toolchain: C++ exception workaround

* disable C++ exception FDE sorting (saves RAM)

Closes IDF-1128

components/cxx/test/test_cxx.cpp

@@ -44,16 +44,23 @@ TEST_CASE("can use std::vector", "[cxx]")
     TEST_ASSERT_EQUAL(51, std::accumulate(std::begin(v), std::end(v), 0));
 }
 
-/* Note: When first exception (in system) is thrown this test produces memory leaks report (~500 bytes):
-   - 392 bytes (can vary) as libunwind allocates memory to keep stack frames info to handle exceptions.
-     This info is kept until global destructors are called by __do_global_dtors_aux()
+/* Note: When first exception (in system) is thrown this test produces memory leaks report (~300 bytes):
    - 8 bytes are allocated by __cxa_get_globals() to keep __cxa_eh_globals
    - 16 bytes are allocated by pthread_setspecific() which is called by __cxa_get_globals() to init TLS var for __cxa_eh_globals
    - 88 bytes are allocated by pthread_setspecific() to init internal lock
+   - some more memory...
    */
 #ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
 
-TEST_CASE("c++ exceptions work", "[cxx] [exceptions] [leaks=816]")
+#if CONFIG_IDF_TARGET_ESP32
+#define LEAKS "300"
+#elif CONFIG_IDF_TARGET_ESP32S2
+#define LEAKS "800"
+#else
+#error "unknown target in CXX tests, can't set leaks threshold"
+#endif
+
+TEST_CASE("c++ exceptions work", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     int thrown_value;
     try {
@@ -65,7 +72,7 @@ TEST_CASE("c++ exceptions work", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ bool exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ bool exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     bool thrown_value = false;
     try {
@@ -77,7 +84,7 @@ TEST_CASE("c++ bool exception", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ void exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ void exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     void* thrown_value = 0;
     try {
@@ -89,7 +96,7 @@ TEST_CASE("c++ void exception", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ uint64_t exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ uint64_t exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     uint64_t thrown_value = 0;
     try {
@@ -101,7 +108,7 @@ TEST_CASE("c++ uint64_t exception", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ char exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ char exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     char thrown_value = '0';
     try {
@@ -113,7 +120,7 @@ TEST_CASE("c++ char exception", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ wchar exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ wchar exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     wchar_t thrown_value = 0;
     try {
@@ -125,7 +132,7 @@ TEST_CASE("c++ wchar exception", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ float exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ float exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     float thrown_value = 0;
     try {
@@ -137,7 +144,7 @@ TEST_CASE("c++ float exception", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ double exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ double exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     double thrown_value = 0;
     try {
@@ -149,7 +156,7 @@ TEST_CASE("c++ double exception", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ const char* exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ const char* exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     const char *thrown_value = 0;
     try {
@@ -167,7 +174,7 @@ public:
     NonExcTypeThrowee(int value) : value(value) { }
 };
 
-TEST_CASE("c++ any class exception", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ any class exception", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     int thrown_value = 0;
     try {
@@ -185,7 +192,7 @@ public:
     ExcTypeThrowee(int value) : value(value) { }
 };
 
-TEST_CASE("c++ std::exception child", "[cxx] [exceptions] [leaks=816]")
+TEST_CASE("c++ std::exception child", "[cxx] [exceptions] [leaks=" LEAKS "]")
 {
     int thrown_value = 0;
     try {
@@ -197,7 +204,7 @@ TEST_CASE("c++ std::exception child", "[cxx] [exceptions] [leaks=816]")
     printf("OK?\n");
 }
 
-TEST_CASE("c++ exceptions emergency pool", "[cxx] [exceptions] [ignore]")
+TEST_CASE("c++ exceptions emergency pool", "[cxx] [exceptions] [ignore] [leaks=" LEAKS "]")
 {
     void **p, **pprev = NULL;
     int thrown_value = 0;

components/esp32/cpu_start.c

@@ -117,6 +117,11 @@ struct object { long placeholder[ 10 ]; };
 void __register_frame_info (const void *begin, struct object *ob);
 extern char __eh_frame[];
 
+#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
+// workaround for C++ exception large memory allocation
+void _Unwind_SetEnableExceptionFdeSorting(unsigned char enable);
+#endif // CONFIG_COMPILER_CXX_EXCEPTIONS
+
 //If CONFIG_SPIRAM_IGNORE_NOTFOUND is set and external RAM is not found or errors out on testing, this is set to false.
 static bool s_spiram_okay=true;
 
@@ -403,6 +408,12 @@ void start_cpu0_default(void)
     assert(err == ESP_OK && "Failed to init pthread module!");
 
     do_global_ctors();
+
+#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
+    ESP_EARLY_LOGD(TAG, "Setting C++ exception workarounds.");
+    _Unwind_SetEnableExceptionFdeSorting(0);
+#endif // CONFIG_COMPILER_CXX_EXCEPTIONS
+
 #if CONFIG_ESP_INT_WDT
     esp_int_wdt_init();
     //Initialize the interrupt watch dog for CPU0.

components/esp32s2/cpu_start.c

@@ -100,6 +100,11 @@ struct object {
 void __register_frame_info (const void *begin, struct object *ob);
 extern char __eh_frame[];
 
+#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
+// workaround for C++ exception large memory allocation
+void _Unwind_SetEnableExceptionFdeSorting(unsigned char enable);
+#endif // CONFIG_COMPILER_CXX_EXCEPTIONS
+
 //If CONFIG_SPIRAM_IGNORE_NOTFOUND is set and external RAM is not found or errors out on testing, this is set to false.
 static bool s_spiram_okay = true;
 
@@ -343,6 +348,12 @@ void start_cpu0_default(void)
 #endif
 
     do_global_ctors();
+
+#ifdef CONFIG_COMPILER_CXX_EXCEPTIONS
+    ESP_EARLY_LOGD(TAG, "Setting C++ exception workarounds.");
+    _Unwind_SetEnableExceptionFdeSorting(0);
+#endif // CONFIG_COMPILER_CXX_EXCEPTIONS
+
 #if CONFIG_ESP_INT_WDT
     esp_int_wdt_init();
     //Initialize the interrupt watch dog