VM: Fix memory leak during shutdown

runtime/platform/hashmap.cc

Index: runtime/platform/hashmap.cc
diff --git a/runtime/platform/hashmap.cc b/runtime/platform/hashmap.cc
index 461153398129a270433f45682ffd8f0765885a91..4d4b4774dd362a8e3c866f00c49c9abb6de84678 100644
--- a/runtime/platform/hashmap.cc
+++ b/runtime/platform/hashmap.cc
@@ -106,11 +106,27 @@ void HashMap::Remove(void* key, uint32_t hash) {
 
   // Clear the candidate which will not break searching the hash table.
   candidate->key = NULL;
-  candidate->value = NULL;
   occupancy_--;
 }
 
 
+HashMap::Entry* HashMap::Remove(Entry* entry) {
+  Remove(entry->key, entry->hash);
+
+  // A key can only exist once in the map and we just removed `key`. This means
+  // that either a left-rotation has happened (in which case `entry` points
+  // already to the next element (in terms of iteration order)) or alternatively
+  // we can use the normal `Next()` call to move in iteration order.
+  if (entry->key != NULL) {
+    // A left-rotation happened. `entry` points already to the next element in
+    // iteration order.
+    return entry;
+  } else {
+    return Next(entry);
+  }
+}
+
+
 void HashMap::Clear(ClearFun clear) {
   // Mark all entries as empty.
   const Entry* end = map_end();
@@ -118,7 +134,6 @@ void HashMap::Clear(ClearFun clear) {
     if ((clear != NULL) && (p->key != NULL)) {
       clear(p->value);
     }
-    p->value = NULL;
     p->key = NULL;
   }
   occupancy_ = 0;