/**
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* \file
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* This is where objects are copied.
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*
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* Copyright 2001-2003 Ximian, Inc
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* Copyright 2003-2010 Novell, Inc.
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* Copyright (C) 2012 Xamarin Inc
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*
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* Licensed under the MIT license. See LICENSE file in the project root for full license information.
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*/
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/*
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* Defines
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*
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* GCObject* copy_object_no_checks (GCObject *obj, SgenGrayQueue *queue)
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*
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* which allocates new space for `obj`, copies it there, forwards `obj` to its new location,
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* and enqueues the copy into `queue`.
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*
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* To be defined by the includer:
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*
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* COLLECTOR_SERIAL_ALLOC_FOR_PROMOTION(vt, obj, objsize, has_refs)
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*
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* Allocates space for promoting object `obj`, with size `objsize`, and initizializes the
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* vtable with `vt`. `has_refs` indicates whether the object contains references.
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*
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* collector_pin_object(obj, queue)
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*
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* Called when no space for `obj` could be allocated. It must pin `obj` and enqueue it into
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* `queue` for scanning.
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*/
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extern guint64 stat_copy_object_called_nursery;
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extern guint64 stat_objects_copied_nursery;
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extern guint64 stat_nursery_copy_object_failed_from_space;
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extern guint64 stat_nursery_copy_object_failed_forwarded;
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extern guint64 stat_nursery_copy_object_failed_pinned;
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extern guint64 stat_slots_allocated_in_vain;
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/*
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* This function can be used even if the vtable of obj is not valid
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* anymore, which is the case in the parallel collector.
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*/
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static MONO_ALWAYS_INLINE void
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par_copy_object_no_checks (char *destination, GCVTable vt, void *obj, mword objsize)
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{
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sgen_client_pre_copy_checks (destination, vt, obj, objsize);
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binary_protocol_copy (obj, destination, vt, objsize);
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/* FIXME: assumes object layout */
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memcpy ((char*)destination + sizeof (mword), (char*)obj + sizeof (mword), objsize - sizeof (mword));
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/* adjust array->bounds */
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SGEN_ASSERT (9, sgen_vtable_get_descriptor (vt), "vtable %p has no gc descriptor", vt);
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sgen_client_update_copied_object (destination, vt, obj, objsize);
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}
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/*
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* Copies an object and enqueues it if a queue is given.
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* This can return OBJ itself on OOM.
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*/
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static MONO_NEVER_INLINE GCObject *
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copy_object_no_checks (GCObject *obj, SgenGrayQueue *queue)
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{
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GCVTable vt = SGEN_LOAD_VTABLE_UNCHECKED (obj);
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gboolean has_references = SGEN_VTABLE_HAS_REFERENCES (vt);
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mword objsize = SGEN_ALIGN_UP (sgen_client_par_object_get_size (vt, obj));
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void *destination = COLLECTOR_SERIAL_ALLOC_FOR_PROMOTION (vt, obj, objsize, has_references);
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if (G_UNLIKELY (!destination)) {
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/* FIXME: Is this path ever tested? */
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collector_pin_object (obj, queue);
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sgen_set_pinned_from_failed_allocation (objsize);
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return obj;
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}
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par_copy_object_no_checks ((char *)destination, vt, obj, objsize);
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/* set the forwarding pointer */
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SGEN_FORWARD_OBJECT (obj, destination);
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if (has_references) {
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SGEN_LOG (9, "Enqueuing gray object %p (%s)", destination, sgen_client_vtable_get_name (vt));
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GRAY_OBJECT_ENQUEUE_SERIAL (queue, (GCObject *)destination, sgen_vtable_get_descriptor (vt));
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}
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return (GCObject *)destination;
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}
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#if defined(COPY_OR_MARK_PARALLEL)
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static MONO_NEVER_INLINE GCObject *
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copy_object_no_checks_par (GCObject *obj, SgenGrayQueue *queue)
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{
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mword vtable_word = *(mword*)obj;
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GCObject *destination;
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destination = (GCObject*) SGEN_VTABLE_IS_FORWARDED (vtable_word);
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if (!destination) {
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GCVTable vt = (GCVTable) vtable_word;
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GCObject *final_destination;
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/*
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* At this point we know vt is not tagged and we shouldn't access the vtable through obj
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* since it could get copied at any time by another thread.
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*/
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gboolean has_references = SGEN_VTABLE_HAS_REFERENCES (vt);
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mword objsize = SGEN_ALIGN_UP (sgen_client_par_object_get_size (vt, obj));
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destination = COLLECTOR_PARALLEL_ALLOC_FOR_PROMOTION (vt, obj, objsize, has_references);
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par_copy_object_no_checks ((char*)destination, vt, obj, objsize);
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/* FIXME we might need a membar here so other threads see the vtable before we forward */
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/* set the forwarding pointer */
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SGEN_FORWARD_OBJECT_PAR (obj, destination, final_destination);
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if (destination == final_destination) {
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/* In a racing case, only the worker that allocated the object enqueues it */
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if (has_references) {
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SGEN_LOG (9, "Enqueuing gray object %p (%s)", destination, sgen_client_vtable_get_name (vt));
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GRAY_OBJECT_ENQUEUE_PARALLEL (queue, (GCObject *)destination, sgen_vtable_get_descriptor (vt));
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}
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} else {
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/*
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* Unlikely case. Clear the allocated object so it doesn't confuse nursery
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* card table scanning, since it can contain old invalid refs.
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* FIXME make sure it is not a problem if another threads scans it while we clear
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*/
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mono_gc_bzero_aligned (destination, objsize);
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destination = final_destination;
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}
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}
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return destination;
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}
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#endif
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#undef COLLECTOR_SERIAL_ALLOC_FOR_PROMOTION
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#undef COLLECTOR_PARALLEL_ALLOC_FOR_PROMOTION
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#undef collector_pin_object
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#undef COPY_OR_MARK_PARALLEL
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