[Backport v1.14-branch] C++: fix builds with non-Zephyr toolchain

CODEOWNERS

@@ -217,6 +217,7 @@ arch/arm/include/cortex_m/cmse.h          @ioannisg
 /lib/gui/                                 @vanwinkeljan
 /lib/os/                                  @andrewboie @andyross
 /lib/posix/                               @pfalcon
+/lib/libc/                                @nashif @andrewboie
 /kernel/device.c                          @andrewboie @andyross @nashif
 /kernel/idle.c                            @andrewboie @andyross @nashif
 /samples/basic/servo_motor/*microbit*     @jhe
@@ -276,6 +277,7 @@ arch/arm/include/cortex_m/cmse.h          @ioannisg
 /subsys/shell/                            @jarz-nordic @nordic-krch
 /subsys/storage/                          @nvlsianpu
 /subsys/usb/                              @jfischer-phytec-iot @finikorg
+/tests/application_development/libcxx/    @pabigot
 /tests/boards/native_posix/               @aescolar
 /tests/boards/intel_s1000_crb/            @rgundi @dcpleung @sathishkuttan
 /tests/bluetooth/                         @sjanc @jhedberg @Vudentz

lib/libc/newlib/CMakeLists.txt

@@ -3,18 +3,23 @@
 zephyr_library()
 zephyr_library_sources(libc-hooks.c)
 
+# Zephyr normally uses -ffreestanding, which with current GNU toolchains
+# means that the flag macros used by newlib 3.x <inttypes.h> to signal
+# support for PRI.64 macros are not present.  To make them available we
+# need to hook into the include path before the system files and
+# explicitly include the newlib header that provides those macros.
+zephyr_include_directories(include)
+
 # LIBC_*_DIR may or may not have been set by the toolchain. E.g. when
 # using ZEPHYR_TOOLCHAIN_VARIANT=cross-compile it will be either up to the
 # toolchain to know where it's libc implementation is, or if it is
 # unable to, it will be up to the user to specify LIBC_*_DIR vars to
-# point to a newlib implementation.
+# point to a newlib implementation.  Note that this does not change the
+# directory order if LIBC_INCLUDE_DIR is already a system header
+# directory.
 
-# We need to make sure this is included before the standard system
-# header include path's since we build with -ffreestanding and need
-# our libc headers to be picked instead of the toolchain's ffreestanding
-# headers.
 if(LIBC_INCLUDE_DIR)
-  zephyr_system_include_directories(${LIBC_INCLUDE_DIR})
+  zephyr_include_directories(${LIBC_INCLUDE_DIR})
 endif()
 
 if(LIBC_LIBRARY_DIR)

lib/libc/newlib/include/stdint.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2019 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_LIB_LIBC_NEWLIB_INCLUDE_STDINT_H_
+#define ZEPHYR_LIB_LIBC_NEWLIB_INCLUDE_STDINT_H_
+
+/* Work around -ffreestanding absence of defines required to support
+ * PRI.64 macros in <inttypes.h> by including the newlib header that
+ * provides the flag macros.
+ */
+
+#include <newlib.h>
+
+#ifdef __NEWLIB__
+/* Has this header.  Older versions do it in <stdint.h>. */
+#include <sys/_stdint.h>
+#endif /* __NEWLIB__ */
+
+/* This should work on GCC and clang.
+ *
+ * If we need to support a toolchain without #include_next the CMake
+ * infrastructure should be used to identify it and provide an
+ * alternative solution.
+ */
+#include_next <stdint.h>
+
+#endif /* ZEPHYR_LIB_LIBC_NEWLIB_INCLUDE_STDINT_H_ */

subsys/testsuite/ztest/include/ztest.h

@@ -20,10 +20,6 @@
 #ifndef __ZTEST_H__
 #define __ZTEST_H__
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * @defgroup ztest Zephyr testing suite
  */
@@ -44,19 +40,22 @@ extern "C" {
 /* FIXME: Properly integrate with Zephyr's arch specific code */
 #define CONFIG_X86 1
 #define CONFIG_PRINTK 1
-#endif
+#endif /* KERNEL */
 
 #include <misc/printk.h>
 #define PRINT printk
 
 #include <zephyr.h>
 
-
 #include <ztest_assert.h>
 #include <ztest_mock.h>
 #include <ztest_test.h>
 #include <tc_util.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void test_main(void);
 
 #ifdef __cplusplus

subsys/testsuite/ztest/include/ztest_assert.h

@@ -19,6 +19,10 @@
 #include <stdio.h>
 #include <string.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void ztest_test_fail(void);
 #if CONFIG_ZTEST_ASSERT_VERBOSE == 0
 
@@ -186,4 +190,8 @@ static inline void zassert_mem_equal(void *buf, void *exp, size_t size,
  * @}
  */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __ZTEST_ASSERT_H__ */

subsys/testsuite/ztest/include/ztest_mock.h

@@ -91,6 +91,10 @@
 
 #include <zephyr/types.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void z_init_mock(void);
 int z_cleanup_mock(void);
 
@@ -101,6 +105,10 @@ void z_ztest_check_expected_value(const char *fn, const char *param,
 void z_ztest_returns_value(const char *fn, uintptr_t value);
 uintptr_t z_ztest_get_return_value(const char *fn);
 
+#ifdef __cplusplus
+}
+#endif
+
 #else /* !CONFIG_ZTEST_MOCKING */
 
 #define z_init_mock()

subsys/testsuite/ztest/include/ztest_test.h

@@ -15,6 +15,10 @@
 
 #include <app_memory/app_memdomain.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct unit_test {
 	const char *name;
 	void (*test)(void);
@@ -170,4 +174,8 @@ extern struct k_mem_domain ztest_mem_domain;
  * @}
  */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __ZTEST_ASSERT_H__ */

tests/application_development/libcxx/CMakeLists.txt

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.13.1)
+include($ENV{ZEPHYR_BASE}/cmake/app/boilerplate.cmake NO_POLICY_SCOPE)
+project(cpp)
+
+FILE(GLOB app_sources src/*.cpp)
+target_sources(app PRIVATE ${app_sources})

tests/application_development/libcxx/prj.conf

@@ -0,0 +1,7 @@
+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/src/main.cpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2019 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <vector>
+#include <array>
+#include <functional>
+#include <ztest.h>
+
+BUILD_ASSERT(__cplusplus == 201703);
+
+std::array<int, 4> array = {1, 2, 3, 4};
+std::vector<int> vector;
+
+static void test_array(void)
+{
+	zassert_equal(array.size(), 4, "unexpected size");
+	zassert_equal(array[0], 1, "array[0] wrong");
+	zassert_equal(array[3], 4, "array[3] wrong");
+
+	std::array<u8_t, 2> local = {1, 2};
+	zassert_equal(local.size(), 2, "unexpected size");
+	zassert_equal(local[0], 1, "local[0] wrong");
+	zassert_equal(local[1], 2, "local[1] wrong");
+}
+
+static void test_vector(void)
+{
+	zassert_equal(vector.size(), 0, "vector init nonzero");
+	for (auto v : array) {
+		vector.push_back(v);
+	}
+	zassert_equal(vector.size(), array.size(), "vector store failed");
+}
+
+void test_main(void)
+{
+	TC_PRINT("version %u\n", (u32_t)__cplusplus);
+	ztest_test_suite(libcxx_tests,
+			 ztest_unit_test(test_array),
+			 ztest_unit_test(test_vector)
+		);
+
+	ztest_run_test_suite(libcxx_tests);
+}

tests/application_development/libcxx/testcase.yaml

@@ -0,0 +1,5 @@
+tests:
+  misc.app_dev.libcxx:
+    arch_exclude: posix
+    platform_exclude: qemu_x86_coverage qemu_x86_64
+    tags: cpp