8346714: [ASAN] compressedKlass.cpp reported applying non-zero offset to null pointer

Reviewed-by: mdoerr, coleenp

Author: SendaoYan

src/hotspot/share/oops/compressedKlass.cpp

@@ -96,7 +96,7 @@ void CompressedKlassPointers::sanity_check_after_initialization() {
 
   // Check that Klass range is fully engulfed in the encoding range
   const address encoding_start = _base;
-  const address encoding_end = _base + nth_bit(narrow_klass_pointer_bits() + _shift);
+  const address encoding_end = (address)(p2u(_base) + (uintptr_t)nth_bit(narrow_klass_pointer_bits() + _shift));
   ASSERT_HERE_2(_klass_range_start >= _base && _klass_range_end <= encoding_end,
                 "Resulting encoding range does not fully cover the class range");
 

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -185,6 +185,11 @@ inline intptr_t p2i(const volatile void* p) {
   return (intptr_t) p;
 }
 
+// Convert pointer to uintptr_t
+inline uintptr_t p2u(const volatile void* p) {
+  return (uintptr_t) p;
+}
+
 #define BOOL_TO_STR(_b_) ((_b_) ? "true" : "false")
 
 //----------------------------------------------------------------------------------------------------