RFR(S): 8028107: Kitchensink crashed with EAV

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/8028107/webrev/

https://bugs.openjdk.java.net/browse/JDK-8028107

As I explained in previous mail SharedRuntime::resolve_sub_helper() has 
Lock between saving nmethod pointer in local CompiledICInfo variable and 
when it is used to create new compiledIC entry.
Lock may block for safepoint during which nmethod can change state: it 
can be deoptimized or unloaded.
I looked in other places and did not find anything suspicious. For 
example, in handle_ic_miss_helper() compiled entry computation and 
compiledIC setting are done under the same lock.

The fix is to check the state of caller and callee nmethods and skip 
call site patching if any of them is not alive.

Note, we have strange/swapped names for functions which check nmethod state:

   bool  is_in_use() const { return _state == alive; }
   bool  is_alive() const  { return _state == alive || _state == 
not_entrant; }

The dest_entry_point assert in resolve_sub_helper() is mostly useless 
now but I kept it slightly modified.

I was not able to reproduce the problem running kitchensink for 5 days. 
So I can't verify this fix. As I pointed in the bug report this failure 
happens about once per year.

I also fixed indention in nmethod.cpp but webrev does not handle such 
changes. Here they are:

src/share/vm/code/nmethod.cpp
@@ -1660,8 +1660,8 @@
            CompiledICHolder* cichk_oop = ic->cached_icholder();
            if 
(cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
                cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
-              continue;
-            }
+            continue;
+          }
          } else {
            Metadata* ic_oop = ic->cached_metadata();
            if (ic_oop != NULL) {
@@ -1677,8 +1677,8 @@
                ShouldNotReachHere();
              }
            }
-          }
-          ic->set_to_clean();
+        }
+        ic->set_to_clean();
        }
      }
    }

Thanks,
Vladimir