Index: src/libcfa/Makefile.am
===================================================================
--- src/libcfa/Makefile.am	(revision d746bc821f67aff8f4e526f470cad8f8d18fa98f)
+++ src/libcfa/Makefile.am	(revision fcd17b2f5e850f4eee4f611d4b45b099ef8fb923)
@@ -10,7 +10,7 @@
 ## Author           : Peter A. Buhr
 ## Created On       : Sun May 31 08:54:01 2015
-## Last Modified By : Peter A. Buhr
-## Last Modified On : Thu Jul 20 23:09:34 2017
-## Update Count     : 220
+## Last Modified By : Andrew Beach
+## Last Modified On : Wed Jul 26 14:15:00 2017
+## Update Count     : 221
 ###############################################################################
 
@@ -56,5 +56,5 @@
 libobjs = ${headers:=.o}
 libsrc = libcfa-prelude.c interpose.c libhdr/libdebug.c ${headers:=.c} \
-	 assert.c exception.c typeobject.c
+	 assert.c exception.c virtual.c
 
 # not all platforms support concurrency, add option do disable it
@@ -73,5 +73,5 @@
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -O2 ${EXTRA_FLAGS} -c -o $@ $<
 
-libcfa_a-typeobject.o : typeobject.c
+libcfa_a-virtual.o : virtual.c
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -O2 ${EXTRA_FLAGS} -c -o $@ $<
 
@@ -82,5 +82,5 @@
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -D__CFA_DEBUG__ -O0 ${EXTRA_FLAGS} -c -o $@ $<
 
-libcfa_d_a-typeobject.o : typeobject.c
+libcfa_d_a-virtual.o : virtual.c
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -D__CFA_DEBUG__ -O0 ${EXTRA_FLAGS} -c -o $@ $<
 
Index: src/libcfa/Makefile.in
===================================================================
--- src/libcfa/Makefile.in	(revision d746bc821f67aff8f4e526f470cad8f8d18fa98f)
+++ src/libcfa/Makefile.in	(revision fcd17b2f5e850f4eee4f611d4b45b099ef8fb923)
@@ -154,7 +154,7 @@
 	concurrency/coroutine.c concurrency/thread.c \
 	concurrency/kernel.c concurrency/monitor.c assert.c \
-	exception.c typeobject.c \
-	concurrency/CtxSwitch-@MACHINE_TYPE@.S concurrency/alarm.c \
-	concurrency/invoke.c concurrency/preemption.c
+	exception.c virtual.c concurrency/CtxSwitch-@MACHINE_TYPE@.S \
+	concurrency/alarm.c concurrency/invoke.c \
+	concurrency/preemption.c
 am__dirstamp = $(am__leading_dot)dirstamp
 @BUILD_CONCURRENCY_TRUE@am__objects_1 = concurrency/libcfa_d_a-coroutine.$(OBJEXT) \
@@ -178,5 +178,5 @@
 	libhdr/libcfa_d_a-libdebug.$(OBJEXT) $(am__objects_2) \
 	libcfa_d_a-assert.$(OBJEXT) libcfa_d_a-exception.$(OBJEXT) \
-	libcfa_d_a-typeobject.$(OBJEXT) $(am__objects_3)
+	libcfa_d_a-virtual.$(OBJEXT) $(am__objects_3)
 am_libcfa_d_a_OBJECTS = $(am__objects_4)
 libcfa_d_a_OBJECTS = $(am_libcfa_d_a_OBJECTS)
@@ -189,7 +189,7 @@
 	concurrency/coroutine.c concurrency/thread.c \
 	concurrency/kernel.c concurrency/monitor.c assert.c \
-	exception.c typeobject.c \
-	concurrency/CtxSwitch-@MACHINE_TYPE@.S concurrency/alarm.c \
-	concurrency/invoke.c concurrency/preemption.c
+	exception.c virtual.c concurrency/CtxSwitch-@MACHINE_TYPE@.S \
+	concurrency/alarm.c concurrency/invoke.c \
+	concurrency/preemption.c
 @BUILD_CONCURRENCY_TRUE@am__objects_5 = concurrency/libcfa_a-coroutine.$(OBJEXT) \
 @BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_a-thread.$(OBJEXT) \
@@ -211,5 +211,5 @@
 	libhdr/libcfa_a-libdebug.$(OBJEXT) $(am__objects_6) \
 	libcfa_a-assert.$(OBJEXT) libcfa_a-exception.$(OBJEXT) \
-	libcfa_a-typeobject.$(OBJEXT) $(am__objects_7)
+	libcfa_a-virtual.$(OBJEXT) $(am__objects_7)
 am_libcfa_a_OBJECTS = $(am__objects_8)
 libcfa_a_OBJECTS = $(am_libcfa_a_OBJECTS)
@@ -423,5 +423,5 @@
 libobjs = ${headers:=.o}
 libsrc = libcfa-prelude.c interpose.c libhdr/libdebug.c ${headers:=.c} \
-	assert.c exception.c typeobject.c $(am__append_4)
+	assert.c exception.c virtual.c $(am__append_4)
 libcfa_a_SOURCES = ${libsrc}
 libcfa_a_CFLAGS = -nodebug -O2
@@ -598,5 +598,5 @@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_a-rational.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_a-stdlib.Po@am__quote@
-@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_a-typeobject.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_a-virtual.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_d_a-assert.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_d_a-exception.Po@am__quote@
@@ -609,5 +609,5 @@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_d_a-rational.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_d_a-stdlib.Po@am__quote@
-@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_d_a-typeobject.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libcfa_d_a-virtual.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/CtxSwitch-@MACHINE_TYPE@.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_a-alarm.Po@am__quote@
@@ -920,10 +920,10 @@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -c -o libcfa_d_a-exception.obj `if test -f 'exception.c'; then $(CYGPATH_W) 'exception.c'; else $(CYGPATH_W) '$(srcdir)/exception.c'; fi`
 
-libcfa_d_a-typeobject.obj: typeobject.c
-@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -MT libcfa_d_a-typeobject.obj -MD -MP -MF $(DEPDIR)/libcfa_d_a-typeobject.Tpo -c -o libcfa_d_a-typeobject.obj `if test -f 'typeobject.c'; then $(CYGPATH_W) 'typeobject.c'; else $(CYGPATH_W) '$(srcdir)/typeobject.c'; fi`
-@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libcfa_d_a-typeobject.Tpo $(DEPDIR)/libcfa_d_a-typeobject.Po
-@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='typeobject.c' object='libcfa_d_a-typeobject.obj' libtool=no @AMDEPBACKSLASH@
-@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
-@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -c -o libcfa_d_a-typeobject.obj `if test -f 'typeobject.c'; then $(CYGPATH_W) 'typeobject.c'; else $(CYGPATH_W) '$(srcdir)/typeobject.c'; fi`
+libcfa_d_a-virtual.obj: virtual.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -MT libcfa_d_a-virtual.obj -MD -MP -MF $(DEPDIR)/libcfa_d_a-virtual.Tpo -c -o libcfa_d_a-virtual.obj `if test -f 'virtual.c'; then $(CYGPATH_W) 'virtual.c'; else $(CYGPATH_W) '$(srcdir)/virtual.c'; fi`
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libcfa_d_a-virtual.Tpo $(DEPDIR)/libcfa_d_a-virtual.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='virtual.c' object='libcfa_d_a-virtual.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -c -o libcfa_d_a-virtual.obj `if test -f 'virtual.c'; then $(CYGPATH_W) 'virtual.c'; else $(CYGPATH_W) '$(srcdir)/virtual.c'; fi`
 
 concurrency/libcfa_d_a-alarm.o: concurrency/alarm.c
@@ -1214,10 +1214,10 @@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -c -o libcfa_a-exception.obj `if test -f 'exception.c'; then $(CYGPATH_W) 'exception.c'; else $(CYGPATH_W) '$(srcdir)/exception.c'; fi`
 
-libcfa_a-typeobject.obj: typeobject.c
-@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -MT libcfa_a-typeobject.obj -MD -MP -MF $(DEPDIR)/libcfa_a-typeobject.Tpo -c -o libcfa_a-typeobject.obj `if test -f 'typeobject.c'; then $(CYGPATH_W) 'typeobject.c'; else $(CYGPATH_W) '$(srcdir)/typeobject.c'; fi`
-@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libcfa_a-typeobject.Tpo $(DEPDIR)/libcfa_a-typeobject.Po
-@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='typeobject.c' object='libcfa_a-typeobject.obj' libtool=no @AMDEPBACKSLASH@
-@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
-@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -c -o libcfa_a-typeobject.obj `if test -f 'typeobject.c'; then $(CYGPATH_W) 'typeobject.c'; else $(CYGPATH_W) '$(srcdir)/typeobject.c'; fi`
+libcfa_a-virtual.obj: virtual.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -MT libcfa_a-virtual.obj -MD -MP -MF $(DEPDIR)/libcfa_a-virtual.Tpo -c -o libcfa_a-virtual.obj `if test -f 'virtual.c'; then $(CYGPATH_W) 'virtual.c'; else $(CYGPATH_W) '$(srcdir)/virtual.c'; fi`
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libcfa_a-virtual.Tpo $(DEPDIR)/libcfa_a-virtual.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='virtual.c' object='libcfa_a-virtual.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -c -o libcfa_a-virtual.obj `if test -f 'virtual.c'; then $(CYGPATH_W) 'virtual.c'; else $(CYGPATH_W) '$(srcdir)/virtual.c'; fi`
 
 concurrency/libcfa_a-alarm.o: concurrency/alarm.c
@@ -1513,5 +1513,5 @@
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -O2 ${EXTRA_FLAGS} -c -o $@ $<
 
-libcfa_a-typeobject.o : typeobject.c
+libcfa_a-virtual.o : virtual.c
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -O2 ${EXTRA_FLAGS} -c -o $@ $<
 
@@ -1522,5 +1522,5 @@
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -D__CFA_DEBUG__ -O0 ${EXTRA_FLAGS} -c -o $@ $<
 
-libcfa_d_a-typeobject.o : typeobject.c
+libcfa_d_a-virtual.o : virtual.c
 	${AM_V_CC}@BACKEND_CC@ -DHAVE_CONFIG_H -I. -I../.. -D__CFA_DEBUG__ -O0 ${EXTRA_FLAGS} -c -o $@ $<
 
Index: src/libcfa/virtual.c
===================================================================
--- src/libcfa/virtual.c	(revision fcd17b2f5e850f4eee4f611d4b45b099ef8fb923)
+++ src/libcfa/virtual.c	(revision fcd17b2f5e850f4eee4f611d4b45b099ef8fb923)
@@ -0,0 +1,31 @@
+//
+// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// virtual.c --
+//
+// Author           : Andrew Beach
+// Created On       : Tus Jul 11 15:10:00 2017
+// Last Modified By : Andrew Beach
+// Last Modified On : Wed Jul 26 14:24:00 2017
+// Update Count     : 1
+//
+
+#include "virtual.h"
+
+int __cfa__is_parent( struct __cfa__parent_vtable const * parent,
+    	struct __cfa__parent_vtable const * child ) {
+	do {
+		if ( parent == child )
+			return 1;
+		child = child->parent;
+	} while ( child );
+	return 0;
+}
+
+void * __cfa__virtual_cast( struct __cfa__parent_vtable const * parent,
+    	struct __cfa__parent_vtable const * const * child ) {
+	return (__cfa__is_parent(parent, *child)) ? (void *)child : (void *)0;
+}
Index: src/libcfa/virtual.h
===================================================================
--- src/libcfa/virtual.h	(revision fcd17b2f5e850f4eee4f611d4b45b099ef8fb923)
+++ src/libcfa/virtual.h	(revision fcd17b2f5e850f4eee4f611d4b45b099ef8fb923)
@@ -0,0 +1,39 @@
+//
+// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// virtual.h -- Builtins for hierarchy objects.
+//
+// Author           : Andrew Beach
+// Created On       : Tus Jul 11 15:08:00 2017
+// Last Modified By : Andrew Beach
+// Last Modified On : Wed Jul 26 14:18:00 2017
+// Update Count     : 1
+//
+
+#pragma once
+
+#ifdef __CFORALL__
+extern "C" {
+#endif
+
+// All strict/explicate vtables should have this head, showing their parent.
+struct __cfa__parent_vtable {
+    struct __cfa__parent_vtable const * const parent;
+};
+
+// Takes in two non-null pointers to type_objects.
+int __cfa__is_parent( struct __cfa__parent_vtable const * parent,
+		struct __cfa__parent_vtable const * child );
+
+// If parent is a parent of child then return child, otherwise return NULL.
+// Input pointers are none-null, child's first level should be an object with
+// a vtable
+void * __cfa__virtual_cast( struct __cfa__parent_vtable const * parent,
+		struct __cfa__parent_vtable const * const * child );
+
+#ifdef __CFORALL__
+}
+#endif