Index: clang/lib/Serialization/ASTReader.cpp
===================================================================
--- clang/lib/Serialization/ASTReader.cpp
+++ clang/lib/Serialization/ASTReader.cpp
@@ -4206,7 +4206,8 @@
 
   // Here comes stuff that we only do once the entire chain is loaded.
 
-  // Load the AST blocks of all of the modules that we loaded.
+  // Load the AST blocks of all of the modules that we loaded.  We can still
+  // hit errors parsing the ASTs at this point.
   for (SmallVectorImpl<ImportedModule>::iterator M = Loaded.begin(),
                                               MEnd = Loaded.end();
        M != MEnd; ++M) {
@@ -4227,7 +4228,13 @@
     F.GlobalBitOffset = TotalModulesSizeInBits;
     TotalModulesSizeInBits += F.SizeInBits;
     GlobalBitOffsetsMap.insert(std::make_pair(F.GlobalBitOffset, &F));
+  }
 
+  // Preload source locations and interesting indentifiers.
+  for (SmallVectorImpl<ImportedModule>::iterator M = Loaded.begin(),
+                                              MEnd = Loaded.end();
+       M != MEnd; ++M) {
+    ModuleFile &F = *M->Mod;
     // Preload SLocEntries.
     for (unsigned I = 0, N = F.PreloadSLocEntries.size(); I != N; ++I) {
       int Index = int(F.PreloadSLocEntries[I] - 1) + F.SLocEntryBaseID;