diff --git a/utils/llvm-build/llvmbuild/componentinfo.py b/utils/llvm-build/llvmbuild/componentinfo.py
index e15dbda..22ce0b4 100644
--- a/utils/llvm-build/llvmbuild/componentinfo.py
+++ b/utils/llvm-build/llvmbuild/componentinfo.py
@@ -37,6 +37,17 @@
         # under.
         self.parent = parent
 
+    def get_component_references(self):
+        """get_component_references() -> iter
+
+        Return an iterator over the named references to other components from
+        this object. Items are of the form (reference-type, component-name).
+        """
+
+        # Parent references are handled specially.
+        for r in self.dependencies:
+            yield ('dependency', r)
+
 class GroupComponentInfo(ComponentInfo):
     """
     Group components have no semantics as far as the build system are concerned,
@@ -81,6 +92,14 @@
         # considered part of.
         self.add_to_library_groups = list(add_to_library_groups)
 
+    def get_component_references(self):
+        for r in ComponentInfo.get_component_references(self):
+            yield r
+        for r in self.required_libraries:
+            yield ('required library', r)
+        for r in self.add_to_library_groups:
+            yield ('library group', r)
+
 class LibraryGroupComponentInfo(ComponentInfo):
     type_name = 'LibraryGroup'
 
@@ -104,6 +123,14 @@
         # considered part of.
         self.add_to_library_groups = list(add_to_library_groups)
 
+    def get_component_references(self):
+        for r in ComponentInfo.get_component_references(self):
+            yield r
+        for r in self.required_libraries:
+            yield ('required library', r)
+        for r in self.add_to_library_groups:
+            yield ('library group', r)
+
 class ToolComponentInfo(ComponentInfo):
     type_name = 'Tool'
 
@@ -121,6 +148,12 @@
         # tool.
         self.required_libraries = list(required_libraries)
 
+    def get_component_references(self):
+        for r in ComponentInfo.get_component_references(self):
+            yield r
+        for r in self.required_libraries:
+            yield ('required library', r)
+
 class BuildToolComponentInfo(ToolComponentInfo):
     type_name = 'BuildTool'
 
diff --git a/utils/llvm-build/llvmbuild/main.py b/utils/llvm-build/llvmbuild/main.py
index 57233a0..a734ac1 100644
--- a/utils/llvm-build/llvmbuild/main.py
+++ b/utils/llvm-build/llvmbuild/main.py
@@ -1,8 +1,12 @@
-import pprint
 import os
+import sys
 
 import componentinfo
 
+from util import *
+
+###
+
 class LLVMProjectInfo(object):
     @staticmethod
     def load_infos_from_path(llvmbuild_source_root):
@@ -35,9 +39,62 @@
         return LLVMProjectInfo(source_root, infos)
 
     def __init__(self, source_root, component_infos):
+        # Store our simple ivars.
         self.source_root = source_root
         self.component_infos = component_infos
 
+        # Create the component info map and validate that component names are
+        # unique.
+        self.component_info_map = {}
+        for ci in component_infos:
+            existing = self.component_info_map.get(ci.name)
+            if existing is not None:
+                # We found a duplicate component name, report it and error out.
+                fatal("found duplicate component %r (at %r and %r)" % (
+                        ci.name, ci.subpath, existing.subpath))
+            self.component_info_map[ci.name] = ci
+
+        # Topologically order the component information according to their
+        # component references.
+        def visit_component_info(ci, current_stack, current_set):
+            # Check for a cycles.
+            if ci in current_set:
+                # We found a cycle, report it and error out.
+                cycle_description = ' -> '.join(
+                    '%r (%s)' % (ci.name, relation)
+                    for relation,ci in current_stack)
+                fatal("found cycle to %r after following: %s -> %s" % (
+                        ci.name, cycle_description, ci.name))
+
+            # If we have already visited this item, we are done.
+            if ci not in components_to_visit:
+                return
+
+            # Otherwise, mark the component info as visited and traverse.
+            components_to_visit.remove(ci)
+
+            for relation,referent_name in ci.get_component_references():
+                # Validate that the reference is ok.
+                referent = self.component_info_map.get(referent_name)
+                if referent is None:
+                    fatal("component %r has invalid reference %r (via %r)" % (
+                            ci.name, referent_name, relation))
+
+                # Visit the reference.
+                current_stack.append((relation,ci))
+                current_set.add(ci)
+                visit_component_info(referent, current_stack, current_set)
+                current_set.remove(ci)
+                current_stack.pop()
+
+            # Finally, add the component info to the ordered list.
+            self.ordered_component_infos.append(ci)
+
+        self.ordered_component_infos = []
+        components_to_visit = set(component_infos)
+        while components_to_visit:
+            visit_component_info(iter(components_to_visit).next(), [], set())
+
 def main():
     from optparse import OptionParser, OptionGroup
     parser = OptionParser("usage: %prog [options]")