Catch CI up with github

.github/workflows/main.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         # Build each combination of OS and release/debug variants
-        os: [ "ubuntu-latest", "ubuntu-18.04", "macos-11", "macos-12", "freebsd-12.2", "freebsd-13.0" ]
+        os: [ "ubuntu-latest", "ubuntu-18.04", "ubuntu-20.04", "macos-11", "macos-12", "freebsd-12.2", "freebsd-13.0" ]
         build-type: [ Release, Debug ]
         # Extra cmake flags.  GitHub Actions matrix overloads `include` to mean
         # 'add extra things to a job' and 'add jobs'.  You can add extra things
@@ -32,7 +32,9 @@ jobs:
           - os: "ubuntu-18.04"
             dependencies: "sudo apt install ninja-build"
             cmake-flags: "-DSNMALLOC_USE_CXX17=ON"
-          - os: "ubuntu-latest"
+          - os: "ubuntu-20.04"
+            dependencies: "sudo apt install ninja-build"
+          - os: "ubuntu-latest" # 22.04 at time of writing
             dependencies: "sudo apt install ninja-build"
           - os: "macos-11"
             # The homebrew packages are broken at the moment and error out
@@ -62,19 +64,32 @@ jobs:
             dependencies: "sudo apt install ninja-build"
           # Extra build to check using pthread library for destructing local state.
           - os: "ubuntu-latest"
-            variant: "Ubuntu (with pthread destructors)."
+            variant: "with pthread destructors"
             dependencies: "sudo apt install ninja-build"
             build-type: Debug
             self-host: true
-            extra-cmake-flags: "-DSNMALLOC_USE_PTHREAD_DESTRUCTORS=On -DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_C_COMPILER=clang-10"
+            extra-cmake-flags: "-DSNMALLOC_USE_PTHREAD_DESTRUCTORS=On"
           # Add an extra element to the matrix that does a build with clang 12
           # but doesn't run tests.
           - os: "freebsd-13.0"
             variant: Clang 12 (Build only)
             extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++12"
             build-only: yes
+          # Check that we can build specifically with libstdc++
           - os: "ubuntu-latest"
-            variant: Clang 10 libstdc++ (Build only)
+            variant: "libstdc++ (Build only)"
+            dependencies: "sudo apt install ninja-build"
+            extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++ -DCMAKE_CXX_FLAGS=-stdlib=libstdc++"
+            build-only: yes
+          # Replay some of the above tests with clang-10 specifically
+          - os: "ubuntu-20.04"
+            variant: "clang-10 (with pthread destructors)."
+            dependencies: "sudo apt install ninja-build"
+            build-type: Debug
+            self-host: true
+            extra-cmake-flags: "-DSNMALLOC_USE_PTHREAD_DESTRUCTORS=On -DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_C_COMPILER=clang-10"
+          - os: "ubuntu-20.04"
+            variant: "clang-10 libstdc++ (Build only)"
             dependencies: "sudo apt install ninja-build"
             extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_C_COMPILER=clang-10 -DCMAKE_CXX_FLAGS=-stdlib=libstdc++"
             build-only: yes
@@ -114,12 +129,17 @@ jobs:
     strategy:
       matrix:
         # Build just release variant as Debug is too slow.
-        os: [ "ubuntu-latest"]
         build-type: [ Release ]
         include:
           - os: "ubuntu-latest"
             continue-on-error: # Don't class as an error if this fails, until we have a more reliablity.
-            variant: Clang 10 libc++ (TSan + UBSan)
+            variant: "libc++ (TSan + UBSan)"
+            dependencies: "sudo apt install ninja-build"
+            extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++ -DCMAKE_CXX_FLAGS=-stdlib=\"libc++ -g\" -DSNMALLOC_SANITIZER=undefined,thread"
+          # Also test specifically with clang-10 (on ubuntu-20.04)
+          - os: "ubuntu-20.04"
+            continue-on-error: # Don't class as an error if this fails, until we have a more reliablity.
+            variant: "clang-10 libc++ (TSan + UBSan)"
             dependencies: "sudo apt install ninja-build"
             extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_CXX_FLAGS=-stdlib=\"libc++ -g\" -DSNMALLOC_SANITIZER=undefined,thread"
       # Don't abort runners if a single one fails
@@ -150,26 +170,31 @@ jobs:
             triple: arm-linux-gnueabihf
             rtld: ld-linux-armhf.so.3
             ld-flavour: lld
+            host-os: ubuntu-latest
           - name: arm64
             system-processor: aarch64
             triple: aarch64-linux-gnu
             rtld: ld-linux-aarch64.so.1
             ld-flavour: lld
+            host-os: ubuntu-latest
           - name: ppc64el
             system-processor: powerpc64le
             triple: powerpc64le-linux-gnu
             rtld: ld64.so.2
             ld-flavour: lld
+            # See https://github.com/microsoft/snmalloc/issues/576
+            host-os: ubuntu-20.04
           - name: riscv64
             system-processor: riscv64
             triple: riscv64-linux-gnu
             rtld: ld-linux-riscv64-lp64d.so.1
             extra-packages: binutils-riscv64-linux-gnu
             ld-flavour: bfd
             ld: /usr/bin/riscv64-linux-gnu-ld.bfd
+            host-os: ubuntu-latest
       # Don't abort runners if a single one fails
       fail-fast: false
-    runs-on: ubuntu-latest
+    runs-on: ${{matrix.host-os}}
     name: ${{matrix.build-type}} cross-build for ${{ matrix.arch.triple }}
     steps:
     - uses: actions/checkout@v2

src/snmalloc/ds/aba.h

@@ -141,7 +141,7 @@ namespace snmalloc
   class ABA
   {
     std::atomic<T*> ptr = nullptr;
-    std::atomic_flag lock = ATOMIC_FLAG_INIT;
+    std::atomic<bool> lock{false};
 
   public:
     // This method is used in Verona
@@ -154,7 +154,7 @@ namespace snmalloc
 
     Cmp read()
     {
-      while (lock.test_and_set(std::memory_order_acquire))
+      while (lock.exchange(true, std::memory_order_acquire))
         Aal::pause();
 
 #  if !defined(NDEBUG) && !defined(SNMALLOC_DISABLE_ABA_VERIFY)
@@ -184,7 +184,7 @@ namespace snmalloc
 
       ~Cmp()
       {
-        parent->lock.clear(std::memory_order_release);
+        parent->lock.store(false, std::memory_order_release);
 #  if !defined(NDEBUG) && !defined(SNMALLOC_DISABLE_ABA_VERIFY)
         operation_in_flight = false;
 #  endif

src/snmalloc/mem/pooled.h

@@ -24,25 +24,25 @@ namespace snmalloc
     std::atomic<T*> next{nullptr};
     /// Used by the pool to keep the list of all entries ever created.
     capptr::Alloc<T> list_next;
-    std::atomic_flag in_use = ATOMIC_FLAG_INIT;
+    std::atomic<bool> in_use{false};
 
   public:
     void set_in_use()
     {
-      if (in_use.test_and_set())
+      if (in_use.exchange(true))
         error("Critical error: double use of Pooled Type!");
     }
 
     void reset_in_use()
     {
-      in_use.clear();
+      in_use.store(false);
     }
 
     bool debug_is_in_use()
     {
-      bool result = in_use.test_and_set();
+      bool result = in_use.exchange(true);
       if (!result)
-        in_use.clear();
+        in_use.store(false);
       return result;
     }
   };