Merge branch 'refactor/cxx_startup_function_cleanup' into 'master'

refactor(cxx): moved C++ init functions to cxx component

Closes IDF-8768

See merge request espressif/esp-idf!29095

components/cxx/CMakeLists.txt

@@ -6,8 +6,9 @@ endif()
 
 idf_component_register(SRCS "cxx_exception_stubs.cpp"
                             "cxx_guards.cpp"
+                            "cxx_init.cpp"
                         # Make sure that pthread is in component list
-                        PRIV_REQUIRES pthread)
+                        PRIV_REQUIRES pthread esp_system)
 
 if(NOT CONFIG_CXX_EXCEPTIONS)
     set(WRAP_FUNCTIONS
@@ -54,6 +55,7 @@ else()
     target_link_libraries(${COMPONENT_LIB} PUBLIC stdc++ gcc)
 endif()
 target_link_libraries(${COMPONENT_LIB} INTERFACE "-u __cxa_guard_dummy")
+target_link_libraries(${COMPONENT_LIB} INTERFACE "-u __cxx_init_dummy")
 
 # Force libpthread to appear later than libstdc++ in link line since libstdc++ depends on libpthread.
 # Furthermore, force libcxx to appear later than libgcc because some libgcc unwind code is wrapped, if C++

components/cxx/cxx_init.cpp

@@ -0,0 +1,50 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "sdkconfig.h"
+#include "esp_log.h"
+#include "esp_private/startup_internal.h"
+
+namespace {
+    const char *TAG = "C++ init";
+}
+
+#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
+// workaround for C++ exception large memory allocation
+extern "C" void _Unwind_SetEnableExceptionFdeSorting(unsigned char enable);
+
+ESP_SYSTEM_INIT_FN(init_cxx_exceptions, SECONDARY, BIT(0), 205)
+{
+    ESP_EARLY_LOGD(TAG, "Setting C++ exception workarounds.");
+    _Unwind_SetEnableExceptionFdeSorting(0);
+    return ESP_OK;
+}
+#endif // CONFIG_COMPILER_CXX_EXCEPTIONS
+
+/**
+ * This function overwrites the same function of libsupc++ (part of libstdc++).
+ * Consequently, libsupc++ will then follow our configured exception emergency pool size.
+ *
+ * It will be called even with -fno-exception for user code since the stdlib still uses exceptions.
+ */
+extern "C" size_t __cxx_eh_arena_size_get(void)
+{
+#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
+    ESP_EARLY_LOGD(TAG, "Setting C++ exception emergency pool to %u.", CONFIG_COMPILER_CXX_EXCEPTIONS_EMG_POOL_SIZE);
+    return CONFIG_COMPILER_CXX_EXCEPTIONS_EMG_POOL_SIZE;
+#else
+    ESP_EARLY_LOGD(TAG, "Setting C++ exception emergency pool to 0.");
+    return 0;
+#endif
+}
+
+/**
+ * Dummy function used to force linking this file.
+ * This works via -u __cxx_init_dummy flag in CMakeLists.txt
+ */
+extern "C" void __cxx_init_dummy(void)
+{
+}

components/esp_system/startup_funcs.c

@@ -167,41 +167,6 @@ ESP_SYSTEM_INIT_FN(init_coexist, SECONDARY, BIT(0), 204)
 }
 #endif // CONFIG_SW_COEXIST_ENABLE || CONFIG_EXTERNAL_COEX_ENABLE
 
-#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
-/**
- * This function overwrites a the same function of libsupc++ (part of libstdc++).
- * Consequently, libsupc++ will then follow our configured exception emergency pool size.
- *
- * It will be called even with -fno-exception for user code since the stdlib still uses exceptions.
- */
-size_t __cxx_eh_arena_size_get(void)
-{
-#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
-    return CONFIG_COMPILER_CXX_EXCEPTIONS_EMG_POOL_SIZE;
-#else
-    return 0;
-#endif
-}
-
-// workaround for C++ exception crashes
-void _Unwind_SetNoFunctionContextInstall(unsigned char enable) __attribute__((weak, alias("_Unwind_SetNoFunctionContextInstall_Default")));
-// workaround for C++ exception large memory allocation
-void _Unwind_SetEnableExceptionFdeSorting(unsigned char enable);
-
-static IRAM_ATTR void _Unwind_SetNoFunctionContextInstall_Default(unsigned char enable __attribute__((unused)))
-{
-    (void)0;
-}
-
-ESP_SYSTEM_INIT_FN(init_cxx_exceptions, SECONDARY, BIT(0), 205)
-{
-    ESP_EARLY_LOGD(TAG, "Setting C++ exception workarounds.");
-    _Unwind_SetNoFunctionContextInstall(1);
-    _Unwind_SetEnableExceptionFdeSorting(0);
-    return ESP_OK;
-}
-#endif // CONFIG_COMPILER_CXX_EXCEPTIONS
-
 #ifndef CONFIG_BOOTLOADER_WDT_DISABLE_IN_USER_CODE
 ESP_SYSTEM_INIT_FN(init_disable_rtc_wdt, SECONDARY, BIT(0), 999)
 {

components/esp_system/system_init_fn.txt

@@ -87,7 +87,7 @@ SECONDARY: 140: init_dbg_stubs in components/app_trace/debug_stubs.c on BIT(0)
 SECONDARY: 201: init_pm in components/esp_system/startup_funcs.c on BIT(0)
 SECONDARY: 203: init_apb_dma in components/esp_system/startup_funcs.c on BIT(0)
 SECONDARY: 204: init_coexist in components/esp_system/startup_funcs.c on BIT(0)
-SECONDARY: 205: init_cxx_exceptions in components/esp_system/startup_funcs.c on BIT(0)
+SECONDARY: 205: init_cxx_exceptions in components/cxx/cxx_init.cpp on BIT(0)
 
 # usb_console needs to create an esp_timer at startup.
 # This can be done only after esp_timer initialization (esp_timer_init_os).