Title: [87838] trunk/Source/_javascript_Core
- Revision
- 87838
- Author
- [email protected]
- Date
- 2011-06-01 13:09:04 -0700 (Wed, 01 Jun 2011)
Log Message
2011-06-01 Oliver Hunt <[email protected]>
Reviewed by Geoffrey Garen.
Add single character lookup cache to IdentifierArena
https://bugs.webkit.org/show_bug.cgi?id=61879
Add a simple lookup cache for single ascii character
identifiers. Produces around a 2% improvement in parse
time for my adhoc parser test.
* parser/ParserArena.h:
(JSC::IdentifierArena::IdentifierArena):
(JSC::IdentifierArena::clear):
(JSC::IdentifierArena::makeIdentifier):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (87837 => 87838)
--- trunk/Source/_javascript_Core/ChangeLog 2011-06-01 19:52:13 UTC (rev 87837)
+++ trunk/Source/_javascript_Core/ChangeLog 2011-06-01 20:09:04 UTC (rev 87838)
@@ -1,3 +1,19 @@
+2011-06-01 Oliver Hunt <[email protected]>
+
+ Reviewed by Geoffrey Garen.
+
+ Add single character lookup cache to IdentifierArena
+ https://bugs.webkit.org/show_bug.cgi?id=61879
+
+ Add a simple lookup cache for single ascii character
+ identifiers. Produces around a 2% improvement in parse
+ time for my adhoc parser test.
+
+ * parser/ParserArena.h:
+ (JSC::IdentifierArena::IdentifierArena):
+ (JSC::IdentifierArena::clear):
+ (JSC::IdentifierArena::makeIdentifier):
+
2011-05-31 Oliver Hunt <[email protected]>
Reviewed by Geoffrey Garen.
Modified: trunk/Source/_javascript_Core/parser/ParserArena.h (87837 => 87838)
--- trunk/Source/_javascript_Core/parser/ParserArena.h 2011-06-01 19:52:13 UTC (rev 87837)
+++ trunk/Source/_javascript_Core/parser/ParserArena.h 2011-06-01 20:09:04 UTC (rev 87838)
@@ -37,19 +37,38 @@
class IdentifierArena {
WTF_MAKE_FAST_ALLOCATED;
public:
+ IdentifierArena()
+ {
+ clear();
+ }
+
ALWAYS_INLINE const Identifier& makeIdentifier(JSGlobalData*, const UChar* characters, size_t length);
const Identifier& makeNumericIdentifier(JSGlobalData*, double number);
- void clear() { m_identifiers.clear(); }
+ void clear()
+ {
+ m_identifiers.clear();
+ for (unsigned i = 0; i < 128; i++)
+ m_shortIdentifiers[i] = 0;
+ }
bool isEmpty() const { return m_identifiers.isEmpty(); }
private:
+ static const int MaximumCachableCharacter = 128;
typedef SegmentedVector<Identifier, 64> IdentifierVector;
IdentifierVector m_identifiers;
+ FixedArray<Identifier*, MaximumCachableCharacter> m_shortIdentifiers;
};
ALWAYS_INLINE const Identifier& IdentifierArena::makeIdentifier(JSGlobalData* globalData, const UChar* characters, size_t length)
{
+ if (length == 1 && characters[0] < MaximumCachableCharacter) {
+ if (Identifier* ident = m_shortIdentifiers[characters[0]])
+ return *ident;
+ m_identifiers.append(Identifier(globalData, characters, length));
+ m_shortIdentifiers[characters[0]] = &m_identifiers.last();
+ return m_identifiers.last();
+ }
m_identifiers.append(Identifier(globalData, characters, length));
return m_identifiers.last();
}
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