PTH:
Use an array instead of a DenseMap to cache persistent IDs -> IdentifierInfo*.  This leads to a 4% speedup at -fsyntax-only using PTH.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@60452 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Driver/CacheTokens.cpp b/Driver/CacheTokens.cpp
index 536fefc..7904954 100644
--- a/Driver/CacheTokens.cpp
+++ b/Driver/CacheTokens.cpp
@@ -104,7 +104,7 @@
   }
   
   Offset DataOff = Out.tell();
-  
+    
   for (InverseIDMap::iterator I=IIDMap.begin(), E=IIDMap.end(); I!=E; ++I) {
     // Record the location for this data.
     I->FileOffset = Out.tell();
@@ -118,6 +118,9 @@
   // Now emit the table mapping from persistent IDs to PTH file offsets.  
   Offset IDOff = Out.tell();
   
+  // Emit the number of identifiers.
+  Emit32(Out, max);
+
   for (InverseIDMap::iterator I=IIDMap.begin(), E=IIDMap.end(); I!=E; ++I)
     Emit32(Out, I->FileOffset);