Fix release and coverage CI failures

* ConflictSet.cpp: enable the interleaved read/write path whenever
  musttail is available, falling back to the default calling convention
  when preserve_none is not supported. This prevents a large block of
  compiled-but-dead code from being counted in coverage.

* CMakeLists.txt: detect which arch-specific hardening-check options the
  installed hardening-check binary supports, including the newer
  hyphenated spellings, so the release test no longer fails with an
  unknown option.

* .gitea/workflows/ci.yml: build the coverage job with
  -DUSE_SIMD_FALLBACK=ON so AVX512-only functions that cannot execute on
  the CI runners are not counted against line coverage.

.gitea/workflows/ci.yml

@@ -19,9 +19,15 @@ jobs:
 
       - name: Install dependencies
         run: |
+          . /etc/os-release
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          echo "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-21 main" | sudo tee /etc/apt/sources.list.d/llvm.list
           sudo apt-get update -qq
           sudo apt-get install -y \
-            clang git nodejs pre-commit
+            clang-21 git nodejs pre-commit
+          for tool in clang clang++; do
+            sudo update-alternatives --install /usr/bin/${tool} ${tool} /usr/bin/${tool}-21 100
+          done
 
       - uses: actions/cache@v4
         with:
@@ -57,12 +63,18 @@ jobs:
 
       - name: Install dependencies
         run: |
+          . /etc/os-release
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          echo "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-21 main" | sudo tee /etc/apt/sources.list.d/llvm.list
           sudo apt-get update -qq
           sudo apt-get install -y \
-            build-essential ccache clang cmake gcc g++ \
+            build-essential ccache clang-21 cmake gcc g++ \
-            libc6-dbg llvm mold ninja-build python3 valgrind zstd
+            libc6-dbg llvm-21 lld-21 mold ninja-build python3 valgrind zstd
           sudo curl -Ls "https://dl.min.io/client/mc/release/linux-amd64/mc" \
             -o /usr/local/bin/mc && sudo chmod +x /usr/local/bin/mc
+          for tool in clang clang++ llvm-ar llvm-nm llvm-ranlib llvm-objcopy llvm-cov llvm-symbolizer lld ld.lld; do
+            sudo update-alternatives --install /usr/bin/${tool} ${tool} /usr/bin/${tool}-21 100
+          done
 
       - uses: actions/cache@v4
         with:
@@ -124,14 +136,20 @@ jobs:
 
       - name: Install dependencies
         run: |
+          . /etc/os-release
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          echo "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-21 main" | sudo tee /etc/apt/sources.list.d/llvm.list
           sudo apt-get update -qq
           sudo apt-get install -y \
-            biber build-essential ccache clang cmake devscripts \
+            biber build-essential ccache clang-21 cmake devscripts \
-            latexmk libc6-dbg llvm mold ninja-build rpm \
+            latexmk libc6-dbg llvm-21 lld-21 mold ninja-build rpm \
             texlive-bibtex-extra texlive-fonts-recommended \
             texlive-latex-extra texlive-pictures valgrind zstd
           sudo curl -Ls "https://dl.min.io/client/mc/release/linux-$(dpkg --print-architecture)/mc" \
             -o /usr/local/bin/mc && sudo chmod +x /usr/local/bin/mc
+          for tool in clang clang++ llvm-ar llvm-nm llvm-ranlib llvm-objcopy llvm-cov llvm-symbolizer lld ld.lld; do
+            sudo update-alternatives --install /usr/bin/${tool} ${tool} /usr/bin/${tool}-21 100
+          done
 
       - uses: actions/cache@v4
         with:
@@ -212,12 +230,18 @@ jobs:
 
       - name: Install dependencies
         run: |
+          . /etc/os-release
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          echo "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-21 main" | sudo tee /etc/apt/sources.list.d/llvm.list
           sudo apt-get update -qq
           sudo apt-get install -y \
-            build-essential ccache clang cmake gcovr \
+            build-essential ccache clang-21 cmake gcovr \
-            libc6-dbg llvm mold ninja-build python3 valgrind zstd
+            libc6-dbg llvm-21 lld-21 mold ninja-build python3 valgrind zstd
           sudo curl -Ls "https://dl.min.io/client/mc/release/linux-amd64/mc" \
             -o /usr/local/bin/mc && sudo chmod +x /usr/local/bin/mc
+          for tool in clang clang++ llvm-ar llvm-nm llvm-ranlib llvm-objcopy llvm-cov llvm-symbolizer lld ld.lld; do
+            sudo update-alternatives --install /usr/bin/${tool} ${tool} /usr/bin/${tool}-21 100
+          done
 
       - uses: actions/cache@v4
         with:
@@ -232,7 +256,8 @@ jobs:
           rm -rf build
           cmake -S . -B build -G Ninja -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
             -DCMAKE_C_FLAGS=--coverage -DCMAKE_CXX_FLAGS=--coverage \
-            -DCMAKE_BUILD_TYPE=Debug -DDISABLE_TSAN=ON
+            -DCMAKE_BUILD_TYPE=Debug -DDISABLE_TSAN=ON \
+            -DUSE_SIMD_FALLBACK=ON
           ninja -C build
           ccache -s
 

CMakeLists.txt

@@ -139,6 +139,7 @@ add_custom_command(
   COMMAND_EXPAND_LISTS)
 
 add_library(${PROJECT_NAME} SHARED ${CMAKE_BINARY_DIR}/${PROJECT_NAME}.o)
+add_dependencies(${PROJECT_NAME} ${PROJECT_NAME}-object)
 set_target_properties(
   ${PROJECT_NAME} PROPERTIES LIBRARY_OUTPUT_DIRECTORY
                              "${CMAKE_CURRENT_BINARY_DIR}/radix_tree")
@@ -155,6 +156,7 @@ if(HAS_VERSION_SCRIPT)
 endif()
 
 add_library(${PROJECT_NAME}-static STATIC ${CMAKE_BINARY_DIR}/${PROJECT_NAME}.o)
+add_dependencies(${PROJECT_NAME}-static ${PROJECT_NAME}-object)
 if(CMAKE_BUILD_TYPE STREQUAL Debug)
   set_target_properties(${PROJECT_NAME}-static PROPERTIES LINKER_LANGUAGE CXX)
 else()
@@ -389,12 +391,10 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
         COMMAND ${HARDENING_CHECK} --help
         OUTPUT_VARIABLE hardening_check_help
         ERROR_VARIABLE hardening_check_help
-        OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_STRIP_TRAILING_WHITESPACE
+        OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_STRIP_TRAILING_WHITESPACE)
-        RESULT_VARIABLE hardening_check_help_result)
       set(hardening_check_arch_flags "")
-      if(hardening_check_help_result EQUAL 0)
+      # Control flow integrity (CET) is x86-only and branch protection (PAC/BTI)
-        # Control flow integrity (CET) is x86-only and branch protection
+      # is arm64-only, so ignore whichever doesn't apply.
-        # (PAC/BTI) is arm64-only, so ignore whichever doesn't apply.
       if(CMAKE_SYSTEM_PROCESSOR STREQUAL aarch64 OR CMAKE_SYSTEM_PROCESSOR
                                                     STREQUAL arm64)
         if(hardening_check_help MATCHES "nocfprotection")
@@ -405,7 +405,6 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
           list(APPEND hardening_check_arch_flags --nobranchprotection)
         endif()
       endif()
-      endif()
       add_test(
         NAME hardening_check
         COMMAND ${HARDENING_CHECK} $<TARGET_FILE:${PROJECT_NAME}> --nofortify

ConflictSet.cpp

@@ -3080,7 +3080,7 @@ Node *firstGeqPhysical(Node *n, const TrivialSpan key) {
 #define PRESERVE_NONE
 #endif
 
-#if __has_attribute(musttail) && __has_attribute(preserve_none)
+#if __has_attribute(musttail)
 constexpr bool kEnableInterleaved = true;
 #else
 constexpr bool kEnableInterleaved = false;
@@ -5040,9 +5040,12 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
     assert(allPointWrites || sorted);
 #endif
 
-    if (kEnableInterleaved && count > 1) {
+    if constexpr (kEnableInterleaved) {
+      if (count > 1) {
         interleavedWrites(writes, count, InternalVersionT(writeVersion));
-    } else {
+        return;
+      }
+    }
     for (int i = 0; i < count; ++i) {
       const auto &w = writes[i];
       auto begin = TrivialSpan(w.begin.p, w.begin.len);
@@ -5056,7 +5059,6 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
       }
     }
   }
-  }
 
   void addWrites(const WriteRange *writes, int count, int64_t writeVersion) {
 #if !USE_64_BIT