Export of internal Abseil changes

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c42a234e2c186bf697ce8d77e85628601fa514a6 by Abseil Team <absl-team@google.com>:

Enable the assertion in the iterator's operator++

PiperOrigin-RevId: 290134813

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f8c53ba8e9c5bb16bbcc1e412a5c2519c912c83e by Abseil Team <absl-team@google.com>:

Define operator== and operator!= for absl::{weak,strong}_equality and
absl::{partial,weak,strong}_ordering types themselves.

PiperOrigin-RevId: 290111564

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36bc574090cefad74a451719ce2761982647a51d by Tom Manshreck <shreck@google.com>:

Specify Time library flag formats

PiperOrigin-RevId: 289928010

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26dd40281add260baab2b60fec05dfb9c5304aaa by Mark Barolak <mbar@google.com>:

Delete an extraneous forward declaration of absl::Cord.

PiperOrigin-RevId: 289708481

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e60aea7f33554ff66d7699bb70e7af1d26323f1d by Abseil Team <absl-team@google.com>:

Release b-tree benchmarks.

PiperOrigin-RevId: 289654429

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660aa83fa000d4bae072b2d1c790f81d0939bc7e by Greg Falcon <gfalcon@google.com>:

Use https links.

Import of https://github.com/abseil/abseil-cpp/pull/586

PiperOrigin-RevId: 289479559

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0611ea4482dcf23d6b0a0389fe041eeb9052449a by Derek Mauro <dmauro@google.com>:

Removes the static initializer for LookupTables<absl::uint128>::kVmaxOverBase

Uses template specialization to hard code the resulting array.

Static initializers are problematic for a number of reasons. Not only
are they responsible for the static initialization order fiasco, but
they are in the critical path during program startup. For these
reasons, the Google C++ style guide strongly discourages them (and
forbids them when they are not trivially destructible), and Chromium
even has a test forbidding them.

https://google.github.io/styleguide/cppguide.html#Static_and_Global_Variables
https://chromium.googlesource.com/chromium/src.git/+/master/docs/static_initializers.md
http://neugierig.org/software/chromium/notes/2011/08/static-initializers.html

PiperOrigin-RevId: 289458677

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c869362f6bb7a872314f74750d38d81bdaa73f95 by Greg Falcon <gfalcon@google.com>:

Step 2 of 2 to fix our CCTZ fork to respect inline namespaces.

Re-import of CCTZ from GitHub, applying new changes to honor Abseil's optional inline namespace in MSVC.

PiperOrigin-RevId: 289454407

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fdb3474d76c2ee0371ccdf7593a78137c03a3f58 by Greg Falcon <gfalcon@google.com>:

Step 1 of 2 to fix our CCTZ fork to respect inline namespaces.

CCTZ uses a linker flag to simulate weak symbol support in MSVC.  This takes the form of a #pragma that includes the mangled names of two types: the symbol to treat as weak, and the symbol to use as its default value if no override is provided.

When Abseil is configured to use inline namespaces, the mangled names of these symbols change, and the pragma should change to reflect that.  Fortunately for us, MSVC name mangling is simple enough that we can generate the needed string literals in the preprocessor.

This CL introduces the new macros; the uses will be introduced in a follow-up CL.

PiperOrigin-RevId: 289435599

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5f152cc36f008acb9ab78f30b5efa40ebaf2754b by Matt Kulukundis <kfm@google.com>:

Improve documentation for lazy_emplace

PiperOrigin-RevId: 289333112
GitOrigin-RevId: c42a234e2c186bf697ce8d77e85628601fa514a6
Change-Id: I139ce6c7044a70d083af53e428bcb987f0fd88c6

1 files changed, 50 insertions, 2 deletions

diff --git a/absl/strings/numbers.cc b/absl/strings/numbers.cc
index caab463161eb..a0e5a7fd4e7d 100644
--- a/absl/strings/numbers.cc
+++ b/absl/strings/numbers.cc
@@ -30,6 +30,7 @@
 #include <memory>
 #include <utility>
 
+#include "absl/base/attributes.h"
 #include "absl/base/internal/bits.h"
 #include "absl/base/internal/raw_logging.h"
 #include "absl/strings/ascii.h"
@@ -719,8 +720,8 @@ inline bool safe_parse_sign_and_base(absl::string_view* text /*inout*/,
 // commonly used bases.
 template <typename IntType>
 struct LookupTables {
-  static const IntType kVmaxOverBase[];
-  static const IntType kVminOverBase[];
+  ABSL_CONST_INIT static const IntType kVmaxOverBase[];
+  ABSL_CONST_INIT static const IntType kVminOverBase[];
 };
 
 // An array initializer macro for X/base where base in [0, 36].
@@ -735,6 +736,49 @@ struct LookupTables {
         X / 35, X / 36,                                                   \
   }
 
+// uint128& operator/=(uint128) is not constexpr, so hardcode the resulting
+// array to avoid a static initializer.
+template <>
+const uint128 LookupTables<uint128>::kVmaxOverBase[] = {
+    0,
+    0,
+    MakeUint128(9223372036854775807u, 18446744073709551615u),
+    MakeUint128(6148914691236517205u, 6148914691236517205u),
+    MakeUint128(4611686018427387903u, 18446744073709551615u),
+    MakeUint128(3689348814741910323u, 3689348814741910323u),
+    MakeUint128(3074457345618258602u, 12297829382473034410u),
+    MakeUint128(2635249153387078802u, 5270498306774157604u),
+    MakeUint128(2305843009213693951u, 18446744073709551615u),
+    MakeUint128(2049638230412172401u, 14347467612885206812u),
+    MakeUint128(1844674407370955161u, 11068046444225730969u),
+    MakeUint128(1676976733973595601u, 8384883669867978007u),
+    MakeUint128(1537228672809129301u, 6148914691236517205u),
+    MakeUint128(1418980313362273201u, 4256940940086819603u),
+    MakeUint128(1317624576693539401u, 2635249153387078802u),
+    MakeUint128(1229782938247303441u, 1229782938247303441u),
+    MakeUint128(1152921504606846975u, 18446744073709551615u),
+    MakeUint128(1085102592571150095u, 1085102592571150095u),
+    MakeUint128(1024819115206086200u, 16397105843297379214u),
+    MakeUint128(970881267037344821u, 16504981539634861972u),
+    MakeUint128(922337203685477580u, 14757395258967641292u),
+    MakeUint128(878416384462359600u, 14054662151397753612u),
+    MakeUint128(838488366986797800u, 13415813871788764811u),
+    MakeUint128(802032351030850070u, 4812194106185100421u),
+    MakeUint128(768614336404564650u, 12297829382473034410u),
+    MakeUint128(737869762948382064u, 11805916207174113034u),
+    MakeUint128(709490156681136600u, 11351842506898185609u),
+    MakeUint128(683212743470724133u, 17080318586768103348u),
+    MakeUint128(658812288346769700u, 10540996613548315209u),
+    MakeUint128(636094623231363848u, 15266270957552732371u),
+    MakeUint128(614891469123651720u, 9838263505978427528u),
+    MakeUint128(595056260442243600u, 9520900167075897608u),
+    MakeUint128(576460752303423487u, 18446744073709551615u),
+    MakeUint128(558992244657865200u, 8943875914525843207u),
+    MakeUint128(542551296285575047u, 9765923333140350855u),
+    MakeUint128(527049830677415760u, 8432797290838652167u),
+    MakeUint128(512409557603043100u, 8198552921648689607u),
+};
+
 template <typename IntType>
 const IntType LookupTables<IntType>::kVmaxOverBase[] =
     X_OVER_BASE_INITIALIZER(std::numeric_limits<IntType>::max());
@@ -754,6 +798,8 @@ inline bool safe_parse_positive_int(absl::string_view text, int base,
   assert(base >= 0);
   assert(vmax >= static_cast<IntType>(base));
   const IntType vmax_over_base = LookupTables<IntType>::kVmaxOverBase[base];
+  assert(base < 2 ||
+         std::numeric_limits<IntType>::max() / base == vmax_over_base);
   const char* start = text.data();
   const char* end = start + text.size();
   // loop over digits
@@ -787,6 +833,8 @@ inline bool safe_parse_negative_int(absl::string_view text, int base,
   assert(vmin < 0);
   assert(vmin <= 0 - base);
   IntType vmin_over_base = LookupTables<IntType>::kVminOverBase[base];
+  assert(base < 2 ||
+         std::numeric_limits<IntType>::min() / base == vmin_over_base);
   // 2003 c++ standard [expr.mul]
   // "... the sign of the remainder is implementation-defined."
   // Although (vmin/base)*base + vmin%base is always vmin.