Nix updates 2.3

.codespellignore

@@ -2,3 +2,4 @@ Crate
 crate
 InOut
 copyable
+sord

.github/workflows/nix.yml

@@ -0,0 +1,68 @@
+name: "NixOS Builds"
+on:
+  pull_request:
+  push:
+jobs:
+  dev:
+    strategy:
+      matrix:
+        include:
+          - name: nixos-20.09-gcc
+            os: nixos-20.09
+            use_clang: false
+            use_clazy: false
+            ccache: ccache-gcc
+    name: "nix-shell ${{ matrix.name }}"
+    runs-on: ubuntu-latest
+    steps:
+    - name: ccache cache files
+      uses: actions/cache@v2
+      with:
+        path: ~/.ccache
+        key: ${{ matrix.os }}-${{ matrix.ccache }}-${{ github.head_ref }}-${{ github.run_number }}
+        restore-keys: |
+          ${{ matrix.os }}-${{ matrix.ccache }}-${{ github.head_ref }}
+          ${{ matrix.os }}-${{ matrix.ccache }}-
+    - name: cache nix store
+      uses: actions/cache@v2
+      with:
+        path: /nix/store
+        key: ${{ matrix.os }}-nix-${{ github.head_ref }}-${{ github.run_number }}
+        restore-keys: |
+          ${{ matrix.os }}-nix-${{ github.head_ref }}
+          ${{ matrix.os }}-nix-
+    - uses: actions/checkout@v2.3.4
+    - uses: cachix/install-nix-action@v12
+      with:
+        nix_path: nixpkgs=channel:${{ matrix.os }}
+    - run: |
+        nix-shell --arg enableKeyfinder true --arg useClang ${{ matrix.use_clang }} \
+          --arg useClazy ${{ matrix.use_clazy }} --arg defaultLv2Plugins true \
+          --command "configure && build && run-tests"
+  pkg:
+    strategy:
+      matrix:
+        include:
+          - name: nixos-20.09
+            os: nixos-20.09
+    name: "nix-build"
+    runs-on: ubuntu-latest
+    steps:
+    - name: cache nix store
+      uses: actions/cache@v1.1.0
+      with:
+        path: /nix/store
+        key: ${{ matrix.os }}-nix-${{ github.head_ref }}-${{ github.run_number }}
+        restore-keys: |
+          ${{ matrix.os }}-nix-${{ github.head_ref }}
+          ${{ matrix.os }}-nix-
+    - uses: actions/checkout@v2.3.4
+    - uses: cachix/install-nix-action@v12
+      with:
+        nix_path: nixpkgs=channel:${{ matrix.os }}
+    - run: |
+        if [ -n "$CACHIX_SIGNING_KEY" ]; then
+          nix-build shell.nix --arg releaseMode true --arg defaultLv2Plugins true | cachix push mixxx;
+        else
+          nix-build shell.nix --arg releaseMode true --arg defaultLv2Plugins true
+        fi

.gitignore

@@ -63,6 +63,9 @@ compile_commands.json
 # Exclude buildenv directory from our helper scripts
 /buildenv/
 
+# Ignore nix-build result links
+/result*
+
 # CMake build configurations, generated by tools/windows_buildenv.bat
 CMakeSettings.json
 

CMakeLists.txt

@@ -57,6 +57,13 @@ endif()
 if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   # using regular Clang or AppleClang
   set(LLVM_CLANG true)
+  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS "10.0.0" AND
+     CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    message(WARNING "Found LLVM < 10 which has known optimization bugs with \
+    certain glibc versions. In case your build fails with linking errors. \
+    Use try using gcc if possible. Pass -DFAST_MATH=off to allow compilation
+    to a slow binary. See https://bugs.llvm.org/show_bug.cgi?id=45034")
+  endif()
 else()
   set(LLVM_CLANG false)
 endif()
@@ -95,9 +102,13 @@ endif()
 #
 # Optimizations
 #
-
 set(OPTIMIZE "portable" CACHE STRING "Optimization and Tuning (set to off, portable, native, legacy)")
 string(TOLOWER "${OPTIMIZE}" OPTIMIZE)
+
+# certain combinations of llvm and glibc cause problems with fastmath at link time. Add option to disable
+# fast-math but still allow other optimizations
+option(FAST_MATH "Use -fast-math optimization. Only disable this when linking fails with LLVM/GCC." ON)
+
 message(STATUS "Optimization level: ${OPTIMIZE}")
 
 # CMAKE_INTERPROCEDURAL_OPTIMIZATION can be defined to override the default behaviour.
@@ -244,9 +255,14 @@ elseif(GNU_GCC OR LLVM_CLANG)
     # faster, measured on a Atom CPU.
     add_compile_options(
       -O3
-      -ffast-math
       -funroll-loops
     )
+    if(FAST_MATH)
+      add_compile_options(
+        -ffast-math
+      )
+    endif()
+
     # set -fomit-frame-pointer when we don't profile and are not using
     # Clang sanitizers.
     # Note: It is only included in -O on machines where it does not