Export of internal Abseil changes

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dab5caab05d89d03066ef92584660688595a3aaf by Mark Barolak <[email protected]>:

Add absl::Status and absl::StatusOr to absl/README.md

Import of #863

PiperOrigin-RevId: 347857368

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1ca3c7a96417cd6e6d62f4dc36fd5ddaa61cfa20 by Chris Kennelly <[email protected]>:

Leverage integer power-of-2 functions and bit counting library in Abseil.

PiperOrigin-RevId: 347816486

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e5cbe05879fd65dce7875e2e0105331a1615d89b by Chris Kennelly <[email protected]>:

Mitigate narrowing warning on MSVC.

If sizeof(x) <= sizeof(uint32_t), no truncation occurs when casting to
uint32_t, but the compiler cannot always determine this.

PiperOrigin-RevId: 347696526

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079dff64cb175d282d9e22dfb4a522199ffdae2e by Benjamin Barenblat <[email protected]>:

Avoid libgcc -NaN narrowing bug

When testing -NaN parsing, avoid narrowing -NaN from double to float.
This avoids a bug in libgcc
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98251).

PiperOrigin-RevId: 347654751

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2e78a7634865aeef6765e1f447e96cf8d9985059 by Chris Kennelly <[email protected]>:

Mark popcount helpers as inline.

These are conditionally constexpr, so we need to add inline to cover the
non-constexpr builds to avoid ODR violations.

PiperOrigin-RevId: 347620138

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437fbb363aea1654179f102dcdd607ec33c1af1e by Chris Kennelly <[email protected]>:

Use explicit narrowing cast.

This is never invoked in practice, but compilers with -Wimplicit-int-conversion
may trigger when sizeof(T) > sizeof(uint16_t) prior to determining this never
runs.

PiperOrigin-RevId: 347609857
GitOrigin-RevId: dab5caab05d89d03066ef92584660688595a3aaf
Change-Id: I6296ddffe7ec646f8ce121138f21e1e85a2cff4b

CMake/AbseilDll.cmake

@@ -10,7 +10,6 @@ set(ABSL_INTERNAL_DLL_FILES
   "base/const_init.h"
   "base/dynamic_annotations.h"
   "base/internal/atomic_hook.h"
-  "base/internal/bits.h"
   "base/internal/cycleclock.cc"
   "base/internal/cycleclock.h"
   "base/internal/direct_mmap.h"

README.md

@@ -80,8 +80,8 @@ Abseil contains the following C++ library components:
 * [`numeric`](absl/numeric/)
   <br /> The `numeric` library contains C++11-compatible 128-bit integers.
 * [`status`](absl/status/)
-  <br /> The `status` library is used within Google for error handling utilizing the 
-  following two main abstractions: `absl::Status` and `absl::StatusOr<T>`. 
+  <br /> The `status` contains abstractions for error handling, specifically
+  `absl::Status` and `absl::StatusOr<T>`.
 * [`strings`](absl/strings/)
   <br /> The `strings` library contains a variety of strings routines and
   utilities, including a C++11-compatible version of the C++17

absl/base/BUILD.bazel

@@ -586,31 +586,6 @@ cc_test(
     ],
 )
 
-cc_library(
-    name = "bits",
-    hdrs = ["internal/bits.h"],
-    linkopts = ABSL_DEFAULT_LINKOPTS,
-    visibility = [
-        "//absl:__subpackages__",
-    ],
-    deps = [
-        ":config",
-        ":core_headers",
-    ],
-)
-
-cc_test(
-    name = "bits_test",
-    size = "small",
-    srcs = ["internal/bits_test.cc"],
-    copts = ABSL_TEST_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
-    deps = [
-        ":bits",
-        "@com_google_googletest//:gtest_main",
-    ],
-)
-
 cc_library(
     name = "exponential_biased",
     srcs = ["internal/exponential_biased.cc"],

absl/base/CMakeLists.txt

@@ -518,30 +518,6 @@ absl_cc_test(
     gtest_main
 )
 
-absl_cc_library(
-  NAME
-    internal_bits
-  HDRS
-    "internal/bits.h"
-  COPTS
-    ${ABSL_DEFAULT_COPTS}
-  DEPS
-    absl::config
-    absl::core_headers
-)
-
-absl_cc_test(
-  NAME
-    internal_bits_test
-  SRCS
-    "internal/bits_test.cc"
-  COPTS
-    ${ABSL_TEST_COPTS}
-  DEPS
-    absl::internal_bits
-    gtest_main
-)
-
 absl_cc_library(
   NAME
     exponential_biased