if (APPLE OR SANITIZE STREQUAL "undefined" OR SANITIZE STREQUAL "memory")
    # llvm-tblgen, that is used during LLVM build, doesn't work with UBSan.
    set (ENABLE_EMBEDDED_COMPILER_DEFAULT OFF)
    set (ENABLE_DWARF_PARSER_DEFAULT OFF)
else()
    set (ENABLE_EMBEDDED_COMPILER_DEFAULT ${ENABLE_LIBRARIES})
    set (ENABLE_DWARF_PARSER_DEFAULT ${ENABLE_LIBRARIES})
endif()

option (ENABLE_EMBEDDED_COMPILER "Enable support for JIT compilation during query execution (uses LLVM library)" ${ENABLE_EMBEDDED_COMPILER_DEFAULT})

option (ENABLE_DWARF_PARSER "Enable support for DWARF input format (uses LLVM library)" ${ENABLE_DWARF_PARSER_DEFAULT})

if (NOT ENABLE_EMBEDDED_COMPILER AND NOT ENABLE_DWARF_PARSER)
    message(STATUS "Not using LLVM")
    return()
endif()

set (LLVM_VERSION "15.0.0bundled")
set (LLVM_INCLUDE_DIRS
    "${ClickHouse_SOURCE_DIR}/contrib/llvm-project/llvm/include"
    "${ClickHouse_BINARY_DIR}/contrib/llvm-project/llvm/include"
)
set (LLVM_LIBRARY_DIRS "${ClickHouse_BINARY_DIR}/contrib/llvm-project/llvm")
# NOTE: You should not remove this line since otherwise it will use default 20,
# and llvm cannot be compiled with bundled libcxx and 20 standard.
set (CMAKE_CXX_STANDARD 14)

# This list was generated by listing all LLVM libraries, compiling the binary and removing all libraries while it still compiles.
set (REQUIRED_LLVM_LIBRARIES
    LLVMExecutionEngine
    LLVMRuntimeDyld
    LLVMAsmPrinter
    LLVMDebugInfoDWARF
    LLVMGlobalISel
    LLVMSelectionDAG
    LLVMMCDisassembler
    LLVMPasses
    LLVMCodeGen
    LLVMipo
    LLVMBitWriter
    LLVMInstrumentation
    LLVMScalarOpts
    LLVMAggressiveInstCombine
    LLVMInstCombine
    LLVMVectorize
    LLVMTransformUtils
    LLVMTarget
    LLVMAnalysis
    LLVMProfileData
    LLVMObject
    LLVMBitReader
    LLVMCore
    LLVMRemarks
    LLVMBitstreamReader
    LLVMMCParser
    LLVMMC
    LLVMBinaryFormat
    LLVMDebugInfoCodeView
    LLVMSupport
    LLVMDemangle
)

if (ARCH_AMD64)
    set (LLVM_TARGETS_TO_BUILD "X86" CACHE INTERNAL "")
    list(APPEND REQUIRED_LLVM_LIBRARIES LLVMX86Info LLVMX86Desc LLVMX86CodeGen)
elseif (ARCH_AARCH64)
    set (LLVM_TARGETS_TO_BUILD "AArch64" CACHE INTERNAL "")
    list(APPEND REQUIRED_LLVM_LIBRARIES LLVMAArch64Info LLVMAArch64Desc LLVMAArch64CodeGen)
elseif (ARCH_PPC64LE)
    set (LLVM_TARGETS_TO_BUILD "PowerPC" CACHE INTERNAL "")
    list(APPEND REQUIRED_LLVM_LIBRARIES LLVMPowerPCInfo LLVMPowerPCDesc LLVMPowerPCCodeGen)
elseif (ARCH_S390X)
    set (LLVM_TARGETS_TO_BUILD "SystemZ" CACHE INTERNAL "")
    list(APPEND REQUIRED_LLVM_LIBRARIES LLVMSystemZInfo LLVMSystemZDesc LLVMSystemZCodeGen)
elseif (ARCH_RISCV64)
    set (LLVM_TARGETS_TO_BUILD "RISCV" CACHE INTERNAL "")
    list(APPEND REQUIRED_LLVM_LIBRARIES LLVMRISCVInfo LLVMRISCVDesc LLVMRISCVCodeGen)
endif ()

message (STATUS "LLVM TARGETS TO BUILD ${LLVM_TARGETS_TO_BUILD}")

set (CMAKE_INSTALL_RPATH "ON") # Do not adjust RPATH in llvm, since then it will not be able to find libcxx/libcxxabi/libunwind
set (LLVM_COMPILER_CHECKED 1 CACHE INTERNAL "") # Skip internal compiler selection
set (LLVM_ENABLE_EH 1 CACHE INTERNAL "") # With exception handling
set (LLVM_ENABLE_RTTI 1 CACHE INTERNAL "")
set (LLVM_ENABLE_PIC 0 CACHE INTERNAL "")

# Omit unnecessary stuff (just the options which are ON by default)
set(LLVM_ENABLE_BACKTRACES 0 CACHE INTERNAL "")
set(LLVM_ENABLE_CRASH_OVERRIDES 0 CACHE INTERNAL "")
set(LLVM_ENABLE_TERMINFO 0 CACHE INTERNAL "")
set(LLVM_ENABLE_LIBXML2 0 CACHE INTERNAL "")
set(LLVM_ENABLE_LIBEDIT 0 CACHE INTERNAL "")
set(LLVM_ENABLE_LIBPFM 0 CACHE INTERNAL "")
set(LLVM_ENABLE_ZLIB 0 CACHE INTERNAL "")
set(LLVM_ENABLE_ZSTD 0 CACHE INTERNAL "")
set(LLVM_ENABLE_Z3_SOLVER 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_TOOLS 0 CACHE INTERNAL "")
set(LLVM_BUILD_TOOLS 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_UTILS 0 CACHE INTERNAL "")
set(LLVM_BUILD_UTILS 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_RUNTIMES 0 CACHE INTERNAL "")
set(LLVM_BUILD_RUNTIMES 0 CACHE INTERNAL "")
set(LLVM_BUILD_RUNTIME 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_EXAMPLES 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_TESTS 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_GO_TESTS 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_BENCHMARKS 0 CACHE INTERNAL "")
set(LLVM_INCLUDE_DOCS 0 CACHE INTERNAL "")
set(LLVM_ENABLE_OCAMLDOC 0 CACHE INTERNAL "")
set(LLVM_ENABLE_BINDINGS 0 CACHE INTERNAL "")

set (LLVM_SOURCE_DIR "${ClickHouse_SOURCE_DIR}/contrib/llvm-project/llvm")
set (LLVM_BINARY_DIR "${ClickHouse_BINARY_DIR}/contrib/llvm-project/llvm")

message (STATUS "LLVM CMAKE CROSS COMPILING ${CMAKE_CROSSCOMPILING}")
if (CMAKE_CROSSCOMPILING)
    set (LLVM_HOST_TRIPLE "${CMAKE_C_COMPILER_TARGET}" CACHE INTERNAL "")
    message (STATUS "CROSS COMPILING SET LLVM HOST TRIPLE ${LLVM_HOST_TRIPLE}")
endif()

add_subdirectory ("${LLVM_SOURCE_DIR}" "${LLVM_BINARY_DIR}")

set_directory_properties (PROPERTIES
   # due to llvm crosscompile cmake does not know how to clean it, and on clean
   # will lead to the following error:
   #
   #   ninja: error: remove(contrib/llvm/llvm/NATIVE): Directory not empty
   #
   ADDITIONAL_CLEAN_FILES "${LLVM_BINARY_DIR}"
   # llvm's cmake configuring this file only when cmake runs,
   # and after clean cmake will not know that it should re-run,
   # add explicitly depends from llvm-config.h
   CMAKE_CONFIGURE_DEPENDS "${LLVM_BINARY_DIR}/include/llvm/Config/llvm-config.h"
)

add_library (_llvm INTERFACE)
target_link_libraries (_llvm INTERFACE ${REQUIRED_LLVM_LIBRARIES})
target_include_directories (_llvm SYSTEM BEFORE INTERFACE ${LLVM_INCLUDE_DIRS})
add_library(ch_contrib::llvm ALIAS _llvm)