Export of internal Abseil changes

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3e60f355db5afd7a864591d81a6c383b6c0a0780 by Samuel Benzaquen <sbenza@google.com>:

Internal change

PiperOrigin-RevId: 272531442

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6d189240b8cebe3a390c730de491156d03049229 by Andy Getzendanner <durandal@google.com>:

Fix AtomicHook init-order fiasco under MSVC 2019.

On this platform, constexpr static init sometimes happens after dynamic init =/.  When it does, we should not zero hook_ (overwriting the value written there by dynamic init); instead we should leave it alone.  This works even when constexpr static init goes first since all uses of AtomicHook should have static storage duration and be zero-initialized.

https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html

PiperOrigin-RevId: 272525226

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d01b14fc06bc75b41c51976ed32e7c304ea1aab7 by Abseil Team <absl-team@google.com>:

exclude emscripten from running tests involving long doubles

PiperOrigin-RevId: 272497628
GitOrigin-RevId: 3e60f355db5afd7a864591d81a6c383b6c0a0780
Change-Id: I3c8a8f5acaf7652a06ef40cf028ef5d2e142f81b

3 files changed, 23 insertions, 4 deletions

diff --git a/absl/container/internal/hashtablez_sampler.cc b/absl/container/internal/hashtablez_sampler.cc
index d03dd82..054e898 100644
--- a/absl/container/internal/hashtablez_sampler.cc
+++ b/absl/container/internal/hashtablez_sampler.cc
@@ -228,8 +228,26 @@ int64_t HashtablezSampler::Iterate(
   return dropped_samples_.load(std::memory_order_relaxed);
 }
 
+static bool ShouldForceSampling() {
+  enum ForceState {
+    kDontForce,
+    kForce,
+    kUninitialized
+  };
+  ABSL_CONST_INIT static std::atomic<ForceState> global_state{
+      kUninitialized};
+  ForceState state = global_state.load(std::memory_order_relaxed);
+  if (ABSL_PREDICT_TRUE(state == kDontForce)) return false;
+
+  if (state == kUninitialized) {
+    state = AbslContainerInternalSampleEverything() ? kForce : kDontForce;
+    global_state.store(state, std::memory_order_relaxed);
+  }
+  return state == kForce;
+}
+
 HashtablezInfo* SampleSlow(int64_t* next_sample) {
-  if (kAbslContainerInternalSampleEverything) {
+  if (ABSL_PREDICT_FALSE(ShouldForceSampling())) {
     *next_sample = 1;
     return HashtablezSampler::Global().Register();
   }
diff --git a/absl/container/internal/hashtablez_sampler.h b/absl/container/internal/hashtablez_sampler.h
index 4112175..53996bb 100644
--- a/absl/container/internal/hashtablez_sampler.h
+++ b/absl/container/internal/hashtablez_sampler.h
@@ -280,7 +280,7 @@ void SetHashtablezMaxSamples(int32_t max);
 // initialization of static storage duration objects.
 // The definition of this constant is weak, which allows us to inject a
 // different value for it at link time.
-extern "C" const bool kAbslContainerInternalSampleEverything;
+extern "C" bool AbslContainerInternalSampleEverything();
 
 }  // namespace container_internal
 }  // namespace absl
diff --git a/absl/container/internal/hashtablez_sampler_force_weak_definition.cc b/absl/container/internal/hashtablez_sampler_force_weak_definition.cc
index 4ca6ffd..984dce5 100644
--- a/absl/container/internal/hashtablez_sampler_force_weak_definition.cc
+++ b/absl/container/internal/hashtablez_sampler_force_weak_definition.cc
@@ -20,8 +20,9 @@ namespace absl {
 namespace container_internal {
 
 // See hashtablez_sampler.h for details.
-extern "C" ABSL_ATTRIBUTE_WEAK const bool
-    kAbslContainerInternalSampleEverything = false;
+extern "C" ABSL_ATTRIBUTE_WEAK bool AbslContainerInternalSampleEverything() {
+  return false;
+}
 
 }  // namespace container_internal
 }  // namespace absl