Export of internal Abseil changes

--
f8fe0f483378c7520d8f8bdfabe4b20de4d96c7e by Andy Soffer <asoffer@google.com>:

Ensure that Invoke can support C++17 in the sense that noexcept is part of the type.

PiperOrigin-RevId: 261730155

--
bf796ab71653a80498f9374bc8c5111d065c64ba by Abseil Team <absl-team@google.com>:

Fix typo in static_assert message for copy/move constructible by replacing "by" with "be".

PiperOrigin-RevId: 261713992

--
8c7c17c40d03a322f304a2fd73ed34462dbf265a by Andy Soffer <asoffer@google.com>:

Add absl::is_function drop-in replacement for std::is_function. Some standard
libraries incorrectly implement std::is_function in a few corner cases. In
particular, libstdc++ functions marked noexcept.

The trick being used here is that function types decay to pointers. After
excluding cases like is_class, etc, we can distinguish function types by
testing for this decay.

Many thanks to ericwf@ for essentially writing this CL.

PiperOrigin-RevId: 261705008

--
c5adf42d0a132c2525d17a719329eab2ffe0aa94 by Abseil Team <absl-team@google.com>:

Add microbenchmark for StrSplit that uses delimiter ByAnyChar.

PiperOrigin-RevId: 261424010

--
66a342f9381ec56be2fe3aa5b3193dd3538a9740 by Andy Soffer <asoffer@google.com>:

CMake support for Abseil Random

This change touches almost build-related files for CMake almost exclusively. The one minor exception is random/internal/salted_seed_seq.h. The default warnings configuration for one of our CI builds requests not having named but unused parameters. The change in this file cleans up that warning.

PiperOrigin-RevId: 261192369
GitOrigin-RevId: f8fe0f483378c7520d8f8bdfabe4b20de4d96c7e
Change-Id: I05f662baacfe78750651535aa658f61c2327bc44

absl/CMakeLists.txt

@@ -25,6 +25,7 @@ add_subdirectory(hash)
 add_subdirectory(memory)
 add_subdirectory(meta)
 add_subdirectory(numeric)
+add_subdirectory(random)
 add_subdirectory(strings)
 add_subdirectory(synchronization)
 add_subdirectory(time)

absl/base/BUILD.bazel

@@ -155,6 +155,9 @@ cc_library(
     visibility = [
         "//absl:__subpackages__",
     ],
+    deps = [
+        "//absl/meta:type_traits",
+    ],
 )
 
 cc_library(

absl/base/CMakeLists.txt

@@ -133,6 +133,8 @@ absl_cc_library(
     "internal/invoke.h"
   COPTS
     ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::type_traits
 )
 
 absl_cc_library(

absl/base/internal/invoke.h

@@ -39,6 +39,8 @@
 #include <type_traits>
 #include <utility>
 
+#include "absl/meta/type_traits.h"
+
 // The following code is internal implementation detail.  See the comment at the
 // top of this file for the API documentation.
 
@@ -67,15 +69,11 @@ struct MemFunAndRef : StrippedAccept<MemFunAndRef> {
   template <typename... Args>
   struct AcceptImpl : std::false_type {};
 
-  template <typename R, typename C, typename... Params, typename Obj,
-            typename... Args>
-  struct AcceptImpl<R (C::*)(Params...), Obj, Args...>
-      : std::is_base_of<C, Obj> {};
-
-  template <typename R, typename C, typename... Params, typename Obj,
-            typename... Args>
-  struct AcceptImpl<R (C::*)(Params...) const, Obj, Args...>
-      : std::is_base_of<C, Obj> {};
+  template <typename MemFunType, typename C, typename Obj, typename... Args>
+  struct AcceptImpl<MemFunType C::*, Obj, Args...>
+      : std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
+                                         absl::is_function<MemFunType>::value> {
+  };
 
   template <typename MemFun, typename Obj, typename... Args>
   static decltype((std::declval<Obj>().*
@@ -92,15 +90,11 @@ struct MemFunAndPtr : StrippedAccept<MemFunAndPtr> {
   template <typename... Args>
   struct AcceptImpl : std::false_type {};
 
-  template <typename R, typename C, typename... Params, typename Ptr,
-            typename... Args>
-  struct AcceptImpl<R (C::*)(Params...), Ptr, Args...>
-      : std::integral_constant<bool, !std::is_base_of<C, Ptr>::value> {};
-
-  template <typename R, typename C, typename... Params, typename Ptr,
-            typename... Args>
-  struct AcceptImpl<R (C::*)(Params...) const, Ptr, Args...>
-      : std::integral_constant<bool, !std::is_base_of<C, Ptr>::value> {};
+  template <typename MemFunType, typename C, typename Ptr, typename... Args>
+  struct AcceptImpl<MemFunType C::*, Ptr, Args...>
+      : std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
+                                         absl::is_function<MemFunType>::value> {
+  };
 
   template <typename MemFun, typename Ptr, typename... Args>
   static decltype(((*std::declval<Ptr>()).*
@@ -119,7 +113,9 @@ struct DataMemAndRef : StrippedAccept<DataMemAndRef> {
   struct AcceptImpl : std::false_type {};
 
   template <typename R, typename C, typename Obj>
-  struct AcceptImpl<R C::*, Obj> : std::is_base_of<C, Obj> {};
+  struct AcceptImpl<R C::*, Obj>
+      : std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
+                                         !absl::is_function<R>::value> {};
 
   template <typename DataMem, typename Ref>
   static decltype(std::declval<Ref>().*std::declval<DataMem>()) Invoke(
@@ -136,7 +132,8 @@ struct DataMemAndPtr : StrippedAccept<DataMemAndPtr> {
 
   template <typename R, typename C, typename Ptr>
   struct AcceptImpl<R C::*, Ptr>
-      : std::integral_constant<bool, !std::is_base_of<C, Ptr>::value> {};
+      : std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
+                                         !absl::is_function<R>::value> {};
 
   template <typename DataMem, typename Ptr>
   static decltype((*std::declval<Ptr>()).*std::declval<DataMem>()) Invoke(

absl/base/invoke_test.cc

@@ -70,6 +70,10 @@ struct OverloadedFunctor {
 struct Class {
   int Method(int a, int b) { return a - b; }
   int ConstMethod(int a, int b) const { return a - b; }
+  int RefMethod(int a, int b) & { return a - b; }
+  int RefRefMethod(int a, int b) && { return a - b; }
+  int NoExceptMethod(int a, int b) noexcept { return a - b; }
+  int VolatileMethod(int a, int b) volatile { return a - b; }
 
   int member;
 };
@@ -151,8 +155,18 @@ TEST(InvokeTest, ReferenceWrapper) {
 TEST(InvokeTest, MemberFunction) {
   std::unique_ptr<Class> p(new Class);
   std::unique_ptr<const Class> cp(new Class);
+  std::unique_ptr<volatile Class> vp(new Class);
+
   EXPECT_EQ(1, Invoke(&Class::Method, p, 3, 2));
   EXPECT_EQ(1, Invoke(&Class::Method, p.get(), 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::Method, *p, 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::RefMethod, p, 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::RefMethod, p.get(), 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::RefMethod, *p, 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::RefRefMethod, std::move(*p), 3, 2));  // NOLINT
+  EXPECT_EQ(1, Invoke(&Class::NoExceptMethod, p, 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::NoExceptMethod, p.get(), 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::NoExceptMethod, *p, 3, 2));
 
   EXPECT_EQ(1, Invoke(&Class::ConstMethod, p, 3, 2));
   EXPECT_EQ(1, Invoke(&Class::ConstMethod, p.get(), 3, 2));
@@ -162,6 +176,13 @@ TEST(InvokeTest, MemberFunction) {
   EXPECT_EQ(1, Invoke(&Class::ConstMethod, cp.get(), 3, 2));
   EXPECT_EQ(1, Invoke(&Class::ConstMethod, *cp, 3, 2));
 
+  EXPECT_EQ(1, Invoke(&Class::VolatileMethod, p, 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::VolatileMethod, p.get(), 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::VolatileMethod, *p, 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::VolatileMethod, vp, 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::VolatileMethod, vp.get(), 3, 2));
+  EXPECT_EQ(1, Invoke(&Class::VolatileMethod, *vp, 3, 2));
+
   EXPECT_EQ(1, Invoke(&Class::Method, make_unique<Class>(), 3, 2));
   EXPECT_EQ(1, Invoke(&Class::ConstMethod, make_unique<Class>(), 3, 2));
   EXPECT_EQ(1, Invoke(&Class::ConstMethod, make_unique<const Class>(), 3, 2));

absl/copts/AbseilConfigureCopts.cmake

@@ -9,6 +9,7 @@ if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
   set(ABSL_DEFAULT_COPTS "${ABSL_GCC_FLAGS}")
   set(ABSL_TEST_COPTS "${ABSL_GCC_FLAGS};${ABSL_GCC_TEST_FLAGS}")
   set(ABSL_EXCEPTIONS_FLAG "${ABSL_GCC_EXCEPTIONS_FLAGS}")
+  set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_X64_FLAGS}")
 elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
   # MATCHES so we get both Clang and AppleClang
   if(MSVC)
@@ -17,10 +18,12 @@ elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
     set(ABSL_TEST_COPTS "${ABSL_CLANG_CL_FLAGS};${ABSL_CLANG_CL_TEST_FLAGS}")
     set(ABSL_EXCEPTIONS_FLAG "${ABSL_CLANG_CL_EXCEPTIONS_FLAGS}")
     set(ABSL_DEFAULT_LINKOPTS "${ABSL_MSVC_LINKOPTS}")
+    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_MSVC_X64_FLAGS}")
   else()
     set(ABSL_DEFAULT_COPTS "${ABSL_LLVM_FLAGS}")
     set(ABSL_TEST_COPTS "${ABSL_LLVM_FLAGS};${ABSL_LLVM_TEST_FLAGS}")
     set(ABSL_EXCEPTIONS_FLAG "${ABSL_LLVM_EXCEPTIONS_FLAGS}")
+    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_X64_FLAGS}")
     if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
       # AppleClang doesn't have lsan
       # https://developer.apple.com/documentation/code_diagnostics
@@ -35,11 +38,13 @@ elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
   set(ABSL_TEST_COPTS "${ABSL_MSVC_FLAGS};${ABSL_MSVC_TEST_FLAGS}")
   set(ABSL_EXCEPTIONS_FLAG "${ABSL_MSVC_EXCEPTIONS_FLAGS}")
   set(ABSL_DEFAULT_LINKOPTS "${ABSL_MSVC_LINKOPTS}")
+  set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_MSVC_X64_FLAGS}")
 else()
   message(WARNING "Unknown compiler: ${CMAKE_CXX_COMPILER}.  Building with no default flags")
   set(ABSL_DEFAULT_COPTS "")
   set(ABSL_TEST_COPTS "")
   set(ABSL_EXCEPTIONS_FLAG "")
+  set(ABSL_RANDOM_RANDEN_COPTS "")
 endif()
 
 # This flag is used internally for Bazel builds and is kept here for consistency

absl/meta/type_traits.h

@@ -224,6 +224,23 @@ struct disjunction<> : std::false_type {};
 template <typename T>
 struct negation : std::integral_constant<bool, !T::value> {};
 
+// is_function()
+//
+// Determines whether the passed type `T` is a function type.
+//
+// This metafunction is designed to be a drop-in replacement for the C++11
+// `std::is_function()` metafunction for platforms that have incomplete C++11
+// support (such as libstdc++ 4.x).
+//
+// This metafunction works because appending `const` to a type does nothing to
+// function types and reference types (and forms a const-qualified type
+// otherwise).
+template <typename T>
+struct is_function
+    : std::integral_constant<
+          bool, !(std::is_reference<T>::value ||
+                  std::is_const<typename std::add_const<T>::type>::value)> {};
+
 // is_trivially_destructible()
 //
 // Determines whether the passed type `T` is trivially destructable.

absl/meta/type_traits_test.cc

@@ -385,6 +385,22 @@ class Base {
 #define ABSL_GCC_BUG_TRIVIALLY_CONSTRUCTIBLE_ON_ARRAY_OF_NONTRIVIAL 1
 #endif
 
+TEST(TypeTraitsTest, TestIsFunction) {
+  struct Callable {
+    void operator()() {}
+  };
+  EXPECT_TRUE(absl::is_function<void()>::value);
+  EXPECT_TRUE(absl::is_function<void()&>::value);
+  EXPECT_TRUE(absl::is_function<void() const>::value);
+  EXPECT_TRUE(absl::is_function<void() noexcept>::value);
+  EXPECT_TRUE(absl::is_function<void(...) noexcept>::value);
+
+  EXPECT_FALSE(absl::is_function<void(*)()>::value);
+  EXPECT_FALSE(absl::is_function<void(&)()>::value);
+  EXPECT_FALSE(absl::is_function<int>::value);
+  EXPECT_FALSE(absl::is_function<Callable>::value);
+}
+
 TEST(TypeTraitsTest, TestTrivialDestructor) {
   // Verify that arithmetic types and pointers have trivial destructors.
   EXPECT_TRUE(absl::is_trivially_destructible<bool>::value);

absl/random/internal/salted_seed_seq.h

@@ -56,11 +56,11 @@ class SaltedSeedSeq {
   SaltedSeedSeq(std::initializer_list<T> il)
       : SaltedSeedSeq(il.begin(), il.end()) {}
 
-  SaltedSeedSeq(const SaltedSeedSeq& other) = delete;
-  SaltedSeedSeq& operator=(const SaltedSeedSeq& other) = delete;
+  SaltedSeedSeq(const SaltedSeedSeq&) = delete;
+  SaltedSeedSeq& operator=(const SaltedSeedSeq&) = delete;
 
-  SaltedSeedSeq(SaltedSeedSeq&& other) = default;
-  SaltedSeedSeq& operator=(SaltedSeedSeq&& other) = default;
+  SaltedSeedSeq(SaltedSeedSeq&&) = default;
+  SaltedSeedSeq& operator=(SaltedSeedSeq&&) = default;
 
   template <typename RandomAccessIterator>
   void generate(RandomAccessIterator begin, RandomAccessIterator end) {

absl/strings/str_split_benchmark.cc

@@ -44,6 +44,29 @@ void BM_Split2StringView(benchmark::State& state) {
 }
 BENCHMARK_RANGE(BM_Split2StringView, 0, 1 << 20);
 
+static const absl::string_view kDelimiters = ";:,.";
+
+std::string MakeMultiDelimiterTestString(int desired_length) {
+  static const int kAverageValueLen = 25;
+  std::string test(desired_length * kAverageValueLen, 'x');
+  for (int i = 0; i * kAverageValueLen < test.size(); ++i) {
+    // Cycle through a variety of delimiters.
+    test[i * kAverageValueLen] = kDelimiters[i % kDelimiters.size()];
+  }
+  return test;
+}
+
+// Measure StrSplit with ByAnyChar with four delimiters to choose from.
+void BM_Split2StringViewByAnyChar(benchmark::State& state) {
+  std::string test = MakeMultiDelimiterTestString(state.range(0));
+  for (auto _ : state) {
+    std::vector<absl::string_view> result =
+        absl::StrSplit(test, absl::ByAnyChar(kDelimiters));
+    benchmark::DoNotOptimize(result);
+  }
+}
+BENCHMARK_RANGE(BM_Split2StringViewByAnyChar, 0, 1 << 20);
+
 void BM_Split2StringViewLifted(benchmark::State& state) {
   std::string test = MakeTestString(state.range(0));
   std::vector<absl::string_view> result;

absl/types/optional.h

@@ -499,7 +499,7 @@ class optional : private optional_internal::optional_data<T>,
   template <typename U>
   constexpr T value_or(U&& v) const& {
     static_assert(std::is_copy_constructible<value_type>::value,
-                  "optional<T>::value_or: T must by copy constructible");
+                  "optional<T>::value_or: T must be copy constructible");
     static_assert(std::is_convertible<U&&, value_type>::value,
                   "optional<T>::value_or: U must be convertible to T");
     return static_cast<bool>(*this)
@@ -509,7 +509,7 @@ class optional : private optional_internal::optional_data<T>,
   template <typename U>
   T value_or(U&& v) && {  // NOLINT(build/c++11)
     static_assert(std::is_move_constructible<value_type>::value,
-                  "optional<T>::value_or: T must by move constructible");
+                  "optional<T>::value_or: T must be move constructible");
     static_assert(std::is_convertible<U&&, value_type>::value,
                   "optional<T>::value_or: U must be convertible to T");
     return static_cast<bool>(*this) ? std::move(**this)