src/hotspot/share/oops/instanceRefKlass.cpp

rev 50107 : [mq]: pp2_work

*** 1,7 ****
  /*
!  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 28,41 ****
  #include "oops/instanceRefKlass.inline.hpp"
  #include "oops/oop.inline.hpp"
  
  void InstanceRefKlass::update_nonstatic_oop_maps(Klass* k) {
    // Clear the nonstatic oop-map entries corresponding to referent
!   // and nextPending field.  They are treated specially by the
    // garbage collector.
-   // The discovered field is used only by the garbage collector
-   // and is also treated specially.
    InstanceKlass* ik = InstanceKlass::cast(k);
  
    // Check that we have the right class
    debug_only(static bool first_time = true);
    assert(k == SystemDictionary::Reference_klass() && first_time,
--- 28,39 ----
  #include "oops/instanceRefKlass.inline.hpp"
  #include "oops/oop.inline.hpp"
  
  void InstanceRefKlass::update_nonstatic_oop_maps(Klass* k) {
    // Clear the nonstatic oop-map entries corresponding to referent
!   // and discovered fields.  They are treated specially by the
    // garbage collector.
    InstanceKlass* ik = InstanceKlass::cast(k);
  
    // Check that we have the right class
    debug_only(static bool first_time = true);
    assert(k == SystemDictionary::Reference_klass() && first_time,
*** 43,68 ****
    debug_only(first_time = false);
    assert(ik->nonstatic_oop_map_count() == 1, "just checking");
  
    OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
  
!   // Check that the current map is (2,4) - currently points at field with
!   // offset 2 (words) and has 4 map entries.
!   debug_only(int offset = java_lang_ref_Reference::referent_offset);
!   debug_only(unsigned int count = ((java_lang_ref_Reference::discovered_offset -
!     java_lang_ref_Reference::referent_offset)/heapOopSize) + 1);
  
    if (UseSharedSpaces) {
!     assert(map->offset() == java_lang_ref_Reference::queue_offset &&
!            map->count() == 1, "just checking");
    } else {
!     assert(map->offset() == offset && map->count() == count,
!            "just checking");
! 
!     // Update map to (3,1) - point to offset of 3 (words) with 1 map entry.
!     map->set_offset(java_lang_ref_Reference::queue_offset);
!     map->set_count(1);
    }
  }
  
  
  // Verification
--- 41,77 ----
    debug_only(first_time = false);
    assert(ik->nonstatic_oop_map_count() == 1, "just checking");
  
    OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
  
! #ifdef ASSERT
!   // Verify fields are in the expected places.
!   int referent_offset = java_lang_ref_Reference::referent_offset;
!   int queue_offset = java_lang_ref_Reference::queue_offset;
!   int next_offset = java_lang_ref_Reference::next_offset;
!   int discovered_offset = java_lang_ref_Reference::discovered_offset;
!   assert(referent_offset < queue_offset, "just checking");
!   assert(queue_offset < next_offset, "just checking");
!   assert(next_offset < discovered_offset, "just checking");
!   const unsigned int count =
!     1 + ((discovered_offset - referent_offset) / heapOopSize);
!   assert(count == 4, "just checking");
! #endif // ASSERT
! 
!   // Updated map starts at "queue", covers "queue" and "next".
!   const int new_offset = java_lang_ref_Reference::queue_offset;
!   const unsigned int new_count = 2; // queue and next
  
+   // Verify existing map is as expected, and update if needed.
    if (UseSharedSpaces) {
!     assert(map->offset() == new_offset, "just checking");
!     assert(map->count() == new_count, "just checking");
    } else {
!     assert(map->offset() == referent_offset, "just checking");
!     assert(map->count() == count, "just checking");
!     map->set_offset(new_offset);
!     map->set_count(new_count);
    }
  }
  
  
  // Verification
*** 72,82 ****
    // Verify referent field
    oop referent = java_lang_ref_Reference::referent(obj);
    if (referent != NULL) {
      guarantee(oopDesc::is_oop(referent), "referent field heap failed");
    }
!   // Verify next field
    oop next = java_lang_ref_Reference::next(obj);
    if (next != NULL) {
      guarantee(oopDesc::is_oop(next), "next field should be an oop");
      guarantee(next->is_instance(), "next field should be an instance");
      guarantee(InstanceKlass::cast(next->klass())->is_reference_instance_klass(), "next field verify failed");
--- 81,91 ----
    // Verify referent field
    oop referent = java_lang_ref_Reference::referent(obj);
    if (referent != NULL) {
      guarantee(oopDesc::is_oop(referent), "referent field heap failed");
    }
!   // Additional verification for next field, which must be a Reference or null
    oop next = java_lang_ref_Reference::next(obj);
    if (next != NULL) {
      guarantee(oopDesc::is_oop(next), "next field should be an oop");
      guarantee(next->is_instance(), "next field should be an instance");
      guarantee(InstanceKlass::cast(next->klass())->is_reference_instance_klass(), "next field verify failed");