4 files changed, 20 insertions, 9 deletions
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index bd019e0cf23..1106e48e910 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -636,14 +636,8 @@ ModuleKey CompilerInstance::loadModule(SourceLocation ImportLoc,
     CurFile = SourceMgr.getFileEntryForID(SourceMgr.getMainFileID());
 
   // Search for a module with the given name.
-  std::string Filename = ModuleName.getName().str();
-  Filename += ".pcm";
-  const DirectoryLookup *CurDir = 0;  
   const FileEntry *ModuleFile
-    = PP->getHeaderSearchInfo().LookupFile(Filename, /*isAngled=*/false,
-                                           /*FromDir=*/0, CurDir, CurFile, 
-                                           /*SearchPath=*/0, 
-                                           /*RelativePath=*/0);
+    = PP->getHeaderSearchInfo().lookupModule(ModuleName.getName());
   if (!ModuleFile) {
     getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
       << ModuleName.getName()
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 7ea31613bd3..e7b88542241 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -576,6 +576,10 @@ static void HeaderSearchOptsToArgs(const HeaderSearchOptions &Opts,
     Res.push_back("-resource-dir");
     Res.push_back(Opts.ResourceDir);
   }
+  if (!Opts.ModuleCachePath.empty()) {
+    Res.push_back("-fmodule-cache-path");
+    Res.push_back(Opts.ModuleCachePath);
+  }
   if (!Opts.UseStandardIncludes)
     Res.push_back("-nostdinc");
   if (!Opts.UseStandardCXXIncludes)
@@ -1378,7 +1382,8 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
   if (const Arg *A = Args.getLastArg(OPT_stdlib_EQ))
     Opts.UseLibcxx = (strcmp(A->getValue(Args), "libc++") == 0);
   Opts.ResourceDir = Args.getLastArgValue(OPT_resource_dir);
-
+  Opts.ModuleCachePath = Args.getLastArgValue(OPT_fmodule_cache_path);
+  
   // Add -I..., -F..., and -index-header-map options in order.
   bool IsIndexHeaderMap = false;
   for (arg_iterator it = Args.filtered_begin(OPT_I, OPT_F, 
@@ -1426,7 +1431,7 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
                  ((*it)->getOption().matches(OPT_cxx_isystem) ?
                    frontend::CXXSystem : frontend::System),
                  true, false, !(*it)->getOption().matches(OPT_iwithsysroot));
-
+  
   // FIXME: Need options for the various environment variables!
 }
 
diff --git a/clang/lib/Frontend/InitHeaderSearch.cpp b/clang/lib/Frontend/InitHeaderSearch.cpp
index 08af5322675..05152a77b2f 100644
--- a/clang/lib/Frontend/InitHeaderSearch.cpp
+++ b/clang/lib/Frontend/InitHeaderSearch.cpp
@@ -1161,5 +1161,7 @@ void clang::ApplyHeaderSearchOptions(HeaderSearch &HS,
   if (HSOpts.UseStandardIncludes)
     Init.AddDefaultSystemIncludePaths(Lang, Triple, HSOpts);
 
+  HS.setModuleCachePath(HSOpts.ModuleCachePath);
+  
   Init.Realize(Lang);
 }
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 0ba76327421..36826756b8b 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -98,6 +98,16 @@ const HeaderMap *HeaderSearch::CreateHeaderMap(const FileEntry *FE) {
   return 0;
 }
 
+const FileEntry *HeaderSearch::lookupModule(StringRef ModuleName) {
+  // If we don't have a module cache path, we can't do anything.
+  if (ModuleCachePath.empty())
+    return 0;
+  
+  llvm::SmallString<256> FileName(ModuleCachePath);
+  llvm::sys::path::append(FileName, ModuleName + ".pcm");
+  return getFileMgr().getFile(FileName);
+}
+
 //===----------------------------------------------------------------------===//
 // File lookup within a DirectoryLookup scope
 //===----------------------------------------------------------------------===//