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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/189070">189070</a></dd>
<dt>Author</dt> <dd>fpizlo@apple.com</dd>
<dt>Date</dt> <dd>2015-08-27 16:41:59 -0700 (Thu, 27 Aug 2015)</dd>
</dl>
<h3>Log Message</h3>
<pre>Unreviewed, fix some FIXMEs and add some new ones, based on things we've learned from some
recent OSR exit work.
* dfg/DFGLICMPhase.cpp:
(JSC::DFG::LICMPhase::run):
(JSC::DFG::LICMPhase::attemptHoist):
* dfg/DFGMayExit.cpp:
* dfg/DFGMayExit.h:</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceJavaScriptCoreChangeLog">trunk/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGLICMPhasecpp">trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGMayExitcpp">trunk/Source/JavaScriptCore/dfg/DFGMayExit.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGMayExith">trunk/Source/JavaScriptCore/dfg/DFGMayExit.h</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/ChangeLog (189069 => 189070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/ChangeLog 2015-08-27 23:40:04 UTC (rev 189069)
+++ trunk/Source/JavaScriptCore/ChangeLog 2015-08-27 23:41:59 UTC (rev 189070)
</span><span class="lines">@@ -1,3 +1,14 @@
</span><ins>+2015-08-27 Filip Pizlo <fpizlo@apple.com>
+
+ Unreviewed, fix some FIXMEs and add some new ones, based on things we've learned from some
+ recent OSR exit work.
+
+ * dfg/DFGLICMPhase.cpp:
+ (JSC::DFG::LICMPhase::run):
+ (JSC::DFG::LICMPhase::attemptHoist):
+ * dfg/DFGMayExit.cpp:
+ * dfg/DFGMayExit.h:
+
</ins><span class="cx"> 2015-08-27 Keith Miller <keith_miller@apple.com>
</span><span class="cx">
</span><span class="cx"> [ES6] Add TypedArray.prototype functionality.
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGLICMPhasecpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp (189069 => 189070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp 2015-08-27 23:40:04 UTC (rev 189069)
+++ trunk/Source/JavaScriptCore/dfg/DFGLICMPhase.cpp 2015-08-27 23:41:59 UTC (rev 189070)
</span><span class="lines">@@ -130,11 +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><del>- // 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
</del><ins>+ // We should validate the pre-header. This currently assumes that it's valid to OSR exit at
+ // the Jump of the pre-header. That may not always be the case, like if we lowered a Node
+ // that was ExitInvalid to a loop. This phase should somehow defend against this - at the
+ // very least with assertions, if not with something better (like only hoisting things that
+ // cannot exit).
+ // FIXME: https://bugs.webkit.org/show_bug.cgi?id=148259
</ins><span class="cx">
</span><span class="cx"> data.preHeader = preHeader;
</span><span class="cx"> }
</span><span class="lines">@@ -283,16 +284,18 @@
</span><span class="cx"> " Hoisting ", node, " from ", *fromBlock, " to ", *data.preHeader,
</span><span class="cx"> "\n");
</span><span class="cx"> }
</span><del>-
</del><ins>+
+ // FIXME: We should adjust the Check: flags on the edges of node. There are phases that assume
+ // that those flags are correct even if AI is stale.
+ // https://bugs.webkit.org/show_bug.cgi?id=148544
</ins><span class="cx"> data.preHeader->insertBeforeTerminal(node);
</span><span class="cx"> node->owner = data.preHeader;
</span><span class="cx"> NodeOrigin originalOrigin = node->origin;
</span><span class="cx"> node->origin = data.preHeader->terminal()->origin.withSemantic(node->origin.semantic);
</span><span class="cx">
</span><span class="cx"> // Modify the states at the end of the preHeader of the loop we hoisted to,
</span><del>- // and all pre-headers inside the loop.
- // FIXME: This could become a scalability bottleneck. Fortunately, most loops
- // are small and anyway we rapidly skip over basic blocks here.
</del><ins>+ // and all pre-headers inside the loop. This isn't a stability bottleneck right now
+ // because most loops are small and most blocks belong to few loops.
</ins><span class="cx"> for (unsigned bodyIndex = loop->size(); bodyIndex--;) {
</span><span class="cx"> BasicBlock* subBlock = loop->at(bodyIndex);
</span><span class="cx"> const NaturalLoop* subLoop = m_graph.m_naturalLoops.headerOf(subBlock);
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGMayExitcpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGMayExit.cpp (189069 => 189070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGMayExit.cpp 2015-08-27 23:40:04 UTC (rev 189069)
+++ trunk/Source/JavaScriptCore/dfg/DFGMayExit.cpp 2015-08-27 23:41:59 UTC (rev 189070)
</span><span class="lines">@@ -45,6 +45,8 @@
</span><span class="cx">
</span><span class="cx"> void operator()(Node*, Edge edge)
</span><span class="cx"> {
</span><ins>+ // FIXME: Maybe this should call mayHaveTypeCheck(edge.useKind()) instead.
+ // https://bugs.webkit.org/show_bug.cgi?id=148545
</ins><span class="cx"> if (edge.willHaveCheck()) {
</span><span class="cx"> m_result = true;
</span><span class="cx"> return;
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGMayExith"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGMayExit.h (189069 => 189070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGMayExit.h 2015-08-27 23:40:04 UTC (rev 189069)
+++ trunk/Source/JavaScriptCore/dfg/DFGMayExit.h 2015-08-27 23:41:59 UTC (rev 189070)
</span><span class="lines">@@ -66,6 +66,12 @@
</span><span class="cx"> Exits
</span><span class="cx"> };
</span><span class="cx">
</span><ins>+// FIXME: This currently consumes the Check: flag produced by AI, and will claim that something doesn't
+// exit if the Check: flag was cleared. This makes it hard to use mayExit() for things like hoisting
+// (for example in LICM), since that wants to know if the node would exit if it was moved somewhere
+// else.
+// https://bugs.webkit.org/show_bug.cgi?id=148545
+
</ins><span class="cx"> ExitMode mayExit(Graph&, Node*);
</span><span class="cx">
</span><span class="cx"> } } // namespace JSC::DFG
</span></span></pre>
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