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
duke@435 | 1 | /* |
stefank@2314 | 2 | * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #ifndef CPU_SPARC_VM_C1_LINEARSCAN_SPARC_HPP |
stefank@2314 | 26 | #define CPU_SPARC_VM_C1_LINEARSCAN_SPARC_HPP |
stefank@2314 | 27 | |
duke@435 | 28 | inline bool LinearScan::is_processed_reg_num(int reg_num) { |
duke@435 | 29 | return reg_num < 26 || reg_num > 31; |
duke@435 | 30 | } |
duke@435 | 31 | |
duke@435 | 32 | inline int LinearScan::num_physical_regs(BasicType type) { |
duke@435 | 33 | // Sparc requires two cpu registers for long |
duke@435 | 34 | // and two cpu registers for double |
duke@435 | 35 | #ifdef _LP64 |
duke@435 | 36 | if (type == T_DOUBLE) { |
duke@435 | 37 | #else |
duke@435 | 38 | if (type == T_DOUBLE || type == T_LONG) { |
duke@435 | 39 | #endif |
duke@435 | 40 | return 2; |
duke@435 | 41 | } |
duke@435 | 42 | return 1; |
duke@435 | 43 | } |
duke@435 | 44 | |
duke@435 | 45 | |
duke@435 | 46 | inline bool LinearScan::requires_adjacent_regs(BasicType type) { |
duke@435 | 47 | #ifdef _LP64 |
duke@435 | 48 | return type == T_DOUBLE; |
duke@435 | 49 | #else |
duke@435 | 50 | return type == T_DOUBLE || type == T_LONG; |
duke@435 | 51 | #endif |
duke@435 | 52 | } |
duke@435 | 53 | |
duke@435 | 54 | inline bool LinearScan::is_caller_save(int assigned_reg) { |
duke@435 | 55 | return assigned_reg > pd_last_callee_saved_reg && assigned_reg <= pd_last_fpu_reg; |
duke@435 | 56 | } |
duke@435 | 57 | |
duke@435 | 58 | |
duke@435 | 59 | inline void LinearScan::pd_add_temps(LIR_Op* op) { |
duke@435 | 60 | // No special case behaviours yet |
duke@435 | 61 | } |
duke@435 | 62 | |
duke@435 | 63 | |
duke@435 | 64 | inline bool LinearScanWalker::pd_init_regs_for_alloc(Interval* cur) { |
duke@435 | 65 | if (allocator()->gen()->is_vreg_flag_set(cur->reg_num(), LIRGenerator::callee_saved)) { |
duke@435 | 66 | assert(cur->type() != T_FLOAT && cur->type() != T_DOUBLE, "cpu regs only"); |
duke@435 | 67 | _first_reg = pd_first_callee_saved_reg; |
duke@435 | 68 | _last_reg = pd_last_callee_saved_reg; |
duke@435 | 69 | return true; |
roland@2206 | 70 | } else if (cur->type() == T_INT || cur->type() == T_LONG || cur->type() == T_OBJECT || cur->type() == T_ADDRESS) { |
duke@435 | 71 | _first_reg = pd_first_cpu_reg; |
duke@435 | 72 | _last_reg = pd_last_allocatable_cpu_reg; |
duke@435 | 73 | return true; |
duke@435 | 74 | } |
duke@435 | 75 | return false; |
duke@435 | 76 | } |
stefank@2314 | 77 | |
stefank@2314 | 78 | #endif // CPU_SPARC_VM_C1_LINEARSCAN_SPARC_HPP |