Export of internal Abseil changes.

--
7fb969986d7d5a1b30233a94ae7ea29e1abf8937 by Greg Falcon <gfalcon@google.com>:

Fix whitespace in str_join.h.

PiperOrigin-RevId: 208082852

--
85428003a8a29fbcd92c0b48708a69460eeb0e8f by Abseil Team <absl-team@google.com>:

Add missing back-ticks to the comments.

PiperOrigin-RevId: 207985417

--
0bbac248d5649ac1d7bc71ff1025a11332fb2026 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 207927484

--
f587324b99570b403b4626fb03fce16f0d950b05 by Abseil Team <absl-team@google.com>:

Update BaseCountedInstance to have comparison operators and allow them to be tracked by InstanceTracker.

PiperOrigin-RevId: 207919218

--
d7f410e4f15328412941f16e25ba3735d5bdfda6 by Derek Mauro <dmauro@google.com>:

Internal import of GitHub PR #153
Removed "warning treated as error" flag from MSVC

PiperOrigin-RevId: 207908806

--
59eefc78f8571ffc51cb636894015ce2580508d7 by Abseil Team <absl-team@google.com>:

Fix namespace references in examples from 'std::' to 'absl::'.

PiperOrigin-RevId: 207895230

--
151df17b6544222e29913b034a1296c0e14374d5 by Abseil Team <absl-team@google.com>:

Internal Change

PiperOrigin-RevId: 207894949
GitOrigin-RevId: 7fb969986d7d5a1b30233a94ae7ea29e1abf8937
Change-Id: I00097afbe9610ddb3f2330a2a86dcffde7bb6675

12 files changed, 103 insertions, 10 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 06d092ebdfa8..b0f4b680df5e 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -19,6 +19,7 @@ load(
     "ABSL_DEFAULT_COPTS",
     "ABSL_TEST_COPTS",
     "ABSL_EXCEPTIONS_FLAG",
+    "ABSL_EXCEPTIONS_FLAG_LINKOPTS",
 )
 
 package(default_visibility = ["//visibility:public"])
@@ -179,6 +180,7 @@ cc_library(
     srcs = ["internal/throw_delegate.cc"],
     hdrs = ["internal/throw_delegate.h"],
     copts = ABSL_DEFAULT_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     visibility = [
         "//absl:__subpackages__",
     ],
@@ -193,6 +195,7 @@ cc_test(
     name = "throw_delegate_test",
     srcs = ["throw_delegate_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":throw_delegate",
         "@com_google_googletest//:gtest_main",
@@ -225,6 +228,7 @@ cc_library(
     srcs = ["internal/exception_safety_testing.cc"],
     hdrs = ["internal/exception_safety_testing.h"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":base",
         ":config",
@@ -241,6 +245,7 @@ cc_test(
     name = "exception_safety_testing_test",
     srcs = ["exception_safety_testing_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":exception_safety_testing",
         "//absl/memory",
diff --git a/absl/container/BUILD.bazel b/absl/container/BUILD.bazel
index 6d5c958f382b..7b5f52bc059e 100644
--- a/absl/container/BUILD.bazel
+++ b/absl/container/BUILD.bazel
@@ -19,6 +19,7 @@ load(
     "ABSL_DEFAULT_COPTS",
     "ABSL_TEST_COPTS",
     "ABSL_EXCEPTIONS_FLAG",
+    "ABSL_EXCEPTIONS_FLAG_LINKOPTS",
 )
 
 package(default_visibility = ["//visibility:public"])
@@ -62,6 +63,7 @@ cc_test(
     name = "fixed_array_test",
     srcs = ["fixed_array_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":fixed_array",
         "//absl/base:exception_testing",
@@ -86,6 +88,7 @@ cc_test(
     name = "fixed_array_exception_safety_test",
     srcs = ["fixed_array_exception_safety_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":fixed_array",
         "//absl/base:exception_safety_testing",
@@ -120,6 +123,7 @@ cc_test(
     name = "inlined_vector_test",
     srcs = ["inlined_vector_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":inlined_vector",
         ":test_instance_tracker",
diff --git a/absl/container/internal/test_instance_tracker.cc b/absl/container/internal/test_instance_tracker.cc
index fe00aca8fb98..b18e0bb7a1ea 100644
--- a/absl/container/internal/test_instance_tracker.cc
+++ b/absl/container/internal/test_instance_tracker.cc
@@ -21,6 +21,7 @@ int BaseCountedInstance::num_live_instances_ = 0;
 int BaseCountedInstance::num_moves_ = 0;
 int BaseCountedInstance::num_copies_ = 0;
 int BaseCountedInstance::num_swaps_ = 0;
+int BaseCountedInstance::num_comparisons_ = 0;
 
 }  // namespace test_internal
 }  // namespace absl
diff --git a/absl/container/internal/test_instance_tracker.h b/absl/container/internal/test_instance_tracker.h
index cf8f3a531e62..ec45f574037f 100644
--- a/absl/container/internal/test_instance_tracker.h
+++ b/absl/container/internal/test_instance_tracker.h
@@ -22,8 +22,8 @@ namespace absl {
 namespace test_internal {
 
 // A type that counts number of occurences of the type, the live occurrences of
-// the type, as well as the number of copies, moves, and swaps that have
-// occurred on the type. This is used as a base class for the copyable,
+// the type, as well as the number of copies, moves, swaps, and comparisons that
+// have occurred on the type. This is used as a base class for the copyable,
 // copyable+movable, and movable types below that are used in actual tests. Use
 // InstanceTracker in tests to track the number of instances.
 class BaseCountedInstance {
@@ -66,6 +66,36 @@ class BaseCountedInstance {
     return *this;
   }
 
+  bool operator==(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ == x.value_;
+  }
+
+  bool operator!=(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ != x.value_;
+  }
+
+  bool operator<(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ < x.value_;
+  }
+
+  bool operator>(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ > x.value_;
+  }
+
+  bool operator<=(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ <= x.value_;
+  }
+
+  bool operator>=(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ >= x.value_;
+  }
+
   int value() const {
     if (!is_live_) std::abort();
     return value_;
@@ -108,6 +138,9 @@ class BaseCountedInstance {
 
   // Number of times that BaseCountedInstance objects were swapped.
   static int num_swaps_;
+
+  // Number of times that BaseCountedInstance objects were compared.
+  static int num_comparisons_;
 };
 
 // Helper to track the BaseCountedInstance instance counters. Expects that the
@@ -152,13 +185,21 @@ class InstanceTracker {
   // construction or the last call to ResetCopiesMovesSwaps().
   int swaps() const { return BaseCountedInstance::num_swaps_ - start_swaps_; }
 
-  // Resets the base values for moves, copies and swaps to the current values,
-  // so that subsequent Get*() calls for moves, copies and swaps will compare to
-  // the situation at the point of this call.
+  // Returns the number of comparisons on BaseCountedInstance objects since
+  // construction or the last call to ResetCopiesMovesSwaps().
+  int comparisons() const {
+    return BaseCountedInstance::num_comparisons_ - start_comparisons_;
+  }
+
+  // Resets the base values for moves, copies, comparisons, and swaps to the
+  // current values, so that subsequent Get*() calls for moves, copies,
+  // comparisons, and swaps will compare to the situation at the point of this
+  // call.
   void ResetCopiesMovesSwaps() {
     start_moves_ = BaseCountedInstance::num_moves_;
     start_copies_ = BaseCountedInstance::num_copies_;
     start_swaps_ = BaseCountedInstance::num_swaps_;
+    start_comparisons_ = BaseCountedInstance::num_comparisons_;
   }
 
  private:
@@ -167,6 +208,7 @@ class InstanceTracker {
   int start_moves_;
   int start_copies_;
   int start_swaps_;
+  int start_comparisons_;
 };
 
 // Copyable, not movable.
diff --git a/absl/container/internal/test_instance_tracker_test.cc b/absl/container/internal/test_instance_tracker_test.cc
index 9efb6771cf08..0ae57636df21 100644
--- a/absl/container/internal/test_instance_tracker_test.cc
+++ b/absl/container/internal/test_instance_tracker_test.cc
@@ -157,4 +157,26 @@ TEST(TestInstanceTracker, ExistingInstances) {
   EXPECT_EQ(1, tracker.moves());
 }
 
+TEST(TestInstanceTracker, Comparisons) {
+  InstanceTracker tracker;
+  MovableOnlyInstance one(1), two(2);
+
+  EXPECT_EQ(0, tracker.comparisons());
+  EXPECT_FALSE(one == two);
+  EXPECT_EQ(1, tracker.comparisons());
+  EXPECT_TRUE(one != two);
+  EXPECT_EQ(2, tracker.comparisons());
+  EXPECT_TRUE(one < two);
+  EXPECT_EQ(3, tracker.comparisons());
+  EXPECT_FALSE(one > two);
+  EXPECT_EQ(4, tracker.comparisons());
+  EXPECT_TRUE(one <= two);
+  EXPECT_EQ(5, tracker.comparisons());
+  EXPECT_FALSE(one >= two);
+  EXPECT_EQ(6, tracker.comparisons());
+
+  tracker.ResetCopiesMovesSwaps();
+  EXPECT_EQ(0, tracker.comparisons());
+}
+
 }  // namespace
diff --git a/absl/copts.bzl b/absl/copts.bzl
index 259de30c2358..e4b425b08e71 100644
--- a/absl/copts.bzl
+++ b/absl/copts.bzl
@@ -35,7 +35,6 @@ GCC_TEST_FLAGS = [
 # Docs on groups of flags is preceded by ###.
 
 LLVM_FLAGS = [
-    # All warnings are treated as errors by implicit -Werror flag
     "-Wall",
     "-Wextra",
     "-Weverything",
@@ -151,3 +150,7 @@ ABSL_EXCEPTIONS_FLAG = select({
     "//absl:windows": ["/U_HAS_EXCEPTIONS", "/D_HAS_EXCEPTIONS=1", "/EHsc"],
     "//conditions:default": ["-fexceptions"],
 })
+
+ABSL_EXCEPTIONS_FLAG_LINKOPTS = select({
+    "//conditions:default": [],
+})
diff --git a/absl/memory/BUILD.bazel b/absl/memory/BUILD.bazel
index 46f47b12bb2a..89a312eac4b1 100644
--- a/absl/memory/BUILD.bazel
+++ b/absl/memory/BUILD.bazel
@@ -19,6 +19,7 @@ load(
     "ABSL_DEFAULT_COPTS",
     "ABSL_TEST_COPTS",
     "ABSL_EXCEPTIONS_FLAG",
+    "ABSL_EXCEPTIONS_FLAG_LINKOPTS",
 )
 
 package(default_visibility = ["//visibility:public"])
@@ -53,6 +54,7 @@ cc_test(
         "memory_exception_safety_test.cc",
     ],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":memory",
         "//absl/base:exception_safety_testing",
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index 3a5f1332cda0..6caf8b975903 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -19,6 +19,7 @@ load(
     "ABSL_DEFAULT_COPTS",
     "ABSL_TEST_COPTS",
     "ABSL_EXCEPTIONS_FLAG",
+    "ABSL_EXCEPTIONS_FLAG_LINKOPTS",
 )
 
 package(
@@ -237,6 +238,7 @@ cc_test(
     size = "small",
     srcs = ["string_view_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     visibility = ["//visibility:private"],
     deps = [
         ":strings",
diff --git a/absl/strings/str_join.h b/absl/strings/str_join.h
index bd4d0e1d9324..b0680e83feb5 100644
--- a/absl/strings/str_join.h
+++ b/absl/strings/str_join.h
@@ -52,6 +52,7 @@
 #include <iterator>
 #include <string>
 #include <tuple>
+#include <type_traits>
 #include <utility>
 
 #include "absl/base/macros.h"
diff --git a/absl/strings/string_view.h b/absl/strings/string_view.h
index 1537a3f84283..96101463125b 100644
--- a/absl/strings/string_view.h
+++ b/absl/strings/string_view.h
@@ -340,7 +340,7 @@ class string_view {
   //
   // Returns a "substring" of the `string_view` (at offset `pos` and length
   // `n`) as another string_view. This function throws `std::out_of_bounds` if
-  // `pos > size'.
+  // `pos > size`.
   string_view substr(size_type pos, size_type n = npos) const {
     if (ABSL_PREDICT_FALSE(pos > length_))
       base_internal::ThrowStdOutOfRange("absl::string_view::substr");
@@ -351,7 +351,7 @@ class string_view {
   // string_view::compare()
   //
   // Performs a lexicographical comparison between the `string_view` and
-  // another `absl::string_view), returning -1 if `this` is less than, 0 if
+  // another `absl::string_view`, returning -1 if `this` is less than, 0 if
   // `this` is equal to, and 1 if `this` is greater than the passed std::string
   // view. Note that in the case of data equality, a further comparison is made
   // on the respective sizes of the two `string_view`s to determine which is
diff --git a/absl/types/BUILD.bazel b/absl/types/BUILD.bazel
index 096c119e638c..7841a97d985a 100644
--- a/absl/types/BUILD.bazel
+++ b/absl/types/BUILD.bazel
@@ -19,6 +19,7 @@ load(
     "ABSL_DEFAULT_COPTS",
     "ABSL_TEST_COPTS",
     "ABSL_EXCEPTIONS_FLAG",
+    "ABSL_EXCEPTIONS_FLAG_LINKOPTS",
 )
 
 package(default_visibility = ["//visibility:public"])
@@ -55,6 +56,7 @@ cc_library(
         "bad_any_cast.h",
     ],
     copts = ABSL_EXCEPTIONS_FLAG + ABSL_DEFAULT_COPTS,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     visibility = ["//visibility:private"],
     deps = [
         "//absl/base",
@@ -69,6 +71,7 @@ cc_test(
         "any_test.cc",
     ],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":any",
         "//absl/base",
@@ -100,6 +103,7 @@ cc_test(
     name = "any_exception_safety_test",
     srcs = ["any_exception_safety_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":any",
         "//absl/base:exception_safety_testing",
@@ -124,6 +128,7 @@ cc_test(
     size = "small",
     srcs = ["span_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":span",
         "//absl/base:config",
@@ -172,6 +177,7 @@ cc_library(
     srcs = ["bad_optional_access.cc"],
     hdrs = ["bad_optional_access.h"],
     copts = ABSL_DEFAULT_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         "//absl/base",
         "//absl/base:config",
@@ -183,6 +189,7 @@ cc_library(
     srcs = ["bad_variant_access.cc"],
     hdrs = ["bad_variant_access.h"],
     copts = ABSL_EXCEPTIONS_FLAG + ABSL_DEFAULT_COPTS,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         "//absl/base",
         "//absl/base:config",
@@ -196,6 +203,7 @@ cc_test(
         "optional_test.cc",
     ],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":optional",
         "//absl/base",
@@ -212,6 +220,7 @@ cc_test(
         "optional_exception_safety_test.cc",
     ],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":optional",
         "//absl/base:exception_safety_testing",
@@ -239,6 +248,7 @@ cc_test(
     size = "small",
     srcs = ["variant_test.cc"],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":variant",
         "//absl/base:config",
@@ -271,6 +281,7 @@ cc_test(
         "variant_exception_safety_test.cc",
     ],
     copts = ABSL_TEST_COPTS + ABSL_EXCEPTIONS_FLAG,
+    linkopts = ABSL_EXCEPTIONS_FLAG_LINKOPTS,
     deps = [
         ":variant",
         "//absl/base:exception_safety_testing",
diff --git a/absl/types/variant.h b/absl/types/variant.h
index 17e0634de037..2f78722f8b7c 100644
--- a/absl/types/variant.h
+++ b/absl/types/variant.h
@@ -414,9 +414,9 @@ constexpr absl::add_pointer_t<const T> get_if(
 //   };
 //
 //   // Declare our variant, and call `absl::visit()` on it.
-//   std::variant<int, std::string> foo = std::string("foo");
+//   absl::variant<int, std::string> foo = std::string("foo");
 //   GetVariant visitor;
-//   std::visit(visitor, foo);  // Prints `The variant's value is: foo'
+//   absl::visit(visitor, foo);  // Prints `The variant's value is: foo'
 template <typename Visitor, typename... Variants>
 variant_internal::VisitResult<Visitor, Variants...> visit(Visitor&& vis,
                                                           Variants&&... vars) {