package/llvm/llvm.mk - buildroot - Git at Google

 ################################################################################
 #
 # llvm
 #
 ################################################################################

 # LLVM, Clang and lld should be version bumped together
 LLVM_VERSION = 9.0.1
 LLVM_SITE = https://github.com/llvm/llvm-project/releases/download/llvmorg-$(LLVM_VERSION)
 LLVM_SOURCE = llvm-$(LLVM_VERSION).src.tar.xz
 LLVM_LICENSE = Apache-2.0 with exceptions
 LLVM_LICENSE_FILES = LICENSE.TXT
 LLVM_CPE_ID_VENDOR = $(LLVM_NAME)
 LLVM_SUPPORTS_IN_SOURCE_BUILD = NO
 LLVM_INSTALL_STAGING = YES

 # LLVM >= 9.0 can use python3 to build.
 HOST_LLVM_DEPENDENCIES = host-python3
 LLVM_DEPENDENCIES = host-llvm

 # LLVM >= 9.0 will soon require C++14 support, building llvm 8.x using a
 # toolchain using gcc < 5.1 gives an error but actually still works. Setting
 # this option makes it still build with gcc >= 4.8.
 # https://reviews.llvm.org/D57264
 HOST_LLVM_CONF_OPTS += -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON
 LLVM_CONF_OPTS += -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON

 # Don't build clang libcxx libcxxabi lldb compiler-rt lld polly as llvm subprojects
 # This flag assumes that projects are checked out side-by-side and not nested
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_PROJECTS=""
 LLVM_CONF_OPTS += -DLLVM_ENABLE_PROJECTS=""

 HOST_LLVM_CONF_OPTS += -DLLVM_CCACHE_BUILD=$(if $(BR2_CCACHE),ON,OFF)
 LLVM_CONF_OPTS += -DLLVM_CCACHE_BUILD=$(if $(BR2_CCACHE),ON,OFF)

 # This option prevents AddLLVM.cmake from adding $ORIGIN/../lib to
 # binaries. Otherwise, llvm-config (host variant installed in STAGING)
 # will try to use target's libc.
 HOST_LLVM_CONF_OPTS += -DCMAKE_INSTALL_RPATH="$(HOST_DIR)/lib"

 # Get target architecture
 LLVM_TARGET_ARCH = $(call qstrip,$(BR2_PACKAGE_LLVM_TARGET_ARCH))

 # Build backend for target architecture. This include backends like AMDGPU.
 LLVM_TARGETS_TO_BUILD = $(LLVM_TARGET_ARCH)
 HOST_LLVM_CONF_OPTS += -DLLVM_TARGETS_TO_BUILD="$(subst $(space),;,$(LLVM_TARGETS_TO_BUILD))"
 LLVM_CONF_OPTS += -DLLVM_TARGETS_TO_BUILD="$(subst $(space),;,$(LLVM_TARGETS_TO_BUILD))"

 # LLVM target to use for native code generation. This is required for JIT generation.
 # It must be set to LLVM_TARGET_ARCH for host and target, otherwise we get
 # "No available targets are compatible for this triple" with llvmpipe when host
 # and target architectures are different.
 HOST_LLVM_CONF_OPTS += -DLLVM_TARGET_ARCH=$(LLVM_TARGET_ARCH)
 LLVM_CONF_OPTS += -DLLVM_TARGET_ARCH=$(LLVM_TARGET_ARCH)

 # Build AMDGPU backend
 # We need to build AMDGPU backend for both host and target because
 # llvm-config --targets built (host variant installed in STAGING) will
 # output only $(LLVM_TARGET_ARCH) if not, and mesa3d won't build as
 # it thinks AMDGPU backend is not installed on the target.
 ifeq ($(BR2_PACKAGE_LLVM_AMDGPU),y)
 LLVM_TARGETS_TO_BUILD += AMDGPU
 endif

 # Use native llvm-tblgen from host-llvm (needed for cross-compilation)
 LLVM_CONF_OPTS += -DLLVM_TABLEGEN=$(HOST_DIR)/bin/llvm-tblgen

 # Use native llvm-config from host-llvm (needed for cross-compilation)
 LLVM_CONF_OPTS += -DLLVM_CONFIG_PATH=$(HOST_DIR)/bin/llvm-config

 # BUILD_SHARED_LIBS has a misleading name. It is in fact an option for
 # LLVM developers to build all LLVM libraries as separate shared libraries.
 # For normal use of LLVM, it is recommended to build a single
 # shared library, which is achieved by BUILD_SHARED_LIBS=OFF and
 # LLVM_BUILD_LLVM_DYLIB=ON.
 HOST_LLVM_CONF_OPTS += -DBUILD_SHARED_LIBS=OFF
 LLVM_CONF_OPTS += -DBUILD_SHARED_LIBS=OFF

 # Generate libLLVM.so. This library contains a default set of LLVM components
 # that can be overwritten with "LLVM_DYLIB_COMPONENTS". The default contains
 # most of LLVM and is defined in "tools/llvm-shlib/CMakelists.txt".
 HOST_LLVM_CONF_OPTS += -DLLVM_BUILD_LLVM_DYLIB=ON
 LLVM_CONF_OPTS += -DLLVM_BUILD_LLVM_DYLIB=ON

 # LLVM_BUILD_LLVM_DYLIB to ON. We need to enable this option for the
 # host as llvm-config for the host will be used in STAGING_DIR by packages
 # linking against libLLVM and if this option is not selected, then llvm-config
 # does not work properly. For example, it assumes that LLVM is built statically
 # and cannot find libLLVM.so.
 HOST_LLVM_CONF_OPTS += -DLLVM_LINK_LLVM_DYLIB=ON
 LLVM_CONF_OPTS += -DLLVM_LINK_LLVM_DYLIB=ON

 LLVM_CONF_OPTS += -DCMAKE_CROSSCOMPILING=1

 # Disabled for the host since no host-libedit.
 # Fall back to "Simple fgets-based implementation" of llvm line editor.
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBEDIT=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBEDIT=OFF

 # We want to install llvm libraries and modules.
 HOST_LLVM_CONF_OPTS += -DLLVM_INSTALL_TOOLCHAIN_ONLY=OFF
 LLVM_CONF_OPTS += -DLLVM_INSTALL_TOOLCHAIN_ONLY=OFF

 # We build from a release archive without vcs files.
 HOST_LLVM_CONF_OPTS += -DLLVM_APPEND_VC_REV=OFF
 LLVM_CONF_OPTS += -DLLVM_APPEND_VC_REV=OFF

 # No backtrace package in Buildroot.
 # https://documentation.backtrace.io
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_BACKTRACES=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_BACKTRACES=OFF

 # Enable signal handlers overrides support.
 HOST_LLVM_CONF_OPTS += -DENABLE_CRASH_OVERRIDES=ON
 LLVM_CONF_OPTS += -DENABLE_CRASH_OVERRIDES=ON

 # Disable ffi for now.
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_FFI=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_FFI=OFF

 # Disable terminfo database (needs ncurses libtinfo.so)
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_TERMINFO=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_TERMINFO=OFF

 # Enable thread support
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_THREADS=ON
 LLVM_CONF_OPTS += -DLLVM_ENABLE_THREADS=ON

 # Enable optional host-zlib support for LLVM Machine Code (llvm-mc) to add
 # compression/uncompression capabilities.
 # Not needed on the target.
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_ZLIB=ON
 HOST_LLVM_DEPENDENCIES += host-zlib
 LLVM_CONF_OPTS += -DLLVM_ENABLE_ZLIB=OFF

 # libxml2 can be disabled as it is used for LLVM Windows builds where COFF
 # files include manifest info
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBXML2=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBXML2=OFF

 # Disable optional Z3Prover since there is no such package in Buildroot.
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_Z3_SOLVER=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_Z3_SOLVER=OFF

 # We don't use llvm for static only build, so enable PIC
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_PIC=ON
 LLVM_CONF_OPTS += -DLLVM_ENABLE_PIC=ON

 # Default is Debug build, which requires considerably more disk space and
 # build time. Release build is selected for host and target because the linker
 # can run out of memory in Debug mode.
 HOST_LLVM_CONF_OPTS += -DCMAKE_BUILD_TYPE=Release
 LLVM_CONF_OPTS += -DCMAKE_BUILD_TYPE=Release

 # Disable C++1y (ISO C++ 2014 standard)
 # Disable C++1z (ISO C++ 2017 standard)
 # Compile llvm with the C++11 (ISO C++ 2011 standard) which is the fallback.
 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_ENABLE_CXX1Y=OFF \
 	-DLLVM_ENABLE_CXX1Z=OFF
 LLVM_CONF_OPTS += \
 	-DLLVM_ENABLE_CXX1Y=OFF \
 	-DLLVM_ENABLE_CXX1Z=OFF

 # Disabled, requires sys/ndir.h header
 # Disable debug in module
 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_ENABLE_MODULES=OFF \
 	-DLLVM_ENABLE_MODULE_DEBUGGING=OFF
 LLVM_CONF_OPTS += \
 	-DLLVM_ENABLE_MODULES=OFF \
 	-DLLVM_ENABLE_MODULE_DEBUGGING=OFF

 # Don't change the standard library to libc++.
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBCXX=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBCXX=OFF

 # Don't use lld as a linker.
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LLD=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_LLD=OFF

 # Generate code for the target. LLVM selects a target by looking at the
 # toolchain tuple
 HOST_LLVM_CONF_OPTS += -DLLVM_DEFAULT_TARGET_TRIPLE=$(GNU_TARGET_NAME)
 LLVM_CONF_OPTS += -DLLVM_DEFAULT_TARGET_TRIPLE=$(GNU_TARGET_NAME)

 # LLVM_HOST_TRIPLE has a misleading name, it is in fact the triple of the
 # system where llvm is going to run on. We need to specify triple for native
 # code generation on the target.
 # This solves "No available targets are compatible for this triple" with llvmpipe
 LLVM_CONF_OPTS += -DLLVM_HOST_TRIPLE=$(GNU_TARGET_NAME)

 # Building the Go and OCaml bindings is yet unsupported.
 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_ENABLE_BINDINGS=OFF

 # Builds a release host tablegen that gets used during the LLVM build.
 HOST_LLVM_CONF_OPTS += -DLLVM_OPTIMIZED_TABLEGEN=ON

 # Keep llvm utility binaries for the host. llvm-tblgen is built anyway as
 # CMakeLists.txt has add_subdirectory(utils/TableGen) unconditionally.
 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_BUILD_UTILS=ON \
 	-DLLVM_INCLUDE_UTILS=ON \
 	-DLLVM_INSTALL_UTILS=ON
 LLVM_CONF_OPTS += \
 	-DLLVM_BUILD_UTILS=OFF \
 	-DLLVM_INCLUDE_UTILS=OFF \
 	-DLLVM_INSTALL_UTILS=OFF

 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_INCLUDE_TOOLS=ON \
 	-DLLVM_BUILD_TOOLS=ON

 # We need to activate LLVM_INCLUDE_TOOLS, otherwise it does not generate
 # libLLVM.so
 LLVM_CONF_OPTS += \
 	-DLLVM_INCLUDE_TOOLS=ON \
 	-DLLVM_BUILD_TOOLS=OFF

 ifeq ($(BR2_PACKAGE_LLVM_RTTI),y)
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=ON
 LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=ON
 else
 HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=OFF
 LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=OFF
 endif

 # Compiler-rt not in the source tree.
 # llvm runtime libraries are not in the source tree.
 # Polly is not in the source tree.
 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_BUILD_EXTERNAL_COMPILER_RT=OFF \
 	-DLLVM_BUILD_RUNTIME=OFF \
 	-DLLVM_INCLUDE_RUNTIMES=OFF \
 	-DLLVM_POLLY_BUILD=OFF
 LLVM_CONF_OPTS += \
 	-DLLVM_BUILD_EXTERNAL_COMPILER_RT=OFF \
 	-DLLVM_BUILD_RUNTIME=OFF \
 	-DLLVM_INCLUDE_RUNTIMES=OFF \
 	-DLLVM_POLLY_BUILD=OFF

 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_ENABLE_WARNINGS=ON \
 	-DLLVM_ENABLE_PEDANTIC=ON \
 	-DLLVM_ENABLE_WERROR=OFF
 LLVM_CONF_OPTS += \
 	-DLLVM_ENABLE_WARNINGS=ON \
 	-DLLVM_ENABLE_PEDANTIC=ON \
 	-DLLVM_ENABLE_WERROR=OFF

 HOST_LLVM_CONF_OPTS += \
 	-DLLVM_BUILD_EXAMPLES=OFF \
 	-DLLVM_BUILD_DOCS=OFF \
 	-DLLVM_BUILD_TESTS=OFF \
 	-DLLVM_ENABLE_DOXYGEN=OFF \
 	-DLLVM_ENABLE_OCAMLDOC=OFF \
 	-DLLVM_ENABLE_SPHINX=OFF \
 	-DLLVM_INCLUDE_EXAMPLES=OFF \
 	-DLLVM_INCLUDE_DOCS=OFF \
 	-DLLVM_INCLUDE_GO_TESTS=OFF \
 	-DLLVM_INCLUDE_TESTS=OFF
 LLVM_CONF_OPTS += \
 	-DLLVM_BUILD_EXAMPLES=OFF \
 	-DLLVM_BUILD_DOCS=OFF \
 	-DLLVM_BUILD_TESTS=OFF \
 	-DLLVM_ENABLE_DOXYGEN=OFF \
 	-DLLVM_ENABLE_OCAMLDOC=OFF \
 	-DLLVM_ENABLE_SPHINX=OFF \
 	-DLLVM_INCLUDE_EXAMPLES=OFF \
 	-DLLVM_INCLUDE_DOCS=OFF \
 	-DLLVM_INCLUDE_GO_TESTS=OFF \
 	-DLLVM_INCLUDE_TESTS=OFF

 # Copy llvm-config (host variant) to STAGING_DIR
 # llvm-config (host variant) returns include and lib directories
 # for the host if it's installed in host/bin:
 # output/host/bin/llvm-config --includedir
 # output/host/include
 # When installed in STAGING_DIR, llvm-config returns include and lib
 # directories from STAGING_DIR.
 # output/staging/usr/bin/llvm-config --includedir
 # output/staging/usr/include
 define HOST_LLVM_COPY_LLVM_CONFIG_TO_STAGING_DIR
 	$(INSTALL) -D -m 0755 $(HOST_DIR)/bin/llvm-config \
 		$(STAGING_DIR)/usr/bin/llvm-config
 endef
 HOST_LLVM_POST_INSTALL_HOOKS = HOST_LLVM_COPY_LLVM_CONFIG_TO_STAGING_DIR

 # By default llvm-tblgen is built and installed on the target but it is
 # not necessary. Also erase LLVMHello.so from /usr/lib
 define LLVM_DELETE_LLVM_TBLGEN_TARGET
 	rm -f $(TARGET_DIR)/usr/bin/llvm-tblgen $(TARGET_DIR)/usr/lib/LLVMHello.so
 endef
 LLVM_POST_INSTALL_TARGET_HOOKS = LLVM_DELETE_LLVM_TBLGEN_TARGET

 $(eval $(cmake-package))
 $(eval $(host-cmake-package))
	################################################################################
	#
	# llvm
	#
	################################################################################

	# LLVM, Clang and lld should be version bumped together
	LLVM_VERSION = 9.0.1
	LLVM_SITE = https://github.com/llvm/llvm-project/releases/download/llvmorg-$(LLVM_VERSION)
	LLVM_SOURCE = llvm-$(LLVM_VERSION).src.tar.xz
	LLVM_LICENSE = Apache-2.0 with exceptions
	LLVM_LICENSE_FILES = LICENSE.TXT
	LLVM_CPE_ID_VENDOR = $(LLVM_NAME)
	LLVM_SUPPORTS_IN_SOURCE_BUILD = NO
	LLVM_INSTALL_STAGING = YES

	# LLVM >= 9.0 can use python3 to build.
	HOST_LLVM_DEPENDENCIES = host-python3
	LLVM_DEPENDENCIES = host-llvm

	# LLVM >= 9.0 will soon require C++14 support, building llvm 8.x using a
	# toolchain using gcc < 5.1 gives an error but actually still works. Setting
	# this option makes it still build with gcc >= 4.8.
	# https://reviews.llvm.org/D57264
	HOST_LLVM_CONF_OPTS += -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON
	LLVM_CONF_OPTS += -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON

	# Don't build clang libcxx libcxxabi lldb compiler-rt lld polly as llvm subprojects
	# This flag assumes that projects are checked out side-by-side and not nested
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_PROJECTS=""
	LLVM_CONF_OPTS += -DLLVM_ENABLE_PROJECTS=""

	HOST_LLVM_CONF_OPTS += -DLLVM_CCACHE_BUILD=$(if $(BR2_CCACHE),ON,OFF)
	LLVM_CONF_OPTS += -DLLVM_CCACHE_BUILD=$(if $(BR2_CCACHE),ON,OFF)

	# This option prevents AddLLVM.cmake from adding $ORIGIN/../lib to
	# binaries. Otherwise, llvm-config (host variant installed in STAGING)
	# will try to use target's libc.
	HOST_LLVM_CONF_OPTS += -DCMAKE_INSTALL_RPATH="$(HOST_DIR)/lib"

	# Get target architecture
	LLVM_TARGET_ARCH = $(call qstrip,$(BR2_PACKAGE_LLVM_TARGET_ARCH))

	# Build backend for target architecture. This include backends like AMDGPU.
	LLVM_TARGETS_TO_BUILD = $(LLVM_TARGET_ARCH)
	HOST_LLVM_CONF_OPTS += -DLLVM_TARGETS_TO_BUILD="$(subst $(space),;,$(LLVM_TARGETS_TO_BUILD))"
	LLVM_CONF_OPTS += -DLLVM_TARGETS_TO_BUILD="$(subst $(space),;,$(LLVM_TARGETS_TO_BUILD))"

	# LLVM target to use for native code generation. This is required for JIT generation.
	# It must be set to LLVM_TARGET_ARCH for host and target, otherwise we get
	# "No available targets are compatible for this triple" with llvmpipe when host
	# and target architectures are different.
	HOST_LLVM_CONF_OPTS += -DLLVM_TARGET_ARCH=$(LLVM_TARGET_ARCH)
	LLVM_CONF_OPTS += -DLLVM_TARGET_ARCH=$(LLVM_TARGET_ARCH)

	# Build AMDGPU backend
	# We need to build AMDGPU backend for both host and target because
	# llvm-config --targets built (host variant installed in STAGING) will
	# output only $(LLVM_TARGET_ARCH) if not, and mesa3d won't build as
	# it thinks AMDGPU backend is not installed on the target.
	ifeq ($(BR2_PACKAGE_LLVM_AMDGPU),y)
	LLVM_TARGETS_TO_BUILD += AMDGPU
	endif

	# Use native llvm-tblgen from host-llvm (needed for cross-compilation)
	LLVM_CONF_OPTS += -DLLVM_TABLEGEN=$(HOST_DIR)/bin/llvm-tblgen

	# Use native llvm-config from host-llvm (needed for cross-compilation)
	LLVM_CONF_OPTS += -DLLVM_CONFIG_PATH=$(HOST_DIR)/bin/llvm-config

	# BUILD_SHARED_LIBS has a misleading name. It is in fact an option for
	# LLVM developers to build all LLVM libraries as separate shared libraries.
	# For normal use of LLVM, it is recommended to build a single
	# shared library, which is achieved by BUILD_SHARED_LIBS=OFF and
	# LLVM_BUILD_LLVM_DYLIB=ON.
	HOST_LLVM_CONF_OPTS += -DBUILD_SHARED_LIBS=OFF
	LLVM_CONF_OPTS += -DBUILD_SHARED_LIBS=OFF

	# Generate libLLVM.so. This library contains a default set of LLVM components
	# that can be overwritten with "LLVM_DYLIB_COMPONENTS". The default contains
	# most of LLVM and is defined in "tools/llvm-shlib/CMakelists.txt".
	HOST_LLVM_CONF_OPTS += -DLLVM_BUILD_LLVM_DYLIB=ON
	LLVM_CONF_OPTS += -DLLVM_BUILD_LLVM_DYLIB=ON

	# LLVM_BUILD_LLVM_DYLIB to ON. We need to enable this option for the
	# host as llvm-config for the host will be used in STAGING_DIR by packages
	# linking against libLLVM and if this option is not selected, then llvm-config
	# does not work properly. For example, it assumes that LLVM is built statically
	# and cannot find libLLVM.so.
	HOST_LLVM_CONF_OPTS += -DLLVM_LINK_LLVM_DYLIB=ON
	LLVM_CONF_OPTS += -DLLVM_LINK_LLVM_DYLIB=ON

	LLVM_CONF_OPTS += -DCMAKE_CROSSCOMPILING=1

	# Disabled for the host since no host-libedit.
	# Fall back to "Simple fgets-based implementation" of llvm line editor.
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBEDIT=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBEDIT=OFF

	# We want to install llvm libraries and modules.
	HOST_LLVM_CONF_OPTS += -DLLVM_INSTALL_TOOLCHAIN_ONLY=OFF
	LLVM_CONF_OPTS += -DLLVM_INSTALL_TOOLCHAIN_ONLY=OFF

	# We build from a release archive without vcs files.
	HOST_LLVM_CONF_OPTS += -DLLVM_APPEND_VC_REV=OFF
	LLVM_CONF_OPTS += -DLLVM_APPEND_VC_REV=OFF

	# No backtrace package in Buildroot.
	# https://documentation.backtrace.io
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_BACKTRACES=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_BACKTRACES=OFF

	# Enable signal handlers overrides support.
	HOST_LLVM_CONF_OPTS += -DENABLE_CRASH_OVERRIDES=ON
	LLVM_CONF_OPTS += -DENABLE_CRASH_OVERRIDES=ON

	# Disable ffi for now.
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_FFI=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_FFI=OFF

	# Disable terminfo database (needs ncurses libtinfo.so)
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_TERMINFO=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_TERMINFO=OFF

	# Enable thread support
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_THREADS=ON
	LLVM_CONF_OPTS += -DLLVM_ENABLE_THREADS=ON

	# Enable optional host-zlib support for LLVM Machine Code (llvm-mc) to add
	# compression/uncompression capabilities.
	# Not needed on the target.
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_ZLIB=ON
	HOST_LLVM_DEPENDENCIES += host-zlib
	LLVM_CONF_OPTS += -DLLVM_ENABLE_ZLIB=OFF

	# libxml2 can be disabled as it is used for LLVM Windows builds where COFF
	# files include manifest info
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBXML2=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBXML2=OFF

	# Disable optional Z3Prover since there is no such package in Buildroot.
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_Z3_SOLVER=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_Z3_SOLVER=OFF

	# We don't use llvm for static only build, so enable PIC
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_PIC=ON
	LLVM_CONF_OPTS += -DLLVM_ENABLE_PIC=ON

	# Default is Debug build, which requires considerably more disk space and
	# build time. Release build is selected for host and target because the linker
	# can run out of memory in Debug mode.
	HOST_LLVM_CONF_OPTS += -DCMAKE_BUILD_TYPE=Release
	LLVM_CONF_OPTS += -DCMAKE_BUILD_TYPE=Release

	# Disable C++1y (ISO C++ 2014 standard)
	# Disable C++1z (ISO C++ 2017 standard)
	# Compile llvm with the C++11 (ISO C++ 2011 standard) which is the fallback.
	HOST_LLVM_CONF_OPTS += \
	-DLLVM_ENABLE_CXX1Y=OFF \
	-DLLVM_ENABLE_CXX1Z=OFF
	LLVM_CONF_OPTS += \
	-DLLVM_ENABLE_CXX1Y=OFF \
	-DLLVM_ENABLE_CXX1Z=OFF

	# Disabled, requires sys/ndir.h header
	# Disable debug in module
	HOST_LLVM_CONF_OPTS += \
	-DLLVM_ENABLE_MODULES=OFF \
	-DLLVM_ENABLE_MODULE_DEBUGGING=OFF
	LLVM_CONF_OPTS += \
	-DLLVM_ENABLE_MODULES=OFF \
	-DLLVM_ENABLE_MODULE_DEBUGGING=OFF

	# Don't change the standard library to libc++.
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBCXX=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_LIBCXX=OFF

	# Don't use lld as a linker.
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_LLD=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_LLD=OFF

	# Generate code for the target. LLVM selects a target by looking at the
	# toolchain tuple
	HOST_LLVM_CONF_OPTS += -DLLVM_DEFAULT_TARGET_TRIPLE=$(GNU_TARGET_NAME)
	LLVM_CONF_OPTS += -DLLVM_DEFAULT_TARGET_TRIPLE=$(GNU_TARGET_NAME)

	# LLVM_HOST_TRIPLE has a misleading name, it is in fact the triple of the
	# system where llvm is going to run on. We need to specify triple for native
	# code generation on the target.
	# This solves "No available targets are compatible for this triple" with llvmpipe
	LLVM_CONF_OPTS += -DLLVM_HOST_TRIPLE=$(GNU_TARGET_NAME)

	# Building the Go and OCaml bindings is yet unsupported.
	HOST_LLVM_CONF_OPTS += \
	-DLLVM_ENABLE_BINDINGS=OFF

	# Builds a release host tablegen that gets used during the LLVM build.
	HOST_LLVM_CONF_OPTS += -DLLVM_OPTIMIZED_TABLEGEN=ON

	# Keep llvm utility binaries for the host. llvm-tblgen is built anyway as
	# CMakeLists.txt has add_subdirectory(utils/TableGen) unconditionally.
	HOST_LLVM_CONF_OPTS += \
	-DLLVM_BUILD_UTILS=ON \
	-DLLVM_INCLUDE_UTILS=ON \
	-DLLVM_INSTALL_UTILS=ON
	LLVM_CONF_OPTS += \
	-DLLVM_BUILD_UTILS=OFF \
	-DLLVM_INCLUDE_UTILS=OFF \
	-DLLVM_INSTALL_UTILS=OFF

	HOST_LLVM_CONF_OPTS += \
	-DLLVM_INCLUDE_TOOLS=ON \
	-DLLVM_BUILD_TOOLS=ON

	# We need to activate LLVM_INCLUDE_TOOLS, otherwise it does not generate
	# libLLVM.so
	LLVM_CONF_OPTS += \
	-DLLVM_INCLUDE_TOOLS=ON \
	-DLLVM_BUILD_TOOLS=OFF

	ifeq ($(BR2_PACKAGE_LLVM_RTTI),y)
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=ON
	LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=ON
	else
	HOST_LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=OFF
	LLVM_CONF_OPTS += -DLLVM_ENABLE_RTTI=OFF
	endif

	# Compiler-rt not in the source tree.
	# llvm runtime libraries are not in the source tree.
	# Polly is not in the source tree.
	HOST_LLVM_CONF_OPTS += \
	-DLLVM_BUILD_EXTERNAL_COMPILER_RT=OFF \
	-DLLVM_BUILD_RUNTIME=OFF \
	-DLLVM_INCLUDE_RUNTIMES=OFF \
	-DLLVM_POLLY_BUILD=OFF
	LLVM_CONF_OPTS += \
	-DLLVM_BUILD_EXTERNAL_COMPILER_RT=OFF \
	-DLLVM_BUILD_RUNTIME=OFF \
	-DLLVM_INCLUDE_RUNTIMES=OFF \
	-DLLVM_POLLY_BUILD=OFF

	HOST_LLVM_CONF_OPTS += \
	-DLLVM_ENABLE_WARNINGS=ON \
	-DLLVM_ENABLE_PEDANTIC=ON \
	-DLLVM_ENABLE_WERROR=OFF
	LLVM_CONF_OPTS += \
	-DLLVM_ENABLE_WARNINGS=ON \
	-DLLVM_ENABLE_PEDANTIC=ON \
	-DLLVM_ENABLE_WERROR=OFF

	HOST_LLVM_CONF_OPTS += \
	-DLLVM_BUILD_EXAMPLES=OFF \
	-DLLVM_BUILD_DOCS=OFF \
	-DLLVM_BUILD_TESTS=OFF \
	-DLLVM_ENABLE_DOXYGEN=OFF \
	-DLLVM_ENABLE_OCAMLDOC=OFF \
	-DLLVM_ENABLE_SPHINX=OFF \
	-DLLVM_INCLUDE_EXAMPLES=OFF \
	-DLLVM_INCLUDE_DOCS=OFF \
	-DLLVM_INCLUDE_GO_TESTS=OFF \
	-DLLVM_INCLUDE_TESTS=OFF
	LLVM_CONF_OPTS += \
	-DLLVM_BUILD_EXAMPLES=OFF \
	-DLLVM_BUILD_DOCS=OFF \
	-DLLVM_BUILD_TESTS=OFF \
	-DLLVM_ENABLE_DOXYGEN=OFF \
	-DLLVM_ENABLE_OCAMLDOC=OFF \
	-DLLVM_ENABLE_SPHINX=OFF \
	-DLLVM_INCLUDE_EXAMPLES=OFF \
	-DLLVM_INCLUDE_DOCS=OFF \
	-DLLVM_INCLUDE_GO_TESTS=OFF \
	-DLLVM_INCLUDE_TESTS=OFF

	# Copy llvm-config (host variant) to STAGING_DIR
	# llvm-config (host variant) returns include and lib directories
	# for the host if it's installed in host/bin:
	# output/host/bin/llvm-config --includedir
	# output/host/include
	# When installed in STAGING_DIR, llvm-config returns include and lib
	# directories from STAGING_DIR.
	# output/staging/usr/bin/llvm-config --includedir
	# output/staging/usr/include
	define HOST_LLVM_COPY_LLVM_CONFIG_TO_STAGING_DIR
	$(INSTALL) -D -m 0755 $(HOST_DIR)/bin/llvm-config \
	$(STAGING_DIR)/usr/bin/llvm-config
	endef
	HOST_LLVM_POST_INSTALL_HOOKS = HOST_LLVM_COPY_LLVM_CONFIG_TO_STAGING_DIR

	# By default llvm-tblgen is built and installed on the target but it is
	# not necessary. Also erase LLVMHello.so from /usr/lib
	define LLVM_DELETE_LLVM_TBLGEN_TARGET
	rm -f $(TARGET_DIR)/usr/bin/llvm-tblgen $(TARGET_DIR)/usr/lib/LLVMHello.so
	endef
	LLVM_POST_INSTALL_TARGET_HOOKS = LLVM_DELETE_LLVM_TBLGEN_TARGET

	$(eval $(cmake-package))
	$(eval $(host-cmake-package))