build: Add C++ support

Adds C++ support to the build system.

Change-Id: Ice1e57a13598e7a48b0bf3298fc318f4ce012ee6
Signed-off-by: Dmitriy Korovkin <[email protected]>
Signed-off-by: Peter Mitsis <[email protected]>

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/