src/hotspot/share/cds/aotClassInitializer.cpp

@@ -24,15 +24,21 @@
  
  #include "precompiled.hpp"
  #include "cds/aotClassInitializer.hpp"
  #include "cds/archiveBuilder.hpp"
  #include "cds/cdsConfig.hpp"
+ #include "dumpTimeClassInfo.inline.hpp"
  #include "cds/heapShared.hpp"
+ #include "classfile/systemDictionaryShared.hpp"
  #include "classfile/vmSymbols.hpp"
+ #include "memory/resourceArea.hpp"
+ #include "oops/fieldStreams.inline.hpp"
  #include "oops/instanceKlass.inline.hpp"
  #include "oops/symbol.hpp"
+ #include "runtime/fieldDescriptor.inline.hpp"
  #include "runtime/javaCalls.hpp"
+ #include "runtime/mutexLocker.hpp"
  
  // Detector for class names we wish to handle specially.
  // It is either an exact string match or a string prefix match.
  class AOTClassInitializer::AllowedSpec {
    const char* _class_name;

@@ -355,5 +361,129 @@
        AOTLinkedClassBulkLoader::exit_on_exception(current);
      }
    }
  }
  
+ // check_can_be_preinited() is quite costly, so we cache the results inside
+ // DumpTimeClassInfo::_can_be_preinited. See also AOTClassInitializer::reset_preinit_check().
+ bool AOTClassInitializer::check_can_be_preinited(InstanceKlass* ik) {
+   ResourceMark rm;
+ 
+   if (!SystemDictionaryShared::is_builtin(ik)) {
+     log_info(cds, init)("cannot initialize %s (not built-in loader)", ik->external_name());
+     return false;
+   }
+ 
+   InstanceKlass* super = ik->java_super();
+   if (super != nullptr && !can_be_preinited_locked(super)) {
+     log_info(cds, init)("cannot initialize %s (super %s not initable)", ik->external_name(), super->external_name());
+     return false;
+   }
+ 
+   Array<InstanceKlass*>* interfaces = ik->local_interfaces();
+   for (int i = 0; i < interfaces->length(); i++) {
+     if (!can_be_preinited_locked(interfaces->at(i))) {
+       log_info(cds, init)("cannot initialize %s (interface %s not initable)",
+                           ik->external_name(), interfaces->at(i)->external_name());
+       return false;
+     }
+   }
+ 
+   if (HeapShared::is_lambda_form_klass(ik)) {
+     // We allow only these to have <clinit> or non-default static fields
+     return true;
+   }
+ 
+   if (ik->class_initializer() != nullptr) {
+     log_info(cds, init)("cannot initialize %s (has <clinit>)", ik->external_name());
+     return false;
+   }
+   if (ik->is_initialized() && !has_default_static_fields(ik)) {
+     return false;
+   }
+ 
+   return true;
+ }
+ 
+ bool AOTClassInitializer::has_default_static_fields(InstanceKlass* ik) {
+   oop mirror = ik->java_mirror();
+ 
+   for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
+     if (fs.access_flags().is_static()) {
+       fieldDescriptor& fd = fs.field_descriptor();
+       int offset = fd.offset();
+       bool is_default = true;
+       bool has_initval = fd.has_initial_value();
+       switch (fd.field_type()) {
+       case T_OBJECT:
+       case T_ARRAY:
+         is_default = mirror->obj_field(offset) == nullptr;
+         break;
+       case T_BOOLEAN:
+         is_default = mirror->bool_field(offset) == (has_initval ? fd.int_initial_value() : 0);
+         break;
+       case T_BYTE:
+         is_default = mirror->byte_field(offset) == (has_initval ? fd.int_initial_value() : 0);
+         break;
+       case T_SHORT:
+         is_default = mirror->short_field(offset) == (has_initval ? fd.int_initial_value() : 0);
+         break;
+       case T_CHAR:
+         is_default = mirror->char_field(offset) == (has_initval ? fd.int_initial_value() : 0);
+         break;
+       case T_INT:
+         is_default = mirror->int_field(offset) == (has_initval ? fd.int_initial_value() : 0);
+         break;
+       case T_LONG:
+         is_default = mirror->long_field(offset) == (has_initval ? fd.long_initial_value() : 0);
+         break;
+       case T_FLOAT:
+         is_default = mirror->float_field(offset) == (has_initval ? fd.float_initial_value() : 0);
+         break;
+       case T_DOUBLE:
+         is_default = mirror->double_field(offset) == (has_initval ? fd.double_initial_value() : 0);
+         break;
+       default:
+         ShouldNotReachHere();
+       }
+ 
+       if (!is_default) {
+         log_info(cds, init)("cannot initialize %s (static field %s has non-default value)",
+                             ik->external_name(), fd.name()->as_C_string());
+         return false;
+       }
+     }
+   }
+ 
+   return true;
+ }
+ 
+ bool AOTClassInitializer::can_be_preinited(InstanceKlass* ik) {
+   MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
+   return can_be_preinited_locked(ik);
+ }
+ 
+ bool AOTClassInitializer::can_be_preinited_locked(InstanceKlass* ik) {
+   if (!CDSConfig::is_initing_classes_at_dump_time()) {
+     return false;
+   }
+ 
+   assert_lock_strong(DumpTimeTable_lock);
+   DumpTimeClassInfo* info = SystemDictionaryShared::get_info_locked(ik);
+   if (!info->has_done_preinit_check()) {
+     info->set_can_be_preinited(AOTClassInitializer::check_can_be_preinited(ik));
+   }
+   return info->can_be_preinited();
+ }
+ 
+ // Initialize a class at dump time, if possible.
+ void AOTClassInitializer::maybe_preinit_class(InstanceKlass* ik, TRAPS) {
+ #if 0 // FIXME -- leyden+JEP483 merge
+   if (!ik->is_initialized() && AOTClassInitializer::can_be_preinited(ik)) {
+     if (log_is_enabled(Info, cds, init)) {
+       ResourceMark rm;
+       log_info(cds, init)("preinitializing %s", ik->external_name());
+     }
+     ik->initialize(CHECK);
+   }
+ #endif
+ }