/*

* Copyright (c) 1998, 2021, 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.

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*/

#include "precompiled.hpp"

#include "ci/ciEnv.hpp"

#include "ci/ciInstance.hpp"

#include "ci/ciMetadata.hpp"

#include "code/oopRecorder.inline.hpp"

#include "gc/shared/collectedHeap.hpp"

#include "memory/allocation.inline.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/jniHandles.inline.hpp"

#include "utilities/copy.hpp"

#ifdef ASSERT

template <class T> int ValueRecorder<T>::_find_index_calls = 0;

template <class T> int ValueRecorder<T>::_hit_indexes = 0;

template <class T> int ValueRecorder<T>::_missed_indexes = 0;

#endif //ASSERT

template <class T> ValueRecorder<T>::ValueRecorder(Arena* arena) {

_handles = NULL;

_indexes = NULL;

_arena = arena;

_complete = false;

}

template <class T> template <class X> ValueRecorder<T>::IndexCache<X>::IndexCache() {

assert(first_index > 0, "initial zero state of cache must be invalid index");

Copy::zero_to_bytes(&_cache[0], sizeof(_cache));

}

template <class T> int ValueRecorder<T>::size() {

_complete = true;

if (_handles == NULL) return 0;

return _handles->length() * sizeof(T);

}

template <class T> void ValueRecorder<T>::copy_values_to(nmethod* nm) {

assert(_complete, "must be frozen");

maybe_initialize(); // get non-null handles, even if we have no oops

nm->copy_values(_handles);

}

template <class T> void ValueRecorder<T>::maybe_initialize() {

if (_handles == NULL) {

if (_arena != NULL) {

_handles = new(_arena) GrowableArray<T>(_arena, 10, 0, 0);

_no_finds = new(_arena) GrowableArray<int>( _arena, 10, 0, 0);

} else {

_handles = new GrowableArray<T>(10, 0, 0);

_no_finds = new GrowableArray<int>( 10, 0, 0);

}

}

}

template <class T> T ValueRecorder<T>::at(int index) {

// there is always a NULL virtually present as first object

if (index == null_index) return NULL;

return _handles->at(index - first_index);

}

template <class T> int ValueRecorder<T>::add_handle(T h, bool make_findable) {

assert(!_complete, "cannot allocate more elements after size query");

maybe_initialize();

// indexing uses 1 as an origin--0 means null

int index = _handles->length() + first_index;

_handles->append(h);

// Support correct operation of find_index().

assert(!(make_findable && !is_real(h)), "nulls are not findable");

if (make_findable) {

// This index may be returned from find_index().

if (_indexes != NULL) {

int* cloc = _indexes->cache_location(h);

_indexes->set_cache_location_index(cloc, index);

} else if (index == index_cache_threshold && _arena != NULL) {

_indexes = new(_arena) IndexCache<T>();

for (int i = 0; i < _handles->length(); i++) {

// Load the cache with pre-existing elements.

int index0 = i + first_index;

if (_no_finds->contains(index0)) continue;

int* cloc = _indexes->cache_location(_handles->at(i));

_indexes->set_cache_location_index(cloc, index0);

}

}

} else if (is_real(h)) {

// Remember that this index is not to be returned from find_index().

// This case is rare, because most or all uses of allocate_index pass

// an argument of NULL or Universe::non_oop_word.

// Thus, the expected length of _no_finds is zero.

_no_finds->append(index);

}

return index;

}

template <class T> int ValueRecorder<T>::maybe_find_index(T h) {

debug_only(_find_index_calls++);

assert(!_complete, "cannot allocate more elements after size query");

maybe_initialize();

if (h == NULL) return null_index;

assert(is_real(h), "must be valid");

int* cloc = (_indexes == NULL)? NULL: _indexes->cache_location(h);

if (cloc != NULL) {

int cindex = _indexes->cache_location_index(cloc);

if (cindex == 0) {

return -1; // We know this handle is completely new.

}

if (cindex >= first_index && _handles->at(cindex - first_index) == h) {

debug_only(_hit_indexes++);

return cindex;

}

if (!_indexes->cache_location_collision(cloc)) {

return -1; // We know the current cache occupant is unique to that cloc.

}

}

// Not found in cache, due to a cache collision. (Or, no cache at all.)

// Do a linear search, most recent to oldest.

for (int i = _handles->length() - 1; i >= 0; i--) {

if (_handles->at(i) == h) {

int findex = i + first_index;

if (_no_finds->contains(findex)) continue; // oops; skip this one

if (cloc != NULL) {

_indexes->set_cache_location_index(cloc, findex);

}

debug_only(_missed_indexes++);

return findex;

}

}

return -1;

}

// Explicitly instantiate these types

template class ValueRecorder<Metadata*>;

template class ValueRecorder<jobject>;

oop ObjectLookup::ObjectEntry::oop_value() const { return JNIHandles::resolve(_value); }

ObjectLookup::ObjectLookup(): _values(4), _gc_count(Universe::heap()->total_collections()) {}

void ObjectLookup::maybe_resort() {

// The values are kept sorted by address which may be invalidated

// after a GC, so resort if a GC has occurred since last time.

if (_gc_count != Universe::heap()->total_collections()) {

_gc_count = Universe::heap()->total_collections();

_values.sort(sort_by_address);

}

}

int ObjectLookup::sort_by_address(oop a, oop b) {

// oopDesc::compare returns the opposite of what this function returned

return -(oopDesc::compare(a, b));

}

int ObjectLookup::sort_by_address(ObjectEntry* a, ObjectEntry* b) {

return sort_by_address(a->oop_value(), b->oop_value());

}

int ObjectLookup::sort_oop_by_address(oop const& a, ObjectEntry const& b) {

return sort_by_address(a, b.oop_value());

}

int ObjectLookup::find_index(jobject handle, OopRecorder* oop_recorder) {

if (handle == NULL) {

return 0;

}

oop object = JNIHandles::resolve(handle);

maybe_resort();

bool found;

int location = _values.find_sorted<oop, sort_oop_by_address>(object, found);

if (!found) {

jobject handle = JNIHandles::make_local(object);

ObjectEntry r(handle, oop_recorder->allocate_oop_index(handle));

_values.insert_before(location, r);

return r.index();

}

return _values.at(location).index();

}