EVALUATION

http://hg.openjdk.java.net/jdk7/build/hotspot/rev/a4c7fe54bf3f
                                     

EVALUATION

http://hg.openjdk.java.net/jdk7/hotspot-rt/hotspot/rev/a4c7fe54bf3f
                                     

EVALUATION

The prolem seems to be in handling of switch padding in relocator.cpp. Relocator::handle_switch_pad()
moves the expanded instruction up, but the code does not clear the new padding area. This will throw 
(under the right circumstances) java.lang.VeryError in post merge-CP classfile verification in 
RedefineClasses code.
                                     

WORK AROUND

If the verification is disabled using -Xverify:none, everything works fine.
                                     

SUGGESTED FIX

The fix is very simple. The new switch padding area has to be cleared to satisfy the classfile verification.

diff --git a/src/share/vm/runtime/relocator.cpp b/src/share/vm/runtime/relocator.cpp
--- a/src/share/vm/runtime/relocator.cpp
+++ b/src/share/vm/runtime/relocator.cpp
@@ -641,6 +641,8 @@
       memmove(addr_at(bci +1 + new_pad),
               addr_at(bci +1 + old_pad),
               len * 4);
+      // clean the padding area; it will make verifier happy
+      memset(addr_at(bci +1), 0, new_pad);
     }
   }
   return true;