1 /*
  2  * Copyright (c) 2019, 2021, Red Hat, Inc. 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 
 26 #include "precompiled.hpp"
 27 
 28 
 29 #include "classfile/classLoaderDataGraph.hpp"
 30 #include "code/codeCache.hpp"
 31 #include "gc/shenandoah/shenandoahAsserts.hpp"
 32 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 33 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
 34 #include "gc/shenandoah/shenandoahRootVerifier.hpp"
 35 #include "gc/shenandoah/shenandoahScanRemembered.inline.hpp"
 36 #include "gc/shenandoah/shenandoahStringDedup.hpp"
 37 #include "gc/shenandoah/shenandoahUtils.hpp"
 38 #include "gc/shared/oopStorage.inline.hpp"
 39 #include "gc/shared/oopStorageSet.hpp"
 40 #include "runtime/jniHandles.hpp"
 41 #include "runtime/thread.hpp"
 42 #include "utilities/debug.hpp"
 43 #include "utilities/enumIterator.hpp"
 44 
 45 ShenandoahGCStateResetter::ShenandoahGCStateResetter() :
 46   _heap(ShenandoahHeap::heap()),
 47   _gc_state(_heap->gc_state()) {
 48   _heap->_gc_state.clear();
 49 }
 50 
 51 ShenandoahGCStateResetter::~ShenandoahGCStateResetter() {
 52   _heap->_gc_state.set(_gc_state);
 53   assert(_heap->gc_state() == _gc_state, "Should be restored");
 54 }
 55 
 56 void ShenandoahRootVerifier::roots_do(OopIterateClosure* oops) {
 57   ShenandoahGCStateResetter resetter;
 58   shenandoah_assert_safepoint();
 59 
 60   CodeBlobToOopClosure blobs(oops, !CodeBlobToOopClosure::FixRelocations);
 61   CodeCache::blobs_do(&blobs);
 62 
 63   CLDToOopClosure clds(oops, ClassLoaderData::_claim_none);
 64   ClassLoaderDataGraph::cld_do(&clds);
 65 
 66   for (auto id : EnumRange<OopStorageSet::StrongId>()) {
 67     OopStorageSet::storage(id)->oops_do(oops);
 68   }
 69 
 70   ShenandoahHeap* heap = ShenandoahHeap::heap();
 71   if (heap->mode()->is_generational() && heap->is_gc_generation_young()) {
 72     shenandoah_assert_safepoint();
 73     heap->card_scan()->roots_do(oops);
 74   }
 75 
 76   // Do thread roots the last. This allows verification code to find
 77   // any broken objects from those special roots first, not the accidental
 78   // dangling reference from the thread root.
 79   Threads::possibly_parallel_oops_do(true, oops, NULL);
 80 }
 81 
 82 void ShenandoahRootVerifier::strong_roots_do(OopIterateClosure* oops) {
 83   ShenandoahGCStateResetter resetter;
 84   shenandoah_assert_safepoint();
 85 
 86   CLDToOopClosure clds(oops, ClassLoaderData::_claim_none);
 87   ClassLoaderDataGraph::always_strong_cld_do(&clds);
 88 
 89   for (auto id : EnumRange<OopStorageSet::StrongId>()) {
 90     OopStorageSet::storage(id)->oops_do(oops);
 91   }
 92 
 93   ShenandoahHeap* heap = ShenandoahHeap::heap();
 94   if (heap->mode()->is_generational() && heap->is_gc_generation_young()) {
 95     heap->card_scan()->roots_do(oops);
 96   }
 97 
 98   // Do thread roots the last. This allows verification code to find
 99   // any broken objects from those special roots first, not the accidental
100   // dangling reference from the thread root.
101   CodeBlobToOopClosure blobs(oops, !CodeBlobToOopClosure::FixRelocations);
102   Threads::possibly_parallel_oops_do(true, oops, &blobs);
103 }