Use Layout::WithStaticSizes in SerialArenaChunk to improve performance of Layout computations.

PiperOrigin-RevId: 688155852

.github/workflows/test_cpp.yml

@@ -173,7 +173,7 @@ jobs:
         if: ${{ !matrix.continuous-only || inputs.continuous-run }}
         uses: protocolbuffers/protobuf-ci/docker@v3
         with:
-          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/cmake:3.16.9-f39fc8b4e244fe5cd4c7138d0b6959a52b46ca48
+          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/cmake:3.16.9-d9624f2aa83cba3eaf906f751d75b36aacb9aa82
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
           command: >-
             /test.sh ${{ matrix.flags}} ${{ env.SCCACHE_CMAKE_FLAGS }}
@@ -212,7 +212,7 @@ jobs:
         uses: protocolbuffers/protobuf-ci/docker@v3
         if: ${{ !matrix.continuous-only || inputs.continuous-run }}
         with:
-          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/cmake:3.16.9-f39fc8b4e244fe5cd4c7138d0b6959a52b46ca48
+          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/cmake:3.16.9-d9624f2aa83cba3eaf906f751d75b36aacb9aa82
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
           command: >-
             /install.sh -DCMAKE_CXX_STANDARD=17 ${{ env.SCCACHE_CMAKE_FLAGS }}
@@ -248,7 +248,7 @@ jobs:
         if: ${{ inputs.continuous-run }}
         uses: protocolbuffers/protobuf-ci/docker@v3
         with:
-          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/cmake:3.16.9-f39fc8b4e244fe5cd4c7138d0b6959a52b46ca48
+          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/cmake:3.16.9-d9624f2aa83cba3eaf906f751d75b36aacb9aa82
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
           command: >-
             /install.sh -DCMAKE_CXX_STANDARD=17 ${{ env.SCCACHE_CMAKE_FLAGS }}

protobuf_deps.bzl

@@ -62,8 +62,6 @@ def protobuf_deps():
         _github_archive(
             name = "com_google_absl",
             repo = "https://github.com/abseil/abseil-cpp",
-            # TODO: use Layout::WithStaticSizes in SerialArenaChunk when we update
-            # abseil to new release.
             commit = "4447c7562e3bc702ade25105912dce503f0c4010",  # Abseil LTS 20240722.0
             sha256 = "d8342ad77aa9e16103c486b615460c24a695a1f04cdb760eb02fef780df99759",
         )

src/google/protobuf/arena.cc

@@ -507,7 +507,8 @@ class ThreadSafeArena::SerialArenaChunk {
   constexpr static int kArenas = 2;
 
   using layout_type = absl::container_internal::Layout<
-      SerialArenaChunkHeader, std::atomic<void*>, std::atomic<SerialArena*>>;
+      SerialArenaChunkHeader, std::atomic<void*>,
+      std::atomic<SerialArena*>>::WithStaticSizes</*header*/ 1>;
 
   const char* ptr() const { return reinterpret_cast<const char*>(this); }
   char* ptr() { return reinterpret_cast<char*>(this); }
@@ -529,7 +530,7 @@ class ThreadSafeArena::SerialArenaChunk {
   }
 
   constexpr static layout_type Layout(size_t n) {
-    return layout_type(/*header*/ 1, /*ids*/ n, /*arenas*/ n);
+    return layout_type(/*ids*/ n, /*arenas*/ n);
   }
   layout_type Layout() const { return Layout(capacity()); }
 };