[SCM] WebKit Debian packaging branch, debian/experimental, updated. upstream/1.3.3-9427-gc2be6fc

[commit-queue at webkit.org]

The following commit has been merged in the debian/experimental branch:
commit 70a90fc6f2d66bb4a95496e4611af7ec91959bd0
Author: commit-queue at webkit.org <commit-queue at webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Date:   Wed Aug 11 12:14:06 2010 +0000

    2010-08-11  Nathan Lawrence  <nlawrence at apple.com>
    
            Reviewed by Geoffrey Garen.
    
            At collection time, we frequently want to mark a cell, while checking
            whether it was originally checked.  Previously, this was a get
            operation follwed by a set operation.  Fusing the two saves
            computation and gives a 0.5% sunspider speedup.
    
            * runtime/Collector.h:
            (JSC::CollectorBitmap::getset):
            (JSC::Heap::checkMarkCell):
            * runtime/JSArray.h:
            (JSC::MarkStack::drain):
            * runtime/JSCell.h:
            (JSC::MarkStack::append):
    
    git-svn-id: http://svn.webkit.org/repository/webkit/trunk@65146 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/JavaScriptCore/ChangeLog b/JavaScriptCore/ChangeLog
index fccb23b..6160b31 100644
--- a/JavaScriptCore/ChangeLog
+++ b/JavaScriptCore/ChangeLog
@@ -1,3 +1,20 @@
+2010-08-11  Nathan Lawrence  <nlawrence at apple.com>
+
+        Reviewed by Geoffrey Garen.
+
+        At collection time, we frequently want to mark a cell, while checking
+        whether it was originally checked.  Previously, this was a get
+        operation follwed by a set operation.  Fusing the two saves
+        computation and gives a 0.5% sunspider speedup.
+
+        * runtime/Collector.h:
+        (JSC::CollectorBitmap::getset):
+        (JSC::Heap::checkMarkCell):
+        * runtime/JSArray.h:
+        (JSC::MarkStack::drain):
+        * runtime/JSCell.h:
+        (JSC::MarkStack::append):
+
 2010-08-11  Steve Falkenburg  <sfalken at apple.com>
 
         Reviewed by Adam Roben.
diff --git a/JavaScriptCore/runtime/Collector.h b/JavaScriptCore/runtime/Collector.h
index 38c178b..05d5c10 100644
--- a/JavaScriptCore/runtime/Collector.h
+++ b/JavaScriptCore/runtime/Collector.h
@@ -130,6 +130,7 @@ namespace JSC {
         void registerThread(); // Only needs to be called by clients that can use the same heap from multiple threads.
 
         static bool isCellMarked(const JSCell*);
+        static bool checkMarkCell(const JSCell*);
         static void markCell(JSCell*);
 
         WeakGCHandle* addWeakGCHandle(JSCell*);
@@ -226,6 +227,14 @@ namespace JSC {
         FixedArray<uint32_t, BITMAP_WORDS> bits;
         bool get(size_t n) const { return !!(bits[n >> 5] & (1 << (n & 0x1F))); } 
         void set(size_t n) { bits[n >> 5] |= (1 << (n & 0x1F)); } 
+        bool getset(size_t n)
+        {
+            unsigned i = (1 << (n & 0x1F));
+            uint32_t& b = bits[n >> 5];
+            bool r = !!(b & i);
+            b |= i;
+            return r;
+        } 
         void clear(size_t n) { bits[n >> 5] &= ~(1 << (n & 0x1F)); } 
         void clearAll() { memset(bits.data(), 0, sizeof(bits)); }
         ALWAYS_INLINE void advanceToNextPossibleFreeCell(size_t& startCell)
@@ -288,6 +297,11 @@ namespace JSC {
         return cellBlock(cell)->marked.get(cellOffset(cell));
     }
 
+    inline bool Heap::checkMarkCell(const JSCell* cell)
+    {
+        return cellBlock(cell)->marked.getset(cellOffset(cell));
+    }
+
     inline void Heap::markCell(JSCell* cell)
     {
         cellBlock(cell)->marked.set(cellOffset(cell));
diff --git a/JavaScriptCore/runtime/JSArray.h b/JavaScriptCore/runtime/JSArray.h
index f718d7e..f8a7d81 100644
--- a/JavaScriptCore/runtime/JSArray.h
+++ b/JavaScriptCore/runtime/JSArray.h
@@ -236,7 +236,7 @@ namespace JSC {
                 current.m_values++;
 
                 JSCell* cell;
-                if (!value || !value.isCell() || Heap::isCellMarked(cell = value.asCell())) {
+                if (!value || !value.isCell() || Heap::checkMarkCell(cell = value.asCell())) {
                     if (current.m_values == end) {
                         m_markSets.removeLast();
                         continue;
@@ -244,7 +244,6 @@ namespace JSC {
                     goto findNextUnmarkedNullValue;
                 }
 
-                Heap::markCell(cell);
                 if (cell->structure()->typeInfo().type() < CompoundType) {
                     if (current.m_values == end) {
                         m_markSets.removeLast();
diff --git a/JavaScriptCore/runtime/JSCell.h b/JavaScriptCore/runtime/JSCell.h
index 72f81df..2ffce8d 100644
--- a/JavaScriptCore/runtime/JSCell.h
+++ b/JavaScriptCore/runtime/JSCell.h
@@ -333,9 +333,8 @@ namespace JSC {
     {
         ASSERT(!m_isCheckingForDefaultMarkViolation);
         ASSERT(cell);
-        if (Heap::isCellMarked(cell))
+        if (Heap::checkMarkCell(cell))
             return;
-        Heap::markCell(cell);
         if (cell->structure()->typeInfo().type() >= CompoundType)
             m_values.append(cell);
     }

-- 
WebKit Debian packaging