Export of internal Abseil changes.

--
22fceefcf070a0cf89bf1846bee16a9d36ad4161 by Derek Mauro <dmauro@google.com>:

Use function static for once initialization of flag registry.

This is a workaround for the MSVC debug constexpr initialization issue
in absl::once_flag.

GitHub #304

PiperOrigin-RevId: 248169007

--
97bbe6a5233802b61e758c55f7ba8926539cc4ca by Chris Kennelly <ckennelly@google.com>:

Internal change

PiperOrigin-RevId: 248139347

--
e72640ee079b9fa44e2c7f925fa0a608bcfea515 by Derek Mauro <dmauro@google.com>:

Re-write flags config. It doesn't have to be written in the convoluted
way it currently is in the opensource-only code path.

PiperOrigin-RevId: 248010502

--
2a72552511b8086c78cb43012c1644e519b3807e by Abseil Team <absl-team@google.com>:

Handle pthread_getschedparam() failure.

Log an error message if pthread_getschedparam() fails.

In Android's Media Framework, libminijail (which I believe is a sandbox)
aborts the process if pthread_getschedparam() is called:

  media.swcodec: libminijail[7526]: blocked syscall: sched_getparam
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  /system/bin/tombstoned: received crash request for pid 7526

Although this CL cannot handle that extreme failure mode, it handles an
error return from pthread_getschedparam() and won't use the uninitialized
param.sched_priority value in that case.

PiperOrigin-RevId: 247999953

--
bb154a92be37987d00d652c7c792594f2f515d83 by Abseil Team <absl-team@google.com>:

Allow intrinsic int128 to be set for __aarch64__ targets.

PiperOrigin-RevId: 247977594
GitOrigin-RevId: 22fceefcf070a0cf89bf1846bee16a9d36ad4161
Change-Id: I1f7ccfd82eb71446277a8e6f542fe835ac173d71

8 files changed, 114 insertions, 45 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 317452da7af7..c6f0e4d63860 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -18,9 +18,9 @@ load(
     "//absl:copts/configure_copts.bzl",
     "ABSL_DEFAULT_COPTS",
     "ABSL_DEFAULT_LINKOPTS",
-    "ABSL_TEST_COPTS",
     "ABSL_EXCEPTIONS_FLAG",
     "ABSL_EXCEPTIONS_FLAG_LINKOPTS",
+    "ABSL_TEST_COPTS",
 )
 
 package(default_visibility = ["//visibility:public"])
diff --git a/absl/base/config.h b/absl/base/config.h
index 3b81e269ddeb..2a14fe740630 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -191,15 +191,13 @@
 // * On Clang:
 //   * Building using Clang for Windows, where the Clang runtime library has
 //     128-bit support only on LP64 architectures, but Windows is LLP64.
-//   * Building for aarch64, where __int128 exists but has exhibits a sporadic
-//     compiler crashing bug.
 // * On Nvidia's nvcc:
 //   * nvcc also defines __GNUC__ and __SIZEOF_INT128__, but not all versions
 //     actually support __int128.
 #ifdef ABSL_HAVE_INTRINSIC_INT128
 #error ABSL_HAVE_INTRINSIC_INT128 cannot be directly set
 #elif defined(__SIZEOF_INT128__)
-#if (defined(__clang__) && !defined(_WIN32) && !defined(__aarch64__)) || \
+#if (defined(__clang__) && !defined(_WIN32)) || \
     (defined(__CUDACC__) && __CUDACC_VER_MAJOR__ >= 9) ||                \
     (defined(__GNUC__) && !defined(__clang__) && !defined(__CUDACC__))
 #define ABSL_HAVE_INTRINSIC_INT128 1
diff --git a/absl/flags/BUILD.bazel b/absl/flags/BUILD.bazel
index 2d868b0ab8bb..bb1a7aacde64 100644
--- a/absl/flags/BUILD.bazel
+++ b/absl/flags/BUILD.bazel
@@ -220,6 +220,20 @@ cc_test(
 )
 
 cc_test(
+    name = "config_test",
+    size = "small",
+    srcs = [
+        "config_test.cc",
+    ],
+    copts = ABSL_TEST_COPTS,
+    linkopts = ABSL_DEFAULT_LINKOPTS,
+    deps = [
+        ":config",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
+cc_test(
     name = "flag_test",
     size = "small",
     srcs = [
diff --git a/absl/flags/CMakeLists.txt b/absl/flags/CMakeLists.txt
index 284d6279b19a..9e0b441b350c 100644
--- a/absl/flags/CMakeLists.txt
+++ b/absl/flags/CMakeLists.txt
@@ -203,6 +203,18 @@ absl_cc_test(
 
 absl_cc_test(
   NAME
+    flags_config_test
+  SRCS
+    "config_test.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::flags_config
+    gtest_main
+)
+
+absl_cc_test(
+  NAME
     flags_flag_test
   SRCS
     "flag_test.cc"
diff --git a/absl/flags/config.h b/absl/flags/config.h
index a734af4688de..a9fd97ad0f37 100644
--- a/absl/flags/config.h
+++ b/absl/flags/config.h
@@ -17,38 +17,32 @@
 #define ABSL_FLAGS_CONFIG_H_
 
 // Determine if we should strip string literals from the Flag objects.
+// By default we strip string literals on mobile platforms.
 #if !defined(ABSL_FLAGS_STRIP_NAMES)
 
-// Non-mobile linux platforms don't strip string literals.
-#if (defined(__linux__) || defined(__Fuchsia__)) && !defined(__ANDROID__)
-#define ABSL_FLAGS_STRIP_NAMES 0
+#if defined(__ANDROID__)
+#define ABSL_FLAGS_STRIP_NAMES 1
 
-// So do Macs (not iOS or embedded Apple platforms).
 #elif defined(__APPLE__)
 #include <TargetConditionals.h>
-#if !TARGET_OS_IPHONE && !TARGET_OS_EMBEDDED
-#define ABSL_FLAGS_STRIP_NAMES 0
+#if defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
+#define ABSL_FLAGS_STRIP_NAMES 1
+#elif defined(TARGET_OS_EMBEDDED) && TARGET_OS_EMBEDDED
+#define ABSL_FLAGS_STRIP_NAMES 1
+#endif  // TARGET_OS_*
 #endif
 
-// And Windows.
-#elif defined(_WIN32)
-#define ABSL_FLAGS_STRIP_NAMES 0
+#endif  // !defined(ABSL_FLAGS_STRIP_NAMES)
 
-// And Myriad.
-#elif defined(__myriad2__)
+#if !defined(ABSL_FLAGS_STRIP_NAMES)
+// If ABSL_FLAGS_STRIP_NAMES wasn't set on the command line or above,
+// the default is not to strip.
 #define ABSL_FLAGS_STRIP_NAMES 0
-
 #endif
-#endif  // !defined(ABSL_FLAGS_STRIP_NAMES)
 
-#if ABSL_FLAGS_STRIP_NAMES
 #if !defined(ABSL_FLAGS_STRIP_HELP)
-#define ABSL_FLAGS_STRIP_HELP 1
-#endif
-#else
-#if !defined(ABSL_FLAGS_STRIP_HELP)
-#define ABSL_FLAGS_STRIP_HELP 0
-#endif
+// By default, if we strip names, we also strip help.
+#define ABSL_FLAGS_STRIP_HELP ABSL_FLAGS_STRIP_NAMES
 #endif
 
 #endif  // ABSL_FLAGS_CONFIG_H_
diff --git a/absl/flags/config_test.cc b/absl/flags/config_test.cc
new file mode 100644
index 000000000000..638998667e70
--- /dev/null
+++ b/absl/flags/config_test.cc
@@ -0,0 +1,61 @@
+//  Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/flags/config.h"
+
+#ifdef __APPLE__
+#include <TargetConditionals.h>
+#endif
+
+#include "gtest/gtest.h"
+
+#ifndef ABSL_FLAGS_STRIP_NAMES
+#error ABSL_FLAGS_STRIP_NAMES is not defined
+#endif
+
+#ifndef ABSL_FLAGS_STRIP_HELP
+#error ABSL_FLAGS_STRIP_HELP is not defined
+#endif
+
+namespace {
+
+// Test that ABSL_FLAGS_STRIP_NAMES and ABSL_FLAGS_STRIP_HELP are configured how
+// we expect them to be configured by default. If you override this
+// configuration, this test will fail, but the code should still be safe to use.
+TEST(FlagsConfigTest, Test) {
+#if defined(__ANDROID__)
+  EXPECT_EQ(ABSL_FLAGS_STRIP_NAMES, 1);
+  EXPECT_EQ(ABSL_FLAGS_STRIP_HELP, 1);
+#elif defined(__myriad2__)
+  EXPECT_EQ(ABSL_FLAGS_STRIP_NAMES, 0);
+  EXPECT_EQ(ABSL_FLAGS_STRIP_HELP, 0);
+#elif defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
+  EXPECT_EQ(ABSL_FLAGS_STRIP_NAMES, 1);
+  EXPECT_EQ(ABSL_FLAGS_STRIP_HELP, 1);
+#elif defined(TARGET_OS_EMBEDDED) && TARGET_OS_EMBEDDED
+  EXPECT_EQ(ABSL_FLAGS_STRIP_NAMES, 1);
+  EXPECT_EQ(ABSL_FLAGS_STRIP_HELP, 1);
+#elif defined(__APPLE__)
+  EXPECT_EQ(ABSL_FLAGS_STRIP_NAMES, 0);
+  EXPECT_EQ(ABSL_FLAGS_STRIP_HELP, 0);
+#elif defined(_WIN32)
+  EXPECT_EQ(ABSL_FLAGS_STRIP_NAMES, 0);
+  EXPECT_EQ(ABSL_FLAGS_STRIP_HELP, 0);
+#elif defined(__linux__)
+  EXPECT_EQ(ABSL_FLAGS_STRIP_NAMES, 0);
+  EXPECT_EQ(ABSL_FLAGS_STRIP_HELP, 0);
+#endif
+}
+
+}  // namespace
diff --git a/absl/flags/internal/registry.cc b/absl/flags/internal/registry.cc
index 435c5b0be330..e52cbb683b9e 100644
--- a/absl/flags/internal/registry.cc
+++ b/absl/flags/internal/registry.cc
@@ -15,7 +15,6 @@
 
 #include "absl/flags/internal/registry.h"
 
-#include "absl/base/call_once.h"
 #include "absl/base/dynamic_annotations.h"
 #include "absl/base/internal/raw_logging.h"
 #include "absl/flags/config.h"
@@ -151,12 +150,6 @@ class FlagRegistry {
 
   FlagPtrMap flag_ptr_map_;
 
-  static FlagRegistry* global_registry_;  // a singleton registry
-
-  static absl::once_flag global_registry_once_;
-
-  static void InitGlobalRegistry();
-
   absl::Mutex lock_;
 
   // Disallow
@@ -164,16 +157,9 @@ class FlagRegistry {
   FlagRegistry& operator=(const FlagRegistry&);
 };
 
-// Get the singleton FlagRegistry object
-FlagRegistry* FlagRegistry::global_registry_ = nullptr;
-absl::once_flag FlagRegistry::global_registry_once_;
-
-void FlagRegistry::InitGlobalRegistry() { global_registry_ = new FlagRegistry; }
-
 FlagRegistry* FlagRegistry::GlobalRegistry() {
-  absl::call_once(global_registry_once_, &InitGlobalRegistry);
-
-  return global_registry_;
+  static FlagRegistry* global_registry = new FlagRegistry;
+  return global_registry;
 }
 
 namespace {
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 3e8033a0b6de..76bd307a4d41 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -901,11 +901,15 @@ static PerThreadSynch *Enqueue(PerThreadSynch *head,
       // base_internal::CycleClock::Now() is 0.5%.
       int policy;
       struct sched_param param;
-      pthread_getschedparam(pthread_self(), &policy, &param);
-      s->priority = param.sched_priority;
-      s->next_priority_read_cycles =
-          now_cycles +
-          static_cast<int64_t>(base_internal::CycleClock::Frequency());
+      const int err = pthread_getschedparam(pthread_self(), &policy, &param);
+      if (err != 0) {
+        ABSL_RAW_LOG(ERROR, "pthread_getschedparam failed: %d", err);
+      } else {
+        s->priority = param.sched_priority;
+        s->next_priority_read_cycles =
+            now_cycles +
+            static_cast<int64_t>(base_internal::CycleClock::Frequency());
+      }
     }
     if (s->priority > head->priority) {  // s's priority is above head's
       // try to put s in priority-fifo order, or failing that at the front.