ci: add MemorySanitizer CI job

Add build_msan_toolchain.sh to produce a tarball containing an
MSan-instrumented libc++/libc++abi/libunwind toolchain, and add an msan
CI job that downloads the tarball and runs the test suite under MSan.

Also add USE_MSAN CMake option that disables conflicting sanitizers,
switches to lld, and propagates -fsanitize=memory to the shared library
and fuzz_driver targets.

.gitea/workflows/ci.yml

@@ -19,15 +19,8 @@ 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-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
+          sudo apt-get install -y git nodejs pre-commit
 
       - uses: actions/cache@v4
         with:
@@ -61,28 +54,28 @@ jobs:
           path: /var/cache/apt/archives
           key: apt-amd64-${{ hashFiles('.gitea/workflows/ci.yml') }}
 
-      - name: Install dependencies
+      - name: Install common dependencies
+        run: |
+          sudo apt-get update -qq
+          sudo apt-get install -y \
+            build-essential ccache cmake gcc g++ libc6-dbg \
+            ninja-build python3 valgrind zstd
+          sudo curl -Ls "https://minio.weaselab.dev/public/$(uname -m)/mc.RELEASE.2025-08-13T08-35-41Z" \
+            -o /usr/local/bin/mc && sudo chmod +x /usr/local/bin/mc
+
+      - name: Install LLVM toolchain
+        if: matrix.name != 'gcc'
         run: |
           . /etc/os-release
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           echo "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-21 main" | sudo tee /etc/apt/sources.list.d/llvm.list
           sudo apt-get update -qq
           sudo apt-get install -y \
-            build-essential ccache clang-21 cmake gcc g++ \
-            libc6-dbg llvm-21 lld-21 mold ninja-build python3 valgrind zstd
-          sudo curl -Ls "https://dl.min.io/client/mc/release/linux-amd64/mc" \
-            -o /usr/local/bin/mc && sudo chmod +x /usr/local/bin/mc
+            clang-21 llvm-21 lld-21 mold
           for tool in clang clang++ llvm-ar llvm-nm llvm-ranlib llvm-objcopy llvm-cov llvm-symbolizer lld ld.lld; do
             sudo update-alternatives --install /usr/bin/${tool} ${tool} /usr/bin/${tool}-21 100
           done
 
-      - uses: actions/cache@v4
-        with:
-          path: .ccache
-          key: ccache-${{ matrix.name }}-${{ gitea.sha }}
-          restore-keys: |
-            ccache-${{ matrix.name }}-
-
       - name: Build
         run: |
           export CCACHE_DIR="$GITHUB_WORKSPACE/.ccache"
@@ -141,16 +134,23 @@ jobs:
           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-21 cmake devscripts \
-            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-$(dpkg --print-architecture)/mc" \
+            build-essential ccache clang-21 cmake devscripts \
+            libc6-dbg llvm-21 lld-21 mold ninja-build rpm \
+            valgrind zstd
+          sudo curl -Ls "https://minio.weaselab.dev/public/$(uname -m)/mc.RELEASE.2025-08-13T08-35-41Z" \
             -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
 
+      - name: Install paper build dependencies
+        if: matrix.arch == 'amd64'
+        run: |
+          sudo apt-get install -y \
+            biber latexmk \
+            texlive-bibtex-extra texlive-fonts-recommended \
+            texlive-latex-extra texlive-pictures
+
       - uses: actions/cache@v4
         with:
           path: .ccache
@@ -218,6 +218,87 @@ jobs:
             --link "https://minio.weaselab.dev/jenkins/conflict-set/${{ gitea.run_number }}/release-${{ matrix.arch }}/Test.xml.zst" \
             | tee -a "$GITHUB_STEP_SUMMARY"
 
+  msan:
+    runs-on: ubuntu-latest-amd64
+    env:
+      MSAN_VERSION: "21.1.8"
+      MSAN_URL: "https://minio.weaselab.dev/public/x86_64/msan-toolchain-21.1.8.tar.zst"
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/cache@v4
+        with:
+          path: /var/cache/apt/archives
+          key: apt-amd64-${{ hashFiles('.gitea/workflows/ci.yml') }}
+
+      - name: Install dependencies
+        run: |
+          . /etc/os-release
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          echo "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-21 main" | sudo tee /etc/apt/sources.list.d/llvm.list
+          sudo apt-get update -qq
+          sudo apt-get install -y \
+            build-essential ccache clang-21 cmake libc6-dbg \
+            llvm-21 lld-21 mold ninja-build python3 zstd
+          for tool in clang clang++ llvm-ar llvm-nm llvm-ranlib llvm-objcopy llvm-cov llvm-symbolizer lld ld.lld; do
+            sudo update-alternatives --install /usr/bin/${tool} ${tool} /usr/bin/${tool}-21 100
+          done
+
+      - name: Download MSan toolchain
+        run: |
+          curl -Ls "${MSAN_URL}" -o /tmp/msan-toolchain.tar.zst
+          sudo mkdir -p /opt/msan
+          sudo tar --zstd -xf /tmp/msan-toolchain.tar.zst -C /opt/msan
+
+      - uses: actions/cache@v4
+        with:
+          path: .ccache
+          key: ccache-msan-${{ gitea.sha }}
+          restore-keys: |
+            ccache-msan-
+
+      - name: Build
+        run: |
+          export CCACHE_DIR="$GITHUB_WORKSPACE/.ccache"
+          rm -rf build
+          cmake -S . -B build -G Ninja \
+            -DCMAKE_C_COMPILER=clang \
+            -DCMAKE_CXX_COMPILER=clang++ \
+            -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
+            -DCMAKE_BUILD_TYPE=Debug \
+            -DDISABLE_TSAN=ON \
+            -DUSE_MSAN=ON \
+            -DCMAKE_CXX_FLAGS="-fsanitize=memory -stdlib=libc++ -I/opt/msan/include/c++/v1 -L/opt/msan/lib -UNDEBUG" \
+            -DCMAKE_EXE_LINKER_FLAGS="-stdlib=libc++ -Wl,-rpath,/opt/msan/lib" \
+            -DCMAKE_SHARED_LINKER_FLAGS="-stdlib=libc++ -Wl,-rpath,/opt/msan/lib"
+          ninja -C build
+          ccache -s
+
+      - name: Test
+        run: |
+          cd build
+          ctest --no-compress-output --test-output-size-passed 100000 --test-output-size-failed 100000 -T Test -j "$(nproc)" --timeout 300 > /dev/null
+
+      - name: Upload test results to MinIO
+        if: always()
+        env:
+          MINIO_ACCESS_KEY: ${{ secrets.MINIO_ACCESS_KEY }}
+          MC_HOST_minio: https://${{ secrets.MINIO_ACCESS_KEY }}:${{ secrets.MINIO_SECRET_KEY }}@minio.weaselab.dev
+        run: |
+          if [ -z "$MINIO_ACCESS_KEY" ]; then
+            echo "MinIO credentials not configured; skipping upload"
+            exit 0
+          fi
+          zstd build/Testing/*/Test.xml
+          mc cp build/Testing/*/Test.xml.zst "minio/jenkins/conflict-set/${{ gitea.run_number }}/msan/"
+
+      - name: Test summary
+        if: always()
+        run: |
+          python3 ctest_summary.py build/Testing/*/Test.xml \
+            --link "https://minio.weaselab.dev/jenkins/conflict-set/${{ gitea.run_number }}/msan/Test.xml.zst" \
+            | tee -a "$GITHUB_STEP_SUMMARY"
+
   coverage:
     runs-on: ubuntu-latest-amd64
     steps:
@@ -237,7 +318,7 @@ jobs:
           sudo apt-get install -y \
             build-essential ccache clang-21 cmake gcovr \
             libc6-dbg llvm-21 lld-21 mold ninja-build python3 valgrind zstd
-          sudo curl -Ls "https://dl.min.io/client/mc/release/linux-amd64/mc" \
+          sudo curl -Ls "https://minio.weaselab.dev/public/$(uname -m)/mc.RELEASE.2025-08-13T08-35-41Z" \
             -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

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.18)
 project(
   conflict-set
-  VERSION 0.0.14
+  VERSION 0.1.0
   DESCRIPTION
     "A data structure for optimistic concurrency control on ranges of bitwise-lexicographically-ordered keys."
   HOMEPAGE_URL "https://git.weaselab.dev/weaselab/conflict-set"
@@ -49,6 +49,18 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
         ${LLVM_OBJCOPY}
         CACHE FILEPATH "path to objcopy binary" FORCE)
   endif()
+  if(USE_MSAN)
+    find_program(LLD_LINKER lld)
+    if(LLD_LINKER)
+      set(CMAKE_LINKER_TYPE
+          "LLD"
+          CACHE STRING "Use LLD linker" FORCE)
+      set(CMAKE_LINKER
+          ${LLD_LINKER}
+          CACHE FILEPATH "path to linker binary" FORCE)
+      add_link_options("-fuse-ld=lld")
+    endif()
+  endif()
 endif()
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
@@ -103,6 +115,8 @@ option(USE_SIMD_FALLBACK
 
 option(DISABLE_TSAN "Disable TSAN" OFF)
 
+option(USE_MSAN "Build with MemorySanitizer (disables ASan/UBSan)" OFF)
+
 # This is encouraged according to
 # https://valgrind.org/docs/manual/manual-core-adv.html#manual-core-adv.clientreq
 include_directories(SYSTEM ${CMAKE_CURRENT_SOURCE_DIR}/third_party/valgrind)
@@ -232,8 +246,10 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
   target_compile_definitions(conflict_set_main PRIVATE ENABLE_MAIN)
   target_link_libraries(conflict_set_main PRIVATE nanobench)
 
-  if(NOT APPLE)
-    # libfuzzer target, to generate/manage corpus
+  if(NOT APPLE AND NOT USE_MSAN)
+    # libfuzzer target, to generate/manage corpus. MSan requires an instrumented
+    # libfuzzer runtime, which is not shipped with the compiler, so skip this
+    # target when building with MSan.
     set(FUZZ_FLAGS "-fsanitize=fuzzer-no-link,address,undefined")
     include(CheckCXXCompilerFlag)
     cmake_push_check_state()
@@ -257,8 +273,13 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
   add_executable(fuzz_driver ConflictSet.cpp FuzzTestDriver.cpp)
   target_compile_options(fuzz_driver PRIVATE ${TEST_FLAGS})
   if(NOT CMAKE_CROSSCOMPILING)
-    target_compile_options(fuzz_driver PRIVATE -fsanitize=address,undefined)
-    target_link_options(fuzz_driver PRIVATE -fsanitize=address,undefined)
+    if(USE_MSAN)
+      target_compile_options(fuzz_driver PRIVATE -fsanitize=memory)
+      target_link_options(fuzz_driver PRIVATE -fsanitize=memory)
+    else()
+      target_compile_options(fuzz_driver PRIVATE -fsanitize=address,undefined)
+      target_link_options(fuzz_driver PRIVATE -fsanitize=address,undefined)
+    endif()
   endif()
   target_compile_definitions(fuzz_driver PRIVATE ENABLE_FUZZ)
   target_include_directories(fuzz_driver
@@ -269,7 +290,9 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
   endforeach()
 
   # tsan tests
-  if(NOT CMAKE_CROSSCOMPILING AND NOT DISABLE_TSAN)
+  if(NOT CMAKE_CROSSCOMPILING
+     AND NOT DISABLE_TSAN
+     AND NOT USE_MSAN)
     add_executable(tsan_driver ConflictSet.cpp FuzzTestDriver.cpp)
     target_compile_options(tsan_driver PRIVATE ${TEST_FLAGS} -fsanitize=thread)
     target_link_options(tsan_driver PRIVATE -fsanitize=thread)
@@ -491,6 +514,11 @@ target_include_directories(
   PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
          $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME}>)
 
+if(USE_MSAN)
+  target_compile_options(${PROJECT_NAME} PUBLIC -fsanitize=memory)
+  target_link_options(${PROJECT_NAME} PUBLIC -fsanitize=memory)
+endif()
+
 set_target_properties(
   ${PROJECT_NAME} PROPERTIES VERSION ${PROJECT_VERSION}
                              SOVERSION ${PROJECT_VERSION_MAJOR})

Dockerfile

@@ -1,46 +0,0 @@
-FROM ubuntu:rolling
-
-WORKDIR /tmp
-ENV HOME=/tmp
-RUN chmod -R 777 /tmp
-
-# Install apt dependencies
-RUN apt-get update
-RUN apt-get upgrade -y
-RUN TZ=America/Los_Angeles DEBIAN_FRONTEND=noninteractive apt-get install -y \
-    biber \
-    build-essential \
-    ccache \
-    clang \
-    cmake \
-    curl \
-    devscripts \
-    gcovr \
-    git \
-    latexmk \
-    libc6-dbg \
-    llvm \
-    mold \
-    ninja-build \
-    nodejs \
-    pre-commit \
-    python3-requests \
-    rpm \
-    texlive-bibtex-extra \
-    texlive-fonts-recommended \
-    texlive-latex-extra \
-    texlive-pictures \
-    valgrind \
-    wget \
-    zstd
-
-# MinIO client, for uploading build artifacts
-RUN curl -Ls "https://dl.min.io/client/mc/release/linux-$(dpkg --print-architecture)/mc" \
-    -o /usr/local/bin/mc && chmod +x /usr/local/bin/mc
-
-ENV CC=clang
-ENV CXX=clang++
-
-# Try to have all the pre-commit hooks we'll need already initialized
-COPY .pre-commit-config.yaml /tmp/
-RUN git init && pre-commit install-hooks

build_msan_toolchain.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+
+set -euxo pipefail
+
+LLVM_VERSION="${LLVM_VERSION:-21}"
+MSAN_PREFIX="${MSAN_PREFIX:-$PWD/msan}"
+JOBS="${JOBS:-$(nproc)}"
+
+cd /tmp
+rm -rf libcxx-msan
+mkdir libcxx-msan
+cd libcxx-msan
+
+git clone --depth=1 "https://github.com/llvm/llvm-project.git" -b "release/${LLVM_VERSION}.x"
+
+cmake -S llvm-project/runtimes -B build \
+  -DCMAKE_BUILD_TYPE=Release \
+  -DCMAKE_C_COMPILER="clang-${LLVM_VERSION}" \
+  -DCMAKE_CXX_COMPILER="clang++-${LLVM_VERSION}" \
+  -DLLVM_USE_SANITIZER=MemoryWithOrigins \
+  -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" \
+  -DLLVM_TARGETS_TO_BUILD=Native \
+  -DCMAKE_INSTALL_PREFIX="${MSAN_PREFIX}" \
+  -DLIBCXXABI_USE_LLVM_UNWINDER=ON \
+  -DLIBCXXABI_ENABLE_STATIC_UNWINDER=ON \
+  -DLIBCXX_USE_COMPILER_RT=ON \
+  -DLIBCXXABI_USE_COMPILER_RT=ON \
+  -DLIBUNWIND_USE_COMPILER_RT=ON \
+  -DLIBCXX_INCLUDE_TESTS=OFF \
+  -DLIBCXXABI_INCLUDE_TESTS=OFF \
+  -DLIBUNWIND_INCLUDE_TESTS=OFF \
+  -DLIBCXX_ENABLE_CLANG_TIDY=OFF
+
+cmake --build build -j"${JOBS}"
+cmake --install build
+
+VERSION="$(clang-"${LLVM_VERSION}" --version | head -n1 | sed -E 's/.*clang version ([0-9.]+).*/\1/')"
+TARBALL="msan-toolchain-${VERSION}.tar.zst"
+
+tar --zstd -cf "${TARBALL}" -C "${MSAN_PREFIX}" .
+
+TARBALL_PATH="$(pwd)/${TARBALL}"
+echo "Created: ${TARBALL_PATH}"