diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
index 47d274220a0b..aa84b23fe8b7 100644
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -397,6 +397,14 @@ private:  // Cached tokens state.
   /// allocation.
   MacroInfoChain *MICache;
 
+  struct DeserializedMacroInfoChain {
+    MacroInfo MI;
+    unsigned OwningModuleID; // MUST be immediately after the MacroInfo object
+                     // so it can be accessed by MacroInfo::getOwningModuleID().
+    DeserializedMacroInfoChain *Next;
+  };
+  DeserializedMacroInfoChain *DeserialMIChainHead;
+
 public:
   Preprocessor(IntrusiveRefCntPtr<PreprocessorOptions> PPOpts,
                DiagnosticsEngine &diags, LangOptions &opts,
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 3cd40eacf8ab..50a0cb55f736 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -61,9 +61,12 @@ MacroInfo *Preprocessor::AllocateDeserializedMacroInfo(SourceLocation L,
                                                        unsigned SubModuleID) {
   LLVM_STATIC_ASSERT(llvm::AlignOf<MacroInfo>::Alignment >= sizeof(SubModuleID),
                      "alignment for MacroInfo is less than the ID");
-  MacroInfo *MI =
-      (MacroInfo*)BP.Allocate(sizeof(MacroInfo) + sizeof(SubModuleID),
-                              llvm::AlignOf<MacroInfo>::Alignment);
+  DeserializedMacroInfoChain *MIChain =
+      BP.Allocate<DeserializedMacroInfoChain>();
+  MIChain->Next = DeserialMIChainHead;
+  DeserialMIChainHead = MIChain;
+
+  MacroInfo *MI = &MIChain->MI;
   new (MI) MacroInfo(L);
   MI->FromASTFile = true;
   MI->setOwningModuleID(SubModuleID);
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index 53c45dca01f9..09f827991dc3 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -67,7 +67,8 @@ Preprocessor::Preprocessor(IntrusiveRefCntPtr<PreprocessorOptions> PPOpts,
       CodeComplete(0), CodeCompletionFile(0), CodeCompletionOffset(0),
       CodeCompletionReached(0), SkipMainFilePreamble(0, true), CurPPLexer(0),
       CurDirLookup(0), CurLexerKind(CLK_Lexer), Callbacks(0),
-      MacroArgCache(0), Record(0), MIChainHead(0), MICache(0) {
+      MacroArgCache(0), Record(0), MIChainHead(0), MICache(0),
+      DeserialMIChainHead(0) {
   OwnsHeaderSearch = OwnsHeaders;
   
   ScratchBuf = new ScratchBuffer(SourceMgr);
@@ -153,6 +154,9 @@ Preprocessor::~Preprocessor() {
   for (unsigned i = 0, e = NumCachedTokenLexers; i != e; ++i)
     delete TokenLexerCache[i];
 
+  for (DeserializedMacroInfoChain *I = DeserialMIChainHead ; I ; I = I->Next)
+    I->MI.Destroy();
+
   // Free any cached MacroArgs.
   for (MacroArgs *ArgList = MacroArgCache; ArgList; )
     ArgList = ArgList->deallocate();