diff --git a/clang/include/clang/Serialization/ASTBitCodes.h b/clang/include/clang/Serialization/ASTBitCodes.h
--- a/clang/include/clang/Serialization/ASTBitCodes.h
+++ b/clang/include/clang/Serialization/ASTBitCodes.h
@@ -365,6 +365,9 @@
       /// Record code for the diagnostic options table.
       DIAGNOSTIC_OPTIONS,
 
+      /// Record code for the headers search paths.
+      HEADER_SEARCH_PATHS,
+
       /// Record code for \#pragma diagnostic mappings.
       DIAG_PRAGMA_MAPPINGS,
     };
diff --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -1321,6 +1321,8 @@
                                      ASTReaderListener &Listener);
   static bool ParseHeaderSearchOptions(const RecordData &Record, bool Complain,
                                        ASTReaderListener &Listener);
+  static bool ParseHeaderSearchPaths(const RecordData &Record, bool Complain,
+                                     ASTReaderListener &Listener);
   static bool ParsePreprocessorOptions(const RecordData &Record, bool Complain,
                                        ASTReaderListener &Listener,
                                        std::string &SuggestedPredefines);
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -4642,6 +4642,13 @@
         Result = OutOfDate; // Don't return early.  Read the signature.
       break;
     }
+    case HEADER_SEARCH_PATHS: {
+      bool Complain = (ClientLoadCapabilities & ARR_ConfigurationMismatch) == 0;
+      if (!AllowCompatibleConfigurationMismatch &&
+          ParseHeaderSearchPaths(Record, Complain, *Listener))
+        Result = ConfigurationMismatch;
+      break;
+    }
     case DIAG_PRAGMA_MAPPINGS:
       if (!F)
         break;
@@ -5706,6 +5713,27 @@
   HeaderSearchOptions HSOpts;
   unsigned Idx = 0;
   HSOpts.Sysroot = ReadString(Record, Idx);
+  HSOpts.ResourceDir = ReadString(Record, Idx);
+  HSOpts.ModuleCachePath = ReadString(Record, Idx);
+  HSOpts.ModuleUserBuildPath = ReadString(Record, Idx);
+  HSOpts.DisableModuleHash = Record[Idx++];
+  HSOpts.ImplicitModuleMaps = Record[Idx++];
+  HSOpts.ModuleMapFileHomeIsCwd = Record[Idx++];
+  HSOpts.UseBuiltinIncludes = Record[Idx++];
+  HSOpts.UseStandardSystemIncludes = Record[Idx++];
+  HSOpts.UseStandardCXXIncludes = Record[Idx++];
+  HSOpts.UseLibcxx = Record[Idx++];
+  std::string SpecificModuleCachePath = ReadString(Record, Idx);
+
+  return Listener.ReadHeaderSearchOptions(HSOpts, SpecificModuleCachePath,
+                                          Complain);
+}
+
+bool ASTReader::ParseHeaderSearchPaths(const RecordData &Record,
+                                       bool Complain,
+                                       ASTReaderListener &Listener) {
+  HeaderSearchOptions HSOpts;
+  unsigned Idx = 0;
 
   // Include entries.
   for (unsigned N = Record[Idx++]; N; --N) {
@@ -5725,20 +5753,8 @@
     HSOpts.SystemHeaderPrefixes.emplace_back(std::move(Prefix), IsSystemHeader);
   }
 
-  HSOpts.ResourceDir = ReadString(Record, Idx);
-  HSOpts.ModuleCachePath = ReadString(Record, Idx);
-  HSOpts.ModuleUserBuildPath = ReadString(Record, Idx);
-  HSOpts.DisableModuleHash = Record[Idx++];
-  HSOpts.ImplicitModuleMaps = Record[Idx++];
-  HSOpts.ModuleMapFileHomeIsCwd = Record[Idx++];
-  HSOpts.UseBuiltinIncludes = Record[Idx++];
-  HSOpts.UseStandardSystemIncludes = Record[Idx++];
-  HSOpts.UseStandardCXXIncludes = Record[Idx++];
-  HSOpts.UseLibcxx = Record[Idx++];
-  std::string SpecificModuleCachePath = ReadString(Record, Idx);
-
-  return Listener.ReadHeaderSearchOptions(HSOpts, SpecificModuleCachePath,
-                                          Complain);
+  // TODO: implement checking and warnings for path mismatches.
+  return false;
 }
 
 bool ASTReader::ParsePreprocessorOptions(const RecordData &Record,
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1327,6 +1327,7 @@
   BLOCK(UNHASHED_CONTROL_BLOCK);
   RECORD(SIGNATURE);
   RECORD(DIAGNOSTIC_OPTIONS);
+  RECORD(HEADER_SEARCH_PATHS);
   RECORD(DIAG_PRAGMA_MAPPINGS);
 
 #undef RECORD
@@ -1446,6 +1447,29 @@
   // are generally transient files and will almost always be overridden.
   Stream.EmitRecord(DIAGNOSTIC_OPTIONS, Record);
 
+  // Header search paths.
+  Record.clear();
+  const HeaderSearchOptions &HSOpts
+    = PP.getHeaderSearchInfo().getHeaderSearchOpts();
+
+  // Include entries.
+  Record.push_back(HSOpts.UserEntries.size());
+  for (unsigned I = 0, N = HSOpts.UserEntries.size(); I != N; ++I) {
+    const HeaderSearchOptions::Entry &Entry = HSOpts.UserEntries[I];
+    AddString(Entry.Path, Record);
+    Record.push_back(static_cast<unsigned>(Entry.Group));
+    Record.push_back(Entry.IsFramework);
+    Record.push_back(Entry.IgnoreSysRoot);
+  }
+
+  // System header prefixes.
+  Record.push_back(HSOpts.SystemHeaderPrefixes.size());
+  for (unsigned I = 0, N = HSOpts.SystemHeaderPrefixes.size(); I != N; ++I) {
+    AddString(HSOpts.SystemHeaderPrefixes[I].Prefix, Record);
+    Record.push_back(HSOpts.SystemHeaderPrefixes[I].IsSystemHeader);
+  }
+  Stream.EmitRecord(HEADER_SEARCH_PATHS, Record);
+
   // Write out the diagnostic/pragma mappings.
   WritePragmaDiagnosticMappings(Diags, /* isModule = */ WritingModule);
 
@@ -1649,25 +1673,8 @@
   Record.clear();
   const HeaderSearchOptions &HSOpts
     = PP.getHeaderSearchInfo().getHeaderSearchOpts();
-  AddString(HSOpts.Sysroot, Record);
-
-  // Include entries.
-  Record.push_back(HSOpts.UserEntries.size());
-  for (unsigned I = 0, N = HSOpts.UserEntries.size(); I != N; ++I) {
-    const HeaderSearchOptions::Entry &Entry = HSOpts.UserEntries[I];
-    AddString(Entry.Path, Record);
-    Record.push_back(static_cast<unsigned>(Entry.Group));
-    Record.push_back(Entry.IsFramework);
-    Record.push_back(Entry.IgnoreSysRoot);
-  }
-
-  // System header prefixes.
-  Record.push_back(HSOpts.SystemHeaderPrefixes.size());
-  for (unsigned I = 0, N = HSOpts.SystemHeaderPrefixes.size(); I != N; ++I) {
-    AddString(HSOpts.SystemHeaderPrefixes[I].Prefix, Record);
-    Record.push_back(HSOpts.SystemHeaderPrefixes[I].IsSystemHeader);
-  }
 
+  AddString(HSOpts.Sysroot, Record);
   AddString(HSOpts.ResourceDir, Record);
   AddString(HSOpts.ModuleCachePath, Record);
   AddString(HSOpts.ModuleUserBuildPath, Record);