The Tor Browser: js/src/vm/ArgumentsObject.cpp@6474c204b198 (annotated)

js/src/vm/ArgumentsObject.cpp@6474c204b198 (annotated)

js/src/vm/ArgumentsObject.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- 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/. */
 #include "vm/ArgumentsObject-inl.h"
 #include "jsinfer.h"
 #ifdef JS_ION
 #include "jit/IonFrames.h"
 #endif
 #include "vm/GlobalObject.h"
 #include "vm/Stack.h"
 #include "jsobjinlines.h"
 #include "vm/Stack-inl.h"
 using namespace js;
 using namespace js::gc;
 static void
 CopyStackFrameArguments(const AbstractFramePtr frame, HeapValue *dst, unsigned totalArgs)
 {
     JS_ASSERT_IF(frame.isInterpreterFrame(), !frame.asInterpreterFrame()->runningInJit());
     JS_ASSERT(Max(frame.numActualArgs(), frame.numFormalArgs()) == totalArgs);
     /* Copy arguments. */
     Value *src = frame.argv();
     Value *end = src + totalArgs;
     while (src != end)
         (dst++)->init(*src++);
 }
 /* static */ void
 ArgumentsObject::MaybeForwardToCallObject(AbstractFramePtr frame, JSObject *obj,
                                           ArgumentsData *data)
 {
     JSScript *script = frame.script();
     if (frame.fun()->isHeavyweight() && script->argsObjAliasesFormals()) {
         obj->initFixedSlot(MAYBE_CALL_SLOT, ObjectValue(frame.callObj()));
         for (AliasedFormalIter fi(script); fi; fi++)
             data->args[fi.frameIndex()] = JS::MagicValueUint32(fi.scopeSlot());
     }
 }
 #if defined(JS_ION)
 /* static */ void
 ArgumentsObject::MaybeForwardToCallObject(jit::IonJSFrameLayout *frame, HandleObject callObj,
                                           JSObject *obj, ArgumentsData *data)
 {
     JSFunction *callee = jit::CalleeTokenToFunction(frame->calleeToken());
     JSScript *script = callee->nonLazyScript();
     if (callee->isHeavyweight() && script->argsObjAliasesFormals()) {
         JS_ASSERT(callObj && callObj->is<CallObject>());
         obj->initFixedSlot(MAYBE_CALL_SLOT, ObjectValue(*callObj.get()));
         for (AliasedFormalIter fi(script); fi; fi++)
             data->args[fi.frameIndex()] = JS::MagicValueUint32(fi.scopeSlot());
     }
 }
 #endif
 struct CopyFrameArgs
 {
     AbstractFramePtr frame_;
     CopyFrameArgs(AbstractFramePtr frame)
       : frame_(frame)
     { }
     void copyArgs(JSContext *, HeapValue *dst, unsigned totalArgs) const {
         CopyStackFrameArguments(frame_, dst, totalArgs);
     }
     /*
      * If a call object exists and the arguments object aliases formals, the
      * call object is the canonical location for formals.
      */
     void maybeForwardToCallObject(JSObject *obj, ArgumentsData *data) {
         ArgumentsObject::MaybeForwardToCallObject(frame_, obj, data);
     }
 };
 #if defined(JS_ION)
 struct CopyIonJSFrameArgs
 {
     jit::IonJSFrameLayout *frame_;
     HandleObject callObj_;
     CopyIonJSFrameArgs(jit::IonJSFrameLayout *frame, HandleObject callObj)
       : frame_(frame), callObj_(callObj)
     { }
     void copyArgs(JSContext *, HeapValue *dstBase, unsigned totalArgs) const {
         unsigned numActuals = frame_->numActualArgs();
         unsigned numFormals = jit::CalleeTokenToFunction(frame_->calleeToken())->nargs();
         JS_ASSERT(numActuals <= totalArgs);
         JS_ASSERT(numFormals <= totalArgs);
         JS_ASSERT(Max(numActuals, numFormals) == totalArgs);
         /* Copy all arguments. */
         Value *src = frame_->argv() + 1;  /* +1 to skip this. */
         Value *end = src + numActuals;
         HeapValue *dst = dstBase;
         while (src != end)
             (dst++)->init(*src++);
         if (numActuals < numFormals) {
             HeapValue *dstEnd = dstBase + totalArgs;
             while (dst != dstEnd)
                 (dst++)->init(UndefinedValue());
         }
     }
     /*
      * If a call object exists and the arguments object aliases formals, the
      * call object is the canonical location for formals.
      */
     void maybeForwardToCallObject(JSObject *obj, ArgumentsData *data) {
         ArgumentsObject::MaybeForwardToCallObject(frame_, callObj_, obj, data);
     }
 };
 #endif
 struct CopyScriptFrameIterArgs
 {
     ScriptFrameIter &iter_;
     CopyScriptFrameIterArgs(ScriptFrameIter &iter)
       : iter_(iter)
     { }
     void copyArgs(JSContext *cx, HeapValue *dstBase, unsigned totalArgs) const {
         /* Copy actual arguments. */
         iter_.unaliasedForEachActual(cx, CopyToHeap(dstBase));
         /* Define formals which are not part of the actuals. */
         unsigned numActuals = iter_.numActualArgs();
         unsigned numFormals = iter_.callee()->nargs();
         JS_ASSERT(numActuals <= totalArgs);
         JS_ASSERT(numFormals <= totalArgs);
         JS_ASSERT(Max(numActuals, numFormals) == totalArgs);
         if (numActuals < numFormals) {
             HeapValue *dst = dstBase + numActuals, *dstEnd = dstBase + totalArgs;
             while (dst != dstEnd)
                 (dst++)->init(UndefinedValue());
         }
     }
     /*
      * Ion frames are copying every argument onto the stack, other locations are
      * invalid.
      */
     void maybeForwardToCallObject(JSObject *obj, ArgumentsData *data) {
         if (!iter_.isJit())
             ArgumentsObject::MaybeForwardToCallObject(iter_.abstractFramePtr(), obj, data);
     }
 };
 template <typename CopyArgs>
 /* static */ ArgumentsObject *
 ArgumentsObject::create(JSContext *cx, HandleScript script, HandleFunction callee, unsigned numActuals,
                         CopyArgs &copy)
 {
     RootedObject proto(cx, callee->global().getOrCreateObjectPrototype(cx));
     if (!proto)
         return nullptr;
     bool strict = callee->strict();
     const Class *clasp = strict ? &StrictArgumentsObject::class_ : &NormalArgumentsObject::class_;
     RootedTypeObject type(cx, cx->getNewType(clasp, proto.get()));
     if (!type)
         return nullptr;
     JSObject *metadata = nullptr;
     if (!NewObjectMetadata(cx, &metadata))
         return nullptr;
     RootedShape shape(cx, EmptyShape::getInitialShape(cx, clasp, TaggedProto(proto),
                                                       proto->getParent(), metadata, FINALIZE_KIND,
                                                       BaseShape::INDEXED));
     if (!shape)
         return nullptr;
     unsigned numFormals = callee->nargs();
     unsigned numDeletedWords = NumWordsForBitArrayOfLength(numActuals);
     unsigned numArgs = Max(numActuals, numFormals);
     unsigned numBytes = offsetof(ArgumentsData, args) +
                         numDeletedWords * sizeof(size_t) +
                         numArgs * sizeof(Value);
     ArgumentsData *data = (ArgumentsData *)cx->malloc_(numBytes);
     if (!data)
         return nullptr;
     JSObject *obj = JSObject::create(cx, FINALIZE_KIND, GetInitialHeap(GenericObject, clasp),
                                      shape, type);
     if (!obj) {
         js_free(data);
         return nullptr;
     }
     data->numArgs = numArgs;
     data->callee.init(ObjectValue(*callee.get()));
     data->script = script;
     /* Copy [0, numArgs) into data->slots. */
     HeapValue *dst = data->args, *dstEnd = data->args + numArgs;
     copy.copyArgs(cx, dst, numArgs);
     data->deletedBits = reinterpret_cast<size_t *>(dstEnd);
     ClearAllBitArrayElements(data->deletedBits, numDeletedWords);
     obj->initFixedSlot(INITIAL_LENGTH_SLOT, Int32Value(numActuals << PACKED_BITS_COUNT));
     obj->initFixedSlot(DATA_SLOT, PrivateValue(data));
     copy.maybeForwardToCallObject(obj, data);
     ArgumentsObject &argsobj = obj->as<ArgumentsObject>();
     JS_ASSERT(argsobj.initialLength() == numActuals);
     JS_ASSERT(!argsobj.hasOverriddenLength());
     return &argsobj;
 }
 ArgumentsObject *
 ArgumentsObject::createExpected(JSContext *cx, AbstractFramePtr frame)
 {
     JS_ASSERT(frame.script()->needsArgsObj());
     RootedScript script(cx, frame.script());
     RootedFunction callee(cx, frame.callee());
     CopyFrameArgs copy(frame);
     ArgumentsObject *argsobj = create(cx, script, callee, frame.numActualArgs(), copy);
     if (!argsobj)
         return nullptr;
     frame.initArgsObj(*argsobj);
     return argsobj;
 }
 ArgumentsObject *
 ArgumentsObject::createUnexpected(JSContext *cx, ScriptFrameIter &iter)
 {
     RootedScript script(cx, iter.script());
     RootedFunction callee(cx, iter.callee());
     CopyScriptFrameIterArgs copy(iter);
     return create(cx, script, callee, iter.numActualArgs(), copy);
 }
 ArgumentsObject *
 ArgumentsObject::createUnexpected(JSContext *cx, AbstractFramePtr frame)
 {
     RootedScript script(cx, frame.script());
     RootedFunction callee(cx, frame.callee());
     CopyFrameArgs copy(frame);
     return create(cx, script, callee, frame.numActualArgs(), copy);
 }
 #if defined(JS_ION)
 ArgumentsObject *
 ArgumentsObject::createForIon(JSContext *cx, jit::IonJSFrameLayout *frame, HandleObject scopeChain)
 {
     jit::CalleeToken token = frame->calleeToken();
     JS_ASSERT(jit::CalleeTokenIsFunction(token));
     RootedScript script(cx, jit::ScriptFromCalleeToken(token));
     RootedFunction callee(cx, jit::CalleeTokenToFunction(token));
     RootedObject callObj(cx, scopeChain->is<CallObject>() ? scopeChain.get() : nullptr);
     CopyIonJSFrameArgs copy(frame, callObj);
     return create(cx, script, callee, frame->numActualArgs(), copy);
 }
 #endif
 static bool
 args_delProperty(JSContext *cx, HandleObject obj, HandleId id, bool *succeeded)
 {
     ArgumentsObject &argsobj = obj->as<ArgumentsObject>();
     if (JSID_IS_INT(id)) {
         unsigned arg = unsigned(JSID_TO_INT(id));
         if (arg < argsobj.initialLength() && !argsobj.isElementDeleted(arg))
             argsobj.markElementDeleted(arg);
     } else if (JSID_IS_ATOM(id, cx->names().length)) {
         argsobj.markLengthOverridden();
     } else if (JSID_IS_ATOM(id, cx->names().callee)) {
         argsobj.as<NormalArgumentsObject>().clearCallee();
     }
     *succeeded = true;
     return true;
 }
 static bool
 ArgGetter(JSContext *cx, HandleObject obj, HandleId id, MutableHandleValue vp)
 {
     if (!obj->is<NormalArgumentsObject>())
         return true;
     NormalArgumentsObject &argsobj = obj->as<NormalArgumentsObject>();
     if (JSID_IS_INT(id)) {
         /*
          * arg can exceed the number of arguments if a script changed the
          * prototype to point to another Arguments object with a bigger argc.
          */
         unsigned arg = unsigned(JSID_TO_INT(id));
         if (arg < argsobj.initialLength() && !argsobj.isElementDeleted(arg))
             vp.set(argsobj.element(arg));
     } else if (JSID_IS_ATOM(id, cx->names().length)) {
         if (!argsobj.hasOverriddenLength())
             vp.setInt32(argsobj.initialLength());
     } else {
         JS_ASSERT(JSID_IS_ATOM(id, cx->names().callee));
         if (!argsobj.callee().isMagic(JS_OVERWRITTEN_CALLEE))
             vp.set(argsobj.callee());
     }
     return true;
 }
 static bool
 ArgSetter(JSContext *cx, HandleObject obj, HandleId id, bool strict, MutableHandleValue vp)
 {
     if (!obj->is<NormalArgumentsObject>())
         return true;
     unsigned attrs;
     if (!baseops::GetAttributes(cx, obj, id, &attrs))
         return false;
     JS_ASSERT(!(attrs & JSPROP_READONLY));
     attrs &= (JSPROP_ENUMERATE | JSPROP_PERMANENT); /* only valid attributes */
     NormalArgumentsObject &argsobj = obj->as<NormalArgumentsObject>();
     RootedScript script(cx, argsobj.containingScript());
     if (JSID_IS_INT(id)) {
         unsigned arg = unsigned(JSID_TO_INT(id));
         if (arg < argsobj.initialLength() && !argsobj.isElementDeleted(arg)) {
             argsobj.setElement(cx, arg, vp);
             if (arg < script->functionNonDelazifying()->nargs())
                 types::TypeScript::SetArgument(cx, script, arg, vp);
             return true;
         }
     } else {
         JS_ASSERT(JSID_IS_ATOM(id, cx->names().length) || JSID_IS_ATOM(id, cx->names().callee));
     }
     /*
      * For simplicity we use delete/define to replace the property with one
      * backed by the default Object getter and setter. Note that we rely on
      * args_delProperty to clear the corresponding reserved slot so the GC can
      * collect its value. Note also that we must define the property instead
      * of setting it in case the user has changed the prototype to an object
      * that has a setter for this id.
      */
     bool succeeded;
     return baseops::DeleteGeneric(cx, obj, id, &succeeded) &&
            baseops::DefineGeneric(cx, obj, id, vp, nullptr, nullptr, attrs);
 }
 static bool
 args_resolve(JSContext *cx, HandleObject obj, HandleId id, MutableHandleObject objp)
 {
     objp.set(nullptr);
     Rooted<NormalArgumentsObject*> argsobj(cx, &obj->as<NormalArgumentsObject>());
     unsigned attrs = JSPROP_SHARED | JSPROP_SHADOWABLE;
     if (JSID_IS_INT(id)) {
         uint32_t arg = uint32_t(JSID_TO_INT(id));
         if (arg >= argsobj->initialLength() || argsobj->isElementDeleted(arg))
             return true;
         attrs |= JSPROP_ENUMERATE;
     } else if (JSID_IS_ATOM(id, cx->names().length)) {
         if (argsobj->hasOverriddenLength())
             return true;
     } else {
         if (!JSID_IS_ATOM(id, cx->names().callee))
             return true;
         if (argsobj->callee().isMagic(JS_OVERWRITTEN_CALLEE))
             return true;
     }
     if (!baseops::DefineGeneric(cx, argsobj, id, UndefinedHandleValue, ArgGetter, ArgSetter, attrs))
         return false;
     objp.set(argsobj);
     return true;
 }
 static bool
 args_enumerate(JSContext *cx, HandleObject obj)
 {
     Rooted<NormalArgumentsObject*> argsobj(cx, &obj->as<NormalArgumentsObject>());
     RootedId id(cx);
     /*
      * Trigger reflection in args_resolve using a series of js_LookupProperty
      * calls.
      */
     int argc = int(argsobj->initialLength());
     for (int i = -2; i != argc; i++) {
         id = (i == -2)
              ? NameToId(cx->names().length)
              : (i == -1)
              ? NameToId(cx->names().callee)
              : INT_TO_JSID(i);
         RootedObject pobj(cx);
         RootedShape prop(cx);
         if (!baseops::LookupProperty<CanGC>(cx, argsobj, id, &pobj, &prop))
             return false;
     }
     return true;
 }
 static bool
 StrictArgGetter(JSContext *cx, HandleObject obj, HandleId id, MutableHandleValue vp)
 {
     if (!obj->is<StrictArgumentsObject>())
         return true;
     StrictArgumentsObject &argsobj = obj->as<StrictArgumentsObject>();
     if (JSID_IS_INT(id)) {
         /*
          * arg can exceed the number of arguments if a script changed the
          * prototype to point to another Arguments object with a bigger argc.
          */
         unsigned arg = unsigned(JSID_TO_INT(id));
         if (arg < argsobj.initialLength() && !argsobj.isElementDeleted(arg))
             vp.set(argsobj.element(arg));
     } else {
         JS_ASSERT(JSID_IS_ATOM(id, cx->names().length));
         if (!argsobj.hasOverriddenLength())
             vp.setInt32(argsobj.initialLength());
     }
     return true;
 }
 static bool
 StrictArgSetter(JSContext *cx, HandleObject obj, HandleId id, bool strict, MutableHandleValue vp)
 {
     if (!obj->is<StrictArgumentsObject>())
         return true;
     unsigned attrs;
     if (!baseops::GetAttributes(cx, obj, id, &attrs))
         return false;
     JS_ASSERT(!(attrs & JSPROP_READONLY));
     attrs &= (JSPROP_ENUMERATE | JSPROP_PERMANENT); /* only valid attributes */
     Rooted<StrictArgumentsObject*> argsobj(cx, &obj->as<StrictArgumentsObject>());
     if (JSID_IS_INT(id)) {
         unsigned arg = unsigned(JSID_TO_INT(id));
         if (arg < argsobj->initialLength()) {
             argsobj->setElement(cx, arg, vp);
             return true;
         }
     } else {
         JS_ASSERT(JSID_IS_ATOM(id, cx->names().length));
     }
     /*
      * For simplicity we use delete/define to replace the property with one
      * backed by the default Object getter and setter. Note that we rely on
      * args_delProperty to clear the corresponding reserved slot so the GC can
      * collect its value.
      */
     bool succeeded;
     return baseops::DeleteGeneric(cx, argsobj, id, &succeeded) &&
            baseops::DefineGeneric(cx, argsobj, id, vp, nullptr, nullptr, attrs);
 }
 static bool
 strictargs_resolve(JSContext *cx, HandleObject obj, HandleId id, MutableHandleObject objp)
 {
     objp.set(nullptr);
     Rooted<StrictArgumentsObject*> argsobj(cx, &obj->as<StrictArgumentsObject>());
     unsigned attrs = JSPROP_SHARED | JSPROP_SHADOWABLE;
     PropertyOp getter = StrictArgGetter;
     StrictPropertyOp setter = StrictArgSetter;
     if (JSID_IS_INT(id)) {
         uint32_t arg = uint32_t(JSID_TO_INT(id));
         if (arg >= argsobj->initialLength() || argsobj->isElementDeleted(arg))
             return true;
         attrs |= JSPROP_ENUMERATE;
     } else if (JSID_IS_ATOM(id, cx->names().length)) {
         if (argsobj->hasOverriddenLength())
             return true;
     } else {
         if (!JSID_IS_ATOM(id, cx->names().callee) && !JSID_IS_ATOM(id, cx->names().caller))
             return true;
         attrs = JSPROP_PERMANENT | JSPROP_GETTER | JSPROP_SETTER | JSPROP_SHARED;
         getter = CastAsPropertyOp(argsobj->global().getThrowTypeError());
         setter = CastAsStrictPropertyOp(argsobj->global().getThrowTypeError());
     }
     if (!baseops::DefineGeneric(cx, argsobj, id, UndefinedHandleValue, getter, setter, attrs))
         return false;
     objp.set(argsobj);
     return true;
 }
 static bool
 strictargs_enumerate(JSContext *cx, HandleObject obj)
 {
     Rooted<StrictArgumentsObject*> argsobj(cx, &obj->as<StrictArgumentsObject>());
     /*
      * Trigger reflection in strictargs_resolve using a series of
      * js_LookupProperty calls.
      */
     RootedObject pobj(cx);
     RootedShape prop(cx);
     RootedId id(cx);
     // length
     id = NameToId(cx->names().length);
     if (!baseops::LookupProperty<CanGC>(cx, argsobj, id, &pobj, &prop))
         return false;
     // callee
     id = NameToId(cx->names().callee);
     if (!baseops::LookupProperty<CanGC>(cx, argsobj, id, &pobj, &prop))
         return false;
     // caller
     id = NameToId(cx->names().caller);
     if (!baseops::LookupProperty<CanGC>(cx, argsobj, id, &pobj, &prop))
         return false;
     for (uint32_t i = 0, argc = argsobj->initialLength(); i < argc; i++) {
         id = INT_TO_JSID(i);
         if (!baseops::LookupProperty<CanGC>(cx, argsobj, id, &pobj, &prop))
             return false;
     }
     return true;
 }
 void
 ArgumentsObject::finalize(FreeOp *fop, JSObject *obj)
 {
     fop->free_(reinterpret_cast<void *>(obj->as<ArgumentsObject>().data()));
 }
 void
 ArgumentsObject::trace(JSTracer *trc, JSObject *obj)
 {
     ArgumentsObject &argsobj = obj->as<ArgumentsObject>();
     ArgumentsData *data = argsobj.data();
     MarkValue(trc, &data->callee, js_callee_str);
     MarkValueRange(trc, data->numArgs, data->args, js_arguments_str);
     MarkScriptUnbarriered(trc, &data->script, "script");
 }
 /*
  * The classes below collaborate to lazily reflect and synchronize actual
  * argument values, argument count, and callee function object stored in a
  * stack frame with their corresponding property values in the frame's
  * arguments object.
  */
 const Class NormalArgumentsObject::class_ = {
     "Arguments",
     JSCLASS_NEW_RESOLVE | JSCLASS_IMPLEMENTS_BARRIERS |
     JSCLASS_HAS_RESERVED_SLOTS(NormalArgumentsObject::RESERVED_SLOTS) |
     JSCLASS_HAS_CACHED_PROTO(JSProto_Object) | JSCLASS_BACKGROUND_FINALIZE,
     JS_PropertyStub,         /* addProperty */
     args_delProperty,
     JS_PropertyStub,         /* getProperty */
     JS_StrictPropertyStub,   /* setProperty */
     args_enumerate,
     reinterpret_cast<JSResolveOp>(args_resolve),
     JS_ConvertStub,
     ArgumentsObject::finalize,
     nullptr,                 /* call        */
     nullptr,                 /* hasInstance */
     nullptr,                 /* construct   */
     ArgumentsObject::trace
 };
 /*
  * Strict mode arguments is significantly less magical than non-strict mode
  * arguments, so it is represented by a different class while sharing some
  * functionality.
  */
 const Class StrictArgumentsObject::class_ = {
     "Arguments",
     JSCLASS_NEW_RESOLVE | JSCLASS_IMPLEMENTS_BARRIERS |
     JSCLASS_HAS_RESERVED_SLOTS(StrictArgumentsObject::RESERVED_SLOTS) |
     JSCLASS_HAS_CACHED_PROTO(JSProto_Object) | JSCLASS_BACKGROUND_FINALIZE,
     JS_PropertyStub,         /* addProperty */
     args_delProperty,
     JS_PropertyStub,         /* getProperty */
     JS_StrictPropertyStub,   /* setProperty */
     strictargs_enumerate,
     reinterpret_cast<JSResolveOp>(strictargs_resolve),
     JS_ConvertStub,
     ArgumentsObject::finalize,
     nullptr,                 /* call        */
     nullptr,                 /* hasInstance */
     nullptr,                 /* construct   */
     ArgumentsObject::trace
 };

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js/src/vm/ArgumentsObject.cpp@6474c204b198 (annotated)

js/src/vm/ArgumentsObject.cpp