Title: [184646] trunk/Source/_javascript_Core
- Revision
- 184646
- Author
- [email protected]
- Date
- 2015-05-20 11:40:42 -0700 (Wed, 20 May 2015)
Log Message
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.
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (184645 => 184646)
--- trunk/Source/_javascript_Core/ChangeLog 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/_javascript_Core/ChangeLog 2015-05-20 18:40:42 UTC (rev 184646)
@@ -1,3 +1,17 @@
+2015-05-19 Filip Pizlo <[email protected]>
+
+ 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.
+
2015-05-20 Joseph Pecoraro <[email protected]>
ES6: Implement Object.setPrototypeOf
Modified: trunk/Source/_javascript_Core/dfg/DFGByteCodeParser.cpp (184645 => 184646)
--- trunk/Source/_javascript_Core/dfg/DFGByteCodeParser.cpp 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/_javascript_Core/dfg/DFGByteCodeParser.cpp 2015-05-20 18:40:42 UTC (rev 184646)
@@ -607,6 +607,8 @@
NodeOrigin currentNodeOrigin()
{
+ // FIXME: We should set the forExit origin only on those nodes that can exit.
+ // https://bugs.webkit.org/show_bug.cgi?id=145204
if (m_currentSemanticOrigin.isSet())
return NodeOrigin(m_currentSemanticOrigin, currentCodeOrigin());
return NodeOrigin(currentCodeOrigin());
Modified: trunk/Source/_javascript_Core/dfg/DFGLICMPhase.cpp (184645 => 184646)
--- trunk/Source/_javascript_Core/dfg/DFGLICMPhase.cpp 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/_javascript_Core/dfg/DFGLICMPhase.cpp 2015-05-20 18:40:42 UTC (rev 184646)
@@ -130,6 +130,12 @@
DFG_ASSERT(m_graph, preHeader->terminal(), preHeader->terminal()->op() == Jump);
+ // 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
+
data.preHeader = preHeader;
}
Modified: trunk/Source/_javascript_Core/dfg/DFGLoopPreHeaderCreationPhase.cpp (184645 => 184646)
--- trunk/Source/_javascript_Core/dfg/DFGLoopPreHeaderCreationPhase.cpp 2015-05-20 17:58:37 UTC (rev 184645)
+++ trunk/Source/_javascript_Core/dfg/DFGLoopPreHeaderCreationPhase.cpp 2015-05-20 18:40:42 UTC (rev 184646)
@@ -88,11 +88,23 @@
existingPreHeader = predecessor;
continue;
}
- if (existingPreHeader == predecessor)
- continue;
+ // We won't have duplicate entries in the predecessors list.
+ DFG_ASSERT(m_graph, nullptr, existingPreHeader != predecessor);
needsNewPreHeader = true;
break;
}
+
+ // 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);
+
if (!needsNewPreHeader)
continue;
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