/* * Copyright (c) 2013, 2019, 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. *
*/
class MetadataOnStackClosure : public MetadataClosure { void do_metadata(Metadata* m) { Metadata::mark_on_stack(m); }
};
// Walk metadata on the stack and mark it so that redefinition doesn't delete // it. Class unloading only deletes in-error class files, methods created by // the relocator and dummy constant pools. None of these appear anywhere except // in metadata Handles.
MetadataOnStackMark::MetadataOnStackMark(bool walk_all_metadata, bool redefinition_walk) {
assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
assert(_used_buffers == NULL, "sanity check");
assert(!_is_active, "MetadataOnStackMarks do not nest");
assert(!redefinition_walk || walk_all_metadata, "walk_all_metadata must be true for redefinition_walk");
NOT_PRODUCT(_is_active = true;)
if (walk_all_metadata) {
MetadataOnStackClosure md_on_stack;
Threads::metadata_do(&md_on_stack); if (redefinition_walk) { // We have to walk the whole code cache during redefinition.
CodeCache::metadata_do(&md_on_stack);
} else {
CodeCache::old_nmethods_do(&md_on_stack);
}
CompileBroker::mark_on_stack();
ThreadService::metadata_do(Metadata::mark_on_stack); #if INCLUDE_JVMCI
JVMCI::metadata_do(Metadata::mark_on_stack); #endif
}
}
MetadataOnStackMark::~MetadataOnStackMark() {
assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); // Unmark everything that was marked. Can't do the same walk because // redefine classes messes up the code cache so the set of methods // might not be the same.
retire_current_buffer();
MetadataOnStackBuffer* buffer = _used_buffers; while (buffer != NULL) { // Clear on stack state for all metadata.
size_t size = buffer->size(); for (size_t i = 0; i < size; i++) {
Metadata* md = buffer->at(i);
md->set_on_stack(false);
}
MetadataOnStackBuffer* next = buffer->next_used();
// Move the buffer to the free list.
buffer->clear();
buffer->set_next_used(NULL);
buffer->set_next_free(_free_buffers);
_free_buffers = buffer;
// Current buffer is full or we're ready to walk them, add it to the used list. void MetadataOnStackMark::retire_current_buffer() {
retire_buffer(_current_buffer);
_current_buffer = NULL;
}
// Get buffer off free list.
MetadataOnStackBuffer* MetadataOnStackMark::allocate_buffer() {
MetadataOnStackBuffer* allocated = _free_buffers;
if (allocated != NULL) {
_free_buffers = allocated->next_free();
}
if (allocated == NULL) {
allocated = new MetadataOnStackBuffer();
}
assert(!allocated->is_full(), "Should not be full: " PTR_FORMAT, p2i(allocated));
return allocated;
}
// Record which objects are marked so we can unmark the same objects. void MetadataOnStackMark::record(Metadata* m) {
assert(_is_active, "metadata on stack marking is active");
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