diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 1ceed54..81cb94d 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -37,7 +37,7 @@
 Module::ExportDecl 
 ModuleMap::resolveExport(Module *Mod, 
                          const Module::UnresolvedExportDecl &Unresolved,
-                         bool Complain) {
+                         bool Complain) const {
   // We may have just a wildcard.
   if (Unresolved.Id.empty()) {
     assert(Unresolved.Wildcard && "Invalid unresolved export");
@@ -239,8 +239,8 @@
   return 0;
 }
 
-bool ModuleMap::isHeaderInUnavailableModule(const FileEntry *Header) {
-  HeadersMap::iterator Known = Headers.find(Header);
+bool ModuleMap::isHeaderInUnavailableModule(const FileEntry *Header) const {
+  HeadersMap::const_iterator Known = Headers.find(Header);
   if (Known != Headers.end())
     return !Known->second.isAvailable();
   
@@ -251,7 +251,7 @@
   // Keep walking up the directory hierarchy, looking for a directory with
   // an umbrella header.
   do {    
-    llvm::DenseMap<const DirectoryEntry *, Module *>::iterator KnownDir
+    llvm::DenseMap<const DirectoryEntry *, Module *>::const_iterator KnownDir
       = UmbrellaDirs.find(Dir);
     if (KnownDir != UmbrellaDirs.end()) {
       Module *Found = KnownDir->second;
@@ -305,15 +305,16 @@
   return false;
 }
 
-Module *ModuleMap::findModule(StringRef Name) {
-  llvm::StringMap<Module *>::iterator Known = Modules.find(Name);
+Module *ModuleMap::findModule(StringRef Name) const {
+  llvm::StringMap<Module *>::const_iterator Known = Modules.find(Name);
   if (Known != Modules.end())
     return Known->getValue();
   
   return 0;
 }
 
-Module *ModuleMap::lookupModuleUnqualified(StringRef Name, Module *Context) {
+Module *ModuleMap::lookupModuleUnqualified(StringRef Name,
+                                           Module *Context) const {
   for(; Context; Context = Context->Parent) {
     if (Module *Sub = lookupModuleQualified(Name, Context))
       return Sub;
@@ -322,7 +323,7 @@
   return findModule(Name);
 }
 
-Module *ModuleMap::lookupModuleQualified(StringRef Name, Module *Context) {
+Module *ModuleMap::lookupModuleQualified(StringRef Name, Module *Context) const{
   if (!Context)
     return findModule(Name);
   
@@ -345,10 +346,10 @@
 }
 
 bool ModuleMap::canInferFrameworkModule(const DirectoryEntry *ParentDir,
-                                        StringRef Name, bool &IsSystem) {
+                                        StringRef Name, bool &IsSystem) const {
   // Check whether we have already looked into the parent directory
   // for a module map.
-  llvm::DenseMap<const DirectoryEntry *, InferredDirectory>::iterator
+  llvm::DenseMap<const DirectoryEntry *, InferredDirectory>::const_iterator
     inferred = InferredDirectories.find(ParentDir);
   if (inferred == InferredDirectories.end())
     return false;
@@ -415,7 +416,7 @@
       if (const DirectoryEntry *ParentDir = FileMgr.getDirectory(Parent)) {
         // Check whether we have already looked into the parent directory
         // for a module map.
-        llvm::DenseMap<const DirectoryEntry *, InferredDirectory>::iterator
+        llvm::DenseMap<const DirectoryEntry *, InferredDirectory>::const_iterator
           inferred = InferredDirectories.find(ParentDir);
         if (inferred == InferredDirectories.end()) {
           // We haven't looked here before. Load a module map, if there is
@@ -560,7 +561,7 @@
 }
 
 const FileEntry *
-ModuleMap::getContainingModuleMapFile(Module *Module) {
+ModuleMap::getContainingModuleMapFile(Module *Module) const {
   if (Module->DefinitionLoc.isInvalid() || !SourceMgr)
     return 0;