Added test of forwarding mechanisms.

Test/CMakeLists.txt

@@ -9,6 +9,7 @@ set(TESTS
 	BoxedForeignException.m
 	ExceptionTest.m
 	ForeignException.m
+	Forward.m
 	NestedExceptions.m
 	PropertyAttributeTest.m
 	PropertyIntrospectionTest.m

Test/Forward.m

@@ -0,0 +1,73 @@
+#include "Test.h"
+#include <objc/hooks.h>
+
+@interface Forward : Test
+- (id)forwardingTargetForSelector: (SEL)sel;
+@end
+
+id target;
+
+@implementation Forward
+- (id)forwardingTargetForSelector: (SEL)sel
+{
+	return target;
+}
+@end
+
+@interface Forward2 : Test
+@end
+
+@interface ForwardingTarget : Test
+@end
+
+BOOL forwardingTargetCalled;
+
+@implementation ForwardingTarget
+- (void)foo: (int)x
+{
+	assert(x == 42);
+	forwardingTargetCalled = YES;
+}
+@end
+@implementation Forward2
+- (void)forward: (int)x
+{
+	[target foo: x];
+}
+@end
+
+static id proxy_lookup(id receiver, SEL selector)
+{
+	if (class_respondsToSelector(object_getClass(receiver), @selector(forwardingTargetForSelector:)))
+	{
+		return [receiver forwardingTargetForSelector: selector];
+	}
+	return nil;
+}
+
+static struct objc_slot* forward(id receiver, SEL selector)
+{
+	__thread static struct objc_slot forwardingSlot;
+	if (class_respondsToSelector(object_getClass(receiver), @selector(forward:)))
+	{
+		forwardingSlot.method = class_getMethodImplementation(object_getClass(receiver), @selector(forward:));
+		return &forwardingSlot;
+	}
+	assert(0);
+}
+
+int main(void)
+{
+	objc_proxy_lookup = proxy_lookup;
+	__objc_msg_forward3 = forward;
+	target = [ForwardingTarget new];
+	id proxy = [Forward new];
+	[proxy foo: 42];
+	[proxy dealloc];
+	assert(forwardingTargetCalled == YES);
+	forwardingTargetCalled = NO;
+	proxy = [Forward2 new];
+	[proxy foo: 42];
+	[proxy dealloc];
+	assert(forwardingTargetCalled == YES);
+}