cmake_minimum_required (VERSION 3.13)

# CMake invokes the toolchain file twice during the first build, but only once
# during subsequent rebuilds. This was causing the various flags to be added
# twice on the first build, and on a rebuild ninja would see only one set of the
# flags and rebuild the world.
# https://github.com/android-ndk/ndk/issues/323
if(RISCV_TOOLCHAIN_INCLUDED)
  return()
endif(RISCV_TOOLCHAIN_INCLUDED)
set(RISCV_TOOLCHAIN_INCLUDED true)

set(CMAKE_SYSTEM_PROCESSOR riscv)
set(CMAKE_CROSSCOMPILING ON CACHE BOOL "")

if(CMAKE_HOST_SYSTEM_NAME STREQUAL Linux)
  set(RISCV_HOST_TAG linux)
elseif(CMAKE_HOST_SYSTEM_NAME STREQUAL Darwin)
  set(RISCV_HOST_TAG darwin)
endif()

set(RISCV_TOOLCHAIN_NAME clang)

set(RISCV_TOOLCHAIN_ROOT "$ENV{CACHE}/toolchain_iree_rv32imf" CACHE PATH "RISC-V compiler path")
set(CMAKE_FIND_ROOT_PATH ${RISCV_TOOLCHAIN_ROOT})
list(APPEND CMAKE_PREFIX_PATH "${RISCV_TOOLCHAIN_ROOT}")

set(CMAKE_C_COMPILER "${RISCV_TOOLCHAIN_ROOT}/bin/clang")
set(CMAKE_CXX_COMPILER "${RISCV_TOOLCHAIN_ROOT}/bin/clang++")
set(CMAKE_AR "${RISCV_TOOLCHAIN_ROOT}/bin/llvm-ar")
set(CMAKE_RANLIB "${RISCV_TOOLCHAIN_ROOT}/bin/llvm-ranlib")
set(CMAKE_STRIP "${RISCV_TOOLCHAIN_ROOT}/bin/llvm-strip")

set(RISCV_COMPILER_FLAGS "" CACHE STRING "RISC-V compiler flags for C, CXX, and ASM")
set(RISCV_COMPILER_FLAGS_CXX)
set(RISCV_COMPILER_FLAGS_DEBUG)
set(RISCV_COMPILER_FLAGS_RELEASE)
set(RISCV_LINKER_FLAGS)
set(RISCV_LINKER_FLAGS_EXE)

set(CMAKE_SYSTEM_NAME Generic)
set(CMAKE_C_STANDARD 11)
set(CMAKE_C_EXTENSIONS OFF)     # Force the usage of _ISOC11_SOURCE
set(CMAKE_SYSTEM_LIBRARY_PATH "${RISCV_TOOLCHAIN_ROOT}/riscv32-unknown-elf/lib")
set(RISCV_COMPILER_FLAGS "${RISCV_COMPILER_FLAGS} -menable-experimental-extensions -march=rv32imf_zvl512b_zve32x -mabi=ilp32")

set(CMAKE_C_FLAGS             "${RISCV_COMPILER_FLAGS} ${CMAKE_C_FLAGS}")
set(CMAKE_CXX_FLAGS           "${RISCV_COMPILER_FLAGS} ${RISCV_COMPILER_FLAGS_CXX} ${CMAKE_CXX_FLAGS}")
set(CMAKE_ASM_FLAGS           "${RISCV_COMPILER_FLAGS} ${CMAKE_ASM_FLAGS}")
set(CMAKE_C_FLAGS_DEBUG       "${RISCV_COMPILER_FLAGS_DEBUG} ${CMAKE_C_FLAGS_DEBUG}")
set(CMAKE_CXX_FLAGS_DEBUG     "${RISCV_COMPILER_FLAGS_DEBUG} ${CMAKE_CXX_FLAGS_DEBUG}")
set(CMAKE_ASM_FLAGS_DEBUG     "${RISCV_COMPILER_FLAGS_DEBUG} ${CMAKE_ASM_FLAGS_DEBUG}")
set(CMAKE_C_FLAGS_RELEASE     "${RISCV_COMPILER_FLAGS_RELEASE} ${CMAKE_C_FLAGS_RELEASE}")
set(CMAKE_CXX_FLAGS_RELEASE   "${RISCV_COMPILER_FLAGS_RELEASE} ${CMAKE_CXX_FLAGS_RELEASE}")
set(CMAKE_ASM_FLAGS_RELEASE   "${RISCV_COMPILER_FLAGS_RELEASE} ${CMAKE_ASM_FLAGS_RELEASE}")
set(CMAKE_SHARED_LINKER_FLAGS "${RISCV_LINKER_FLAGS} ${CMAKE_SHARED_LINKER_FLAGS}")
set(CMAKE_MODULE_LINKER_FLAGS "${RISCV_LINKER_FLAGS} ${CMAKE_MODULE_LINKER_FLAGS}")
set(CMAKE_EXE_LINKER_FLAGS    "${RISCV_LINKER_FLAGS} ${RISCV_LINKER_FLAGS_EXE} ${CMAKE_EXE_LINKER_FLAGS}")