Export of internal Abseil changes

--
b2b94b9f533e4f9ae2a2df9de56ccb3b18f31d0d by Gennadiy Rozental <rogeeff@google.com>:

Internal change

PiperOrigin-RevId: 314366138

--
7a5ac6be82741aec5b327d7b67efd14d69deed6a by Gennadiy Rozental <rogeeff@google.com>:

Introduce Abseil prefixed dynamic annotation macros.

PiperOrigin-RevId: 314228914

--
33e7c605cb1be9bd48bd3590b1eedccd68d3bd1b by Gennadiy Rozental <rogeeff@google.com>:

Fixing missing includes and remove unnecessary ones.

PiperOrigin-RevId: 314217909

--
6a3c5c26bfa13317bf0a880f13d0e4be0b971b76 by Gennadiy Rozental <rogeeff@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 314209576

--
f7795aa68020af4a6b4905531ba951e04b88966a by Abseil Team <absl-team@google.com>:

absl::FormatTime() and absl::ParseTime() format specifiers:
- %EZ now accepts 'z' in addition to 'Z' as a synonym for +00:00.
- %ET is introduced, producing 'T' on output, and accepting 'T'
  or 't' on input.  This is for the RFC3339 date-time separator.

PiperOrigin-RevId: 313945137

--
87c437ce3aab3f59a7546e44a28cd1c8aaa152c3 by Laramie Leavitt <lar@google.com>:

Rollback

PiperOrigin-RevId: 313868206

--
8049b74349486a0026932b86d29c380b195e1cba by Laramie Leavitt <lar@google.com>:

Remove the MockingBitGenBase base class in favor of type-erasure in BitGenRef.

In Abseil random, mocking was split across two different classes,
MockingBitGenBase and MockingBitGen. This split existed because Google Mock is a
test-only library that we don't link into production, so MockingBitGenBase
provided a low-overhead scaffold used to lookup mocks when in test code, but
which is unused in production code.

That has been replaced by type-erasure which looks for a method named
CallImpl with the correct signature.

Weaken the coupling between MockingBitGen, DistributionCaller, and MockOverloadSet.

Rename CallImpl to InvokeMock()

Previously, the implementation of DistributionCaller was also split across different files using explicit instantiation of the DistributionCaller struct and some details in the Mocking classes. Now Distribution caller uses the presence of the InvokeMock() method to choose whether to use the mockable call path or the default call path.

PiperOrigin-RevId: 313848695

--
1741d80e08050e1939605f70ca6ff64809785c85 by Gennadiy Rozental <rogeeff@google.com>:

Introduce public interface to access reflection handle corresponding the flag.

This interface will be the only official way to access flag reflection information from the flag object. The other internal methods will eventually disappear.

PiperOrigin-RevId: 313734006

--
c375bead457de29d9c29595d16c66d3e5125b585 by Abseil Team <absl-team@google.com>:

Improve documentation of absl::c_partial_sort_copy.

This function takes no middle parameter, instead using the size of the result
container to determine the size of the partial sort.

PiperOrigin-RevId: 313656062

--
bbc759d43656b1b996ad558f23c852a9f14129d2 by Gennadiy Rozental <rogeeff@google.com>:

Eliminate dynamic annotation symbols in the library.

PiperOrigin-RevId: 313650817
GitOrigin-RevId: b2b94b9f533e4f9ae2a2df9de56ccb3b18f31d0d
Change-Id: Ic7a11bbcb723f3ff6a7e2f214bff0a92c6f8ab4d

5 files changed, 867 insertions, 392 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 76122dab..35cb2e94 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -115,10 +115,18 @@ cc_library(
 
 cc_library(
     name = "dynamic_annotations",
-    srcs = ["dynamic_annotations.cc"],
-    hdrs = ["dynamic_annotations.h"],
+    srcs = [
+        "dynamic_annotations.cc",
+        "internal/dynamic_annotations.h",
+    ],
+    hdrs = [
+        "dynamic_annotations.h",
+    ],
     copts = ABSL_DEFAULT_COPTS,
     linkopts = ABSL_DEFAULT_LINKOPTS,
+    deps = [
+        ":config",
+    ],
 )
 
 cc_library(
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 292998b3..b7c01c99 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -106,8 +106,11 @@ absl_cc_library(
     "dynamic_annotations.h"
   SRCS
     "dynamic_annotations.cc"
+    "internal/dynamic_annotations.h"
   COPTS
     ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
   PUBLIC
 )
 
diff --git a/absl/base/dynamic_annotations.cc b/absl/base/dynamic_annotations.cc
index 21e822e5..f26e673e 100644
--- a/absl/base/dynamic_annotations.cc
+++ b/absl/base/dynamic_annotations.cc
@@ -17,72 +17,17 @@
 
 #include "absl/base/dynamic_annotations.h"
 
-#ifndef __has_feature
-#define __has_feature(x) 0
-#endif
-
-/* Compiler-based ThreadSanitizer defines
-   DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL = 1
-   and provides its own definitions of the functions. */
+// Compiler-based ThreadSanitizer defines
+// DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL = 1
+// and provides its own definitions of the functions.
 
 #ifndef DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL
 # define DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL 0
 #endif
 
-/* Each function is empty and called (via a macro) only in debug mode.
-   The arguments are captured by dynamic tools at runtime. */
-
 #if DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL == 0 && !defined(__native_client__)
 
-#if __has_feature(memory_sanitizer)
-#include <sanitizer/msan_interface.h>
-#endif
-
-#ifdef __cplusplus
 extern "C" {
-#endif
-
-void AnnotateRWLockCreate(const char *, int,
-                          const volatile void *){}
-void AnnotateRWLockDestroy(const char *, int,
-                           const volatile void *){}
-void AnnotateRWLockAcquired(const char *, int,
-                            const volatile void *, long){}
-void AnnotateRWLockReleased(const char *, int,
-                            const volatile void *, long){}
-void AnnotateBenignRace(const char *, int,
-                        const volatile void *,
-                        const char *){}
-void AnnotateBenignRaceSized(const char *, int,
-                             const volatile void *,
-                             size_t,
-                             const char *) {}
-void AnnotateThreadName(const char *, int,
-                        const char *){}
-void AnnotateIgnoreReadsBegin(const char *, int){}
-void AnnotateIgnoreReadsEnd(const char *, int){}
-void AnnotateIgnoreWritesBegin(const char *, int){}
-void AnnotateIgnoreWritesEnd(const char *, int){}
-void AnnotateEnableRaceDetection(const char *, int, int){}
-void AnnotateMemoryIsInitialized(const char *, int,
-                                 const volatile void *mem, size_t size) {
-#if __has_feature(memory_sanitizer)
-  __msan_unpoison(mem, size);
-#else
-  (void)mem;
-  (void)size;
-#endif
-}
-
-void AnnotateMemoryIsUninitialized(const char *, int,
-                                   const volatile void *mem, size_t size) {
-#if __has_feature(memory_sanitizer)
-  __msan_allocated_memory(mem, size);
-#else
-  (void)mem;
-  (void)size;
-#endif
-}
 
 static int GetRunningOnValgrind(void) {
 #ifdef RUNNING_ON_VALGRIND
@@ -95,21 +40,21 @@ static int GetRunningOnValgrind(void) {
   return 0;
 }
 
-/* See the comments in dynamic_annotations.h */
+// See the comments in dynamic_annotations.h
 int RunningOnValgrind(void) {
   static volatile int running_on_valgrind = -1;
   int local_running_on_valgrind = running_on_valgrind;
-  /* C doesn't have thread-safe initialization of statics, and we
-     don't want to depend on pthread_once here, so hack it. */
+  // C doesn't have thread-safe initialization of statics, and we
+  // don't want to depend on pthread_once here, so hack it.
   ANNOTATE_BENIGN_RACE(&running_on_valgrind, "safe hack");
   if (local_running_on_valgrind == -1)
     running_on_valgrind = local_running_on_valgrind = GetRunningOnValgrind();
   return local_running_on_valgrind;
 }
 
-/* See the comments in dynamic_annotations.h */
+// See the comments in dynamic_annotations.h
 double ValgrindSlowdown(void) {
-  /* Same initialization hack as in RunningOnValgrind(). */
+  // Same initialization hack as in RunningOnValgrind().
   static volatile double slowdown = 0.0;
   double local_slowdown = slowdown;
   ANNOTATE_BENIGN_RACE(&slowdown, "safe hack");
@@ -123,7 +68,5 @@ double ValgrindSlowdown(void) {
   return local_slowdown;
 }
 
-#ifdef __cplusplus
 }  // extern "C"
-#endif
-#endif  /* DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL == 0 */
+#endif  // DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL == 0
diff --git a/absl/base/dynamic_annotations.h b/absl/base/dynamic_annotations.h
index 2d985260..1444dc48 100644
--- a/absl/base/dynamic_annotations.h
+++ b/absl/base/dynamic_annotations.h
@@ -1,386 +1,504 @@
-/*
- *  Copyright 2017 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.
- */
-/* This file defines dynamic annotations for use with dynamic analysis
-   tool such as valgrind, PIN, etc.
-
-   Dynamic annotation is a source code annotation that affects
-   the generated code (that is, the annotation is not a comment).
-   Each such annotation is attached to a particular
-   instruction and/or to a particular object (address) in the program.
-
-   The annotations that should be used by users are macros in all upper-case
-   (e.g., ANNOTATE_THREAD_NAME).
-
-   Actual implementation of these macros may differ depending on the
-   dynamic analysis tool being used.
-
-   This file supports the following configurations:
-   - Dynamic Annotations enabled (with static thread-safety warnings disabled).
-     In this case, macros expand to functions implemented by Thread Sanitizer,
-     when building with TSan. When not provided an external implementation,
-     dynamic_annotations.cc provides no-op implementations.
-
-   - Static Clang thread-safety warnings enabled.
-     When building with a Clang compiler that supports thread-safety warnings,
-     a subset of annotations can be statically-checked at compile-time. We
-     expand these macros to static-inline functions that can be analyzed for
-     thread-safety, but afterwards elided when building the final binary.
-
-   - All annotations are disabled.
-     If neither Dynamic Annotations nor Clang thread-safety warnings are
-     enabled, then all annotation-macros expand to empty. */
+// Copyright 2017 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.
+
+// This file defines dynamic annotations for use with dynamic analysis tool
+// such as valgrind, PIN, etc.
+//
+// Dynamic annotation is a source code annotation that affects the generated
+// code (that is, the annotation is not a comment). Each such annotation is
+// attached to a particular instruction and/or to a particular object (address)
+// in the program.
+//
+// The annotations that should be used by users are macros in all upper-case
+// (e.g., ABSL_ANNOTATE_THREAD_NAME).
+//
+// Actual implementation of these macros may differ depending on the dynamic
+// analysis tool being used.
+//
+// This file supports the following configurations:
+// - Dynamic Annotations enabled (with static thread-safety warnings disabled).
+//   In this case, macros expand to functions implemented by Thread Sanitizer,
+//   when building with TSan. When not provided an external implementation,
+//   dynamic_annotations.cc provides no-op implementations.
+//
+// - Static Clang thread-safety warnings enabled.
+//   When building with a Clang compiler that supports thread-safety warnings,
+//   a subset of annotations can be statically-checked at compile-time. We
+//   expand these macros to static-inline functions that can be analyzed for
+//   thread-safety, but afterwards elided when building the final binary.
+//
+// - All annotations are disabled.
+//   If neither Dynamic Annotations nor Clang thread-safety warnings are
+//   enabled, then all annotation-macros expand to empty.
 
 #ifndef ABSL_BASE_DYNAMIC_ANNOTATIONS_H_
 #define ABSL_BASE_DYNAMIC_ANNOTATIONS_H_
 
+#include <stddef.h>
+
+#include "absl/base/config.h"
+
+// TODO(rogeeff): Remove after the backward compatibility period.
+#include "absl/base/internal/dynamic_annotations.h"  // IWYU pragma: export
+
+// -------------------------------------------------------------------------
+// Decide which features are enabled
+
 #ifndef DYNAMIC_ANNOTATIONS_ENABLED
-# define DYNAMIC_ANNOTATIONS_ENABLED 0
+#define DYNAMIC_ANNOTATIONS_ENABLED 0
+#endif
+
+#if defined(__clang__) && !defined(SWIG)
+#define ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED 1
+#else
+#define ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED 0
 #endif
 
 #if DYNAMIC_ANNOTATIONS_ENABLED != 0
 
-  /* -------------------------------------------------------------
-     Annotations that suppress errors.  It is usually better to express the
-     program's synchronization using the other annotations, but these can
-     be used when all else fails. */
-
-  /* Report that we may have a benign race at "pointer", with size
-     "sizeof(*(pointer))". "pointer" must be a non-void* pointer.  Insert at the
-     point where "pointer" has been allocated, preferably close to the point
-     where the race happens.  See also ANNOTATE_BENIGN_RACE_STATIC. */
-  #define ANNOTATE_BENIGN_RACE(pointer, description) \
-    AnnotateBenignRaceSized(__FILE__, __LINE__, pointer, \
-                            sizeof(*(pointer)), description)
-
-  /* Same as ANNOTATE_BENIGN_RACE(address, description), but applies to
-     the memory range [address, address+size). */
-  #define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
-    AnnotateBenignRaceSized(__FILE__, __LINE__, address, size, description)
-
-  /* Enable (enable!=0) or disable (enable==0) race detection for all threads.
-     This annotation could be useful if you want to skip expensive race analysis
-     during some period of program execution, e.g. during initialization. */
-  #define ANNOTATE_ENABLE_RACE_DETECTION(enable) \
-    AnnotateEnableRaceDetection(__FILE__, __LINE__, enable)
-
-  /* -------------------------------------------------------------
-     Annotations useful for debugging. */
-
-  /* Report the current thread name to a race detector. */
-  #define ANNOTATE_THREAD_NAME(name) \
-    AnnotateThreadName(__FILE__, __LINE__, name)
-
-  /* -------------------------------------------------------------
-     Annotations useful when implementing locks.  They are not
-     normally needed by modules that merely use locks.
-     The "lock" argument is a pointer to the lock object. */
-
-  /* Report that a lock has been created at address "lock". */
-  #define ANNOTATE_RWLOCK_CREATE(lock) \
-    AnnotateRWLockCreate(__FILE__, __LINE__, lock)
-
-  /* Report that a linker initialized lock has been created at address "lock".
-   */
-#ifdef THREAD_SANITIZER
-  #define ANNOTATE_RWLOCK_CREATE_STATIC(lock) \
-    AnnotateRWLockCreateStatic(__FILE__, __LINE__, lock)
+#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 1
+#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 1
+#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 1
+#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED 0
+#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED 1
+
+#else
+
+#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 0
+#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 0
+#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 0
+
+// Clang provides limited support for static thread-safety analysis through a
+// feature called Annotalysis. We configure macro-definitions according to
+// whether Annotalysis support is available. When running in opt-mode, GCC
+// will issue a warning, if these attributes are compiled. Only include them
+// when compiling using Clang.
+
+// ANNOTALYSIS_ENABLED == 1 when IGNORE_READ_ATTRIBUTE_ENABLED == 1
+#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED \
+  ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED
+// Read/write annotations are enabled in Annotalysis mode; disabled otherwise.
+#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED \
+  ABSL_INTERNAL_ANNOTALYSIS_ENABLED
+#endif
+
+// Memory annotations are also made available to LLVM's Memory Sanitizer
+#if defined(MEMORY_SANITIZER) && defined(__has_feature) && \
+    !defined(__native_client__)
+#if __has_feature(memory_sanitizer)
+#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 1
+#endif
+#endif
+
+#ifndef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
+#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 0
+#endif
+
+#ifdef __cplusplus
+#define ABSL_INTERNAL_BEGIN_EXTERN_C extern "C" {
+#define ABSL_INTERNAL_END_EXTERN_C }  // extern "C"
+#define ABSL_INTERNAL_GLOBAL_SCOPED(F) ::F
+#define ABSL_INTERNAL_STATIC_INLINE inline
 #else
-  #define ANNOTATE_RWLOCK_CREATE_STATIC(lock) ANNOTATE_RWLOCK_CREATE(lock)
+#define ABSL_INTERNAL_BEGIN_EXTERN_C  // empty
+#define ABSL_INTERNAL_END_EXTERN_C    // empty
+#define ABSL_INTERNAL_GLOBAL_SCOPED(F) F
+#define ABSL_INTERNAL_STATIC_INLINE static inline
 #endif
 
-  /* Report that the lock at address "lock" is about to be destroyed. */
-  #define ANNOTATE_RWLOCK_DESTROY(lock) \
-    AnnotateRWLockDestroy(__FILE__, __LINE__, lock)
+// -------------------------------------------------------------------------
+// Define race annotations.
+
+#if ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 1
+
+// -------------------------------------------------------------
+// Annotations that suppress errors. It is usually better to express the
+// program's synchronization using the other annotations, but these can be used
+// when all else fails.
+
+// Report that we may have a benign race at `pointer`, with size
+// "sizeof(*(pointer))". `pointer` must be a non-void* pointer. Insert at the
+// point where `pointer` has been allocated, preferably close to the point
+// where the race happens. See also ABSL_ANNOTATE_BENIGN_RACE_STATIC.
+#define ABSL_ANNOTATE_BENIGN_RACE(pointer, description) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized)  \
+  (__FILE__, __LINE__, pointer, sizeof(*(pointer)), description)
+
+// Same as ABSL_ANNOTATE_BENIGN_RACE(`address`, `description`), but applies to
+// the memory range [`address`, `address`+`size`).
+#define ABSL_ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized)              \
+  (__FILE__, __LINE__, address, size, description)
+
+// Enable (`enable`!=0) or disable (`enable`==0) race detection for all threads.
+// This annotation could be useful if you want to skip expensive race analysis
+// during some period of program execution, e.g. during initialization.
+#define ABSL_ANNOTATE_ENABLE_RACE_DETECTION(enable)        \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateEnableRaceDetection) \
+  (__FILE__, __LINE__, enable)
+
+// -------------------------------------------------------------
+// Annotations useful for debugging.
+
+// Report the current thread `name` to a race detector.
+#define ABSL_ANNOTATE_THREAD_NAME(name) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateThreadName)(__FILE__, __LINE__, name)
+
+// -------------------------------------------------------------
+// Annotations useful when implementing locks. They are not normally needed by
+// modules that merely use locks. The `lock` argument is a pointer to the lock
+// object.
+
+// Report that a lock has been created at address `lock`.
+#define ABSL_ANNOTATE_RWLOCK_CREATE(lock) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreate)(__FILE__, __LINE__, lock)
+
+// Report that a linker initialized lock has been created at address `lock`.
+#ifdef THREAD_SANITIZER
+#define ABSL_ANNOTATE_RWLOCK_CREATE_STATIC(lock)          \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreateStatic) \
+  (__FILE__, __LINE__, lock)
+#else
+#define ABSL_ANNOTATE_RWLOCK_CREATE_STATIC(lock) \
+  ABSL_ANNOTATE_RWLOCK_CREATE(lock)
+#endif
 
-  /* Report that the lock at address "lock" has been acquired.
-     is_w=1 for writer lock, is_w=0 for reader lock. */
-  #define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) \
-    AnnotateRWLockAcquired(__FILE__, __LINE__, lock, is_w)
+// Report that the lock at address `lock` is about to be destroyed.
+#define ABSL_ANNOTATE_RWLOCK_DESTROY(lock) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockDestroy)(__FILE__, __LINE__, lock)
+
+// Report that the lock at address `lock` has been acquired.
+// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
+#define ABSL_ANNOTATE_RWLOCK_ACQUIRED(lock, is_w)     \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockAcquired) \
+  (__FILE__, __LINE__, lock, is_w)
+
+// Report that the lock at address `lock` is about to be released.
+// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
+#define ABSL_ANNOTATE_RWLOCK_RELEASED(lock, is_w)     \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockReleased) \
+  (__FILE__, __LINE__, lock, is_w)
+
+// Apply ABSL_ANNOTATE_BENIGN_RACE_SIZED to a static variable `static_var`.
+#define ABSL_ANNOTATE_BENIGN_RACE_STATIC(static_var, description)      \
+  namespace {                                                          \
+  class static_var##_annotator {                                       \
+   public:                                                             \
+    static_var##_annotator() {                                         \
+      ABSL_ANNOTATE_BENIGN_RACE_SIZED(&static_var, sizeof(static_var), \
+                                      #static_var ": " description);   \
+    }                                                                  \
+  };                                                                   \
+  static static_var##_annotator the##static_var##_annotator;           \
+  }  // namespace
+
+// Function prototypes of annotations provided by the compiler-based sanitizer
+// implementation.
+ABSL_INTERNAL_BEGIN_EXTERN_C
+void AnnotateRWLockCreate(const char* file, int line,
+                          const volatile void* lock);
+void AnnotateRWLockCreateStatic(const char* file, int line,
+                                const volatile void* lock);
+void AnnotateRWLockDestroy(const char* file, int line,
+                           const volatile void* lock);
+void AnnotateRWLockAcquired(const char* file, int line,
+                            const volatile void* lock, long is_w);  // NOLINT
+void AnnotateRWLockReleased(const char* file, int line,
+                            const volatile void* lock, long is_w);  // NOLINT
+void AnnotateBenignRace(const char* file, int line,
+                        const volatile void* address, const char* description);
+void AnnotateBenignRaceSized(const char* file, int line,
+                             const volatile void* address, size_t size,
+                             const char* description);
+void AnnotateThreadName(const char* file, int line, const char* name);
+void AnnotateEnableRaceDetection(const char* file, int line, int enable);
+ABSL_INTERNAL_END_EXTERN_C
+
+#else  // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 0
+
+#define ABSL_ANNOTATE_RWLOCK_CREATE(lock)                            // empty
+#define ABSL_ANNOTATE_RWLOCK_CREATE_STATIC(lock)                     // empty
+#define ABSL_ANNOTATE_RWLOCK_DESTROY(lock)                           // empty
+#define ABSL_ANNOTATE_RWLOCK_ACQUIRED(lock, is_w)                    // empty
+#define ABSL_ANNOTATE_RWLOCK_RELEASED(lock, is_w)                    // empty
+#define ABSL_ANNOTATE_BENIGN_RACE(address, description)              // empty
+#define ABSL_ANNOTATE_BENIGN_RACE_SIZED(address, size, description)  // empty
+#define ABSL_ANNOTATE_THREAD_NAME(name)                              // empty
+#define ABSL_ANNOTATE_ENABLE_RACE_DETECTION(enable)                  // empty
+#define ABSL_ANNOTATE_BENIGN_RACE_STATIC(static_var, description)    // empty
+
+#endif  // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
+
+// -------------------------------------------------------------------------
+// Define memory annotations.
+
+#if ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 1
+
+#include <sanitizer/msan_interface.h>
+
+#define ABSL_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
+  __msan_unpoison(address, size)
+
+#define ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
+  __msan_allocated_memory(address, size)
+
+#else  // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 0
+
+#if DYNAMIC_ANNOTATIONS_ENABLED == 1
+#define ABSL_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
+  do {                                                     \
+    (void)(address);                                       \
+    (void)(size);                                          \
+  } while (0)
+#define ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
+  do {                                                       \
+    (void)(address);                                         \
+    (void)(size);                                            \
+  } while (0)
+#else
 
-  /* Report that the lock at address "lock" is about to be released. */
-  #define ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
-    AnnotateRWLockReleased(__FILE__, __LINE__, lock, is_w)
+#define ABSL_ANNOTATE_MEMORY_IS_INITIALIZED(address, size)    // empty
+#define ABSL_ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size)  // empty
 
-#else  /* DYNAMIC_ANNOTATIONS_ENABLED == 0 */
+#endif
 
-  #define ANNOTATE_RWLOCK_CREATE(lock) /* empty */
-  #define ANNOTATE_RWLOCK_CREATE_STATIC(lock) /* empty */
-  #define ANNOTATE_RWLOCK_DESTROY(lock) /* empty */
-  #define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) /* empty */
-  #define ANNOTATE_RWLOCK_RELEASED(lock, is_w) /* empty */
-  #define ANNOTATE_BENIGN_RACE(address, description) /* empty */
-  #define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) /* empty */
-  #define ANNOTATE_THREAD_NAME(name) /* empty */
-  #define ANNOTATE_ENABLE_RACE_DETECTION(enable) /* empty */
+#endif  // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
 
-#endif  /* DYNAMIC_ANNOTATIONS_ENABLED */
+// -------------------------------------------------------------------------
+// Define IGNORE_READS_BEGIN/_END attributes.
 
-/* These annotations are also made available to LLVM's Memory Sanitizer */
-#if DYNAMIC_ANNOTATIONS_ENABLED == 1 || defined(MEMORY_SANITIZER)
-  #define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
-    AnnotateMemoryIsInitialized(__FILE__, __LINE__, address, size)
+#if ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED == 1
 
-  #define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
-    AnnotateMemoryIsUninitialized(__FILE__, __LINE__, address, size)
-#else
-  #define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) /* empty */
-  #define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) /* empty */
-#endif  /* DYNAMIC_ANNOTATIONS_ENABLED || MEMORY_SANITIZER */
+#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE \
+  __attribute((exclusive_lock_function("*")))
+#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE \
+  __attribute((unlock_function("*")))
 
-#if defined(__clang__) && !defined(SWIG)
+#else  // ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED == 0
 
-  #if DYNAMIC_ANNOTATIONS_ENABLED == 0
-    #define ANNOTALYSIS_ENABLED
-  #endif
+#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE  // empty
+#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE    // empty
 
-  /* When running in opt-mode, GCC will issue a warning, if these attributes are
-     compiled. Only include them when compiling using Clang. */
-  #define ATTRIBUTE_IGNORE_READS_BEGIN \
-      __attribute((exclusive_lock_function("*")))
-  #define ATTRIBUTE_IGNORE_READS_END \
-      __attribute((unlock_function("*")))
-#else
-  #define ATTRIBUTE_IGNORE_READS_BEGIN  /* empty */
-  #define ATTRIBUTE_IGNORE_READS_END  /* empty */
-#endif  /* defined(__clang__) && ... */
+#endif  // ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED
 
-#if (DYNAMIC_ANNOTATIONS_ENABLED != 0) || defined(ANNOTALYSIS_ENABLED)
-  #define ANNOTATIONS_ENABLED
-#endif
+// -------------------------------------------------------------------------
+// Define IGNORE_READS_BEGIN/_END annotations.
 
-#if (DYNAMIC_ANNOTATIONS_ENABLED != 0)
+#if ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED == 1
 
-  /* Request the analysis tool to ignore all reads in the current thread
-     until ANNOTATE_IGNORE_READS_END is called.
-     Useful to ignore intentional racey reads, while still checking
-     other reads and all writes.
-     See also ANNOTATE_UNPROTECTED_READ. */
-  #define ANNOTATE_IGNORE_READS_BEGIN() \
-    AnnotateIgnoreReadsBegin(__FILE__, __LINE__)
+// Request the analysis tool to ignore all reads in the current thread until
+// ABSL_ANNOTATE_IGNORE_READS_END is called. Useful to ignore intentional racey
+// reads, while still checking other reads and all writes.
+// See also ABSL_ANNOTATE_UNPROTECTED_READ.
+#define ABSL_ANNOTATE_IGNORE_READS_BEGIN() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsBegin)(__FILE__, __LINE__)
 
-  /* Stop ignoring reads. */
-  #define ANNOTATE_IGNORE_READS_END() \
-    AnnotateIgnoreReadsEnd(__FILE__, __LINE__)
+// Stop ignoring reads.
+#define ABSL_ANNOTATE_IGNORE_READS_END() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsEnd)(__FILE__, __LINE__)
 
-  /* Similar to ANNOTATE_IGNORE_READS_BEGIN, but ignore writes instead. */
-  #define ANNOTATE_IGNORE_WRITES_BEGIN() \
-    AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
+// Function prototypes of annotations provided by the compiler-based sanitizer
+// implementation.
+ABSL_INTERNAL_BEGIN_EXTERN_C
+void AnnotateIgnoreReadsBegin(const char* file, int line)
+    ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE;
+void AnnotateIgnoreReadsEnd(const char* file,
+                            int line) ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE;
+ABSL_INTERNAL_END_EXTERN_C
 
-  /* Stop ignoring writes. */
-  #define ANNOTATE_IGNORE_WRITES_END() \
-    AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
+#elif defined(ABSL_INTERNAL_ANNOTALYSIS_ENABLED)
 
-/* Clang provides limited support for static thread-safety analysis
-   through a feature called Annotalysis. We configure macro-definitions
-   according to whether Annotalysis support is available. */
-#elif defined(ANNOTALYSIS_ENABLED)
+// When Annotalysis is enabled without Dynamic Annotations, the use of
+// static-inline functions allows the annotations to be read at compile-time,
+// while still letting the compiler elide the functions from the final build.
+//
+// TODO(delesley) -- The exclusive lock here ignores writes as well, but
+// allows IGNORE_READS_AND_WRITES to work properly.
 
-  #define ANNOTATE_IGNORE_READS_BEGIN() \
-    StaticAnnotateIgnoreReadsBegin(__FILE__, __LINE__)
+#define ABSL_ANNOTATE_IGNORE_READS_BEGIN() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsBegin)()
 
-  #define ANNOTATE_IGNORE_READS_END() \
-    StaticAnnotateIgnoreReadsEnd(__FILE__, __LINE__)
+#define ABSL_ANNOTATE_IGNORE_READS_END() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsEnd)()
 
-  #define ANNOTATE_IGNORE_WRITES_BEGIN() \
-    StaticAnnotateIgnoreWritesBegin(__FILE__, __LINE__)
+ABSL_INTERNAL_STATIC_INLINE void AbslInternalAnnotateIgnoreReadsBegin()
+    ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE {}
 
-  #define ANNOTATE_IGNORE_WRITES_END() \
-    StaticAnnotateIgnoreWritesEnd(__FILE__, __LINE__)
+ABSL_INTERNAL_STATIC_INLINE void AbslInternalAnnotateIgnoreReadsEnd()
+    ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE {}
 
 #else
-  #define ANNOTATE_IGNORE_READS_BEGIN()  /* empty */
-  #define ANNOTATE_IGNORE_READS_END()  /* empty */
-  #define ANNOTATE_IGNORE_WRITES_BEGIN()  /* empty */
-  #define ANNOTATE_IGNORE_WRITES_END()  /* empty */
+
+#define ABSL_ANNOTATE_IGNORE_READS_BEGIN()  // empty
+#define ABSL_ANNOTATE_IGNORE_READS_END()    // empty
+
 #endif
 
-/* Implement the ANNOTATE_IGNORE_READS_AND_WRITES_* annotations using the more
-   primitive annotations defined above. */
-#if defined(ANNOTATIONS_ENABLED)
+// -------------------------------------------------------------------------
+// Define IGNORE_WRITES_BEGIN/_END annotations.
+
+#if ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED == 1
+
+// Similar to ABSL_ANNOTATE_IGNORE_READS_BEGIN, but ignore writes instead.
+#define ABSL_ANNOTATE_IGNORE_WRITES_BEGIN() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesBegin)(__FILE__, __LINE__)
 
-  /* Start ignoring all memory accesses (both reads and writes). */
-  #define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
-    do {                                           \
-      ANNOTATE_IGNORE_READS_BEGIN();               \
-      ANNOTATE_IGNORE_WRITES_BEGIN();              \
-    }while (0)
+// Stop ignoring writes.
+#define ABSL_ANNOTATE_IGNORE_WRITES_END() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesEnd)(__FILE__, __LINE__)
 
-  /* Stop ignoring both reads and writes. */
-  #define ANNOTATE_IGNORE_READS_AND_WRITES_END()   \
-    do {                                           \
-      ANNOTATE_IGNORE_WRITES_END();                \
-      ANNOTATE_IGNORE_READS_END();                 \
-    }while (0)
+// Function prototypes of annotations provided by the compiler-based sanitizer
+// implementation.
+ABSL_INTERNAL_BEGIN_EXTERN_C
+void AnnotateIgnoreWritesBegin(const char* file, int line);
+void AnnotateIgnoreWritesEnd(const char* file, int line);
+ABSL_INTERNAL_END_EXTERN_C
 
 #else
-  #define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN()  /* empty */
-  #define ANNOTATE_IGNORE_READS_AND_WRITES_END()  /* empty */
-#endif
 
-/* Use the macros above rather than using these functions directly. */
-#include <stddef.h>
-#ifdef __cplusplus
-extern "C" {
-#endif
-void AnnotateRWLockCreate(const char *file, int line,
-                          const volatile void *lock);
-void AnnotateRWLockCreateStatic(const char *file, int line,
-                          const volatile void *lock);
-void AnnotateRWLockDestroy(const char *file, int line,
-                           const volatile void *lock);
-void AnnotateRWLockAcquired(const char *file, int line,
-                            const volatile void *lock, long is_w);  /* NOLINT */
-void AnnotateRWLockReleased(const char *file, int line,
-                            const volatile void *lock, long is_w);  /* NOLINT */
-void AnnotateBenignRace(const char *file, int line,
-                        const volatile void *address,
-                        const char *description);
-void AnnotateBenignRaceSized(const char *file, int line,
-                        const volatile void *address,
-                        size_t size,
-                        const char *description);
-void AnnotateThreadName(const char *file, int line,
-                        const char *name);
-void AnnotateEnableRaceDetection(const char *file, int line, int enable);
-void AnnotateMemoryIsInitialized(const char *file, int line,
-                                 const volatile void *mem, size_t size);
-void AnnotateMemoryIsUninitialized(const char *file, int line,
-                                   const volatile void *mem, size_t size);
-
-/* Annotations expand to these functions, when Dynamic Annotations are enabled.
-   These functions are either implemented as no-op calls, if no Sanitizer is
-   attached, or provided with externally-linked implementations by a library
-   like ThreadSanitizer. */
-void AnnotateIgnoreReadsBegin(const char *file, int line)
-    ATTRIBUTE_IGNORE_READS_BEGIN;
-void AnnotateIgnoreReadsEnd(const char *file, int line)
-    ATTRIBUTE_IGNORE_READS_END;
-void AnnotateIgnoreWritesBegin(const char *file, int line);
-void AnnotateIgnoreWritesEnd(const char *file, int line);
-
-#if defined(ANNOTALYSIS_ENABLED)
-/* When Annotalysis is enabled without Dynamic Annotations, the use of
-   static-inline functions allows the annotations to be read at compile-time,
-   while still letting the compiler elide the functions from the final build.
-
-   TODO(delesley) -- The exclusive lock here ignores writes as well, but
-   allows IGNORE_READS_AND_WRITES to work properly. */
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wunused-function"
-static inline void StaticAnnotateIgnoreReadsBegin(const char *file, int line)
-    ATTRIBUTE_IGNORE_READS_BEGIN { (void)file; (void)line; }
-static inline void StaticAnnotateIgnoreReadsEnd(const char *file, int line)
-    ATTRIBUTE_IGNORE_READS_END { (void)file; (void)line; }
-static inline void StaticAnnotateIgnoreWritesBegin(
-    const char *file, int line) { (void)file; (void)line; }
-static inline void StaticAnnotateIgnoreWritesEnd(
-    const char *file, int line) { (void)file; (void)line; }
-#pragma GCC diagnostic pop
-#endif
+#define ABSL_ANNOTATE_IGNORE_WRITES_BEGIN()  // empty
+#define ABSL_ANNOTATE_IGNORE_WRITES_END()    // empty
 
-/* Return non-zero value if running under valgrind.
-
-  If "valgrind.h" is included into dynamic_annotations.cc,
-  the regular valgrind mechanism will be used.
-  See http://valgrind.org/docs/manual/manual-core-adv.html about
-  RUNNING_ON_VALGRIND and other valgrind "client requests".
-  The file "valgrind.h" may be obtained by doing
-     svn co svn://svn.valgrind.org/valgrind/trunk/include
-
-  If for some reason you can't use "valgrind.h" or want to fake valgrind,
-  there are two ways to make this function return non-zero:
-    - Use environment variable: export RUNNING_ON_VALGRIND=1
-    - Make your tool intercept the function RunningOnValgrind() and
-      change its return value.
- */
-int RunningOnValgrind(void);
+#endif
 
-/* ValgrindSlowdown returns:
-    * 1.0, if (RunningOnValgrind() == 0)
-    * 50.0, if (RunningOnValgrind() != 0 && getenv("VALGRIND_SLOWDOWN") == NULL)
-    * atof(getenv("VALGRIND_SLOWDOWN")) otherwise
-   This function can be used to scale timeout values:
-   EXAMPLE:
-   for (;;) {
-     DoExpensiveBackgroundTask();
-     SleepForSeconds(5 * ValgrindSlowdown());
-   }
- */
-double ValgrindSlowdown(void);
+// -------------------------------------------------------------------------
+// Define the ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_* annotations using the more
+// primitive annotations defined above.
+//
+//     Instead of doing
+//        ABSL_ANNOTATE_IGNORE_READS_BEGIN();
+//        ... = x;
+//        ABSL_ANNOTATE_IGNORE_READS_END();
+//     one can use
+//        ... = ABSL_ANNOTATE_UNPROTECTED_READ(x);
+
+#if defined(ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED)
+
+// Start ignoring all memory accesses (both reads and writes).
+#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
+  do {                                                \
+    ABSL_ANNOTATE_IGNORE_READS_BEGIN();               \
+    ABSL_ANNOTATE_IGNORE_WRITES_BEGIN();              \
+  } while (0)
+
+// Stop ignoring both reads and writes.
+#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_END() \
+  do {                                              \
+    ABSL_ANNOTATE_IGNORE_WRITES_END();              \
+    ABSL_ANNOTATE_IGNORE_READS_END();               \
+  } while (0)
 
 #ifdef __cplusplus
-}
-#endif
+// ABSL_ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
+#define ABSL_ANNOTATE_UNPROTECTED_READ(x) \
+  absl::base_internal::AnnotateUnprotectedRead(x)
 
-/* ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace base_internal {
 
-     Instead of doing
-        ANNOTATE_IGNORE_READS_BEGIN();
-        ... = x;
-        ANNOTATE_IGNORE_READS_END();
-     one can use
-        ... = ANNOTATE_UNPROTECTED_READ(x); */
-#if defined(__cplusplus) && defined(ANNOTATIONS_ENABLED)
 template <typename T>
-inline T ANNOTATE_UNPROTECTED_READ(const volatile T &x) { /* NOLINT */
-  ANNOTATE_IGNORE_READS_BEGIN();
+inline T AnnotateUnprotectedRead(const volatile T& x) {  // NOLINT
+  ABSL_ANNOTATE_IGNORE_READS_BEGIN();
   T res = x;
-  ANNOTATE_IGNORE_READS_END();
+  ABSL_ANNOTATE_IGNORE_READS_END();
   return res;
-  }
+}
+
+}  // namespace base_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+#endif
+
 #else
-  #define ANNOTATE_UNPROTECTED_READ(x) (x)
+
+#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN()  // empty
+#define ABSL_ANNOTATE_IGNORE_READS_AND_WRITES_END()    // empty
+#define ABSL_ANNOTATE_UNPROTECTED_READ(x) (x)
+
 #endif
 
-#if DYNAMIC_ANNOTATIONS_ENABLED != 0 && defined(__cplusplus)
-  /* Apply ANNOTATE_BENIGN_RACE_SIZED to a static variable. */
-  #define ANNOTATE_BENIGN_RACE_STATIC(static_var, description)        \
-    namespace {                                                       \
-      class static_var ## _annotator {                                \
-       public:                                                        \
-        static_var ## _annotator() {                                  \
-          ANNOTATE_BENIGN_RACE_SIZED(&static_var,                     \
-                                      sizeof(static_var),             \
-            # static_var ": " description);                           \
-        }                                                             \
-      };                                                              \
-      static static_var ## _annotator the ## static_var ## _annotator;\
-    }  // namespace
-#else /* DYNAMIC_ANNOTATIONS_ENABLED == 0 */
-  #define ANNOTATE_BENIGN_RACE_STATIC(static_var, description)  /* empty */
-#endif /* DYNAMIC_ANNOTATIONS_ENABLED */
+ABSL_INTERNAL_BEGIN_EXTERN_C
+
+// -------------------------------------------------------------------------
+// Return non-zero value if running under valgrind.
+//
+//  If "valgrind.h" is included into dynamic_annotations.cc,
+//  the regular valgrind mechanism will be used.
+//  See http://valgrind.org/docs/manual/manual-core-adv.html about
+//  RUNNING_ON_VALGRIND and other valgrind "client requests".
+//  The file "valgrind.h" may be obtained by doing
+//     svn co svn://svn.valgrind.org/valgrind/trunk/include
+//
+//  If for some reason you can't use "valgrind.h" or want to fake valgrind,
+//  there are two ways to make this function return non-zero:
+//    - Use environment variable: export RUNNING_ON_VALGRIND=1
+//    - Make your tool intercept the function RunningOnValgrind() and
+//      change its return value.
+//
+int RunningOnValgrind(void);
+
+// ValgrindSlowdown returns:
+//    * 1.0, if (RunningOnValgrind() == 0)
+//    * 50.0, if (RunningOnValgrind() != 0 && getenv("VALGRIND_SLOWDOWN") ==
+//    NULL)
+//    * atof(getenv("VALGRIND_SLOWDOWN")) otherwise
+//   This function can be used to scale timeout values:
+//   EXAMPLE:
+//   for (;;) {
+//     DoExpensiveBackgroundTask();
+//     SleepForSeconds(5 * ValgrindSlowdown());
+//   }
+//
+double ValgrindSlowdown(void);
+
+ABSL_INTERNAL_END_EXTERN_C
+
+// -------------------------------------------------------------------------
+// Address sanitizer annotations
 
 #ifdef ADDRESS_SANITIZER
-/* Describe the current state of a contiguous container such as e.g.
- * std::vector or std::string. For more details see
- * sanitizer/common_interface_defs.h, which is provided by the compiler. */
+// Describe the current state of a contiguous container such as e.g.
+// std::vector or std::string. For more details see
+// sanitizer/common_interface_defs.h, which is provided by the compiler.
 #include <sanitizer/common_interface_defs.h>
-#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) \
+
+#define ABSL_ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) \
   __sanitizer_annotate_contiguous_container(beg, end, old_mid, new_mid)
-#define ADDRESS_SANITIZER_REDZONE(name)         \
-  struct { char x[8] __attribute__ ((aligned (8))); } name
+#define ABSL_ADDRESS_SANITIZER_REDZONE(name) \
+  struct {                                   \
+    char x[8] __attribute__((aligned(8)));   \
+  } name
+
 #else
-#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
-#define ADDRESS_SANITIZER_REDZONE(name) static_assert(true, "")
+
+#define ABSL_ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
+#define ABSL_ADDRESS_SANITIZER_REDZONE(name) static_assert(true, "")
+
 #endif  // ADDRESS_SANITIZER
 
-/* Undefine the macros intended only in this file. */
-#undef ANNOTALYSIS_ENABLED
-#undef ANNOTATIONS_ENABLED
-#undef ATTRIBUTE_IGNORE_READS_BEGIN
-#undef ATTRIBUTE_IGNORE_READS_END
+// -------------------------------------------------------------------------
+// Undefine the macros intended only for this file.
+
+#undef ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_ANNOTALYSIS_ENABLED
+#undef ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_BEGIN_EXTERN_C
+#undef ABSL_INTERNAL_END_EXTERN_C
+#undef ABSL_INTERNAL_STATIC_INLINE
 
-#endif  /* ABSL_BASE_DYNAMIC_ANNOTATIONS_H_ */
+#endif  // ABSL_BASE_DYNAMIC_ANNOTATIONS_H_
diff --git a/absl/base/internal/dynamic_annotations.h b/absl/base/internal/dynamic_annotations.h
new file mode 100644
index 00000000..7d80f41c
--- /dev/null
+++ b/absl/base/internal/dynamic_annotations.h
@@ -0,0 +1,403 @@
+// Copyright 2017 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.
+
+// This file defines dynamic annotations for use with dynamic analysis tool
+// such as valgrind, PIN, etc.
+//
+// Dynamic annotation is a source code annotation that affects the generated
+// code (that is, the annotation is not a comment). Each such annotation is
+// attached to a particular instruction and/or to a particular object (address)
+// in the program.
+//
+// The annotations that should be used by users are macros in all upper-case
+// (e.g., ANNOTATE_THREAD_NAME).
+//
+// Actual implementation of these macros may differ depending on the dynamic
+// analysis tool being used.
+//
+// This file supports the following configurations:
+// - Dynamic Annotations enabled (with static thread-safety warnings disabled).
+//   In this case, macros expand to functions implemented by Thread Sanitizer,
+//   when building with TSan. When not provided an external implementation,
+//   dynamic_annotations.cc provides no-op implementations.
+//
+// - Static Clang thread-safety warnings enabled.
+//   When building with a Clang compiler that supports thread-safety warnings,
+//   a subset of annotations can be statically-checked at compile-time. We
+//   expand these macros to static-inline functions that can be analyzed for
+//   thread-safety, but afterwards elided when building the final binary.
+//
+// - All annotations are disabled.
+//   If neither Dynamic Annotations nor Clang thread-safety warnings are
+//   enabled, then all annotation-macros expand to empty.
+
+#ifndef ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_
+#define ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_
+
+#include <stddef.h>
+
+#include "absl/base/config.h"
+
+// -------------------------------------------------------------------------
+// Decide which features are enabled
+
+#ifndef DYNAMIC_ANNOTATIONS_ENABLED
+#define DYNAMIC_ANNOTATIONS_ENABLED 0
+#endif
+
+#if defined(__clang__) && !defined(SWIG)
+#define ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED 1
+#else
+#define ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED 0
+#endif
+
+#if DYNAMIC_ANNOTATIONS_ENABLED != 0
+
+#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 1
+#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 1
+#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 1
+#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED 0
+#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED 1
+
+#else
+
+#define ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED 0
+#define ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED 0
+#define ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED 0
+
+// Clang provides limited support for static thread-safety analysis through a
+// feature called Annotalysis. We configure macro-definitions according to
+// whether Annotalysis support is available. When running in opt-mode, GCC
+// will issue a warning, if these attributes are compiled. Only include them
+// when compiling using Clang.
+
+// ANNOTALYSIS_ENABLED == 1 when IGNORE_READ_ATTRIBUTE_ENABLED == 1
+#define ABSL_INTERNAL_ANNOTALYSIS_ENABLED \
+  ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED
+// Read/write annotations are enabled in Annotalysis mode; disabled otherwise.
+#define ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED \
+  ABSL_INTERNAL_ANNOTALYSIS_ENABLED
+#endif
+
+// Memory annotations are also made available to LLVM's Memory Sanitizer
+#if defined(MEMORY_SANITIZER) && defined(__has_feature) && \
+    !defined(__native_client__)
+#if __has_feature(memory_sanitizer)
+#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 1
+#endif
+#endif
+
+#ifndef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
+#define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 0
+#endif
+
+#ifdef __cplusplus
+#define ABSL_INTERNAL_BEGIN_EXTERN_C extern "C" {
+#define ABSL_INTERNAL_END_EXTERN_C }  // extern "C"
+#define ABSL_INTERNAL_GLOBAL_SCOPED(F) ::F
+#define ABSL_INTERNAL_STATIC_INLINE inline
+#else
+#define ABSL_INTERNAL_BEGIN_EXTERN_C  // empty
+#define ABSL_INTERNAL_END_EXTERN_C    // empty
+#define ABSL_INTERNAL_GLOBAL_SCOPED(F) F
+#define ABSL_INTERNAL_STATIC_INLINE static inline
+#endif
+
+// -------------------------------------------------------------------------
+// Define race annotations.
+
+#if ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 1
+
+// -------------------------------------------------------------
+// Annotations that suppress errors. It is usually better to express the
+// program's synchronization using the other annotations, but these can be used
+// when all else fails.
+
+// Report that we may have a benign race at `pointer`, with size
+// "sizeof(*(pointer))". `pointer` must be a non-void* pointer. Insert at the
+// point where `pointer` has been allocated, preferably close to the point
+// where the race happens. See also ANNOTATE_BENIGN_RACE_STATIC.
+#define ANNOTATE_BENIGN_RACE(pointer, description)     \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized) \
+  (__FILE__, __LINE__, pointer, sizeof(*(pointer)), description)
+
+// Same as ANNOTATE_BENIGN_RACE(`address`, `description`), but applies to
+// the memory range [`address`, `address`+`size`).
+#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateBenignRaceSized)         \
+  (__FILE__, __LINE__, address, size, description)
+
+// Enable (`enable`!=0) or disable (`enable`==0) race detection for all threads.
+// This annotation could be useful if you want to skip expensive race analysis
+// during some period of program execution, e.g. during initialization.
+#define ANNOTATE_ENABLE_RACE_DETECTION(enable)             \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateEnableRaceDetection) \
+  (__FILE__, __LINE__, enable)
+
+// -------------------------------------------------------------
+// Annotations useful for debugging.
+
+// Report the current thread `name` to a race detector.
+#define ANNOTATE_THREAD_NAME(name) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateThreadName)(__FILE__, __LINE__, name)
+
+// -------------------------------------------------------------
+// Annotations useful when implementing locks. They are not normally needed by
+// modules that merely use locks. The `lock` argument is a pointer to the lock
+// object.
+
+// Report that a lock has been created at address `lock`.
+#define ANNOTATE_RWLOCK_CREATE(lock) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreate)(__FILE__, __LINE__, lock)
+
+// Report that a linker initialized lock has been created at address `lock`.
+#ifdef THREAD_SANITIZER
+#define ANNOTATE_RWLOCK_CREATE_STATIC(lock)               \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreateStatic) \
+  (__FILE__, __LINE__, lock)
+#else
+#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) ANNOTATE_RWLOCK_CREATE(lock)
+#endif
+
+// Report that the lock at address `lock` is about to be destroyed.
+#define ANNOTATE_RWLOCK_DESTROY(lock) \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockDestroy)(__FILE__, __LINE__, lock)
+
+// Report that the lock at address `lock` has been acquired.
+// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
+#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w)          \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockAcquired) \
+  (__FILE__, __LINE__, lock, is_w)
+
+// Report that the lock at address `lock` is about to be released.
+// `is_w`=1 for writer lock, `is_w`=0 for reader lock.
+#define ANNOTATE_RWLOCK_RELEASED(lock, is_w)          \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockReleased) \
+  (__FILE__, __LINE__, lock, is_w)
+
+// Apply ANNOTATE_BENIGN_RACE_SIZED to a static variable `static_var`.
+#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description)      \
+  namespace {                                                     \
+  class static_var##_annotator {                                  \
+   public:                                                        \
+    static_var##_annotator() {                                    \
+      ANNOTATE_BENIGN_RACE_SIZED(&static_var, sizeof(static_var), \
+                                 #static_var ": " description);   \
+    }                                                             \
+  };                                                              \
+  static static_var##_annotator the##static_var##_annotator;      \
+  }  // namespace
+
+#else  // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED == 0
+
+#define ANNOTATE_RWLOCK_CREATE(lock)                            // empty
+#define ANNOTATE_RWLOCK_CREATE_STATIC(lock)                     // empty
+#define ANNOTATE_RWLOCK_DESTROY(lock)                           // empty
+#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w)                    // empty
+#define ANNOTATE_RWLOCK_RELEASED(lock, is_w)                    // empty
+#define ANNOTATE_BENIGN_RACE(address, description)              // empty
+#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description)  // empty
+#define ANNOTATE_THREAD_NAME(name)                              // empty
+#define ANNOTATE_ENABLE_RACE_DETECTION(enable)                  // empty
+#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description)    // empty
+
+#endif  // ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
+
+// -------------------------------------------------------------------------
+// Define memory annotations.
+
+#if ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 1
+
+#include <sanitizer/msan_interface.h>
+
+#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
+  __msan_unpoison(address, size)
+
+#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
+  __msan_allocated_memory(address, size)
+
+#else  // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED == 0
+
+#if DYNAMIC_ANNOTATIONS_ENABLED == 1
+#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
+  do {                                                \
+    (void)(address);                                  \
+    (void)(size);                                     \
+  } while (0)
+#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) \
+  do {                                                  \
+    (void)(address);                                    \
+    (void)(size);                                       \
+  } while (0)
+#else
+#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size)    // empty
+#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size)  // empty
+#endif
+
+#endif  // ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
+
+// -------------------------------------------------------------------------
+// Define IGNORE_READS_BEGIN/_END attributes.
+
+#if ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED == 1
+
+#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE \
+  __attribute((exclusive_lock_function("*")))
+#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE \
+  __attribute((unlock_function("*")))
+
+#else  // ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED == 0
+
+#define ABSL_INTERNAL_IGNORE_READS_BEGIN_ATTRIBUTE  // empty
+#define ABSL_INTERNAL_IGNORE_READS_END_ATTRIBUTE    // empty
+
+#endif  // ABSL_INTERNAL_IGNORE_READS_ATTRIBUTE_ENABLED
+
+// -------------------------------------------------------------------------
+// Define IGNORE_READS_BEGIN/_END annotations.
+
+#if ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED == 1
+
+// Request the analysis tool to ignore all reads in the current thread until
+// ANNOTATE_IGNORE_READS_END is called. Useful to ignore intentional racey
+// reads, while still checking other reads and all writes.
+// See also ANNOTATE_UNPROTECTED_READ.
+#define ANNOTATE_IGNORE_READS_BEGIN() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsBegin)(__FILE__, __LINE__)
+
+// Stop ignoring reads.
+#define ANNOTATE_IGNORE_READS_END() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreReadsEnd)(__FILE__, __LINE__)
+
+#elif defined(ABSL_INTERNAL_ANNOTALYSIS_ENABLED)
+
+// When Annotalysis is enabled without Dynamic Annotations, the use of
+// static-inline functions allows the annotations to be read at compile-time,
+// while still letting the compiler elide the functions from the final build.
+//
+// TODO(delesley) -- The exclusive lock here ignores writes as well, but
+// allows IGNORE_READS_AND_WRITES to work properly.
+
+#define ANNOTATE_IGNORE_READS_BEGIN() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsBegin)()
+
+#define ANNOTATE_IGNORE_READS_END() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AbslInternalAnnotateIgnoreReadsEnd)()
+
+#else
+
+#define ANNOTATE_IGNORE_READS_BEGIN()  // empty
+#define ANNOTATE_IGNORE_READS_END()    // empty
+
+#endif
+
+// -------------------------------------------------------------------------
+// Define IGNORE_WRITES_BEGIN/_END annotations.
+
+#if ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED == 1
+
+// Similar to ANNOTATE_IGNORE_READS_BEGIN, but ignore writes instead.
+#define ANNOTATE_IGNORE_WRITES_BEGIN() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesBegin)(__FILE__, __LINE__)
+
+// Stop ignoring writes.
+#define ANNOTATE_IGNORE_WRITES_END() \
+  ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateIgnoreWritesEnd)(__FILE__, __LINE__)
+
+#else
+
+#define ANNOTATE_IGNORE_WRITES_BEGIN()  // empty
+#define ANNOTATE_IGNORE_WRITES_END()    // empty
+
+#endif
+
+// -------------------------------------------------------------------------
+// Define the ANNOTATE_IGNORE_READS_AND_WRITES_* annotations using the more
+// primitive annotations defined above.
+//
+//     Instead of doing
+//        ANNOTATE_IGNORE_READS_BEGIN();
+//        ... = x;
+//        ANNOTATE_IGNORE_READS_END();
+//     one can use
+//        ... = ANNOTATE_UNPROTECTED_READ(x);
+
+#if defined(ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED)
+
+// Start ignoring all memory accesses (both reads and writes).
+#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
+  do {                                           \
+    ANNOTATE_IGNORE_READS_BEGIN();               \
+    ANNOTATE_IGNORE_WRITES_BEGIN();              \
+  } while (0)
+
+// Stop ignoring both reads and writes.
+#define ANNOTATE_IGNORE_READS_AND_WRITES_END() \
+  do {                                         \
+    ANNOTATE_IGNORE_WRITES_END();              \
+    ANNOTATE_IGNORE_READS_END();               \
+  } while (0)
+
+#ifdef __cplusplus
+// ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
+#define ANNOTATE_UNPROTECTED_READ(x) \
+  absl::base_internal::AnnotateUnprotectedRead(x)
+
+#endif
+
+#else
+
+#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN()  // empty
+#define ANNOTATE_IGNORE_READS_AND_WRITES_END()    // empty
+#define ANNOTATE_UNPROTECTED_READ(x) (x)
+
+#endif
+
+// -------------------------------------------------------------------------
+// Address sanitizer annotations
+
+#ifdef ADDRESS_SANITIZER
+// Describe the current state of a contiguous container such as e.g.
+// std::vector or std::string. For more details see
+// sanitizer/common_interface_defs.h, which is provided by the compiler.
+#include <sanitizer/common_interface_defs.h>
+
+#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) \
+  __sanitizer_annotate_contiguous_container(beg, end, old_mid, new_mid)
+#define ADDRESS_SANITIZER_REDZONE(name)    \
+  struct {                                 \
+    char x[8] __attribute__((aligned(8))); \
+  } name
+
+#else
+
+#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
+#define ADDRESS_SANITIZER_REDZONE(name) static_assert(true, "")
+
+#endif  // ADDRESS_SANITIZER
+
+// -------------------------------------------------------------------------
+// Undefine the macros intended only for this file.
+
+#undef ABSL_INTERNAL_RACE_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_READS_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_WRITES_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_ANNOTALYSIS_ENABLED
+#undef ABSL_INTERNAL_READS_WRITES_ANNOTATIONS_ENABLED
+#undef ABSL_INTERNAL_BEGIN_EXTERN_C
+#undef ABSL_INTERNAL_END_EXTERN_C
+#undef ABSL_INTERNAL_STATIC_INLINE
+
+#endif  // ABSL_BASE_INTERNAL_DYNAMIC_ANNOTATIONS_H_