ARC: MWDT: add C++ support

cmake/compiler/arcmwdt/compiler_flags.cmake

@@ -115,20 +115,19 @@ set_compiler_property(PROPERTY warning_error_misra_sane -Werror=vla)
 
 set_compiler_property(PROPERTY cstd -std=)
 
-if (NOT CONFIG_NEWLIB_LIBC AND
-    NOT CONFIG_NATIVE_APPLICATION)
+if (NOT CONFIG_ARCMWDT_LIBC)
   set_compiler_property(PROPERTY nostdinc -Hno_default_include -Hnoarcexlib)
-  set_compiler_property(APPEND PROPERTY nostdinc_include ${NOSTDINC})
 endif()
 
+set_compiler_property(APPEND PROPERTY nostdinc_include ${NOSTDINC})
 
 # C++ std options
 set_property(TARGET compiler-cpp PROPERTY dialect_cpp98 "-std=c++98")
 set_property(TARGET compiler-cpp PROPERTY dialect_cpp11 "-std=c++11")
+set_property(TARGET compiler-cpp PROPERTY dialect_cpp14 "-std=c++14")
+set_property(TARGET compiler-cpp PROPERTY dialect_cpp17 "-std=c++17")
 
-#no support of C++14, C++17, C++2a, C++20, C++2b
-set_property(TARGET compiler-cpp PROPERTY dialect_cpp14 "")
-set_property(TARGET compiler-cpp PROPERTY dialect_cpp17 "")
+#no support of C++2a, C++20, C++2b
 set_property(TARGET compiler-cpp PROPERTY dialect_cpp2a "")
 set_property(TARGET compiler-cpp PROPERTY dialect_cpp20 "")
 set_property(TARGET compiler-cpp PROPERTY dialect_cpp2b "")
@@ -173,7 +172,7 @@ set_compiler_property(PROPERTY security_canaries -fstack-protector-all)
 set_compiler_property(PROPERTY security_fortify "")
 
 # Required C++ flags when using mwdt
-set_property(TARGET compiler-cpp PROPERTY required "")
+set_property(TARGET compiler-cpp PROPERTY required "-Hcplus" "-Hoff=Stackcheck_alloca")
 
 # Compiler flag for turning off thread-safe initialization of local statics
 set_property(TARGET compiler-cpp PROPERTY no_threadsafe_statics "-fno-threadsafe-statics")

cmake/compiler/arcmwdt/target.cmake

@@ -26,6 +26,10 @@ set(NOSTDINC "")
 
 list(APPEND NOSTDINC ${TOOLCHAIN_HOME}/arc/inc)
 
+if(CONFIG_ARCMWDT_LIBC AND CONFIG_LIB_CPLUSPLUS)
+  list(APPEND NOSTDINC ${TOOLCHAIN_HOME}/arc/lib/src/c++/inc)
+endif()
+
 # For CMake to be able to test if a compiler flag is supported by the
 # toolchain we need to give CMake the necessary flags to compile and
 # link a dummy C file.

cmake/linker/arcmwdt/target.cmake

@@ -196,7 +196,7 @@ endmacro()
 # link C++ libraries
 macro(toolchain_ld_cpp)
   zephyr_link_libraries(
-    -Hcppmw -Hcplus
+    -Hcplus
   )
 endmacro()
 

include/arch/arc/v2/linker.ld

@@ -224,6 +224,16 @@ SECTIONS {
 	__kernel_ram_end = .;
 	__kernel_ram_size = __kernel_ram_end - __kernel_ram_start;
 
+#ifdef __MWDT_LINKER_CMD__
+/* mwdt requires _fstack, _estack which will be used in _stkchk.
+ * _stkchk is inserted by mwdt automatically, if _fstack, _estack is not
+ * set correctly, the  brk_s instruction will be called
+ * here, we use a trick to deceive the compiler.
+ */
+	_fstack = _image_ram_start;
+	_estack = .;
+#endif /* __MWDT_LINKER_CMD__ */
+
 	GROUP_END(RAMABLE_REGION)
 
 /* Located in generated directory. This file is populated by the

include/toolchain/mwdt.h

@@ -71,6 +71,14 @@
 #endif
 #endif /* _SSIZE_T_DEFINED */
 
+#ifdef CONFIG_NEWLIB_LIBC
+  #error "ARC MWDT doesn't support building with CONFIG_NEWLIB_LIBC as it doesn't have newlib"
+#endif /* CONFIG_NEWLIB_LIBC */
+
+#ifdef CONFIG_NATIVE_APPLICATION
+  #error "ARC MWDT doesn't support building Zephyr as an native application"
+#endif /* CONFIG_NATIVE_APPLICATION */
+
 
 #define __no_optimization __attribute__((optnone))
 

tests/subsys/cpp/libcxx/prj.conf

@@ -1,4 +1,3 @@
-CONFIG_NEWLIB_LIBC=y
 CONFIG_CPLUSPLUS=y
 CONFIG_LIB_CPLUSPLUS=y
 CONFIG_STD_CPP17=y

tests/subsys/cpp/libcxx/testcase.yaml

@@ -1,19 +1,29 @@
 common:
-  filter: TOOLCHAIN_HAS_NEWLIB == 1
   integration_platforms:
     - mps2_an385
 tests:
   cpp.libcxx.newlib:
+    filter: TOOLCHAIN_HAS_NEWLIB == 1
     toolchain_exclude: xcc
     min_flash: 54
     tags: cpp
     extra_configs:
+        - CONFIG_NEWLIB_LIBC=y
         - CONFIG_NEWLIB_LIBC_NANO=n
         - CONFIG_EXCEPTIONS=y
   cpp.libcxx.newlib_nano:
+    filter: TOOLCHAIN_HAS_NEWLIB == 1
     toolchain_exclude: xcc
     min_flash: 54
     tags: cpp
     timeout: 30
     extra_configs:
+        - CONFIG_NEWLIB_LIBC=y
         - CONFIG_NEWLIB_LIBC_NANO=y
+  cpp.libcxx.arcmwdtlib:
+    toolchain_allow: arcmwdt
+    platform_allow: nsim_hs nsim_em
+    min_flash: 54
+    tags: cpp
+    extra_configs:
+        - CONFIG_ARCMWDT_LIBC=y