Thu, 07 Apr 2011 09:53:20 -0700
7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes
1 /*
2 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #ifndef SHARE_VM_OOPS_COMPILEDICHOLDERKLASS_HPP
26 #define SHARE_VM_OOPS_COMPILEDICHOLDERKLASS_HPP
28 #include "oops/compiledICHolderOop.hpp"
29 #include "oops/klass.hpp"
30 #include "oops/methodOop.hpp"
32 class CMSIsAliveClosure;
34 // a compiledICHolderKlass is the klass of a compiledICHolderOop
36 class compiledICHolderKlass : public Klass {
37 friend class VMStructs;
38 private:
39 juint _alloc_size; // allocation profiling support
40 public:
41 // Testing
42 bool oop_is_compiledICHolder() const { return true; }
44 // Allocation
45 DEFINE_ALLOCATE_PERMANENT(compiledICHolderKlass);
46 compiledICHolderOop allocate(TRAPS);
47 static klassOop create_klass(TRAPS);
49 // Sizing
50 int oop_size(oop obj) const;
51 int klass_oop_size() const { return object_size(); }
53 // Casting from klassOop
54 static compiledICHolderKlass* cast(klassOop k) {
55 assert(k->klass_part()->oop_is_compiledICHolder(), "cast to compiledICHolderKlass");
56 return (compiledICHolderKlass*) k->klass_part();
57 }
59 // Sizing
60 static int header_size() { return oopDesc::header_size() + sizeof(compiledICHolderKlass)/HeapWordSize; }
61 int object_size() const { return align_object_size(header_size()); }
63 // Garbage collection
64 void oop_follow_contents(oop obj);
65 int oop_adjust_pointers(oop obj);
67 // Parallel Scavenge and Parallel Old
68 PARALLEL_GC_DECLS
70 // Allocation profiling support
71 juint alloc_size() const { return _alloc_size; }
72 void set_alloc_size(juint n) { _alloc_size = n; }
74 // Iterators
75 int oop_oop_iterate(oop obj, OopClosure* blk);
76 int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr);
78 // Printing
79 void oop_print_value_on(oop obj, outputStream* st);
80 void oop_print_on (oop obj, outputStream* st);
82 // Verification
83 const char* internal_name() const;
84 void oop_verify_on(oop obj, outputStream* st);
86 };
88 #endif // SHARE_VM_OOPS_COMPILEDICHOLDERKLASS_HPP