Update CmpDriver to report missing commands.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62728 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/CmpDriver b/utils/CmpDriver
index cc4caad..5420984 100755
--- a/utils/CmpDriver
+++ b/utils/CmpDriver
@@ -152,7 +152,16 @@
         differ = True
 
     # Compare commands.
-    for i,(a,b) in enumerate(zip(infoA.commands, infoB.commands)):
+    for i,(a,b) in enumerate(map(None, infoA.commands, infoB.commands)):
+        if a is None:
+            print 'A MISSING:',' '.join(b)
+            differ = True
+            continue
+        elif b is None:
+            print 'B MISSING:',' '.join(a)
+            differ = True
+            continue
+
         diff = DriverZipperDiff(a,b)
         diffs = list(diff.getDiffs())
         if diffs:
@@ -169,7 +178,7 @@
                     print 'mismatch: A: %s' % aElt
                     print '          B: %s' % bElt
             differ = True
-
+    
     # Compare result codes.
     if infoA.exitCode != infoB.exitCode:
         print '-- EXIT CODES DIFFER -'