CMakeLists.txt

cmake_minimum_required(VERSION 3.16)
project(integral)

# Set the C++ standard and verbosity
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_VERBOSE_MAKEFILE ON)

# Include necessary modules
include(CheckCXXCompilerFlag)
include(CheckCXXSourceRuns)
include(CheckIPOSupported)

# Build options for different architectures
option(BUILD_NATIVE "Build with native optimizations" ON)
option(BUILD_VNNI512 "Build with AVX512 VNNI support" OFF)
option(BUILD_AVX512 "Build with AVX512 optimizations" OFF)
option(BUILD_AVX2_BMI2 "Build with AVX2 + BMI2 optimizations" OFF)
option(BUILD_AVX2 "Build with AVX2 optimizations" OFF)
option(BUILD_SSE41_POPCNT "Build with SSE4.1 + POPCNT optimizations" OFF)
option(BUILD_DEBUG "Build with debug information" OFF)

# Allow user to specify EVALFILE through CMake
set(NETWORK_NAME reshiram)
set(EVALFILE "${EVALFILE}" CACHE STRING "Path to the evaluation (.nnue) file")
set(NNUE_URL "https://github.com/aronpetko/integral-networks/releases/download/${NETWORK_NAME}/${NETWORK_NAME}.nnue")
set(NNUE_PATH "${PROJECT_SOURCE_DIR}/${NETWORK_NAME}.nnue")

# Define the location to download the .nnue file if not provided
if (NOT EVALFILE)
    # Check if the .nnue file exists, if not, download it
    if (NOT EXISTS ${NNUE_PATH})
        message(STATUS "${NETWORK_NAME}.nnue not found. Downloading from ${NNUE_URL}...")
        file(DOWNLOAD ${NNUE_URL} ${NNUE_PATH}
                STATUS DOWNLOAD_STATUS
                SHOW_PROGRESS
        )
        list(GET DOWNLOAD_STATUS 0 DOWNLOAD_STATUS_CODE)
        if (NOT ${DOWNLOAD_STATUS_CODE} EQUAL 0)
            message(FATAL_ERROR "Failed to download ${NETWORK_NAME}.nnue from ${NNUE_URL}")
        endif ()
    else ()
        message(STATUS "${NETWORK_NAME}.nnue already exists. Skipping download.")
    endif ()
    set(EVALFILE ${NNUE_PATH})
else ()
    message(STATUS "Using user-specified EVALFILE: ${EVALFILE}")
endif ()

# Architecture-specific flags
set(CXXFLAGS_NATIVE "-march=native")
set(CXXFLAGS_VNNI512 "-march=znver4 -mtune=znver4 -DBUILD_VNNI512 -DBUILD_FAST_PEXT")
set(CXXFLAGS_AVX512 "-march=x86-64-v4 -mtune=skylake-avx512 -DBUILD_AVX512 -DBUILD_FAST_PEXT")
set(CXXFLAGS_AVX2_BMI2 "-march=haswell -mtune=haswell -mavx2 -mbmi2 -DBUILD_AVX2_BMI2 -DBUILD_FAST_PEXT")
set(CXXFLAGS_AVX2 "-march=bdver4 -mno-tbm -mno-sse4a -mno-bmi2 -mtune=znver2 -DBUILD_AVX2")
set(CXXFLAGS_SSE41_POPCNT "-march=nehalem -mtune=sandybridge -DBUILD_SSE41_POPCNT")

# Apply the correct flags based on the build type
if (BUILD_DEBUG)
    set(CMAKE_BUILD_TYPE Debug)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS_DEBUG} -g -O0")
elseif (BUILD_VNNI512)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXXFLAGS_VNNI512} -DBUILD_VNNI512")
elseif (BUILD_AVX512)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXXFLAGS_AVX512} -DBUILD_AVX512")
elseif (BUILD_AVX2_BMI2)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXXFLAGS_AVX2_BMI2} -DBUILD_AVX2_BMI2")
elseif (BUILD_AVX2)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXXFLAGS_AVX2} -DBUILD_AVX2")
elseif (BUILD_SSE41_POPCNT)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXXFLAGS_SSE41_POPCNT} -DBUILD_SSE41_POPCNT")
elseif (BUILD_NATIVE)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXXFLAGS_NATIVE} -DBUILD_NATIVE")
endif ()

option(DATAGEN OFF)
if (DATAGEN)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DDATAGEN")
endif ()

# Set common flags for release and debug builds
set(CMAKE_CXX_FLAGS_RELEASE "-pthread -O3 -funroll-loops -DNDEBUG")
set(CMAKE_CXX_FLAGS_DEBUG "-pthread -g -O0")

# Check for Link-Time Optimization (LTO) support
check_ipo_supported(RESULT LTO_SUPPORTED)

if (LTO_SUPPORTED)
    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION_RELEASE ON)
    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION_RELWITHDEBINFO OFF)
    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION_DEBUG OFF)
endif ()

# Add Clang-specific flags
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libstdc++")
endif ()

# Static linking on Windows
if (WIN32)
    if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,/STACK:8388608")
    endif ()
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -static")
endif ()

# Include third-party directories
include_directories(third-party/fathom)
include_directories(third-party/fmt/include)
add_definitions(-DFMT_HEADER_ONLY -DEVALFILE="${EVALFILE}")

# Collect all source files
file(GLOB_RECURSE SOURCES "src/*.cc" "src/*.h")

# Create the executable
add_executable(integral ${SOURCES}
        third-party/fathom/tbconfig.h
        third-party/fathom/tbprobe.h
        third-party/fathom/stdendian.h
        third-party/fathom/tbprobe.c
        src/data_gen/data_gen.h
        src/data_gen/format/binpack.h
        src/engine/search/cuckoo.cc)