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

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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

5 files changed, 22 insertions, 17 deletions

diff --git a/absl/container/internal/hashtablez_sampler.cc b/absl/container/internal/hashtablez_sampler.cc
index 0a7ef61c..4aec0a07 100644
--- a/absl/container/internal/hashtablez_sampler.cc
+++ b/absl/container/internal/hashtablez_sampler.cc
@@ -38,16 +38,18 @@ ABSL_CONST_INIT std::atomic<bool> g_hashtablez_enabled{
 ABSL_CONST_INIT std::atomic<int32_t> g_hashtablez_sample_parameter{1 << 10};
 ABSL_CONST_INIT std::atomic<int32_t> g_hashtablez_max_samples{1 << 20};
 
-#if ABSL_HAVE_THREAD_LOCAL
-thread_local absl::base_internal::ExponentialBiased
-    g_exponential_biased_generator;
-#else
-ABSL_CONST_INIT static absl::base_internal::ExponentialBiased
+#if ABSL_PER_THREAD_TLS == 1
+ABSL_PER_THREAD_TLS_KEYWORD absl::base_internal::ExponentialBiased
     g_exponential_biased_generator;
 #endif
 
 }  // namespace
 
+#if ABSL_PER_THREAD_TLS == 1
+ABSL_PER_THREAD_TLS_KEYWORD int64_t global_next_sample = 0;
+#endif  // ABSL_PER_THREAD_TLS == 1
+
+
 HashtablezSampler& HashtablezSampler::Global() {
   static auto* sampler = new HashtablezSampler();
   return *sampler;
@@ -189,6 +191,10 @@ HashtablezInfo* SampleSlow(int64_t* next_sample) {
     return HashtablezSampler::Global().Register();
   }
 
+#if ABSL_PER_THREAD_TLS == 0
+  *next_sample = std::numeric_limits<int64_t>::max();
+  return nullptr;
+#else
   bool first = *next_sample < 0;
   *next_sample = g_exponential_biased_generator.Get(
       g_hashtablez_sample_parameter.load(std::memory_order_relaxed));
@@ -210,12 +216,9 @@ HashtablezInfo* SampleSlow(int64_t* next_sample) {
   }
 
   return HashtablezSampler::Global().Register();
+#endif
 }
 
-#if ABSL_PER_THREAD_TLS == 1
-ABSL_PER_THREAD_TLS_KEYWORD int64_t global_next_sample = 0;
-#endif  // ABSL_PER_THREAD_TLS == 1
-
 void UnsampleSlow(HashtablezInfo* info) {
   HashtablezSampler::Global().Unregister(info);
 }
diff --git a/absl/container/internal/hashtablez_sampler.h b/absl/container/internal/hashtablez_sampler.h
index 53996bb9..c694df05 100644
--- a/absl/container/internal/hashtablez_sampler.h
+++ b/absl/container/internal/hashtablez_sampler.h
@@ -186,16 +186,14 @@ extern ABSL_PER_THREAD_TLS_KEYWORD int64_t global_next_sample;
 // Returns an RAII sampling handle that manages registration and unregistation
 // with the global sampler.
 inline HashtablezInfoHandle Sample() {
-#if ABSL_PER_THREAD_TLS == 0
-  static auto* mu = new absl::Mutex;
-  static int64_t global_next_sample = 0;
-  absl::MutexLock l(mu);
-#endif  // !ABSL_HAVE_THREAD_LOCAL
-
+#if ABSL_PER_THREAD_TLS == 1
   if (ABSL_PREDICT_TRUE(--global_next_sample > 0)) {
     return HashtablezInfoHandle(nullptr);
   }
   return HashtablezInfoHandle(SampleSlow(&global_next_sample));
+#else
+  return HashtablezInfoHandle(nullptr);
+#endif  // !ABSL_PER_THREAD_TLS
 }
 
 // Holds samples and their associated stack traces with a soft limit of
diff --git a/absl/container/internal/hashtablez_sampler_test.cc b/absl/container/internal/hashtablez_sampler_test.cc
index 7f9e8dd2..af4b5ee1 100644
--- a/absl/container/internal/hashtablez_sampler_test.cc
+++ b/absl/container/internal/hashtablez_sampler_test.cc
@@ -168,6 +168,7 @@ TEST(HashtablezInfoTest, RecordRehash) {
   EXPECT_EQ(info.num_erases.load(), 0);
 }
 
+#if ABSL_PER_THREAD_TLS == 1
 TEST(HashtablezSamplerTest, SmallSampleParameter) {
   SetHashtablezEnabled(true);
   SetHashtablezSampleParameter(100);
@@ -211,6 +212,7 @@ TEST(HashtablezSamplerTest, Sample) {
   }
   EXPECT_NEAR(sample_rate, 0.01, 0.005);
 }
+#endif
 
 TEST(HashtablezSamplerTest, Handle) {
   auto& sampler = HashtablezSampler::Global();
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index bf0c03c4..469226fe 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -638,8 +638,8 @@ class raw_hash_set {
     }
 
     friend bool operator==(const iterator& a, const iterator& b) {
-      /* To be enabled: a.assert_is_valid(); */
-      /* To be enabled: b.assert_is_valid(); */
+      a.assert_is_valid();
+      b.assert_is_valid();
       return a.ctrl_ == b.ctrl_;
     }
     friend bool operator!=(const iterator& a, const iterator& b) {
diff --git a/absl/container/internal/raw_hash_set_test.cc b/absl/container/internal/raw_hash_set_test.cc
index 33cfa72c..ec8f9231 100644
--- a/absl/container/internal/raw_hash_set_test.cc
+++ b/absl/container/internal/raw_hash_set_test.cc
@@ -1841,6 +1841,7 @@ TEST(TableDeathTest, EraseOfEndAsserts) {
   EXPECT_DEATH_IF_SUPPORTED(t.erase(t.end()), kDeathMsg);
 }
 
+#if ABSL_PER_THREAD_TLS == 1
 TEST(RawHashSamplerTest, Sample) {
   // Enable the feature even if the prod default is off.
   SetHashtablezEnabled(true);
@@ -1861,6 +1862,7 @@ TEST(RawHashSamplerTest, Sample) {
   EXPECT_NEAR((end_size - start_size) / static_cast<double>(tables.size()),
               0.01, 0.005);
 }
+#endif
 
 TEST(RawHashSamplerTest, DoNotSampleCustomAllocators) {
   // Enable the feature even if the prod default is off.