8343800: Cleanup definition of NULL_WORD

Reviewed-by: dholmes, kvn

Author: Kim Barrett

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -560,6 +560,9 @@ const jfloat min_jfloat = jfloat_cast(min_jintFloat);
 const jint max_jintFloat = (jint)(0x7f7fffff);
 const jfloat max_jfloat = jfloat_cast(max_jintFloat);
 
+// A named constant for the integral representation of a Java null.
+const intptr_t NULL_WORD = 0;
+
 //----------------------------------------------------------------------------------------------------
 // JVM spec restrictions
 

src/hotspot/share/utilities/globalDefinitions_gcc.hpp

@@ -71,24 +71,6 @@
 #include <sys/time.h>
 #endif // LINUX || _ALLBSD_SOURCE
 
-// NULL vs NULL_WORD:
-// On Linux NULL is defined as a special type '__null'. Assigning __null to
-// integer variable will cause gcc warning. Use NULL_WORD in places where a
-// pointer is stored as integer value.  On some platforms, sizeof(intptr_t) >
-// sizeof(void*), so here we want something which is integer type, but has the
-// same size as a pointer.
-#ifdef __GNUC__
-  #ifdef _LP64
-    #define NULL_WORD  0L
-  #else
-    // Cast 0 to intptr_t rather than int32_t since they are not the same type
-    // on platforms such as Mac OS X.
-    #define NULL_WORD  ((intptr_t)0)
-  #endif
-#else
-  #define NULL_WORD  NULL
-#endif
-
 // checking for nanness
 #if defined(__APPLE__)
 inline int g_isnan(double f) { return isnan(f); }

src/hotspot/share/utilities/globalDefinitions_visCPP.hpp

@@ -72,12 +72,6 @@
 // 64-bit integer-suffix (LL) instead.
 #define NULL 0LL
 
-// NULL vs NULL_WORD:
-// On Linux NULL is defined as a special type '__null'. Assigning __null to
-// integer variable will cause gcc warning. Use NULL_WORD in places where a
-// pointer is stored as integer value.
-#define NULL_WORD NULL
-
 typedef int64_t ssize_t;
 
 // Non-standard stdlib-like stuff: