Merge pull request #4 from ngrewe/nil_exception

Fix throwing nil exceptions.

Test/CMakeLists.txt

@@ -26,6 +26,7 @@ set(TESTS
 	WeakReferences_arc.m
 	objc_msgSend.m
 	msgInterpose.m
+	NilException.m
 	MethodArguments.m
 )
 

Test/NilException.m

@@ -0,0 +1,49 @@
+#include "Test.h"
+
+
+#ifdef __has_attribute
+#if __has_attribute(objc_root_class)
+__attribute__((objc_root_class))
+#endif
+#endif
+@interface NSObject
+{
+  Class isa;
+}
+@end
+
+@implementation NSObject
++ (id)new
+{
+	return class_createInstance(self, 0);
+}
+@end
+int main(void)
+{
+	BOOL caught_exception = NO;
+	@try
+	{
+		@throw(nil);
+	}
+	@catch (NSObject* o)
+	{
+		assert(0);
+	}
+	@catch (id x)
+	{
+		assert(nil == x);
+		caught_exception = YES;
+	}
+	assert(caught_exception == YES);
+	caught_exception = NO;
+	@try
+	{
+		@throw(nil);
+	}
+	@catch (...)
+	{
+		caught_exception = YES;
+	}
+	assert(caught_exception == YES);
+	return 0;
+}

eh_personality.c

@@ -358,7 +358,10 @@ static inline _Unwind_Reason_Code internal_objc_personality(int version,
 	else if (!foreignException)
 	{
 		ex = objc_exception_from_header(exceptionObject);
-		thrown_class = classForObject(ex->object);
+		if (ex->object != nil)
+	        {
+			thrown_class = classForObject(ex->object);
+		}
 	}
 	else if (_objc_class_for_boxing_foreign_exception)
 	{