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authorGravatar Abseil Team <absl-team@google.com>2019-01-07 09:01:16 -0800
committerGravatar Shaindel Schwartz <shaindel@google.com>2019-01-07 15:22:43 -0500
commitb16aeb6756bdab08cdf12d40baab5b51f7d15b16 (patch)
tree5c5130ba335b32dd5df880fe4089bf847088b562 /absl/base/internal
parent7ffbe09f3d85504bd018783bbe1e2c12992fe47c (diff)
Export of internal Abseil changes.
-- 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 by Samuel Benzaquen <sbenza@google.com>: Fix uninitialized member in the `iterator` class by using a union of the two possible states of the iterator. This silences a Wuninitialized warning in gcc>=7. PiperOrigin-RevId: 228175148 -- 98b4e3204c0ec3cfd4cb037e24d443ea4b63fc84 by CJ Johnson <johnsoncj@google.com>: Factors out the implementation of InlinedVector::swap(...) into a private member function PiperOrigin-RevId: 228173383 -- f1432ad3a8b05285c6d55bc4754cfae765485b7f by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 227891984 -- 03fc00c7a4efc6000e6d9125cb2e252bffda76fe by Andy Getzendanner <durandal@google.com>: Add a missing linebreak to a comment and markdownify two unordered lists. PiperOrigin-RevId: 227861389 -- 0d66c9afba4fc9aa52e61d9fb410e165018a7b48 by Abseil Team <absl-team@google.com>: Add an API to register a new source for the cycle clock. PiperOrigin-RevId: 227779218 -- 14d3f9b70c8818b8541e5fb2f6ca4c59d479de31 by Andy Getzendanner <durandal@google.com>: Correct a typo in a stripping marker. PiperOrigin-RevId: 227750014 -- 59df88740f4e315beb57a8772f8bcf7879440c74 by Matt Kulukundis <kfm@google.com>: Switch thread local handling to be more cross platform PiperOrigin-RevId: 227695133 -- 75deed5bfcb5c42534e933f104aa7d94e11e348d by Abseil Team <absl-team@google.com>: Rollback workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227689133 -- 54994bf0afec026e6e0e7a199df0bbb4b7d9a4aa by Derek Mauro <dmauro@google.com>: Add -pthread to linkopts where it actually belongs, on the library that uses it. Fixes https://github.com/abseil/abseil-cpp/issues/240. PiperOrigin-RevId: 227612492 -- 893875f3536b7e0a1bad993aa6b2e083abb3b25a by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227582833 -- 506c9b8e9002ca3389c7040473b68d4cbf94bdcc by Matt Kulukundis <kfm@google.com>: Workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227561449 -- 29ee90d96dfe3114cf93f9bb92ea0cc9e768a407 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227054634 GitOrigin-RevId: 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 Change-Id: Ibc90566d92ee6e0ad7e150f513ec7f5d22ec0a94
Diffstat (limited to 'absl/base/internal')
-rw-r--r--absl/base/internal/cycleclock.cc12
-rw-r--r--absl/base/internal/cycleclock.h14
-rw-r--r--absl/base/internal/per_thread_tls.h12
3 files changed, 33 insertions, 5 deletions
diff --git a/absl/base/internal/cycleclock.cc b/absl/base/internal/cycleclock.cc
index a742df0..9eb13b8 100644
--- a/absl/base/internal/cycleclock.cc
+++ b/absl/base/internal/cycleclock.cc
@@ -22,6 +22,7 @@
#include "absl/base/internal/cycleclock.h"
+#include <atomic>
#include <chrono> // NOLINT(build/c++11)
#include "absl/base/internal/unscaledcycleclock.h"
@@ -52,17 +53,26 @@ static constexpr int32_t kShift = 2;
#endif
static constexpr double kFrequencyScale = 1.0 / (1 << kShift);
+static std::atomic<CycleClockSourceFunc> cycle_clock_source;
} // namespace
int64_t CycleClock::Now() {
- return base_internal::UnscaledCycleClock::Now() >> kShift;
+ auto fn = cycle_clock_source.load(std::memory_order_relaxed);
+ if (fn == nullptr) {
+ return base_internal::UnscaledCycleClock::Now() >> kShift;
+ }
+ return fn() >> kShift;
}
double CycleClock::Frequency() {
return kFrequencyScale * base_internal::UnscaledCycleClock::Frequency();
}
+void CycleClockSource::Register(CycleClockSourceFunc source) {
+ cycle_clock_source.store(source, std::memory_order_relaxed);
+}
+
#else
int64_t CycleClock::Now() {
diff --git a/absl/base/internal/cycleclock.h b/absl/base/internal/cycleclock.h
index 60e9715..9853a66 100644
--- a/absl/base/internal/cycleclock.h
+++ b/absl/base/internal/cycleclock.h
@@ -71,6 +71,20 @@ class CycleClock {
CycleClock& operator=(const CycleClock&) = delete;
};
+using CycleClockSourceFunc = int64_t (*)();
+
+class CycleClockSource {
+ private:
+ // CycleClockSource::Register()
+ //
+ // Register a function that provides an alternate source for the unscaled CPU
+ // cycle count value. The source function must be async signal safe, must not
+ // call CycleClock::Now(), and must have a frequency that matches that of the
+ // unscaled clock used by CycleClock. A nullptr value resets CycleClock to use
+ // the default source.
+ static void Register(CycleClockSourceFunc source);
+};
+
} // namespace base_internal
} // namespace absl
diff --git a/absl/base/internal/per_thread_tls.h b/absl/base/internal/per_thread_tls.h
index 2428bdc..5635985 100644
--- a/absl/base/internal/per_thread_tls.h
+++ b/absl/base/internal/per_thread_tls.h
@@ -16,13 +16,17 @@
#define ABSL_BASE_INTERNAL_PER_THREAD_TLS_H_
// This header defines two macros:
+//
// If the platform supports thread-local storage:
-// ABSL_PER_THREAD_TLS_KEYWORD is the C keyword needed to declare a
-// thread-local variable ABSL_PER_THREAD_TLS is 1
+//
+// * ABSL_PER_THREAD_TLS_KEYWORD is the C keyword needed to declare a
+// thread-local variable
+// * ABSL_PER_THREAD_TLS is 1
//
// Otherwise:
-// ABSL_PER_THREAD_TLS_KEYWORD is empty
-// ABSL_PER_THREAD_TLS is 0
+//
+// * ABSL_PER_THREAD_TLS_KEYWORD is empty
+// * ABSL_PER_THREAD_TLS is 0
//
// Microsoft C supports thread-local storage.
// GCC supports it if the appropriate version of glibc is available,