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/* -*- 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/. */
#ifndef gc_AtomMarking_h
#define gc_AtomMarking_h
#include "NamespaceImports.h"
#include "js/Vector.h"
#include "threading/ProtectedData.h"
namespace js {
class AutoLockGC;
class DenseBitmap;
namespace gc {
class Arena;
class GCRuntime;
// This class manages state used for marking atoms during GCs.
// See AtomMarking.cpp for details.
class AtomMarkingRuntime {
// Unused arena atom bitmap indexes. Protected by the GC lock.
js::GCLockData<Vector<size_t, 0, SystemAllocPolicy>> freeArenaIndexes;
inline void markChildren(JSContext* cx, JSAtom*);
inline void markChildren(JSContext* cx, JS::Symbol* symbol);
public:
// The extent of all allocated and free words in atom mark bitmaps.
// This monotonically increases and may be read from without locking.
mozilla::Atomic<size_t, mozilla::SequentiallyConsistent> allocatedWords;
AtomMarkingRuntime() : allocatedWords(0) {}
// Mark an arena as holding things in the atoms zone.
void registerArena(Arena* arena, const AutoLockGC& lock);
// Mark an arena as no longer holding things in the atoms zone.
void unregisterArena(Arena* arena, const AutoLockGC& lock);
// Update the atom marking bitmaps in all collected zones according to the
// atoms zone mark bits.
void refineZoneBitmapsForCollectedZones(GCRuntime* gc, size_t collectedZones);
// Set any bits in the chunk mark bitmaps for atoms which are marked in any
// uncollected zone in the runtime.
void markAtomsUsedByUncollectedZones(GCRuntime* gc, size_t uncollectedZones);
private:
// Fill |bitmap| with an atom marking bitmap based on the things that are
// currently marked in the chunks used by atoms zone arenas. This returns
// false on an allocation failure (but does not report an exception).
bool computeBitmapFromChunkMarkBits(GCRuntime* gc, DenseBitmap& bitmap);
// Update the atom marking bitmap in |zone| according to another
// overapproximation of the reachable atoms in |bitmap|.
void refineZoneBitmapForCollectedZone(Zone* zone, const DenseBitmap& bitmap);
public:
// Mark an atom or id as being newly reachable by the context's zone.
template <typename T>
void markAtom(JSContext* cx, T* thing);
// Version of markAtom that's always inlined, for performance-sensitive
// callers.
template <typename T, bool Fallible>
MOZ_ALWAYS_INLINE bool inlinedMarkAtomInternal(JSContext* cx, T* thing);
template <typename T>
MOZ_ALWAYS_INLINE void inlinedMarkAtom(JSContext* cx, T* thing);
template <typename T>
MOZ_ALWAYS_INLINE bool inlinedMarkAtomFallible(JSContext* cx, T* thing);
void markId(JSContext* cx, jsid id);
void markAtomValue(JSContext* cx, const Value& value);
#ifdef DEBUG
// Return whether |thing/id| is in the atom marking bitmap for |zone|.
template <typename T>
bool atomIsMarked(Zone* zone, T* thing);
bool idIsMarked(Zone* zone, jsid id);
bool valueIsMarked(Zone* zone, const Value& value);
#endif
};
} // namespace gc
} // namespace js
#endif // gc_AtomMarking_h
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