Ignore:
Timestamp:
Mar 12, 2014, 11:08:35 AM (11 years ago)
Author:
[email protected]
Message:

Reduce memory use for static property maps
​https://bugs.webkit.org/show_bug.cgi?id=129986

Reviewed by Andreas Kling.

Static property tables are currently duplicated on first use from read-only memory into dirty memory
in every process, and since the entries are large (48 bytes) and the tables can be unusually sparse
(we use a custom hash table without a rehash) a lot of memory may be wasted.

Source/JavaScriptCore:

First, reduce the size of the hashtable. Instead of storing values in the table the hashtable maps
from string hashes to indicies into a densely packed array of values. Compute the index table at
compile time as a part of the derived sources step, such that this may be read-only data.

Second, don't copy all data from the HashTableValue array into a HashEntry objects. Instead refer
directly to the HashTableValue entries. The only data that needs to be allocated at runtime are the
keys, which are Identifiers.

  • create_hash_table:
    • emit the hash table index into the derived source (we were calculating this already to ensure chaining does not get too deep).
  • parser/Lexer.cpp:

(JSC::Lexer<LChar>::parseIdentifier):
(JSC::Lexer<UChar>::parseIdentifier):
(JSC::Lexer<T>::parseIdentifierSlowCase):

  • HashEntry -> HashTableValue.
  • parser/Lexer.h:

(JSC::Keywords::getKeyword):

  • HashEntry -> HashTableValue.
  • runtime/ClassInfo.h:
    • removed HashEntry.
  • runtime/JSObject.cpp:

(JSC::getClassPropertyNames):

  • use HashTable::ConstIterator.

(JSC::JSObject::put):
(JSC::JSObject::deleteProperty):
(JSC::JSObject::findPropertyHashEntry):

  • HashEntry -> HashTableValue.

(JSC::JSObject::reifyStaticFunctionsForDelete):

  • changed HashTable::ConstIterator interface.
  • runtime/JSObject.h:
    • HashEntry -> HashTableValue.
  • runtime/Lookup.cpp:

(JSC::HashTable::createTable):

  • table -> keys, keys array is now densely packed.

(JSC::HashTable::deleteTable):

  • table -> keys.

(JSC::setUpStaticFunctionSlot):

  • HashEntry -> HashTableValue.
  • runtime/Lookup.h:

(JSC::HashTableValue::builtinGenerator):
(JSC::HashTableValue::function):
(JSC::HashTableValue::functionLength):
(JSC::HashTableValue::propertyGetter):
(JSC::HashTableValue::propertyPutter):
(JSC::HashTableValue::lexerValue):

  • added accessor methods from HashEntry.

(JSC::HashTable::copy):

  • fields changed.

(JSC::HashTable::initializeIfNeeded):

  • table -> keys.

(JSC::HashTable::entry):

  • HashEntry -> HashTableValue.

(JSC::HashTable::ConstIterator::ConstIterator):

  • iterate packed value array, so no need to skipInvalidKeys().

(JSC::HashTable::ConstIterator::value):
(JSC::HashTable::ConstIterator::key):
(JSC::HashTable::ConstIterator::operator->):

  • accessors now get HashTableValue/StringImpl* separately.

(JSC::HashTable::ConstIterator::operator++):

  • iterate packed value array, so no need to skipInvalidKeys().

(JSC::HashTable::end):

  • end is now size of dense not sparse array.

(JSC::getStaticPropertySlot):
(JSC::getStaticFunctionSlot):
(JSC::getStaticValueSlot):
(JSC::putEntry):
(JSC::lookupPut):

  • HashEntry -> HashTableValue.

Source/WebCore:

  • bindings/js/JSDOMBinding.h:

(WebCore::getStaticValueSlotEntryWithoutCaching):
(WebCore::getStaticValueSlotEntryWithoutCaching<JSDOMWrapper>):

  • HashEntry -> HashTableValue.
  • bindings/js/JSDOMWindowCustom.cpp:

(WebCore::JSDOMWindow::getOwnPropertySlot):

  • HashEntry -> HashTableValue.
  • bindings/js/JSHistoryCustom.cpp:

(WebCore::JSHistory::getOwnPropertySlotDelegate):

  • HashEntry -> HashTableValue.
  • bindings/js/JSLocationCustom.cpp:

(WebCore::JSLocation::getOwnPropertySlotDelegate):
(WebCore::JSLocation::putDelegate):

  • HashEntry -> HashTableValue.
  • bindings/scripts/CodeGeneratorJS.pm:

(GenerateGetOwnPropertySlotBody):

  • HashEntry -> HashTableValue.

(GenerateHashTable):

  • emit the hash table index into the derived source (we were calculating this already to ensure chaining does not get too deep).

LayoutTests:

  • inspector-protocol/debugger/setPauseOnExceptions-all-expected.txt:
  • inspector-protocol/debugger/setPauseOnExceptions-none-expected.txt:
  • inspector-protocol/debugger/setPauseOnExceptions-uncaught-expected.txt:
  • js/dom/dom-static-property-for-in-iteration-expected.txt:
    • Properties now iterated in correct order, not permuted by hash table.
File:
1 edited

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