6619271: The -Xprintflags causes the VM to segv
Summary: add null checks
Reviewed-by: jrose, kvn
/*
* Copyright 2005 Sun Microsystems, Inc. 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.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
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*/
# include "incls/_precompiled.incl"
# include "incls/_unhandledOops.cpp.incl"
#ifdef CHECK_UNHANDLED_OOPS
const int free_list_size = 256;
UnhandledOops::UnhandledOops(Thread* thread) {
_thread = thread;
_oop_list = new (ResourceObj::C_HEAP)
GrowableArray<UnhandledOopEntry>(free_list_size, true);
_level = 0;
}
UnhandledOops::~UnhandledOops() {
delete _oop_list;
}
void UnhandledOops::dump_oops(UnhandledOops *list) {
for (int k = 0; k < list->_oop_list->length(); k++) {
UnhandledOopEntry entry = list->_oop_list->at(k);
tty->print(" " INTPTR_FORMAT, entry._oop_ptr);
}
tty->cr();
}
// For debugging unhandled oop detector _in the debugger_
// You don't want to turn it on in compiled code here.
static bool unhandled_oop_print=0;
void UnhandledOops::register_unhandled_oop(oop* op, address pc) {
if (!_thread->is_in_stack((address)op))
return;
_level ++;
if (unhandled_oop_print) {
for (int i=0; i<_level; i++) tty->print(" ");
tty->print_cr("r " INTPTR_FORMAT, op);
}
UnhandledOopEntry entry(op, pc);
_oop_list->push(entry);
}
bool match_oop_entry(void *op, UnhandledOopEntry e) {
return (e.oop_ptr() == op);
}
// Mark unhandled oop as okay for GC - the containing struct has an oops_do and
// for some reason the oop has to be on the stack.
// May not be called for the current thread, as in the case of
// VM_GetOrSetLocal in jvmti.
void UnhandledOops::allow_unhandled_oop(oop* op) {
assert (CheckUnhandledOops, "should only be called with checking option");
int i = _oop_list->find_at_end(op, match_oop_entry);
assert(i!=-1, "safe for gc oop not in unhandled_oop_list");
UnhandledOopEntry entry = _oop_list->at(i);
assert(!entry._ok_for_gc, "duplicate entry");
entry._ok_for_gc = true;
_oop_list->at_put(i, entry);
}
// Called by the oop destructor to remove unhandled oop from the thread's
// oop list. All oops given are assumed to be on the list. If not,
// there's a bug in the unhandled oop detector.
void UnhandledOops::unregister_unhandled_oop(oop* op) {
if (!_thread->is_in_stack((address)op)) return;
_level --;
if (unhandled_oop_print) {
for (int i=0; i<_level; i++) tty->print(" ");
tty->print_cr("u "INTPTR_FORMAT, op);
}
int i = _oop_list->find_at_end(op, match_oop_entry);
assert(i!=-1, "oop not in unhandled_oop_list");
_oop_list->remove_at(i);
}
void UnhandledOops::clear_unhandled_oops() {
assert (CheckUnhandledOops, "should only be called with checking option");
if (_thread->is_gc_locked_out()) {
return;
}
for (int k = 0; k < _oop_list->length(); k++) {
UnhandledOopEntry entry = _oop_list->at(k);
// If an entry is on the unhandled oop list but isn't on the stack
// anymore, it must not have gotten unregistered properly and it's a bug
// in the unhandled oop generator.
if(!_thread->is_in_stack((address)entry._oop_ptr)) {
tty->print_cr("oop_ptr is " INTPTR_FORMAT, (address)entry._oop_ptr);
tty->print_cr("thread is " INTPTR_FORMAT " from pc " INTPTR_FORMAT,
(address)_thread, (address)entry._pc);
assert(false, "heap is corrupted by the unhandled oop detector");
}
// Set unhandled oops to a pattern that will crash distinctively
if (!entry._ok_for_gc) *(intptr_t*)(entry._oop_ptr) = BAD_OOP_ADDR;
}
}
#endif // CHECK_UNHANDLED_OOPS