1/*
2 * Copyright (c) 2018, 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 "code/codeCache.hpp"
27#include "code/nmethod.hpp"
28#include "gc/shared/barrierSet.hpp"
29#include "gc/shared/barrierSetNMethod.hpp"
30#include "logging/log.hpp"
31#include "runtime/thread.hpp"
32#include "utilities/debug.hpp"
33
34int BarrierSetNMethod::disarmed_value() const {
35 char* disarmed_addr = reinterpret_cast<char*>(Thread::current());
36 disarmed_addr += in_bytes(thread_disarmed_offset());
37 return *reinterpret_cast<int*>(disarmed_addr);
38}
39
40bool BarrierSetNMethod::supports_entry_barrier(nmethod* nm) {
41 if (nm->method()->is_method_handle_intrinsic()) {
42 return false;
43 }
44
45 if (!nm->is_native_method() && !nm->is_compiled_by_c2() && !nm->is_compiled_by_c1()) {
46 return false;
47 }
48
49 return true;
50}
51
52int BarrierSetNMethod::nmethod_stub_entry_barrier(address* return_address_ptr) {
53 address return_address = *return_address_ptr;
54 CodeBlob* cb = CodeCache::find_blob(return_address);
55 assert(cb != NULL, "invariant");
56
57 nmethod* nm = cb->as_nmethod();
58 BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
59
60 if (!bs_nm->is_armed(nm)) {
61 return 0;
62 }
63
64 assert(!nm->is_osr_method(), "Should not reach here");
65 // Called upon first entry after being armed
66 bool may_enter = bs_nm->nmethod_entry_barrier(nm);
67 if (!may_enter) {
68 log_trace(nmethod, barrier)("Deoptimizing nmethod: " PTR_FORMAT, p2i(nm));
69 bs_nm->deoptimize(nm, return_address_ptr);
70 }
71 return may_enter ? 0 : 1;
72}
73
74bool BarrierSetNMethod::nmethod_osr_entry_barrier(nmethod* nm) {
75 // This check depends on the invariant that all nmethods that are deoptimized / made not entrant
76 // are NOT disarmed.
77 // This invariant is important because a method can be deoptimized after the method have been
78 // resolved / looked up by OSR by another thread. By not deoptimizing them we guarantee that
79 // a deoptimized method will always hit the barrier and come to the same conclusion - deoptimize
80 if (!is_armed(nm)) {
81 return true;
82 }
83
84 assert(nm->is_osr_method(), "Should not reach here");
85 log_trace(nmethod, barrier)("Running osr nmethod entry barrier: " PTR_FORMAT, p2i(nm));
86 return nmethod_entry_barrier(nm);
87}
88