/*

 * Copyright (c) 2017, 2018, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include "precompiled.hpp"

#include "gc/g1/g1BlockOffsetTable.hpp"

#include "gc/g1/g1CollectedHeap.hpp"

#include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"

#include "gc/g1/heapRegion.inline.hpp"

#include "gc/shared/referenceProcessor.hpp"

#include "runtime/interfaceSupport.inline.hpp"

#include "runtime/vmThread.hpp"

#include "unittest.hpp"

class VerifyAndCountMarkClosure : public StackObj {

  int _count;

  G1CMBitMap* _bm;

  void ensure_marked(HeapWord* addr) {

    ASSERT_TRUE(_bm->is_marked(addr));

  }

public:

  VerifyAndCountMarkClosure(G1CMBitMap* bm) : _count(0), _bm(bm) { }

  virtual size_t apply(oop object) {

    _count++;

    ensure_marked((HeapWord*) object);

    // Must return positive size to advance the iteration.

    return MinObjAlignment;

  }

  void reset() {

    _count = 0;

  }

  int count() {

    return _count;

  }

};

#define MARK_OFFSET_1 ( 17 * MinObjAlignment)

#define MARK_OFFSET_2 ( 99 * MinObjAlignment)

#define MARK_OFFSET_3 (337 * MinObjAlignment)

class VM_HeapRegionApplyToMarkedObjectsTest : public VM_GTestExecuteAtSafepoint {

public:

  void doit();

};

void VM_HeapRegionApplyToMarkedObjectsTest::doit() {

  G1CollectedHeap* heap = G1CollectedHeap::heap();

  // Using region 0 for testing.

  HeapRegion* region = heap->heap_region_containing(heap->bottom_addr_for_region(0));

  // Mark some "oops" in the bitmap.

  G1CMBitMap* bitmap = heap->concurrent_mark()->next_mark_bitmap();

  bitmap->mark(region->bottom());

  bitmap->mark(region->bottom() + MARK_OFFSET_1);

  bitmap->mark(region->bottom() + MARK_OFFSET_2);

  bitmap->mark(region->bottom() + MARK_OFFSET_3);

  bitmap->mark(region->end());

  VerifyAndCountMarkClosure cl(bitmap);

  HeapWord* old_top = region->top();

  // When top is equal to bottom the closure should not be

  // applied to any object because apply_to_marked_objects

  // will stop at HeapRegion::scan_limit which is equal to top.

  region->set_top(region->bottom());

  region->apply_to_marked_objects(bitmap, &cl);

  EXPECT_EQ(0, cl.count());

  cl.reset();

  // Set top to offset_1 and expect only to find 1 entry (bottom)

  region->set_top(region->bottom() + MARK_OFFSET_1);

  region->apply_to_marked_objects(bitmap, &cl);

  EXPECT_EQ(1, cl.count());

  cl.reset();

  // Set top to (offset_2 + 1) and expect only to find 3

  // entries (bottom, offset_1 and offset_2)

  region->set_top(region->bottom() + MARK_OFFSET_2 + MinObjAlignment);

  region->apply_to_marked_objects(bitmap, &cl);

  EXPECT_EQ(3, cl.count());

  cl.reset();

  // Still expect same 3 entries when top is (offset_3 - 1)

  region->set_top(region->bottom() + MARK_OFFSET_3 - MinObjAlignment);

  region->apply_to_marked_objects(bitmap, &cl);

  EXPECT_EQ(3, cl.count());

  cl.reset();

  // Setting top to end should render 4 entries.

  region->set_top(region->end());

  region->apply_to_marked_objects(bitmap, &cl);

  EXPECT_EQ(4, cl.count());

  cl.reset();

  region->set_top(old_top);

}

TEST_VM(HeapRegion, apply_to_marked_object) {

  if (!UseG1GC) {

    return;

  }

  // Run the test in our very own safepoint, because otherwise it

  // modifies a region behind the back of a possibly using allocation

  // or running GC.

  VM_HeapRegionApplyToMarkedObjectsTest op;

  ThreadInVMfromNative invm(JavaThread::current());

  VMThread::execute(&op);

}