set(TILELANG_BACKENDS CUDA ROCM METAL LLVM ASCEND)

set(TILELANG_BACKEND_DOC_CUDA "Enable CUDA backend (ON/OFF/or CUDA SDK path)")

set(TILELANG_BACKEND_DOC_ROCM "Enable ROCm backend (ON/OFF/or ROCm SDK path)")

set(TILELANG_BACKEND_DOC_METAL "Enable Metal backend")

set(TILELANG_BACKEND_DOC_LLVM "Enable LLVM backend")

set(TILELANG_BACKEND_DOC_ASCEND "Enable Ascend backend")

foreach(BACKEND IN LISTS TILELANG_BACKENDS)

set(_backend_var "USE_${BACKEND}")

set(_doc "${TILELANG_BACKEND_DOC_${BACKEND}}")

set(_default OFF)

if(BACKEND STREQUAL "CUDA" AND NOT APPLE AND TILELANG_CUDA_TOOLKIT_AVAILABLE)

set(_default ON)

elseif(BACKEND STREQUAL "METAL" AND APPLE)

set(_default ON)

elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux" AND

(BACKEND STREQUAL "ROCM" OR BACKEND STREQUAL "ASCEND"))

set(_default ON)

endif()

# CMake variables (including cached values and -D arguments) take precedence

# over environment variables. Environment variables initialize a fresh cache.

if(DEFINED ${_backend_var})

set(_default "${${_backend_var}}")

elseif(DEFINED ENV{${_backend_var}})

set(_default "$ENV{${_backend_var}}")

endif()

# STRING preserves SDK paths as well as ON/OFF values.

set(${_backend_var} "${_default}" CACHE STRING "${_doc}")

# TVM's config.cmake redefines USE_* options later. Save the resolved value

# so the caller can restore it after including that configuration.

set(TILELANG_OPTION_${_backend_var} "${${_backend_var}}")

endforeach()