2009-04-16 Stephanie Lewis <slewis@apple.com>

        Reviewed by Oliver Hunt.

        <rdar://problem/6744652> 32-bit to 64-bit: Javascript hash tables double in size

        Remove perfect hash optimization which removes 1 MB of overhead on 32-bit and almost 2 MB on 64-bit.  Removing the optimization was not a regression on SunSpider and the acid 3 test still passes.

        * create_hash_table:
        * runtime/Lookup.cpp:
        (JSC::HashTable::createTable):
        (JSC::HashTable::deleteTable):
        * runtime/Lookup.h:
        (JSC::HashEntry::initialize):
        (JSC::HashEntry::next):
        (JSC::HashTable::entry):
        * runtime/Structure.cpp:
        (JSC::Structure::getEnumerableNamesFromClassInfoTable):



git-svn-id: svn://svn.chromium.org/blink/trunk@42606 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/JavaScriptCore/ChangeLog

+2009-04-16  Stephanie Lewis  <slewis@apple.com>
+
+        Reviewed by Oliver Hunt.
+
+        <rdar://problem/6744652> 32-bit to 64-bit: Javascript hash tables double in size
+
+        Remove perfect hash optimization which removes 1 MB of overhead on 32-bit and almost 2 MB on 64-bit.  Removing the optimization was not a regression on SunSpider and the acid 3 test still passes.
+
+        * create_hash_table:
+        * runtime/Lookup.cpp:
+        (JSC::HashTable::createTable):
+        (JSC::HashTable::deleteTable):
+        * runtime/Lookup.h:
+        (JSC::HashEntry::initialize):
+        (JSC::HashEntry::next):
+        (JSC::HashTable::entry):
+        * runtime/Structure.cpp:
+        (JSC::Structure::getEnumerableNamesFromClassInfoTable):
+
 2009-04-16  Oliver Hunt  <oliver@apple.com>
 
         Reviewed by Gavin Barraclough.

third_party/WebKit/JavaScriptCore/create_hash_table

@@ -269,10 +269,6 @@ sub output() {
     print "   { 0, 0, 0, 0 }\n";
     print "};\n\n";
     print "extern const struct HashTable $name =\n";
-    print "#if ENABLE(PERFECT_HASH_SIZE)\n";
-    print "    \{ ", $pefectHashSize - 1, ", $nameEntries, 0 \};\n";
-    print "#else\n";
     print "    \{ $compactSize, $compactHashSizeMask, $nameEntries, 0 \};\n";
-    print "#endif\n\n";
     print "} // namespace\n";
 }

third_party/WebKit/JavaScriptCore/runtime/Lookup.cpp

@@ -26,19 +26,6 @@ namespace JSC {
 
 void HashTable::createTable(JSGlobalData* globalData) const
 {
-#if ENABLE(PERFECT_HASH_SIZE)
-    ASSERT(!table);
-    HashEntry* entries = new HashEntry[hashSizeMask + 1];
-    for (int i = 0; i <= hashSizeMask; ++i)
-        entries[i].setKey(0);
-    for (int i = 0; values[i].key; ++i) {
-        UString::Rep* identifier = Identifier::add(globalData, values[i].key).releaseRef();
-        int hashIndex = identifier->computedHash() & hashSizeMask;
-        ASSERT(!entries[hashIndex].key());
-        entries[hashIndex].initialize(identifier, values[i].attributes, values[i].value1, values[i].value2);
-    }
-    table = entries;
-#else
     ASSERT(!table);
     int linkIndex = compactHashSizeMask + 1;
     HashEntry* entries = new HashEntry[compactSize];
@@ -61,17 +48,12 @@ void HashTable::createTable(JSGlobalData* globalData) const
         entry->initialize(identifier, values[i].attributes, values[i].value1, values[i].value2);
     }
     table = entries;
-#endif
 }
 
 void HashTable::deleteTable() const
 {
     if (table) {
-#if ENABLE(PERFECT_HASH_SIZE)
-        int max = hashSizeMask + 1;
-#else
         int max = compactSize;
-#endif
         for (int i = 0; i != max; ++i) {
             if (UString::Rep* key = table[i].key())
                 key->deref();

third_party/WebKit/JavaScriptCore/runtime/Lookup.h

@@ -30,10 +30,6 @@
 #include <stdio.h>
 #include <wtf/Assertions.h>
 
-// Set ENABLE_PERFECT_HASH_SIZE to 0 to save memory at the
-// cost of speed.  Test your platform as results may vary.
-#define ENABLE_PERFECT_HASH_SIZE 1
-
 namespace JSC {
 
     // Hash table generated by the create_hash_table script.
@@ -57,9 +53,7 @@ namespace JSC {
             m_attributes = attributes;
             m_u.store.value1 = v1;
             m_u.store.value2 = v2;
-#if !ENABLE(PERFECT_HASH_SIZE)
             m_next = 0;
-#endif
         }
 
         void setKey(UString::Rep* key) { m_key = key; }
@@ -75,10 +69,8 @@ namespace JSC {
 
         intptr_t lexerValue() const { ASSERT(!m_attributes); return m_u.lexer.value; }
 
-#if !ENABLE(PERFECT_HASH_SIZE)
         void setNext(HashEntry *next) { m_next = next; }
         HashEntry* next() const { return m_next; }
-#endif
 
     private:
         UString::Rep* m_key;
@@ -103,18 +95,14 @@ namespace JSC {
             } lexer;
         } m_u;
 
-#if !ENABLE(PERFECT_HASH_SIZE)
         HashEntry* m_next;
-#endif
     };
 
     struct HashTable {
-#if ENABLE(PERFECT_HASH_SIZE)
-        int hashSizeMask; // Precomputed size for the hash table (minus 1).
-#else
+
         int compactSize;
         int compactHashSizeMask;
-#endif
+
         const HashTableValue* values; // Fixed values generated by script.
         mutable const HashEntry* table; // Table allocated at runtime.
 
@@ -148,13 +136,6 @@ namespace JSC {
     private:
         ALWAYS_INLINE const HashEntry* entry(const Identifier& identifier) const
         {
-#if ENABLE(PERFECT_HASH_SIZE)
-            ASSERT(table);
-            const HashEntry* entry = &table[identifier.ustring().rep()->computedHash() & hashSizeMask];
-            if (entry->key() != identifier.ustring().rep())
-                return 0;
-            return entry;
-#else
             ASSERT(table);
 
             const HashEntry* entry = &table[identifier.ustring().rep()->computedHash() & compactHashSizeMask];
@@ -169,7 +150,6 @@ namespace JSC {
             } while (entry);
 
             return 0;
-#endif
         }
 
         // Convert the hash table keys to identifiers.

third_party/WebKit/JavaScriptCore/runtime/Structure.cpp

@@ -948,11 +948,8 @@ void Structure::getEnumerableNamesFromClassInfoTable(ExecState* exec, const Clas
             continue;
         table->initializeIfNeeded(exec);
         ASSERT(table->table);
-#if ENABLE(PERFECT_HASH_SIZE)
-        int hashSizeMask = table->hashSizeMask;
-#else
+
         int hashSizeMask = table->compactSize - 1;
-#endif
         const HashEntry* entry = table->table;
         for (int i = 0; i <= hashSizeMask; ++i, ++entry) {
             if (entry->key() && !(entry->attributes() & DontEnum))