Changeset 47622 in webkit for trunk/JavaScriptCore/runtime/NumericStrings.h

Timestamp:

Aug 20, 2009, 10:41:54 PM (16 years ago)

Author:

[email protected]

Message:

Added a number => string cache.

Patch by Geoffrey Garen <​[email protected]> on 2009-08-20
Reviewed by Maciej Stachowiak.

1.07x faster on v8 (1.7x faster on v8-splay).
1.004x faster on SunSpider.

• runtime/JSCell.h: Moved JSValue::toString to JSString.h.
• runtime/JSGlobalData.h: Holds the cache.
• runtime/JSNumberCell.cpp:

(JSC::JSNumberCell::toString):
(JSC::JSNumberCell::toThisString): Removed -0 special case.
UString handles this now, since too many clients were
special-casing it.

• runtime/JSString.h:

(JSC::JSValue::toString): Use the cache when converting
an int or double to string.

• runtime/Operations.h:

(JSC::concatenateStrings): Call toString to take advantage
of the cache.

• runtime/SmallStrings.h:

(JSC::NumericStrings::add):
(JSC::NumericStrings::lookup): The cache.

• runtime/UString.cpp:

(JSC::UString::from): Added -0 special case mentioned above.
Removed appendNumeric because it's mutually exclusive with the
cache.

File:

• trunk/JavaScriptCore/runtime/NumericStrings.h (copied) (copied from trunk/JavaScriptCore/runtime/SmallStrings.h ) (2 diffs)

trunk/JavaScriptCore/runtime/NumericStrings.h

@@ -1 +1 @@
 /*
- * Copyright (C) 2008 Apple Inc. All Rights Reserved.
+ * Copyright (C) 2009 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -24 +24 @@
  */
 
-#ifndef SmallStrings_h
-#define SmallStrings_h
+#ifndef NumericStrings_h
+#define NumericStrings_h
 
 #include "UString.h"
-#include <wtf/OwnPtr.h>
+#include <wtf/HashFunctions.h>
 
 namespace JSC {
 
-    class JSGlobalData;
-    class JSString;
-
-    class SmallStringsStorage;
-
-    class SmallStrings : public Noncopyable {
+    class NumericStrings {
     public:
-        SmallStrings();
-        ~SmallStrings();
-
-        JSString* emptyString(JSGlobalData* globalData)
+        UString add(double d)
         {
-            if (!m_emptyString)
-                createEmptyString(globalData);
-            return m_emptyString;
-        }
-        JSString* singleCharacterString(JSGlobalData* globalData, unsigned char character)
-        {
-            if (!m_singleCharacterStrings[character])
-                createSingleCharacterString(globalData, character);
-            return m_singleCharacterStrings[character];
+            CacheEntry<double>& entry = lookup(d);
+            if (d == entry.key && !entry.value.isNull())
+                return entry.value;
+            entry.key = d;
+            entry.value = UString::from(d);
+            return entry.value;
         }
 
-        UString::Rep* singleCharacterStringRep(unsigned char character);
-
-        void mark();
-
-        unsigned count() const;
+        UString add(int i)
+        {
+            CacheEntry<int>& entry = lookup(i);
+            if (i == entry.key && !entry.value.isNull())
+                return entry.value;
+            entry.key = i;
+            entry.value = UString::from(i);
+            return entry.value;
+        }
 
     private:
-        void createEmptyString(JSGlobalData*);
-        void createSingleCharacterString(JSGlobalData*, unsigned char);
+        static const size_t cacheSize = 64;
 
-        JSString* m_emptyString;
-        JSString* m_singleCharacterStrings[0x100];
-        OwnPtr<SmallStringsStorage> m_storage;
+        template<typename T>
+        struct CacheEntry {
+            T key;
+            UString value;
+        };
+
+        CacheEntry<double>& lookup(double d) { return doubleCache[WTF::FloatHash<double>::hash(d) & (cacheSize - 1)]; }
+        CacheEntry<int>& lookup(int i) { return intCache[WTF::IntHash<int>::hash(i) & (cacheSize - 1)]; }
+
+        CacheEntry<double> doubleCache[cacheSize];
+        CacheEntry<int> intCache[cacheSize];
     };
 
 } // namespace JSC
 
-#endif // SmallStrings_h
+#endif // NumericStrings_h