cmake_minimum_required(VERSION 3.18 FATAL_ERROR)
#cmake_policy(SET CMP0022 NEW)
#cmake_policy(SET CMP0023 NEW)

# Use compiler ID "AppleClang" instead of "Clang" for XCode.
# Not setting this sometimes makes XCode C compiler gets detected as "Clang",
# even when the C++ one is detected as "AppleClang".
cmake_policy(SET CMP0010 NEW)
cmake_policy(SET CMP0025 NEW)

# Enables CMake to set LTO on compilers other than Intel.
cmake_policy(SET CMP0069 NEW)
# Enable the policy for CMake subprojects.
# protobuf currently causes issues
#set(CMAKE_POLICY_DEFAULT_CMP0069 NEW)

# Suppress warning flags in default MSVC configuration.  It's not
# mandatory that we do this (and we don't if cmake is old), but it's
# nice when it's possible, and it's possible on our Windows configs.
cmake_policy(SET CMP0092 NEW)

# ---[ Project and semantic versioning.
project(Torch CXX C)

if(${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
  set(LINUX TRUE)
else()
  set(LINUX FALSE)
endif()

set(CMAKE_INSTALL_MESSAGE NEVER)

# check and set CMAKE_CXX_STANDARD
string(FIND "${CMAKE_CXX_FLAGS}" "-std=c++" env_cxx_standard)
if(env_cxx_standard GREATER -1)
  message(
      WARNING "C++ standard version definition detected in environment variable."
      "PyTorch requires -std=c++17. Please remove -std=c++ settings in your environment.")
endif()
set(CMAKE_CXX_STANDARD 17 CACHE STRING "The C++ standard whose features are requested to build this target.")
set(CMAKE_C_STANDARD   11 CACHE STRING "The C standard whose features are requested to build this target.")

# ---[ Utils
include(cmake/public/utils.cmake)

if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
  include(cmake/CheckAbi.cmake)
  string(APPEND CMAKE_CXX_FLAGS " -D_GLIBCXX_USE_CXX11_ABI=${GLIBCXX_USE_CXX11_ABI}")
  string(APPEND CMAKE_CUDA_FLAGS " -D_GLIBCXX_USE_CXX11_ABI=${GLIBCXX_USE_CXX11_ABI}")
  if(${GLIBCXX_USE_CXX11_ABI} EQUAL 1)
    set(CXX_STANDARD_REQUIRED ON)
  else()
    # Please note this is required in order to ensure compatibility between gcc 9 and gcc 7
    # This could be removed when all Linux PyTorch binary builds are compiled by the same toolchain again
    include(CheckCXXCompilerFlag)
    append_cxx_flag_if_supported("-fabi-version=11" CMAKE_CXX_FLAGS)
  endif()
endif()

set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

# One variable that determines whether the current cmake process is being run
# with the main Caffe2 library. This is useful for building modules - if
# modules are built with the main Caffe2 library then one does not need to do
# find caffe2 in the cmake script. One can usually guard it in some way like
#    if(NOT CAFFE2_CMAKE_BUILDING_WITH_MAIN_REPO)
#      find_package(Caffe2 REQUIRED)
#    endif()
set(CAFFE2_CMAKE_BUILDING_WITH_MAIN_REPO ON)

# Googletest's cmake files are going to set it on once they are processed. Let's
# set it at the very beginning so that the entire build is deterministic.
set(THREADS_PREFER_PTHREAD_FLAG ON)

if(NOT DEFINED BLAS_SET_BY_USER)
  if(DEFINED BLAS)
    set(BLAS_SET_BY_USER TRUE)
  else()
    message(STATUS "Not forcing any particular BLAS to be found")
    set(BLAS_SET_BY_USER FALSE)
  endif()
  set(BLAS_SET_BY_USER ${BLAS_SET_BY_USER} CACHE STRING "Marks whether BLAS was manually set by user or auto-detected")
endif()

# Apple specific
if(APPLE)
  # These lines are an attempt to make find_package(cuda) pick up
  # libcuda.dylib, and not cuda.framework.  It doesn't work all
  # the time, but it seems to help for some users.
  # TODO: replace this with a more robust fix
  set(CMAKE_FIND_FRAMEWORK LAST)
  set(CMAKE_FIND_APPBUNDLE LAST)

  # Get clang version on macOS
  execute_process( COMMAND ${CMAKE_CXX_COMPILER} --version OUTPUT_VARIABLE clang_full_version_string )
  string(REGEX REPLACE "Apple (.*) version ([0-9]+\\.[0-9]+).*" "\\2" CLANG_VERSION_STRING ${clang_full_version_string})
  message( STATUS "CLANG_VERSION_STRING:         " ${CLANG_VERSION_STRING} )


  # RPATH stuff
  set(CMAKE_MACOSX_RPATH ON)
  if(NOT IOS)
    # Determine if we can link against MPSGraph
    set(MPS_FOUND OFF)
    execute_process(
      COMMAND bash -c "xcrun --sdk macosx --show-sdk-version"
      RESULT_VARIABLE _exit_code
      OUTPUT_VARIABLE _macosx_sdk_version
      OUTPUT_STRIP_TRAILING_WHITESPACE)
    if(_exit_code EQUAL 0)
        set(_MPS_supported_os_version OFF)
        if(_macosx_sdk_version VERSION_GREATER_EQUAL 12.3)
            set(_MPS_supported_os_version ON)
        endif()
        message(STATUS "sdk version: ${_macosx_sdk_version}, mps supported: ${_MPS_supported_os_version}")
        execute_process(
          COMMAND bash -c "xcrun --sdk macosx --show-sdk-path"
          OUTPUT_VARIABLE _macosx_sdk_path
          OUTPUT_STRIP_TRAILING_WHITESPACE)
        set(_SDK_SEARCH_PATH "${_macosx_sdk_path}/System/Library/Frameworks/")
        set(_FRAMEWORK_SEARCH_PATH "/System/Library/Frameworks/")

        find_library(_MPS_fwrk_path_ NAMES MetalPerformanceShadersGraph MetalPerformanceShaders PATHS ${_FRAMEWORK_SEARCH_PATH} NO_DEFAULT_PATH)
        find_library(_MPS_sdk_path_ NAMES MetalPerformanceShadersGraph MetalPerformanceShaders PATHS ${_SDK_SEARCH_PATH} NO_DEFAULT_PATH)

        if(_MPS_supported_os_version AND _MPS_fwrk_path_ AND _MPS_sdk_path_)
          set(MPS_FOUND ON)
          message(STATUS "MPSGraph framework found")
        else()
          message(STATUS "MPSGraph framework not found")
        endif()
    else()
      message(STATUS "MPS: unable to get MacOS sdk version")
      message(STATUS "MPSGraph framework not found")
    endif()
  endif()
endif()

set(CPU_AARCH64 OFF)
set(CPU_INTEL OFF)

if(CMAKE_SYSTEM_PROCESSOR MATCHES "(AMD64|x86_64)")
  set(CPU_INTEL ON)
elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(aarch64|arm64)")
  set(CPU_AARCH64 ON)
endif()


# For non-supported platforms, turn USE_DISTRIBUTED off by default.
# It is not tested and likely won't work without additional changes.
if(NOT LINUX AND NOT WIN32)
  set(USE_DISTRIBUTED OFF CACHE STRING "Use distributed")
  # On macOS, if USE_DISTRIBUTED is enabled (specified by the user),
  # then make Gloo build with the libuv transport.
  if(APPLE AND USE_DISTRIBUTED)
    set(USE_LIBUV ON CACHE STRING "")
  endif()
endif()

# ---[ Options.
# Note to developers: if you add an option below, make sure you also add it to
# cmake/Summary.cmake so that the summary prints out the option values.
include(CMakeDependentOption)
option(ATEN_NO_TEST "Do not build ATen test binaries" OFF)
option(BUILD_BINARY "Build C++ binaries" OFF)
option(BUILD_DOCS "Build Caffe2 documentation" OFF)
option(BUILD_CUSTOM_PROTOBUF "Build and use Caffe2's own protobuf under third_party" ON)
option(BUILD_PYTHON "Build Python binaries" ON)
option(BUILD_CAFFE2 "Master flag to build Caffe2" OFF)
option(BUILD_LITE_INTERPRETER "Master flag to build Lite Interpreter" OFF)
cmake_dependent_option(
    BUILD_CAFFE2_OPS "Build Caffe2 operators" ON
    "BUILD_CAFFE2" OFF)
option(BUILD_SHARED_LIBS "Build libcaffe2.so" ON)
cmake_dependent_option(
    CAFFE2_LINK_LOCAL_PROTOBUF "If set, build protobuf inside libcaffe2.so." ON
    "BUILD_SHARED_LIBS AND BUILD_CUSTOM_PROTOBUF" OFF)
cmake_dependent_option(
    CAFFE2_USE_MSVC_STATIC_RUNTIME "Using MSVC static runtime libraries" ON
    "NOT BUILD_SHARED_LIBS" OFF)
option(BUILD_TEST "Build C++ test binaries (need gtest and gbenchmark)" OFF)
option(BUILD_AOT_INDUCTOR_TEST "Build C++ test binaries for aot-inductor" OFF)
option(BUILD_STATIC_RUNTIME_BENCHMARK "Build C++ binaries for static runtime benchmarks (need gbenchmark)" OFF)
option(BUILD_TENSOREXPR_BENCHMARK "Build C++ binaries for tensorexpr benchmarks (need gbenchmark)" OFF)
option(BUILD_MOBILE_BENCHMARK "Build C++ test binaries for mobile (ARM) targets(need gtest and gbenchmark)" OFF)
option(BUILD_MOBILE_TEST "Build C++ test binaries for mobile (ARM) targets(need gtest and gbenchmark)" OFF)
option(BUILD_JNI "Build JNI bindings" OFF)
option(BUILD_MOBILE_AUTOGRAD "Build autograd function in mobile build (in development)" OFF)
cmake_dependent_option(
    INSTALL_TEST "Install test binaries if BUILD_TEST is on" ON
    "BUILD_TEST" OFF)
option(USE_CPP_CODE_COVERAGE "Compile C/C++ with code coverage flags" OFF)
option(USE_COLORIZE_OUTPUT "Colorize output during compilation" ON)
option(USE_ASAN "Use Address+Undefined Sanitizers" OFF)
option(USE_TSAN "Use Thread Sanitizer" OFF)
option(USE_CUDA "Use CUDA" ON)
cmake_dependent_option(
     BUILD_LAZY_CUDA_LINALG "Build cuda linalg ops as separate library" ON "USE_CUDA AND LINUX AND BUILD_PYTHON" OFF)
cmake_dependent_option(
    BUILD_NVFUSER "Build NVFUSER" ON
    "USE_CUDA OR USE_ROCM" OFF)
cmake_dependent_option(USE_ROCM "Use ROCm" ON "LINUX" OFF)
option(CAFFE2_STATIC_LINK_CUDA "Statically link CUDA libraries" OFF)
cmake_dependent_option(
    USE_CUDNN "Use cuDNN" ON
    "USE_CUDA" OFF)
cmake_dependent_option(
    USE_STATIC_CUDNN "Use cuDNN static libraries" OFF
    "USE_CUDNN" OFF)
cmake_dependent_option(
    USE_CUSPARSELT "Use cuSPARSELt" ON
    "USE_CUDA" OFF)
cmake_dependent_option(
    BUILD_NVFUSER_BENCHMARK "Build C++ binaries for nvfuser benchmarks" OFF
    "USE_CUDA" OFF)
cmake_dependent_option(
    USE_EXPERIMENTAL_CUDNN_V8_API "Use experimental cuDNN v8 API" ON
    "USE_CUDNN" OFF)
option(USE_FBGEMM "Use FBGEMM (quantized 8-bit server operators)" ON)
option(USE_KINETO "Use Kineto profiling library" ON)
option(USE_CUPTI_SO "Use CUPTI as a shared library" ON)
option(USE_FAKELOWP "Use FakeLowp operators" OFF)
option(USE_FFMPEG "Use ffmpeg" OFF)
option(USE_GFLAGS "Use GFLAGS" OFF)
option(USE_GLOG "Use GLOG" OFF)
option(USE_LEVELDB "Use LEVELDB" OFF)
option(USE_LITE_PROTO "Use lite protobuf instead of full." OFF)
option(USE_LMDB "Use LMDB" OFF)
option(USE_MAGMA "Use MAGMA" ON)
option(USE_METAL "Use Metal for Caffe2 iOS build" ON)
option(USE_PYTORCH_METAL "Use Metal for PyTorch iOS build" OFF)
option(USE_PYTORCH_METAL_EXPORT "Export Metal models on MacOSX desktop" OFF)
option(USE_NATIVE_ARCH "Use -march=native" OFF)
cmake_dependent_option(
    USE_MPS "Use MPS for macOS build" ON
    "MPS_FOUND" OFF)
cmake_dependent_option(
    USE_NCCL "Use NCCL" ON
    "USE_CUDA OR USE_ROCM;UNIX;NOT APPLE" OFF)
cmake_dependent_option(USE_RCCL "Use RCCL" ON
    USE_NCCL OFF)
cmake_dependent_option(
    USE_STATIC_NCCL "Use static NCCL" OFF
    "USE_NCCL" OFF)
cmake_dependent_option(
    USE_SYSTEM_NCCL "Use system-wide NCCL" OFF
    "USE_NCCL" OFF)
option(USE_NNAPI "Use NNAPI" OFF)
option(USE_NNPACK "Use NNPACK" ON)
cmake_dependent_option(
    USE_NUMA "Use NUMA. Only available on Linux." ON
    "LINUX" OFF)
cmake_dependent_option(
    USE_NVRTC "Use NVRTC. Only available if USE_CUDA is on." OFF
    "USE_CUDA" OFF)
option(USE_NUMPY "Use NumPy" ON)
option(USE_OBSERVERS "Use observers module." OFF)
option(USE_OPENCL "Use OpenCL" OFF)
option(USE_OPENCV "Use OpenCV" OFF)
option(USE_OPENMP "Use OpenMP for parallel code" ON)
option(USE_PRECOMPILED_HEADERS "Use pre-compiled headers to accelerate build." OFF)

option(USE_PROF "Use profiling" OFF)
option(USE_QNNPACK "Use QNNPACK (quantized 8-bit operators)" ON)
option(USE_PYTORCH_QNNPACK "Use ATen/QNNPACK (quantized 8-bit operators)" ON)
option(USE_REDIS "Use Redis" OFF)
option(USE_ROCKSDB "Use RocksDB" OFF)
option(USE_SNPE "Use Qualcomm's SNPE library" OFF)
option(USE_SYSTEM_EIGEN_INSTALL
    "Use system Eigen instead of the one under third_party" OFF)
option(USE_TENSORRT "Using Nvidia TensorRT library" OFF)
cmake_dependent_option(
    USE_VALGRIND "Use Valgrind. Only available on Linux." ON
    "LINUX" OFF)

if(NOT DEFINED USE_VULKAN)
  cmake_dependent_option(
      USE_VULKAN "Use Vulkan GPU backend" ON
      "ANDROID" OFF)
endif()

option(USE_SLEEF_FOR_ARM_VEC256 "Use sleef for arm" OFF)
option(USE_SOURCE_DEBUG_ON_MOBILE "Enable " ON)
option(USE_LITE_INTERPRETER_PROFILER "Enable " ON)
option(USE_VULKAN_FP16_INFERENCE "Vulkan - Use fp16 inference" OFF)
option(USE_VULKAN_RELAXED_PRECISION "Vulkan - Use relaxed precision math in the kernels (mediump)" OFF)
# option USE_XNNPACK: try to enable xnnpack by default.
option(USE_XNNPACK "Use XNNPACK" ON)
option(USE_ZMQ "Use ZMQ" OFF)
option(USE_ZSTD "Use ZSTD" OFF)
option(TORCH_DISABLE_GPU_ASSERTS "Disable GPU asserts by default" OFF)
# Ensure that an ITT build is the default for x86 CPUs
cmake_dependent_option(
  USE_ITT "Use Intel(R) VTune Profiler ITT functionality" ON
  "CPU_INTEL" OFF)
# Ensure that an MKLDNN build is the default for x86 CPUs
# but optional for AArch64 (dependent on -DUSE_MKLDNN).
cmake_dependent_option(
  USE_MKLDNN "Use MKLDNN. Only available on x86, x86_64, and AArch64." "${CPU_INTEL}"
  "CPU_INTEL OR CPU_AARCH64" OFF)
cmake_dependent_option(
  USE_MKLDNN_ACL "Use Compute Library for the Arm architecture." OFF
  "USE_MKLDNN AND CPU_AARCH64" OFF)
set(MKLDNN_ENABLE_CONCURRENT_EXEC ${USE_MKLDNN})
cmake_dependent_option(
    USE_MKLDNN_CBLAS "Use CBLAS in MKLDNN" OFF
    "USE_MKLDNN" OFF)
option(USE_STATIC_MKL "Prefer to link with MKL statically (Unix only)" OFF)
option(USE_DISTRIBUTED "Use distributed" ON)
cmake_dependent_option(
    USE_MPI "Use MPI for Caffe2. Only available if USE_DISTRIBUTED is on." ON
    "USE_DISTRIBUTED" OFF)
cmake_dependent_option(
    USE_UCC "Use UCC. Only available if USE_DISTRIBUTED is on." OFF
    "USE_DISTRIBUTED" OFF)
cmake_dependent_option(
    USE_SYSTEM_UCC "Use system-wide UCC" OFF
    "USE_UCC" OFF)
cmake_dependent_option(
    USE_C10D_UCC "USE C10D UCC" ON "USE_DISTRIBUTED;USE_UCC" OFF)
cmake_dependent_option(
    USE_GLOO "Use Gloo. Only available if USE_DISTRIBUTED is on." ON
    "USE_DISTRIBUTED" OFF)
cmake_dependent_option(
  USE_GLOO_WITH_OPENSSL "Use Gloo with OpenSSL. Only available if USE_GLOO is on." OFF
    "USE_GLOO AND LINUX AND NOT INTERN_BUILD_MOBILE" OFF)
cmake_dependent_option(
    USE_C10D_GLOO "USE C10D GLOO" ON "USE_DISTRIBUTED;USE_GLOO" OFF)
cmake_dependent_option(
    USE_C10D_NCCL "USE C10D NCCL" ON "USE_DISTRIBUTED;USE_NCCL" OFF)
cmake_dependent_option(
    USE_NCCL_WITH_UCC "Enable UCC support for ProcessGroupNCCL. Only available if USE_C10D_NCCL is on." OFF
    "USE_C10D_NCCL" OFF)
cmake_dependent_option(
    USE_C10D_MPI "USE C10D MPI" ON "USE_DISTRIBUTED;USE_MPI" OFF)
cmake_dependent_option(
    USE_TENSORPIPE "Use TensorPipe. Only available if USE_DISTRIBUTED is on." ON
    "USE_DISTRIBUTED" OFF)
option(USE_TBB "Use TBB (Deprecated)" OFF)
cmake_dependent_option(
    USE_SYSTEM_TBB "Use system-provided Intel TBB." OFF "USE_TBB" OFF)
option(ONNX_ML "Enable traditional ONNX ML API." ON)
option(HAVE_SOVERSION "Whether to add SOVERSION to the shared objects" OFF)
option(BUILD_LIBTORCH_CPU_WITH_DEBUG "Enable RelWithDebInfo for libtorch_cpu target only" OFF)
cmake_dependent_option(USE_CCACHE "Attempt using CCache to wrap the compilation" ON "UNIX" OFF)
option(WERROR "Build with -Werror supported by the compiler" OFF)
option(DEBUG_CUDA "When compiling DEBUG, also attempt to compile CUDA with debug flags (may cause nvcc to OOM)" OFF)
option(USE_COREML_DELEGATE "Use the CoreML backend through delegate APIs" OFF)
option(USE_PER_OPERATOR_HEADERS "Whether ATen should generate separate headers for each operator" ON)
cmake_dependent_option(
    BUILD_LAZY_TS_BACKEND "Build the lazy Torchscript backend, not compatible with mobile builds" ON
    "NOT INTERN_BUILD_MOBILE" OFF)
cmake_dependent_option(
    BUILD_FUNCTORCH "Build Functorch" ON "BUILD_PYTHON" OFF)

option(USE_MIMALLOC "Use mimalloc" OFF)
# Enable third party mimalloc library to improve memory allocation performance on Windows.
if(WIN32)
  set(USE_MIMALLOC ON)
endif()

if(USE_CCACHE)
  find_program(CCACHE_PROGRAM ccache)
  if(CCACHE_PROGRAM)
    set(CMAKE_C_COMPILER_LAUNCHER "${CCACHE_PROGRAM}" CACHE STRING "C compiler launcher")
    set(CMAKE_CXX_COMPILER_LAUNCHER "${CCACHE_PROGRAM}" CACHE STRING "CXX compiler launcher")
    set(CMAKE_CUDA_COMPILER_LAUNCHER "${CCACHE_PROGRAM}" CACHE STRING "CUDA compiler launcher")
  else()
    message(STATUS "Could not find ccache. Consider installing ccache to speed up compilation.")
  endif()
endif()

# Since TensorPipe does not support Windows, set it to OFF when WIN32 detected
# On Windows platform, if user does not install libuv in build conda env and
# does not set libuv_ROOT environment variable. Set USE_DISTRIBUTED to OFF.
if(WIN32)
  set(USE_TENSORPIPE OFF)
  message(WARNING "TensorPipe cannot be used on Windows. Set it to OFF")

  if(USE_DISTRIBUTED AND NOT DEFINED ENV{libuv_ROOT})
    find_library(
      libuv_tmp_LIBRARY
      NAMES uv libuv
      HINTS $ENV{CONDA_PREFIX}\\Library $ENV{PREFIX}\\Library
      PATH_SUFFIXES lib
      NO_DEFAULT_PATH)
    if(NOT libuv_tmp_LIBRARY)
      set(USE_DISTRIBUTED OFF)
      set(USE_GLOO OFF)
      message(
        WARNING "Libuv is not installed in current conda env. Set USE_DISTRIBUTED to OFF. "
        "Please run command 'conda install -c conda-forge libuv=1.39' to install libuv.")
    else()
      set(ENV{libuv_ROOT} ${libuv_tmp_LIBRARY}/../../)
    endif()
  endif()
endif()

if(USE_GLOO_WITH_OPENSSL)
  set(USE_TCP_OPENSSL_LOAD ON CACHE STRING "")
endif()

# Linux distributions do not want too many embedded sources, in that sense we
# need to be able to build pytorch with an (almost) empty third_party
# directory.
# USE_SYSTEM_LIBS is a shortcut variable to toggle all the # USE_SYSTEM_*
# variables on. Individual USE_SYSTEM_* variables can be toggled with
# USE_SYSTEM_LIBS being "OFF".
option(USE_SYSTEM_LIBS "Use all available system-provided libraries." OFF)
option(USE_SYSTEM_CPUINFO "Use system-provided cpuinfo." OFF)
option(USE_SYSTEM_SLEEF "Use system-provided sleef." OFF)
option(USE_SYSTEM_GLOO "Use system-provided gloo." OFF)
option(USE_SYSTEM_FP16 "Use system-provided fp16." OFF)
option(USE_SYSTEM_PYBIND11 "Use system-provided PyBind11." OFF)
option(USE_SYSTEM_PTHREADPOOL "Use system-provided pthreadpool." OFF)
option(USE_SYSTEM_PSIMD "Use system-provided psimd." OFF)
option(USE_SYSTEM_FXDIV "Use system-provided fxdiv." OFF)
option(USE_SYSTEM_BENCHMARK "Use system-provided google benchmark." OFF)
option(USE_SYSTEM_ONNX "Use system-provided onnx." OFF)
option(USE_SYSTEM_XNNPACK "Use system-provided xnnpack." OFF)
option(USE_SYSTEM_ZSTD "Use system-provided zstd." OFF)
option(USE_GOLD_LINKER "Use ld.gold to link" OFF)
if(USE_SYSTEM_LIBS)
  set(USE_SYSTEM_CPUINFO ON)
  set(USE_SYSTEM_SLEEF ON)
  set(USE_SYSTEM_GLOO ON)
  set(BUILD_CUSTOM_PROTOBUF OFF)
  set(USE_SYSTEM_EIGEN_INSTALL ON)
  set(USE_SYSTEM_FP16 ON)
  set(USE_SYSTEM_PTHREADPOOL ON)
  set(USE_SYSTEM_PSIMD ON)
  set(USE_SYSTEM_FXDIV ON)
  set(USE_SYSTEM_BENCHMARK ON)
  set(USE_SYSTEM_ONNX ON)
  set(USE_SYSTEM_XNNPACK ON)
  set(USE_SYSTEM_PYBIND11 ON)
  if(USE_NCCL)
    set(USE_SYSTEM_NCCL ON)
  endif()
  if(USE_TBB)
    set(USE_SYSTEM_TBB ON)
  endif()
  if(USE_ZSTD)
    set(USE_SYSTEM_ZSTD ON)
  endif()
endif()

# Used when building Caffe2 through setup.py
option(BUILDING_WITH_TORCH_LIBS "Tell cmake if Caffe2 is being built alongside torch libs" ON)

# /Z7 override option
# When generating debug symbols, CMake default to use the flag /Zi.
# However, it is not compatible with sccache. So we rewrite it off.
# But some users don't use sccache; this override is for them.
cmake_dependent_option(
  MSVC_Z7_OVERRIDE "Work around sccache bug by replacing /Zi and /ZI with /Z7 when using MSVC (if you are not using sccache, you can turn this OFF)" ON
  "MSVC" OFF)

if(NOT USE_SYSTEM_ONNX)
  set(ONNX_NAMESPACE "onnx_torch" CACHE STRING "A namespace for ONNX; needed to build with other frameworks that share ONNX.")
else()
  set(ONNX_NAMESPACE "onnx" CACHE STRING "A namespace for ONNX; needed to build with other frameworks that share ONNX.")
endif()
set(SELECTED_OP_LIST "" CACHE STRING
    "Path to the yaml file that contains the list of operators to include for custom build. Include all operators by default.")
option(
    STATIC_DISPATCH_BACKEND
    "Name of the backend for which static dispatch code is generated, e.g.: CPU."
    "")
option(USE_LIGHTWEIGHT_DISPATCH "Enable codegen unboxing for ATen ops, need to work with static dispatch in order to work properly." OFF)
if(USE_LIGHTWEIGHT_DISPATCH AND NOT STATIC_DISPATCH_BACKEND)
  message(FATAL_ERROR "Need to enable static dispatch after enabling USE_LIGHTWEIGHT_DISPATCH.")
endif()
option(
  TRACING_BASED
  "Master flag to build Lite Interpreter with tracing build option"
  OFF)
option(BUILD_EXECUTORCH "Master flag to build Executorch" ON)
# This is a fix for a rare build issue on Ubuntu:
# symbol lookup error: miniconda3/envs/pytorch-py3.7/lib/libmkl_intel_lp64.so: undefined symbol: mkl_blas_dsyrk
# https://software.intel.com/en-us/articles/symbol-lookup-error-when-linking-intel-mkl-with-gcc-on-ubuntu
if(LINUX)
  set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,--no-as-needed")
endif()

if(MSVC)
  set(CMAKE_NINJA_CMCLDEPS_RC OFF)
  foreach(flag_var
      CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
      CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
      CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
      CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
    # Replace /Zi and /ZI with /Z7
    if(MSVC_Z7_OVERRIDE)
      if(${flag_var} MATCHES "/Z[iI]")
        string(REGEX REPLACE "/Z[iI]" "/Z7" ${flag_var} "${${flag_var}}")
      endif(${flag_var} MATCHES "/Z[iI]")
    endif(MSVC_Z7_OVERRIDE)

    if(${CAFFE2_USE_MSVC_STATIC_RUNTIME})
      if(${flag_var} MATCHES "/MD")
        string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
      endif(${flag_var} MATCHES "/MD")
    else()
      if(${flag_var} MATCHES "/MT")
        string(REGEX REPLACE "/MT" "/MD" ${flag_var} "${${flag_var}}")
      endif()
    endif()

    # /bigobj increases number of sections in .obj file, which is needed to link
    # against libraries in Python 2.7 under Windows
    # For Visual Studio generators, if /MP is not added, then we may need
    # to add /MP to the flags.
    # For other generators like ninja, we don't need to add /MP because it is
    # already handled by the generator itself.
    if(CMAKE_GENERATOR MATCHES "Visual Studio" AND NOT ${flag_var} MATCHES "/MP")
      set(${flag_var} "${${flag_var}} /MP /bigobj")
    else()
      set(${flag_var} "${${flag_var}} /bigobj")
    endif()
  endforeach(flag_var)

  foreach(flag_var
      CMAKE_C_FLAGS CMAKE_C_FLAGS_RELEASE CMAKE_C_FLAGS_MINSIZEREL
      CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_MINSIZEREL)
    if(${flag_var} MATCHES "/Z[iI7]")
      string(REGEX REPLACE "/Z[iI7]" "" ${flag_var} "${${flag_var}}")
    endif()
  endforeach(flag_var)

  foreach(flag_var
      CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO CMAKE_STATIC_LINKER_FLAGS_RELWITHDEBINFO
      CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO CMAKE_MODULE_LINKER_FLAGS_RELWITHDEBINFO
      CMAKE_SHARED_LINKER_FLAGS_DEBUG CMAKE_STATIC_LINKER_FLAGS_DEBUG
      CMAKE_EXE_LINKER_FLAGS_DEBUG CMAKE_MODULE_LINKER_FLAGS_DEBUG)
    # Switch off incremental linking in debug/relwithdebinfo builds
    if(${flag_var} MATCHES "/INCREMENTAL" AND NOT ${flag_var} MATCHES "/INCREMENTAL:NO")
      string(REGEX REPLACE "/INCREMENTAL" "/INCREMENTAL:NO" ${flag_var} "${${flag_var}}")
    endif()
  endforeach(flag_var)

  foreach(flag_var
      CMAKE_SHARED_LINKER_FLAGS CMAKE_STATIC_LINKER_FLAGS
      CMAKE_EXE_LINKER_FLAGS CMAKE_MODULE_LINKER_FLAGS)
    string(APPEND ${flag_var} " /ignore:4049 /ignore:4217 /ignore:4099")
  endforeach(flag_var)

  foreach(flag_var
      CMAKE_SHARED_LINKER_FLAGS)
    # https://github.com/pytorch/pytorch/issues/91933: Don't set the manifest filename
    # explicitly helps fix the linker error when linking torch_python.dll. The manifest
    # file would still be there in the correct format torch_python.dll.manifest
    if(${flag_var} MATCHES "/MANIFESTFILE:.*\\.manifest")
      string(REGEX REPLACE "/MANIFESTFILE:.*\\.manifest" "" ${flag_var} "${${flag_var}}")
    endif()
  endforeach(flag_var)

  # Try harder
  string(APPEND CMAKE_CUDA_FLAGS " -Xcompiler /w -w")

  string(APPEND CMAKE_CXX_FLAGS " /FS")
  string(APPEND CMAKE_CUDA_FLAGS " -Xcompiler /FS")
endif(MSVC)

string(APPEND CMAKE_CUDA_FLAGS " -Xfatbin -compress-all")

# Set INTERN_BUILD_MOBILE for all mobile builds. Components that are not
# applicable to mobile are disabled by this variable.
# Setting `BUILD_PYTORCH_MOBILE_WITH_HOST_TOOLCHAIN` environment variable can
# force it to do mobile build with host toolchain - which is useful for testing
# purpose.
if(ANDROID OR IOS OR DEFINED ENV{BUILD_PYTORCH_MOBILE_WITH_HOST_TOOLCHAIN})
  set(INTERN_BUILD_MOBILE ON)
  message(WARNING "INTERN_BUILD_MOBILE is on, disabling BUILD_LAZY_TS_BACKEND")
  set(BUILD_LAZY_TS_BACKEND OFF)

  # Set -ffunction-sections and -fdata-sections so that each method has its own
  # text section. This allows the linker to remove unused section when the flag
  # -Wl,-gc-sections is provided at link time.
  string(APPEND CMAKE_CXX_FLAGS " -ffunction-sections")
  string(APPEND CMAKE_C_FLAGS " -ffunction-sections")
  string(APPEND CMAKE_CXX_FLAGS " -fdata-sections")
  string(APPEND CMAKE_C_FLAGS " -fdata-sections")

  # Please note that the use of the following flags is required when linking
  # against libtorch_cpu.a for mobile builds.
  # -Wl,--whole-archive -ltorch_cpu -Wl,--no-whole-archive
  #
  # This allows global constructors to be included and run. Global
  # constructors are used for operator/kernel registration with the
  # PyTorch Dispatcher.

  if(DEFINED ENV{BUILD_PYTORCH_MOBILE_WITH_HOST_TOOLCHAIN})
    # C10_MOBILE is derived from Android/iOS toolchain macros in
    # c10/macros/Macros.h, so it needs to be explicitly set here.
    string(APPEND CMAKE_CXX_FLAGS " -DC10_MOBILE")
  endif()

  if(DEFINED ENV{PYTORCH_MOBILE_TRIM_DISPATCH_KEY_SET})
    # If PYTORCH_MOBILE_TRIM_DISPATCH_KEY_SET is defined (env var),
    # then define C10_MOBILE_TRIM_DISPATCH_KEYS, which limits the
    # number of dispatch keys in OperatorEntry::dispatchTable_
    # to reduce peak memory during library initialization.
    string(APPEND CMAKE_CXX_FLAGS " -DC10_MOBILE_TRIM_DISPATCH_KEYS")
  endif()
endif()

# INTERN_BUILD_ATEN_OPS is used to control whether to build ATen/TH operators.
set(INTERN_BUILD_ATEN_OPS ON)

if(NOT DEFINED USE_BLAS)
  set(USE_BLAS ON)
endif()

# Build libtorch mobile library, which contains ATen/TH ops and native support for
# TorchScript model, but doesn't contain not-yet-unified caffe2 ops;
if(INTERN_BUILD_MOBILE)
  if(NOT BUILD_SHARED_LIBS AND NOT "${SELECTED_OP_LIST}" STREQUAL "")
    string(APPEND CMAKE_CXX_FLAGS " -DNO_EXPORT")
  endif()
  if(BUILD_MOBILE_AUTOGRAD)
    set(INTERN_DISABLE_AUTOGRAD OFF)
  else()
    set(INTERN_DISABLE_AUTOGRAD ON)
  endif()
  set(BUILD_PYTHON OFF)
  set(BUILD_FUNCTORCH OFF)
  set(BUILD_CAFFE2_OPS OFF)
  set(USE_DISTRIBUTED OFF)
  set(NO_API ON)
  set(USE_FBGEMM OFF)
  set(USE_QNNPACK OFF)
  set(INTERN_DISABLE_ONNX ON)
  if(USE_BLAS)
    set(INTERN_USE_EIGEN_BLAS ON)
  else()
    set(INTERN_USE_EIGEN_BLAS OFF)
  endif()
  # Disable developing mobile interpreter for actual mobile build.
  # Enable it elsewhere to capture build error.
  set(INTERN_DISABLE_MOBILE_INTERP ON)
endif()

# ---[ Version numbers for generated libraries
file(READ version.txt TORCH_DEFAULT_VERSION)
# Strip trailing newline
string(REGEX REPLACE "\n$" "" TORCH_DEFAULT_VERSION "${TORCH_DEFAULT_VERSION}")
if("${TORCH_DEFAULT_VERSION} " STREQUAL " ")
  message(WARNING "Could not get version from base 'version.txt'")
  # If we can't get the version from the version file we should probably
  # set it to something non-sensical like 0.0.0
  set(TORCH_DEFAULT_VERSION, "0.0.0")
endif()
set(TORCH_BUILD_VERSION "${TORCH_DEFAULT_VERSION}" CACHE STRING "Torch build version")
if(DEFINED ENV{PYTORCH_BUILD_VERSION})
  set(TORCH_BUILD_VERSION "$ENV{PYTORCH_BUILD_VERSION}"
    CACHE STRING "Torch build version" FORCE)
endif()
if(NOT TORCH_BUILD_VERSION)
  # An empty string was specified so force version to the default
  set(TORCH_BUILD_VERSION "${TORCH_DEFAULT_VERSION}"
    CACHE STRING "Torch build version" FORCE)
endif()
caffe2_parse_version_str(TORCH ${TORCH_BUILD_VERSION})
caffe2_parse_version_str(CAFFE2 ${TORCH_BUILD_VERSION})
set(TORCH_SOVERSION "${TORCH_VERSION_MAJOR}.${TORCH_VERSION_MINOR}")

# ---[ CMake scripts + modules
list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake/Modules)

# ---[ CMake build directories
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

enable_testing()

# ---[ Build variables set within the cmake tree
include(cmake/BuildVariables.cmake)
set(CAFFE2_ALLOWLIST "" CACHE STRING "A allowlist file of files that one should build.")

# Set default build type
if(NOT CMAKE_BUILD_TYPE)
    message(STATUS "Build type not set - defaulting to Release")
    set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose the type of build from: Debug Release RelWithDebInfo MinSizeRel Coverage." FORCE)
endif()

# The below means we are cross compiling for arm64 or x86_64 on MacOSX
if(NOT IOS AND CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_ARCHITECTURES MATCHES "^(x86_64|arm64)$")
  set(CROSS_COMPILING_MACOSX TRUE)
  # We need to compile a universal protoc to not fail protobuf build
  # We set CMAKE_TRY_COMPILE_TARGET_TYPE to STATIC_LIBRARY (vs executable) to succeed the cmake compiler check for cross-compiling
  set(protoc_build_command "./scripts/build_host_protoc.sh --other-flags -DCMAKE_OSX_ARCHITECTURES=\"x86_64;arm64\" -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY -DCMAKE_C_COMPILER_WORKS=1 -DCMAKE_CXX_COMPILER_WORKS=1")
  # We write to a temp scriptfile because CMake COMMAND dislikes double quotes in commands
  file(WRITE ${PROJECT_SOURCE_DIR}/tmp_protoc_script.sh "#!/bin/bash\n${protoc_build_command}")
  file(COPY ${PROJECT_SOURCE_DIR}/tmp_protoc_script.sh DESTINATION ${PROJECT_SOURCE_DIR}/scripts/ FILE_PERMISSIONS OWNER_EXECUTE OWNER_WRITE OWNER_READ)
  execute_process(COMMAND ./scripts/tmp_protoc_script.sh
                  WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
                  RESULT_VARIABLE BUILD_HOST_PROTOC_RESULT)
  file(REMOVE ${PROJECT_SOURCE_DIR}/tmp_protoc_script.sh ${PROJECT_SOURCE_DIR}/scripts/tmp_protoc_script.sh)
  if(NOT BUILD_HOST_PROTOC_RESULT EQUAL "0")
    message(FATAL_ERROR "Could not compile universal protoc.")
  endif()
  set(PROTOBUF_PROTOC_EXECUTABLE "${PROJECT_SOURCE_DIR}/build_host_protoc/bin/protoc")
  set(CAFFE2_CUSTOM_PROTOC_EXECUTABLE "${PROJECT_SOURCE_DIR}/build_host_protoc/bin/protoc")
endif()

# ---[ Misc checks to cope with various compiler modes
include(cmake/MiscCheck.cmake)

# External projects
include(ExternalProject)

# ---[ Dependencies
# ---[ FBGEMM doesn't work on x86 32bit and CMAKE_SYSTEM_PROCESSOR thinks its 64bit
if(USE_FBGEMM AND ((CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" AND CMAKE_SIZEOF_VOID_P EQUAL 4) OR CMAKE_SYSTEM_PROCESSOR STREQUAL "x86"))
  set(USE_FBGEMM OFF)
endif()

set(BUILD_ONEDNN_GRAPH OFF)

include(cmake/Dependencies.cmake)

# Moved this cmake set option down here because CMAKE_CUDA_COMPILER_VERSION is not avaialble until now
cmake_dependent_option(
  USE_FLASH_ATTENTION
  "Whether to build the flash_attention kernel for scaled dot product attention" ON
  "USE_CUDA AND NOT ROCM AND NOT CMAKE_CUDA_COMPILER_VERSION VERSION_LESS 11.6" OFF)

if(DEBUG_CUDA)
  string(APPEND CMAKE_CUDA_FLAGS_DEBUG " -lineinfo")
  string(APPEND CMAKE_CUDA_FLAGS_RELWITHDEBINFO " -lineinfo")
  # CUDA-12.1 crashes when trying to compile with --source-in-ptx
  # See https://github.com/pytorch/pytorch/issues/102372#issuecomment-1572526893
  if(CMAKE_CUDA_COMPILER_VERSION VERSION_LESS 12.1)
    string(APPEND CMAKE_CUDA_FLAGS_DEBUG " --source-in-ptx")
    string(APPEND CMAKE_CUDA_FLAGS_RELWITHDEBINFO " --source-in-ptx")
  endif()
endif(DEBUG_CUDA)


if(USE_FBGEMM)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_FBGEMM")
endif()

if(USE_QNNPACK)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_QNNPACK")
endif()

if(USE_PYTORCH_QNNPACK)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_PYTORCH_QNNPACK")
endif()

if(USE_SLEEF_FOR_ARM_VEC256)
  string(APPEND CMAKE_CXX_FLAGS " -DAT_BUILD_ARM_VEC256_WITH_SLEEF")
endif()

if(USE_XNNPACK)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_XNNPACK")
endif()

if(USE_VULKAN)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_VULKAN")
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_VULKAN_API")

  if(USE_VULKAN_FP16_INFERENCE)
    string(APPEND CMAKE_CXX_FLAGS " -DUSE_VULKAN_FP16_INFERENCE")
  endif()

  if(USE_VULKAN_RELAXED_PRECISION)
    string(APPEND CMAKE_CXX_FLAGS " -DUSE_VULKAN_RELAXED_PRECISION")
  endif()

endif()

if(BUILD_LITE_INTERPRETER)
  string(APPEND CMAKE_CXX_FLAGS " -DBUILD_LITE_INTERPRETER")
endif()

if(TRACING_BASED)
  string(APPEND CMAKE_CXX_FLAGS " -DTRACING_BASED")
endif()

if(USE_PYTORCH_METAL)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_PYTORCH_METAL")
endif()

if(USE_PYTORCH_METAL_EXPORT)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_PYTORCH_METAL_EXPORT")
endif()

if(USE_SOURCE_DEBUG_ON_MOBILE)
  string(APPEND CMAKE_CXX_FLAGS " -DSYMBOLICATE_MOBILE_DEBUG_HANDLE")
endif()

if(BUILD_LITE_INTERPRETER AND USE_LITE_INTERPRETER_PROFILER)
  string(APPEND CMAKE_CXX_FLAGS " -DEDGE_PROFILER_USE_KINETO")
endif()

if(USE_COREML_DELEGATE)
  string(APPEND CMAKE_CXX_FLAGS " -DUSE_COREML_DELEGATE")
endif()

# ---[ Allowlist file if allowlist is specified
include(cmake/Allowlist.cmake)

# ---[ Set link flag, handle additional deps for gcc 4.8 and above
if(CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.8.0 AND NOT ANDROID)
  message(STATUS "GCC ${CMAKE_CXX_COMPILER_VERSION}: Adding gcc and gcc_s libs to link line")
  list(APPEND Caffe2_DEPENDENCY_LIBS gcc_s gcc)
endif()

# ---[ Build flags
if(NOT MSVC)
  string(APPEND CMAKE_CXX_FLAGS " -O2 -fPIC")
  # Eigen fails to build with some versions, so convert this to a warning
  # Details at http://eigen.tuxfamily.org/bz/show_bug.cgi?id=1459
  string(APPEND CMAKE_CXX_FLAGS " -Wall")
  string(APPEND CMAKE_CXX_FLAGS " -Wextra")
  append_cxx_flag_if_supported("-Werror=return-type" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Werror=non-virtual-dtor" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Werror=braced-scalar-init" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Werror=range-loop-construct" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Werror=bool-operation" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wnarrowing" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-missing-field-initializers" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-type-limits" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-array-bounds" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-unknown-pragmas" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-unused-parameter" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-unused-function" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-unused-result" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-strict-overflow" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-strict-aliasing" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wvla-extension" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wnewline-eof" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Winconsistent-missing-override" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Winconsistent-missing-destructor-override" CMAKE_CXX_FLAGS)
  if("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
    string(APPEND CMAKE_CXX_FLAGS " -Wno-range-loop-analysis")
    string(APPEND CMAKE_CXX_FLAGS " -Wno-pass-failed")
  endif()
  if(CMAKE_COMPILER_IS_GNUCXX AND NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 7.0.0))
    string(APPEND CMAKE_CXX_FLAGS " -Wno-stringop-overflow")
  endif()
  if(CMAKE_COMPILER_IS_GNUCXX)
    # Suppress "The ABI for passing parameters with 64-byte alignment has changed in GCC 4.6"
    string(APPEND CMAKE_CXX_FLAGS " -Wno-psabi")
  endif()
  if(NOT CMAKE_COMPILER_IS_GNUCXX OR GCC_VERSION VERSION_GREATER_EQUAL 9.2)
    # Prior to GCC 9.2, this warning misfires when a method is
    # labeled "final".
    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78010
    append_cxx_flag_if_supported("-Wsuggest-override" CMAKE_CXX_FLAGS)
  endif()

  # Use ld.gold if available, fall back to ld.bfd (the default ld) if not
  if(USE_GOLD_LINKER)
    if(USE_DISTRIBUTED AND USE_MPI)
      # Same issue as here with default MPI on Ubuntu
      # https://bugs.launchpad.net/ubuntu/+source/deal.ii/+bug/1841577
      message(WARNING "Refusing to use gold when USE_MPI=1")
    else()
      execute_process(
        COMMAND
        "${CMAKE_C_COMPILER}" -fuse-ld=gold -Wl,--version
         ERROR_QUIET
         OUTPUT_VARIABLE LD_VERSION)
      if(NOT "${LD_VERSION}" MATCHES "GNU gold")
        message(WARNING "USE_GOLD_LINKER was set but ld.gold isn't available, turning it off")
        set(USE_GOLD_LINKER OFF)
      else()
        message(STATUS "ld.gold is available, using it to link")
        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fuse-ld=gold")
        set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -fuse-ld=gold")
        set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -fuse-ld=gold")
      endif()
    endif()
  endif()

  append_cxx_flag_if_supported("-Wno-error=pedantic" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-error=old-style-cast" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-error=inconsistent-missing-override" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-error=inconsistent-missing-destructor-override" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wconstant-conversion" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-invalid-partial-specialization" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-unused-private-field" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-aligned-allocation-unavailable" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-missing-braces" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wunused-lambda-capture" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Qunused-arguments" CMAKE_CXX_FLAGS)

  if(${USE_COLORIZE_OUTPUT})
    # Why compiler checks are necessary even when `try_compile` is used
    # Because of the bug in ccache that can incorrectly identify `-fcolor-diagnostics`
    # As supported by GCC, see https://github.com/ccache/ccache/issues/740 (for older ccache)
    # and https://github.com/ccache/ccache/issues/1275 (for newer ones)
    if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
      append_cxx_flag_if_supported("-fdiagnostics-color=always" CMAKE_CXX_FLAGS)
    else()
      append_cxx_flag_if_supported("-fcolor-diagnostics" CMAKE_CXX_FLAGS)
    endif()
  endif()

  append_cxx_flag_if_supported("-faligned-new" CMAKE_CXX_FLAGS)

  if(WERROR)
    append_cxx_flag_if_supported("-Werror" CMAKE_CXX_FLAGS)
    if(NOT COMPILER_SUPPORT_WERROR)
      set(WERROR FALSE)
    endif()
  endif()
  append_cxx_flag_if_supported("-Wno-unused-but-set-variable" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Wno-maybe-uninitialized" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-fstandalone-debug" CMAKE_CXX_FLAGS_DEBUG)
  string(APPEND CMAKE_CXX_FLAGS_DEBUG " -fno-omit-frame-pointer -O0")
  string(APPEND CMAKE_LINKER_FLAGS_DEBUG " -fno-omit-frame-pointer -O0")
  append_cxx_flag_if_supported("-fno-math-errno" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-fno-trapping-math" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Werror=format" CMAKE_CXX_FLAGS)
  append_cxx_flag_if_supported("-Werror=cast-function-type" CMAKE_CXX_FLAGS)
else()
  # skip unwanted includes from windows.h
  add_compile_definitions(WIN32_LEAN_AND_MEAN)
  # Windows SDK broke compatibility since version 25131, but introduced this
  # define for backward compatibility.
  add_compile_definitions(_UCRT_LEGACY_INFINITY)
  # disable min/max macros
  add_compile_definitions(NOMINMAX)
  # The source code is in utf-8 encoding
  append_cxx_flag_if_supported("/utf-8" CMAKE_CXX_FLAGS)
  # Turn off these warnings on Windows.
  # destructor was implicitly defined as delete
  append_cxx_flag_if_supported("/wd4624" CMAKE_CXX_FLAGS)
  # unknown pragma
  append_cxx_flag_if_supported("/wd4068" CMAKE_CXX_FLAGS)
  # unexpected tokens following preprocessor directive - expected a newline
  append_cxx_flag_if_supported("/wd4067" CMAKE_CXX_FLAGS)
  # conversion from 'size_t' to 'unsigned int', possible loss of data
  append_cxx_flag_if_supported("/wd4267" CMAKE_CXX_FLAGS)
  # no suitable definition provided for explicit template instantiation request
  append_cxx_flag_if_supported("/wd4661" CMAKE_CXX_FLAGS)
  # recursive on all control paths, function will cause runtime stack overflow
  append_cxx_flag_if_supported("/wd4717" CMAKE_CXX_FLAGS)
  # conversion from '_Ty' to '_Ty', possible loss of data
  append_cxx_flag_if_supported("/wd4244" CMAKE_CXX_FLAGS)
  # unsafe use of type 'bool' in operation
  append_cxx_flag_if_supported("/wd4804" CMAKE_CXX_FLAGS)
  # inconsistent dll linkage
  append_cxx_flag_if_supported("/wd4273" CMAKE_CXX_FLAGS)
endif()


if(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64")
  include(CheckCSourceCompiles)
  check_c_source_compiles("#include <arm_neon.h>
int main() {
  float a[] = {1.0, 1.0};
  float32x4x2_t v;
  v.val[0] = vcombine_f32 (vcreate_f32 (0UL), vcreate_f32 (0UL));
  v.val[1] = vcombine_f32 (vcreate_f32 (0UL), vcreate_f32 (0UL));
  vst1q_f32_x2(a, v);
  return 0;
}" HAS_VST1)

  if(NOT HAS_VST1)
    string(APPEND CMAKE_CXX_FLAGS " -DMISSING_ARM_VST1")
  endif()
endif()

if(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64")
  include(CheckCSourceCompiles)
  check_c_source_compiles("#include <arm_neon.h>
int main() {
  float a[] = {1.0, 1.0};
  vld1q_f32_x2(a);
  return 0;
}" HAS_VLD1)

  if(NOT HAS_VLD1)
    string(APPEND CMAKE_CXX_FLAGS " -DMISSING_ARM_VLD1")
  endif()
endif()


# Add code coverage flags to supported compilers
if(USE_CPP_CODE_COVERAGE)
  if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
    string(APPEND CMAKE_C_FLAGS  " --coverage -fprofile-abs-path")
    string(APPEND CMAKE_CXX_FLAGS  " --coverage -fprofile-abs-path")
  elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
    string(APPEND CMAKE_C_FLAGS  " -fprofile-instr-generate -fcoverage-mapping")
    string(APPEND CMAKE_CXX_FLAGS " -fprofile-instr-generate -fcoverage-mapping")
  else()
    message(ERROR "Code coverage for compiler ${CMAKE_CXX_COMPILER_ID} is unsupported")
  endif()

endif()

if(APPLE)
    if(USE_MPS)
      string(APPEND CMAKE_OBJCXX_FLAGS " -DUSE_MPS -fno-objc-arc")
      string(APPEND CMAKE_CXX_FLAGS " -DUSE_MPS")
      string(APPEND CMAKE_SHARED_LINKER_FLAGS " -weak_framework Foundation -weak_framework MetalPerformanceShaders -weak_framework MetalPerformanceShadersGraph -weak_framework Metal")
      # To suppress MPSGraph availability warnings
      append_cxx_flag_if_supported("-Wno-unguarded-availability-new" CMAKE_OBJCXX_FLAGS)
    endif()
    append_cxx_flag_if_supported("-Wno-unused-private-field" CMAKE_CXX_FLAGS)
    append_cxx_flag_if_supported("-Wno-missing-braces" CMAKE_CXX_FLAGS)
endif()

if(EMSCRIPTEN)
  string(APPEND CMAKE_CXX_FLAGS " -Wno-implicit-function-declaration -DEMSCRIPTEN -s DISABLE_EXCEPTION_CATCHING=0")
endif()

append_cxx_flag_if_supported("-Wno-stringop-overflow" CMAKE_CXX_FLAGS)

if(ANDROID AND (NOT ANDROID_DEBUG_SYMBOLS))
  if(CMAKE_COMPILER_IS_GNUCXX)
    string(APPEND CMAKE_CXX_FLAGS " -s")
  elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
    string(APPEND CMAKE_CXX_FLAGS " -g0")
  else()
    string(APPEND CMAKE_EXE_LINKER_FLAGS " -s")
  endif()
endif()

if(NOT APPLE AND UNIX)
  list(APPEND Caffe2_DEPENDENCY_LIBS dl)
endif()

# Prefix path to Caffe2 headers.
# If a directory containing installed Caffe2 headers was inadvertently
# added to the list of include directories, prefixing
# PROJECT_SOURCE_DIR means this source tree always takes precedence.
include_directories(BEFORE ${PROJECT_SOURCE_DIR})

# Prefix path to generated Caffe2 headers.
# These need to take precedence over their empty counterparts located
# in PROJECT_SOURCE_DIR.
include_directories(BEFORE ${PROJECT_BINARY_DIR})

include_directories(BEFORE ${PROJECT_SOURCE_DIR}/aten/src/)
include_directories(BEFORE ${PROJECT_BINARY_DIR}/aten/src/)

if(USE_MIMALLOC)
  set(MI_OVERRIDE OFF)
  set(MI_BUILD_SHARED OFF)
  set(MI_BUILD_OBJECT OFF)
  set(MI_BUILD_TESTS OFF)
  add_definitions(-DUSE_MIMALLOC)
  add_subdirectory(third_party/mimalloc)
  include_directories(third_party/mimalloc/include)
endif()

# ---[ Main build
add_subdirectory(c10)
add_subdirectory(caffe2)

# --[ Documentation
if(BUILD_DOCS)
  # check if Doxygen is installed
  find_package(Doxygen)
  if(DOXYGEN_FOUND)
    message("Generating documentation")

    set(DOXYGEN_C_IN ${CMAKE_CURRENT_SOURCE_DIR}/docs/caffe2/.Doxyfile-c)
    set(DOXYGEN_C_OUT ${CMAKE_CURRENT_SOURCE_DIR}/docs/caffe2/Doxyfile-c)
    set(DOXYGEN_P_IN ${CMAKE_CURRENT_SOURCE_DIR}/docs/caffe2/.Doxyfile-python)
    set(DOXYGEN_P_OUT ${CMAKE_CURRENT_SOURCE_DIR}/docs/caffe2/Doxyfile-python)

    if(EXISTS ${CMAKE_CURRENT_BINARY_DIR}/docs)
      file(REMOVE_RECURSE ${CMAKE_CURRENT_BINARY_DIR}/docs)
    endif()

    file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/docs)
    configure_file(${DOXYGEN_C_IN} ${DOXYGEN_C_OUT} @ONLY)
    configure_file(${DOXYGEN_P_IN} ${DOXYGEN_P_OUT} @ONLY)

    add_custom_target(doc_doxygen_c ALL
        COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_C_OUT}
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
        COMMENT "Generating C++ API documentation with Doxygen"
        VERBATIM)

    add_custom_target(doc_doxygen_python ALL
        COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_P_OUT}
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
        COMMENT "Generating Python API documentation with Doxygen"
        VERBATIM)
  else()
    message(FATAL_ERROR "Doxygen needs to be installed to generate the documentation")
  endif()
endif()

# ---[ CMake related files
# Uninistall option.
if(NOT TARGET caffe2_uninstall)
  configure_file(
      ${CMAKE_CURRENT_SOURCE_DIR}/cmake/cmake_uninstall.cmake.in
      ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake
      IMMEDIATE @ONLY)

  add_custom_target(caffe2_uninstall
      COMMAND ${CMAKE_COMMAND} -P
      ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake)
endif()

# ---[ Make configuration files for cmake to allow dependent libraries
# easier access to Caffe2.

if((NOT USE_GLOG) OR (NOT USE_GFLAGS) OR BUILD_CUSTOM_PROTOBUF)
  message(WARNING
      "Generated cmake files are only fully tested if one builds "
      "with system glog, gflags, and protobuf. Other settings may "
      "generate files that are not well tested.")
endif()

if(USE_CUDA OR USE_ROCM)
  # TODO: check if we should include other cuda dependency libraries
  # to the interface as well.

endif()

# Note(jiayq): when building static libraries, all PRIVATE dependencies
# will also become interface libraries, and as a result if there are any
# dependency libraries that are not exported, the following install export
# script will fail. As a result, we will only provide the targets cmake
# files for shared lib installation. For more info, read:
# https://cmake.org/pipermail/cmake/2016-May/063400.html
if(BUILD_SHARED_LIBS)
  configure_file(
      ${PROJECT_SOURCE_DIR}/cmake/Caffe2Config.cmake.in
      ${PROJECT_BINARY_DIR}/Caffe2Config.cmake
      @ONLY)
  install(FILES
      ${PROJECT_BINARY_DIR}/Caffe2Config.cmake
      DESTINATION share/cmake/Caffe2
      COMPONENT dev)
  install(FILES
      ${PROJECT_SOURCE_DIR}/cmake/public/cuda.cmake
      ${PROJECT_SOURCE_DIR}/cmake/public/glog.cmake
      ${PROJECT_SOURCE_DIR}/cmake/public/gflags.cmake
      ${PROJECT_SOURCE_DIR}/cmake/public/mkl.cmake
      ${PROJECT_SOURCE_DIR}/cmake/public/mkldnn.cmake
      ${PROJECT_SOURCE_DIR}/cmake/public/protobuf.cmake
      ${PROJECT_SOURCE_DIR}/cmake/public/utils.cmake
      ${PROJECT_SOURCE_DIR}/cmake/public/LoadHIP.cmake
      DESTINATION share/cmake/Caffe2/public
      COMPONENT dev)
  install(DIRECTORY
      ${PROJECT_SOURCE_DIR}/cmake/Modules_CUDA_fix
      DESTINATION share/cmake/Caffe2/
      COMPONENT dev)
  install(FILES
      ${PROJECT_SOURCE_DIR}/cmake/Modules/FindCUDAToolkit.cmake
      DESTINATION share/cmake/Caffe2/
      COMPONENT dev)
  install(FILES
      ${PROJECT_SOURCE_DIR}/cmake/Modules/FindCUSPARSELT.cmake
      DESTINATION share/cmake/Caffe2/
      COMPONENT dev)

  install(EXPORT Caffe2Targets DESTINATION share/cmake/Caffe2
      FILE Caffe2Targets.cmake
      COMPONENT dev)
else()
  message(WARNING
      "Generated cmake files are only available when building "
      "shared libs.")
endif()

# ---[ Modules
# If master flag for buildling Caffe2 is disabled, we also disable the
# build for Caffe2 related operator modules.
if(BUILD_CAFFE2)
  add_subdirectory(modules)
endif()

# ---[ Binaries
# Binaries will be built after the Caffe2 main libraries and the modules
# are built. For the binaries, they will be linked to the Caffe2 main
# libraries, as well as all the modules that are built with Caffe2 (the ones
# built in the previous Modules section above).
if(BUILD_BINARY)
  add_subdirectory(binaries)
endif()

# ---[ JNI
if(BUILD_JNI)
  if(NOT MSVC)
    string(APPEND CMAKE_CXX_FLAGS " -Wno-unused-variable")
  endif()
  set(BUILD_LIBTORCH_WITH_JNI 1)
  set(FBJNI_SKIP_TESTS 1)
  add_subdirectory(android/pytorch_android)
endif()

if(NOT USE_CUDA AND NOT USE_ROCM)
  set(BUILD_NVFUSER OFF CACHE BOOL "BUILD nvfuser" FORCE)
endif()

if(BUILD_NVFUSER)
  if(DEFINED ENV{NVFUSER_SOURCE_DIR})
    add_subdirectory($ENV{NVFUSER_SOURCE_DIR} nvfuser)
  else()
    add_subdirectory(third_party/nvfuser nvfuser)
  endif()
  add_compile_definitions(BUILD_NVFUSER)
endif()

include(cmake/Summary.cmake)
caffe2_print_configuration_summary()

if(BUILD_FUNCTORCH)
  add_subdirectory(functorch)
endif()