src/hotspot/share/gc/shenandoah/shenandoahSharedVariables.hpp

*** 119,18 ***
    void set(uint mask) {
      assert (mask < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");
      ShenandoahSharedValue mask_val = (ShenandoahSharedValue) mask;
      while (true) {
        ShenandoahSharedValue ov = Atomic::load_acquire(&value);
!       if ((ov & mask_val) != 0) {
          // already set
          return;
        }
  
        ShenandoahSharedValue nv = ov | mask_val;
        if (Atomic::cmpxchg(&value, ov, nv) == ov) {
!         // successfully set
          return;
        }
      }
    }
  
--- 119,19 ---
    void set(uint mask) {
      assert (mask < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");
      ShenandoahSharedValue mask_val = (ShenandoahSharedValue) mask;
      while (true) {
        ShenandoahSharedValue ov = Atomic::load_acquire(&value);
!       // We require all bits of mask_val to be set
+       if ((ov & mask_val) == mask_val) {
          // already set
          return;
        }
  
        ShenandoahSharedValue nv = ov | mask_val;
        if (Atomic::cmpxchg(&value, ov, nv) == ov) {
!         // successfully set: if value returned from cmpxchg equals ov, then nv has overwritten value.
          return;
        }
      }
    }
  

*** 154,14 ***
--- 155,23 ---
  
    void clear() {
      Atomic::release_store_fence(&value, (ShenandoahSharedValue)0);
    }
  
+   // Returns true iff any bit set in mask is set in this.value.
    bool is_set(uint mask) const {
      return !is_unset(mask);
    }
  
+   // Returns true iff all bits set in mask are set in this.value.
+   bool is_set_exactly(uint mask) const {
+     assert (mask < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");
+     uint uvalue = Atomic::load_acquire(&value);
+     return (uvalue & mask) == mask;
+   }
+ 
+   // Returns true iff all bits set in mask are unset in this.value.
    bool is_unset(uint mask) const {
      assert (mask < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");
      return (Atomic::load_acquire(&value) & (ShenandoahSharedValue) mask) == 0;
    }