cpp: Use malloc/free instead of kernel variants in new/delete

Use malloc/free instead of k_malloc/k_free in operator new/delete
implementation or use libstdc++ implementation when available.

Further updated cpp_synchronization sample to enable minimal libc heap
as virtual destructor requires operator delete which depends on free.

Signed-off-by: Jan Van Winkel <jan.van_winkel@dxplore.eu>

samples/cpp_synchronization/prj.conf

@@ -1 +1,2 @@
 CONFIG_CPLUSPLUS=y
+CONFIG_MINIMAL_LIBC_MALLOC_ARENA_SIZE=128

subsys/cpp/CMakeLists.txt

@@ -6,7 +6,9 @@ zephyr_sources(
   cpp_dtors.c
 )
 
-if (NOT CONFIG_LIB_CPLUSPLUS OR CONFIG_ZEPHYR_CPLUSPLUS)
+if (NOT CONFIG_LIB_CPLUSPLUS AND
+        (NOT CONFIG_MINIMAL_LIBC OR
+        (CONFIG_MINIMAL_LIBC_MALLOC_ARENA_SIZE GREATER 0)))
 zephyr_sources(
   cpp_virtual.c
   cpp_vtable.cpp

subsys/cpp/Kconfig

@@ -63,13 +63,6 @@ config RTTI
 	help
 	  This option enables support of C++ RTTI.
 
-
-config ZEPHYR_CPLUSPLUS
-	bool "Use Zephyr C++ Implementation"
-	help
-	  Use Zephyr implementation for operator new, delete, pure virtual
-	  functions and vtables.
-
 endif # LIB_CPLUSPLUS
 
 endif # ! MINIMAL_LIBC

subsys/cpp/cpp_new.cpp

@@ -4,115 +4,36 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#if defined(CONFIG_LIB_CPLUSPLUS)
+#include <stdlib.h>
-#include <new>
-#endif // CONFIG_LIB_CPLUSPLUS
-#include <kernel.h>
 
 void* operator new(size_t size)
 {
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
+	return malloc(size);
-	void* ptr = k_malloc(size);
-#if defined(__cpp_exceptions) && defined(CONFIG_LIB_CPLUSPLUS)
-	if (!ptr)
-		throw std::bad_alloc();
-#endif
-	return ptr;
-#else
-	ARG_UNUSED(size);
-	return NULL;
-#endif
 }
 
 void* operator new[](size_t size)
 {
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
+	return malloc(size);
-	void* ptr = k_malloc(size);
-#if defined(__cpp_exceptions) && defined(CONFIG_LIB_CPLUSPLUS)
-	if (!ptr)
-		throw std::bad_alloc();
-#endif
-	return ptr;
-#else
-	ARG_UNUSED(size);
-	return NULL;
-#endif
 }
 
 void operator delete(void* ptr) noexcept
 {
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
+	free(ptr);
-	k_free(ptr);
-#else
-	ARG_UNUSED(ptr);
-#endif
 }
 
 void operator delete[](void* ptr) noexcept
 {
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
+	free(ptr);
-	k_free(ptr);
-#else
-	ARG_UNUSED(ptr);
-#endif
 }
 
-#if defined(CONFIG_LIB_CPLUSPLUS)
-void* operator new(size_t size, const std::nothrow_t&) noexcept
-{
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
-	return k_malloc(size);
-#else
-	ARG_UNUSED(size);
-	return NULL;
-#endif
-}
-
-void* operator new[](size_t size, const std::nothrow_t&) noexcept
-{
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
-	return k_malloc(size);
-#else
-	ARG_UNUSED(size);
-	return NULL;
-#endif
-}
-
-void operator delete(void* ptr, const std::nothrow_t&) noexcept
-{
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
-	k_free(ptr);
-#else
-	ARG_UNUSED(ptr);
-#endif
-}
-
-void operator delete[](void* ptr, const std::nothrow_t&) noexcept
-{
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
-	k_free(ptr);
-#else
-	ARG_UNUSED(ptr);
-#endif
-}
-#endif // CONFIG_LIB_CPLUSPLUS
-
 #if (__cplusplus > 201103L)
 void operator delete(void* ptr, size_t) noexcept
 {
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
+	free(ptr);
-	k_free(ptr);
-#else
-	ARG_UNUSED(ptr);
-#endif
 }
 
 void operator delete[](void* ptr, size_t) noexcept
 {
-#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
+	free(ptr);
-	k_free(ptr);
-#else
-	ARG_UNUSED(ptr);
-#endif
 }
 #endif // __cplusplus > 201103L

subsys/cpp/cpp_vtable.cpp

@@ -14,8 +14,6 @@
  * @brief basic virtual tables required for classes to build
  *
  */
-#if !defined(CONFIG_LIB_CPLUSPLUS)
-
 namespace __cxxabiv1 {
 	class __class_type_info {
 		virtual void dummy();
@@ -26,4 +24,3 @@ namespace __cxxabiv1 {
 	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
 };
-#endif // !defined(CONFIG_LIB_CPLUSPLUS)

tests/application_development/libcxx/prj.conf

@@ -2,6 +2,5 @@ CONFIG_NEWLIB_LIBC=y
 CONFIG_CPLUSPLUS=y
 CONFIG_LIB_CPLUSPLUS=y
 CONFIG_STD_CPP17=y
-CONFIG_HEAP_MEM_POOL_SIZE=1024
 CONFIG_ZTEST=y
 CONFIG_ZTEST_STACKSIZE=2048

tests/application_development/libcxx/testcase.yaml

@@ -4,12 +4,6 @@ tests:
     platform_exclude: qemu_x86_coverage
     min_flash: 54
     tags: cpp
-  misc.app_dev.libcxx.zephyr_cpp:
-    arch_exclude: posix
-    platform_exclude: qemu_x86_coverage
-    tags: cpp
-    extra_configs:
-        - CONFIG_ZEPHYR_CPLUSPLUS=y
   misc.app_dev.libcxx.exceptions:
     arch_exclude: posix
     platform_exclude: qemu_x86_coverage