build: Add C++ support

Adds C++ support to the build system.

Change-Id: Ice1e57a13598e7a48b0bf3298fc318f4ce012ee6
Signed-off-by: Dmitriy Korovkin <dmitriy.korovkin@windriver.com>
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>

Makefile

@@ -300,8 +300,10 @@ AS		= $(CROSS_COMPILE)as
 LD		= $(CROSS_COMPILE)ld
 ifeq ($(USE_CCACHE),1)
 CC		= $(CCACHE) $(CROSS_COMPILE)gcc
+CXX		= $(CCACHE) $(CROSS_COMPILE)g++
 else
 CC		= $(CROSS_COMPILE)gcc
+CXX		= $(CROSS_COMPILE)g++
 endif
 CPP		= $(CC) -E
 AR		= $(CROSS_COMPILE)ar
@@ -366,6 +368,18 @@ KBUILD_CFLAGS   := -c -g -std=c99 \
 		-Wno-format-zero-length \
 		-Wno-main -ffreestanding
 
+KBUILD_CXXFLAGS   := -c -g -std=c++11 \
+		-fno-reorder-functions \
+		-fno-asynchronous-unwind-tables \
+		-fno-omit-frame-pointer \
+		-fcheck-new \
+		-fno-defer-pop -Wall \
+		-Wno-unused-but-set-variable \
+		-Wno-format-zero-length \
+		-Wno-main -ffreestanding \
+		-ffunction-sections -fdata-sections \
+		-fno-rtti -fno-exceptions
+
 KBUILD_AFLAGS   := -c -g -xassembler-with-cpp
 
 LDFLAGS += $(call ld-option,-nostartfiles)
@@ -377,13 +391,13 @@ KERNELVERSION = $(VERSION_MAJOR)$(if $(VERSION_MINOR),.$(VERSION_MINOR)$(if $(PA
 
 export VERSION_MAJOR VERSION_MINOR PATCHLEVEL VERSION_RESERVED EXTRAVERSION
 export KERNELRELEASE KERNELVERSION
-export ARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
+export ARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC CXX
 export CPP AR NM STRIP OBJCOPY OBJDUMP
 export MAKE AWK INSTALLKERNEL PERL PYTHON GENIDT GENOFFSET_H
 export HOSTCXX HOSTCXXFLAGS CHECK CHECKFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS ZEPHYRINCLUDE OBJCOPYFLAGS LDFLAGS
-export KBUILD_CFLAGS CFLAGS_GCOV KBUILD_AFLAGS AFLAGS_KERNEL
+export KBUILD_CFLAGS KBUILD_CXXFLAGS CFLAGS_GCOV KBUILD_AFLAGS AFLAGS_KERNEL
 export KBUILD_ARFLAGS
 
 
@@ -599,6 +613,7 @@ export LDFLAG_LINKERCMD
 include arch/$(ARCH)/Makefile
 
 KBUILD_CFLAGS += $(CFLAGS)
+KBUILD_CXXFLAGS += $(CXXFLAGS)
 KBUILD_AFLAGS += $(CFLAGS)
 
 
@@ -1103,6 +1118,10 @@ qemu: zephyr
 	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
 %.o: %.c prepare scripts FORCE
 	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
+%.o: %.cpp prepare scripts FORCE
+	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
+%.o: %.cxx prepare scripts FORCE
+	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
 %.lst: %.c prepare scripts FORCE
 	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
 %.s: %.S prepare scripts FORCE

arch/arc/Makefile

@@ -4,4 +4,5 @@ arch-$(CONFIG_CPU_ARCEM4) = $(call cc-option,-mARCv2EM) \
                          $(call cc-option,-mav2em,) $(call cc-option,-mno-sdata)
 
 KBUILD_CFLAGS += $(arch-y) $(cflags-y)
+KBUILD_CXXFLAGS += $(arch-y) $(cflags-y)
 KBUILD_AFLAGS += $(arch-y)

arch/arm/Makefile

@@ -8,6 +8,7 @@ arch-$(CONFIG_CPU_CORTEX_M4) += $(call cc-option,-mthumb -mcpu=cortex-m4) \
 cflags-$(CONFIG_LTO) = $(call cc-option,-flto,)
 
 KBUILD_CFLAGS += $(cflags-y) $(arch-y)
+KBUILD_CXXFLAGS += $(cflags-y) $(arch-y)
 KBUILD_AFLAGS += $(arch-y)
 
 QEMU_CPU_TYPE_arm = cortex-m3

arch/arm/core/Makefile

@@ -10,6 +10,7 @@ obj-y = atomic.o exc_exit.o irq_init.o \
 	fault_s.o gdb_stub.o isr_wrapper.o \
 	fatal.o sys_fatal_error_handler.o
 
+obj-$(CONFIG_CPLUSPLUS) += __aeabi_atexit.o
 obj-$(CONFIG_MICROKERNEL) += task_abort.o
 obj-$(CONFIG_IRQ_OFFLOAD) += irq_offload.o
 obj-$(CONFIG_CPU_CORTEX_M) += cortex_m/

arch/arm/core/__aeabi_atexit.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2016 Wind River Systems, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * @file
+ * @brief Basic C++ destructor module for globals for ARM
+ */
+
+#include <toolchain.h>
+
+EXTERN_C int __cxa_atexit(void (*destructor)(void *), void *objptr, void *dso);
+
+/**
+ * @brief Register destructor for a global object
+ *
+ * @param objptr global object pointer
+ * @param destructor the global object destructor function
+ * @param dso Dynamic Shared Object handle for shared libraries
+ *
+ * Wrapper for __cxa_atexit()
+ */
+int __aeabi_atexit(void *objptr, void (*destructor)(void *), void *dso)
+{
+	return __cxa_atexit(destructor, objptr, dso);
+}

arch/x86/Makefile

@@ -25,6 +25,7 @@ arch-$(CONFIG_CPU_ATOM) += $(call cc-option,-march=atom) \
 arch-$(CONFIG_CPU_MINUTEIA) += $(call cc-option,-march=pentium)
 
 KBUILD_CFLAGS += $(cflags-y) $(arch-y)
+KBUILD_CXXFLAGS += $(cflags-y) $(arch-y)
 KBUILD_AFLAGS += $(arch-y)
 
 QEMU_BIOS ?= /usr/share/qemu

include/arch/arc/v2/linker.cmd

@@ -86,6 +86,7 @@ SECTIONS {
 
 		*(.text)
 		*(".text.*")
+		*(.gnu.linkonce.t.*)
 
 		_image_text_end = .;
 	} GROUP_LINK_IN(ROMABLE_REGION)
@@ -98,6 +99,7 @@ SECTIONS {
 		__devconfig_end = .;
 	} GROUP_LINK_IN(ROMABLE_REGION)
 
+#ifdef CONFIG_CPLUSPLUS
 	SECTION_PROLOGUE(_CTOR_SECTION_NAME,,) {
 		/*
 		 * The compiler fills the constructor pointers table below, hence
@@ -114,9 +116,19 @@ SECTIONS {
 		__CTOR_END__ = .;
 	} GROUP_LINK_IN(ROMABLE_REGION)
 
+	SECTION_PROLOGUE(init_array, (OPTIONAL),)
+	{
+		. = ALIGN(4);
+		__init_array_start = .;
+		KEEP(*(SORT_BY_NAME(".init_array*")))
+		__init_array_end = .;
+	} GROUP_LINK_IN(ROMABLE_REGION)
+#endif
+
 	SECTION_PROLOGUE(_RODATA_SECTION_NAME,,) {
 		*(.rodata)
 		*(".rodata.*")
+		*(.gnu.linkonce.r.*)
 	} GROUP_LINK_IN(ROMABLE_REGION)
 
 	_image_rom_end = .;

include/arch/arm/cortex_m/scripts/linker.cmd

@@ -101,6 +101,7 @@ SECTIONS
 	_image_text_start = .;
 	*(.text)
 	*(".text.*")
+	*(.gnu.linkonce.t.*)
 	} GROUP_LINK_IN(ROMABLE_REGION)
 
 	_image_text_end = .;
@@ -128,10 +129,38 @@ SECTIONS
 	__exidx_end = .;
 	} GROUP_LINK_IN(ROMABLE_REGION)
 
+#ifdef CONFIG_CPLUSPLUS
+	SECTION_PROLOGUE(_CTOR_SECTION_NAME,,)
+	{
+	/*
+	 * The compiler fills the constructor pointers table below, hence symbol
+	 * __CTOR_LIST__ must be aligned on 4 byte boundary.
+	 * To align with the C++ standard, the first elment of the array
+	 * contains the number of actual constructors. The last element is
+	 * NULL.
+	 */
+	. = ALIGN(4);
+	__CTOR_LIST__ = .;
+	LONG((__CTOR_END__ - __CTOR_LIST__) / 4 - 2)
+	KEEP(*(SORT_BY_NAME(".ctors*")))
+	LONG(0)
+	__CTOR_END__ = .;
+	} GROUP_LINK_IN(ROMABLE_REGION)
+
+    SECTION_PROLOGUE(init_array, (OPTIONAL),)
+	{
+	. = ALIGN(4);
+	__init_array_start = .;
+	KEEP(*(SORT_BY_NAME(".init_array*")))
+	__init_array_end = .;
+	} GROUP_LINK_IN(ROMABLE_REGION)
+#endif
+
     SECTION_PROLOGUE(_RODATA_SECTION_NAME,,)
 	{
 	*(.rodata)
 	*(".rodata.*")
+	*(.gnu.linkonce.r.*)
 	} GROUP_LINK_IN(ROMABLE_REGION)
 
 	_image_rom_end = .;

include/arch/x86/linker-common-sections.h

@@ -74,6 +74,7 @@ SECTIONS
 	*(".text_start.*")
 	*(.text)
 	*(".text.*")
+	*(.gnu.linkonce.t.*)
 	*(.eh_frame)
 	*(.init)
 	*(.fini)
@@ -83,6 +84,33 @@ SECTIONS
 
 	_image_text_end = .;
 
+#ifdef CONFIG_CPLUSPLUS
+	SECTION_PROLOGUE(_CTOR_SECTION_NAME, ,)
+	{
+	/*
+	 * The compiler fills the constructor pointers table below, hence symbol
+	 * __CTOR_LIST__ must be aligned on 4 byte boundary.
+	 * To align with the C++ standard, the first elment of the array
+	 * contains the number of actual constructors. The last element is
+	 * NULL.
+	 */
+	. = ALIGN(4);
+	__CTOR_LIST__ = .;
+	LONG((__CTOR_END__ - __CTOR_LIST__) / 4 - 2)
+	KEEP(*(SORT_BY_NAME(".ctors*")))
+	LONG(0)
+	__CTOR_END__ = .;
+	} GROUP_LINK_IN(ROMABLE_REGION)
+
+	SECTION_PROLOGUE(init_array, (OPTIONAL),)
+	{
+	. = ALIGN(4);
+	__init_array_start = .;
+	KEEP(*(SORT_BY_NAME(".init_array*")))
+	__init_array_end = .;
+	} GROUP_LINK_IN(ROMABLE_REGION)
+#endif
+
 	SECTION_PROLOGUE(devconfig, (OPTIONAL),)
 	{
 		__devconfig_start = .;
@@ -95,6 +123,7 @@ SECTIONS
 	{
 	*(.rodata)
 	*(".rodata.*")
+	*(.gnu.linkonce.r.*)
 #if ALL_DYN_STUBS == 0
 	IDT_MEMORY
 #endif

include/nanokernel.h

@@ -1363,6 +1363,35 @@ struct nano_timer *_track_list_nano_timer;
 }
 #endif
 
+#if defined(CONFIG_CPLUSPLUS) && defined(__cplusplus)
+/*
+ * Define new and delete operators.
+ * At this moment they do nothing since objects are supposed
+ * to be statically allocated
+ */
+inline void operator delete(void *ptr)
+{
+	(void)ptr;
+}
+
+inline void operator delete[](void *ptr)
+{
+	(void)ptr;
+}
+
+inline void *operator new(size_t size)
+{
+	(void)size;
+	return NULL;
+}
+
+inline void *operator new[](size_t size)
+{
+	(void)size;
+	return NULL;
+}
+#endif
+
 /* architecture-specific nanokernel public APIs */
 
 #include <arch/cpu.h>

kernel/microkernel/k_init.c

@@ -96,6 +96,14 @@ void _main(void)
 	_sys_device_do_config_level(_SYS_INIT_LEVEL_MICROKERNEL);
 	_sys_device_do_config_level(_SYS_INIT_LEVEL_APPLICATION);
 
+#ifdef CONFIG_CPLUSPLUS
+	/* Process the .ctors and .init_array sections */
+	extern void __do_global_ctors_aux(void);
+	extern void __do_init_array_aux(void);
+	__do_global_ctors_aux();
+	__do_init_array_aux();
+#endif
+
 
 #ifdef CONFIG_WORKLOAD_MONITOR
 	_k_workload_monitor_calibrate();

kernel/nanokernel/nano_init.c

@@ -105,6 +105,14 @@ static void _main(void)
 	_sys_device_do_config_level(_SYS_INIT_LEVEL_NANOKERNEL);
 	_sys_device_do_config_level(_SYS_INIT_LEVEL_APPLICATION);
 
+#ifdef CONFIG_CPLUSPLUS
+	/* Process the .ctors and .init_array sections */
+	extern void __do_global_ctors_aux(void);
+	extern void __do_init_array_aux(void);
+	__do_global_ctors_aux();
+	__do_init_array_aux();
+#endif
+
 	extern void main(void);
 	main();
 }

misc/Kconfig

@@ -93,6 +93,12 @@ config TOOLCHAIN_VARIANT
 	For optimized compilers with reduced features, specify the name
 	of the variant.
 
+config CPLUSPLUS
+	bool "Enable C++ support for the application"
+	default n
+	help
+	This option enables the use of applications built with C++.
+
 choice
 prompt "C Library"
 default MINIMAL_LIBC

misc/Makefile

@@ -1,4 +1,6 @@
 obj-y =
+obj-$(CONFIG_CPLUSPLUS) += cpp_virtual.o cpp_vtable.o               \
+                           cpp_init_array.o cpp_ctors.o cpp_dtors.o
 obj-$(CONFIG_PRINTK) += printk.o
 obj-$(CONFIG_REBOOT) += reboot.o
 obj-y += generated/

misc/cpp_ctors.c

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2012-2014 Wind River Systems, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @file - Constructor module
+ * @brief
+ * The ctors section contains a list of function pointers that execute the
+ * C++ constructors of static global objects. These must be executed before
+ * the application's main() routine.
+ *
+ * NOTE: Not all compilers put those function pointers into the ctors section;
+ * some put them into the init_array section instead.
+ */
+
+/* What a constructor function pointer looks like */
+
+typedef void (*CtorFuncPtr)(void);
+
+/* Constructor function pointer list is generated by the linker script. */
+
+extern CtorFuncPtr __CTOR_LIST__[];
+extern CtorFuncPtr __CTOR_END__[];
+
+/**
+ *
+ * @brief Invoke all C++ style global object constructors
+ *
+ * This routine is invoked by the kernel prior to the execution of the
+ * application's main().
+ */
+void __do_global_ctors_aux(void)
+{
+	unsigned int nCtors;
+
+	nCtors = (unsigned int)__CTOR_LIST__[0];
+
+	while (nCtors >= 1) {
+		__CTOR_LIST__[nCtors--]();
+	}
+}

misc/cpp_dtors.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2016 Wind River Systems, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * @file
+ * @brief Basic C++ destructor module for globals
+ *
+ */
+
+#include <toolchain.h>
+
+void *__dso_handle = 0;
+
+/**
+ * @brief Register destructor for a global object
+ *
+ * @param destructor the global object destructor function
+ * @param objptr global object pointer
+ * @param dso Dynamic Shared Object handle for shared libraries
+ *
+ * Function does nothing at the moment, assuming the global objects
+ * do not need to be deleted
+ *
+ * @return N/A
+ */
+int __cxa_atexit(void (*destructor)(void *), void *objptr, void *dso)
+{
+	ARG_UNUSED(destructor);
+	ARG_UNUSED(objptr);
+	ARG_UNUSED(dso);
+	return 0;
+}

misc/cpp_init_array.c

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2015 Wind River Systems, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * @file
+ * @brief Execute initialization routines referenced in .init_array section
+ */
+
+typedef void (*func_ptr)(void);
+
+extern func_ptr __init_array_start[0];
+extern func_ptr __init_array_end[0];
+
+/**
+ * @brief Execute initialization routines referenced in .init_array section
+ *
+ * @return N/A
+ */
+void __do_init_array_aux(void)
+{
+	for (func_ptr *func = __init_array_start;
+		func < __init_array_end;
+		func++) {
+		(*func)();
+	}
+}

misc/cpp_virtual.c

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2015 Wind River Systems, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * @file
+ * @brief Stub for C++ pure virtual functions
+ */
+
+/**
+ * @brief Stub for pure virtual functions
+ *
+ * This routine is needed for linking C++ code that uses pure virtual
+ * functions.
+ *
+ * @return N/A
+ */
+void __cxa_pure_virtual(void)
+{
+	while (1) {
+		;
+	}
+}

misc/cpp_vtable.cpp

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2015 Wind River Systems, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * @file
+ * @brief Stub for C++ virtual tables
+ */
+
+/**
+ *
+ * @brief basic virtual tables required for classes to build
+ *
+ */
+
+namespace __cxxabiv1 {
+	class __class_type_info {
+		virtual void dummy();
+	};
+	class __si_class_type_info {
+		virtual void dummy();
+	};
+	void __class_type_info::dummy() { }  // causes the vtable to get created here
+	void __si_class_type_info::dummy() { }  // causes the vtable to get created here
+};

scripts/Makefile.build

@@ -20,6 +20,7 @@ subdir-y :=
 subdir-m :=
 EXTRA_AFLAGS   :=
 EXTRA_CFLAGS   :=
+EXTRA_CXXFLAGS :=
 EXTRA_CPPFLAGS :=
 EXTRA_LDFLAGS  :=
 asflags-y  :=
@@ -196,6 +197,47 @@ quiet_cmd_cc_lst_c = MKLST   $@
 $(obj)/%.lst: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_lst_c)
 
+# C++ (.cpp and .cxx) files
+# The C++ file is compiled and updated dependency information is generated.
+# (See cmd_cc_o_cxx + relevant part of rule_cc_o_cxx)
+
+# No support for module versioning for C++ (for now)
+quiet_cmd_cc_o_cxx = C++ $(quiet_modtag) $@
+cmd_cc_o_cxx = $(CXX) $(cxx_flags) -c -o $@ $<
+
+define rule_cc_o_cxx
+	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
+$(call echo-cmd,cc_o_cxx) $(cmd_cc_o_cxx);				  \
+	$(cmd_modversions)						  \
+	$(call echo-cmd,record_mcount)					  \
+	$(cmd_record_mcount)						  \
+	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_cxx)' >    \
+	                                              $(dot-target).tmp;  \
+	rm -f $(depfile);						  \
+	mv -f $(dot-target).tmp $(dot-target).cmd
+endef
+
+# Built-in and composite module parts
+$(obj)/%.o: $(src)/%.cpp $(recordmcount_source) FORCE
+	$(call cmd,force_checksrc)
+	$(call if_changed_rule,cc_o_cxx)
+
+$(obj)/%.o: $(src)/%.cxx $(recordmcount_source) FORCE
+	$(call cmd,force_checksrc)
+	$(call if_changed_rule,cc_o_cxx)
+
+quiet_cmd_cc_lst_cxx = MKLST   $@
+      cmd_cc_lst_cxx = $(CXX) $(cxx_flags) -g -c -o $*.o $< && \
+		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
+				     System.map $(OBJDUMP) > $@
+
+$(obj)/%.lst: $(src)/%.cxx FORCE
+	$(call if_changed_dep,cc_lst_cxx)
+
+$(obj)/%.lst: $(src)/%.cpp FORCE
+	$(call if_changed_dep,cc_lst_cxx)
+
+
 # Compile assembler sources (.S)
 # ---------------------------------------------------------------------------
 

scripts/Makefile.lib

@@ -3,6 +3,7 @@
 asflags-y  += $(EXTRA_AFLAGS)
 ccflags-y  += $(EXTRA_CFLAGS)
 cppflags-y += $(EXTRA_CPPFLAGS)
+cxxflags-y += $(EXTRA_CXXFLAGS)
 ldflags-y  += $(EXTRA_LDFLAGS)
 
 #
@@ -114,6 +115,9 @@ _c_flags       = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
 _a_flags       = $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(KBUILD_SUBDIR_ASFLAGS) \
                  $(asflags-y) $(AFLAGS_$(basetarget).o)
 _cpp_flags     = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))
+orig_cxx_flags = $(KBUILD_CPPFLAGS) $(KBUILD_CXXFLAGS) $(KBUILD_SUBDIR_CXXFLAGS) \
+                 $(cxxflags-y) $(CXXFLAGS_$(basetarget).o)
+_cxx_flags     = $(filter-out $(CXXFLAGS_REMOVE_$(basetarget).o), $(orig_cxx_flags))
 
 # If building the kernel in a separate objtree expand all occurrences
 # of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').
@@ -122,6 +126,7 @@ ifeq ($(KBUILD_SRC),)
 __c_flags	= $(_c_flags)
 __a_flags	= $(_a_flags)
 __cpp_flags     = $(_cpp_flags)
+__cxx_flags     = $(_cxx_flags)
 else
 
 # -I$(obj) locates generated .h files
@@ -131,6 +136,7 @@ else
 __c_flags	= $(call addtree,-I$(obj)) $(call flags,_c_flags)
 __a_flags	=                          $(call flags,_a_flags)
 __cpp_flags     =                          $(call flags,_cpp_flags)
+__cxx_flags     =                          $(call flags,_cxx_flags)
 endif
 
 c_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(ZEPHYRINCLUDE)     \
@@ -149,6 +155,10 @@ dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 -I$(srctree)/drivers/of/testcase-data                   \
 		 -undef -D__DTS__
 
+cxx_flags      = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(ZEPHYRINCLUDE)     \
+		 $(__cxx_flags) $(modkern_cflags)                           \
+		 -D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)
+
 # Finds the multi-part object the current object will be linked into
 modname-multi = $(sort $(foreach m,$(multi-used),\
 		$(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))

scripts/sysgen

@@ -320,7 +320,7 @@ def kernel_main_c_tasks():
 
     kernel_main_c_out("\n")
     for task in task_list:
-        kernel_main_c_out("extern void %s(void);\n" % task[2])
+        kernel_main_c_out("EXTERN_C void %s(void);\n" % task[2])
 
     # task descriptors (including one for idle task)
     #