Export of internal Abseil changes

--
c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>:

Remove a floating point division by zero test.

This isn't testing behavior related to the library, and MSVC warns
about it in opt mode.

PiperOrigin-RevId: 285220804

--
68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>:

This CL introduces following changes to the class FlagImpl:
* We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately.
* CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now.
* Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call.
* We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced.

PiperOrigin-RevId: 285132636

--
ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>:

Change null-term* (and nul-term*) to NUL-term* in comments

PiperOrigin-RevId: 285036610

--
729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>:

Use the Posix implementation of thread identity on MinGW.
Some versions of MinGW suffer from thread_local bugs.

PiperOrigin-RevId: 285022920

--
39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>:

Implementation detail change.

Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil.

PiperOrigin-RevId: 285012012
GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c
Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1

26 files changed, 54 insertions, 2 deletions

diff --git a/absl/synchronization/BUILD.bazel b/absl/synchronization/BUILD.bazel
index 36dc98f3..3f876b9f 100644
--- a/absl/synchronization/BUILD.bazel
+++ b/absl/synchronization/BUILD.bazel
@@ -43,6 +43,7 @@ cc_library(
     deps = [
         "//absl/base",
         "//absl/base:base_internal",
+        "//absl/base:config",
         "//absl/base:core_headers",
         "//absl/base:malloc_internal",
         "//absl/base:raw_logging_internal",
diff --git a/absl/synchronization/CMakeLists.txt b/absl/synchronization/CMakeLists.txt
index 3c47a1bc..dfe5d05d 100644
--- a/absl/synchronization/CMakeLists.txt
+++ b/absl/synchronization/CMakeLists.txt
@@ -26,6 +26,7 @@ absl_cc_library(
   DEPS
     absl::base
     absl::base_internal
+    absl::config
     absl::core_headers
     absl::malloc_internal
     absl::raw_logging_internal
diff --git a/absl/synchronization/barrier.cc b/absl/synchronization/barrier.cc
index c2c539ac..0dfd795e 100644
--- a/absl/synchronization/barrier.cc
+++ b/absl/synchronization/barrier.cc
@@ -18,6 +18,7 @@
 #include "absl/synchronization/mutex.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 // Return whether int *arg is zero.
 static bool IsZero(void *arg) {
@@ -47,4 +48,5 @@ bool Barrier::Block() {
   return this->num_to_exit_ == 0;
 }
 
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/barrier.h b/absl/synchronization/barrier.h
index cb5d821a..d8e75440 100644
--- a/absl/synchronization/barrier.h
+++ b/absl/synchronization/barrier.h
@@ -23,6 +23,7 @@
 #include "absl/synchronization/mutex.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 // Barrier
 //
@@ -73,5 +74,6 @@ class Barrier {
   int num_to_exit_ ABSL_GUARDED_BY(lock_);
 };
 
+ABSL_NAMESPACE_END
 }  // namespace absl
 #endif  // ABSL_SYNCHRONIZATION_BARRIER_H_
diff --git a/absl/synchronization/blocking_counter.cc b/absl/synchronization/blocking_counter.cc
index 481a06b2..3cea7aed 100644
--- a/absl/synchronization/blocking_counter.cc
+++ b/absl/synchronization/blocking_counter.cc
@@ -17,6 +17,7 @@
 #include "absl/base/internal/raw_logging.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 // Return whether int *arg is zero.
 static bool IsZero(void *arg) {
@@ -52,4 +53,5 @@ void BlockingCounter::Wait() {
   // after we return from this method.
 }
 
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/blocking_counter.h b/absl/synchronization/blocking_counter.h
index 77560fc0..1f53f9f2 100644
--- a/absl/synchronization/blocking_counter.h
+++ b/absl/synchronization/blocking_counter.h
@@ -24,6 +24,7 @@
 #include "absl/synchronization/mutex.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 // BlockingCounter
 //
@@ -92,6 +93,7 @@ class BlockingCounter {
   int num_waiting_ ABSL_GUARDED_BY(lock_);
 };
 
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_SYNCHRONIZATION_BLOCKING_COUNTER_H_
diff --git a/absl/synchronization/blocking_counter_test.cc b/absl/synchronization/blocking_counter_test.cc
index c63e3392..2926224a 100644
--- a/absl/synchronization/blocking_counter_test.cc
+++ b/absl/synchronization/blocking_counter_test.cc
@@ -22,6 +22,7 @@
 #include "absl/time/time.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace {
 
 void PauseAndDecreaseCounter(BlockingCounter* counter, int* done) {
@@ -63,4 +64,5 @@ TEST(BlockingCounterTest, BasicFunctionality) {
 }
 
 }  // namespace
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/internal/create_thread_identity.cc b/absl/synchronization/internal/create_thread_identity.cc
index ec49d1ca..fa0070a9 100644
--- a/absl/synchronization/internal/create_thread_identity.cc
+++ b/absl/synchronization/internal/create_thread_identity.cc
@@ -27,6 +27,7 @@
 #include "absl/synchronization/internal/per_thread_sem.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 // ThreadIdentity storage is persistent, we maintain a free-list of previously
@@ -133,6 +134,7 @@ base_internal::ThreadIdentity* CreateThreadIdentity() {
 }
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_LOW_LEVEL_ALLOC_MISSING
diff --git a/absl/synchronization/internal/create_thread_identity.h b/absl/synchronization/internal/create_thread_identity.h
index 97237a6e..e121f683 100644
--- a/absl/synchronization/internal/create_thread_identity.h
+++ b/absl/synchronization/internal/create_thread_identity.h
@@ -29,6 +29,7 @@
 #include "absl/base/port.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 // Allocates and attaches a ThreadIdentity object for the calling thread.
@@ -53,6 +54,7 @@ inline base_internal::ThreadIdentity* GetOrCreateCurrentThreadIdentity() {
 }
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_SYNCHRONIZATION_INTERNAL_CREATE_THREAD_IDENTITY_H_
diff --git a/absl/synchronization/internal/graphcycles.cc b/absl/synchronization/internal/graphcycles.cc
index 0c8c7564..6a2bcdf6 100644
--- a/absl/synchronization/internal/graphcycles.cc
+++ b/absl/synchronization/internal/graphcycles.cc
@@ -44,6 +44,7 @@
 // Do not use STL.   This module does not use standard memory allocation.
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 namespace {
@@ -690,6 +691,7 @@ int GraphCycles::GetStackTrace(GraphId id, void*** ptr) {
 }
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_LOW_LEVEL_ALLOC_MISSING
diff --git a/absl/synchronization/internal/graphcycles.h b/absl/synchronization/internal/graphcycles.h
index e08dc09d..ceba33e4 100644
--- a/absl/synchronization/internal/graphcycles.h
+++ b/absl/synchronization/internal/graphcycles.h
@@ -40,7 +40,10 @@
 
 #include <cstdint>
 
+#include "absl/base/config.h"
+
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 // Opaque identifier for a graph node.
@@ -132,6 +135,7 @@ class GraphCycles {
 };
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif
diff --git a/absl/synchronization/internal/graphcycles_test.cc b/absl/synchronization/internal/graphcycles_test.cc
index 58e8477b..74eaffe7 100644
--- a/absl/synchronization/internal/graphcycles_test.cc
+++ b/absl/synchronization/internal/graphcycles_test.cc
@@ -25,6 +25,7 @@
 #include "absl/base/macros.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 // We emulate a GraphCycles object with a node vector and an edge vector.
@@ -459,4 +460,5 @@ TEST_F(GraphCyclesTest, ManyEdges) {
 }
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/internal/kernel_timeout.h b/absl/synchronization/internal/kernel_timeout.h
index 61c72e75..d6ac5db0 100644
--- a/absl/synchronization/internal/kernel_timeout.h
+++ b/absl/synchronization/internal/kernel_timeout.h
@@ -34,6 +34,7 @@
 #include "absl/time/time.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 class Futex;
@@ -148,6 +149,7 @@ class KernelTimeout {
 };
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_
diff --git a/absl/synchronization/internal/mutex_nonprod.cc b/absl/synchronization/internal/mutex_nonprod.cc
index 267deaff..4590b98d 100644
--- a/absl/synchronization/internal/mutex_nonprod.cc
+++ b/absl/synchronization/internal/mutex_nonprod.cc
@@ -31,6 +31,7 @@
 #include "absl/time/time.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 namespace {
@@ -315,4 +316,5 @@ bool Condition::Eval() const {
 
 void RegisterSymbolizer(bool (*)(const void*, char*, int)) {}
 
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/internal/mutex_nonprod.inc b/absl/synchronization/internal/mutex_nonprod.inc
index b8d5af79..85dae0ff 100644
--- a/absl/synchronization/internal/mutex_nonprod.inc
+++ b/absl/synchronization/internal/mutex_nonprod.inc
@@ -36,6 +36,7 @@
 #endif
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 class Condition;
 
 namespace synchronization_internal {
@@ -256,4 +257,5 @@ class SynchronizationStorage {
 };
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/internal/per_thread_sem.cc b/absl/synchronization/internal/per_thread_sem.cc
index 2a78b20f..821ca9b4 100644
--- a/absl/synchronization/internal/per_thread_sem.cc
+++ b/absl/synchronization/internal/per_thread_sem.cc
@@ -25,6 +25,7 @@
 #include "absl/synchronization/internal/waiter.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 void PerThreadSem::SetThreadBlockedCounter(std::atomic<int> *counter) {
@@ -62,6 +63,7 @@ void PerThreadSem::Tick(base_internal::ThreadIdentity *identity) {
 }
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 extern "C" {
diff --git a/absl/synchronization/internal/per_thread_sem.h b/absl/synchronization/internal/per_thread_sem.h
index 113cdfb7..8ab43915 100644
--- a/absl/synchronization/internal/per_thread_sem.h
+++ b/absl/synchronization/internal/per_thread_sem.h
@@ -32,6 +32,7 @@
 #include "absl/synchronization/internal/kernel_timeout.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 class Mutex;
 
@@ -85,6 +86,7 @@ class PerThreadSem {
 };
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 // In some build configurations we pass --detect-odr-violations to the
diff --git a/absl/synchronization/internal/per_thread_sem_test.cc b/absl/synchronization/internal/per_thread_sem_test.cc
index dba72390..b5a2f6d4 100644
--- a/absl/synchronization/internal/per_thread_sem_test.cc
+++ b/absl/synchronization/internal/per_thread_sem_test.cc
@@ -33,6 +33,7 @@
 // primitives which might use PerThreadSem, most notably absl::Mutex.
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 class SimpleSemaphore {
@@ -175,4 +176,5 @@ TEST_F(PerThreadSemTest, Timeouts) {
 }  // namespace
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/internal/thread_pool.h b/absl/synchronization/internal/thread_pool.h
index a00f2be8..0cb96dac 100644
--- a/absl/synchronization/internal/thread_pool.h
+++ b/absl/synchronization/internal/thread_pool.h
@@ -26,6 +26,7 @@
 #include "absl/synchronization/mutex.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 // A simple ThreadPool implementation for tests.
@@ -86,6 +87,7 @@ class ThreadPool {
 };
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
diff --git a/absl/synchronization/internal/waiter.cc b/absl/synchronization/internal/waiter.cc
index e7000d3a..ddd6081e 100644
--- a/absl/synchronization/internal/waiter.cc
+++ b/absl/synchronization/internal/waiter.cc
@@ -49,6 +49,7 @@
 #include "absl/synchronization/internal/kernel_timeout.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 static void MaybeBecomeIdle() {
@@ -481,4 +482,5 @@ void Waiter::InternalCondVarPoke() {
 #endif
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/internal/waiter.h b/absl/synchronization/internal/waiter.h
index 9540598b..5af5c282 100644
--- a/absl/synchronization/internal/waiter.h
+++ b/absl/synchronization/internal/waiter.h
@@ -62,6 +62,7 @@
 #endif
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace synchronization_internal {
 
 // Waiter is an OS-specific semaphore.
@@ -157,6 +158,7 @@ class Waiter {
 };
 
 }  // namespace synchronization_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_SYNCHRONIZATION_INTERNAL_WAITER_H_
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 100def2d..46af8a52 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -71,6 +71,7 @@ ABSL_ATTRIBUTE_WEAK void AbslInternalMutexYield() { std::this_thread::yield(); }
 }  // extern "C"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 namespace {
 
@@ -295,7 +296,7 @@ static struct SynchEvent {     // this is a trivial hash table for the events
   bool log;             // logging turned on
 
   // Constant after initialization
-  char name[1];         // actually longer---null-terminated std::string
+  char name[1];         // actually longer---NUL-terminated std::string
 } * synch_event[kNSynchEvent] ABSL_GUARDED_BY(synch_event_mu);
 
 // Ensure that the object at "addr" has a SynchEvent struct associated with it,
@@ -2720,4 +2721,5 @@ bool Condition::GuaranteedEqual(const Condition *a, const Condition *b) {
          a->arg_ == b->arg_ && a->method_ == b->method_;
 }
 
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/mutex.h b/absl/synchronization/mutex.h
index ccd94618..8c70c4ce 100644
--- a/absl/synchronization/mutex.h
+++ b/absl/synchronization/mutex.h
@@ -82,6 +82,7 @@
 #endif
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 class Condition;
 struct SynchWaitParams;
@@ -1000,7 +1001,7 @@ void RegisterCondVarTracer(void (*fn)(const char *msg, const void *cv));
 //
 // 'pc' is the program counter being symbolized, 'out' is the buffer to write
 // into, and 'out_size' is the size of the buffer.  This function can return
-// false if symbolizing failed, or true if a null-terminated symbol was written
+// false if symbolizing failed, or true if a NUL-terminated symbol was written
 // to 'out.'
 //
 // This has the same memory ordering concerns as RegisterMutexProfiler() above.
@@ -1039,6 +1040,7 @@ enum class OnDeadlockCycle {
 // the manner chosen here.
 void SetMutexDeadlockDetectionMode(OnDeadlockCycle mode);
 
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 // In some build configurations we pass --detect-odr-violations to the
diff --git a/absl/synchronization/notification.cc b/absl/synchronization/notification.cc
index 1eb7f416..e91b9038 100644
--- a/absl/synchronization/notification.cc
+++ b/absl/synchronization/notification.cc
@@ -22,6 +22,7 @@
 #include "absl/time/time.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 void Notification::Notify() {
   MutexLock l(&this->mutex_);
@@ -73,4 +74,5 @@ bool Notification::WaitForNotificationWithDeadline(absl::Time deadline) const {
   return notified;
 }
 
+ABSL_NAMESPACE_END
 }  // namespace absl
diff --git a/absl/synchronization/notification.h b/absl/synchronization/notification.h
index 36c2ce3d..9a354ca2 100644
--- a/absl/synchronization/notification.h
+++ b/absl/synchronization/notification.h
@@ -57,6 +57,7 @@
 #include "absl/time/time.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 // -----------------------------------------------------------------------------
 // Notification
@@ -116,6 +117,7 @@ class Notification {
   std::atomic<bool> notified_yet_;  // written under mutex_
 };
 
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_SYNCHRONIZATION_NOTIFICATION_H_
diff --git a/absl/synchronization/notification_test.cc b/absl/synchronization/notification_test.cc
index 059d4cd2..100ea76f 100644
--- a/absl/synchronization/notification_test.cc
+++ b/absl/synchronization/notification_test.cc
@@ -21,6 +21,7 @@
 #include "absl/synchronization/mutex.h"
 
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 
 // A thread-safe class that holds a counter.
 class ThreadSafeCounter {
@@ -128,4 +129,5 @@ TEST(NotificationTest, SanityTest) {
   BasicTests(true, &local_notification2);
 }
 
+ABSL_NAMESPACE_END
 }  // namespace absl