src/hotspot/share/classfile/javaClasses.hpp

rev 54472 : 8221836: Avoid recalculating String.hash when zero
Reviewed-by: jrose, adinn
Contributed-by: peter.levart@gmail.com, claes.redestad@oracle.com

@@ -92,10 +92,11 @@
 
 class java_lang_String : AllStatic {
  private:
   static int value_offset;
   static int hash_offset;
+  static int hashIsZero_offset;
   static int coder_offset;
 
   static bool initialized;
 
   static Handle basic_create(int length, bool byte_arr, TRAPS);

@@ -130,23 +131,26 @@
   }
   static int hash_offset_in_bytes()   {
     assert(initialized && (hash_offset > 0), "Must be initialized");
     return hash_offset;
   }
+  static int hashIsZero_offset_in_bytes()   {
+    assert(initialized && (hashIsZero_offset > 0), "Must be initialized");
+    return hashIsZero_offset;
+  }
   static int coder_offset_in_bytes()   {
     assert(initialized && (coder_offset > 0), "Must be initialized");
     return coder_offset;
   }
 
   static inline void set_value_raw(oop string, typeArrayOop buffer);
   static inline void set_value(oop string, typeArrayOop buffer);
-  static inline void set_hash(oop string, unsigned int hash);
 
   // Accessors
   static inline typeArrayOop value(oop java_string);
   static inline typeArrayOop value_no_keepalive(oop java_string);
-  static inline unsigned int hash(oop java_string);
+  static inline bool hash_is_set(oop string);
   static inline bool is_latin1(oop java_string);
   static inline int length(oop java_string);
   static inline int length(oop java_string, typeArrayOop string_value);
   static int utf8_length(oop java_string);
   static int utf8_length(oop java_string, typeArrayOop string_value);