Changeset 178984 in webkit for trunk/Source/JavaScriptCore/runtime/SmallStrings.h

Timestamp:

Jan 22, 2015, 11:04:05 PM (10 years ago)

Author:

[email protected]

Message:

EdenCollections unnecessarily visit SmallStrings
​https://bugs.webkit.org/show_bug.cgi?id=140762

Reviewed by Geoffrey Garen.

• heap/Heap.cpp:

(JSC::Heap::copyBackingStores): Also added a GCPhase for copying
backing stores, which is a significant portion of garbage collection.
(JSC::Heap::visitSmallStrings): Check to see if we need to visit
SmallStrings based on the collection type.

• runtime/SmallStrings.cpp:

(JSC::SmallStrings::SmallStrings):
(JSC::SmallStrings::visitStrongReferences): Set the fact that we have
visited the SmallStrings since the last modification.

• runtime/SmallStrings.h:

(JSC::SmallStrings::needsToBeVisited): If we're doing a
FullCollection, we need to visit. Otherwise, it depends on whether
we've been visited since the last modification/allocation.

File:

• trunk/Source/JavaScriptCore/runtime/SmallStrings.h (modified) (3 diffs)

trunk/Source/JavaScriptCore/runtime/SmallStrings.h

@@ -89 +89 @@
     JSString* undefinedObjectString() const { return m_undefinedObjectString; }
 
+    bool needsToBeVisited(HeapOperation collectionType) const
+    {
+        if (collectionType == FullCollection)
+            return true;
+        return m_needsToBeVisited;
+    }
+
 private:
     static const unsigned singleCharacterStringCount = maxSingleCharacterString + 1;
@@ -95 +102 @@
     JS_EXPORT_PRIVATE void createSingleCharacterString(VM*, unsigned char);
 
-    void initialize(VM*, JSString*&, const char* value) const;
+    void initialize(VM*, JSString*&, const char* value);
 
     JSString* m_emptyString;
@@ -105 +112 @@
     JSString* m_singleCharacterStrings[singleCharacterStringCount];
     std::unique_ptr<SmallStringsStorage> m_storage;
+    bool m_needsToBeVisited;
 };