From 25597bdfc148e91e27678ec30efa52f4fc8c164f Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 2 Oct 2019 15:20:57 -0700 Subject: Export of internal Abseil changes -- 3e60f355db5afd7a864591d81a6c383b6c0a0780 by Samuel Benzaquen : Internal change PiperOrigin-RevId: 272531442 -- 6d189240b8cebe3a390c730de491156d03049229 by Andy Getzendanner : 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 -- d01b14fc06bc75b41c51976ed32e7c304ea1aab7 by Abseil Team : exclude emscripten from running tests involving long doubles PiperOrigin-RevId: 272497628 GitOrigin-RevId: 3e60f355db5afd7a864591d81a6c383b6c0a0780 Change-Id: I3c8a8f5acaf7652a06ef40cf028ef5d2e142f81b --- absl/container/internal/hashtablez_sampler.cc | 20 +++++++++++++++++++- absl/container/internal/hashtablez_sampler.h | 2 +- .../hashtablez_sampler_force_weak_definition.cc | 5 +++-- 3 files changed, 23 insertions(+), 4 deletions(-) (limited to 'absl/container') 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 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 -- cgit v1.2.3