Run clang-tidy on macOS runners instead of Linux (halide#7746)

* Run clang-tidy on macOS runners instead of LInux

The current macOS runners have twice the RAM and more CPU power.

Also, drive-by change to allow specifying the parallelism that the run-clang-tidy script should use (defaults to nproc)

* Update Generator.cpp

* Update run-clang-tidy.sh

* Update run-clang-tidy.sh

.github/workflows/presubmit.yml

@@ -23,24 +23,24 @@ jobs:
           source: '.'
           extensions: 'h,c,cpp'
           clangFormatVersion: 16
+  # As of Aug 2023, the macOS runners have more RAM (14GB vs 7GB) and CPU (3 cores vs 2)
+  # than the Linux and Windows runners, so let's use those instead, since clang-tidy is
+  # a bit of a sluggard
   check_clang_tidy:
     name: Check clang-tidy
-    runs-on: ubuntu-20.04
+    runs-on: macos-13
     steps:
       - uses: actions/checkout@v3
       - name: Install clang-tidy
         run: |
-          # from apt.llvm.org
-          # wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -
-          sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 15CF4D18AF4F7421
-          sudo apt-add-repository "deb https://apt.llvm.org/$(lsb_release -sc)/ llvm-toolchain-$(lsb_release -sc)-16 main"
-          sudo apt-get update
-          sudo apt-get install llvm-16 clang-16 liblld-16-dev libclang-16-dev clang-tidy-16 ninja-build
+          brew update
+          brew install llvm@16 ninja coreutils
       - name: Run clang-tidy
         run: |
-          export CC=clang-16
-          export CXX=clang++-16
-          export CLANG_TIDY_LLVM_INSTALL_DIR=/usr/lib/llvm-16
+          export CC=/usr/local/opt/llvm/bin/clang
+          export CXX=/usr/local/opt/llvm/bin/clang++
+          export CLANG_TIDY_LLVM_INSTALL_DIR=/usr/local/opt/llvm
+          export CMAKE_GENERATOR=Ninja
           ./run-clang-tidy.sh
   check_cmake_file_lists:
     name: Check CMake file lists

run-clang-tidy.sh

@@ -4,9 +4,31 @@ set -e
 
 ROOT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
 
-[[ "$1" != "" && "$1" != "-fix" ]] && echo "The only supported argument is -fix" && exit
-
-FIX=$1
+usage() { echo "Usage: $0 [-j MAX_PROCESS_COUNT] [-f]" 1>&2; exit 1; }
+
+J=$(nproc)
+FIX=
+
+while getopts ":j:f" o; do
+    case "${o}" in
+        j)
+            J="${OPTARG}"
+            [[ "${J}" =~ ^[0-9]+$ ]] || ( echo "-j requires an integer argument"; usage )
+            ;;
+        f)
+            FIX="-fix"
+            ;;
+        *)
+            usage
+            ;;
+    esac
+done
+shift $((OPTIND-1))
+
+echo "Using ${J} processes."
+if [ -n "${FIX}" ]; then
+    echo "Operating in -fix mode!"
+fi
 
 # We are currently standardized on using LLVM/Clang16 for this script.
 # Note that this is totally independent of the version of LLVM that you
@@ -47,7 +69,8 @@ cmake -DCMAKE_BUILD_TYPE=Debug \
 [ -a ${CLANG_TIDY_BUILD_DIR}/compile_commands.json ]
 
 # We must populate the includes directory to check things outside of src/
-cmake --build ${CLANG_TIDY_BUILD_DIR} --target HalideIncludes
+echo Building HalideIncludes...
+cmake --build ${CLANG_TIDY_BUILD_DIR} -j $(nproc) --target HalideIncludes
 
 RUN_CLANG_TIDY=${CLANG_TIDY_LLVM_INSTALL_DIR}/bin/run-clang-tidy
 
@@ -57,6 +80,7 @@ RUN_CLANG_TIDY=${CLANG_TIDY_LLVM_INSTALL_DIR}/bin/run-clang-tidy
 # Skip DefaultCostModel.cpp as it relies on cost_model.h.
 # Skip GenGen.cpp and RunGenMain.cpp as they bring clang-tidy to its knees,
 # for reasons that aren't entirely clear yet.
+echo Finding targets...
 CLANG_TIDY_TARGETS=$(find \
      "${ROOT_DIR}/src" \
      "${ROOT_DIR}/python_bindings" \
@@ -71,9 +95,10 @@ CLANG_TIDY_TARGETS=$(find \
 # so we will instead build an include filter
 CLANG_TIDY_HEADER_FILTER=".*/src/.*|.*/python_bindings/.*|.*/tools/.*|.*/util/.*"
 
+echo Running clang-tidy...
 ${RUN_CLANG_TIDY} \
     ${FIX} \
-    -j $(nproc) \
+    -j ${J} \
     -header-filter="${CLANG_TIDY_HEADER_FILTER}" \
     -quiet \
     -p ${CLANG_TIDY_BUILD_DIR} \

src/Generator.cpp

@@ -637,7 +637,7 @@ int generate_filter_main_inner(int argc,
                                char **argv,
                                const GeneratorFactoryProvider &generator_factory_provider) {
     static const char kUsage[] = R"INLINE_CODE(
-gengen
+gengenz
   [-g GENERATOR_NAME] [-f FUNCTION_NAME] [-o OUTPUT_DIR] [-r RUNTIME_NAME]
   [-d 1|0] [-e EMIT_OPTIONS] [-n FILE_BASE_NAME] [-p PLUGIN_NAME]
   [-s AUTOSCHEDULER_NAME] [-t TIMEOUT]