Export of internal Abseil changes

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a5af5874c1c5cc02bd2a748d455321f82b6f2a93 by Andy Getzendanner <durandal@google.com>:

fix compile fails with asan and -Wredundant-decls

Import of https://github.com/abseil/abseil-cpp/pull/801

PiperOrigin-RevId: 336693223

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ed9df42ab2b742386c6692c2bed015374c919d9c by Derek Mauro <dmauro@google.com>:

Fix integer conversion warning

Fixes #814

PiperOrigin-RevId: 336651814

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0ab4c23884e72dce17b67c1eb520f9dbb802565d by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 336585378

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eba0e3dccd52a6e91bcff84075bef0affc650b74 by Matt Kulukundis <kfm@google.com>:

Add bitset operations to Futex helper.

PiperOrigin-RevId: 336409368

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8b0709a8b4500bf5f0af4b602d76a298d81645e8 by Abseil Team <absl-team@google.com>:

Fix code indentation in a comment.

PiperOrigin-RevId: 336368167

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bc3961c87a7e7760c10319a5b0349c279f7ae3ad by Samuel Benzaquen <sbenza@google.com>:

Improve performance of the registry:
 - Reduce contention
 - Reduce memory usage for each flag by `6*sizeof(void*)`.
 - Replace one immortal allocation per-flag with a single one for all the flags
 - Slightly improve single-threaded performance by avoiding the std::map indirections.

PiperOrigin-RevId: 336365904

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264ad9f28f935aad8b6b1437f8bf804fa9104346 by Abseil Team <absl-team@google.com>:

Fix typo in comment on absl::Condition.

PiperOrigin-RevId: 336311680

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b5b808a8c75ca0df7b09eff9a423ec171d80f771 by Derek Mauro <dmauro@google.com>:

Add missing Apache license headers

PiperOrigin-RevId: 336294980

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89446c3a4793df8b95060385cf3e219357c3db1d by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 336287465

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57c8be4e294881bc79a6a44b8e4bf7ecbb19b9b9 by Matt Kulukundis <kfm@google.com>:

Extract Futex from an implementation detail of Wait to a private interface.

PiperOrigin-RevId: 336123209
GitOrigin-RevId: a5af5874c1c5cc02bd2a748d455321f82b6f2a93
Change-Id: Ie5a0ebe28e571814e3e11d4c05ca308523ccf311

1 files changed, 33 insertions, 0 deletions

diff --git a/absl/flags/flag_benchmark.cc b/absl/flags/flag_benchmark.cc
index 7b52c9bc..9982b604 100644
--- a/absl/flags/flag_benchmark.cc
+++ b/absl/flags/flag_benchmark.cc
@@ -20,6 +20,8 @@
 
 #include "absl/flags/flag.h"
 #include "absl/flags/marshalling.h"
+#include "absl/flags/parse.h"
+#include "absl/flags/reflection.h"
 #include "absl/strings/string_view.h"
 #include "absl/time/time.h"
 #include "absl/types/optional.h"
@@ -103,6 +105,23 @@ std::string AbslUnparseFlag(const UDT&) { return ""; }
 
 BENCHMARKED_TYPES(FLAG_DEF)
 
+// Register thousands of flags to bloat up the size of the registry.
+// This mimics real life production binaries.
+#define DEFINE_FLAG_0(name) ABSL_FLAG(int, name, 0, "");
+#define DEFINE_FLAG_1(name) DEFINE_FLAG_0(name##0) DEFINE_FLAG_0(name##1)
+#define DEFINE_FLAG_2(name) DEFINE_FLAG_1(name##0) DEFINE_FLAG_1(name##1)
+#define DEFINE_FLAG_3(name) DEFINE_FLAG_2(name##0) DEFINE_FLAG_2(name##1)
+#define DEFINE_FLAG_4(name) DEFINE_FLAG_3(name##0) DEFINE_FLAG_3(name##1)
+#define DEFINE_FLAG_5(name) DEFINE_FLAG_4(name##0) DEFINE_FLAG_4(name##1)
+#define DEFINE_FLAG_6(name) DEFINE_FLAG_5(name##0) DEFINE_FLAG_5(name##1)
+#define DEFINE_FLAG_7(name) DEFINE_FLAG_6(name##0) DEFINE_FLAG_6(name##1)
+#define DEFINE_FLAG_8(name) DEFINE_FLAG_7(name##0) DEFINE_FLAG_7(name##1)
+#define DEFINE_FLAG_9(name) DEFINE_FLAG_8(name##0) DEFINE_FLAG_8(name##1)
+#define DEFINE_FLAG_10(name) DEFINE_FLAG_9(name##0) DEFINE_FLAG_9(name##1)
+#define DEFINE_FLAG_11(name) DEFINE_FLAG_10(name##0) DEFINE_FLAG_10(name##1)
+#define DEFINE_FLAG_12(name) DEFINE_FLAG_11(name##0) DEFINE_FLAG_11(name##1)
+DEFINE_FLAG_12(bloat_flag_);
+
 namespace {
 
 #define BM_GetFlag(T)                                            \
@@ -115,6 +134,20 @@ namespace {
 
 BENCHMARKED_TYPES(BM_GetFlag)
 
+void BM_ThreadedFindCommandLineFlag(benchmark::State& state) {
+  char dummy[] = "dummy";
+  char* argv[] = {dummy};
+  // We need to ensure that flags have been parsed. That is where the registry
+  // is finalized.
+  absl::ParseCommandLine(1, argv);
+
+  for (auto s : state) {
+    benchmark::DoNotOptimize(
+        absl::FindCommandLineFlag("bloat_flag_010101010101"));
+  }
+}
+BENCHMARK(BM_ThreadedFindCommandLineFlag)->ThreadRange(1, 16);
+
 }  // namespace
 
 #define InvokeGetFlag(T)                                               \