The Tor Browser: comparison js/src/gc/Marking.h

--1:000000000000
+:53a9bb6f442e
+/* -*- 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 gc_Marking_h
+#define gc_Marking_h
+#include "gc/Barrier.h"
+class JSAtom;
+class JSLinearString;
+namespace js {
+class ArgumentsObject;
+class ArrayBufferObject;
+class ArrayBufferViewObject;
+class SharedArrayBufferObject;
+class BaseShape;
+class DebugScopeObject;
+struct GCMarker;
+class GlobalObject;
+class LazyScript;
+class ScopeObject;
+class Shape;
+class UnownedBaseShape;
+template<class, typename> class HeapPtr;
+namespace jit {
+class JitCode;
+class IonScript;
+class VMFunction;
+}
+namespace types {
+class Type;
+}
+namespace gc {
+/*** Object Marking ***/
+/*
+* These functions expose marking functionality for all of the different GC
+* thing kinds. For each GC thing, there are several variants. As an example,
+* these are the variants generated for JSObject. They are listed from most to
+* least desirable for use:
+*
+* MarkObject(JSTracer *trc, const HeapPtr<JSObject> &thing, const char *name);
+*     This function should be used for marking JSObjects, in preference to all
+*     others below. Use it when you have HeapPtr<JSObject>, which
+*     automatically implements write barriers.
+*
+* MarkObjectRoot(JSTracer *trc, JSObject *thing, const char *name);
+*     This function is only valid during the root marking phase of GC (i.e.,
+*     when MarkRuntime is on the stack).
+*
+* MarkObjectUnbarriered(JSTracer *trc, JSObject *thing, const char *name);
+*     Like MarkObject, this function can be called at any time. It is more
+*     forgiving, since it doesn't demand a HeapPtr as an argument. Its use
+*     should always be accompanied by a comment explaining how write barriers
+*     are implemented for the given field.
+*
+* Additionally, the functions MarkObjectRange and MarkObjectRootRange are
+* defined for marking arrays of object pointers.
+*
+* The following functions are provided to test whether a GC thing is marked
+* under different circumstances:
+*
+* IsObjectAboutToBeFinalized(JSObject **thing);
+*     This function is indended to be used in code used to sweep GC things.  It
+*     indicates whether the object will will be finialized in the current group
+*     of compartments being swept.  Note that this will return false for any
+*     object not in the group of compartments currently being swept, as even if
+*     it is unmarked it may still become marked before it is swept.
+*
+* IsObjectMarked(JSObject **thing);
+*     This function is indended to be used in rare cases in code used to mark
+*     GC things.  It indicates whether the object is currently marked.
+*
+* UpdateObjectIfRelocated(JSObject **thingp);
+*     In some circumstances -- e.g. optional weak marking -- it is necessary
+*     to look at the pointer before marking it strongly or weakly. In these
+*     cases, the following must be called to update the pointer before use.
+*/
+#define DeclMarker(base, type)                                                                    \
+void Mark##base(JSTracer *trc, BarrieredPtr<type> *thing, const char *name);                      \
+void Mark##base##Root(JSTracer *trc, type **thingp, const char *name);                            \
+void Mark##base##Unbarriered(JSTracer *trc, type **thingp, const char *name);                     \
+void Mark##base##Range(JSTracer *trc, size_t len, HeapPtr<type> *thing, const char *name);        \
+void Mark##base##RootRange(JSTracer *trc, size_t len, type **thing, const char *name);            \
+bool Is##base##Marked(type **thingp);                                                             \
+bool Is##base##Marked(BarrieredPtr<type> *thingp);                                                \
+bool Is##base##AboutToBeFinalized(type **thingp);                                                 \
+bool Is##base##AboutToBeFinalized(BarrieredPtr<type> *thingp);                                    \
+type *Update##base##IfRelocated(JSRuntime *rt, BarrieredPtr<type> *thingp);                       \
+type *Update##base##IfRelocated(JSRuntime *rt, type **thingp);
+DeclMarker(BaseShape, BaseShape)
+DeclMarker(BaseShape, UnownedBaseShape)
+DeclMarker(JitCode, jit::JitCode)
+DeclMarker(Object, ArgumentsObject)
+DeclMarker(Object, ArrayBufferObject)
+DeclMarker(Object, ArrayBufferViewObject)
+DeclMarker(Object, SharedArrayBufferObject)
+DeclMarker(Object, DebugScopeObject)
+DeclMarker(Object, GlobalObject)
+DeclMarker(Object, JSObject)
+DeclMarker(Object, JSFunction)
+DeclMarker(Object, ScopeObject)
+DeclMarker(Script, JSScript)
+DeclMarker(LazyScript, LazyScript)
+DeclMarker(Shape, Shape)
+DeclMarker(String, JSAtom)
+DeclMarker(String, JSString)
+DeclMarker(String, JSFlatString)
+DeclMarker(String, JSLinearString)
+DeclMarker(String, PropertyName)
+DeclMarker(TypeObject, types::TypeObject)
+#undef DeclMarker
+void
+MarkPermanentAtom(JSTracer *trc, JSAtom *atom, const char *name);
+/* Return true if the pointer is nullptr, or if it is a tagged pointer to
+* nullptr.
+*/
+MOZ_ALWAYS_INLINE bool
+IsNullTaggedPointer(void *p)
+{
+return uintptr_t(p) < 32;
+}
+/*** Externally Typed Marking ***/
+/*
+* Note: this must only be called by the GC and only when we are tracing through
+* MarkRoots. It is explicitly for ConservativeStackMarking and should go away
+* after we transition to exact rooting.
+*/
+void
+MarkKind(JSTracer *trc, void **thingp, JSGCTraceKind kind);
+void
+MarkGCThingRoot(JSTracer *trc, void **thingp, const char *name);
+void
+MarkGCThingUnbarriered(JSTracer *trc, void **thingp, const char *name);
+/*** ID Marking ***/
+void
+MarkId(JSTracer *trc, BarrieredId *id, const char *name);
+void
+MarkIdRoot(JSTracer *trc, jsid *id, const char *name);
+void
+MarkIdUnbarriered(JSTracer *trc, jsid *id, const char *name);
+void
+MarkIdRange(JSTracer *trc, size_t len, HeapId *vec, const char *name);
+void
+MarkIdRootRange(JSTracer *trc, size_t len, jsid *vec, const char *name);
+/*** Value Marking ***/
+void
+MarkValue(JSTracer *trc, BarrieredValue *v, const char *name);
+void
+MarkValueRange(JSTracer *trc, size_t len, BarrieredValue *vec, const char *name);
+inline void
+MarkValueRange(JSTracer *trc, HeapValue *begin, HeapValue *end, const char *name)
+{
+return MarkValueRange(trc, end - begin, begin, name);
+}
+void
+MarkValueRoot(JSTracer *trc, Value *v, const char *name);
+void
+MarkThingOrValueUnbarriered(JSTracer *trc, uintptr_t *word, const char *name);
+void
+MarkValueRootRange(JSTracer *trc, size_t len, Value *vec, const char *name);
+inline void
+MarkValueRootRange(JSTracer *trc, Value *begin, Value *end, const char *name)
+{
+MarkValueRootRange(trc, end - begin, begin, name);
+}
+void
+MarkTypeRoot(JSTracer *trc, types::Type *v, const char *name);
+bool
+IsValueMarked(Value *v);
+bool
+IsValueAboutToBeFinalized(Value *v);
+/*** Slot Marking ***/
+bool
+IsSlotMarked(HeapSlot *s);
+void
+MarkSlot(JSTracer *trc, HeapSlot *s, const char *name);
+void
+MarkArraySlots(JSTracer *trc, size_t len, HeapSlot *vec, const char *name);
+void
+MarkObjectSlots(JSTracer *trc, JSObject *obj, uint32_t start, uint32_t nslots);
+void
+MarkCrossCompartmentObjectUnbarriered(JSTracer *trc, JSObject *src, JSObject **dst_obj,
+const char *name);
+void
+MarkCrossCompartmentScriptUnbarriered(JSTracer *trc, JSObject *src, JSScript **dst_script,
+const char *name);
+/*
+* Mark a value that may be in a different compartment from the compartment
+* being GC'd. (Although it won't be marked if it's in the wrong compartment.)
+*/
+void
+MarkCrossCompartmentSlot(JSTracer *trc, JSObject *src, HeapSlot *dst_slot, const char *name);
+/*** Special Cases ***/
+/*
+* The unioned HeapPtr stored in script->globalObj needs special treatment to
+* typecheck correctly.
+*/
+void
+MarkObject(JSTracer *trc, HeapPtr<GlobalObject, JSScript *> *thingp, const char *name);
+/*
+* MarkChildren<JSObject> is exposed solely for preWriteBarrier on
+* JSObject::TradeGuts. It should not be considered external interface.
+*/
+void
+MarkChildren(JSTracer *trc, JSObject *obj);
+/*
+* Trace through the shape and any shapes it contains to mark
+* non-shape children. This is exposed to the JS API as
+* JS_TraceShapeCycleCollectorChildren.
+*/
+void
+MarkCycleCollectorChildren(JSTracer *trc, Shape *shape);
+void
+PushArena(GCMarker *gcmarker, ArenaHeader *aheader);
+/*** Generic ***/
+/*
+* The Mark() functions interface should only be used by code that must be
+* templated.  Other uses should use the more specific, type-named functions.
+*/
+inline void
+Mark(JSTracer *trc, BarrieredValue *v, const char *name)
+{
+MarkValue(trc, v, name);
+}
+inline void
+Mark(JSTracer *trc, BarrieredPtrObject *o, const char *name)
+{
+MarkObject(trc, o, name);
+}
+inline void
+Mark(JSTracer *trc, BarrieredPtrScript *o, const char *name)
+{
+MarkScript(trc, o, name);
+}
+inline void
+Mark(JSTracer *trc, HeapPtr<jit::JitCode> *code, const char *name)
+{
+MarkJitCode(trc, code, name);
+}
+/* For use by WeakMap's HashKeyRef instantiation. */
+inline void
+Mark(JSTracer *trc, JSObject **objp, const char *name)
+{
+MarkObjectUnbarriered(trc, objp, name);
+}
+/* For use by Debugger::WeakMap's proxiedScopes HashKeyRef instantiation. */
+inline void
+Mark(JSTracer *trc, ScopeObject **obj, const char *name)
+{
+MarkObjectUnbarriered(trc, obj, name);
+}
+bool
+IsCellMarked(Cell **thingp);
+bool
+IsCellAboutToBeFinalized(Cell **thing);
+inline bool
+IsMarked(BarrieredValue *v)
+{
+if (!v->isMarkable())
+return true;
+return IsValueMarked(v->unsafeGet());
+}
+inline bool
+IsMarked(BarrieredPtrObject *objp)
+{
+return IsObjectMarked(objp);
+}
+inline bool
+IsMarked(BarrieredPtrScript *scriptp)
+{
+return IsScriptMarked(scriptp);
+}
+inline bool
+IsAboutToBeFinalized(BarrieredValue *v)
+{
+if (!v->isMarkable())
+return false;
+return IsValueAboutToBeFinalized(v->unsafeGet());
+}
+inline bool
+IsAboutToBeFinalized(BarrieredPtrObject *objp)
+{
+return IsObjectAboutToBeFinalized(objp);
+}
+inline bool
+IsAboutToBeFinalized(BarrieredPtrScript *scriptp)
+{
+return IsScriptAboutToBeFinalized(scriptp);
+}
+#ifdef JS_ION
+/* Nonsense to get WeakCache to work with new Marking semantics. */
+inline bool
+IsAboutToBeFinalized(const js::jit::VMFunction **vmfunc)
+{
+/*
+* Preserves entries in the WeakCache<VMFunction, JitCode>
+* iff the JitCode has been marked.
+*/
+return true;
+}
+inline bool
+IsAboutToBeFinalized(ReadBarriered<js::jit::JitCode> code)
+{
+return IsJitCodeAboutToBeFinalized(code.unsafeGet());
+}
+#endif
+inline Cell *
+ToMarkable(const Value &v)
+{
+if (v.isMarkable())
+return (Cell *)v.toGCThing();
+return nullptr;
+}
+inline Cell *
+ToMarkable(Cell *cell)
+{
+return cell;
+}
+inline JSGCTraceKind
+TraceKind(const Value &v)
+{
+JS_ASSERT(v.isMarkable());
+if (v.isObject())
+return JSTRACE_OBJECT;
+return JSTRACE_STRING;
+}
+inline JSGCTraceKind
+TraceKind(JSObject *obj)
+{
+return JSTRACE_OBJECT;
+}
+inline JSGCTraceKind
+TraceKind(JSScript *script)
+{
+return JSTRACE_SCRIPT;
+}
+inline JSGCTraceKind
+TraceKind(LazyScript *lazy)
+{
+return JSTRACE_LAZY_SCRIPT;
+}
+} /* namespace gc */
+void
+TraceChildren(JSTracer *trc, void *thing, JSGCTraceKind kind);
+} /* namespace js */
+#endif /* gc_Marking_h */

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comparison: js/src/gc/Marking.h

js/src/gc/Marking.h