Abseil LTS 2020092320200923

What's New:
* `absl::StatusOr<T>` has been released. See our [blog
  post](https://abseil.io/blog/2020-091021-status) for more
  information.
* Abseil Flags reflection interfaces have been released.
* Abseil Flags memory usage has been significantly optimized.
* Abseil now supports a "hardened" build mode. This build mode enables
  runtime checks that guard against programming errors that may lead
  to security vulnerabilities.

Notable Fixes:
* Sanitizer dynamic annotations like `AnnotateRWLockCreate` that are
  also defined by the compiler sanitizer implementation are no longer
  also defined by Abseil.
* Sanitizer macros are now prefixed with `ABSL_` to avoid naming collisions.
* Sanitizer usage is now automatically detected and no longer requires
  macros like `ADDRESS_SANITIZER` to be defined on the command line.

Breaking Changes:
* Abseil no longer contains a `dynamic_annotations` library. Users
  using a supported build system (Bazel or CMake) are unaffected by
  this, but users manually specifying link libraries may get an error
  about a missing linker input.

Baseline: 7680a5f8efe32de4753baadbd63e74e59d95bac1
Cherry picks: None

1 files changed, 40 insertions, 12 deletions

diff --git a/absl/container/btree_benchmark.cc b/absl/container/btree_benchmark.cc
index 4af92f9f..46798676 100644
--- a/absl/container/btree_benchmark.cc
+++ b/absl/container/btree_benchmark.cc
@@ -36,6 +36,7 @@
 #include "absl/flags/flag.h"
 #include "absl/hash/hash.h"
 #include "absl/memory/memory.h"
+#include "absl/strings/cord.h"
 #include "absl/strings/str_format.h"
 #include "absl/time/time.h"
 #include "benchmark/benchmark.h"
@@ -133,6 +134,27 @@ void BM_InsertEnd(benchmark::State& state) {
   }
 }
 
+// Benchmark inserting the first few elements in a container. In b-tree, this is
+// when the root node grows.
+template <typename T>
+void BM_InsertSmall(benchmark::State& state) {
+  using V = typename remove_pair_const<typename T::value_type>::type;
+
+  const int kSize = 8;
+  std::vector<V> values = GenerateValues<V>(kSize);
+  T container;
+
+  while (state.KeepRunningBatch(kSize)) {
+    for (int i = 0; i < kSize; ++i) {
+      benchmark::DoNotOptimize(container.insert(values[i]));
+    }
+    state.PauseTiming();
+    // Do not measure the time it takes to clear the container.
+    container.clear();
+    state.ResumeTiming();
+  }
+}
+
 template <typename T>
 void BM_LookupImpl(benchmark::State& state, bool sorted) {
   using V = typename remove_pair_const<typename T::value_type>::type;
@@ -438,6 +460,7 @@ using StdString = std::string;
 STL_ORDERED_TYPES(int32_t);
 STL_ORDERED_TYPES(int64_t);
 STL_ORDERED_TYPES(StdString);
+STL_ORDERED_TYPES(Cord);
 STL_ORDERED_TYPES(Time);
 
 #define STL_UNORDERED_TYPES(value)                                       \
@@ -458,6 +481,8 @@ STL_ORDERED_TYPES(Time);
   using stl_unordered_multimap_##value =                                       \
       std::unordered_multimap<value, intptr_t, hash>
 
+STL_UNORDERED_TYPES_CUSTOM_HASH(Cord, absl::Hash<absl::Cord>);
+
 STL_UNORDERED_TYPES(int32_t);
 STL_UNORDERED_TYPES(int64_t);
 STL_UNORDERED_TYPES(StdString);
@@ -478,6 +503,7 @@ STL_UNORDERED_TYPES_CUSTOM_HASH(Time, absl::Hash<absl::Time>);
 BTREE_TYPES(int32_t);
 BTREE_TYPES(int64_t);
 BTREE_TYPES(StdString);
+BTREE_TYPES(Cord);
 BTREE_TYPES(Time);
 
 #define MY_BENCHMARK4(type, func)                                              \
@@ -488,6 +514,7 @@ BTREE_TYPES(Time);
   MY_BENCHMARK4(type, Insert);            \
   MY_BENCHMARK4(type, InsertSorted);      \
   MY_BENCHMARK4(type, InsertEnd);         \
+  MY_BENCHMARK4(type, InsertSmall);       \
   MY_BENCHMARK4(type, Lookup);            \
   MY_BENCHMARK4(type, FullLookup);        \
   MY_BENCHMARK4(type, Delete);            \
@@ -526,6 +553,7 @@ BTREE_TYPES(Time);
 MY_BENCHMARK(int32_t);
 MY_BENCHMARK(int64_t);
 MY_BENCHMARK(StdString);
+MY_BENCHMARK(Cord);
 MY_BENCHMARK(Time);
 
 // Define a type whose size and cost of moving are independently customizable.
@@ -538,19 +566,19 @@ struct BigType {
   BigType() : BigType(0) {}
   explicit BigType(int x) { std::iota(values.begin(), values.end(), x); }
 
-  void Copy(const BigType& x) {
-    for (int i = 0; i < Size && i < Copies; ++i) values[i] = x.values[i];
+  void Copy(const BigType& other) {
+    for (int i = 0; i < Size && i < Copies; ++i) values[i] = other.values[i];
     // If Copies > Size, do extra copies.
     for (int i = Size, idx = 0; i < Copies; ++i) {
-      int64_t tmp = x.values[idx];
+      int64_t tmp = other.values[idx];
       benchmark::DoNotOptimize(tmp);
       idx = idx + 1 == Size ? 0 : idx + 1;
     }
   }
 
-  BigType(const BigType& x) { Copy(x); }
-  BigType& operator=(const BigType& x) {
-    Copy(x);
+  BigType(const BigType& other) { Copy(other); }
+  BigType& operator=(const BigType& other) {
+    Copy(other);
     return *this;
   }
 
@@ -641,14 +669,14 @@ struct BigTypePtr {
   explicit BigTypePtr(int x) {
     ptr = absl::make_unique<BigType<Size, Size>>(x);
   }
-  BigTypePtr(const BigTypePtr& x) {
-    ptr = absl::make_unique<BigType<Size, Size>>(*x.ptr);
+  BigTypePtr(const BigTypePtr& other) {
+    ptr = absl::make_unique<BigType<Size, Size>>(*other.ptr);
   }
-  BigTypePtr(BigTypePtr&& x) noexcept = default;
-  BigTypePtr& operator=(const BigTypePtr& x) {
-    ptr = absl::make_unique<BigType<Size, Size>>(*x.ptr);
+  BigTypePtr(BigTypePtr&& other) noexcept = default;
+  BigTypePtr& operator=(const BigTypePtr& other) {
+    ptr = absl::make_unique<BigType<Size, Size>>(*other.ptr);
   }
-  BigTypePtr& operator=(BigTypePtr&& x) noexcept = default;
+  BigTypePtr& operator=(BigTypePtr&& other) noexcept = default;
 
   bool operator<(const BigTypePtr& other) const { return *ptr < *other.ptr; }
   bool operator==(const BigTypePtr& other) const { return *ptr == *other.ptr; }