Revision: 14191
Author: [email protected]
Date: Tue Apr 9 09:49:28 2013
Log: Eagerly parse expected transitions in JSON.
Review URL: https://chromiumcodereview.appspot.com/13741010
http://code.google.com/p/v8/source/detail?r=14191
Modified:
/branches/bleeding_edge/src/json-parser.h
/branches/bleeding_edge/src/objects-inl.h
/branches/bleeding_edge/src/objects.cc
/branches/bleeding_edge/src/objects.h
=======================================
--- /branches/bleeding_edge/src/json-parser.h Thu Mar 28 04:19:38 2013
+++ /branches/bleeding_edge/src/json-parser.h Tue Apr 9 09:49:28 2013
@@ -102,9 +102,37 @@
Handle<String> ParseJsonString() {
return ScanJsonString<false>();
}
+
+ bool ParseJsonString(Handle<String> expected) {
+ int length = expected->length();
+ if (source_->length() - position_ - 1 > length) {
+ AssertNoAllocation no_gc;
+ String::FlatContent content = expected->GetFlatContent();
+ if (content.IsAscii()) {
+ ASSERT_EQ('"', c0_);
+ const uint8_t* input_chars = seq_source_->GetChars() + position_ +
1;
+ const uint8_t* expected_chars = content.ToOneByteVector().start();
+ for (int i = 0; i < length; i++) {
+ uint8_t c0 = input_chars[i];
+ if (c0 != expected_chars[i] ||
+ c0 == '"' || c0 < 0x20 || c0 == '\\') {
+ return false;
+ }
+ }
+ if (input_chars[length] == '"') {
+ position_ = position_ + length + 1;
+ AdvanceSkipWhitespace();
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
Handle<String> ParseJsonInternalizedString() {
return ScanJsonString<true>();
}
+
template <bool is_internalized>
Handle<String> ScanJsonString();
// Creates a new string and copies prefix[start..end] into the beginning
@@ -294,8 +322,13 @@
HandleScope scope(isolate());
Handle<JSObject> json_object =
factory()->NewJSObject(object_constructor(), pretenure_);
+ Handle<Map> map(json_object->map());
+ ZoneScope zone_scope(zone(), DELETE_ON_EXIT);
+ ZoneList<Handle<Object> > properties(8, zone());
ASSERT_EQ(c0_, '{');
+ bool transitioning = true;
+
AdvanceSkipWhitespace();
if (c0_ != '}') {
do {
@@ -339,24 +372,75 @@
c0_ = '"';
#endif
- Handle<String> key = ParseJsonInternalizedString();
- if (key.is_null() || c0_ != ':') return ReportUnexpectedCharacter();
+ Handle<String> key;
+ Handle<Object> value;
- AdvanceSkipWhitespace();
- Handle<Object> value = ParseJsonValue();
- if (value.is_null()) return ReportUnexpectedCharacter();
+ // Try to follow existing transitions as long as possible. Once we
stop
+ // transitioning, no transition can be found anymore.
+ if (transitioning) {
+ // First check whether there is a single expected transition. If
so, try
+ // to parse it first.
+ bool follow_expected = false;
+ if (seq_ascii) {
+ key = JSObject::ExpectedTransitionKey(map);
+ follow_expected = !key.is_null() && ParseJsonString(key);
+ }
+ // If the expected transition hits, follow it.
+ if (follow_expected) {
+ map = JSObject::ExpectedTransitionTarget(map);
+ } else {
+ // If the expected transition failed, parse an internalized
string and
+ // try to find a matching transition.
+ key = ParseJsonInternalizedString();
+ if (key.is_null()) return ReportUnexpectedCharacter();
- if (JSObject::TryTransitionToField(json_object, key)) {
- int index = json_object->LastAddedFieldIndex();
- json_object->FastPropertyAtPut(index, *value);
+ Handle<Map> target = JSObject::FindTransitionToField(map, key);
+ // If a transition was found, follow it and continue.
+ if (!target.is_null()) {
+ map = target;
+ } else {
+ // If no transition was found, commit the intermediate state
to the
+ // object and stop transitioning.
+ JSObject::TransitionToMap(json_object, map);
+ int length = properties.length();
+ for (int i = 0; i < length; i++) {
+ json_object->FastPropertyAtPut(i, *properties[i]);
+ }
+ transitioning = false;
+ }
+ }
+ if (c0_ != ':') return ReportUnexpectedCharacter();
+
+ AdvanceSkipWhitespace();
+ value = ParseJsonValue();
+ if (value.is_null()) return ReportUnexpectedCharacter();
+
+ properties.Add(value, zone());
+ if (transitioning) continue;
} else {
- JSObject::SetLocalPropertyIgnoreAttributes(
- json_object, key, value, NONE);
+ key = ParseJsonInternalizedString();
+ if (key.is_null() || c0_ != ':') return
ReportUnexpectedCharacter();
+
+ AdvanceSkipWhitespace();
+ value = ParseJsonValue();
+ if (value.is_null()) return ReportUnexpectedCharacter();
}
+
+ JSObject::SetLocalPropertyIgnoreAttributes(
+ json_object, key, value, NONE);
} while (MatchSkipWhiteSpace(','));
if (c0_ != '}') {
return ReportUnexpectedCharacter();
}
+
+ // If we transitioned until the very end, transition the map now.
+ if (transitioning) {
+ JSObject::TransitionToMap(json_object, map);
+ int length = properties.length();
+ for (int i = 0; i < length; i++) {
+ json_object->FastPropertyAtPut(i, *properties[i]);
+ }
+ }
}
AdvanceSkipWhitespace();
return scope.CloseAndEscape(json_object);
@@ -644,22 +728,32 @@
uint32_t capacity = string_table->Capacity();
uint32_t entry = StringTable::FirstProbe(hash, capacity);
uint32_t count = 1;
+ Handle<String> result;
while (true) {
Object* element = string_table->KeyAt(entry);
if (element == isolate()->heap()->undefined_value()) {
// Lookup failure.
+ result = factory()->InternalizeOneByteString(
+ seq_source_, position_, length);
break;
}
if (element != isolate()->heap()->the_hole_value() &&
String::cast(element)->IsOneByteEqualTo(string_vector)) {
- // Lookup success, update the current position.
- position_ = position;
- // Advance past the last '"'.
- AdvanceSkipWhitespace();
- return Handle<String>(String::cast(element), isolate());
+ result = Handle<String>(String::cast(element), isolate());
+#ifdef DEBUG
+ uint32_t hash_field =
+ (hash << String::kHashShift) | String::kIsNotArrayIndexMask;
+ ASSERT_EQ(static_cast<int>(result->Hash()),
+ static_cast<int>(hash_field >> String::kHashShift));
+#endif
+ break;
}
entry = StringTable::NextProbe(entry, count++, capacity);
}
+ position_ = position;
+ // Advance past the last '"'.
+ AdvanceSkipWhitespace();
+ return result;
}
int beg_pos = position_;
@@ -682,14 +776,10 @@
}
} while (c0_ != '"');
int length = position_ - beg_pos;
- Handle<String> result;
- if (seq_ascii && is_internalized) {
- result = factory()->InternalizeOneByteString(seq_source_, beg_pos,
length);
- } else {
- result = factory()->NewRawOneByteString(length, pretenure_);
- uint8_t* dest = SeqOneByteString::cast(*result)->GetChars();
- String::WriteToFlat(*source_, dest, beg_pos, position_);
- }
+ Handle<String> result = factory()->NewRawOneByteString(length,
pretenure_);
+ uint8_t* dest = SeqOneByteString::cast(*result)->GetChars();
+ String::WriteToFlat(*source_, dest, beg_pos, position_);
+
ASSERT_EQ('"', c0_);
// Advance past the last '"'.
AdvanceSkipWhitespace();
=======================================
--- /branches/bleeding_edge/src/objects-inl.h Wed Apr 3 10:06:22 2013
+++ /branches/bleeding_edge/src/objects-inl.h Tue Apr 9 09:49:28 2013
@@ -1488,22 +1488,59 @@
}
-bool JSObject::TryTransitionToField(Handle<JSObject> object,
- Handle<Name> key) {
- if (!object->map()->HasTransitionArray()) return false;
- Handle<Map> target;
- {
- AssertNoAllocation no_allocation;
- TransitionArray* transitions = object->map()->transitions();
- int transition = transitions->Search(*key);
- if (transition == TransitionArray::kNotFound) return false;
- PropertyDetails target_details =
transitions->GetTargetDetails(transition);
- if (target_details.type() != FIELD) return false;
- if (target_details.attributes() != NONE) return false;
- target = Handle<Map>(transitions->GetTarget(transition));
+MaybeObject* JSObject::TransitionToMap(Map* map) {
+ ASSERT(this->map()->inobject_properties() == map->inobject_properties());
+ ElementsKind expected_kind = this->map()->elements_kind();
+ if (map->elements_kind() != expected_kind) {
+ MaybeObject* maybe_map = map->AsElementsKind(expected_kind);
+ if (!maybe_map->To(&map)) return maybe_map;
}
- JSObject::AddFastPropertyUsingMap(object, target);
- return true;
+ int total_size =
+ map->NumberOfOwnDescriptors() + map->unused_property_fields();
+ int out_of_object = total_size - map->inobject_properties();
+ if (out_of_object != properties()->length()) {
+ FixedArray* new_properties;
+ MaybeObject* maybe_properties = properties()->CopySize(out_of_object);
+ if (!maybe_properties->To(&new_properties)) return maybe_properties;
+ set_properties(new_properties);
+ }
+ set_map(map);
+ return this;
+}
+
+
+Handle<String> JSObject::ExpectedTransitionKey(Handle<Map> map) {
+ AssertNoAllocation no_gc;
+ if (!map->HasTransitionArray()) return Handle<String>::null();
+ TransitionArray* transitions = map->transitions();
+ if (!transitions->IsSimpleTransition()) return Handle<String>::null();
+ int transition = TransitionArray::kSimpleTransitionIndex;
+ PropertyDetails details = transitions->GetTargetDetails(transition);
+ Name* name = transitions->GetKey(transition);
+ if (details.type() != FIELD) return Handle<String>::null();
+ if (details.attributes() != NONE) return Handle<String>::null();
+ if (!name->IsString()) return Handle<String>::null();
+ return Handle<String>(String::cast(name));
+}
+
+
+Handle<Map> JSObject::ExpectedTransitionTarget(Handle<Map> map) {
+ ASSERT(!ExpectedTransitionKey(map).is_null());
+ return Handle<Map>(map->transitions()->GetTarget(
+ TransitionArray::kSimpleTransitionIndex));
+}
+
+
+Handle<Map> JSObject::FindTransitionToField(Handle<Map> map, Handle<Name>
key) {
+ AssertNoAllocation no_allocation;
+ if (!map->HasTransitionArray()) return Handle<Map>::null();
+ TransitionArray* transitions = map->transitions();
+ int transition = transitions->Search(*key);
+ if (transition == TransitionArray::kNotFound) return Handle<Map>::null();
+ PropertyDetails target_details =
transitions->GetTargetDetails(transition);
+ if (target_details.type() != FIELD) return Handle<Map>::null();
+ if (target_details.attributes() != NONE) return Handle<Map>::null();
+ return Handle<Map>(transitions->GetTarget(transition));
}
=======================================
--- /branches/bleeding_edge/src/objects.cc Thu Apr 4 12:12:59 2013
+++ /branches/bleeding_edge/src/objects.cc Tue Apr 9 09:49:28 2013
@@ -2602,13 +2602,18 @@
return start_map->CopyAsElementsKind(to_kind, OMIT_TRANSITION);
}
- Map* closest_map = FindClosestElementsTransition(start_map, to_kind);
+ return start_map->AsElementsKind(to_kind);
+}
- if (closest_map->elements_kind() == to_kind) {
+
+MaybeObject* Map::AsElementsKind(ElementsKind kind) {
+ Map* closest_map = FindClosestElementsTransition(this, kind);
+
+ if (closest_map->elements_kind() == kind) {
return closest_map;
}
- return AddMissingElementsTransitions(closest_map, to_kind);
+ return AddMissingElementsTransitions(closest_map, kind);
}
@@ -3071,6 +3076,13 @@
object->GetIsolate(),
object->AddFastPropertyUsingMap(*map));
}
+
+
+void JSObject::TransitionToMap(Handle<JSObject> object, Handle<Map> map) {
+ CALL_HEAP_FUNCTION_VOID(
+ object->GetIsolate(),
+ object->TransitionToMap(*map));
+}
MaybeObject* JSObject::SetPropertyForResult(LookupResult* lookup,
=======================================
--- /branches/bleeding_edge/src/objects.h Tue Apr 9 01:42:57 2013
+++ /branches/bleeding_edge/src/objects.h Tue Apr 9 09:49:28 2013
@@ -1770,10 +1770,13 @@
Handle<Object> value,
PropertyAttributes attributes);
+ static inline Handle<String> ExpectedTransitionKey(Handle<Map> map);
+ static inline Handle<Map> ExpectedTransitionTarget(Handle<Map> map);
+
// Try to follow an existing transition to a field with attributes NONE.
The
// return value indicates whether the transition was successful.
- static inline bool TryTransitionToField(Handle<JSObject> object,
- Handle<Name> key);
+ static inline Handle<Map> FindTransitionToField(Handle<Map> map,
+ Handle<Name> key);
inline int LastAddedFieldIndex();
@@ -1781,6 +1784,8 @@
// passed map. This also extends the property backing store if necessary.
static void AddFastPropertyUsingMap(Handle<JSObject> object, Handle<Map>
map);
inline MUST_USE_RESULT MaybeObject* AddFastPropertyUsingMap(Map* map);
+ static void TransitionToMap(Handle<JSObject> object, Handle<Map> map);
+ inline MUST_USE_RESULT MaybeObject* TransitionToMap(Map* map);
// Can cause GC.
MUST_USE_RESULT MaybeObject* SetLocalPropertyIgnoreAttributes(
@@ -5244,6 +5249,7 @@
Descriptor* descriptor,
int index,
TransitionFlag flag);
+ MUST_USE_RESULT MaybeObject* AsElementsKind(ElementsKind kind);
MUST_USE_RESULT MaybeObject* CopyAsElementsKind(ElementsKind kind,
TransitionFlag flag);
--
--
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