src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

rev 5918 : 8035326: Assume non-NULL references in G1CollectedHeap::in_cset_fast_test
Summary: Remove the assumption that G1CollectedHeap::in_cset_fast_test needs to check for NULL references. Most of the time this is not required, making the code doing this check multiple times.
Reviewed-by:

*** 696,722 ****
      assert(!_in_cset_fast_test_base[index], "invariant");
      _in_cset_fast_test_base[index] = true;
    }
  
    // This is a fast test on whether a reference points into the
!   // collection set or not. It does not assume that the reference
!   // points into the heap; if it doesn't, it will return false.
    bool in_cset_fast_test(oop obj) {
      assert(_in_cset_fast_test != NULL, "sanity");
!     if (_g1_committed.contains((HeapWord*) obj)) {
        // no need to subtract the bottom of the heap from obj,
        // _in_cset_fast_test is biased
        uintx index = cast_from_oop<uintx>(obj) >> HeapRegion::LogOfHRGrainBytes;
        bool ret = _in_cset_fast_test[index];
        // let's make sure the result is consistent with what the slower
        // test returns
        assert( ret || !obj_in_cs(obj), "sanity");
        assert(!ret ||  obj_in_cs(obj), "sanity");
        return ret;
-     } else {
-       return false;
-     }
    }
  
    void clear_cset_fast_test() {
      assert(_in_cset_fast_test_base != NULL, "sanity");
      memset(_in_cset_fast_test_base, false,
--- 696,719 ----
      assert(!_in_cset_fast_test_base[index], "invariant");
      _in_cset_fast_test_base[index] = true;
    }
  
    // This is a fast test on whether a reference points into the
!   // collection set or not. Assume that the reference
!   // points into the heap.
    bool in_cset_fast_test(oop obj) {
      assert(_in_cset_fast_test != NULL, "sanity");
!     assert(_g1_committed.contains((HeapWord*) obj), "");
      // no need to subtract the bottom of the heap from obj,
      // _in_cset_fast_test is biased
      uintx index = cast_from_oop<uintx>(obj) >> HeapRegion::LogOfHRGrainBytes;
      bool ret = _in_cset_fast_test[index];
      // let's make sure the result is consistent with what the slower
      // test returns
      assert( ret || !obj_in_cs(obj), "sanity");
      assert(!ret ||  obj_in_cs(obj), "sanity");
      return ret;
    }
  
    void clear_cset_fast_test() {
      assert(_in_cset_fast_test_base != NULL, "sanity");
      memset(_in_cset_fast_test_base, false,