Export of internal Abseil changes
--
daf5a2b9ab3507ad5fb9aebe9165933f33098b83 by Abseil Team <absl-team@google.com>:
Absl flat containers reserve enough space even in the presence of tombstones.
PiperOrigin-RevId: 372339945
--
9a61504867ba0eccc5046d7333090fbe3439cdd9 by Abseil Team <absl-team@google.com>:
Add benchmark for BlockingCounter
PiperOrigin-RevId: 372246068
--
91ee87e6de09fc62970667ee52654c9dcf7c478d by Evan Brown <ezb@google.com>:
In absl::StrSplit, support btree_multimap, and other non-std::multimap-multimaps by supporting any map type that returns iterator from insert().
Also:
- Use emplace() instead of insert() when available, not just for std::(multi)map - we can potentially change some string copies to moves this way.
- We no longer need the Insert class so remove it.
PiperOrigin-RevId: 372209653
GitOrigin-RevId: daf5a2b9ab3507ad5fb9aebe9165933f33098b83
Change-Id: I83098fde4a722cd4b682f024d3bfa56c613f960c
diff --git a/absl/container/flat_hash_map_test.cc b/absl/container/flat_hash_map_test.cc
index 89ec60c..8dda1d3 100644
--- a/absl/container/flat_hash_map_test.cc
+++ b/absl/container/flat_hash_map_test.cc
@@ -282,6 +282,32 @@
}
#endif
+TEST(FlatHashMap, Reserve) {
+ // Verify that if we reserve(size() + n) then we can perform n insertions
+ // without a rehash, i.e., without invalidating any references.
+ for (size_t trial = 0; trial < 20; ++trial) {
+ for (size_t initial = 3; initial < 100; ++initial) {
+ // Fill in `initial` entries, then erase 2 of them, then reserve space for
+ // two inserts and check for reference stability while doing the inserts.
+ flat_hash_map<size_t, size_t> map;
+ for (size_t i = 0; i < initial; ++i) {
+ map[i] = i;
+ }
+ map.erase(0);
+ map.erase(1);
+ map.reserve(map.size() + 2);
+ size_t& a2 = map[2];
+ // In the event of a failure, asan will complain in one of these two
+ // assignments.
+ map[initial] = a2;
+ map[initial + 1] = a2;
+ // Fail even when not under asan:
+ size_t& a2new = map[2];
+ EXPECT_EQ(&a2, &a2new);
+ }
+ }
+}
+
} // namespace
} // namespace container_internal
ABSL_NAMESPACE_END
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index 8615de8..b23e007 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -1323,8 +1323,8 @@
}
void reserve(size_t n) {
- size_t m = GrowthToLowerboundCapacity(n);
- if (m > capacity_) {
+ if (n > size() + growth_left()) {
+ size_t m = GrowthToLowerboundCapacity(n);
resize(NormalizeCapacity(m));
}
}
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index f3b08de..1cb5b3e 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -728,6 +728,7 @@
":strings",
"//absl/base:core_headers",
"//absl/base:dynamic_annotations",
+ "//absl/container:btree",
"//absl/container:flat_hash_map",
"//absl/container:node_hash_map",
"@com_google_googletest//:gtest_main",
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index d01f0f1..d3f1523 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -221,9 +221,9 @@
${ABSL_TEST_COPTS}
DEPS
absl::strings
- absl::base
absl::core_headers
absl::dynamic_annotations
+ absl::btree
absl::flat_hash_map
absl::node_hash_map
gmock_main
diff --git a/absl/strings/internal/str_split_internal.h b/absl/strings/internal/str_split_internal.h
index a2f41c1..17c1bfe 100644
--- a/absl/strings/internal/str_split_internal.h
+++ b/absl/strings/internal/str_split_internal.h
@@ -32,7 +32,7 @@
#include <array>
#include <initializer_list>
#include <iterator>
-#include <map>
+#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
@@ -182,6 +182,13 @@
struct HasConstIterator<T, absl::void_t<typename T::const_iterator>>
: std::true_type {};
+// HasEmplace<T>::value is true iff there exists a method T::emplace().
+template <typename T, typename = void>
+struct HasEmplace : std::false_type {};
+template <typename T>
+struct HasEmplace<T, absl::void_t<decltype(std::declval<T>().emplace())>>
+ : std::true_type {};
+
// IsInitializerList<T>::value is true iff T is an std::initializer_list. More
// details below in Splitter<> where this is used.
std::false_type IsInitializerListDispatch(...); // default: No
@@ -372,50 +379,43 @@
// value.
template <typename Container, typename First, typename Second>
struct ConvertToContainer<Container, std::pair<const First, Second>, true> {
+ using iterator = typename Container::iterator;
+
Container operator()(const Splitter& splitter) const {
Container m;
- typename Container::iterator it;
+ iterator it;
bool insert = true;
- for (const auto& sp : splitter) {
+ for (const absl::string_view sv : splitter) {
if (insert) {
- it = Inserter<Container>::Insert(&m, First(sp), Second());
+ it = InsertOrEmplace(&m, sv);
} else {
- it->second = Second(sp);
+ it->second = Second(sv);
}
insert = !insert;
}
return m;
}
- // Inserts the key and value into the given map, returning an iterator to
- // the inserted item. Specialized for std::map and std::multimap to use
- // emplace() and adapt emplace()'s return value.
- template <typename Map>
- struct Inserter {
- using M = Map;
- template <typename... Args>
- static typename M::iterator Insert(M* m, Args&&... args) {
- return m->insert(std::make_pair(std::forward<Args>(args)...)).first;
- }
- };
+ // Inserts the key and an empty value into the map, returning an iterator to
+ // the inserted item. We use emplace() if available, otherwise insert().
+ template <typename M>
+ static absl::enable_if_t<HasEmplace<M>::value, iterator> InsertOrEmplace(
+ M* m, absl::string_view key) {
+ // Use piecewise_construct to support old versions of gcc in which pair
+ // constructor can't otherwise construct string from string_view.
+ return ToIter(m->emplace(std::piecewise_construct, std::make_tuple(key),
+ std::tuple<>()));
+ }
+ template <typename M>
+ static absl::enable_if_t<!HasEmplace<M>::value, iterator> InsertOrEmplace(
+ M* m, absl::string_view key) {
+ return ToIter(m->insert(std::make_pair(First(key), Second(""))));
+ }
- template <typename... Ts>
- struct Inserter<std::map<Ts...>> {
- using M = std::map<Ts...>;
- template <typename... Args>
- static typename M::iterator Insert(M* m, Args&&... args) {
- return m->emplace(std::make_pair(std::forward<Args>(args)...)).first;
- }
- };
-
- template <typename... Ts>
- struct Inserter<std::multimap<Ts...>> {
- using M = std::multimap<Ts...>;
- template <typename... Args>
- static typename M::iterator Insert(M* m, Args&&... args) {
- return m->emplace(std::make_pair(std::forward<Args>(args)...));
- }
- };
+ static iterator ToIter(std::pair<iterator, bool> pair) {
+ return pair.first;
+ }
+ static iterator ToIter(iterator iter) { return iter; }
};
StringType text_;
diff --git a/absl/strings/str_split_test.cc b/absl/strings/str_split_test.cc
index 7f7c097..f472f9e 100644
--- a/absl/strings/str_split_test.cc
+++ b/absl/strings/str_split_test.cc
@@ -29,6 +29,8 @@
#include "gtest/gtest.h"
#include "absl/base/dynamic_annotations.h"
#include "absl/base/macros.h"
+#include "absl/container/btree_map.h"
+#include "absl/container/btree_set.h"
#include "absl/container/flat_hash_map.h"
#include "absl/container/node_hash_map.h"
#include "absl/strings/numbers.h"
@@ -405,6 +407,10 @@
TestConversionOperator<std::set<std::string>>(splitter);
TestConversionOperator<std::multiset<absl::string_view>>(splitter);
TestConversionOperator<std::multiset<std::string>>(splitter);
+ TestConversionOperator<absl::btree_set<absl::string_view>>(splitter);
+ TestConversionOperator<absl::btree_set<std::string>>(splitter);
+ TestConversionOperator<absl::btree_multiset<absl::string_view>>(splitter);
+ TestConversionOperator<absl::btree_multiset<std::string>>(splitter);
TestConversionOperator<std::unordered_set<std::string>>(splitter);
// Tests conversion to map-like objects.
@@ -421,6 +427,22 @@
TestMapConversionOperator<std::multimap<std::string, absl::string_view>>(
splitter);
TestMapConversionOperator<std::multimap<std::string, std::string>>(splitter);
+ TestMapConversionOperator<
+ absl::btree_map<absl::string_view, absl::string_view>>(splitter);
+ TestMapConversionOperator<absl::btree_map<absl::string_view, std::string>>(
+ splitter);
+ TestMapConversionOperator<absl::btree_map<std::string, absl::string_view>>(
+ splitter);
+ TestMapConversionOperator<absl::btree_map<std::string, std::string>>(
+ splitter);
+ TestMapConversionOperator<
+ absl::btree_multimap<absl::string_view, absl::string_view>>(splitter);
+ TestMapConversionOperator<
+ absl::btree_multimap<absl::string_view, std::string>>(splitter);
+ TestMapConversionOperator<
+ absl::btree_multimap<std::string, absl::string_view>>(splitter);
+ TestMapConversionOperator<absl::btree_multimap<std::string, std::string>>(
+ splitter);
TestMapConversionOperator<std::unordered_map<std::string, std::string>>(
splitter);
TestMapConversionOperator<
diff --git a/absl/synchronization/BUILD.bazel b/absl/synchronization/BUILD.bazel
index 5ce1695..92e2448 100644
--- a/absl/synchronization/BUILD.bazel
+++ b/absl/synchronization/BUILD.bazel
@@ -136,6 +136,21 @@
],
)
+cc_binary(
+ name = "blocking_counter_benchmark",
+ testonly = 1,
+ srcs = ["blocking_counter_benchmark.cc"],
+ copts = ABSL_TEST_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ tags = ["benchmark"],
+ visibility = ["//visibility:private"],
+ deps = [
+ ":synchronization",
+ ":thread_pool",
+ "@com_github_google_benchmark//:benchmark_main",
+ ],
+)
+
cc_test(
name = "graphcycles_test",
size = "medium",
diff --git a/absl/synchronization/blocking_counter_benchmark.cc b/absl/synchronization/blocking_counter_benchmark.cc
new file mode 100644
index 0000000..b504d1a
--- /dev/null
+++ b/absl/synchronization/blocking_counter_benchmark.cc
@@ -0,0 +1,83 @@
+// Copyright 2021 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <limits>
+
+#include "absl/synchronization/blocking_counter.h"
+#include "absl/synchronization/internal/thread_pool.h"
+#include "benchmark/benchmark.h"
+
+namespace {
+
+void BM_BlockingCounter_SingleThread(benchmark::State& state) {
+ for (auto _ : state) {
+ int iterations = state.range(0);
+ absl::BlockingCounter counter{iterations};
+ for (int i = 0; i < iterations; ++i) {
+ counter.DecrementCount();
+ }
+ counter.Wait();
+ }
+}
+BENCHMARK(BM_BlockingCounter_SingleThread)
+ ->ArgName("iterations")
+ ->Arg(2)
+ ->Arg(4)
+ ->Arg(16)
+ ->Arg(64)
+ ->Arg(256);
+
+void BM_BlockingCounter_DecrementCount(benchmark::State& state) {
+ static absl::BlockingCounter* counter =
+ new absl::BlockingCounter{std::numeric_limits<int>::max()};
+ for (auto _ : state) {
+ counter->DecrementCount();
+ }
+}
+BENCHMARK(BM_BlockingCounter_DecrementCount)
+ ->Threads(2)
+ ->Threads(4)
+ ->Threads(6)
+ ->Threads(8)
+ ->Threads(10)
+ ->Threads(12)
+ ->Threads(16)
+ ->Threads(32)
+ ->Threads(64)
+ ->Threads(128);
+
+void BM_BlockingCounter_Wait(benchmark::State& state) {
+ int num_threads = state.range(0);
+ absl::synchronization_internal::ThreadPool pool(num_threads);
+ for (auto _ : state) {
+ absl::BlockingCounter counter{num_threads};
+ pool.Schedule([num_threads, &counter, &pool]() {
+ for (int i = 0; i < num_threads; ++i) {
+ pool.Schedule([&counter]() { counter.DecrementCount(); });
+ }
+ });
+ counter.Wait();
+ }
+}
+BENCHMARK(BM_BlockingCounter_Wait)
+ ->ArgName("threads")
+ ->Arg(2)
+ ->Arg(4)
+ ->Arg(8)
+ ->Arg(16)
+ ->Arg(32)
+ ->Arg(64)
+ ->Arg(128);
+
+} // namespace
