Changeset 92593 in webkit for trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h

Timestamp:

Aug 8, 2011, 5:50:59 AM (14 years ago)

Author:

[email protected]

Message:

DFG JIT does not track speculation decisions for global variables
​https://bugs.webkit.org/show_bug.cgi?id=65825

Reviewed by Gavin Barraclough.

Added the capability to track predictions for global variables, and
ensured that code can abstract over the source of prediction (local
versus global variable) wherever it is appropriate to do so. Also
cleaned up the code in SpeculativeJIT that decides how to speculate
based on recorded predictions (for example instead of using isInteger,
which makes sense for local predictions where the GetLocal would
return an integer value, we now tend to use shouldSpeculateInteger,
which checks if the value is either already an integer or should be
speculated to be an integer).

This is an 0.8% win on SunSpider, almost entirely thanks to a 25%
win on controlflow-recursive. It's also a 4.8% win on v8-crypto.

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::predictArray):
(JSC::DFG::ByteCodeParser::predictInt32):
(JSC::DFG::ByteCodeParser::parseBlock):

• dfg/DFGGraph.cpp:

(JSC::DFG::Graph::dump):

• dfg/DFGGraph.h:

(JSC::DFG::Graph::predictGlobalVar):
(JSC::DFG::Graph::predict):
(JSC::DFG::Graph::getGlobalVarPrediction):
(JSC::DFG::Graph::getPrediction):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::SpeculativeJIT::shouldSpeculateInteger):
(JSC::DFG::SpeculativeJIT::shouldSpeculateDouble):

File:

• trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h (modified) (3 diffs)

trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h

@@ -156 +156 @@
             || (info.spillFormat() | DataFormatJS) == DataFormatJSInteger;
     }
-
-    bool isRegisterDataFormatDouble(NodeIndex nodeIndex)
+    
+    bool shouldSpeculateInteger(NodeIndex nodeIndex)
+    {
+        if (isInteger(nodeIndex))
+            return true;
+        
+        if (isInt32Prediction(m_jit.graph().getPrediction(m_jit.graph()[nodeIndex])))
+            return true;
+        
+        return false;
+    }
+
+    bool shouldSpeculateDouble(NodeIndex nodeIndex)
     {
         Node& node = m_jit.graph()[nodeIndex];
@@ -167 +178 @@
             return true;
         
-        if (node.op == GetLocal && isDoublePrediction(m_jit.graph().getPrediction(node.local())))
+        if (isDoublePrediction(m_jit.graph().getPrediction(node)))
             return true;
         
@@ -175 +186 @@
     bool shouldSpeculateInteger(NodeIndex op1, NodeIndex op2)
     {
-        return !(isRegisterDataFormatDouble(op1) || isRegisterDataFormatDouble(op2)) && (isInteger(op1) || isInteger(op2));
+        return !(shouldSpeculateDouble(op1) || shouldSpeculateDouble(op2)) && (shouldSpeculateInteger(op1) || shouldSpeculateInteger(op2));
     }