Re: RFR (S) 8013942: JSR 292: assert(type() == T_OBJECT) failed: type check

[Vladimir Ivanov]

Looks good.

Best regards,
Vladimir Ivanov

On 6/25/14 5:57 PM, serguei.spit...@oracle.com wrote:

Please, review the fix for:
   https://bugs.openjdk.java.net/browse/JDK-8013942


Open webrev:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2014/hotspot/8013942-JVMTI-lobj.1



Summary:

   This is a Nightly Stabilization issue.

   The problem is that the JVMTI GetLocalObject() function is hitting
the assert
   as the type of the local at current bci is not T_OBJECT as expected.
   It is because this local is alive only in a narrow scope of one
condition in the method but current bci is out of this csope.

   A fragment from the target method:

     static Class<?> canonicalize(Class<?> t, int how) {
         Class<?> ct;                                 <== The local
         if (t == Object.class) {
             // no change, ever
         } else if (!t.isPrimitive()) {
             switch (how) {
                 case UNWRAP:
                     ct = Wrapper.asPrimitiveType(t); <== Initialized here
                     if (ct != t) return ct;
                     break;
                 case RAW_RETURN:
                 case ERASE:
                     return Object.class;
             }
         } else if (t == void.class) {                <== The
GetLocalObject() is called with bci in this block
             // no change, usually
             switch (how) {
                 case RAW_RETURN:
                     return int.class;
                 case WRAP:
                     return Void.class;
             }
         } else {
         . . .

   The local 'ct' is only alive in the block of condition "if
(!t.isPrimitive())".
   However, it is dead local in the next block.

   The fix suggested in the webrev above is to use the oop_mask for the
method's current bci.
   It tells when the local is dead in the scope of this bci.
   Return the JVMTI_ERROR_INVALID_SLOT error in such a case.

   The fix also includes the tweeks which are necessary to enable the
InterpreterOopMap.is_dead()
   function in the product mode as it was originally defined only under
"#ifdef ENABLE_ZAP_DEAD_LOCALS".
   This makes the code in the oopMapCache.?pp a little bit more simple.


Testing:
   Running the failing tests: vm.mlvm.indy.func.jvmti
   In progress: nsk.jvmti, nsk.jdi, nsk.jdwp test runs on sparcv9 and amd64


Thanks,
Serguei