Changeset 36778 in webkit for trunk/JavaScriptCore/kjs/JSArray.cpp

Timestamp:

Sep 22, 2008, 2:04:45 PM (17 years ago)

Author:

Darin Adler

Message:

2008-09-22 Darin Adler <Darin Adler>

Reviewed by Sam Weinig.

• ​https://bugs.webkit.org/show_bug.cgi?id=20993 Array.push/pop need optimized cases for JSArray

3% or so speedup on DeltaBlue benchmark.

• kjs/ArrayPrototype.cpp: (JSC::arrayProtoFuncPop): Call JSArray::pop when appropriate. (JSC::arrayProtoFuncPush): Call JSArray::push when appropriate.

• kjs/JSArray.cpp: (JSC::JSArray::putSlowCase): Set m_fastAccessCutoff when appropriate, getting us into the fast code path. (JSC::JSArray::pop): Added. (JSC::JSArray::push): Added.
• kjs/JSArray.h: Added push and pop.

• kjs/operations.cpp: (JSC::throwOutOfMemoryError): Don't inline this. Helps us avoid PIC branches.

File:

• trunk/JavaScriptCore/kjs/JSArray.cpp (modified) (2 diffs)

trunk/JavaScriptCore/kjs/JSArray.cpp

@@ -312 +312 @@
         if (increaseVectorLength(i + 1)) {
             storage = m_storage;
-            ++storage->m_numValuesInVector;
             storage->m_vector[i] = value;
+            if (++storage->m_numValuesInVector == storage->m_length)
+                m_fastAccessCutoff = storage->m_length;
             checkConsistency();
         } else
@@ -509 +510 @@
 }
 
+JSValue* JSArray::pop()
+{
+    checkConsistency();
+
+    unsigned length = m_storage->m_length;
+    if (!length)
+        return jsUndefined();
+
+    --length;
+
+    JSValue* result;
+
+    if (m_fastAccessCutoff > length) {
+        JSValue*& valueSlot = m_storage->m_vector[length];
+        result = valueSlot;
+        ASSERT(result);
+        valueSlot = 0;
+        --m_storage->m_numValuesInVector;
+        m_fastAccessCutoff = length;
+    } else if (length < m_storage->m_vectorLength) {
+        JSValue*& valueSlot = m_storage->m_vector[length];
+        result = valueSlot;
+        valueSlot = 0;
+        if (result)
+            --m_storage->m_numValuesInVector;
+        else
+            result = jsUndefined();
+    } else {
+        result = jsUndefined();
+        if (SparseArrayValueMap* map = m_storage->m_sparseValueMap) {
+            SparseArrayValueMap::iterator it = map->find(length);
+            if (it != map->end()) {
+                result = it->second;
+                map->remove(it);
+                if (map->isEmpty()) {
+                    delete map;
+                    m_storage->m_sparseValueMap = 0;
+                }
+            }
+        }
+    }
+
+    m_storage->m_length = length;
+
+    checkConsistency();
+
+    return result;
+}
+
+void JSArray::push(ExecState* exec, JSValue* value)
+{
+    checkConsistency();
+
+    if (m_storage->m_length < m_storage->m_vectorLength) {
+        ASSERT(!m_storage->m_vector[m_storage->m_length]);
+        m_storage->m_vector[m_storage->m_length] = value;
+        if (++m_storage->m_numValuesInVector == ++m_storage->m_length)
+            m_fastAccessCutoff = m_storage->m_length;
+        checkConsistency();
+        return;
+    }
+
+    if (m_storage->m_length < MIN_SPARSE_ARRAY_INDEX) {
+        SparseArrayValueMap* map = m_storage->m_sparseValueMap;
+        if (!map || map->isEmpty()) {
+            if (increaseVectorLength(m_storage->m_length + 1)) {
+                m_storage->m_vector[m_storage->m_length] = value;
+                if (++m_storage->m_numValuesInVector == ++m_storage->m_length)
+                    m_fastAccessCutoff = m_storage->m_length;
+                checkConsistency();
+                return;
+            }
+            checkConsistency();
+            throwOutOfMemoryError(exec);
+            return;
+        }
+    }
+
+    putSlowCase(exec, m_storage->m_length++, value);
+}
+
 void JSArray::mark()
 {