Export of internal Abseil changes

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5e45aadfb89e366dedd1fcad5034a76c5c10ad76 by James Y Knight <jyknight@google.com>:

Correct the conditions for std::{optional,variant,any} availability on Apple platforms.

Before XCode 12.5, the availability declarations incorrectly excluded one release on which the features were in fact available. This was corrected in https://github.com/llvm/llvm-project/commit/7fb40e1569dd66292b647f4501b85517e9247953

Unfortunately, we cannot simply switch abseil to the corrected versions, as that will cause build failures when using the older XCode toolchain. So, we check the version, and choose the correct set of versions for the toolchain in use.

PiperOrigin-RevId: 407667302

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376fa06cde048e536e9447336b27bebf598ed4ea by Greg Falcon <gfalcon@google.com>:

Cord implementation change: Add a new CordRepCrc node type.

This is an implementation detail that will allow storing expected CRCs alongside cord data.  This node is intended only to live at the top of Cord trees.

PiperOrigin-RevId: 407587140
GitOrigin-RevId: 5e45aadfb89e366dedd1fcad5034a76c5c10ad76
Change-Id: Iea3ca001c0cbb4deec8286b5581b30dc172a9918

1 files changed, 5 insertions, 5 deletions

diff --git a/absl/strings/internal/cord_rep_flat.h b/absl/strings/internal/cord_rep_flat.h
index 4d0f9886..62cf5840 100644
--- a/absl/strings/internal/cord_rep_flat.h
+++ b/absl/strings/internal/cord_rep_flat.h
@@ -44,11 +44,11 @@ static constexpr size_t kMaxFlatLength = kMaxFlatSize - kFlatOverhead;
 static constexpr size_t kMinFlatLength = kMinFlatSize - kFlatOverhead;
 
 constexpr uint8_t AllocatedSizeToTagUnchecked(size_t size) {
-  return static_cast<uint8_t>((size <= 1024) ? size / 8 + 1
-                                             : 129 + size / 32 - 1024 / 32);
+  return static_cast<uint8_t>((size <= 1024) ? size / 8 + 2
+                                             : 130 + size / 32 - 1024 / 32);
 }
 
-static_assert(kMinFlatSize / 8 + 1 >= FLAT, "");
+static_assert(kMinFlatSize / 8 + 2 >= FLAT, "");
 static_assert(AllocatedSizeToTagUnchecked(kMaxFlatSize) <= MAX_FLAT_TAG, "");
 
 // Helper functions for rounded div, and rounding to exact sizes.
@@ -73,7 +73,7 @@ inline uint8_t AllocatedSizeToTag(size_t size) {
 
 // Converts the provided tag to the corresponding allocated size
 constexpr size_t TagToAllocatedSize(uint8_t tag) {
-  return (tag <= 129) ? ((tag - 1) * 8) : (1024 + (tag - 129) * 32);
+  return (tag <= 130) ? ((tag - 2) * 8) : (1024 + (tag - 130) * 32);
 }
 
 // Converts the provided tag to the corresponding available data length
@@ -82,7 +82,7 @@ constexpr size_t TagToLength(uint8_t tag) {
 }
 
 // Enforce that kMaxFlatSize maps to a well-known exact tag value.
-static_assert(TagToAllocatedSize(225) == kMaxFlatSize, "Bad tag logic");
+static_assert(TagToAllocatedSize(226) == kMaxFlatSize, "Bad tag logic");
 
 struct CordRepFlat : public CordRep {
   // Creates a new flat node.