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authorAbseil Team <absl-team@google.com>2018-11-27T22·21-0800
committervslashg <gfalcon@google.com>2018-11-27T22·37-0500
commit13327debebc5c2d1d4991b69fe50450e340e50e4 (patch)
treef86952300b0ffc841819ded709ad05764dbafd8e /absl
parent3088e76c597e068479e82508b1770a7ad0c806b6 (diff)
Export of internal Abseil changes.
--
15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>:

Fix miscellaneous CMake change interleaving issues for the daily release:
  * add back the absl::container target
  * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt
  * Add trailing newline to the end of AbseilConfigureCopts.cmake

PiperOrigin-RevId: 223057096

--
baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>:

Internal Cleanup.

PiperOrigin-RevId: 223051579

--
6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>:

Internal Change.

PiperOrigin-RevId: 223046855

--
5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>:

Workaround for gcc bug https://gcc.gnu.org/PR88115

PiperOrigin-RevId: 223041901

--
36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>:

Clarify visit() constraints

PiperOrigin-RevId: 223032194

--
afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>:

Fix comment typos.

PiperOrigin-RevId: 223024090

--
e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>:

Make absl::spinlock_test_common TESTONLY

This should fix https://github.com/abseil/abseil-cpp/issues/221

PiperOrigin-RevId: 222885323

--
5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 222877017

--
96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>:

Align CMake and Bazel compile options.  This is the first step towards a single source of truth for Abseil compile options.  Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier.

PiperOrigin-RevId: 222858408

--
7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>:

Revert "absl: cap SpinLock backoff to 4ms"

PiperOrigin-RevId: 222656230

--
0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>:

Update absl/container/CMakeLists.txt to use new functions
i.e. absl_cc_(library|test)

PiperOrigin-RevId: 222535766

--
92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>:

Disable header parsing for broken targets

PiperOrigin-RevId: 222257218

--
39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>:

absl: cap SpinLock backoff to 4ms

The current backoff logic has 3 problems:
1. It can produce too high values (up to 256ms), which can negatively
affect tail latency. The value was chosen long time ago and now it's
a good idea to reconsider it.
2. It does not have low bound, so on any iteration it can produce
a very small value that will lead to unnecessary cpu consumption.
3. It does not increase low bound with the number of iterations.
So if the SpinLock is actually somehow locked for a very prolonged time,
a waiter can still wake periodically.

Rework the logic to solve these problems.
Add lower bound of 128us, no code should rely on absence of episodic
delays in this range as they can occur everywhere.
Lower upper bound to 4ms. A thread sleeping for 4ms does not consume
significant cpu time (see below).
Grow lower bound with the number of iterations.

This is cpu consumption of a process doing usleep(x) in a loop
(sampled with ps):

    64us -> 4.0%
   128us -> 2.7%
   256us -> 3.5%
   512us -> 2.8%
  1024us -> 1.6%
  2048us -> 0.6%
  4096us -> 0.3%
  8192us -> 0.0%

Few millisecond sleeps do not consume significant time.

PiperOrigin-RevId: 222196086

--
17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>:

Add benchmarks for hashing civil_times.

PiperOrigin-RevId: 222152108
GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe
Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
Diffstat (limited to 'absl')
-rw-r--r--absl/algorithm/CMakeLists.txt4
-rw-r--r--absl/base/CMakeLists.txt24
-rw-r--r--absl/container/CMakeLists.txt754
-rw-r--r--absl/container/internal/hash_policy_testing.h6
-rw-r--r--absl/container/internal/layout.h18
-rw-r--r--absl/container/internal/layout_test.cc33
-rw-r--r--absl/copts.bzl2
-rw-r--r--absl/hash/CMakeLists.txt30
-rw-r--r--absl/strings/CMakeLists.txt2
-rw-r--r--absl/time/BUILD.bazel1
-rw-r--r--absl/time/civil_time_benchmark.cc64
-rw-r--r--absl/time/internal/cctz/BUILD.bazel2
-rw-r--r--absl/time/time.h3
-rw-r--r--absl/types/CMakeLists.txt4
-rw-r--r--absl/types/variant.h7
15 files changed, 793 insertions, 161 deletions
diff --git a/absl/algorithm/CMakeLists.txt b/absl/algorithm/CMakeLists.txt
index 6608f184cdaf..87a165c06a31 100644
--- a/absl/algorithm/CMakeLists.txt
+++ b/absl/algorithm/CMakeLists.txt
@@ -19,6 +19,8 @@ absl_cc_library(
     algorithm
   HDRS
     "algorithm.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   PUBLIC
 )
 
@@ -37,6 +39,8 @@ absl_cc_library(
     algorithm_container
   HDRS
     "container.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEPS
     absl::algorithm
     absl::core_headers
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 04dbf39e1160..212dd0836284 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -36,6 +36,8 @@ absl_cc_library(
   HDRS
     "config.h"
     "policy_checks.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   PUBLIC
 )
 
@@ -46,6 +48,8 @@ absl_cc_library(
     "dynamic_annotations.h"
   SRCS
     "dynamic_annotations.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEFINES
     "__CLANG_SUPPORT_DYN_ANNOTATION__"
   PUBLIC
@@ -60,6 +64,8 @@ absl_cc_library(
     "optimization.h"
     "port.h"
     "thread_annotations.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEPS
     absl::config
   PUBLIC
@@ -73,6 +79,8 @@ absl_cc_library(
     "internal/low_level_alloc.h"
   SRCS
     "internal/low_level_alloc.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEPS
     absl::base
     absl::config
@@ -89,6 +97,8 @@ absl_cc_library(
     "internal/identity.h"
     "internal/inline_variable.h"
     "internal/invoke.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
 )
 
 absl_cc_library(
@@ -115,6 +125,8 @@ absl_cc_library(
     "internal/sysinfo.cc"
     "internal/thread_identity.cc"
     "internal/unscaledcycleclock.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEPS
     absl::base_internal
     absl::config
@@ -132,6 +144,7 @@ absl_cc_library(
   SRCS
     "internal/throw_delegate.cc"
   COPTS
+    ${ABSL_DEFAULT_COPTS}
     ${ABSL_EXCEPTIONS_FLAG}
   DEPS
     absl::base
@@ -142,6 +155,8 @@ absl_cc_library(
     exception_testing
   HDRS
     "internal/exception_testing.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEPS
     absl::config
     gtest
@@ -153,6 +168,8 @@ absl_cc_library(
     pretty_function
   HDRS
     "internal/pretty_function.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
 )
 
 absl_cc_library(
@@ -163,6 +180,7 @@ absl_cc_library(
   SRCS
     "internal/exception_safety_testing.cc"
   COPTS
+    ${ABSL_DEFAULT_COPTS}
     ${ABSL_EXCEPTIONS_FLAG}
   DEPS
     absl::base
@@ -263,7 +281,7 @@ absl_cc_library(
     absl::spinlock_wait
     absl::synchronization
     gtest
-  PUBLIC
+  TESTONLY
 )
 
 # On bazel BUILD this target use "alwayslink = 1" which is not implemented here
@@ -286,6 +304,8 @@ absl_cc_library(
   HDRS
     "internal/endian.h"
     "internal/unaligned_access.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEPS
     absl::config
     absl::core_headers
@@ -377,6 +397,8 @@ absl_cc_library(
     bits
   HDRS
     "internal/bits.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
   DEPS
     absl::core_headers
 )
diff --git a/absl/container/CMakeLists.txt b/absl/container/CMakeLists.txt
index 72113e195127..7cddd84bd693 100644
--- a/absl/container/CMakeLists.txt
+++ b/absl/container/CMakeLists.txt
@@ -14,164 +14,674 @@
 # limitations under the License.
 #
 
-
-list(APPEND CONTAINER_PUBLIC_HEADERS
-  "fixed_array.h"
-  "flat_hash_map.h"
-  "flat_hash_set.h"
-  "inlined_vector.h"
-  "node_hash_map.h"
-  "node_hash_set.h"
-)
-
-
-list(APPEND CONTAINER_INTERNAL_HEADERS
-  "internal/compressed_tuple.h"
-  "internal/container_memory.h"
-  "internal/hash_function_defaults.h"
-  "internal/hash_generator_testing.h"
-  "internal/hash_policy_testing.h"
-  "internal/hash_policy_traits.h"
-  "internal/hashtable_debug.h"
-  "internal/layout.h"
-  "internal/node_hash_policy.h"
-  "internal/raw_hash_map.h"
-  "internal/raw_hash_set.h"
-  "internal/test_instance_tracker.h"
-  "internal/tracked.h"
-  "internal/unordered_map_constructor_test.h"
-  "internal/unordered_map_lookup_test.h"
-  "internal/unordered_map_modifiers_test.h"
-  "internal/unordered_set_constructor_test.h"
-  "internal/unordered_set_lookup_test.h"
-  "internal/unordered_set_modifiers_test.h"
-)
-
-
-absl_library(
-  TARGET
-    absl_container
-  SOURCES
-   "internal/raw_hash_set.cc"
-  EXPORT_NAME
+# This is deprecated and will be removed in the future.  It also doesn't do
+# anything anyways.  Prefer to use the library associated with the API you are
+# using.
+absl_cc_library(
+  NAME
     container
+  SRCS
+    "internal/raw_hash_set.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  PUBLIC
 )
 
-#
-## TESTS
-#
+absl_cc_library(
+  NAME
+    compressed_tuple
+  SRCS
+   "internal/compressed_tuple.h"
+  DEPS
+    absl::utility
+  PUBLIC
+)
 
-list(APPEND TEST_INSTANCE_TRACKER_LIB_SRC
-  "internal/test_instance_tracker.cc"
-  ${CONTAINER_PUBLIC_HEADERS}
-  ${CONTAINER_INTERNAL_HEADERS}
+absl_cc_test(
+  NAME
+    compressed_tuple_test
+  SRCS
+    "internal/compressed_tuple_test.cc"
+  DEPS
+    absl::compressed_tuple
+    gmock_main
 )
 
+absl_cc_library(
+  NAME
+    fixed_array
+  HDRS
+   "fixed_array.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::compressed_tuple
+    absl::algorithm
+    absl::core_headers
+    absl::dynamic_annotations
+    absl::throw_delegate
+    absl::memory
+  PUBLIC
+)
 
-absl_library(
-  TARGET
-    test_instance_tracker_lib
-  SOURCES
-    ${TEST_INSTANCE_TRACKER_LIB_SRC}
-  PUBLIC_LIBRARIES
-    absl::container
+absl_cc_test(
+  NAME
+    fixed_array_test
+  SRCS
+    "fixed_array_test.cc"
+  COPTS
+    ${ABSL_EXCEPTIONS_FLAG}
+  LINKOPTS
+    ${ABSL_EXCEPTIONS_FLAG_LINKOPTS}
+  DEPS
+    absl::fixed_array
+    absl::exception_testing
+    absl::hash_testing
+    absl::memory
+    gmock_main
 )
 
+absl_cc_test(
+  NAME
+    fixed_array_test_noexceptions
+  SRCS
+    "fixed_array_test.cc"
+  DEPS
+    absl::fixed_array
+    absl::exception_testing
+    absl::hash_testing
+    absl::memory
+    gmock_main
+)
 
+absl_cc_test(
+  NAME
+    fixed_array_exception_safety_test
+  SRCS
+    "fixed_array_exception_safety_test.cc"
+  COPTS
+    ${ABSL_EXCEPTIONS_FLAG}
+  LINKOPTS
+    ${ABSL_EXCEPTIONS_FLAG_LINKOPTS}
+  DEPS
+    absl::fixed_array
+    absl::exception_safety_testing
+    gmock_main
+)
 
-# test fixed_array_test
-set(FIXED_ARRAY_TEST_SRC "fixed_array_test.cc")
-set(FIXED_ARRAY_TEST_PUBLIC_LIBRARIES absl::base absl_internal_throw_delegate test_instance_tracker_lib)
+absl_cc_library(
+  NAME
+    inlined_vector
+  HDRS
+   "inlined_vector.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::algorithm
+    absl::core_headers
+    absl::throw_delegate
+    absl::memory
+  PUBLIC
+)
 
-absl_test(
-  TARGET
-    fixed_array_test
-  SOURCES
-    ${FIXED_ARRAY_TEST_SRC}
-  PUBLIC_LIBRARIES
-    ${FIXED_ARRAY_TEST_PUBLIC_LIBRARIES}
-  PRIVATE_COMPILE_FLAGS
+absl_cc_test(
+  NAME
+    inlined_vector_test
+  SRCS
+    "inlined_vector_test.cc"
+  COPTS
     ${ABSL_EXCEPTIONS_FLAG}
+  LINKOPTS
+    ${ABSL_EXCEPTIONS_FLAG_LINKOPTS}
+  DEPS
+    absl::inlined_vector
+    absl::test_instance_tracker
+    absl::base
+    absl::core_headers
+    absl::exception_testing
+    absl::hash_testing
+    absl::memory
+    absl::strings
+    gmock_main
 )
 
+absl_cc_test(
+  NAME
+    inlined_vector_test_noexceptions
+  SRCS
+    "inlined_vector_test.cc"
+  DEPS
+    absl::inlined_vector
+    absl::test_instance_tracker
+    absl::base
+    absl::core_headers
+    absl::exception_testing
+    absl::hash_testing
+    absl::memory
+    absl::strings
+    gmock_main
+)
 
+absl_cc_library(
+  NAME
+    test_instance_tracker
+  HDRS
+    "internal/test_instance_tracker.h"
+  SRCS
+    "internal/test_instance_tracker.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  TESTONLY
+)
 
-absl_test(
-  TARGET
-    fixed_array_test_noexceptions
-  SOURCES
-    ${FIXED_ARRAY_TEST_SRC}
-  PUBLIC_LIBRARIES
-    ${FIXED_ARRAY_TEST_PUBLIC_LIBRARIES}
+absl_cc_test(
+  NAME
+    test_instance_tracker_test
+  SRCS
+    "internal/test_instance_tracker_test.cc"
+  DEPS
+    absl::test_instance_tracker
+    gmock_main
 )
 
+absl_cc_library(
+  NAME
+    flat_hash_map
+  HDRS
+    "flat_hash_map.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::container_memory
+    absl::hash_function_defaults
+    absl::raw_hash_map
+    absl::algorithm_container
+    absl::memory
+  PUBLIC
+)
 
-# test fixed_array_exception_safety_test
-set(FIXED_ARRAY_EXCEPTION_SAFETY_TEST_SRC "fixed_array_exception_safety_test.cc")
-set(FIXED_ARRAY_EXCEPTION_SAFETY_TEST_PUBLIC_LIBRARIES
-  absl::container
-  absl_internal_exception_safety_testing
+absl_cc_test(
+  NAME
+    flat_hash_map_test
+  SRCS
+    "flat_hash_map_test.cc"
+  COPTS
+    "-DUNORDERED_MAP_CXX17"
+  DEPS
+    absl::flat_hash_map
+    absl::hash_generator_testing
+    absl::unordered_map_constructor_test
+    absl::unordered_map_lookup_test
+    absl::unordered_map_modifiers_test
+    absl::any
+    gmock_main
 )
 
-absl_test(
-  TARGET
-    fixed_array_exception_safety_test
-  SOURCES
-    ${FIXED_ARRAY_EXCEPTION_SAFETY_TEST_SRC}
-  PUBLIC_LIBRARIES
-    ${FIXED_ARRAY_EXCEPTION_SAFETY_TEST_PUBLIC_LIBRARIES}
-  PRIVATE_COMPILE_FLAGS
-    ${ABSL_EXCEPTIONS_FLAG}
+absl_cc_library(
+  NAME
+    flat_hash_set
+  HDRS
+    "flat_hash_set.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::container_memory
+    absl::hash_function_defaults
+    absl::raw_hash_set
+    absl::algorithm_container
+    absl::core_headers
+    absl::memory
+  PUBLIC
 )
 
+absl_cc_test(
+  NAME
+    flat_hash_set_test
+  SRCS
+    "flat_hash_set_test.cc"
+  COPTS
+    "-DUNORDERED_SET_CXX17"
+  DEPS
+    absl::flat_hash_set
+    absl::hash_generator_testing
+    absl::unordered_set_constructor_test
+    absl::unordered_set_lookup_test
+    absl::unordered_set_modifiers_test
+    absl::memory
+    absl::strings
+    gmock_main
+)
 
-# test inlined_vector_test
-set(INLINED_VECTOR_TEST_SRC "inlined_vector_test.cc")
-set(INLINED_VECTOR_TEST_PUBLIC_LIBRARIES absl::base absl_internal_throw_delegate test_instance_tracker_lib)
+absl_cc_library(
+  NAME
+    node_hash_map
+  HDRS
+    "node_hash_map.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::container_memory
+    absl::hash_function_defaults
+    absl::node_hash_policy
+    absl::raw_hash_map
+    absl::algorithm_container
+    absl::memory
+  PUBLIC
+)
 
-absl_test(
-  TARGET
-    inlined_vector_test
-  SOURCES
-    ${INLINED_VECTOR_TEST_SRC}
-  PUBLIC_LIBRARIES
-    ${INLINED_VECTOR_TEST_PUBLIC_LIBRARIES}
+absl_cc_test(
+  NAME
+    node_hash_map_test
+  SRCS
+    "node_hash_map_test.cc"
+  COPTS
+    "-DUNORDERED_MAP_CXX17"
+  DEPS
+    absl::hash_generator_testing
+    absl::node_hash_map
+    absl::tracked
+    absl::unordered_map_constructor_test
+    absl::unordered_map_lookup_test
+    absl::unordered_map_modifiers_test
+    gmock_main
 )
 
-absl_test(
-  TARGET
-    inlined_vector_test_noexceptions
-  SOURCES
-    ${INLINED_VECTOR_TEST_SRC}
-  PUBLIC_LIBRARIES
-    ${INLINED_VECTOR_TEST_PUBLIC_LIBRARIES}
-  PRIVATE_COMPILE_FLAGS
-    ${ABSL_NOEXCEPTION_CXXFLAGS}
+absl_cc_library(
+  NAME
+    node_hash_set
+  HDRS
+    "node_hash_set.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::hash_function_defaults
+    absl::node_hash_policy
+    absl::raw_hash_set
+    absl::algorithm_container
+    absl::memory
+  PUBLIC
 )
 
+absl_cc_test(
+  NAME
+    node_hash_set_test
+  SRCS
+    "node_hash_set_test.cc"
+  COPTS
+    "-DUNORDERED_SET_CXX17"
+  DEPS
+    absl::hash_generator_testing
+    absl::node_hash_set
+    absl::unordered_set_constructor_test
+    absl::unordered_set_lookup_test
+    absl::unordered_set_modifiers_test
+    gmock_main
+)
 
-# test test_instance_tracker_test
-set(TEST_INSTANCE_TRACKER_TEST_SRC "internal/test_instance_tracker_test.cc")
-set(TEST_INSTANCE_TRACKER_TEST_PUBLIC_LIBRARIES absl::base absl_internal_throw_delegate test_instance_tracker_lib)
+absl_cc_library(
+  NAME
+    container_memory
+  HDRS
+    "internal/container_memory.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::memory
+    absl::utility
+  PUBLIC
+)
 
+absl_cc_test(
+  NAME
+    container_memory_test
+  SRCS
+    "internal/container_memory_test.cc"
+  DEPS
+    absl::container_memory
+    absl::strings
+    gmock_main
+)
 
-absl_test(
-  TARGET
-    test_instance_tracker_test
-  SOURCES
-    ${TEST_INSTANCE_TRACKER_TEST_SRC}
-  PUBLIC_LIBRARIES
-    ${TEST_INSTANCE_TRACKER_TEST_PUBLIC_LIBRARIES}
+absl_cc_library(
+  NAME
+    hash_function_defaults
+  HDRS
+    "internal/hash_function_defaults.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
+    absl::hash
+    absl::strings
+  PUBLIC
+)
+
+absl_cc_test(
+  NAME
+    hash_function_defaults_test
+  SRCS
+    "internal/hash_function_defaults_test.cc"
+  DEPS
+    absl::hash_function_defaults
+    absl::hash
+    absl::strings
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    hash_generator_testing
+  HDRS
+    "internal/hash_generator_testing.h"
+  SRCS
+    "internal/hash_generator_testing.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash_policy_testing
+    absl::meta
+    absl::strings
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    hash_policy_testing
+  HDRS
+    "internal/hash_policy_testing.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash
+    absl::strings
+  TESTONLY
+)
+
+absl_cc_test(
+  NAME
+    hash_policy_testing_test
+  SRCS
+    "internal/hash_policy_testing_test.cc"
+  DEPS
+    absl::hash_policy_testing
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    hash_policy_traits
+  HDRS
+    "internal/hash_policy_traits.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::meta
+  PUBLIC
+)
+
+absl_cc_test(
+  NAME
+    hash_policy_traits_test
+  SRCS
+    "internal/hash_policy_traits_test.cc"
+  DEPS
+    absl::hash_policy_traits
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    hashtable_debug
+  HDRS
+    "internal/hashtable_debug.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::hashtable_debug_hooks
+)
+
+absl_cc_library(
+  NAME
+    hashtable_debug_hooks
+  HDRS
+    "internal/hashtable_debug_hooks.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  PUBLIC
+)
+
+absl_cc_library(
+  NAME
+    node_hash_policy
+  HDRS
+    "internal/node_hash_policy.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  PUBLIC
 )
 
-absl_test(
-  TARGET
+absl_cc_test(
+  NAME
+    node_hash_policy_test
+  SRCS
+    "internal/node_hash_policy_test.cc"
+  DEPS
+    absl::hash_policy_traits
+    absl::node_hash_policy
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    raw_hash_map
+  HDRS
+    "internal/raw_hash_map.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::container_memory
+    absl::raw_hash_set
+  PUBLIC
+)
+
+absl_cc_library(
+  NAME
+    raw_hash_set
+  HDRS
+    "internal/raw_hash_set.h"
+  SRCS
+    "internal/raw_hash_set.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::compressed_tuple
+    absl::container_memory
+    absl::hash_policy_traits
+    absl::hashtable_debug_hooks
+    absl::layout
+    absl::bits
+    absl::config
+    absl::core_headers
+    absl::endian
+    absl::memory
+    absl::meta
+    absl::optional
+    absl::utility
+  PUBLIC
+)
+
+absl_cc_test(
+  NAME
     raw_hash_set_test
-  SOURCES
+  SRCS
     "internal/raw_hash_set_test.cc"
-  PUBLIC_LIBRARIES
+  DEPS
+    absl::container_memory
+    absl::hash_function_defaults
+    absl::hash_policy_testing
+    absl::hashtable_debug
+    absl::raw_hash_set
     absl::base
-    absl::hash
-    absl_internal_throw_delegate
-    test_instance_tracker_lib
+    absl::core_headers
+    absl::strings
+    gmock_main
+)
+
+absl_cc_test(
+  NAME
+    raw_hash_set_allocator_test
+  SRCS
+    "internal/raw_hash_set_allocator_test.cc"
+  DEPS
+    absl::raw_hash_set
+    absl::tracked
+    absl::core_headers
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    layout
+  HDRS
+    "internal/layout.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::core_headers
+    absl::meta
+    absl::strings
+    absl::span
+    absl::utility
+  PUBLIC
+)
+
+absl_cc_test(
+  NAME
+    layout_test
+  SRCS
+    "internal/layout_test.cc"
+  DEPS
+    absl::layout
+    absl::base
+    absl::core_headers
+    absl::span
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    tracked
+  HDRS
+    "internal/tracked.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    unordered_map_constructor_test
+  HDRS
+    "internal/unordered_map_constructor_test.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash_generator_testing
+    absl::hash_policy_testing
+    gmock
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    unordered_map_lookup_test
+  HDRS
+    "internal/unordered_map_lookup_test.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash_generator_testing
+    absl::hash_policy_testing
+    gmock
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    unordered_map_modifiers_test
+  HDRS
+    "internal/unordered_map_modifiers_test.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash_generator_testing
+    absl::hash_policy_testing
+    gmock
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    unordered_set_constructor_test
+  HDRS
+    "internal/unordered_set_constructor_test.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash_generator_testing
+    absl::hash_policy_testing
+    gmock
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    unordered_set_lookup_test
+  HDRS
+    "internal/unordered_set_lookup_test.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash_generator_testing
+    absl::hash_policy_testing
+    gmock
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    unordered_set_modifiers_test
+  HDRS
+    "internal/unordered_set_modifiers_test.h"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::hash_generator_testing
+    absl::hash_policy_testing
+    gmock
+  TESTONLY
+)
+
+absl_cc_test(
+  NAME
+    unordered_set_test
+  SRCS
+    "internal/unordered_set_test.cc"
+  DEPS
+    absl::unordered_set_constructor_test
+    absl::unordered_set_lookup_test
+    absl::unordered_set_modifiers_test
+    gmock_main
+)
+
+absl_cc_test(
+  NAME
+    unordered_map_test
+  SRCS
+    "internal/unordered_map_test.cc"
+  DEPS
+    absl::unordered_map_constructor_test
+    absl::unordered_map_lookup_test
+    absl::unordered_map_modifiers_test
+    gmock_main
 )
diff --git a/absl/container/internal/hash_policy_testing.h b/absl/container/internal/hash_policy_testing.h
index 38bbec77a2ed..7fb819a74d23 100644
--- a/absl/container/internal/hash_policy_testing.h
+++ b/absl/container/internal/hash_policy_testing.h
@@ -169,7 +169,11 @@ auto keys(const Set& s)
 // take allocator arguments. This test is defined ad-hoc for the platforms
 // we care about (notably Crosstool 17) because libstdcxx's useless
 // versioning scheme precludes a more principled solution.
-#if defined(__GLIBCXX__) && __GLIBCXX__ <= 20140425
+// From GCC-4.9 Changelog: (src: https://gcc.gnu.org/gcc-4.9/changes.html)
+// "the unordered associative containers in <unordered_map> and <unordered_set>
+// meet the allocator-aware container requirements;"
+#if (defined(__GLIBCXX__) && __GLIBCXX__ <= 20140425 ) || \
+( __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 9 ))
 #define ABSL_UNORDERED_SUPPORTS_ALLOC_CTORS 0
 #else
 #define ABSL_UNORDERED_SUPPORTS_ALLOC_CTORS 1
diff --git a/absl/container/internal/layout.h b/absl/container/internal/layout.h
index 676c7d67ee68..a9c1244a4e79 100644
--- a/absl/container/internal/layout.h
+++ b/absl/container/internal/layout.h
@@ -232,13 +232,17 @@ struct SizeOf : NotAligned<T>, std::integral_constant<size_t, sizeof(T)> {};
 template <class T, size_t N>
 struct SizeOf<Aligned<T, N>> : std::integral_constant<size_t, sizeof(T)> {};
 
+// Note: workaround for https://gcc.gnu.org/PR88115
 template <class T>
-struct AlignOf : NotAligned<T>, std::integral_constant<size_t, alignof(T)> {};
+struct AlignOf : NotAligned<T> {
+  static constexpr size_t value = alignof(T);
+};
 
 template <class T, size_t N>
-struct AlignOf<Aligned<T, N>> : std::integral_constant<size_t, N> {
+struct AlignOf<Aligned<T, N>> {
   static_assert(N % alignof(T) == 0,
                 "Custom alignment can't be lower than the type's alignment");
+  static constexpr size_t value = N;
 };
 
 // Does `Ts...` contain `T`?
@@ -290,7 +294,7 @@ std::string TypeName() {
 #ifdef ABSL_INTERNAL_HAS_CXA_DEMANGLE
   demangled = abi::__cxa_demangle(typeid(T).name(), nullptr, nullptr, &status);
 #endif
-  if (status == 0 && demangled != nullptr) {  // Demangling succeeeded.
+  if (status == 0 && demangled != nullptr) {  // Demangling succeeded.
     absl::StrAppend(&out, "<", demangled, ">");
     free(demangled);
   } else {
@@ -396,7 +400,7 @@ class LayoutImpl<std::tuple<Elements...>, absl::index_sequence<SizeSeq...>,
     static_assert(N < NumOffsets, "Index out of bounds");
     return adl_barrier::Align(
         Offset<N - 1>() + SizeOf<ElementType<N - 1>>() * size_[N - 1],
-        ElementAlignment<N>());
+        ElementAlignment<N>::value);
   }
 
   // Offset in bytes of the array with the specified element type. There must
@@ -445,7 +449,7 @@ class LayoutImpl<std::tuple<Elements...>, absl::index_sequence<SizeSeq...>,
     return Size<ElementIndex<T>()>();
   }
 
-    // The number of elements of all arrays for which they are known.
+  // The number of elements of all arrays for which they are known.
   constexpr std::array<size_t, NumSizes> Sizes() const {
     return {{Size<SizeSeq>()...}};
   }
@@ -610,7 +614,7 @@ class LayoutImpl<std::tuple<Elements...>, absl::index_sequence<SizeSeq...>,
 #ifdef ADDRESS_SANITIZER
     PoisonPadding<Char, N - 1>(p);
     // The `if` is an optimization. It doesn't affect the observable behaviour.
-    if (ElementAlignment<N - 1>() % ElementAlignment<N>()) {
+    if (ElementAlignment<N - 1>::value % ElementAlignment<N>::value) {
       size_t start =
           Offset<N - 1>() + SizeOf<ElementType<N - 1>>() * size_[N - 1];
       ASAN_POISON_MEMORY_REGION(p + start, Offset<N>() - start);
@@ -690,7 +694,7 @@ class Layout : public internal_layout::LayoutType<sizeof...(Ts), Ts...> {
   //
   // It's allowed to pass fewer array sizes than the number of arrays. E.g.,
   // if all you need is to the offset of the second array, you only need to
-  // pass one argument -- the number of elements in the first arrays.
+  // pass one argument -- the number of elements in the first array.
   //
   //   // int[3] followed by 4 bytes of padding and an unknown number of
   //   // doubles.
diff --git a/absl/container/internal/layout_test.cc b/absl/container/internal/layout_test.cc
index f35157a3bd85..224f741a7879 100644
--- a/absl/container/internal/layout_test.cc
+++ b/absl/container/internal/layout_test.cc
@@ -45,7 +45,17 @@ Expected Type(Actual val) {
   return val;
 }
 
-using Int128 = int64_t[2];
+// Helper class to test different size and alignments.
+struct alignas(8) Int128 {
+  uint64_t a, b;
+  friend bool operator==(Int128 lhs, Int128 rhs) {
+    return std::tie(lhs.a, lhs.b) == std::tie(rhs.a, rhs.b);
+  }
+
+  static std::string Name() {
+    return internal_layout::adl_barrier::TypeName<Int128>();
+  }
+};
 
 // Properties of types that this test relies on.
 static_assert(sizeof(int8_t) == 1, "");
@@ -1361,12 +1371,6 @@ TEST(Layout, PoisonPadding) {
 }
 
 TEST(Layout, DebugString) {
-  const std::string int64_type =
-#ifdef _MSC_VER
-  "__int64";
-#else   // _MSC_VER
-  std::is_same<int64_t, long long>::value ? "long long" : "long";  // NOLINT
-#endif  // _MSC_VER
   {
     constexpr auto x = Layout<int8_t, int32_t, int8_t, Int128>::Partial();
     EXPECT_EQ("@0<signed char>(1)", x.DebugString());
@@ -1384,24 +1388,24 @@ TEST(Layout, DebugString) {
     constexpr auto x = Layout<int8_t, int32_t, int8_t, Int128>::Partial(1, 2, 3);
     EXPECT_EQ(
         "@0<signed char>(1)[1]; @4<int>(4)[2]; @12<signed char>(1)[3]; "
-        "@16<" +
-            int64_type + " [2]>(16)",
+        "@16" +
+            Int128::Name() + "(16)",
         x.DebugString());
   }
   {
     constexpr auto x = Layout<int8_t, int32_t, int8_t, Int128>::Partial(1, 2, 3, 4);
     EXPECT_EQ(
         "@0<signed char>(1)[1]; @4<int>(4)[2]; @12<signed char>(1)[3]; "
-        "@16<" +
-            int64_type + " [2]>(16)[4]",
+        "@16" +
+            Int128::Name() + "(16)[4]",
         x.DebugString());
   }
   {
     constexpr Layout<int8_t, int32_t, int8_t, Int128> x(1, 2, 3, 4);
     EXPECT_EQ(
         "@0<signed char>(1)[1]; @4<int>(4)[2]; @12<signed char>(1)[3]; "
-        "@16<" +
-            int64_type + " [2]>(16)[4]",
+        "@16" +
+            Int128::Name() + "(16)[4]",
         x.DebugString());
   }
 }
@@ -1528,8 +1532,7 @@ class CompactString {
   const char* c_str() const {
     // Equivalent to reinterpret_cast<char*>(p.get() + sizeof(size_t)).
     // The argument in Partial(1) specifies that we have size_t[1] in front of
-    // the
-    // characters.
+    // the characters.
     return L::Partial(1).Pointer<char>(p_.get());
   }
 
diff --git a/absl/copts.bzl b/absl/copts.bzl
index 49bb697d6e5b..49c4c9e0b7de 100644
--- a/absl/copts.bzl
+++ b/absl/copts.bzl
@@ -3,6 +3,8 @@
 Flags specified here must not impact ABI. Code compiled with and without these
 opts will be linked together, and in some cases headers compiled with and
 without these options will be part of the same program.
+
+DO NOT CHANGE THIS FILE WITHOUT CHANGING THE SAME FLAG IN absl/CMake/AbseilConfigureCopts.cmake!!
 """
 GCC_FLAGS = [
     "-Wall",
diff --git a/absl/hash/CMakeLists.txt b/absl/hash/CMakeLists.txt
index 474092f0f72a..a0d59b0bd4d3 100644
--- a/absl/hash/CMakeLists.txt
+++ b/absl/hash/CMakeLists.txt
@@ -31,7 +31,7 @@ list(APPEND HASH_SRC
   ${HASH_INTERNAL_HEADERS}
 )
 
-set(HASH_PUBLIC_LIBRARIES absl::hash absl::container absl::strings absl::str_format absl::utility)
+set(HASH_PUBLIC_LIBRARIES absl::hash absl::fixed_array absl::strings absl::str_format absl::utility)
 
 absl_library(
   TARGET
@@ -48,9 +48,35 @@ absl_library(
 ## TESTS
 #
 
+absl_cc_library(
+  NAME
+    hash_testing
+  HDRS
+    "hash_testing.h"
+  DEPS
+    absl::spy_hash_state
+    absl::meta
+    absl::strings
+    absl::variant
+    gmock
+  TESTONLY
+)
+
+absl_cc_library(
+  NAME
+    spy_hash_state
+  HDRS
+    "internal/spy_hash_state.h"
+  DEPS
+    absl::hash
+    absl::strings
+    absl::str_format
+  TESTONLY
+)
+
 # testing support
 set(HASH_TEST_HEADERS hash_testing.h internal/spy_hash_state.h)
-set(HASH_TEST_PUBLIC_LIBRARIES absl::hash absl::container absl::numeric absl::strings absl::str_format)
+set(HASH_TEST_PUBLIC_LIBRARIES absl::hash absl::flat_hash_set absl::numeric absl::strings absl::str_format)
 
 # hash_test
 set(HASH_TEST_SRC "hash_test.cc" ${HASH_TEST_HEADERS})
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index dbb6ae6a4505..a6574c17af3b 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -113,7 +113,7 @@ absl_library(
     absl::strings
     absl::base
     absl::numeric
-    absl::container
+    absl::inlined_vector
     absl::span
 )
 
diff --git a/absl/time/BUILD.bazel b/absl/time/BUILD.bazel
index 969ddd2e6acf..4d9c01c40a6c 100644
--- a/absl/time/BUILD.bazel
+++ b/absl/time/BUILD.bazel
@@ -110,6 +110,7 @@ cc_test(
         ":test_util",
         ":time",
         "//absl/base",
+        "//absl/hash",
         "@com_github_google_benchmark//:benchmark_main",
     ],
 )
diff --git a/absl/time/civil_time_benchmark.cc b/absl/time/civil_time_benchmark.cc
index 567c2a33b12d..f30f636dccc8 100644
--- a/absl/time/civil_time_benchmark.cc
+++ b/absl/time/civil_time_benchmark.cc
@@ -14,17 +14,29 @@
 
 #include "absl/time/civil_time.h"
 
+#include <numeric>
+#include <vector>
+
+#include "absl/hash/hash.h"
 #include "benchmark/benchmark.h"
 
 namespace {
 
-// Benchmark                            Time(ns)       CPU(ns)    Iterations
-// -------------------------------------------------------------------------
-// BM_Difference_Days                         20            20      34542508
-// BM_Step_Days                               15            15      48098146
-// BM_Format                                 688           687       1019803
-// BM_Parse                                  921           920        762788
-// BM_RoundTripFormatParse                  1766          1764        396092
+// Run on (12 X 3492 MHz CPUs); 2018-11-05T13:44:29.814239103-08:00
+// CPU: Intel Haswell with HyperThreading (6 cores) dL1:32KB dL2:256KB dL3:15MB
+// Benchmark                 Time(ns)        CPU(ns)     Iterations
+// ----------------------------------------------------------------
+// BM_Difference_Days              14.5           14.5     48531105
+// BM_Step_Days                    12.6           12.6     54876006
+// BM_Format                      587            587        1000000
+// BM_Parse                       692            692        1000000
+// BM_RoundTripFormatParse       1309           1309         532075
+// BM_CivilYearAbslHash             0.710          0.710  976400000
+// BM_CivilMonthAbslHash            1.13           1.13   619500000
+// BM_CivilDayAbslHash              1.70           1.70   426000000
+// BM_CivilHourAbslHash             2.45           2.45   287600000
+// BM_CivilMinuteAbslHash           3.21           3.21   226200000
+// BM_CivilSecondAbslHash           4.10           4.10   171800000
 
 void BM_Difference_Days(benchmark::State& state) {
   const absl::CivilDay c(2014, 8, 22);
@@ -54,4 +66,42 @@ void BM_Format(benchmark::State& state) {
 }
 BENCHMARK(BM_Format);
 
+template <typename T>
+void BM_CivilTimeAbslHash(benchmark::State& state) {
+  const int kSize = 100000;
+  std::vector<T> civil_times(kSize);
+  std::iota(civil_times.begin(), civil_times.end(), T(2018));
+
+  absl::Hash<T> absl_hasher;
+  while (state.KeepRunningBatch(kSize)) {
+    for (const T civil_time : civil_times) {
+      benchmark::DoNotOptimize(absl_hasher(civil_time));
+    }
+  }
+}
+void BM_CivilYearAbslHash(benchmark::State& state) {
+  BM_CivilTimeAbslHash<absl::CivilYear>(state);
+}
+void BM_CivilMonthAbslHash(benchmark::State& state) {
+  BM_CivilTimeAbslHash<absl::CivilMonth>(state);
+}
+void BM_CivilDayAbslHash(benchmark::State& state) {
+  BM_CivilTimeAbslHash<absl::CivilDay>(state);
+}
+void BM_CivilHourAbslHash(benchmark::State& state) {
+  BM_CivilTimeAbslHash<absl::CivilHour>(state);
+}
+void BM_CivilMinuteAbslHash(benchmark::State& state) {
+  BM_CivilTimeAbslHash<absl::CivilMinute>(state);
+}
+void BM_CivilSecondAbslHash(benchmark::State& state) {
+  BM_CivilTimeAbslHash<absl::CivilSecond>(state);
+}
+BENCHMARK(BM_CivilYearAbslHash);
+BENCHMARK(BM_CivilMonthAbslHash);
+BENCHMARK(BM_CivilDayAbslHash);
+BENCHMARK(BM_CivilHourAbslHash);
+BENCHMARK(BM_CivilMinuteAbslHash);
+BENCHMARK(BM_CivilSecondAbslHash);
+
 }  // namespace
diff --git a/absl/time/internal/cctz/BUILD.bazel b/absl/time/internal/cctz/BUILD.bazel
index e913fad33cc4..e2cfe801f23d 100644
--- a/absl/time/internal/cctz/BUILD.bazel
+++ b/absl/time/internal/cctz/BUILD.bazel
@@ -12,6 +12,8 @@
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
 
+package(features = ["-parse_headers"])
+
 licenses(["notice"])  # Apache License
 
 ### libraries
diff --git a/absl/time/time.h b/absl/time/time.h
index de12e5608b29..3fa9378fc849 100644
--- a/absl/time/time.h
+++ b/absl/time/time.h
@@ -1336,9 +1336,12 @@ constexpr Duration MakeNormalizedDuration(int64_t sec, int64_t ticks) {
   return (ticks < 0) ? MakeDuration(sec - 1, ticks + kTicksPerSecond)
                      : MakeDuration(sec, ticks);
 }
+
 // Provide access to the Duration representation.
 constexpr int64_t GetRepHi(Duration d) { return d.rep_hi_; }
 constexpr uint32_t GetRepLo(Duration d) { return d.rep_lo_; }
+
+// Returns true iff d is positive or negative infinity.
 constexpr bool IsInfiniteDuration(Duration d) { return GetRepLo(d) == ~0U; }
 
 // Returns an infinite Duration with the opposite sign.
diff --git a/absl/types/CMakeLists.txt b/absl/types/CMakeLists.txt
index bc6c39e9cc99..e86207668539 100644
--- a/absl/types/CMakeLists.txt
+++ b/absl/types/CMakeLists.txt
@@ -123,7 +123,7 @@ absl_library(
 
 # test any_test
 set(ANY_TEST_SRC "any_test.cc")
-set(ANY_TEST_PUBLIC_LIBRARIES absl::base absl_internal_throw_delegate absl::any absl::bad_any_cast test_instance_tracker_lib)
+set(ANY_TEST_PUBLIC_LIBRARIES absl::base absl_internal_throw_delegate absl::any absl::bad_any_cast absl::test_instance_tracker)
 
 absl_test(
   TARGET
@@ -169,7 +169,7 @@ absl_test(
 
 # test span_test
 set(SPAN_TEST_SRC "span_test.cc")
-set(SPAN_TEST_PUBLIC_LIBRARIES absl::base absl::strings absl_internal_throw_delegate absl::span test_instance_tracker_lib)
+set(SPAN_TEST_PUBLIC_LIBRARIES absl::base absl::strings absl_internal_throw_delegate absl::span absl::test_instance_tracker)
 
 absl_test(
   TARGET
diff --git a/absl/types/variant.h b/absl/types/variant.h
index 2f78722f8b7c..28aaef4feb6e 100644
--- a/absl/types/variant.h
+++ b/absl/types/variant.h
@@ -399,9 +399,9 @@ constexpr absl::add_pointer_t<const T> get_if(
 // Calls a provided functor on a given set of variants. `absl::visit()` is
 // commonly used to conditionally inspect the state of a given variant (or set
 // of variants).
-// Requires: The expression in the Effects: element shall be a valid expression
-// of the same type and value category, for all combinations of alternative
-// types of all variants. Otherwise, the program is ill-formed.
+//
+// The functor must return the same type when called with any of the variants'
+// alternatives.
 //
 // Example:
 //
@@ -414,6 +414,7 @@ constexpr absl::add_pointer_t<const T> get_if(
 //   };
 //
 //   // Declare our variant, and call `absl::visit()` on it.
+//   // Note that `GetVariant()` returns void in either case.
 //   absl::variant<int, std::string> foo = std::string("foo");
 //   GetVariant visitor;
 //   absl::visit(visitor, foo);  // Prints `The variant's value is: foo'