src/hotspot/share/classfile/javaClasses.cpp

rev 54303 : 8221477: Inject os/cpu-specific constants into Unsafe from JVM
Summary: Initialize Unsafe os/cpu-specific constants using injection instead of native callouts
Reviewed-by: duke

*** 3988,3997 ****
--- 3988,4041 ----
  
  int java_lang_System::in_offset_in_bytes() { return static_in_offset; }
  int java_lang_System::out_offset_in_bytes() { return static_out_offset; }
  int java_lang_System::err_offset_in_bytes() { return static_err_offset; }
  
+ // Support for jdk_internal_misc_UnsafeConstants
+ //
+ class UnsafeConstantsFixup : public FieldClosure {
+ private:
+   jint _address_size;
+   jint _page_size;
+   jboolean _big_endian;
+   jboolean _use_unaligned_access;
+ public:
+   UnsafeConstantsFixup(jint address_size, jint page_size, jboolean big_endian, jboolean use_unaligned_access)
+     : _address_size(address_size), _page_size(page_size), _big_endian(big_endian), _use_unaligned_access(use_unaligned_access) {}
+ 
+   void do_field(fieldDescriptor* fd) {
+     if (fd->name() == vmSymbols::address_size_name()) {
+       oop mirror = fd->field_holder()->java_mirror();
+       assert(fd->field_holder() == SystemDictionary::UnsafeConstants_klass(), "Should be UnsafeConstants");
+       assert(mirror != NULL, "UnsafeConstants must have mirror already");
+       mirror->int_field_put(fd->offset(), _address_size);
+     } else if (fd->name() == vmSymbols::page_size_name()) {
+       oop mirror = fd->field_holder()->java_mirror();
+       assert(fd->field_holder() == SystemDictionary::UnsafeConstants_klass(), "Should be UnsafeConstants");
+       assert(mirror != NULL, "UnsafeConstants must have mirror already");
+       mirror->int_field_put(fd->offset(), _page_size);
+     } else if (fd->name() == vmSymbols::big_endian_name()) {
+       oop mirror = fd->field_holder()->java_mirror();
+       assert(fd->field_holder() == SystemDictionary::UnsafeConstants_klass(), "Should be UnsafeConstants");
+       assert(mirror != NULL, "UnsafeConstants must have mirror already");
+       mirror->bool_field_put(fd->offset(), _big_endian);
+     } else if (fd->name() == vmSymbols::use_unaligned_access_name()) {
+       oop mirror = fd->field_holder()->java_mirror();
+       assert(fd->field_holder() == SystemDictionary::UnsafeConstants_klass(), "Should be UnsafeConstants");
+       assert(mirror != NULL, "UnsafeConstants must have mirror already");
+       mirror->bool_field_put(fd->offset(), _use_unaligned_access);
+     }else {
+       assert(false, "unexpected UnsafeConstants field");
+     }
+   }
+ };
+ 
+ void jdk_internal_misc_UnsafeConstants::set_unsafe_constants(jint address_size, jint page_size, jboolean big_endian, jboolean use_unaligned_access) {
+   UnsafeConstantsFixup fix(address_size, page_size, big_endian, use_unaligned_access);
+   InstanceKlass::cast(SystemDictionary::UnsafeConstants_klass())->do_local_static_fields(&fix);
+ }
+ 
  int java_lang_Class::_klass_offset;
  int java_lang_Class::_array_klass_offset;
  int java_lang_Class::_oop_size_offset;
  int java_lang_Class::_static_oop_field_count_offset;
  int java_lang_Class::_class_loader_offset;