1 /*
   2  * Copyright (c) 2005, 2015, 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  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/shared/collectedHeap.hpp"
  27 #include "gc/shared/gcLocker.hpp"
  28 #include "memory/universe.hpp"
  29 #include "oops/oop.inline.hpp"
  30 #include "runtime/thread.hpp"
  31 #include "runtime/unhandledOops.hpp"
  32 #include "utilities/globalDefinitions.hpp"
  33 
  34 #ifdef CHECK_UNHANDLED_OOPS
  35 const int free_list_size = 256;
  36 
  37 
  38 UnhandledOops::UnhandledOops(Thread* thread) {
  39   _thread = thread;
  40   _oop_list = new (ResourceObj::C_HEAP, mtInternal)
  41                     GrowableArray<UnhandledOopEntry>(free_list_size, true);
  42   _level = 0;
  43 }
  44 
  45 UnhandledOops::~UnhandledOops() {
  46   delete _oop_list;
  47 }
  48 
  49 
  50 void UnhandledOops::dump_oops(UnhandledOops *list) {
  51   for (int k = 0; k < list->_oop_list->length(); k++) {
  52     UnhandledOopEntry entry = list->_oop_list->at(k);
  53     tty->print(" " INTPTR_FORMAT, p2i(entry._oop_ptr));
  54   }
  55   tty->cr();
  56 }
  57 
  58 // For debugging unhandled oop detector _in the debugger_
  59 // You don't want to turn it on in compiled code here.
  60 static bool unhandled_oop_print=0;
  61 
  62 void UnhandledOops::register_unhandled_oop(oop* op, address pc) {
  63   if (!_thread->is_in_stack((address)op))
  64     return;
  65 
  66   _level ++;
  67   if (unhandled_oop_print) {
  68     for (int i=0; i<_level; i++) tty->print(" ");
  69     tty->print_cr("r " INTPTR_FORMAT, p2i(op));
  70   }
  71   UnhandledOopEntry entry(op, pc);
  72   _oop_list->push(entry);
  73 }
  74 
  75 
  76 bool match_oop_entry(void *op, UnhandledOopEntry e) {
  77   return (e.oop_ptr() == op);
  78 }
  79 
  80 // Mark unhandled oop as okay for GC - the containing struct has an oops_do and
  81 // for some reason the oop has to be on the stack.
  82 // May not be called for the current thread, as in the case of
  83 // VM_GetOrSetLocal in jvmti.
  84 void UnhandledOops::allow_unhandled_oop(oop* op) {
  85   assert (CheckUnhandledOops, "should only be called with checking option");
  86 
  87   int i = _oop_list->find_from_end(op, match_oop_entry);
  88   assert(i!=-1, "safe for gc oop not in unhandled_oop_list");
  89 
  90   UnhandledOopEntry entry = _oop_list->at(i);
  91   assert(!entry._ok_for_gc, "duplicate entry");
  92   entry._ok_for_gc = true;
  93   _oop_list->at_put(i, entry);
  94 }
  95 
  96 
  97 // Called by the oop destructor to remove unhandled oop from the thread's
  98 // oop list.  All oops given are assumed to be on the list.  If not,
  99 // there's a bug in the unhandled oop detector.
 100 void UnhandledOops::unregister_unhandled_oop(oop* op) {
 101   if (!_thread->is_in_stack((address)op)) return;
 102 
 103   _level --;
 104   if (unhandled_oop_print) {
 105     for (int i=0; i<_level; i++) tty->print(" ");
 106     tty->print_cr("u " INTPTR_FORMAT, p2i(op));
 107   }
 108 
 109   int i = _oop_list->find_from_end(op, match_oop_entry);
 110   assert(i!=-1, "oop not in unhandled_oop_list");
 111   _oop_list->remove_at(i);
 112 }
 113 
 114 void UnhandledOops::clear_unhandled_oops() {
 115   assert (CheckUnhandledOops, "should only be called with checking option");
 116 
 117   for (int k = 0; k < _oop_list->length(); k++) {
 118     UnhandledOopEntry entry = _oop_list->at(k);
 119     // If an entry is on the unhandled oop list but isn't on the stack
 120     // anymore, it must not have gotten unregistered properly and it's a bug
 121     // in the unhandled oop generator.
 122     if(!_thread->is_in_stack((address)entry._oop_ptr)) {
 123       tty->print_cr("oop_ptr is " INTPTR_FORMAT, p2i(entry._oop_ptr));
 124       tty->print_cr("thread is " INTPTR_FORMAT " from pc " INTPTR_FORMAT,
 125                      p2i(_thread), p2i(entry._pc));
 126       assert(false, "heap is corrupted by the unhandled oop detector");
 127     }
 128     // Set unhandled oops to a pattern that will crash distinctively
 129     if (!entry._ok_for_gc) *(intptr_t*)(entry._oop_ptr) = BAD_OOP_ADDR;
 130   }
 131 }
 132 #endif // CHECK_UNHANDLED_OOPS