jsgcinlines.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
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*
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* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is SpiderMonkey code.
*
* The Initial Developer of the Original Code is
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* the Initial Developer. All Rights Reserved.
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*
*
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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#ifndef jsgcinlines_h___
#define jsgcinlines_h___
#include "jsgc.h"
#include "jscntxt.h"
#include "jscompartment.h"
#include "jslock.h"
#include "jsscope.h"
#include "jsxml.h"
#include "js/TemplateLib.h"
namespace js {
struct Shape;
namespace gc {
inline JSGCTraceKind
GetGCThingTraceKind(const void *thing)
{
JS_ASSERT(thing);
const Cell *cell = reinterpret_cast<const Cell *>(thing);
return MapAllocToTraceKind(cell->getAllocKind());
}
/* Capacity for slotsToThingKind */
const size_t SLOTS_TO_THING_KIND_LIMIT = 17;
/* Get the best kind to use when making an object with the given slot count. */
static inline AllocKind
GetGCObjectKind(size_t numSlots)
{
extern AllocKind slotsToThingKind[];
if (numSlots >= SLOTS_TO_THING_KIND_LIMIT)
return FINALIZE_OBJECT16;
return slotsToThingKind[numSlots];
}
static inline AllocKind
GetGCObjectKind(Class *clasp)
{
if (clasp == &FunctionClass)
return JSFunction::FinalizeKind;
uint32_t nslots = JSCLASS_RESERVED_SLOTS(clasp);
if (clasp->flags & JSCLASS_HAS_PRIVATE)
nslots++;
return GetGCObjectKind(nslots);
}
/* As for GetGCObjectKind, but for dense array allocation. */
static inline AllocKind
GetGCArrayKind(size_t numSlots)
{
extern AllocKind slotsToThingKind[];
/*
* Dense arrays can use their fixed slots to hold their elements array
* (less two Values worth of ObjectElements header), but if more than the
* maximum number of fixed slots is needed then the fixed slots will be
* unused.
*/
JS_STATIC_ASSERT(ObjectElements::VALUES_PER_HEADER == 2);
if (numSlots > JSObject::NELEMENTS_LIMIT || numSlots + 2 >= SLOTS_TO_THING_KIND_LIMIT)
return FINALIZE_OBJECT2;
return slotsToThingKind[numSlots + 2];
}
static inline AllocKind
GetGCObjectFixedSlotsKind(size_t numFixedSlots)
{
extern AllocKind slotsToThingKind[];
JS_ASSERT(numFixedSlots < SLOTS_TO_THING_KIND_LIMIT);
return slotsToThingKind[numFixedSlots];
}
static inline bool
IsBackgroundAllocKind(AllocKind kind)
{
JS_ASSERT(kind <= FINALIZE_OBJECT_LAST);
return kind % 2 == 1;
}
static inline AllocKind
GetBackgroundAllocKind(AllocKind kind)
{
JS_ASSERT(!IsBackgroundAllocKind(kind));
return (AllocKind) (kind + 1);
}
/*
* Try to get the next larger size for an object, keeping BACKGROUND
* consistent.
*/
static inline bool
TryIncrementAllocKind(AllocKind *kindp)
{
size_t next = size_t(*kindp) + 2;
if (next >= size_t(FINALIZE_OBJECT_LIMIT))
return false;
*kindp = AllocKind(next);
return true;
}
/* Get the number of fixed slots and initial capacity associated with a kind. */
static inline size_t
GetGCKindSlots(AllocKind thingKind)
{
/* Using a switch in hopes that thingKind will usually be a compile-time constant. */
switch (thingKind) {
case FINALIZE_OBJECT0:
case FINALIZE_OBJECT0_BACKGROUND:
return 0;
case FINALIZE_OBJECT2:
case FINALIZE_OBJECT2_BACKGROUND:
return 2;
case FINALIZE_OBJECT4:
case FINALIZE_OBJECT4_BACKGROUND:
return 4;
case FINALIZE_OBJECT8:
case FINALIZE_OBJECT8_BACKGROUND:
return 8;
case FINALIZE_OBJECT12:
case FINALIZE_OBJECT12_BACKGROUND:
return 12;
case FINALIZE_OBJECT16:
case FINALIZE_OBJECT16_BACKGROUND:
return 16;
default:
JS_NOT_REACHED("Bad object finalize kind");
return 0;
}
}
static inline size_t
GetGCKindSlots(AllocKind thingKind, Class *clasp)
{
size_t nslots = GetGCKindSlots(thingKind);
/* An object's private data uses the space taken by its last fixed slot. */
if (clasp->flags & JSCLASS_HAS_PRIVATE) {
JS_ASSERT(nslots > 0);
nslots--;
}
/*
* Functions have a larger finalize kind than FINALIZE_OBJECT to reserve
* space for the extra fields in JSFunction, but have no fixed slots.
*/
if (clasp == &FunctionClass)
nslots = 0;
return nslots;
}
static inline void
GCPoke(JSContext *cx, Value oldval)
{
/*
* Since we're forcing a GC from JS_GC anyway, don't bother wasting cycles
* loading oldval. XXX remove implied force, fix jsinterp.c's "second arg
* ignored", etc.
*/
#if 1
cx->runtime->gcPoke = JS_TRUE;
#else
cx->runtime->gcPoke = oldval.isGCThing();
#endif
#ifdef JS_GC_ZEAL
/* Schedule a GC to happen "soon" after a GC poke. */
if (cx->runtime->gcZeal() >= js::gc::ZealPokeThreshold)
cx->runtime->gcNextScheduled = 1;
#endif
}
/*
* Invoke ArenaOp and CellOp on every arena and cell in a compartment which
* have the specified thing kind.
*/
template <class ArenaOp, class CellOp>
void
ForEachArenaAndCell(JSCompartment *compartment, AllocKind thingKind,
ArenaOp arenaOp, CellOp cellOp)
{
size_t thingSize = Arena::thingSize(thingKind);
ArenaHeader *aheader = compartment->arenas.getFirstArena(thingKind);
for (; aheader; aheader = aheader->next) {
Arena *arena = aheader->getArena();
arenaOp(arena);
FreeSpan firstSpan(aheader->getFirstFreeSpan());
const FreeSpan *span = &firstSpan;
for (uintptr_t thing = arena->thingsStart(thingKind); ; thing += thingSize) {
JS_ASSERT(thing <= arena->thingsEnd());
if (thing == span->first) {
if (!span->hasNext())
break;
thing = span->last;
span = span->nextSpan();
} else {
Cell *t = reinterpret_cast<Cell *>(thing);
cellOp(t);
}
}
}
}
class CellIterImpl
{
size_t firstThingOffset;
size_t thingSize;
ArenaHeader *aheader;
FreeSpan firstSpan;
const FreeSpan *span;
uintptr_t thing;
Cell *cell;
protected:
CellIterImpl() {
}
void init(JSCompartment *comp, AllocKind kind) {
JS_ASSERT(comp->arenas.isSynchronizedFreeList(kind));
firstThingOffset = Arena::firstThingOffset(kind);
thingSize = Arena::thingSize(kind);
aheader = comp->arenas.getFirstArena(kind);
firstSpan.initAsEmpty();
span = &firstSpan;
thing = span->first;
next();
}
public:
bool done() const {
return !cell;
}
template<typename T> T *get() const {
JS_ASSERT(!done());
return static_cast<T *>(cell);
}
Cell *getCell() const {
JS_ASSERT(!done());
return cell;
}
void next() {
for (;;) {
if (thing != span->first)
break;
if (JS_LIKELY(span->hasNext())) {
thing = span->last + thingSize;
span = span->nextSpan();
break;
}
if (!aheader) {
cell = NULL;
return;
}
firstSpan = aheader->getFirstFreeSpan();
span = &firstSpan;
thing = aheader->arenaAddress() | firstThingOffset;
aheader = aheader->next;
}
cell = reinterpret_cast<Cell *>(thing);
thing += thingSize;
}
};
class CellIterUnderGC : public CellIterImpl {
public:
CellIterUnderGC(JSCompartment *comp, AllocKind kind) {
JS_ASSERT(comp->rt->gcRunning);
init(comp, kind);
}
};
/*
* When using the iterator outside the GC the caller must ensure that no GC or
* allocations of GC things are possible and that the background finalization
* for the given thing kind is not enabled or is done.
*/
class CellIter: public CellIterImpl
{
ArenaLists *lists;
AllocKind kind;
#ifdef DEBUG
size_t *counter;
#endif
public:
CellIter(JSContext *cx, JSCompartment *comp, AllocKind kind)
: lists(&comp->arenas),
kind(kind) {
#ifdef JS_THREADSAFE
JS_ASSERT(comp->arenas.doneBackgroundFinalize(kind));
#endif
if (lists->isSynchronizedFreeList(kind)) {
lists = NULL;
} else {
JS_ASSERT(!comp->rt->gcRunning);
lists->copyFreeListToArena(kind);
}
#ifdef DEBUG
counter = &cx->runtime->noGCOrAllocationCheck;
++*counter;
#endif
init(comp, kind);
}
~CellIter() {
#ifdef DEBUG
JS_ASSERT(*counter > 0);
--*counter;
#endif
if (lists)
lists->clearFreeListInArena(kind);
}
};
/* Signatures for ArenaOp and CellOp above. */
inline void EmptyArenaOp(Arena *arena) {}
inline void EmptyCellOp(Cell *t) {}
/*
* Allocates a new GC thing. After a successful allocation the caller must
* fully initialize the thing before calling any function that can potentially
* trigger GC. This will ensure that GC tracing never sees junk values stored
* in the partially initialized thing.
*/
template <typename T>
inline T *
NewGCThing(JSContext *cx, js::gc::AllocKind kind, size_t thingSize)
{
JS_ASSERT(thingSize == js::gc::Arena::thingSize(kind));
#ifdef JS_THREADSAFE
JS_ASSERT_IF((cx->compartment == cx->runtime->atomsCompartment),
kind == js::gc::FINALIZE_STRING || kind == js::gc::FINALIZE_SHORT_STRING);
#endif
JS_ASSERT(!cx->runtime->gcRunning);
JS_ASSERT(!cx->runtime->noGCOrAllocationCheck);
#ifdef JS_GC_ZEAL
if (cx->runtime->needZealousGC())
js::gc::RunDebugGC(cx);
#endif
js::gc::MaybeCheckStackRoots(cx);
JSCompartment *comp = cx->compartment;
void *t = comp->arenas.allocateFromFreeList(kind, thingSize);
if (!t)
t = js::gc::ArenaLists::refillFreeList(cx, kind);
return static_cast<T *>(t);
}
/* Alternate form which allocates a GC thing if doing so cannot trigger a GC. */
template <typename T>
inline T *
TryNewGCThing(JSContext *cx, js::gc::AllocKind kind, size_t thingSize)
{
JS_ASSERT(thingSize == js::gc::Arena::thingSize(kind));
#ifdef JS_THREADSAFE
JS_ASSERT_IF((cx->compartment == cx->runtime->atomsCompartment),
kind == js::gc::FINALIZE_STRING || kind == js::gc::FINALIZE_SHORT_STRING);
#endif
JS_ASSERT(!cx->runtime->gcRunning);
JS_ASSERT(!cx->runtime->noGCOrAllocationCheck);
#ifdef JS_GC_ZEAL
if (cx->runtime->needZealousGC())
return NULL;
#endif
void *t = cx->compartment->arenas.allocateFromFreeList(kind, thingSize);
return static_cast<T *>(t);
}
} /* namespace gc */
} /* namespace js */
inline JSObject *
js_NewGCObject(JSContext *cx, js::gc::AllocKind kind)
{
JS_ASSERT(kind >= js::gc::FINALIZE_OBJECT0 && kind <= js::gc::FINALIZE_OBJECT_LAST);
return js::gc::NewGCThing<JSObject>(cx, kind, js::gc::Arena::thingSize(kind));
}
inline JSObject *
js_TryNewGCObject(JSContext *cx, js::gc::AllocKind kind)
{
JS_ASSERT(kind >= js::gc::FINALIZE_OBJECT0 && kind <= js::gc::FINALIZE_OBJECT_LAST);
return js::gc::TryNewGCThing<JSObject>(cx, kind, js::gc::Arena::thingSize(kind));
}
inline JSString *
js_NewGCString(JSContext *cx)
{
return js::gc::NewGCThing<JSString>(cx, js::gc::FINALIZE_STRING, sizeof(JSString));
}
inline JSShortString *
js_NewGCShortString(JSContext *cx)
{
return js::gc::NewGCThing<JSShortString>(cx, js::gc::FINALIZE_SHORT_STRING, sizeof(JSShortString));
}
inline JSExternalString *
js_NewGCExternalString(JSContext *cx)
{
return js::gc::NewGCThing<JSExternalString>(cx, js::gc::FINALIZE_EXTERNAL_STRING,
sizeof(JSExternalString));
}
inline JSScript *
js_NewGCScript(JSContext *cx)
{
return js::gc::NewGCThing<JSScript>(cx, js::gc::FINALIZE_SCRIPT, sizeof(JSScript));
}
inline js::Shape *
js_NewGCShape(JSContext *cx)
{
return js::gc::NewGCThing<js::Shape>(cx, js::gc::FINALIZE_SHAPE, sizeof(js::Shape));
}
inline js::BaseShape *
js_NewGCBaseShape(JSContext *cx)
{
return js::gc::NewGCThing<js::BaseShape>(cx, js::gc::FINALIZE_BASE_SHAPE, sizeof(js::BaseShape));
}
#if JS_HAS_XML_SUPPORT
extern JSXML *
js_NewGCXML(JSContext *cx);
#endif
#endif /* jsgcinlines_h___ */
