diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index bcf5384..e28179d 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -176,8 +176,7 @@
 /// Each instance of the Module class corresponds to a single AST file, which 
 /// may be a precompiled header, precompiled preamble, or an AST file of some 
 /// sort loaded as the main file, all of which are specific formulations of
-/// the general notion of a "module". A module may depend on another module
-/// (FIXME: or a set of other modules).
+/// the general notion of a "module". A module may depend on another module.
 class Module {
 public:  
   Module(ModuleKind Kind);
@@ -403,6 +402,9 @@
   
   /// \brief List of modules which this module depends on
   llvm::SetVector<Module *> Imports;
+  
+  /// \brief Dump debugging output for this module.
+  void dump();
 };
 
 /// \brief The manager for modules loaded by the ASTReader.
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 177d4c9..69fdf10 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -4364,7 +4364,7 @@
 }
 
 void ASTReader::dump() {
-  llvm::errs() << "*** AST File Remapping:\n";
+  llvm::errs() << "*** PCH/Module Remappings:\n";
   dumpModuleIDMap("Global bit offset map", GlobalBitOffsetsMap);
   dumpModuleIDMap("Global source location entry map", GlobalSLocEntryMap);
   dumpModuleIDMap("Global type map", GlobalTypeMap);
@@ -4375,6 +4375,12 @@
   dumpModuleIDMap("Global macro definition map", GlobalMacroDefinitionMap);
   dumpModuleIDMap("Global preprocessed entity map", 
                   GlobalPreprocessedEntityMap);
+  
+  llvm::errs() << "\n*** PCH/Modules Loaded:";
+  for (ModuleManager::ModuleConstIterator M = ModuleMgr.begin(), 
+                                       MEnd = ModuleMgr.end();
+       M != MEnd; ++M)
+    (*M)->dump();
 }
 
 /// Return the amount of memory used by memory buffers, breaking down
@@ -5477,6 +5483,40 @@
   delete static_cast<ASTSelectorLookupTable *>(SelectorLookupTable);
 }
 
+template<typename Key, typename Offset, unsigned InitialCapacity>
+static void 
+dumpLocalRemap(StringRef Name,
+               const ContinuousRangeMap<Key, Offset, InitialCapacity> &Map) {
+  if (Map.begin() == Map.end())
+    return;
+  
+  typedef ContinuousRangeMap<Key, Offset, InitialCapacity> MapType;
+  llvm::errs() << "  " << Name << ":\n";
+  for (typename MapType::const_iterator I = Map.begin(), IEnd = Map.end(); 
+       I != IEnd; ++I) {
+    llvm::errs() << "    " << I->first << " -> " << I->second
+    << "\n";
+  }
+}
+
+void Module::dump() {
+  llvm::errs() << "\nModule: " << FileName << "\n";
+  if (!Imports.empty()) {
+    llvm::errs() << "  Imports: ";
+    for (unsigned I = 0, N = Imports.size(); I != N; ++I) {
+      if (I)
+        llvm::errs() << ", ";
+      llvm::errs() << Imports[I]->FileName;
+    }
+    llvm::errs() << "\n";
+  }
+  
+  // Remapping tables.
+  llvm::errs() << "  Base source location offset: " << SLocEntryBaseOffset 
+               << '\n';
+  dumpLocalRemap("Source location offset map", SLocRemap);
+}
+
 Module *ModuleManager::lookup(StringRef Name) {
   const FileEntry *Entry = FileMgr.getFile(Name);
   return Modules[Entry];