https://github.com/mozilla/gecko-dev
Tip revision: 4de65ed647cfede012c65e5b42268b52a3c32ff3 authored by seabld on 31 January 2013, 03:42:17 UTC
Added tag SEAMONKEY_2_16b3_RELEASE for changeset FIREFOX_19_0b4_BUILD1. CLOSED TREE a=release
Added tag SEAMONKEY_2_16b3_RELEASE for changeset FIREFOX_19_0b4_BUILD1. CLOSED TREE a=release
Tip revision: 4de65ed
jscompartment.h
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=4 sw=4 et tw=79:
*
* 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 jscompartment_h___
#define jscompartment_h___
#include "mozilla/Attributes.h"
#include "mozilla/Util.h"
#include "jscntxt.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsobj.h"
#include "jsscope.h"
#include "gc/StoreBuffer.h"
#include "vm/GlobalObject.h"
#include "vm/RegExpObject.h"
namespace js {
namespace ion {
class IonCompartment;
}
struct NativeIterator;
/*
* A single-entry cache for some base-10 double-to-string conversions. This
* helps date-format-xparb.js. It also avoids skewing the results for
* v8-splay.js when measured by the SunSpider harness, where the splay tree
* initialization (which includes many repeated double-to-string conversions)
* is erroneously included in the measurement; see bug 562553.
*/
class DtoaCache {
double d;
int base;
JSFlatString *s; // if s==NULL, d and base are not valid
public:
DtoaCache() : s(NULL) {}
void purge() { s = NULL; }
JSFlatString *lookup(int base, double d) {
return this->s && base == this->base && d == this->d ? this->s : NULL;
}
void cache(int base, double d, JSFlatString *s) {
this->base = base;
this->d = d;
this->s = s;
}
};
/* If HashNumber grows, need to change WrapperHasher. */
JS_STATIC_ASSERT(sizeof(HashNumber) == 4);
struct CrossCompartmentKey
{
enum Kind {
ObjectWrapper,
StringWrapper,
DebuggerScript,
DebuggerObject,
DebuggerEnvironment
};
Kind kind;
JSObject *debugger;
js::gc::Cell *wrapped;
CrossCompartmentKey()
: kind(ObjectWrapper), debugger(NULL), wrapped(NULL) {}
CrossCompartmentKey(JSObject *wrapped)
: kind(ObjectWrapper), debugger(NULL), wrapped(wrapped) {}
CrossCompartmentKey(JSString *wrapped)
: kind(StringWrapper), debugger(NULL), wrapped(wrapped) {}
CrossCompartmentKey(Value wrapped)
: kind(wrapped.isString() ? StringWrapper : ObjectWrapper),
debugger(NULL),
wrapped((js::gc::Cell *)wrapped.toGCThing()) {}
CrossCompartmentKey(const RootedValue &wrapped)
: kind(wrapped.get().isString() ? StringWrapper : ObjectWrapper),
debugger(NULL),
wrapped((js::gc::Cell *)wrapped.get().toGCThing()) {}
CrossCompartmentKey(Kind kind, JSObject *dbg, js::gc::Cell *wrapped)
: kind(kind), debugger(dbg), wrapped(wrapped) {}
};
struct WrapperHasher
{
typedef CrossCompartmentKey Lookup;
static HashNumber hash(const CrossCompartmentKey &key) {
JS_ASSERT(!IsPoisonedPtr(key.wrapped));
return uint32_t(uintptr_t(key.wrapped)) | uint32_t(key.kind);
}
static bool match(const CrossCompartmentKey &l, const CrossCompartmentKey &k) {
return l.kind == k.kind && l.debugger == k.debugger && l.wrapped == k.wrapped;
}
};
typedef HashMap<CrossCompartmentKey, ReadBarrieredValue,
WrapperHasher, SystemAllocPolicy> WrapperMap;
} /* namespace js */
namespace JS {
struct TypeInferenceSizes;
}
namespace js {
class AutoDebugModeGC;
}
struct JSCompartment
{
JSRuntime *rt;
JSPrincipals *principals;
private:
friend struct JSRuntime;
friend struct JSContext;
js::ReadBarriered<js::GlobalObject> global_;
unsigned enterCompartmentDepth;
public:
void enter() { enterCompartmentDepth++; }
void leave() { enterCompartmentDepth--; }
/*
* Nb: global_ might be NULL, if (a) it's the atoms compartment, or (b) the
* compartment's global has been collected. The latter can happen if e.g.
* a string in a compartment is rooted but no object is, and thus the global
* isn't rooted, and thus the global can be finalized while the compartment
* lives on.
*
* In contrast, JSObject::global() is infallible because marking a JSObject
* always marks its global as well.
* TODO: add infallible JSScript::global()
*/
inline js::GlobalObject *maybeGlobal() const;
void initGlobal(js::GlobalObject &global) {
JS_ASSERT(global.compartment() == this);
JS_ASSERT(!global_);
global_ = &global;
}
public:
js::gc::ArenaLists arenas;
#ifdef JSGC_GENERATIONAL
js::gc::Nursery gcNursery;
js::gc::StoreBuffer gcStoreBuffer;
#endif
private:
bool needsBarrier_;
bool ionUsingBarriers_;
public:
bool needsBarrier() const {
return needsBarrier_;
}
bool compileBarriers(bool needsBarrier) const {
return needsBarrier || rt->gcZeal() == js::gc::ZealVerifierPreValue;
}
bool compileBarriers() const {
return compileBarriers(needsBarrier());
}
enum ShouldUpdateIon {
DontUpdateIon,
UpdateIon
};
void setNeedsBarrier(bool needs, ShouldUpdateIon updateIon);
static size_t OffsetOfNeedsBarrier() {
return offsetof(JSCompartment, needsBarrier_);
}
js::GCMarker *barrierTracer() {
JS_ASSERT(needsBarrier_);
return &rt->gcMarker;
}
public:
enum CompartmentGCState {
NoGC,
Mark,
Sweep
};
private:
bool gcScheduled;
CompartmentGCState gcState;
bool gcPreserveCode;
public:
bool isCollecting() const {
if (rt->isHeapCollecting()) {
return gcState != NoGC;
} else {
return needsBarrier();
}
}
bool isPreservingCode() const {
return gcPreserveCode;
}
/*
* If this returns true, all object tracing must be done with a GC marking
* tracer.
*/
bool requireGCTracer() const {
return rt->isHeapCollecting() && gcState != NoGC;
}
void setGCState(CompartmentGCState state) {
JS_ASSERT(rt->isHeapBusy());
gcState = state;
}
void scheduleGC() {
JS_ASSERT(!rt->isHeapBusy());
gcScheduled = true;
}
void unscheduleGC() {
gcScheduled = false;
}
bool isGCScheduled() const {
return gcScheduled;
}
void setPreservingCode(bool preserving) {
gcPreserveCode = preserving;
}
bool wasGCStarted() const {
return gcState != NoGC;
}
bool isGCMarking() {
return gcState == Mark;
}
bool isGCSweeping() {
return gcState == Sweep;
}
size_t gcBytes;
size_t gcTriggerBytes;
size_t gcMaxMallocBytes;
double gcHeapGrowthFactor;
JSCompartment *gcNextCompartment;
bool hold;
bool isSystemCompartment;
int64_t lastCodeRelease;
/* Pools for analysis and type information in this compartment. */
static const size_t LIFO_ALLOC_PRIMARY_CHUNK_SIZE = 32 * 1024;
js::LifoAlloc analysisLifoAlloc;
js::LifoAlloc typeLifoAlloc;
bool activeAnalysis;
bool activeInference;
/* Type information about the scripts and objects in this compartment. */
js::types::TypeCompartment types;
void *data;
bool active; // GC flag, whether there are active frames
js::WrapperMap crossCompartmentWrappers;
/*
* These flags help us to discover if a compartment that shouldn't be alive
* manages to outlive a GC.
*/
bool scheduledForDestruction;
bool maybeAlive;
/* Last time at which an animation was played for a global in this compartment. */
int64_t lastAnimationTime;
js::RegExpCompartment regExps;
private:
void sizeOfTypeInferenceData(JS::TypeInferenceSizes *stats, JSMallocSizeOfFun mallocSizeOf);
public:
void sizeOfIncludingThis(JSMallocSizeOfFun mallocSizeOf, size_t *compartmentObject,
JS::TypeInferenceSizes *tiSizes,
size_t *shapesCompartmentTables, size_t *crossCompartmentWrappers,
size_t *regexpCompartment, size_t *debuggeesSet);
/*
* Shared scope property tree, and arena-pool for allocating its nodes.
*/
js::PropertyTree propertyTree;
/* Set of all unowned base shapes in the compartment. */
js::BaseShapeSet baseShapes;
void sweepBaseShapeTable();
/* Set of initial shapes in the compartment. */
js::InitialShapeSet initialShapes;
void sweepInitialShapeTable();
/* Set of default 'new' or lazy types in the compartment. */
js::types::TypeObjectSet newTypeObjects;
js::types::TypeObjectSet lazyTypeObjects;
void sweepNewTypeObjectTable(js::types::TypeObjectSet &table);
js::types::TypeObject *getNewType(JSContext *cx, js::TaggedProto proto,
JSFunction *fun = NULL, bool isDOM = false);
js::types::TypeObject *getLazyType(JSContext *cx, js::Handle<js::TaggedProto> proto);
/*
* Keeps track of the total number of malloc bytes connected to a
* compartment's GC things. This counter should be used in preference to
* gcMallocBytes. These counters affect collection in the same way as
* gcBytes and gcTriggerBytes.
*/
size_t gcMallocAndFreeBytes;
size_t gcTriggerMallocAndFreeBytes;
/* During GC, stores the index of this compartment in rt->compartments. */
unsigned index;
private:
/*
* Malloc counter to measure memory pressure for GC scheduling. It runs from
* gcMaxMallocBytes down to zero. This counter should be used only when it's
* not possible to know the size of a free.
*/
ptrdiff_t gcMallocBytes;
enum { DebugFromC = 1, DebugFromJS = 2 };
unsigned debugModeBits; // see debugMode() below
public:
JSCompartment(JSRuntime *rt);
~JSCompartment();
bool init(JSContext *cx);
/* Mark cross-compartment wrappers. */
void markCrossCompartmentWrappers(JSTracer *trc);
bool wrap(JSContext *cx, js::Value *vp, JSObject *existing = NULL);
bool wrap(JSContext *cx, JSString **strp);
bool wrap(JSContext *cx, js::HeapPtrString *strp);
bool wrap(JSContext *cx, JSObject **objp, JSObject *existing = NULL);
bool wrapId(JSContext *cx, jsid *idp);
bool wrap(JSContext *cx, js::PropertyOp *op);
bool wrap(JSContext *cx, js::StrictPropertyOp *op);
bool wrap(JSContext *cx, js::PropertyDescriptor *desc);
bool wrap(JSContext *cx, js::AutoIdVector &props);
void mark(JSTracer *trc);
void markTypes(JSTracer *trc);
void discardJitCode(js::FreeOp *fop, bool discardConstraints);
bool isDiscardingJitCode(JSTracer *trc);
void sweep(js::FreeOp *fop, bool releaseTypes);
void sweepCrossCompartmentWrappers();
void purge();
void setGCLastBytes(size_t lastBytes, size_t lastMallocBytes, js::JSGCInvocationKind gckind);
void reduceGCTriggerBytes(size_t amount);
void resetGCMallocBytes();
void setGCMaxMallocBytes(size_t value);
void updateMallocCounter(size_t nbytes) {
ptrdiff_t oldCount = gcMallocBytes;
ptrdiff_t newCount = oldCount - ptrdiff_t(nbytes);
gcMallocBytes = newCount;
if (JS_UNLIKELY(newCount <= 0 && oldCount > 0))
onTooMuchMalloc();
}
bool isTooMuchMalloc() const {
return gcMallocBytes <= 0;
}
void onTooMuchMalloc();
void mallocInCompartment(size_t nbytes) {
gcMallocAndFreeBytes += nbytes;
}
void freeInCompartment(size_t nbytes) {
JS_ASSERT(gcMallocAndFreeBytes >= nbytes);
gcMallocAndFreeBytes -= nbytes;
}
js::DtoaCache dtoaCache;
private:
/*
* Weak reference to each global in this compartment that is a debuggee.
* Each global has its own list of debuggers.
*/
js::GlobalObjectSet debuggees;
private:
JSCompartment *thisForCtor() { return this; }
public:
/*
* There are dueling APIs for debug mode. It can be enabled or disabled via
* JS_SetDebugModeForCompartment. It is automatically enabled and disabled
* by Debugger objects. Therefore debugModeBits has the DebugFromC bit set
* if the C API wants debug mode and the DebugFromJS bit set if debuggees
* is non-empty.
*/
bool debugMode() const { return !!debugModeBits; }
/* True if any scripts from this compartment are on the JS stack. */
bool hasScriptsOnStack();
private:
/* This is called only when debugMode() has just toggled. */
void updateForDebugMode(js::FreeOp *fop, js::AutoDebugModeGC &dmgc);
public:
js::GlobalObjectSet &getDebuggees() { return debuggees; }
bool addDebuggee(JSContext *cx, js::GlobalObject *global);
void removeDebuggee(js::FreeOp *fop, js::GlobalObject *global,
js::GlobalObjectSet::Enum *debuggeesEnum = NULL);
bool setDebugModeFromC(JSContext *cx, bool b, js::AutoDebugModeGC &dmgc);
void clearBreakpointsIn(js::FreeOp *fop, js::Debugger *dbg, JSObject *handler);
void clearTraps(js::FreeOp *fop);
private:
void sweepBreakpoints(js::FreeOp *fop);
public:
js::WatchpointMap *watchpointMap;
js::ScriptCountsMap *scriptCountsMap;
js::DebugScriptMap *debugScriptMap;
/*
* List of potentially active iterators that may need deleted property
* suppression.
*/
js::NativeIterator *enumerators;
#ifdef JS_ION
private:
js::ion::IonCompartment *ionCompartment_;
public:
bool ensureIonCompartmentExists(JSContext *cx);
js::ion::IonCompartment *ionCompartment() {
return ionCompartment_;
}
#endif
};
// For use when changing the debug mode flag on one or more compartments.
// Do not run scripts in any compartment that is scheduled for GC using this
// object. See comment in updateForDebugMode.
//
class js::AutoDebugModeGC
{
JSRuntime *rt;
bool needGC;
public:
explicit AutoDebugModeGC(JSRuntime *rt) : rt(rt), needGC(false) {}
~AutoDebugModeGC() {
// Under some circumstances (say, in the midst of an animation),
// the garbage collector may try to retain JIT code and analyses.
// The DEBUG_MODE_GC reason forces the collector to always throw
// everything away, as required for debug mode transitions.
if (needGC)
GC(rt, GC_NORMAL, gcreason::DEBUG_MODE_GC);
}
void scheduleGC(JSCompartment *compartment) {
JS_ASSERT(!rt->isHeapBusy());
PrepareCompartmentForGC(compartment);
needGC = true;
}
};
inline bool
JSContext::typeInferenceEnabled() const
{
return compartment->types.inferenceEnabled;
}
inline js::Handle<js::GlobalObject*>
JSContext::global() const
{
/*
* It's safe to use |unsafeGet()| here because any compartment that is
* on-stack will be marked automatically, so there's no need for a read
* barrier on it. Once the compartment is popped, the handle is no longer
* safe to use.
*/
return js::Handle<js::GlobalObject*>::fromMarkedLocation(compartment->global_.unsafeGet());
}
namespace js {
class AssertCompartmentUnchanged {
protected:
JSContext * const cx;
JSCompartment * const oldCompartment;
JS_DECL_USE_GUARD_OBJECT_NOTIFIER
public:
AssertCompartmentUnchanged(JSContext *cx JS_GUARD_OBJECT_NOTIFIER_PARAM)
: cx(cx), oldCompartment(cx->compartment) {
JS_GUARD_OBJECT_NOTIFIER_INIT;
}
~AssertCompartmentUnchanged() {
JS_ASSERT(cx->compartment == oldCompartment);
}
};
class AutoCompartment
{
JSContext * const cx_;
JSCompartment * const origin_;
public:
inline AutoCompartment(JSContext *cx, JSObject *target);
inline ~AutoCompartment();
JSContext *context() const { return cx_; }
JSCompartment *origin() const { return origin_; }
private:
AutoCompartment(const AutoCompartment &) MOZ_DELETE;
AutoCompartment & operator=(const AutoCompartment &) MOZ_DELETE;
};
/*
* Entering the atoms comaprtment is not possible with the AutoCompartment
* since the atoms compartment does not have a global.
*
* Note: since most of the VM assumes that cx->global is non-null, only a
* restricted set of (atom creating/destroying) operations may be used from
* inside the atoms compartment.
*/
class AutoEnterAtomsCompartment
{
JSContext *cx;
JSCompartment *oldCompartment;
public:
AutoEnterAtomsCompartment(JSContext *cx)
: cx(cx),
oldCompartment(cx->compartment)
{
cx->setCompartment(cx->runtime->atomsCompartment);
}
~AutoEnterAtomsCompartment()
{
cx->setCompartment(oldCompartment);
}
};
/*
* Use this to change the behavior of an AutoCompartment slightly on error. If
* the exception happens to be an Error object, copy it to the origin compartment
* instead of wrapping it.
*/
class ErrorCopier
{
mozilla::Maybe<AutoCompartment> ∾
RootedObject scope;
public:
ErrorCopier(mozilla::Maybe<AutoCompartment> &ac, JSObject *scope)
: ac(ac), scope(ac.ref().context(), scope) {}
~ErrorCopier();
};
class CompartmentsIter {
private:
JSCompartment **it, **end;
public:
CompartmentsIter(JSRuntime *rt) {
it = rt->compartments.begin();
end = rt->compartments.end();
}
bool done() const { return it == end; }
void next() {
JS_ASSERT(!done());
it++;
}
JSCompartment *get() const {
JS_ASSERT(!done());
return *it;
}
operator JSCompartment *() const { return get(); }
JSCompartment *operator->() const { return get(); }
};
/*
* AutoWrapperVector and AutoWrapperRooter can be used to store wrappers that
* are obtained from the cross-compartment map. However, these classes should
* not be used if the wrapper will escape. For example, it should not be stored
* in the heap.
*
* The AutoWrapper rooters are different from other autorooters because their
* wrappers are marked on every GC slice rather than just the first one. If
* there's some wrapper that we want to use temporarily without causing it to be
* marked, we can use these AutoWrapper classes. If we get unlucky and a GC
* slice runs during the code using the wrapper, the GC will mark the wrapper so
* that it doesn't get swept out from under us. Otherwise, the wrapper needn't
* be marked. This is useful in functions like JS_TransplantObject that
* manipulate wrappers in compartments that may no longer be alive.
*/
/*
* This class stores the data for AutoWrapperVector and AutoWrapperRooter. It
* should not be used in any other situations.
*/
struct WrapperValue
{
/*
* We use unsafeGet() in the constructors to avoid invoking a read barrier
* on the wrapper, which may be dead (see the comment about bug 803376 in
* jsgc.cpp regarding this). If there is an incremental GC while the wrapper
* is in use, the AutoWrapper rooter will ensure the wrapper gets marked.
*/
explicit WrapperValue(const WrapperMap::Ptr &ptr)
: value(*ptr->value.unsafeGet())
{}
explicit WrapperValue(const WrapperMap::Enum &e)
: value(*e.front().value.unsafeGet())
{}
Value &get() { return value; }
Value get() const { return value; }
operator const Value &() const { return value; }
JSObject &toObject() const { return value.toObject(); }
private:
Value value;
};
class AutoWrapperVector : public AutoVectorRooter<WrapperValue>
{
public:
explicit AutoWrapperVector(JSContext *cx
JS_GUARD_OBJECT_NOTIFIER_PARAM)
: AutoVectorRooter<WrapperValue>(cx, WRAPVECTOR)
{
JS_GUARD_OBJECT_NOTIFIER_INIT;
}
JS_DECL_USE_GUARD_OBJECT_NOTIFIER
};
class AutoWrapperRooter : private AutoGCRooter {
public:
AutoWrapperRooter(JSContext *cx, WrapperValue v
JS_GUARD_OBJECT_NOTIFIER_PARAM)
: AutoGCRooter(cx, WRAPPER), value(v)
{
JS_GUARD_OBJECT_NOTIFIER_INIT;
}
operator JSObject *() const {
return value.get().toObjectOrNull();
}
friend void AutoGCRooter::trace(JSTracer *trc);
private:
WrapperValue value;
JS_DECL_USE_GUARD_OBJECT_NOTIFIER
};
} /* namespace js */
#endif /* jscompartment_h___ */