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Diffstat (limited to '')
| -rw-r--r-- | js/src/vm/JSAtom.cpp | 1109 |
1 files changed, 1109 insertions, 0 deletions
diff --git a/js/src/vm/JSAtom.cpp b/js/src/vm/JSAtom.cpp new file mode 100644 index 0000000000..3f384b54d5 --- /dev/null +++ b/js/src/vm/JSAtom.cpp @@ -0,0 +1,1109 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * 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/. */ + +/* + * JS atom table. + */ + +#include "vm/JSAtom-inl.h" + +#include "mozilla/HashFunctions.h" // mozilla::HashStringKnownLength +#include "mozilla/RangedPtr.h" + +#include <iterator> +#include <string.h> + +#include "jstypes.h" + +#include "frontend/CompilationStencil.h" +#include "gc/GC.h" +#include "gc/Marking.h" +#include "gc/MaybeRooted.h" +#include "js/CharacterEncoding.h" +#include "js/friend/ErrorMessages.h" // js::GetErrorMessage, JSMSG_* +#include "js/Symbol.h" +#include "util/Text.h" +#include "vm/JSContext.h" +#include "vm/JSObject.h" +#include "vm/StaticStrings.h" +#include "vm/StringType.h" +#include "vm/SymbolType.h" +#include "vm/WellKnownAtom.h" // js_*_str + +#ifdef ENABLE_RECORD_TUPLE +# include "vm/RecordType.h" +# include "vm/TupleType.h" +#endif + +#include "gc/AtomMarking-inl.h" +#include "vm/JSContext-inl.h" +#include "vm/Realm-inl.h" +#include "vm/StringType-inl.h" + +using namespace js; + +using mozilla::Maybe; +using mozilla::Nothing; +using mozilla::RangedPtr; + +template <typename CharT> +extern void InflateUTF8CharsToBuffer(const JS::UTF8Chars src, CharT* dst, + size_t dstLen, + JS::SmallestEncoding encoding); + +template <typename CharT> +extern bool UTF8EqualsChars(const JS::UTF8Chars utf8, const CharT* chars); + +extern bool GetUTF8AtomizationData(JSContext* cx, const JS::UTF8Chars utf8, + size_t* outlen, + JS::SmallestEncoding* encoding, + HashNumber* hashNum); + +struct js::AtomHasher::Lookup { + union { + const JS::Latin1Char* latin1Chars; + const char16_t* twoByteChars; + const char* utf8Bytes; + }; + enum { TwoByteChar, Latin1, UTF8 } type; + size_t length; + size_t byteLength; + const JSAtom* atom; /* Optional. */ + JS::AutoCheckCannotGC nogc; + + HashNumber hash; + + MOZ_ALWAYS_INLINE Lookup(const char* utf8Bytes, size_t byteLen, size_t length, + HashNumber hash) + : utf8Bytes(utf8Bytes), + type(UTF8), + length(length), + byteLength(byteLen), + atom(nullptr), + hash(hash) {} + + MOZ_ALWAYS_INLINE Lookup(const char16_t* chars, size_t length) + : twoByteChars(chars), + type(TwoByteChar), + length(length), + atom(nullptr), + hash(mozilla::HashString(chars, length)) {} + + MOZ_ALWAYS_INLINE Lookup(const JS::Latin1Char* chars, size_t length) + : latin1Chars(chars), + type(Latin1), + length(length), + atom(nullptr), + hash(mozilla::HashString(chars, length)) {} + + MOZ_ALWAYS_INLINE Lookup(HashNumber hash, const char16_t* chars, + size_t length) + : twoByteChars(chars), + type(TwoByteChar), + length(length), + atom(nullptr), + hash(hash) { + MOZ_ASSERT(hash == mozilla::HashString(chars, length)); + } + + MOZ_ALWAYS_INLINE Lookup(HashNumber hash, const JS::Latin1Char* chars, + size_t length) + : latin1Chars(chars), + type(Latin1), + length(length), + atom(nullptr), + hash(hash) { + MOZ_ASSERT(hash == mozilla::HashString(chars, length)); + } + + inline explicit Lookup(const JSAtom* atom) + : type(atom->hasLatin1Chars() ? Latin1 : TwoByteChar), + length(atom->length()), + atom(atom), + hash(atom->hash()) { + if (type == Latin1) { + latin1Chars = atom->latin1Chars(nogc); + MOZ_ASSERT(mozilla::HashString(latin1Chars, length) == hash); + } else { + MOZ_ASSERT(type == TwoByteChar); + twoByteChars = atom->twoByteChars(nogc); + MOZ_ASSERT(mozilla::HashString(twoByteChars, length) == hash); + } + } +}; + +inline HashNumber js::AtomHasher::hash(const Lookup& l) { return l.hash; } + +MOZ_ALWAYS_INLINE bool js::AtomHasher::match(const WeakHeapPtr<JSAtom*>& entry, + const Lookup& lookup) { + JSAtom* key = entry.unbarrieredGet(); + if (lookup.atom) { + return lookup.atom == key; + } + if (key->length() != lookup.length || key->hash() != lookup.hash) { + return false; + } + + if (key->hasLatin1Chars()) { + const Latin1Char* keyChars = key->latin1Chars(lookup.nogc); + switch (lookup.type) { + case Lookup::Latin1: + return EqualChars(keyChars, lookup.latin1Chars, lookup.length); + case Lookup::TwoByteChar: + return EqualChars(keyChars, lookup.twoByteChars, lookup.length); + case Lookup::UTF8: { + JS::UTF8Chars utf8(lookup.utf8Bytes, lookup.byteLength); + return UTF8EqualsChars(utf8, keyChars); + } + } + } + + const char16_t* keyChars = key->twoByteChars(lookup.nogc); + switch (lookup.type) { + case Lookup::Latin1: + return EqualChars(lookup.latin1Chars, keyChars, lookup.length); + case Lookup::TwoByteChar: + return EqualChars(keyChars, lookup.twoByteChars, lookup.length); + case Lookup::UTF8: { + JS::UTF8Chars utf8(lookup.utf8Bytes, lookup.byteLength); + return UTF8EqualsChars(utf8, keyChars); + } + } + + MOZ_ASSERT_UNREACHABLE("AtomHasher::match unknown type"); + return false; +} + +UniqueChars js::AtomToPrintableString(JSContext* cx, JSAtom* atom) { + return QuoteString(cx, atom); +} + +// Use a low initial capacity for the permanent atoms table to avoid penalizing +// runtimes that create a small number of atoms. +static const uint32_t JS_PERMANENT_ATOM_SIZE = 64; + +MOZ_ALWAYS_INLINE AtomSet::Ptr js::FrozenAtomSet::readonlyThreadsafeLookup( + const AtomSet::Lookup& l) const { + return mSet->readonlyThreadsafeLookup(l); +} + +static JSAtom* PermanentlyAtomizeCharsValidLength(JSContext* cx, + AtomSet& atomSet, + mozilla::HashNumber hash, + const Latin1Char* chars, + size_t length); + +bool JSRuntime::initializeAtoms(JSContext* cx) { + JS::AutoAssertNoGC nogc; + + MOZ_ASSERT(!atoms_); + MOZ_ASSERT(!permanentAtoms_); + + if (parentRuntime) { + permanentAtoms_ = parentRuntime->permanentAtoms_; + + staticStrings = parentRuntime->staticStrings; + commonNames = parentRuntime->commonNames; + emptyString = parentRuntime->emptyString; + wellKnownSymbols = parentRuntime->wellKnownSymbols; + + atoms_ = js_new<AtomsTable>(); + return bool(atoms_); + } + + // NOTE: There's no GC, but `gc.freezePermanentSharedThings` below contains + // a function call that's marked as "Can GC". + Rooted<UniquePtr<AtomSet>> atomSet(cx, + cx->new_<AtomSet>(JS_PERMANENT_ATOM_SIZE)); + if (!atomSet) { + return false; + } + + staticStrings = js_new<StaticStrings>(); + if (!staticStrings || !staticStrings->init(cx)) { + return false; + } + + // The bare symbol names are already part of the well-known set, but their + // descriptions are not, so enumerate them here and add them to the initial + // permanent atoms set below. + static const WellKnownAtomInfo symbolDescInfo[] = { +#define COMMON_NAME_INFO(NAME) \ + {uint32_t(sizeof("Symbol." #NAME) - 1), \ + mozilla::HashStringKnownLength("Symbol." #NAME, \ + sizeof("Symbol." #NAME) - 1), \ + "Symbol." #NAME}, + JS_FOR_EACH_WELL_KNOWN_SYMBOL(COMMON_NAME_INFO) +#undef COMMON_NAME_INFO + }; + + commonNames = js_new<JSAtomState>(); + if (!commonNames) { + return false; + } + + ImmutableTenuredPtr<PropertyName*>* names = + reinterpret_cast<ImmutableTenuredPtr<PropertyName*>*>(commonNames.ref()); + for (size_t i = 0; i < uint32_t(WellKnownAtomId::Limit); i++) { + const auto& info = wellKnownAtomInfos[i]; + JSAtom* atom = PermanentlyAtomizeCharsValidLength( + cx, *atomSet, info.hash, + reinterpret_cast<const Latin1Char*>(info.content), info.length); + if (!atom) { + return false; + } + names->init(atom->asPropertyName()); + names++; + } + + for (const auto& info : symbolDescInfo) { + JSAtom* atom = PermanentlyAtomizeCharsNonStaticValidLength( + cx, *atomSet, info.hash, + reinterpret_cast<const Latin1Char*>(info.content), info.length); + if (!atom) { + return false; + } + names->init(atom->asPropertyName()); + names++; + } + MOZ_ASSERT(uintptr_t(names) == uintptr_t(commonNames + 1)); + + emptyString = commonNames->empty; + + // The self-hosted atoms are those that exist in a self-hosted JS source file, + // but are not defined in any of the well-known atom collections. + if (!cx->runtime()->selfHostStencil_->instantiateSelfHostedAtoms( + cx, *atomSet, cx->runtime()->selfHostStencilInput_->atomCache)) { + return false; + } + + // Create the well-known symbols. + auto wks = js_new<WellKnownSymbols>(); + if (!wks) { + return false; + } + + { + // Prevent GC until we have fully initialized the well known symbols table. + // Faster than zeroing the array and null checking during every GC. + gc::AutoSuppressGC nogc(cx); + + ImmutableTenuredPtr<PropertyName*>* descriptions = + commonNames->wellKnownSymbolDescriptions(); + ImmutableTenuredPtr<JS::Symbol*>* symbols = + reinterpret_cast<ImmutableTenuredPtr<JS::Symbol*>*>(wks); + for (size_t i = 0; i < JS::WellKnownSymbolLimit; i++) { + JS::Symbol* symbol = + JS::Symbol::newWellKnown(cx, JS::SymbolCode(i), descriptions[i]); + if (!symbol) { + ReportOutOfMemory(cx); + return false; + } + symbols[i].init(symbol); + } + + wellKnownSymbols = wks; + } + + if (!gc.freezeSharedAtomsZone()) { + return false; + } + + // The permanent atoms table has now been populated. + permanentAtoms_ = + js_new<FrozenAtomSet>(atomSet.release()); // Takes ownership. + if (!permanentAtoms_) { + return false; + } + + // Initialize the main atoms table. + atoms_ = js_new<AtomsTable>(); + if (!atoms_) { + return false; + } + + return true; +} + +void JSRuntime::finishAtoms() { + js_delete(atoms_.ref()); + + if (!parentRuntime) { + js_delete(permanentAtoms_.ref()); + js_delete(staticStrings.ref()); + js_delete(commonNames.ref()); + js_delete(wellKnownSymbols.ref()); + } + + atoms_ = nullptr; + permanentAtoms_ = nullptr; + staticStrings = nullptr; + commonNames = nullptr; + wellKnownSymbols = nullptr; + emptyString = nullptr; +} + +AtomsTable::AtomsTable() + : atoms(InitialTableSize), atomsAddedWhileSweeping(nullptr) {} + +AtomsTable::~AtomsTable() { MOZ_ASSERT(!atomsAddedWhileSweeping); } + +void AtomsTable::tracePinnedAtoms(JSTracer* trc) { + for (JSAtom* atom : pinnedAtoms) { + TraceRoot(trc, &atom, "pinned atom"); + } +} + +void js::TraceAtoms(JSTracer* trc) { + JSRuntime* rt = trc->runtime(); + if (rt->permanentAtomsPopulated()) { + rt->atoms().tracePinnedAtoms(trc); + } +} + +void AtomsTable::traceWeak(JSTracer* trc) { + for (AtomSet::Enum e(atoms); !e.empty(); e.popFront()) { + JSAtom* atom = e.front().unbarrieredGet(); + MOZ_DIAGNOSTIC_ASSERT(atom); + if (!TraceManuallyBarrieredWeakEdge(trc, &atom, "AtomsTable::atoms")) { + e.removeFront(); + } else { + MOZ_ASSERT(atom == e.front().unbarrieredGet()); + } + } +} + +bool AtomsTable::startIncrementalSweep(Maybe<SweepIterator>& atomsToSweepOut) { + MOZ_ASSERT(JS::RuntimeHeapIsCollecting()); + MOZ_ASSERT(atomsToSweepOut.isNothing()); + MOZ_ASSERT(!atomsAddedWhileSweeping); + + atomsAddedWhileSweeping = js_new<AtomSet>(); + if (!atomsAddedWhileSweeping) { + return false; + } + + atomsToSweepOut.emplace(atoms); + + return true; +} + +void AtomsTable::mergeAtomsAddedWhileSweeping() { + // Add atoms that were added to the secondary table while we were sweeping + // the main table. + + AutoEnterOOMUnsafeRegion oomUnsafe; + + auto newAtoms = atomsAddedWhileSweeping; + atomsAddedWhileSweeping = nullptr; + + for (auto r = newAtoms->all(); !r.empty(); r.popFront()) { + if (!atoms.putNew(AtomHasher::Lookup(r.front().unbarrieredGet()), + r.front())) { + oomUnsafe.crash("Adding atom from secondary table after sweep"); + } + } + + js_delete(newAtoms); +} + +bool AtomsTable::sweepIncrementally(SweepIterator& atomsToSweep, + SliceBudget& budget) { + // Sweep the table incrementally until we run out of work or budget. + while (!atomsToSweep.empty()) { + budget.step(); + if (budget.isOverBudget()) { + return false; + } + + JSAtom* atom = atomsToSweep.front().unbarrieredGet(); + MOZ_DIAGNOSTIC_ASSERT(atom); + if (IsAboutToBeFinalizedUnbarriered(atom)) { + MOZ_ASSERT(!atom->isPinned()); + atomsToSweep.removeFront(); + } else { + MOZ_ASSERT(atom == atomsToSweep.front().unbarrieredGet()); + } + atomsToSweep.popFront(); + } + + mergeAtomsAddedWhileSweeping(); + return true; +} + +size_t AtomsTable::sizeOfIncludingThis( + mozilla::MallocSizeOf mallocSizeOf) const { + size_t size = sizeof(AtomsTable); + size += atoms.shallowSizeOfExcludingThis(mallocSizeOf); + if (atomsAddedWhileSweeping) { + size += atomsAddedWhileSweeping->shallowSizeOfExcludingThis(mallocSizeOf); + } + size += pinnedAtoms.sizeOfExcludingThis(mallocSizeOf); + return size; +} + +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* +AtomizeAndCopyCharsNonStaticValidLengthFromLookup( + JSContext* cx, const CharT* chars, size_t length, + const AtomHasher::Lookup& lookup, const Maybe<uint32_t>& indexValue) { + // Try the per-Zone cache first. If we find the atom there we can avoid the + // markAtom call, and the multiple HashSet lookups below. + Zone* zone = cx->zone(); + MOZ_ASSERT(zone); + AtomSet::AddPtr zonePtr = zone->atomCache().lookupForAdd(lookup); + if (zonePtr) { + // The cache is purged on GC so if we're in the middle of an + // incremental GC we should have barriered the atom when we put + // it in the cache. + JSAtom* atom = zonePtr->unbarrieredGet(); + MOZ_ASSERT(AtomIsMarked(zone, atom)); + return atom; + } + + MOZ_ASSERT(cx->permanentAtomsPopulated()); + + AtomSet::Ptr pp = cx->permanentAtoms().readonlyThreadsafeLookup(lookup); + if (pp) { + JSAtom* atom = pp->get(); + if (MOZ_UNLIKELY(!zone->atomCache().add(zonePtr, atom))) { + ReportOutOfMemory(cx); + return nullptr; + } + + return atom; + } + + JSAtom* atom = cx->atoms().atomizeAndCopyCharsNonStaticValidLength( + cx, chars, length, indexValue, lookup); + if (!atom) { + return nullptr; + } + + if (MOZ_UNLIKELY(!cx->atomMarking().inlinedMarkAtomFallible(cx, atom))) { + ReportOutOfMemory(cx); + return nullptr; + } + + if (MOZ_UNLIKELY(!zone->atomCache().add(zonePtr, atom))) { + ReportOutOfMemory(cx); + return nullptr; + } + + return atom; +} + +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* AllocateNewAtomNonStaticValidLength( + JSContext* cx, const CharT* chars, size_t length, + const Maybe<uint32_t>& indexValue, const AtomHasher::Lookup& lookup); + +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* AllocateNewPermanentAtomNonStaticValidLength( + JSContext* cx, const CharT* chars, size_t length, + const AtomHasher::Lookup& lookup); + +template <typename CharT> +MOZ_ALWAYS_INLINE JSAtom* AtomsTable::atomizeAndCopyCharsNonStaticValidLength( + JSContext* cx, const CharT* chars, size_t length, + const Maybe<uint32_t>& indexValue, const AtomHasher::Lookup& lookup) { + AtomSet::AddPtr p; + + if (!atomsAddedWhileSweeping) { + p = atoms.lookupForAdd(lookup); + } else { + // We're currently sweeping the main atoms table and all new atoms will + // be added to a secondary table. Check this first. + p = atomsAddedWhileSweeping->lookupForAdd(lookup); + + // If that fails check the main table but check if any atom found there + // is dead. + if (!p) { + if (AtomSet::AddPtr p2 = atoms.lookupForAdd(lookup)) { + JSAtom* atom = p2->unbarrieredGet(); + if (!IsAboutToBeFinalizedUnbarriered(atom)) { + p = p2; + } + } + } + } + + if (p) { + return p->get(); + } + + JSAtom* atom = AllocateNewAtomNonStaticValidLength(cx, chars, length, + indexValue, lookup); + if (!atom) { + return nullptr; + } + + // The operations above can't GC; therefore the atoms table has not been + // modified and p is still valid. + AtomSet* addSet = atomsAddedWhileSweeping ? atomsAddedWhileSweeping : &atoms; + if (MOZ_UNLIKELY(!addSet->add(p, atom))) { + ReportOutOfMemory(cx); /* SystemAllocPolicy does not report OOM. */ + return nullptr; + } + + return atom; +} + +/* |chars| must not point into an inline or short string. */ +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* AtomizeAndCopyChars( + JSContext* cx, const CharT* chars, size_t length, + const Maybe<uint32_t>& indexValue) { + if (JSAtom* s = cx->staticStrings().lookup(chars, length)) { + return s; + } + + if (MOZ_UNLIKELY(!JSString::validateLength(cx, length))) { + return nullptr; + } + + AtomHasher::Lookup lookup(chars, length); + return AtomizeAndCopyCharsNonStaticValidLengthFromLookup(cx, chars, length, + lookup, indexValue); +} + +template <typename CharT> +static MOZ_NEVER_INLINE JSAtom* +PermanentlyAtomizeAndCopyCharsNonStaticValidLength( + JSContext* cx, AtomSet& atomSet, const CharT* chars, size_t length, + const AtomHasher::Lookup& lookup) { + MOZ_ASSERT(!cx->permanentAtomsPopulated()); + MOZ_ASSERT(CurrentThreadCanAccessRuntime(cx->runtime())); + + AtomSet::AddPtr p = atomSet.lookupForAdd(lookup); + if (p) { + return p->get(); + } + + JSAtom* atom = + AllocateNewPermanentAtomNonStaticValidLength(cx, chars, length, lookup); + if (!atom) { + return nullptr; + } + + // We are single threaded at this point, and the operations we've done since + // then can't GC; therefore the atoms table has not been modified and p is + // still valid. + if (!atomSet.add(p, atom)) { + ReportOutOfMemory(cx); /* SystemAllocPolicy does not report OOM. */ + return nullptr; + } + + return atom; +} + +struct AtomizeUTF8CharsWrapper { + JS::UTF8Chars utf8; + JS::SmallestEncoding encoding; + + AtomizeUTF8CharsWrapper(const JS::UTF8Chars& chars, + JS::SmallestEncoding minEncode) + : utf8(chars), encoding(minEncode) {} +}; + +// NewAtomNonStaticValidLength has 3 variants. +// This is used by Latin1Char and char16_t. +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* NewAtomNonStaticValidLength( + JSContext* cx, const CharT* chars, size_t length, js::HashNumber hash) { + return NewAtomCopyNMaybeDeflateValidLength(cx, chars, length, hash); +} + +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* MakeUTF8AtomHelperNonStaticValidLength( + JSContext* cx, const AtomizeUTF8CharsWrapper* chars, size_t length, + js::HashNumber hash) { + if (JSInlineString::lengthFits<CharT>(length)) { + CharT* storage; + JSAtom* str = AllocateInlineAtom(cx, length, &storage, hash); + if (!str) { + return nullptr; + } + + InflateUTF8CharsToBuffer(chars->utf8, storage, length, chars->encoding); + return str; + } + + // MakeAtomUTF8Helper is called from deep in the Atomization path, which + // expects functions to fail gracefully with nullptr on OOM, without throwing. + UniquePtr<CharT[], JS::FreePolicy> newStr( + js_pod_arena_malloc<CharT>(js::StringBufferArena, length)); + if (!newStr) { + return nullptr; + } + + InflateUTF8CharsToBuffer(chars->utf8, newStr.get(), length, chars->encoding); + + return JSAtom::newValidLength(cx, std::move(newStr), length, hash); +} + +// Another variant of NewAtomNonStaticValidLength. +static MOZ_ALWAYS_INLINE JSAtom* NewAtomNonStaticValidLength( + JSContext* cx, const AtomizeUTF8CharsWrapper* chars, size_t length, + js::HashNumber hash) { + if (length == 0) { + return cx->emptyString(); + } + + if (chars->encoding == JS::SmallestEncoding::UTF16) { + return MakeUTF8AtomHelperNonStaticValidLength<char16_t>(cx, chars, length, + hash); + } + return MakeUTF8AtomHelperNonStaticValidLength<JS::Latin1Char>(cx, chars, + length, hash); +} + +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* AllocateNewAtomNonStaticValidLength( + JSContext* cx, const CharT* chars, size_t length, + const Maybe<uint32_t>& indexValue, const AtomHasher::Lookup& lookup) { + AutoAllocInAtomsZone ac(cx); + + JSAtom* atom = NewAtomNonStaticValidLength(cx, chars, length, lookup.hash); + if (!atom) { + // Grudgingly forgo last-ditch GC. The alternative would be to manually GC + // here, and retry from the top. + ReportOutOfMemory(cx); + return nullptr; + } + + MOZ_ASSERT(atom->hash() == lookup.hash); + + if (indexValue) { + atom->setIsIndex(*indexValue); + } else { + // We need to call isIndexSlow directly to avoid the flag check in isIndex, + // because we still have to initialize that flag. + uint32_t index; + if (atom->isIndexSlow(&index)) { + atom->setIsIndex(index); + } + } + + return atom; +} + +template <typename CharT> +static MOZ_ALWAYS_INLINE JSAtom* AllocateNewPermanentAtomNonStaticValidLength( + JSContext* cx, const CharT* chars, size_t length, + const AtomHasher::Lookup& lookup) { + AutoAllocInAtomsZone ac(cx); + +#ifdef DEBUG + if constexpr (std::is_same_v<CharT, char16_t>) { + // Can call DontDeflate variant. + MOZ_ASSERT(!CanStoreCharsAsLatin1(chars, length)); + } +#endif + + JSAtom* atom = + NewAtomCopyNDontDeflateValidLength(cx, chars, length, lookup.hash); + if (!atom) { + // Do not bother with a last-ditch GC here since we are very early in + // startup and there is no potential garbage to collect. + ReportOutOfMemory(cx); + return nullptr; + } + atom->makePermanent(); + + MOZ_ASSERT(atom->hash() == lookup.hash); + + uint32_t index; + if (atom->isIndexSlow(&index)) { + atom->setIsIndex(index); + } + + return atom; +} + +JSAtom* js::AtomizeString(JSContext* cx, JSString* str) { + MOZ_ASSERT(cx->isMainThreadContext()); + + if (str->isAtom()) { + return &str->asAtom(); + } + + JSLinearString* linear = str->ensureLinear(cx); + if (!linear) { + return nullptr; + } + + if (JSAtom* atom = cx->caches().stringToAtomCache.lookup(linear)) { + return atom; + } + + Maybe<uint32_t> indexValue; + if (str->hasIndexValue()) { + indexValue.emplace(str->getIndexValue()); + } + + JS::AutoCheckCannotGC nogc; + JSAtom* atom = linear->hasLatin1Chars() + ? AtomizeAndCopyChars(cx, linear->latin1Chars(nogc), + linear->length(), indexValue) + : AtomizeAndCopyChars(cx, linear->twoByteChars(nogc), + linear->length(), indexValue); + if (!atom) { + return nullptr; + } + + cx->caches().stringToAtomCache.maybePut(linear, atom); + + return atom; +} + +bool js::AtomIsPinned(JSContext* cx, JSAtom* atom) { return atom->isPinned(); } + +bool js::PinAtom(JSContext* cx, JSAtom* atom) { + JS::AutoCheckCannotGC nogc; + return cx->runtime()->atoms().maybePinExistingAtom(cx, atom); +} + +bool AtomsTable::maybePinExistingAtom(JSContext* cx, JSAtom* atom) { + MOZ_ASSERT(atom); + + if (atom->isPinned()) { + return true; + } + + if (!pinnedAtoms.append(atom)) { + return false; + } + + atom->setPinned(); + return true; +} + +JSAtom* js::Atomize(JSContext* cx, const char* bytes, size_t length, + const Maybe<uint32_t>& indexValue) { + const Latin1Char* chars = reinterpret_cast<const Latin1Char*>(bytes); + return AtomizeAndCopyChars(cx, chars, length, indexValue); +} + +template <typename CharT> +JSAtom* js::AtomizeChars(JSContext* cx, const CharT* chars, size_t length) { + return AtomizeAndCopyChars(cx, chars, length, Nothing()); +} + +template JSAtom* js::AtomizeChars(JSContext* cx, const Latin1Char* chars, + size_t length); + +template JSAtom* js::AtomizeChars(JSContext* cx, const char16_t* chars, + size_t length); + +JSAtom* js::AtomizeWithoutActiveZone(JSContext* cx, const char* bytes, + size_t length) { + // This is used to implement JS_AtomizeAndPinString{N} when called without an + // active zone. This simplifies the normal atomization code because it can + // assume a non-null cx->zone(). + + MOZ_ASSERT(!cx->zone()); + MOZ_ASSERT(cx->permanentAtomsPopulated()); + + const Latin1Char* chars = reinterpret_cast<const Latin1Char*>(bytes); + + if (JSAtom* s = cx->staticStrings().lookup(chars, length)) { + return s; + } + + if (MOZ_UNLIKELY(!JSString::validateLength(cx, length))) { + return nullptr; + } + + AtomHasher::Lookup lookup(chars, length); + if (AtomSet::Ptr pp = cx->permanentAtoms().readonlyThreadsafeLookup(lookup)) { + return pp->get(); + } + + return cx->atoms().atomizeAndCopyCharsNonStaticValidLength(cx, chars, length, + Nothing(), lookup); +} + +/* |chars| must not point into an inline or short string. */ +template <typename CharT> +JSAtom* js::AtomizeCharsNonStaticValidLength(JSContext* cx, HashNumber hash, + const CharT* chars, + size_t length) { + MOZ_ASSERT(!cx->staticStrings().lookup(chars, length)); + + AtomHasher::Lookup lookup(hash, chars, length); + return AtomizeAndCopyCharsNonStaticValidLengthFromLookup(cx, chars, length, + lookup, Nothing()); +} + +template JSAtom* js::AtomizeCharsNonStaticValidLength(JSContext* cx, + HashNumber hash, + const Latin1Char* chars, + size_t length); + +template JSAtom* js::AtomizeCharsNonStaticValidLength(JSContext* cx, + HashNumber hash, + const char16_t* chars, + size_t length); + +static JSAtom* PermanentlyAtomizeCharsValidLength(JSContext* cx, + AtomSet& atomSet, + HashNumber hash, + const Latin1Char* chars, + size_t length) { + if (JSAtom* s = cx->staticStrings().lookup(chars, length)) { + return s; + } + + return PermanentlyAtomizeCharsNonStaticValidLength(cx, atomSet, hash, chars, + length); +} + +JSAtom* js::PermanentlyAtomizeCharsNonStaticValidLength(JSContext* cx, + AtomSet& atomSet, + HashNumber hash, + const Latin1Char* chars, + size_t length) { + MOZ_ASSERT(!cx->staticStrings().lookup(chars, length)); + MOZ_ASSERT(length <= JSString::MAX_LENGTH); + + AtomHasher::Lookup lookup(hash, chars, length); + return PermanentlyAtomizeAndCopyCharsNonStaticValidLength(cx, atomSet, chars, + length, lookup); +} + +JSAtom* js::AtomizeUTF8Chars(JSContext* cx, const char* utf8Chars, + size_t utf8ByteLength) { + { + StaticStrings& statics = cx->staticStrings(); + + // Handle all pure-ASCII UTF-8 static strings. + if (JSAtom* s = statics.lookup(utf8Chars, utf8ByteLength)) { + return s; + } + + // The only non-ASCII static strings are the single-code point strings + // U+0080 through U+00FF, encoded as + // + // 0b1100'00xx 0b10xx'xxxx + // + // where the encoded code point is the concatenation of the 'x' bits -- and + // where the highest 'x' bit is necessarily 1 (because U+0080 through U+00FF + // all contain an 0x80 bit). + if (utf8ByteLength == 2) { + auto first = static_cast<uint8_t>(utf8Chars[0]); + if ((first & 0b1111'1110) == 0b1100'0010) { + auto second = static_cast<uint8_t>(utf8Chars[1]); + if (mozilla::IsTrailingUnit(mozilla::Utf8Unit(second))) { + uint8_t unit = + static_cast<uint8_t>(first << 6) | (second & 0b0011'1111); + + MOZ_ASSERT(StaticStrings::hasUnit(unit)); + return statics.getUnit(unit); + } + } + + // Fallthrough code handles the cases where the two units aren't a Latin-1 + // code point or are invalid. + } + } + + size_t length; + HashNumber hash; + JS::SmallestEncoding forCopy; + JS::UTF8Chars utf8(utf8Chars, utf8ByteLength); + if (!GetUTF8AtomizationData(cx, utf8, &length, &forCopy, &hash)) { + return nullptr; + } + + if (MOZ_UNLIKELY(!JSString::validateLength(cx, length))) { + return nullptr; + } + + AtomizeUTF8CharsWrapper chars(utf8, forCopy); + AtomHasher::Lookup lookup(utf8Chars, utf8ByteLength, length, hash); + return AtomizeAndCopyCharsNonStaticValidLengthFromLookup(cx, &chars, length, + lookup, Nothing()); +} + +bool js::IndexToIdSlow(JSContext* cx, uint32_t index, MutableHandleId idp) { + MOZ_ASSERT(index > JS::PropertyKey::IntMax); + + char16_t buf[UINT32_CHAR_BUFFER_LENGTH]; + RangedPtr<char16_t> end(std::end(buf), buf, std::end(buf)); + RangedPtr<char16_t> start = BackfillIndexInCharBuffer(index, end); + + JSAtom* atom = AtomizeChars(cx, start.get(), end - start); + if (!atom) { + return false; + } + + idp.set(JS::PropertyKey::NonIntAtom(atom)); + return true; +} + +template <AllowGC allowGC> +static MOZ_ALWAYS_INLINE JSAtom* PrimitiveToAtom(JSContext* cx, + const Value& v) { + MOZ_ASSERT(v.isPrimitive()); + switch (v.type()) { + case ValueType::String: { + JSAtom* atom = AtomizeString(cx, v.toString()); + if (!allowGC && !atom) { + cx->recoverFromOutOfMemory(); + } + return atom; + } + case ValueType::Int32: { + JSAtom* atom = Int32ToAtom(cx, v.toInt32()); + if (!allowGC && !atom) { + cx->recoverFromOutOfMemory(); + } + return atom; + } + case ValueType::Double: { + JSAtom* atom = NumberToAtom(cx, v.toDouble()); + if (!allowGC && !atom) { + cx->recoverFromOutOfMemory(); + } + return atom; + } + case ValueType::Boolean: + return v.toBoolean() ? cx->names().true_ : cx->names().false_; + case ValueType::Null: + return cx->names().null; + case ValueType::Undefined: + return cx->names().undefined; + case ValueType::Symbol: + MOZ_ASSERT(!cx->isHelperThreadContext()); + if constexpr (allowGC) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_SYMBOL_TO_STRING); + } + return nullptr; + case ValueType::BigInt: { + RootedBigInt i(cx, v.toBigInt()); + return BigIntToAtom<allowGC>(cx, i); + } +#ifdef ENABLE_RECORD_TUPLE + case ValueType::ExtendedPrimitive: +#endif + case ValueType::Object: + case ValueType::Magic: + case ValueType::PrivateGCThing: + break; + } + MOZ_CRASH("Unexpected type"); +} + +template <AllowGC allowGC> +static JSAtom* ToAtomSlow( + JSContext* cx, typename MaybeRooted<Value, allowGC>::HandleType arg) { + MOZ_ASSERT(!arg.isString()); + + Value v = arg; + if (!v.isPrimitive()) { + MOZ_ASSERT(!cx->isHelperThreadContext()); + if (!allowGC) { + return nullptr; + } + RootedValue v2(cx, v); + if (!ToPrimitive(cx, JSTYPE_STRING, &v2)) { + return nullptr; + } + v = v2; + } + + return PrimitiveToAtom<allowGC>(cx, v); +} + +template <AllowGC allowGC> +JSAtom* js::ToAtom(JSContext* cx, + typename MaybeRooted<Value, allowGC>::HandleType v) { + if (!v.isString()) { + return ToAtomSlow<allowGC>(cx, v); + } + + JSString* str = v.toString(); + if (str->isAtom()) { + return &str->asAtom(); + } + + JSAtom* atom = AtomizeString(cx, str); + if (!atom && !allowGC) { + MOZ_ASSERT_IF(!cx->isHelperThreadContext(), cx->isThrowingOutOfMemory()); + cx->recoverFromOutOfMemory(); + } + return atom; +} + +template JSAtom* js::ToAtom<CanGC>(JSContext* cx, HandleValue v); +template JSAtom* js::ToAtom<NoGC>(JSContext* cx, const Value& v); + +template <AllowGC allowGC> +bool js::PrimitiveValueToIdSlow( + JSContext* cx, typename MaybeRooted<Value, allowGC>::HandleType v, + typename MaybeRooted<jsid, allowGC>::MutableHandleType idp) { + MOZ_ASSERT(v.isPrimitive()); + MOZ_ASSERT(!v.isString()); + MOZ_ASSERT(!v.isSymbol()); + MOZ_ASSERT_IF(v.isInt32(), !PropertyKey::fitsInInt(v.toInt32())); + + int32_t i; + if (v.isDouble() && mozilla::NumberEqualsInt32(v.toDouble(), &i) && + PropertyKey::fitsInInt(i)) { + idp.set(PropertyKey::Int(i)); + return true; + } + + JSAtom* atom = PrimitiveToAtom<allowGC>(cx, v); + if (!atom) { + return false; + } + + idp.set(AtomToId(atom)); + return true; +} + +template bool js::PrimitiveValueToIdSlow<CanGC>(JSContext* cx, HandleValue v, + MutableHandleId idp); +template bool js::PrimitiveValueToIdSlow<NoGC>(JSContext* cx, const Value& v, + FakeMutableHandle<jsid> idp); + +#ifdef ENABLE_RECORD_TUPLE +bool js::EnsureAtomized(JSContext* cx, MutableHandleValue v, bool* updated) { + if (v.isString()) { + if (v.toString()->isAtom()) { + *updated = false; + return true; + } + + JSAtom* atom = AtomizeString(cx, v.toString()); + if (!atom) { + return false; + } + v.setString(atom); + *updated = true; + return true; + } + + *updated = false; + + if (v.isExtendedPrimitive()) { + JSObject& obj = v.toExtendedPrimitive(); + if (obj.is<RecordType>()) { + return obj.as<RecordType>().ensureAtomized(cx); + } + MOZ_ASSERT(obj.is<TupleType>()); + return obj.as<TupleType>().ensureAtomized(cx); + } + return true; +} +#endif + +Handle<PropertyName*> js::ClassName(JSProtoKey key, JSContext* cx) { + return ClassName(key, cx->names()); +} |