diff --git a/abi_version.c b/abi_version.c
index f6f3103..313bdfc 100644
--- a/abi_version.c
+++ b/abi_version.c
@@ -1,3 +1,4 @@
+#include "visibility.h"
 #include "objc/runtime.h"
 #include "module.h"
 #include <assert.h>
@@ -49,7 +50,7 @@ static int known_abi_count =
 	}\
 } while(0)
 
-BOOL objc_check_abi_version(unsigned long version, unsigned long module_size)
+PRIVATE BOOL objc_check_abi_version(unsigned long version, unsigned long module_size)
 {
 	struct objc_abi_version *v = NULL;
 	for (int i=0 ; i<known_abi_count ; i++)
diff --git a/alias_table.c b/alias_table.c
index bde4138..cf2c148 100644
--- a/alias_table.c
+++ b/alias_table.c
@@ -23,6 +23,7 @@
    THE SOFTWARE.
 */
 
+#include "visibility.h"
 #include "objc/runtime.h"
 #include "class.h"
 #include "lock.h"
@@ -61,7 +62,7 @@ static alias_table_internal_table *alias_table;
 #include "pool.h"
 
 
-void __objc_init_alias_table(void)
+PRIVATE void __objc_init_alias_table(void)
 {
 	alias_table = alias_table_internal_create(128);
 }
@@ -90,7 +91,7 @@ Class alias_getClass(const char *alias_name)
 	return alias->class;
 }
 
-void alias_table_insert(Alias alias)
+PRIVATE void alias_table_insert(Alias alias)
 {
 	alias_table_internal_insert(alias_table, alias);
 }
diff --git a/category_loader.c b/category_loader.c
index aaca346..04e3837 100644
--- a/category_loader.c
+++ b/category_loader.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include "objc/runtime.h"
+#include "visibility.h"
 #include "loader.h"
 
 #define BUFFER_TYPE struct objc_category
@@ -53,7 +54,7 @@ static BOOL try_load_category(struct objc_category *cat)
  * Attaches a category to its class, if the class is already loaded.  Buffers
  * it for future resolution if not.
  */
-void objc_try_load_category(struct objc_category *cat)
+PRIVATE void objc_try_load_category(struct objc_category *cat)
 {
 	if (!try_load_category(cat))
 	{
@@ -61,7 +62,7 @@ void objc_try_load_category(struct objc_category *cat)
 	}
 }
 
-void objc_load_buffered_categories(void)
+PRIVATE void objc_load_buffered_categories(void)
 {
 	BOOL shouldReshuffle = NO;
 
diff --git a/class_table.c b/class_table.c
index 7d00582..6bc5697 100644
--- a/class_table.c
+++ b/class_table.c
@@ -8,6 +8,7 @@
 #include "lock.h"
 #include "ivar.h"
 #include "dtable.h"
+#include "visibility.h"
 #include <stdlib.h>
 #include <assert.h>
 
@@ -36,13 +37,13 @@ static load_messages_table *load_table;
 
 SEL loadSel;
 
-void objc_init_load_messages_table(void)
+PRIVATE void objc_init_load_messages_table(void)
 {
 	load_table  = load_messages_create(4096);
 	loadSel = sel_registerName("load");
 }
 
-void objc_send_load_message(Class class)
+PRIVATE void objc_send_load_message(Class class)
 {
 	Class meta = class->isa;
 	for (struct objc_method_list *l=meta->methods ; NULL!=l ; l=l->next)
@@ -105,7 +106,7 @@ void objc_setDeveloperMode_np(enum objc_developer_mode_np newMode)
 // Class table manipulation
 ////////////////////////////////////////////////////////////////////////////////
 
-void class_table_insert(Class class)
+PRIVATE void class_table_insert(Class class)
 {
 	if (!objc_test_class_flag(class, objc_class_flag_resolved))
 	{
@@ -119,19 +120,19 @@ void class_table_insert(Class class)
 	class_table_internal_insert(class_table, class);
 }
 
-Class class_table_get_safe(const char *class_name)
+PRIVATE Class class_table_get_safe(const char *class_name)
 {
 	if (NULL == class_name) { return Nil; }
 	return class_table_internal_table_get(class_table, class_name);
 }
 
-Class class_table_next(void **e)
+PRIVATE Class class_table_next(void **e)
 {
 	return class_table_internal_next(class_table,
 			(struct class_table_internal_table_enumerator**)e);
 }
 
-void __objc_init_class_tables(void)
+PRIVATE void __objc_init_class_tables(void)
 {
 	class_table = class_table_internal_create(4096);
 	objc_init_load_messages_table();
@@ -141,7 +142,7 @@ void __objc_init_class_tables(void)
 // Loader functions
 ////////////////////////////////////////////////////////////////////////////////
 
-BOOL objc_resolve_class(Class cls)
+PRIVATE BOOL objc_resolve_class(Class cls)
 {
 	// Skip this if the class is already resolved.
 	if (objc_test_class_flag(cls, objc_class_flag_resolved)) { return YES; }
@@ -245,7 +246,7 @@ BOOL objc_resolve_class(Class cls)
 	return YES;
 }
 
-void objc_resolve_class_links(void)
+PRIVATE void objc_resolve_class_links(void)
 {
 	LOCK_UNTIL_RETURN(__objc_runtime_mutex);
 	Class class = unresolved_class_list;
@@ -365,7 +366,7 @@ static void reload_class(struct objc_class *class, struct objc_class *old)
 /**
  * Loads a class.  This function assumes that the runtime mutex is locked.
  */
-void objc_load_class(struct objc_class *class)
+PRIVATE void objc_load_class(struct objc_class *class)
 {
 	struct objc_class *existingClass = class_table_get_safe(class->name);
 	if (Nil != existingClass)
diff --git a/dtable.c b/dtable.c
index 22d0efd..57f0125 100644
--- a/dtable.c
+++ b/dtable.c
@@ -8,12 +8,13 @@
 #include "method_list.h"
 #include "slot_pool.h"
 #include "dtable.h"
+#include "visibility.h"
 
-dtable_t __objc_uninstalled_dtable;
+PRIVATE dtable_t __objc_uninstalled_dtable;
 
 /** Head of the list of temporary dtables.  Protected by initialize_lock. */
-InitializingDtable *temporary_dtables;
-mutex_t initialize_lock;
+PRIVATE InitializingDtable *temporary_dtables;
+PRIVATE mutex_t initialize_lock;
 static uint32_t dtable_depth = 8;
 
 
@@ -55,14 +56,14 @@ struct objc_dtable
 	mutex_t lock;
 };
 
-void __objc_init_dispatch_tables ()
+PRIVATE void __objc_init_dispatch_tables ()
 {
 	INIT_LOCK(initialize_lock);
 }
 
 Class class_getSuperclass(Class);
 
-void __objc_update_dispatch_table_for_class(Class cls)
+PRIVATE void __objc_update_dispatch_table_for_class(Class cls)
 {
 	static BOOL warned = NO;
 	if (!warned)
@@ -95,7 +96,7 @@ static dtable_t create_dtable_for_class(Class class)
 }
 
 
-void objc_resize_dtables(uint32_t newSize)
+PRIVATE void objc_resize_dtables(uint32_t newSize)
 {
 	if (1<<dtable_depth > newSize) { return; }
 	dtable_depth <<= 1;
@@ -223,7 +224,7 @@ static void update_dtable(dtable_t dtable)
 	SparseArrayDestroy(methods);
 }
 
-void objc_update_dtable_for_class(Class cls)
+PRIVATE void objc_update_dtable_for_class(Class cls)
 {
 	dtable_t dtable = dtable_for_class(cls);
 	// Be lazy about constructing the slot list - don't do it unless we actually
@@ -236,7 +237,7 @@ void objc_update_dtable_for_class(Class cls)
 
 }
 
-struct objc_slot* objc_dtable_lookup(dtable_t dtable, uint32_t uid)
+PRIVATE struct objc_slot* objc_dtable_lookup(dtable_t dtable, uint32_t uid)
 {
 	if (NULL == dtable) { return NULL; }
 
@@ -273,7 +274,7 @@ struct objc_slot* objc_dtable_lookup(dtable_t dtable, uint32_t uid)
 	}
 	return NULL;
 }
-dtable_t objc_copy_dtable_for_class(dtable_t old, Class cls)
+PRIVATE dtable_t objc_copy_dtable_for_class(dtable_t old, Class cls)
 {
 	dtable_t dtable = calloc(1, sizeof(struct objc_dtable));
 	dtable->cls = cls;
@@ -284,7 +285,7 @@ dtable_t objc_copy_dtable_for_class(dtable_t old, Class cls)
 #else
 
 
-void __objc_init_dispatch_tables ()
+PRIVATE void __objc_init_dispatch_tables ()
 {
 	INIT_LOCK(initialize_lock);
 	__objc_uninstalled_dtable = SparseArrayNewWithDepth(dtable_depth);
@@ -393,7 +394,7 @@ static void mergeMethodsFromSuperclass(Class super, Class cls, SparseArray *meth
 
 Class class_getSuperclass(Class);
 
-void objc_update_dtable_for_class(Class cls)
+PRIVATE void objc_update_dtable_for_class(Class cls)
 {
 	// Only update real dtables
 	if (!classHasDtable(cls)) { return; }
@@ -409,7 +410,7 @@ void objc_update_dtable_for_class(Class cls)
 	mergeMethodsFromSuperclass(cls, cls, methods);
 	SparseArrayDestroy(methods);
 }
-void __objc_update_dispatch_table_for_class(Class cls)
+PRIVATE void __objc_update_dispatch_table_for_class(Class cls)
 {
 	static BOOL warned = NO;
 	if (!warned)
@@ -472,7 +473,7 @@ static SparseArray *create_dtable_for_class(Class class)
 
 Class class_table_next(void **e);
 
-void objc_resize_dtables(uint32_t newSize)
+PRIVATE void objc_resize_dtables(uint32_t newSize)
 {
 	// If dtables already have enough space to store all registered selectors, do nothing
 	if (1<<dtable_depth > newSize) { return; }
@@ -498,7 +499,7 @@ void objc_resize_dtables(uint32_t newSize)
 	}
 }
 
-dtable_t objc_copy_dtable_for_class(dtable_t old, Class cls)
+PRIVATE dtable_t objc_copy_dtable_for_class(dtable_t old, Class cls)
 {
 	return SparseArrayCopy(old);
 }
@@ -510,7 +511,7 @@ void objc_resolve_class(Class);
 /**
  * Send a +initialize message to the receiver, if required.  
  */
-void objc_send_initialize(id object)
+PRIVATE void objc_send_initialize(id object)
 {
 	Class class = object->isa;
 	// If the first message is sent to an instance (weird, but possible and
diff --git a/eh_personality.c b/eh_personality.c
index f5dc612..eeb46d5 100644
--- a/eh_personality.c
+++ b/eh_personality.c
@@ -13,8 +13,8 @@
 /**
  * Class of exceptions to distinguish between this and other exception types.
  */
-const uint64_t objc_exception_class = EXCEPTION_CLASS('G','N','U','C','O','B','J','C');
-const uint64_t cxx_exception_class = EXCEPTION_CLASS('G','N','U','C','C','+','+','\0');
+static const uint64_t objc_exception_class = EXCEPTION_CLASS('G','N','U','C','O','B','J','C');
+static const uint64_t cxx_exception_class = EXCEPTION_CLASS('G','N','U','C','C','+','+','\0');
 
 /**
  * Structure used as a header on thrown exceptions.  
@@ -96,9 +96,9 @@ void objc_exception_throw(id object)
 	abort();
 }
 
-Class get_type_table_entry(struct _Unwind_Context *context,
-                           struct dwarf_eh_lsda *lsda,
-                           int filter)
+static Class get_type_table_entry(struct _Unwind_Context *context,
+                                  struct dwarf_eh_lsda *lsda,
+                                  int filter)
 {
 	dw_eh_ptr_t record = lsda->type_table -
 		dwarf_size_of_fixed_size_field(lsda->type_table_encoding)*filter;
diff --git a/hash_table.c b/hash_table.c
index c89a860..0cd5f4f 100644
--- a/hash_table.c
+++ b/hash_table.c
@@ -1,10 +1,11 @@
 #include "objc/toydispatch.h"
 #include "lock.h"
+#include "visibility.h"
 
 
 static dispatch_queue_t garbage_queue;
 
-void objc_collect_garbage_data(void(*cleanup)(void*), void *garbage)
+PRIVATE void objc_collect_garbage_data(void(*cleanup)(void*), void *garbage)
 {
 	if (0 == garbage_queue)
 	{
diff --git a/ivar.c b/ivar.c
index 987f9eb..83fadc9 100644
--- a/ivar.c
+++ b/ivar.c
@@ -3,11 +3,12 @@
 #include "objc/runtime.h"
 #include "class.h"
 #include "ivar.h"
+#include "visibility.h"
 
 ptrdiff_t objc_alignof_type(const char *);
 ptrdiff_t objc_sizeof_type(const char *);
 
-void objc_compute_ivar_offsets(Class class)
+PRIVATE void objc_compute_ivar_offsets(Class class)
 {
 	int i = 0;
 	/* If this class was compiled with support for late-bound ivars, the
diff --git a/protocol.c b/protocol.c
index be2a85e..316bba1 100644
--- a/protocol.c
+++ b/protocol.c
@@ -3,6 +3,7 @@
 #include "properties.h"
 #include "class.h"
 #include "lock.h"
+#include "visibility.h"
 #include <stdlib.h>
 
 #define BUFFER_TYPE struct objc_protocol_list
@@ -191,7 +192,7 @@ static BOOL init_protocols(struct objc_protocol_list *protocols)
 	return YES;
 }
 
-void objc_init_protocols(struct objc_protocol_list *protocols)
+PRIVATE void objc_init_protocols(struct objc_protocol_list *protocols)
 {
 	if (!init_protocols(protocols))
 	{
diff --git a/sarray2.c b/sarray2.c
index 4379b7a..9a64295 100644
--- a/sarray2.c
+++ b/sarray2.c
@@ -4,6 +4,7 @@
 #include <assert.h>
 
 #include "sarray2.h"
+#include "visibility.h"
 
 static void *EmptyArrayData[256];
 static SparseArray EmptyArray = { 0xff, 0, 0, (void**)&EmptyArrayData};
@@ -27,7 +28,7 @@ static void init_pointers(SparseArray * sarray)
 		}
 	}
 }
-SparseArray * SparseArrayNewWithDepth(uint32_t depth)
+PRIVATE SparseArray * SparseArrayNewWithDepth(uint32_t depth)
 {
 	SparseArray * sarray = calloc(1, sizeof(SparseArray));
 	sarray->refCount = 1;
@@ -37,11 +38,11 @@ SparseArray * SparseArrayNewWithDepth(uint32_t depth)
 	return sarray;
 }
 
-SparseArray *SparseArrayNew()
+PRIVATE SparseArray *SparseArrayNew()
 {
 	return SparseArrayNewWithDepth(32);
 }
-SparseArray *SparseArrayExpandingArray(SparseArray *sarray)
+PRIVATE SparseArray *SparseArrayExpandingArray(SparseArray *sarray)
 {
 	// Expanding a child sarray has undefined results.
 	assert(sarray->refCount == 1);
@@ -113,13 +114,13 @@ static void *SparseArrayFind(SparseArray * sarray, uint32_t * index)
 	return SARRAY_EMPTY;
 }
 
-void *SparseArrayNext(SparseArray * sarray, uint32_t * idx)
+PRIVATE void *SparseArrayNext(SparseArray * sarray, uint32_t * idx)
 {
 	(*idx)++;
 	return SparseArrayFind(sarray, idx);
 }
 
-void SparseArrayInsert(SparseArray * sarray, uint32_t index, void *value)
+PRIVATE void SparseArrayInsert(SparseArray * sarray, uint32_t index, void *value)
 {
 	if (sarray->shift > 0)
 	{
@@ -158,7 +159,7 @@ void SparseArrayInsert(SparseArray * sarray, uint32_t index, void *value)
 	}
 }
 
-SparseArray *SparseArrayCopy(SparseArray * sarray)
+PRIVATE SparseArray *SparseArrayCopy(SparseArray * sarray)
 {
 	SparseArray *copy = calloc(1, sizeof(SparseArray));
 	copy->refCount = 1;
@@ -180,7 +181,7 @@ SparseArray *SparseArrayCopy(SparseArray * sarray)
 	return copy;
 }
 
-void SparseArrayDestroy(SparseArray * sarray)
+PRIVATE void SparseArrayDestroy(SparseArray * sarray)
 {
 	// Don't really delete this sarray if its ref count is > 0
 	if (sarray == &EmptyArray || 
diff --git a/selector_table.c b/selector_table.c
index 39ee0e8..dad5d27 100644
--- a/selector_table.c
+++ b/selector_table.c
@@ -14,6 +14,7 @@
 #include "method_list.h"
 #include "class.h"
 #include "selector.h"
+#include "visibility.h"
 
 #ifdef TYPE_DEPENDENT_DISPATCH
 #	define TDD(x) x
@@ -219,7 +220,7 @@ void objc_resize_dtables(uint32_t);
 /**
  * Create data structures to store selectors.
  */
-void __objc_init_selector_tables()
+PRIVATE void __objc_init_selector_tables()
 {
 	selector_list = SparseArrayNew();
 	INIT_LOCK(selector_table_lock);
@@ -296,7 +297,7 @@ static inline void register_selector_locked(SEL aSel)
 /**
  * Registers a selector.  This assumes that the argument is never deallocated.
  */
-SEL objc_register_selector(SEL aSel)
+PRIVATE SEL objc_register_selector(SEL aSel)
 {
 	if (isSelRegistered(aSel))
 	{
@@ -479,7 +480,7 @@ unsigned sel_copyTypedSelectors_np(const char *selName, SEL *const sels, unsigne
 	return found;
 }
 
-void objc_register_selectors_from_list(struct objc_method_list *l)
+PRIVATE void objc_register_selectors_from_list(struct objc_method_list *l)
 {
 	for (int i=0 ; i<l->count ; i++)
 	{
@@ -491,14 +492,14 @@ void objc_register_selectors_from_list(struct objc_method_list *l)
 /**
  * Register all of the (unregistered) selectors that are used in a class.
  */
-void objc_register_selectors_from_class(Class class)
+PRIVATE void objc_register_selectors_from_class(Class class)
 {
 	for (struct objc_method_list *l=class->methods ; NULL!=l ; l=l->next)
 	{
 		objc_register_selectors_from_list(l);
 	}
 }
-void objc_register_selector_array(SEL selectors, unsigned long count)
+PRIVATE void objc_register_selector_array(SEL selectors, unsigned long count)
 {
 	// GCC is broken and always sets the count to 0, so we ignore count until
 	// we can throw stupid and buggy compilers in the bin.
@@ -515,7 +516,7 @@ void objc_register_selector_array(SEL selectors, unsigned long count)
  * All of the functions in this section are deprecated and should not be used
  * in new code.
  */
-
+#ifdef NO_LEGACY
 SEL sel_get_typed_uid (const char *name, const char *types)
 {
 	if (NULL == name) { return NULL; }
@@ -590,6 +591,8 @@ BOOL sel_eq(SEL s1, SEL s2)
 	return sel_isEqual(s1, s2);
 }
 
+#endif // NO_LEGACY
+
 /*
  * Some simple sanity tests.
  */
diff --git a/statics_loader.c b/statics_loader.c
index 627d4a5..6b2b1d4 100644
--- a/statics_loader.c
+++ b/statics_loader.c
@@ -3,6 +3,7 @@
 #include "objc/runtime.h"
 #include "module.h"
 #include "constant_string.h"
+#include "visibility.h"
 
 #define BUFFER_TYPE struct objc_static_instance_list
 #include "buffer.h"
@@ -39,7 +40,7 @@ static BOOL try_init_statics(struct objc_static_instance_list *statics)
 	}
 	return YES;
 }
-void objc_init_statics(struct objc_static_instance_list *statics)
+PRIVATE void objc_init_statics(struct objc_static_instance_list *statics)
 {
 	if (!try_init_statics(statics))
 	{
@@ -47,7 +48,7 @@ void objc_init_statics(struct objc_static_instance_list *statics)
 	}
 }
 
-void objc_init_buffered_statics(void)
+PRIVATE void objc_init_buffered_statics(void)
 {
 	BOOL shouldReshuffle = NO;
 
diff --git a/visibility.h b/visibility.h
new file mode 100644
index 0000000..6521dec
--- /dev/null
+++ b/visibility.h
@@ -0,0 +1,8 @@
+#if defined _WIN32 || defined __CYGWIN__
+#	define PUBLIC __attribute__((dllexport))
+#	define PRIVATE
+#else
+#	define PUBLIC __attribute__ ((visibility("default")))
+#	define PRIVATE  __attribute__ ((visibility("hidden")))
+#endif
+