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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/184646">184646</a></dd>
<dt>Author</dt> <dd>fpizlo@apple.com</dd>
<dt>Date</dt> <dd>2015-05-20 11:40:42 -0700 (Wed, 20 May 2015)</dd>
</dl>
<h3>Log Message</h3>
<pre>Add some assertions about the CFG in the loop pre-header creation phase
https://bugs.webkit.org/show_bug.cgi?id=145205
Reviewed by Geoffrey Garen.
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::currentNodeOrigin): Add a FIXME.
* dfg/DFGLICMPhase.cpp:
(JSC::DFG::LICMPhase::run): Add a FIXME.
* dfg/DFGLoopPreHeaderCreationPhase.cpp:
(JSC::DFG::LoopPreHeaderCreationPhase::run): Add the assertions.</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceJavaScriptCoreChangeLog">trunk/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGByteCodeParsercpp">trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGLICMPhasecpp">trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGLoopPreHeaderCreationPhasecpp">trunk/Source/JavaScriptCore/dfg/DFGLoopPreHeaderCreationPhase.cpp</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/ChangeLog (184645 => 184646)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/ChangeLog 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/JavaScriptCore/ChangeLog 2015-05-20 18:40:42 UTC (rev 184646)
</span><span class="lines">@@ -1,3 +1,17 @@
</span><ins>+2015-05-19 Filip Pizlo <fpizlo@apple.com>
+
+ Add some assertions about the CFG in the loop pre-header creation phase
+ https://bugs.webkit.org/show_bug.cgi?id=145205
+
+ Reviewed by Geoffrey Garen.
+
+ * dfg/DFGByteCodeParser.cpp:
+ (JSC::DFG::ByteCodeParser::currentNodeOrigin): Add a FIXME.
+ * dfg/DFGLICMPhase.cpp:
+ (JSC::DFG::LICMPhase::run): Add a FIXME.
+ * dfg/DFGLoopPreHeaderCreationPhase.cpp:
+ (JSC::DFG::LoopPreHeaderCreationPhase::run): Add the assertions.
+
</ins><span class="cx"> 2015-05-20 Joseph Pecoraro <pecoraro@apple.com>
</span><span class="cx">
</span><span class="cx"> ES6: Implement Object.setPrototypeOf
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGByteCodeParsercpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp (184645 => 184646)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp 2015-05-20 18:40:42 UTC (rev 184646)
</span><span class="lines">@@ -607,6 +607,8 @@
</span><span class="cx">
</span><span class="cx"> NodeOrigin currentNodeOrigin()
</span><span class="cx"> {
</span><ins>+ // FIXME: We should set the forExit origin only on those nodes that can exit.
+ // https://bugs.webkit.org/show_bug.cgi?id=145204
</ins><span class="cx"> if (m_currentSemanticOrigin.isSet())
</span><span class="cx"> return NodeOrigin(m_currentSemanticOrigin, currentCodeOrigin());
</span><span class="cx"> return NodeOrigin(currentCodeOrigin());
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGLICMPhasecpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp (184645 => 184646)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp 2015-05-20 18:40:42 UTC (rev 184646)
</span><span class="lines">@@ -130,6 +130,12 @@
</span><span class="cx">
</span><span class="cx"> DFG_ASSERT(m_graph, preHeader->terminal(), preHeader->terminal()->op() == Jump);
</span><span class="cx">
</span><ins>+ // We should validate the pre-header. If we placed forExit origins on nodes only if
+ // at the top of that node it is legal to exit, then we would simply check if Jump
+ // had a forExit. We should disable hoisting to pre-headers that don't validate.
+ // Or, we could only allow hoisting of things that definitely don't exit.
+ // FIXME: https://bugs.webkit.org/show_bug.cgi?id=145204
+
</ins><span class="cx"> data.preHeader = preHeader;
</span><span class="cx"> }
</span><span class="cx">
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGLoopPreHeaderCreationPhasecpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGLoopPreHeaderCreationPhase.cpp (184645 => 184646)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGLoopPreHeaderCreationPhase.cpp 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/JavaScriptCore/dfg/DFGLoopPreHeaderCreationPhase.cpp 2015-05-20 18:40:42 UTC (rev 184646)
</span><span class="lines">@@ -88,11 +88,23 @@
</span><span class="cx"> existingPreHeader = predecessor;
</span><span class="cx"> continue;
</span><span class="cx"> }
</span><del>- if (existingPreHeader == predecessor)
- continue;
</del><ins>+ // We won't have duplicate entries in the predecessors list.
+ DFG_ASSERT(m_graph, nullptr, existingPreHeader != predecessor);
</ins><span class="cx"> needsNewPreHeader = true;
</span><span class="cx"> break;
</span><span class="cx"> }
</span><ins>+
+ // This phase should only be run on a DFG where unreachable blocks have been pruned.
+ // We also don't allow loops back to root. This means that every loop header has got
+ // to have a pre-header.
+ DFG_ASSERT(m_graph, nullptr, existingPreHeader);
+
+ // We are looking at the predecessors of a loop header. A loop header has to have
+ // some predecessor other than the pre-header. We must have broken critical edges
+ // because that is the DFG SSA convention. Therefore, each predecessor of the loop
+ // header must have only one successor.
+ DFG_ASSERT(m_graph, nullptr, existingPreHeader->terminal()->op() == Jump);
+
</ins><span class="cx"> if (!needsNewPreHeader)
</span><span class="cx"> continue;
</span><span class="cx">
</span></span></pre>
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