Export of internal Abseil changes

--
30af50146f07d7afdb196abf235f44ec44ea6409 by Derek Mauro <dmauro@google.com>:

Update Abseil dependency versions

PiperOrigin-RevId: 374415690

--
6a241e9ea8ee201789bb66aadf9e1ca9cc23c5dc by Derek Mauro <dmauro@google.com>:

Fix the install test project, which is doing a mixed-mode build.
This manifests in failure with GCC 11, which defaults to C++17

Also explicitly reference python3 in the test script.
python2 is being removed by some Linux distros.

PiperOrigin-RevId: 374278107

--
42f85122407e799183880e0b2e2a71f6d35ee003 by Evan Brown <ezb@google.com>:

Use `capacity + Group::kWidth` control bytes instead of `capacity + Group::kWidth + 1`.

We don't use the extra byte - we only need the first `capacity` ones that are valid, the one sentinel byte and then `Group::kWidth - 1` cloned control bytes. For example, in `EmptyGroup()`, where capacity is 0, we use `Group::kWidth` control bytes.

We need to update set_ctrl() to only mirror `Group::kWidth - 1` bytes instead of `Group::kWidth` bytes.

Note: this doesn't actually save memory unless `alignof(value_type)` is one.

Also add/update related comments.

PiperOrigin-RevId: 374198589

--
5dcd09b2221bf23add583541769b476dac54e112 by Evan Brown <ezb@google.com>:

Improve b-tree value_comp() support.

- Don't expose internal adapted comparator functionality.
- Support value_comp() for maps using function pointer comparators.
- For maps, make value_compare's constructor and the member comparator be protected - [reference](https://en.cppreference.com/w/cpp/container/map/value_compare).

PiperOrigin-RevId: 373832649

--
d75819786ff5a06e1ed0c5c1e80b3b95ac49c83b by Evan Brown <ezb@google.com>:

Don't export adapted comparator functionality in key_comp().

PiperOrigin-RevId: 373651039
GitOrigin-RevId: 30af50146f07d7afdb196abf235f44ec44ea6409
Change-Id: I260480b0923cefeba81c543e2b7c34cacaa7d7c7

1 files changed, 8 insertions, 6 deletions

diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index b23e0078..669785e6 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -628,7 +628,9 @@ class raw_hash_set {
 
   static Layout MakeLayout(size_t capacity) {
     assert(IsValidCapacity(capacity));
-    return Layout(capacity + Group::kWidth + 1, capacity);
+    // The extra control bytes are for 1 sentinel byte followed by
+    // `Group::kWidth - 1` bytes that are cloned from the beginning.
+    return Layout(capacity + Group::kWidth, capacity);
   }
 
   using AllocTraits = absl::allocator_traits<allocator_type>;
@@ -1782,8 +1784,8 @@ class raw_hash_set {
     growth_left() = CapacityToGrowth(capacity()) - size_;
   }
 
-  // Sets the control byte, and if `i < Group::kWidth`, set the cloned byte at
-  // the end too.
+  // Sets the control byte, and if `i < Group::kWidth - 1`, set the cloned byte
+  // at the end too.
   void set_ctrl(size_t i, ctrl_t h) {
     assert(i < capacity_);
 
@@ -1794,8 +1796,8 @@ class raw_hash_set {
     }
 
     ctrl_[i] = h;
-    ctrl_[((i - Group::kWidth) & capacity_) + 1 +
-          ((Group::kWidth - 1) & capacity_)] = h;
+    constexpr size_t kClonedBytes = Group::kWidth - 1;
+    ctrl_[((i - kClonedBytes) & capacity_) + (kClonedBytes & capacity_)] = h;
   }
 
   size_t& growth_left() { return settings_.template get<0>(); }
@@ -1814,7 +1816,7 @@ class raw_hash_set {
   // TODO(alkis): Investigate removing some of these fields:
   // - ctrl/slots can be derived from each other
   // - size can be moved into the slot array
-  ctrl_t* ctrl_ = EmptyGroup();    // [(capacity + 1) * ctrl_t]
+  ctrl_t* ctrl_ = EmptyGroup();    // [(capacity + Group::kWidth) * ctrl_t]
   slot_type* slots_ = nullptr;     // [capacity * slot_type]
   size_t size_ = 0;                // number of full slots
   size_t capacity_ = 0;            // total number of slots