@@ -711,6 +711,26 @@ config BR2_REPRODUCIBLE
This is labeled as an experimental feature, as not all
packages behave properly to ensure reproducibility.
+config BR2_USER_HOST_CLANG_AS_CROSS_COMPILER
+ bool "Use Clang as cross-compiler (experimental)"
+ depends on BR2_PACKAGE_LLVM_ARCH_SUPPORTS
+ depends on BR2_HOST_GCC_AT_LEAST_4_8
+ depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
+ depends on BR2_TOOLCHAIN_HAS_THREADS
+ depends on BR2_INSTALL_LIBSTDCPP
+ depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 # std::shared_future
+ depends on !BR2_STATIC_LIBS
+ depends on BR2_USE_WCHAR # std::wstring
+ select BR2_PACKAGE_HOST_CLANG
+ help
+ This option will force Buildroot to use Clang as cross-compiler
+ instead of GCC. A GCC toolchain (internal or external) is still
+ needed to build with Clang.
+
+ This is labeled as an experimental feature, since we are
+ expecting some build and runtime issues for number of packages
+ (bootloaders, kernel).
+
endmenu
comment "Security Hardening Options"
@@ -200,9 +200,6 @@ endif
# Define TARGET_xx variables for all common binutils/gcc
TARGET_AR = $(TARGET_CROSS)ar
TARGET_AS = $(TARGET_CROSS)as
-TARGET_CC = $(TARGET_CROSS)gcc
-TARGET_CPP = $(TARGET_CROSS)cpp
-TARGET_CXX = $(TARGET_CROSS)g++
TARGET_FC = $(TARGET_CROSS)gfortran
TARGET_LD = $(TARGET_CROSS)ld
TARGET_NM = $(TARGET_CROSS)nm
@@ -211,6 +208,16 @@ TARGET_READELF = $(TARGET_CROSS)readelf
TARGET_OBJCOPY = $(TARGET_CROSS)objcopy
TARGET_OBJDUMP = $(TARGET_CROSS)objdump
+ifeq ($(BR2_USER_HOST_CLANG_AS_CROSS_COMPILER),y)
+TARGET_CC = $(HOST_DIR)/bin/clang
+TARGET_CPP = $(HOST_DIR)/bin/clang-cpp
+TARGET_CXX = $(HOST_DIR)/bin/clang++
+else
+TARGET_CC = $(TARGET_CROSS)gcc
+TARGET_CPP = $(TARGET_CROSS)cpp
+TARGET_CXX = $(TARGET_CROSS)g++
+endif
+
ifeq ($(BR2_STRIP_strip),y)
STRIP_STRIP_DEBUG := --strip-debug
TARGET_STRIP = $(TARGET_CROSS)strip
@@ -14,6 +14,11 @@ CLANG_LICENSE_FILES = LICENSE.TXT
CLANG_SUPPORTS_IN_SOURCE_BUILD = NO
CLANG_INSTALL_STAGING = YES
+# Allow host-clang to be build as part of the toolchain
+ifeq ($(BR2_USER_HOST_CLANG_AS_CROSS_COMPILER),y)
+HOST_CLANG_ADD_TOOLCHAIN_DEPENDENCY = NO
+endif
+
HOST_CLANG_DEPENDENCIES = host-llvm host-libxml2
CLANG_DEPENDENCIES = llvm host-clang
@@ -12,6 +12,13 @@ BR_LIBC = $(call qstrip,$(BR2_TOOLCHAIN_BUILDROOT_LIBC))
TOOLCHAIN_BUILDROOT_DEPENDENCIES = host-gcc-final
+# Make sure the clang cross-compiler is built before
+# generating Buildroot.cmake file from an
+# TOOLCHAIN_CMAKE_INSTALL_FILES hook.
+ifeq ($(BR2_USER_HOST_CLANG_AS_CROSS_COMPILER),y)
+TOOLCHAIN_BUILDROOT_DEPENDENCIES += host-clang
+endif
+
TOOLCHAIN_BUILDROOT_ADD_TOOLCHAIN_DEPENDENCY = NO
$(eval $(virtual-package))
@@ -15,6 +15,13 @@ ifeq ($(BR2_TOOLCHAIN_USES_MUSL),y)
TOOLCHAIN_EXTERNAL_DEPENDENCIES += musl-compat-headers
endif
+# Make sure the clang cross-compiler is built before
+# generating Buildroot.cmake file from an
+# TOOLCHAIN_CMAKE_INSTALL_FILES hook.
+ifeq ($(BR2_USER_HOST_CLANG_AS_CROSS_COMPILER),y)
+TOOLCHAIN_BUILDROOT_DEPENDENCIES += host-clang
+endif
+
$(eval $(virtual-package))
# Ensure the external-toolchain package has a prefix defined.
Add this new experimental option into "Advanced" menu since we are expecting some build and runtime issues for number of packages (bootloaders, kernel). Add host-clang as dependency in toolchain-buildroot and toolchain-external virtual in order to be sure that the clang cross-compiler is built before generating Buildroot.cmake file from an TOOLCHAIN_CMAKE_INSTALL_FILES hook (defined in cmake package). For toolchain-external package, we can latter remove the host-clang dependency if we can import Clang with the prebuilt external toolchain. Signed-off-by: Romain Naour <romain.naour@smile.fr> Cc: Matt Weber <matthew.weber@rockwellcollins.com> Cc: Valentin Korenblit <valentinkorenblit@gmail.com> --- Config.in | 20 +++++++++++++++++++ package/Makefile.in | 13 +++++++++--- package/clang/clang.mk | 5 +++++ .../toolchain-buildroot.mk | 7 +++++++ .../toolchain-external/toolchain-external.mk | 7 +++++++ 5 files changed, 49 insertions(+), 3 deletions(-)