jspubtd.h
/* -*- 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 jspubtd_h
#define jspubtd_h
/*
* JS public API typedefs.
*/
#include "mozilla/Assertions.h"
#include "mozilla/EnumeratedArray.h"
#include "mozilla/LinkedList.h"
#include "mozilla/PodOperations.h"
#include "jsprototypes.h"
#include "jstypes.h"
#include "js/TraceKind.h"
#include "js/TypeDecls.h"
#if defined(JS_GC_ZEAL) || defined(DEBUG)
# define JSGC_HASH_TABLE_CHECKS
#endif
namespace JS {
template <typename T>
class AutoVectorRooter;
typedef AutoVectorRooter<jsid> AutoIdVector;
class CallArgs;
template <typename T>
class Rooted;
class JS_FRIEND_API(CompileOptions);
class JS_FRIEND_API(ReadOnlyCompileOptions);
class JS_FRIEND_API(OwningCompileOptions);
class JS_FRIEND_API(TransitiveCompileOptions);
class JS_PUBLIC_API(CompartmentOptions);
class Value;
struct Zone;
} /* namespace JS */
namespace js {
struct ContextFriendFields;
class RootLists;
} // namespace js
/*
* Run-time version enumeration. For compile-time version checking, please use
* the JS_HAS_* macros in jsversion.h, or use MOZJS_MAJOR_VERSION,
* MOZJS_MINOR_VERSION, MOZJS_PATCH_VERSION, and MOZJS_ALPHA definitions.
*/
enum JSVersion {
JSVERSION_ECMA_3 = 148,
JSVERSION_1_6 = 160,
JSVERSION_1_7 = 170,
JSVERSION_1_8 = 180,
JSVERSION_ECMA_5 = 185,
JSVERSION_DEFAULT = 0,
JSVERSION_UNKNOWN = -1,
JSVERSION_LATEST = JSVERSION_ECMA_5
};
/* Result of typeof operator enumeration. */
enum JSType {
JSTYPE_VOID, /* undefined */
JSTYPE_OBJECT, /* object */
JSTYPE_FUNCTION, /* function */
JSTYPE_STRING, /* string */
JSTYPE_NUMBER, /* number */
JSTYPE_BOOLEAN, /* boolean */
JSTYPE_NULL, /* null */
JSTYPE_SYMBOL, /* symbol */
JSTYPE_LIMIT
};
/* Dense index into cached prototypes and class atoms for standard objects. */
enum JSProtoKey {
#define PROTOKEY_AND_INITIALIZER(name,code,init,clasp) JSProto_##name = code,
JS_FOR_EACH_PROTOTYPE(PROTOKEY_AND_INITIALIZER)
#undef PROTOKEY_AND_INITIALIZER
JSProto_LIMIT
};
/* Struct forward declarations. */
struct JSClass;
struct JSCompartment;
struct JSCrossCompartmentCall;
class JSErrorReport;
struct JSExceptionState;
struct JSFunctionSpec;
struct JSLocaleCallbacks;
struct JSObjectMap;
struct JSPrincipals;
struct JSPropertyName;
struct JSPropertySpec;
struct JSRuntime;
struct JSSecurityCallbacks;
struct JSStructuredCloneCallbacks;
struct JSStructuredCloneReader;
struct JSStructuredCloneWriter;
class JS_PUBLIC_API(JSTracer);
class JSFlatString;
typedef struct PRCallOnceType JSCallOnceType;
typedef bool (*JSInitCallback)(void);
template<typename T> struct JSConstScalarSpec;
typedef JSConstScalarSpec<double> JSConstDoubleSpec;
typedef JSConstScalarSpec<int32_t> JSConstIntegerSpec;
/*
* Generic trace operation that calls JS_CallTracer on each traceable thing
* stored in data.
*/
typedef void
(* JSTraceDataOp)(JSTracer* trc, void* data);
namespace js {
namespace gc {
class AutoTraceSession;
class StoreBuffer;
} // namespace gc
} // namespace js
namespace JS {
struct PropertyDescriptor;
typedef void (*OffThreadCompileCallback)(void* token, void* callbackData);
enum class HeapState {
Idle, // doing nothing with the GC heap
Tracing, // tracing the GC heap without collecting, e.g. IterateCompartments()
MajorCollecting, // doing a GC of the major heap
MinorCollecting // doing a GC of the minor heap (nursery)
};
namespace shadow {
struct Runtime
{
protected:
// Allow inlining of heapState checks.
friend class js::gc::AutoTraceSession;
JS::HeapState heapState_;
js::gc::StoreBuffer* gcStoreBufferPtr_;
public:
Runtime()
: heapState_(JS::HeapState::Idle)
, gcStoreBufferPtr_(nullptr)
{}
bool isHeapBusy() const { return heapState_ != JS::HeapState::Idle; }
bool isHeapMajorCollecting() const { return heapState_ == JS::HeapState::MajorCollecting; }
bool isHeapMinorCollecting() const { return heapState_ == JS::HeapState::MinorCollecting; }
bool isHeapCollecting() const { return isHeapMinorCollecting() || isHeapMajorCollecting(); }
js::gc::StoreBuffer* gcStoreBufferPtr() { return gcStoreBufferPtr_; }
static JS::shadow::Runtime* asShadowRuntime(JSRuntime* rt) {
return reinterpret_cast<JS::shadow::Runtime*>(rt);
}
protected:
void setGCStoreBufferPtr(js::gc::StoreBuffer* storeBuffer) {
gcStoreBufferPtr_ = storeBuffer;
}
};
} /* namespace shadow */
class JS_PUBLIC_API(AutoGCRooter)
{
public:
AutoGCRooter(JSContext* cx, ptrdiff_t tag);
AutoGCRooter(js::ContextFriendFields* cx, ptrdiff_t tag);
~AutoGCRooter() {
MOZ_ASSERT(this == *stackTop);
*stackTop = down;
}
/* Implemented in gc/RootMarking.cpp. */
inline void trace(JSTracer* trc);
static void traceAll(JSTracer* trc);
static void traceAllWrappers(JSTracer* trc);
/* T must be a context type */
template<typename T>
static void traceAllInContext(T* cx, JSTracer* trc) {
for (AutoGCRooter* gcr = cx->roots.autoGCRooters_; gcr; gcr = gcr->down)
gcr->trace(trc);
}
protected:
AutoGCRooter * const down;
/*
* Discriminates actual subclass of this being used. If non-negative, the
* subclass roots an array of values of the length stored in this field.
* If negative, meaning is indicated by the corresponding value in the enum
* below. Any other negative value indicates some deeper problem such as
* memory corruption.
*/
ptrdiff_t tag_;
enum {
VALARRAY = -2, /* js::AutoValueArray */
PARSER = -3, /* js::frontend::Parser */
VALVECTOR = -10, /* js::AutoValueVector */
IDVECTOR = -11, /* js::AutoIdVector */
OBJVECTOR = -14, /* js::AutoObjectVector */
IONMASM = -19, /* js::jit::MacroAssembler */
WRAPVECTOR = -20, /* js::AutoWrapperVector */
WRAPPER = -21, /* js::AutoWrapperRooter */
CUSTOM = -26 /* js::CustomAutoRooter */
};
static ptrdiff_t GetTag(const Value& value) { return VALVECTOR; }
static ptrdiff_t GetTag(const jsid& id) { return IDVECTOR; }
static ptrdiff_t GetTag(JSObject* obj) { return OBJVECTOR; }
private:
AutoGCRooter ** const stackTop;
/* No copy or assignment semantics. */
AutoGCRooter(AutoGCRooter& ida) = delete;
void operator=(AutoGCRooter& ida) = delete;
};
// Our instantiations of Rooted<void*> and PersistentRooted<void*> require an
// instantiation of MapTypeToRootKind.
template <>
struct MapTypeToRootKind<void*> {
static const RootKind kind = RootKind::Traceable;
};
} /* namespace JS */
namespace js {
class ExclusiveContext;
/*
* This list enumerates the different types of conceptual stacks we have in
* SpiderMonkey. In reality, they all share the C stack, but we allow different
* stack limits depending on the type of code running.
*/
enum StackKind
{
StackForSystemCode, // C++, such as the GC, running on behalf of the VM.
StackForTrustedScript, // Script running with trusted principals.
StackForUntrustedScript, // Script running with untrusted principals.
StackKindCount
};
// Abstracts JS rooting mechanisms so they can be shared between the JSContext
// and JSRuntime.
class RootLists
{
// Stack GC roots for Rooted GC heap pointers.
mozilla::EnumeratedArray<JS::RootKind, JS::RootKind::Limit, JS::Rooted<void*>*> stackRoots_;
template <typename T> friend class JS::Rooted;
// Stack GC roots for AutoFooRooter classes.
JS::AutoGCRooter* autoGCRooters_;
friend class JS::AutoGCRooter;
// Heap GC roots for PersistentRooted pointers.
mozilla::EnumeratedArray<JS::RootKind, JS::RootKind::Limit,
mozilla::LinkedList<JS::PersistentRooted<void*>>> heapRoots_;
template <typename T> friend class JS::PersistentRooted;
public:
RootLists() : autoGCRooters_(nullptr) {
for (auto& stackRootPtr : stackRoots_) {
stackRootPtr = nullptr;
}
}
~RootLists() {
// The semantics of PersistentRooted containing pointers and tagged
// pointers are somewhat different from those of PersistentRooted
// containing a structure with a trace method. PersistentRooted
// containing pointers are allowed to outlive the owning RootLists,
// whereas those containing a traceable structure are not.
//
// The purpose of this feature is to support lazy initialization of
// global references for the several places in Gecko that do not have
// access to a tighter context, but that still need to refer to GC
// pointers. For such pointers, FinishPersistentRootedChains ensures
// that the contained references are nulled out when the owning
// RootLists dies to prevent UAF errors.
//
// However, for RootKind::Traceable, we do not know the concrete type
// of the held thing, so we simply cannot do this without accruing
// extra overhead and complexity for all users for a case that is
// unlikely to ever be used in practice. For this reason, the following
// assertion disallows usage of PersistentRooted<Traceable> that
// outlives the RootLists.
MOZ_ASSERT(heapRoots_[JS::RootKind::Traceable].isEmpty());
}
void traceStackRoots(JSTracer* trc);
void checkNoGCRooters();
void tracePersistentRoots(JSTracer* trc);
void finishPersistentRoots();
};
struct ContextFriendFields
{
protected:
JSRuntime* const runtime_;
/* The current compartment. */
JSCompartment* compartment_;
/* The current zone. */
JS::Zone* zone_;
public:
/* Rooting structures. */
RootLists roots;
explicit ContextFriendFields(JSRuntime* rt)
: runtime_(rt), compartment_(nullptr), zone_(nullptr)
{}
static const ContextFriendFields* get(const JSContext* cx) {
return reinterpret_cast<const ContextFriendFields*>(cx);
}
static ContextFriendFields* get(JSContext* cx) {
return reinterpret_cast<ContextFriendFields*>(cx);
}
friend JSRuntime* GetRuntime(const JSContext* cx);
friend JSCompartment* GetContextCompartment(const JSContext* cx);
friend JS::Zone* GetContextZone(const JSContext* cx);
template <typename T> friend class JS::Rooted;
};
/*
* Inlinable accessors for JSContext.
*
* - These must not be available on the more restricted superclasses of
* JSContext, so we can't simply define them on ContextFriendFields.
*
* - They're perfectly ordinary JSContext functionality, so ought to be
* usable without resorting to jsfriendapi.h, and when JSContext is an
* incomplete type.
*/
inline JSRuntime*
GetRuntime(const JSContext* cx)
{
return ContextFriendFields::get(cx)->runtime_;
}
inline JSCompartment*
GetContextCompartment(const JSContext* cx)
{
return ContextFriendFields::get(cx)->compartment_;
}
inline JS::Zone*
GetContextZone(const JSContext* cx)
{
return ContextFriendFields::get(cx)->zone_;
}
class PerThreadData;
struct PerThreadDataFriendFields
{
private:
// Note: this type only exists to permit us to derive the offset of
// the perThread data within the real JSRuntime* type in a portable
// way.
struct RuntimeDummy : JS::shadow::Runtime
{
struct PerThreadDummy {
void* field1;
uintptr_t field2;
#ifdef JS_DEBUG
uint64_t field3;
#endif
} mainThread;
};
public:
/* Rooting structures. */
RootLists roots;
PerThreadDataFriendFields();
/* Limit pointer for checking native stack consumption. */
uintptr_t nativeStackLimit[js::StackKindCount];
static const size_t RuntimeMainThreadOffset = offsetof(RuntimeDummy, mainThread);
static inline PerThreadDataFriendFields* get(js::PerThreadData* pt) {
return reinterpret_cast<PerThreadDataFriendFields*>(pt);
}
static inline PerThreadDataFriendFields* getMainThread(JSRuntime* rt) {
// mainThread must always appear directly after |JS::shadow::Runtime|.
// Tested by a JS_STATIC_ASSERT in |jsfriendapi.cpp|
return reinterpret_cast<PerThreadDataFriendFields*>(
reinterpret_cast<char*>(rt) + RuntimeMainThreadOffset);
}
static inline const PerThreadDataFriendFields* getMainThread(const JSRuntime* rt) {
// mainThread must always appear directly after |JS::shadow::Runtime|.
// Tested by a JS_STATIC_ASSERT in |jsfriendapi.cpp|
return reinterpret_cast<const PerThreadDataFriendFields*>(
reinterpret_cast<const char*>(rt) + RuntimeMainThreadOffset);
}
template <typename T> friend class JS::Rooted;
};
} /* namespace js */
#endif /* jspubtd_h */
