зеркало из https://github.com/mozilla/gecko-dev.git
4227 строки
117 KiB
C++
4227 строки
117 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//
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// This file implements a garbage-cycle collector based on the paper
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//
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// Concurrent Cycle Collection in Reference Counted Systems
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// Bacon & Rajan (2001), ECOOP 2001 / Springer LNCS vol 2072
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//
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// We are not using the concurrent or acyclic cases of that paper; so
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// the green, red and orange colors are not used.
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//
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// The collector is based on tracking pointers of four colors:
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//
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// Black nodes are definitely live. If we ever determine a node is
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// black, it's ok to forget about, drop from our records.
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//
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// White nodes are definitely garbage cycles. Once we finish with our
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// scanning, we unlink all the white nodes and expect that by
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// unlinking them they will self-destruct (since a garbage cycle is
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// only keeping itself alive with internal links, by definition).
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//
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// Snow-white is an addition to the original algorithm. Snow-white object
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// has reference count zero and is just waiting for deletion.
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//
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// Grey nodes are being scanned. Nodes that turn grey will turn
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// either black if we determine that they're live, or white if we
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// determine that they're a garbage cycle. After the main collection
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// algorithm there should be no grey nodes.
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//
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// Purple nodes are *candidates* for being scanned. They are nodes we
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// haven't begun scanning yet because they're not old enough, or we're
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// still partway through the algorithm.
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//
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// XPCOM objects participating in garbage-cycle collection are obliged
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// to inform us when they ought to turn purple; that is, when their
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// refcount transitions from N+1 -> N, for nonzero N. Furthermore we
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// require that *after* an XPCOM object has informed us of turning
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// purple, they will tell us when they either transition back to being
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// black (incremented refcount) or are ultimately deleted.
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// Incremental cycle collection
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//
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// Beyond the simple state machine required to implement incremental
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// collection, the CC needs to be able to compensate for things the browser
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// is doing during the collection. There are two kinds of problems. For each
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// of these, there are two cases to deal with: purple-buffered C++ objects
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// and JS objects.
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// The first problem is that an object in the CC's graph can become garbage.
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// This is bad because the CC touches the objects in its graph at every
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// stage of its operation.
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//
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// All cycle collected C++ objects that die during a cycle collection
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// will end up actually getting deleted by the SnowWhiteKiller. Before
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// the SWK deletes an object, it checks if an ICC is running, and if so,
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// if the object is in the graph. If it is, the CC clears mPointer and
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// mParticipant so it does not point to the raw object any more. Because
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// objects could die any time the CC returns to the mutator, any time the CC
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// accesses a PtrInfo it must perform a null check on mParticipant to
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// ensure the object has not gone away.
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//
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// JS objects don't always run finalizers, so the CC can't remove them from
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// the graph when they die. Fortunately, JS objects can only die during a GC,
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// so if a GC is begun during an ICC, the browser synchronously finishes off
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// the ICC, which clears the entire CC graph. If the GC and CC are scheduled
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// properly, this should be rare.
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//
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// The second problem is that objects in the graph can be changed, say by
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// being addrefed or released, or by having a field updated, after the object
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// has been added to the graph. The problem is that ICC can miss a newly
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// created reference to an object, and end up unlinking an object that is
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// actually alive.
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//
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// The basic idea of the solution, from "An on-the-fly Reference Counting
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// Garbage Collector for Java" by Levanoni and Petrank, is to notice if an
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// object has had an additional reference to it created during the collection,
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// and if so, don't collect it during the current collection. This avoids having
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// to rerun the scan as in Bacon & Rajan 2001.
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//
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// For cycle collected C++ objects, we modify AddRef to place the object in
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// the purple buffer, in addition to Release. Then, in the CC, we treat any
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// objects in the purple buffer as being alive, after graph building has
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// completed. Because they are in the purple buffer, they will be suspected
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// in the next CC, so there's no danger of leaks. This is imprecise, because
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// we will treat as live an object that has been Released but not AddRefed
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// during graph building, but that's probably rare enough that the additional
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// bookkeeping overhead is not worthwhile.
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//
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// For JS objects, the cycle collector is only looking at gray objects. If a
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// gray object is touched during ICC, it will be made black by UnmarkGray.
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// Thus, if a JS object has become black during the ICC, we treat it as live.
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// Merged JS zones have to be handled specially: we scan all zone globals.
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// If any are black, we treat the zone as being black.
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// Safety
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//
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// An XPCOM object is either scan-safe or scan-unsafe, purple-safe or
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// purple-unsafe.
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//
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// An nsISupports object is scan-safe if:
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//
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// - It can be QI'ed to |nsXPCOMCycleCollectionParticipant|, though
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// this operation loses ISupports identity (like nsIClassInfo).
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// - Additionally, the operation |traverse| on the resulting
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// nsXPCOMCycleCollectionParticipant does not cause *any* refcount
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// adjustment to occur (no AddRef / Release calls).
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//
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// A non-nsISupports ("native") object is scan-safe by explicitly
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// providing its nsCycleCollectionParticipant.
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//
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// An object is purple-safe if it satisfies the following properties:
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//
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// - The object is scan-safe.
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//
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// When we receive a pointer |ptr| via
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// |nsCycleCollector::suspect(ptr)|, we assume it is purple-safe. We
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// can check the scan-safety, but have no way to ensure the
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// purple-safety; objects must obey, or else the entire system falls
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// apart. Don't involve an object in this scheme if you can't
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// guarantee its purple-safety. The easiest way to ensure that an
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// object is purple-safe is to use nsCycleCollectingAutoRefCnt.
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//
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// When we have a scannable set of purple nodes ready, we begin
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// our walks. During the walks, the nodes we |traverse| should only
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// feed us more scan-safe nodes, and should not adjust the refcounts
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// of those nodes.
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//
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// We do not |AddRef| or |Release| any objects during scanning. We
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// rely on the purple-safety of the roots that call |suspect| to
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// hold, such that we will clear the pointer from the purple buffer
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// entry to the object before it is destroyed. The pointers that are
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// merely scan-safe we hold only for the duration of scanning, and
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// there should be no objects released from the scan-safe set during
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// the scan.
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//
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// We *do* call |Root| and |Unroot| on every white object, on
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// either side of the calls to |Unlink|. This keeps the set of white
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// objects alive during the unlinking.
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//
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#if !defined(__MINGW32__)
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#ifdef WIN32
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#include <crtdbg.h>
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#include <errno.h>
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#endif
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#endif
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#include "base/process_util.h"
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#include "mozilla/ArrayUtils.h"
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#include "mozilla/AutoRestore.h"
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#include "mozilla/CycleCollectedJSContext.h"
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#include "mozilla/DebugOnly.h"
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#include "mozilla/HoldDropJSObjects.h"
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/* This must occur *after* base/process_util.h to avoid typedefs conflicts. */
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#include "mozilla/LinkedList.h"
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#include "mozilla/MemoryReporting.h"
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#include "mozilla/SegmentedVector.h"
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#include "nsCycleCollectionParticipant.h"
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#include "nsCycleCollectionNoteRootCallback.h"
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#include "nsDeque.h"
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#include "nsCycleCollector.h"
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#include "nsThreadUtils.h"
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#include "nsXULAppAPI.h"
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#include "prenv.h"
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#include "nsPrintfCString.h"
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#include "nsTArray.h"
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#include "nsIConsoleService.h"
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#include "mozilla/Attributes.h"
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#include "nsICycleCollectorListener.h"
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#include "nsIMemoryReporter.h"
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#include "nsIFile.h"
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#include "nsDumpUtils.h"
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#include "xpcpublic.h"
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#include "GeckoProfiler.h"
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#include <stdint.h>
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#include <stdio.h>
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#include "mozilla/AutoGlobalTimelineMarker.h"
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#include "mozilla/Likely.h"
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#include "mozilla/PoisonIOInterposer.h"
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#include "mozilla/Telemetry.h"
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#include "mozilla/ThreadLocal.h"
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#ifdef MOZ_CRASHREPORTER
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#include "nsExceptionHandler.h"
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#endif
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using namespace mozilla;
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//#define COLLECT_TIME_DEBUG
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// Enable assertions that are useful for diagnosing errors in graph construction.
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//#define DEBUG_CC_GRAPH
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#define DEFAULT_SHUTDOWN_COLLECTIONS 5
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// One to do the freeing, then another to detect there is no more work to do.
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#define NORMAL_SHUTDOWN_COLLECTIONS 2
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// Cycle collector environment variables
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//
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// MOZ_CC_LOG_ALL: If defined, always log cycle collector heaps.
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//
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// MOZ_CC_LOG_SHUTDOWN: If defined, log cycle collector heaps at shutdown.
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//
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// MOZ_CC_LOG_THREAD: If set to "main", only automatically log main thread
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// CCs. If set to "worker", only automatically log worker CCs. If set to "all",
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// log either. The default value is "all". This must be used with either
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// MOZ_CC_LOG_ALL or MOZ_CC_LOG_SHUTDOWN for it to do anything.
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//
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// MOZ_CC_LOG_PROCESS: If set to "main", only automatically log main process
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// CCs. If set to "content", only automatically log tab CCs. If set to
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// "plugins", only automatically log plugin CCs. If set to "all", log
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// everything. The default value is "all". This must be used with either
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// MOZ_CC_LOG_ALL or MOZ_CC_LOG_SHUTDOWN for it to do anything.
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//
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// MOZ_CC_ALL_TRACES: If set to "all", any cycle collector
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// logging done will be WantAllTraces, which disables
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// various cycle collector optimizations to give a fuller picture of
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// the heap. If set to "shutdown", only shutdown logging will be WantAllTraces.
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// The default is none.
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//
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// MOZ_CC_RUN_DURING_SHUTDOWN: In non-DEBUG or builds, if this is set,
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// run cycle collections at shutdown.
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//
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// MOZ_CC_LOG_DIRECTORY: The directory in which logs are placed (such as
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// logs from MOZ_CC_LOG_ALL and MOZ_CC_LOG_SHUTDOWN, or other uses
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// of nsICycleCollectorListener)
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// Various parameters of this collector can be tuned using environment
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// variables.
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struct nsCycleCollectorParams
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{
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bool mLogAll;
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bool mLogShutdown;
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bool mAllTracesAll;
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bool mAllTracesShutdown;
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bool mLogThisThread;
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nsCycleCollectorParams() :
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mLogAll(PR_GetEnv("MOZ_CC_LOG_ALL") != nullptr),
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mLogShutdown(PR_GetEnv("MOZ_CC_LOG_SHUTDOWN") != nullptr),
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mAllTracesAll(false),
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mAllTracesShutdown(false)
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{
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const char* logThreadEnv = PR_GetEnv("MOZ_CC_LOG_THREAD");
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bool threadLogging = true;
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if (logThreadEnv && !!strcmp(logThreadEnv, "all")) {
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if (NS_IsMainThread()) {
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threadLogging = !strcmp(logThreadEnv, "main");
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} else {
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threadLogging = !strcmp(logThreadEnv, "worker");
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}
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}
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const char* logProcessEnv = PR_GetEnv("MOZ_CC_LOG_PROCESS");
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bool processLogging = true;
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if (logProcessEnv && !!strcmp(logProcessEnv, "all")) {
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switch (XRE_GetProcessType()) {
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case GeckoProcessType_Default:
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processLogging = !strcmp(logProcessEnv, "main");
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break;
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case GeckoProcessType_Plugin:
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processLogging = !strcmp(logProcessEnv, "plugins");
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break;
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case GeckoProcessType_Content:
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processLogging = !strcmp(logProcessEnv, "content");
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break;
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default:
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processLogging = false;
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break;
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}
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}
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mLogThisThread = threadLogging && processLogging;
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const char* allTracesEnv = PR_GetEnv("MOZ_CC_ALL_TRACES");
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if (allTracesEnv) {
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if (!strcmp(allTracesEnv, "all")) {
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mAllTracesAll = true;
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} else if (!strcmp(allTracesEnv, "shutdown")) {
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mAllTracesShutdown = true;
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}
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}
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}
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bool LogThisCC(bool aIsShutdown)
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{
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return (mLogAll || (aIsShutdown && mLogShutdown)) && mLogThisThread;
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}
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bool AllTracesThisCC(bool aIsShutdown)
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{
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return mAllTracesAll || (aIsShutdown && mAllTracesShutdown);
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}
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};
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#ifdef COLLECT_TIME_DEBUG
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class TimeLog
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{
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public:
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TimeLog() : mLastCheckpoint(TimeStamp::Now())
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{
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}
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void
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Checkpoint(const char* aEvent)
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{
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TimeStamp now = TimeStamp::Now();
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double dur = (now - mLastCheckpoint).ToMilliseconds();
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if (dur >= 0.5) {
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printf("cc: %s took %.1fms\n", aEvent, dur);
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}
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mLastCheckpoint = now;
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}
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private:
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TimeStamp mLastCheckpoint;
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};
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#else
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class TimeLog
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{
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public:
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TimeLog()
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{
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}
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void Checkpoint(const char* aEvent)
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{
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}
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};
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#endif
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////////////////////////////////////////////////////////////////////////
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// Base types
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////////////////////////////////////////////////////////////////////////
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struct PtrInfo;
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class EdgePool
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{
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public:
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// EdgePool allocates arrays of void*, primarily to hold PtrInfo*.
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// However, at the end of a block, the last two pointers are a null
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// and then a void** pointing to the next block. This allows
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// EdgePool::Iterators to be a single word but still capable of crossing
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// block boundaries.
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EdgePool()
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{
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mSentinelAndBlocks[0].block = nullptr;
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mSentinelAndBlocks[1].block = nullptr;
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}
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~EdgePool()
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{
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MOZ_ASSERT(!mSentinelAndBlocks[0].block &&
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!mSentinelAndBlocks[1].block,
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"Didn't call Clear()?");
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}
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void Clear()
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{
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EdgeBlock* b = EdgeBlocks();
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while (b) {
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EdgeBlock* next = b->Next();
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delete b;
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b = next;
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}
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mSentinelAndBlocks[0].block = nullptr;
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mSentinelAndBlocks[1].block = nullptr;
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}
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#ifdef DEBUG
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bool IsEmpty()
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{
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return !mSentinelAndBlocks[0].block &&
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!mSentinelAndBlocks[1].block;
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}
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#endif
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private:
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struct EdgeBlock;
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union PtrInfoOrBlock
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{
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// Use a union to avoid reinterpret_cast and the ensuing
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// potential aliasing bugs.
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PtrInfo* ptrInfo;
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EdgeBlock* block;
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};
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struct EdgeBlock
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{
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enum { EdgeBlockSize = 16 * 1024 };
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PtrInfoOrBlock mPointers[EdgeBlockSize];
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EdgeBlock()
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{
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mPointers[EdgeBlockSize - 2].block = nullptr; // sentinel
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mPointers[EdgeBlockSize - 1].block = nullptr; // next block pointer
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}
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EdgeBlock*& Next()
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{
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return mPointers[EdgeBlockSize - 1].block;
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}
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PtrInfoOrBlock* Start()
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{
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return &mPointers[0];
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}
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PtrInfoOrBlock* End()
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{
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return &mPointers[EdgeBlockSize - 2];
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}
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};
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// Store the null sentinel so that we can have valid iterators
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// before adding any edges and without adding any blocks.
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PtrInfoOrBlock mSentinelAndBlocks[2];
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EdgeBlock*& EdgeBlocks()
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{
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return mSentinelAndBlocks[1].block;
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}
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EdgeBlock* EdgeBlocks() const
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{
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return mSentinelAndBlocks[1].block;
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}
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public:
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class Iterator
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{
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public:
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Iterator() : mPointer(nullptr) {}
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explicit Iterator(PtrInfoOrBlock* aPointer) : mPointer(aPointer) {}
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Iterator(const Iterator& aOther) : mPointer(aOther.mPointer) {}
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Iterator& operator++()
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{
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if (!mPointer->ptrInfo) {
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// Null pointer is a sentinel for link to the next block.
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mPointer = (mPointer + 1)->block->mPointers;
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}
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++mPointer;
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return *this;
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}
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PtrInfo* operator*() const
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{
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if (!mPointer->ptrInfo) {
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// Null pointer is a sentinel for link to the next block.
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return (mPointer + 1)->block->mPointers->ptrInfo;
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}
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return mPointer->ptrInfo;
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}
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bool operator==(const Iterator& aOther) const
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{
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return mPointer == aOther.mPointer;
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}
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bool operator!=(const Iterator& aOther) const
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{
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return mPointer != aOther.mPointer;
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}
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#ifdef DEBUG_CC_GRAPH
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bool Initialized() const
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{
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return mPointer != nullptr;
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}
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#endif
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private:
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PtrInfoOrBlock* mPointer;
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};
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class Builder;
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friend class Builder;
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class Builder
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{
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public:
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explicit Builder(EdgePool& aPool)
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: mCurrent(&aPool.mSentinelAndBlocks[0])
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, mBlockEnd(&aPool.mSentinelAndBlocks[0])
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, mNextBlockPtr(&aPool.EdgeBlocks())
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{
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}
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Iterator Mark()
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{
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return Iterator(mCurrent);
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}
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void Add(PtrInfo* aEdge)
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{
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if (mCurrent == mBlockEnd) {
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EdgeBlock* b = new EdgeBlock();
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*mNextBlockPtr = b;
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mCurrent = b->Start();
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mBlockEnd = b->End();
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mNextBlockPtr = &b->Next();
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}
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(mCurrent++)->ptrInfo = aEdge;
|
|
}
|
|
private:
|
|
// mBlockEnd points to space for null sentinel
|
|
PtrInfoOrBlock* mCurrent;
|
|
PtrInfoOrBlock* mBlockEnd;
|
|
EdgeBlock** mNextBlockPtr;
|
|
};
|
|
|
|
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
|
|
{
|
|
size_t n = 0;
|
|
EdgeBlock* b = EdgeBlocks();
|
|
while (b) {
|
|
n += aMallocSizeOf(b);
|
|
b = b->Next();
|
|
}
|
|
return n;
|
|
}
|
|
};
|
|
|
|
#ifdef DEBUG_CC_GRAPH
|
|
#define CC_GRAPH_ASSERT(b) MOZ_ASSERT(b)
|
|
#else
|
|
#define CC_GRAPH_ASSERT(b)
|
|
#endif
|
|
|
|
#define CC_TELEMETRY(_name, _value) \
|
|
PR_BEGIN_MACRO \
|
|
if (NS_IsMainThread()) { \
|
|
Telemetry::Accumulate(Telemetry::CYCLE_COLLECTOR##_name, _value); \
|
|
} else { \
|
|
Telemetry::Accumulate(Telemetry::CYCLE_COLLECTOR_WORKER##_name, _value); \
|
|
} \
|
|
PR_END_MACRO
|
|
|
|
enum NodeColor { black, white, grey };
|
|
|
|
// This structure should be kept as small as possible; we may expect
|
|
// hundreds of thousands of them to be allocated and touched
|
|
// repeatedly during each cycle collection.
|
|
|
|
struct PtrInfo
|
|
{
|
|
void* mPointer;
|
|
nsCycleCollectionParticipant* mParticipant;
|
|
uint32_t mColor : 2;
|
|
uint32_t mInternalRefs : 30;
|
|
uint32_t mRefCount;
|
|
private:
|
|
EdgePool::Iterator mFirstChild;
|
|
|
|
static const uint32_t kInitialRefCount = UINT32_MAX - 1;
|
|
|
|
public:
|
|
|
|
PtrInfo(void* aPointer, nsCycleCollectionParticipant* aParticipant)
|
|
: mPointer(aPointer),
|
|
mParticipant(aParticipant),
|
|
mColor(grey),
|
|
mInternalRefs(0),
|
|
mRefCount(kInitialRefCount),
|
|
mFirstChild()
|
|
{
|
|
MOZ_ASSERT(aParticipant);
|
|
|
|
// We initialize mRefCount to a large non-zero value so
|
|
// that it doesn't look like a JS object to the cycle collector
|
|
// in the case where the object dies before being traversed.
|
|
MOZ_ASSERT(!IsGrayJS() && !IsBlackJS());
|
|
}
|
|
|
|
// Allow NodePool::NodeBlock's constructor to compile.
|
|
PtrInfo()
|
|
{
|
|
NS_NOTREACHED("should never be called");
|
|
}
|
|
|
|
bool IsGrayJS() const
|
|
{
|
|
return mRefCount == 0;
|
|
}
|
|
|
|
bool IsBlackJS() const
|
|
{
|
|
return mRefCount == UINT32_MAX;
|
|
}
|
|
|
|
bool WasTraversed() const
|
|
{
|
|
return mRefCount != kInitialRefCount;
|
|
}
|
|
|
|
EdgePool::Iterator FirstChild() const
|
|
{
|
|
CC_GRAPH_ASSERT(mFirstChild.Initialized());
|
|
return mFirstChild;
|
|
}
|
|
|
|
// this PtrInfo must be part of a NodePool
|
|
EdgePool::Iterator LastChild() const
|
|
{
|
|
CC_GRAPH_ASSERT((this + 1)->mFirstChild.Initialized());
|
|
return (this + 1)->mFirstChild;
|
|
}
|
|
|
|
void SetFirstChild(EdgePool::Iterator aFirstChild)
|
|
{
|
|
CC_GRAPH_ASSERT(aFirstChild.Initialized());
|
|
mFirstChild = aFirstChild;
|
|
}
|
|
|
|
// this PtrInfo must be part of a NodePool
|
|
void SetLastChild(EdgePool::Iterator aLastChild)
|
|
{
|
|
CC_GRAPH_ASSERT(aLastChild.Initialized());
|
|
(this + 1)->mFirstChild = aLastChild;
|
|
}
|
|
};
|
|
|
|
/**
|
|
* A structure designed to be used like a linked list of PtrInfo, except
|
|
* it allocates many PtrInfos at a time.
|
|
*/
|
|
class NodePool
|
|
{
|
|
private:
|
|
// The -2 allows us to use |NodeBlockSize + 1| for |mEntries|, and fit
|
|
// |mNext|, all without causing slop.
|
|
enum { NodeBlockSize = 4 * 1024 - 2 };
|
|
|
|
struct NodeBlock
|
|
{
|
|
// We create and destroy NodeBlock using moz_xmalloc/free rather than new
|
|
// and delete to avoid calling its constructor and destructor.
|
|
NodeBlock()
|
|
{
|
|
NS_NOTREACHED("should never be called");
|
|
|
|
// Ensure NodeBlock is the right size (see the comment on NodeBlockSize
|
|
// above).
|
|
static_assert(
|
|
sizeof(NodeBlock) == 81904 || // 32-bit; equals 19.996 x 4 KiB pages
|
|
sizeof(NodeBlock) == 131048, // 64-bit; equals 31.994 x 4 KiB pages
|
|
"ill-sized NodeBlock"
|
|
);
|
|
}
|
|
~NodeBlock()
|
|
{
|
|
NS_NOTREACHED("should never be called");
|
|
}
|
|
|
|
NodeBlock* mNext;
|
|
PtrInfo mEntries[NodeBlockSize + 1]; // +1 to store last child of last node
|
|
};
|
|
|
|
public:
|
|
NodePool()
|
|
: mBlocks(nullptr)
|
|
, mLast(nullptr)
|
|
{
|
|
}
|
|
|
|
~NodePool()
|
|
{
|
|
MOZ_ASSERT(!mBlocks, "Didn't call Clear()?");
|
|
}
|
|
|
|
void Clear()
|
|
{
|
|
NodeBlock* b = mBlocks;
|
|
while (b) {
|
|
NodeBlock* n = b->mNext;
|
|
free(b);
|
|
b = n;
|
|
}
|
|
|
|
mBlocks = nullptr;
|
|
mLast = nullptr;
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
bool IsEmpty()
|
|
{
|
|
return !mBlocks && !mLast;
|
|
}
|
|
#endif
|
|
|
|
class Builder;
|
|
friend class Builder;
|
|
class Builder
|
|
{
|
|
public:
|
|
explicit Builder(NodePool& aPool)
|
|
: mNextBlock(&aPool.mBlocks)
|
|
, mNext(aPool.mLast)
|
|
, mBlockEnd(nullptr)
|
|
{
|
|
MOZ_ASSERT(!aPool.mBlocks && !aPool.mLast, "pool not empty");
|
|
}
|
|
PtrInfo* Add(void* aPointer, nsCycleCollectionParticipant* aParticipant)
|
|
{
|
|
if (mNext == mBlockEnd) {
|
|
NodeBlock* block = static_cast<NodeBlock*>(malloc(sizeof(NodeBlock)));
|
|
if (!block) {
|
|
return nullptr;
|
|
}
|
|
|
|
*mNextBlock = block;
|
|
mNext = block->mEntries;
|
|
mBlockEnd = block->mEntries + NodeBlockSize;
|
|
block->mNext = nullptr;
|
|
mNextBlock = &block->mNext;
|
|
}
|
|
return new (mozilla::KnownNotNull, mNext++) PtrInfo(aPointer, aParticipant);
|
|
}
|
|
private:
|
|
NodeBlock** mNextBlock;
|
|
PtrInfo*& mNext;
|
|
PtrInfo* mBlockEnd;
|
|
};
|
|
|
|
class Enumerator;
|
|
friend class Enumerator;
|
|
class Enumerator
|
|
{
|
|
public:
|
|
explicit Enumerator(NodePool& aPool)
|
|
: mFirstBlock(aPool.mBlocks)
|
|
, mCurBlock(nullptr)
|
|
, mNext(nullptr)
|
|
, mBlockEnd(nullptr)
|
|
, mLast(aPool.mLast)
|
|
{
|
|
}
|
|
|
|
bool IsDone() const
|
|
{
|
|
return mNext == mLast;
|
|
}
|
|
|
|
bool AtBlockEnd() const
|
|
{
|
|
return mNext == mBlockEnd;
|
|
}
|
|
|
|
PtrInfo* GetNext()
|
|
{
|
|
MOZ_ASSERT(!IsDone(), "calling GetNext when done");
|
|
if (mNext == mBlockEnd) {
|
|
NodeBlock* nextBlock = mCurBlock ? mCurBlock->mNext : mFirstBlock;
|
|
mNext = nextBlock->mEntries;
|
|
mBlockEnd = mNext + NodeBlockSize;
|
|
mCurBlock = nextBlock;
|
|
}
|
|
return mNext++;
|
|
}
|
|
private:
|
|
// mFirstBlock is a reference to allow an Enumerator to be constructed
|
|
// for an empty graph.
|
|
NodeBlock*& mFirstBlock;
|
|
NodeBlock* mCurBlock;
|
|
// mNext is the next value we want to return, unless mNext == mBlockEnd
|
|
// NB: mLast is a reference to allow enumerating while building!
|
|
PtrInfo* mNext;
|
|
PtrInfo* mBlockEnd;
|
|
PtrInfo*& mLast;
|
|
};
|
|
|
|
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
|
|
{
|
|
// We don't measure the things pointed to by mEntries[] because those
|
|
// pointers are non-owning.
|
|
size_t n = 0;
|
|
NodeBlock* b = mBlocks;
|
|
while (b) {
|
|
n += aMallocSizeOf(b);
|
|
b = b->mNext;
|
|
}
|
|
return n;
|
|
}
|
|
|
|
private:
|
|
NodeBlock* mBlocks;
|
|
PtrInfo* mLast;
|
|
};
|
|
|
|
|
|
// Declarations for mPtrToNodeMap.
|
|
|
|
struct PtrToNodeEntry : public PLDHashEntryHdr
|
|
{
|
|
// The key is mNode->mPointer
|
|
PtrInfo* mNode;
|
|
};
|
|
|
|
static bool
|
|
PtrToNodeMatchEntry(const PLDHashEntryHdr* aEntry, const void* aKey)
|
|
{
|
|
const PtrToNodeEntry* n = static_cast<const PtrToNodeEntry*>(aEntry);
|
|
return n->mNode->mPointer == aKey;
|
|
}
|
|
|
|
static PLDHashTableOps PtrNodeOps = {
|
|
PLDHashTable::HashVoidPtrKeyStub,
|
|
PtrToNodeMatchEntry,
|
|
PLDHashTable::MoveEntryStub,
|
|
PLDHashTable::ClearEntryStub,
|
|
nullptr
|
|
};
|
|
|
|
|
|
struct WeakMapping
|
|
{
|
|
// map and key will be null if the corresponding objects are GC marked
|
|
PtrInfo* mMap;
|
|
PtrInfo* mKey;
|
|
PtrInfo* mKeyDelegate;
|
|
PtrInfo* mVal;
|
|
};
|
|
|
|
class CCGraphBuilder;
|
|
|
|
struct CCGraph
|
|
{
|
|
NodePool mNodes;
|
|
EdgePool mEdges;
|
|
nsTArray<WeakMapping> mWeakMaps;
|
|
uint32_t mRootCount;
|
|
|
|
private:
|
|
PLDHashTable mPtrToNodeMap;
|
|
bool mOutOfMemory;
|
|
|
|
static const uint32_t kInitialMapLength = 16384;
|
|
|
|
public:
|
|
CCGraph()
|
|
: mRootCount(0)
|
|
, mPtrToNodeMap(&PtrNodeOps, sizeof(PtrToNodeEntry), kInitialMapLength)
|
|
, mOutOfMemory(false)
|
|
{}
|
|
|
|
~CCGraph() {}
|
|
|
|
void Init()
|
|
{
|
|
MOZ_ASSERT(IsEmpty(), "Failed to call CCGraph::Clear");
|
|
}
|
|
|
|
void Clear()
|
|
{
|
|
mNodes.Clear();
|
|
mEdges.Clear();
|
|
mWeakMaps.Clear();
|
|
mRootCount = 0;
|
|
mPtrToNodeMap.ClearAndPrepareForLength(kInitialMapLength);
|
|
mOutOfMemory = false;
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
bool IsEmpty()
|
|
{
|
|
return mNodes.IsEmpty() && mEdges.IsEmpty() &&
|
|
mWeakMaps.IsEmpty() && mRootCount == 0 &&
|
|
mPtrToNodeMap.EntryCount() == 0;
|
|
}
|
|
#endif
|
|
|
|
PtrInfo* FindNode(void* aPtr);
|
|
PtrToNodeEntry* AddNodeToMap(void* aPtr);
|
|
void RemoveObjectFromMap(void* aObject);
|
|
|
|
uint32_t MapCount() const
|
|
{
|
|
return mPtrToNodeMap.EntryCount();
|
|
}
|
|
|
|
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
|
|
{
|
|
size_t n = 0;
|
|
|
|
n += mNodes.SizeOfExcludingThis(aMallocSizeOf);
|
|
n += mEdges.SizeOfExcludingThis(aMallocSizeOf);
|
|
|
|
// We don't measure what the WeakMappings point to, because the
|
|
// pointers are non-owning.
|
|
n += mWeakMaps.ShallowSizeOfExcludingThis(aMallocSizeOf);
|
|
|
|
n += mPtrToNodeMap.ShallowSizeOfExcludingThis(aMallocSizeOf);
|
|
|
|
return n;
|
|
}
|
|
|
|
private:
|
|
PtrToNodeEntry* FindNodeEntry(void* aPtr)
|
|
{
|
|
return static_cast<PtrToNodeEntry*>(mPtrToNodeMap.Search(aPtr));
|
|
}
|
|
};
|
|
|
|
PtrInfo*
|
|
CCGraph::FindNode(void* aPtr)
|
|
{
|
|
PtrToNodeEntry* e = FindNodeEntry(aPtr);
|
|
return e ? e->mNode : nullptr;
|
|
}
|
|
|
|
PtrToNodeEntry*
|
|
CCGraph::AddNodeToMap(void* aPtr)
|
|
{
|
|
JS::AutoSuppressGCAnalysis suppress;
|
|
if (mOutOfMemory) {
|
|
return nullptr;
|
|
}
|
|
|
|
auto e = static_cast<PtrToNodeEntry*>(mPtrToNodeMap.Add(aPtr, fallible));
|
|
if (!e) {
|
|
mOutOfMemory = true;
|
|
MOZ_ASSERT(false, "Ran out of memory while building cycle collector graph");
|
|
return nullptr;
|
|
}
|
|
return e;
|
|
}
|
|
|
|
void
|
|
CCGraph::RemoveObjectFromMap(void* aObj)
|
|
{
|
|
PtrToNodeEntry* e = FindNodeEntry(aObj);
|
|
PtrInfo* pinfo = e ? e->mNode : nullptr;
|
|
if (pinfo) {
|
|
mPtrToNodeMap.RemoveEntry(e);
|
|
|
|
pinfo->mPointer = nullptr;
|
|
pinfo->mParticipant = nullptr;
|
|
}
|
|
}
|
|
|
|
|
|
static nsISupports*
|
|
CanonicalizeXPCOMParticipant(nsISupports* aIn)
|
|
{
|
|
nsISupports* out = nullptr;
|
|
aIn->QueryInterface(NS_GET_IID(nsCycleCollectionISupports),
|
|
reinterpret_cast<void**>(&out));
|
|
return out;
|
|
}
|
|
|
|
static inline void
|
|
ToParticipant(nsISupports* aPtr, nsXPCOMCycleCollectionParticipant** aCp);
|
|
|
|
static void
|
|
CanonicalizeParticipant(void** aParti, nsCycleCollectionParticipant** aCp)
|
|
{
|
|
// If the participant is null, this is an nsISupports participant,
|
|
// so we must QI to get the real participant.
|
|
|
|
if (!*aCp) {
|
|
nsISupports* nsparti = static_cast<nsISupports*>(*aParti);
|
|
nsparti = CanonicalizeXPCOMParticipant(nsparti);
|
|
NS_ASSERTION(nsparti,
|
|
"Don't add objects that don't participate in collection!");
|
|
nsXPCOMCycleCollectionParticipant* xcp;
|
|
ToParticipant(nsparti, &xcp);
|
|
*aParti = nsparti;
|
|
*aCp = xcp;
|
|
}
|
|
}
|
|
|
|
struct nsPurpleBufferEntry
|
|
{
|
|
union
|
|
{
|
|
void* mObject; // when low bit unset
|
|
nsPurpleBufferEntry* mNextInFreeList; // when low bit set
|
|
};
|
|
|
|
nsCycleCollectingAutoRefCnt* mRefCnt;
|
|
|
|
nsCycleCollectionParticipant* mParticipant; // nullptr for nsISupports
|
|
};
|
|
|
|
class nsCycleCollector;
|
|
|
|
struct nsPurpleBuffer
|
|
{
|
|
private:
|
|
struct PurpleBlock
|
|
{
|
|
PurpleBlock* mNext;
|
|
// Try to match the size of a jemalloc bucket, to minimize slop bytes.
|
|
// - On 32-bit platforms sizeof(nsPurpleBufferEntry) is 12, so mEntries
|
|
// is 16,380 bytes, which leaves 4 bytes for mNext.
|
|
// - On 64-bit platforms sizeof(nsPurpleBufferEntry) is 24, so mEntries
|
|
// is 32,544 bytes, which leaves 8 bytes for mNext.
|
|
nsPurpleBufferEntry mEntries[1365];
|
|
|
|
PurpleBlock() : mNext(nullptr)
|
|
{
|
|
// Ensure PurpleBlock is the right size (see above).
|
|
static_assert(
|
|
sizeof(PurpleBlock) == 16384 || // 32-bit
|
|
sizeof(PurpleBlock) == 32768, // 64-bit
|
|
"ill-sized nsPurpleBuffer::PurpleBlock"
|
|
);
|
|
|
|
InitNextPointers();
|
|
}
|
|
|
|
// Put all the entries in the block on the free list.
|
|
void InitNextPointers()
|
|
{
|
|
for (uint32_t i = 1; i < ArrayLength(mEntries); ++i) {
|
|
mEntries[i - 1].mNextInFreeList =
|
|
(nsPurpleBufferEntry*)(uintptr_t(mEntries + i) | 1);
|
|
}
|
|
mEntries[ArrayLength(mEntries) - 1].mNextInFreeList =
|
|
(nsPurpleBufferEntry*)1;
|
|
}
|
|
|
|
template<class PurpleVisitor>
|
|
void VisitEntries(nsPurpleBuffer& aBuffer, PurpleVisitor& aVisitor)
|
|
{
|
|
nsPurpleBufferEntry* eEnd = ArrayEnd(mEntries);
|
|
for (nsPurpleBufferEntry* e = mEntries; e != eEnd; ++e) {
|
|
MOZ_ASSERT(e->mObject, "There should be no null mObject when we iterate over the purple buffer");
|
|
if (!(uintptr_t(e->mObject) & uintptr_t(1)) && e->mObject) {
|
|
aVisitor.Visit(aBuffer, e);
|
|
}
|
|
}
|
|
}
|
|
};
|
|
// This class wraps a linked list of the elements in the purple
|
|
// buffer.
|
|
|
|
uint32_t mCount;
|
|
PurpleBlock mFirstBlock;
|
|
nsPurpleBufferEntry* mFreeList;
|
|
|
|
public:
|
|
nsPurpleBuffer()
|
|
{
|
|
InitBlocks();
|
|
}
|
|
|
|
~nsPurpleBuffer()
|
|
{
|
|
FreeBlocks();
|
|
}
|
|
|
|
template<class PurpleVisitor>
|
|
void VisitEntries(PurpleVisitor& aVisitor)
|
|
{
|
|
for (PurpleBlock* b = &mFirstBlock; b; b = b->mNext) {
|
|
b->VisitEntries(*this, aVisitor);
|
|
}
|
|
}
|
|
|
|
void InitBlocks()
|
|
{
|
|
mCount = 0;
|
|
mFreeList = mFirstBlock.mEntries;
|
|
}
|
|
|
|
void FreeBlocks()
|
|
{
|
|
if (mCount > 0) {
|
|
UnmarkRemainingPurple(&mFirstBlock);
|
|
}
|
|
PurpleBlock* b = mFirstBlock.mNext;
|
|
while (b) {
|
|
if (mCount > 0) {
|
|
UnmarkRemainingPurple(b);
|
|
}
|
|
PurpleBlock* next = b->mNext;
|
|
delete b;
|
|
b = next;
|
|
}
|
|
mFirstBlock.mNext = nullptr;
|
|
}
|
|
|
|
struct UnmarkRemainingPurpleVisitor
|
|
{
|
|
void
|
|
Visit(nsPurpleBuffer& aBuffer, nsPurpleBufferEntry* aEntry)
|
|
{
|
|
if (aEntry->mRefCnt) {
|
|
aEntry->mRefCnt->RemoveFromPurpleBuffer();
|
|
aEntry->mRefCnt = nullptr;
|
|
}
|
|
aEntry->mObject = nullptr;
|
|
--aBuffer.mCount;
|
|
}
|
|
};
|
|
|
|
void UnmarkRemainingPurple(PurpleBlock* aBlock)
|
|
{
|
|
UnmarkRemainingPurpleVisitor visitor;
|
|
aBlock->VisitEntries(*this, visitor);
|
|
}
|
|
|
|
void SelectPointers(CCGraphBuilder& aBuilder);
|
|
|
|
// RemoveSkippable removes entries from the purple buffer synchronously
|
|
// (1) if aAsyncSnowWhiteFreeing is false and nsPurpleBufferEntry::mRefCnt is 0 or
|
|
// (2) if the object's nsXPCOMCycleCollectionParticipant::CanSkip() returns true or
|
|
// (3) if nsPurpleBufferEntry::mRefCnt->IsPurple() is false.
|
|
// (4) If removeChildlessNodes is true, then any nodes in the purple buffer
|
|
// that will have no children in the cycle collector graph will also be
|
|
// removed. CanSkip() may be run on these children.
|
|
void RemoveSkippable(nsCycleCollector* aCollector,
|
|
bool aRemoveChildlessNodes,
|
|
bool aAsyncSnowWhiteFreeing,
|
|
CC_ForgetSkippableCallback aCb);
|
|
|
|
MOZ_ALWAYS_INLINE nsPurpleBufferEntry* NewEntry()
|
|
{
|
|
if (MOZ_UNLIKELY(!mFreeList)) {
|
|
PurpleBlock* b = new PurpleBlock;
|
|
mFreeList = b->mEntries;
|
|
|
|
// Add the new block as the second block in the list.
|
|
b->mNext = mFirstBlock.mNext;
|
|
mFirstBlock.mNext = b;
|
|
}
|
|
|
|
nsPurpleBufferEntry* e = mFreeList;
|
|
mFreeList = (nsPurpleBufferEntry*)
|
|
(uintptr_t(mFreeList->mNextInFreeList) & ~uintptr_t(1));
|
|
return e;
|
|
}
|
|
|
|
MOZ_ALWAYS_INLINE void Put(void* aObject, nsCycleCollectionParticipant* aCp,
|
|
nsCycleCollectingAutoRefCnt* aRefCnt)
|
|
{
|
|
nsPurpleBufferEntry* e = NewEntry();
|
|
|
|
++mCount;
|
|
|
|
e->mObject = aObject;
|
|
e->mRefCnt = aRefCnt;
|
|
e->mParticipant = aCp;
|
|
}
|
|
|
|
void Remove(nsPurpleBufferEntry* aEntry)
|
|
{
|
|
MOZ_ASSERT(mCount != 0, "must have entries");
|
|
|
|
if (aEntry->mRefCnt) {
|
|
aEntry->mRefCnt->RemoveFromPurpleBuffer();
|
|
aEntry->mRefCnt = nullptr;
|
|
}
|
|
aEntry->mNextInFreeList =
|
|
(nsPurpleBufferEntry*)(uintptr_t(mFreeList) | uintptr_t(1));
|
|
mFreeList = aEntry;
|
|
|
|
--mCount;
|
|
}
|
|
|
|
uint32_t Count() const
|
|
{
|
|
return mCount;
|
|
}
|
|
|
|
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
|
|
{
|
|
size_t n = 0;
|
|
|
|
// Don't measure mFirstBlock because it's within |this|.
|
|
const PurpleBlock* block = mFirstBlock.mNext;
|
|
while (block) {
|
|
n += aMallocSizeOf(block);
|
|
block = block->mNext;
|
|
}
|
|
|
|
// mFreeList is deliberately not measured because it points into
|
|
// the purple buffer, which is within mFirstBlock and thus within |this|.
|
|
//
|
|
// We also don't measure the things pointed to by mEntries[] because
|
|
// those pointers are non-owning.
|
|
|
|
return n;
|
|
}
|
|
};
|
|
|
|
static bool
|
|
AddPurpleRoot(CCGraphBuilder& aBuilder, void* aRoot,
|
|
nsCycleCollectionParticipant* aParti);
|
|
|
|
struct SelectPointersVisitor
|
|
{
|
|
explicit SelectPointersVisitor(CCGraphBuilder& aBuilder)
|
|
: mBuilder(aBuilder)
|
|
{
|
|
}
|
|
|
|
void
|
|
Visit(nsPurpleBuffer& aBuffer, nsPurpleBufferEntry* aEntry)
|
|
{
|
|
MOZ_ASSERT(aEntry->mObject, "Null object in purple buffer");
|
|
MOZ_ASSERT(aEntry->mRefCnt->get() != 0,
|
|
"SelectPointersVisitor: snow-white object in the purple buffer");
|
|
if (!aEntry->mRefCnt->IsPurple() ||
|
|
AddPurpleRoot(mBuilder, aEntry->mObject, aEntry->mParticipant)) {
|
|
aBuffer.Remove(aEntry);
|
|
}
|
|
}
|
|
|
|
private:
|
|
CCGraphBuilder& mBuilder;
|
|
};
|
|
|
|
void
|
|
nsPurpleBuffer::SelectPointers(CCGraphBuilder& aBuilder)
|
|
{
|
|
SelectPointersVisitor visitor(aBuilder);
|
|
VisitEntries(visitor);
|
|
|
|
NS_ASSERTION(mCount == 0, "AddPurpleRoot failed");
|
|
if (mCount == 0) {
|
|
FreeBlocks();
|
|
InitBlocks();
|
|
mFirstBlock.InitNextPointers();
|
|
}
|
|
}
|
|
|
|
enum ccPhase
|
|
{
|
|
IdlePhase,
|
|
GraphBuildingPhase,
|
|
ScanAndCollectWhitePhase,
|
|
CleanupPhase
|
|
};
|
|
|
|
enum ccType
|
|
{
|
|
SliceCC, /* If a CC is in progress, continue it. Otherwise, start a new one. */
|
|
ManualCC, /* Explicitly triggered. */
|
|
ShutdownCC /* Shutdown CC, used for finding leaks. */
|
|
};
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// Top level structure for the cycle collector.
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
using js::SliceBudget;
|
|
|
|
class JSPurpleBuffer;
|
|
|
|
class nsCycleCollector : public nsIMemoryReporter
|
|
{
|
|
public:
|
|
NS_DECL_ISUPPORTS
|
|
NS_DECL_NSIMEMORYREPORTER
|
|
|
|
private:
|
|
bool mActivelyCollecting;
|
|
bool mFreeingSnowWhite;
|
|
// mScanInProgress should be false when we're collecting white objects.
|
|
bool mScanInProgress;
|
|
CycleCollectorResults mResults;
|
|
TimeStamp mCollectionStart;
|
|
|
|
CycleCollectedJSContext* mJSContext;
|
|
|
|
ccPhase mIncrementalPhase;
|
|
CCGraph mGraph;
|
|
nsAutoPtr<CCGraphBuilder> mBuilder;
|
|
RefPtr<nsCycleCollectorLogger> mLogger;
|
|
|
|
#ifdef DEBUG
|
|
void* mThread;
|
|
#endif
|
|
|
|
nsCycleCollectorParams mParams;
|
|
|
|
uint32_t mWhiteNodeCount;
|
|
|
|
CC_BeforeUnlinkCallback mBeforeUnlinkCB;
|
|
CC_ForgetSkippableCallback mForgetSkippableCB;
|
|
|
|
nsPurpleBuffer mPurpleBuf;
|
|
|
|
uint32_t mUnmergedNeeded;
|
|
uint32_t mMergedInARow;
|
|
|
|
RefPtr<JSPurpleBuffer> mJSPurpleBuffer;
|
|
|
|
private:
|
|
virtual ~nsCycleCollector();
|
|
|
|
public:
|
|
nsCycleCollector();
|
|
|
|
void RegisterJSContext(CycleCollectedJSContext* aJSContext);
|
|
void ForgetJSContext();
|
|
|
|
void SetBeforeUnlinkCallback(CC_BeforeUnlinkCallback aBeforeUnlinkCB)
|
|
{
|
|
CheckThreadSafety();
|
|
mBeforeUnlinkCB = aBeforeUnlinkCB;
|
|
}
|
|
|
|
void SetForgetSkippableCallback(CC_ForgetSkippableCallback aForgetSkippableCB)
|
|
{
|
|
CheckThreadSafety();
|
|
mForgetSkippableCB = aForgetSkippableCB;
|
|
}
|
|
|
|
void Suspect(void* aPtr, nsCycleCollectionParticipant* aCp,
|
|
nsCycleCollectingAutoRefCnt* aRefCnt);
|
|
uint32_t SuspectedCount();
|
|
void ForgetSkippable(bool aRemoveChildlessNodes, bool aAsyncSnowWhiteFreeing);
|
|
bool FreeSnowWhite(bool aUntilNoSWInPurpleBuffer);
|
|
|
|
// This method assumes its argument is already canonicalized.
|
|
void RemoveObjectFromGraph(void* aPtr);
|
|
|
|
void PrepareForGarbageCollection();
|
|
void FinishAnyCurrentCollection();
|
|
|
|
bool Collect(ccType aCCType,
|
|
SliceBudget& aBudget,
|
|
nsICycleCollectorListener* aManualListener,
|
|
bool aPreferShorterSlices = false);
|
|
void Shutdown(bool aDoCollect);
|
|
|
|
bool IsIdle() const { return mIncrementalPhase == IdlePhase; }
|
|
|
|
void SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
|
|
size_t* aObjectSize,
|
|
size_t* aGraphSize,
|
|
size_t* aPurpleBufferSize) const;
|
|
|
|
JSPurpleBuffer* GetJSPurpleBuffer();
|
|
|
|
CycleCollectedJSContext* Context() { return mJSContext; }
|
|
|
|
private:
|
|
void CheckThreadSafety();
|
|
void ShutdownCollect();
|
|
|
|
void FixGrayBits(bool aForceGC, TimeLog& aTimeLog);
|
|
bool IsIncrementalGCInProgress();
|
|
void FinishAnyIncrementalGCInProgress();
|
|
bool ShouldMergeZones(ccType aCCType);
|
|
|
|
void BeginCollection(ccType aCCType, nsICycleCollectorListener* aManualListener);
|
|
void MarkRoots(SliceBudget& aBudget);
|
|
void ScanRoots(bool aFullySynchGraphBuild);
|
|
void ScanIncrementalRoots();
|
|
void ScanWhiteNodes(bool aFullySynchGraphBuild);
|
|
void ScanBlackNodes();
|
|
void ScanWeakMaps();
|
|
|
|
// returns whether anything was collected
|
|
bool CollectWhite();
|
|
|
|
void CleanupAfterCollection();
|
|
};
|
|
|
|
NS_IMPL_ISUPPORTS(nsCycleCollector, nsIMemoryReporter)
|
|
|
|
/**
|
|
* GraphWalker is templatized over a Visitor class that must provide
|
|
* the following two methods:
|
|
*
|
|
* bool ShouldVisitNode(PtrInfo const *pi);
|
|
* void VisitNode(PtrInfo *pi);
|
|
*/
|
|
template<class Visitor>
|
|
class GraphWalker
|
|
{
|
|
private:
|
|
Visitor mVisitor;
|
|
|
|
void DoWalk(nsDeque& aQueue);
|
|
|
|
void CheckedPush(nsDeque& aQueue, PtrInfo* aPi)
|
|
{
|
|
if (!aPi) {
|
|
MOZ_CRASH();
|
|
}
|
|
if (!aQueue.Push(aPi, fallible)) {
|
|
mVisitor.Failed();
|
|
}
|
|
}
|
|
|
|
public:
|
|
void Walk(PtrInfo* aPi);
|
|
void WalkFromRoots(CCGraph& aGraph);
|
|
// copy-constructing the visitor should be cheap, and less
|
|
// indirection than using a reference
|
|
explicit GraphWalker(const Visitor aVisitor) : mVisitor(aVisitor)
|
|
{
|
|
}
|
|
};
|
|
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// The static collector struct
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
struct CollectorData
|
|
{
|
|
RefPtr<nsCycleCollector> mCollector;
|
|
CycleCollectedJSContext* mContext;
|
|
};
|
|
|
|
static MOZ_THREAD_LOCAL(CollectorData*) sCollectorData;
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// Utility functions
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
static inline void
|
|
ToParticipant(nsISupports* aPtr, nsXPCOMCycleCollectionParticipant** aCp)
|
|
{
|
|
// We use QI to move from an nsISupports to an
|
|
// nsXPCOMCycleCollectionParticipant, which is a per-class singleton helper
|
|
// object that implements traversal and unlinking logic for the nsISupports
|
|
// in question.
|
|
*aCp = nullptr;
|
|
CallQueryInterface(aPtr, aCp);
|
|
}
|
|
|
|
template<class Visitor>
|
|
MOZ_NEVER_INLINE void
|
|
GraphWalker<Visitor>::Walk(PtrInfo* aPi)
|
|
{
|
|
nsDeque queue;
|
|
CheckedPush(queue, aPi);
|
|
DoWalk(queue);
|
|
}
|
|
|
|
template<class Visitor>
|
|
MOZ_NEVER_INLINE void
|
|
GraphWalker<Visitor>::WalkFromRoots(CCGraph& aGraph)
|
|
{
|
|
nsDeque queue;
|
|
NodePool::Enumerator etor(aGraph.mNodes);
|
|
for (uint32_t i = 0; i < aGraph.mRootCount; ++i) {
|
|
CheckedPush(queue, etor.GetNext());
|
|
}
|
|
DoWalk(queue);
|
|
}
|
|
|
|
template<class Visitor>
|
|
MOZ_NEVER_INLINE void
|
|
GraphWalker<Visitor>::DoWalk(nsDeque& aQueue)
|
|
{
|
|
// Use a aQueue to match the breadth-first traversal used when we
|
|
// built the graph, for hopefully-better locality.
|
|
while (aQueue.GetSize() > 0) {
|
|
PtrInfo* pi = static_cast<PtrInfo*>(aQueue.PopFront());
|
|
|
|
if (pi->WasTraversed() && mVisitor.ShouldVisitNode(pi)) {
|
|
mVisitor.VisitNode(pi);
|
|
for (EdgePool::Iterator child = pi->FirstChild(),
|
|
child_end = pi->LastChild();
|
|
child != child_end; ++child) {
|
|
CheckedPush(aQueue, *child);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
struct CCGraphDescriber : public LinkedListElement<CCGraphDescriber>
|
|
{
|
|
CCGraphDescriber()
|
|
: mAddress("0x"), mCnt(0), mType(eUnknown)
|
|
{
|
|
}
|
|
|
|
enum Type
|
|
{
|
|
eRefCountedObject,
|
|
eGCedObject,
|
|
eGCMarkedObject,
|
|
eEdge,
|
|
eRoot,
|
|
eGarbage,
|
|
eUnknown
|
|
};
|
|
|
|
nsCString mAddress;
|
|
nsCString mName;
|
|
nsCString mCompartmentOrToAddress;
|
|
uint32_t mCnt;
|
|
Type mType;
|
|
};
|
|
|
|
class LogStringMessageAsync : public CancelableRunnable
|
|
{
|
|
public:
|
|
explicit LogStringMessageAsync(const nsAString& aMsg) : mMsg(aMsg)
|
|
{}
|
|
|
|
NS_IMETHOD Run() override
|
|
{
|
|
nsCOMPtr<nsIConsoleService> cs =
|
|
do_GetService(NS_CONSOLESERVICE_CONTRACTID);
|
|
if (cs) {
|
|
cs->LogStringMessage(mMsg.get());
|
|
}
|
|
return NS_OK;
|
|
}
|
|
|
|
private:
|
|
nsString mMsg;
|
|
};
|
|
|
|
class nsCycleCollectorLogSinkToFile final : public nsICycleCollectorLogSink
|
|
{
|
|
public:
|
|
NS_DECL_ISUPPORTS
|
|
|
|
nsCycleCollectorLogSinkToFile() :
|
|
mProcessIdentifier(base::GetCurrentProcId()),
|
|
mGCLog("gc-edges"), mCCLog("cc-edges")
|
|
{
|
|
}
|
|
|
|
NS_IMETHOD GetFilenameIdentifier(nsAString& aIdentifier) override
|
|
{
|
|
aIdentifier = mFilenameIdentifier;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD SetFilenameIdentifier(const nsAString& aIdentifier) override
|
|
{
|
|
mFilenameIdentifier = aIdentifier;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD GetProcessIdentifier(int32_t* aIdentifier) override
|
|
{
|
|
*aIdentifier = mProcessIdentifier;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD SetProcessIdentifier(int32_t aIdentifier) override
|
|
{
|
|
mProcessIdentifier = aIdentifier;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD GetGcLog(nsIFile** aPath) override
|
|
{
|
|
NS_IF_ADDREF(*aPath = mGCLog.mFile);
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD GetCcLog(nsIFile** aPath) override
|
|
{
|
|
NS_IF_ADDREF(*aPath = mCCLog.mFile);
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD Open(FILE** aGCLog, FILE** aCCLog) override
|
|
{
|
|
nsresult rv;
|
|
|
|
if (mGCLog.mStream || mCCLog.mStream) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
|
|
rv = OpenLog(&mGCLog);
|
|
NS_ENSURE_SUCCESS(rv, rv);
|
|
*aGCLog = mGCLog.mStream;
|
|
|
|
rv = OpenLog(&mCCLog);
|
|
NS_ENSURE_SUCCESS(rv, rv);
|
|
*aCCLog = mCCLog.mStream;
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD CloseGCLog() override
|
|
{
|
|
if (!mGCLog.mStream) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
CloseLog(&mGCLog, NS_LITERAL_STRING("Garbage"));
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD CloseCCLog() override
|
|
{
|
|
if (!mCCLog.mStream) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
CloseLog(&mCCLog, NS_LITERAL_STRING("Cycle"));
|
|
return NS_OK;
|
|
}
|
|
|
|
private:
|
|
~nsCycleCollectorLogSinkToFile()
|
|
{
|
|
if (mGCLog.mStream) {
|
|
MozillaUnRegisterDebugFILE(mGCLog.mStream);
|
|
fclose(mGCLog.mStream);
|
|
}
|
|
if (mCCLog.mStream) {
|
|
MozillaUnRegisterDebugFILE(mCCLog.mStream);
|
|
fclose(mCCLog.mStream);
|
|
}
|
|
}
|
|
|
|
struct FileInfo
|
|
{
|
|
const char* const mPrefix;
|
|
nsCOMPtr<nsIFile> mFile;
|
|
FILE* mStream;
|
|
|
|
explicit FileInfo(const char* aPrefix) : mPrefix(aPrefix), mStream(nullptr) { }
|
|
};
|
|
|
|
/**
|
|
* Create a new file named something like aPrefix.$PID.$IDENTIFIER.log in
|
|
* $MOZ_CC_LOG_DIRECTORY or in the system's temp directory. No existing
|
|
* file will be overwritten; if aPrefix.$PID.$IDENTIFIER.log exists, we'll
|
|
* try a file named something like aPrefix.$PID.$IDENTIFIER-1.log, and so
|
|
* on.
|
|
*/
|
|
already_AddRefed<nsIFile> CreateTempFile(const char* aPrefix)
|
|
{
|
|
nsPrintfCString filename("%s.%d%s%s.log",
|
|
aPrefix,
|
|
mProcessIdentifier,
|
|
mFilenameIdentifier.IsEmpty() ? "" : ".",
|
|
NS_ConvertUTF16toUTF8(mFilenameIdentifier).get());
|
|
|
|
// Get the log directory either from $MOZ_CC_LOG_DIRECTORY or from
|
|
// the fallback directories in OpenTempFile. We don't use an nsCOMPtr
|
|
// here because OpenTempFile uses an in/out param and getter_AddRefs
|
|
// wouldn't work.
|
|
nsIFile* logFile = nullptr;
|
|
if (char* env = PR_GetEnv("MOZ_CC_LOG_DIRECTORY")) {
|
|
NS_NewNativeLocalFile(nsCString(env), /* followLinks = */ true,
|
|
&logFile);
|
|
}
|
|
|
|
// On Android or B2G, this function will open a file named
|
|
// aFilename under a memory-reporting-specific folder
|
|
// (/data/local/tmp/memory-reports). Otherwise, it will open a
|
|
// file named aFilename under "NS_OS_TEMP_DIR".
|
|
nsresult rv = nsDumpUtils::OpenTempFile(filename, &logFile,
|
|
NS_LITERAL_CSTRING("memory-reports"));
|
|
if (NS_FAILED(rv)) {
|
|
NS_IF_RELEASE(logFile);
|
|
return nullptr;
|
|
}
|
|
|
|
return dont_AddRef(logFile);
|
|
}
|
|
|
|
nsresult OpenLog(FileInfo* aLog)
|
|
{
|
|
// Initially create the log in a file starting with "incomplete-".
|
|
// We'll move the file and strip off the "incomplete-" once the dump
|
|
// completes. (We do this because we don't want scripts which poll
|
|
// the filesystem looking for GC/CC dumps to grab a file before we're
|
|
// finished writing to it.)
|
|
nsAutoCString incomplete;
|
|
incomplete += "incomplete-";
|
|
incomplete += aLog->mPrefix;
|
|
MOZ_ASSERT(!aLog->mFile);
|
|
aLog->mFile = CreateTempFile(incomplete.get());
|
|
if (NS_WARN_IF(!aLog->mFile)) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
|
|
MOZ_ASSERT(!aLog->mStream);
|
|
nsresult rv = aLog->mFile->OpenANSIFileDesc("w", &aLog->mStream);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
MozillaRegisterDebugFILE(aLog->mStream);
|
|
return NS_OK;
|
|
}
|
|
|
|
nsresult CloseLog(FileInfo* aLog, const nsAString& aCollectorKind)
|
|
{
|
|
MOZ_ASSERT(aLog->mStream);
|
|
MOZ_ASSERT(aLog->mFile);
|
|
|
|
MozillaUnRegisterDebugFILE(aLog->mStream);
|
|
fclose(aLog->mStream);
|
|
aLog->mStream = nullptr;
|
|
|
|
// Strip off "incomplete-".
|
|
nsCOMPtr<nsIFile> logFileFinalDestination =
|
|
CreateTempFile(aLog->mPrefix);
|
|
if (NS_WARN_IF(!logFileFinalDestination)) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
|
|
nsAutoString logFileFinalDestinationName;
|
|
logFileFinalDestination->GetLeafName(logFileFinalDestinationName);
|
|
if (NS_WARN_IF(logFileFinalDestinationName.IsEmpty())) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
|
|
aLog->mFile->MoveTo(/* directory */ nullptr, logFileFinalDestinationName);
|
|
|
|
// Save the file path.
|
|
aLog->mFile = logFileFinalDestination;
|
|
|
|
// Log to the error console.
|
|
nsAutoString logPath;
|
|
logFileFinalDestination->GetPath(logPath);
|
|
nsAutoString msg = aCollectorKind +
|
|
NS_LITERAL_STRING(" Collector log dumped to ") + logPath;
|
|
|
|
// We don't want any JS to run between ScanRoots and CollectWhite calls,
|
|
// and since ScanRoots calls this method, better to log the message
|
|
// asynchronously.
|
|
RefPtr<LogStringMessageAsync> log = new LogStringMessageAsync(msg);
|
|
NS_DispatchToCurrentThread(log);
|
|
return NS_OK;
|
|
}
|
|
|
|
int32_t mProcessIdentifier;
|
|
nsString mFilenameIdentifier;
|
|
FileInfo mGCLog;
|
|
FileInfo mCCLog;
|
|
};
|
|
|
|
NS_IMPL_ISUPPORTS(nsCycleCollectorLogSinkToFile, nsICycleCollectorLogSink)
|
|
|
|
|
|
class nsCycleCollectorLogger final : public nsICycleCollectorListener
|
|
{
|
|
~nsCycleCollectorLogger()
|
|
{
|
|
ClearDescribers();
|
|
}
|
|
|
|
public:
|
|
nsCycleCollectorLogger()
|
|
: mLogSink(nsCycleCollector_createLogSink())
|
|
, mWantAllTraces(false)
|
|
, mDisableLog(false)
|
|
, mWantAfterProcessing(false)
|
|
, mCCLog(nullptr)
|
|
{
|
|
}
|
|
|
|
NS_DECL_ISUPPORTS
|
|
|
|
void SetAllTraces()
|
|
{
|
|
mWantAllTraces = true;
|
|
}
|
|
|
|
bool IsAllTraces()
|
|
{
|
|
return mWantAllTraces;
|
|
}
|
|
|
|
NS_IMETHOD AllTraces(nsICycleCollectorListener** aListener) override
|
|
{
|
|
SetAllTraces();
|
|
NS_ADDREF(*aListener = this);
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD GetWantAllTraces(bool* aAllTraces) override
|
|
{
|
|
*aAllTraces = mWantAllTraces;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD GetDisableLog(bool* aDisableLog) override
|
|
{
|
|
*aDisableLog = mDisableLog;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD SetDisableLog(bool aDisableLog) override
|
|
{
|
|
mDisableLog = aDisableLog;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD GetWantAfterProcessing(bool* aWantAfterProcessing) override
|
|
{
|
|
*aWantAfterProcessing = mWantAfterProcessing;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD SetWantAfterProcessing(bool aWantAfterProcessing) override
|
|
{
|
|
mWantAfterProcessing = aWantAfterProcessing;
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD GetLogSink(nsICycleCollectorLogSink** aLogSink) override
|
|
{
|
|
NS_ADDREF(*aLogSink = mLogSink);
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHOD SetLogSink(nsICycleCollectorLogSink* aLogSink) override
|
|
{
|
|
if (!aLogSink) {
|
|
return NS_ERROR_INVALID_ARG;
|
|
}
|
|
mLogSink = aLogSink;
|
|
return NS_OK;
|
|
}
|
|
|
|
nsresult Begin()
|
|
{
|
|
nsresult rv;
|
|
|
|
mCurrentAddress.AssignLiteral("0x");
|
|
ClearDescribers();
|
|
if (mDisableLog) {
|
|
return NS_OK;
|
|
}
|
|
|
|
FILE* gcLog;
|
|
rv = mLogSink->Open(&gcLog, &mCCLog);
|
|
NS_ENSURE_SUCCESS(rv, rv);
|
|
// Dump the JS heap.
|
|
CollectorData* data = sCollectorData.get();
|
|
if (data && data->mContext) {
|
|
data->mContext->DumpJSHeap(gcLog);
|
|
}
|
|
rv = mLogSink->CloseGCLog();
|
|
NS_ENSURE_SUCCESS(rv, rv);
|
|
|
|
fprintf(mCCLog, "# WantAllTraces=%s\n", mWantAllTraces ? "true" : "false");
|
|
return NS_OK;
|
|
}
|
|
void NoteRefCountedObject(uint64_t aAddress, uint32_t aRefCount,
|
|
const char* aObjectDescription)
|
|
{
|
|
if (!mDisableLog) {
|
|
fprintf(mCCLog, "%p [rc=%u] %s\n", (void*)aAddress, aRefCount,
|
|
aObjectDescription);
|
|
}
|
|
if (mWantAfterProcessing) {
|
|
CCGraphDescriber* d = new CCGraphDescriber();
|
|
mDescribers.insertBack(d);
|
|
mCurrentAddress.AssignLiteral("0x");
|
|
mCurrentAddress.AppendInt(aAddress, 16);
|
|
d->mType = CCGraphDescriber::eRefCountedObject;
|
|
d->mAddress = mCurrentAddress;
|
|
d->mCnt = aRefCount;
|
|
d->mName.Append(aObjectDescription);
|
|
}
|
|
}
|
|
void NoteGCedObject(uint64_t aAddress, bool aMarked,
|
|
const char* aObjectDescription,
|
|
uint64_t aCompartmentAddress)
|
|
{
|
|
if (!mDisableLog) {
|
|
fprintf(mCCLog, "%p [gc%s] %s\n", (void*)aAddress,
|
|
aMarked ? ".marked" : "", aObjectDescription);
|
|
}
|
|
if (mWantAfterProcessing) {
|
|
CCGraphDescriber* d = new CCGraphDescriber();
|
|
mDescribers.insertBack(d);
|
|
mCurrentAddress.AssignLiteral("0x");
|
|
mCurrentAddress.AppendInt(aAddress, 16);
|
|
d->mType = aMarked ? CCGraphDescriber::eGCMarkedObject :
|
|
CCGraphDescriber::eGCedObject;
|
|
d->mAddress = mCurrentAddress;
|
|
d->mName.Append(aObjectDescription);
|
|
if (aCompartmentAddress) {
|
|
d->mCompartmentOrToAddress.AssignLiteral("0x");
|
|
d->mCompartmentOrToAddress.AppendInt(aCompartmentAddress, 16);
|
|
} else {
|
|
d->mCompartmentOrToAddress.SetIsVoid(true);
|
|
}
|
|
}
|
|
}
|
|
void NoteEdge(uint64_t aToAddress, const char* aEdgeName)
|
|
{
|
|
if (!mDisableLog) {
|
|
fprintf(mCCLog, "> %p %s\n", (void*)aToAddress, aEdgeName);
|
|
}
|
|
if (mWantAfterProcessing) {
|
|
CCGraphDescriber* d = new CCGraphDescriber();
|
|
mDescribers.insertBack(d);
|
|
d->mType = CCGraphDescriber::eEdge;
|
|
d->mAddress = mCurrentAddress;
|
|
d->mCompartmentOrToAddress.AssignLiteral("0x");
|
|
d->mCompartmentOrToAddress.AppendInt(aToAddress, 16);
|
|
d->mName.Append(aEdgeName);
|
|
}
|
|
}
|
|
void NoteWeakMapEntry(uint64_t aMap, uint64_t aKey,
|
|
uint64_t aKeyDelegate, uint64_t aValue)
|
|
{
|
|
if (!mDisableLog) {
|
|
fprintf(mCCLog, "WeakMapEntry map=%p key=%p keyDelegate=%p value=%p\n",
|
|
(void*)aMap, (void*)aKey, (void*)aKeyDelegate, (void*)aValue);
|
|
}
|
|
// We don't support after-processing for weak map entries.
|
|
}
|
|
void NoteIncrementalRoot(uint64_t aAddress)
|
|
{
|
|
if (!mDisableLog) {
|
|
fprintf(mCCLog, "IncrementalRoot %p\n", (void*)aAddress);
|
|
}
|
|
// We don't support after-processing for incremental roots.
|
|
}
|
|
void BeginResults()
|
|
{
|
|
if (!mDisableLog) {
|
|
fputs("==========\n", mCCLog);
|
|
}
|
|
}
|
|
void DescribeRoot(uint64_t aAddress, uint32_t aKnownEdges)
|
|
{
|
|
if (!mDisableLog) {
|
|
fprintf(mCCLog, "%p [known=%u]\n", (void*)aAddress, aKnownEdges);
|
|
}
|
|
if (mWantAfterProcessing) {
|
|
CCGraphDescriber* d = new CCGraphDescriber();
|
|
mDescribers.insertBack(d);
|
|
d->mType = CCGraphDescriber::eRoot;
|
|
d->mAddress.AppendInt(aAddress, 16);
|
|
d->mCnt = aKnownEdges;
|
|
}
|
|
}
|
|
void DescribeGarbage(uint64_t aAddress)
|
|
{
|
|
if (!mDisableLog) {
|
|
fprintf(mCCLog, "%p [garbage]\n", (void*)aAddress);
|
|
}
|
|
if (mWantAfterProcessing) {
|
|
CCGraphDescriber* d = new CCGraphDescriber();
|
|
mDescribers.insertBack(d);
|
|
d->mType = CCGraphDescriber::eGarbage;
|
|
d->mAddress.AppendInt(aAddress, 16);
|
|
}
|
|
}
|
|
void End()
|
|
{
|
|
if (!mDisableLog) {
|
|
mCCLog = nullptr;
|
|
Unused << NS_WARN_IF(NS_FAILED(mLogSink->CloseCCLog()));
|
|
}
|
|
}
|
|
NS_IMETHOD ProcessNext(nsICycleCollectorHandler* aHandler,
|
|
bool* aCanContinue) override
|
|
{
|
|
if (NS_WARN_IF(!aHandler) || NS_WARN_IF(!mWantAfterProcessing)) {
|
|
return NS_ERROR_UNEXPECTED;
|
|
}
|
|
CCGraphDescriber* d = mDescribers.popFirst();
|
|
if (d) {
|
|
switch (d->mType) {
|
|
case CCGraphDescriber::eRefCountedObject:
|
|
aHandler->NoteRefCountedObject(d->mAddress,
|
|
d->mCnt,
|
|
d->mName);
|
|
break;
|
|
case CCGraphDescriber::eGCedObject:
|
|
case CCGraphDescriber::eGCMarkedObject:
|
|
aHandler->NoteGCedObject(d->mAddress,
|
|
d->mType ==
|
|
CCGraphDescriber::eGCMarkedObject,
|
|
d->mName,
|
|
d->mCompartmentOrToAddress);
|
|
break;
|
|
case CCGraphDescriber::eEdge:
|
|
aHandler->NoteEdge(d->mAddress,
|
|
d->mCompartmentOrToAddress,
|
|
d->mName);
|
|
break;
|
|
case CCGraphDescriber::eRoot:
|
|
aHandler->DescribeRoot(d->mAddress,
|
|
d->mCnt);
|
|
break;
|
|
case CCGraphDescriber::eGarbage:
|
|
aHandler->DescribeGarbage(d->mAddress);
|
|
break;
|
|
case CCGraphDescriber::eUnknown:
|
|
NS_NOTREACHED("CCGraphDescriber::eUnknown");
|
|
break;
|
|
}
|
|
delete d;
|
|
}
|
|
if (!(*aCanContinue = !mDescribers.isEmpty())) {
|
|
mCurrentAddress.AssignLiteral("0x");
|
|
}
|
|
return NS_OK;
|
|
}
|
|
NS_IMETHOD AsLogger(nsCycleCollectorLogger** aRetVal) override
|
|
{
|
|
RefPtr<nsCycleCollectorLogger> rval = this;
|
|
rval.forget(aRetVal);
|
|
return NS_OK;
|
|
}
|
|
private:
|
|
void ClearDescribers()
|
|
{
|
|
CCGraphDescriber* d;
|
|
while ((d = mDescribers.popFirst())) {
|
|
delete d;
|
|
}
|
|
}
|
|
|
|
nsCOMPtr<nsICycleCollectorLogSink> mLogSink;
|
|
bool mWantAllTraces;
|
|
bool mDisableLog;
|
|
bool mWantAfterProcessing;
|
|
nsCString mCurrentAddress;
|
|
mozilla::LinkedList<CCGraphDescriber> mDescribers;
|
|
FILE* mCCLog;
|
|
};
|
|
|
|
NS_IMPL_ISUPPORTS(nsCycleCollectorLogger, nsICycleCollectorListener)
|
|
|
|
nsresult
|
|
nsCycleCollectorLoggerConstructor(nsISupports* aOuter,
|
|
const nsIID& aIID,
|
|
void** aInstancePtr)
|
|
{
|
|
if (NS_WARN_IF(aOuter)) {
|
|
return NS_ERROR_NO_AGGREGATION;
|
|
}
|
|
|
|
nsISupports* logger = new nsCycleCollectorLogger();
|
|
|
|
return logger->QueryInterface(aIID, aInstancePtr);
|
|
}
|
|
|
|
static bool
|
|
GCThingIsGrayCCThing(JS::GCCellPtr thing)
|
|
{
|
|
return AddToCCKind(thing.kind()) &&
|
|
JS::GCThingIsMarkedGray(thing);
|
|
}
|
|
|
|
static bool
|
|
ValueIsGrayCCThing(const JS::Value& value)
|
|
{
|
|
return AddToCCKind(value.traceKind()) &&
|
|
JS::GCThingIsMarkedGray(value.toGCCellPtr());
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// Bacon & Rajan's |MarkRoots| routine.
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
class CCGraphBuilder final : public nsCycleCollectionTraversalCallback,
|
|
public nsCycleCollectionNoteRootCallback
|
|
{
|
|
private:
|
|
CCGraph& mGraph;
|
|
CycleCollectorResults& mResults;
|
|
NodePool::Builder mNodeBuilder;
|
|
EdgePool::Builder mEdgeBuilder;
|
|
MOZ_INIT_OUTSIDE_CTOR PtrInfo* mCurrPi;
|
|
nsCycleCollectionParticipant* mJSParticipant;
|
|
nsCycleCollectionParticipant* mJSZoneParticipant;
|
|
nsCString mNextEdgeName;
|
|
RefPtr<nsCycleCollectorLogger> mLogger;
|
|
bool mMergeZones;
|
|
nsAutoPtr<NodePool::Enumerator> mCurrNode;
|
|
|
|
public:
|
|
CCGraphBuilder(CCGraph& aGraph,
|
|
CycleCollectorResults& aResults,
|
|
CycleCollectedJSContext* aJSContext,
|
|
nsCycleCollectorLogger* aLogger,
|
|
bool aMergeZones);
|
|
virtual ~CCGraphBuilder();
|
|
|
|
bool WantAllTraces() const
|
|
{
|
|
return nsCycleCollectionNoteRootCallback::WantAllTraces();
|
|
}
|
|
|
|
bool AddPurpleRoot(void* aRoot, nsCycleCollectionParticipant* aParti);
|
|
|
|
// This is called when all roots have been added to the graph, to prepare for BuildGraph().
|
|
void DoneAddingRoots();
|
|
|
|
// Do some work traversing nodes in the graph. Returns true if this graph building is finished.
|
|
bool BuildGraph(SliceBudget& aBudget);
|
|
|
|
private:
|
|
PtrInfo* AddNode(void* aPtr, nsCycleCollectionParticipant* aParticipant);
|
|
PtrInfo* AddWeakMapNode(JS::GCCellPtr aThing);
|
|
PtrInfo* AddWeakMapNode(JSObject* aObject);
|
|
|
|
void SetFirstChild()
|
|
{
|
|
mCurrPi->SetFirstChild(mEdgeBuilder.Mark());
|
|
}
|
|
|
|
void SetLastChild()
|
|
{
|
|
mCurrPi->SetLastChild(mEdgeBuilder.Mark());
|
|
}
|
|
|
|
public:
|
|
// nsCycleCollectionNoteRootCallback methods.
|
|
NS_IMETHOD_(void) NoteXPCOMRoot(nsISupports* aRoot);
|
|
NS_IMETHOD_(void) NoteJSRoot(JSObject* aRoot);
|
|
NS_IMETHOD_(void) NoteNativeRoot(void* aRoot,
|
|
nsCycleCollectionParticipant* aParticipant);
|
|
NS_IMETHOD_(void) NoteWeakMapping(JSObject* aMap, JS::GCCellPtr aKey,
|
|
JSObject* aKdelegate, JS::GCCellPtr aVal);
|
|
|
|
// nsCycleCollectionTraversalCallback methods.
|
|
NS_IMETHOD_(void) DescribeRefCountedNode(nsrefcnt aRefCount,
|
|
const char* aObjName);
|
|
NS_IMETHOD_(void) DescribeGCedNode(bool aIsMarked, const char* aObjName,
|
|
uint64_t aCompartmentAddress);
|
|
|
|
NS_IMETHOD_(void) NoteXPCOMChild(nsISupports* aChild);
|
|
NS_IMETHOD_(void) NoteJSChild(const JS::GCCellPtr& aThing);
|
|
NS_IMETHOD_(void) NoteNativeChild(void* aChild,
|
|
nsCycleCollectionParticipant* aParticipant);
|
|
NS_IMETHOD_(void) NoteNextEdgeName(const char* aName);
|
|
|
|
private:
|
|
void NoteJSChild(JS::GCCellPtr aChild);
|
|
|
|
NS_IMETHOD_(void) NoteRoot(void* aRoot,
|
|
nsCycleCollectionParticipant* aParticipant)
|
|
{
|
|
MOZ_ASSERT(aRoot);
|
|
MOZ_ASSERT(aParticipant);
|
|
|
|
if (!aParticipant->CanSkipInCC(aRoot) || MOZ_UNLIKELY(WantAllTraces())) {
|
|
AddNode(aRoot, aParticipant);
|
|
}
|
|
}
|
|
|
|
NS_IMETHOD_(void) NoteChild(void* aChild, nsCycleCollectionParticipant* aCp,
|
|
nsCString& aEdgeName)
|
|
{
|
|
PtrInfo* childPi = AddNode(aChild, aCp);
|
|
if (!childPi) {
|
|
return;
|
|
}
|
|
mEdgeBuilder.Add(childPi);
|
|
if (mLogger) {
|
|
mLogger->NoteEdge((uint64_t)aChild, aEdgeName.get());
|
|
}
|
|
++childPi->mInternalRefs;
|
|
}
|
|
|
|
JS::Zone* MergeZone(JS::GCCellPtr aGcthing)
|
|
{
|
|
if (!mMergeZones) {
|
|
return nullptr;
|
|
}
|
|
JS::Zone* zone = JS::GetTenuredGCThingZone(aGcthing);
|
|
if (js::IsSystemZone(zone)) {
|
|
return nullptr;
|
|
}
|
|
return zone;
|
|
}
|
|
};
|
|
|
|
CCGraphBuilder::CCGraphBuilder(CCGraph& aGraph,
|
|
CycleCollectorResults& aResults,
|
|
CycleCollectedJSContext* aJSContext,
|
|
nsCycleCollectorLogger* aLogger,
|
|
bool aMergeZones)
|
|
: mGraph(aGraph)
|
|
, mResults(aResults)
|
|
, mNodeBuilder(aGraph.mNodes)
|
|
, mEdgeBuilder(aGraph.mEdges)
|
|
, mJSParticipant(nullptr)
|
|
, mJSZoneParticipant(nullptr)
|
|
, mLogger(aLogger)
|
|
, mMergeZones(aMergeZones)
|
|
{
|
|
if (aJSContext) {
|
|
mJSParticipant = aJSContext->GCThingParticipant();
|
|
mJSZoneParticipant = aJSContext->ZoneParticipant();
|
|
}
|
|
|
|
if (mLogger) {
|
|
mFlags |= nsCycleCollectionTraversalCallback::WANT_DEBUG_INFO;
|
|
if (mLogger->IsAllTraces()) {
|
|
mFlags |= nsCycleCollectionTraversalCallback::WANT_ALL_TRACES;
|
|
mWantAllTraces = true; // for nsCycleCollectionNoteRootCallback
|
|
}
|
|
}
|
|
|
|
mMergeZones = mMergeZones && MOZ_LIKELY(!WantAllTraces());
|
|
|
|
MOZ_ASSERT(nsCycleCollectionNoteRootCallback::WantAllTraces() ==
|
|
nsCycleCollectionTraversalCallback::WantAllTraces());
|
|
}
|
|
|
|
CCGraphBuilder::~CCGraphBuilder()
|
|
{
|
|
}
|
|
|
|
PtrInfo*
|
|
CCGraphBuilder::AddNode(void* aPtr, nsCycleCollectionParticipant* aParticipant)
|
|
{
|
|
PtrToNodeEntry* e = mGraph.AddNodeToMap(aPtr);
|
|
if (!e) {
|
|
return nullptr;
|
|
}
|
|
|
|
PtrInfo* result;
|
|
if (!e->mNode) {
|
|
// New entry.
|
|
result = mNodeBuilder.Add(aPtr, aParticipant);
|
|
if (!result) {
|
|
return nullptr;
|
|
}
|
|
|
|
e->mNode = result;
|
|
NS_ASSERTION(result, "mNodeBuilder.Add returned null");
|
|
} else {
|
|
result = e->mNode;
|
|
MOZ_ASSERT(result->mParticipant == aParticipant,
|
|
"nsCycleCollectionParticipant shouldn't change!");
|
|
}
|
|
return result;
|
|
}
|
|
|
|
bool
|
|
CCGraphBuilder::AddPurpleRoot(void* aRoot, nsCycleCollectionParticipant* aParti)
|
|
{
|
|
CanonicalizeParticipant(&aRoot, &aParti);
|
|
|
|
if (WantAllTraces() || !aParti->CanSkipInCC(aRoot)) {
|
|
PtrInfo* pinfo = AddNode(aRoot, aParti);
|
|
if (!pinfo) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void
|
|
CCGraphBuilder::DoneAddingRoots()
|
|
{
|
|
// We've finished adding roots, and everything in the graph is a root.
|
|
mGraph.mRootCount = mGraph.MapCount();
|
|
|
|
mCurrNode = new NodePool::Enumerator(mGraph.mNodes);
|
|
}
|
|
|
|
MOZ_NEVER_INLINE bool
|
|
CCGraphBuilder::BuildGraph(SliceBudget& aBudget)
|
|
{
|
|
const intptr_t kNumNodesBetweenTimeChecks = 1000;
|
|
const intptr_t kStep = SliceBudget::CounterReset / kNumNodesBetweenTimeChecks;
|
|
|
|
MOZ_ASSERT(mCurrNode);
|
|
|
|
while (!aBudget.isOverBudget() && !mCurrNode->IsDone()) {
|
|
PtrInfo* pi = mCurrNode->GetNext();
|
|
if (!pi) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
mCurrPi = pi;
|
|
|
|
// We need to call SetFirstChild() even on deleted nodes, to set their
|
|
// firstChild() that may be read by a prior non-deleted neighbor.
|
|
SetFirstChild();
|
|
|
|
if (pi->mParticipant) {
|
|
nsresult rv = pi->mParticipant->TraverseNativeAndJS(pi->mPointer, *this);
|
|
MOZ_RELEASE_ASSERT(!NS_FAILED(rv), "Cycle collector Traverse method failed");
|
|
}
|
|
|
|
if (mCurrNode->AtBlockEnd()) {
|
|
SetLastChild();
|
|
}
|
|
|
|
aBudget.step(kStep);
|
|
}
|
|
|
|
if (!mCurrNode->IsDone()) {
|
|
return false;
|
|
}
|
|
|
|
if (mGraph.mRootCount > 0) {
|
|
SetLastChild();
|
|
}
|
|
|
|
mCurrNode = nullptr;
|
|
|
|
return true;
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteXPCOMRoot(nsISupports* aRoot)
|
|
{
|
|
aRoot = CanonicalizeXPCOMParticipant(aRoot);
|
|
NS_ASSERTION(aRoot,
|
|
"Don't add objects that don't participate in collection!");
|
|
|
|
nsXPCOMCycleCollectionParticipant* cp;
|
|
ToParticipant(aRoot, &cp);
|
|
|
|
NoteRoot(aRoot, cp);
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteJSRoot(JSObject* aRoot)
|
|
{
|
|
if (JS::Zone* zone = MergeZone(JS::GCCellPtr(aRoot))) {
|
|
NoteRoot(zone, mJSZoneParticipant);
|
|
} else {
|
|
NoteRoot(aRoot, mJSParticipant);
|
|
}
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteNativeRoot(void* aRoot,
|
|
nsCycleCollectionParticipant* aParticipant)
|
|
{
|
|
NoteRoot(aRoot, aParticipant);
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::DescribeRefCountedNode(nsrefcnt aRefCount, const char* aObjName)
|
|
{
|
|
MOZ_RELEASE_ASSERT(aRefCount != 0, "CCed refcounted object has zero refcount");
|
|
MOZ_RELEASE_ASSERT(aRefCount != UINT32_MAX, "CCed refcounted object has overflowing refcount");
|
|
|
|
mResults.mVisitedRefCounted++;
|
|
|
|
if (mLogger) {
|
|
mLogger->NoteRefCountedObject((uint64_t)mCurrPi->mPointer, aRefCount,
|
|
aObjName);
|
|
}
|
|
|
|
mCurrPi->mRefCount = aRefCount;
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::DescribeGCedNode(bool aIsMarked, const char* aObjName,
|
|
uint64_t aCompartmentAddress)
|
|
{
|
|
uint32_t refCount = aIsMarked ? UINT32_MAX : 0;
|
|
mResults.mVisitedGCed++;
|
|
|
|
if (mLogger) {
|
|
mLogger->NoteGCedObject((uint64_t)mCurrPi->mPointer, aIsMarked,
|
|
aObjName, aCompartmentAddress);
|
|
}
|
|
|
|
mCurrPi->mRefCount = refCount;
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteXPCOMChild(nsISupports* aChild)
|
|
{
|
|
nsCString edgeName;
|
|
if (WantDebugInfo()) {
|
|
edgeName.Assign(mNextEdgeName);
|
|
mNextEdgeName.Truncate();
|
|
}
|
|
if (!aChild || !(aChild = CanonicalizeXPCOMParticipant(aChild))) {
|
|
return;
|
|
}
|
|
|
|
nsXPCOMCycleCollectionParticipant* cp;
|
|
ToParticipant(aChild, &cp);
|
|
if (cp && (!cp->CanSkipThis(aChild) || WantAllTraces())) {
|
|
NoteChild(aChild, cp, edgeName);
|
|
}
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteNativeChild(void* aChild,
|
|
nsCycleCollectionParticipant* aParticipant)
|
|
{
|
|
nsCString edgeName;
|
|
if (WantDebugInfo()) {
|
|
edgeName.Assign(mNextEdgeName);
|
|
mNextEdgeName.Truncate();
|
|
}
|
|
if (!aChild) {
|
|
return;
|
|
}
|
|
|
|
MOZ_ASSERT(aParticipant, "Need a nsCycleCollectionParticipant!");
|
|
if (!aParticipant->CanSkipThis(aChild) || WantAllTraces()) {
|
|
NoteChild(aChild, aParticipant, edgeName);
|
|
}
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteJSChild(const JS::GCCellPtr& aChild)
|
|
{
|
|
if (!aChild) {
|
|
return;
|
|
}
|
|
|
|
nsCString edgeName;
|
|
if (MOZ_UNLIKELY(WantDebugInfo())) {
|
|
edgeName.Assign(mNextEdgeName);
|
|
mNextEdgeName.Truncate();
|
|
}
|
|
|
|
if (GCThingIsGrayCCThing(aChild) || MOZ_UNLIKELY(WantAllTraces())) {
|
|
if (JS::Zone* zone = MergeZone(aChild)) {
|
|
NoteChild(zone, mJSZoneParticipant, edgeName);
|
|
} else {
|
|
NoteChild(aChild.asCell(), mJSParticipant, edgeName);
|
|
}
|
|
}
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteNextEdgeName(const char* aName)
|
|
{
|
|
if (WantDebugInfo()) {
|
|
mNextEdgeName = aName;
|
|
}
|
|
}
|
|
|
|
PtrInfo*
|
|
CCGraphBuilder::AddWeakMapNode(JS::GCCellPtr aNode)
|
|
{
|
|
MOZ_ASSERT(aNode, "Weak map node should be non-null.");
|
|
|
|
if (!GCThingIsGrayCCThing(aNode) && !WantAllTraces()) {
|
|
return nullptr;
|
|
}
|
|
|
|
if (JS::Zone* zone = MergeZone(aNode)) {
|
|
return AddNode(zone, mJSZoneParticipant);
|
|
}
|
|
return AddNode(aNode.asCell(), mJSParticipant);
|
|
}
|
|
|
|
PtrInfo*
|
|
CCGraphBuilder::AddWeakMapNode(JSObject* aObject)
|
|
{
|
|
return AddWeakMapNode(JS::GCCellPtr(aObject));
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
CCGraphBuilder::NoteWeakMapping(JSObject* aMap, JS::GCCellPtr aKey,
|
|
JSObject* aKdelegate, JS::GCCellPtr aVal)
|
|
{
|
|
// Don't try to optimize away the entry here, as we've already attempted to
|
|
// do that in TraceWeakMapping in nsXPConnect.
|
|
WeakMapping* mapping = mGraph.mWeakMaps.AppendElement();
|
|
mapping->mMap = aMap ? AddWeakMapNode(aMap) : nullptr;
|
|
mapping->mKey = aKey ? AddWeakMapNode(aKey) : nullptr;
|
|
mapping->mKeyDelegate = aKdelegate ? AddWeakMapNode(aKdelegate) : mapping->mKey;
|
|
mapping->mVal = aVal ? AddWeakMapNode(aVal) : nullptr;
|
|
|
|
if (mLogger) {
|
|
mLogger->NoteWeakMapEntry((uint64_t)aMap, aKey ? aKey.unsafeAsInteger() : 0,
|
|
(uint64_t)aKdelegate,
|
|
aVal ? aVal.unsafeAsInteger() : 0);
|
|
}
|
|
}
|
|
|
|
static bool
|
|
AddPurpleRoot(CCGraphBuilder& aBuilder, void* aRoot,
|
|
nsCycleCollectionParticipant* aParti)
|
|
{
|
|
return aBuilder.AddPurpleRoot(aRoot, aParti);
|
|
}
|
|
|
|
// MayHaveChild() will be false after a Traverse if the object does
|
|
// not have any children the CC will visit.
|
|
class ChildFinder : public nsCycleCollectionTraversalCallback
|
|
{
|
|
public:
|
|
ChildFinder() : mMayHaveChild(false)
|
|
{
|
|
}
|
|
|
|
// The logic of the Note*Child functions must mirror that of their
|
|
// respective functions in CCGraphBuilder.
|
|
NS_IMETHOD_(void) NoteXPCOMChild(nsISupports* aChild);
|
|
NS_IMETHOD_(void) NoteNativeChild(void* aChild,
|
|
nsCycleCollectionParticipant* aHelper);
|
|
NS_IMETHOD_(void) NoteJSChild(const JS::GCCellPtr& aThing);
|
|
|
|
NS_IMETHOD_(void) DescribeRefCountedNode(nsrefcnt aRefcount,
|
|
const char* aObjname)
|
|
{
|
|
}
|
|
NS_IMETHOD_(void) DescribeGCedNode(bool aIsMarked,
|
|
const char* aObjname,
|
|
uint64_t aCompartmentAddress)
|
|
{
|
|
}
|
|
NS_IMETHOD_(void) NoteNextEdgeName(const char* aName)
|
|
{
|
|
}
|
|
bool MayHaveChild()
|
|
{
|
|
return mMayHaveChild;
|
|
}
|
|
private:
|
|
bool mMayHaveChild;
|
|
};
|
|
|
|
NS_IMETHODIMP_(void)
|
|
ChildFinder::NoteXPCOMChild(nsISupports* aChild)
|
|
{
|
|
if (!aChild || !(aChild = CanonicalizeXPCOMParticipant(aChild))) {
|
|
return;
|
|
}
|
|
nsXPCOMCycleCollectionParticipant* cp;
|
|
ToParticipant(aChild, &cp);
|
|
if (cp && !cp->CanSkip(aChild, true)) {
|
|
mMayHaveChild = true;
|
|
}
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
ChildFinder::NoteNativeChild(void* aChild,
|
|
nsCycleCollectionParticipant* aHelper)
|
|
{
|
|
if (!aChild) {
|
|
return;
|
|
}
|
|
MOZ_ASSERT(aHelper, "Native child must have a participant");
|
|
if (!aHelper->CanSkip(aChild, true)) {
|
|
mMayHaveChild = true;
|
|
}
|
|
}
|
|
|
|
NS_IMETHODIMP_(void)
|
|
ChildFinder::NoteJSChild(const JS::GCCellPtr& aChild)
|
|
{
|
|
if (aChild && JS::GCThingIsMarkedGray(aChild)) {
|
|
mMayHaveChild = true;
|
|
}
|
|
}
|
|
|
|
static bool
|
|
MayHaveChild(void* aObj, nsCycleCollectionParticipant* aCp)
|
|
{
|
|
ChildFinder cf;
|
|
aCp->TraverseNativeAndJS(aObj, cf);
|
|
return cf.MayHaveChild();
|
|
}
|
|
|
|
// JSPurpleBuffer keeps references to GCThings which might affect the
|
|
// next cycle collection. It is owned only by itself and during unlink its
|
|
// self reference is broken down and the object ends up killing itself.
|
|
// If GC happens before CC, references to GCthings and the self reference are
|
|
// removed.
|
|
class JSPurpleBuffer
|
|
{
|
|
~JSPurpleBuffer()
|
|
{
|
|
MOZ_ASSERT(mValues.IsEmpty());
|
|
MOZ_ASSERT(mObjects.IsEmpty());
|
|
}
|
|
|
|
public:
|
|
explicit JSPurpleBuffer(RefPtr<JSPurpleBuffer>& aReferenceToThis)
|
|
: mReferenceToThis(aReferenceToThis)
|
|
, mValues(kSegmentSize)
|
|
, mObjects(kSegmentSize)
|
|
{
|
|
mReferenceToThis = this;
|
|
mozilla::HoldJSObjects(this);
|
|
}
|
|
|
|
void Destroy()
|
|
{
|
|
mReferenceToThis = nullptr;
|
|
mValues.Clear();
|
|
mObjects.Clear();
|
|
mozilla::DropJSObjects(this);
|
|
}
|
|
|
|
NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(JSPurpleBuffer)
|
|
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(JSPurpleBuffer)
|
|
|
|
RefPtr<JSPurpleBuffer>& mReferenceToThis;
|
|
|
|
// These are raw pointers instead of Heap<T> because we only need Heap<T> for
|
|
// pointers which may point into the nursery. The purple buffer never contains
|
|
// pointers to the nursery because nursery gcthings can never be gray and only
|
|
// gray things can be inserted into the purple buffer.
|
|
static const size_t kSegmentSize = 512;
|
|
SegmentedVector<JS::Value, kSegmentSize, InfallibleAllocPolicy> mValues;
|
|
SegmentedVector<JSObject*, kSegmentSize, InfallibleAllocPolicy> mObjects;
|
|
};
|
|
|
|
NS_IMPL_CYCLE_COLLECTION_CLASS(JSPurpleBuffer)
|
|
|
|
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(JSPurpleBuffer)
|
|
tmp->Destroy();
|
|
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
|
|
|
|
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(JSPurpleBuffer)
|
|
CycleCollectionNoteChild(cb, tmp, "self");
|
|
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
|
|
|
|
#define NS_TRACE_SEGMENTED_ARRAY(_field, _type) \
|
|
{ \
|
|
for (auto iter = tmp->_field.Iter(); !iter.Done(); iter.Next()) { \
|
|
js::gc::CallTraceCallbackOnNonHeap<_type, TraceCallbacks>( \
|
|
&iter.Get(), aCallbacks, #_field, aClosure); \
|
|
} \
|
|
}
|
|
|
|
NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(JSPurpleBuffer)
|
|
NS_TRACE_SEGMENTED_ARRAY(mValues, JS::Value)
|
|
NS_TRACE_SEGMENTED_ARRAY(mObjects, JSObject*)
|
|
NS_IMPL_CYCLE_COLLECTION_TRACE_END
|
|
|
|
NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(JSPurpleBuffer, AddRef)
|
|
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(JSPurpleBuffer, Release)
|
|
|
|
class SnowWhiteKiller : public TraceCallbacks
|
|
{
|
|
struct SnowWhiteObject
|
|
{
|
|
void* mPointer;
|
|
nsCycleCollectionParticipant* mParticipant;
|
|
nsCycleCollectingAutoRefCnt* mRefCnt;
|
|
};
|
|
|
|
// Segments are 4 KiB on 32-bit and 8 KiB on 64-bit.
|
|
static const size_t kSegmentSize = sizeof(void*) * 1024;
|
|
typedef SegmentedVector<SnowWhiteObject, kSegmentSize, InfallibleAllocPolicy>
|
|
ObjectsVector;
|
|
|
|
public:
|
|
explicit SnowWhiteKiller(nsCycleCollector* aCollector)
|
|
: mCollector(aCollector)
|
|
, mObjects(kSegmentSize)
|
|
{
|
|
MOZ_ASSERT(mCollector, "Calling SnowWhiteKiller after nsCC went away");
|
|
}
|
|
|
|
~SnowWhiteKiller()
|
|
{
|
|
for (auto iter = mObjects.Iter(); !iter.Done(); iter.Next()) {
|
|
SnowWhiteObject& o = iter.Get();
|
|
if (!o.mRefCnt->get() && !o.mRefCnt->IsInPurpleBuffer()) {
|
|
mCollector->RemoveObjectFromGraph(o.mPointer);
|
|
o.mRefCnt->stabilizeForDeletion();
|
|
{
|
|
JS::AutoEnterCycleCollection autocc(mCollector->Context()->Context());
|
|
o.mParticipant->Trace(o.mPointer, *this, nullptr);
|
|
}
|
|
o.mParticipant->DeleteCycleCollectable(o.mPointer);
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
Visit(nsPurpleBuffer& aBuffer, nsPurpleBufferEntry* aEntry)
|
|
{
|
|
MOZ_ASSERT(aEntry->mObject, "Null object in purple buffer");
|
|
if (!aEntry->mRefCnt->get()) {
|
|
void* o = aEntry->mObject;
|
|
nsCycleCollectionParticipant* cp = aEntry->mParticipant;
|
|
CanonicalizeParticipant(&o, &cp);
|
|
SnowWhiteObject swo = { o, cp, aEntry->mRefCnt };
|
|
mObjects.InfallibleAppend(swo);
|
|
aBuffer.Remove(aEntry);
|
|
}
|
|
}
|
|
|
|
bool HasSnowWhiteObjects() const
|
|
{
|
|
return !mObjects.IsEmpty();
|
|
}
|
|
|
|
virtual void Trace(JS::Heap<JS::Value>* aValue, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
const JS::Value& val = aValue->unbarrieredGet();
|
|
if (val.isGCThing() && ValueIsGrayCCThing(val)) {
|
|
MOZ_ASSERT(!js::gc::IsInsideNursery(val.toGCThing()));
|
|
mCollector->GetJSPurpleBuffer()->mValues.InfallibleAppend(val);
|
|
}
|
|
}
|
|
|
|
virtual void Trace(JS::Heap<jsid>* aId, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
}
|
|
|
|
void AppendJSObjectToPurpleBuffer(JSObject* obj) const
|
|
{
|
|
if (obj && JS::ObjectIsMarkedGray(obj)) {
|
|
MOZ_ASSERT(JS::ObjectIsTenured(obj));
|
|
mCollector->GetJSPurpleBuffer()->mObjects.InfallibleAppend(obj);
|
|
}
|
|
}
|
|
|
|
virtual void Trace(JS::Heap<JSObject*>* aObject, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
AppendJSObjectToPurpleBuffer(aObject->unbarrieredGet());
|
|
}
|
|
|
|
virtual void Trace(JSObject** aObject, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
AppendJSObjectToPurpleBuffer(*aObject);
|
|
}
|
|
|
|
virtual void Trace(JS::TenuredHeap<JSObject*>* aObject, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
AppendJSObjectToPurpleBuffer(aObject->unbarrieredGetPtr());
|
|
}
|
|
|
|
virtual void Trace(JS::Heap<JSString*>* aString, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
}
|
|
|
|
virtual void Trace(JS::Heap<JSScript*>* aScript, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
}
|
|
|
|
virtual void Trace(JS::Heap<JSFunction*>* aFunction, const char* aName,
|
|
void* aClosure) const override
|
|
{
|
|
}
|
|
|
|
private:
|
|
RefPtr<nsCycleCollector> mCollector;
|
|
ObjectsVector mObjects;
|
|
};
|
|
|
|
class RemoveSkippableVisitor : public SnowWhiteKiller
|
|
{
|
|
public:
|
|
RemoveSkippableVisitor(nsCycleCollector* aCollector,
|
|
bool aRemoveChildlessNodes,
|
|
bool aAsyncSnowWhiteFreeing,
|
|
CC_ForgetSkippableCallback aCb)
|
|
: SnowWhiteKiller(aCollector)
|
|
, mRemoveChildlessNodes(aRemoveChildlessNodes)
|
|
, mAsyncSnowWhiteFreeing(aAsyncSnowWhiteFreeing)
|
|
, mDispatchedDeferredDeletion(false)
|
|
, mCallback(aCb)
|
|
{
|
|
}
|
|
|
|
~RemoveSkippableVisitor()
|
|
{
|
|
// Note, we must call the callback before SnowWhiteKiller calls
|
|
// DeleteCycleCollectable!
|
|
if (mCallback) {
|
|
mCallback();
|
|
}
|
|
if (HasSnowWhiteObjects()) {
|
|
// Effectively a continuation.
|
|
nsCycleCollector_dispatchDeferredDeletion(true);
|
|
}
|
|
}
|
|
|
|
void
|
|
Visit(nsPurpleBuffer& aBuffer, nsPurpleBufferEntry* aEntry)
|
|
{
|
|
MOZ_ASSERT(aEntry->mObject, "null mObject in purple buffer");
|
|
if (!aEntry->mRefCnt->get()) {
|
|
if (!mAsyncSnowWhiteFreeing) {
|
|
SnowWhiteKiller::Visit(aBuffer, aEntry);
|
|
} else if (!mDispatchedDeferredDeletion) {
|
|
mDispatchedDeferredDeletion = true;
|
|
nsCycleCollector_dispatchDeferredDeletion(false);
|
|
}
|
|
return;
|
|
}
|
|
void* o = aEntry->mObject;
|
|
nsCycleCollectionParticipant* cp = aEntry->mParticipant;
|
|
CanonicalizeParticipant(&o, &cp);
|
|
if (aEntry->mRefCnt->IsPurple() && !cp->CanSkip(o, false) &&
|
|
(!mRemoveChildlessNodes || MayHaveChild(o, cp))) {
|
|
return;
|
|
}
|
|
aBuffer.Remove(aEntry);
|
|
}
|
|
|
|
private:
|
|
bool mRemoveChildlessNodes;
|
|
bool mAsyncSnowWhiteFreeing;
|
|
bool mDispatchedDeferredDeletion;
|
|
CC_ForgetSkippableCallback mCallback;
|
|
};
|
|
|
|
void
|
|
nsPurpleBuffer::RemoveSkippable(nsCycleCollector* aCollector,
|
|
bool aRemoveChildlessNodes,
|
|
bool aAsyncSnowWhiteFreeing,
|
|
CC_ForgetSkippableCallback aCb)
|
|
{
|
|
RemoveSkippableVisitor visitor(aCollector, aRemoveChildlessNodes,
|
|
aAsyncSnowWhiteFreeing, aCb);
|
|
VisitEntries(visitor);
|
|
}
|
|
|
|
bool
|
|
nsCycleCollector::FreeSnowWhite(bool aUntilNoSWInPurpleBuffer)
|
|
{
|
|
CheckThreadSafety();
|
|
|
|
if (mFreeingSnowWhite) {
|
|
return false;
|
|
}
|
|
|
|
AutoRestore<bool> ar(mFreeingSnowWhite);
|
|
mFreeingSnowWhite = true;
|
|
|
|
bool hadSnowWhiteObjects = false;
|
|
do {
|
|
SnowWhiteKiller visitor(this);
|
|
mPurpleBuf.VisitEntries(visitor);
|
|
hadSnowWhiteObjects = hadSnowWhiteObjects ||
|
|
visitor.HasSnowWhiteObjects();
|
|
if (!visitor.HasSnowWhiteObjects()) {
|
|
break;
|
|
}
|
|
} while (aUntilNoSWInPurpleBuffer);
|
|
return hadSnowWhiteObjects;
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::ForgetSkippable(bool aRemoveChildlessNodes,
|
|
bool aAsyncSnowWhiteFreeing)
|
|
{
|
|
CheckThreadSafety();
|
|
|
|
mozilla::Maybe<mozilla::AutoGlobalTimelineMarker> marker;
|
|
if (NS_IsMainThread()) {
|
|
marker.emplace("nsCycleCollector::ForgetSkippable", MarkerStackRequest::NO_STACK);
|
|
}
|
|
|
|
// If we remove things from the purple buffer during graph building, we may
|
|
// lose track of an object that was mutated during graph building.
|
|
MOZ_ASSERT(IsIdle());
|
|
|
|
if (mJSContext) {
|
|
mJSContext->PrepareForForgetSkippable();
|
|
}
|
|
MOZ_ASSERT(!mScanInProgress,
|
|
"Don't forget skippable or free snow-white while scan is in progress.");
|
|
mPurpleBuf.RemoveSkippable(this, aRemoveChildlessNodes,
|
|
aAsyncSnowWhiteFreeing, mForgetSkippableCB);
|
|
}
|
|
|
|
MOZ_NEVER_INLINE void
|
|
nsCycleCollector::MarkRoots(SliceBudget& aBudget)
|
|
{
|
|
JS::AutoAssertNoGC nogc;
|
|
TimeLog timeLog;
|
|
AutoRestore<bool> ar(mScanInProgress);
|
|
MOZ_RELEASE_ASSERT(!mScanInProgress);
|
|
mScanInProgress = true;
|
|
MOZ_ASSERT(mIncrementalPhase == GraphBuildingPhase);
|
|
|
|
JS::AutoEnterCycleCollection autocc(Context()->Context());
|
|
bool doneBuilding = mBuilder->BuildGraph(aBudget);
|
|
|
|
if (!doneBuilding) {
|
|
timeLog.Checkpoint("MarkRoots()");
|
|
return;
|
|
}
|
|
|
|
mBuilder = nullptr;
|
|
mIncrementalPhase = ScanAndCollectWhitePhase;
|
|
timeLog.Checkpoint("MarkRoots()");
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// Bacon & Rajan's |ScanRoots| routine.
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
|
|
struct ScanBlackVisitor
|
|
{
|
|
ScanBlackVisitor(uint32_t& aWhiteNodeCount, bool& aFailed)
|
|
: mWhiteNodeCount(aWhiteNodeCount), mFailed(aFailed)
|
|
{
|
|
}
|
|
|
|
bool ShouldVisitNode(PtrInfo const* aPi)
|
|
{
|
|
return aPi->mColor != black;
|
|
}
|
|
|
|
MOZ_NEVER_INLINE void VisitNode(PtrInfo* aPi)
|
|
{
|
|
if (aPi->mColor == white) {
|
|
--mWhiteNodeCount;
|
|
}
|
|
aPi->mColor = black;
|
|
}
|
|
|
|
void Failed()
|
|
{
|
|
mFailed = true;
|
|
}
|
|
|
|
private:
|
|
uint32_t& mWhiteNodeCount;
|
|
bool& mFailed;
|
|
};
|
|
|
|
static void
|
|
FloodBlackNode(uint32_t& aWhiteNodeCount, bool& aFailed, PtrInfo* aPi)
|
|
{
|
|
GraphWalker<ScanBlackVisitor>(ScanBlackVisitor(aWhiteNodeCount,
|
|
aFailed)).Walk(aPi);
|
|
MOZ_ASSERT(aPi->mColor == black || !aPi->WasTraversed(),
|
|
"FloodBlackNode should make aPi black");
|
|
}
|
|
|
|
// Iterate over the WeakMaps. If we mark anything while iterating
|
|
// over the WeakMaps, we must iterate over all of the WeakMaps again.
|
|
void
|
|
nsCycleCollector::ScanWeakMaps()
|
|
{
|
|
bool anyChanged;
|
|
bool failed = false;
|
|
do {
|
|
anyChanged = false;
|
|
for (uint32_t i = 0; i < mGraph.mWeakMaps.Length(); i++) {
|
|
WeakMapping* wm = &mGraph.mWeakMaps[i];
|
|
|
|
// If any of these are null, the original object was marked black.
|
|
uint32_t mColor = wm->mMap ? wm->mMap->mColor : black;
|
|
uint32_t kColor = wm->mKey ? wm->mKey->mColor : black;
|
|
uint32_t kdColor = wm->mKeyDelegate ? wm->mKeyDelegate->mColor : black;
|
|
uint32_t vColor = wm->mVal ? wm->mVal->mColor : black;
|
|
|
|
MOZ_ASSERT(mColor != grey, "Uncolored weak map");
|
|
MOZ_ASSERT(kColor != grey, "Uncolored weak map key");
|
|
MOZ_ASSERT(kdColor != grey, "Uncolored weak map key delegate");
|
|
MOZ_ASSERT(vColor != grey, "Uncolored weak map value");
|
|
|
|
if (mColor == black && kColor != black && kdColor == black) {
|
|
FloodBlackNode(mWhiteNodeCount, failed, wm->mKey);
|
|
anyChanged = true;
|
|
}
|
|
|
|
if (mColor == black && kColor == black && vColor != black) {
|
|
FloodBlackNode(mWhiteNodeCount, failed, wm->mVal);
|
|
anyChanged = true;
|
|
}
|
|
}
|
|
} while (anyChanged);
|
|
|
|
if (failed) {
|
|
MOZ_ASSERT(false, "Ran out of memory in ScanWeakMaps");
|
|
CC_TELEMETRY(_OOM, true);
|
|
}
|
|
}
|
|
|
|
// Flood black from any objects in the purple buffer that are in the CC graph.
|
|
class PurpleScanBlackVisitor
|
|
{
|
|
public:
|
|
PurpleScanBlackVisitor(CCGraph& aGraph, nsCycleCollectorLogger* aLogger,
|
|
uint32_t& aCount, bool& aFailed)
|
|
: mGraph(aGraph), mLogger(aLogger), mCount(aCount), mFailed(aFailed)
|
|
{
|
|
}
|
|
|
|
void
|
|
Visit(nsPurpleBuffer& aBuffer, nsPurpleBufferEntry* aEntry)
|
|
{
|
|
MOZ_ASSERT(aEntry->mObject,
|
|
"Entries with null mObject shouldn't be in the purple buffer.");
|
|
MOZ_ASSERT(aEntry->mRefCnt->get() != 0,
|
|
"Snow-white objects shouldn't be in the purple buffer.");
|
|
|
|
void* obj = aEntry->mObject;
|
|
if (!aEntry->mParticipant) {
|
|
obj = CanonicalizeXPCOMParticipant(static_cast<nsISupports*>(obj));
|
|
MOZ_ASSERT(obj, "Don't add objects that don't participate in collection!");
|
|
}
|
|
|
|
PtrInfo* pi = mGraph.FindNode(obj);
|
|
if (!pi) {
|
|
return;
|
|
}
|
|
MOZ_ASSERT(pi->mParticipant, "No dead objects should be in the purple buffer.");
|
|
if (MOZ_UNLIKELY(mLogger)) {
|
|
mLogger->NoteIncrementalRoot((uint64_t)pi->mPointer);
|
|
}
|
|
if (pi->mColor == black) {
|
|
return;
|
|
}
|
|
FloodBlackNode(mCount, mFailed, pi);
|
|
}
|
|
|
|
private:
|
|
CCGraph& mGraph;
|
|
RefPtr<nsCycleCollectorLogger> mLogger;
|
|
uint32_t& mCount;
|
|
bool& mFailed;
|
|
};
|
|
|
|
// Objects that have been stored somewhere since the start of incremental graph building must
|
|
// be treated as live for this cycle collection, because we may not have accurate information
|
|
// about who holds references to them.
|
|
void
|
|
nsCycleCollector::ScanIncrementalRoots()
|
|
{
|
|
TimeLog timeLog;
|
|
|
|
// Reference counted objects:
|
|
// We cleared the purple buffer at the start of the current ICC, so if a
|
|
// refcounted object is purple, it may have been AddRef'd during the current
|
|
// ICC. (It may also have only been released.) If that is the case, we cannot
|
|
// be sure that the set of things pointing to the object in the CC graph
|
|
// is accurate. Therefore, for safety, we treat any purple objects as being
|
|
// live during the current CC. We don't remove anything from the purple
|
|
// buffer here, so these objects will be suspected and freed in the next CC
|
|
// if they are garbage.
|
|
bool failed = false;
|
|
PurpleScanBlackVisitor purpleScanBlackVisitor(mGraph, mLogger,
|
|
mWhiteNodeCount, failed);
|
|
mPurpleBuf.VisitEntries(purpleScanBlackVisitor);
|
|
timeLog.Checkpoint("ScanIncrementalRoots::fix purple");
|
|
|
|
bool hasJSContext = !!mJSContext;
|
|
nsCycleCollectionParticipant* jsParticipant =
|
|
hasJSContext ? mJSContext->GCThingParticipant() : nullptr;
|
|
nsCycleCollectionParticipant* zoneParticipant =
|
|
hasJSContext ? mJSContext->ZoneParticipant() : nullptr;
|
|
bool hasLogger = !!mLogger;
|
|
|
|
NodePool::Enumerator etor(mGraph.mNodes);
|
|
while (!etor.IsDone()) {
|
|
PtrInfo* pi = etor.GetNext();
|
|
|
|
// As an optimization, if an object has already been determined to be live,
|
|
// don't consider it further. We can't do this if there is a listener,
|
|
// because the listener wants to know the complete set of incremental roots.
|
|
if (pi->mColor == black && MOZ_LIKELY(!hasLogger)) {
|
|
continue;
|
|
}
|
|
|
|
// Garbage collected objects:
|
|
// If a GCed object was added to the graph with a refcount of zero, and is
|
|
// now marked black by the GC, it was probably gray before and was exposed
|
|
// to active JS, so it may have been stored somewhere, so it needs to be
|
|
// treated as live.
|
|
if (pi->IsGrayJS() && MOZ_LIKELY(hasJSContext)) {
|
|
// If the object is still marked gray by the GC, nothing could have gotten
|
|
// hold of it, so it isn't an incremental root.
|
|
if (pi->mParticipant == jsParticipant) {
|
|
JS::GCCellPtr ptr(pi->mPointer, JS::GCThingTraceKind(pi->mPointer));
|
|
if (GCThingIsGrayCCThing(ptr)) {
|
|
continue;
|
|
}
|
|
} else if (pi->mParticipant == zoneParticipant) {
|
|
JS::Zone* zone = static_cast<JS::Zone*>(pi->mPointer);
|
|
if (js::ZoneGlobalsAreAllGray(zone)) {
|
|
continue;
|
|
}
|
|
} else {
|
|
MOZ_ASSERT(false, "Non-JS thing with 0 refcount? Treating as live.");
|
|
}
|
|
} else if (!pi->mParticipant && pi->WasTraversed()) {
|
|
// Dead traversed refcounted objects:
|
|
// If the object was traversed, it must have been alive at the start of
|
|
// the CC, and thus had a positive refcount. It is dead now, so its
|
|
// refcount must have decreased at some point during the CC. Therefore,
|
|
// it would be in the purple buffer if it wasn't dead, so treat it as an
|
|
// incremental root.
|
|
//
|
|
// This should not cause leaks because as the object died it should have
|
|
// released anything it held onto, which will add them to the purple
|
|
// buffer, which will cause them to be considered in the next CC.
|
|
} else {
|
|
continue;
|
|
}
|
|
|
|
// At this point, pi must be an incremental root.
|
|
|
|
// If there's a listener, tell it about this root. We don't bother with the
|
|
// optimization of skipping the Walk() if pi is black: it will just return
|
|
// without doing anything and there's no need to make this case faster.
|
|
if (MOZ_UNLIKELY(hasLogger) && pi->mPointer) {
|
|
// Dead objects aren't logged. See bug 1031370.
|
|
mLogger->NoteIncrementalRoot((uint64_t)pi->mPointer);
|
|
}
|
|
|
|
FloodBlackNode(mWhiteNodeCount, failed, pi);
|
|
}
|
|
|
|
timeLog.Checkpoint("ScanIncrementalRoots::fix nodes");
|
|
|
|
if (failed) {
|
|
NS_ASSERTION(false, "Ran out of memory in ScanIncrementalRoots");
|
|
CC_TELEMETRY(_OOM, true);
|
|
}
|
|
}
|
|
|
|
// Mark nodes white and make sure their refcounts are ok.
|
|
// No nodes are marked black during this pass to ensure that refcount
|
|
// checking is run on all nodes not marked black by ScanIncrementalRoots.
|
|
void
|
|
nsCycleCollector::ScanWhiteNodes(bool aFullySynchGraphBuild)
|
|
{
|
|
NodePool::Enumerator nodeEnum(mGraph.mNodes);
|
|
while (!nodeEnum.IsDone()) {
|
|
PtrInfo* pi = nodeEnum.GetNext();
|
|
if (pi->mColor == black) {
|
|
// Incremental roots can be in a nonsensical state, so don't
|
|
// check them. This will miss checking nodes that are merely
|
|
// reachable from incremental roots.
|
|
MOZ_ASSERT(!aFullySynchGraphBuild,
|
|
"In a synch CC, no nodes should be marked black early on.");
|
|
continue;
|
|
}
|
|
MOZ_ASSERT(pi->mColor == grey);
|
|
|
|
if (!pi->WasTraversed()) {
|
|
// This node was deleted before it was traversed, so there's no reason
|
|
// to look at it.
|
|
MOZ_ASSERT(!pi->mParticipant, "Live nodes should all have been traversed");
|
|
continue;
|
|
}
|
|
|
|
if (pi->mInternalRefs == pi->mRefCount || pi->IsGrayJS()) {
|
|
pi->mColor = white;
|
|
++mWhiteNodeCount;
|
|
continue;
|
|
}
|
|
|
|
if (pi->mInternalRefs > pi->mRefCount) {
|
|
#ifdef MOZ_CRASHREPORTER
|
|
const char* piName = "Unknown";
|
|
if (pi->mParticipant) {
|
|
piName = pi->mParticipant->ClassName();
|
|
}
|
|
nsPrintfCString msg("More references to an object than its refcount, for class %s", piName);
|
|
CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("CycleCollector"), msg);
|
|
#endif
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
// This node will get marked black in the next pass.
|
|
}
|
|
}
|
|
|
|
// Any remaining grey nodes that haven't already been deleted must be alive,
|
|
// so mark them and their children black. Any nodes that are black must have
|
|
// already had their children marked black, so there's no need to look at them
|
|
// again. This pass may turn some white nodes to black.
|
|
void
|
|
nsCycleCollector::ScanBlackNodes()
|
|
{
|
|
bool failed = false;
|
|
NodePool::Enumerator nodeEnum(mGraph.mNodes);
|
|
while (!nodeEnum.IsDone()) {
|
|
PtrInfo* pi = nodeEnum.GetNext();
|
|
if (pi->mColor == grey && pi->WasTraversed()) {
|
|
FloodBlackNode(mWhiteNodeCount, failed, pi);
|
|
}
|
|
}
|
|
|
|
if (failed) {
|
|
NS_ASSERTION(false, "Ran out of memory in ScanBlackNodes");
|
|
CC_TELEMETRY(_OOM, true);
|
|
}
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::ScanRoots(bool aFullySynchGraphBuild)
|
|
{
|
|
JS::AutoAssertNoGC nogc;
|
|
AutoRestore<bool> ar(mScanInProgress);
|
|
MOZ_RELEASE_ASSERT(!mScanInProgress);
|
|
mScanInProgress = true;
|
|
mWhiteNodeCount = 0;
|
|
MOZ_ASSERT(mIncrementalPhase == ScanAndCollectWhitePhase);
|
|
|
|
JS::AutoEnterCycleCollection autocc(Context()->Context());
|
|
|
|
if (!aFullySynchGraphBuild) {
|
|
ScanIncrementalRoots();
|
|
}
|
|
|
|
TimeLog timeLog;
|
|
ScanWhiteNodes(aFullySynchGraphBuild);
|
|
timeLog.Checkpoint("ScanRoots::ScanWhiteNodes");
|
|
|
|
ScanBlackNodes();
|
|
timeLog.Checkpoint("ScanRoots::ScanBlackNodes");
|
|
|
|
// Scanning weak maps must be done last.
|
|
ScanWeakMaps();
|
|
timeLog.Checkpoint("ScanRoots::ScanWeakMaps");
|
|
|
|
if (mLogger) {
|
|
mLogger->BeginResults();
|
|
|
|
NodePool::Enumerator etor(mGraph.mNodes);
|
|
while (!etor.IsDone()) {
|
|
PtrInfo* pi = etor.GetNext();
|
|
if (!pi->WasTraversed()) {
|
|
continue;
|
|
}
|
|
switch (pi->mColor) {
|
|
case black:
|
|
if (!pi->IsGrayJS() && !pi->IsBlackJS() &&
|
|
pi->mInternalRefs != pi->mRefCount) {
|
|
mLogger->DescribeRoot((uint64_t)pi->mPointer,
|
|
pi->mInternalRefs);
|
|
}
|
|
break;
|
|
case white:
|
|
mLogger->DescribeGarbage((uint64_t)pi->mPointer);
|
|
break;
|
|
case grey:
|
|
MOZ_ASSERT(false, "All traversed objects should be black or white");
|
|
break;
|
|
}
|
|
}
|
|
|
|
mLogger->End();
|
|
mLogger = nullptr;
|
|
timeLog.Checkpoint("ScanRoots::listener");
|
|
}
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// Bacon & Rajan's |CollectWhite| routine, somewhat modified.
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
bool
|
|
nsCycleCollector::CollectWhite()
|
|
{
|
|
// Explanation of "somewhat modified": we have no way to collect the
|
|
// set of whites "all at once", we have to ask each of them to drop
|
|
// their outgoing links and assume this will cause the garbage cycle
|
|
// to *mostly* self-destruct (except for the reference we continue
|
|
// to hold).
|
|
//
|
|
// To do this "safely" we must make sure that the white nodes we're
|
|
// operating on are stable for the duration of our operation. So we
|
|
// make 3 sets of calls to language runtimes:
|
|
//
|
|
// - Root(whites), which should pin the whites in memory.
|
|
// - Unlink(whites), which drops outgoing links on each white.
|
|
// - Unroot(whites), which returns the whites to normal GC.
|
|
|
|
// Segments are 4 KiB on 32-bit and 8 KiB on 64-bit.
|
|
static const size_t kSegmentSize = sizeof(void*) * 1024;
|
|
SegmentedVector<PtrInfo*, kSegmentSize, InfallibleAllocPolicy>
|
|
whiteNodes(kSegmentSize);
|
|
TimeLog timeLog;
|
|
|
|
MOZ_ASSERT(mIncrementalPhase == ScanAndCollectWhitePhase);
|
|
|
|
uint32_t numWhiteNodes = 0;
|
|
uint32_t numWhiteGCed = 0;
|
|
uint32_t numWhiteJSZones = 0;
|
|
|
|
{
|
|
JS::AutoAssertNoGC nogc;
|
|
bool hasJSContext = !!mJSContext;
|
|
nsCycleCollectionParticipant* zoneParticipant =
|
|
hasJSContext ? mJSContext->ZoneParticipant() : nullptr;
|
|
|
|
NodePool::Enumerator etor(mGraph.mNodes);
|
|
while (!etor.IsDone()) {
|
|
PtrInfo* pinfo = etor.GetNext();
|
|
if (pinfo->mColor == white && pinfo->mParticipant) {
|
|
if (pinfo->IsGrayJS()) {
|
|
MOZ_ASSERT(mJSContext);
|
|
++numWhiteGCed;
|
|
JS::Zone* zone;
|
|
if (MOZ_UNLIKELY(pinfo->mParticipant == zoneParticipant)) {
|
|
++numWhiteJSZones;
|
|
zone = static_cast<JS::Zone*>(pinfo->mPointer);
|
|
} else {
|
|
JS::GCCellPtr ptr(pinfo->mPointer, JS::GCThingTraceKind(pinfo->mPointer));
|
|
zone = JS::GetTenuredGCThingZone(ptr);
|
|
}
|
|
mJSContext->AddZoneWaitingForGC(zone);
|
|
} else {
|
|
whiteNodes.InfallibleAppend(pinfo);
|
|
pinfo->mParticipant->Root(pinfo->mPointer);
|
|
++numWhiteNodes;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
mResults.mFreedRefCounted += numWhiteNodes;
|
|
mResults.mFreedGCed += numWhiteGCed;
|
|
mResults.mFreedJSZones += numWhiteJSZones;
|
|
|
|
timeLog.Checkpoint("CollectWhite::Root");
|
|
|
|
if (mBeforeUnlinkCB) {
|
|
mBeforeUnlinkCB();
|
|
timeLog.Checkpoint("CollectWhite::BeforeUnlinkCB");
|
|
}
|
|
|
|
// Unlink() can trigger a GC, so do not touch any JS or anything
|
|
// else not in whiteNodes after here.
|
|
|
|
for (auto iter = whiteNodes.Iter(); !iter.Done(); iter.Next()) {
|
|
PtrInfo* pinfo = iter.Get();
|
|
MOZ_ASSERT(pinfo->mParticipant,
|
|
"Unlink shouldn't see objects removed from graph.");
|
|
pinfo->mParticipant->Unlink(pinfo->mPointer);
|
|
#ifdef DEBUG
|
|
if (mJSContext) {
|
|
mJSContext->AssertNoObjectsToTrace(pinfo->mPointer);
|
|
}
|
|
#endif
|
|
}
|
|
timeLog.Checkpoint("CollectWhite::Unlink");
|
|
|
|
JS::AutoAssertNoGC nogc;
|
|
for (auto iter = whiteNodes.Iter(); !iter.Done(); iter.Next()) {
|
|
PtrInfo* pinfo = iter.Get();
|
|
MOZ_ASSERT(pinfo->mParticipant,
|
|
"Unroot shouldn't see objects removed from graph.");
|
|
pinfo->mParticipant->Unroot(pinfo->mPointer);
|
|
}
|
|
timeLog.Checkpoint("CollectWhite::Unroot");
|
|
|
|
nsCycleCollector_dispatchDeferredDeletion(false, true);
|
|
timeLog.Checkpoint("CollectWhite::dispatchDeferredDeletion");
|
|
|
|
mIncrementalPhase = CleanupPhase;
|
|
|
|
return numWhiteNodes > 0 || numWhiteGCed > 0 || numWhiteJSZones > 0;
|
|
}
|
|
|
|
|
|
////////////////////////
|
|
// Memory reporting
|
|
////////////////////////
|
|
|
|
MOZ_DEFINE_MALLOC_SIZE_OF(CycleCollectorMallocSizeOf)
|
|
|
|
NS_IMETHODIMP
|
|
nsCycleCollector::CollectReports(nsIHandleReportCallback* aHandleReport,
|
|
nsISupports* aData, bool aAnonymize)
|
|
{
|
|
size_t objectSize, graphSize, purpleBufferSize;
|
|
SizeOfIncludingThis(CycleCollectorMallocSizeOf,
|
|
&objectSize, &graphSize,
|
|
&purpleBufferSize);
|
|
|
|
if (objectSize > 0) {
|
|
MOZ_COLLECT_REPORT(
|
|
"explicit/cycle-collector/collector-object", KIND_HEAP, UNITS_BYTES,
|
|
objectSize,
|
|
"Memory used for the cycle collector object itself.");
|
|
}
|
|
|
|
if (graphSize > 0) {
|
|
MOZ_COLLECT_REPORT(
|
|
"explicit/cycle-collector/graph", KIND_HEAP, UNITS_BYTES,
|
|
graphSize,
|
|
"Memory used for the cycle collector's graph. This should be zero when "
|
|
"the collector is idle.");
|
|
}
|
|
|
|
if (purpleBufferSize > 0) {
|
|
MOZ_COLLECT_REPORT(
|
|
"explicit/cycle-collector/purple-buffer", KIND_HEAP, UNITS_BYTES,
|
|
purpleBufferSize,
|
|
"Memory used for the cycle collector's purple buffer.");
|
|
}
|
|
|
|
return NS_OK;
|
|
};
|
|
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// Collector implementation
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
nsCycleCollector::nsCycleCollector() :
|
|
mActivelyCollecting(false),
|
|
mFreeingSnowWhite(false),
|
|
mScanInProgress(false),
|
|
mJSContext(nullptr),
|
|
mIncrementalPhase(IdlePhase),
|
|
#ifdef DEBUG
|
|
mThread(NS_GetCurrentThread()),
|
|
#endif
|
|
mWhiteNodeCount(0),
|
|
mBeforeUnlinkCB(nullptr),
|
|
mForgetSkippableCB(nullptr),
|
|
mUnmergedNeeded(0),
|
|
mMergedInARow(0)
|
|
{
|
|
}
|
|
|
|
nsCycleCollector::~nsCycleCollector()
|
|
{
|
|
UnregisterWeakMemoryReporter(this);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::RegisterJSContext(CycleCollectedJSContext* aJSContext)
|
|
{
|
|
MOZ_RELEASE_ASSERT(!mJSContext, "Multiple registrations of JS context in cycle collector");
|
|
mJSContext = aJSContext;
|
|
|
|
if (!NS_IsMainThread()) {
|
|
return;
|
|
}
|
|
|
|
// We can't register as a reporter in nsCycleCollector() because that runs
|
|
// before the memory reporter manager is initialized. So we do it here
|
|
// instead.
|
|
RegisterWeakMemoryReporter(this);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::ForgetJSContext()
|
|
{
|
|
MOZ_RELEASE_ASSERT(mJSContext, "Forgetting JS context in cycle collector before a JS context was registered");
|
|
mJSContext = nullptr;
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
static bool
|
|
HasParticipant(void* aPtr, nsCycleCollectionParticipant* aParti)
|
|
{
|
|
if (aParti) {
|
|
return true;
|
|
}
|
|
|
|
nsXPCOMCycleCollectionParticipant* xcp;
|
|
ToParticipant(static_cast<nsISupports*>(aPtr), &xcp);
|
|
return xcp != nullptr;
|
|
}
|
|
#endif
|
|
|
|
MOZ_ALWAYS_INLINE void
|
|
nsCycleCollector::Suspect(void* aPtr, nsCycleCollectionParticipant* aParti,
|
|
nsCycleCollectingAutoRefCnt* aRefCnt)
|
|
{
|
|
CheckThreadSafety();
|
|
|
|
// Don't call AddRef or Release of a CCed object in a Traverse() method.
|
|
MOZ_ASSERT(!mScanInProgress, "Attempted to call Suspect() while a scan was in progress");
|
|
|
|
if (MOZ_UNLIKELY(mScanInProgress)) {
|
|
return;
|
|
}
|
|
|
|
MOZ_ASSERT(aPtr, "Don't suspect null pointers");
|
|
|
|
MOZ_ASSERT(HasParticipant(aPtr, aParti),
|
|
"Suspected nsISupports pointer must QI to nsXPCOMCycleCollectionParticipant");
|
|
|
|
mPurpleBuf.Put(aPtr, aParti, aRefCnt);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::CheckThreadSafety()
|
|
{
|
|
#ifdef DEBUG
|
|
nsIThread* currentThread = NS_GetCurrentThread();
|
|
// XXXkhuey we can be called so late in shutdown that NS_GetCurrentThread
|
|
// returns null (after the thread manager has shut down)
|
|
MOZ_ASSERT(mThread == currentThread || !currentThread);
|
|
#endif
|
|
}
|
|
|
|
// The cycle collector uses the mark bitmap to discover what JS objects
|
|
// were reachable only from XPConnect roots that might participate in
|
|
// cycles. We ask the JS context whether we need to force a GC before
|
|
// this CC. It returns true on startup (before the mark bits have been set),
|
|
// and also when UnmarkGray has run out of stack. We also force GCs on shut
|
|
// down to collect cycles involving both DOM and JS.
|
|
void
|
|
nsCycleCollector::FixGrayBits(bool aForceGC, TimeLog& aTimeLog)
|
|
{
|
|
CheckThreadSafety();
|
|
|
|
if (!mJSContext) {
|
|
return;
|
|
}
|
|
|
|
if (!aForceGC) {
|
|
mJSContext->FixWeakMappingGrayBits();
|
|
aTimeLog.Checkpoint("FixWeakMappingGrayBits");
|
|
|
|
bool needGC = !mJSContext->AreGCGrayBitsValid();
|
|
// Only do a telemetry ping for non-shutdown CCs.
|
|
CC_TELEMETRY(_NEED_GC, needGC);
|
|
if (!needGC) {
|
|
return;
|
|
}
|
|
mResults.mForcedGC = true;
|
|
}
|
|
|
|
uint32_t count = 0;
|
|
do {
|
|
mJSContext->GarbageCollect(aForceGC ? JS::gcreason::SHUTDOWN_CC :
|
|
JS::gcreason::CC_FORCED);
|
|
|
|
mJSContext->FixWeakMappingGrayBits();
|
|
|
|
// It's possible that FixWeakMappingGrayBits will hit OOM when unmarking
|
|
// gray and we will have to go round again. The second time there should not
|
|
// be any weak mappings to fix up so the loop body should run at most twice.
|
|
MOZ_RELEASE_ASSERT(count++ < 2);
|
|
} while (!mJSContext->AreGCGrayBitsValid());
|
|
|
|
aTimeLog.Checkpoint("FixGrayBits");
|
|
}
|
|
|
|
bool
|
|
nsCycleCollector::IsIncrementalGCInProgress()
|
|
{
|
|
return mJSContext && JS::IsIncrementalGCInProgress(mJSContext->Context());
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::FinishAnyIncrementalGCInProgress()
|
|
{
|
|
if (IsIncrementalGCInProgress()) {
|
|
NS_WARNING("Finishing incremental GC in progress during CC");
|
|
JS::PrepareForIncrementalGC(mJSContext->Context());
|
|
JS::FinishIncrementalGC(mJSContext->Context(), JS::gcreason::CC_FORCED);
|
|
}
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::CleanupAfterCollection()
|
|
{
|
|
TimeLog timeLog;
|
|
MOZ_ASSERT(mIncrementalPhase == CleanupPhase);
|
|
mGraph.Clear();
|
|
timeLog.Checkpoint("CleanupAfterCollection::mGraph.Clear()");
|
|
|
|
uint32_t interval =
|
|
(uint32_t)((TimeStamp::Now() - mCollectionStart).ToMilliseconds());
|
|
#ifdef COLLECT_TIME_DEBUG
|
|
printf("cc: total cycle collector time was %ums in %u slices\n", interval,
|
|
mResults.mNumSlices);
|
|
printf("cc: visited %u ref counted and %u GCed objects, freed %d ref counted and %d GCed objects",
|
|
mResults.mVisitedRefCounted, mResults.mVisitedGCed,
|
|
mResults.mFreedRefCounted, mResults.mFreedGCed);
|
|
uint32_t numVisited = mResults.mVisitedRefCounted + mResults.mVisitedGCed;
|
|
if (numVisited > 1000) {
|
|
uint32_t numFreed = mResults.mFreedRefCounted + mResults.mFreedGCed;
|
|
printf(" (%d%%)", 100 * numFreed / numVisited);
|
|
}
|
|
printf(".\ncc: \n");
|
|
#endif
|
|
|
|
CC_TELEMETRY( , interval);
|
|
CC_TELEMETRY(_VISITED_REF_COUNTED, mResults.mVisitedRefCounted);
|
|
CC_TELEMETRY(_VISITED_GCED, mResults.mVisitedGCed);
|
|
CC_TELEMETRY(_COLLECTED, mWhiteNodeCount);
|
|
timeLog.Checkpoint("CleanupAfterCollection::telemetry");
|
|
|
|
if (mJSContext) {
|
|
mJSContext->FinalizeDeferredThings(mResults.mAnyManual
|
|
? CycleCollectedJSContext::FinalizeNow
|
|
: CycleCollectedJSContext::FinalizeIncrementally);
|
|
mJSContext->EndCycleCollectionCallback(mResults);
|
|
timeLog.Checkpoint("CleanupAfterCollection::EndCycleCollectionCallback()");
|
|
}
|
|
mIncrementalPhase = IdlePhase;
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::ShutdownCollect()
|
|
{
|
|
FinishAnyIncrementalGCInProgress();
|
|
|
|
SliceBudget unlimitedBudget = SliceBudget::unlimited();
|
|
uint32_t i;
|
|
for (i = 0; i < DEFAULT_SHUTDOWN_COLLECTIONS; ++i) {
|
|
if (!Collect(ShutdownCC, unlimitedBudget, nullptr)) {
|
|
break;
|
|
}
|
|
}
|
|
NS_WARNING_ASSERTION(i < NORMAL_SHUTDOWN_COLLECTIONS, "Extra shutdown CC");
|
|
}
|
|
|
|
static void
|
|
PrintPhase(const char* aPhase)
|
|
{
|
|
#ifdef DEBUG_PHASES
|
|
printf("cc: begin %s on %s\n", aPhase,
|
|
NS_IsMainThread() ? "mainthread" : "worker");
|
|
#endif
|
|
}
|
|
|
|
bool
|
|
nsCycleCollector::Collect(ccType aCCType,
|
|
SliceBudget& aBudget,
|
|
nsICycleCollectorListener* aManualListener,
|
|
bool aPreferShorterSlices)
|
|
{
|
|
CheckThreadSafety();
|
|
|
|
// This can legitimately happen in a few cases. See bug 383651.
|
|
if (mActivelyCollecting || mFreeingSnowWhite) {
|
|
return false;
|
|
}
|
|
mActivelyCollecting = true;
|
|
|
|
MOZ_ASSERT(!IsIncrementalGCInProgress());
|
|
|
|
mozilla::Maybe<mozilla::AutoGlobalTimelineMarker> marker;
|
|
if (NS_IsMainThread()) {
|
|
marker.emplace("nsCycleCollector::Collect", MarkerStackRequest::NO_STACK);
|
|
}
|
|
|
|
bool startedIdle = IsIdle();
|
|
bool collectedAny = false;
|
|
|
|
// If the CC started idle, it will call BeginCollection, which
|
|
// will do FreeSnowWhite, so it doesn't need to be done here.
|
|
if (!startedIdle) {
|
|
TimeLog timeLog;
|
|
FreeSnowWhite(true);
|
|
timeLog.Checkpoint("Collect::FreeSnowWhite");
|
|
}
|
|
|
|
if (aCCType != SliceCC) {
|
|
mResults.mAnyManual = true;
|
|
}
|
|
|
|
++mResults.mNumSlices;
|
|
|
|
bool continueSlice = aBudget.isUnlimited() || !aPreferShorterSlices;
|
|
do {
|
|
switch (mIncrementalPhase) {
|
|
case IdlePhase:
|
|
PrintPhase("BeginCollection");
|
|
BeginCollection(aCCType, aManualListener);
|
|
break;
|
|
case GraphBuildingPhase:
|
|
PrintPhase("MarkRoots");
|
|
MarkRoots(aBudget);
|
|
|
|
// Only continue this slice if we're running synchronously or the
|
|
// next phase will probably be short, to reduce the max pause for this
|
|
// collection.
|
|
// (There's no need to check if we've finished graph building, because
|
|
// if we haven't, we've already exceeded our budget, and will finish
|
|
// this slice anyways.)
|
|
continueSlice = aBudget.isUnlimited() ||
|
|
(mResults.mNumSlices < 3 && !aPreferShorterSlices);
|
|
break;
|
|
case ScanAndCollectWhitePhase:
|
|
// We do ScanRoots and CollectWhite in a single slice to ensure
|
|
// that we won't unlink a live object if a weak reference is
|
|
// promoted to a strong reference after ScanRoots has finished.
|
|
// See bug 926533.
|
|
PrintPhase("ScanRoots");
|
|
ScanRoots(startedIdle);
|
|
PrintPhase("CollectWhite");
|
|
collectedAny = CollectWhite();
|
|
break;
|
|
case CleanupPhase:
|
|
PrintPhase("CleanupAfterCollection");
|
|
CleanupAfterCollection();
|
|
continueSlice = false;
|
|
break;
|
|
}
|
|
if (continueSlice) {
|
|
// Force SliceBudget::isOverBudget to check the time.
|
|
aBudget.step(SliceBudget::CounterReset);
|
|
continueSlice = !aBudget.isOverBudget();
|
|
}
|
|
} while (continueSlice);
|
|
|
|
// Clear mActivelyCollecting here to ensure that a recursive call to
|
|
// Collect() does something.
|
|
mActivelyCollecting = false;
|
|
|
|
if (aCCType != SliceCC && !startedIdle) {
|
|
// We were in the middle of an incremental CC (using its own listener).
|
|
// Somebody has forced a CC, so after having finished out the current CC,
|
|
// run the CC again using the new listener.
|
|
MOZ_ASSERT(IsIdle());
|
|
if (Collect(aCCType, aBudget, aManualListener)) {
|
|
collectedAny = true;
|
|
}
|
|
}
|
|
|
|
MOZ_ASSERT_IF(aCCType != SliceCC, IsIdle());
|
|
|
|
return collectedAny;
|
|
}
|
|
|
|
// Any JS objects we have in the graph could die when we GC, but we
|
|
// don't want to abandon the current CC, because the graph contains
|
|
// information about purple roots. So we synchronously finish off
|
|
// the current CC.
|
|
void
|
|
nsCycleCollector::PrepareForGarbageCollection()
|
|
{
|
|
if (IsIdle()) {
|
|
MOZ_ASSERT(mGraph.IsEmpty(), "Non-empty graph when idle");
|
|
MOZ_ASSERT(!mBuilder, "Non-null builder when idle");
|
|
if (mJSPurpleBuffer) {
|
|
mJSPurpleBuffer->Destroy();
|
|
}
|
|
return;
|
|
}
|
|
|
|
FinishAnyCurrentCollection();
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::FinishAnyCurrentCollection()
|
|
{
|
|
if (IsIdle()) {
|
|
return;
|
|
}
|
|
|
|
SliceBudget unlimitedBudget = SliceBudget::unlimited();
|
|
PrintPhase("FinishAnyCurrentCollection");
|
|
// Use SliceCC because we only want to finish the CC in progress.
|
|
Collect(SliceCC, unlimitedBudget, nullptr);
|
|
|
|
// It is only okay for Collect() to have failed to finish the
|
|
// current CC if we're reentering the CC at some point past
|
|
// graph building. We need to be past the point where the CC will
|
|
// look at JS objects so that it is safe to GC.
|
|
MOZ_ASSERT(IsIdle() ||
|
|
(mActivelyCollecting && mIncrementalPhase != GraphBuildingPhase),
|
|
"Reentered CC during graph building");
|
|
}
|
|
|
|
// Don't merge too many times in a row, and do at least a minimum
|
|
// number of unmerged CCs in a row.
|
|
static const uint32_t kMinConsecutiveUnmerged = 3;
|
|
static const uint32_t kMaxConsecutiveMerged = 3;
|
|
|
|
bool
|
|
nsCycleCollector::ShouldMergeZones(ccType aCCType)
|
|
{
|
|
if (!mJSContext) {
|
|
return false;
|
|
}
|
|
|
|
MOZ_ASSERT(mUnmergedNeeded <= kMinConsecutiveUnmerged);
|
|
MOZ_ASSERT(mMergedInARow <= kMaxConsecutiveMerged);
|
|
|
|
if (mMergedInARow == kMaxConsecutiveMerged) {
|
|
MOZ_ASSERT(mUnmergedNeeded == 0);
|
|
mUnmergedNeeded = kMinConsecutiveUnmerged;
|
|
}
|
|
|
|
if (mUnmergedNeeded > 0) {
|
|
mUnmergedNeeded--;
|
|
mMergedInARow = 0;
|
|
return false;
|
|
}
|
|
|
|
if (aCCType == SliceCC && mJSContext->UsefulToMergeZones()) {
|
|
mMergedInARow++;
|
|
return true;
|
|
} else {
|
|
mMergedInARow = 0;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::BeginCollection(ccType aCCType,
|
|
nsICycleCollectorListener* aManualListener)
|
|
{
|
|
TimeLog timeLog;
|
|
MOZ_ASSERT(IsIdle());
|
|
|
|
mCollectionStart = TimeStamp::Now();
|
|
|
|
if (mJSContext) {
|
|
mJSContext->BeginCycleCollectionCallback();
|
|
timeLog.Checkpoint("BeginCycleCollectionCallback()");
|
|
}
|
|
|
|
bool isShutdown = (aCCType == ShutdownCC);
|
|
|
|
// Set up the listener for this CC.
|
|
MOZ_ASSERT_IF(isShutdown, !aManualListener);
|
|
MOZ_ASSERT(!mLogger, "Forgot to clear a previous listener?");
|
|
|
|
if (aManualListener) {
|
|
aManualListener->AsLogger(getter_AddRefs(mLogger));
|
|
}
|
|
|
|
aManualListener = nullptr;
|
|
if (!mLogger && mParams.LogThisCC(isShutdown)) {
|
|
mLogger = new nsCycleCollectorLogger();
|
|
if (mParams.AllTracesThisCC(isShutdown)) {
|
|
mLogger->SetAllTraces();
|
|
}
|
|
}
|
|
|
|
// On a WantAllTraces CC, force a synchronous global GC to prevent
|
|
// hijinks from ForgetSkippable and compartmental GCs.
|
|
bool forceGC = isShutdown || (mLogger && mLogger->IsAllTraces());
|
|
|
|
// BeginCycleCollectionCallback() might have started an IGC, and we need
|
|
// to finish it before we run FixGrayBits.
|
|
FinishAnyIncrementalGCInProgress();
|
|
timeLog.Checkpoint("Pre-FixGrayBits finish IGC");
|
|
|
|
FixGrayBits(forceGC, timeLog);
|
|
if (mJSContext) {
|
|
mJSContext->CheckGrayBits();
|
|
}
|
|
|
|
FreeSnowWhite(true);
|
|
timeLog.Checkpoint("BeginCollection FreeSnowWhite");
|
|
|
|
if (mLogger && NS_FAILED(mLogger->Begin())) {
|
|
mLogger = nullptr;
|
|
}
|
|
|
|
// FreeSnowWhite could potentially have started an IGC, which we need
|
|
// to finish before we look at any JS roots.
|
|
FinishAnyIncrementalGCInProgress();
|
|
timeLog.Checkpoint("Post-FreeSnowWhite finish IGC");
|
|
|
|
// Set up the data structures for building the graph.
|
|
JS::AutoAssertNoGC nogc;
|
|
JS::AutoEnterCycleCollection autocc(mJSContext->Context());
|
|
mGraph.Init();
|
|
mResults.Init();
|
|
mResults.mAnyManual = (aCCType != SliceCC);
|
|
bool mergeZones = ShouldMergeZones(aCCType);
|
|
mResults.mMergedZones = mergeZones;
|
|
|
|
MOZ_ASSERT(!mBuilder, "Forgot to clear mBuilder");
|
|
mBuilder = new CCGraphBuilder(mGraph, mResults, mJSContext, mLogger,
|
|
mergeZones);
|
|
timeLog.Checkpoint("BeginCollection prepare graph builder");
|
|
|
|
if (mJSContext) {
|
|
mJSContext->TraverseRoots(*mBuilder);
|
|
timeLog.Checkpoint("mJSContext->TraverseRoots()");
|
|
}
|
|
|
|
AutoRestore<bool> ar(mScanInProgress);
|
|
MOZ_RELEASE_ASSERT(!mScanInProgress);
|
|
mScanInProgress = true;
|
|
mPurpleBuf.SelectPointers(*mBuilder);
|
|
timeLog.Checkpoint("SelectPointers()");
|
|
|
|
mBuilder->DoneAddingRoots();
|
|
mIncrementalPhase = GraphBuildingPhase;
|
|
}
|
|
|
|
uint32_t
|
|
nsCycleCollector::SuspectedCount()
|
|
{
|
|
CheckThreadSafety();
|
|
return mPurpleBuf.Count();
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::Shutdown(bool aDoCollect)
|
|
{
|
|
CheckThreadSafety();
|
|
|
|
// Always delete snow white objects.
|
|
FreeSnowWhite(true);
|
|
|
|
if (aDoCollect) {
|
|
ShutdownCollect();
|
|
}
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::RemoveObjectFromGraph(void* aObj)
|
|
{
|
|
if (IsIdle()) {
|
|
return;
|
|
}
|
|
|
|
mGraph.RemoveObjectFromMap(aObj);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
|
|
size_t* aObjectSize,
|
|
size_t* aGraphSize,
|
|
size_t* aPurpleBufferSize) const
|
|
{
|
|
*aObjectSize = aMallocSizeOf(this);
|
|
|
|
*aGraphSize = mGraph.SizeOfExcludingThis(aMallocSizeOf);
|
|
|
|
*aPurpleBufferSize = mPurpleBuf.SizeOfExcludingThis(aMallocSizeOf);
|
|
|
|
// These fields are deliberately not measured:
|
|
// - mJSContext: because it's non-owning and measured by JS reporters.
|
|
// - mParams: because it only contains scalars.
|
|
}
|
|
|
|
JSPurpleBuffer*
|
|
nsCycleCollector::GetJSPurpleBuffer()
|
|
{
|
|
if (!mJSPurpleBuffer) {
|
|
// The Release call here confuses the GC analysis.
|
|
JS::AutoSuppressGCAnalysis nogc;
|
|
// JSPurpleBuffer keeps itself alive, but we need to create it in such way
|
|
// that it ends up in the normal purple buffer. That happens when
|
|
// nsRefPtr goes out of the scope and calls Release.
|
|
RefPtr<JSPurpleBuffer> pb = new JSPurpleBuffer(mJSPurpleBuffer);
|
|
}
|
|
return mJSPurpleBuffer;
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
// Module public API (exported in nsCycleCollector.h)
|
|
// Just functions that redirect into the singleton, once it's built.
|
|
////////////////////////////////////////////////////////////////////////
|
|
|
|
void
|
|
nsCycleCollector_registerJSContext(CycleCollectedJSContext* aCx)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
MOZ_ASSERT(data->mCollector);
|
|
// But we shouldn't already have a context.
|
|
MOZ_ASSERT(!data->mContext);
|
|
|
|
data->mContext = aCx;
|
|
data->mCollector->RegisterJSContext(aCx);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_forgetJSContext()
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
// And we shouldn't have already forgotten our context.
|
|
MOZ_ASSERT(data->mContext);
|
|
|
|
// But it may have shutdown already.
|
|
if (data->mCollector) {
|
|
data->mCollector->ForgetJSContext();
|
|
data->mContext = nullptr;
|
|
} else {
|
|
data->mContext = nullptr;
|
|
delete data;
|
|
sCollectorData.set(nullptr);
|
|
}
|
|
}
|
|
|
|
/* static */ CycleCollectedJSContext*
|
|
CycleCollectedJSContext::Get()
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
if (data) {
|
|
return data->mContext;
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
MOZ_NEVER_INLINE static void
|
|
SuspectAfterShutdown(void* aPtr, nsCycleCollectionParticipant* aCp,
|
|
nsCycleCollectingAutoRefCnt* aRefCnt,
|
|
bool* aShouldDelete)
|
|
{
|
|
if (aRefCnt->get() == 0) {
|
|
if (!aShouldDelete) {
|
|
// The CC is shut down, so we can't be in the middle of an ICC.
|
|
CanonicalizeParticipant(&aPtr, &aCp);
|
|
aRefCnt->stabilizeForDeletion();
|
|
aCp->DeleteCycleCollectable(aPtr);
|
|
} else {
|
|
*aShouldDelete = true;
|
|
}
|
|
} else {
|
|
// Make sure we'll get called again.
|
|
aRefCnt->RemoveFromPurpleBuffer();
|
|
}
|
|
}
|
|
|
|
void
|
|
NS_CycleCollectorSuspect3(void* aPtr, nsCycleCollectionParticipant* aCp,
|
|
nsCycleCollectingAutoRefCnt* aRefCnt,
|
|
bool* aShouldDelete)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
|
|
if (MOZ_LIKELY(data->mCollector)) {
|
|
data->mCollector->Suspect(aPtr, aCp, aRefCnt);
|
|
return;
|
|
}
|
|
SuspectAfterShutdown(aPtr, aCp, aRefCnt, aShouldDelete);
|
|
}
|
|
|
|
uint32_t
|
|
nsCycleCollector_suspectedCount()
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
|
|
if (!data->mCollector) {
|
|
return 0;
|
|
}
|
|
|
|
return data->mCollector->SuspectedCount();
|
|
}
|
|
|
|
bool
|
|
nsCycleCollector_init()
|
|
{
|
|
#ifdef DEBUG
|
|
static bool sInitialized;
|
|
|
|
MOZ_ASSERT(NS_IsMainThread(), "Wrong thread!");
|
|
MOZ_ASSERT(!sInitialized, "Called twice!?");
|
|
sInitialized = true;
|
|
#endif
|
|
|
|
return sCollectorData.init();
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_startup()
|
|
{
|
|
if (sCollectorData.get()) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
CollectorData* data = new CollectorData;
|
|
data->mCollector = new nsCycleCollector();
|
|
data->mContext = nullptr;
|
|
|
|
sCollectorData.set(data);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_setBeforeUnlinkCallback(CC_BeforeUnlinkCallback aCB)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
MOZ_ASSERT(data->mCollector);
|
|
|
|
data->mCollector->SetBeforeUnlinkCallback(aCB);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_setForgetSkippableCallback(CC_ForgetSkippableCallback aCB)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
MOZ_ASSERT(data->mCollector);
|
|
|
|
data->mCollector->SetForgetSkippableCallback(aCB);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_forgetSkippable(bool aRemoveChildlessNodes,
|
|
bool aAsyncSnowWhiteFreeing)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
MOZ_ASSERT(data->mCollector);
|
|
|
|
PROFILER_LABEL("nsCycleCollector", "forgetSkippable",
|
|
js::ProfileEntry::Category::CC);
|
|
|
|
TimeLog timeLog;
|
|
data->mCollector->ForgetSkippable(aRemoveChildlessNodes,
|
|
aAsyncSnowWhiteFreeing);
|
|
timeLog.Checkpoint("ForgetSkippable()");
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_dispatchDeferredDeletion(bool aContinuation, bool aPurge)
|
|
{
|
|
CycleCollectedJSContext* cx = CycleCollectedJSContext::Get();
|
|
if (cx) {
|
|
cx->DispatchDeferredDeletion(aContinuation, aPurge);
|
|
}
|
|
}
|
|
|
|
bool
|
|
nsCycleCollector_doDeferredDeletion()
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
MOZ_ASSERT(data->mCollector);
|
|
MOZ_ASSERT(data->mContext);
|
|
|
|
return data->mCollector->FreeSnowWhite(false);
|
|
}
|
|
|
|
already_AddRefed<nsICycleCollectorLogSink>
|
|
nsCycleCollector_createLogSink()
|
|
{
|
|
nsCOMPtr<nsICycleCollectorLogSink> sink = new nsCycleCollectorLogSinkToFile();
|
|
return sink.forget();
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_collect(nsICycleCollectorListener* aManualListener)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
MOZ_ASSERT(data->mCollector);
|
|
|
|
PROFILER_LABEL("nsCycleCollector", "collect",
|
|
js::ProfileEntry::Category::CC);
|
|
|
|
SliceBudget unlimitedBudget = SliceBudget::unlimited();
|
|
data->mCollector->Collect(ManualCC, unlimitedBudget, aManualListener);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_collectSlice(SliceBudget& budget,
|
|
bool aPreferShorterSlices)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
// We should have started the cycle collector by now.
|
|
MOZ_ASSERT(data);
|
|
MOZ_ASSERT(data->mCollector);
|
|
|
|
PROFILER_LABEL("nsCycleCollector", "collectSlice",
|
|
js::ProfileEntry::Category::CC);
|
|
|
|
data->mCollector->Collect(SliceCC, budget, nullptr, aPreferShorterSlices);
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_prepareForGarbageCollection()
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
MOZ_ASSERT(data);
|
|
|
|
if (!data->mCollector) {
|
|
return;
|
|
}
|
|
|
|
data->mCollector->PrepareForGarbageCollection();
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_finishAnyCurrentCollection()
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
MOZ_ASSERT(data);
|
|
|
|
if (!data->mCollector) {
|
|
return;
|
|
}
|
|
|
|
data->mCollector->FinishAnyCurrentCollection();
|
|
}
|
|
|
|
void
|
|
nsCycleCollector_shutdown(bool aDoCollect)
|
|
{
|
|
CollectorData* data = sCollectorData.get();
|
|
|
|
if (data) {
|
|
MOZ_ASSERT(data->mCollector);
|
|
PROFILER_LABEL("nsCycleCollector", "shutdown",
|
|
js::ProfileEntry::Category::CC);
|
|
|
|
data->mCollector->Shutdown(aDoCollect);
|
|
data->mCollector = nullptr;
|
|
if (data->mContext) {
|
|
// Run any remaining tasks that may have been enqueued via
|
|
// RunInStableState during the final cycle collection.
|
|
data->mContext->ProcessStableStateQueue();
|
|
}
|
|
if (!data->mContext) {
|
|
delete data;
|
|
sCollectorData.set(nullptr);
|
|
}
|
|
}
|
|
}
|