Rework C++ exception interop again.

We now, the first time we encounter a foreign exception, throw a C++
exception through a frame that has a custom personality function and
probe the layout of the __cxa_exception structure.
We then use the offsets learned from this along with the public ABI
functions for allocating the structure.

At the same time, add a test that we are correctly setting the count of
uncaught exceptions.

Fixes #146

CMakeLists.txt

@@ -84,7 +84,6 @@ if (WIN32)
 	list(APPEND libobjc_CXX_SRCS eh_win32_msvc.cc)
 else ()
 	list(APPEND libobjc_C_SRCS eh_personality.c)
-	set(libobjcxx_CXX_SRCS objcxx_eh.cc libstdcxx_current_primary_exception.cc)
 endif (WIN32)
 
 
@@ -302,10 +301,10 @@ if (ENABLE_OBJCXX)
 			endif()
 		endif ()
 		add_custom_command(OUTPUT eh_trampoline.S
-			COMMAND ${CMAKE_CXX_COMPILER} -fPIC -S "${CMAKE_SOURCE_DIR}/eh_trampoline.cc" -o - -fexceptions -fno-inline | sed "s/__gxx_personality_v0/test_eh_personality/g" > "${CMAKE_BINARY_DIR}/eh_trampoline.S"
+			COMMAND ${CMAKE_CXX_COMPILER} ${CMAKE_CXX_FLAGS} -fPIC -S "${CMAKE_SOURCE_DIR}/eh_trampoline.cc" -o - -fexceptions -fno-inline | sed "s/__gxx_personality_v0/test_eh_personality/g" > "${CMAKE_BINARY_DIR}/eh_trampoline.s"
 			MAIN_DEPENDENCY eh_trampoline.cc)
-		list(APPEND libobjc_ASM_SRCS eh_trampoline.S)
-		list(APPEND libobjc_CXX_SRCS cxx_eh_setup.cc)
+		list(APPEND libobjc_ASM_SRCS eh_trampoline.s)
+		list(APPEND libobjc_CXX_SRCS objcxx_eh.cc)
 	endif ()
 endif (ENABLE_OBJCXX)
 

Test/ObjCXXEHInterop.m

@@ -3,6 +3,7 @@
 #import "stdio.h"
 
 void poke_objcxx(void);
+void check_uncaught_count(void);
 
 void rethrow(id x)
 {
@@ -18,5 +19,6 @@ int main(void)
   } @catch (Test *localException) {
     printf("In NS_HANDLER block, %p\n", localException);
   }
+  check_uncaught_count();
 }
 

Test/ObjCXXEHInterop.mm

@@ -1,6 +1,17 @@
 #import "Test.h"
 #import "stdio.h"
 
+#if __has_include(<cxxabi.h>)
+#include <cxxabi.h>
+extern "C" void check_uncaught_count(void)
+{
+	assert(__cxxabiv1::__cxa_get_globals()->uncaughtExceptions == 0);
+}
+#else
+extern "C" void check_uncaught_count(void) {}
+#error
+#endif
+
 extern "C" void rethrow(id);
 
 

eh_personality.c

@@ -503,6 +503,8 @@ BEGIN_PERSONALITY_FUNCTION(__gnustep_objcxx_personality_v0)
 		if (0 == ex->cxx_exception)
 		{
 			ex->cxx_exception = objc_init_cxx_exception(ex->object);
+			ex->cxx_exception->private_1 = exceptionObject->private_1;
+			ex->cxx_exception->private_2 = exceptionObject->private_2;
 		}
 		exceptionObject = ex->cxx_exception;
 		exceptionClass = cxx_exception_class;

eh_trampoline.cc

@@ -1,5 +1,6 @@
 void cxx_throw();
 
+__attribute((visibility("hidden"))
 int eh_trampoline()
 {
 	struct X { ~X() {} } x;