Add templated field_addr implementation

Author: tkrodriguez

src/hotspot/share/jvmci/jvmciCompilerToVM.cpp

@@ -2097,14 +2097,14 @@ static jobject read_field_value(Handle obj, long displacement, jchar type_char,
   // folding Unsafe.get* methods with volatile semantics.
 
   switch (basic_type) {
-    case T_BOOLEAN: value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr<jboolean>(displacement)); break;
-    case T_BYTE:    value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr<jbyte>(displacement));    break;
-    case T_SHORT:   value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr<jshort>(displacement));   break;
-    case T_CHAR:    value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr<jchar>(displacement));    break;
+    case T_BOOLEAN: value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr_of_type<jboolean>(displacement)); break;
+    case T_BYTE:    value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr_of_type<jbyte>(displacement));    break;
+    case T_SHORT:   value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr_of_type<jshort>(displacement));   break;
+    case T_CHAR:    value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr_of_type<jchar>(displacement));    break;
     case T_FLOAT:
-    case T_INT:     value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr<jint>(displacement));     break;
+    case T_INT:     value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr_of_type<jint>(displacement));     break;
     case T_DOUBLE:
-    case T_LONG:    value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr<jlong>(displacement));    break;
+    case T_LONG:    value = HeapAccess<MO_SEQ_CST>::load(obj->field_addr_of_type<jlong>(displacement));    break;
 
     case T_OBJECT: {
       if (displacement == java_lang_Class::component_mirror_offset() && java_lang_Class::is_instance(obj()) &&

src/hotspot/share/oops/oop.hpp

@@ -117,6 +117,10 @@ class oopDesc {
   // field addresses in oop
   inline void* field_addr(int offset) const;
 
+  // Backport of templating version of field_addr
+  template<typename T>
+  inline T* field_addr_of_type(int offset) const;
+
   // Need this as public for garbage collection.
   template <class T> inline T* obj_field_addr(int offset) const;
 

src/hotspot/share/oops/oop.inline.hpp

@@ -211,6 +211,9 @@ void*    oopDesc::field_addr(int offset)     const { return reinterpret_cast<voi
 template <class T>
 T*       oopDesc::obj_field_addr(int offset) const { return (T*) field_addr(offset); }
 
+template<typename T>
+T*       oopDesc::field_addr_of_type(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
+
 template <typename T>
 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }