src/share/vm/opto/compile.cpp

rev 2164 : [mq]: code-review-comments-tom

*** 627,637 ****
  
      // Put top into the hash table ASAP.
      initial_gvn()->transform_no_reclaim(top());
  
      // Set up tf(), start(), and find a CallGenerator.
!     CallGenerator* cg;
      if (is_osr_compilation()) {
        const TypeTuple *domain = StartOSRNode::osr_domain();
        const TypeTuple *range = TypeTuple::make_range(method()->signature());
        init_tf(TypeFunc::make(domain, range));
        StartNode* s = new (this, 2) StartOSRNode(root(), domain);
--- 627,637 ----
  
      // Put top into the hash table ASAP.
      initial_gvn()->transform_no_reclaim(top());
  
      // Set up tf(), start(), and find a CallGenerator.
!     CallGenerator* cg = NULL;
      if (is_osr_compilation()) {
        const TypeTuple *domain = StartOSRNode::osr_domain();
        const TypeTuple *range = TypeTuple::make_range(method()->signature());
        init_tf(TypeFunc::make(domain, range));
        StartNode* s = new (this, 2) StartOSRNode(root(), domain);
*** 642,655 ****
--- 642,670 ----
        // Normal case.
        init_tf(TypeFunc::make(method()));
        StartNode* s = new (this, 2) StartNode(root(), tf()->domain());
        initial_gvn()->set_type_bottom(s);
        init_start(s);
+       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
+         // With java.lang.ref.reference.get() we must go through the
+         // intrinsic when G1 is enabled - even when get() is the root
+         // method of the compile - so that, if necessary, the value in
+         // the referent field of the reference object gets recorded by
+         // the pre-barrier code.
+         // Specifically, if G1 is enabled, the value in the referent
+         // field is recorded by the G1 SATB pre barrier. This will
+         // result in the referent being marked live and the reference
+         // object removed from the list of discovered references during
+         // reference processing.
+         cg = find_intrinsic(method(), false);
+       }
+       if (cg == NULL) {
          float past_uses = method()->interpreter_invocation_count();
          float expected_uses = past_uses;
          cg = CallGenerator::for_inline(method(), expected_uses);
        }
+     }
      if (failing())  return;
      if (cg == NULL) {
        record_method_not_compilable_all_tiers("cannot parse method");
        return;
      }