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