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      1 // Copyright 2014 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "src/factory.h"
      6 
      7 #include "src/allocation-site-scopes.h"
      8 #include "src/base/bits.h"
      9 #include "src/conversions.h"
     10 #include "src/isolate-inl.h"
     11 #include "src/macro-assembler.h"
     12 
     13 namespace v8 {
     14 namespace internal {
     15 
     16 
     17 template<typename T>
     18 Handle<T> Factory::New(Handle<Map> map, AllocationSpace space) {
     19   CALL_HEAP_FUNCTION(
     20       isolate(),
     21       isolate()->heap()->Allocate(*map, space),
     22       T);
     23 }
     24 
     25 
     26 template<typename T>
     27 Handle<T> Factory::New(Handle<Map> map,
     28                        AllocationSpace space,
     29                        Handle<AllocationSite> allocation_site) {
     30   CALL_HEAP_FUNCTION(
     31       isolate(),
     32       isolate()->heap()->Allocate(*map, space, *allocation_site),
     33       T);
     34 }
     35 
     36 
     37 Handle<HeapObject> Factory::NewFillerObject(int size,
     38                                             bool double_align,
     39                                             AllocationSpace space) {
     40   CALL_HEAP_FUNCTION(
     41       isolate(),
     42       isolate()->heap()->AllocateFillerObject(size, double_align, space),
     43       HeapObject);
     44 }
     45 
     46 
     47 Handle<Box> Factory::NewBox(Handle<Object> value) {
     48   Handle<Box> result = Handle<Box>::cast(NewStruct(BOX_TYPE));
     49   result->set_value(*value);
     50   return result;
     51 }
     52 
     53 
     54 Handle<Oddball> Factory::NewOddball(Handle<Map> map,
     55                                     const char* to_string,
     56                                     Handle<Object> to_number,
     57                                     byte kind) {
     58   Handle<Oddball> oddball = New<Oddball>(map, OLD_POINTER_SPACE);
     59   Oddball::Initialize(isolate(), oddball, to_string, to_number, kind);
     60   return oddball;
     61 }
     62 
     63 
     64 Handle<FixedArray> Factory::NewFixedArray(int size, PretenureFlag pretenure) {
     65   DCHECK(0 <= size);
     66   CALL_HEAP_FUNCTION(
     67       isolate(),
     68       isolate()->heap()->AllocateFixedArray(size, pretenure),
     69       FixedArray);
     70 }
     71 
     72 
     73 Handle<FixedArray> Factory::NewFixedArrayWithHoles(int size,
     74                                                    PretenureFlag pretenure) {
     75   DCHECK(0 <= size);
     76   CALL_HEAP_FUNCTION(
     77       isolate(),
     78       isolate()->heap()->AllocateFixedArrayWithFiller(size,
     79                                                       pretenure,
     80                                                       *the_hole_value()),
     81       FixedArray);
     82 }
     83 
     84 
     85 Handle<FixedArray> Factory::NewUninitializedFixedArray(int size) {
     86   CALL_HEAP_FUNCTION(
     87       isolate(),
     88       isolate()->heap()->AllocateUninitializedFixedArray(size),
     89       FixedArray);
     90 }
     91 
     92 
     93 Handle<FixedArrayBase> Factory::NewFixedDoubleArray(int size,
     94                                                     PretenureFlag pretenure) {
     95   DCHECK(0 <= size);
     96   CALL_HEAP_FUNCTION(
     97       isolate(),
     98       isolate()->heap()->AllocateUninitializedFixedDoubleArray(size, pretenure),
     99       FixedArrayBase);
    100 }
    101 
    102 
    103 Handle<FixedArrayBase> Factory::NewFixedDoubleArrayWithHoles(
    104     int size,
    105     PretenureFlag pretenure) {
    106   DCHECK(0 <= size);
    107   Handle<FixedArrayBase> array = NewFixedDoubleArray(size, pretenure);
    108   if (size > 0) {
    109     Handle<FixedDoubleArray> double_array =
    110         Handle<FixedDoubleArray>::cast(array);
    111     for (int i = 0; i < size; ++i) {
    112       double_array->set_the_hole(i);
    113     }
    114   }
    115   return array;
    116 }
    117 
    118 
    119 Handle<ConstantPoolArray> Factory::NewConstantPoolArray(
    120     const ConstantPoolArray::NumberOfEntries& small) {
    121   DCHECK(small.total_count() > 0);
    122   CALL_HEAP_FUNCTION(
    123       isolate(),
    124       isolate()->heap()->AllocateConstantPoolArray(small),
    125       ConstantPoolArray);
    126 }
    127 
    128 
    129 Handle<ConstantPoolArray> Factory::NewExtendedConstantPoolArray(
    130     const ConstantPoolArray::NumberOfEntries& small,
    131     const ConstantPoolArray::NumberOfEntries& extended) {
    132   DCHECK(small.total_count() > 0);
    133   DCHECK(extended.total_count() > 0);
    134   CALL_HEAP_FUNCTION(
    135       isolate(),
    136       isolate()->heap()->AllocateExtendedConstantPoolArray(small, extended),
    137       ConstantPoolArray);
    138 }
    139 
    140 
    141 Handle<OrderedHashSet> Factory::NewOrderedHashSet() {
    142   return OrderedHashSet::Allocate(isolate(), 4);
    143 }
    144 
    145 
    146 Handle<OrderedHashMap> Factory::NewOrderedHashMap() {
    147   return OrderedHashMap::Allocate(isolate(), 4);
    148 }
    149 
    150 
    151 Handle<AccessorPair> Factory::NewAccessorPair() {
    152   Handle<AccessorPair> accessors =
    153       Handle<AccessorPair>::cast(NewStruct(ACCESSOR_PAIR_TYPE));
    154   accessors->set_getter(*the_hole_value(), SKIP_WRITE_BARRIER);
    155   accessors->set_setter(*the_hole_value(), SKIP_WRITE_BARRIER);
    156   return accessors;
    157 }
    158 
    159 
    160 Handle<TypeFeedbackInfo> Factory::NewTypeFeedbackInfo() {
    161   Handle<TypeFeedbackInfo> info =
    162       Handle<TypeFeedbackInfo>::cast(NewStruct(TYPE_FEEDBACK_INFO_TYPE));
    163   info->initialize_storage();
    164   return info;
    165 }
    166 
    167 
    168 // Internalized strings are created in the old generation (data space).
    169 Handle<String> Factory::InternalizeUtf8String(Vector<const char> string) {
    170   Utf8StringKey key(string, isolate()->heap()->HashSeed());
    171   return InternalizeStringWithKey(&key);
    172 }
    173 
    174 
    175 // Internalized strings are created in the old generation (data space).
    176 Handle<String> Factory::InternalizeString(Handle<String> string) {
    177   if (string->IsInternalizedString()) return string;
    178   return StringTable::LookupString(isolate(), string);
    179 }
    180 
    181 
    182 Handle<String> Factory::InternalizeOneByteString(Vector<const uint8_t> string) {
    183   OneByteStringKey key(string, isolate()->heap()->HashSeed());
    184   return InternalizeStringWithKey(&key);
    185 }
    186 
    187 
    188 Handle<String> Factory::InternalizeOneByteString(
    189     Handle<SeqOneByteString> string, int from, int length) {
    190   SeqOneByteSubStringKey key(string, from, length);
    191   return InternalizeStringWithKey(&key);
    192 }
    193 
    194 
    195 Handle<String> Factory::InternalizeTwoByteString(Vector<const uc16> string) {
    196   TwoByteStringKey key(string, isolate()->heap()->HashSeed());
    197   return InternalizeStringWithKey(&key);
    198 }
    199 
    200 
    201 template<class StringTableKey>
    202 Handle<String> Factory::InternalizeStringWithKey(StringTableKey* key) {
    203   return StringTable::LookupKey(isolate(), key);
    204 }
    205 
    206 
    207 MaybeHandle<String> Factory::NewStringFromOneByte(Vector<const uint8_t> string,
    208                                                   PretenureFlag pretenure) {
    209   int length = string.length();
    210   if (length == 1) return LookupSingleCharacterStringFromCode(string[0]);
    211   Handle<SeqOneByteString> result;
    212   ASSIGN_RETURN_ON_EXCEPTION(
    213       isolate(),
    214       result,
    215       NewRawOneByteString(string.length(), pretenure),
    216       String);
    217 
    218   DisallowHeapAllocation no_gc;
    219   // Copy the characters into the new object.
    220   CopyChars(SeqOneByteString::cast(*result)->GetChars(),
    221             string.start(),
    222             length);
    223   return result;
    224 }
    225 
    226 MaybeHandle<String> Factory::NewStringFromUtf8(Vector<const char> string,
    227                                                PretenureFlag pretenure) {
    228   // Check for ASCII first since this is the common case.
    229   const char* start = string.start();
    230   int length = string.length();
    231   int non_ascii_start = String::NonAsciiStart(start, length);
    232   if (non_ascii_start >= length) {
    233     // If the string is ASCII, we do not need to convert the characters
    234     // since UTF8 is backwards compatible with ASCII.
    235     return NewStringFromOneByte(Vector<const uint8_t>::cast(string), pretenure);
    236   }
    237 
    238   // Non-ASCII and we need to decode.
    239   Access<UnicodeCache::Utf8Decoder>
    240       decoder(isolate()->unicode_cache()->utf8_decoder());
    241   decoder->Reset(string.start() + non_ascii_start,
    242                  length - non_ascii_start);
    243   int utf16_length = decoder->Utf16Length();
    244   DCHECK(utf16_length > 0);
    245   // Allocate string.
    246   Handle<SeqTwoByteString> result;
    247   ASSIGN_RETURN_ON_EXCEPTION(
    248       isolate(), result,
    249       NewRawTwoByteString(non_ascii_start + utf16_length, pretenure),
    250       String);
    251   // Copy ASCII portion.
    252   uint16_t* data = result->GetChars();
    253   const char* ascii_data = string.start();
    254   for (int i = 0; i < non_ascii_start; i++) {
    255     *data++ = *ascii_data++;
    256   }
    257   // Now write the remainder.
    258   decoder->WriteUtf16(data, utf16_length);
    259   return result;
    260 }
    261 
    262 
    263 MaybeHandle<String> Factory::NewStringFromTwoByte(Vector<const uc16> string,
    264                                                   PretenureFlag pretenure) {
    265   int length = string.length();
    266   const uc16* start = string.start();
    267   if (String::IsOneByte(start, length)) {
    268     if (length == 1) return LookupSingleCharacterStringFromCode(string[0]);
    269     Handle<SeqOneByteString> result;
    270     ASSIGN_RETURN_ON_EXCEPTION(
    271         isolate(),
    272         result,
    273         NewRawOneByteString(length, pretenure),
    274         String);
    275     CopyChars(result->GetChars(), start, length);
    276     return result;
    277   } else {
    278     Handle<SeqTwoByteString> result;
    279     ASSIGN_RETURN_ON_EXCEPTION(
    280         isolate(),
    281         result,
    282         NewRawTwoByteString(length, pretenure),
    283         String);
    284     CopyChars(result->GetChars(), start, length);
    285     return result;
    286   }
    287 }
    288 
    289 
    290 Handle<String> Factory::NewInternalizedStringFromUtf8(Vector<const char> str,
    291                                                       int chars,
    292                                                       uint32_t hash_field) {
    293   CALL_HEAP_FUNCTION(
    294       isolate(),
    295       isolate()->heap()->AllocateInternalizedStringFromUtf8(
    296           str, chars, hash_field),
    297       String);
    298 }
    299 
    300 
    301 MUST_USE_RESULT Handle<String> Factory::NewOneByteInternalizedString(
    302       Vector<const uint8_t> str,
    303       uint32_t hash_field) {
    304   CALL_HEAP_FUNCTION(
    305       isolate(),
    306       isolate()->heap()->AllocateOneByteInternalizedString(str, hash_field),
    307       String);
    308 }
    309 
    310 
    311 MUST_USE_RESULT Handle<String> Factory::NewOneByteInternalizedSubString(
    312     Handle<SeqOneByteString> string, int offset, int length,
    313     uint32_t hash_field) {
    314   CALL_HEAP_FUNCTION(
    315       isolate(), isolate()->heap()->AllocateOneByteInternalizedString(
    316                      Vector<const uint8_t>(string->GetChars() + offset, length),
    317                      hash_field),
    318       String);
    319 }
    320 
    321 
    322 MUST_USE_RESULT Handle<String> Factory::NewTwoByteInternalizedString(
    323       Vector<const uc16> str,
    324       uint32_t hash_field) {
    325   CALL_HEAP_FUNCTION(
    326       isolate(),
    327       isolate()->heap()->AllocateTwoByteInternalizedString(str, hash_field),
    328       String);
    329 }
    330 
    331 
    332 Handle<String> Factory::NewInternalizedStringImpl(
    333     Handle<String> string, int chars, uint32_t hash_field) {
    334   CALL_HEAP_FUNCTION(
    335       isolate(),
    336       isolate()->heap()->AllocateInternalizedStringImpl(
    337           *string, chars, hash_field),
    338       String);
    339 }
    340 
    341 
    342 MaybeHandle<Map> Factory::InternalizedStringMapForString(
    343     Handle<String> string) {
    344   // If the string is in new space it cannot be used as internalized.
    345   if (isolate()->heap()->InNewSpace(*string)) return MaybeHandle<Map>();
    346 
    347   // Find the corresponding internalized string map for strings.
    348   switch (string->map()->instance_type()) {
    349     case STRING_TYPE: return internalized_string_map();
    350     case ONE_BYTE_STRING_TYPE:
    351       return one_byte_internalized_string_map();
    352     case EXTERNAL_STRING_TYPE: return external_internalized_string_map();
    353     case EXTERNAL_ONE_BYTE_STRING_TYPE:
    354       return external_one_byte_internalized_string_map();
    355     case EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE:
    356       return external_internalized_string_with_one_byte_data_map();
    357     case SHORT_EXTERNAL_STRING_TYPE:
    358       return short_external_internalized_string_map();
    359     case SHORT_EXTERNAL_ONE_BYTE_STRING_TYPE:
    360       return short_external_one_byte_internalized_string_map();
    361     case SHORT_EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE:
    362       return short_external_internalized_string_with_one_byte_data_map();
    363     default: return MaybeHandle<Map>();  // No match found.
    364   }
    365 }
    366 
    367 
    368 MaybeHandle<SeqOneByteString> Factory::NewRawOneByteString(
    369     int length, PretenureFlag pretenure) {
    370   if (length > String::kMaxLength || length < 0) {
    371     THROW_NEW_ERROR(isolate(), NewInvalidStringLengthError(), SeqOneByteString);
    372   }
    373   CALL_HEAP_FUNCTION(
    374       isolate(),
    375       isolate()->heap()->AllocateRawOneByteString(length, pretenure),
    376       SeqOneByteString);
    377 }
    378 
    379 
    380 MaybeHandle<SeqTwoByteString> Factory::NewRawTwoByteString(
    381     int length, PretenureFlag pretenure) {
    382   if (length > String::kMaxLength || length < 0) {
    383     THROW_NEW_ERROR(isolate(), NewInvalidStringLengthError(), SeqTwoByteString);
    384   }
    385   CALL_HEAP_FUNCTION(
    386       isolate(),
    387       isolate()->heap()->AllocateRawTwoByteString(length, pretenure),
    388       SeqTwoByteString);
    389 }
    390 
    391 
    392 Handle<String> Factory::LookupSingleCharacterStringFromCode(uint32_t code) {
    393   if (code <= String::kMaxOneByteCharCodeU) {
    394     {
    395       DisallowHeapAllocation no_allocation;
    396       Object* value = single_character_string_cache()->get(code);
    397       if (value != *undefined_value()) {
    398         return handle(String::cast(value), isolate());
    399       }
    400     }
    401     uint8_t buffer[1];
    402     buffer[0] = static_cast<uint8_t>(code);
    403     Handle<String> result =
    404         InternalizeOneByteString(Vector<const uint8_t>(buffer, 1));
    405     single_character_string_cache()->set(code, *result);
    406     return result;
    407   }
    408   DCHECK(code <= String::kMaxUtf16CodeUnitU);
    409 
    410   Handle<SeqTwoByteString> result = NewRawTwoByteString(1).ToHandleChecked();
    411   result->SeqTwoByteStringSet(0, static_cast<uint16_t>(code));
    412   return result;
    413 }
    414 
    415 
    416 // Returns true for a character in a range.  Both limits are inclusive.
    417 static inline bool Between(uint32_t character, uint32_t from, uint32_t to) {
    418   // This makes uses of the the unsigned wraparound.
    419   return character - from <= to - from;
    420 }
    421 
    422 
    423 static inline Handle<String> MakeOrFindTwoCharacterString(Isolate* isolate,
    424                                                           uint16_t c1,
    425                                                           uint16_t c2) {
    426   // Numeric strings have a different hash algorithm not known by
    427   // LookupTwoCharsStringIfExists, so we skip this step for such strings.
    428   if (!Between(c1, '0', '9') || !Between(c2, '0', '9')) {
    429     Handle<String> result;
    430     if (StringTable::LookupTwoCharsStringIfExists(isolate, c1, c2).
    431         ToHandle(&result)) {
    432       return result;
    433     }
    434   }
    435 
    436   // Now we know the length is 2, we might as well make use of that fact
    437   // when building the new string.
    438   if (static_cast<unsigned>(c1 | c2) <= String::kMaxOneByteCharCodeU) {
    439     // We can do this.
    440     DCHECK(base::bits::IsPowerOfTwo32(String::kMaxOneByteCharCodeU +
    441                                       1));  // because of this.
    442     Handle<SeqOneByteString> str =
    443         isolate->factory()->NewRawOneByteString(2).ToHandleChecked();
    444     uint8_t* dest = str->GetChars();
    445     dest[0] = static_cast<uint8_t>(c1);
    446     dest[1] = static_cast<uint8_t>(c2);
    447     return str;
    448   } else {
    449     Handle<SeqTwoByteString> str =
    450         isolate->factory()->NewRawTwoByteString(2).ToHandleChecked();
    451     uc16* dest = str->GetChars();
    452     dest[0] = c1;
    453     dest[1] = c2;
    454     return str;
    455   }
    456 }
    457 
    458 
    459 template<typename SinkChar, typename StringType>
    460 Handle<String> ConcatStringContent(Handle<StringType> result,
    461                                    Handle<String> first,
    462                                    Handle<String> second) {
    463   DisallowHeapAllocation pointer_stays_valid;
    464   SinkChar* sink = result->GetChars();
    465   String::WriteToFlat(*first, sink, 0, first->length());
    466   String::WriteToFlat(*second, sink + first->length(), 0, second->length());
    467   return result;
    468 }
    469 
    470 
    471 MaybeHandle<String> Factory::NewConsString(Handle<String> left,
    472                                            Handle<String> right) {
    473   int left_length = left->length();
    474   if (left_length == 0) return right;
    475   int right_length = right->length();
    476   if (right_length == 0) return left;
    477 
    478   int length = left_length + right_length;
    479 
    480   if (length == 2) {
    481     uint16_t c1 = left->Get(0);
    482     uint16_t c2 = right->Get(0);
    483     return MakeOrFindTwoCharacterString(isolate(), c1, c2);
    484   }
    485 
    486   // Make sure that an out of memory exception is thrown if the length
    487   // of the new cons string is too large.
    488   if (length > String::kMaxLength || length < 0) {
    489     THROW_NEW_ERROR(isolate(), NewInvalidStringLengthError(), String);
    490   }
    491 
    492   bool left_is_one_byte = left->IsOneByteRepresentation();
    493   bool right_is_one_byte = right->IsOneByteRepresentation();
    494   bool is_one_byte = left_is_one_byte && right_is_one_byte;
    495   bool is_one_byte_data_in_two_byte_string = false;
    496   if (!is_one_byte) {
    497     // At least one of the strings uses two-byte representation so we
    498     // can't use the fast case code for short one-byte strings below, but
    499     // we can try to save memory if all chars actually fit in one-byte.
    500     is_one_byte_data_in_two_byte_string =
    501         left->HasOnlyOneByteChars() && right->HasOnlyOneByteChars();
    502     if (is_one_byte_data_in_two_byte_string) {
    503       isolate()->counters()->string_add_runtime_ext_to_one_byte()->Increment();
    504     }
    505   }
    506 
    507   // If the resulting string is small make a flat string.
    508   if (length < ConsString::kMinLength) {
    509     // Note that neither of the two inputs can be a slice because:
    510     STATIC_ASSERT(ConsString::kMinLength <= SlicedString::kMinLength);
    511     DCHECK(left->IsFlat());
    512     DCHECK(right->IsFlat());
    513 
    514     STATIC_ASSERT(ConsString::kMinLength <= String::kMaxLength);
    515     if (is_one_byte) {
    516       Handle<SeqOneByteString> result =
    517           NewRawOneByteString(length).ToHandleChecked();
    518       DisallowHeapAllocation no_gc;
    519       uint8_t* dest = result->GetChars();
    520       // Copy left part.
    521       const uint8_t* src =
    522           left->IsExternalString()
    523               ? Handle<ExternalOneByteString>::cast(left)->GetChars()
    524               : Handle<SeqOneByteString>::cast(left)->GetChars();
    525       for (int i = 0; i < left_length; i++) *dest++ = src[i];
    526       // Copy right part.
    527       src = right->IsExternalString()
    528                 ? Handle<ExternalOneByteString>::cast(right)->GetChars()
    529                 : Handle<SeqOneByteString>::cast(right)->GetChars();
    530       for (int i = 0; i < right_length; i++) *dest++ = src[i];
    531       return result;
    532     }
    533 
    534     return (is_one_byte_data_in_two_byte_string)
    535         ? ConcatStringContent<uint8_t>(
    536             NewRawOneByteString(length).ToHandleChecked(), left, right)
    537         : ConcatStringContent<uc16>(
    538             NewRawTwoByteString(length).ToHandleChecked(), left, right);
    539   }
    540 
    541   Handle<Map> map = (is_one_byte || is_one_byte_data_in_two_byte_string)
    542                         ? cons_one_byte_string_map()
    543                         : cons_string_map();
    544   Handle<ConsString> result =  New<ConsString>(map, NEW_SPACE);
    545 
    546   DisallowHeapAllocation no_gc;
    547   WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
    548 
    549   result->set_hash_field(String::kEmptyHashField);
    550   result->set_length(length);
    551   result->set_first(*left, mode);
    552   result->set_second(*right, mode);
    553   return result;
    554 }
    555 
    556 
    557 Handle<String> Factory::NewProperSubString(Handle<String> str,
    558                                            int begin,
    559                                            int end) {
    560 #if VERIFY_HEAP
    561   if (FLAG_verify_heap) str->StringVerify();
    562 #endif
    563   DCHECK(begin > 0 || end < str->length());
    564 
    565   str = String::Flatten(str);
    566 
    567   int length = end - begin;
    568   if (length <= 0) return empty_string();
    569   if (length == 1) {
    570     return LookupSingleCharacterStringFromCode(str->Get(begin));
    571   }
    572   if (length == 2) {
    573     // Optimization for 2-byte strings often used as keys in a decompression
    574     // dictionary.  Check whether we already have the string in the string
    575     // table to prevent creation of many unnecessary strings.
    576     uint16_t c1 = str->Get(begin);
    577     uint16_t c2 = str->Get(begin + 1);
    578     return MakeOrFindTwoCharacterString(isolate(), c1, c2);
    579   }
    580 
    581   if (!FLAG_string_slices || length < SlicedString::kMinLength) {
    582     if (str->IsOneByteRepresentation()) {
    583       Handle<SeqOneByteString> result =
    584           NewRawOneByteString(length).ToHandleChecked();
    585       uint8_t* dest = result->GetChars();
    586       DisallowHeapAllocation no_gc;
    587       String::WriteToFlat(*str, dest, begin, end);
    588       return result;
    589     } else {
    590       Handle<SeqTwoByteString> result =
    591           NewRawTwoByteString(length).ToHandleChecked();
    592       uc16* dest = result->GetChars();
    593       DisallowHeapAllocation no_gc;
    594       String::WriteToFlat(*str, dest, begin, end);
    595       return result;
    596     }
    597   }
    598 
    599   int offset = begin;
    600 
    601   if (str->IsSlicedString()) {
    602     Handle<SlicedString> slice = Handle<SlicedString>::cast(str);
    603     str = Handle<String>(slice->parent(), isolate());
    604     offset += slice->offset();
    605   }
    606 
    607   DCHECK(str->IsSeqString() || str->IsExternalString());
    608   Handle<Map> map = str->IsOneByteRepresentation()
    609                         ? sliced_one_byte_string_map()
    610                         : sliced_string_map();
    611   Handle<SlicedString> slice = New<SlicedString>(map, NEW_SPACE);
    612 
    613   slice->set_hash_field(String::kEmptyHashField);
    614   slice->set_length(length);
    615   slice->set_parent(*str);
    616   slice->set_offset(offset);
    617   return slice;
    618 }
    619 
    620 
    621 MaybeHandle<String> Factory::NewExternalStringFromOneByte(
    622     const ExternalOneByteString::Resource* resource) {
    623   size_t length = resource->length();
    624   if (length > static_cast<size_t>(String::kMaxLength)) {
    625     THROW_NEW_ERROR(isolate(), NewInvalidStringLengthError(), String);
    626   }
    627 
    628   Handle<Map> map = external_one_byte_string_map();
    629   Handle<ExternalOneByteString> external_string =
    630       New<ExternalOneByteString>(map, NEW_SPACE);
    631   external_string->set_length(static_cast<int>(length));
    632   external_string->set_hash_field(String::kEmptyHashField);
    633   external_string->set_resource(resource);
    634 
    635   return external_string;
    636 }
    637 
    638 
    639 MaybeHandle<String> Factory::NewExternalStringFromTwoByte(
    640     const ExternalTwoByteString::Resource* resource) {
    641   size_t length = resource->length();
    642   if (length > static_cast<size_t>(String::kMaxLength)) {
    643     THROW_NEW_ERROR(isolate(), NewInvalidStringLengthError(), String);
    644   }
    645 
    646   // For small strings we check whether the resource contains only
    647   // one byte characters.  If yes, we use a different string map.
    648   static const size_t kOneByteCheckLengthLimit = 32;
    649   bool is_one_byte = length <= kOneByteCheckLengthLimit &&
    650       String::IsOneByte(resource->data(), static_cast<int>(length));
    651   Handle<Map> map = is_one_byte ?
    652       external_string_with_one_byte_data_map() : external_string_map();
    653   Handle<ExternalTwoByteString> external_string =
    654       New<ExternalTwoByteString>(map, NEW_SPACE);
    655   external_string->set_length(static_cast<int>(length));
    656   external_string->set_hash_field(String::kEmptyHashField);
    657   external_string->set_resource(resource);
    658 
    659   return external_string;
    660 }
    661 
    662 
    663 Handle<Symbol> Factory::NewSymbol() {
    664   CALL_HEAP_FUNCTION(
    665       isolate(),
    666       isolate()->heap()->AllocateSymbol(),
    667       Symbol);
    668 }
    669 
    670 
    671 Handle<Symbol> Factory::NewPrivateSymbol() {
    672   Handle<Symbol> symbol = NewSymbol();
    673   symbol->set_is_private(true);
    674   return symbol;
    675 }
    676 
    677 
    678 Handle<Symbol> Factory::NewPrivateOwnSymbol() {
    679   Handle<Symbol> symbol = NewSymbol();
    680   symbol->set_is_private(true);
    681   symbol->set_is_own(true);
    682   return symbol;
    683 }
    684 
    685 
    686 Handle<Context> Factory::NewNativeContext() {
    687   Handle<FixedArray> array = NewFixedArray(Context::NATIVE_CONTEXT_SLOTS);
    688   array->set_map_no_write_barrier(*native_context_map());
    689   Handle<Context> context = Handle<Context>::cast(array);
    690   context->set_js_array_maps(*undefined_value());
    691   DCHECK(context->IsNativeContext());
    692   return context;
    693 }
    694 
    695 
    696 Handle<Context> Factory::NewGlobalContext(Handle<JSFunction> function,
    697                                           Handle<ScopeInfo> scope_info) {
    698   Handle<FixedArray> array =
    699       NewFixedArray(scope_info->ContextLength(), TENURED);
    700   array->set_map_no_write_barrier(*global_context_map());
    701   Handle<Context> context = Handle<Context>::cast(array);
    702   context->set_closure(*function);
    703   context->set_previous(function->context());
    704   context->set_extension(*scope_info);
    705   context->set_global_object(function->context()->global_object());
    706   DCHECK(context->IsGlobalContext());
    707   return context;
    708 }
    709 
    710 
    711 Handle<Context> Factory::NewModuleContext(Handle<ScopeInfo> scope_info) {
    712   Handle<FixedArray> array =
    713       NewFixedArray(scope_info->ContextLength(), TENURED);
    714   array->set_map_no_write_barrier(*module_context_map());
    715   // Instance link will be set later.
    716   Handle<Context> context = Handle<Context>::cast(array);
    717   context->set_extension(Smi::FromInt(0));
    718   return context;
    719 }
    720 
    721 
    722 Handle<Context> Factory::NewFunctionContext(int length,
    723                                             Handle<JSFunction> function) {
    724   DCHECK(length >= Context::MIN_CONTEXT_SLOTS);
    725   Handle<FixedArray> array = NewFixedArray(length);
    726   array->set_map_no_write_barrier(*function_context_map());
    727   Handle<Context> context = Handle<Context>::cast(array);
    728   context->set_closure(*function);
    729   context->set_previous(function->context());
    730   context->set_extension(Smi::FromInt(0));
    731   context->set_global_object(function->context()->global_object());
    732   return context;
    733 }
    734 
    735 
    736 Handle<Context> Factory::NewCatchContext(Handle<JSFunction> function,
    737                                          Handle<Context> previous,
    738                                          Handle<String> name,
    739                                          Handle<Object> thrown_object) {
    740   STATIC_ASSERT(Context::MIN_CONTEXT_SLOTS == Context::THROWN_OBJECT_INDEX);
    741   Handle<FixedArray> array = NewFixedArray(Context::MIN_CONTEXT_SLOTS + 1);
    742   array->set_map_no_write_barrier(*catch_context_map());
    743   Handle<Context> context = Handle<Context>::cast(array);
    744   context->set_closure(*function);
    745   context->set_previous(*previous);
    746   context->set_extension(*name);
    747   context->set_global_object(previous->global_object());
    748   context->set(Context::THROWN_OBJECT_INDEX, *thrown_object);
    749   return context;
    750 }
    751 
    752 
    753 Handle<Context> Factory::NewWithContext(Handle<JSFunction> function,
    754                                         Handle<Context> previous,
    755                                         Handle<JSReceiver> extension) {
    756   Handle<FixedArray> array = NewFixedArray(Context::MIN_CONTEXT_SLOTS);
    757   array->set_map_no_write_barrier(*with_context_map());
    758   Handle<Context> context = Handle<Context>::cast(array);
    759   context->set_closure(*function);
    760   context->set_previous(*previous);
    761   context->set_extension(*extension);
    762   context->set_global_object(previous->global_object());
    763   return context;
    764 }
    765 
    766 
    767 Handle<Context> Factory::NewBlockContext(Handle<JSFunction> function,
    768                                          Handle<Context> previous,
    769                                          Handle<ScopeInfo> scope_info) {
    770   Handle<FixedArray> array =
    771       NewFixedArrayWithHoles(scope_info->ContextLength());
    772   array->set_map_no_write_barrier(*block_context_map());
    773   Handle<Context> context = Handle<Context>::cast(array);
    774   context->set_closure(*function);
    775   context->set_previous(*previous);
    776   context->set_extension(*scope_info);
    777   context->set_global_object(previous->global_object());
    778   return context;
    779 }
    780 
    781 
    782 Handle<Struct> Factory::NewStruct(InstanceType type) {
    783   CALL_HEAP_FUNCTION(
    784       isolate(),
    785       isolate()->heap()->AllocateStruct(type),
    786       Struct);
    787 }
    788 
    789 
    790 Handle<CodeCache> Factory::NewCodeCache() {
    791   Handle<CodeCache> code_cache =
    792       Handle<CodeCache>::cast(NewStruct(CODE_CACHE_TYPE));
    793   code_cache->set_default_cache(*empty_fixed_array(), SKIP_WRITE_BARRIER);
    794   code_cache->set_normal_type_cache(*undefined_value(), SKIP_WRITE_BARRIER);
    795   return code_cache;
    796 }
    797 
    798 
    799 Handle<AliasedArgumentsEntry> Factory::NewAliasedArgumentsEntry(
    800     int aliased_context_slot) {
    801   Handle<AliasedArgumentsEntry> entry = Handle<AliasedArgumentsEntry>::cast(
    802       NewStruct(ALIASED_ARGUMENTS_ENTRY_TYPE));
    803   entry->set_aliased_context_slot(aliased_context_slot);
    804   return entry;
    805 }
    806 
    807 
    808 Handle<DeclaredAccessorDescriptor> Factory::NewDeclaredAccessorDescriptor() {
    809   return Handle<DeclaredAccessorDescriptor>::cast(
    810       NewStruct(DECLARED_ACCESSOR_DESCRIPTOR_TYPE));
    811 }
    812 
    813 
    814 Handle<DeclaredAccessorInfo> Factory::NewDeclaredAccessorInfo() {
    815   Handle<DeclaredAccessorInfo> info =
    816       Handle<DeclaredAccessorInfo>::cast(
    817           NewStruct(DECLARED_ACCESSOR_INFO_TYPE));
    818   info->set_flag(0);  // Must clear the flag, it was initialized as undefined.
    819   return info;
    820 }
    821 
    822 
    823 Handle<ExecutableAccessorInfo> Factory::NewExecutableAccessorInfo() {
    824   Handle<ExecutableAccessorInfo> info =
    825       Handle<ExecutableAccessorInfo>::cast(
    826           NewStruct(EXECUTABLE_ACCESSOR_INFO_TYPE));
    827   info->set_flag(0);  // Must clear the flag, it was initialized as undefined.
    828   return info;
    829 }
    830 
    831 
    832 Handle<Script> Factory::NewScript(Handle<String> source) {
    833   // Generate id for this script.
    834   Heap* heap = isolate()->heap();
    835   int id = heap->last_script_id()->value() + 1;
    836   if (!Smi::IsValid(id) || id < 0) id = 1;
    837   heap->set_last_script_id(Smi::FromInt(id));
    838 
    839   // Create and initialize script object.
    840   Handle<Foreign> wrapper = NewForeign(0, TENURED);
    841   Handle<Script> script = Handle<Script>::cast(NewStruct(SCRIPT_TYPE));
    842   script->set_source(*source);
    843   script->set_name(heap->undefined_value());
    844   script->set_id(Smi::FromInt(id));
    845   script->set_line_offset(Smi::FromInt(0));
    846   script->set_column_offset(Smi::FromInt(0));
    847   script->set_context_data(heap->undefined_value());
    848   script->set_type(Smi::FromInt(Script::TYPE_NORMAL));
    849   script->set_wrapper(*wrapper);
    850   script->set_line_ends(heap->undefined_value());
    851   script->set_eval_from_shared(heap->undefined_value());
    852   script->set_eval_from_instructions_offset(Smi::FromInt(0));
    853   script->set_flags(Smi::FromInt(0));
    854 
    855   return script;
    856 }
    857 
    858 
    859 Handle<Foreign> Factory::NewForeign(Address addr, PretenureFlag pretenure) {
    860   CALL_HEAP_FUNCTION(isolate(),
    861                      isolate()->heap()->AllocateForeign(addr, pretenure),
    862                      Foreign);
    863 }
    864 
    865 
    866 Handle<Foreign> Factory::NewForeign(const AccessorDescriptor* desc) {
    867   return NewForeign((Address) desc, TENURED);
    868 }
    869 
    870 
    871 Handle<ByteArray> Factory::NewByteArray(int length, PretenureFlag pretenure) {
    872   DCHECK(0 <= length);
    873   CALL_HEAP_FUNCTION(
    874       isolate(),
    875       isolate()->heap()->AllocateByteArray(length, pretenure),
    876       ByteArray);
    877 }
    878 
    879 
    880 Handle<ExternalArray> Factory::NewExternalArray(int length,
    881                                                 ExternalArrayType array_type,
    882                                                 void* external_pointer,
    883                                                 PretenureFlag pretenure) {
    884   DCHECK(0 <= length && length <= Smi::kMaxValue);
    885   CALL_HEAP_FUNCTION(
    886       isolate(),
    887       isolate()->heap()->AllocateExternalArray(length,
    888                                                array_type,
    889                                                external_pointer,
    890                                                pretenure),
    891       ExternalArray);
    892 }
    893 
    894 
    895 Handle<FixedTypedArrayBase> Factory::NewFixedTypedArray(
    896     int length,
    897     ExternalArrayType array_type,
    898     PretenureFlag pretenure) {
    899   DCHECK(0 <= length && length <= Smi::kMaxValue);
    900   CALL_HEAP_FUNCTION(
    901       isolate(),
    902       isolate()->heap()->AllocateFixedTypedArray(length,
    903                                                  array_type,
    904                                                  pretenure),
    905       FixedTypedArrayBase);
    906 }
    907 
    908 
    909 Handle<Cell> Factory::NewCell(Handle<Object> value) {
    910   AllowDeferredHandleDereference convert_to_cell;
    911   CALL_HEAP_FUNCTION(
    912       isolate(),
    913       isolate()->heap()->AllocateCell(*value),
    914       Cell);
    915 }
    916 
    917 
    918 Handle<PropertyCell> Factory::NewPropertyCellWithHole() {
    919   CALL_HEAP_FUNCTION(
    920       isolate(),
    921       isolate()->heap()->AllocatePropertyCell(),
    922       PropertyCell);
    923 }
    924 
    925 
    926 Handle<PropertyCell> Factory::NewPropertyCell(Handle<Object> value) {
    927   AllowDeferredHandleDereference convert_to_cell;
    928   Handle<PropertyCell> cell = NewPropertyCellWithHole();
    929   PropertyCell::SetValueInferType(cell, value);
    930   return cell;
    931 }
    932 
    933 
    934 Handle<AllocationSite> Factory::NewAllocationSite() {
    935   Handle<Map> map = allocation_site_map();
    936   Handle<AllocationSite> site = New<AllocationSite>(map, OLD_POINTER_SPACE);
    937   site->Initialize();
    938 
    939   // Link the site
    940   site->set_weak_next(isolate()->heap()->allocation_sites_list());
    941   isolate()->heap()->set_allocation_sites_list(*site);
    942   return site;
    943 }
    944 
    945 
    946 Handle<Map> Factory::NewMap(InstanceType type,
    947                             int instance_size,
    948                             ElementsKind elements_kind) {
    949   CALL_HEAP_FUNCTION(
    950       isolate(),
    951       isolate()->heap()->AllocateMap(type, instance_size, elements_kind),
    952       Map);
    953 }
    954 
    955 
    956 Handle<JSObject> Factory::CopyJSObject(Handle<JSObject> object) {
    957   CALL_HEAP_FUNCTION(isolate(),
    958                      isolate()->heap()->CopyJSObject(*object, NULL),
    959                      JSObject);
    960 }
    961 
    962 
    963 Handle<JSObject> Factory::CopyJSObjectWithAllocationSite(
    964     Handle<JSObject> object,
    965     Handle<AllocationSite> site) {
    966   CALL_HEAP_FUNCTION(isolate(),
    967                      isolate()->heap()->CopyJSObject(
    968                          *object,
    969                          site.is_null() ? NULL : *site),
    970                      JSObject);
    971 }
    972 
    973 
    974 Handle<FixedArray> Factory::CopyFixedArrayWithMap(Handle<FixedArray> array,
    975                                                   Handle<Map> map) {
    976   CALL_HEAP_FUNCTION(isolate(),
    977                      isolate()->heap()->CopyFixedArrayWithMap(*array, *map),
    978                      FixedArray);
    979 }
    980 
    981 
    982 Handle<FixedArray> Factory::CopyFixedArray(Handle<FixedArray> array) {
    983   CALL_HEAP_FUNCTION(isolate(),
    984                      isolate()->heap()->CopyFixedArray(*array),
    985                      FixedArray);
    986 }
    987 
    988 
    989 Handle<FixedArray> Factory::CopyAndTenureFixedCOWArray(
    990     Handle<FixedArray> array) {
    991   DCHECK(isolate()->heap()->InNewSpace(*array));
    992   CALL_HEAP_FUNCTION(isolate(),
    993                      isolate()->heap()->CopyAndTenureFixedCOWArray(*array),
    994                      FixedArray);
    995 }
    996 
    997 
    998 Handle<FixedDoubleArray> Factory::CopyFixedDoubleArray(
    999     Handle<FixedDoubleArray> array) {
   1000   CALL_HEAP_FUNCTION(isolate(),
   1001                      isolate()->heap()->CopyFixedDoubleArray(*array),
   1002                      FixedDoubleArray);
   1003 }
   1004 
   1005 
   1006 Handle<ConstantPoolArray> Factory::CopyConstantPoolArray(
   1007     Handle<ConstantPoolArray> array) {
   1008   CALL_HEAP_FUNCTION(isolate(),
   1009                      isolate()->heap()->CopyConstantPoolArray(*array),
   1010                      ConstantPoolArray);
   1011 }
   1012 
   1013 
   1014 Handle<Object> Factory::NewNumber(double value,
   1015                                   PretenureFlag pretenure) {
   1016   // We need to distinguish the minus zero value and this cannot be
   1017   // done after conversion to int. Doing this by comparing bit
   1018   // patterns is faster than using fpclassify() et al.
   1019   if (IsMinusZero(value)) return NewHeapNumber(-0.0, IMMUTABLE, pretenure);
   1020 
   1021   int int_value = FastD2I(value);
   1022   if (value == int_value && Smi::IsValid(int_value)) {
   1023     return handle(Smi::FromInt(int_value), isolate());
   1024   }
   1025 
   1026   // Materialize the value in the heap.
   1027   return NewHeapNumber(value, IMMUTABLE, pretenure);
   1028 }
   1029 
   1030 
   1031 Handle<Object> Factory::NewNumberFromInt(int32_t value,
   1032                                          PretenureFlag pretenure) {
   1033   if (Smi::IsValid(value)) return handle(Smi::FromInt(value), isolate());
   1034   // Bypass NewNumber to avoid various redundant checks.
   1035   return NewHeapNumber(FastI2D(value), IMMUTABLE, pretenure);
   1036 }
   1037 
   1038 
   1039 Handle<Object> Factory::NewNumberFromUint(uint32_t value,
   1040                                           PretenureFlag pretenure) {
   1041   int32_t int32v = static_cast<int32_t>(value);
   1042   if (int32v >= 0 && Smi::IsValid(int32v)) {
   1043     return handle(Smi::FromInt(int32v), isolate());
   1044   }
   1045   return NewHeapNumber(FastUI2D(value), IMMUTABLE, pretenure);
   1046 }
   1047 
   1048 
   1049 Handle<HeapNumber> Factory::NewHeapNumber(double value,
   1050                                           MutableMode mode,
   1051                                           PretenureFlag pretenure) {
   1052   CALL_HEAP_FUNCTION(
   1053       isolate(),
   1054       isolate()->heap()->AllocateHeapNumber(value, mode, pretenure),
   1055       HeapNumber);
   1056 }
   1057 
   1058 
   1059 MaybeHandle<Object> Factory::NewTypeError(const char* message,
   1060                                           Vector<Handle<Object> > args) {
   1061   return NewError("MakeTypeError", message, args);
   1062 }
   1063 
   1064 
   1065 MaybeHandle<Object> Factory::NewTypeError(Handle<String> message) {
   1066   return NewError("$TypeError", message);
   1067 }
   1068 
   1069 
   1070 MaybeHandle<Object> Factory::NewRangeError(const char* message,
   1071                                            Vector<Handle<Object> > args) {
   1072   return NewError("MakeRangeError", message, args);
   1073 }
   1074 
   1075 
   1076 MaybeHandle<Object> Factory::NewRangeError(Handle<String> message) {
   1077   return NewError("$RangeError", message);
   1078 }
   1079 
   1080 
   1081 MaybeHandle<Object> Factory::NewSyntaxError(const char* message,
   1082                                             Handle<JSArray> args) {
   1083   return NewError("MakeSyntaxError", message, args);
   1084 }
   1085 
   1086 
   1087 MaybeHandle<Object> Factory::NewSyntaxError(Handle<String> message) {
   1088   return NewError("$SyntaxError", message);
   1089 }
   1090 
   1091 
   1092 MaybeHandle<Object> Factory::NewReferenceError(const char* message,
   1093                                                Vector<Handle<Object> > args) {
   1094   return NewError("MakeReferenceError", message, args);
   1095 }
   1096 
   1097 
   1098 MaybeHandle<Object> Factory::NewReferenceError(const char* message,
   1099                                                Handle<JSArray> args) {
   1100   return NewError("MakeReferenceError", message, args);
   1101 }
   1102 
   1103 
   1104 MaybeHandle<Object> Factory::NewReferenceError(Handle<String> message) {
   1105   return NewError("$ReferenceError", message);
   1106 }
   1107 
   1108 
   1109 MaybeHandle<Object> Factory::NewError(const char* maker, const char* message,
   1110                                       Vector<Handle<Object> > args) {
   1111   // Instantiate a closeable HandleScope for EscapeFrom.
   1112   v8::EscapableHandleScope scope(reinterpret_cast<v8::Isolate*>(isolate()));
   1113   Handle<FixedArray> array = NewFixedArray(args.length());
   1114   for (int i = 0; i < args.length(); i++) {
   1115     array->set(i, *args[i]);
   1116   }
   1117   Handle<JSArray> object = NewJSArrayWithElements(array);
   1118   Handle<Object> result;
   1119   ASSIGN_RETURN_ON_EXCEPTION(isolate(), result,
   1120                              NewError(maker, message, object), Object);
   1121   return result.EscapeFrom(&scope);
   1122 }
   1123 
   1124 
   1125 MaybeHandle<Object> Factory::NewEvalError(const char* message,
   1126                                           Vector<Handle<Object> > args) {
   1127   return NewError("MakeEvalError", message, args);
   1128 }
   1129 
   1130 
   1131 MaybeHandle<Object> Factory::NewError(const char* message,
   1132                                       Vector<Handle<Object> > args) {
   1133   return NewError("MakeError", message, args);
   1134 }
   1135 
   1136 
   1137 Handle<String> Factory::EmergencyNewError(const char* message,
   1138                                           Handle<JSArray> args) {
   1139   const int kBufferSize = 1000;
   1140   char buffer[kBufferSize];
   1141   size_t space = kBufferSize;
   1142   char* p = &buffer[0];
   1143 
   1144   Vector<char> v(buffer, kBufferSize);
   1145   StrNCpy(v, message, space);
   1146   space -= Min(space, strlen(message));
   1147   p = &buffer[kBufferSize] - space;
   1148 
   1149   for (int i = 0; i < Smi::cast(args->length())->value(); i++) {
   1150     if (space > 0) {
   1151       *p++ = ' ';
   1152       space--;
   1153       if (space > 0) {
   1154         Handle<String> arg_str = Handle<String>::cast(
   1155             Object::GetElement(isolate(), args, i).ToHandleChecked());
   1156         SmartArrayPointer<char> arg = arg_str->ToCString();
   1157         Vector<char> v2(p, static_cast<int>(space));
   1158         StrNCpy(v2, arg.get(), space);
   1159         space -= Min(space, strlen(arg.get()));
   1160         p = &buffer[kBufferSize] - space;
   1161       }
   1162     }
   1163   }
   1164   if (space > 0) {
   1165     *p = '\0';
   1166   } else {
   1167     buffer[kBufferSize - 1] = '\0';
   1168   }
   1169   return NewStringFromUtf8(CStrVector(buffer), TENURED).ToHandleChecked();
   1170 }
   1171 
   1172 
   1173 MaybeHandle<Object> Factory::NewError(const char* maker, const char* message,
   1174                                       Handle<JSArray> args) {
   1175   Handle<String> make_str = InternalizeUtf8String(maker);
   1176   Handle<Object> fun_obj = Object::GetProperty(
   1177       isolate()->js_builtins_object(), make_str).ToHandleChecked();
   1178   // If the builtins haven't been properly configured yet this error
   1179   // constructor may not have been defined.  Bail out.
   1180   if (!fun_obj->IsJSFunction()) {
   1181     return EmergencyNewError(message, args);
   1182   }
   1183   Handle<JSFunction> fun = Handle<JSFunction>::cast(fun_obj);
   1184   Handle<Object> message_obj = InternalizeUtf8String(message);
   1185   Handle<Object> argv[] = { message_obj, args };
   1186 
   1187   // Invoke the JavaScript factory method. If an exception is thrown while
   1188   // running the factory method, use the exception as the result.
   1189   Handle<Object> result;
   1190   MaybeHandle<Object> exception;
   1191   if (!Execution::TryCall(fun,
   1192                           isolate()->js_builtins_object(),
   1193                           arraysize(argv),
   1194                           argv,
   1195                           &exception).ToHandle(&result)) {
   1196     return exception;
   1197   }
   1198   return result;
   1199 }
   1200 
   1201 
   1202 MaybeHandle<Object> Factory::NewError(Handle<String> message) {
   1203   return NewError("$Error", message);
   1204 }
   1205 
   1206 
   1207 MaybeHandle<Object> Factory::NewError(const char* constructor,
   1208                                       Handle<String> message) {
   1209   Handle<String> constr = InternalizeUtf8String(constructor);
   1210   Handle<JSFunction> fun = Handle<JSFunction>::cast(Object::GetProperty(
   1211       isolate()->js_builtins_object(), constr).ToHandleChecked());
   1212   Handle<Object> argv[] = { message };
   1213 
   1214   // Invoke the JavaScript factory method. If an exception is thrown while
   1215   // running the factory method, use the exception as the result.
   1216   Handle<Object> result;
   1217   MaybeHandle<Object> exception;
   1218   if (!Execution::TryCall(fun,
   1219                           isolate()->js_builtins_object(),
   1220                           arraysize(argv),
   1221                           argv,
   1222                           &exception).ToHandle(&result)) {
   1223     return exception;
   1224   }
   1225   return result;
   1226 }
   1227 
   1228 
   1229 void Factory::InitializeFunction(Handle<JSFunction> function,
   1230                                  Handle<SharedFunctionInfo> info,
   1231                                  Handle<Context> context) {
   1232   function->initialize_properties();
   1233   function->initialize_elements();
   1234   function->set_shared(*info);
   1235   function->set_code(info->code());
   1236   function->set_context(*context);
   1237   function->set_prototype_or_initial_map(*the_hole_value());
   1238   function->set_literals_or_bindings(*empty_fixed_array());
   1239   function->set_next_function_link(*undefined_value());
   1240 }
   1241 
   1242 
   1243 Handle<JSFunction> Factory::NewFunction(Handle<Map> map,
   1244                                         Handle<SharedFunctionInfo> info,
   1245                                         Handle<Context> context,
   1246                                         PretenureFlag pretenure) {
   1247   AllocationSpace space = pretenure == TENURED ? OLD_POINTER_SPACE : NEW_SPACE;
   1248   Handle<JSFunction> result = New<JSFunction>(map, space);
   1249   InitializeFunction(result, info, context);
   1250   return result;
   1251 }
   1252 
   1253 
   1254 Handle<JSFunction> Factory::NewFunction(Handle<Map> map,
   1255                                         Handle<String> name,
   1256                                         MaybeHandle<Code> code) {
   1257   Handle<Context> context(isolate()->native_context());
   1258   Handle<SharedFunctionInfo> info = NewSharedFunctionInfo(name, code);
   1259   DCHECK((info->strict_mode() == SLOPPY) &&
   1260          (map.is_identical_to(isolate()->sloppy_function_map()) ||
   1261           map.is_identical_to(
   1262               isolate()->sloppy_function_without_prototype_map()) ||
   1263           map.is_identical_to(
   1264               isolate()->sloppy_function_with_readonly_prototype_map())));
   1265   return NewFunction(map, info, context);
   1266 }
   1267 
   1268 
   1269 Handle<JSFunction> Factory::NewFunction(Handle<String> name) {
   1270   return NewFunction(
   1271       isolate()->sloppy_function_map(), name, MaybeHandle<Code>());
   1272 }
   1273 
   1274 
   1275 Handle<JSFunction> Factory::NewFunctionWithoutPrototype(Handle<String> name,
   1276                                                         Handle<Code> code) {
   1277   return NewFunction(
   1278       isolate()->sloppy_function_without_prototype_map(), name, code);
   1279 }
   1280 
   1281 
   1282 Handle<JSFunction> Factory::NewFunction(Handle<String> name,
   1283                                         Handle<Code> code,
   1284                                         Handle<Object> prototype,
   1285                                         bool read_only_prototype) {
   1286   Handle<Map> map = read_only_prototype
   1287       ? isolate()->sloppy_function_with_readonly_prototype_map()
   1288       : isolate()->sloppy_function_map();
   1289   Handle<JSFunction> result = NewFunction(map, name, code);
   1290   result->set_prototype_or_initial_map(*prototype);
   1291   return result;
   1292 }
   1293 
   1294 
   1295 Handle<JSFunction> Factory::NewFunction(Handle<String> name,
   1296                                         Handle<Code> code,
   1297                                         Handle<Object> prototype,
   1298                                         InstanceType type,
   1299                                         int instance_size,
   1300                                         bool read_only_prototype) {
   1301   // Allocate the function
   1302   Handle<JSFunction> function = NewFunction(
   1303       name, code, prototype, read_only_prototype);
   1304 
   1305   Handle<Map> initial_map = NewMap(
   1306       type, instance_size, GetInitialFastElementsKind());
   1307   if (prototype->IsTheHole() && !function->shared()->is_generator()) {
   1308     prototype = NewFunctionPrototype(function);
   1309   }
   1310 
   1311   JSFunction::SetInitialMap(function, initial_map,
   1312                             Handle<JSReceiver>::cast(prototype));
   1313 
   1314   return function;
   1315 }
   1316 
   1317 
   1318 Handle<JSFunction> Factory::NewFunction(Handle<String> name,
   1319                                         Handle<Code> code,
   1320                                         InstanceType type,
   1321                                         int instance_size) {
   1322   return NewFunction(name, code, the_hole_value(), type, instance_size);
   1323 }
   1324 
   1325 
   1326 Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {
   1327   // Make sure to use globals from the function's context, since the function
   1328   // can be from a different context.
   1329   Handle<Context> native_context(function->context()->native_context());
   1330   Handle<Map> new_map;
   1331   if (function->shared()->is_generator()) {
   1332     // Generator prototypes can share maps since they don't have "constructor"
   1333     // properties.
   1334     new_map = handle(native_context->generator_object_prototype_map());
   1335   } else {
   1336     // Each function prototype gets a fresh map to avoid unwanted sharing of
   1337     // maps between prototypes of different constructors.
   1338     Handle<JSFunction> object_function(native_context->object_function());
   1339     DCHECK(object_function->has_initial_map());
   1340     new_map = handle(object_function->initial_map());
   1341   }
   1342 
   1343   DCHECK(!new_map->is_prototype_map());
   1344   Handle<JSObject> prototype = NewJSObjectFromMap(new_map);
   1345 
   1346   if (!function->shared()->is_generator()) {
   1347     JSObject::AddProperty(prototype, constructor_string(), function, DONT_ENUM);
   1348   }
   1349 
   1350   return prototype;
   1351 }
   1352 
   1353 
   1354 Handle<JSFunction> Factory::NewFunctionFromSharedFunctionInfo(
   1355     Handle<SharedFunctionInfo> info,
   1356     Handle<Context> context,
   1357     PretenureFlag pretenure) {
   1358   int map_index = Context::FunctionMapIndex(info->strict_mode(), info->kind());
   1359   Handle<Map> map(Map::cast(context->native_context()->get(map_index)));
   1360   Handle<JSFunction> result = NewFunction(map, info, context, pretenure);
   1361 
   1362   if (info->ic_age() != isolate()->heap()->global_ic_age()) {
   1363     info->ResetForNewContext(isolate()->heap()->global_ic_age());
   1364   }
   1365 
   1366   int index = info->SearchOptimizedCodeMap(context->native_context(),
   1367                                            BailoutId::None());
   1368   if (!info->bound() && index < 0) {
   1369     int number_of_literals = info->num_literals();
   1370     Handle<FixedArray> literals = NewFixedArray(number_of_literals, pretenure);
   1371     if (number_of_literals > 0) {
   1372       // Store the native context in the literals array prefix. This
   1373       // context will be used when creating object, regexp and array
   1374       // literals in this function.
   1375       literals->set(JSFunction::kLiteralNativeContextIndex,
   1376                     context->native_context());
   1377     }
   1378     result->set_literals(*literals);
   1379   }
   1380 
   1381   if (index > 0) {
   1382     // Caching of optimized code enabled and optimized code found.
   1383     FixedArray* literals = info->GetLiteralsFromOptimizedCodeMap(index);
   1384     if (literals != NULL) result->set_literals(literals);
   1385     Code* code = info->GetCodeFromOptimizedCodeMap(index);
   1386     DCHECK(!code->marked_for_deoptimization());
   1387     result->ReplaceCode(code);
   1388     return result;
   1389   }
   1390 
   1391   if (isolate()->use_crankshaft() &&
   1392       FLAG_always_opt &&
   1393       result->is_compiled() &&
   1394       !info->is_toplevel() &&
   1395       info->allows_lazy_compilation() &&
   1396       !info->optimization_disabled() &&
   1397       !isolate()->DebuggerHasBreakPoints()) {
   1398     result->MarkForOptimization();
   1399   }
   1400   return result;
   1401 }
   1402 
   1403 
   1404 Handle<ScopeInfo> Factory::NewScopeInfo(int length) {
   1405   Handle<FixedArray> array = NewFixedArray(length, TENURED);
   1406   array->set_map_no_write_barrier(*scope_info_map());
   1407   Handle<ScopeInfo> scope_info = Handle<ScopeInfo>::cast(array);
   1408   return scope_info;
   1409 }
   1410 
   1411 
   1412 Handle<JSObject> Factory::NewExternal(void* value) {
   1413   Handle<Foreign> foreign = NewForeign(static_cast<Address>(value));
   1414   Handle<JSObject> external = NewJSObjectFromMap(external_map());
   1415   external->SetInternalField(0, *foreign);
   1416   return external;
   1417 }
   1418 
   1419 
   1420 Handle<Code> Factory::NewCodeRaw(int object_size, bool immovable) {
   1421   CALL_HEAP_FUNCTION(isolate(),
   1422                      isolate()->heap()->AllocateCode(object_size, immovable),
   1423                      Code);
   1424 }
   1425 
   1426 
   1427 Handle<Code> Factory::NewCode(const CodeDesc& desc,
   1428                               Code::Flags flags,
   1429                               Handle<Object> self_ref,
   1430                               bool immovable,
   1431                               bool crankshafted,
   1432                               int prologue_offset,
   1433                               bool is_debug) {
   1434   Handle<ByteArray> reloc_info = NewByteArray(desc.reloc_size, TENURED);
   1435   Handle<ConstantPoolArray> constant_pool =
   1436       desc.origin->NewConstantPool(isolate());
   1437 
   1438   // Compute size.
   1439   int body_size = RoundUp(desc.instr_size, kObjectAlignment);
   1440   int obj_size = Code::SizeFor(body_size);
   1441 
   1442   Handle<Code> code = NewCodeRaw(obj_size, immovable);
   1443   DCHECK(isolate()->code_range() == NULL ||
   1444          !isolate()->code_range()->valid() ||
   1445          isolate()->code_range()->contains(code->address()));
   1446 
   1447   // The code object has not been fully initialized yet.  We rely on the
   1448   // fact that no allocation will happen from this point on.
   1449   DisallowHeapAllocation no_gc;
   1450   code->set_gc_metadata(Smi::FromInt(0));
   1451   code->set_ic_age(isolate()->heap()->global_ic_age());
   1452   code->set_instruction_size(desc.instr_size);
   1453   code->set_relocation_info(*reloc_info);
   1454   code->set_flags(flags);
   1455   code->set_raw_kind_specific_flags1(0);
   1456   code->set_raw_kind_specific_flags2(0);
   1457   code->set_is_crankshafted(crankshafted);
   1458   code->set_deoptimization_data(*empty_fixed_array(), SKIP_WRITE_BARRIER);
   1459   code->set_raw_type_feedback_info(Smi::FromInt(0));
   1460   code->set_next_code_link(*undefined_value());
   1461   code->set_handler_table(*empty_fixed_array(), SKIP_WRITE_BARRIER);
   1462   code->set_prologue_offset(prologue_offset);
   1463   if (code->kind() == Code::OPTIMIZED_FUNCTION) {
   1464     code->set_marked_for_deoptimization(false);
   1465   }
   1466 
   1467   if (is_debug) {
   1468     DCHECK(code->kind() == Code::FUNCTION);
   1469     code->set_has_debug_break_slots(true);
   1470   }
   1471 
   1472   desc.origin->PopulateConstantPool(*constant_pool);
   1473   code->set_constant_pool(*constant_pool);
   1474 
   1475   // Allow self references to created code object by patching the handle to
   1476   // point to the newly allocated Code object.
   1477   if (!self_ref.is_null()) *(self_ref.location()) = *code;
   1478 
   1479   // Migrate generated code.
   1480   // The generated code can contain Object** values (typically from handles)
   1481   // that are dereferenced during the copy to point directly to the actual heap
   1482   // objects. These pointers can include references to the code object itself,
   1483   // through the self_reference parameter.
   1484   code->CopyFrom(desc);
   1485 
   1486 #ifdef VERIFY_HEAP
   1487   if (FLAG_verify_heap) code->ObjectVerify();
   1488 #endif
   1489   return code;
   1490 }
   1491 
   1492 
   1493 Handle<Code> Factory::CopyCode(Handle<Code> code) {
   1494   CALL_HEAP_FUNCTION(isolate(),
   1495                      isolate()->heap()->CopyCode(*code),
   1496                      Code);
   1497 }
   1498 
   1499 
   1500 Handle<Code> Factory::CopyCode(Handle<Code> code, Vector<byte> reloc_info) {
   1501   CALL_HEAP_FUNCTION(isolate(),
   1502                      isolate()->heap()->CopyCode(*code, reloc_info),
   1503                      Code);
   1504 }
   1505 
   1506 
   1507 Handle<JSObject> Factory::NewJSObject(Handle<JSFunction> constructor,
   1508                                       PretenureFlag pretenure) {
   1509   JSFunction::EnsureHasInitialMap(constructor);
   1510   CALL_HEAP_FUNCTION(
   1511       isolate(),
   1512       isolate()->heap()->AllocateJSObject(*constructor, pretenure), JSObject);
   1513 }
   1514 
   1515 
   1516 Handle<JSObject> Factory::NewJSObjectWithMemento(
   1517     Handle<JSFunction> constructor,
   1518     Handle<AllocationSite> site) {
   1519   JSFunction::EnsureHasInitialMap(constructor);
   1520   CALL_HEAP_FUNCTION(
   1521       isolate(),
   1522       isolate()->heap()->AllocateJSObject(*constructor, NOT_TENURED, *site),
   1523       JSObject);
   1524 }
   1525 
   1526 
   1527 Handle<JSModule> Factory::NewJSModule(Handle<Context> context,
   1528                                       Handle<ScopeInfo> scope_info) {
   1529   // Allocate a fresh map. Modules do not have a prototype.
   1530   Handle<Map> map = NewMap(JS_MODULE_TYPE, JSModule::kSize);
   1531   // Allocate the object based on the map.
   1532   Handle<JSModule> module =
   1533       Handle<JSModule>::cast(NewJSObjectFromMap(map, TENURED));
   1534   module->set_context(*context);
   1535   module->set_scope_info(*scope_info);
   1536   return module;
   1537 }
   1538 
   1539 
   1540 Handle<GlobalObject> Factory::NewGlobalObject(Handle<JSFunction> constructor) {
   1541   DCHECK(constructor->has_initial_map());
   1542   Handle<Map> map(constructor->initial_map());
   1543   DCHECK(map->is_dictionary_map());
   1544 
   1545   // Make sure no field properties are described in the initial map.
   1546   // This guarantees us that normalizing the properties does not
   1547   // require us to change property values to PropertyCells.
   1548   DCHECK(map->NextFreePropertyIndex() == 0);
   1549 
   1550   // Make sure we don't have a ton of pre-allocated slots in the
   1551   // global objects. They will be unused once we normalize the object.
   1552   DCHECK(map->unused_property_fields() == 0);
   1553   DCHECK(map->inobject_properties() == 0);
   1554 
   1555   // Initial size of the backing store to avoid resize of the storage during
   1556   // bootstrapping. The size differs between the JS global object ad the
   1557   // builtins object.
   1558   int initial_size = map->instance_type() == JS_GLOBAL_OBJECT_TYPE ? 64 : 512;
   1559 
   1560   // Allocate a dictionary object for backing storage.
   1561   int at_least_space_for = map->NumberOfOwnDescriptors() * 2 + initial_size;
   1562   Handle<NameDictionary> dictionary =
   1563       NameDictionary::New(isolate(), at_least_space_for);
   1564 
   1565   // The global object might be created from an object template with accessors.
   1566   // Fill these accessors into the dictionary.
   1567   Handle<DescriptorArray> descs(map->instance_descriptors());
   1568   for (int i = 0; i < map->NumberOfOwnDescriptors(); i++) {
   1569     PropertyDetails details = descs->GetDetails(i);
   1570     DCHECK(details.type() == CALLBACKS);  // Only accessors are expected.
   1571     PropertyDetails d = PropertyDetails(details.attributes(), CALLBACKS, i + 1);
   1572     Handle<Name> name(descs->GetKey(i));
   1573     Handle<Object> value(descs->GetCallbacksObject(i), isolate());
   1574     Handle<PropertyCell> cell = NewPropertyCell(value);
   1575     // |dictionary| already contains enough space for all properties.
   1576     USE(NameDictionary::Add(dictionary, name, cell, d));
   1577   }
   1578 
   1579   // Allocate the global object and initialize it with the backing store.
   1580   Handle<GlobalObject> global = New<GlobalObject>(map, OLD_POINTER_SPACE);
   1581   isolate()->heap()->InitializeJSObjectFromMap(*global, *dictionary, *map);
   1582 
   1583   // Create a new map for the global object.
   1584   Handle<Map> new_map = Map::CopyDropDescriptors(map);
   1585   new_map->set_dictionary_map(true);
   1586 
   1587   // Set up the global object as a normalized object.
   1588   global->set_map(*new_map);
   1589   global->set_properties(*dictionary);
   1590 
   1591   // Make sure result is a global object with properties in dictionary.
   1592   DCHECK(global->IsGlobalObject() && !global->HasFastProperties());
   1593   return global;
   1594 }
   1595 
   1596 
   1597 Handle<JSObject> Factory::NewJSObjectFromMap(
   1598     Handle<Map> map,
   1599     PretenureFlag pretenure,
   1600     bool alloc_props,
   1601     Handle<AllocationSite> allocation_site) {
   1602   CALL_HEAP_FUNCTION(
   1603       isolate(),
   1604       isolate()->heap()->AllocateJSObjectFromMap(
   1605           *map,
   1606           pretenure,
   1607           alloc_props,
   1608           allocation_site.is_null() ? NULL : *allocation_site),
   1609       JSObject);
   1610 }
   1611 
   1612 
   1613 Handle<JSArray> Factory::NewJSArray(ElementsKind elements_kind,
   1614                                     PretenureFlag pretenure) {
   1615   Context* native_context = isolate()->context()->native_context();
   1616   JSFunction* array_function = native_context->array_function();
   1617   Map* map = array_function->initial_map();
   1618   Map* transition_map = isolate()->get_initial_js_array_map(elements_kind);
   1619   if (transition_map != NULL) map = transition_map;
   1620   return Handle<JSArray>::cast(NewJSObjectFromMap(handle(map), pretenure));
   1621 }
   1622 
   1623 
   1624 Handle<JSArray> Factory::NewJSArray(ElementsKind elements_kind,
   1625                                     int length,
   1626                                     int capacity,
   1627                                     ArrayStorageAllocationMode mode,
   1628                                     PretenureFlag pretenure) {
   1629   Handle<JSArray> array = NewJSArray(elements_kind, pretenure);
   1630   NewJSArrayStorage(array, length, capacity, mode);
   1631   return array;
   1632 }
   1633 
   1634 
   1635 Handle<JSArray> Factory::NewJSArrayWithElements(Handle<FixedArrayBase> elements,
   1636                                                 ElementsKind elements_kind,
   1637                                                 int length,
   1638                                                 PretenureFlag pretenure) {
   1639   DCHECK(length <= elements->length());
   1640   Handle<JSArray> array = NewJSArray(elements_kind, pretenure);
   1641 
   1642   array->set_elements(*elements);
   1643   array->set_length(Smi::FromInt(length));
   1644   JSObject::ValidateElements(array);
   1645   return array;
   1646 }
   1647 
   1648 
   1649 void Factory::NewJSArrayStorage(Handle<JSArray> array,
   1650                                 int length,
   1651                                 int capacity,
   1652                                 ArrayStorageAllocationMode mode) {
   1653   DCHECK(capacity >= length);
   1654 
   1655   if (capacity == 0) {
   1656     array->set_length(Smi::FromInt(0));
   1657     array->set_elements(*empty_fixed_array());
   1658     return;
   1659   }
   1660 
   1661   Handle<FixedArrayBase> elms;
   1662   ElementsKind elements_kind = array->GetElementsKind();
   1663   if (IsFastDoubleElementsKind(elements_kind)) {
   1664     if (mode == DONT_INITIALIZE_ARRAY_ELEMENTS) {
   1665       elms = NewFixedDoubleArray(capacity);
   1666     } else {
   1667       DCHECK(mode == INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE);
   1668       elms = NewFixedDoubleArrayWithHoles(capacity);
   1669     }
   1670   } else {
   1671     DCHECK(IsFastSmiOrObjectElementsKind(elements_kind));
   1672     if (mode == DONT_INITIALIZE_ARRAY_ELEMENTS) {
   1673       elms = NewUninitializedFixedArray(capacity);
   1674     } else {
   1675       DCHECK(mode == INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE);
   1676       elms = NewFixedArrayWithHoles(capacity);
   1677     }
   1678   }
   1679 
   1680   array->set_elements(*elms);
   1681   array->set_length(Smi::FromInt(length));
   1682 }
   1683 
   1684 
   1685 Handle<JSGeneratorObject> Factory::NewJSGeneratorObject(
   1686     Handle<JSFunction> function) {
   1687   DCHECK(function->shared()->is_generator());
   1688   JSFunction::EnsureHasInitialMap(function);
   1689   Handle<Map> map(function->initial_map());
   1690   DCHECK(map->instance_type() == JS_GENERATOR_OBJECT_TYPE);
   1691   CALL_HEAP_FUNCTION(
   1692       isolate(),
   1693       isolate()->heap()->AllocateJSObjectFromMap(*map),
   1694       JSGeneratorObject);
   1695 }
   1696 
   1697 
   1698 Handle<JSArrayBuffer> Factory::NewJSArrayBuffer() {
   1699   Handle<JSFunction> array_buffer_fun(
   1700       isolate()->native_context()->array_buffer_fun());
   1701   CALL_HEAP_FUNCTION(
   1702       isolate(),
   1703       isolate()->heap()->AllocateJSObject(*array_buffer_fun),
   1704       JSArrayBuffer);
   1705 }
   1706 
   1707 
   1708 Handle<JSDataView> Factory::NewJSDataView() {
   1709   Handle<JSFunction> data_view_fun(
   1710       isolate()->native_context()->data_view_fun());
   1711   CALL_HEAP_FUNCTION(
   1712       isolate(),
   1713       isolate()->heap()->AllocateJSObject(*data_view_fun),
   1714       JSDataView);
   1715 }
   1716 
   1717 
   1718 static JSFunction* GetTypedArrayFun(ExternalArrayType type,
   1719                                     Isolate* isolate) {
   1720   Context* native_context = isolate->context()->native_context();
   1721   switch (type) {
   1722 #define TYPED_ARRAY_FUN(Type, type, TYPE, ctype, size)                        \
   1723     case kExternal##Type##Array:                                              \
   1724       return native_context->type##_array_fun();
   1725 
   1726     TYPED_ARRAYS(TYPED_ARRAY_FUN)
   1727 #undef TYPED_ARRAY_FUN
   1728 
   1729     default:
   1730       UNREACHABLE();
   1731       return NULL;
   1732   }
   1733 }
   1734 
   1735 
   1736 Handle<JSTypedArray> Factory::NewJSTypedArray(ExternalArrayType type) {
   1737   Handle<JSFunction> typed_array_fun_handle(GetTypedArrayFun(type, isolate()));
   1738 
   1739   CALL_HEAP_FUNCTION(
   1740       isolate(),
   1741       isolate()->heap()->AllocateJSObject(*typed_array_fun_handle),
   1742       JSTypedArray);
   1743 }
   1744 
   1745 
   1746 Handle<JSProxy> Factory::NewJSProxy(Handle<Object> handler,
   1747                                     Handle<Object> prototype) {
   1748   // Allocate map.
   1749   // TODO(rossberg): Once we optimize proxies, think about a scheme to share
   1750   // maps. Will probably depend on the identity of the handler object, too.
   1751   Handle<Map> map = NewMap(JS_PROXY_TYPE, JSProxy::kSize);
   1752   map->set_prototype(*prototype);
   1753 
   1754   // Allocate the proxy object.
   1755   Handle<JSProxy> result = New<JSProxy>(map, NEW_SPACE);
   1756   result->InitializeBody(map->instance_size(), Smi::FromInt(0));
   1757   result->set_handler(*handler);
   1758   result->set_hash(*undefined_value(), SKIP_WRITE_BARRIER);
   1759   return result;
   1760 }
   1761 
   1762 
   1763 Handle<JSProxy> Factory::NewJSFunctionProxy(Handle<Object> handler,
   1764                                             Handle<Object> call_trap,
   1765                                             Handle<Object> construct_trap,
   1766                                             Handle<Object> prototype) {
   1767   // Allocate map.
   1768   // TODO(rossberg): Once we optimize proxies, think about a scheme to share
   1769   // maps. Will probably depend on the identity of the handler object, too.
   1770   Handle<Map> map = NewMap(JS_FUNCTION_PROXY_TYPE, JSFunctionProxy::kSize);
   1771   map->set_prototype(*prototype);
   1772 
   1773   // Allocate the proxy object.
   1774   Handle<JSFunctionProxy> result = New<JSFunctionProxy>(map, NEW_SPACE);
   1775   result->InitializeBody(map->instance_size(), Smi::FromInt(0));
   1776   result->set_handler(*handler);
   1777   result->set_hash(*undefined_value(), SKIP_WRITE_BARRIER);
   1778   result->set_call_trap(*call_trap);
   1779   result->set_construct_trap(*construct_trap);
   1780   return result;
   1781 }
   1782 
   1783 
   1784 void Factory::ReinitializeJSProxy(Handle<JSProxy> proxy, InstanceType type,
   1785                                   int size) {
   1786   DCHECK(type == JS_OBJECT_TYPE || type == JS_FUNCTION_TYPE);
   1787 
   1788   // Allocate fresh map.
   1789   // TODO(rossberg): Once we optimize proxies, cache these maps.
   1790   Handle<Map> map = NewMap(type, size);
   1791 
   1792   // Check that the receiver has at least the size of the fresh object.
   1793   int size_difference = proxy->map()->instance_size() - map->instance_size();
   1794   DCHECK(size_difference >= 0);
   1795 
   1796   map->set_prototype(proxy->map()->prototype());
   1797 
   1798   // Allocate the backing storage for the properties.
   1799   int prop_size = map->InitialPropertiesLength();
   1800   Handle<FixedArray> properties = NewFixedArray(prop_size, TENURED);
   1801 
   1802   Heap* heap = isolate()->heap();
   1803   MaybeHandle<SharedFunctionInfo> shared;
   1804   if (type == JS_FUNCTION_TYPE) {
   1805     OneByteStringKey key(STATIC_CHAR_VECTOR("<freezing call trap>"),
   1806                          heap->HashSeed());
   1807     Handle<String> name = InternalizeStringWithKey(&key);
   1808     shared = NewSharedFunctionInfo(name, MaybeHandle<Code>());
   1809   }
   1810 
   1811   // In order to keep heap in consistent state there must be no allocations
   1812   // before object re-initialization is finished and filler object is installed.
   1813   DisallowHeapAllocation no_allocation;
   1814 
   1815   // Put in filler if the new object is smaller than the old.
   1816   if (size_difference > 0) {
   1817     Address address = proxy->address();
   1818     heap->CreateFillerObjectAt(address + map->instance_size(), size_difference);
   1819     heap->AdjustLiveBytes(address, -size_difference, Heap::FROM_MUTATOR);
   1820   }
   1821 
   1822   // Reset the map for the object.
   1823   proxy->synchronized_set_map(*map);
   1824   Handle<JSObject> jsobj = Handle<JSObject>::cast(proxy);
   1825 
   1826   // Reinitialize the object from the constructor map.
   1827   heap->InitializeJSObjectFromMap(*jsobj, *properties, *map);
   1828 
   1829   // The current native context is used to set up certain bits.
   1830   // TODO(adamk): Using the current context seems wrong, it should be whatever
   1831   // context the JSProxy originated in. But that context isn't stored anywhere.
   1832   Handle<Context> context(isolate()->native_context());
   1833 
   1834   // Functions require some minimal initialization.
   1835   if (type == JS_FUNCTION_TYPE) {
   1836     map->set_function_with_prototype(true);
   1837     Handle<JSFunction> js_function = Handle<JSFunction>::cast(proxy);
   1838     InitializeFunction(js_function, shared.ToHandleChecked(), context);
   1839   } else {
   1840     // Provide JSObjects with a constructor.
   1841     map->set_constructor(context->object_function());
   1842   }
   1843 }
   1844 
   1845 
   1846 void Factory::ReinitializeJSGlobalProxy(Handle<JSGlobalProxy> object,
   1847                                         Handle<JSFunction> constructor) {
   1848   DCHECK(constructor->has_initial_map());
   1849   Handle<Map> map(constructor->initial_map(), isolate());
   1850 
   1851   // The proxy's hash should be retained across reinitialization.
   1852   Handle<Object> hash(object->hash(), isolate());
   1853 
   1854   // Check that the already allocated object has the same size and type as
   1855   // objects allocated using the constructor.
   1856   DCHECK(map->instance_size() == object->map()->instance_size());
   1857   DCHECK(map->instance_type() == object->map()->instance_type());
   1858 
   1859   // Allocate the backing storage for the properties.
   1860   int prop_size = map->InitialPropertiesLength();
   1861   Handle<FixedArray> properties = NewFixedArray(prop_size, TENURED);
   1862 
   1863   // In order to keep heap in consistent state there must be no allocations
   1864   // before object re-initialization is finished.
   1865   DisallowHeapAllocation no_allocation;
   1866 
   1867   // Reset the map for the object.
   1868   object->synchronized_set_map(*map);
   1869 
   1870   Heap* heap = isolate()->heap();
   1871   // Reinitialize the object from the constructor map.
   1872   heap->InitializeJSObjectFromMap(*object, *properties, *map);
   1873 
   1874   // Restore the saved hash.
   1875   object->set_hash(*hash);
   1876 }
   1877 
   1878 
   1879 void Factory::BecomeJSObject(Handle<JSProxy> proxy) {
   1880   ReinitializeJSProxy(proxy, JS_OBJECT_TYPE, JSObject::kHeaderSize);
   1881 }
   1882 
   1883 
   1884 void Factory::BecomeJSFunction(Handle<JSProxy> proxy) {
   1885   ReinitializeJSProxy(proxy, JS_FUNCTION_TYPE, JSFunction::kSize);
   1886 }
   1887 
   1888 
   1889 Handle<TypeFeedbackVector> Factory::NewTypeFeedbackVector(int slot_count) {
   1890   // Ensure we can skip the write barrier
   1891   DCHECK_EQ(isolate()->heap()->uninitialized_symbol(),
   1892             *TypeFeedbackVector::UninitializedSentinel(isolate()));
   1893 
   1894   if (slot_count == 0) {
   1895     return Handle<TypeFeedbackVector>::cast(empty_fixed_array());
   1896   }
   1897 
   1898   CALL_HEAP_FUNCTION(isolate(),
   1899                      isolate()->heap()->AllocateFixedArrayWithFiller(
   1900                          slot_count, TENURED,
   1901                          *TypeFeedbackVector::UninitializedSentinel(isolate())),
   1902                      TypeFeedbackVector);
   1903 }
   1904 
   1905 
   1906 Handle<SharedFunctionInfo> Factory::NewSharedFunctionInfo(
   1907     Handle<String> name, int number_of_literals, FunctionKind kind,
   1908     Handle<Code> code, Handle<ScopeInfo> scope_info,
   1909     Handle<TypeFeedbackVector> feedback_vector) {
   1910   DCHECK(IsValidFunctionKind(kind));
   1911   Handle<SharedFunctionInfo> shared = NewSharedFunctionInfo(name, code);
   1912   shared->set_scope_info(*scope_info);
   1913   shared->set_feedback_vector(*feedback_vector);
   1914   shared->set_kind(kind);
   1915   int literals_array_size = number_of_literals;
   1916   // If the function contains object, regexp or array literals,
   1917   // allocate extra space for a literals array prefix containing the
   1918   // context.
   1919   if (number_of_literals > 0) {
   1920     literals_array_size += JSFunction::kLiteralsPrefixSize;
   1921   }
   1922   shared->set_num_literals(literals_array_size);
   1923   if (IsGeneratorFunction(kind)) {
   1924     shared->set_instance_class_name(isolate()->heap()->Generator_string());
   1925     shared->DisableOptimization(kGenerator);
   1926   }
   1927   return shared;
   1928 }
   1929 
   1930 
   1931 Handle<JSMessageObject> Factory::NewJSMessageObject(
   1932     Handle<String> type,
   1933     Handle<JSArray> arguments,
   1934     int start_position,
   1935     int end_position,
   1936     Handle<Object> script,
   1937     Handle<Object> stack_frames) {
   1938   Handle<Map> map = message_object_map();
   1939   Handle<JSMessageObject> message = New<JSMessageObject>(map, NEW_SPACE);
   1940   message->set_properties(*empty_fixed_array(), SKIP_WRITE_BARRIER);
   1941   message->initialize_elements();
   1942   message->set_elements(*empty_fixed_array(), SKIP_WRITE_BARRIER);
   1943   message->set_type(*type);
   1944   message->set_arguments(*arguments);
   1945   message->set_start_position(start_position);
   1946   message->set_end_position(end_position);
   1947   message->set_script(*script);
   1948   message->set_stack_frames(*stack_frames);
   1949   return message;
   1950 }
   1951 
   1952 
   1953 Handle<SharedFunctionInfo> Factory::NewSharedFunctionInfo(
   1954     Handle<String> name,
   1955     MaybeHandle<Code> maybe_code) {
   1956   Handle<Map> map = shared_function_info_map();
   1957   Handle<SharedFunctionInfo> share = New<SharedFunctionInfo>(map,
   1958                                                              OLD_POINTER_SPACE);
   1959 
   1960   // Set pointer fields.
   1961   share->set_name(*name);
   1962   Handle<Code> code;
   1963   if (!maybe_code.ToHandle(&code)) {
   1964     code = handle(isolate()->builtins()->builtin(Builtins::kIllegal));
   1965   }
   1966   share->set_code(*code);
   1967   share->set_optimized_code_map(Smi::FromInt(0));
   1968   share->set_scope_info(ScopeInfo::Empty(isolate()));
   1969   Code* construct_stub =
   1970       isolate()->builtins()->builtin(Builtins::kJSConstructStubGeneric);
   1971   share->set_construct_stub(construct_stub);
   1972   share->set_instance_class_name(*Object_string());
   1973   share->set_function_data(*undefined_value(), SKIP_WRITE_BARRIER);
   1974   share->set_script(*undefined_value(), SKIP_WRITE_BARRIER);
   1975   share->set_debug_info(*undefined_value(), SKIP_WRITE_BARRIER);
   1976   share->set_inferred_name(*empty_string(), SKIP_WRITE_BARRIER);
   1977   Handle<TypeFeedbackVector> feedback_vector = NewTypeFeedbackVector(0);
   1978   share->set_feedback_vector(*feedback_vector, SKIP_WRITE_BARRIER);
   1979   share->set_profiler_ticks(0);
   1980   share->set_ast_node_count(0);
   1981   share->set_counters(0);
   1982 
   1983   // Set integer fields (smi or int, depending on the architecture).
   1984   share->set_length(0);
   1985   share->set_formal_parameter_count(0);
   1986   share->set_expected_nof_properties(0);
   1987   share->set_num_literals(0);
   1988   share->set_start_position_and_type(0);
   1989   share->set_end_position(0);
   1990   share->set_function_token_position(0);
   1991   // All compiler hints default to false or 0.
   1992   share->set_compiler_hints(0);
   1993   share->set_opt_count_and_bailout_reason(0);
   1994 
   1995   return share;
   1996 }
   1997 
   1998 
   1999 static inline int NumberCacheHash(Handle<FixedArray> cache,
   2000                                   Handle<Object> number) {
   2001   int mask = (cache->length() >> 1) - 1;
   2002   if (number->IsSmi()) {
   2003     return Handle<Smi>::cast(number)->value() & mask;
   2004   } else {
   2005     DoubleRepresentation rep(number->Number());
   2006     return
   2007         (static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32)) & mask;
   2008   }
   2009 }
   2010 
   2011 
   2012 Handle<Object> Factory::GetNumberStringCache(Handle<Object> number) {
   2013   DisallowHeapAllocation no_gc;
   2014   int hash = NumberCacheHash(number_string_cache(), number);
   2015   Object* key = number_string_cache()->get(hash * 2);
   2016   if (key == *number || (key->IsHeapNumber() && number->IsHeapNumber() &&
   2017                          key->Number() == number->Number())) {
   2018     return Handle<String>(
   2019         String::cast(number_string_cache()->get(hash * 2 + 1)), isolate());
   2020   }
   2021   return undefined_value();
   2022 }
   2023 
   2024 
   2025 void Factory::SetNumberStringCache(Handle<Object> number,
   2026                                    Handle<String> string) {
   2027   int hash = NumberCacheHash(number_string_cache(), number);
   2028   if (number_string_cache()->get(hash * 2) != *undefined_value()) {
   2029     int full_size = isolate()->heap()->FullSizeNumberStringCacheLength();
   2030     if (number_string_cache()->length() != full_size) {
   2031       // The first time we have a hash collision, we move to the full sized
   2032       // number string cache.  The idea is to have a small number string
   2033       // cache in the snapshot to keep  boot-time memory usage down.
   2034       // If we expand the number string cache already while creating
   2035       // the snapshot then that didn't work out.
   2036       DCHECK(!isolate()->serializer_enabled() || FLAG_extra_code != NULL);
   2037       Handle<FixedArray> new_cache = NewFixedArray(full_size, TENURED);
   2038       isolate()->heap()->set_number_string_cache(*new_cache);
   2039       return;
   2040     }
   2041   }
   2042   number_string_cache()->set(hash * 2, *number);
   2043   number_string_cache()->set(hash * 2 + 1, *string);
   2044 }
   2045 
   2046 
   2047 Handle<String> Factory::NumberToString(Handle<Object> number,
   2048                                        bool check_number_string_cache) {
   2049   isolate()->counters()->number_to_string_runtime()->Increment();
   2050   if (check_number_string_cache) {
   2051     Handle<Object> cached = GetNumberStringCache(number);
   2052     if (!cached->IsUndefined()) return Handle<String>::cast(cached);
   2053   }
   2054 
   2055   char arr[100];
   2056   Vector<char> buffer(arr, arraysize(arr));
   2057   const char* str;
   2058   if (number->IsSmi()) {
   2059     int num = Handle<Smi>::cast(number)->value();
   2060     str = IntToCString(num, buffer);
   2061   } else {
   2062     double num = Handle<HeapNumber>::cast(number)->value();
   2063     str = DoubleToCString(num, buffer);
   2064   }
   2065 
   2066   // We tenure the allocated string since it is referenced from the
   2067   // number-string cache which lives in the old space.
   2068   Handle<String> js_string = NewStringFromAsciiChecked(str, TENURED);
   2069   SetNumberStringCache(number, js_string);
   2070   return js_string;
   2071 }
   2072 
   2073 
   2074 Handle<DebugInfo> Factory::NewDebugInfo(Handle<SharedFunctionInfo> shared) {
   2075   // Get the original code of the function.
   2076   Handle<Code> code(shared->code());
   2077 
   2078   // Create a copy of the code before allocating the debug info object to avoid
   2079   // allocation while setting up the debug info object.
   2080   Handle<Code> original_code(*Factory::CopyCode(code));
   2081 
   2082   // Allocate initial fixed array for active break points before allocating the
   2083   // debug info object to avoid allocation while setting up the debug info
   2084   // object.
   2085   Handle<FixedArray> break_points(
   2086       NewFixedArray(DebugInfo::kEstimatedNofBreakPointsInFunction));
   2087 
   2088   // Create and set up the debug info object. Debug info contains function, a
   2089   // copy of the original code, the executing code and initial fixed array for
   2090   // active break points.
   2091   Handle<DebugInfo> debug_info =
   2092       Handle<DebugInfo>::cast(NewStruct(DEBUG_INFO_TYPE));
   2093   debug_info->set_shared(*shared);
   2094   debug_info->set_original_code(*original_code);
   2095   debug_info->set_code(*code);
   2096   debug_info->set_break_points(*break_points);
   2097 
   2098   // Link debug info to function.
   2099   shared->set_debug_info(*debug_info);
   2100 
   2101   return debug_info;
   2102 }
   2103 
   2104 
   2105 Handle<JSObject> Factory::NewArgumentsObject(Handle<JSFunction> callee,
   2106                                              int length) {
   2107   bool strict_mode_callee = callee->shared()->strict_mode() == STRICT;
   2108   Handle<Map> map = strict_mode_callee ? isolate()->strict_arguments_map()
   2109                                        : isolate()->sloppy_arguments_map();
   2110 
   2111   AllocationSiteUsageContext context(isolate(), Handle<AllocationSite>(),
   2112                                      false);
   2113   DCHECK(!isolate()->has_pending_exception());
   2114   Handle<JSObject> result = NewJSObjectFromMap(map);
   2115   Handle<Smi> value(Smi::FromInt(length), isolate());
   2116   Object::SetProperty(result, length_string(), value, STRICT).Assert();
   2117   if (!strict_mode_callee) {
   2118     Object::SetProperty(result, callee_string(), callee, STRICT).Assert();
   2119   }
   2120   return result;
   2121 }
   2122 
   2123 
   2124 Handle<JSFunction> Factory::CreateApiFunction(
   2125     Handle<FunctionTemplateInfo> obj,
   2126     Handle<Object> prototype,
   2127     ApiInstanceType instance_type) {
   2128   Handle<Code> code = isolate()->builtins()->HandleApiCall();
   2129   Handle<Code> construct_stub = isolate()->builtins()->JSConstructStubApi();
   2130 
   2131   Handle<JSFunction> result;
   2132   if (obj->remove_prototype()) {
   2133     result = NewFunctionWithoutPrototype(empty_string(), code);
   2134   } else {
   2135     int internal_field_count = 0;
   2136     if (!obj->instance_template()->IsUndefined()) {
   2137       Handle<ObjectTemplateInfo> instance_template =
   2138           Handle<ObjectTemplateInfo>(
   2139               ObjectTemplateInfo::cast(obj->instance_template()));
   2140       internal_field_count =
   2141           Smi::cast(instance_template->internal_field_count())->value();
   2142     }
   2143 
   2144     // TODO(svenpanne) Kill ApiInstanceType and refactor things by generalizing
   2145     // JSObject::GetHeaderSize.
   2146     int instance_size = kPointerSize * internal_field_count;
   2147     InstanceType type;
   2148     switch (instance_type) {
   2149       case JavaScriptObjectType:
   2150         type = JS_OBJECT_TYPE;
   2151         instance_size += JSObject::kHeaderSize;
   2152         break;
   2153       case GlobalObjectType:
   2154         type = JS_GLOBAL_OBJECT_TYPE;
   2155         instance_size += JSGlobalObject::kSize;
   2156         break;
   2157       case GlobalProxyType:
   2158         type = JS_GLOBAL_PROXY_TYPE;
   2159         instance_size += JSGlobalProxy::kSize;
   2160         break;
   2161       default:
   2162         UNREACHABLE();
   2163         type = JS_OBJECT_TYPE;  // Keep the compiler happy.
   2164         break;
   2165     }
   2166 
   2167     result = NewFunction(empty_string(), code, prototype, type,
   2168                          instance_size, obj->read_only_prototype());
   2169   }
   2170 
   2171   result->shared()->set_length(obj->length());
   2172   Handle<Object> class_name(obj->class_name(), isolate());
   2173   if (class_name->IsString()) {
   2174     result->shared()->set_instance_class_name(*class_name);
   2175     result->shared()->set_name(*class_name);
   2176   }
   2177   result->shared()->set_function_data(*obj);
   2178   result->shared()->set_construct_stub(*construct_stub);
   2179   result->shared()->DontAdaptArguments();
   2180 
   2181   if (obj->remove_prototype()) {
   2182     DCHECK(result->shared()->IsApiFunction());
   2183     DCHECK(!result->has_initial_map());
   2184     DCHECK(!result->has_prototype());
   2185     return result;
   2186   }
   2187 
   2188   if (prototype->IsTheHole()) {
   2189 #ifdef DEBUG
   2190     LookupIterator it(handle(JSObject::cast(result->prototype())),
   2191                       constructor_string(),
   2192                       LookupIterator::OWN_SKIP_INTERCEPTOR);
   2193     MaybeHandle<Object> maybe_prop = Object::GetProperty(&it);
   2194     DCHECK(it.IsFound());
   2195     DCHECK(maybe_prop.ToHandleChecked().is_identical_to(result));
   2196 #endif
   2197   } else {
   2198     JSObject::AddProperty(handle(JSObject::cast(result->prototype())),
   2199                           constructor_string(), result, DONT_ENUM);
   2200   }
   2201 
   2202   // Down from here is only valid for API functions that can be used as a
   2203   // constructor (don't set the "remove prototype" flag).
   2204 
   2205   Handle<Map> map(result->initial_map());
   2206 
   2207   // Mark as undetectable if needed.
   2208   if (obj->undetectable()) {
   2209     map->set_is_undetectable();
   2210   }
   2211 
   2212   // Mark as hidden for the __proto__ accessor if needed.
   2213   if (obj->hidden_prototype()) {
   2214     map->set_is_hidden_prototype();
   2215   }
   2216 
   2217   // Mark as needs_access_check if needed.
   2218   if (obj->needs_access_check()) {
   2219     map->set_is_access_check_needed(true);
   2220   }
   2221 
   2222   // Set interceptor information in the map.
   2223   if (!obj->named_property_handler()->IsUndefined()) {
   2224     map->set_has_named_interceptor();
   2225   }
   2226   if (!obj->indexed_property_handler()->IsUndefined()) {
   2227     map->set_has_indexed_interceptor();
   2228   }
   2229 
   2230   // Set instance call-as-function information in the map.
   2231   if (!obj->instance_call_handler()->IsUndefined()) {
   2232     map->set_has_instance_call_handler();
   2233   }
   2234 
   2235   // Recursively copy parent instance templates' accessors,
   2236   // 'data' may be modified.
   2237   int max_number_of_additional_properties = 0;
   2238   int max_number_of_static_properties = 0;
   2239   FunctionTemplateInfo* info = *obj;
   2240   while (true) {
   2241     if (!info->instance_template()->IsUndefined()) {
   2242       Object* props =
   2243           ObjectTemplateInfo::cast(
   2244               info->instance_template())->property_accessors();
   2245       if (!props->IsUndefined()) {
   2246         Handle<Object> props_handle(props, isolate());
   2247         NeanderArray props_array(props_handle);
   2248         max_number_of_additional_properties += props_array.length();
   2249       }
   2250     }
   2251     if (!info->property_accessors()->IsUndefined()) {
   2252       Object* props = info->property_accessors();
   2253       if (!props->IsUndefined()) {
   2254         Handle<Object> props_handle(props, isolate());
   2255         NeanderArray props_array(props_handle);
   2256         max_number_of_static_properties += props_array.length();
   2257       }
   2258     }
   2259     Object* parent = info->parent_template();
   2260     if (parent->IsUndefined()) break;
   2261     info = FunctionTemplateInfo::cast(parent);
   2262   }
   2263 
   2264   Map::EnsureDescriptorSlack(map, max_number_of_additional_properties);
   2265 
   2266   // Use a temporary FixedArray to acculumate static accessors
   2267   int valid_descriptors = 0;
   2268   Handle<FixedArray> array;
   2269   if (max_number_of_static_properties > 0) {
   2270     array = NewFixedArray(max_number_of_static_properties);
   2271   }
   2272 
   2273   while (true) {
   2274     // Install instance descriptors
   2275     if (!obj->instance_template()->IsUndefined()) {
   2276       Handle<ObjectTemplateInfo> instance =
   2277           Handle<ObjectTemplateInfo>(
   2278               ObjectTemplateInfo::cast(obj->instance_template()), isolate());
   2279       Handle<Object> props = Handle<Object>(instance->property_accessors(),
   2280                                             isolate());
   2281       if (!props->IsUndefined()) {
   2282         Map::AppendCallbackDescriptors(map, props);
   2283       }
   2284     }
   2285     // Accumulate static accessors
   2286     if (!obj->property_accessors()->IsUndefined()) {
   2287       Handle<Object> props = Handle<Object>(obj->property_accessors(),
   2288                                             isolate());
   2289       valid_descriptors =
   2290           AccessorInfo::AppendUnique(props, array, valid_descriptors);
   2291     }
   2292     // Climb parent chain
   2293     Handle<Object> parent = Handle<Object>(obj->parent_template(), isolate());
   2294     if (parent->IsUndefined()) break;
   2295     obj = Handle<FunctionTemplateInfo>::cast(parent);
   2296   }
   2297 
   2298   // Install accumulated static accessors
   2299   for (int i = 0; i < valid_descriptors; i++) {
   2300     Handle<AccessorInfo> accessor(AccessorInfo::cast(array->get(i)));
   2301     JSObject::SetAccessor(result, accessor).Assert();
   2302   }
   2303 
   2304   DCHECK(result->shared()->IsApiFunction());
   2305   return result;
   2306 }
   2307 
   2308 
   2309 Handle<MapCache> Factory::AddToMapCache(Handle<Context> context,
   2310                                         Handle<FixedArray> keys,
   2311                                         Handle<Map> map) {
   2312   Handle<MapCache> map_cache = handle(MapCache::cast(context->map_cache()));
   2313   Handle<MapCache> result = MapCache::Put(map_cache, keys, map);
   2314   context->set_map_cache(*result);
   2315   return result;
   2316 }
   2317 
   2318 
   2319 Handle<Map> Factory::ObjectLiteralMapFromCache(Handle<Context> context,
   2320                                                Handle<FixedArray> keys) {
   2321   if (context->map_cache()->IsUndefined()) {
   2322     // Allocate the new map cache for the native context.
   2323     Handle<MapCache> new_cache = MapCache::New(isolate(), 24);
   2324     context->set_map_cache(*new_cache);
   2325   }
   2326   // Check to see whether there is a matching element in the cache.
   2327   Handle<MapCache> cache =
   2328       Handle<MapCache>(MapCache::cast(context->map_cache()));
   2329   Handle<Object> result = Handle<Object>(cache->Lookup(*keys), isolate());
   2330   if (result->IsMap()) return Handle<Map>::cast(result);
   2331   int length = keys->length();
   2332   // Create a new map and add it to the cache. Reuse the initial map of the
   2333   // Object function if the literal has no predeclared properties.
   2334   Handle<Map> map = length == 0
   2335                         ? handle(context->object_function()->initial_map())
   2336                         : Map::Create(isolate(), length);
   2337   AddToMapCache(context, keys, map);
   2338   return map;
   2339 }
   2340 
   2341 
   2342 void Factory::SetRegExpAtomData(Handle<JSRegExp> regexp,
   2343                                 JSRegExp::Type type,
   2344                                 Handle<String> source,
   2345                                 JSRegExp::Flags flags,
   2346                                 Handle<Object> data) {
   2347   Handle<FixedArray> store = NewFixedArray(JSRegExp::kAtomDataSize);
   2348 
   2349   store->set(JSRegExp::kTagIndex, Smi::FromInt(type));
   2350   store->set(JSRegExp::kSourceIndex, *source);
   2351   store->set(JSRegExp::kFlagsIndex, Smi::FromInt(flags.value()));
   2352   store->set(JSRegExp::kAtomPatternIndex, *data);
   2353   regexp->set_data(*store);
   2354 }
   2355 
   2356 void Factory::SetRegExpIrregexpData(Handle<JSRegExp> regexp,
   2357                                     JSRegExp::Type type,
   2358                                     Handle<String> source,
   2359                                     JSRegExp::Flags flags,
   2360                                     int capture_count) {
   2361   Handle<FixedArray> store = NewFixedArray(JSRegExp::kIrregexpDataSize);
   2362   Smi* uninitialized = Smi::FromInt(JSRegExp::kUninitializedValue);
   2363   store->set(JSRegExp::kTagIndex, Smi::FromInt(type));
   2364   store->set(JSRegExp::kSourceIndex, *source);
   2365   store->set(JSRegExp::kFlagsIndex, Smi::FromInt(flags.value()));
   2366   store->set(JSRegExp::kIrregexpLatin1CodeIndex, uninitialized);
   2367   store->set(JSRegExp::kIrregexpUC16CodeIndex, uninitialized);
   2368   store->set(JSRegExp::kIrregexpLatin1CodeSavedIndex, uninitialized);
   2369   store->set(JSRegExp::kIrregexpUC16CodeSavedIndex, uninitialized);
   2370   store->set(JSRegExp::kIrregexpMaxRegisterCountIndex, Smi::FromInt(0));
   2371   store->set(JSRegExp::kIrregexpCaptureCountIndex,
   2372              Smi::FromInt(capture_count));
   2373   regexp->set_data(*store);
   2374 }
   2375 
   2376 
   2377 
   2378 MaybeHandle<FunctionTemplateInfo> Factory::ConfigureInstance(
   2379     Handle<FunctionTemplateInfo> desc, Handle<JSObject> instance) {
   2380   // Configure the instance by adding the properties specified by the
   2381   // instance template.
   2382   Handle<Object> instance_template(desc->instance_template(), isolate());
   2383   if (!instance_template->IsUndefined()) {
   2384       RETURN_ON_EXCEPTION(
   2385           isolate(),
   2386           Execution::ConfigureInstance(isolate(), instance, instance_template),
   2387           FunctionTemplateInfo);
   2388   }
   2389   return desc;
   2390 }
   2391 
   2392 
   2393 Handle<Object> Factory::GlobalConstantFor(Handle<String> name) {
   2394   if (String::Equals(name, undefined_string())) return undefined_value();
   2395   if (String::Equals(name, nan_string())) return nan_value();
   2396   if (String::Equals(name, infinity_string())) return infinity_value();
   2397   return Handle<Object>::null();
   2398 }
   2399 
   2400 
   2401 Handle<Object> Factory::ToBoolean(bool value) {
   2402   return value ? true_value() : false_value();
   2403 }
   2404 
   2405 
   2406 } }  // namespace v8::internal
   2407