From f7efbb1906e58c3e8eed281c9b8ac7f2224b5ae7 Mon Sep 17 00:00:00 2001
From: Pete Cooper <peter_cooper@apple.com>
Date: Wed, 19 Mar 2014 00:23:30 +0000
Subject: [PATCH] When destroying a StringMap, just iterate over the map and
 destroy the contained elements.  Don't reset them back to 0 as their values
 aren't needed any more.  This results in ~StringMap() being mostly empty for
 POD types in BumpPtrAllocators

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204204 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/ADT/StringMap.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/llvm/ADT/StringMap.h b/include/llvm/ADT/StringMap.h
index c48f1ead023..4e74cf6529e 100644
--- a/include/llvm/ADT/StringMap.h
+++ b/include/llvm/ADT/StringMap.h
@@ -387,7 +387,17 @@ public:
   }
 
   ~StringMap() {
-    clear();
+    // Delete all the elements in the map, but don't reset the elements
+    // to default values.  This is a copy of clear(), but avoids unnecessary
+    // work not required in the destructor.
+    if (!empty()) {
+      for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
+        StringMapEntryBase *Bucket = TheTable[I];
+        if (Bucket && Bucket != getTombstoneVal()) {
+          static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
+        }
+      }
+    }
     free(TheTable);
   }
 };