Attachment 362705 Details for Bug 194937 – Patch

[patch] Patch

bug-194937-20190222095847.patch (text/plain), 2.98 KB, created by Tadeu Zagallo on 2019-02-22 00:59:26 PST

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Creator: Tadeu Zagallo

Created: 2019-02-22 00:59:26 PST

Size: 2.98 KB

patch

obsolete

>Subversion Revision: 241937
>diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
>index 2c212dd8852421f0dadb6c8b8b6e9de5a2a0fdd4..d9b8a81b602c0c6bb9d61293d5b5eca02bffabc0 100644
>--- a/Source/JavaScriptCore/ChangeLog
>+++ b/Source/JavaScriptCore/ChangeLog
>@@ -1,3 +1,19 @@
>+2019-02-22  Tadeu Zagallo  <tzagallo@apple.com>
>+
>+        Avoid hashing CompactVariableEnvironment when decoding CompactVariableMap::Handle
>+        https://bugs.webkit.org/show_bug.cgi?id=194937
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Hashing the CompactVariableEnvironment is expensive and we could avoid it
>+        when decoding multiple handles to the same environment. This is sound because
>+        a pointer to the same CompactVariableEnvironment will hash the same.
>+
>+        * runtime/CachedTypes.cpp:
>+        (JSC::Decoder::handleForEnvironment const):
>+        (JSC::Decoder::setHandleForEnvironment):
>+        (JSC::CachedCompactVariableMapHandle::decode const):
>+
> 2019-02-22  Tadeu Zagallo  <tzagallo@apple.com>
> 
>         Remove unnecessary WTF:: prefixes in CachedTypes
>diff --git a/Source/JavaScriptCore/runtime/CachedTypes.cpp b/Source/JavaScriptCore/runtime/CachedTypes.cpp
>index a87adc7ccb7ec4607061c763f3b433220fd04431..9942993451fb1f91f014ff462c0033205b2157ce 100644
>--- a/Source/JavaScriptCore/runtime/CachedTypes.cpp
>+++ b/Source/JavaScriptCore/runtime/CachedTypes.cpp
>@@ -259,6 +259,19 @@ public:
>         m_finalizers.append(finalizer);
>     }
> 
>+    CompactVariableMap::Handle handleForEnvironment(CompactVariableEnvironment* environment) const
>+    {
>+        auto it = m_environmentToHandleMap.find(environment);
>+        ASSERT(it != m_environmentToHandleMap.end());
>+        return it->value;
>+    }
>+
>+    void setHandleForEnvironment(CompactVariableEnvironment* environment, const CompactVariableMap::Handle& handle)
>+    {
>+        auto addResult = m_environmentToHandleMap.add(environment, handle);
>+        ASSERT_UNUSED(addResult, addResult.isNewEntry);
>+    }
>+
> private:
>     VM& m_vm;
>     const uint8_t* m_baseAddress;
>@@ -267,6 +280,7 @@ private:
> #endif
>     HashMap<ptrdiff_t, void*> m_offsetToPtrMap;
>     Vector<std::function<void()>> m_finalizers;
>+    HashMap<CompactVariableEnvironment*, CompactVariableMap::Handle> m_environmentToHandleMap;
> };
> 
> template<typename T>
>@@ -938,15 +952,16 @@ public:
>     {
>         bool isNewAllocation;
>         CompactVariableEnvironment* environment = m_environment.decode(decoder, isNewAllocation);
>+        if (!isNewAllocation)
>+            return decoder.handleForEnvironment(environment);
>         bool isNewEntry;
>         CompactVariableMap::Handle handle = decoder.vm().m_compactVariableMap->get(environment, isNewEntry);
>-        if (!isNewAllocation)
>-            ASSERT(!isNewEntry);
>-        else if (!isNewEntry) {
>+        if (!isNewEntry) {
>             decoder.addFinalizer([=] {
>                 delete environment;
>             });
>         }
>+        decoder.setHandleForEnvironment(environment, handle);
>         return handle;
>     }
>

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