src/share/vm/opto/graphKit.hpp

rev 6132 : 8031755: Type speculation should be used to optimize explicit null checks
Summary: feed profiling data about reference nullness to type speculation.
Reviewed-by:

*** 348,360 ****
    // Helper function to do a NULL pointer check or ZERO check based on type.
    // Throw an exception if a given value is null.
    // Return the value cast to not-null.
    // Be clever about equivalent dominating null checks.
    Node* null_check_common(Node* value, BasicType type,
!                           bool assert_null = false, Node* *null_control = NULL);
    Node* null_check(Node* value, BasicType type = T_OBJECT) {
!     return null_check_common(value, type);
    }
    Node* null_check_receiver() {
      assert(argument(0)->bottom_type()->isa_ptr(), "must be");
      return null_check(argument(0));
    }
--- 348,362 ----
    // Helper function to do a NULL pointer check or ZERO check based on type.
    // Throw an exception if a given value is null.
    // Return the value cast to not-null.
    // Be clever about equivalent dominating null checks.
    Node* null_check_common(Node* value, BasicType type,
!                           bool assert_null = false,
!                           Node* *null_control = NULL,
!                           bool speculative = false);
    Node* null_check(Node* value, BasicType type = T_OBJECT) {
!     return null_check_common(value, type, false, NULL, !_gvn.type(value)->speculative_maybe_null());
    }
    Node* null_check_receiver() {
      assert(argument(0)->bottom_type()->isa_ptr(), "must be");
      return null_check(argument(0));
    }
*** 379,392 ****
    // If never_see_null, use an uncommon trap (*null_control sees a top).
    // The cast is not valid along the null path; keep a copy of the original.
    // If safe_for_replace, then we can replace the value with the cast
    // in the parsing map (the cast is guaranteed to dominate the map)
    Node* null_check_oop(Node* value, Node* *null_control,
!                        bool never_see_null = false, bool safe_for_replace = false);
  
    // Check the null_seen bit.
!   bool seems_never_null(Node* obj, ciProfileData* data);
  
    // Check for unique class for receiver at call
    ciKlass* profile_has_unique_klass() {
      ciCallProfile profile = method()->call_profile_at_bci(bci());
      if (profile.count() >= 0 &&         // no cast failures here
--- 381,396 ----
    // If never_see_null, use an uncommon trap (*null_control sees a top).
    // The cast is not valid along the null path; keep a copy of the original.
    // If safe_for_replace, then we can replace the value with the cast
    // in the parsing map (the cast is guaranteed to dominate the map)
    Node* null_check_oop(Node* value, Node* *null_control,
!                        bool never_see_null = false,
!                        bool safe_for_replace = false,
!                        bool speculative = false);
  
    // Check the null_seen bit.
!   bool seems_never_null(Node* obj, ciProfileData* data, bool& speculating);
  
    // Check for unique class for receiver at call
    ciKlass* profile_has_unique_klass() {
      ciCallProfile profile = method()->call_profile_at_bci(bci());
      if (profile.count() >= 0 &&         // no cast failures here
*** 396,409 ****
      }
      return NULL;
    }
  
    // record type from profiling with the type system
!   Node* record_profile_for_speculation(Node* n, ciKlass* exact_kls);
!   Node* record_profiled_receiver_for_speculation(Node* n);
    void record_profiled_arguments_for_speculation(ciMethod* dest_method, Bytecodes::Code bc);
    void record_profiled_parameters_for_speculation();
  
    // Use the type profile to narrow an object type.
    Node* maybe_cast_profiled_receiver(Node* not_null_obj,
                                       ciKlass* require_klass,
                                       ciKlass* spec,
--- 400,414 ----
      }
      return NULL;
    }
  
    // record type from profiling with the type system
!   Node* record_profile_for_speculation(Node* n, ciKlass* exact_kls, bool maybe_null);
    void record_profiled_arguments_for_speculation(ciMethod* dest_method, Bytecodes::Code bc);
    void record_profiled_parameters_for_speculation();
+   void record_profiled_return_for_speculation();
+   Node* record_profiled_receiver_for_speculation(Node* n);
  
    // Use the type profile to narrow an object type.
    Node* maybe_cast_profiled_receiver(Node* not_null_obj,
                                       ciKlass* require_klass,
                                       ciKlass* spec,