of 'control' does not need
std::memory_order_acquire in the success case. It can use
std::memory_order_relaxed.
PiperOrigin-RevId: 279814155

--
407de3a5e9af957cded54a136ca0468bde620d4d by Abseil Team <absl-team@google.com>:

Added a script to generate abseil.podspec from all BUILD.bazel files automatically.

PiperOrigin-RevId: 279811441

--
26139497d4a363d6c7bc989c554da593e8819a07 by Derek Mauro <dmauro@google.com>:

Add missing copyright and Apache License to //absl/functional/BUILD.bazel

PiperOrigin-RevId: 279795227

--
98ed625b02af6e5834edf52a920d8ca2dab4cd90 by Matt Kulukundis <kfm@google.com>:

Switch the implementation of hashtablez to *only* work on platforms that have a
PER_THREAD_TLS.

The old case is very slow (global mutex) and nobody collects data from that
configuration anyway.

PiperOrigin-RevId: 279775149

--
07225900ef672c005c38f467ad3f92f38d0922b3 by Derek Mauro <dmauro@google.com>:

Remove the minumum glibc version check

PiperOrigin-RevId: 279750412

--
ec09956a951b4f52228ecc81968b8db7ae19ed15 by Derek Mauro <dmauro@google.com>:

CMake only: link with -lrt to support older glibc versions

PiperOrigin-RevId: 279741661

--
97b113fb2e8246f6152c36330ba13793b37154b6 by Xiaoyi Zhang <zhangxy@google.com>:

Internal change.

PiperOrigin-RevId: 279390188

--
ca8f72f2721546cc9b01bd01b2ea144962e6e0c5 by Andy Getzendanner <durandal@google.com>:

Expose PutTwoDigits for internal use within Abseil.

PiperOrigin-RevId: 279374239

--
14c6384cc03bbdfdefd2e4b635f104af5dd7e026 by Derek Mauro <dmauro@google.com>:

Remove log_severity sources from the base target.
They are already compiled as part of a separate library.

PiperOrigin-RevId: 279372619

--
3c5d926c718f8bf394e3bee87b6ba8d94601e0d3 by Abseil Team <absl-team@google.com>:

s/indepdent/independent/g in SimpleAtof's documentation.

PiperOrigin-RevId: 279350836

--
de2c44be8a8edf9efa1fe2007cba3564f3e5b0b8 by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 279346990

--
2ba078341423fcf6d0ba5ca1831f86570a26e615 by Samuel Benzaquen <sbenza@google.com>:

Add hash support for std::wstring, std::u16string and std::u32string.

PiperOrigin-RevId: 279320672

--
3272d3ffcfa55283a04f90e5868701912da95ef7 by Andy Soffer <asoffer@google.com>:

Removing a bunch of __restricts that amount to no performance differences. One
of these is the cause of https://github.com/abseil/abseil-cpp/issues/396. In
particular, in one of the Vector128Store functions, restricts on two pointers
that were indeed aliased seems to be the root cause of the issues.

Closes #396

PiperOrigin-RevId: 279318999

--
342f338ab31cc24344d5de8f28cf455bbb629a17 by Jorg Brown <jorg@google.com>:

Support uint128 in SimpleAtoi

PiperOrigin-RevId: 279234038

--
81cb0a04cf2dc4515d303679fc60968712191571 by Derek Mauro <dmauro@google.com>:

Change the check for futex availability to support older Linux systems

PiperOrigin-RevId: 279147079

--
cb4ca4aa4c8d2d710a5d483c56c4ce4f979e14b1 by Abseil Team <absl-team@google.com>:

Add IWYU pragma: export for int128 .inc files.

PiperOrigin-RevId: 279107098

--
b8df86ef610c366729f07326c726f3e34817b4dd by Abseil Team <absl-team@google.com>:

An optimization for Waiter::Post() in the SEM waiter mode.

Like the FUTEX waiter mode, Waiter::Post() only needs to call Poke() if
it incremented the atomic variable from 0.

PiperOrigin-RevId: 279086133
GitOrigin-RevId: 049ac45508e335c6f010f2d28d71016b9fa65b4e
Change-Id: I4c1a4073fff62cb6a1fcb1c104aa7d62dad588c2
This commit is contained in:
Abseil Team 2019-11-13 08:54:32 -08:00 committed by Andy Getz
parent 85092b4b64
commit fa8c75182f
26 changed files with 503 additions and 117 deletions

View file

@ -192,7 +192,9 @@ cc_library(
],
copts = ABSL_DEFAULT_COPTS,
linkopts = select({
"//absl:windows": [],
"//absl:windows": [
"-DEFAULTLIB:shlwapi.lib",
],
"//conditions:default": ["-pthread"],
}) + ABSL_DEFAULT_LINKOPTS,
deps = [

View file

@ -14,6 +14,8 @@
# limitations under the License.
#
find_library(LIBRT rt)
absl_cc_library(
NAME
atomic_hook
@ -163,16 +165,18 @@ absl_cc_library(
"internal/thread_identity.h"
"internal/tsan_mutex_interface.h"
"internal/unscaledcycleclock.h"
"log_severity.h"
SRCS
"internal/cycleclock.cc"
"internal/spinlock.cc"
"internal/sysinfo.cc"
"internal/thread_identity.cc"
"internal/unscaledcycleclock.cc"
"log_severity.cc"
COPTS
${ABSL_DEFAULT_COPTS}
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
$<$<BOOL:${LIBRT}>:${LIBRT}>
$<$<BOOL:${MINGW}>:"shlwapi">
DEPS
absl::atomic_hook
absl::base_internal

View file

@ -158,9 +158,11 @@
// Weak attributes currently do not work properly in LLVM's Windows backend,
// so disable them there. See https://bugs.llvm.org/show_bug.cgi?id=37598
// for further information.
#if (ABSL_HAVE_ATTRIBUTE(weak) || \
// The MinGW compiler doesn't complain about the weak attribute until the link
// step, presumably because Windows doesn't use ELF binaries.
#if (ABSL_HAVE_ATTRIBUTE(weak) || \
(defined(__GNUC__) && !defined(__clang__))) && \
!(defined(__llvm__) && defined(_WIN32))
!(defined(__llvm__) && defined(_WIN32)) && !defined(__MINGW32__)
#undef ABSL_ATTRIBUTE_WEAK
#define ABSL_ATTRIBUTE_WEAK __attribute__((weak))
#define ABSL_HAVE_ATTRIBUTE_WEAK 1

View file

@ -148,7 +148,7 @@ void CallOnceImpl(std::atomic<uint32_t>* control,
Args&&... args) {
#ifndef NDEBUG
{
uint32_t old_control = control->load(std::memory_order_acquire);
uint32_t old_control = control->load(std::memory_order_relaxed);
if (old_control != kOnceInit &&
old_control != kOnceRunning &&
old_control != kOnceWaiter &&
@ -166,14 +166,23 @@ void CallOnceImpl(std::atomic<uint32_t>* control,
// Must do this before potentially modifying control word's state.
base_internal::SchedulingHelper maybe_disable_scheduling(scheduling_mode);
// Short circuit the simplest case to avoid procedure call overhead.
// The base_internal::SpinLockWait() call returns either kOnceInit or
// kOnceDone. If it returns kOnceDone, it must have loaded the control word
// with std::memory_order_acquire and seen a value of kOnceDone.
uint32_t old_control = kOnceInit;
if (control->compare_exchange_strong(old_control, kOnceRunning,
std::memory_order_acquire,
std::memory_order_relaxed) ||
base_internal::SpinLockWait(control, ABSL_ARRAYSIZE(trans), trans,
scheduling_mode) == kOnceInit) {
base_internal::Invoke(std::forward<Callable>(fn),
std::forward<Args>(args)...);
// The call to SpinLockWake below is an optimization, because the waiter
// in SpinLockWait is waiting with a short timeout. The atomic load/store
// sequence is slightly faster than an atomic exchange:
// old_control = control->exchange(base_internal::kOnceDone,
// std::memory_order_release);
// We opt for a slightly faster case when there are no waiters, in spite
// of longer tail latency when there are waiters.
old_control = control->load(std::memory_order_relaxed);
control->store(base_internal::kOnceDone, std::memory_order_release);
if (old_control == base_internal::kOnceWaiter) {

View file

@ -82,16 +82,6 @@
// Standard Library Check
// -----------------------------------------------------------------------------
// We have chosen glibc 2.12 as the minimum as it was tagged for release
// in May, 2010 and includes some functionality used in Google software
// (for instance pthread_setname_np):
// https://sourceware.org/ml/libc-alpha/2010-05/msg00000.html
#if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
#if !__GLIBC_PREREQ(2, 12)
#error "Minimum required version of glibc is 2.12."
#endif
#endif
#if defined(_STLPORT_VERSION)
#error "STLPort is not supported."
#endif