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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/205227">205227</a></dd>

<dt>Author</dt> <dd>bshafiei@apple.com</dd>

<dt>Date</dt> <dd>2016-08-31 00:19:55 -0700 (Wed, 31 Aug 2016)</dd>

</dl>

<h3>Log Message</h3>

<pre>Merge <a href="http://trac.webkit.org/projects/webkit/changeset/203802">r203802</a>. rdar://problem/27991569</pre>

<h3>Modified Paths</h3>

<ul>

<li><a href="#branchessafari602branchSourceJavaScriptCoreChangeLog">branches/safari-602-branch/Source/JavaScriptCore/ChangeLog</a></li>

<li><a href="#branchessafari602branchSourceJavaScriptCoredfgDFGBasicBlockh">branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGBasicBlock.h</a></li>

<li><a href="#branchessafari602branchSourceJavaScriptCoredfgDFGConstantFoldingPhasecpp">branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp</a></li>

<li><a href="#branchessafari602branchSourceJavaScriptCoredfgDFGConstantHoistingPhasecpp">branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantHoistingPhase.cpp</a></li>

<li><a href="#branchessafari602branchSourceJavaScriptCoredfgDFGGraphcpp">branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.cpp</a></li>

<li><a href="#branchessafari602branchSourceJavaScriptCoredfgDFGGraphh">branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.h</a></li>

<li><a href="#branchessafari602branchSourceJavaScriptCoredfgDFGPlancpp">branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGPlan.cpp</a></li>

</ul>

</div>

<div id="patch">

<h3>Diff</h3>

<a id="branchessafari602branchSourceJavaScriptCoreChangeLog"></a>

<div class="modfile"><h4>Modified: branches/safari-602-branch/Source/JavaScriptCore/ChangeLog (205226 => 205227)</h4>

<pre class="diff"><span>

<span class="info">--- branches/safari-602-branch/Source/JavaScriptCore/ChangeLog        2016-08-31 07:19:50 UTC (rev 205226)

+++ branches/safari-602-branch/Source/JavaScriptCore/ChangeLog        2016-08-31 07:19:55 UTC (rev 205227)

</span><span class="lines">@@ -1,5 +1,48 @@

</span><span class="cx"> 2016-08-30  Babak Shafiei  &lt;bshafiei@apple.com&gt;

</span><span class="cx"> 

</span><ins>+        Merge r203802. rdar://problem/27991569

+

+    2016-07-27  Benjamin Poulain  &lt;bpoulain@apple.com&gt;

+

+            [JSC] Fix a bunch of use-after-free of DFG::Node

+            https://bugs.webkit.org/show_bug.cgi?id=160228

+

+            Reviewed by Mark Lam.

+

+            FTL had a few places where we use a node after it has been

+            deleted. The dangling pointers come from the SSA liveness information

+            kept on the basic blocks.

+

+            This patch fixes the issues I could find and adds liveness invalidation

+            to help finding dependencies like these.

+

+            * dfg/DFGBasicBlock.h:

+            (JSC::DFG::BasicBlock::SSAData::invalidate):

+

+            * dfg/DFGConstantFoldingPhase.cpp:

+            (JSC::DFG::ConstantFoldingPhase::run):

+            Constant folding phase was deleting nodes in the loop over basic blocks.

+            The problem is the deleted nodes can be referenced by other blocks.

+            When the abstract interpreter was manipulating the abstract values of those

+            it was doing so on the dead nodes.

+

+            * dfg/DFGConstantHoistingPhase.cpp:

+            Just invalidation. Nothing wrong here since the useless nodes were

+            kept live while iterating the blocks.

+

+            * dfg/DFGGraph.cpp:

+            (JSC::DFG::Graph::killBlockAndItsContents):

+            (JSC::DFG::Graph::killUnreachableBlocks):

+            (JSC::DFG::Graph::invalidateNodeLiveness):

+

+            * dfg/DFGGraph.h:

+            * dfg/DFGPlan.cpp:

+            (JSC::DFG::Plan::compileInThreadImpl):

+            We had a lot of use-after-free in LCIM because we were using the stale

+            live nodes deleted by previous phases.

+

+2016-08-30  Babak Shafiei  &lt;bshafiei@apple.com&gt;

+

</ins><span class="cx">         Merge r203798. rdar://problem/27991578

</span><span class="cx"> 

</span><span class="cx">     2016-07-27  Keith Miller  &lt;keith_miller@apple.com&gt;

</span></span></pre></div>

<a id="branchessafari602branchSourceJavaScriptCoredfgDFGBasicBlockh"></a>

<div class="modfile"><h4>Modified: branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGBasicBlock.h (205226 => 205227)</h4>

<pre class="diff"><span>

<span class="info">--- branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGBasicBlock.h        2016-08-31 07:19:50 UTC (rev 205226)

+++ branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGBasicBlock.h        2016-08-31 07:19:55 UTC (rev 205227)

</span><span class="lines">@@ -239,6 +239,14 @@

</span><span class="cx">     struct SSAData {

</span><span class="cx">         WTF_MAKE_FAST_ALLOCATED;

</span><span class="cx">     public:

</span><ins>+        void invalidate()

+        {

+            liveAtTail.clear();

+            liveAtHead.clear();

+            valuesAtHead.clear();

+            valuesAtTail.clear();

+        }

+

</ins><span class="cx">         AvailabilityMap availabilityAtHead;

</span><span class="cx">         AvailabilityMap availabilityAtTail;

</span><span class="cx">         

</span></span></pre></div>

<a id="branchessafari602branchSourceJavaScriptCoredfgDFGConstantFoldingPhasecpp"></a>

<div class="modfile"><h4>Modified: branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp (205226 => 205227)</h4>

<pre class="diff"><span>

<span class="info">--- branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp        2016-08-31 07:19:50 UTC (rev 205226)

+++ branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp        2016-08-31 07:19:55 UTC (rev 205227)

</span><span class="lines">@@ -71,6 +71,7 @@

</span><span class="cx">             // It's now possible to simplify basic blocks by placing an Unreachable terminator right

<span class="cx">             // after anything that invalidates AI.

</span><span class="cx">             bool didClipBlock = false;

</span><ins>+            Vector&lt;Node*&gt; nodesToDelete;

</ins><span class="cx">             for (BasicBlock* block : m_graph.blocksInNaturalOrder()) {

</span><span class="cx">                 m_state.beginBasicBlock(block);

</span><span class="cx">                 for (unsigned nodeIndex = 0; nodeIndex &lt; block-&gt;size(); ++nodeIndex) {

</span><span class="lines">@@ -83,7 +84,7 @@

</span><span class="cx">                     if (!m_state.isValid()) {

</span><span class="cx">                         NodeOrigin origin = block-&gt;at(nodeIndex)-&gt;origin;

</span><span class="cx">                         for (unsigned killIndex = nodeIndex; killIndex &lt; block-&gt;size(); ++killIndex)

</span><del>-                            m_graph.m_allocator.free(block-&gt;at(killIndex));

</del><ins>+                            nodesToDelete.append(block-&gt;at(killIndex));

</ins><span class="cx">                         block-&gt;resize(nodeIndex);

</span><span class="cx">                         block-&gt;appendNode(m_graph, SpecNone, Unreachable, origin);

</span><span class="cx">                         didClipBlock = true;

</span><span class="lines">@@ -96,6 +97,12 @@

</span><span class="cx"> 

</span><span class="cx">             if (didClipBlock) {

</span><span class="cx">                 changed = true;

</span><ins>+

+                m_graph.invalidateNodeLiveness();

+

+                for (Node* node : nodesToDelete)

+                    m_graph.m_allocator.free(node);

+

</ins><span class="cx">                 m_graph.invalidateCFG();

</span><span class="cx">                 m_graph.resetReachability();

</span><span class="cx">                 m_graph.killUnreachableBlocks();

</span></span></pre></div>

<a id="branchessafari602branchSourceJavaScriptCoredfgDFGConstantHoistingPhasecpp"></a>

<div class="modfile"><h4>Modified: branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantHoistingPhase.cpp (205226 => 205227)</h4>

<pre class="diff"><span>

<span class="info">--- branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantHoistingPhase.cpp        2016-08-31 07:19:50 UTC (rev 205226)

+++ branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGConstantHoistingPhase.cpp        2016-08-31 07:19:55 UTC (rev 205227)

</span><span class="lines">@@ -128,6 +128,7 @@

</span><span class="cx">         }

</span><span class="cx">         

<span class="cx">         // And finally free the constants that we removed.

</span><ins>+        m_graph.invalidateNodeLiveness();

</ins><span class="cx">         for (Node* node : toFree)

</span><span class="cx">             m_graph.m_allocator.free(node);

</span><span class="cx">         

</span></span></pre></div>

<a id="branchessafari602branchSourceJavaScriptCoredfgDFGGraphcpp"></a>

<div class="modfile"><h4>Modified: branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.cpp (205226 => 205227)</h4>

<pre class="diff"><span>

<span class="info">--- branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.cpp        2016-08-31 07:19:50 UTC (rev 205226)

+++ branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.cpp        2016-08-31 07:19:55 UTC (rev 205227)

</span><span class="lines">@@ -744,6 +744,8 @@

</span><span class="cx"> 

</span><span class="cx"> void Graph::killBlockAndItsContents(BasicBlock* block)

</span><span class="cx"> {

</span><ins>+    if (auto&amp; ssaData = block-&gt;ssa)

+        ssaData-&gt;invalidate();

</ins><span class="cx">     for (unsigned phiIndex = block-&gt;phis.size(); phiIndex--;)

</span><span class="cx">         m_allocator.free(block-&gt;phis[phiIndex]);

</span><span class="cx">     for (unsigned nodeIndex = block-&gt;size(); nodeIndex--;)

</span><span class="lines">@@ -754,9 +756,8 @@

</span><span class="cx"> 

</span><span class="cx"> void Graph::killUnreachableBlocks()

</span><span class="cx"> {

<del>-    // FIXME: This probably creates dangling references from Upsilons to Phis in SSA.

-    // https://bugs.webkit.org/show_bug.cgi?id=159164

-    

</del><ins>+    invalidateNodeLiveness();

+

</ins><span class="cx">     for (BlockIndex blockIndex = 0; blockIndex &lt; numBlocks(); ++blockIndex) {

</span><span class="cx">         BasicBlock* block = this-&gt;block(blockIndex);

</span><span class="cx">         if (!block)

</span><span class="lines">@@ -778,6 +779,15 @@

</span><span class="cx">     m_backwardsCFG = nullptr;

</span><span class="cx"> }

</span><span class="cx"> 

</span><ins>+void Graph::invalidateNodeLiveness()

+{

+    if (m_form != SSA)

+        return;

+

+    for (BasicBlock* block : blocksInNaturalOrder())

+        block-&gt;ssa-&gt;invalidate();

+}

+

</ins><span class="cx"> void Graph::substituteGetLocal(BasicBlock&amp; block, unsigned startIndexInBlock, VariableAccessData* variableAccessData, Node* newGetLocal)

</span><span class="cx"> {

</span><span class="cx">     for (unsigned indexInBlock = startIndexInBlock; indexInBlock &lt; block.size(); ++indexInBlock) {

</span></span></pre></div>

<a id="branchessafari602branchSourceJavaScriptCoredfgDFGGraphh"></a>

<div class="modfile"><h4>Modified: branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.h (205226 => 205227)</h4>

<pre class="diff"><span>

<span class="info">--- branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.h        2016-08-31 07:19:50 UTC (rev 205226)

+++ branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGGraph.h        2016-08-31 07:19:55 UTC (rev 205227)

</span><span class="lines">@@ -533,6 +533,7 @@

</span><span class="cx">     void substituteGetLocal(BasicBlock&amp; block, unsigned startIndexInBlock, VariableAccessData* variableAccessData, Node* newGetLocal);

</span><span class="cx">     

</span><span class="cx">     void invalidateCFG();

</span><ins>+    void invalidateNodeLiveness();

</ins><span class="cx">     

</span><span class="cx">     void clearFlagsOnAllNodes(NodeFlags);

</span><span class="cx">     

</span></span></pre></div>

<a id="branchessafari602branchSourceJavaScriptCoredfgDFGPlancpp"></a>

<div class="modfile"><h4>Modified: branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGPlan.cpp (205226 => 205227)</h4>

<pre class="diff"><span>

<span class="info">--- branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGPlan.cpp        2016-08-31 07:19:50 UTC (rev 205226)

+++ branches/safari-602-branch/Source/JavaScriptCore/dfg/DFGPlan.cpp        2016-08-31 07:19:55 UTC (rev 205227)

</span><span class="lines">@@ -426,6 +426,8 @@

<span class="cx">         // wrong with running LICM earlier, if we wanted to put other CFG transforms above this point.

</span><span class="cx">         // Alternatively, we could run loop pre-header creation after SSA conversion - but if we did that

<span class="cx">         // then we'd need to do some simple SSA fix-up.

</span><ins>+        performLivenessAnalysis(dfg);

+        performCFA(dfg);

</ins><span class="cx">         performLICM(dfg);

</span><span class="cx"> 

<span class="cx">         // FIXME: Currently: IntegerRangeOptimization *must* be run after LICM.

</span></span></pre>

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