diff options
Diffstat (limited to 'src/third_party/mozjs-60/extract/js/src/jsarray.cpp')
| -rw-r--r-- | src/third_party/mozjs-60/extract/js/src/jsarray.cpp | 4247 |
1 files changed, 4247 insertions, 0 deletions
diff --git a/src/third_party/mozjs-60/extract/js/src/jsarray.cpp b/src/third_party/mozjs-60/extract/js/src/jsarray.cpp new file mode 100644 index 00000000000..98228f5ff27 --- /dev/null +++ b/src/third_party/mozjs-60/extract/js/src/jsarray.cpp @@ -0,0 +1,4247 @@ +/* -*- 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 "jsarrayinlines.h" + +#include "mozilla/ArrayUtils.h" +#include "mozilla/CheckedInt.h" +#include "mozilla/DebugOnly.h" +#include "mozilla/MathAlgorithms.h" + +#include <algorithm> + +#include "jsapi.h" +#include "jsfriendapi.h" +#include "jsnum.h" +#include "jstypes.h" +#include "jsutil.h" + +#include "ds/Sort.h" +#include "gc/Heap.h" +#include "jit/InlinableNatives.h" +#include "js/Class.h" +#include "js/Conversions.h" +#include "util/StringBuffer.h" +#include "util/Text.h" +#include "vm/ArgumentsObject.h" +#include "vm/Interpreter.h" +#include "vm/Iteration.h" +#include "vm/JSAtom.h" +#include "vm/JSContext.h" +#include "vm/JSFunction.h" +#include "vm/JSObject.h" +#include "vm/SelfHosting.h" +#include "vm/Shape.h" +#include "vm/TypedArrayObject.h" +#include "vm/WrapperObject.h" + +#include "vm/ArgumentsObject-inl.h" +#include "vm/ArrayObject-inl.h" +#include "vm/Caches-inl.h" +#include "vm/GeckoProfiler-inl.h" +#include "vm/Interpreter-inl.h" +#include "vm/JSAtom-inl.h" +#include "vm/NativeObject-inl.h" +#include "vm/UnboxedObject-inl.h" + +using namespace js; +using namespace js::gc; + +using mozilla::Abs; +using mozilla::ArrayLength; +using mozilla::CeilingLog2; +using mozilla::CheckedInt; +using mozilla::DebugOnly; + +using JS::AutoCheckCannotGC; +using JS::IsArrayAnswer; +using JS::ToUint32; + +bool +JS::IsArray(JSContext* cx, HandleObject obj, IsArrayAnswer* answer) +{ + if (obj->is<ArrayObject>()) { + *answer = IsArrayAnswer::Array; + return true; + } + + if (obj->is<ProxyObject>()) + return Proxy::isArray(cx, obj, answer); + + *answer = IsArrayAnswer::NotArray; + return true; +} + +bool +JS::IsArray(JSContext* cx, HandleObject obj, bool* isArray) +{ + IsArrayAnswer answer; + if (!IsArray(cx, obj, &answer)) + return false; + + if (answer == IsArrayAnswer::RevokedProxy) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_PROXY_REVOKED); + return false; + } + + *isArray = answer == IsArrayAnswer::Array; + return true; +} + +// ES2017 7.1.15 ToLength, but clamped to the [0,2^32-2] range. +static bool +ToLengthClamped(JSContext* cx, HandleValue v, uint32_t* out) +{ + if (v.isInt32()) { + int32_t i = v.toInt32(); + *out = i < 0 ? 0 : i; + return true; + } + double d; + if (v.isDouble()) { + d = v.toDouble(); + } else { + if (!ToNumber(cx, v, &d)) + return false; + } + d = JS::ToInteger(d); + if (d <= 0.0) + *out = 0; + else if (d < double(UINT32_MAX - 1)) + *out = uint32_t(d); + else + *out = UINT32_MAX; + return true; +} + +bool +js::GetLengthProperty(JSContext* cx, HandleObject obj, uint32_t* lengthp) +{ + if (obj->is<ArrayObject>()) { + *lengthp = obj->as<ArrayObject>().length(); + return true; + } + + if (obj->is<ArgumentsObject>()) { + ArgumentsObject& argsobj = obj->as<ArgumentsObject>(); + if (!argsobj.hasOverriddenLength()) { + *lengthp = argsobj.initialLength(); + return true; + } + } + + RootedValue value(cx); + if (!GetProperty(cx, obj, obj, cx->names().length, &value)) + return false; + + if (!ToLengthClamped(cx, value, lengthp)) + return false; + + return true; +} + +// ES2017 7.1.15 ToLength. +static bool +ToLength(JSContext* cx, HandleValue v, uint64_t* out) +{ + if (v.isInt32()) { + int32_t i = v.toInt32(); + *out = i < 0 ? 0 : i; + return true; + } + + double d; + if (v.isDouble()) { + d = v.toDouble(); + } else { + if (!ToNumber(cx, v, &d)) + return false; + } + + d = JS::ToInteger(d); + if (d <= 0.0) + *out = 0; + else + *out = uint64_t(Min(d, DOUBLE_INTEGRAL_PRECISION_LIMIT - 1)); + return true; +} + +static MOZ_ALWAYS_INLINE bool +GetLengthProperty(JSContext* cx, HandleObject obj, uint64_t* lengthp) +{ + if (obj->is<ArrayObject>()) { + *lengthp = obj->as<ArrayObject>().length(); + return true; + } + + if (obj->is<ArgumentsObject>()) { + ArgumentsObject& argsobj = obj->as<ArgumentsObject>(); + if (!argsobj.hasOverriddenLength()) { + *lengthp = argsobj.initialLength(); + return true; + } + } + + RootedValue value(cx); + if (!GetProperty(cx, obj, obj, cx->names().length, &value)) + return false; + + return ToLength(cx, value, lengthp); +} + +/* + * Determine if the id represents an array index. + * + * An id is an array index according to ECMA by (15.4): + * + * "Array objects give special treatment to a certain class of property names. + * A property name P (in the form of a string value) is an array index if and + * only if ToString(ToUint32(P)) is equal to P and ToUint32(P) is not equal + * to 2^32-1." + * + * This means the largest allowed index is actually 2^32-2 (4294967294). + * + * In our implementation, it would be sufficient to check for id.isInt32() + * except that by using signed 31-bit integers we miss the top half of the + * valid range. This function checks the string representation itself; note + * that calling a standard conversion routine might allow strings such as + * "08" or "4.0" as array indices, which they are not. + * + */ +template <typename CharT> +static bool +StringIsArrayIndex(const CharT* s, uint32_t length, uint32_t* indexp) +{ + const CharT* end = s + length; + + if (length == 0 || length > (sizeof("4294967294") - 1) || !JS7_ISDEC(*s)) + return false; + + uint32_t c = 0, previous = 0; + uint32_t index = JS7_UNDEC(*s++); + + /* Don't allow leading zeros. */ + if (index == 0 && s != end) + return false; + + for (; s < end; s++) { + if (!JS7_ISDEC(*s)) + return false; + + previous = index; + c = JS7_UNDEC(*s); + index = 10 * index + c; + } + + /* Make sure we didn't overflow. */ + if (previous < (MAX_ARRAY_INDEX / 10) || (previous == (MAX_ARRAY_INDEX / 10) && + c <= (MAX_ARRAY_INDEX % 10))) { + MOZ_ASSERT(index <= MAX_ARRAY_INDEX); + *indexp = index; + return true; + } + + return false; +} + +JS_FRIEND_API(bool) +js::StringIsArrayIndex(JSLinearString* str, uint32_t* indexp) +{ + AutoCheckCannotGC nogc; + return str->hasLatin1Chars() + ? ::StringIsArrayIndex(str->latin1Chars(nogc), str->length(), indexp) + : ::StringIsArrayIndex(str->twoByteChars(nogc), str->length(), indexp); +} + +template <typename T> +static bool +ToId(JSContext* cx, T index, MutableHandleId id); + +template <> +bool +ToId(JSContext* cx, uint32_t index, MutableHandleId id) +{ + return IndexToId(cx, index, id); +} + +template <> +bool +ToId(JSContext* cx, uint64_t index, MutableHandleId id) +{ + MOZ_ASSERT(index < uint64_t(DOUBLE_INTEGRAL_PRECISION_LIMIT)); + + if (index == uint32_t(index)) + return IndexToId(cx, uint32_t(index), id); + + Value tmp = DoubleValue(index); + return ValueToId<CanGC>(cx, HandleValue::fromMarkedLocation(&tmp), id); +} + +/* + * If the property at the given index exists, get its value into |vp| and set + * |*hole| to false. Otherwise set |*hole| to true and |vp| to Undefined. + */ +template <typename T> +static bool +HasAndGetElement(JSContext* cx, HandleObject obj, HandleObject receiver, T index, bool* hole, + MutableHandleValue vp) +{ + if (obj->isNative()) { + NativeObject* nobj = &obj->as<NativeObject>(); + if (index < nobj->getDenseInitializedLength()) { + vp.set(nobj->getDenseElement(size_t(index))); + if (!vp.isMagic(JS_ELEMENTS_HOLE)) { + *hole = false; + return true; + } + } + if (nobj->is<ArgumentsObject>() && index <= UINT32_MAX) { + if (nobj->as<ArgumentsObject>().maybeGetElement(uint32_t(index), vp)) { + *hole = false; + return true; + } + } + } + + RootedId id(cx); + if (!ToId(cx, index, &id)) + return false; + + bool found; + if (!HasProperty(cx, obj, id, &found)) + return false; + + if (found) { + if (!GetProperty(cx, obj, receiver, id, vp)) + return false; + } else { + vp.setUndefined(); + } + *hole = !found; + return true; +} + +template <typename T> +static inline bool +HasAndGetElement(JSContext* cx, HandleObject obj, T index, bool* hole, MutableHandleValue vp) +{ + return HasAndGetElement(cx, obj, obj, index, hole, vp); +} + +bool +ElementAdder::append(JSContext* cx, HandleValue v) +{ + MOZ_ASSERT(index_ < length_); + if (resObj_) { + NativeObject* resObj = &resObj_->as<NativeObject>(); + DenseElementResult result = resObj->setOrExtendDenseElements(cx, index_, v.address(), 1); + if (result == DenseElementResult::Failure) + return false; + if (result == DenseElementResult::Incomplete) { + if (!DefineDataElement(cx, resObj_, index_, v)) + return false; + } + } else { + vp_[index_] = v; + } + index_++; + return true; +} + +void +ElementAdder::appendHole() +{ + MOZ_ASSERT(getBehavior_ == ElementAdder::CheckHasElemPreserveHoles); + MOZ_ASSERT(index_ < length_); + if (!resObj_) + vp_[index_].setMagic(JS_ELEMENTS_HOLE); + index_++; +} + +bool +js::GetElementsWithAdder(JSContext* cx, HandleObject obj, HandleObject receiver, + uint32_t begin, uint32_t end, ElementAdder* adder) +{ + MOZ_ASSERT(begin <= end); + + RootedValue val(cx); + for (uint32_t i = begin; i < end; i++) { + if (adder->getBehavior() == ElementAdder::CheckHasElemPreserveHoles) { + bool hole; + if (!HasAndGetElement(cx, obj, receiver, i, &hole, &val)) + return false; + if (hole) { + adder->appendHole(); + continue; + } + } else { + MOZ_ASSERT(adder->getBehavior() == ElementAdder::GetElement); + if (!GetElement(cx, obj, receiver, i, &val)) + return false; + } + if (!adder->append(cx, val)) + return false; + } + + return true; +} + +static bool +ObjectMayHaveExtraIndexedProperties(JSObject* obj); + +static inline bool +IsPackedArrayOrNoExtraIndexedProperties(JSObject* obj, uint64_t length) +{ + return (IsPackedArray(obj) && obj->as<ArrayObject>().length() == length) || + !ObjectMayHaveExtraIndexedProperties(obj); +} + +static bool +GetDenseElements(NativeObject* aobj, uint32_t length, Value* vp) +{ + MOZ_ASSERT(IsPackedArrayOrNoExtraIndexedProperties(aobj, length)); + + if (length > aobj->getDenseInitializedLength()) + return false; + + for (size_t i = 0; i < length; i++) { + vp[i] = aobj->getDenseElement(i); + + // No other indexed properties so hole => undefined. + if (vp[i].isMagic(JS_ELEMENTS_HOLE)) + vp[i] = UndefinedValue(); + } + + return true; +} + +bool +js::GetElements(JSContext* cx, HandleObject aobj, uint32_t length, Value* vp) +{ + if (IsPackedArrayOrNoExtraIndexedProperties(aobj, length)) { + if (GetDenseElements(&aobj->as<NativeObject>(), length, vp)) + return true; + } + + if (aobj->is<ArgumentsObject>()) { + ArgumentsObject& argsobj = aobj->as<ArgumentsObject>(); + if (!argsobj.hasOverriddenLength()) { + if (argsobj.maybeGetElements(0, length, vp)) + return true; + } + } + + if (aobj->is<TypedArrayObject>()) { + TypedArrayObject* typedArray = &aobj->as<TypedArrayObject>(); + if (typedArray->length() == length) { + typedArray->getElements(vp); + return true; + } + } + + if (js::GetElementsOp op = aobj->getOpsGetElements()) { + ElementAdder adder(cx, vp, length, ElementAdder::GetElement); + return op(cx, aobj, 0, length, &adder); + } + + for (uint32_t i = 0; i < length; i++) { + if (!GetElement(cx, aobj, aobj, i, MutableHandleValue::fromMarkedLocation(&vp[i]))) + return false; + } + + return true; +} + +static inline bool +GetArrayElement(JSContext* cx, HandleObject obj, uint64_t index, MutableHandleValue vp) +{ + if (obj->isNative()) { + NativeObject* nobj = &obj->as<NativeObject>(); + if (index < nobj->getDenseInitializedLength()) { + vp.set(nobj->getDenseElement(size_t(index))); + if (!vp.isMagic(JS_ELEMENTS_HOLE)) + return true; + } + + if (nobj->is<ArgumentsObject>() && index <= UINT32_MAX) { + if (nobj->as<ArgumentsObject>().maybeGetElement(uint32_t(index), vp)) + return true; + } + } + + RootedId id(cx); + if (!ToId(cx, index, &id)) + return false; + return GetProperty(cx, obj, obj, id, vp); +} + +static inline bool +DefineArrayElement(JSContext* cx, HandleObject obj, uint64_t index, HandleValue value) +{ + RootedId id(cx); + if (!ToId(cx, index, &id)) + return false; + return DefineDataProperty(cx, obj, id, value); +} + +// Set the value of the property at the given index to v. +static inline bool +SetArrayElement(JSContext* cx, HandleObject obj, uint64_t index, HandleValue v) +{ + RootedId id(cx); + if (!ToId(cx, index, &id)) + return false; + + return SetProperty(cx, obj, id, v); +} + +/* + * Attempt to delete the element |index| from |obj| as if by + * |obj.[[Delete]](index)|. + * + * If an error occurs while attempting to delete the element (that is, the call + * to [[Delete]] threw), return false. + * + * Otherwise call result.succeed() or result.fail() to indicate whether the + * deletion attempt succeeded (that is, whether the call to [[Delete]] returned + * true or false). (Deletes generally fail only when the property is + * non-configurable, but proxies may implement different semantics.) + */ +static bool +DeleteArrayElement(JSContext* cx, HandleObject obj, uint64_t index, ObjectOpResult& result) +{ + if (obj->is<ArrayObject>() && + !obj->as<NativeObject>().isIndexed() && + !obj->as<NativeObject>().denseElementsAreFrozen()) + { + ArrayObject* aobj = &obj->as<ArrayObject>(); + if (index <= UINT32_MAX) { + uint32_t idx = uint32_t(index); + if (idx < aobj->getDenseInitializedLength()) { + if (!aobj->maybeCopyElementsForWrite(cx)) + return false; + if (idx+1 == aobj->getDenseInitializedLength()) { + aobj->setDenseInitializedLength(idx); + } else { + aobj->markDenseElementsNotPacked(cx); + aobj->setDenseElement(idx, MagicValue(JS_ELEMENTS_HOLE)); + } + if (!SuppressDeletedElement(cx, obj, idx)) + return false; + } + } + + return result.succeed(); + } + + RootedId id(cx); + if (!ToId(cx, index, &id)) + return false; + return DeleteProperty(cx, obj, id, result); +} + +/* ES6 draft rev 32 (2 Febr 2015) 7.3.7 */ +static bool +DeletePropertyOrThrow(JSContext* cx, HandleObject obj, uint64_t index) +{ + ObjectOpResult success; + if (!DeleteArrayElement(cx, obj, index, success)) + return false; + if (!success) { + RootedId id(cx); + if (!ToId(cx, index, &id)) + return false; + return success.reportError(cx, obj, id); + } + return true; +} + +static bool +DeletePropertiesOrThrow(JSContext* cx, HandleObject obj, uint64_t len, uint64_t finalLength) +{ + if (obj->is<ArrayObject>() && + !obj->as<NativeObject>().isIndexed() && + !obj->as<NativeObject>().denseElementsAreFrozen()) + { + if (len <= UINT32_MAX) { + // Skip forward to the initialized elements of this array. + len = Min(uint32_t(len), obj->as<ArrayObject>().getDenseInitializedLength()); + } + } + + for (uint64_t k = len; k > finalLength; k--) { + if (!CheckForInterrupt(cx)) + return false; + + if (!DeletePropertyOrThrow(cx, obj, k - 1)) + return false; + } + return true; +} + +static bool +SetArrayLengthProperty(JSContext* cx, HandleArrayObject obj, HandleValue value) +{ + RootedId id(cx, NameToId(cx->names().length)); + ObjectOpResult result; + if (obj->lengthIsWritable()) { + if (!ArraySetLength(cx, obj, id, JSPROP_PERMANENT, value, result)) + return false; + } else { + MOZ_ALWAYS_TRUE(result.fail(JSMSG_READ_ONLY)); + } + return result.checkStrict(cx, obj, id); +} + +static bool +SetLengthProperty(JSContext* cx, HandleObject obj, uint64_t length) +{ + MOZ_ASSERT(length < uint64_t(DOUBLE_INTEGRAL_PRECISION_LIMIT)); + + RootedValue v(cx, NumberValue(length)); + if (obj->is<ArrayObject>()) + return SetArrayLengthProperty(cx, obj.as<ArrayObject>(), v); + return SetProperty(cx, obj, cx->names().length, v); +} + +bool +js::SetLengthProperty(JSContext* cx, HandleObject obj, uint32_t length) +{ + RootedValue v(cx, NumberValue(length)); + if (obj->is<ArrayObject>()) + return SetArrayLengthProperty(cx, obj.as<ArrayObject>(), v); + return SetProperty(cx, obj, cx->names().length, v); +} + +static bool +array_length_getter(JSContext* cx, HandleObject obj, HandleId id, MutableHandleValue vp) +{ + vp.setNumber(obj->as<ArrayObject>().length()); + return true; +} + +static bool +array_length_setter(JSContext* cx, HandleObject obj, HandleId id, HandleValue v, + ObjectOpResult& result) +{ + MOZ_ASSERT(id == NameToId(cx->names().length)); + + if (!obj->is<ArrayObject>()) { + // This array .length property was found on the prototype + // chain. Ideally the setter should not have been called, but since + // we're here, do an impression of SetPropertyByDefining. + return DefineDataProperty(cx, obj, id, v, JSPROP_ENUMERATE, result); + } + + HandleArrayObject arr = obj.as<ArrayObject>(); + MOZ_ASSERT(arr->lengthIsWritable(), + "setter shouldn't be called if property is non-writable"); + + return ArraySetLength(cx, arr, id, JSPROP_PERMANENT, v, result); +} + +struct ReverseIndexComparator +{ + bool operator()(const uint32_t& a, const uint32_t& b, bool* lessOrEqualp) { + MOZ_ASSERT(a != b, "how'd we get duplicate indexes?"); + *lessOrEqualp = b <= a; + return true; + } +}; + +static bool +MaybeInIteration(HandleObject obj, JSContext* cx) +{ + /* + * Don't optimize if the array might be in the midst of iteration. We + * rely on this to be able to safely move dense array elements around with + * just a memmove (see NativeObject::moveDenseArrayElements), without worrying + * about updating any in-progress enumerators for properties implicitly + * deleted if a hole is moved from one location to another location not yet + * visited. See bug 690622. + * + * Note that it's fine to optimize if |obj| is on the prototype of another + * object: SuppressDeletedProperty only suppresses properties deleted from + * the iterated object itself. + */ + + if (MOZ_LIKELY(!cx->compartment()->objectMaybeInIteration(obj))) + return false; + + ObjectGroup* group = JSObject::getGroup(cx, obj); + if (MOZ_UNLIKELY(!group)) { + cx->recoverFromOutOfMemory(); + return true; + } + + if (MOZ_UNLIKELY(group->hasAllFlags(OBJECT_FLAG_ITERATED))) + return true; + + return false; +} + +/* ES6 draft rev 34 (2015 Feb 20) 9.4.2.4 ArraySetLength */ +bool +js::ArraySetLength(JSContext* cx, Handle<ArrayObject*> arr, HandleId id, + unsigned attrs, HandleValue value, ObjectOpResult& result) +{ + MOZ_ASSERT(id == NameToId(cx->names().length)); + + if (!arr->maybeCopyElementsForWrite(cx)) + return false; + + // Step 1. + uint32_t newLen; + if (attrs & JSPROP_IGNORE_VALUE) { + MOZ_ASSERT(value.isUndefined()); + + // The spec has us calling OrdinaryDefineOwnProperty if + // Desc.[[Value]] is absent, but our implementation is so different that + // this is impossible. Instead, set newLen to the current length and + // proceed to step 9. + newLen = arr->length(); + } else { + // Step 2 is irrelevant in our implementation. + + // Step 3. + if (!ToUint32(cx, value, &newLen)) + return false; + + // Step 4. + double d; + if (!ToNumber(cx, value, &d)) + return false; + + // Step 5. + if (d != newLen) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BAD_ARRAY_LENGTH); + return false; + } + + // Steps 6-8 are irrelevant in our implementation. + } + + // Steps 9-11. + bool lengthIsWritable = arr->lengthIsWritable(); +#ifdef DEBUG + { + RootedShape lengthShape(cx, arr->lookupPure(id)); + MOZ_ASSERT(lengthShape); + MOZ_ASSERT(lengthShape->writable() == lengthIsWritable); + } +#endif + uint32_t oldLen = arr->length(); + + // Part of steps 1.a, 12.a, and 16: Fail if we're being asked to change + // enumerability or configurability, or otherwise break the object + // invariants. (ES6 checks these by calling OrdinaryDefineOwnProperty, but + // in SM, the array length property is hardly ordinary.) + if ((attrs & (JSPROP_PERMANENT | JSPROP_IGNORE_PERMANENT)) == 0 || + (attrs & (JSPROP_ENUMERATE | JSPROP_IGNORE_ENUMERATE)) == JSPROP_ENUMERATE || + (attrs & (JSPROP_GETTER | JSPROP_SETTER)) != 0 || + (!lengthIsWritable && (attrs & (JSPROP_READONLY | JSPROP_IGNORE_READONLY)) == 0)) + { + return result.fail(JSMSG_CANT_REDEFINE_PROP); + } + + // Steps 12-13 for arrays with non-writable length. + if (!lengthIsWritable) { + if (newLen == oldLen) + return result.succeed(); + + return result.fail(JSMSG_CANT_REDEFINE_ARRAY_LENGTH); + } + + // Step 19. + bool succeeded = true; + do { + // The initialized length and capacity of an array only need updating + // when non-hole elements are added or removed, which doesn't happen + // when array length stays the same or increases. + if (newLen >= oldLen) + break; + + // Attempt to propagate dense-element optimization tricks, if possible, + // and avoid the generic (and accordingly slow) deletion code below. + // We can only do this if there are only densely-indexed elements. + // Once there's a sparse indexed element, there's no good way to know, + // save by enumerating all the properties to find it. But we *have* to + // know in case that sparse indexed element is non-configurable, as + // that element must prevent any deletions below it. Bug 586842 should + // fix this inefficiency by moving indexed storage to be entirely + // separate from non-indexed storage. + // A second reason for this optimization to be invalid is an active + // for..in iteration over the array. Keys deleted before being reached + // during the iteration must not be visited, and suppressing them here + // would be too costly. + if (!arr->isIndexed() && !MaybeInIteration(arr, cx)) { + if (!arr->maybeCopyElementsForWrite(cx)) + return false; + + uint32_t oldCapacity = arr->getDenseCapacity(); + uint32_t oldInitializedLength = arr->getDenseInitializedLength(); + MOZ_ASSERT(oldCapacity >= oldInitializedLength); + if (oldInitializedLength > newLen) + arr->setDenseInitializedLength(newLen); + if (oldCapacity > newLen) + arr->shrinkElements(cx, newLen); + + // We've done the work of deleting any dense elements needing + // deletion, and there are no sparse elements. Thus we can skip + // straight to defining the length. + break; + } + + // Step 15. + // + // Attempt to delete all elements above the new length, from greatest + // to least. If any of these deletions fails, we're supposed to define + // the length to one greater than the index that couldn't be deleted, + // *with the property attributes specified*. This might convert the + // length to be not the value specified, yet non-writable. (You may be + // forgiven for thinking these are interesting semantics.) Example: + // + // var arr = + // Object.defineProperty([0, 1, 2, 3], 1, { writable: false }); + // Object.defineProperty(arr, "length", + // { value: 0, writable: false }); + // + // will convert |arr| to an array of non-writable length two, then + // throw a TypeError. + // + // We implement this behavior, in the relevant lops below, by setting + // |succeeded| to false. Then we exit the loop, define the length + // appropriately, and only then throw a TypeError, if necessary. + uint32_t gap = oldLen - newLen; + const uint32_t RemoveElementsFastLimit = 1 << 24; + if (gap < RemoveElementsFastLimit) { + // If we're removing a relatively small number of elements, just do + // it exactly by the spec. + while (newLen < oldLen) { + // Step 15a. + oldLen--; + + // Steps 15b-d. + ObjectOpResult deleteSucceeded; + if (!DeleteElement(cx, arr, oldLen, deleteSucceeded)) + return false; + if (!deleteSucceeded) { + newLen = oldLen + 1; + succeeded = false; + break; + } + } + } else { + // If we're removing a large number of elements from an array + // that's probably sparse, try a different tack. Get all the own + // property names, sift out the indexes in the deletion range into + // a vector, sort the vector greatest to least, then delete the + // indexes greatest to least using that vector. See bug 322135. + // + // This heuristic's kind of a huge guess -- "large number of + // elements" and "probably sparse" are completely unprincipled + // predictions. In the long run, bug 586842 will support the right + // fix: store sparse elements in a sorted data structure that + // permits fast in-reverse-order traversal and concurrent removals. + + Vector<uint32_t> indexes(cx); + { + AutoIdVector props(cx); + if (!GetPropertyKeys(cx, arr, JSITER_OWNONLY | JSITER_HIDDEN, &props)) + return false; + + for (size_t i = 0; i < props.length(); i++) { + if (!CheckForInterrupt(cx)) + return false; + + uint32_t index; + if (!IdIsIndex(props[i], &index)) + continue; + + if (index >= newLen && index < oldLen) { + if (!indexes.append(index)) + return false; + } + } + } + + uint32_t count = indexes.length(); + { + // We should use radix sort to be O(n), but this is uncommon + // enough that we'll punt til someone complains. + Vector<uint32_t> scratch(cx); + if (!scratch.resize(count)) + return false; + MOZ_ALWAYS_TRUE(MergeSort(indexes.begin(), count, scratch.begin(), + ReverseIndexComparator())); + } + + uint32_t index = UINT32_MAX; + for (uint32_t i = 0; i < count; i++) { + MOZ_ASSERT(indexes[i] < index, "indexes should never repeat"); + index = indexes[i]; + + // Steps 15b-d. + ObjectOpResult deleteSucceeded; + if (!DeleteElement(cx, arr, index, deleteSucceeded)) + return false; + if (!deleteSucceeded) { + newLen = index + 1; + succeeded = false; + break; + } + } + } + } while (false); + + // Update array length. Technically we should have been doing this + // throughout the loop, in step 19.d.iii. + arr->setLength(cx, newLen); + + // Step 20. + if (attrs & JSPROP_READONLY) { + // Yes, we totally drop a non-stub getter/setter from a defineProperty + // API call on the floor here. Given that getter/setter will go away in + // the long run, with accessors replacing them both internally and at the + // API level, just run with this. + RootedShape lengthShape(cx, arr->lookup(cx, id)); + if (!NativeObject::changeProperty(cx, arr, lengthShape, + lengthShape->attributes() | JSPROP_READONLY, + array_length_getter, array_length_setter)) + { + return false; + } + } + + // All operations past here until the |!succeeded| code must be infallible, + // so that all element fields remain properly synchronized. + + // Trim the initialized length, if needed, to preserve the <= length + // invariant. (Capacity was already reduced during element deletion, if + // necessary.) + ObjectElements* header = arr->getElementsHeader(); + header->initializedLength = Min(header->initializedLength, newLen); + + if (attrs & JSPROP_READONLY) + arr->setNonWritableLength(cx); + + if (!succeeded) + return result.fail(JSMSG_CANT_TRUNCATE_ARRAY); + + return result.succeed(); +} + +bool +js::WouldDefinePastNonwritableLength(HandleNativeObject obj, uint32_t index) +{ + if (!obj->is<ArrayObject>()) + return false; + + ArrayObject* arr = &obj->as<ArrayObject>(); + return !arr->lengthIsWritable() && index >= arr->length(); +} + +static bool +array_addProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v) +{ + ArrayObject* arr = &obj->as<ArrayObject>(); + + uint32_t index; + if (!IdIsIndex(id, &index)) + return true; + + uint32_t length = arr->length(); + if (index >= length) { + MOZ_ASSERT(arr->lengthIsWritable(), + "how'd this element get added if length is non-writable?"); + arr->setLength(cx, index + 1); + } + return true; +} + +static inline bool +ObjectMayHaveExtraIndexedOwnProperties(JSObject* obj) +{ + if (!obj->isNative()) + return true; + + if (obj->as<NativeObject>().isIndexed()) + return true; + + if (obj->is<TypedArrayObject>()) + return true; + + return ClassMayResolveId(*obj->runtimeFromAnyThread()->commonNames, + obj->getClass(), INT_TO_JSID(0), obj); +} + +/* + * Whether obj may have indexed properties anywhere besides its dense + * elements. This includes other indexed properties in its shape hierarchy, and + * indexed properties or elements along its prototype chain. + */ +static bool +ObjectMayHaveExtraIndexedProperties(JSObject* obj) +{ + MOZ_ASSERT_IF(obj->hasDynamicPrototype(), !obj->isNative()); + + if (ObjectMayHaveExtraIndexedOwnProperties(obj)) + return true; + + do { + MOZ_ASSERT(obj->hasStaticPrototype(), + "dynamic-prototype objects must be non-native, ergo must " + "have failed ObjectMayHaveExtraIndexedOwnProperties"); + + obj = obj->staticPrototype(); + if (!obj) + return false; // no extra indexed properties found + + if (ObjectMayHaveExtraIndexedOwnProperties(obj)) + return true; + if (obj->as<NativeObject>().getDenseInitializedLength() != 0) + return true; + } while (true); +} + +static bool +AddLengthProperty(JSContext* cx, HandleArrayObject obj) +{ + /* + * Add the 'length' property for a newly created array, + * and update the elements to be an empty array owned by the object. + * The shared emptyObjectElements singleton cannot be used for slow arrays, + * as accesses to 'length' will use the elements header. + */ + + RootedId lengthId(cx, NameToId(cx->names().length)); + MOZ_ASSERT(!obj->lookup(cx, lengthId)); + + return NativeObject::addAccessorProperty(cx, obj, lengthId, + array_length_getter, array_length_setter, + JSPROP_PERMANENT | JSPROP_SHADOWABLE); +} + +static bool +IsArrayConstructor(const JSObject* obj) +{ + // This must only return true if v is *the* Array constructor for the + // current compartment; we rely on the fact that any other Array + // constructor would be represented as a wrapper. + return obj->is<JSFunction>() && + obj->as<JSFunction>().isNative() && + obj->as<JSFunction>().native() == ArrayConstructor; +} + +static bool +IsArrayConstructor(const Value& v) +{ + return v.isObject() && IsArrayConstructor(&v.toObject()); +} + +bool +js::IsWrappedArrayConstructor(JSContext* cx, const Value& v, bool* result) +{ + if (!v.isObject()) { + *result = false; + return true; + } + if (v.toObject().is<WrapperObject>()) { + JSObject* obj = CheckedUnwrap(&v.toObject()); + if (!obj) { + ReportAccessDenied(cx); + return false; + } + + *result = IsArrayConstructor(obj); + } else { + *result = false; + } + return true; +} + +static MOZ_ALWAYS_INLINE bool +IsArraySpecies(JSContext* cx, HandleObject origArray) +{ + if (MOZ_UNLIKELY(origArray->is<ProxyObject>())) { + if (origArray->getClass()->isDOMClass()) { +#ifdef DEBUG + // We assume DOM proxies never return true for IsArray. + IsArrayAnswer answer; + MOZ_ASSERT(Proxy::isArray(cx, origArray, &answer)); + MOZ_ASSERT(answer == IsArrayAnswer::NotArray); +#endif + return true; + } + return false; + } + + // 9.4.2.3 Step 4. Non-array objects always use the default constructor. + if (!origArray->is<ArrayObject>()) + return true; + + if (cx->compartment()->arraySpeciesLookup.tryOptimizeArray(cx, &origArray->as<ArrayObject>())) + return true; + + Value ctor; + if (!GetPropertyPure(cx, origArray, NameToId(cx->names().constructor), &ctor)) + return false; + + if (!IsArrayConstructor(ctor)) + return ctor.isUndefined(); + + jsid speciesId = SYMBOL_TO_JSID(cx->wellKnownSymbols().species); + JSFunction* getter; + if (!GetGetterPure(cx, &ctor.toObject(), speciesId, &getter)) + return false; + + if (!getter) + return false; + + return IsSelfHostedFunctionWithName(getter, cx->names().ArraySpecies); +} + +static bool +ArraySpeciesCreate(JSContext* cx, HandleObject origArray, uint64_t length, MutableHandleObject arr) +{ + MOZ_ASSERT(length < DOUBLE_INTEGRAL_PRECISION_LIMIT); + + FixedInvokeArgs<2> args(cx); + + args[0].setObject(*origArray); + args[1].set(NumberValue(length)); + + RootedValue rval(cx); + if (!CallSelfHostedFunction(cx, cx->names().ArraySpeciesCreate, UndefinedHandleValue, args, + &rval)) + { + return false; + } + + MOZ_ASSERT(rval.isObject()); + arr.set(&rval.toObject()); + return true; +} + +static bool +array_toSource(JSContext* cx, unsigned argc, Value* vp) +{ + if (!CheckRecursionLimit(cx)) + return false; + + CallArgs args = CallArgsFromVp(argc, vp); + + if (!args.thisv().isObject()) { + ReportIncompatible(cx, args); + return false; + } + + Rooted<JSObject*> obj(cx, &args.thisv().toObject()); + RootedValue elt(cx); + + AutoCycleDetector detector(cx, obj); + if (!detector.init()) + return false; + + StringBuffer sb(cx); + + if (detector.foundCycle()) { + if (!sb.append("[]")) + return false; + goto make_string; + } + + if (!sb.append('[')) + return false; + + uint64_t length; + if (!GetLengthProperty(cx, obj, &length)) + return false; + + for (uint64_t index = 0; index < length; index++) { + bool hole; + if (!CheckForInterrupt(cx) || + !HasAndGetElement(cx, obj, index, &hole, &elt)) { + return false; + } + + /* Get element's character string. */ + JSString* str; + if (hole) { + str = cx->runtime()->emptyString; + } else { + str = ValueToSource(cx, elt); + if (!str) + return false; + } + + /* Append element to buffer. */ + if (!sb.append(str)) + return false; + if (index + 1 != length) { + if (!sb.append(", ")) + return false; + } else if (hole) { + if (!sb.append(',')) + return false; + } + } + + /* Finalize the buffer. */ + if (!sb.append(']')) + return false; + + make_string: + JSString* str = sb.finishString(); + if (!str) + return false; + + args.rval().setString(str); + return true; +} + +struct EmptySeparatorOp +{ + bool operator()(JSContext*, StringBuffer& sb) { return true; } +}; + +template <typename CharT> +struct CharSeparatorOp +{ + const CharT sep; + explicit CharSeparatorOp(CharT sep) : sep(sep) {} + bool operator()(JSContext*, StringBuffer& sb) { return sb.append(sep); } +}; + +struct StringSeparatorOp +{ + HandleLinearString sep; + + explicit StringSeparatorOp(HandleLinearString sep) : sep(sep) {} + + bool operator()(JSContext* cx, StringBuffer& sb) { + return sb.append(sep); + } +}; + +template <typename SeparatorOp> +static bool +ArrayJoinDenseKernel(JSContext* cx, SeparatorOp sepOp, HandleNativeObject obj, uint64_t length, + StringBuffer& sb, uint32_t* numProcessed) +{ + // This loop handles all elements up to initializedLength. If + // length > initLength we rely on the second loop to add the + // other elements. + MOZ_ASSERT(*numProcessed == 0); + uint64_t initLength = Min<uint64_t>(obj->getDenseInitializedLength(), + length); + MOZ_ASSERT(initLength <= UINT32_MAX, "initialized length shouldn't exceed UINT32_MAX"); + uint32_t initLengthClamped = uint32_t(initLength); + while (*numProcessed < initLengthClamped) { + if (!CheckForInterrupt(cx)) + return false; + + // Step 7.b. + Value elem = obj->getDenseElement(*numProcessed); + + // Steps 7.c-d. + if (elem.isString()) { + if (!sb.append(elem.toString())) + return false; + } else if (elem.isNumber()) { + if (!NumberValueToStringBuffer(cx, elem, sb)) + return false; + } else if (elem.isBoolean()) { + if (!BooleanToStringBuffer(elem.toBoolean(), sb)) + return false; + } else if (elem.isObject() || elem.isSymbol()) { + /* + * Object stringifying could modify the initialized length or make + * the array sparse. Delegate it to a separate loop to keep this + * one tight. + * + * Symbol stringifying is a TypeError, so into the slow path + * with those as well. + */ + break; + } else { + MOZ_ASSERT(elem.isMagic(JS_ELEMENTS_HOLE) || elem.isNullOrUndefined()); + } + + // Steps 7.a, 7.e. + if (++(*numProcessed) != length && !sepOp(cx, sb)) + return false; + } + + return true; +} + +template <typename SeparatorOp> +static bool +ArrayJoinKernel(JSContext* cx, SeparatorOp sepOp, HandleObject obj, uint64_t length, + StringBuffer& sb) +{ + // Step 6. + uint32_t numProcessed = 0; + + if (IsPackedArrayOrNoExtraIndexedProperties(obj, length)) { + if (!ArrayJoinDenseKernel<SeparatorOp>(cx, sepOp, obj.as<NativeObject>(), length, sb, + &numProcessed)) + { + return false; + } + } + + // Step 7. + if (numProcessed != length) { + RootedValue v(cx); + for (uint64_t i = numProcessed; i < length; ) { + if (!CheckForInterrupt(cx)) + return false; + + // Step 7.b. + if (!GetArrayElement(cx, obj, i, &v)) + return false; + + // Steps 7.c-d. + if (!v.isNullOrUndefined()) { + if (!ValueToStringBuffer(cx, v, sb)) + return false; + } + + // Steps 7.a, 7.e. + if (++i != length && !sepOp(cx, sb)) + return false; + } + } + + return true; +} + +// ES2017 draft rev 1b0184bc17fc09a8ddcf4aeec9b6d9fcac4eafce +// 22.1.3.13 Array.prototype.join ( separator ) +bool +js::array_join(JSContext* cx, unsigned argc, Value* vp) +{ + if (!CheckRecursionLimit(cx)) + return false; + + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.join"); + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1. + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + AutoCycleDetector detector(cx, obj); + if (!detector.init()) + return false; + + if (detector.foundCycle()) { + args.rval().setString(cx->names().empty); + return true; + } + + // Step 2. + uint64_t length; + if (!GetLengthProperty(cx, obj, &length)) + return false; + + // Steps 3-4. + RootedLinearString sepstr(cx); + if (args.hasDefined(0)) { + JSString *s = ToString<CanGC>(cx, args[0]); + if (!s) + return false; + sepstr = s->ensureLinear(cx); + if (!sepstr) + return false; + } else { + sepstr = cx->names().comma; + } + + // Steps 5-8 (When the length is zero, directly return the empty string). + if (length == 0) { + args.rval().setString(cx->emptyString()); + return true; + } + + // An optimized version of a special case of steps 5-8: when length==1 and + // the 0th element is a string, ToString() of that element is a no-op and + // so it can be immediately returned as the result. + if (length == 1 && obj->isNative()) { + NativeObject* nobj = &obj->as<NativeObject>(); + if (nobj->getDenseInitializedLength() == 1) { + Value elem0 = nobj->getDenseElement(0); + if (elem0.isString()) { + args.rval().set(elem0); + return true; + } + } + } + + // Step 5. + StringBuffer sb(cx); + if (sepstr->hasTwoByteChars() && !sb.ensureTwoByteChars()) + return false; + + // The separator will be added |length - 1| times, reserve space for that + // so that we don't have to unnecessarily grow the buffer. + size_t seplen = sepstr->length(); + if (seplen > 0) { + if (length > UINT32_MAX) { + ReportAllocationOverflow(cx); + return false; + } + CheckedInt<uint32_t> res = CheckedInt<uint32_t>(seplen) * (uint32_t(length) - 1); + if (!res.isValid()) { + ReportAllocationOverflow(cx); + return false; + } + + if (!sb.reserve(res.value())) + return false; + } + + // Various optimized versions of steps 6-7. + if (seplen == 0) { + EmptySeparatorOp op; + if (!ArrayJoinKernel(cx, op, obj, length, sb)) + return false; + } else if (seplen == 1) { + char16_t c = sepstr->latin1OrTwoByteChar(0); + if (c <= JSString::MAX_LATIN1_CHAR) { + CharSeparatorOp<Latin1Char> op(c); + if (!ArrayJoinKernel(cx, op, obj, length, sb)) + return false; + } else { + CharSeparatorOp<char16_t> op(c); + if (!ArrayJoinKernel(cx, op, obj, length, sb)) + return false; + } + } else { + StringSeparatorOp op(sepstr); + if (!ArrayJoinKernel(cx, op, obj, length, sb)) + return false; + } + + // Step 8. + JSString* str = sb.finishString(); + if (!str) + return false; + + args.rval().setString(str); + return true; +} + +// ES2017 draft rev f8a9be8ea4bd97237d176907a1e3080dce20c68f +// 22.1.3.27 Array.prototype.toLocaleString ([ reserved1 [ , reserved2 ] ]) +// ES2017 Intl draft rev 78bbe7d1095f5ff3760ac4017ed366026e4cb276 +// 13.4.1 Array.prototype.toLocaleString ([ locales [ , options ]]) +static bool +array_toLocaleString(JSContext* cx, unsigned argc, Value* vp) +{ + if (!CheckRecursionLimit(cx)) + return false; + + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1 + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + // Avoid calling into self-hosted code if the array is empty. + if (obj->is<ArrayObject>() && obj->as<ArrayObject>().length() == 0) { + args.rval().setString(cx->names().empty); + return true; + } + + AutoCycleDetector detector(cx, obj); + if (!detector.init()) + return false; + + if (detector.foundCycle()) { + args.rval().setString(cx->names().empty); + return true; + } + + FixedInvokeArgs<2> args2(cx); + + args2[0].set(args.get(0)); + args2[1].set(args.get(1)); + + // Steps 2-10. + RootedValue thisv(cx, ObjectValue(*obj)); + return CallSelfHostedFunction(cx, cx->names().ArrayToLocaleString, thisv, args2, args.rval()); +} + +/* vector must point to rooted memory. */ +static bool +SetArrayElements(JSContext* cx, HandleObject obj, uint64_t start, + uint32_t count, const Value* vector, + ShouldUpdateTypes updateTypes = ShouldUpdateTypes::Update) +{ + MOZ_ASSERT(count <= MAX_ARRAY_INDEX); + MOZ_ASSERT(start + count < uint64_t(DOUBLE_INTEGRAL_PRECISION_LIMIT)); + + if (count == 0) + return true; + + if (!ObjectMayHaveExtraIndexedProperties(obj) && start <= UINT32_MAX) { + NativeObject* nobj = &obj->as<NativeObject>(); + DenseElementResult result = nobj->setOrExtendDenseElements(cx, uint32_t(start), vector, + count, updateTypes); + if (result != DenseElementResult::Incomplete) + return result == DenseElementResult::Success; + } + + RootedId id(cx); + const Value* end = vector + count; + while (vector < end) { + if (!CheckForInterrupt(cx)) + return false; + + if (!ToId(cx, start++, &id)) + return false; + + if (!SetProperty(cx, obj, id, HandleValue::fromMarkedLocation(vector++))) + return false; + } + + return true; +} + +static DenseElementResult +ArrayReverseDenseKernel(JSContext* cx, HandleNativeObject obj, uint32_t length) +{ + MOZ_ASSERT(length > 1); + + // If there are no elements, we're done. + if (obj->getDenseInitializedLength() == 0) + return DenseElementResult::Success; + + if (obj->denseElementsAreFrozen()) + return DenseElementResult::Incomplete; + + if (!IsPackedArray(obj)) { + /* + * It's actually surprisingly complicated to reverse an array due + * to the orthogonality of array length and array capacity while + * handling leading and trailing holes correctly. Reversing seems + * less likely to be a common operation than other array + * mass-mutation methods, so for now just take a probably-small + * memory hit (in the absence of too many holes in the array at + * its start) and ensure that the capacity is sufficient to hold + * all the elements in the array if it were full. + */ + DenseElementResult result = obj->ensureDenseElements(cx, length, 0); + if (result != DenseElementResult::Success) + return result; + + /* Fill out the array's initialized length to its proper length. */ + obj->ensureDenseInitializedLength(cx, length, 0); + } else { + if (!obj->maybeCopyElementsForWrite(cx)) + return DenseElementResult::Failure; + } + + if (!MaybeInIteration(obj, cx) && !cx->zone()->needsIncrementalBarrier()) { + obj->reverseDenseElementsNoPreBarrier(length); + return DenseElementResult::Success; + } + + RootedValue origlo(cx), orighi(cx); + + uint32_t lo = 0, hi = length - 1; + for (; lo < hi; lo++, hi--) { + origlo = obj->getDenseElement(lo); + orighi = obj->getDenseElement(hi); + obj->setDenseElement(lo, orighi); + if (orighi.isMagic(JS_ELEMENTS_HOLE) && + !SuppressDeletedProperty(cx, obj, INT_TO_JSID(lo))) + { + return DenseElementResult::Failure; + } + obj->setDenseElement(hi, origlo); + if (origlo.isMagic(JS_ELEMENTS_HOLE) && + !SuppressDeletedProperty(cx, obj, INT_TO_JSID(hi))) + { + return DenseElementResult::Failure; + } + } + + return DenseElementResult::Success; +} + +// ES2017 draft rev 1b0184bc17fc09a8ddcf4aeec9b6d9fcac4eafce +// 22.1.3.21 Array.prototype.reverse ( ) +bool +js::array_reverse(JSContext* cx, unsigned argc, Value* vp) +{ + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.reverse"); + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1. + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + // Step 2. + uint64_t len; + if (!GetLengthProperty(cx, obj, &len)) + return false; + + // An empty array or an array with length 1 is already reversed. + if (len <= 1) { + args.rval().setObject(*obj); + return true; + } + + if (IsPackedArrayOrNoExtraIndexedProperties(obj, len) && len <= UINT32_MAX) { + DenseElementResult result = + ArrayReverseDenseKernel(cx, obj.as<NativeObject>(), uint32_t(len)); + if (result != DenseElementResult::Incomplete) { + /* + * Per ECMA-262, don't update the length of the array, even if the new + * array has trailing holes (and thus the original array began with + * holes). + */ + args.rval().setObject(*obj); + return result == DenseElementResult::Success; + } + } + + // Steps 3-5. + RootedValue lowval(cx), hival(cx); + for (uint64_t i = 0, half = len / 2; i < half; i++) { + bool hole, hole2; + if (!CheckForInterrupt(cx) || + !HasAndGetElement(cx, obj, i, &hole, &lowval) || + !HasAndGetElement(cx, obj, len - i - 1, &hole2, &hival)) + { + return false; + } + + if (!hole && !hole2) { + if (!SetArrayElement(cx, obj, i, hival)) + return false; + if (!SetArrayElement(cx, obj, len - i - 1, lowval)) + return false; + } else if (hole && !hole2) { + if (!SetArrayElement(cx, obj, i, hival)) + return false; + if (!DeletePropertyOrThrow(cx, obj, len - i - 1)) + return false; + } else if (!hole && hole2) { + if (!DeletePropertyOrThrow(cx, obj, i)) + return false; + if (!SetArrayElement(cx, obj, len - i - 1, lowval)) + return false; + } else { + // No action required. + } + } + + // Step 6. + args.rval().setObject(*obj); + return true; +} + +static inline bool +CompareStringValues(JSContext* cx, const Value& a, const Value& b, bool* lessOrEqualp) +{ + if (!CheckForInterrupt(cx)) + return false; + + JSString* astr = a.toString(); + JSString* bstr = b.toString(); + int32_t result; + if (!CompareStrings(cx, astr, bstr, &result)) + return false; + + *lessOrEqualp = (result <= 0); + return true; +} + +static const uint64_t powersOf10[] = { + 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000, 1000000000000ULL +}; + +static inline unsigned +NumDigitsBase10(uint32_t n) +{ + /* + * This is just floor_log10(n) + 1 + * Algorithm taken from + * http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog10 + */ + uint32_t log2 = CeilingLog2(n); + uint32_t t = log2 * 1233 >> 12; + return t - (n < powersOf10[t]) + 1; +} + +static inline bool +CompareLexicographicInt32(const Value& a, const Value& b, bool* lessOrEqualp) +{ + int32_t aint = a.toInt32(); + int32_t bint = b.toInt32(); + + /* + * If both numbers are equal ... trivial + * If only one of both is negative --> arithmetic comparison as char code + * of '-' is always less than any other digit + * If both numbers are negative convert them to positive and continue + * handling ... + */ + if (aint == bint) { + *lessOrEqualp = true; + } else if ((aint < 0) && (bint >= 0)) { + *lessOrEqualp = true; + } else if ((aint >= 0) && (bint < 0)) { + *lessOrEqualp = false; + } else { + uint32_t auint = Abs(aint); + uint32_t buint = Abs(bint); + + /* + * ... get number of digits of both integers. + * If they have the same number of digits --> arithmetic comparison. + * If digits_a > digits_b: a < b*10e(digits_a - digits_b). + * If digits_b > digits_a: a*10e(digits_b - digits_a) <= b. + */ + unsigned digitsa = NumDigitsBase10(auint); + unsigned digitsb = NumDigitsBase10(buint); + if (digitsa == digitsb) { + *lessOrEqualp = (auint <= buint); + } else if (digitsa > digitsb) { + MOZ_ASSERT((digitsa - digitsb) < ArrayLength(powersOf10)); + *lessOrEqualp = (uint64_t(auint) < uint64_t(buint) * powersOf10[digitsa - digitsb]); + } else { /* if (digitsb > digitsa) */ + MOZ_ASSERT((digitsb - digitsa) < ArrayLength(powersOf10)); + *lessOrEqualp = (uint64_t(auint) * powersOf10[digitsb - digitsa] <= uint64_t(buint)); + } + } + + return true; +} + +template <typename Char1, typename Char2> +static inline bool +CompareSubStringValues(JSContext* cx, const Char1* s1, size_t len1, const Char2* s2, size_t len2, + bool* lessOrEqualp) +{ + if (!CheckForInterrupt(cx)) + return false; + + if (!s1 || !s2) + return false; + + int32_t result = CompareChars(s1, len1, s2, len2); + *lessOrEqualp = (result <= 0); + return true; +} + +namespace { + +struct SortComparatorStrings +{ + JSContext* const cx; + + explicit SortComparatorStrings(JSContext* cx) + : cx(cx) {} + + bool operator()(const Value& a, const Value& b, bool* lessOrEqualp) { + return CompareStringValues(cx, a, b, lessOrEqualp); + } +}; + +struct SortComparatorLexicographicInt32 +{ + bool operator()(const Value& a, const Value& b, bool* lessOrEqualp) { + return CompareLexicographicInt32(a, b, lessOrEqualp); + } +}; + +struct StringifiedElement +{ + size_t charsBegin; + size_t charsEnd; + size_t elementIndex; +}; + +struct SortComparatorStringifiedElements +{ + JSContext* const cx; + const StringBuffer& sb; + + SortComparatorStringifiedElements(JSContext* cx, const StringBuffer& sb) + : cx(cx), sb(sb) {} + + bool operator()(const StringifiedElement& a, const StringifiedElement& b, bool* lessOrEqualp) { + size_t lenA = a.charsEnd - a.charsBegin; + size_t lenB = b.charsEnd - b.charsBegin; + + if (sb.isUnderlyingBufferLatin1()) { + return CompareSubStringValues(cx, sb.rawLatin1Begin() + a.charsBegin, lenA, + sb.rawLatin1Begin() + b.charsBegin, lenB, + lessOrEqualp); + } + + return CompareSubStringValues(cx, sb.rawTwoByteBegin() + a.charsBegin, lenA, + sb.rawTwoByteBegin() + b.charsBegin, lenB, + lessOrEqualp); + } +}; + +struct NumericElement +{ + double dv; + size_t elementIndex; +}; + +static bool +ComparatorNumericLeftMinusRight(const NumericElement& a, const NumericElement& b, + bool* lessOrEqualp) +{ + *lessOrEqualp = (a.dv <= b.dv); + return true; +} + +static bool +ComparatorNumericRightMinusLeft(const NumericElement& a, const NumericElement& b, + bool* lessOrEqualp) +{ + *lessOrEqualp = (b.dv <= a.dv); + return true; +} + +typedef bool (*ComparatorNumeric)(const NumericElement& a, const NumericElement& b, + bool* lessOrEqualp); + +static const ComparatorNumeric SortComparatorNumerics[] = { + nullptr, + nullptr, + ComparatorNumericLeftMinusRight, + ComparatorNumericRightMinusLeft +}; + +static bool +ComparatorInt32LeftMinusRight(const Value& a, const Value& b, bool* lessOrEqualp) +{ + *lessOrEqualp = (a.toInt32() <= b.toInt32()); + return true; +} + +static bool +ComparatorInt32RightMinusLeft(const Value& a, const Value& b, bool* lessOrEqualp) +{ + *lessOrEqualp = (b.toInt32() <= a.toInt32()); + return true; +} + +typedef bool (*ComparatorInt32)(const Value& a, const Value& b, bool* lessOrEqualp); + +static const ComparatorInt32 SortComparatorInt32s[] = { + nullptr, + nullptr, + ComparatorInt32LeftMinusRight, + ComparatorInt32RightMinusLeft +}; + +// Note: Values for this enum must match up with SortComparatorNumerics +// and SortComparatorInt32s. +enum ComparatorMatchResult { + Match_Failure = 0, + Match_None, + Match_LeftMinusRight, + Match_RightMinusLeft +}; + +} // namespace + + +/* + * Specialize behavior for comparator functions with particular common bytecode + * patterns: namely, |return x - y| and |return y - x|. + */ +static ComparatorMatchResult +MatchNumericComparator(JSContext* cx, JSObject* obj) +{ + if (!obj->is<JSFunction>()) + return Match_None; + + RootedFunction fun(cx, &obj->as<JSFunction>()); + if (!fun->isInterpreted() || fun->isClassConstructor()) + return Match_None; + + JSScript* script = JSFunction::getOrCreateScript(cx, fun); + if (!script) + return Match_Failure; + + jsbytecode* pc = script->code(); + + uint16_t arg0, arg1; + if (JSOp(*pc) != JSOP_GETARG) + return Match_None; + arg0 = GET_ARGNO(pc); + pc += JSOP_GETARG_LENGTH; + + if (JSOp(*pc) != JSOP_GETARG) + return Match_None; + arg1 = GET_ARGNO(pc); + pc += JSOP_GETARG_LENGTH; + + if (JSOp(*pc) != JSOP_SUB) + return Match_None; + pc += JSOP_SUB_LENGTH; + + if (JSOp(*pc) != JSOP_RETURN) + return Match_None; + + if (arg0 == 0 && arg1 == 1) + return Match_LeftMinusRight; + + if (arg0 == 1 && arg1 == 0) + return Match_RightMinusLeft; + + return Match_None; +} + +template <typename K, typename C> +static inline bool +MergeSortByKey(K keys, size_t len, K scratch, C comparator, MutableHandle<GCVector<Value>> vec) +{ + MOZ_ASSERT(vec.length() >= len); + + /* Sort keys. */ + if (!MergeSort(keys, len, scratch, comparator)) + return false; + + /* + * Reorder vec by keys in-place, going element by element. When an out-of- + * place element is encountered, move that element to its proper position, + * displacing whatever element was at *that* point to its proper position, + * and so on until an element must be moved to the current position. + * + * At each outer iteration all elements up to |i| are sorted. If + * necessary each inner iteration moves some number of unsorted elements + * (including |i|) directly to sorted position. Thus on completion |*vec| + * is sorted, and out-of-position elements have moved once. Complexity is + * Θ(len) + O(len) == O(2*len), with each element visited at most twice. + */ + for (size_t i = 0; i < len; i++) { + size_t j = keys[i].elementIndex; + if (i == j) + continue; // fixed point + + MOZ_ASSERT(j > i, "Everything less than |i| should be in the right place!"); + Value tv = vec[j]; + do { + size_t k = keys[j].elementIndex; + keys[j].elementIndex = j; + vec[j].set(vec[k]); + j = k; + } while (j != i); + + // We could assert the loop invariant that |i == keys[i].elementIndex| + // here if we synced |keys[i].elementIndex|. But doing so would render + // the assertion vacuous, so don't bother, even in debug builds. + vec[i].set(tv); + } + + return true; +} + +/* + * Sort Values as strings. + * + * To minimize #conversions, SortLexicographically() first converts all Values + * to strings at once, then sorts the elements by these cached strings. + */ +static bool +SortLexicographically(JSContext* cx, MutableHandle<GCVector<Value>> vec, size_t len) +{ + MOZ_ASSERT(vec.length() >= len); + + StringBuffer sb(cx); + Vector<StringifiedElement, 0, TempAllocPolicy> strElements(cx); + + /* MergeSort uses the upper half as scratch space. */ + if (!strElements.resize(2 * len)) + return false; + + /* Convert Values to strings. */ + size_t cursor = 0; + for (size_t i = 0; i < len; i++) { + if (!CheckForInterrupt(cx)) + return false; + + if (!ValueToStringBuffer(cx, vec[i], sb)) + return false; + + strElements[i] = { cursor, sb.length(), i }; + cursor = sb.length(); + } + + /* Sort Values in vec alphabetically. */ + return MergeSortByKey(strElements.begin(), len, strElements.begin() + len, + SortComparatorStringifiedElements(cx, sb), vec); +} + +/* + * Sort Values as numbers. + * + * To minimize #conversions, SortNumerically first converts all Values to + * numerics at once, then sorts the elements by these cached numerics. + */ +static bool +SortNumerically(JSContext* cx, MutableHandle<GCVector<Value>> vec, size_t len, + ComparatorMatchResult comp) +{ + MOZ_ASSERT(vec.length() >= len); + + Vector<NumericElement, 0, TempAllocPolicy> numElements(cx); + + /* MergeSort uses the upper half as scratch space. */ + if (!numElements.resize(2 * len)) + return false; + + /* Convert Values to numerics. */ + for (size_t i = 0; i < len; i++) { + if (!CheckForInterrupt(cx)) + return false; + + double dv; + if (!ToNumber(cx, vec[i], &dv)) + return false; + + numElements[i] = { dv, i }; + } + + /* Sort Values in vec numerically. */ + return MergeSortByKey(numElements.begin(), len, numElements.begin() + len, + SortComparatorNumerics[comp], vec); +} + +static bool +FillWithUndefined(JSContext* cx, HandleObject obj, uint32_t start, uint32_t count) +{ + MOZ_ASSERT(start < start + count, "count > 0 and start + count doesn't overflow"); + + do { + if (ObjectMayHaveExtraIndexedProperties(obj)) + break; + + NativeObject* nobj = &obj->as<NativeObject>(); + if (nobj->denseElementsAreFrozen()) + break; + + if (obj->is<ArrayObject>() && + !obj->as<ArrayObject>().lengthIsWritable() && + start + count >= obj->as<ArrayObject>().length()) + { + break; + } + + DenseElementResult result = nobj->ensureDenseElements(cx, start, count); + if (result != DenseElementResult::Success) { + if (result == DenseElementResult::Failure) + return false; + MOZ_ASSERT(result == DenseElementResult::Incomplete); + break; + } + + if (obj->is<ArrayObject>() && start + count >= obj->as<ArrayObject>().length()) + obj->as<ArrayObject>().setLengthInt32(start + count); + + for (uint32_t i = 0; i < count; i++) + nobj->setDenseElementWithType(cx, start + i, UndefinedHandleValue); + + return true; + } while (false); + + for (uint32_t i = 0; i < count; i++) { + if (!CheckForInterrupt(cx) || !SetArrayElement(cx, obj, start + i, UndefinedHandleValue)) + return false; + } + + return true; +} + +bool +js::intrinsic_ArrayNativeSort(JSContext* cx, unsigned argc, Value* vp) +{ + // This function is called from the self-hosted Array.prototype.sort + // implementation. It returns |true| if the array was sorted, otherwise it + // returns |false| to notify the self-hosted code to perform the sorting. + CallArgs args = CallArgsFromVp(argc, vp); + MOZ_ASSERT(args.length() == 1); + + HandleValue fval = args[0]; + MOZ_ASSERT(fval.isUndefined() || IsCallable(fval)); + + ComparatorMatchResult comp; + if (fval.isObject()) { + comp = MatchNumericComparator(cx, &fval.toObject()); + if (comp == Match_Failure) + return false; + + if (comp == Match_None) { + // Non-optimized user supplied comparators perform much better when + // called from within a self-hosted sorting function. + args.rval().setBoolean(false); + return true; + } + } else { + comp = Match_None; + } + + RootedObject obj(cx, &args.thisv().toObject()); + + uint64_t length; + if (!GetLengthProperty(cx, obj, &length)) + return false; + if (length < 2) { + /* [] and [a] remain unchanged when sorted. */ + args.rval().setBoolean(true); + return true; + } + + if (length > UINT32_MAX) { + ReportAllocationOverflow(cx); + return false; + } + uint32_t len = uint32_t(length); + + /* + * We need a temporary array of 2 * len Value to hold the array elements + * and the scratch space for merge sort. Check that its size does not + * overflow size_t, which would allow for indexing beyond the end of the + * malloc'd vector. + */ +#if JS_BITS_PER_WORD == 32 + if (size_t(len) > size_t(-1) / (2 * sizeof(Value))) { + ReportAllocationOverflow(cx); + return false; + } +#endif + + size_t n, undefs; + { + Rooted<GCVector<Value>> vec(cx, GCVector<Value>(cx)); + if (!vec.reserve(2 * size_t(len))) + return false; + + /* + * By ECMA 262, 15.4.4.11, a property that does not exist (which we + * call a "hole") is always greater than an existing property with + * value undefined and that is always greater than any other property. + * Thus to sort holes and undefs we simply count them, sort the rest + * of elements, append undefs after them and then make holes after + * undefs. + */ + undefs = 0; + bool allStrings = true; + bool allInts = true; + bool extraIndexed; + RootedValue v(cx); + if (IsPackedArray(obj)) { + HandleArrayObject array = obj.as<ArrayObject>(); + extraIndexed = false; + + for (uint32_t i = 0; i < len; i++) { + if (!CheckForInterrupt(cx)) + return false; + + v.set(array->getDenseElement(i)); + MOZ_ASSERT(!v.isMagic(JS_ELEMENTS_HOLE)); + if (v.isUndefined()) { + ++undefs; + continue; + } + vec.infallibleAppend(v); + allStrings = allStrings && v.isString(); + allInts = allInts && v.isInt32(); + } + } else { + extraIndexed = ObjectMayHaveExtraIndexedProperties(obj); + + for (uint32_t i = 0; i < len; i++) { + if (!CheckForInterrupt(cx)) + return false; + + bool hole; + if (!HasAndGetElement(cx, obj, i, &hole, &v)) + return false; + if (hole) + continue; + if (v.isUndefined()) { + ++undefs; + continue; + } + vec.infallibleAppend(v); + allStrings = allStrings && v.isString(); + allInts = allInts && v.isInt32(); + } + } + + /* + * If the array only contains holes, we're done. But if it contains + * undefs, those must be sorted to the front of the array. + */ + n = vec.length(); + if (n == 0 && undefs == 0) { + args.rval().setBoolean(true); + return true; + } + + /* Here len == n + undefs + number_of_holes. */ + if (comp == Match_None) { + /* + * Sort using the default comparator converting all elements to + * strings. + */ + if (allStrings) { + JS_ALWAYS_TRUE(vec.resize(n * 2)); + if (!MergeSort(vec.begin(), n, vec.begin() + n, SortComparatorStrings(cx))) + return false; + } else if (allInts) { + JS_ALWAYS_TRUE(vec.resize(n * 2)); + if (!MergeSort(vec.begin(), n, vec.begin() + n, + SortComparatorLexicographicInt32())) { + return false; + } + } else { + if (!SortLexicographically(cx, &vec, n)) + return false; + } + } else { + if (allInts) { + JS_ALWAYS_TRUE(vec.resize(n * 2)); + if (!MergeSort(vec.begin(), n, vec.begin() + n, SortComparatorInt32s[comp])) + return false; + } else { + if (!SortNumerically(cx, &vec, n, comp)) + return false; + } + } + + // We can omit the type update when neither collecting the elements + // nor calling the default comparator can execute a (getter) function + // that might run user code. + ShouldUpdateTypes updateTypes = !extraIndexed && (allStrings || allInts) + ? ShouldUpdateTypes::DontUpdate + : ShouldUpdateTypes::Update; + if (!SetArrayElements(cx, obj, 0, uint32_t(n), vec.begin(), updateTypes)) + return false; + } + + /* Set undefs that sorted after the rest of elements. */ + if (undefs > 0) { + if (!FillWithUndefined(cx, obj, n, undefs)) + return false; + n += undefs; + } + + /* Re-create any holes that sorted to the end of the array. */ + while (len > n) { + if (!CheckForInterrupt(cx) || !DeletePropertyOrThrow(cx, obj, --len)) + return false; + } + args.rval().setBoolean(true); + return true; +} + +bool +js::NewbornArrayPush(JSContext* cx, HandleObject obj, const Value& v) +{ + HandleArrayObject arr = obj.as<ArrayObject>(); + + MOZ_ASSERT(!v.isMagic()); + MOZ_ASSERT(arr->lengthIsWritable()); + + uint32_t length = arr->length(); + MOZ_ASSERT(length <= arr->getDenseCapacity()); + + if (!arr->ensureElements(cx, length + 1)) + return false; + + arr->setDenseInitializedLength(length + 1); + arr->setLengthInt32(length + 1); + arr->initDenseElementWithType(cx, length, v); + return true; +} + +// ES2017 draft rev 1b0184bc17fc09a8ddcf4aeec9b6d9fcac4eafce +// 22.1.3.18 Array.prototype.push ( ...items ) +bool +js::array_push(JSContext* cx, unsigned argc, Value* vp) +{ + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.push"); + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1. + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + // Step 2. + uint64_t length; + if (!GetLengthProperty(cx, obj, &length)) + return false; + + if (!ObjectMayHaveExtraIndexedProperties(obj) && length <= UINT32_MAX) { + DenseElementResult result = + obj->as<NativeObject>().setOrExtendDenseElements(cx, uint32_t(length), + args.array(), args.length()); + if (result != DenseElementResult::Incomplete) { + if (result == DenseElementResult::Failure) + return false; + + uint32_t newlength = uint32_t(length) + args.length(); + args.rval().setNumber(newlength); + + // setOrExtendDenseElements takes care of updating the length for + // arrays. Handle updates to the length of non-arrays here. + if (!obj->is<ArrayObject>()) { + MOZ_ASSERT(obj->is<NativeObject>()); + return SetLengthProperty(cx, obj, newlength); + } + + return true; + } + } + + // Step 5. + uint64_t newlength = length + args.length(); + if (newlength >= uint64_t(DOUBLE_INTEGRAL_PRECISION_LIMIT)) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_TOO_LONG_ARRAY); + return false; + } + + // Steps 3-6. + if (!SetArrayElements(cx, obj, length, args.length(), args.array())) + return false; + + // Steps 7-8. + args.rval().setNumber(double(newlength)); + return SetLengthProperty(cx, obj, newlength); +} + +// ES2017 draft rev 1b0184bc17fc09a8ddcf4aeec9b6d9fcac4eafce +// 22.1.3.17 Array.prototype.pop ( ) +bool +js::array_pop(JSContext* cx, unsigned argc, Value* vp) +{ + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.pop"); + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1. + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + // Step 2. + uint64_t index; + if (!GetLengthProperty(cx, obj, &index)) + return false; + + // Steps 3-4. + if (index == 0) { + // Step 3.b. + args.rval().setUndefined(); + } else { + // Steps 4.a-b. + index--; + + // Steps 4.c, 4.f. + if (!GetArrayElement(cx, obj, index, args.rval())) + return false; + + // Steps 4.d. + if (!DeletePropertyOrThrow(cx, obj, index)) + return false; + } + + // Steps 3.a, 4.e. + return SetLengthProperty(cx, obj, index); +} + +void +js::ArrayShiftMoveElements(NativeObject* obj) +{ + AutoUnsafeCallWithABI unsafe; + MOZ_ASSERT_IF(obj->is<ArrayObject>(), obj->as<ArrayObject>().lengthIsWritable()); + + size_t initlen = obj->getDenseInitializedLength(); + MOZ_ASSERT(initlen > 0); + + if (!obj->tryShiftDenseElements(1)) + obj->moveDenseElementsNoPreBarrier(0, 1, initlen - 1); +} + +static inline void +SetInitializedLength(JSContext* cx, NativeObject* obj, size_t initlen) +{ + size_t oldInitlen = obj->getDenseInitializedLength(); + obj->setDenseInitializedLength(initlen); + if (initlen < oldInitlen) + obj->shrinkElements(cx, initlen); +} + +static DenseElementResult +MoveDenseElements(JSContext* cx, NativeObject* obj, uint32_t dstStart, uint32_t srcStart, + uint32_t length) +{ + if (obj->denseElementsAreFrozen()) + return DenseElementResult::Incomplete; + + if (!obj->maybeCopyElementsForWrite(cx)) + return DenseElementResult::Failure; + obj->moveDenseElements(dstStart, srcStart, length); + + return DenseElementResult::Success; +} + +static DenseElementResult +ArrayShiftDenseKernel(JSContext* cx, HandleObject obj, MutableHandleValue rval) +{ + if (!IsPackedArray(obj) && ObjectMayHaveExtraIndexedProperties(obj)) + return DenseElementResult::Incomplete; + + if (MaybeInIteration(obj, cx)) + return DenseElementResult::Incomplete; + + size_t initlen = obj->as<NativeObject>().getDenseInitializedLength(); + if (initlen == 0) + return DenseElementResult::Incomplete; + + rval.set(obj->as<NativeObject>().getDenseElement(0)); + if (rval.isMagic(JS_ELEMENTS_HOLE)) + rval.setUndefined(); + + if (obj->as<NativeObject>().tryShiftDenseElements(1)) + return DenseElementResult::Success; + + DenseElementResult result = MoveDenseElements(cx, &obj->as<NativeObject>(), 0, 1, initlen - 1); + if (result != DenseElementResult::Success) + return result; + + SetInitializedLength(cx, obj.as<NativeObject>(), initlen - 1); + return DenseElementResult::Success; +} + +// ES2017 draft rev 1b0184bc17fc09a8ddcf4aeec9b6d9fcac4eafce +// 22.1.3.22 Array.prototype.shift ( ) +bool +js::array_shift(JSContext* cx, unsigned argc, Value* vp) +{ + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.shift"); + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1. + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + // Step 2. + uint64_t len; + if (!GetLengthProperty(cx, obj, &len)) + return false; + + // Step 3. + if (len == 0) { + // Step 3.a. + if (!SetLengthProperty(cx, obj, uint32_t(0))) + return false; + + // Step 3.b. + args.rval().setUndefined(); + return true; + } + + uint64_t newlen = len - 1; + + /* Fast paths. */ + uint64_t startIndex; + DenseElementResult result = ArrayShiftDenseKernel(cx, obj, args.rval()); + if (result != DenseElementResult::Incomplete) { + if (result == DenseElementResult::Failure) + return false; + + if (len <= UINT32_MAX) + return SetLengthProperty(cx, obj, newlen); + + startIndex = UINT32_MAX - 1; + } else { + // Steps 4, 9. + if (!GetElement(cx, obj, 0, args.rval())) + return false; + + startIndex = 0; + } + + // Steps 5-6. + RootedValue value(cx); + for (uint64_t i = startIndex; i < newlen; i++) { + if (!CheckForInterrupt(cx)) + return false; + bool hole; + if (!HasAndGetElement(cx, obj, i + 1, &hole, &value)) + return false; + if (hole) { + if (!DeletePropertyOrThrow(cx, obj, i)) + return false; + } else { + if (!SetArrayElement(cx, obj, i, value)) + return false; + } + } + + // Step 7. + if (!DeletePropertyOrThrow(cx, obj, newlen)) + return false; + + // Step 8. + return SetLengthProperty(cx, obj, newlen); +} + +// ES2017 draft rev 1b0184bc17fc09a8ddcf4aeec9b6d9fcac4eafce +// 22.1.3.29 Array.prototype.unshift ( ...items ) +bool +js::array_unshift(JSContext* cx, unsigned argc, Value* vp) +{ + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.unshift"); + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1. + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + // Step 2. + uint64_t length; + if (!GetLengthProperty(cx, obj, &length)) + return false; + + // Steps 3-4. + if (args.length() > 0) { + bool optimized = false; + do { + if (length > UINT32_MAX) + break; + if (ObjectMayHaveExtraIndexedProperties(obj)) + break; + if (MaybeInIteration(obj, cx)) + break; + NativeObject* nobj = &obj->as<NativeObject>(); + if (nobj->denseElementsAreFrozen()) + break; + if (nobj->is<ArrayObject>() && !nobj->as<ArrayObject>().lengthIsWritable()) + break; + if (!nobj->tryUnshiftDenseElements(args.length())) { + DenseElementResult result = nobj->ensureDenseElements(cx, uint32_t(length), args.length()); + if (result != DenseElementResult::Success) { + if (result == DenseElementResult::Failure) + return false; + MOZ_ASSERT(result == DenseElementResult::Incomplete); + break; + } + if (length > 0) + nobj->moveDenseElements(args.length(), 0, uint32_t(length)); + } + for (uint32_t i = 0; i < args.length(); i++) + nobj->setDenseElementWithType(cx, i, args[i]); + optimized = true; + } while (false); + + if (!optimized) { + if (length > 0) { + uint64_t last = length; + uint64_t upperIndex = last + args.length(); + + // Step 4.a. + if (upperIndex >= uint64_t(DOUBLE_INTEGRAL_PRECISION_LIMIT)) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_TOO_LONG_ARRAY); + return false; + } + + // Steps 4.b-c. + RootedValue value(cx); + do { + --last; --upperIndex; + if (!CheckForInterrupt(cx)) + return false; + bool hole; + if (!HasAndGetElement(cx, obj, last, &hole, &value)) + return false; + if (hole) { + if (!DeletePropertyOrThrow(cx, obj, upperIndex)) + return false; + } else { + if (!SetArrayElement(cx, obj, upperIndex, value)) + return false; + } + } while (last != 0); + } + + // Steps 4.d-f. + /* Copy from args to the bottom of the array. */ + if (!SetArrayElements(cx, obj, 0, args.length(), args.array())) + return false; + } + } + + // Step 5. + uint64_t newlength = length + args.length(); + if (!SetLengthProperty(cx, obj, newlength)) + return false; + + // Step 6. + /* Follow Perl by returning the new array length. */ + args.rval().setNumber(double(newlength)); + return true; +} + +enum class ArrayAccess { + Read, Write +}; + +/* + * Returns true if this is a dense array whose properties ending at |endIndex| + * (exclusive) may be accessed (get, set, delete) directly through its + * contiguous vector of elements without fear of getters, setters, etc. along + * the prototype chain, or of enumerators requiring notification of + * modifications. + */ +template <ArrayAccess Access> +static bool +CanOptimizeForDenseStorage(HandleObject arr, uint64_t endIndex, JSContext* cx) +{ + /* If the desired properties overflow dense storage, we can't optimize. */ + if (endIndex > UINT32_MAX) + return false; + + if (Access == ArrayAccess::Read) { + /* + * Dense storage read access is possible for any packed array as long + * as we only access properties within the initialized length. In all + * other cases we need to ensure there are no other indexed properties + * on this object or on the prototype chain. Callers are required to + * clamp the read length, so it doesn't exceed the initialized length. + */ + if (IsPackedArray(arr) && endIndex <= arr->as<ArrayObject>().getDenseInitializedLength()) + return true; + return !ObjectMayHaveExtraIndexedProperties(arr); + } + + /* There's no optimizing possible if it's not an array. */ + if (!arr->is<ArrayObject>()) + return false; + + /* If the length is non-writable, always pick the slow path */ + if (!arr->as<ArrayObject>().lengthIsWritable()) + return false; + + MOZ_ASSERT(!arr->as<ArrayObject>().denseElementsAreFrozen(), + "writable length implies elements are not frozen"); + + /* Also pick the slow path if the object is being iterated over. */ + if (MaybeInIteration(arr, cx)) + return false; + + /* Or we attempt to write to indices outside the initialized length. */ + if (endIndex > arr->as<ArrayObject>().getDenseInitializedLength()) + return false; + + /* + * Now watch out for getters and setters along the prototype chain or in + * other indexed properties on the object. Packed arrays don't have any + * other indexed properties by definition. + */ + return IsPackedArray(arr) || !ObjectMayHaveExtraIndexedProperties(arr); +} + +static ArrayObject* +CopyDenseArrayElements(JSContext* cx, HandleNativeObject obj, uint32_t begin, uint32_t count) +{ + size_t initlen = obj->getDenseInitializedLength(); + MOZ_ASSERT(initlen <= UINT32_MAX, "initialized length shouldn't exceed UINT32_MAX"); + uint32_t newlength = 0; + if (initlen > begin) + newlength = Min<uint32_t>(initlen - begin, count); + + ArrayObject* narr = NewFullyAllocatedArrayTryReuseGroup(cx, obj, newlength); + if (!narr) + return nullptr; + + MOZ_ASSERT(count >= narr->length()); + narr->setLength(cx, count); + + if (newlength > 0) + narr->initDenseElements(obj, begin, newlength); + + return narr; +} + +static bool +CopyArrayElements(JSContext* cx, HandleObject obj, uint64_t begin, uint64_t count, + HandleArrayObject result) +{ + MOZ_ASSERT(result->length() == count); + + uint64_t startIndex = 0; + RootedValue value(cx); + + // Use dense storage for new indexed properties where possible. + { + uint32_t index = 0; + uint32_t limit = Min<uint32_t>(count, JSID_INT_MAX); + for (; index < limit; index++) { + bool hole; + if (!CheckForInterrupt(cx) || + !HasAndGetElement(cx, obj, begin + index, &hole, &value)) + { + return false; + } + + if (!hole) { + DenseElementResult edResult = result->ensureDenseElements(cx, index, 1); + if (edResult != DenseElementResult::Success) { + if (edResult == DenseElementResult::Failure) + return false; + + MOZ_ASSERT(edResult == DenseElementResult::Incomplete); + if (!DefineDataElement(cx, result, index, value)) + return false; + + break; + } + result->setDenseElementWithType(cx, index, value); + } + } + startIndex = index + 1; + } + + // Copy any remaining elements. + for (uint64_t i = startIndex; i < count; i++) { + bool hole; + if (!CheckForInterrupt(cx) || + !HasAndGetElement(cx, obj, begin + i, &hole, &value)) + { + return false; + } + + if (!hole && !DefineArrayElement(cx, result, i, value)) + return false; + } + return true; +} + +static bool +array_splice_impl(JSContext* cx, unsigned argc, Value* vp, bool returnValueIsUsed) +{ + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.splice"); + CallArgs args = CallArgsFromVp(argc, vp); + + /* Step 1. */ + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + /* Step 2. */ + uint64_t len; + if (!GetLengthProperty(cx, obj, &len)) + return false; + + /* Step 3. */ + double relativeStart; + if (!ToInteger(cx, args.get(0), &relativeStart)) + return false; + + /* Step 4. */ + uint64_t actualStart; + if (relativeStart < 0) + actualStart = Max(len + relativeStart, 0.0); + else + actualStart = Min(relativeStart, double(len)); + + /* Step 5. */ + uint64_t actualDeleteCount; + if (args.length() == 0) { + /* Step 5.b. */ + actualDeleteCount = 0; + } else if (args.length() == 1) { + /* Step 6.b. */ + actualDeleteCount = len - actualStart; + } else { + /* Steps 7.b. */ + double deleteCountDouble; + if (!ToInteger(cx, args[1], &deleteCountDouble)) + return false; + + /* Step 7.c. */ + actualDeleteCount = Min(Max(deleteCountDouble, 0.0), double(len - actualStart)); + + /* Step 8. */ + uint32_t insertCount = args.length() - 2; + if (len + insertCount - actualDeleteCount >= DOUBLE_INTEGRAL_PRECISION_LIMIT) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_TOO_LONG_ARRAY); + return false; + } + } + + MOZ_ASSERT(actualStart + actualDeleteCount <= len); + + RootedObject arr(cx); + if (IsArraySpecies(cx, obj)) { + if (actualDeleteCount > UINT32_MAX) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BAD_ARRAY_LENGTH); + return false; + } + uint32_t count = uint32_t(actualDeleteCount); + + if (CanOptimizeForDenseStorage<ArrayAccess::Read>(obj, actualStart + count, cx)) { + MOZ_ASSERT(actualStart <= UINT32_MAX, + "if actualStart + count <= UINT32_MAX, then actualStart <= UINT32_MAX"); + if (returnValueIsUsed) { + /* Steps 9-12. */ + arr = CopyDenseArrayElements(cx, obj.as<NativeObject>(), uint32_t(actualStart), + count); + if (!arr) + return false; + } + } else { + /* Step 9. */ + arr = NewFullyAllocatedArrayTryReuseGroup(cx, obj, count); + if (!arr) + return false; + + /* Steps 10-11. */ + if (!CopyArrayElements(cx, obj, actualStart, count, arr.as<ArrayObject>())) + return false; + + /* Step 12 (implicit). */ + } + } else { + /* Steps 9. */ + if (!ArraySpeciesCreate(cx, obj, actualDeleteCount, &arr)) + return false; + + /* Steps 10, 11, 11.d. */ + RootedValue fromValue(cx); + for (uint64_t k = 0; k < actualDeleteCount; k++) { + /* Step 11.a (implicit). */ + + if (!CheckForInterrupt(cx)) + return false; + + /* Steps 11.b, 11.c.i. */ + bool hole; + if (!HasAndGetElement(cx, obj, actualStart + k, &hole, &fromValue)) + return false; + + /* Step 11.c. */ + if (!hole) { + /* Step 11.c.ii. */ + if (!DefineArrayElement(cx, arr, k, fromValue)) + return false; + } + } + + /* Step 12. */ + if (!SetLengthProperty(cx, arr, actualDeleteCount)) + return false; + } + + /* Step 14. */ + uint32_t itemCount = (args.length() >= 2) ? (args.length() - 2) : 0; + uint64_t finalLength = len - actualDeleteCount + itemCount; + + if (itemCount < actualDeleteCount) { + /* Step 15: the array is being shrunk. */ + uint64_t sourceIndex = actualStart + actualDeleteCount; + uint64_t targetIndex = actualStart + itemCount; + + if (CanOptimizeForDenseStorage<ArrayAccess::Write>(obj, len, cx)) { + MOZ_ASSERT(sourceIndex <= len && targetIndex <= len && len <= UINT32_MAX, + "sourceIndex and targetIndex are uint32 array indices"); + MOZ_ASSERT(finalLength < len, "finalLength is strictly less than len"); + MOZ_ASSERT(obj->isNative()); + + /* Steps 15.a-b. */ + if (targetIndex != 0 || + !obj->as<NativeObject>().tryShiftDenseElements(sourceIndex)) + { + DenseElementResult result = MoveDenseElements(cx, &obj->as<NativeObject>(), + uint32_t(targetIndex), + uint32_t(sourceIndex), + uint32_t(len - sourceIndex)); + MOZ_ASSERT(result != DenseElementResult::Incomplete); + if (result == DenseElementResult::Failure) + return false; + } + + /* Steps 15.c-d. */ + SetInitializedLength(cx, obj.as<NativeObject>(), finalLength); + } else { + /* + * This is all very slow if the length is very large. We don't yet + * have the ability to iterate in sorted order, so we just do the + * pessimistic thing and let CheckForInterrupt handle the + * fallout. + */ + + /* Steps 15.a-b. */ + RootedValue fromValue(cx); + for (uint64_t from = sourceIndex, to = targetIndex; from < len; from++, to++) { + /* Steps 15.b.i-ii (implicit). */ + + if (!CheckForInterrupt(cx)) + return false; + + /* Steps 15.b.iii, 15.b.iv.1. */ + bool hole; + if (!HasAndGetElement(cx, obj, from, &hole, &fromValue)) + return false; + + /* Steps 15.b.iv. */ + if (hole) { + /* Steps 15.b.v.1. */ + if (!DeletePropertyOrThrow(cx, obj, to)) + return false; + } else { + /* Step 15.b.iv.2. */ + if (!SetArrayElement(cx, obj, to, fromValue)) + return false; + } + } + + /* Steps 15.c-d. */ + if (!DeletePropertiesOrThrow(cx, obj, len, finalLength)) + return false; + } + } else if (itemCount > actualDeleteCount) { + MOZ_ASSERT(actualDeleteCount <= UINT32_MAX); + uint32_t deleteCount = uint32_t(actualDeleteCount); + + /* Step 16. */ + + /* + * Optimize only if the array is already dense and we can extend it to + * its new length. It would be wrong to extend the elements here for a + * number of reasons. + * + * First, this could cause us to fall into the fast-path below. This + * would cause elements to be moved into places past the non-writable + * length. And when the dense initialized length is updated, that'll + * cause the |in| operator to think that those elements actually exist, + * even though, properly, setting them must fail. + * + * Second, extending the elements here will trigger assertions inside + * ensureDenseElements that the elements aren't being extended past the + * length of a non-writable array. This is because extending elements + * will extend capacity -- which might extend them past a non-writable + * length, violating the |capacity <= length| invariant for such + * arrays. And that would make the various JITted fast-path method + * implementations of [].push, [].unshift, and so on wrong. + * + * If the array length is non-writable, this method *will* throw. For + * simplicity, have the slow-path code do it. (Also note that the slow + * path may validly *not* throw -- if all the elements being moved are + * holes.) + */ + if (obj->is<ArrayObject>() && + !ObjectMayHaveExtraIndexedProperties(obj) && + len <= UINT32_MAX) + { + HandleArrayObject arr = obj.as<ArrayObject>(); + if (arr->lengthIsWritable()) { + DenseElementResult result = + arr->ensureDenseElements(cx, uint32_t(len), itemCount - deleteCount); + if (result == DenseElementResult::Failure) + return false; + } + } + + if (CanOptimizeForDenseStorage<ArrayAccess::Write>(obj, finalLength, cx)) { + MOZ_ASSERT((actualStart + actualDeleteCount) <= len && len <= UINT32_MAX, + "start and deleteCount are uint32 array indices"); + MOZ_ASSERT(actualStart + itemCount <= UINT32_MAX, + "can't overflow because |len - actualDeleteCount + itemCount <= UINT32_MAX| " + "and |actualStart <= len - actualDeleteCount| are both true"); + uint32_t start = uint32_t(actualStart); + uint32_t length = uint32_t(len); + + DenseElementResult result = MoveDenseElements(cx, &obj->as<NativeObject>(), + start + itemCount, + start + deleteCount, + length - (start + deleteCount)); + MOZ_ASSERT(result != DenseElementResult::Incomplete); + if (result == DenseElementResult::Failure) + return false; + + /* Steps 16.a-b. */ + SetInitializedLength(cx, obj.as<NativeObject>(), finalLength); + } else { + RootedValue fromValue(cx); + for (uint64_t k = len - actualDeleteCount; k > actualStart; k--) { + if (!CheckForInterrupt(cx)) + return false; + + /* Step 16.b.i. */ + uint64_t from = k + actualDeleteCount - 1; + + /* Step 16.b.ii. */ + uint64_t to = k + itemCount - 1; + + /* Steps 16.b.iii, 16.b.iv.1. */ + bool hole; + if (!HasAndGetElement(cx, obj, from, &hole, &fromValue)) + return false; + + /* Steps 16.b.iv. */ + if (hole) { + /* Step 16.b.v.1. */ + if (!DeletePropertyOrThrow(cx, obj, to)) + return false; + } else { + /* Step 16.b.iv.2. */ + if (!SetArrayElement(cx, obj, to, fromValue)) + return false; + } + } + } + } + + /* Step 13 (reordered). */ + Value* items = args.array() + 2; + + /* Steps 17-18. */ + if (!SetArrayElements(cx, obj, actualStart, itemCount, items)) + return false; + + /* Step 19. */ + if (!SetLengthProperty(cx, obj, finalLength)) + return false; + + /* Step 20. */ + if (returnValueIsUsed) + args.rval().setObject(*arr); + + return true; +} + +/* ES 2016 draft Mar 25, 2016 22.1.3.26. */ +bool +js::array_splice(JSContext* cx, unsigned argc, Value* vp) +{ + return array_splice_impl(cx, argc, vp, true); +} + +static bool +array_splice_noRetVal(JSContext* cx, unsigned argc, Value* vp) +{ + return array_splice_impl(cx, argc, vp, false); +} + +struct SortComparatorIndexes +{ + bool operator()(uint32_t a, uint32_t b, bool* lessOrEqualp) { + *lessOrEqualp = (a <= b); + return true; + } +}; + +// Returns all indexed properties in the range [begin, end) found on |obj| or +// its proto chain. This function does not handle proxies, objects with +// resolve/lookupProperty hooks or indexed getters, as those can introduce +// new properties. In those cases, *success is set to |false|. +static bool +GetIndexedPropertiesInRange(JSContext* cx, HandleObject obj, uint64_t begin, uint64_t end, + Vector<uint32_t>& indexes, bool* success) +{ + *success = false; + + // TODO: Add IdIsIndex with support for large indices. + if (end > UINT32_MAX) + return true; + MOZ_ASSERT(begin <= UINT32_MAX); + + // First, look for proxies or class hooks that can introduce extra + // properties. + JSObject* pobj = obj; + do { + if (!pobj->isNative() || pobj->getClass()->getResolve() || pobj->getOpsLookupProperty()) + return true; + } while ((pobj = pobj->staticPrototype())); + + // Collect indexed property names. + pobj = obj; + do { + // Append dense elements. + NativeObject* nativeObj = &pobj->as<NativeObject>(); + uint32_t initLen = nativeObj->getDenseInitializedLength(); + for (uint32_t i = begin; i < initLen && i < end; i++) { + if (nativeObj->getDenseElement(i).isMagic(JS_ELEMENTS_HOLE)) + continue; + if (!indexes.append(i)) + return false; + } + + // Append typed array elements. + if (nativeObj->is<TypedArrayObject>()) { + uint32_t len = nativeObj->as<TypedArrayObject>().length(); + for (uint32_t i = begin; i < len && i < end; i++) { + if (!indexes.append(i)) + return false; + } + } + + // Append sparse elements. + if (nativeObj->isIndexed()) { + Shape::Range<NoGC> r(nativeObj->lastProperty()); + for (; !r.empty(); r.popFront()) { + Shape& shape = r.front(); + jsid id = shape.propid(); + uint32_t i; + if (!IdIsIndex(id, &i)) + continue; + + if (!(begin <= i && i < end)) + continue; + + // Watch out for getters, they can add new properties. + if (!shape.hasDefaultGetter()) + return true; + + if (!indexes.append(i)) + return false; + } + } + } while ((pobj = pobj->staticPrototype())); + + // Sort the indexes. + Vector<uint32_t> tmp(cx); + size_t n = indexes.length(); + if (!tmp.resize(n)) + return false; + if (!MergeSort(indexes.begin(), n, tmp.begin(), SortComparatorIndexes())) + return false; + + // Remove duplicates. + if (!indexes.empty()) { + uint32_t last = 0; + for (size_t i = 1, len = indexes.length(); i < len; i++) { + uint32_t elem = indexes[i]; + if (indexes[last] != elem) { + last++; + indexes[last] = elem; + } + } + if (!indexes.resize(last + 1)) + return false; + } + + *success = true; + return true; +} + +static bool +SliceSparse(JSContext* cx, HandleObject obj, uint64_t begin, uint64_t end, + HandleArrayObject result) +{ + MOZ_ASSERT(begin <= end); + + Vector<uint32_t> indexes(cx); + bool success; + if (!GetIndexedPropertiesInRange(cx, obj, begin, end, indexes, &success)) + return false; + + if (!success) + return CopyArrayElements(cx, obj, begin, end - begin, result); + + MOZ_ASSERT(end <= UINT32_MAX, + "indices larger than UINT32_MAX should be rejected by GetIndexedPropertiesInRange"); + + RootedValue value(cx); + for (uint32_t index : indexes) { + MOZ_ASSERT(begin <= index && index < end); + + bool hole; + if (!HasAndGetElement(cx, obj, index, &hole, &value)) + return false; + + if (!hole && !DefineDataElement(cx, result, index - uint32_t(begin), value)) + return false; + } + + return true; +} + +static JSObject* +SliceArguments(JSContext* cx, Handle<ArgumentsObject*> argsobj, uint32_t begin, uint32_t count) +{ + MOZ_ASSERT(!argsobj->hasOverriddenLength() && !argsobj->isAnyElementDeleted()); + MOZ_ASSERT(begin + count <= argsobj->initialLength()); + + ArrayObject* result = NewDenseFullyAllocatedArray(cx, count); + if (!result) + return nullptr; + result->setDenseInitializedLength(count); + + MOZ_ASSERT(result->group()->unknownProperties(), + "The default array group has unknown properties, so we can directly initialize the" + "dense elements without needing to update the indexed type set."); + + for (uint32_t index = 0; index < count; index++) { + const Value& v = argsobj->element(begin + index); + result->initDenseElement(index, v); + } + return result; +} + +template <typename T, typename ArrayLength> +static inline ArrayLength +NormalizeSliceTerm(T value, ArrayLength length) +{ + if (value < 0) { + value += length; + if (value < 0) + return 0; + } else if (double(value) > double(length)) { + return length; + } + return ArrayLength(value); +} + +static bool +ArraySliceOrdinary(JSContext* cx, HandleObject obj, uint64_t begin, uint64_t end, + MutableHandleValue rval) +{ + if (begin > end) + begin = end; + + if ((end - begin) > UINT32_MAX) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BAD_ARRAY_LENGTH); + return false; + } + uint32_t count = uint32_t(end - begin); + + if (CanOptimizeForDenseStorage<ArrayAccess::Read>(obj, end, cx)) { + MOZ_ASSERT(begin <= UINT32_MAX, "if end <= UINT32_MAX, then begin <= UINT32_MAX"); + JSObject* narr = CopyDenseArrayElements(cx, obj.as<NativeObject>(), uint32_t(begin), + count); + if (!narr) + return false; + + rval.setObject(*narr); + return true; + } + + if (obj->is<ArgumentsObject>()) { + Handle<ArgumentsObject*> argsobj = obj.as<ArgumentsObject>(); + if (!argsobj->hasOverriddenLength() && !argsobj->isAnyElementDeleted()) { + MOZ_ASSERT(begin <= UINT32_MAX, "begin is limited by |argsobj|'s length"); + JSObject* narr = SliceArguments(cx, argsobj, uint32_t(begin), count); + if (!narr) + return false; + + rval.setObject(*narr); + return true; + } + } + + RootedArrayObject narr(cx, NewPartlyAllocatedArrayTryReuseGroup(cx, obj, count)); + if (!narr) + return false; + + if (end <= UINT32_MAX) { + if (js::GetElementsOp op = obj->getOpsGetElements()) { + ElementAdder adder(cx, narr, count, ElementAdder::CheckHasElemPreserveHoles); + if (!op(cx, obj, uint32_t(begin), uint32_t(end), &adder)) + return false; + + rval.setObject(*narr); + return true; + } + } + + if (obj->isNative() && obj->as<NativeObject>().isIndexed() && count > 1000) { + if (!SliceSparse(cx, obj, begin, end, narr)) + return false; + } else { + if (!CopyArrayElements(cx, obj, begin, count, narr)) + return false; + } + + rval.setObject(*narr); + return true; +} + +/* ES 2016 draft Mar 25, 2016 22.1.3.23. */ +bool +js::array_slice(JSContext* cx, unsigned argc, Value* vp) +{ + AutoGeckoProfilerEntry pseudoFrame(cx, "Array.prototype.slice"); + CallArgs args = CallArgsFromVp(argc, vp); + + /* Step 1. */ + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) + return false; + + /* Step 2. */ + uint64_t length; + if (!GetLengthProperty(cx, obj, &length)) + return false; + + uint64_t k = 0; + uint64_t final = length; + if (args.length() > 0) { + double d; + /* Step 3. */ + if (!ToInteger(cx, args[0], &d)) + return false; + + /* Step 4. */ + k = NormalizeSliceTerm(d, length); + + if (args.hasDefined(1)) { + /* Step 5. */ + if (!ToInteger(cx, args[1], &d)) + return false; + + /* Step 6. */ + final = NormalizeSliceTerm(d, length); + } + } + + if (IsArraySpecies(cx, obj)) { + /* Steps 7-12: Optimized for ordinary array. */ + return ArraySliceOrdinary(cx, obj, k, final, args.rval()); + } + + /* Step 7. */ + uint64_t count = final > k ? final - k : 0; + + /* Step 8. */ + RootedObject arr(cx); + if (!ArraySpeciesCreate(cx, obj, count, &arr)) + return false; + + /* Step 9. */ + uint64_t n = 0; + + /* Step 10. */ + RootedValue kValue(cx); + while (k < final) { + if (!CheckForInterrupt(cx)) + return false; + + /* Steps 10.a-b, and 10.c.i. */ + bool kNotPresent; + if (!HasAndGetElement(cx, obj, k, &kNotPresent, &kValue)) + return false; + + /* Step 10.c. */ + if (!kNotPresent) { + /* Steps 10.c.ii. */ + if (!DefineArrayElement(cx, arr, n, kValue)) + return false; + } + /* Step 10.d. */ + k++; + + /* Step 10.e. */ + n++; + } + + /* Step 11. */ + if (!SetLengthProperty(cx, arr, n)) + return false; + + /* Step 12. */ + args.rval().setObject(*arr); + return true; +} + +static bool +ArraySliceDenseKernel(JSContext* cx, ArrayObject* arr, int32_t beginArg, int32_t endArg, + ArrayObject* result) +{ + uint32_t length = arr->length(); + + uint32_t begin = NormalizeSliceTerm(beginArg, length); + uint32_t end = NormalizeSliceTerm(endArg, length); + + if (begin > end) + begin = end; + + uint32_t count = end - begin; + size_t initlen = arr->getDenseInitializedLength(); + if (initlen > begin) { + uint32_t newlength = Min<uint32_t>(initlen - begin, count); + if (newlength > 0) { + if (!result->ensureElements(cx, newlength)) + return false; + result->initDenseElements(arr, begin, newlength); + } + } + + MOZ_ASSERT(count >= result->length()); + result->setLength(cx, count); + + return true; +} + +JSObject* +js::array_slice_dense(JSContext* cx, HandleObject obj, int32_t begin, int32_t end, + HandleObject result) +{ + if (result && IsArraySpecies(cx, obj)) { + if (!ArraySliceDenseKernel(cx, &obj->as<ArrayObject>(), begin, end, + &result->as<ArrayObject>())) + { + return nullptr; + } + return result; + } + + // Slower path if the JIT wasn't able to allocate an object inline. + JS::AutoValueArray<4> argv(cx); + argv[0].setUndefined(); + argv[1].setObject(*obj); + argv[2].setInt32(begin); + argv[3].setInt32(end); + if (!array_slice(cx, 2, argv.begin())) + return nullptr; + return &argv[0].toObject(); +} + +static bool +array_isArray(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + bool isArray = false; + if (args.get(0).isObject()) { + RootedObject obj(cx, &args[0].toObject()); + if (!IsArray(cx, obj, &isArray)) + return false; + } + args.rval().setBoolean(isArray); + return true; +} + +static bool +ArrayFromCallArgs(JSContext* cx, CallArgs& args, HandleObject proto = nullptr) +{ + ArrayObject* obj = NewCopiedArrayForCallingAllocationSite(cx, args.array(), args.length(), + proto); + if (!obj) + return false; + + args.rval().setObject(*obj); + return true; +} + +static bool +array_of(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + + if (IsArrayConstructor(args.thisv()) || !IsConstructor(args.thisv())) { + // IsArrayConstructor(this) will usually be true in practice. This is + // the most common path. + return ArrayFromCallArgs(cx, args); + } + + // Step 4. + RootedObject obj(cx); + { + FixedConstructArgs<1> cargs(cx); + + cargs[0].setNumber(args.length()); + + if (!Construct(cx, args.thisv(), cargs, args.thisv(), &obj)) + return false; + } + + // Step 8. + for (unsigned k = 0; k < args.length(); k++) { + if (!DefineDataElement(cx, obj, k, args[k])) + return false; + } + + // Steps 9-10. + if (!SetLengthProperty(cx, obj, args.length())) + return false; + + // Step 11. + args.rval().setObject(*obj); + return true; +} + +const JSJitInfo js::array_splice_info = { + { (JSJitGetterOp)array_splice_noRetVal }, + { 0 }, /* unused */ + { 0 }, /* unused */ + JSJitInfo::IgnoresReturnValueNative, + JSJitInfo::AliasEverything, + JSVAL_TYPE_UNDEFINED, +}; + +static const JSFunctionSpec array_methods[] = { + JS_FN(js_toSource_str, array_toSource, 0,0), + JS_SELF_HOSTED_FN(js_toString_str, "ArrayToString", 0,0), + JS_FN(js_toLocaleString_str, array_toLocaleString, 0,0), + + /* Perl-ish methods. */ + JS_INLINABLE_FN("join", array_join, 1,0, ArrayJoin), + JS_FN("reverse", array_reverse, 0,0), + JS_SELF_HOSTED_FN("sort", "ArraySort", 1,0), + JS_INLINABLE_FN("push", array_push, 1,0, ArrayPush), + JS_INLINABLE_FN("pop", array_pop, 0,0, ArrayPop), + JS_INLINABLE_FN("shift", array_shift, 0,0, ArrayShift), + JS_FN("unshift", array_unshift, 1,0), + JS_FNINFO("splice", array_splice, &array_splice_info, 2,0), + + /* Pythonic sequence methods. */ + JS_SELF_HOSTED_FN("concat", "ArrayConcat", 1,0), + JS_INLINABLE_FN("slice", array_slice, 2,0, ArraySlice), + + JS_SELF_HOSTED_FN("lastIndexOf", "ArrayLastIndexOf", 1,0), + JS_SELF_HOSTED_FN("indexOf", "ArrayIndexOf", 1,0), + JS_SELF_HOSTED_FN("forEach", "ArrayForEach", 1,0), + JS_SELF_HOSTED_FN("map", "ArrayMap", 1,0), + JS_SELF_HOSTED_FN("filter", "ArrayFilter", 1,0), + JS_SELF_HOSTED_FN("reduce", "ArrayReduce", 1,0), + JS_SELF_HOSTED_FN("reduceRight", "ArrayReduceRight", 1,0), + JS_SELF_HOSTED_FN("some", "ArraySome", 1,0), + JS_SELF_HOSTED_FN("every", "ArrayEvery", 1,0), + + /* ES6 additions */ + JS_SELF_HOSTED_FN("find", "ArrayFind", 1,0), + JS_SELF_HOSTED_FN("findIndex", "ArrayFindIndex", 1,0), + JS_SELF_HOSTED_FN("copyWithin", "ArrayCopyWithin", 3,0), + + JS_SELF_HOSTED_FN("fill", "ArrayFill", 3,0), + + JS_SELF_HOSTED_SYM_FN(iterator, "ArrayValues", 0,0), + JS_SELF_HOSTED_FN("entries", "ArrayEntries", 0,0), + JS_SELF_HOSTED_FN("keys", "ArrayKeys", 0,0), + JS_SELF_HOSTED_FN("values", "ArrayValues", 0,0), + + /* ES7 additions */ + JS_SELF_HOSTED_FN("includes", "ArrayIncludes", 2,0), + +#ifdef NIGHTLY_BUILD + JS_SELF_HOSTED_FN("flatMap", "ArrayFlatMap", 1,0), + JS_SELF_HOSTED_FN("flatten", "ArrayFlatten", 0,0), +#endif + + JS_FS_END +}; + +static const JSFunctionSpec array_static_methods[] = { + JS_INLINABLE_FN("isArray", array_isArray, 1,0, ArrayIsArray), + JS_SELF_HOSTED_FN("concat", "ArrayStaticConcat", 2,0), + JS_SELF_HOSTED_FN("lastIndexOf", "ArrayStaticLastIndexOf", 2,0), + JS_SELF_HOSTED_FN("indexOf", "ArrayStaticIndexOf", 2,0), + JS_SELF_HOSTED_FN("forEach", "ArrayStaticForEach", 2,0), + JS_SELF_HOSTED_FN("map", "ArrayStaticMap", 2,0), + JS_SELF_HOSTED_FN("filter", "ArrayStaticFilter", 2,0), + JS_SELF_HOSTED_FN("every", "ArrayStaticEvery", 2,0), + JS_SELF_HOSTED_FN("some", "ArrayStaticSome", 2,0), + JS_SELF_HOSTED_FN("reduce", "ArrayStaticReduce", 2,0), + JS_SELF_HOSTED_FN("reduceRight", "ArrayStaticReduceRight", 2,0), + JS_SELF_HOSTED_FN("join", "ArrayStaticJoin", 2,0), + JS_SELF_HOSTED_FN("reverse", "ArrayStaticReverse", 1,0), + JS_SELF_HOSTED_FN("sort", "ArrayStaticSort", 2,0), + JS_SELF_HOSTED_FN("push", "ArrayStaticPush", 2,0), + JS_SELF_HOSTED_FN("pop", "ArrayStaticPop", 1,0), + JS_SELF_HOSTED_FN("shift", "ArrayStaticShift", 1,0), + JS_SELF_HOSTED_FN("unshift", "ArrayStaticUnshift", 2,0), + JS_SELF_HOSTED_FN("splice", "ArrayStaticSplice", 3,0), + JS_SELF_HOSTED_FN("slice", "ArrayStaticSlice", 3,0), + JS_SELF_HOSTED_FN("from", "ArrayFrom", 3,0), + JS_FN("of", array_of, 0,0), + + JS_FS_END +}; + +const JSPropertySpec array_static_props[] = { + JS_SELF_HOSTED_SYM_GET(species, "ArraySpecies", 0), + JS_PS_END +}; + +static inline bool +ArrayConstructorImpl(JSContext* cx, CallArgs& args, bool isConstructor) +{ + RootedObject proto(cx); + if (isConstructor) { + if (!GetPrototypeFromBuiltinConstructor(cx, args, &proto)) + return false; + } else { + // We're emulating |new Array(n)| with |std_Array(n)| in self-hosted JS, + // and the proto should be %ArrayPrototype% regardless of the callee. + proto = GlobalObject::getOrCreateArrayPrototype(cx, cx->global()); + if (!proto) + return false; + } + + if (args.length() != 1 || !args[0].isNumber()) + return ArrayFromCallArgs(cx, args, proto); + + uint32_t length; + if (args[0].isInt32()) { + int32_t i = args[0].toInt32(); + if (i < 0) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BAD_ARRAY_LENGTH); + return false; + } + length = uint32_t(i); + } else { + double d = args[0].toDouble(); + length = ToUint32(d); + if (d != double(length)) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BAD_ARRAY_LENGTH); + return false; + } + } + + ArrayObject* obj = NewPartlyAllocatedArrayForCallingAllocationSite(cx, length, proto); + if (!obj) + return false; + + args.rval().setObject(*obj); + return true; +} + +/* ES5 15.4.2 */ +bool +js::ArrayConstructor(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + return ArrayConstructorImpl(cx, args, /* isConstructor = */ true); +} + +bool +js::array_construct(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + MOZ_ASSERT(!args.isConstructing()); + MOZ_ASSERT(args.length() == 1); + MOZ_ASSERT(args[0].isNumber()); + return ArrayConstructorImpl(cx, args, /* isConstructor = */ false); +} + +ArrayObject* +js::ArrayConstructorOneArg(JSContext* cx, HandleObjectGroup group, int32_t lengthInt) +{ + if (lengthInt < 0) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BAD_ARRAY_LENGTH); + return nullptr; + } + + uint32_t length = uint32_t(lengthInt); + return NewPartlyAllocatedArrayTryUseGroup(cx, group, length); +} + +static JSObject* +CreateArrayPrototype(JSContext* cx, JSProtoKey key) +{ + MOZ_ASSERT(key == JSProto_Array); + RootedObject proto(cx, GlobalObject::getOrCreateObjectPrototype(cx, cx->global())); + if (!proto) + return nullptr; + + RootedObjectGroup group(cx, ObjectGroup::defaultNewGroup(cx, &ArrayObject::class_, + TaggedProto(proto))); + if (!group) + return nullptr; + + RootedShape shape(cx, EmptyShape::getInitialShape(cx, &ArrayObject::class_, TaggedProto(proto), + gc::AllocKind::OBJECT0)); + if (!shape) + return nullptr; + + AutoSetNewObjectMetadata metadata(cx); + RootedArrayObject arrayProto(cx, ArrayObject::createArray(cx, gc::AllocKind::OBJECT4, + gc::TenuredHeap, shape, group, 0, + metadata)); + if (!arrayProto || + !JSObject::setSingleton(cx, arrayProto) || + !JSObject::setDelegate(cx, arrayProto) || + !AddLengthProperty(cx, arrayProto)) + { + return nullptr; + } + + /* + * The default 'new' group of Array.prototype is required by type inference + * to have unknown properties, to simplify handling of e.g. heterogenous + * arrays in JSON and script literals and allows setDenseArrayElement to + * be used without updating the indexed type set for such default arrays. + */ + if (!JSObject::setNewGroupUnknown(cx, &ArrayObject::class_, arrayProto)) + return nullptr; + + return arrayProto; +} + +static bool +array_proto_finish(JSContext* cx, JS::HandleObject ctor, JS::HandleObject proto) +{ + // Add Array.prototype[@@unscopables]. ECMA-262 draft (2016 Mar 19) 22.1.3.32. + RootedObject unscopables(cx, NewObjectWithGivenProto<PlainObject>(cx, nullptr, + SingletonObject)); + if (!unscopables) + return false; + + RootedValue value(cx, BooleanValue(true)); + if (!DefineDataProperty(cx, unscopables, cx->names().copyWithin, value) || + !DefineDataProperty(cx, unscopables, cx->names().entries, value) || + !DefineDataProperty(cx, unscopables, cx->names().fill, value) || + !DefineDataProperty(cx, unscopables, cx->names().find, value) || + !DefineDataProperty(cx, unscopables, cx->names().findIndex, value) || + !DefineDataProperty(cx, unscopables, cx->names().includes, value) || + !DefineDataProperty(cx, unscopables, cx->names().keys, value) || + !DefineDataProperty(cx, unscopables, cx->names().values, value)) + { + return false; + } + + RootedId id(cx, SYMBOL_TO_JSID(cx->wellKnownSymbols().get(JS::SymbolCode::unscopables))); + value.setObject(*unscopables); + return DefineDataProperty(cx, proto, id, value, JSPROP_READONLY); +} + +static const ClassOps ArrayObjectClassOps = { + array_addProperty, + nullptr, /* delProperty */ + nullptr, /* enumerate */ + nullptr, /* resolve */ + nullptr, /* mayResolve */ + nullptr, /* finalize */ + nullptr, /* call */ + nullptr, /* hasInstance */ + nullptr, /* construct */ + nullptr, /* trace */ +}; + +static const ClassSpec ArrayObjectClassSpec = { + GenericCreateConstructor<ArrayConstructor, 1, AllocKind::FUNCTION, &jit::JitInfo_Array>, + CreateArrayPrototype, + array_static_methods, + array_static_props, + array_methods, + nullptr, + array_proto_finish +}; + +const Class ArrayObject::class_ = { + "Array", + JSCLASS_HAS_CACHED_PROTO(JSProto_Array) | JSCLASS_DELAY_METADATA_BUILDER, + &ArrayObjectClassOps, + &ArrayObjectClassSpec +}; + +/* + * Array allocation functions. + */ + +static inline bool +EnsureNewArrayElements(JSContext* cx, ArrayObject* obj, uint32_t length) +{ + /* + * If ensureElements creates dynamically allocated slots, then having + * fixedSlots is a waste. + */ + DebugOnly<uint32_t> cap = obj->getDenseCapacity(); + + if (!obj->ensureElements(cx, length)) + return false; + + MOZ_ASSERT_IF(cap, !obj->hasDynamicElements()); + + return true; +} + +template <uint32_t maxLength> +static MOZ_ALWAYS_INLINE ArrayObject* +NewArray(JSContext* cx, uint32_t length, + HandleObject protoArg, NewObjectKind newKind = GenericObject) +{ + gc::AllocKind allocKind = GuessArrayGCKind(length); + MOZ_ASSERT(CanBeFinalizedInBackground(allocKind, &ArrayObject::class_)); + allocKind = GetBackgroundAllocKind(allocKind); + + RootedObject proto(cx, protoArg); + if (!proto) { + proto = GlobalObject::getOrCreateArrayPrototype(cx, cx->global()); + if (!proto) + return nullptr; + } + + Rooted<TaggedProto> taggedProto(cx, TaggedProto(proto)); + bool isCachable = NewObjectWithTaggedProtoIsCachable(cx, taggedProto, newKind, &ArrayObject::class_); + if (isCachable) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + if (cache.lookupProto(&ArrayObject::class_, proto, allocKind, &entry)) { + gc::InitialHeap heap = GetInitialHeap(newKind, &ArrayObject::class_); + AutoSetNewObjectMetadata metadata(cx); + JSObject* obj = cache.newObjectFromHit(cx, entry, heap); + if (obj) { + /* Fixup the elements pointer and length, which may be incorrect. */ + ArrayObject* arr = &obj->as<ArrayObject>(); + arr->setFixedElements(); + arr->setLength(cx, length); + if (maxLength > 0 && + !EnsureNewArrayElements(cx, arr, std::min(maxLength, length))) + { + return nullptr; + } + return arr; + } + } + } + + RootedObjectGroup group(cx, ObjectGroup::defaultNewGroup(cx, &ArrayObject::class_, + TaggedProto(proto))); + if (!group) + return nullptr; + + /* + * Get a shape with zero fixed slots, regardless of the size class. + * See JSObject::createArray. + */ + RootedShape shape(cx, EmptyShape::getInitialShape(cx, &ArrayObject::class_, + TaggedProto(proto), + gc::AllocKind::OBJECT0)); + if (!shape) + return nullptr; + + AutoSetNewObjectMetadata metadata(cx); + RootedArrayObject arr(cx, ArrayObject::createArray(cx, allocKind, + GetInitialHeap(newKind, &ArrayObject::class_), + shape, group, length, metadata)); + if (!arr) + return nullptr; + + if (shape->isEmptyShape()) { + if (!AddLengthProperty(cx, arr)) + return nullptr; + shape = arr->lastProperty(); + EmptyShape::insertInitialShape(cx, shape, proto); + } + + if (newKind == SingletonObject && !JSObject::setSingleton(cx, arr)) + return nullptr; + + if (isCachable) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + cache.lookupProto(&ArrayObject::class_, proto, allocKind, &entry); + cache.fillProto(entry, &ArrayObject::class_, taggedProto, allocKind, arr); + } + + if (maxLength > 0 && !EnsureNewArrayElements(cx, arr, std::min(maxLength, length))) + return nullptr; + + probes::CreateObject(cx, arr); + return arr; +} + +ArrayObject * JS_FASTCALL +js::NewDenseEmptyArray(JSContext* cx, HandleObject proto /* = nullptr */, + NewObjectKind newKind /* = GenericObject */) +{ + return NewArray<0>(cx, 0, proto, newKind); +} + +ArrayObject * JS_FASTCALL +js::NewDenseFullyAllocatedArray(JSContext* cx, uint32_t length, + HandleObject proto /* = nullptr */, + NewObjectKind newKind /* = GenericObject */) +{ + return NewArray<UINT32_MAX>(cx, length, proto, newKind); +} + +ArrayObject * JS_FASTCALL +js::NewDensePartlyAllocatedArray(JSContext* cx, uint32_t length, + HandleObject proto /* = nullptr */, + NewObjectKind newKind /* = GenericObject */) +{ + return NewArray<ArrayObject::EagerAllocationMaxLength>(cx, length, proto, newKind); +} + +ArrayObject * JS_FASTCALL +js::NewDenseUnallocatedArray(JSContext* cx, uint32_t length, + HandleObject proto /* = nullptr */, + NewObjectKind newKind /* = GenericObject */) +{ + return NewArray<0>(cx, length, proto, newKind); +} + +// values must point at already-rooted Value objects +ArrayObject* +js::NewDenseCopiedArray(JSContext* cx, uint32_t length, const Value* values, + HandleObject proto /* = nullptr */, + NewObjectKind newKind /* = GenericObject */) +{ + ArrayObject* arr = NewArray<UINT32_MAX>(cx, length, proto, newKind); + if (!arr) + return nullptr; + + MOZ_ASSERT(arr->getDenseCapacity() >= length); + MOZ_ASSERT(arr->getDenseInitializedLength() == 0); + + if (values) + arr->initDenseElements(values, length); + + return arr; +} + +ArrayObject* +js::NewDenseFullyAllocatedArrayWithTemplate(JSContext* cx, uint32_t length, JSObject* templateObject) +{ + AutoSetNewObjectMetadata metadata(cx); + gc::AllocKind allocKind = GuessArrayGCKind(length); + MOZ_ASSERT(CanBeFinalizedInBackground(allocKind, &ArrayObject::class_)); + allocKind = GetBackgroundAllocKind(allocKind); + + RootedObjectGroup group(cx, templateObject->group()); + RootedShape shape(cx, templateObject->as<ArrayObject>().lastProperty()); + + gc::InitialHeap heap = GetInitialHeap(GenericObject, &ArrayObject::class_); + Rooted<ArrayObject*> arr(cx, ArrayObject::createArray(cx, allocKind, + heap, shape, group, length, metadata)); + if (!arr) + return nullptr; + + if (!EnsureNewArrayElements(cx, arr, length)) + return nullptr; + + probes::CreateObject(cx, arr); + + return arr; +} + +ArrayObject* +js::NewDenseCopyOnWriteArray(JSContext* cx, HandleArrayObject templateObject, gc::InitialHeap heap) +{ + MOZ_ASSERT(!gc::IsInsideNursery(templateObject)); + + ArrayObject* arr = ArrayObject::createCopyOnWriteArray(cx, heap, templateObject); + if (!arr) + return nullptr; + + probes::CreateObject(cx, arr); + return arr; +} + +// Return a new array with the specified length and allocated capacity (up to +// maxLength), using the specified group if possible. If the specified group +// cannot be used, ensure that the created array at least has the given +// [[Prototype]]. +template <uint32_t maxLength> +static inline ArrayObject* +NewArrayTryUseGroup(JSContext* cx, HandleObjectGroup group, size_t length, + NewObjectKind newKind = GenericObject) +{ + MOZ_ASSERT(newKind != SingletonObject); + + if (group->shouldPreTenure()) + newKind = TenuredObject; + + RootedObject proto(cx, group->proto().toObject()); + ArrayObject* res = NewArray<maxLength>(cx, length, proto, newKind); + if (!res) + return nullptr; + + res->setGroup(group); + + // If the length calculation overflowed, make sure that is marked for the + // new group. + if (res->length() > INT32_MAX) + res->setLength(cx, res->length()); + + return res; +} + +ArrayObject* +js::NewFullyAllocatedArrayTryUseGroup(JSContext* cx, HandleObjectGroup group, size_t length, + NewObjectKind newKind) +{ + return NewArrayTryUseGroup<UINT32_MAX>(cx, group, length, newKind); +} + +ArrayObject* +js::NewPartlyAllocatedArrayTryUseGroup(JSContext* cx, HandleObjectGroup group, size_t length) +{ + return NewArrayTryUseGroup<ArrayObject::EagerAllocationMaxLength>(cx, group, length); +} + +// Return a new array with the default prototype and specified allocated +// capacity and length. If possible, try to reuse the group of the input +// object. The resulting array will either reuse the input object's group or +// will have unknown property types. +template <uint32_t maxLength> +static inline ArrayObject* +NewArrayTryReuseGroup(JSContext* cx, HandleObject obj, size_t length, + NewObjectKind newKind = GenericObject) +{ + if (!obj->is<ArrayObject>()) + return NewArray<maxLength>(cx, length, nullptr, newKind); + + if (obj->staticPrototype() != cx->global()->maybeGetArrayPrototype()) + return NewArray<maxLength>(cx, length, nullptr, newKind); + + RootedObjectGroup group(cx, JSObject::getGroup(cx, obj)); + if (!group) + return nullptr; + + return NewArrayTryUseGroup<maxLength>(cx, group, length, newKind); +} + +ArrayObject* +js::NewFullyAllocatedArrayTryReuseGroup(JSContext* cx, HandleObject obj, size_t length, + NewObjectKind newKind) +{ + return NewArrayTryReuseGroup<UINT32_MAX>(cx, obj, length, newKind); +} + +ArrayObject* +js::NewPartlyAllocatedArrayTryReuseGroup(JSContext* cx, HandleObject obj, size_t length) +{ + return NewArrayTryReuseGroup<ArrayObject::EagerAllocationMaxLength>(cx, obj, length); +} + +ArrayObject* +js::NewFullyAllocatedArrayForCallingAllocationSite(JSContext* cx, size_t length, + NewObjectKind newKind) +{ + RootedObjectGroup group(cx, ObjectGroup::callingAllocationSiteGroup(cx, JSProto_Array)); + if (!group) + return nullptr; + return NewArrayTryUseGroup<UINT32_MAX>(cx, group, length, newKind); +} + +ArrayObject* +js::NewPartlyAllocatedArrayForCallingAllocationSite(JSContext* cx, size_t length, HandleObject proto) +{ + RootedObjectGroup group(cx, ObjectGroup::callingAllocationSiteGroup(cx, JSProto_Array, proto)); + if (!group) + return nullptr; + return NewArrayTryUseGroup<ArrayObject::EagerAllocationMaxLength>(cx, group, length); +} + +ArrayObject* +js::NewCopiedArrayTryUseGroup(JSContext* cx, HandleObjectGroup group, + const Value* vp, size_t length, NewObjectKind newKind, + ShouldUpdateTypes updateTypes) +{ + ArrayObject* obj = NewFullyAllocatedArrayTryUseGroup(cx, group, length, newKind); + if (!obj) + return nullptr; + + DenseElementResult result = obj->setOrExtendDenseElements(cx, 0, vp, length, updateTypes); + if (result == DenseElementResult::Failure) + return nullptr; + + MOZ_ASSERT(result == DenseElementResult::Success); + return obj; +} + +ArrayObject* +js::NewCopiedArrayForCallingAllocationSite(JSContext* cx, const Value* vp, size_t length, + HandleObject proto /* = nullptr */) +{ + RootedObjectGroup group(cx, ObjectGroup::callingAllocationSiteGroup(cx, JSProto_Array, proto)); + if (!group) + return nullptr; + return NewCopiedArrayTryUseGroup(cx, group, vp, length); +} + +#ifdef DEBUG +bool +js::ArrayInfo(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + RootedObject obj(cx); + + for (unsigned i = 0; i < args.length(); i++) { + HandleValue arg = args[i]; + + UniqueChars bytes = DecompileValueGenerator(cx, JSDVG_SEARCH_STACK, arg, nullptr); + if (!bytes) + return false; + if (arg.isPrimitive() || + !(obj = arg.toObjectOrNull())->is<ArrayObject>()) { + fprintf(stderr, "%s: not array\n", bytes.get()); + continue; + } + fprintf(stderr, "%s: (len %u", bytes.get(), obj->as<ArrayObject>().length()); + fprintf(stderr, ", capacity %u", obj->as<ArrayObject>().getDenseCapacity()); + fputs(")\n", stderr); + } + + args.rval().setUndefined(); + return true; +} +#endif + +void +js::ArraySpeciesLookup::initialize(JSContext* cx) +{ + MOZ_ASSERT(state_ == State::Uninitialized); + + // Get the canonical Array.prototype. + NativeObject* arrayProto = cx->global()->maybeGetArrayPrototype(); + + // Leave the cache uninitialized if the Array class itself is not yet + // initialized. + if (!arrayProto) + return; + + // Get the canonical Array constructor. + const Value& arrayCtorValue = cx->global()->getConstructor(JSProto_Array); + MOZ_ASSERT(arrayCtorValue.isObject(), + "The Array constructor is initialized iff Array.prototype is initialized"); + JSFunction* arrayCtor = &arrayCtorValue.toObject().as<JSFunction>(); + + // Shortcut returns below means Array[@@species] will never be + // optimizable, set to disabled now, and clear it later when we succeed. + state_ = State::Disabled; + + // Look up Array.prototype[@@iterator] and ensure it's a data property. + Shape* ctorShape = arrayProto->lookup(cx, NameToId(cx->names().constructor)); + if (!ctorShape || !ctorShape->isDataProperty()) + return; + + // Get the referred value, and ensure it holds the canonical Array + // constructor. + JSFunction* ctorFun; + if (!IsFunctionObject(arrayProto->getSlot(ctorShape->slot()), &ctorFun)) + return; + if (ctorFun != arrayCtor) + return; + + // Look up the '@@species' value on Array + Shape* speciesShape = arrayCtor->lookup(cx, SYMBOL_TO_JSID(cx->wellKnownSymbols().species)); + if (!speciesShape || !speciesShape->hasGetterValue()) + return; + + // Get the referred value, ensure it holds the canonical Array[@@species] + // function. + JSFunction* speciesFun; + if (!IsFunctionObject(speciesShape->getterValue(), &speciesFun)) + return; + if (!IsSelfHostedFunctionWithName(speciesFun, cx->names().ArraySpecies)) + return; + + // Store raw pointers below. This is okay to do here, because all objects + // are in the tenured heap. + MOZ_ASSERT(!IsInsideNursery(arrayProto)); + MOZ_ASSERT(!IsInsideNursery(arrayCtor)); + MOZ_ASSERT(!IsInsideNursery(arrayCtor->lastProperty())); + MOZ_ASSERT(!IsInsideNursery(speciesShape)); + MOZ_ASSERT(!IsInsideNursery(speciesFun)); + MOZ_ASSERT(!IsInsideNursery(arrayProto->lastProperty())); + + state_ = State::Initialized; + arrayProto_ = arrayProto; + arrayConstructor_ = arrayCtor; + arrayConstructorShape_ = arrayCtor->lastProperty(); +#ifdef DEBUG + arraySpeciesShape_ = speciesShape; + canonicalSpeciesFunc_ = speciesFun; +#endif + arrayProtoShape_ = arrayProto->lastProperty(); + arrayProtoConstructorSlot_ = ctorShape->slot(); +} + +void +js::ArraySpeciesLookup::reset() +{ + state_ = State::Uninitialized; + arrayProto_ = nullptr; + arrayConstructor_ = nullptr; + arrayConstructorShape_ = nullptr; +#ifdef DEBUG + arraySpeciesShape_ = nullptr; + canonicalSpeciesFunc_ = nullptr; +#endif + arrayProtoShape_ = nullptr; + arrayProtoConstructorSlot_ = -1; +} + +bool +js::ArraySpeciesLookup::isArrayStateStillSane() +{ + MOZ_ASSERT(state_ == State::Initialized); + + // Ensure that Array.prototype still has the expected shape. + if (arrayProto_->lastProperty() != arrayProtoShape_) + return false; + + // Ensure that Array.prototype.constructor contains the canonical Array + // constructor function. + if (arrayProto_->getSlot(arrayProtoConstructorSlot_) != ObjectValue(*arrayConstructor_)) + return false; + + // Ensure that Array still has the expected shape. + if (arrayConstructor_->lastProperty() != arrayConstructorShape_) + return false; + + // Ensure the species getter contains the canonical @@species function. + // Note: This is currently guaranteed to be always true, because modifying + // the getter property implies a new shape is generated. If this ever + // changes, convert this assertion into an if-statement. + MOZ_ASSERT(arraySpeciesShape_->getterObject() == canonicalSpeciesFunc_); + + return true; +} + +bool +js::ArraySpeciesLookup::tryOptimizeArray(JSContext* cx, ArrayObject* array) +{ + if (state_ == State::Uninitialized) { + // If the cache is not initialized, initialize it. + initialize(cx); + } else if (state_ == State::Initialized && !isArrayStateStillSane()) { + // Otherwise, if the array state is no longer sane, reinitialize. + reset(); + initialize(cx); + } + + // If the cache is disabled or still uninitialized, don't bother trying to + // optimize. + if (state_ != State::Initialized) + return false; + + // By the time we get here, we should have a sane array state. + MOZ_ASSERT(isArrayStateStillSane()); + + // Ensure |array|'s prototype is the actual Array.prototype. + if (array->staticPrototype() != arrayProto_) + return false; + + // Ensure |array| doesn't define any own properties besides its + // non-deletable "length" property. This serves as a quick check to make + // sure |array| doesn't define an own "constructor" property which may + // shadow Array.prototype.constructor. + Shape* shape = array->shape(); + if (shape->previous() && !shape->previous()->isEmptyShape()) + return false; + + MOZ_ASSERT(JSID_IS_ATOM(shape->propidRaw(), cx->names().length)); + return true; +} |