Export of internal Abseil changes.

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eca34da4ccb7bb6a580f1364dff9ca053418fa3b by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 214305433

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35393bdd21a87c4286f945fd34dda93afc4e0cd6 by Abseil Team <absl-team@google.com>:

Move some implementation details of string_view around to facilitate compiling on NVCC.

Abseil does not officially support NVCC as a reminder.

PiperOrigin-RevId: 214184876

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61846cab9ab9476a4676ecade7173f68978cd038 by Jorg Brown <jorg@google.com>:

Move the initialization values for constants back to their declaration.

PiperOrigin-RevId: 214135927

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7ac7df6c5f78f2faf419268c04618b936cb26065 by Abseil Team <absl-team@google.com>:

Performance improvements on format parser.

PiperOrigin-RevId: 214032366

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90b4c0cf20e9feaa257a7ece40adaf7db40a60a7 by Xiaoyi Zhang <zhangxy@google.com>:

Add static_assert check to absl::visit to make sure all overloads of the visitor return the same type, as required by the C++ standard.

PiperOrigin-RevId: 213677001

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787995342101b4c181291cde9ecea3048536e4bd by Abseil Team <absl-team@google.com>:

Update comment to indicate finite durations are less than InfiniteDuration.

PiperOrigin-RevId: 213660328

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d78f0dce7cc31218807e96d93b9e8513b6c80b24 by Jon Cohen <cohenjon@google.com>:

s/invariant/contract in the exceptions safety testing framework.  This is a better term as these can be type invariants or function post conditions.  They also are very similar ground as to what is covered by c++20 Contracts (and could even be replaced by them.

PiperOrigin-RevId: 213631019

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0b3ff1a640de9a7391a6c233568802cf86245b0e by Abseil Team <absl-team@google.com>:

Add noinline attribute for GetStackTrace/GetStackFrames/... so the skipped frames will not change because of inlining difference.

PiperOrigin-RevId: 213009637
GitOrigin-RevId: eca34da4ccb7bb6a580f1364dff9ca053418fa3b
Change-Id: Iff1022fd24e440fcbdf3c4ab2a915ca8954daa31

absl/strings/string_view.h

@@ -173,8 +173,19 @@ class string_view {
   // Implicit constructor of a `string_view` from nul-terminated `str`. When
   // accepting possibly null strings, use `absl::NullSafeStringView(str)`
   // instead (see below).
+#if ABSL_HAVE_BUILTIN(__builtin_strlen) || \
+    (defined(__GNUC__) && !defined(__clang__))
+  // GCC has __builtin_strlen according to
+  // https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Other-Builtins.html, but
+  // ABSL_HAVE_BUILTIN doesn't detect that, so we use the extra checks above.
+  // __builtin_strlen is constexpr.
   constexpr string_view(const char* str)  // NOLINT(runtime/explicit)
-      : ptr_(str), length_(CheckLengthInternal(StrLenInternal(str))) {}
+      : ptr_(str),
+        length_(CheckLengthInternal(str ? __builtin_strlen(str) : 0)) {}
+#else
+  constexpr string_view(const char* str)  // NOLINT(runtime/explicit)
+      : ptr_(str), length_(CheckLengthInternal(str ? strlen(str) : 0)) {}
+#endif
 
   // Implicit constructor of a `string_view` from a `const char*` and length.
   constexpr string_view(const char* data, size_type len)
@@ -481,22 +492,6 @@ class string_view {
   static constexpr size_type kMaxSize =
       std::numeric_limits<difference_type>::max();
 
-  // check whether __builtin_strlen is provided by the compiler.
-  // GCC doesn't have __has_builtin()
-  // (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66970),
-  // but has __builtin_strlen according to
-  // https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Other-Builtins.html.
-#if ABSL_HAVE_BUILTIN(__builtin_strlen) || \
-    (defined(__GNUC__) && !defined(__clang__))
-  static constexpr size_type StrLenInternal(const char* str) {
-    return str ? __builtin_strlen(str) : 0;
-  }
-#else
-  static constexpr size_type StrLenInternal(const char* str) {
-    return str ? strlen(str) : 0;
-  }
-#endif
-
   static constexpr size_type CheckLengthInternal(size_type len) {
     return ABSL_ASSERT(len <= kMaxSize), len;
   }