Prevent multiple threads to populate the keyword table

diff --git a/mcs/class/System/Microsoft.CSharp/CSharpCodeGenerator.cs b/mcs/class/System/Microsoft.CSharp/CSharpCodeGenerator.cs
index e5d9e5e7e669b6fa293eed9d2037467b419084eb..0f8322efc76c4d28f3d0d3573a5448059b630a1e 100644 (file)
--- a/mcs/class/System/Microsoft.CSharp/CSharpCodeGenerator.cs
+++ b/mcs/class/System/Microsoft.CSharp/CSharpCodeGenerator.cs
@@ -1597,9 +1597,13 @@ namespace Mono.CSharp
 
                static void FillKeywordTable ()
                {
-                       keywordsTable = new Hashtable ();
-                       foreach (string keyword in keywords) {
-                               keywordsTable.Add (keyword, keyword);
+                       lock (keywords) {
+                               if (keywordsTable == null) {
+                                       keywordsTable = new Hashtable ();
+                                       foreach (string keyword in keywords) {
+                                               keywordsTable.Add (keyword, keyword);
+                                       }
+                               }
                        }
                }