gecko/xpcom/base/nsCycleCollector.cpp
Nicholas Nethercote dfda858e50 Bug 1096624 - Use a SegmentedArray in nsCycleCollector::CollectWhite. r=smaug.
This patch does the following.

- Moves the logic for computing the ideal capacity for a SegmentedArray out of
  SnowWhiteKiller into its own class, SegmentedArrayCapacity.

- Replaces the nsTArray in CollectWhite(), which can be very large and is
  complicit in ~1% of OOM crashes, with a SegmentedArray.

--HG--
extra : rebase_source : 732743311a08fcc3dfe43a1b308846b93d30e6ed
2014-11-11 16:02:34 -08:00

4288 lines
117 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//
// This file implements a garbage-cycle collector based on the paper
//
// Concurrent Cycle Collection in Reference Counted Systems
// Bacon & Rajan (2001), ECOOP 2001 / Springer LNCS vol 2072
//
// We are not using the concurrent or acyclic cases of that paper; so
// the green, red and orange colors are not used.
//
// The collector is based on tracking pointers of four colors:
//
// Black nodes are definitely live. If we ever determine a node is
// black, it's ok to forget about, drop from our records.
//
// White nodes are definitely garbage cycles. Once we finish with our
// scanning, we unlink all the white nodes and expect that by
// unlinking them they will self-destruct (since a garbage cycle is
// only keeping itself alive with internal links, by definition).
//
// Snow-white is an addition to the original algorithm. Snow-white object
// has reference count zero and is just waiting for deletion.
//
// Grey nodes are being scanned. Nodes that turn grey will turn
// either black if we determine that they're live, or white if we
// determine that they're a garbage cycle. After the main collection
// algorithm there should be no grey nodes.
//
// Purple nodes are *candidates* for being scanned. They are nodes we
// haven't begun scanning yet because they're not old enough, or we're
// still partway through the algorithm.
//
// XPCOM objects participating in garbage-cycle collection are obliged
// to inform us when they ought to turn purple; that is, when their
// refcount transitions from N+1 -> N, for nonzero N. Furthermore we
// require that *after* an XPCOM object has informed us of turning
// purple, they will tell us when they either transition back to being
// black (incremented refcount) or are ultimately deleted.
// Incremental cycle collection
//
// Beyond the simple state machine required to implement incremental
// collection, the CC needs to be able to compensate for things the browser
// is doing during the collection. There are two kinds of problems. For each
// of these, there are two cases to deal with: purple-buffered C++ objects
// and JS objects.
// The first problem is that an object in the CC's graph can become garbage.
// This is bad because the CC touches the objects in its graph at every
// stage of its operation.
//
// All cycle collected C++ objects that die during a cycle collection
// will end up actually getting deleted by the SnowWhiteKiller. Before
// the SWK deletes an object, it checks if an ICC is running, and if so,
// if the object is in the graph. If it is, the CC clears mPointer and
// mParticipant so it does not point to the raw object any more. Because
// objects could die any time the CC returns to the mutator, any time the CC
// accesses a PtrInfo it must perform a null check on mParticipant to
// ensure the object has not gone away.
//
// JS objects don't always run finalizers, so the CC can't remove them from
// the graph when they die. Fortunately, JS objects can only die during a GC,
// so if a GC is begun during an ICC, the browser synchronously finishes off
// the ICC, which clears the entire CC graph. If the GC and CC are scheduled
// properly, this should be rare.
//
// The second problem is that objects in the graph can be changed, say by
// being addrefed or released, or by having a field updated, after the object
// has been added to the graph. The problem is that ICC can miss a newly
// created reference to an object, and end up unlinking an object that is
// actually alive.
//
// The basic idea of the solution, from "An on-the-fly Reference Counting
// Garbage Collector for Java" by Levanoni and Petrank, is to notice if an
// object has had an additional reference to it created during the collection,
// and if so, don't collect it during the current collection. This avoids having
// to rerun the scan as in Bacon & Rajan 2001.
//
// For cycle collected C++ objects, we modify AddRef to place the object in
// the purple buffer, in addition to Release. Then, in the CC, we treat any
// objects in the purple buffer as being alive, after graph building has
// completed. Because they are in the purple buffer, they will be suspected
// in the next CC, so there's no danger of leaks. This is imprecise, because
// we will treat as live an object that has been Released but not AddRefed
// during graph building, but that's probably rare enough that the additional
// bookkeeping overhead is not worthwhile.
//
// For JS objects, the cycle collector is only looking at gray objects. If a
// gray object is touched during ICC, it will be made black by UnmarkGray.
// Thus, if a JS object has become black during the ICC, we treat it as live.
// Merged JS zones have to be handled specially: we scan all zone globals.
// If any are black, we treat the zone as being black.
// Safety
//
// An XPCOM object is either scan-safe or scan-unsafe, purple-safe or
// purple-unsafe.
//
// An nsISupports object is scan-safe if:
//
// - It can be QI'ed to |nsXPCOMCycleCollectionParticipant|, though
// this operation loses ISupports identity (like nsIClassInfo).
// - Additionally, the operation |traverse| on the resulting
// nsXPCOMCycleCollectionParticipant does not cause *any* refcount
// adjustment to occur (no AddRef / Release calls).
//
// A non-nsISupports ("native") object is scan-safe by explicitly
// providing its nsCycleCollectionParticipant.
//
// An object is purple-safe if it satisfies the following properties:
//
// - The object is scan-safe.
//
// When we receive a pointer |ptr| via
// |nsCycleCollector::suspect(ptr)|, we assume it is purple-safe. We
// can check the scan-safety, but have no way to ensure the
// purple-safety; objects must obey, or else the entire system falls
// apart. Don't involve an object in this scheme if you can't
// guarantee its purple-safety. The easiest way to ensure that an
// object is purple-safe is to use nsCycleCollectingAutoRefCnt.
//
// When we have a scannable set of purple nodes ready, we begin
// our walks. During the walks, the nodes we |traverse| should only
// feed us more scan-safe nodes, and should not adjust the refcounts
// of those nodes.
//
// We do not |AddRef| or |Release| any objects during scanning. We
// rely on the purple-safety of the roots that call |suspect| to
// hold, such that we will clear the pointer from the purple buffer
// entry to the object before it is destroyed. The pointers that are
// merely scan-safe we hold only for the duration of scanning, and
// there should be no objects released from the scan-safe set during
// the scan.
//
// We *do* call |Root| and |Unroot| on every white object, on
// either side of the calls to |Unlink|. This keeps the set of white
// objects alive during the unlinking.
//
#if !defined(__MINGW32__)
#ifdef WIN32
#include <crtdbg.h>
#include <errno.h>
#endif
#endif
#include "base/process_util.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/AutoRestore.h"
#include "mozilla/CycleCollectedJSRuntime.h"
#include "mozilla/HoldDropJSObjects.h"
/* This must occur *after* base/process_util.h to avoid typedefs conflicts. */
#include "mozilla/MemoryReporting.h"
#include "mozilla/LinkedList.h"
#include "nsCycleCollectionParticipant.h"
#include "nsCycleCollectionNoteRootCallback.h"
#include "nsDeque.h"
#include "nsCycleCollector.h"
#include "nsThreadUtils.h"
#include "nsXULAppAPI.h"
#include "prenv.h"
#include "nsPrintfCString.h"
#include "nsTArray.h"
#include "nsIConsoleService.h"
#include "mozilla/Attributes.h"
#include "nsICycleCollectorListener.h"
#include "nsIMemoryReporter.h"
#include "nsIFile.h"
#include "nsDumpUtils.h"
#include "xpcpublic.h"
#include "GeckoProfiler.h"
#include <stdint.h>
#include <stdio.h>
#include "mozilla/Likely.h"
#include "mozilla/PoisonIOInterposer.h"
#include "mozilla/Telemetry.h"
#include "mozilla/ThreadLocal.h"
using namespace mozilla;
//#define COLLECT_TIME_DEBUG
// Enable assertions that are useful for diagnosing errors in graph construction.
//#define DEBUG_CC_GRAPH
#define DEFAULT_SHUTDOWN_COLLECTIONS 5
// One to do the freeing, then another to detect there is no more work to do.
#define NORMAL_SHUTDOWN_COLLECTIONS 2
// Cycle collector environment variables
//
// MOZ_CC_LOG_ALL: If defined, always log cycle collector heaps.
//
// MOZ_CC_LOG_SHUTDOWN: If defined, log cycle collector heaps at shutdown.
//
// MOZ_CC_LOG_THREAD: If set to "main", only automatically log main thread
// CCs. If set to "worker", only automatically log worker CCs. If set to "all",
// log either. The default value is "all". This must be used with either
// MOZ_CC_LOG_ALL or MOZ_CC_LOG_SHUTDOWN for it to do anything.
//
// MOZ_CC_LOG_PROCESS: If set to "main", only automatically log main process
// CCs. If set to "content", only automatically log tab CCs. If set to
// "plugins", only automatically log plugin CCs. If set to "all", log
// everything. The default value is "all". This must be used with either
// MOZ_CC_LOG_ALL or MOZ_CC_LOG_SHUTDOWN for it to do anything.
//
// MOZ_CC_ALL_TRACES: If set to "all", any cycle collector
// logging done will be WantAllTraces, which disables
// various cycle collector optimizations to give a fuller picture of
// the heap. If set to "shutdown", only shutdown logging will be WantAllTraces.
// The default is none.
//
// MOZ_CC_RUN_DURING_SHUTDOWN: In non-DEBUG or builds, if this is set,
// run cycle collections at shutdown.
//
// MOZ_CC_LOG_DIRECTORY: The directory in which logs are placed (such as
// logs from MOZ_CC_LOG_ALL and MOZ_CC_LOG_SHUTDOWN, or other uses
// of nsICycleCollectorListener)
// Various parameters of this collector can be tuned using environment
// variables.
struct nsCycleCollectorParams
{
bool mLogAll;
bool mLogShutdown;
bool mAllTracesAll;
bool mAllTracesShutdown;
bool mLogThisThread;
nsCycleCollectorParams() :
mLogAll(PR_GetEnv("MOZ_CC_LOG_ALL") != nullptr),
mLogShutdown(PR_GetEnv("MOZ_CC_LOG_SHUTDOWN") != nullptr),
mAllTracesAll(false),
mAllTracesShutdown(false)
{
const char* logThreadEnv = PR_GetEnv("MOZ_CC_LOG_THREAD");
bool threadLogging = true;
if (logThreadEnv && !!strcmp(logThreadEnv, "all")) {
if (NS_IsMainThread()) {
threadLogging = !strcmp(logThreadEnv, "main");
} else {
threadLogging = !strcmp(logThreadEnv, "worker");
}
}
const char* logProcessEnv = PR_GetEnv("MOZ_CC_LOG_PROCESS");
bool processLogging = true;
if (logProcessEnv && !!strcmp(logProcessEnv, "all")) {
switch (XRE_GetProcessType()) {
case GeckoProcessType_Default:
processLogging = !strcmp(logProcessEnv, "main");
break;
case GeckoProcessType_Plugin:
processLogging = !strcmp(logProcessEnv, "plugins");
break;
case GeckoProcessType_Content:
processLogging = !strcmp(logProcessEnv, "content");
break;
default:
processLogging = false;
break;
}
}
mLogThisThread = threadLogging && processLogging;
const char* allTracesEnv = PR_GetEnv("MOZ_CC_ALL_TRACES");
if (allTracesEnv) {
if (!strcmp(allTracesEnv, "all")) {
mAllTracesAll = true;
} else if (!strcmp(allTracesEnv, "shutdown")) {
mAllTracesShutdown = true;
}
}
}
bool LogThisCC(bool aIsShutdown)
{
return (mLogAll || (aIsShutdown && mLogShutdown)) && mLogThisThread;
}
bool AllTracesThisCC(bool aIsShutdown)
{
return mAllTracesAll || (aIsShutdown && mAllTracesShutdown);
}
};
#ifdef COLLECT_TIME_DEBUG
class TimeLog
{
public:
TimeLog() : mLastCheckpoint(TimeStamp::Now())
{
}
void
Checkpoint(const char* aEvent)
{
TimeStamp now = TimeStamp::Now();
double dur = (now - mLastCheckpoint).ToMilliseconds();
if (dur >= 0.5) {
printf("cc: %s took %.1fms\n", aEvent, dur);
}
mLastCheckpoint = now;
}
private:
TimeStamp mLastCheckpoint;
};
#else
class TimeLog
{
public:
TimeLog()
{
}
void Checkpoint(const char* aEvent)
{
}
};
#endif
////////////////////////////////////////////////////////////////////////
// Base types
////////////////////////////////////////////////////////////////////////
struct PtrInfo;
class EdgePool
{
public:
// EdgePool allocates arrays of void*, primarily to hold PtrInfo*.
// However, at the end of a block, the last two pointers are a null
// and then a void** pointing to the next block. This allows
// EdgePool::Iterators to be a single word but still capable of crossing
// block boundaries.
EdgePool()
{
mSentinelAndBlocks[0].block = nullptr;
mSentinelAndBlocks[1].block = nullptr;
}
~EdgePool()
{
MOZ_ASSERT(!mSentinelAndBlocks[0].block &&
!mSentinelAndBlocks[1].block,
"Didn't call Clear()?");
}
void Clear()
{
Block* b = Blocks();
while (b) {
Block* next = b->Next();
delete b;
b = next;
}
mSentinelAndBlocks[0].block = nullptr;
mSentinelAndBlocks[1].block = nullptr;
}
#ifdef DEBUG
bool IsEmpty()
{
return !mSentinelAndBlocks[0].block &&
!mSentinelAndBlocks[1].block;
}
#endif
private:
struct Block;
union PtrInfoOrBlock
{
// Use a union to avoid reinterpret_cast and the ensuing
// potential aliasing bugs.
PtrInfo* ptrInfo;
Block* block;
};
struct Block
{
enum { BlockSize = 16 * 1024 };
PtrInfoOrBlock mPointers[BlockSize];
Block()
{
mPointers[BlockSize - 2].block = nullptr; // sentinel
mPointers[BlockSize - 1].block = nullptr; // next block pointer
}
Block*& Next()
{
return mPointers[BlockSize - 1].block;
}
PtrInfoOrBlock* Start()
{
return &mPointers[0];
}
PtrInfoOrBlock* End()
{
return &mPointers[BlockSize - 2];
}
};
// Store the null sentinel so that we can have valid iterators
// before adding any edges and without adding any blocks.
PtrInfoOrBlock mSentinelAndBlocks[2];
Block*& Blocks()
{
return mSentinelAndBlocks[1].block;
}
Block* Blocks() const
{
return mSentinelAndBlocks[1].block;
}
public:
class Iterator
{
public:
Iterator() : mPointer(nullptr) {}
explicit Iterator(PtrInfoOrBlock* aPointer) : mPointer(aPointer) {}
Iterator(const Iterator& aOther) : mPointer(aOther.mPointer) {}
Iterator& operator++()
{
if (!mPointer->ptrInfo) {
// Null pointer is a sentinel for link to the next block.
mPointer = (mPointer + 1)->block->mPointers;
}
++mPointer;
return *this;
}
PtrInfo* operator*() const
{
if (!mPointer->ptrInfo) {
// Null pointer is a sentinel for link to the next block.
return (mPointer + 1)->block->mPointers->ptrInfo;
}
return mPointer->ptrInfo;
}
bool operator==(const Iterator& aOther) const
{
return mPointer == aOther.mPointer;
}
bool operator!=(const Iterator& aOther) const
{
return mPointer != aOther.mPointer;
}
#ifdef DEBUG_CC_GRAPH
bool Initialized() const
{
return mPointer != nullptr;
}
#endif
private:
PtrInfoOrBlock* mPointer;
};
class Builder;
friend class Builder;
class Builder
{
public:
explicit Builder(EdgePool& aPool)
: mCurrent(&aPool.mSentinelAndBlocks[0])
, mBlockEnd(&aPool.mSentinelAndBlocks[0])
, mNextBlockPtr(&aPool.Blocks())
{
}
Iterator Mark()
{
return Iterator(mCurrent);
}
void Add(PtrInfo* aEdge)
{
if (mCurrent == mBlockEnd) {
Block* b = new Block();
*mNextBlockPtr = b;
mCurrent = b->Start();
mBlockEnd = b->End();
mNextBlockPtr = &b->Next();
}
(mCurrent++)->ptrInfo = aEdge;
}
private:
// mBlockEnd points to space for null sentinel
PtrInfoOrBlock* mCurrent;
PtrInfoOrBlock* mBlockEnd;
Block** mNextBlockPtr;
};
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
{
size_t n = 0;
Block* b = Blocks();
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::Block'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
* that allocates the PtrInfo 32K-at-a-time.
*/
class NodePool
{
private:
// The -2 allows us to use |BlockSize + 1| for |mEntries|, and fit |mNext|,
// all without causing slop.
enum { BlockSize = 8 * 1024 - 2 };
struct Block
{
// We create and destroy Block using NS_Alloc/NS_Free rather
// than new and delete to avoid calling its constructor and
// destructor.
Block()
{
NS_NOTREACHED("should never be called");
// Ensure Block is the right size (see the comment on BlockSize above).
static_assert(
sizeof(Block) == 163824 || // 32-bit; equals 39.997 pages
sizeof(Block) == 262120, // 64-bit; equals 63.994 pages
"ill-sized NodePool::Block"
);
}
~Block()
{
NS_NOTREACHED("should never be called");
}
Block* mNext;
PtrInfo mEntries[BlockSize + 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()
{
Block* b = mBlocks;
while (b) {
Block* n = b->mNext;
NS_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) {
Block* block = static_cast<Block*>(NS_Alloc(sizeof(Block)));
*mNextBlock = block;
mNext = block->mEntries;
mBlockEnd = block->mEntries + BlockSize;
block->mNext = nullptr;
mNextBlock = &block->mNext;
}
return new (mNext++) PtrInfo(aPointer, aParticipant);
}
private:
Block** 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) {
Block* nextBlock = mCurBlock ? mCurBlock->mNext : mFirstBlock;
mNext = nextBlock->mEntries;
mBlockEnd = mNext + BlockSize;
mCurBlock = nextBlock;
}
return mNext++;
}
private:
// mFirstBlock is a reference to allow an Enumerator to be constructed
// for an empty graph.
Block*& mFirstBlock;
Block* 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;
Block* b = mBlocks;
while (b) {
n += aMallocSizeOf(b);
b = b->mNext;
}
return n;
}
private:
Block* mBlocks;
PtrInfo* mLast;
};
// Declarations for mPtrToNodeMap.
struct PtrToNodeEntry : public PLDHashEntryHdr
{
// The key is mNode->mPointer
PtrInfo* mNode;
};
static bool
PtrToNodeMatchEntry(PLDHashTable* aTable,
const PLDHashEntryHdr* aEntry,
const void* aKey)
{
const PtrToNodeEntry* n = static_cast<const PtrToNodeEntry*>(aEntry);
return n->mNode->mPointer == aKey;
}
static PLDHashTableOps PtrNodeOps = {
PL_DHashAllocTable,
PL_DHashFreeTable,
PL_DHashVoidPtrKeyStub,
PtrToNodeMatchEntry,
PL_DHashMoveEntryStub,
PL_DHashClearEntryStub,
PL_DHashFinalizeStub,
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;
public:
CCGraph() : mRootCount(0)
{
mPtrToNodeMap.ops = nullptr;
}
~CCGraph()
{
if (mPtrToNodeMap.ops) {
PL_DHashTableFinish(&mPtrToNodeMap);
}
}
void Init()
{
MOZ_ASSERT(IsEmpty(), "Failed to call CCGraph::Clear");
PL_DHashTableInit(&mPtrToNodeMap, &PtrNodeOps, nullptr,
sizeof(PtrToNodeEntry), 16384);
}
void Clear()
{
mNodes.Clear();
mEdges.Clear();
mWeakMaps.Clear();
mRootCount = 0;
PL_DHashTableFinish(&mPtrToNodeMap);
mPtrToNodeMap.ops = nullptr;
}
#ifdef DEBUG
bool IsEmpty()
{
return mNodes.IsEmpty() && mEdges.IsEmpty() &&
mWeakMaps.IsEmpty() && mRootCount == 0 &&
!mPtrToNodeMap.ops;
}
#endif
PtrInfo* FindNode(void* aPtr);
PtrToNodeEntry* AddNodeToMap(void* aPtr);
void RemoveNodeFromMap(void* aPtr);
uint32_t MapCount() const
{
return mPtrToNodeMap.EntryCount();
}
void SizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
size_t* aNodesSize, size_t* aEdgesSize,
size_t* aWeakMapsSize) const
{
*aNodesSize = mNodes.SizeOfExcludingThis(aMallocSizeOf);
*aEdgesSize = mEdges.SizeOfExcludingThis(aMallocSizeOf);
// We don't measure what the WeakMappings point to, because the
// pointers are non-owning.
*aWeakMapsSize = mWeakMaps.SizeOfExcludingThis(aMallocSizeOf);
}
};
PtrInfo*
CCGraph::FindNode(void* aPtr)
{
PtrToNodeEntry* e =
static_cast<PtrToNodeEntry*>(PL_DHashTableOperate(&mPtrToNodeMap, aPtr,
PL_DHASH_LOOKUP));
if (!PL_DHASH_ENTRY_IS_BUSY(e)) {
return nullptr;
}
return e->mNode;
}
PtrToNodeEntry*
CCGraph::AddNodeToMap(void* aPtr)
{
PtrToNodeEntry* e =
static_cast<PtrToNodeEntry*>(PL_DHashTableOperate(&mPtrToNodeMap, aPtr,
PL_DHASH_ADD));
if (!e) {
// Caller should track OOMs
return nullptr;
}
return e;
}
void
CCGraph::RemoveNodeFromMap(void* aPtr)
{
PL_DHashTableOperate(&mPtrToNodeMap, aPtr, PL_DHASH_REMOVE);
}
static nsISupports*
CanonicalizeXPCOMParticipant(nsISupports* aIn)
{
nsISupports* out;
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 Block
{
Block* 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];
Block() : mNext(nullptr)
{
// Ensure Block is the right size (see above).
static_assert(
sizeof(Block) == 16384 || // 32-bit
sizeof(Block) == 32768, // 64-bit
"ill-sized nsPurpleBuffer::Block"
);
}
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;
Block mFirstBlock;
nsPurpleBufferEntry* mFreeList;
public:
nsPurpleBuffer()
{
InitBlocks();
}
~nsPurpleBuffer()
{
FreeBlocks();
}
template<class PurpleVisitor>
void VisitEntries(PurpleVisitor& aVisitor)
{
for (Block* b = &mFirstBlock; b; b = b->mNext) {
b->VisitEntries(*this, aVisitor);
}
}
void InitBlocks()
{
mCount = 0;
mFreeList = nullptr;
StartBlock(&mFirstBlock);
}
void StartBlock(Block* aBlock)
{
NS_ABORT_IF_FALSE(!mFreeList, "should not have free list");
// Put all the entries in the block on the free list.
nsPurpleBufferEntry* entries = aBlock->mEntries;
mFreeList = entries;
for (uint32_t i = 1; i < ArrayLength(aBlock->mEntries); ++i) {
entries[i - 1].mNextInFreeList =
(nsPurpleBufferEntry*)(uintptr_t(entries + i) | 1);
}
entries[ArrayLength(aBlock->mEntries) - 1].mNextInFreeList =
(nsPurpleBufferEntry*)1;
}
void FreeBlocks()
{
if (mCount > 0) {
UnmarkRemainingPurple(&mFirstBlock);
}
Block* b = mFirstBlock.mNext;
while (b) {
if (mCount > 0) {
UnmarkRemainingPurple(b);
}
Block* 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(Block* 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)) {
Block* b = new Block;
StartBlock(b);
// 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 Block* 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();
}
}
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. */
};
#ifdef MOZ_NUWA_PROCESS
#include "ipc/Nuwa.h"
#endif
////////////////////////////////////////////////////////////////////////
// Top level structure for the cycle collector.
////////////////////////////////////////////////////////////////////////
typedef js::SliceBudget SliceBudget;
class JSPurpleBuffer;
class nsCycleCollector : public nsIMemoryReporter
{
NS_DECL_ISUPPORTS
NS_DECL_NSIMEMORYREPORTER
bool mActivelyCollecting;
bool mFreeingSnowWhite;
// mScanInProgress should be false when we're collecting white objects.
bool mScanInProgress;
CycleCollectorResults mResults;
TimeStamp mCollectionStart;
CycleCollectedJSRuntime* mJSRuntime;
ccPhase mIncrementalPhase;
CCGraph mGraph;
nsAutoPtr<CCGraphBuilder> mBuilder;
nsAutoPtr<NodePool::Enumerator> mCurrNode;
nsCOMPtr<nsICycleCollectorListener> mListener;
nsIThread* mThread;
nsCycleCollectorParams mParams;
uint32_t mWhiteNodeCount;
CC_BeforeUnlinkCallback mBeforeUnlinkCB;
CC_ForgetSkippableCallback mForgetSkippableCB;
nsPurpleBuffer mPurpleBuf;
uint32_t mUnmergedNeeded;
uint32_t mMergedInARow;
JSPurpleBuffer* mJSPurpleBuffer;
private:
virtual ~nsCycleCollector();
public:
nsCycleCollector();
void RegisterJSRuntime(CycleCollectedJSRuntime* aJSRuntime);
void ForgetJSRuntime();
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);
void Shutdown();
void SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
size_t* aObjectSize,
size_t* aGraphNodesSize,
size_t* aGraphEdgesSize,
size_t* aWeakMapsSize,
size_t* aPurpleBufferSize) const;
JSPurpleBuffer* GetJSPurpleBuffer();
private:
void CheckThreadSafety();
void ShutdownCollect();
void FixGrayBits(bool aForceGC);
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_t())) {
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
{
nsRefPtr<nsCycleCollector> mCollector;
CycleCollectedJSRuntime* mRuntime;
};
static mozilla::ThreadLocal<CollectorData*> sCollectorData;
////////////////////////////////////////////////////////////////////////
// Utility functions
////////////////////////////////////////////////////////////////////////
MOZ_NEVER_INLINE static void
Fault(const char* aMsg, const void* aPtr = nullptr)
{
if (aPtr) {
printf("Fault in cycle collector: %s (ptr: %p)\n", aMsg, aPtr);
} else {
printf("Fault in cycle collector: %s\n", aMsg);
}
NS_RUNTIMEABORT("cycle collector fault");
}
static void
Fault(const char* aMsg, PtrInfo* aPi)
{
Fault(aMsg, aPi->mPointer);
}
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.
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 nsCycleCollectorLogSinkToFile MOZ_FINAL : public nsICycleCollectorLogSink
{
public:
NS_DECL_ISUPPORTS
nsCycleCollectorLogSinkToFile() :
mProcessIdentifier(base::GetCurrentProcId()),
mGCLog("gc-edges"), mCCLog("cc-edges")
{
}
NS_IMETHOD GetFilenameIdentifier(nsAString& aIdentifier) MOZ_OVERRIDE
{
aIdentifier = mFilenameIdentifier;
return NS_OK;
}
NS_IMETHOD SetFilenameIdentifier(const nsAString& aIdentifier) MOZ_OVERRIDE
{
mFilenameIdentifier = aIdentifier;
return NS_OK;
}
NS_IMETHOD GetProcessIdentifier(int32_t* aIdentifier) MOZ_OVERRIDE
{
*aIdentifier = mProcessIdentifier;
return NS_OK;
}
NS_IMETHOD SetProcessIdentifier(int32_t aIdentifier) MOZ_OVERRIDE
{
mProcessIdentifier = aIdentifier;
return NS_OK;
}
NS_IMETHOD GetGcLog(nsIFile** aPath) MOZ_OVERRIDE
{
NS_IF_ADDREF(*aPath = mGCLog.mFile);
return NS_OK;
}
NS_IMETHOD GetCcLog(nsIFile** aPath) MOZ_OVERRIDE
{
NS_IF_ADDREF(*aPath = mCCLog.mFile);
return NS_OK;
}
NS_IMETHOD Open(FILE** aGCLog, FILE** aCCLog) MOZ_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() MOZ_OVERRIDE
{
if (!mGCLog.mStream) {
return NS_ERROR_UNEXPECTED;
}
CloseLog(&mGCLog, NS_LITERAL_STRING("Garbage"));
return NS_OK;
}
NS_IMETHOD CloseCCLog() MOZ_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);
aLog->mFile->OpenANSIFileDesc("w", &aLog->mStream);
if (NS_WARN_IF(!aLog->mStream)) {
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.
nsCOMPtr<nsIConsoleService> cs =
do_GetService(NS_CONSOLESERVICE_CONTRACTID);
if (cs) {
// Copy out the path.
nsAutoString logPath;
logFileFinalDestination->GetPath(logPath);
nsString msg = aCollectorKind +
NS_LITERAL_STRING(" Collector log dumped to ") + logPath;
cs->LogStringMessage(msg.get());
}
return NS_OK;
}
int32_t mProcessIdentifier;
nsString mFilenameIdentifier;
FileInfo mGCLog;
FileInfo mCCLog;
};
NS_IMPL_ISUPPORTS(nsCycleCollectorLogSinkToFile, nsICycleCollectorLogSink)
class nsCycleCollectorLogger MOZ_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;
}
NS_IMETHOD AllTraces(nsICycleCollectorListener** aListener)
{
SetAllTraces();
NS_ADDREF(*aListener = this);
return NS_OK;
}
NS_IMETHOD GetWantAllTraces(bool* aAllTraces)
{
*aAllTraces = mWantAllTraces;
return NS_OK;
}
NS_IMETHOD GetDisableLog(bool* aDisableLog)
{
*aDisableLog = mDisableLog;
return NS_OK;
}
NS_IMETHOD SetDisableLog(bool aDisableLog)
{
mDisableLog = aDisableLog;
return NS_OK;
}
NS_IMETHOD GetWantAfterProcessing(bool* aWantAfterProcessing)
{
*aWantAfterProcessing = mWantAfterProcessing;
return NS_OK;
}
NS_IMETHOD SetWantAfterProcessing(bool aWantAfterProcessing)
{
mWantAfterProcessing = aWantAfterProcessing;
return NS_OK;
}
NS_IMETHOD GetLogSink(nsICycleCollectorLogSink** aLogSink)
{
NS_ADDREF(*aLogSink = mLogSink);
return NS_OK;
}
NS_IMETHOD SetLogSink(nsICycleCollectorLogSink* aLogSink)
{
if (!aLogSink) {
return NS_ERROR_INVALID_ARG;
}
mLogSink = aLogSink;
return NS_OK;
}
NS_IMETHOD 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->mRuntime) {
data->mRuntime->DumpJSHeap(gcLog);
}
rv = mLogSink->CloseGCLog();
NS_ENSURE_SUCCESS(rv, rv);
fprintf(mCCLog, "# WantAllTraces=%s\n", mWantAllTraces ? "true" : "false");
return NS_OK;
}
NS_IMETHOD 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);
}
return NS_OK;
}
NS_IMETHOD 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);
}
}
return NS_OK;
}
NS_IMETHOD 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);
}
return NS_OK;
}
NS_IMETHOD 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.
return NS_OK;
}
NS_IMETHOD NoteIncrementalRoot(uint64_t aAddress)
{
if (!mDisableLog) {
fprintf(mCCLog, "IncrementalRoot %p\n", (void*)aAddress);
}
// We don't support after-processing for incremental roots.
return NS_OK;
}
NS_IMETHOD BeginResults()
{
if (!mDisableLog) {
fputs("==========\n", mCCLog);
}
return NS_OK;
}
NS_IMETHOD 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;
}
return NS_OK;
}
NS_IMETHOD 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);
}
return NS_OK;
}
NS_IMETHOD End()
{
if (!mDisableLog) {
mCCLog = nullptr;
nsresult rv = mLogSink->CloseCCLog();
NS_ENSURE_SUCCESS(rv, rv);
}
return NS_OK;
}
NS_IMETHOD ProcessNext(nsICycleCollectorHandler* aHandler,
bool* aCanContinue)
{
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;
}
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);
}
////////////////////////////////////////////////////////////////////////
// Bacon & Rajan's |MarkRoots| routine.
////////////////////////////////////////////////////////////////////////
class CCGraphBuilder MOZ_FINAL : public nsCycleCollectionTraversalCallback,
public nsCycleCollectionNoteRootCallback
{
private:
CCGraph& mGraph;
CycleCollectorResults& mResults;
NodePool::Builder mNodeBuilder;
EdgePool::Builder mEdgeBuilder;
PtrInfo* mCurrPi;
nsCycleCollectionParticipant* mJSParticipant;
nsCycleCollectionParticipant* mJSZoneParticipant;
nsCString mNextEdgeName;
nsICycleCollectorListener* mListener;
bool mMergeZones;
bool mRanOutOfMemory;
public:
CCGraphBuilder(CCGraph& aGraph,
CycleCollectorResults& aResults,
CycleCollectedJSRuntime* aJSRuntime,
nsICycleCollectorListener* aListener,
bool aMergeZones);
virtual ~CCGraphBuilder();
bool WantAllTraces() const
{
return nsCycleCollectionNoteRootCallback::WantAllTraces();
}
PtrInfo* AddNode(void* aPtr, nsCycleCollectionParticipant* aParticipant);
PtrInfo* AddWeakMapNode(void* aNode);
void Traverse(PtrInfo* aPtrInfo);
void SetLastChild();
bool RanOutOfMemory() const
{
return mRanOutOfMemory;
}
private:
void DescribeNode(uint32_t aRefCount, const char* aObjName)
{
mCurrPi->mRefCount = aRefCount;
}
public:
// nsCycleCollectionNoteRootCallback methods.
NS_IMETHOD_(void) NoteXPCOMRoot(nsISupports* aRoot);
NS_IMETHOD_(void) NoteJSRoot(void* aRoot);
NS_IMETHOD_(void) NoteNativeRoot(void* aRoot,
nsCycleCollectionParticipant* aParticipant);
NS_IMETHOD_(void) NoteWeakMapping(void* aMap, void* aKey, void* aKdelegate,
void* 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(void* aChild);
NS_IMETHOD_(void) NoteNativeChild(void* aChild,
nsCycleCollectionParticipant* aParticipant);
NS_IMETHOD_(void) NoteNextEdgeName(const char* aName);
private:
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 (mListener) {
mListener->NoteEdge((uint64_t)aChild, aEdgeName.get());
}
++childPi->mInternalRefs;
}
JS::Zone* MergeZone(void* 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,
CycleCollectedJSRuntime* aJSRuntime,
nsICycleCollectorListener* aListener,
bool aMergeZones)
: mGraph(aGraph)
, mResults(aResults)
, mNodeBuilder(aGraph.mNodes)
, mEdgeBuilder(aGraph.mEdges)
, mJSParticipant(nullptr)
, mJSZoneParticipant(nullptr)
, mListener(aListener)
, mMergeZones(aMergeZones)
, mRanOutOfMemory(false)
{
if (aJSRuntime) {
mJSParticipant = aJSRuntime->GCThingParticipant();
mJSZoneParticipant = aJSRuntime->ZoneParticipant();
}
uint32_t flags = 0;
if (!flags && mListener) {
flags = nsCycleCollectionTraversalCallback::WANT_DEBUG_INFO;
bool all = false;
mListener->GetWantAllTraces(&all);
if (all) {
flags |= nsCycleCollectionTraversalCallback::WANT_ALL_TRACES;
mWantAllTraces = true; // for nsCycleCollectionNoteRootCallback
}
}
mFlags |= flags;
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) {
mRanOutOfMemory = true;
return nullptr;
}
PtrInfo* result;
if (!e->mNode) {
// New entry.
result = mNodeBuilder.Add(aPtr, aParticipant);
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;
}
MOZ_NEVER_INLINE void
CCGraphBuilder::Traverse(PtrInfo* aPtrInfo)
{
mCurrPi = aPtrInfo;
mCurrPi->SetFirstChild(mEdgeBuilder.Mark());
if (!aPtrInfo->mParticipant) {
return;
}
nsresult rv = aPtrInfo->mParticipant->Traverse(aPtrInfo->mPointer, *this);
if (NS_FAILED(rv)) {
Fault("script pointer traversal failed", aPtrInfo);
}
}
void
CCGraphBuilder::SetLastChild()
{
mCurrPi->SetLastChild(mEdgeBuilder.Mark());
}
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(void* aRoot)
{
if (JS::Zone* zone = MergeZone(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)
{
if (aRefCount == 0) {
Fault("zero refcount", mCurrPi);
}
if (aRefCount == UINT32_MAX) {
Fault("overflowing refcount", mCurrPi);
}
mResults.mVisitedRefCounted++;
if (mListener) {
mListener->NoteRefCountedObject((uint64_t)mCurrPi->mPointer, aRefCount,
aObjName);
}
DescribeNode(aRefCount, aObjName);
}
NS_IMETHODIMP_(void)
CCGraphBuilder::DescribeGCedNode(bool aIsMarked, const char* aObjName,
uint64_t aCompartmentAddress)
{
uint32_t refCount = aIsMarked ? UINT32_MAX : 0;
mResults.mVisitedGCed++;
if (mListener) {
mListener->NoteGCedObject((uint64_t)mCurrPi->mPointer, aIsMarked,
aObjName, aCompartmentAddress);
}
DescribeNode(refCount, aObjName);
}
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!");
NoteChild(aChild, aParticipant, edgeName);
}
NS_IMETHODIMP_(void)
CCGraphBuilder::NoteJSChild(void* aChild)
{
if (!aChild) {
return;
}
nsCString edgeName;
if (MOZ_UNLIKELY(WantDebugInfo())) {
edgeName.Assign(mNextEdgeName);
mNextEdgeName.Truncate();
}
if (xpc_GCThingIsGrayCCThing(aChild) || MOZ_UNLIKELY(WantAllTraces())) {
if (JS::Zone* zone = MergeZone(aChild)) {
NoteChild(zone, mJSZoneParticipant, edgeName);
} else {
NoteChild(aChild, mJSParticipant, edgeName);
}
}
}
NS_IMETHODIMP_(void)
CCGraphBuilder::NoteNextEdgeName(const char* aName)
{
if (WantDebugInfo()) {
mNextEdgeName = aName;
}
}
PtrInfo*
CCGraphBuilder::AddWeakMapNode(void* aNode)
{
MOZ_ASSERT(aNode, "Weak map node should be non-null.");
if (!xpc_GCThingIsGrayCCThing(aNode) && !WantAllTraces()) {
return nullptr;
}
if (JS::Zone* zone = MergeZone(aNode)) {
return AddNode(zone, mJSZoneParticipant);
}
return AddNode(aNode, mJSParticipant);
}
NS_IMETHODIMP_(void)
CCGraphBuilder::NoteWeakMapping(void* aMap, void* aKey, void* aKdelegate,
void* 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 (mListener) {
mListener->NoteWeakMapEntry((uint64_t)aMap, (uint64_t)aKey,
(uint64_t)aKdelegate, (uint64_t)aVal);
}
}
static bool
AddPurpleRoot(CCGraphBuilder& aBuilder, void* aRoot,
nsCycleCollectionParticipant* aParti)
{
CanonicalizeParticipant(&aRoot, &aParti);
if (aBuilder.WantAllTraces() || !aParti->CanSkipInCC(aRoot)) {
PtrInfo* pinfo = aBuilder.AddNode(aRoot, aParti);
if (!pinfo) {
return false;
}
}
return true;
}
// 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(void* aChild);
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) {
mMayHaveChild = true;
}
}
NS_IMETHODIMP_(void)
ChildFinder::NoteJSChild(void* aChild)
{
if (aChild && xpc_GCThingIsGrayCCThing(aChild)) {
mMayHaveChild = true;
}
}
static bool
MayHaveChild(void* aObj, nsCycleCollectionParticipant* aCp)
{
ChildFinder cf;
aCp->Traverse(aObj, cf);
return cf.MayHaveChild();
}
template<class T, size_t N>
class SegmentedArrayElement
: public LinkedListElement<SegmentedArrayElement<T, N>>
, public AutoFallibleTArray<T, N>
{
};
// For a given segment size (in bytes), compute the number of T elements
// that can fit into it.
template<typename T, size_t IdealSegmentSize>
class SegmentedArrayCapacity
{
static const size_t kSingleElemSegmentSize =
sizeof(SegmentedArrayElement<T, 1>);
public:
static const size_t value =
(IdealSegmentSize - kSingleElemSegmentSize) / sizeof(T) + 1;
static const size_t kActualSegmentSize =
sizeof(SegmentedArrayElement<T, value>);
};
template<class T, size_t N>
class SegmentedArray
{
typedef SegmentedArrayElement<T, N> Segment;
public:
~SegmentedArray()
{
MOZ_ASSERT(IsEmpty());
}
void AppendElement(T& aElement)
{
Segment* last = mSegments.getLast();
if (!last || last->Length() == last->Capacity()) {
last = new Segment();
mSegments.insertBack(last);
}
last->AppendElement(aElement);
}
void Clear()
{
Segment* first;
while ((first = mSegments.popFirst())) {
delete first;
}
}
Segment* GetFirstSegment()
{
return mSegments.getFirst();
}
const Segment* GetFirstSegment() const
{
return mSegments.getFirst();
}
bool IsEmpty() const
{
return !GetFirstSegment();
}
private:
mozilla::LinkedList<Segment> mSegments;
};
// 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(JSPurpleBuffer*& aReferenceToThis)
: mReferenceToThis(aReferenceToThis)
{
mReferenceToThis = this;
NS_ADDREF_THIS();
mozilla::HoldJSObjects(this);
}
void Destroy()
{
mReferenceToThis = nullptr;
mValues.Clear();
mObjects.Clear();
mozilla::DropJSObjects(this);
NS_RELEASE_THIS();
}
NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(JSPurpleBuffer)
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(JSPurpleBuffer)
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.
SegmentedArray<JS::Value, 60> mValues;
SegmentedArray<JSObject*, 60> 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_SCRIPT_OBJECTS
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
#define NS_TRACE_SEGMENTED_ARRAY(_field, _type) \
{ \
auto segment = tmp->_field.GetFirstSegment(); \
while (segment) { \
for (uint32_t i = segment->Length(); i > 0;) { \
js::gc::CallTraceCallbackOnNonHeap<_type, TraceCallbacks>( \
&segment->ElementAt(--i), aCallbacks, #_field, aClosure); \
} \
segment = segment->getNext(); \
} \
}
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 kSegmentCapacity =
SegmentedArrayCapacity<SnowWhiteObject, sizeof(void*) * 1024>::value;
typedef SegmentedArray<SnowWhiteObject, kSegmentCapacity> ObjectsArray;
public:
SnowWhiteKiller(nsCycleCollector* aCollector, uint32_t aMaxCount)
: mCollector(aCollector)
, mObjects()
{
MOZ_ASSERT(mCollector, "Calling SnowWhiteKiller after nsCC went away");
}
~SnowWhiteKiller()
{
auto segment = mObjects.GetFirstSegment();
while (segment) {
for (uint32_t i = 0; i < segment->Length(); i++) {
SnowWhiteObject& o = segment->ElementAt(i);
if (!o.mRefCnt->get() && !o.mRefCnt->IsInPurpleBuffer()) {
mCollector->RemoveObjectFromGraph(o.mPointer);
o.mRefCnt->stabilizeForDeletion();
o.mParticipant->Trace(o.mPointer, *this, nullptr);
o.mParticipant->DeleteCycleCollectable(o.mPointer);
}
}
segment = segment->getNext();
}
mObjects.Clear();
}
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.AppendElement(swo);
aBuffer.Remove(aEntry);
}
}
bool HasSnowWhiteObjects() const
{
return !mObjects.IsEmpty();
}
virtual void Trace(JS::Heap<JS::Value>* aValue, const char* aName,
void* aClosure) const
{
JS::Value val = *aValue;
if (val.isMarkable()) {
void* thing = val.toGCThing();
if (thing && xpc_GCThingIsGrayCCThing(thing)) {
MOZ_ASSERT(!js::gc::IsInsideNursery((js::gc::Cell*)thing));
mCollector->GetJSPurpleBuffer()->mValues.AppendElement(val);
}
}
}
virtual void Trace(JS::Heap<jsid>* aId, const char* aName,
void* aClosure) const
{
}
void AppendJSObjectToPurpleBuffer(JSObject* obj) const
{
if (obj && xpc_GCThingIsGrayCCThing(obj)) {
MOZ_ASSERT(!js::gc::IsInsideNursery(JS::AsCell(obj)));
mCollector->GetJSPurpleBuffer()->mObjects.AppendElement(obj);
}
}
virtual void Trace(JS::Heap<JSObject*>* aObject, const char* aName,
void* aClosure) const
{
AppendJSObjectToPurpleBuffer(*aObject);
}
virtual void Trace(JS::TenuredHeap<JSObject*>* aObject, const char* aName,
void* aClosure) const
{
AppendJSObjectToPurpleBuffer(*aObject);
}
virtual void Trace(JS::Heap<JSString*>* aString, const char* aName,
void* aClosure) const
{
}
virtual void Trace(JS::Heap<JSScript*>* aScript, const char* aName,
void* aClosure) const
{
}
virtual void Trace(JS::Heap<JSFunction*>* aFunction, const char* aName,
void* aClosure) const
{
}
private:
nsCycleCollector* mCollector;
ObjectsArray mObjects;
};
class RemoveSkippableVisitor : public SnowWhiteKiller
{
public:
RemoveSkippableVisitor(nsCycleCollector* aCollector,
uint32_t aMaxCount, bool aRemoveChildlessNodes,
bool aAsyncSnowWhiteFreeing,
CC_ForgetSkippableCallback aCb)
: SnowWhiteKiller(aCollector, aAsyncSnowWhiteFreeing ? 0 : aMaxCount)
, 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, Count(), 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.Count());
mPurpleBuf.VisitEntries(visitor);
hadSnowWhiteObjects = hadSnowWhiteObjects ||
visitor.HasSnowWhiteObjects();
if (!visitor.HasSnowWhiteObjects()) {
break;
}
} while (aUntilNoSWInPurpleBuffer);
return hadSnowWhiteObjects;
}
void
nsCycleCollector::ForgetSkippable(bool aRemoveChildlessNodes,
bool aAsyncSnowWhiteFreeing)
{
CheckThreadSafety();
// 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(mIncrementalPhase == IdlePhase);
if (mJSRuntime) {
mJSRuntime->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)
{
const intptr_t kNumNodesBetweenTimeChecks = 1000;
const intptr_t kStep = SliceBudget::CounterReset / kNumNodesBetweenTimeChecks;
TimeLog timeLog;
AutoRestore<bool> ar(mScanInProgress);
MOZ_ASSERT(!mScanInProgress);
mScanInProgress = true;
MOZ_ASSERT(mIncrementalPhase == GraphBuildingPhase);
MOZ_ASSERT(mCurrNode);
while (!aBudget.isOverBudget() && !mCurrNode->IsDone()) {
PtrInfo* pi = mCurrNode->GetNext();
if (!pi) {
MOZ_CRASH();
}
// We need to call the builder's Traverse() method on deleted nodes, to
// set their firstChild() that may be read by a prior non-deleted
// neighbor.
mBuilder->Traverse(pi);
if (mCurrNode->AtBlockEnd()) {
mBuilder->SetLastChild();
}
aBudget.step(kStep);
}
if (!mCurrNode->IsDone()) {
timeLog.Checkpoint("MarkRoots()");
return;
}
if (mGraph.mRootCount > 0) {
mBuilder->SetLastChild();
}
if (mBuilder->RanOutOfMemory()) {
MOZ_ASSERT(false, "Ran out of memory while building cycle collector graph");
CC_TELEMETRY(_OOM, true);
}
mBuilder = nullptr;
mCurrNode = 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, nsICycleCollectorListener* aListener,
uint32_t& aCount, bool& aFailed)
: mGraph(aGraph), mListener(aListener), 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(mListener)) {
mListener->NoteIncrementalRoot((uint64_t)pi->mPointer);
}
if (pi->mColor == black) {
return;
}
FloodBlackNode(mCount, mFailed, pi);
}
private:
CCGraph& mGraph;
nsICycleCollectorListener* mListener;
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, mListener,
mWhiteNodeCount, failed);
mPurpleBuf.VisitEntries(purpleScanBlackVisitor);
timeLog.Checkpoint("ScanIncrementalRoots::fix purple");
bool hasJSRuntime = !!mJSRuntime;
nsCycleCollectionParticipant* jsParticipant =
hasJSRuntime ? mJSRuntime->GCThingParticipant() : nullptr;
nsCycleCollectionParticipant* zoneParticipant =
hasJSRuntime ? mJSRuntime->ZoneParticipant() : nullptr;
bool hasListener = !!mListener;
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(!hasListener)) {
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(hasJSRuntime)) {
// 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) {
if (xpc_GCThingIsGrayCCThing(pi->mPointer)) {
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(hasListener) && pi->mPointer) {
// Dead objects aren't logged. See bug 1031370.
mListener->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 (MOZ_LIKELY(pi->mInternalRefs < pi->mRefCount)) {
// This node will get marked black in the next pass.
continue;
}
Fault("Traversed refs exceed refcount", pi);
}
}
// 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)
{
AutoRestore<bool> ar(mScanInProgress);
MOZ_ASSERT(!mScanInProgress);
mScanInProgress = true;
mWhiteNodeCount = 0;
MOZ_ASSERT(mIncrementalPhase == ScanAndCollectWhitePhase);
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 (mListener) {
mListener->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) {
mListener->DescribeRoot((uint64_t)pi->mPointer,
pi->mInternalRefs);
}
break;
case white:
mListener->DescribeGarbage((uint64_t)pi->mPointer);
break;
case grey:
MOZ_ASSERT(false, "All traversed objects should be black or white");
break;
}
}
mListener->End();
mListener = 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 cap =
SegmentedArrayCapacity<PtrInfo*, sizeof(void*) * 1024>::value;
SegmentedArray<PtrInfo*, cap> whiteNodes;
TimeLog timeLog;
MOZ_ASSERT(mIncrementalPhase == ScanAndCollectWhitePhase);
uint32_t numWhiteNodes = 0;
uint32_t numWhiteGCed = 0;
uint32_t numWhiteJSZones = 0;
bool hasJSRuntime = !!mJSRuntime;
nsCycleCollectionParticipant* zoneParticipant =
hasJSRuntime ? mJSRuntime->ZoneParticipant() : nullptr;
NodePool::Enumerator etor(mGraph.mNodes);
while (!etor.IsDone()) {
PtrInfo* pinfo = etor.GetNext();
if (pinfo->mColor == white && pinfo->mParticipant) {
if (pinfo->IsGrayJS()) {
++numWhiteGCed;
if (MOZ_UNLIKELY(pinfo->mParticipant == zoneParticipant)) {
++numWhiteJSZones;
}
} else {
whiteNodes.AppendElement(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.
auto segment = whiteNodes.GetFirstSegment();
while (segment) {
for (uint32_t i = 0; i < segment->Length(); i++) {
PtrInfo* pinfo = segment->ElementAt(i);
MOZ_ASSERT(pinfo->mParticipant,
"Unlink shouldn't see objects removed from graph.");
pinfo->mParticipant->Unlink(pinfo->mPointer);
#ifdef DEBUG
if (mJSRuntime) {
mJSRuntime->AssertNoObjectsToTrace(pinfo->mPointer);
}
#endif
}
segment = segment->getNext();
}
timeLog.Checkpoint("CollectWhite::Unlink");
segment = whiteNodes.GetFirstSegment();
while (segment) {
for (uint32_t i = 0; i < segment->Length(); i++) {
PtrInfo* pinfo = segment->ElementAt(i);
MOZ_ASSERT(pinfo->mParticipant,
"Unroot shouldn't see objects removed from graph.");
pinfo->mParticipant->Unroot(pinfo->mPointer);
}
segment = segment->getNext();
}
timeLog.Checkpoint("CollectWhite::Unroot");
nsCycleCollector_dispatchDeferredDeletion(false);
timeLog.Checkpoint("CollectWhite::dispatchDeferredDeletion");
mIncrementalPhase = CleanupPhase;
whiteNodes.Clear();
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, graphNodesSize, graphEdgesSize, weakMapsSize,
purpleBufferSize;
SizeOfIncludingThis(CycleCollectorMallocSizeOf,
&objectSize,
&graphNodesSize, &graphEdgesSize,
&weakMapsSize,
&purpleBufferSize);
#define REPORT(_path, _amount, _desc) \
do { \
size_t amount = _amount; /* evaluate |_amount| only once */ \
if (amount > 0) { \
nsresult rv; \
rv = aHandleReport->Callback(EmptyCString(), \
NS_LITERAL_CSTRING(_path), \
KIND_HEAP, UNITS_BYTES, _amount, \
NS_LITERAL_CSTRING(_desc), \
aData); \
if (NS_WARN_IF(NS_FAILED(rv))) \
return rv; \
} \
} while (0)
REPORT("explicit/cycle-collector/collector-object", objectSize,
"Memory used for the cycle collector object itself.");
REPORT("explicit/cycle-collector/graph-nodes", graphNodesSize,
"Memory used for the nodes of the cycle collector's graph. "
"This should be zero when the collector is idle.");
REPORT("explicit/cycle-collector/graph-edges", graphEdgesSize,
"Memory used for the edges of the cycle collector's graph. "
"This should be zero when the collector is idle.");
REPORT("explicit/cycle-collector/weak-maps", weakMapsSize,
"Memory used for the representation of weak maps in the "
"cycle collector's graph. "
"This should be zero when the collector is idle.");
REPORT("explicit/cycle-collector/purple-buffer", purpleBufferSize,
"Memory used for the cycle collector's purple buffer.");
#undef REPORT
return NS_OK;
};
////////////////////////////////////////////////////////////////////////
// Collector implementation
////////////////////////////////////////////////////////////////////////
nsCycleCollector::nsCycleCollector() :
mActivelyCollecting(false),
mFreeingSnowWhite(false),
mScanInProgress(false),
mJSRuntime(nullptr),
mIncrementalPhase(IdlePhase),
mThread(NS_GetCurrentThread()),
mWhiteNodeCount(0),
mBeforeUnlinkCB(nullptr),
mForgetSkippableCB(nullptr),
mUnmergedNeeded(0),
mMergedInARow(0),
mJSPurpleBuffer(nullptr)
{
}
nsCycleCollector::~nsCycleCollector()
{
UnregisterWeakMemoryReporter(this);
}
void
nsCycleCollector::RegisterJSRuntime(CycleCollectedJSRuntime* aJSRuntime)
{
if (mJSRuntime) {
Fault("multiple registrations of cycle collector JS runtime", aJSRuntime);
}
mJSRuntime = aJSRuntime;
// 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.
static bool registered = false;
if (!registered) {
RegisterWeakMemoryReporter(this);
registered = true;
}
}
void
nsCycleCollector::ForgetJSRuntime()
{
if (!mJSRuntime) {
Fault("forgetting non-registered cycle collector JS runtime");
}
mJSRuntime = 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();
// Re-entering ::Suspect during collection used to be a fault, but
// we are canonicalizing nsISupports pointers using QI, so we will
// see some spurious refcount traffic here.
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 runtime 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)
{
CheckThreadSafety();
if (!mJSRuntime) {
return;
}
if (!aForceGC) {
mJSRuntime->FixWeakMappingGrayBits();
bool needGC = !mJSRuntime->AreGCGrayBitsValid();
// Only do a telemetry ping for non-shutdown CCs.
CC_TELEMETRY(_NEED_GC, needGC);
if (!needGC) {
return;
}
mResults.mForcedGC = true;
}
TimeLog timeLog;
mJSRuntime->GarbageCollect(aForceGC ? JS::gcreason::SHUTDOWN_CC :
JS::gcreason::CC_FORCED);
timeLog.Checkpoint("GC()");
}
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 (mJSRuntime) {
mJSRuntime->EndCycleCollectionCallback(mResults);
timeLog.Checkpoint("CleanupAfterCollection::EndCycleCollectionCallback()");
}
mIncrementalPhase = IdlePhase;
}
void
nsCycleCollector::ShutdownCollect()
{
SliceBudget unlimitedBudget;
uint32_t i;
for (i = 0; i < DEFAULT_SHUTDOWN_COLLECTIONS; ++i) {
if (!Collect(ShutdownCC, unlimitedBudget, nullptr)) {
break;
}
}
NS_WARN_IF_FALSE(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)
{
CheckThreadSafety();
// This can legitimately happen in a few cases. See bug 383651.
if (mActivelyCollecting || mFreeingSnowWhite) {
return false;
}
mActivelyCollecting = true;
bool startedIdle = (mIncrementalPhase == IdlePhase);
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");
}
++mResults.mNumSlices;
bool continueSlice = true;
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;
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(mIncrementalPhase == IdlePhase);
if (Collect(aCCType, aBudget, aManualListener)) {
collectedAny = true;
}
}
MOZ_ASSERT_IF(aCCType != SliceCC, mIncrementalPhase == IdlePhase);
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 (mIncrementalPhase == IdlePhase) {
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 (mIncrementalPhase == IdlePhase) {
return;
}
SliceBudget unlimitedBudget;
PrintPhase("FinishAnyCurrentCollection");
// Use SliceCC because we only want to finish the CC in progress.
Collect(SliceCC, unlimitedBudget, nullptr);
MOZ_ASSERT(mIncrementalPhase == IdlePhase ||
(mIncrementalPhase == ScanAndCollectWhitePhase && mActivelyCollecting),
"FinishAnyCurrentCollection should finish the collection, unless we've reentered the CC during unlinking");
}
// 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 (!mJSRuntime) {
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 && mJSRuntime->UsefulToMergeZones()) {
mMergedInARow++;
return true;
} else {
mMergedInARow = 0;
return false;
}
}
void
nsCycleCollector::BeginCollection(ccType aCCType,
nsICycleCollectorListener* aManualListener)
{
TimeLog timeLog;
MOZ_ASSERT(mIncrementalPhase == IdlePhase);
mCollectionStart = TimeStamp::Now();
if (mJSRuntime) {
mJSRuntime->BeginCycleCollectionCallback();
timeLog.Checkpoint("BeginCycleCollectionCallback()");
}
bool isShutdown = (aCCType == ShutdownCC);
// Set up the listener for this CC.
MOZ_ASSERT_IF(isShutdown, !aManualListener);
MOZ_ASSERT(!mListener, "Forgot to clear a previous listener?");
mListener = aManualListener;
aManualListener = nullptr;
if (!mListener && mParams.LogThisCC(isShutdown)) {
nsRefPtr<nsCycleCollectorLogger> logger = new nsCycleCollectorLogger();
if (mParams.AllTracesThisCC(isShutdown)) {
logger->SetAllTraces();
}
mListener = logger.forget();
}
bool forceGC = isShutdown;
if (!forceGC && mListener) {
// On a WantAllTraces CC, force a synchronous global GC to prevent
// hijinks from ForgetSkippable and compartmental GCs.
mListener->GetWantAllTraces(&forceGC);
}
FixGrayBits(forceGC);
FreeSnowWhite(true);
if (mListener && NS_FAILED(mListener->Begin())) {
mListener = nullptr;
}
// Set up the data structures for building the graph.
mGraph.Init();
mResults.Init();
bool mergeZones = ShouldMergeZones(aCCType);
mResults.mMergedZones = mergeZones;
MOZ_ASSERT(!mBuilder, "Forgot to clear mBuilder");
mBuilder = new CCGraphBuilder(mGraph, mResults, mJSRuntime, mListener,
mergeZones);
if (mJSRuntime) {
mJSRuntime->TraverseRoots(*mBuilder);
timeLog.Checkpoint("mJSRuntime->TraverseRoots()");
}
AutoRestore<bool> ar(mScanInProgress);
MOZ_ASSERT(!mScanInProgress);
mScanInProgress = true;
mPurpleBuf.SelectPointers(*mBuilder);
timeLog.Checkpoint("SelectPointers()");
// We've finished adding roots, and everything in the graph is a root.
mGraph.mRootCount = mGraph.MapCount();
mCurrNode = new NodePool::Enumerator(mGraph.mNodes);
mIncrementalPhase = GraphBuildingPhase;
}
uint32_t
nsCycleCollector::SuspectedCount()
{
CheckThreadSafety();
return mPurpleBuf.Count();
}
void
nsCycleCollector::Shutdown()
{
CheckThreadSafety();
// Always delete snow white objects.
FreeSnowWhite(true);
#ifndef DEBUG
if (PR_GetEnv("MOZ_CC_RUN_DURING_SHUTDOWN"))
#endif
{
ShutdownCollect();
}
}
void
nsCycleCollector::RemoveObjectFromGraph(void* aObj)
{
if (mIncrementalPhase == IdlePhase) {
return;
}
if (PtrInfo* pinfo = mGraph.FindNode(aObj)) {
mGraph.RemoveNodeFromMap(aObj);
pinfo->mPointer = nullptr;
pinfo->mParticipant = nullptr;
}
}
void
nsCycleCollector::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
size_t* aObjectSize,
size_t* aGraphNodesSize,
size_t* aGraphEdgesSize,
size_t* aWeakMapsSize,
size_t* aPurpleBufferSize) const
{
*aObjectSize = aMallocSizeOf(this);
mGraph.SizeOfExcludingThis(aMallocSizeOf, aGraphNodesSize, aGraphEdgesSize,
aWeakMapsSize);
*aPurpleBufferSize = mPurpleBuf.SizeOfExcludingThis(aMallocSizeOf);
// These fields are deliberately not measured:
// - mJSRuntime: 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.
nsRefPtr<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_registerJSRuntime(CycleCollectedJSRuntime* aRt)
{
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 runtime.
MOZ_ASSERT(!data->mRuntime);
data->mRuntime = aRt;
data->mCollector->RegisterJSRuntime(aRt);
}
void
nsCycleCollector_forgetJSRuntime()
{
CollectorData* data = sCollectorData.get();
// We should have started the cycle collector by now.
MOZ_ASSERT(data);
// And we shouldn't have already forgotten our runtime.
MOZ_ASSERT(data->mRuntime);
// But it may have shutdown already.
if (data->mCollector) {
data->mCollector->ForgetJSRuntime();
data->mRuntime = nullptr;
} else {
data->mRuntime = nullptr;
delete data;
sCollectorData.set(nullptr);
}
}
/* static */ CycleCollectedJSRuntime*
CycleCollectedJSRuntime::Get()
{
CollectorData* data = sCollectorData.get();
if (data) {
return data->mRuntime;
}
return nullptr;
}
namespace mozilla {
namespace cyclecollector {
void
HoldJSObjectsImpl(void* aHolder, nsScriptObjectTracer* aTracer)
{
CollectorData* data = sCollectorData.get();
// We should have started the cycle collector by now.
MOZ_ASSERT(data);
MOZ_ASSERT(data->mCollector);
// And we should have a runtime.
MOZ_ASSERT(data->mRuntime);
data->mRuntime->AddJSHolder(aHolder, aTracer);
}
void
HoldJSObjectsImpl(nsISupports* aHolder)
{
nsXPCOMCycleCollectionParticipant* participant;
CallQueryInterface(aHolder, &participant);
MOZ_ASSERT(participant, "Failed to QI to nsXPCOMCycleCollectionParticipant!");
MOZ_ASSERT(participant->CheckForRightISupports(aHolder),
"The result of QIing a JS holder should be the same as ToSupports");
HoldJSObjectsImpl(aHolder, participant);
}
void
DropJSObjectsImpl(void* aHolder)
{
CollectorData* data = sCollectorData.get();
// We should have started the cycle collector by now, and not completely
// shut down.
MOZ_ASSERT(data);
// And we should have a runtime.
MOZ_ASSERT(data->mRuntime);
data->mRuntime->RemoveJSHolder(aHolder);
}
void
DropJSObjectsImpl(nsISupports* aHolder)
{
#ifdef DEBUG
nsXPCOMCycleCollectionParticipant* participant;
CallQueryInterface(aHolder, &participant);
MOZ_ASSERT(participant, "Failed to QI to nsXPCOMCycleCollectionParticipant!");
MOZ_ASSERT(participant->CheckForRightISupports(aHolder),
"The result of QIing a JS holder should be the same as ToSupports");
#endif
DropJSObjectsImpl(static_cast<void*>(aHolder));
}
#ifdef DEBUG
bool
IsJSHolder(void* aHolder)
{
CollectorData* data = sCollectorData.get();
// We should have started the cycle collector by now, and not completely
// shut down.
MOZ_ASSERT(data);
// And we should have a runtime.
MOZ_ASSERT(data->mRuntime);
return data->mRuntime->IsJSHolder(aHolder);
}
#endif
void
DeferredFinalize(nsISupports* aSupports)
{
CollectorData* data = sCollectorData.get();
// We should have started the cycle collector by now, and not completely
// shut down.
MOZ_ASSERT(data);
// And we should have a runtime.
MOZ_ASSERT(data->mRuntime);
data->mRuntime->DeferredFinalize(aSupports);
}
void
DeferredFinalize(DeferredFinalizeAppendFunction aAppendFunc,
DeferredFinalizeFunction aFunc,
void* aThing)
{
CollectorData* data = sCollectorData.get();
// We should have started the cycle collector by now, and not completely
// shut down.
MOZ_ASSERT(data);
// And we should have a runtime.
MOZ_ASSERT(data->mRuntime);
data->mRuntime->DeferredFinalize(aAppendFunc, aFunc, aThing);
}
} // namespace cyclecollector
} // namespace mozilla
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()
{
MOZ_ASSERT(NS_IsMainThread(), "Wrong thread!");
MOZ_ASSERT(!sCollectorData.initialized(), "Called twice!?");
return sCollectorData.init();
}
void
nsCycleCollector_startup()
{
MOZ_ASSERT(sCollectorData.initialized(),
"Forgot to call nsCycleCollector_init!");
if (sCollectorData.get()) {
MOZ_CRASH();
}
CollectorData* data = new CollectorData;
data->mCollector = new nsCycleCollector();
data->mRuntime = 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)
{
CollectorData* data = sCollectorData.get();
if (!data || !data->mRuntime) {
return;
}
data->mRuntime->DispatchDeferredDeletion(aContinuation);
}
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->mRuntime);
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;
data->mCollector->Collect(ManualCC, unlimitedBudget, aManualListener);
}
void
nsCycleCollector_collectSlice(SliceBudget& budget)
{
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);
}
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()
{
CollectorData* data = sCollectorData.get();
if (data) {
MOZ_ASSERT(data->mCollector);
PROFILER_LABEL("nsCycleCollector", "shutdown",
js::ProfileEntry::Category::CC);
data->mCollector->Shutdown();
data->mCollector = nullptr;
if (!data->mRuntime) {
delete data;
sCollectorData.set(nullptr);
}
}
}