[webkit-changes] [207186] trunk/Source/JavaScriptCore

[sbarati]

Title: [207186] trunk/Source/_javascript_Core

Revision

207186

Author

sbar...@apple.com

Date

2016-10-11 20:14:56 -0700 (Tue, 11 Oct 2016)

Log Message

HasOwnPropertyCache needs to ref the UniquedStringImpls it sees
https://bugs.webkit.org/show_bug.cgi?id=163255

Reviewed by Geoffrey Garen.

The cache needs to be responsible for ensuring that things
in the cache stay alive. Before, it wasn't doing this, and
that was wrong.

* runtime/HasOwnPropertyCache.h:
(JSC::HasOwnPropertyCache::Entry::operator=):
(JSC::HasOwnPropertyCache::operator delete):
(JSC::HasOwnPropertyCache::create):
(JSC::HasOwnPropertyCache::get):
(JSC::HasOwnPropertyCache::tryAdd):
(JSC::HasOwnPropertyCache::clear):
(JSC::HasOwnPropertyCache::zeroBuffer):

Modified Paths

• trunk/Source/_javascript_Core/ChangeLog
• trunk/Source/_javascript_Core/runtime/HasOwnPropertyCache.h

Diff

Modified: trunk/Source/_javascript_Core/ChangeLog (207185 => 207186)

--- trunk/Source/_javascript_Core/ChangeLog	2016-10-12 02:24:50 UTC (rev 207185)
+++ trunk/Source/_javascript_Core/ChangeLog	2016-10-12 03:14:56 UTC (rev 207186)
@@ -1,3 +1,23 @@
+2016-10-11  Saam Barati  <sbar...@apple.com>
+
+        HasOwnPropertyCache needs to ref the UniquedStringImpls it sees
+        https://bugs.webkit.org/show_bug.cgi?id=163255
+
+        Reviewed by Geoffrey Garen.
+
+        The cache needs to be responsible for ensuring that things
+        in the cache stay alive. Before, it wasn't doing this, and
+        that was wrong.
+
+        * runtime/HasOwnPropertyCache.h:
+        (JSC::HasOwnPropertyCache::Entry::operator=):
+        (JSC::HasOwnPropertyCache::operator delete):
+        (JSC::HasOwnPropertyCache::create):
+        (JSC::HasOwnPropertyCache::get):
+        (JSC::HasOwnPropertyCache::tryAdd):
+        (JSC::HasOwnPropertyCache::clear):
+        (JSC::HasOwnPropertyCache::zeroBuffer):
+
 2016-10-06  Filip Pizlo  <fpi...@apple.com>
 
         MarkedBlock should know what objects are live during marking

Modified: trunk/Source/_javascript_Core/runtime/HasOwnPropertyCache.h (207185 => 207186)

--- trunk/Source/_javascript_Core/runtime/HasOwnPropertyCache.h	2016-10-12 02:24:50 UTC (rev 207185)
+++ trunk/Source/_javascript_Core/runtime/HasOwnPropertyCache.h	2016-10-12 03:14:56 UTC (rev 207186)
@@ -42,9 +42,19 @@
         static ptrdiff_t offsetOfImpl() { return OBJECT_OFFSETOF(Entry, impl); }
         static ptrdiff_t offsetOfResult() { return OBJECT_OFFSETOF(Entry, result); }
 
-        UniquedStringImpl* impl;
-        StructureID structureID;
-        bool result;
+        Entry() = default;
+
+        Entry& operator=(Entry&& other)
+        {
+            impl = WTFMove(other.impl);
+            structureID = other.structureID;
+            result = other.result;
+            return *this;
+        }
+
+        RefPtr<UniquedStringImpl> impl { };
+        StructureID structureID { 0 };
+        bool result { false };
     };
 
     HasOwnPropertyCache() = delete;
@@ -51,6 +61,7 @@
 
     void operator delete(void* cache)
     {
+        static_cast<HasOwnPropertyCache*>(cache)->clear();
         fastFree(cache);
     }
 
@@ -58,7 +69,7 @@
     {
         size_t allocationSize = sizeof(Entry) * size;
         HasOwnPropertyCache* result = static_cast<HasOwnPropertyCache*>(fastMalloc(allocationSize));
-        result->clear();
+        result->clearBuffer();
         return result;
     }
 
@@ -73,7 +84,7 @@
         StructureID id = structure->id();
         uint32_t index = HasOwnPropertyCache::hash(id, impl) & mask;
         Entry& entry = bitwise_cast<Entry*>(this)[index];
-        if (entry.structureID == id && entry.impl == impl)
+        if (entry.structureID == id && entry.impl.get() == impl)
             return entry.result;
         return Nullopt;
     }
@@ -104,14 +115,26 @@
             UniquedStringImpl* impl = propName.uid();
             StructureID id = structure->id();
             uint32_t index = HasOwnPropertyCache::hash(id, impl) & mask;
-            bitwise_cast<Entry*>(this)[index] = Entry{ impl, id, result };
+            bitwise_cast<Entry*>(this)[index] = Entry{ RefPtr<UniquedStringImpl>(impl), id, result };
         }
     }
 
     void clear()
     {
-        memset(this, 0, sizeof(Entry) * size);
+        Entry* buffer = bitwise_cast<Entry*>(this);
+        for (uint32_t i = 0; i < size; ++i)
+            buffer[i].Entry::~Entry();
+
+        clearBuffer();
     }
+
+private:
+    void clearBuffer()
+    {
+        Entry* buffer = bitwise_cast<Entry*>(this);
+        for (uint32_t i = 0; i < size; ++i)
+            new (&buffer[i]) Entry();
+    }
 };
 
 ALWAYS_INLINE HasOwnPropertyCache* VM::ensureHasOwnPropertyCache()

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