#
#bsd-kernel
#
#The BSD kernel for any target supported by BSD and the clang (cross)compiler.
#Builds on any host platform supported by clang (ie BSD/Linux/Windows).
#This particular project targets the AMD64 platform, but it can easily be
#retargeted to any platform supported by the LLVM infrastructure and the BSD
#kernel sources. Requires CMake 3.6.3 or later due to the requirements of the
#toolchain file (must generate a static library instead of an executable
#during the compiler verification step because we need to specify the linker).
#

ExternalProject_Add (
  bsd-kernel
  PREFIX ${CMAKE_INSTALL_PREFIX}
  URL http://github.com/freebsd/freebsd/archive/81fb5ce8717f41cc23b2e7d3cea2ab3fc76d85a9.zip
  URL_MD5 5d75275a40c0db6249f56f191bc17d3c
  #
  #Generate CMakeLists.txt in <SOURCE_DIR>/sys
  #
  #PATCH_COMMAND runs with the current directory set to where the source files have been unpacked.
  #bsd-config wants to run with the current directory set to <SOURCE_DIR>/sys/amd64/conf, so change
  #current directory before invoking bsd-config.
  #
  PATCH_COMMAND ${CMAKE_COMMAND} chdir $<SHELL_PATH:<SOURCE_DIR>/sys/amd64/conf> 
     $<SHELL_PATH:<INSTALL_DIR>/bin/bsd-config> #The command to generate the BSD cmake file
     -d $<SHELL_PATH:<SOURCE_DIR>/sys> #Generate CMakeLists.txt in the kernel source directory - required by cmake
     -s $<SHELL_PATH:<SOURCE_DIR>/sys> #The kernel source directory
     $<SHELL_PATH:<SOURCE_DIR>/sys/amd64/conf/GENERIC> #This is the kernel config file we will use to generate a cmake script
  SOURCE_SUBDIR sys #The generated cmake script can be found here when cmake is run during the configure step
  CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
    -DCMAKE_BUILD_TYPE:STRING=Release
    -DCMAKE_TOOLCHAIN_FILE:PATH=${CLANG_FREESTANDING_TOOLCHAIN_FILE}
  DEPENDS clang-toolchain bsd-config bsd-assym uudecode gawk file2c
)