gecko-dev/js/public/GCAPI.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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 js_GCAPI_h
#define js_GCAPI_h
#include "js/HeapAPI.h"
namespace JS {
#define GCREASONS(D) \
/* Reasons internal to the JS engine */ \
D(API) \
D(MAYBEGC) \
D(LAST_CONTEXT) \
D(DESTROY_CONTEXT) \
D(LAST_DITCH) \
D(TOO_MUCH_MALLOC) \
D(ALLOC_TRIGGER) \
D(DEBUG_GC) \
D(DEBUG_MODE_GC) \
D(TRANSPLANT) \
D(RESET) \
D(OUT_OF_NURSERY) \
D(EVICT_NURSERY) \
D(FULL_STORE_BUFFER) \
\
/* These are reserved for future use. */ \
D(RESERVED0) \
D(RESERVED1) \
D(RESERVED2) \
D(RESERVED3) \
D(RESERVED4) \
D(RESERVED5) \
D(RESERVED6) \
D(RESERVED7) \
D(RESERVED8) \
D(RESERVED9) \
D(RESERVED10) \
D(RESERVED11) \
D(RESERVED12) \
D(RESERVED13) \
D(RESERVED14) \
D(RESERVED15) \
D(RESERVED16) \
D(RESERVED17) \
D(RESERVED18) \
D(RESERVED19) \
\
/* Reasons from Firefox */ \
D(DOM_WINDOW_UTILS) \
D(COMPONENT_UTILS) \
D(MEM_PRESSURE) \
D(CC_WAITING) \
D(CC_FORCED) \
D(LOAD_END) \
D(POST_COMPARTMENT) \
D(PAGE_HIDE) \
D(NSJSCONTEXT_DESTROY) \
D(SET_NEW_DOCUMENT) \
D(SET_DOC_SHELL) \
D(DOM_UTILS) \
D(DOM_IPC) \
D(DOM_WORKER) \
D(INTER_SLICE_GC) \
D(REFRESH_FRAME) \
D(FULL_GC_TIMER) \
D(SHUTDOWN_CC) \
D(FINISH_LARGE_EVALUTE)
namespace gcreason {
/* GCReasons will end up looking like JSGC_MAYBEGC */
enum Reason {
#define MAKE_REASON(name) name,
GCREASONS(MAKE_REASON)
#undef MAKE_REASON
NO_REASON,
NUM_REASONS,
/*
* For telemetry, we want to keep a fixed max bucket size over time so we
* don't have to switch histograms. 100 is conservative; as of this writing
* there are 26. But the cost of extra buckets seems to be low while the
* cost of switching histograms is high.
*/
NUM_TELEMETRY_REASONS = 100
};
} /* namespace gcreason */
extern JS_FRIEND_API(void)
PrepareZoneForGC(Zone *zone);
extern JS_FRIEND_API(void)
PrepareForFullGC(JSRuntime *rt);
extern JS_FRIEND_API(void)
PrepareForIncrementalGC(JSRuntime *rt);
extern JS_FRIEND_API(bool)
IsGCScheduled(JSRuntime *rt);
extern JS_FRIEND_API(void)
SkipZoneForGC(Zone *zone);
/*
* When triggering a GC using one of the functions below, it is first necessary
* to select the compartments to be collected. To do this, you can call
* PrepareZoneForGC on each compartment, or you can call PrepareForFullGC
* to select all compartments. Failing to select any compartment is an error.
*/
extern JS_FRIEND_API(void)
GCForReason(JSRuntime *rt, gcreason::Reason reason);
extern JS_FRIEND_API(void)
ShrinkingGC(JSRuntime *rt, gcreason::Reason reason);
extern JS_FRIEND_API(void)
ShrinkGCBuffers(JSRuntime *rt);
extern JS_FRIEND_API(void)
IncrementalGC(JSRuntime *rt, gcreason::Reason reason, int64_t millis = 0);
extern JS_FRIEND_API(void)
FinishIncrementalGC(JSRuntime *rt, gcreason::Reason reason);
enum GCProgress {
/*
* During non-incremental GC, the GC is bracketed by JSGC_CYCLE_BEGIN/END
* callbacks. During an incremental GC, the sequence of callbacks is as
* follows:
* JSGC_CYCLE_BEGIN, JSGC_SLICE_END (first slice)
* JSGC_SLICE_BEGIN, JSGC_SLICE_END (second slice)
* ...
* JSGC_SLICE_BEGIN, JSGC_CYCLE_END (last slice)
*/
GC_CYCLE_BEGIN,
GC_SLICE_BEGIN,
GC_SLICE_END,
GC_CYCLE_END
};
struct JS_FRIEND_API(GCDescription) {
bool isCompartment_;
GCDescription(bool isCompartment)
: isCompartment_(isCompartment) {}
jschar *formatMessage(JSRuntime *rt) const;
jschar *formatJSON(JSRuntime *rt, uint64_t timestamp) const;
};
typedef void
(* GCSliceCallback)(JSRuntime *rt, GCProgress progress, const GCDescription &desc);
extern JS_FRIEND_API(GCSliceCallback)
SetGCSliceCallback(JSRuntime *rt, GCSliceCallback callback);
/*
* Signals a good place to do an incremental slice, because the browser is
* drawing a frame.
*/
extern JS_FRIEND_API(void)
NotifyDidPaint(JSRuntime *rt);
extern JS_FRIEND_API(bool)
IsIncrementalGCEnabled(JSRuntime *rt);
JS_FRIEND_API(bool)
IsIncrementalGCInProgress(JSRuntime *rt);
extern JS_FRIEND_API(void)
DisableIncrementalGC(JSRuntime *rt);
extern JS_FRIEND_API(void)
DisableGenerationalGC(JSRuntime *rt);
extern JS_FRIEND_API(bool)
IsIncrementalBarrierNeeded(JSRuntime *rt);
extern JS_FRIEND_API(bool)
IsIncrementalBarrierNeeded(JSContext *cx);
extern JS_FRIEND_API(void)
IncrementalReferenceBarrier(void *ptr, JSGCTraceKind kind);
extern JS_FRIEND_API(void)
IncrementalValueBarrier(const Value &v);
extern JS_FRIEND_API(void)
IncrementalObjectBarrier(JSObject *obj);
extern JS_FRIEND_API(void)
PokeGC(JSRuntime *rt);
/* Was the most recent GC run incrementally? */
extern JS_FRIEND_API(bool)
WasIncrementalGC(JSRuntime *rt);
class ObjectPtr
{
Heap<JSObject *> value;
public:
ObjectPtr() : value(NULL) {}
ObjectPtr(JSObject *obj) : value(obj) {}
/* Always call finalize before the destructor. */
~ObjectPtr() { JS_ASSERT(!value); }
void finalize(JSRuntime *rt) {
if (IsIncrementalBarrierNeeded(rt))
IncrementalObjectBarrier(value);
value = NULL;
}
void init(JSObject *obj) { value = obj; }
JSObject *get() const { return value; }
void writeBarrierPre(JSRuntime *rt) {
IncrementalObjectBarrier(value);
}
bool isAboutToBeFinalized() {
return JS_IsAboutToBeFinalized(&value);
}
ObjectPtr &operator=(JSObject *obj) {
IncrementalObjectBarrier(value);
value = obj;
return *this;
}
void trace(JSTracer *trc, const char *name) {
JS_CallHeapObjectTracer(trc, &value, name);
}
JSObject &operator*() const { return *value; }
JSObject *operator->() const { return value; }
operator JSObject *() const { return value; }
};
/*
* Unsets the gray bit for anything reachable from |thing|. |kind| should not be
* JSTRACE_SHAPE. |thing| should be non-null.
*/
extern JS_FRIEND_API(void)
UnmarkGrayGCThingRecursively(void *thing, JSGCTraceKind kind);
/*
* This should be called when an object that is marked gray is exposed to the JS
* engine (by handing it to running JS code or writing it into live JS
* data). During incremental GC, since the gray bits haven't been computed yet,
* we conservatively mark the object black.
*/
static JS_ALWAYS_INLINE void
ExposeGCThingToActiveJS(void *thing, JSGCTraceKind kind)
{
JS_ASSERT(kind != JSTRACE_SHAPE);
shadow::Runtime *rt = js::gc::GetGCThingRuntime(thing);
#ifdef JSGC_GENERATIONAL
/*
* GC things residing in the nursery cannot be gray: they have no mark bits.
* All live objects in the nursery are moved to tenured at the beginning of
* each GC slice, so the gray marker never sees nursery things.
*/
if (uintptr_t(thing) >= rt->gcNurseryStart_ && uintptr_t(thing) < rt->gcNurseryEnd_)
return;
#endif
if (IsIncrementalBarrierNeededOnGCThing(rt, thing, kind))
IncrementalReferenceBarrier(thing, kind);
else if (GCThingIsMarkedGray(thing))
UnmarkGrayGCThingRecursively(thing, kind);
}
static JS_ALWAYS_INLINE void
ExposeValueToActiveJS(const Value &v)
{
if (v.isMarkable())
ExposeGCThingToActiveJS(v.toGCThing(), v.gcKind());
}
} /* namespace JS */
#endif /* js_GCAPI_h */