toolchain_clang_crosscomp_arm.cmake

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#     Author: Kristof Denolf <kristof.denolf@amd.com>
#             Stephen Neuendorffer <stephen.neuendorffer@amd.com>
#     Date:   2018/9/23

# cmake -DCMAKE_TOOLCHAIN_FILE=toolchain_clang_crosscomp_arm.cmake ..
#  -DArch="arm32 or arm64"
#  -DSysroot="absolute path to the sysroot folder"


set(Arch "arm64" CACHE STRING "ARM arch: arm64 or arm32")
set(pythonVer "3.8" CACHE STRING "python version in sysroot")
list(APPEND CMAKE_TRY_COMPILE_PLATFORM_VARIABLES Sysroot Arch pythonVer)

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_LIST_DIR})

#include(toolchain_crosscomp_arm)
# give the system information
SET (CMAKE_SYSTEM_NAME Linux)

if (${Arch} STREQUAL "arm64") # 64 bit toolchain
  SET (CMAKE_SYSTEM_PROCESSOR aarch64)
  SET (gnuPrefix1 aarch64-linux)
  SET (gnuPrefix2 aarch64-linux-gnu)
  SET (gnuArch aarch64-linux-gnu)
  SET (sysrootPrefix aarch64-xilinx-linux)
  #extra compilation flags
  #NONE
else (${Arch} STREQUAL "arm64") #32 bit toolchain
  SET (CMAKE_SYSTEM_PROCESSOR arm)
  SET (gnuPrefix1 gcc-arm-linux-gnueabi)
  SET (gnuPrefix2 arm-linux-gnueabihf)
  SET (gnuArch aarch32)
  SET (sysrootPrefix cortexa9t2hf-neon-xilinx-linux-gnueabi)
  #extra compilation flags
  SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__ARM_PCS_VFP")

endif (${Arch} STREQUAL "arm64")


# specify the cross compiler
# make sure clang is available 
find_program(CLANG_CC clang REQUIRED)

set(CMAKE_C_COMPILER clang)
set(CMAKE_C_COMPILER_TARGET ${gnuArch})
set(CMAKE_CXX_COMPILER clang++)
set(CMAKE_CXX_COMPILER_TARGET ${gnuArch})
set(CMAKE_ASM_COMPILER clang)
set(CMAKE_STRIP llvm-strip)
set(CLANG_LLD lld)

#set compile flags
set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS}" CACHE STRING "" FORCE)
set(CMAKE_ASM_FLAGS "${CMAKE_C_FLAGS}" CACHE STRING "" FORCE)

# set up cross compilation paths
set(CMAKE_SYSROOT ${Sysroot})
set(CMAKE_FIND_ROOT_PATH ${Sysroot})
set(CMAKE_SKIP_BUILD_RPATH FALSE)
set(CMAKE_BUILD_WITH_INSTALL_RPATH TRUE)
# Ensure that we build relocatable binaries
set(CMAKE_INSTALL_RPATH $ORIGIN) #set(CMAKE_INSTALL_RPATH ${Sysroot}/usr/lib/${sysrootPrefix}/11.2.0)
set(CMAKE_LIBRARY_PATH ${Sysroot}/usr/lib)
set(CMAKE_INCLUDE_PATH ${Sysroot}/usr/)
# adjust the default behavior of the find commands:
# search headers and libraries in the target environment
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
# search programs in the host environment
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)

# clang specifics
set(CMAKE_EXE_LINKER_FLAGS "-Wl,-z,notext -fuse-ld=lld" CACHE STRING "" FORCE)
set(CMAKE_SHARED_LINKER_FLAGS "-Wl,-z,notext -fuse-ld=lld" CACHE STRING "" FORCE)

# # Python
# We have to explicitly set this extension.  Normally it would be determined by FindPython3, but
# it's inference mechanism doesn't work when cross-compiling
set(PYTHON_MODULE_EXTENSION ".cpython-38-aarch64-linux-gnu.so")
set(Python3_ROOT_DIR ${Sysroot}/bin)

set(Python_ROOT ${Sysroot}/usr/local/lib/python${pythonVer}/dist-packages)
set(Python3_NumPy_INCLUDE_DIR ${Python_ROOT}/numpy/ CACHE STRING "" FORCE)