Export of internal Abseil changes.

--
5da9755667df37e38ccaf6938c9f408e294110bb by Shaindel Schwartz <shaindel@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 232942734

--
b6fb275769c66fdd2bd92b119198c59e9a7dd737 by Samuel Benzaquen <sbenza@google.com>:

Fix integral underflow when from-arg width is INT_MIN.

PiperOrigin-RevId: 232888037

--
4135dbba4a26c4642277fc2a7e2a833d593daa1c by Abseil Team <absl-team@google.com>:

Add the insert_return_type alias to raw_hash_set.

PiperOrigin-RevId: 232683892

--
0b120b7d3693800bbb886f6fc607ae54a9338cb1 by Abseil Team <absl-team@google.com>:

Macros to detect and disabled SafeStack
https://clang.llvm.org/docs/SafeStack.html

PiperOrigin-RevId: 232680114

--
a77b3fb533a9e37966d1d6ef5ccd09c73fff2ca1 by Abseil Team <absl-team@google.com>:

Avoid potential red zone clobber

Pushing on the stack on x86-64 may clobber local variables held below
%rsp in the red zone. Avoid this by using lea on x86-64.

PiperOrigin-RevId: 232592478

--
bf326a0eefa92f4e704287563df0c5a5b1873b6d by Eric Fiselier <ericwf@google.com>:

Add additional tests for AbslHashValue.

PiperOrigin-RevId: 232344325

--
816e4f98fd7632c944c779db87b7dac4e138afcf by Eric Fiselier <ericwf@google.com>:

Avoid upcoming GCC 9.0 warnings about base class init.

Currently, in trunk, GCC has a new warning under -Wextra
that diagnoses when a derived class fails to explicitly
initialize the base class in a constructor initializer list.

This patch avoids this warning.

PiperOrigin-RevId: 232327626

--
779c0f44b3c2b7a04d4bdf978641eb8180515bf6 by Eric Fiselier <ericwf@google.com>:

Guard against C++2a char8_t change.

PiperOrigin-RevId: 232326178

--
41e5395b85bbbfb5bf418cc21b04ad4ccb15a284 by Eric Fiselier <ericwf@google.com>:

Avoid Clang Warning

PiperOrigin-RevId: 232138866
GitOrigin-RevId: 5da9755667df37e38ccaf6938c9f408e294110bb
Change-Id: I49ee4f58db177b81b039d7d949f671c97c5a7933

18 files changed, 287 insertions, 145 deletions

diff --git a/absl/base/attributes.h b/absl/base/attributes.h
index 291ad89e..fa44012e 100644
--- a/absl/base/attributes.h
+++ b/absl/base/attributes.h
@@ -287,6 +287,17 @@
 #define ABSL_ATTRIBUTE_NO_SANITIZE_CFI
 #endif
 
+// ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK
+//
+// Tells the SafeStack to not instrument a given function.
+// See https://clang.llvm.org/docs/SafeStack.html for details.
+#if defined(__GNUC__) && defined(SAFESTACK_SANITIZER)
+#define ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK \
+  __attribute__((no_sanitize("safe-stack")))
+#else
+#define ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK
+#endif
+
 // ABSL_ATTRIBUTE_RETURNS_NONNULL
 //
 // Tells the compiler that a particular function never returns a null pointer.
diff --git a/absl/container/BUILD.bazel b/absl/container/BUILD.bazel
index acdbc473..f3b3a2c0 100644
--- a/absl/container/BUILD.bazel
+++ b/absl/container/BUILD.bazel
@@ -542,6 +542,7 @@ cc_library(
     copts = ABSL_DEFAULT_COPTS,
     deps = [
         "//absl/meta:type_traits",
+        "//absl/types:optional",
     ],
 )
 
@@ -565,7 +566,6 @@ cc_library(
         "//absl/base:endian",
         "//absl/memory",
         "//absl/meta:type_traits",
-        "//absl/types:optional",
         "//absl/utility",
     ],
 )
diff --git a/absl/container/fixed_array_test.cc b/absl/container/fixed_array_test.cc
index 205ff41f..1679ba4f 100644
--- a/absl/container/fixed_array_test.cc
+++ b/absl/container/fixed_array_test.cc
@@ -869,4 +869,21 @@ TEST(FixedArrayTest, AddressSanitizerAnnotations4) {
 }
 #endif  // ADDRESS_SANITIZER
 
+TEST(FixedArrayTest, AbslHashValueWorks) {
+  using V = absl::FixedArray<int>;
+  std::vector<V> cases;
+
+  // Generate a variety of vectors some of these are small enough for the inline
+  // space but are stored out of line.
+  for (int i = 0; i < 10; ++i) {
+    V v(i);
+    for (int j = 0; j < i; ++j) {
+      v[j] = j;
+    }
+    cases.push_back(v);
+  }
+
+  EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(cases));
+}
+
 }  // namespace
diff --git a/absl/container/inlined_vector_test.cc b/absl/container/inlined_vector_test.cc
index 9408ee9d..5b1527e9 100644
--- a/absl/container/inlined_vector_test.cc
+++ b/absl/container/inlined_vector_test.cc
@@ -1762,4 +1762,23 @@ TEST(AllocatorSupportTest, SizeAllocConstructor) {
   }
 }
 
+TEST(InlinedVectorTest, AbslHashValueWorks) {
+  using V = absl::InlinedVector<int, 4>;
+  std::vector<V> cases;
+
+  // Generate a variety of vectors some of these are small enough for the inline
+  // space but are stored out of line.
+  for (int i = 0; i < 10; ++i) {
+    V v;
+    for (int j = 0; j < i; ++j) {
+      v.push_back(j);
+    }
+    cases.push_back(v);
+    v.resize(i % 4);
+    cases.push_back(v);
+  }
+
+  EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(cases));
+}
+
 }  // anonymous namespace
diff --git a/absl/container/internal/common.h b/absl/container/internal/common.h
index a6dc9103..c7816566 100644
--- a/absl/container/internal/common.h
+++ b/absl/container/internal/common.h
@@ -18,6 +18,7 @@
 #include <type_traits>
 
 #include "absl/meta/type_traits.h"
+#include "absl/types/optional.h"
 
 namespace absl {
 namespace container_internal {
@@ -42,7 +43,140 @@ struct KeyArg<false> {
   using type = key_type;
 };
 
+// The node_handle concept from C++17.
+// We specialize node_handle for sets and maps. node_handle_base holds the
+// common API of both.
+template <typename PolicyTraits, typename Alloc>
+class node_handle_base {
+ protected:
+  using slot_type = typename PolicyTraits::slot_type;
+
+ public:
+  using allocator_type = Alloc;
+
+  constexpr node_handle_base() {}
+  node_handle_base(node_handle_base&& other) noexcept {
+    *this = std::move(other);
+  }
+  ~node_handle_base() { destroy(); }
+  node_handle_base& operator=(node_handle_base&& other) noexcept {
+    destroy();
+    if (!other.empty()) {
+      alloc_ = other.alloc_;
+      PolicyTraits::transfer(alloc(), slot(), other.slot());
+      other.reset();
+    }
+    return *this;
+  }
+
+  bool empty() const noexcept { return !alloc_; }
+  explicit operator bool() const noexcept { return !empty(); }
+  allocator_type get_allocator() const { return *alloc_; }
+
+ protected:
+  friend struct CommonAccess;
+
+  node_handle_base(const allocator_type& a, slot_type* s) : alloc_(a) {
+    PolicyTraits::transfer(alloc(), slot(), s);
+  }
+
+  void destroy() {
+    if (!empty()) {
+      PolicyTraits::destroy(alloc(), slot());
+      reset();
+    }
+  }
+
+  void reset() {
+    assert(alloc_.has_value());
+    alloc_ = absl::nullopt;
+  }
+
+  slot_type* slot() const {
+    assert(!empty());
+    return reinterpret_cast<slot_type*>(std::addressof(slot_space_));
+  }
+  allocator_type* alloc() { return std::addressof(*alloc_); }
+
+ private:
+  absl::optional<allocator_type> alloc_;
+  mutable absl::aligned_storage_t<sizeof(slot_type), alignof(slot_type)>
+      slot_space_;
+};
+
+// For sets.
+template <typename Policy, typename PolicyTraits, typename Alloc,
+          typename = void>
+class node_handle : public node_handle_base<PolicyTraits, Alloc> {
+  using Base = typename node_handle::node_handle_base;
+
+ public:
+  using value_type = typename PolicyTraits::value_type;
+
+  constexpr node_handle() {}
+
+  value_type& value() const { return PolicyTraits::element(this->slot()); }
+
+ private:
+  friend struct CommonAccess;
+
+  node_handle(const Alloc& a, typename Base::slot_type* s) : Base(a, s) {}
+};
+
+// For maps.
+template <typename Policy, typename PolicyTraits, typename Alloc>
+class node_handle<Policy, PolicyTraits, Alloc,
+                  absl::void_t<typename Policy::mapped_type>>
+    : public node_handle_base<PolicyTraits, Alloc> {
+  using Base = typename node_handle::node_handle_base;
+
+ public:
+  using key_type = typename Policy::key_type;
+  using mapped_type = typename Policy::mapped_type;
+
+  constexpr node_handle() {}
+
+  auto key() const -> decltype(PolicyTraits::key(this->slot())) {
+    return PolicyTraits::key(this->slot());
+  }
+
+  mapped_type& mapped() const {
+    return PolicyTraits::value(&PolicyTraits::element(this->slot()));
+  }
+
+ private:
+  friend struct CommonAccess;
+
+  node_handle(const Alloc& a, typename Base::slot_type* s) : Base(a, s) {}
+};
+
+// Provide access to non-public node-handle functions.
+struct CommonAccess {
+  template <typename Node>
+  static auto GetSlot(const Node& node) -> decltype(node.slot()) {
+    return node.slot();
+  }
+
+  template <typename Node>
+  static void Reset(Node* node) {
+    node->reset();
+  }
+
+  template <typename T, typename... Args>
+  static T Make(Args&&... args) {
+    return T(std::forward<Args>(args)...);
+  }
+};
+
+// Implement the insert_return_type<> concept of C++17.
+template <class Iterator, class NodeType>
+struct InsertReturnType {
+  Iterator position;
+  bool inserted;
+  NodeType node;
+};
+
 }  // namespace container_internal
-}   // namespace absl
+}  // namespace absl
 
 #endif  // ABSL_CONTAINER_INTERNAL_CONTAINER_H_
diff --git a/absl/container/internal/hashtablez_sampler.cc b/absl/container/internal/hashtablez_sampler.cc
index 99cd8344..dc669248 100644
--- a/absl/container/internal/hashtablez_sampler.cc
+++ b/absl/container/internal/hashtablez_sampler.cc
@@ -254,7 +254,7 @@ HashtablezInfo* SampleSlow(int64_t* next_sample) {
 }
 
 #if ABSL_PER_THREAD_TLS == 1
-ABSL_PER_THREAD_TLS_KEYWORD int64_t next_sample = 0;
+ABSL_PER_THREAD_TLS_KEYWORD int64_t global_next_sample = 0;
 #endif  // ABSL_PER_THREAD_TLS == 1
 
 void UnsampleSlow(HashtablezInfo* info) {
diff --git a/absl/container/internal/hashtablez_sampler.h b/absl/container/internal/hashtablez_sampler.h
index 126a0ade..8b81653a 100644
--- a/absl/container/internal/hashtablez_sampler.h
+++ b/absl/container/internal/hashtablez_sampler.h
@@ -146,23 +146,23 @@ class HashtablezInfoHandle {
   HashtablezInfo* info_;
 };
 
-// Returns an RAII sampling handle that manages registration and unregistation
-// with the global sampler.
 #if ABSL_PER_THREAD_TLS == 1
-extern ABSL_PER_THREAD_TLS_KEYWORD int64_t next_sample;
+extern ABSL_PER_THREAD_TLS_KEYWORD int64_t global_next_sample;
 #endif  // ABSL_PER_THREAD_TLS
 
+// Returns an RAII sampling handle that manages registration and unregistation
+// with the global sampler.
 inline HashtablezInfoHandle Sample() {
 #if ABSL_PER_THREAD_TLS == 0
   static auto* mu = new absl::Mutex;
-  static int64_t next_sample = 0;
+  static int64_t global_next_sample = 0;
   absl::MutexLock l(mu);
 #endif  // !ABSL_HAVE_THREAD_LOCAL
 
-  if (ABSL_PREDICT_TRUE(--next_sample > 0)) {
+  if (ABSL_PREDICT_TRUE(--global_next_sample > 0)) {
     return HashtablezInfoHandle(nullptr);
   }
-  return HashtablezInfoHandle(SampleSlow(&next_sample));
+  return HashtablezInfoHandle(SampleSlow(&global_next_sample));
 }
 
 // Holds samples and their associated stack traces with a soft limit of
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index 8e3fa02d..a5d0cae0 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -115,7 +115,6 @@
 #include "absl/container/internal/layout.h"
 #include "absl/memory/memory.h"
 #include "absl/meta/type_traits.h"
-#include "absl/types/optional.h"
 #include "absl/utility/utility.h"
 
 namespace absl {
@@ -502,126 +501,6 @@ inline size_t GrowthToLowerboundCapacity(size_t growth) {
   return growth + static_cast<size_t>((static_cast<int64_t>(growth) - 1) / 7);
 }
 
-// The node_handle concept from C++17.
-// We specialize node_handle for sets and maps. node_handle_base holds the
-// common API of both.
-template <typename Policy, typename Alloc>
-class node_handle_base {
- protected:
-  using PolicyTraits = hash_policy_traits<Policy>;
-  using slot_type = typename PolicyTraits::slot_type;
-
- public:
-  using allocator_type = Alloc;
-
-  constexpr node_handle_base() {}
-  node_handle_base(node_handle_base&& other) noexcept {
-    *this = std::move(other);
-  }
-  ~node_handle_base() { destroy(); }
-  node_handle_base& operator=(node_handle_base&& other) {
-    destroy();
-    if (!other.empty()) {
-      alloc_ = other.alloc_;
-      PolicyTraits::transfer(alloc(), slot(), other.slot());
-      other.reset();
-    }
-    return *this;
-  }
-
-  bool empty() const noexcept { return !alloc_; }
-  explicit operator bool() const noexcept { return !empty(); }
-  allocator_type get_allocator() const { return *alloc_; }
-
- protected:
-  template <typename, typename, typename, typename>
-  friend class raw_hash_set;
-
-  node_handle_base(const allocator_type& a, slot_type* s) : alloc_(a) {
-    PolicyTraits::transfer(alloc(), slot(), s);
-  }
-
-  void destroy() {
-    if (!empty()) {
-      PolicyTraits::destroy(alloc(), slot());
-      reset();
-    }
-  }
-
-  void reset() {
-    assert(alloc_.has_value());
-    alloc_ = absl::nullopt;
-  }
-
-  slot_type* slot() const {
-    assert(!empty());
-    return reinterpret_cast<slot_type*>(std::addressof(slot_space_));
-  }
-  allocator_type* alloc() { return std::addressof(*alloc_); }
-
- private:
-  absl::optional<allocator_type> alloc_;
-  mutable absl::aligned_storage_t<sizeof(slot_type), alignof(slot_type)>
-      slot_space_;
-};
-
-// For sets.
-template <typename Policy, typename Alloc, typename = void>
-class node_handle : public node_handle_base<Policy, Alloc> {
-  using Base = typename node_handle::node_handle_base;
-
- public:
-  using value_type = typename Base::PolicyTraits::value_type;
-
-  constexpr node_handle() {}
-
-  value_type& value() const {
-    return Base::PolicyTraits::element(this->slot());
-  }
-
- private:
-  template <typename, typename, typename, typename>
-  friend class raw_hash_set;
-
-  node_handle(const Alloc& a, typename Base::slot_type* s) : Base(a, s) {}
-};
-
-// For maps.
-template <typename Policy, typename Alloc>
-class node_handle<Policy, Alloc, absl::void_t<typename Policy::mapped_type>>
-    : public node_handle_base<Policy, Alloc> {
-  using Base = typename node_handle::node_handle_base;
-
- public:
-  using key_type = typename Policy::key_type;
-  using mapped_type = typename Policy::mapped_type;
-
-  constexpr node_handle() {}
-
-  auto key() const -> decltype(Base::PolicyTraits::key(this->slot())) {
-    return Base::PolicyTraits::key(this->slot());
-  }
-
-  mapped_type& mapped() const {
-    return Base::PolicyTraits::value(
-        &Base::PolicyTraits::element(this->slot()));
-  }
-
- private:
-  template <typename, typename, typename, typename>
-  friend class raw_hash_set;
-
-  node_handle(const Alloc& a, typename Base::slot_type* s) : Base(a, s) {}
-};
-
-// Implement the insert_return_type<> concept of C++17.
-template <class Iterator, class NodeType>
-struct insert_return_type {
-  Iterator position;
-  bool inserted;
-  NodeType node;
-};
-
 // Policy: a policy defines how to perform different operations on
 // the slots of the hashtable (see hash_policy_traits.h for the full interface
 // of policy).
@@ -828,7 +707,8 @@ class raw_hash_set {
     iterator inner_;
   };
 
-  using node_type = container_internal::node_handle<Policy, Alloc>;
+  using node_type = node_handle<Policy, hash_policy_traits<Policy>, Alloc>;
+  using insert_return_type = InsertReturnType<iterator, node_type>;
 
   raw_hash_set() noexcept(
       std::is_nothrow_default_constructible<hasher>::value&&
@@ -1136,13 +1016,14 @@ class raw_hash_set {
     insert(ilist.begin(), ilist.end());
   }
 
-  insert_return_type<iterator, node_type> insert(node_type&& node) {
+  insert_return_type insert(node_type&& node) {
     if (!node) return {end(), false, node_type()};
-    const auto& elem = PolicyTraits::element(node.slot());
+    const auto& elem = PolicyTraits::element(CommonAccess::GetSlot(node));
     auto res = PolicyTraits::apply(
-        InsertSlot<false>{*this, std::move(*node.slot())}, elem);
+        InsertSlot<false>{*this, std::move(*CommonAccess::GetSlot(node))},
+        elem);
     if (res.second) {
-      node.reset();
+      CommonAccess::Reset(&node);
       return {res.first, true, node_type()};
     } else {
       return {res.first, false, std::move(node)};
@@ -1306,7 +1187,8 @@ class raw_hash_set {
   }
 
   node_type extract(const_iterator position) {
-    node_type node(alloc_ref(), position.inner_.slot_);
+    auto node =
+        CommonAccess::Make<node_type>(alloc_ref(), position.inner_.slot_);
     erase_meta_only(position);
     return node;
   }
diff --git a/absl/container/internal/raw_hash_set_test.cc b/absl/container/internal/raw_hash_set_test.cc
index d9f1826a..7adcc96d 100644
--- a/absl/container/internal/raw_hash_set_test.cc
+++ b/absl/container/internal/raw_hash_set_test.cc
@@ -1706,7 +1706,7 @@ TEST(Nodes, ExtractInsert) {
   EXPECT_FALSE(node.empty());
 
   StringTable t2;
-  auto res = t2.insert(std::move(node));
+  StringTable::insert_return_type res = t2.insert(std::move(node));
   EXPECT_TRUE(res.inserted);
   EXPECT_THAT(*res.position, Pair(k0, ""));
   EXPECT_FALSE(res.node);
diff --git a/absl/debugging/symbolize_test.cc b/absl/debugging/symbolize_test.cc
index 8029fbe9..dcb52695 100644
--- a/absl/debugging/symbolize_test.cc
+++ b/absl/debugging/symbolize_test.cc
@@ -392,16 +392,20 @@ TEST(Symbolize, ForEachSection) {
 extern "C" {
 inline void *ABSL_ATTRIBUTE_ALWAYS_INLINE inline_func() {
   void *pc = nullptr;
-#if defined(__i386__) || defined(__x86_64__)
-  __asm__ __volatile__("call 1f; 1: pop %0" : "=r"(pc));
+#if defined(__i386__)
+  __asm__ __volatile__("call 1f;\n 1: pop %[PC]" : [ PC ] "=r"(pc));
+#elif defined(__x86_64__)
+  __asm__ __volatile__("leaq 0(%%rip),%[PC];\n" : [ PC ] "=r"(pc));
 #endif
   return pc;
 }
 
 void *ABSL_ATTRIBUTE_NOINLINE non_inline_func() {
   void *pc = nullptr;
-#if defined(__i386__) || defined(__x86_64__)
-  __asm__ __volatile__("call 1f; 1: pop %0" : "=r"(pc));
+#if defined(__i386__)
+  __asm__ __volatile__("call 1f;\n 1: pop %[PC]" : [ PC ] "=r"(pc));
+#elif defined(__x86_64__)
+  __asm__ __volatile__("leaq 0(%%rip),%[PC];\n" : [ PC ] "=r"(pc));
 #endif
   return pc;
 }
diff --git a/absl/numeric/int128_test.cc b/absl/numeric/int128_test.cc
index 81c868d7..4a6eb455 100644
--- a/absl/numeric/int128_test.cc
+++ b/absl/numeric/int128_test.cc
@@ -440,4 +440,29 @@ TEST(Uint128, NumericLimitsTest) {
   EXPECT_EQ(absl::Uint128Max(), std::numeric_limits<absl::uint128>::max());
 }
 
+TEST(Uint128, Hash) {
+  EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly({
+      // Some simple values
+      absl::uint128{0},
+      absl::uint128{1},
+      ~absl::uint128{},
+      // 64 bit limits
+      absl::uint128{std::numeric_limits<int64_t>::max()},
+      absl::uint128{std::numeric_limits<uint64_t>::max()} + 0,
+      absl::uint128{std::numeric_limits<uint64_t>::max()} + 1,
+      absl::uint128{std::numeric_limits<uint64_t>::max()} + 2,
+      // Keeping high same
+      absl::uint128{1} << 62,
+      absl::uint128{1} << 63,
+      // Keeping low same
+      absl::uint128{1} << 64,
+      absl::uint128{1} << 65,
+      // 128 bit limits
+      std::numeric_limits<absl::uint128>::max(),
+      std::numeric_limits<absl::uint128>::max() - 1,
+      std::numeric_limits<absl::uint128>::min() + 1,
+      std::numeric_limits<absl::uint128>::min(),
+  }));
+}
+
 }  // namespace
diff --git a/absl/strings/internal/str_format/bind.cc b/absl/strings/internal/str_format/bind.cc
index 758adb7a..a89295d5 100644
--- a/absl/strings/internal/str_format/bind.cc
+++ b/absl/strings/internal/str_format/bind.cc
@@ -53,7 +53,8 @@ inline bool ArgContext::Bind(const UnboundConversion* unbound,
         // "A negative field width is taken as a '-' flag followed by a
         // positive field width."
         force_left = true;
-        width = -width;
+        // Make sure we don't overflow the width when negating it.
+        width = -std::max(width, -std::numeric_limits<int>::max());
       }
     }
 
diff --git a/absl/strings/internal/str_format/bind_test.cc b/absl/strings/internal/str_format/bind_test.cc
index 47575739..ba6470ec 100644
--- a/absl/strings/internal/str_format/bind_test.cc
+++ b/absl/strings/internal/str_format/bind_test.cc
@@ -1,6 +1,7 @@
 #include "absl/strings/internal/str_format/bind.h"
 
 #include <string.h>
+#include <limits>
 
 #include "gtest/gtest.h"
 
@@ -91,6 +92,20 @@ TEST_F(FormatBindTest, BindSingle) {
   }
 }
 
+TEST_F(FormatBindTest, WidthUnderflowRegression) {
+  UnboundConversion props;
+  BoundConversion bound;
+  int next = 0;
+  const int args_i[] = {std::numeric_limits<int>::min(), 17};
+  const FormatArgImpl args[] = {FormatArgImpl(args_i[0]),
+                                FormatArgImpl(args_i[1])};
+  ASSERT_TRUE(Extract("*d", &props, &next));
+  ASSERT_TRUE(BindWithPack(&props, args, &bound));
+
+  EXPECT_EQ(bound.width(), std::numeric_limits<int>::max());
+  EXPECT_EQ(bound.arg(), args + 1);
+}
+
 TEST_F(FormatBindTest, FormatPack) {
   struct Expectation {
     int line;
diff --git a/absl/strings/internal/utf8_test.cc b/absl/strings/internal/utf8_test.cc
index 64cec70d..07a000cb 100644
--- a/absl/strings/internal/utf8_test.cc
+++ b/absl/strings/internal/utf8_test.cc
@@ -22,6 +22,11 @@
 
 namespace {
 
+#if !defined(__cpp_char8_t)
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc++2a-compat"
+#endif
 TEST(EncodeUTF8Char, BasicFunction) {
   std::pair<char32_t, std::string> tests[] = {{0x0030, u8"\u0030"},
                                          {0x00A3, u8"\u00A3"},
@@ -53,5 +58,9 @@ TEST(EncodeUTF8Char, BasicFunction) {
   EXPECT_LE(absl::strings_internal::EncodeUTF8Char(buf2, -1),
             absl::strings_internal::kMaxEncodedUTF8Size);
 }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+#endif  // !defined(__cpp_char8_t)
 
 }  // namespace
diff --git a/absl/strings/str_split_test.cc b/absl/strings/str_split_test.cc
index caa88277..a0085582 100644
--- a/absl/strings/str_split_test.cc
+++ b/absl/strings/str_split_test.cc
@@ -647,6 +647,11 @@ TEST(Split, StringDelimiter) {
   }
 }
 
+#if !defined(__cpp_char8_t)
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc++2a-compat"
+#endif
 TEST(Split, UTF8) {
   // Tests splitting utf8 strings and utf8 delimiters.
   std::string utf8_string = u8"\u03BA\u1F79\u03C3\u03BC\u03B5";
@@ -673,6 +678,10 @@ TEST(Split, UTF8) {
     EXPECT_THAT(v, ElementsAre("Foo", u8"h\u00E4llo", u8"th\u4E1Ere"));
   }
 }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+#endif  // !defined(__cpp_char8_t)
 
 TEST(Split, EmptyStringDelimiter) {
   {
diff --git a/absl/time/internal/cctz/src/zone_info_source.cc b/absl/time/internal/cctz/src/zone_info_source.cc
index bf2d2d2d..1bc16aec 100644
--- a/absl/time/internal/cctz/src/zone_info_source.cc
+++ b/absl/time/internal/cctz/src/zone_info_source.cc
@@ -54,7 +54,7 @@ ZoneInfoSourceFactory default_factory = DefaultFactory;
 #pragma comment( \
     linker,      \
     "/alternatename:?zone_info_source_factory@cctz_extension@time_internal@absl@@3P6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@5@ABV?$function@$$A6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@2@@Z@5@@ZA=?default_factory@cctz_extension@time_internal@absl@@3P6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@5@ABV?$function@$$A6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@2@@Z@5@@ZA")
-#elif defined(_M_IA_64) || defined(_M_AMD64)
+#elif defined(_M_IA_64) || defined(_M_AMD64) || defined(_M_ARM64)
 #pragma comment( \
     linker,      \
     "/alternatename:?zone_info_source_factory@cctz_extension@time_internal@absl@@3P6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@AEBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@5@AEBV?$function@$$A6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@AEBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@2@@Z@5@@ZEA=?default_factory@cctz_extension@time_internal@absl@@3P6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@AEBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@5@AEBV?$function@$$A6A?AV?$unique_ptr@VZoneInfoSource@cctz@time_internal@absl@@U?$default_delete@VZoneInfoSource@cctz@time_internal@absl@@@std@@@std@@AEBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@2@@Z@5@@ZEA")
diff --git a/absl/types/optional.h b/absl/types/optional.h
index fd185f35..d800ca68 100644
--- a/absl/types/optional.h
+++ b/absl/types/optional.h
@@ -295,7 +295,7 @@ class optional_data<T, false> : public optional_data_base<T> {
 
   optional_data() = default;
 
-  optional_data(const optional_data& rhs) {
+  optional_data(const optional_data& rhs) : optional_data_base<T>() {
     if (rhs.engaged_) {
       this->construct(rhs.data_);
     }
@@ -303,7 +303,8 @@ class optional_data<T, false> : public optional_data_base<T> {
 
   optional_data(optional_data&& rhs) noexcept(
       absl::default_allocator_is_nothrow::value ||
-      std::is_nothrow_move_constructible<T>::value) {
+      std::is_nothrow_move_constructible<T>::value)
+      : optional_data_base<T>() {
     if (rhs.engaged_) {
       this->construct(std::move(rhs.data_));
     }
diff --git a/absl/types/span_test.cc b/absl/types/span_test.cc
index bd739ff2..f4203b52 100644
--- a/absl/types/span_test.cc
+++ b/absl/types/span_test.cc
@@ -779,4 +779,19 @@ TEST(Span, SpanSize) {
   EXPECT_LE(sizeof(absl::Span<BigStruct>), 2 * sizeof(void*));
 }
 
+TEST(Span, Hash) {
+  int array[] = {1, 2, 3, 4};
+  int array2[] = {1, 2, 3};
+  using T = absl::Span<const int>;
+  EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(
+      {// Empties
+       T(), T(nullptr, 0), T(array, 0), T(array2, 0),
+       // Different array with same value
+       T(array, 3), T(array2), T({1, 2, 3}),
+       // Same array, but different length
+       T(array, 1), T(array, 2),
+       // Same length, but different array
+       T(array + 1, 2), T(array + 2, 2)}));
+}
+
 }  // namespace